there is a lot of hype about tesla new 4680 format of cells but the real product that
i think deserves all the hype is byd blade battery the new blade battery was developed
by thin dream's battery an independent subsidiary of chinese automaker byd
which is also a major supplier to other automakers in april byd announced that all of its future
electric vehicles will use new blade battery the proprietary blade battery design resembles a sword
a saw plate with positive and negative terminals at each end also saw blade can easily be flexed
from side to side it's rigid when trying to bend it up and down it's the same concept that makes
individual blade battery cells act as a structural support inside the battery pack once installed
in a battery pack honeycomb structural panels provide sufficient support to the battery each
long blade battery acts as a support beam adding strength to the entire pack according to byd
the blade battery was also designed to maximize the use of available space within the battery pack
byd sets that the blade battery offers higher space utilization than any conventional av battery
each blade is 96 centimeters long 9 centimeters tall and 1.35 centimeters wide single cells
arranged together in array and then insert it into a battery pack the design is also known
cell-to-cell pack technology eliminates having to use individual battery modules inside the pack
that each require a separate thermal management system and electronics with this configuration
use of available space is increased over 50 percent compared to conventional lithium-ion
phosphate battery which gives batteries a higher energy density as more cells can be fitted the
other concern the blade battery addresses is safety one of the biggest problems hindering the
development of the av market is the combustion and explosion of the lithium-ion batteries electric
vehicle from tesla hyundai general motors and neo have all experienced battery fires from
overheating but as av adoption ticks upwards the risk of battery fire only increases unless
of course av batteries can be made safer why lfp battery is so much safer well let's have a
look at the first factor lfp chemistry has so much higher decomposition temperature and releases as a
result so much less heat than nmc or any other conventional battery currently in use second
factor specific to blade battery it has so much larger surface area in comparison to its volume so
it has superior ability to dissipate heat and the last factor is also relevant to geometry in the
prismatic cell the nail goes through many layers and creates multiple short circuits as a result
the thermal runaway is more likely to occur in a blade battery which is very long and thin the nail
goes through very few layers and creates a minimum number of shirt circuits one of the disadvantages
of lfp chemistry was fairly low gravimetric energy density after all the theoretical capacity of lfp
is only 170 amp hours per kilogram which is much lower that nmc which is 275
amp hours per kilogram the state-of-the-art lfp cells in the market can reach 160 165
amp hours per kilogram which is bordering towards electrochemistry limitation as a
result the overall energy density of lfp pack is much lower than all of that of the comparable nmc
battery pack byd have decided that engineering in park design could move forward the battery market
even if the cell advances are sluggish due to the electrochemical limits or their lfp according
to published byd patents the cell unit of the blade is designed based on prismatic form factor
unlike a traditional prismatic cell however the lens of the blade battery is extremely long
while the depth and height are relatively short as a result the shape of the cell unit is like
a blade the lens of the blade is adjustable from 600 millimeters to 2500 millimeters the final size
of the blade in the blade battery is not fixed the three-dimensional parameters lengths depth
and height are all tunable with the range of any given parameters the cost of lfp battery pack is
undeniably lower than nmc this is the reason most electric buses in the market use lfp batteries and
early evs in china are equipped with lfp batteries despite the shorter operation ranges with the help
of the blade battery design the cost of the battery pack can be decreased by additional 20
compared with conventional lfp battery packs the cost is claimed to be less than 85 dollars per
kilowatt hour which is lower than estimated cost of the latest lfp pack from cattle which they
offer for tesla which is about 100 dollars per kilowatt hour this is the cost enable the pack to
be more competitive under current policy in china the current policy dictate that lfp systems will
get fewer subsidies due to the low energy density but the blade battery can still achieve 140 watt
hours per kilogram which allows to receive the same subsidies as most other type of batteries
according to latest news the entire eight gigawatt hours of yearly capacity of the blade battery
factory in chongqing will has been reserved for bid and their clients a new report from research
says that the project price of the battery packs keeps dropping and the price of the battery packs
will drop below 100 per kilowatt hour by 2024 obviously BYD has achieved this target in 2020.
thanks to upgraded battery management system and other support systems as well as quality control
the blade battery can have prolonged cycle life of 1.2 million kilometers or 0.75 million miles
over eight years lfp batteries can reach 2000 cycles which is sufficient for power batteries
in the lab tests lfp batteries do not begin to fade significantly until after 3500 cycles and byd
claims 3000 cycles for its blade battery though the blade battery is expected to have longer
lifetime than tenery batteries about 1000 to 1500 cycles that are currently used on the market
after increasing the space utilization the volumetric energy density of the blade
battery is the highest of the lfp family and it's comparable to some nmc batteries
byd may create a new market between traditional lfp and nmc nca making lfps more attractive