Lithium Battery Pack Knowledge


In the context of double carbon, lithium batteries are favored by industries such as 3C digital products and power tools due to their high energy density, high voltage, environmental friendliness, long lifespan, and fast charging capabilities. They make significant contributions to the new energy vehicle industry. Lithium batteries can be applied in various energy storage scenarios and serve as an important power source for new energy vehicles, thus possessing enormous market potential.

Difference between Battery Cell, Battery Module, and Battery Pack:

Battery Cell: The most basic element composing battery modules and battery packs, typically providing a voltage between 3V and 4V.

Battery modules: Comprised of multiple cells assembled to form a single physical module, providing higher voltage and capacity.

Battery Pack: Typically composed of multiple battery modules assembled, along with the inclusion of a battery management system (BMS), this is the final product provided by the battery factory to the end user.

Basic Classification of Battery Packs:

Battery cells, as the core components of packs, are currently classified into three main types based on their outer shape: prismatic, cylindrical, and pouch (polymer batteries). The positive and negative electrodes are encapsulated into their respective shells through different methods.

Composition of Pack Battery Packs:

Pack battery packs mainly consist of several components, including battery modules, structural systems, electrical systems, thermal management systems, and BMS.

Battery Modules: If a battery pack is likened to a human body, the module acts as the “heart,” responsible for storing and releasing energy to power the vehicle.

Structural Systems: Mainly composed of the upper cover, tray, various metal brackets, end plates, and bolts of the battery pack, it can be considered the “skeleton” of the battery pack, providing support, mechanical impact resistance, mechanical vibration resistance, and environmental protection (waterproof and dustproof).

Electrical Systems: Mainly composed of high-voltage busbars or harnesses, low-voltage harnesses, and relays. The high-voltage harness can be seen as the “major arteries” of the battery pack, continuously delivering power from the heart of the power battery system to various components that need it, while the low-voltage harness can be seen as the “neural network” of the battery pack, transmitting real-time detection signals and control signals.

Thermal Management Systems: There are mainly four types of thermal management systems: air cooling, water cooling, liquid cooling, and phase change materials. Taking the water cooling system as an example, the thermal management system mainly consists of cooling plates, cooling water pipes, insulation pads, and thermal conductive pads. The thermal management system acts like an air conditioner for the battery pack.

BMS: Battery Management System, which can be regarded as the “brain” of the battery. It mainly consists of CMU and BMU.

CMU: Cell Monitor Unit, responsible for measuring parameters such as battery voltage, current, and temperature, as well as balancing functions. After the CMU measures these data, it transmits them to the BMU through the battery above the “neural network.”

BMU: Battery Management Unit, responsible for evaluating the data transmitted by the CMU. If the data is abnormal, it protects the battery by issuing requests to reduce the current or cut off the charging and discharging paths to prevent the battery from exceeding permissible usage conditions. Additionally, it manages the battery’s state of charge and temperature.

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