Comparison between lead-acid batteries and lithium batteries

Speaking of lead-acid batteries, the first application we can think of is electric bicycles. In fact, according to its structure and use, the industry's lead-acid batteries are divided into four categories: 1, start-up 2, power use 3, fixed valve-controlled seal type 4, small valve-controlled seal type. This method is mainly classified from the structural aspect, but also wants to take into account the use. It is difficult for non-battery practitioners to understand. If it is classified from the perspective of pure market application, it is better to understand. According to this standard, lead-acid batteries are used. Divided into two categories:

1, the main power supply, including: communications equipment, industrial equipment, power control machine tools, portable equipment;

2, backup power, including: emergency equipment, communication base stations, electronic switch systems, solar systems. This type of application has many intersections with the application of lithium-ion batteries . In terms of market capacity, this intersection is mainly concentrated on power batteries , such as electric bicycles and small passenger cars. In the field of power batteries, the main reason is the dispute between these two technologies. Therefore, we compare the difference between lead-acid batteries and lithium batteries in this field . Otherwise, the reference materials are uncertain, and the comparison is boundless.

The difference between the two is based on the performance of the material. The positive and negative materials of lead-acid batteries are lead oxide, metal lead and concentrated sulfuric acid. The lithium-ion battery has four components: positive electrode (lithium cobalt oxide/manganese) lithium / lithium iron phosphate / three yuan), graphite negative electrode, a separator and an electrolyte, thereby resulting in a different are:

1, different from the nominal voltage: 2.0V single lead-acid batteries, lithium batteries single 3.6V;

2, Different energy density: lead-acid battery 30WH/KG, lithium battery 110WH/KG;

3, cycle life is different, lead-acid battery average 300-500 times, lithium battery up to thousand times, two mainstream technical routes from lithium battery In view, the difference between the ternary lithium battery and the lithium iron phosphate battery is relatively large, the discharge life of the ternary lithium battery is 1000 times, and the life of the lithium iron phosphate battery can reach 2000 times;

4. Charging mode: The lithium battery adopts the voltage limiting current limiting method, that is, the threshold value is given for both current and voltage, and the charging method of the lead acid battery is more. The main ones are: constant current charging method, constant The charge charging method, the stage equal-current charging method, and the floating charge cannot be described one by one.

The above are the differences in the electrical performance characteristics of the two based on the different working principles. In addition, there are two other factors that affect the promotion of the two: safety and cost, which can be called market factors. Lithium batteries are dominant in terms of electrical performance characteristics, and lead acid batteries are dominant in market factors.

1. Safety: The high-current discharge of lead-acid batteries is not prone to accidents because it has a high sealing property. Even if there is an accident (such as leakage), the positive and negative electrodes and the lead-acid electrolyte are not flammable. The electrolyte of a lithium ion battery is an ester solution, which is flammable and volatile. The working principle of lithium battery is that lithium ion is embedded through the diaphragm between the positive electrode and the negative electrode, and a large current passes through to form lithium dendrite. These two factors are the root cause of the burning and explosion of the lithium battery.

2. Cost: The materials and work requirements for lead-acid batteries are much lower. As far as electric bicycles are concerned, lithium batteries are the value of the entire electric vehicle assembled with lead-acid batteries.

In the electric bicycle and small family car market, lead-acid batteries and lithium batteries are in use. Because of their comparative advantages, lithium batteries have electrical and convenience advantages, while lead-acid batteries have safety and cost advantages. These two types of batteries perform equally well in other applications.