Why do electric cars still have to use 12V lead-acid batteries?
Many people think that electric cars use large lithium batteries so they do not need to use 12V lead-acid batteries like conventional internal combustion engine cars. In fact, today's electric cars all need a 12V power source in addition to the high voltage power from the 400 - 800V lithium battery system.
An electric car with a large lithium battery pack can generate 400 - 800V of electricity but still cannot lack a conventional 12V lead-acid battery to operate devices such as lights, horns, in-car screens, windshield wipers, electric seats, decorative lights...
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Electric cars today still use 12V batteries to "feed" low voltage devices. |
In fact, Tesla once introduced a pure electric car called Roadster that uses all high voltage power without the need for a 12V lead battery. However, during use, if the user "leaves" the car alone, does not use it for 1-2 months or even less, the battery pack on the car can be completely damaged and cannot start anymore. The cost of replacing the battery at this time is very high, up to 40,000 USD. This unnecessary expense can be saved if the Tesla is equipped with a 12V battery that usually costs a few hundred USD.
After the incident, Tesla changed the design and used 12V batteries for later models. Many car manufacturers have learned from Tesla to add 12V battery mounting locations on electric cars.
Devices using 12V power sources are very popular and have low costs, so they are still equipped on electric car models, helping to reduce vehicle production costs to the maximum. This is the reason why all electric car models today still use 12V lead-acid batteries, while the high-voltage battery system is only used to operate the engine and air conditioning system.
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12V battery in electric cars helps avoid incidents that "burn holes in the pocket" of car owners. |
Additionally, all ECUs in electric vehicles are powered by low voltage, as are power relays that separate power from the high-voltage battery pack and the rest of the vehicle's high-voltage system. That separation allows electric vehicles to safely disconnect high voltage from low voltage when the vehicle is not in use or in the event of a collision.
In addition, in case of accident or damage, the 12V battery will help maintain electrical equipment such as emergency lights, lighting, communication systems, etc. because the computer will automatically turn off the main battery to prevent possible fire.
In fact, the current automotive industry has standardized third-party components such as airbags, lights, wiper motors, power windows, power liftgates, mirrors, fans, power steering, power brakes, A/C, etc. to operate on 12V voltage. It can be seen that in the near and far future, 12V lead-acid batteries still have a place in the electric vehicle industry.
