The problem of large internal resistance of battery protection board
Lithium battery protection board is a circuit board composed of electronic components and PCB. It is always ready to monitor the voltage of the cell and the current of the charging and discharging circuit under a certain temperature and humidity environment, and timely control the on-off of the current circuit. Since the lithium battery protection board is so important, we should understand some common problems of the protection board. Next, Hercules protection board will explain the problem of large internal resistance of the protection board
The internal resistance of MOS is relatively stable. In case of large internal resistance, first consider whether the internal resistance of component fuse or PTC is too large. If the resistance value of component fuse or PTC does not change, check the protective plate structure to detect the through-hole resistance value between P +, p-pad and component surface. The through-hole may be slightly broken and the resistance value is large.
If there is no problem with fuse or PTC, check whether MOS is abnormal: first, determine whether there is a problem with welding; Secondly, the thickness of the Kanban (whether it is easy to bend), because the bending may lead to abnormal welding of the pin; Then put the MOS tube under the microscope to observe whether it is broken; Finally, test the MOS pin resistance with a multimeter to see if it is broken down.
If the internal resistance is still large, we need to use the probe to contact the protective plate to see whether it has poor contact or excessive oxidation. Secondly, we should also pay attention to whether there are more nickel sheets on the cell. If the number of nickel sheets on the cell is too large, it will also cause excessive internal resistance.
Many similar problems can be avoided by selecting a well-known and dedicated manufacturer of lithium battery protection board. After years of development, Hercules protection board has a high popularity and strength in the field of lithium battery protection board.