After receiving 200 18650 batteries from 11 a.m., we started to make 8 and 21 strings of ternary lithium battery packs. 2 per battery5 Ah and then 8 Ah should be 20 Ah instead. After the ternary lithium battery is fully charged, 21 strings can reach 882v。My original 72V lithium battery charger is suitable for charging 20 strings of lithium battery packs, not for the lithium battery packs I want to make now.
Assembling lithium batteries is mainly two major steps, which should be completed quickly.
The first step is to correctly arrange and combine the lithium batteries, and the second step is to properly weld the protection plate.
However, by 7 p.m., I couldn't assemble it properly, so I had to stop work, and I had to buy a new 210 155 290 case to put the battery pack in.
Causing me to install so long, what's the problem?
1. Arrange and combine into 22 strings, which is contradictory to the protective board that is only suitable for 21 strings. Because it has already been welded, it is more difficult to remove the excess string.
2. Because it is installed in two layers, there is an error when welding 11 strings and 10 strings, and the welding error is found when measuring the voltage difference of the row line with a multimeter.
The rule of thumb should be to watch the correct sequencing on the table before welding, rather than just because it is a pole to connect two rows together.
3. The welding of the protection plate should be from the total positive electrode, and I started the electric welding from the total negative electrode, theoretically speaking, it should be no problem, and the last wire should be connected to the total positive electrode. Since I initially arranged and combined into 22 strings, the last wire could not be connected to the total positive. Had to re-weld.
4. It also took a lot of time to cut the insulating plastic board.
5. After the packaging was almost finished, I found that a thick wire had to be welded on the total positive electrode to connect with the charging cable of the shell product, and I actually forgot about it. I had to stop work.
6. Emotion: I have to admire Tesla, he said that all his inventions and creations have formed a very clear structure in the brain, and the details are very clear, to the point that there is no need to draw the design drawings and then create. However, I couldn't form a correct and clear spatial sorting diagram in my brain with 21 strings of lines, so I could only do it step by step, correct the mistake after finding the problem, and then find the problem and then correct the error.
Alas, with a sigh, ordinary people are ordinary people!