As for the reason for the temperature rise of copper foil soft connection, I think everyone knows that when the conductor has resistance, the current will heat up and make the product temperature rise. This is a physical property, which cannot be eliminated, but it needs to be controlled within an acceptable range. The heating of the copper soft connection will affect the safety of the battery. If the temperature rise is too high, it will produce a very dangerous situation, so this point is strictly controlled by the battery manufacturers. There are two reasons for the high temperature rise of copper foil soft connection, one is the purity of copper material, the other is the electroplating quality control. 

1. The main problem of the high heating of the copper flexible bar should be the choice of copper substrate, especially the purity of copper material. We think the reason why the temperature rise of that customer is too high may be that there is no qualified copper foil in the choice of copper material. There are too many impurities in the copper foil, and the resistance is large. The greater the resistance, the more heat will be generated, and the whole will exceed the standard. Our supplier's copper foil test report shows that the purity is 99.99%. 

2. The copper foil soft connection will be electroplated, and the conductivity of the electroplated layer will also affect the heating. For products with high temperature rise requirements, we recommend silver plating, but generally nickel plating. The thinner the electroplated layer is, the smaller the heating will be and the faster the heat dissipation will be.