Definition Of Battery Protection Board

The protection function of lithium batteries is usually completed by the protection circuit board and current devices such as PTC or TCO. The protection board is composed of electronic circuits, which can accurately monitor the voltage and charge and discharge of the battery cells at all times in the environment of -40°C to +85°C. The current of the loop can instantly control the on-off of the current loop; PTC or TCO can prevent bad damage to the battery in a high temperature environment.

The protection board usually includes control IC, MOS switch, precision resistor and auxiliary device NTC, ID memory, PCB, etc. Among them, the control IC controls the MOS switch to turn on when everything is normal, so that the cell communicates with the external circuit, and when the cell voltage or loop current exceeds the specified value, it immediately (tens of milliseconds) controls the MOS switch to turn off, Protect the safety of cells.

NTC is the abbreviation of Negative temperature coefficient, which means negative temperature coefficient. When the ambient temperature rises, its resistance value decreases. Use electrical equipment or charging equipment to respond in time and control the internal interruption to stop charging and discharging.

ID memory is often a single-line interface memory, ID is the abbreviation of Identification, which means identification, and stores information such as battery type and production date. It can be used to limit the traceability and application of products.

PTC is the abbreviation of English Positive Temperature Coefficient, which means positive temperature coefficient. In the profession, the positive temperature coefficient device is usually referred to as PTC. In battery products, PTC can prevent the occurrence of high temperature discharge and unsafe high current. According to the voltage, current density characteristics and application environment of the battery, there are special requirements for PTC.

PTC is a very important component in battery module products, and it plays an important role in the safety of batteries. Its own performance and quality are also an important factor in the performance and quality of battery packs.

When the protection board protects a single cell, the design of the protection board will be relatively simple, and the technicality is that, for example, the voltage platform problem that needs to be paid attention to in the design of the power battery protection board, the power battery is often required to have a large platform voltage in use. , so when designing the protection board, try to make the protection board not affect the voltage of the discharge of the cell, so that the requirements for the control IC, precision resistors and other components will be very high. Generally, domestic ICs can meet the requirements of most products, and imported products can be used in special cases. Current sampling resistors need to use JEPSUN resistors to meet the requirements of high precision, low temperature coefficient, and no inductance. For the design of multi-cell protection board, there are higher technical requirements, and products with different degrees of complexity are designed according to different needs.