There are many reasons, and they vary. The following factors may exist:
1. The electrode paste surface is too high.
2. The melting point of the electrode paste is too low and melts too fast.
3. The volatile matter is too high and the sintering is too slow.
4. Too much pressure.
5. Poor contact of the conductive plate stabbed and burned.
6. The welding quality of the electrode shell is not good.
7. Insufficient current and insufficient roasting.
8. Defects in pressure ring (or contact element) and other equipment.
In production practice, depending on the specific circumstances, there may be many factors. Everyone is welcome to communicate.