How to define the Grade A cells?
1. Consistency of LiFePO4 Battery
Consistency is a topic that every battery can’t get around. Because most batteries exist in the form of battery packs, few people use a battery (or cell) alone, so the consistency determines the performance of the entire battery pack.
According to the Cannikin Law (The theory is controversial, but it’s a good explanation for batteries), the overall performance of the battery pack will depend on the cell with the weakest performance, and the entire battery pack will not be able to fully release electricity or absorb electricity due to the weakest cell. lifespan is getting shorter. And good quality LiFePO4 battery should have excellent consistency.
It is not difficult to test the consistency of LiFePO4 batteries by yourself. You only need to connect the cells in series, and then perform 1C charging and 3C discharging. During the charging and discharging process, you can observe the difference between the rise and fall of the cell voltage. A small range of differences proves that the consistency is better.
2. Self-discharge Rate of LiFePO4 Battery
At present, LiFePO4 batteries have a wide range of capacity specifications, and the more common ones can be purchased from 20Ah to 302Ah. Of course, there will also be batteries smaller than 20Ah or larger than 302Ah. The self-discharge rate of a good quality LiFePO4 battery is generally about 3% by default and about 2% in winter. It is generally believed that the smaller the self-discharge rate, the better, and the excessively large self-discharge rate is a problem with the quality of the LiFePO4 battery.
The self-discharge rate detection method is very simple, as long as the battery is fully charged, record the data, and then let it stand for a month, then measure the power, and finally calculate the gap with the fully charged state.
3. Charge and Discharge Rate of LiFePO4 Battery
One of the advantages of LiFePO4 batteries is that they can withstand high rates of charge and discharge. Generally speaking, the charge-discharge rate of a good-quality LiFePO4 battery is relatively high and the higher the better.
The test method is still not difficult. At present, most LiFePO4 battery manufacturers will indicate that they support charging at a rate of 3C. As long as the relevant charger is used for charging, it can be judged by observing whether the LiFePO4 battery is abnormally hot.
4. Internal Resistance of LiFePO4 Battery
At present, the internal resistance of LiFePO4 batteries will float around 0.2Ω. Of course, the smaller the internal resistance, the better. The smaller the resistance, the larger the current can pass through, and the loss can be effectively reduced.
The method of measuring internal resistance is even simpler, using a multimeter will do the job perfectly.
5. Overall Quality Control of LiFePO4 Battery
In fact, to put it another way, it is to choose a big brand battery with a better reputation. Brands with a good reputation generally do not allow too many errors and defects in their products. This is why the factories of these battery brands spend a lot of money on quality control every year. Of course, as long as the quality control of the brand is in place, you can The greater the probability of buying a good quality LiFePO4 battery.
The problem can be solved by choosing an impressive brand, such as CATL, EVE, whose overall LiFePO4 cell level is better.
Summary
The high quality of LiFePO4 battery is not only for battery manufacturers but also for battery suppliers. Under the condition that either party does the best, as a customer, you can get the best quality LiFePO4 batteries. Of course, the follow-up of LiFePO4 battery normal use is also a good habit to keep. In this way, you can enjoy the pleasure brought by the LiFePO4 battery for a long time.
