Basic Knowledge of Lithium Batteries

1. What is the difference between primary batteries and rechargeable batteries?

Based on the electrochemical composition and the structure of the battery electrodes, it can be seen that the internal structures of rechargeable batteries are reversible. Theoretically, this reversibility will not be affected by the number of cycles. Since charging and discharging will cause reversible changes in the volume and structure of the electrode, the internal design of the rechargeable battery must support this change. Primary batteries’ internal structure is much simpler and irreversible, so they cannot be charged. If it needs to be used repeatedly, you should choose a rechargeable battery.

2. Are there any other differences between primary and secondary batteries?

Another obvious difference is their energy and load capacity, as well as their self-discharge rate. Secondary batteries have much higher energy than primary batteries, but their load capacity is relatively small.

3. What are the pros and cons of rechargeable portable batteries?

Rechargeable batteries have a long lifespan and can be cycled more than 1,000 times. Although they are more expensive than dry batteries, they are more cost-effective if used frequently. The capacity of rechargeable batteries is lower than that of alkaline manganese batteries or zinc-carbon batteries of the same specification, so they discharge faster. Another disadvantage is that due to their nearly constant discharge voltage, it is difficult to predict when the discharge will end. When the discharge is completed, the battery voltage drops suddenly. If you use it on a camera and the battery suddenly runs out of power, you will have to stop using it. On the other hand, rechargeable batteries can provide higher capacity than most primary batteries. For example, Li-ion batteries are widely used in photographic equipment because of their high capacity, high energy density, and discharge voltage that gradually decreases with increasing depth of discharge.

4. How do rechargeable batteries achieve their energy conversion?

Every battery can perform electrochemical conversion, which is to convert stored chemical energy directly into electrical energy. In the case of secondary cells (also called storage batteries or rechargeable portable batteries), chemical energy is converted into electrical energy during discharge, and electrical energy is converted back into chemical energy during charging. This process can generally be charged and discharged more than 500 times. Depending on electrochemical systems, our company's Li-ion products can be repeatedly charged and discharged more than 1,000 times. Li-ion is a new type of rechargeable portable battery. Its rated voltage is 3.6V, and its discharge voltage gradually decays with the depth of discharge, unlike other rechargeable batteries, where the voltage suddenly drops at the end of discharge.

5. What are the “green batteries” currently in use and research?

New green and environmentally friendly batteries refer to a type of high-performance, pollution-free batteries that have been put into use or are being developed in recent years. For example, lithium-ion batteries, nickel metal hydride batteries, mercury-free alkaline zinc-manganese batteries, lithium or lithium-ion plastic batteries, combustion batteries, and electrochemical energy storage supercapacitors are all new green, and environmentally friendly batteries. In addition, it also includes solar cells that use solar energy for photoelectric conversion, which are currently widely used.

6. Which batteries will dominate the battery market?

With cameras, mobile and cordless phones, laptops, and multimedia devices occupying an increasingly important position in household appliances, secondary batteries, i.e. rechargeable batteries, are widely used in these fields compared with primary batteries. Secondary rechargeable batteries will develop in the direction of small size, light weight, large capacity, and intelligence.

7. What is a lithium-ion battery?

It refers to a rechargeable battery with lithium ions as the active substance. When the battery is discharged to the termination voltage, it can be recharged to restore to the state before discharge.

8. What characteristics of lithium-ion batteries are related to the model?

The length, width, height, and capacity of the battery.

9. What are the two most important factors affecting the cycling performance of lithium-ion batteries?

The properties of active substances and the types and contents of impurities.

10. What is the active positive electrode material of an ion battery?

Lithium salts, such as lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, etc.

11. What is the active negative electrode material of an ion battery?

Graphite powder

12. What is the composition of the electrolyte in an ion battery?

Commonly used ones are lithium hexafluorophosphate, lithium tetrafluorophosphate (LiPF6, LiClO4), etc.