What is the difference between a lithium-ion battery PCM/PCB and a BMS?

What is a lithium-ion battery PCM (protection circuit module) / PCB (protection circuit board)?

Lithium-ion battery PCM/ PCB can play the role of charge/discharge protection for series and parallel battery pack, and at the same time can detect the over-voltage, over-current, over-temperature, under-voltage, short-circuit status of each single battery in the battery pack to prolong the battery life and avoid battery damage caused by over-discharge. Lithium battery PCM / PCB is an indispensable part of lithium battery.

The lithium-ion battery PCM / PCB also has a balanced protection function, which has two modes of energy consumption and energy conversion.

Energy dissipation equalization refers to the use of a resistor in a series of batteries with high power or voltage to consume excess power. Energy-consuming balancing is divided into balancing during charging, fixed-point voltage balancing, and static automatic balancing.

Equalization when charging: When charging, when the voltage of any battery is higher than all the average voltages, the lithium-ion battery PCM / PCB starts equalization protection.

Voltage fixed-point equalization: The lithium-ion battery PCM / PCB is set to start equalization at a voltage point, which is only performed at the battery charging end, and the equalization time is shorter.

Static automatic equalization: It is carried out during charging or discharging, even if the battery is in a static state, when the voltage is inconsistent, the lithium-ion battery PCM / PCB will start the equalization protection until the voltage remains consistent.

The energy transfer method is to transfer a large-capacity battery to a small-capacity battery in the manner of energy storage, to detect the capacity of the battery for balance, which is divided into capacity constant balance and fixed-point balance.

What is a lithium-ion battery BMS (battery management system)?

The battery BMS has the function of measuring the battery voltage, and also includes the battery protection function, battery balancing function, battery reserve function, energy measurement function, network communication function and so on. The battery management system can prevent abnormal conditions such as overdischarge, overcharge, and overtemperature.

Since the lithium battery may damage the battery performance under severe overcharge and overdischarge conditions, or even cause an explosion hazard, the battery BMS exists to monitor, protect, and balance the lithium battery, thereby improving the working efficiency of the lithium battery.

 

Differences between lithium battery PCM/PCB and BMS

Both the lithium-ion battery PCM / PCB and the battery BMS protect the lithium battery. The differences between them are:

1. Lithium-ion battery PCM / PCB is composed of IC, MOS tube and resistance and capacitance components, and is an important component of lithium battery. The battery BMS can be edited and comes with its own battery management software, which is relatively smarter, equivalent to the brain of a lithium battery, which plays a role in management and control.

2. The lithium-ion battery PCM / PCB plays an important role in the field of 3C lithium batteries and low-level power batteries, and the battery BMS is applied in the field of high-level power batteries.

3. The battery BMS system operates better than the lithium-ion battery PCM / PCB, but its performance at low temperatures is unstable.

In summary, the role of lithium-ion battery PCM / PCB and BMS is so great. Therefore, the quality inspection of lithium-ion battery PCM / PCB and BMS is very important, and the selection of high-quality and high-precision test system is the key. Xiamen WinAck's lithium-ion battery PCM test equipment / PCB tester for battery pack and BMS test system have been tested by the market and are widely used. They are a good choice for lithium battery assembly factories.