The electric vehicle and energy storage markets have been on a relentless rise, attracting an influx of newcomers and partners to the battery industry. 

For those transitioning from academia to industry or anyone new to this dynamic field, it’s essential to grasp the fundamental components of power batteries. 

Today, we’ll explore the three most crucial elements: cells, battery modules, and battery packs.

1. Cells: The Building Blocks

Cells serve as the fundamental building blocks of power batteries, typically lithium-ion batteries. These cells offer a working voltage ranging between 3V and 5V, which, although respectable, is insufficient for providing the high voltage and capacity needed to propel electric vehicles. As a result, cells are connected in series to form a battery module. Series connections elevate voltage, while parallel connections increase capacity.

There are three common types of cells:

Cylindrical Cells: These are compact, tubular batteries often seen in consumer electronics.

Prismatic Cells: These come in rectangular shapes and are typically used in portable electronics and energy storage systems.

Pouch Cells: These cells are made of flexible aluminum-plastic film and are versatile in shape and design, making them suitable for a variety of applications.

It’s essential to note that the choice between square and soft-packed cells is largely dependent on specific requirements and material properties.

2. Battery Modules: Structured Assemblies

Given that a battery pack comprises thousands of individual cells, managing them all effectively requires a structural organization. This is where battery modules come into play. Cells are initially connected and housed within frames to form these modules. Battery modules provide an additional layer of protection, shielding cells from external factors such as heat and vibration.

An example of a battery module can be found in Tesla’s electric vehicles. The Tesla battery module consists of multiple cells, offering robust energy storage and a safeguarded structure.

3. Battery Packs: The Powerhouses

Multiple battery modules are connected in series, and a battery management system (BMS) is incorporated along with cooling equipment for temperature and voltage regulation. This integration gives rise to a formidable battery pack. Essentially, a battery pack is the form in which multiple cells are installed in an electric vehicle, providing the necessary energy to power the vehicle. An instance of this configuration is the BMW i3’s battery, which contains a total of 96 cells. In this arrangement, 12 cells form a module, and eight modules combine to create the battery pack.

The table below summarizes the key distinctions between cells, battery modules, and battery packs:

Table 1: Cell vs. Module vs. Pack

Component | Function | Structure

Cell | Basic building blocks | Tubular, rectangular, or flexible shape

Module | Organized cell assemblies | Framed configuration with added protection

Pack | Integrated energy source | Multiple modules with the management system

4. Battery Pack Assembly: A Comprehensive Process

In general, assembling a battery pack is a systematic process that involves moving from cells to modules and eventually to the battery pack. Each step plays a crucial role in ensuring the efficient operation of the battery system.

In conclusion, understanding these fundamental components—cells, battery modules, and battery packs—lays the groundwork for navigating the intricate world of power batteries. As the electric vehicle and energy storage sectors continue to advance, this knowledge becomes increasingly essential for both newcomers and industry experts alike.