Due to the rapid development of lithium battery technology, which has led to the rise of new energy vehicles, lithium batteries have better performance and lower prices than before. However, many gasoline-powered cars still use bulky lead-acid batteries as starting power sources. Although lead-acid batteries have many advantages, they are still lagging behind compared with lithium batteries. However, why do petrol-driven vehicles still use lead-acid batteries instead of lithium batteries?
First, let’s compare these two batteries:
Advantages of Lithium Batteries
1. The cycle life of lithium batteries can reach 800~1000 times, while the cycle life of lead-acid batteries is less than 500 times, and the service life is shorter than that of lithium batteries.
2. For batteries of the same size, lithium batteries have a larger battery capacity, while lead-acid batteries have limited capacity.
3. Under the exact specification and capacity, the volume of the lithium battery is 2/3 of the volume of the lead-acid battery, and the weight is 1/3 of the lead-acid battery.
4. Lithium batteries can achieve high-current rapid charge and discharge, while lead-acid batteries can not achieve high-current fast charge and discharge.
5. Lithium batteries are environmentally friendly batteries and do not contain toxic and hazardous substances. However, lead-acid batteries contain a large amount of lead acid. If they are disposed of improperly, they will pollute the environment.
Since lithium batteries have so many advantages, why do traditional car batteries still use lead-acid batteries?
Advantages of Lead-acid Batteries
Lead-acid batteries are indeed cheaper than lithium batteries. Is this the root cause? Not necessarily. I think the deep-seated reason why automakers still choose to use lead-acid batteries as starting power source is that the safety, stability and environmental adaptability of lithium batteries are far inferior to lead-acid batteries. The cost of batteries is only a secondary factor.
Although lithium battery manufacturers use professional battery testing equipment to perform a series of safety tests in accordance with UN/DOT 38.3, IEC62133, and other industry safety standards in the process of R&D, design, and production, there is still no guarantee in actual use. Due to the structural characteristics and material properties, lithium batteries can not withstand low temperatures and high temperatures. If installed on the car as a power source for starting and lights, when our car is running for a long time, the engine cabin temperature may be very high and can’t immediately dissipate heat. If a lithium battery can not withstand such a high temperature, there may be an explosion or fire.
Lead-acid batteries can be used normally in low-temperature environments, while the discharge performance of lithium batteries at low temperatures is attenuated. The power consumption of minus 10 degrees Celsius is high-speed. Lead-acid batteries can still easily start the car at minus 50 degrees Celsius, but the lithium battery is problematic. If you own a lithium battery-electric car, you should know this: why in the cold winter, the battery life will be significantly reduced. An electric vehicle that should drive 300km on a full charge runs out of power when it travels 200km in low temperatures.
Lithium batteries must not collide. The car is driving on the road. If there is a car accident and the lithium battery is hit, it may explode or catch fire. Although the safety of the driving device is the first priority, in the event of a major traffic accident, the instantaneous collision force is considerable. In case of a collision or squeeze to puncture the lithium battery, it will cause a short circuit, explosion or fire. This situation is dangerous.
Besides, lithium-ion batteries are prone to form negative current lithium crystals when discharged at high currents. They will break down the diaphragm, causing short circuits and explosions.
In summary, traditional car manufacturers mainly consider which battery to choose from the perspective of battery safety, environmental adaptability, and cost. As a result, most cars now use lead-acid batteries as power sources for starting engines.