When assembling lithium batteries, we must pay attention to these problems
1. Precautions for the use of cells, including cell selection, aluminum-plastic composite film, top edge sealing (pole edge edge sealing), side edge sealing, pole shank protection and measures to avoid mechanical impact and short circuit.
1. The problem of battery screening, how to distinguish between good and bad after the battery is in hand. Must use internal resistance tester, capacity tester. Test how much MH is nominal, and how much is actually MH. The larger the distance from the nominal parameter, the worse the quality. The lower the internal resistance of the battery, the better. The battery is a pit, check and test if there is equipment, buy lottery tickets if there is no equipment
2. Aluminum-plastic composite film outer packaging protection: mainly to avoid damage from being stabbed by sharp parts. To this end, the surrounding environment of the battery should be cleaned frequently, and sharp parts should not be touched or collided with the battery. Gloves can be worn when handling to avoid scratching the surface of the battery with fingernails.
3. Protection of top sealing edge and side sealing edge: In order to avoid damage to the top sealing edge and side sealing edge and destroy the sealing effect, it is forbidden to bend the top sealing edge and side sealing edge; at the same time, the design of the cell must adopt reliable insulation isolation Measures to avoid butt short circuit between the negative electrode and the aluminum-plastic composite film.
4. Pole handle protection: The positive terminal of the polymer lithium battery cell adopts an aluminum pole handle, and the negative terminal adopts a nickel pole handle. Because the pole handle is thin, bending should be prohibited; at the same time, the contact between the pole handle and the aluminum-plastic composite film should be avoided during the production process, and the ferrule film should be strictly isolated.
5. Insulation protection: In order to prevent short circuit of battery polarity when assembling multiple single cells in series, it is necessary to carry out insulation treatment, use PC film or silicone sheet at the position of the battery tabs
Spaced and then wrapped multiple layers of insulating tape to fix it, and then added a layer of insulating layer where the wires were soldered, and then added stripe tape to fix it.
6. Avoid mechanical impact, such as falling, hitting, bending the battery and accidentally trampling on the battery.
7. It is forbidden to use metal objects and wires to short-circuit the positive and negative electrodes.
8. Waterproof protection: After the lithium battery is assembled, the whole is poured with insulating glue and then packaged. Or choose a waterproof battery case.
9. The battery pack is required to be shockproof! Electric vehicles cannot be used as off-road vehicles! It is also not possible to use the outer skin of the battery pack to achieve buffer collision, and deformation will cause a short circuit! Try to use the method of grille bracket + buffer pad + outer box. Without the grille bracket, the battery pack will cause the nickel sheet to fall off under the pressure of the activities over the years!
10. Do a good job of heat dissipation, and use thermal grease pad as the medium to guide the heat to the stainless steel shell. Or the battery pack can provide a heat conduction channel conditionally. During the energy conversion, the heat conduction can be optimized in time to realize the optimization of the battery. Steel outer box + fan assist, both are conventional solutions.
11. The problem of anti-corrosion, the battery will rust after a long time, and try to take anti-corrosion measures as much as possible.
2. After a battery cell is completed, the next step is to correctly combine it with the shell and the battery cell protection circuit module to make it a polymer battery. The precautions in this process are as follows:
1. Shell design:
(1) Sufficient mechanical strength to avoid mechanical damage to the cell by external force,
(2) When the battery cell is installed in the casing, avoid the sharp corners of the casing from scratching the battery core;
(3) Prevent the short circuit caused by contact between the pure aluminum of the aluminum-plastic composite film interlayer and the outside.
2. The cell protection circuit must be designed: including the scientific setting of the highest/lowest voltage, overcurrent protection, and overcharge and overdischarge protection for the battery unit (single cell) when the cells are used in combination.
3. The transfer of the anode aluminum pole handle through the nickel strip, and the connection between the cell and the circuit board should be implemented by ultrasonic welding or spot welding technology.
4. Reliable positioning of the battery cell. After the battery cell is assembled, it should be fastened firmly in the casing, and will not loosen at will, so that the entire lithium battery structure is in a consolidated state.
