How to activate the protection board of a lithium-ion battery pack?
Currently, not all lithium-ion battery pack protection boards need to be activated; only some protection ICs do. This is an older IC method, and the reason for this is to prevent the protection board from operating, thereby reducing electrostatic discharge energy and allowing the lithium-ion battery to be stored for a longer period. This is why the design requires charge activation.
If the protection board needs to be activated by charging or completely disconnecting the load after current limiting protection, it will be more troublesome. However, you can short-circuit B- (battery negative) and P- (discharge negative) to release the protection. Remember not to bring a large load when short-circuiting, otherwise it may produce a lot of sparks. The reason is that a large voltage difference is formed across the discharge MOS after protection. Short-circuiting directly resets the DS level of the discharge MOS to 0V, and the protection is released at this time.
Lithium-ion battery protection board principle analysis:
The need for protection in lithium-ion battery packs stems from their inherent characteristics. Because the materials used in lithium-ion battery packs dictate that they cannot be overcharged, over-discharged, over-currented, short-circuited, or subjected to excessively high temperatures during charging and discharging, lithium-ion battery modules are always accompanied by a sophisticated protection board and a current fuse.
The protection function of lithium-ion battery packs is usually accomplished by the cooperation of protection circuit boards and current devices such as PTC. The protection circuit board is composed of electronic circuits that accurately monitors the voltage of the cells and the current of the charging and discharging circuit at all times in an environment ranging from -40℃ to +85℃, and controls the opening and closing of the current circuit in a timely manner. The PTC prevents the battery from being severely damaged in high-temperature environments.
A typical lithium-ion battery pack protection board usually includes a control IC, MOS switches, resistors, capacitors, and auxiliary components such as FUSE, PTC, NTC, ID, and memory. The control IC, under normal conditions, controls the MOS switches to conduct, connecting the battery cell to the external circuit. When the cell voltage or circuit current exceeds a specified value, it immediately controls the MOS switches to turn off, protecting the battery cell.
When the protection board is functioning normally, Vdd is high, Vss and VM are low, and DO and CO are high. When any of the parameters Vdd, Vss, or VM changes, the level of the DO or CO terminal will change.
