Li-ion power lithium-ion battery planning

An example of lithium-ion power lithium-ion battery planning This method is based on the requirements of the company’s marketing department and combined with actual conditions. The customer's specific requirements are as follows: 8Ah25V lithium-ion power lithium-ion battery should be supplied with two housings of the same volume. The internal standard of the shell is 133mmX95mmX65mm, the pole of the battery is connected, and the normal working current is 3A. The specific planning process is as follows: 3.1 Number of single cells The operating voltage of the lithium manganese oxide battery is 3.7v, and the assembly of a 25V battery pack requires 7 single cells. 3.2 Battery capacity planning Assume that C is equal to C multiplied by k1, where C is the planned capacity of the battery; C/rated capacity of the battery, 8.0Ah; the safety factor of K1 battery according to the battery planning, generally 1.1~1.2. Here we take min as 1.1, and then set C to 8.0X1.1u003d8.8Ah. 3.3 Battery standard planning According to the standard of the battery pack shell, combined with the number of batteries required, one shell puts 4 batteries, and the other shell puts 3 battery. The external standard of the single battery is: 130mmX60mmX22.5mm (including the pole), and the external standard of the battery shell is: 120mmX60mmX22.5mm. Taking into account the high requirements for safety performance of the power battery, an explosion-proof hole is reserved on the shell as a device to prevent the battery from exploding under abnormal conditions. 3.4 The density planning is extremely one-sided. Under normal circumstances, the specific capacity of the positive active material of lithium manganate is 90mAh/g, and the specific capacity of the negative active material of carbon is 330mAh/g. This method is calculated based on the remaining 10% of the negative active material, so the dosage of the positive active material and the negative active material is as follows: W+u003d8800/90u003d97.8W-u003d8800*(1+10%)u003d29.3g/330 According to test data and practical experience, in lithium manganese oxide power lithium-ion batteries, the density of the positive electrode is generally 440g/m2, and the corresponding density of the negative electrode is 145g/m2. When considering the height of the 3.5 pole height plan, the following aspects should be paid attention to: There should be a certain space at the top of the battery. In order to prevent the increase in the internal pressure of the battery during charging, plus enough space, the height of the negative electrode is generally 2 to 4 mm higher than the anode, and the height of the gap is 2 to 4 mm higher than the cathode. . Summarizing the above elements, combined with the battery casing standard, it is recognized that the battery positive plate height is 102mm, the negative plate height is 106mm, and the gap height is 110mm. 3.6 Calculate the length of the pole piece The positive active material content is 92%, and the pole piece length is: Lu003d27.8/0.92/442/0.102u003d2.369m According to actual operation requirements, the positive electrode is divided into four sections. The length of each section is 600mm. A certain blank area should be left for the electrode ears. Considering that the negative electrode should be completely covered by the positive electrode, the length of the negative short film material is 610mm, and the length of the blank copper filling should be reported according to actual requirements. Combining the test data and actual operation related experience with 3.7 sheet thickness admission, the compaction density of lithium manganese oxide positive electrode data is about 2.6, and the compaction density of graphite carbon powder is about 1.5, so the thickness of the positive electrode sheet is about 185 meters in this plan, and The thickness of the negative electrode sheet is about 110 meters. 3.8 Winding needle planning Power lithium-ion battery winding needles can be divided into round winding needles, square winding needles and oval winding needles according to the shape of the battery. Because the planned battery is a square battery, a square coil needle is selected. According to the detailed ruler of the battery, combined with relevant practical experience, the width of the stitch is 40mm and the thickness is 1mm. 3.9 The standard recognizes that the length of the gap with a barrier is generally twice that of the negative electrode, and the width is 2~4mm longer than the height of the electrode plate. In combination with the safety function requirements of power lithium-ion batteries, this method uses a three-layer PP/PE/PP gap with a thickness of 35 meters. 3.10 Electrolyte confession Currently, 1mol/L LiPF3/ec-dmc-emc (1:1:1) is commonly used in lithium-ion power lithium-ion batteries. The power consumption of lithium cobalt acid battery is 3.5~4g/Ah, while the power consumption of yolk carp battery is 5.5~6g/Ah. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: Instructions for disassembly of lithium battery