What are the advantages, disadvantages and differences between lead-acid batteries and lithium batteries?
Is it better to choose lead-acid batteries or lithium batteries for electric vehicle batteries? In fact, there is no absolute certainty for this question. Let's first look at the advantages and disadvantages of lead-acid batteries and lithium batteries.
First of all, we need to understand what lead-acid batteries are and what lithium batteries are.
●What is a lead-acid battery
Lead-acid battery (VRLA) is a battery whose electrodes are mainly composed of lead and its oxides and whose electrolyte is sulfuric acid solution. In the discharge state, the main component of the positive electrode of the lead-acid battery is lead dioxide, and the main component of the negative electrode is lead; in the charging state, the main components of the positive and negative electrodes are lead sulfate.
Advantages and disadvantages of lead-acid batteries
1. Good safety performance. Lead-acid batteries are easy to maintain and can continue to be used after being damaged, with a little repair.
2. Cheap price. The price of lead-acid batteries is about 1/3 of that of lithium batteries, which shows that they are cheap.
3. Recyclable and reversible. Lead-acid batteries are highly recyclable. After the lead-acid batteries are worn out, they can go to the electric vehicle store to replace the old batteries with new ones. After making up the difference, they can replace a new set of batteries, which can minimize the loss, which is a great benefit for users. The lead in the battery can also be recycled to reduce environmental pollution.
4. Good temperature performance, can work in an environment of -40 ~ + 60 ℃;
Disadvantages of lead-acid batteries
1. Low energy density
The traditional lead-acid battery has a low mass and volume energy density, which is only about 1/3 of lithium-ion batteries and about 1/2 of hydrogen-nickel batteries, and is large in size, which is not suitable for light weight and small size occasions. In the future, there is still a lot of room to improve the energy density of lead-acid batteries
2. Short cycle life
The traditional lead-acid battery has a short cycle life, and the theoretical number of cycles is about 1/3 of that of lithium-ion batteries.
There is still a lot of room to improve the cycle life of lead-acid batteries, especially those lead-acid batteries that use new materials, new structures and new technologies, such as bipolar lead-acid batteries and lead-carbon batteries.
3. There is a risk of lead pollution in the industrial chain
Lead is the main raw material of lead-acid batteries, accounting for more than 60% of the battery mass. The global lead consumption of lead-acid batteries accounts for more than 80% of the total lead consumption. Lead is a heavy metal, and the lead-acid battery manufacturing industry chain (including primary lead smelting, battery manufacturing, battery recycling, and secondary lead smelting) has a high risk of lead pollution. Poor management will cause environmental pollution and endanger human health.
●What is a lithium battery
A lithium battery is a battery that uses metallic lithium or lithium alloy as the positive electrode material and a non-aqueous electrolyte solution. Because the chemical properties of metallic lithium are very active, the processing, storage and use of metallic lithium have very high environmental requirements. Lithium batteries can be roughly divided into two categories: lithium metal batteries and lithium-ion batteries.
Advantages and disadvantages of lithium batteries
1. Light weight and small size. The volume of a lithium battery is 2/3 of that of a lead-acid battery, and its weight is about 1/3 of that of a lead-acid battery. The capacity of a lithium battery of the same volume is higher than that of a lead-acid battery. The reduction in weight makes electric vehicles lighter, while the endurance increases by about 10%.
2. Long life. The average life of a lithium battery is about 4 years, which is about 1.5 times that of a lead-acid battery. It can be charged and discharged more than 500 times. The battery has no memory and is highly shock-resistant.
3. Good overcharge resistance and charge and discharge resistance. At room temperature, lithium batteries can be charged continuously for 48 hours without battery expansion, leakage, rupture and other accidents, and the capacity remains above 95%. Moreover, it can be charged and discharged quickly under a dedicated charger.
Disadvantages of lithium batteries
1. Expensive
The production cost of lithium-ion batteries is high, the production equipment is expensive, and the labor cost accounts for about 40% of the production cost. The price is about three times that of lead-acid batteries.
2. Low safety performance
At present, electric bicycles with lithium batteries basically use ternary lithium batteries. Although this type of lithium battery has a high capacity density, its electrolyte is flammable. In the event of a major abnormality, a violent explosion and fire accident may occur.