Lead acid and lithium battery which is better _ lithium battery and lead acid battery comparison analysis

Most people will be more concerned about the price and the most important parts of the electric vehicle before buying a car. There are two kinds of batteries in the market: lead-acid batteries and lithium batteries, which also largely determines the overall price. Lead-acid batteries are cheap, and lithium batteries are expensive. This makes many consumers discourage lithium batteries and choose lead-acid. battery.

At present, the place where electric vehicles are sold, whether it is battery brands, styles or brands, is diverse, and lead-acid batteries and lithium batteries occupy the dominant position. The following small series makes you more clear about the relationship and difference between the two.

Usually, the lead-acid battery pack weighs 16-30 kg and has a large volume. The lithium battery generally weighs 2.5-3.0 kg and has a relatively small volume, so it is easy to ride and easy to carry. From the quality point of view, the quality of the two is difficult to define, but consumers can buy a good quality battery produced by a regular manufacturer according to their actual needs.

The cost of the main material such as the positive electrode material, the negative electrode material, the current collector, the separator, and the electrolyte of the lithium battery is much higher than that of the lead-acid battery. The assembly materials and external circuitry of lead-acid batteries are extremely low cost.

Due to the manufacturing process, the labor cost of the lithium battery is relatively large. In the manufacturing cost, the labor cost of the lithium battery accounts for more than 40%, and the labor cost of the lead-acid battery is generally 10% to 20%.

The mechanical equipment used in the production of lithium batteries is expensive, the value is high, and the depreciation loss of mechanical equipment is large. Most processes in lithium batteries are irreversible, and lead-acid batteries are reversible repair and reuse. The recovery value of lead-acid batteries after use is above 40%, while the recovery value of lithium batteries is almost zero.

Lithium batteries are more than three times higher than lead-acid batteries, regardless of volumetric energy or weight-to-weight energy. Lithium batteries are smaller and lighter. Long cycle life. The cycle life of lithium batteries used in electric vehicles is generally more than 800 times. The lithium batteries using lithium iron phosphate cathode materials can reach 2000 times, which is 1.5 to 5 times higher than lead-acid batteries. This greatly reduces the cost of using the lithium battery, prolongs the service life and improves the ease of use. Has a wide range of charging power. This is a unique advantage of lithium batteries. When necessary, the charging time can be controlled from 20 min to 1 h, and the charging efficiency is over 84%. Based on further technological innovation, this feature will be better played.

We know that general comparison of energy storage products should be carried out from the perspectives of weight energy density, volumetric energy density, service life, price, applicability, national policy, etc.:

Weight energy density

The current lithium battery energy density is generally 200~260wh/g, lead acid is generally 50~70wh/g, then the weight energy density lithium battery is 3~5 times of lead acid, which means lead in the same capacity. The acid battery is 3 to 5 times that of the lithium battery, so the lithium battery has an absolute advantage in energy storage devices.

Volume energy density

The volume capacity density of a lithium battery is usually about 1.5 times that of a lead-acid battery, so in the case of the same capacity, the lithium battery is about 30% smaller than the lead-acid battery.

Use cycle

At present, the more popular material systems are ternary and iron-lithium. The number of cycles of ternary power lithium batteries is usually more than 1000 times, the number of cycles of lithium iron phosphate batteries is more than 2000 times, and the number of cycles of lead-acid batteries is usually only 300~350. The time is about three times, so the service life of the lithium battery is about 3-6 times that of the lead-acid battery.

price

At present, the price of lithium batteries is more expensive than lead acid, which is about 3 times. However, combined with the analysis of service life, the same cost is still used, and the life cycle of lithium batteries is still longer.

applicability

Lithium batteries are slightly worse than lead-acid batteries because of their safety. Therefore, various safety precautions must be taken during use, such as preventing external batteries or accidents from causing damage to lithium batteries, as this may cause fire or explosion; Temperature applicability is also very good, so in other aspects of compatibility, lithium batteries are no less inferior to lead-acid batteries.

National policy

Lead-acid batteries are very serious because of the environmental damage caused by production links or discarded batteries. Therefore, from the perspective of national policy, it has restricted the reinvestment of lead-acid batteries, or restricted the use of lead-acid batteries in some areas. In the future, the trend of replacing lead-acid batteries with lithium batteries will become more apparent, and the progress will gradually increase.