Battery ratio refers to the current value required when the battery releases its rated capacity within a specified period of time, which is an important indicator to measure the charge and discharge capacity of the battery.
1. Representation of magnification
It is usually denoted by the letter "C". For example, 1C means that the battery is charged and discharged with a current of the numerical size of its rated capacity. For example, a battery with a capacity of 2Ah is discharged at a current of 2A, which is 1C discharge; If it is discharged with a current of 4A, it is a 2C discharge. The same is true for charging.
2, the impact on battery performance
(1) Charge and discharge speed
High rate batteries can complete the charge and discharge process in a short time. For example, in some application scenarios that require fast charging, such as the fast charging mode of electric vehicles, high-rate batteries can greatly shorten the charging time and improve the efficiency of use.
However, high rate charging and discharging may also bring some problems, such as serious battery heating. Because in the process of high current charging and discharging, the chemical reaction speed inside the battery is accelerated, and more heat is generated. If the heat cannot be dissipated in time, it may affect the performance and life of the battery, and even cause safety problems.
(2) Capacity and cycle life
In general, when the battery is discharged at a high rate, the actual capacity released will be lower than the rated capacity. This is because at a high rate, the polarization phenomenon inside the battery is intensified, the internal resistance is increased, resulting in a faster voltage drop, and the discharge cutoff voltage is reached in advance, thus reducing the actual released capacity. Frequent charging and discharging at high rates will also adversely affect the cycle life of the battery. High rate charge and discharge will cause changes in the internal structure of the battery, such as pulverization of electrode materials, falling off, etc., thereby reducing the performance and life of the battery.
3, different types of battery rate characteristics
(1) Lithium-ion batteries
Lithium-ion batteries have high energy density and better magnification performance, and are widely used in consumer electronics, electric vehicles and other fields. Different types of lithium-ion battery rate performance is also different, such as lithium iron phosphate battery rate performance is relatively good, suitable for some charging and discharging speed requirements of the occasion; The ternary lithium battery has a high energy density, but the magnification performance is relatively weak.
(2) Lead-acid battery
The rate performance of lead-acid batteries is relatively poor, and can only be charged and discharged at a lower rate. However, the lead-acid battery has low cost and mature technology, and it still has a wide range of applications in some occasions where the charge and discharge speed is not high, such as startup batteries and energy storage batteries.
(3) nickel metal hydride battery
The rate performance of nickel-metal hydride battery is between lithium-ion battery and lead-acid battery, and has better charge-discharge performance and cycle life. However, nickel-metal hydride batteries have memory effects and need to be fully discharged regularly to maintain battery performance.
