The function of the protection board is mainly to protect the cell of the rechargeable battery, maintain the safety and stability of the battery during charging and discharging, and play an important role in the performance of the whole power battery circuit system. (for example, lithium battery is generally composed of cell, protective plate and shell, such as mobile phone battery)
Main functions of protection board
1) Overcharge protection function:
Overcharge protection function means that when a certain voltage (hereinafter referred to as overcharge detection voltage) is reached, it is prohibited to continue charging by the charger. That is, put the MOS tube controlling overcharge into the off state and stop charging.
2) Over discharge protection function:
The function of over discharge protection is to stop discharging the load when the voltage of the battery becomes low. Turn off the MOS tube that controls the over discharge and prohibit its discharge. This process is just the opposite of the action during overcharge detection.
3) Overcurrent protection function:
The over-current protection function is to stop the discharge of the load when large current is consumed. The purpose of this function is to protect the battery and MOS tube and ensure the safety of the battery in the working state. After overcurrent detection, the battery will return to normal after being separated from the load and can be recharged or discharged.
4) Short circuit protection function: the principle of short circuit protection is the same as 3) Note:
(1) protection IC: it is the core of the protection chip. Judge by sampling the battery voltage, send various commands to control the MOS tube and manage the cell.
(2) MOS tube: it mainly acts as a switch in the circuit of the protection board
Typical protection board circuit
Take the single section protection board circuit (dw01 + P) as an example:
Classification of protective plates
1. Classification by material
1) Gold Plated protective plate — gold plate for short
Hardware protection board
Ordinary gold-plated protective plate
Thick gold plated protective plate
Gold sinking protection plate
2) Tinned protective plate — tin plate for short
Ordinary tin plate
Lead free tin plate
2. Classification by battery
1) Single section protection board
2) Double section protection plate
3) Multi section protection board
Market capacity of protection board
The global market capacity is about 100KK / m
1) Class a market (40kk / M)
Note: for the protection of class a market, the main manufacturers of IC include Seiko, Ricoh and beauty of beauty; MOSFET
The main manufacturers are Sanyo and AO;
2) Class B market (40kk / M)
Note: the main manufacturers of protection IC in class B market include Fujing, Xinde and zhongxingwei; The main manufacturers of MOSFET include sanhewei, Huarui, Nanhai, Jiaochang and Maoda;
3) Class C Market (20KK / M)
Note: the main producers of protection IC in class C market are Shilan, heisenlin and jinweike;
The main manufacturers of MOSFET include Zhuhai Nanke, heisenlin and jinweike.