Hello, I am Professor John Kelly and this is the WeberAuto YouTube channel in this episode we
will be exploring the high voltage battery from the original 2011 Nissan Leaf electric vehicle.
Now this is one of the most controversial battery designs out there mainly because of the lack of an
active cooling system to remove the heat from the battery but we will look at the individual pieces
and totally reassemble this battery in this video now before we get doing that I need to thank the
good people at Green Tech Auto hybrid batteries we would not have this battery to look at today
if it weren't for the folks at Green Tech Auto Hybrid batteries and what they do different from
other companies is they have deals with salvage yards and and wrecking yards here in the United
States where they buy batteries hybrid batteries and electric vehicle batteries from salvage yards
from vehicles that have been in automobile accidents and they take them apart they test
all the individual cells or cell modules and make sure that everything is in good shape if there's
bad parts they will swap them out with good parts from other batteries they have obtained from other
self yards so if I was running a business that sold used hybrid and electric batteries that's
exactly how I would do it Green Tech auto hybrid has been in business for over eight years and they
have 19 locations in North America so check out their website I put a link in the video
description down below so thank you to the people at green tech out or hybrid batteries
alright let's start looking at some of the parts the biggest and most obvious pieces inside the
Nissan Leaf battery are the battery modules so this is one battery module right here and it has
a positive terminal a negative terminal and a voltage sensing terminal and inside of this are
four lithium ion pouch cells very similar to this chevrolet volt lithium-ion battery pouch so there
are two sets of these four of them in two pairs of two so two of these are welded together and
then two more are welded together and then they are put in series positive to negative inside of
one of these battery modules well I'm not content with just having that be the the smallest piece
that we look at in this battery because there's there's got to be some interesting things to
look at inside there so I decided I don't want to open one of those battery modules up and and see
how its configured I want to I want to look at it but the the housing isn't made to be opened and I
got looking real close an adit and if you look real close right at the edge there it actually
looks like the edge of a can of tuna or some other canned good and so I thought hey I wonder if I can
use a can opener to open that up now don't do this a home folks don't use the can opener to open it
but when my wife wasn't looking I grabbed her can opener and I used it on this battery module right
here and sure enough I was able to cut from the top all the way down and around and back to open
up one of these modules now I say don't do this at home because if you short-circuit something in
here there's a big risk of fire and I just highly recommend that you do not even try that I did it
in an environment where it wouldn't hurt anything unless I couldn't get out of the way fast enough
so let's open up a battery module of a Nissan Leaf all right now there's some information I put
on the labels on the front of this battery module that apply it to the rest of these battery modules
and the whole battery as a whole the first thing is the nominal voltage is 7.5 volts and nominal
means it's neither charged nor discharged it's just that's its normal voltage there are 48 of
these 7 point 5 volt modules inside of the Nissan Leaf battery and that if you take 48 times 7.5
you get 360 volts as the nominal voltage for the entire battery pack all right this battery pack
is rated for 24 kilowatt hours and 60 amp hours so let's open this up and take a look inside as
I take off the front cover which was glued on this blue piece of material here which I believe is a
heat transfer material has a real sticky tacky adhesive right there and it was all I could do
to get this off without bending it it was it was rough okay now I had to manually cut the aluminum
on the top to get the lid off but now we can rock out the rest of it just like that and of course
the back side also was glued to the bottom of the module housing and so I had to carefully take that
off to see inside now if you look closely at the edge here you can see that there are one two three
four of the lithium ion pouches now there's a top cover right here that comes off next
just a little pocket screwdriver and some little tabs to release on each side there
we go and I'll lift that up so now here's the bottom view which we still can't see very much
and then there's the top view where we can see some connections at the top here this
is only seven and a half volts I don't need high voltage gloves I don't need personal
protective equipment you still need to not let these to short out or touch something
conductive like the stainless steel top of my workbench here you got to be real
careful and be cautious of those even though it's just seven and a half volts all right
on the backside there is another little cover plate to take off right there and now we can
see on the back some of the connections now I wanted to make some sense of these electrical
connections and as I said before we have four of these lithium-ion cell pouches in here
so I wanted to open them up but they're glued each one is glued to each other I'm sure for heat
transfer and so I thought well I've come this far let's let's keep going there's some little
dowel pins that have to come out here the hold the support housings for the electrical connections on
all four of these pouches so I have to take out two on the bottom and two on the top dowel pins
now with that with those dowel pins taken out I could see that I could get in and try to separate
it which eventually I got it separated but you can't separate it without cutting the electrical
connections right here on the top so I cut between here and here and here and here on the one side so
that I could open this up so I'm going to open it now it opens like this so now I have two 3.75
volt pouches and notice this pouch in comparison with the Chevrolet Volt pouch is much larger and
we would expect it to be the volt battery was a smaller kilowatt-hour battery 16 I believe
in this one's 24 kilowatt hour so to make sense electrically of how these pouches are wired as
I showed you on the Chevrolet Volt pouch there's a positive terminal and a negative terminal sticking
up at the top of the pouch so you can see right here one of the terminals coming up and it has
a positive symbol on a sticker right there so that this pouch right here that's its positive terminal
and it comes up and if it is welded to this copper bus bar that then has the positive terminal from
the front pouch welded together so that puts it in parallel same with the two negative terminals
right there so these two lithium ion pouches are in parallel with each other but then coming off
of the negative terminal we have a bus bar where I had to cut the connections from the other pair
of cell pouches so they connect where I cut it it connects right here and that is the positive two
terminals of a set of cells and the negative two terminals are over here so negative positive that
positive connected to the negative of this other set of cells and then here's it's positive so
we have two sets of two parallel cell pouches in series with each other so two pouches in parallel
with each other here two more pouches in parallel here and we just put the two in series with each
other with this one common connection fold it back together to complete the cell module now I wanted
to know what is this Center screw here well that Center screw on the front pouch just goes between
the center screw and the positive terminal and the center screw connects to the negative terminal
of the front pouch and so that will give us the cell pack voltage to parallel cell pack voltage
of just two of the four of these cell pouches then if you go between that same screw and the
negative terminal through that bus bar that I cut the connections on it gives us the voltage of the
other set of parallel pouches so it's just the center screw and the negative we measure
the front two pouches and from the center screw to the positive we measure the rear two pouches
on this module now there are two different part numbers of the module on the early Leafs and the
only difference between them is which side is positive which is negative you can see on the
positive side as a red terminal negative side has a black terminal you've got to pay real
close attention to how these came apart inside of the battery itself so you get your everything in
series with each other positive negative positive negative positive negative otherwise you'll lose
some of your power by putting positive to positive or negative to negative okay well that was scary
for me to disassemble as afraid I was going to short-circuit something or catch something on fire
but it ended up being a good good experiment let me grab a module that has not been disassembled
this one right here and let's take a measurement from the center terminal to the negative Center
terminal to the positive if I go from the center terminal to the positive terminal I read three
point seven nine four volts if I go from the center terminal to the negative terminal I
read three point seven nine seven volts so three millivolts point zero zero three volt difference
between the two sets of parallel pouches inside of the battery module now there's a computer
called the lithium ion battery controller on the end of the rear stack of battery modules and one
of the jobs of that computer is to monitor these voltages and then try to balance them by keeping
the voltages within a certain range we want these to be as equal as possible if you're
ever going to go in and replace one of these modules or replace an entire stack of modules
then you need to make sure that the voltage of the module you're putting in matches the voltage
of the modules that are already there otherwise it will trigger our trouble code and may not even
let the vehicle move at all so I believe there's a scan tool function to draw down the power of a
certain cell module and there's a other ways to do it with resistive load as well but you you've
got to have these at the same voltage I forgot to take one more measurement with the battery module
while it's here just both cells both parallel cells put in series combined here so we'll go
from positive to negative we get seven point five nine volts on this cell right here now according
to the scan tool data these can be the allowable range are on the scan tool without triggering a
trouble code is as high as four point two volts and as low as three point two volts okay as I
said before there are three one to three stacks of these modules where we just stack up modules
this particular stack goes on the right hand side of our empty battery housing over there this one's
our left-hand stack and this one in the rear is called the rear stack so the right-hand stack is
six kilowatt hour rating the left-hand stack is six kilowatt hour and the rear stack is twelve
kilowatt hour for a total of 24 kilowatt hour now as I showed you on those modules each one has its
own positive and negative terminal positive red negative black and these modules have to be put in
a certain order so that as we connect positive to negative positive connect negative we put
everything in series to build up the total voltage of this now in this stack here the right hand and
the left hand stacks there are 12 7 point 5 volt nominal modules which means makes this module B
not up to 90 volts if it was totally connected together which it is not right now all the bus
bars are removed so the highest voltage that we have is the seven and a half volts that are
right here so we've got 90 volts here 90 volts here that's 180 and then we have 180 volts on
the rear stack as well so 180 + 180 gives us 360 volts now as you could see on the side of these
battery modules I've known each one of them and if you're doing any service work on this battery you
need to know which module is which because there are up to five different trouble codes per set
of parallel cells which means up to ten trouble codes per module and if you get a trouble code
for a certain module and you decide well I need to go in and replace just that module which you can
do after downloading and purchasing hundreds of dollars worth of Nissan Leaf service information
and training information the Nissan Leaf battery was originally designed and still is to be fully
serviceable as far as going in and replacing any part that you want I don't think it's had to have
a lot of internal pieces replaced the biggest problem has been the the batteries own capacity
decreasing and decreasing the drivable range of the vehicle but the point I'm getting to here
is the number or these modules are not numbered and so there's this little map that I found in
the training material that shows as you can see here sort of where each battery module is and so
it took a little bit of it of figuring out and in interpreting to find that so if you look at this
battery stack right here the lowest battery module number is module 37 right here and so we start at
37 and then go to 38 up to 39 over to 40 up to 41 or over 42 up to 43 over to 44 and then there's
a connection that comes down over here to 45 46 47 and 48 so that's 12 modules in a unique order
in which they need to be electrically connected together with the bus bars now the left hand stack
is laid out differently than the right hand stack they look identical but which module is which the
order that the modules are placed in series with each other is totally different and then on this
giant rear stack right here module one is clear down there on the other side and it just simply
goes two three four five six all the way through module twenty four right here and then we pick up
module twenty five right here and that winds its way through up to module thirty six which then
connects to module thirty seven and then all the way through to module forty eight now on
this battery module forty eight is the overall battery negative that you'll see will connect
to the junction block the inside the battery that when turned on will send power to the inverter up
underneath the hood module number one down there on the rear stack is overall battery positive
and so we'll see that here in a little bit so of course there are specific torque values for each
one of these module bolts if I turn this module just a little bit here I can take off since I've
already loosened the bolts what's called an end bracket so if i loosen this up I can lift off
and end bracket and then just lift up one module like this module forty six which is no different
than the one we just looked at and every one of these modules are identical other than the
polarity which is positive which is negative but the thing you need to know about assembling one
of these is that there are spacers there's a module spacer in between each set of modules
so that when you torque the bolts down it's not squishing the housings of the modules together
it keeps a little bit of an air gap between it which I'm sure the intent was to help cool the
battery helped keep the battery cool but as I mentioned at the start of this video there is
no liquid cooling system there's no refrigerant type cooling system like some of the BMWs have
there's no air blowing through it like Toyotas have there is nothing to keep this battery cool
when you put the lid on that battery case that I showed you at the start of the video and bolt
it down it's a hermetically sealed no air in or out there are some vents for atmospheric
pressure changes as you drive up and down high elevation mountains and so on but that does not
allow airflow through the system and and so it's just a totally sealed box and no place for the
heat to get out now he you can transfer heat if you remember from basic physics at least my basic
physics through conduction where we physically touch some hotter some item that's hotter to
something that's cooler and the heat transfers to the cooler item there's convection where something
is really hot and it heats the air up around it and then the error dissipates the heat and then
there's radiation like the sunlight where there's heat being transferred as long as you're not in
the shadow well the majority of the heat transfer through the the Nissan Leaf battery is conduction
to the outer housing and then convection to the air and that's it which is unfortunate
for the the design as it's turned out to be if you especially if you live in very hot climates
areas of the world where it's very hot that's a problem for Nissan Leaf batteries if you leave
live somewhere temperate or cool temperatures cold temperatures then you're probably alright
and haven't had any problems but I wanted to show you there is absolutely nothing here to
remove heat except for just thermal conduction and convection all right so there are two
module spacers they have to be lined up with the holes then we just start stacking the modules
on top of each other obviously we stack four up over here we're only stacking two up here there's
a warning in the service information about proper alignment of the modules themselves and I'll show
you what that what they're talking about there so if I put these bolts down in and get them started
by hand there we go these bolts are started by hand but I can still twist these upper modules
and they tell you don't put it together with it twisted especially on this rear stack here
they want you to get a straight edge and put it along the modules before you tighten the bolts
down they'll hold them all together in the stack to make sure that everything is aligned properly
now disassembling these is easy you just undo the bolts and take them out but on this rear stack it
has big studs that go all the way from one side to the other and you're laying these modules on
their side and so it could be a little harder to get them aligned as you put it back together
they recommend that as you disassemble it and and remove the nuts from the studs that go all
the way through here that you put a big sense strap around it to keep the modules from falling
apart whenever you're disassembling that because if they start if they start to fall especially
if you're you've got some sort of a conductive tabletop which you should not be using if you're
going to be disassembling those parts some of the modules might fall and get somewhere where they
could short out or cause other type of damage so we want these as straight as possible before we
torque them down and there is a specific twerk for these I found it interesting in the Nissan
Leaf service manual they don't give you the bolt torque for for these bolts they just say torque
the bolt and so I looked in the service manual and tried to find torque specs a whole section of
specifications for torque I couldn't find it the only thing I could find was a table with general
torque ratings for specific types of bolts so if I just missed it please write something in
the comments down below but I could not find the torque specs in the service manual however
in the instructor guide for the Nissan Leaf Evy technologies both the 2014 version out of 2018
version it does give the torque specifications which I was relieved to find and so the torque
spec on these hold down bolts right here is not very much 9.6 Newton meters or 85 inch pounds
not foot-pounds inch pounds so that's between 7 and 8 foot pounds so if you have an inch
pound torque wrench 85 inch pounds let me grab mine I'm going to Snug these up by hand first
okay they just wanted to use a cross pattern as you tighten these bolts down to specification so
we will go to 85 now if this was the end stack nuts that we're tightening up on the studs that
go through they want you to do it twice they want you to check the full torque twice okay so
this is the outside of the vehicle view of these modules but now let's take a look at the elect
Kohl's side the inside view so now we can see all of the terminals sticking out of the modules so
we've got negative and then that the center voltage sensing terminal and then positive
so notice we have negative positive negative positive and then down below we have positive
negative positive negative this whole row going all the way across has the negative on the left
the very bottom row has the positive on the left and this other one over here will be a
little bit different and so somehow we need to connect the modules in numerical order together
in the proper series configuration so for that there's a special bus bar that these batteries
come with okay this is the bus bar assembly for this right-hand battery stack and as you can see
it has metal bus bars that will go from one module over to the next jumping the big gap right here
and then it has short little ones right here that go up and down to go to change rows to go from one
row to the next row and then it also has a whole bunch of little tiny wires here for the center tap
on these modules for the voltage sensing between the two terminals and so this harness or this bus
bar assembly here made by Yuzuki is the one that goes on here it actually snaps in place over these
terminals that they have a little lip right there and so we will set this down on here for those
of you thinking he doesn't have his personal protective equipment or his high of all these
gloves on this is not high voltage so a word on on high voltage the federal motor vehicle safety
standards define high voltage on an automobile as anything sixty volts DC or higher or thirty
volts AC or higher the National Fire Protection Association and the Department of Energy define
it as one hundred volts DC or higher for needing personal protective equipment or half of that 50
volts ac for personal protective equipment needs now that these are this is a DC battery so we're
below the 100 volts this is a 90 volt battery right here because there's confusion between DC
and AC voltage levels that are safe I believe that most vehicle manufacturers have picked
the 50 volt AC as the rule say anything above 50 volts you need to have personal protective
equipment on well that that's extra safe and I'm not arguing with that it's just that the
DC voltage rating is typically almost double of the AC voltage rating for personal protective
equipment so I'm I I do have insulated tools right here I'm going to use to put this together but I'm
not not going to wear high voltage gloves until we start connecting the 90 volt stack to another
90 volt stack into the 180 volt stack because there's there's no need to do so so the bolt
torque on these little tiny bolts that holds each bus bar to the positive or negative terminal is
5.5 Newton meters or 49 inch pounds which is less than five foot-pounds well it's just a little over
4 foot pounds so most technicians don't even have a torque wrench that goes to as little as
4 foot-pounds you need to get out an inch pound torque wrench like I used to tighten those bolts
down and torque those so I'm going to put these in and then we'll torque them the nuts that I'm
tightening these bolts down into are held in place inside of the little plastic pieces coming out of
those modules so you don't want to use any type of an electric or impact gun installing these
because you can or removing them either because you can break that nut loose inside the plastic
all right so I've got all of the busbar bolts in place and we'll torque those here in just a moment
now we need to put in the little screws for the voltage sensing lines and they are torqued to an
incredibly low torque of 1.2 Newton meters or 11 inch pounds which is just one inch pounds shy of
one foot pound for those of you that speak foot pound rather than Newton meters one foot pound
of torque is too much for the screws so just a light connection is all they're looking for there
okay all the bolts and screws are in just need to torque them now let's see it was 49
on the bolts and 11 on the screws alright this torque wrench right here goes to or
goes from zero to thirty inch-pounds so we'll do the screws first at the 11 inch-pounds I
may have exceeded that just putting them in with a screwdriver let's find out I
think I've got the wrong tip alright let's try those screws again number one Phillips
11 so it was a little more than my screwdriver did but I just put them in real light okay all
the screws are tightened to the monstrous 11 foot-pounds or inch-pounds 1.2 Newton meters
all right now the bolts for the positive and negative connections are at 5.5 Newton
meters or 45 or 49 inch-pounds so I'll switch to a different torque wrench because that one
only goes to 30 so this one goes to 75 so I'll sit it on set the pointer on 49
or five-and-a-half Newton-meters right in the middle there and then we'll snug all these up
okay all the bolts are tightened all right let's take some voltage
measurements if we go from the overall
battery negative right here with our meter on DC volts to the stack positive over here we get
ninety four point two volts I told you before that anything under a hundred volts you're not required
to wear PPE for by the Department of Energy or the National Fire Protection Association
but the most of automobile manufacturers wants you to wear it at 50 volts I just wanted to show
you if I touch the 94 volts right here it does nothing to me but that's with my body and skin
resistance and so on it's not something I'd recommend that you do I just wanted to show
you that it's it's it's a safe voltage in most conditions all right so let's put these or no
let's take some more measurements so if we go from I'll see this was battery negative
right here if we just go over to the first bus bar there's our seven point eight volts
for that module we go over to the second bus bar now they added together at fifteen
point six eight if we come back to the third twenty three volts go over here to the fourth
31:39
fifty-four oh I skipped one forty-seven
in 54 60 to 70 78 86 and finally 94 so it's just in series we add 7 point 5 to 7 point
8 bullets apiece what we say this was per volt per module 7 point 8 volts instead of
7 point 5 so it's slightly charged more than the nominal voltage but not fully charged at
the 4 point 2 volts each by the way if it was fully charged at 4.2 volts each 4.2 percent of
cells in each module so that's 8 point 4 volts per module times the 48 modules that there are
so that's fully charged this would be 403 point 2 volts and if it was 3 point 2 volts per cell
it fully discharged times two parallel cells per module that's 6 point 4 volts times 48 modules
307 volts 307 point 2 and fully discharged but you normally don't want to go to fully
charged or fully discharged you want to keep it between the 20% and 80% unless you've on a
road trip or just have no choice but to keep driving all right well let's get this let's
get these covers on got an arrow pointing to the front this is the front of the vehicle over here
just like that
one down below and one more over here
okay so on this module here we have the module negative and the module positive these 290 volts
between them this happens to also be the overall battery negative right there so once again this
is our right hand module our left hand module is just like it back here and then our rear module
I want to look at next just a little bit okay right here on the end of the rear stack of 24
modules is the lithium ion battery controller this is a computer that monitors this individuals cell
voltages of all 48 modules it has electrical connections on the side and along the bottom
according to the service information and the training guide that eye guides that I downloaded
it monitors the cell voltages individual cell pair voltages so two for each module and the
temperature sensors that it has I believe this has four temperature sensors on this early model
and later on they added more temperature sensors it controls the cell pair voltage variation so
any difference between the two parallel cells two sets of parallel cells inside the module it tries
to balance those out it also tries to prevent over charging discharging and overheating of the
battery by controlling how much current can come in and go out while driving while charging and so
on so now that I've swung this around we can see this rear stack of 24 modules at 7.5 volts each
that gives us 180 volts between this overall battery positive terminal right here and the
other end of the battery module for module 24 right over here 180 volts and so this one when
we go to hookup wires to it we'll have to wear our personal protective equipment but even though it's
a 180 volts total if I come in with the multimeter and we just start here at overall battery positive
guess I better use the positive terminal and we come down to the negative terminal
down here it's just seven point eight volts for the one module if I pick a point halfway
across over here let's see where we are right here there are 102 volts right there
yeah it's come over a little bit more 133 and all the way to the other end
188 point 3 volts so each individual module adds another seven and a half volts alright so this has
the same type of bus bar and voltage sensing system that we saw on that right hand stack
assembly over there there's nothing special about this as far as the busbars are concerned it just
puts every other module or every module in series with the next one oh let's see there's some covers
that go on this so as an up arrow up and up and these all appear to be identical it does tell us
when we're removing these that we take off the two outside ones first and then put on the middle or
then take off the middle one which means we'll put on the center one first let's see up yeah
up right there maybe see if that works out over here yes so now we are ready to put these three
stacks of modules into that empty battery case now that were far from finished because that
just sets the modules in there then we have to connect each module together we have to have a
service plug and a fuse we have to hook up all the internal wire harnesses for monitoring all
of the internal voltages and connect that to the lithium-ion battery control computer right here
this does have a battery heater if you have the cold weather package on the 2011 it came standard
on 2012 and above models I believe unless you live in a well elite for certain geographical
regions of the of the world alright now each of these modules to lift them up and put them in
the the battery housing or they're very heavy so there's there's a hole right here there's a
hole right here in these end brackets so there are four holes on each of these end brackets
for these modules that will use a engine crane to come in and lift those up and set them down
in to the battery housing lower housing itself so now let me reposition the the housing and
the get the crane over here and we'll get these hooked up and set in okay I brought our engine
crane in I've got our crane scale turned on so we can see how much each of these module stacks
way and so we'll just get these straps hooked up here with these hooks these straps are rated for
3,200 pounds the way I have them looped through the hook here and we're way less than that here
so there's no danger of straps giving away all right well Center the crane the best we can
take the slack out of the strap there we go mr. crane forward just a bit and lift it up
straighten this out just a little bit there we go all right it looks like we're reading
119 note 120 120 pounds on the right-hand module stack so now
we'll just move this over to the battery tray and set it
in on the right-hand side with this in the front the tall section in the front
so this stack is going to go right here except this is the front and that's the
front I need to now I will just spin the load around bring in the crane
right there start there bring it down slowly there are some guide studs down
inside of the housing here that will line that up with once it gets down and
just like that all right let's get this table out
of the way for a moment let's come in and get the left-hand stack next okay
I'll Center the table a little better under the crane the scale on this one is reading
one hundred nineteen point five thousands so let's put that in the battery housing next
just like that
all right now we're ready for that rear stack okay we've got our rear stack sitting right
here if we look at the crane scale we are at 229 229 pounds and we were 120 pounds a piece
on the side stacks so 120 plus 120 is 240 plus another 230 gives us 470 pounds of cell stacks
now according to the specifications from the Nissan service information this entire battery
pack and housing and everything weigh 660 pounds so there's another 190 pounds of bottom tray
upper cover and internal pieces that have to go together now I did measure the bottom tray
to see how much it weighed if you look at this photograph here you can see that also underneath
the bottom tray there is a center of gravity mark it looks like a almost a little star type compass
that you want to position your lifting table underneath because the rear stack of course
weighs more than the front two stacks Earth's in its position towards the back of the vehicle
as well so you don't want the center your table under the center of the battery as you lower one
of these batteries down out of the car you want to Center it under that center of gravity mark
alright well let's set this in the battery tray and move on alright let's bring it down there's
a couple of alignment studs on the back here to line it up alright ok we finally have the
right hand stack the left hand stack and the rear stack installed in the bat lower battery tray now
we need to install all of the wiring that connects these cell stacks together to combine and and give
us in a big series circuit the three hundred and sixty volts we have to have a way to connect to
the outside of the battery and run cables to the inverter assembly that drives the electric motor
we have temperature sensors we have to install we have battery heaters we have to install we have
the junction block with the positive negative and pre charged contactor pre charge resistor we have
some structural supports that go in here and all of that is coming up next alright before we start
putting the wire harnesses in and connecting all these module stacks together we have to
bolt down these module stacks to the housing so there are both nuts and bolts that need to be
put on to hold each of these stacks to the lower battery tray so let me get those installed next
you
okay I've got all the nuts and bolts started I'm going to use my electric drive gun here to
slowly run them down to where they bought them and then we'll come back around with a torque wrench
okay all the big studs and the bolts they'll hold down these battery stacks are torqued
to 9.6 Newton meters or 85 inch-pounds not foot-pounds so we'll get these torque next
okay I've got all the module stacks bolted down with their numerous bolts and studs and ready to
move on to the battery heater system but there are some brackets that I have to install on the rear
battery stack there in order to make room for the battery stack heaters and the wire harness
retainers and so on so let me get these brackets installed next so there are four vertical brackets
that use the dark-colored nuts to be held in place and they go every other set of
studs if I would have been thinking I would have put these brackets on
first before putting the battery stack down in the battery tray but I forgot
all the brackets all the rest of the brackets that go on here and the ones I just installed
have the same tightening torque of 9.6 Newton meters or 85 inch-pounds we have to tighten or
torque these brackets first before we put on the next brackets all right the next bracket
we put on is to support the battery heaters on the rear stack that go over the top on both the
driver side and the passenger side it is retained with the light-colored nuts rather than the dark
ones okay now we have battery heaters to install there are six eight of these battery heaters six
of these smaller ones for the two side stacks the left stack and the right stack and then
two great big ones for the rear stack for a total of eight heaters so this is the right
side stack heater notice it has orange wires going to it it is fed power off of the high
voltage battery itself so these are high voltage heaters so we'll set those in place where they go
each of these heaters has a stud that we have to put a nut on to hold it down so that was the
front heater this next one here is the center heater heater number three just like that then
we have side stack heaters for the very back of these side stacks just like that and like
that and then for the rear battery stack we have the left and right upper heaters a kind
of an interesting thing about the operation of these heaters in the instructor guide and
service information that I've have access to it it says that they don't turn on until a negative
17 Celsius or 1.4 degrees Fahrenheit and the purpose of these is to keep the electrolyte in
those cell pouches from freezing so they turn on at one point four degrees Fahrenheit and turn off
at fourteen degrees Fahrenheit so they're not going to feel warm to human touch when they're
on but their job is to just keep that electrolyte from freezing and it uses power from the battery
itself and it does not need to be plugged in for this to work this will continue working drawing
power from the battery it's my understanding until the battery state of charge gets down
to thirty percent and then at that point it shuts the heaters off to preserve what little
life there is of the battery left and then if it still gets too cold it's just going to freeze and
damage the battery so you should always keep your car plugged in if possible especially in
cold weather so it's just a resistive element type heater we can't really see the resistive
elements we just have this aluminum plate that the elements are sandwiched between so let's
let's take one of these apart and take a look at it so it's just got a couple of wire ties
holding the harness in place so we'll lift that harness up out of there just like that so it has
two tabs that have to be pressed and released in order for the element to slide out it's almost
a three handed operation there we go okay so it just slides over a little bit and then lifts out
okay looking at this heater element here it looks like we have a power wire that comes in and feeds
the outside one the middle one and the other outside one with battery positive high voltage
battery positive it looks like the resistive elements all connect together underneath down
here electrically and then the return-path are the two wires right here that go back to
battery negative an interesting little heater element assembly so the whole element assembly
just fits on top of the rear battery stack as I said before we have one for the right-hand side
like that and this other one that we took apart for the left-hand side okay let's
put this heater element back in the housing just bring it in and slide it forward until
it stops and then our harness get it back where it's supposed to go just like that
so we will set this right over here on its installation studs all of these heaters that
I just installed all eight of them are held down with the light colored 10 millimeter
head nuts we'll get those installed and torque to the same 9.6 Newton meters or 85 inch pounds
okay we've got all the battery heaters bolted down and torqued and now the next thing to do
is bring in the battery heater wire harness okay this is our battery heater wiring harness
and it makes a connection of course with every battery heater it makes a connection
up front here where the junction block with the contactors goes because that's where it
receives its power after the contactors are enabled and then we have a controller that
is going to control the heater that plugs in also so let's get this set in place the power
source harness side that there's a left and right side here has to go on the driver's side
so I've plugged in our wire harness from the two rear heaters into their brackets and now we'll
bring in the heater harness and then the supply power for the left and right rear stack heaters
there we go and then as I said we have a left-hand side heater harness and the
right-hand side heater harness these have to go in underneath everything else all the other
brackets and other harnesses that we put in here it's clear down to the very bottom so I'll have
to lift up other harnesses and tuck it down in it has some little Clips harness clips that hold
it in place another one and we supply power to the front heater with this connector power to
the other front heater with this connector get our harness clips into their brackets
we have right-hand rear power here to the right hand stack and rear power to the left
hand stack and we've got the center heater with its connector plugs into a bracket clip
on the driver's side left hand side and then the center heater connector on the right hand side
just like that and plugs into a bracket
down below there we go alright so now the only loose harnesses we have are
the two control harnesses and our voltage sensing harnesses and the power feed for
the battery heater okay now that we've got the battery heaters and the heater harnesses
all installed there's a big structural support member that goes left to right
I believe to protect the battery in the event of a side collision so this goes in
after the wire harness for the battery heater otherwise you won't be able to get it installed
two big studs with nuts to be installed on the outside edge
and four bolts that supported in the middle here
all right well torque these Center bolts to the same 9.6 Newton meters okay well tighten these
two outside nuts on the studs to 25 foot-pounds or 33.9 Newton meters okay before we can install
the rest of the wire harness there are some additional brackets that need to be installed
here let's get those in place this front one here that I'm installing is for retaining the
hybrid or is for retaining the junction block with the contactors in it so we'll set that
down there then we've got another bracket for the rear back here that helps hold wire
harnesses in place get these bolts torqued to the same 9.6 Newton meters okay next we have
one two three four temperature sensors for this entire battery pack two of them go in
the rear stack and then one on each of the left and right stacks so let's get those installed
this one measures the temperature of module 44 this rear one measures the
temperature of module 1 the very end 1 and module 12 one right in the middle
module 1 and then module 12 and then just a bunch of clips to hold the harness as we run it all the
way over to the end over here where the battery computer is going to plug in and then the last
temperature sensor is for module 27 which is this bottom one here on the driver's side Center
a couple of brackets alright we have one more part to install now this is the battery heater
controller has a contactor a relay as they call it here and a little computer processing unit it has
an external interface connection right here with the lithium-ion battery controller and then these
two brown connectors right here one of them is the input from the power from the contactors up front
and the other one is the output to all of the heater modules themselves so this sits right here
plug in our two brown harnesses here and then it has three nuts that hold it in place making
sure that we're not pinching any other harnesses underneath it all right we'll get those torqued in
place okay the next thing to install is called the battery junction block and if I take the
cover off of the battery junction block you can see in here that it has a positive contactor
right here a negative contactor right there it has a pre charged contactor right there it
has a pre charge resistor underneath it with the resistance of 30 ohms we have our heater battery
heater power that comes off of this side we have a current sensor right here that is used by the
battery controller for monitoring how much currents going in and out and then we have a
low voltage connection right here connected to the computer that is used to control all three
of these contactors and measure the amount of current through this current sensor here and if
you're not familiar with a battery junction block I've covered this in many of my other videos but
basically what we have on our on the end of the junction block here is we have I'll make sure I
got the polarity right overall battery positive from this entire battery here will connect right
here overall battery negative will connect right here now this positive right here when we engage
the positive contactor will be connected to this output terminal over here so right now
there is no connection between this side and this side no connection but if we turn on that
positive contactor it will connect this side to this side this is the output that goes on under
your car in the big high-voltage orange cables up to your inverter assembly that is and your
DC to DC converter and air conditioning driver and everything else and but more importantly to
the electric motor to make the vehicle move on the negative side the negative contactor
right here when it turns on connects battery negative on the input side to battery negative
on the output side for the inverter as well so just it's just bigger looks a little different
than other battery junction blocks but it has the exact same parts it works the same way and so we
will install that here next in preparation for the high voltage harnesses to be connected so there
are just four nuts to hold this down on studs I'll get these torque to the same torque as the other
bolts the 9.6 Newton meters all right with the Junction block installed I can now connect the
high-voltage power connection from the junction block to the battery heater controller but none
of that is live at the moment because there's really no power here at the junction block okay
finally the main harness can be installed this end of the main harness connects to the lithium-ion
battery compute or controller and the other end connects to all of the voltage sensing lines on
the battery module if we remember there's that little Phillips head screw in the middle of the
to the the battery positive and the battery negative terminals on each module these wires
connect to that screw and to one of the positive or the negative terminals on that same module so
that it can measure both voltages so when we start plugging these in that's when we're plugging in
high voltage connections because those are live connected to the battery right now so I'll have
to have my personal protective equipment gloves on at that point this black portion of the harness is
the low voltage harness and it connects to all of the temperature sensors the heater controller
and the junction block up front that we just connected or installed and then it connects to
an external harness that will go out the front of the battery itself so let's get this in installed
next alright we'll plug in our temperature sensors on the rear here anyway or in the middle
rear temperature sensor harness low voltage alright there's one more component I forgot that
I could install without high voltage gloves on it at the moment and this is the front
electrical connector there's two pins right here for the battery positive and negative positive is
this terminal negative is this terminal once power is transferred through the contactor
contactors and this is the low voltage harness connector that connects to this harness right
here this little tiny two terminal connector right here is called the interlock circuit
and it connects right here on this harness the interlock circuit will detect when someone has
unplugged the electrical connector right here without powering down the system properly and
if it detects that then it automatically shuts off the high voltage contactors the
positive and negative contactors in the junction block to remove power so that you don't get DC
arcing as you are unplugging the connector in a possibly live circuit which is a really bad
and dangerous thing to do so now this is going to stick through the front so I just installed this
and now we've got a ground strap right there that will install and I'm missing four nuts
alright as you can see there are four studs right here that are missing nuts and I'm usually pretty
good at keeping things organized I couldn't find the nuts and so one thing that I always do before
disassembling anything is to photograph it take a lots of photographs and it turns out when this
battery arrived those nuts were missing they just weren't installed so I've got some other
nuts that'll do the trick but they're not the correct and not for the this application but
it's the same thread so I'll get those installed we've got to install the two bolts that connect
to the contactor output to this connector here now and we can get everything torqued
now we can connect this low voltage harness to the output connection finally that was a rough
one and then our interlock circuit connector right there all right and then our low voltage
control harness from the battery computer to the contactor assembly to control those all
right I'm ready to get my high voltage linemen gloves on with the leather outer covering this
box of gloves I purchased earlier this year it has a five of nineteen date on it and this is 12
of 19 and if you've heard there's a six month expiration that's true but it's only from the
day that you opened them and first used them so we actually received them on eight twenty nine
of nineteen and according to OSHA they can sit unused in their box for up to one year
before opening them and then you still have six months after that so these are brand new
Salisbury linemen gloves normally there's an opening you can just slide them right out of there
but they seem to be welding the plastic now to get the or to keep them in in good shape in storage so
very carefully so I don't cut the the gloves or myself I'm going to open that bag it's kind of
interesting in the Nissan's service information and the training material in particular they only
showed photographs of technicians using these lineman gloves with no leather outer protectors
well that's that's against OSHA regulations here in the United States I don't know what
the regulations are in Japan if that's where they developed the training but these gloves
can be damaged quite easily and I have a separate video on personal protective equipment and how to
check high-voltage gloves and so on but you just want to inspect them blow them up look look and
listen for leaks before you and stuff before you put these on your hands and basically put
your life in your own hands every day so I will get these checked and get them on now according
to OSHA there's only one exception where you can use the gloves just by themselves and that is if
wearing the leather outer protectors makes it too hard to get in and manipulate small parts
but it also says once you do that these gloves are no good you have to either replace them or
send them out to be recertified not just you doing an inspection but an actual electrical insulation
recertification so that's an expensive decision to make so always wear your outer leather protectors
as you work on high voltage circuits by the way high voltage in the outside of the automotive
world is not 400 volts this is considered low voltage these these gloves are rated for 1000
volts and somebody put a sticker over it but they actually say low voltage right on the
the box itself so anything less than 1000 volts but remember I said according to the National
Highway Traffic Safety Administration Federal Motor Vehicle standard 305 I believe states
that high voltage in the automotive world is anything higher than 60 volts DC and 30 volts
ac alright well we've talked about that already we are ready to start connecting all of our high
voltage sensing lines and then we'll get out the great big battery high voltage battery cables that
connect the individual stacks to each other so let's get these voltage sensing lines connected
so this harness here is the voltage sensing lines for the 24 rear modules and then that goes right
over to the the computer this harness here that I'm going to plug in next is the voltage sensing
lines for the right-hand stack and then this other harness here is the voltage sensing lines for the
left-hand stack so all of those are connected now so now we have two great big orange cables
these two cables are what connect the overall battery positive on the right
rear of the rear stack they're all the way up to our contactor assembly and what connects
the overall battery negative to the contactor assembly as well through the service disconnect
lever that we still have to install here so let's get these two cables installed
and then as you can see this cable will come all the way forward and connect to
the input of our contactor assembly here our junk Junction block but we have to install
the service disconnect lever because it's got some harness hold down clips in there
that we need to connect as well so now we'll install this big heavy cable here this will go
from module 24 at the left rear to the service disconnect lever that we have to install next
it is now time to bring in our service disconnect connector and lever right here
the service disconnect connector has two terminals underneath it right here these
two and when the service lever is installed it connects this side to this side or just connects
the two together so we are going to use this to connect to that last cable we just installed
and then another one to connect to the battery and this when this lever is removed creates an
open circuit just like it is right now inside of the battery which reduces the overall voltage of
the sections instead of it being 360 volts at the contactors it would be zero but it really
divides it into let's see it would be a 100 or no 270 volts section and a 90 volts section is
what it would divide it into alright the service disconnect lever itself right here
I've opened it up which you're not supposed to do and it has a 225 amp 450 volt inside of
it so here's the bottom view and so this goes right in here except I may have it backwards
just clips in place just like that the two little tiny terminals right there that's the
another interlocked circuit so if you disconnected this before you were supposed to the interlock
circuit would disconnect first and it would kill the power to the contactors which would prevent
arcing as you move this which is why you must wear high voltage gloves when you remove this
just in case there's live circuit DC arcing in a live circuit is is frightening there's videos
all over YouTube of DC arcing take a look at it it'll make you want to wear your gloves alright
so I'm going to install the connector but not the service lever until we're done with everything
okay when installing this service disconnect lever connector we have a bus bar that's going
to go from the connector over to module 25 the big harness the big cable that we just
installed the shorter one comes from module 24 so remember everything is in series so we have
module 24 coming in here it connects to module 25 it's just a big series circuit but when the
service disconnect lever is removed the this series circuit is opened alright let's see if
we can get this cable connected now bring that in underneath put the rub rubber cover back over it
there we go and now we can set this straight down and into and over the heater get our connection
made here at module 25 looks like we did so now if we can install the nuts that hold that
down and the nut for the connection on module 25 I forgot to hook up the interlock circuit
to the bottom of the connector there so we gotta take that cover her that
bracket or take the bracket bolts out just long enough to plug that back in
okay let's take that out and plug that interlock circuit harness into the service disconnect lever
connector so we'll just lift this back up this little white connector right here it's gotta
go in and plug in right there okay now we can put this back in if you leave that interlock
connector disconnected like I accidentally did there the vehicle would never power up
because it would immediately see there's an open interlocked circuit which should
always be closed or a big series circuit and it would never enable the contactors
to close so there'd never be any power to the inverter to make the vehicle move so it's a
very critical circuit okay we're just about done we have two more bus bars to install to
put more battery modules in series with each other to increase the voltage and to connect
the overall battery negative terminal over here to our contactor assembly here
so I've got one bus bar that connects module 36 to module 37 36 is right here on the right
so this is going to go across here let me get this big cable from battery positive down on
there we go okay so 36 to 37 here too right there and then module 48
to battery negative so overall battery negative looks like I better put it
on first all right it looks like this bus bar should have gone on before the
contactors would have made it a lot easier this is not impossible but it's less than ideal there
we go okay so there's our negative terminal bus bar connected so now we can connect the rest of
these or put the nuts on the rest of the bus bars and get module 36 here connected to module 37
let's get those torqued get these back ones here as well and one more to torque right over there
module 24 okay the last internal piece to install is the lithium-ion battery controller computer
and he has all the electrical connections for the voltage sensing circuits the temperature
sensor sensing circuits the contactors and the interlock circuits and external communication
now the service information warns us that we should always disconnect this first and install
it last otherwise damage to the computer can occur so we connect the high-voltage
lines first and then the low-voltage lines it has four bolts that hold it in place
two bolts in the back okay these are only torque to 5.5 Newton meters and
then finally the last two electrical connectors the low-voltage ones for the
lithium-ion battery controller and there we go alright the last internal piece to install
except I'm not going to install it yet because I need it off for demonstrations in my classroom in
my classes is the junction block cover that covers up the contactors and the electrical
connections and and so on but I want to show you the function of the service disconnect
lever and the contactors themselves and so let me grab a multimeter okay just a quick
word about multimeters they need to be rated category 3 1000 volt for this type of work
and a good quality meter a good name-brand meter who has had their meter tested and certified by
some sort of service certification organization such as underwriters laboratory or the Canadian
standards Association or Intertek or whomever to make sure that this meter is following all
of the insulating and personal protective requirements laid out by the International
Electrotechnical Committee and that's for your safety meter leads wear out over time the real
flexible ones the the strands can break and you need to make sure that your meter is clean and
in good shape you also need to verify that your meter is capable of reading accurately
before you bet your life on some sort of a reading that your or measurement you're going to take on
the battery so for example on these these front two terminals right here it's showing zero volts
but am I sure that the meter is even working am I sure that the leads are in good shape so the best
thing you can do is test it on another battery just a 12 volt battery 9-volt battery whatever
fluke does sell what's called a proving unit I've got one of these right here as part number
pr8062403 in this proving unit but looking at the screen of my fluke 87 here we go 236 volts
so we know that the meter is capable of reading a high voltage not just nine volts not just 12
volts and and as I said this can do AC voltage as well but we're dealing with DC right here on
this battery so I'm going to switch meter leads or ends of the meter leads to alligator clips
and even the tips and ends need to be certified I have a separate class where we talk about that
so I've got alligator clips and I'm going to put the red clip on the overall battery
positive connection right here at the contactor so right there and then the black alligator clip and
meter lead to the overall battery negative side right there alright as you can see the meter is
reading well 320 millivolts thousandths of a volt so this is less than 1 volt so now I'm going to
come in with the service disconnect lever and plug it into the connector and now we should
get the 360 or whatever volts proving that the service disconnect lever fuse is good and that
it's an open circuit at the moment so here we go it's plugged in we are now reading 376 point
6 volts at the input side of the contactor with the service plug installed as you can see there
alright now I'm going to move these meter leads to the output side of the contactor and I want
you to notice that now the meter now the meter shows pretty much 0-3 millivolts no power no
voltage and that proves that the contactors are open they're not allowing that 370 whatever volts
to be present on the output lines which means the voltage here on the front of the battery is also
0 so the contactors do a good job of opening the high voltage circuit there when we do service work
or on the vehicle and we want to disable all of that then we just remove this service plug lever
when told to buy the appropriate service procedure but you don't always do that there's there's times
that you'll want that plugged in for Diagnostics but the important thing to know is that when you
do remove that it opens circuits the inside of the battery and there will be no or there should be no
power on this output but you should always use a qualified tested multimeter to verify that there's
no power there before you disconnect or any other components or go inside and assume that something
is D powered without checking it first I'm going to remove the service plug lever push on a little
tab rock up and pull alright just a couple more things and we're finished I want to call you to
your attention the seal right here around the outer edge of the lower battery tray this seal
on the first versions the first version 2011 and 12 of the Nissan Leaf it was designed to with the
upper cover put on keep out moisture and dirt dust whatever and it needs to be checked to make sure
that it is sealed properly so right here on the front of the battery is an air leak check plug and
what you do is you take this plug out this plug has a gasket on it a copper gasket just like a
oil drain plug or whatever transmission drain plug come on these gloves are slowing me down
okay so there is the air leak check plugged and there's a special service tool that you screw into
there with the cover on and all the bolts torqued down there's a proper tightening sequence for that
upper cover and then you connect compressed air to it through a special low pressure regulator that
limits the maximum pressure to two kiloPascals which is the same as 0.23 psi pounds per square
inch extremely small amounts of pressure and so you're supposed to pressurize it then block off
the air pressure and it should not drop below zero point two psi if it does then you've got a
leak somewhere and you need to go double-check your gasket and so on on the 2013 later models
that got rid of this gasket and went to a urethane adhesive that you have to cut to
remove the upper cover and then clean it all up and reseal it when you go back together but all
electric vehicle batteries that I've seen that are mounted under the vehicle or outside of the
passenger compartment have some sort of a leak check procedure the General Motors products pump
evaporative emission testers smoke in and you look for a smoke leaking out and then you flush
it all out with nitrogen when you're done I don't know what Tesla has on theirs because
it's it's not a user serviceable battery but I'm sure they have some sort of a leak check
procedure as well just to make sure that the entire battery is sealed you it if you don't
keep it sealed then water and dust and everything else will get in which can cause electrical short
circuits and malfunction computers and all kinds of problems you don't want to have inside of a
battery so that one of the last things you do is make sure that it holds pressure verifying
that it is properly sealed all right this has been a really long video a big long service
procedure of putting one of these back together that almost anybody can take one apart big deal
just take the bolts out and start pulling and enterin and so on but putting it back
together and having at work when you're done is a different story and it's it's critical that
you follow the proper service information and torque bolts especially the electrical
connection bus bar and and cable bolts so that we don't get any poor connections which end up
causing unwanted resistance and unwanted to eat melded connections possible fires and so on all
right well once again I'd like to thank Green Tech auto hybrid batteries for letting us have
them play with this battery here this year greatly appreciate that I appreciate you as
viewers in watching and supporting this channel thank you for watching and have a good day
you