Li-ion batteries are the main technology on which the Battery EV vehicle technology hinges as of now. However, though these batteries offer better energy density as compared to Lead-Acid batteries, they are more volatile and prone to catching fire or exploding when damaged or overcharged. This has led to several safety concerns. Also, with the race among the manufacturers to offer maximum range, several high voltage batteries have been developed which if not handled properly may to lead to fires and explosions.
One of the tests to assess the safety of the battery is the nail penetration test which simulates a damage to the battery. In such tests, ternary Li batteries may reach a temperature of 500 degree C and burn violently. Though conventional lithium iron phosphate block battery do not emit flame during such tests, however their surface temperature may reach dangerous temperatures of 200 to 400°C. Such temperatures may lead to other ev components catching fire.
The Chinese battery and EV manufacturer BYD has developed a new technology blade battery. In the blade battery, the singular cells are arranged together in an array and then inserted into a battery pack. Due to its optimized battery pack structure, the space utilization of the battery pack increases by over 50% compared to conventional lithium iron phosphate block batteries. Thus improving the energy density of the battery. Some of the technical advantages of the blade battery are:-
- A high starting temperature for exothermic reactions.
- Slow heat release.
- Low heat generation.
- Ability to not release oxygen during breakdowns or easily catch fire.
During the launch of the battery, BYD demonstrated results from the nail penetration test. During this test, the blade battery did not emit smoke or fire and its surface temperature reached only between 30 and 60 degree C. BYD informed that during the development process, the blade battery underwent several extreme test, the company crushed and bent the batteries. They heated the battery in a furnace ay 300 degree C and over charged the battery to 260%. In none of the test, the blade battery either caught fire or exploded.
BYD has displayed its readiness to share the technology commercially with EV manufacturers. They have also confirmed that the new BYD Han EV would be launched with the Blade Battery.
The Transport Journal 