Why cars use lead-acid batteries, can't you change lithium batteries?

Why do cars use lead-acid batteries and not lithium batteries?

Why do cars use lead-acid batteries instead of higher energy density lithium batteries? The term car battery has received more attention in electric cars, but the battery in electric cars refers to power batteries, mainly two kinds of lithium-ion batteries and lithium iron phosphate batteries, while ordinary fuel cars also have batteries, namely storage batteries.

Usually it's a lead-acid battery, and in fact, not all batteries in non-pure electric vehicles are lead-acid; BYD's DM-i hybrid is not a pure electric vehicle, but it has a lithium iron phosphate battery, and except for BYD, the batteries in all other known non-pure electric vehicles are lead-acid. So the question is, why don't the batteries in fuel vehicles use lithium-ion batteries, which have a much higher energy density? Drivers who think that the frequency of vehicle use and battery replacement increases when the vehicle is turned off have thought about this, but they also wonder why "no" cars use lithium-ion batteries instead of lead-acid batteries.

In fact, such a statement is too absolute, in fact, many electric cars use 12V battery are lithium batteries, plug-in hybrids are also the use of lithium iron 12V batteries, there is no such thing, the car companies will choose which kind of batteries, depends entirely on the design and manufacturing costs of investment planning, but also depends on the car company's "environmental awareness ". Lead-acid batteries have good fatigue and high-temperature resistance, while lithium batteries are more fragile. Li-ion battery packs are usually equipped with a BMS protection board, which can accurately control the state of each cell in the battery pack to ensure that the lithium batteries are not overloaded, e.g., lithium batteries made of manganese-based materials.

If used continuously for 2 hours at a high temperature above 60°, irreversible degradation may occur; lead-acid batteries have better transient explosiveness, and most of the transient currents of the start-up system are above 200A, and the performance of Li-ion batteries will decline rapidly under high rate discharge, while the maximum discharge rate of lead-acid batteries can be up to 10 times, and the general working rate is 3-5 times. Lithium battery accidents are frequent, news reports about spontaneous combustion of lithium batteries in new energy vehicles and electric vehicles are often reported, so that people stay away from lithium batteries, no one wants to have an unsafe starter battery that is prone to spontaneous combustion, and can use it, but don't want to take the risk of replacing the lithium battery.

Lead-acid batteries are relatively cheap although they have low energy density and are a bit heavy, old lead-acid batteries contain a lot of lead, and old lead-acid batteries are recycled at about four dollars a pound to 12V65Ah starter batteries, for example. Replacement of old lead-acid batteries with brand-new lead-acid batteries of well-known brands costs only more than 200 yuan. Compared with lithium batteries, the biggest advantage of lead-acid batteries is safe and cheap, fuel car batteries are starting batteries, a short period of time can provide a few thousand amperes of current, work for five seconds after the battery is no problem, lithium batteries, the biggest problem is unsafe, easy to fire and explode, especially in the engine compartment where the temperature is high.

The risk of fire and explosion is doubled, lithium batteries are also difficult to provide a large current release, lead-acid batteries and generators are directly connected in parallel, that is to say, as long as the vehicle is started, the generator is not a problem, the lead-acid batteries have been in a state of charge, if so, lithium batteries certainly can not stand. For various reasons, ternary lithium batteries are not suitable for ordinary fuel vehicle batteries, batteries with lead-acid batteries is enough. For electric cars, energy density and range are very important.

The indicator, because the ternary lithium battery with higher energy density will become the first choice.