Why do electric cars still need to use 12V lead-acid batteries?
Many people think that because electric cars use large lithium batteries, they don't need a 12V lead-acid battery like conventional internal combustion engine vehicles. In reality, modern electric cars all require 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-ion battery pack can generate electricity from 400-800V, but it still needs a conventional 12V lead-acid battery to power devices such as lights, horns, in-car screens, windshield wipers, power seats, and decorative lights.
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Electric cars currently still use 12V batteries to power low-voltage electrical devices. |
In fact, Tesla once unveiled a purely electric model called the Roadster that used entirely high-voltage electricity without needing a 12V lead-acid battery. However, during use, if the vehicle is left unused for 1-2 months or even shorter, the battery pack can be completely damaged and the car may no longer start. The cost of replacing the battery at this point is enormous, up to $40,000. This unnecessary expense could be avoided if the Tesla were equipped with a standard 12V battery, which typically costs a few hundred dollars.
Following that incident, Tesla redesigned its vehicles and incorporated 12V batteries into later models. Many automakers have learned from Tesla's experience and added a 12V battery mounting location to their electric cars.
Currently, 12V power supplies are very common and inexpensive, so they are still equipped in electric cars, helping to minimize production costs. This is why all current electric car models still use 12V lead-acid batteries, while the high-voltage battery system is only used to power the motor and air conditioning system.
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A 12V battery in an electric car helps avoid breakdowns that could drain the owner's wallet. |
Additionally, all ECUs in electric vehicles are powered by low voltage, as are power relays that function to separate power from the high-voltage battery pack and the rest of the vehicle's high-voltage system. This 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 the event of an accident or damage, the 12V battery will help maintain electrical devices such as emergency lights, lighting, communication systems, etc., because the computer will automatically shut down the main battery power to prevent potential fires.
In fact, the automotive industry has now standardized third-party components such as airbags, lights, wiper motors, power windows, power liftgates, mirrors, fans, power steering, power brakes, A/C, etc., all operating on 12V. It is clear that, in the near and distant future, 12V lead-acid batteries will still have a place in the electric vehicle industry.
