A flat-pack powertrain? How this Swindon firm makes EV batteries that arrive in crates, ready to be used for new cars:
Continuous power output is 31kW for the smaller pack and 61kW for the larger one, and both are liquid-cooled by a 50:50 mixture of glycol and water.
Technically, they’re straightforward, automotive-standard, lithium ion units measuring 1000mm long and 420mm wide and either 375mm or 615mm high, depending on the capacity. Weight is just 190kg for the smaller pack and 350kg for the larger one, including the integral battery management system and a manual disconnect for servicing or emergencies. The packs are supplied in their own enclosures , which incorporate thermal management and prevent physical damage.
Elsewhere in the battery industry, American firm Nextech’s lithium-sulphur technology has earned the latest safety certification needed for it to be used in production. Nextech says this is the first battery of its type to earn the certifi cation and explains the advantages of its “semisolid-state” chemistry is that it doesn’t have potential for thermal runaway or contain oxygen-producing combustible materials.
Thermal runaway is the potential that any lithium ion battery has to burn uncontrollably if control of it is lost. In production EV batteries today, thermal runaway is prevented by the battery management system, which carefully monitors the charge and discharge state of cells, the load being put on them and the internal temperatures of the battery.
The kind of tests that EV batteries are subjected to should allay the fears of anyone still concerned about their safety. The tests passed by the Nextech battery include altitude tests to ensure it won’t swell and fail at low atmospheric pressure; thermal tests to check its robustness in the face of rapid and extreme temperature changes; and tests of vibration, shock, external short circuit , crush, impact and forced discharge.