Why not car batteries use lithium?

At the end of the auto show media day, the hard work for the media people has almost come to an end. Busy for so long, it can be said that every media person who runs the museum feels physically and mentally exhausted, so Mao Mao intends to drive out to Happy and relax.

However, when you sit in the cab and turn the key, you hear the sound of the starter. Immediately after the fur plucked the wiper switch, I saw two rubber rods "slack" on the windshield. Preliminary judgment: the battery is dead.

Plush car has been open for more than four years, to the time of the change of the battery, but the battery in the election and babies had a "new discovery" - the current vehicle storage battery majority also uses lead-acid batteries to valve-regulated Sealed lead-acid batteries are the mainstay.

This is strange, why have you developed a fast lithium battery in recent years, and it has not spread to the battery?

We know that lithium battery with light weight, high energy density, green and so on, in recent years, is widely used in the new energy automotive battery field, but in terms of car battery but rarely seen traces of lithium, which is why ?

First of all, security

The reason why lithium batteries are not popularized in the field of automotive batteries, a big reason is "safety", which has nothing to do with the properties of the lithium battery itself. It is understood that the discharge temperature of the lithium battery is -20 degrees to 60 degrees, the charging temperature is 0 degrees to 45 degrees, and the collision is easy to cause fire and explosion. It can be said that lithium batteries are most afraid of high temperature and low temperature.

The netizen who has opened the hood knows that the temperature of the traditional fuel-fueled engine is very high and that it maintains an optimum operating temperature. In order to maintain this range, the engine block will pass the internal excess heat through various means. Go to the engine compartment and lead to the outside of the car. At this point, the temperature of the engine compartment can be imagined.

What's more, many vehicles are now equipped with turbochargers, and turbocharger is driven by engine exhaust, the temperature is generally 400-500 degrees, such high temperature is undoubtedly a disaster for ordinary lithium batteries.

In addition to temperature, collisional extrusion is unacceptable for lithium batteries. We know that most of the car batteries are placed in the engine compartment of the car. If the lithium battery in the vehicle is in the event of a traffic accident, the lithium battery is squeezed. The result is likely to be a fire or explosion, causing secondary damage and even will become the culprit in the car members.

Second, performance and cost

Generally speaking, the performance of lithium batteries is quite outstanding. Why is it discussing its performance here? Things are far from simple, let's simply count the accounts.

The discharge efficiency of lithium batteries at low temperatures is very low, so if you want to start the vehicle, you need to supply power at the same time 5 times or more. We use the 40 ampere battery used in small cars to calculate the brand's leading Panasonic. The capacity of the Samsung 18650 battery can reach 2900 mAh, and it can reach 40 amp hours in parallel with 14 knots;

On the other hand, if you want to increase the voltage to the start-up battery, at least four groups, that is, 14*4=56 knots, we calculate with a high-capacity battery of 20 yuan, and the lithium battery costs 1120 yuan. In the case of three or four hundred yuan of lead-acid batteries, it is much higher.

In addition, when the car starts, the battery needs to discharge at a current of more than 100 ampere hours. Therefore, the battery must meet at least 5C (5-rate discharge). This can be done easily with lead-acid batteries. Lithium batteries are different, and large currents are directly Affect the life of lithium batteries and increase the cost of use.

In terms of repair rate, due to the current history of production and application of lithium batteries, there are only 20 years of history, and there is still room for improvement in some designs and processes. As a result, the rate of repair of lithium batteries produced by many small and medium-sized manufacturers in China is still high. Lead-acid batteries have developed over the past 100 years, and the technology is relatively mature and stable, and the use is more assured.

Another point is that the lithium battery can't be supplemented with electric energy at the same time as the power amplifier. Once the lithium battery of the power amplifier is replenished, it is likely to spontaneously ignite or explode, which also greatly limits its use in the car.

Written at the end:

The development of domestic new energy vehicles in recent years is in full swing, and the battery field is also developing rapidly. In terms of power batteries, lithium batteries (lithium nickel cobalt manganese oxide batteries, etc.) have been favored by many manufacturers due to their many advantages such as green environmental protection, high energy density and light weight. Introduced into the new energy vehicle, however, the limitations of the safety, performance and cost of the lithium battery have determined that it is still difficult to apply to the fuel vehicle battery. It is expected that the engineers will further improve it and develop and avoid the shortcomings and maximize the maximum performance of the advantages of lithium batteries.