How to test the capacity of lithium batteries? I believe many friends have many methods. One of the main reasons for testing the capacity of lithium batteries is to see if the manufacturer has virtual capacity, to see if the battery products of the battery manufacturer are reliable, and to see if the actual capacity of lithium batteries can meet the electrical parameters requirements of the designed products. Here are a few simple methods for testing the capacity of lithium batteries.

1. Method for testing the capacity of lithium batteries in practical use

Although this method is relatively simple, it requires high operational requirements. The specific operation is as follows:

(1) Prepare a current flow meter and an electrical appliance with rated working current and voltage requirements, such as a product with a rated working current of 2A, symbol I, voltage of 12V, symbol V;

(2) Purchase one or several different brands of 12V lithium batteries with an allowable discharge current of 2A or more, preferably with the same battery capacity. If all batteries are 6000mAh, the symbol is C;

(3) Connect the battery to the electrical appliance and install a current flow meter, allowing the appliance to operate at the rated current and voltage until the appliance becomes weak or abnormal. If the working time is T (this difficulty lies in the difficulty of controlling the rated working efficiency of the appliance), it is considered to have stopped;

So it can be tested that the capacity of the lithium battery is: C=IT

2. Method for calculating and estimating the capacity of lithium batteries using formulas

The capacity of a lithium battery is related to its model size and depends on its thickness, width, and length. It is also related to the material and size of the battery. The actual calculation formula for the capacity of polymer lithium batteries is complex and does not have a linear relationship with volume. It is necessary to consider many factors, such as different materials, which have a significant impact on the actual capacity. The larger the size, the larger the capacity/volume ratio.

The commonly used estimation formula for quickly estimating the capacity of polymer batteries (estimation only) is:

Capacity=thickness * width * length * K (K in mah/mm3)

The range of K value is (0.07~0.11), which depends on the material industry and the size of the capacity. The larger the capacity, the larger the K value, the smaller the capacity, and the smaller the K value (which can be understood as the larger the size, the larger the K value). In actual calculations, the K value can be defaulted to 0.1. For example, 103450LP (10mm thick, 34mm wide, 50mm long) has a calculated capacity of 10 * 34 * 50 * 0.1=1700, and the actual capacity is above 1800mah; For example, 603048LP (6mm thick, 30mm wide, 48mm long) has a calculated capacity of 6 * 30 * 48 * 0.1=864, and the actual capacity can reach 900mah.

The above are two simple and commonly used methods for testing the capacity of lithium batteries. From an accuracy perspective, it is obvious that the first method tests the capacity of lithium batteries more accurately, while the second method is less accurate. After all, it is a theoretical estimation and is affected by many factors. From a convenience perspective, the second method is obviously more convenient because it basically does not require any tools, As long as you know the volume and K value of lithium batteries (usually different manufacturers have different k values, mainly due to differences in the production process and material formula of battery manufacturers), you can quickly estimate the approximate capacity of lithium batteries.

Shenzhen Topband Battery Co., Ltd.，established in 2006, is a wholly-owned subsidiary of Shenzhen Topband Co., Ltd. (002139.SZ). We focus on lithium iron phosphate batteries,with independent research and development in cells and BMS. With the ability to integrate the entire industry chain, we are committed to providing customers with one-stop lithium battery solutions and services. Our quality products are widely used in energy storage and light power.