Why use lead-acid batteries instead of lithium batteries for car batteries?

As the starting power source for automobiles, lead-acid batteries have always occupied a dominant position in this field. So some people wonder, can lead-acid batteries be replaced with lithium batteries? In fact, from a technical perspective, it is feasible to design a lithium-ion battery as a starting power source, and some foreign companies have done it. But at present, lead-acid batteries are more suitable for the current situation. At present, most of the vehicle batteries are mainly valve-regulated sealed lead-acid batteries. This is strange. Why hasn't the rapid development of lithium batteries been popularized in storage batteries in recent years? We understand that lithium batteries have been widely used in the field of new energy vehicle power batteries due to their light weight, high energy density, and environmental protection. However, there are very few lithium batteries in car batteries. Why? ? First of all, safety. The reason why lithium batteries have not been popularized in the field of automotive batteries is largely due to 'safetyIt is known that the discharge temperature of lithium batteries is -20 degrees to 60 degrees, and the charging temperature is 0 degrees to 45 degrees, and collisions can easily cause fire and explosion. It can be said that lithium batteries are most afraid of high and low temperatures. Friends who have opened the engine cover know that the temperature of the traditional fuel vehicle engine is very high when it is working, and it is necessary to maintain an optimal operating temperature. In order to maintain this range, the engine block will remove the excess internal heat through various channels. Pass to the engine compartment and lead to the outside of the car. At this time, the temperature of the engine compartment can be imagined. What's more, many vehicles are now equipped with turbochargers, and turbocharging is driven by engine exhaust, and the temperature is generally 400-500 degrees. Such high temperatures are undoubtedly a disaster for ordinary lithium batteries. In addition to temperature, impact compression is also unbearable for lithium batteries. We understand that most car batteries are arranged in the car’s engine compartment, and if the lithium battery of the vehicle is squeezed in a traffic accident, the result is likely to be a fire or explosion, causing secondary injury, or even Will become the culprit to harm the members of the car. Secondly, performance and cost. Generally speaking, the performance of lithium batteries is more outstanding, why is its performance discussed here? Things are far from that simple, let's do a simple calculation with the author. The discharge efficiency of lithium batteries at low temperatures is very low, so if you want to start the vehicle, you need more than 5 times the usual battery pack to supply power at the same time. We use the 40Ah battery commonly used in small cars to calculate, the leading brand in the industry, Panasonic The capacity of Samsung 18650 battery can reach 2900 mAh, and about 14 cells in parallel can reach the capacity of 40 amp; on the other hand, if the voltage is to be raised to the level of the starting battery, at least 4 more groups must be connected in series, that is, 14*4 u003d56 cells, we calculate 20 yuan for a high-capacity battery. Lithium batteries cost 1120 yuan, which is much higher than that of a lead-acid battery that costs 300 to 400 yuan. In addition, when the car starts, the battery needs to be discharged with an instantaneous current of more than 100A. Therefore, the battery must meet at least 5C (5 times rate discharge). This can be easily achieved by lead-acid batteries. Lithium batteries are different. Under high magnification, the performance will drop rapidly and the large current will directly affect the life of the lithium battery and increase the cost of use. Another point is that lithium batteries cannot be supplemented with electric energy while being charged and discharged. Once the charged and discharged lithium batteries are supplemented with electric energy, they are likely to ignite or explode. This also greatly limits its use in automobiles. If the lithium battery safely escapes the 'torture' of the high temperature in summer and low temperature in winter, but if you need to use the car frequently, the lithium battery will passively stay in a fully charged state for a long time. The lithium battery itself is not suitable for being fully charged for a long time, otherwise it will affect the battery life. Disclaimer: Some pictures and content of the articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: Lead-acid battery life is so short?