BYD: IMPROVED TECHNIQUE FOR SAFER BATTERIES AND MORE RANGE
China's BYD is improving its battery design, creating more efficiently packaged lithium-iron-phosphate batteries that are more stable, less prone to fire and longer-lasting. The new Blade Battery which the company recently introduced has been developed by BYD over the past several years.
Lithium-iron-phosphate (LiFePO4) batteries are more thermally and chemically stable than lithium-ion batteries, but their lower energy density has made lithium-ion a standard. As an answer BYD has developed the Blade Battery, a redesign of the battery pack to utilize space more efficiently. The singular thin, blade-like battery cells are arranged together in an array and then on their edges inserted into a battery pack, creating a strong, space-optimized pack. The idea is the battery cells themselves provide the structural integrity for the pack, eliminating the need for modules and support beams. To complete the pack, BYD sandwiches the battery blades inside upper and lower high-strength panels, inspired by an aluminium honeycomb structure.
The Chinese battery manufacturer states 40% of a typical LiFePO4 battery pack is dedicated to the energy-storing battery cells themselves, while the rest is needed for structural elements. The BYD Blade Battery construction increases the volume available for battery cells up to 60%.
The thermal and chemical stability advantages of LiFePO4 are well-documented, and BYD says that its Blade packs are chemically stable up to temperatures of 500 °C (932 °F), create limited heat during a crash, and don't release oxygen that would accelerate a fire.
According to BYD the Blade battery is also much safer with regard to fire hazard. It has tested the Blade battery by puncturing it with a nail which resulted in no smoke or fire, with surface temperatures only reached 30 to 60°C. Under the same conditions, a ternary lithium battery exceeded 500°C and violently burned, and while a conventional lithium iron phosphate block battery did not openly emit flames or smoke, its surface temperature reached dangerous temperatures of 200 to 400°C. The Blade Battery also passed other extreme test conditions, such as being crushed, bent, being heated in a furnace to 300°C and overcharged by 260%. None of these resulted in a fire or explosion.
BYD has started mass production of the Blade batteries, and it plans to supply third-party companies in addition to using the batteries in its own vehicles. A blade battery with the same size as its 'normal LiFePO4 battery in BYD's new flagship sedan model, Han EV, boasting a cruising range of 605 kilometres.