18650 lithium cells pack assembly method

Few characteristics of 18650 lithium battery pack assembly need to understand:

1. The 18650 lithium battery pack is assembled by welding multiple 18650 cells in series and in parallel;

2. The 18650 lithium battery pack needs a battery protection board to balance and protect each 18650 battery cell;

3. The voltage error between each cell of the 18650 lithium battery pack should be within 10 millivolts, and the difference in capacity and internal resistance should be as small as possible;

4. The voltage of each cell of the 18650 lithium battery pack has two conventional voltages, one is the voltage of a conventional lithium-ion battery, and the other is a lithium iron phosphate battery of 3.2V;

5. The batteries used in the assembly of the 18650 lithium battery pack must be of the same type, and the old and new batteries cannot be mixed together, preferably batteries produced in the same batch;

So 18650 lithium battery pack assembly needs to prepare the following main things:

1. Determine the voltage and capacity of the 18650 lithium battery pack that need to be paid attention to;

2. Prepare the corresponding number of 18650 lithium battery cells;

3. Choose a suitable lithium battery protection board;

4. Welding equipment, battery cell holders, wires, battery casings, etc. and other auxiliary materials;

Let's take a look at the analytical diagram of the assembly structure of the 18650 lithium battery pack:

From the picture, we can see that the 18650 lithium battery pack is assembled by connecting cylindrical 18650 lithium battery cells in series and parallel. After welding and fixing, after connecting the lithium battery protection board and installing the battery casing, An 18650 lithium battery pack is simply completed in this way.

Let's talk about the reasons for several problems to be understood in the assembly of 18650 lithium battery packs:

1. I believe many friends should know the reasons for using battery protection boards, so I won’t say more here;

2. The smaller the cell voltage, capacity, and internal resistance error, the better. If the voltage error is large, the high-voltage cell will automatically charge the low-voltage cell, so that some cells in the battery pack will be overcharged. The battery cells are "starved"; the internal resistance error is too large, resulting in unbalanced heating of the battery cells, unbalanced energization rate, etc.; the capacity error is too large, some of the cells are used up, and the other part is not, which will cause part of the battery. The core is over-discharged and damaged; these factors will damage the efficiency of the 18650 lithium battery pack, and the service life will be reduced, otherwise it can improve the efficiency and life;

3. The 18650 lithium battery pack requires the use of the same type of attributes, and the old and new batteries cannot be mixed together. It is best to use the batteries produced in the same batch, mainly because of the reasons mentioned in the above 2 points.

After passing the above knowledge points about the 18650 lithium battery pack assembly method, I believe that everyone should have a better guidance on how to DIY 18650 lithium battery pack assembly. As for other electronic components such as battery protection boards, you need to know more about it, and believe that you can assemble 18650 lithium battery packs with a certain voltage and capacity by yourself.