Engineering:Blade battery

Short description: Battery type for electric vehicles

Blade battery packs showcased at the IAA Summit 2023, Germany

The blade battery is a lithium iron phosphate (LFP) battery for electric vehicles, designed and manufactured by FinDreams Battery, a subsidiary of Chinese manufacturing company BYD.

The blade battery is most commonly a 96 centimetres (37.8 in) long and 9 centimetres (3.5 in) wide single-cell battery with a special design, which can be placed in an array and inserted into a battery pack like a blade. It is made in various lengths and thicknesses. The space utilization of the battery pack is increased by over 50% compared to most conventional lithium iron phosphate block batteries.

The blade battery was officially launched by BYD in 2020. BYD claims that compared with ternary lithium batteries and traditional lithium iron phosphate batteries, the blade battery holds advantages in safety, range, longevity, strength and power.

Safety

BYD claims that, in the nail penetration test, the blade battery emitted no smoke or fire after being penetrated, and its surface temperature reached only 30 to 60 °C (86 to 140 °F). The blade battery also passed other extreme test conditions, such as being crushed and bent, being heated in a furnace to 300 °C (572 °F), and being overcharged by 260%. None of these resulted in a fire or explosion.

BYD claims that "EVs equipped with the blade battery would be far less susceptible to catching fire – even when they are severely damaged."

However, In July 2021, a BYD Han EV with blade batteries was crash-tested in China (car-to-car crash test) versus an Arcfox Alpha-S. At about 48 hours after the test, the BYD Han was producing smoke and allegedly caught on fire. BYD reasoned the fire to be due to the misuse of battery coolant. Specifically, the red coolant used was identified as conductive of electricity, which caused further reaction when the blade battery and wirings were damaged. The standard battery coolant used in the Han is "purple", which is not conductive of electricity. BYD also rendered the testing as "not mainstream, non-authoritative, and not within the industry standard", and wishes for the media to communicate with the company to understand the specification to the car before testing for a more objective and reasonable result.