Any battery is an electrochemical process that produces electrons to gather at the negative electrode. Once the battery is turned on, electrons flow from the negative electrode to the positive electrode to generate current. Since it is a chemical reaction process, gas will be produced. The more impurities in the gas or gas, the easier it is for the button cell to expand. A good button cell will not bulge;

1, high shell hardness and good sealing performance,

2, there is a proper amount of exhaust,

3. The purity of battery raw materials is high, and there are few impurities in the gas.