Advantages of lithium-ion batteries
1. Long cycle life: Lithium-ion batteries, when charged and discharged at a 1C rate, have a cycle life of ≥500 cycles, and their capacity at the 500th cycle is greater than 70% of the nominal capacity. In contrast, lead-acid batteries, even when discharged at 0.5C and charged at 0.15C, have a cycle life of ≤350 cycles and a capacity of ≤60%.
2. Good low-temperature discharge performance: Lithium-ion batteries can work normally at -25 degrees Celsius, and their capacity can reach 70% of the nominal capacity, while lead-acid batteries have only 50% of their capacity at -10 degrees Celsius and cannot work normally at -25 degrees Celsius.
3. Strong charge retention: A fully charged lithium-ion battery pack retains more than 80% of its capacity after being stored for two months, while a lead-acid battery retains only 40%-50% of its nominal capacity after two months.
4. Strong range: Since the weight of lithium-ion battery packs is only 30% of that of lead-acid batteries, lithium-ion batteries have a strong range under the same voltage and capacity.
5. High specific energy: Since the volume of lithium-ion batteries is only 30% of that of lead-acid batteries, lithium-ion batteries have a larger energy storage capacity than lead-acid batteries when using the same space.
6. Wide operating temperature range: Lithium-ion batteries can operate in the range of -25 degrees to 55 degrees, while lead-acid batteries can only operate in the range of 10 degrees to 40 degrees.
7. Short charging time: Because lithium-ion batteries can be charged with high current, the charging time is only 4-5 hours, while lead-acid batteries take 8 to 10 hours.
8. High green and environmentally friendly performance: Compared with lead-acid batteries, which contain a large amount of lead, a heavy metal that is harmful to the human body and the environment, lithium-ion batteries are highly environmentally friendly products.
9. Capable of high-current discharge: When lithium-ion batteries are discharged at a high current rate of 1C, their capacity is only 60% of the rated capacity.
10. High-current discharge does not affect cycle life: High-current discharge at a 1.5C rate has no impact on the cycle life of lithium-ion batteries. However, high-current discharge at a 1.5C rate for lead-acid batteries results in a cycle life of only 30%-40% of the nominal cycle life.
Working principle of lithium-ion batteries
A lithium-ion battery is a rechargeable battery that relies heavily on the movement of lithium ions between the positive and negative electrodes to function. During charging and discharging, Li+ ions repeatedly insert and extract between the two electrodes: during charging, Li+ ions extract from the positive electrode, pass through the electrolyte, and insert into the negative electrode, leaving the negative electrode in a lithium-rich state; the reverse occurs during discharging.
Lithium-ion batteries discharge through a chemical oxidation-reduction reaction. During discharge, which is when we use the battery and consume its power, lithium ions are inserted into the positive electrode and deposited into the negative electrode. Charging is the reverse process. This gain and loss of ions creates a voltage, resulting in a charge on the battery.
During each charge-discharge cycle, lithium ions (Li) act as carriers of electrical energy, repeatedly moving back and forth between the positive and negative electrodes. They react chemically with the positive and negative electrode materials, converting chemical energy into electrical energy and achieving charge transfer. This is the basic principle of a lithium-ion battery. Since the electrolyte and separator are electron insulators, there is no movement of electrons between the positive and negative electrodes during this cycle; they only participate in the chemical reactions at the electrodes.
