battery protection board basic knowledge

Recently many battery engineers are looking for lithium battery protection knowledge, this article basic knowledge of lithium battery protection board updated version is the latest version of the most comprehensive, it includes multiple protection plate speak, original ancestor lithium battery protection board, lithium battery protection board components, etc., make electronic engineering at a glance of eye view the basic knowledge of lithium battery protection board updated version, such as to be as follows:

One, the original ancestor of lithium battery protection plate, that is the origin.

1, lithium battery (rechargeable) need protection, is determined by its own characteristics. Because the material of the lithium battery itself determines that it cannot be overcharged, over discharge, over current, short circuit and ultra-high temperature charge and discharge, so the lithium battery lithium battery components always follow a delicate protective plate and a piece of current protector.

2, lithium battery protection board function is usually performed by protection circuit board and PTC current device coordination, protective plate is composed of electronic circuits, and 40 ℃ to + 85 ℃ under the environment of time accurate monitoring batteries voltage and circuit current and the control current loop in time on and off; PTC prevents severe battery damage at high temperatures.

Ii. Components of lithium battery protection board

1,Lithium battery protection board usually includes control IC, MOS switch, resistor, capacitor and auxiliary devices FUSE, PTC, NTC, ID, memory and so on. The control IC, in all normal circumstances to control the MOS switch conduction, so that the cell and the external circuit conduction, and when the cell voltage or circuit current exceeds the specified value, it immediately control MOS switch off, to protect the safety of the lithium battery cell.

2, the PTC devices of macromolecule polymer material, through strict process, by the polymer resin matrix and the distribution in the conductive particles, under normal circumstances, the conductive particles constitute a conductive path in the tree ester, device is characterized by low impedance, circuit has the over current occurs, the large current flows through PTC produce heat to make polymer resin matrix volume tympanitis, thus to cut off the connection between the conductive particles, the over-current protection of circuit. When the fault is removed, it can be automatically restored to the initial state to ensure the normal operation of the circuit.

Iii. Brief introduction of 18650 lithium battery protection board

1. Resistance: current limiting and sampling;

2. Capacitance: for dc, the resistance value is "infinity"; for ac, the resistance value is close to zero. The voltage at both ends of the capacitor cannot be suddenly changed, which can play the role of transient voltage stabilization and filtering.

3, FUSE: FUSE, overcurrent protection;

4, PTC: PTC is the abbreviation of Positive temperature coefficient, meaning Positive temperature coefficient resistance, (the higher the temperature, the higher the resistance value), can prevent the battery high temperature discharge and unsafe large current, namely the over-current protection.