Lithium battery module design production process and trends

Introduction of lithium battery module

Lithium battery module can be understood as a lithium-ion battery cell combined in series and parallel, plus a single battery monitoring and management devices formed after the cell and pack intermediate products. The lithium ion battery structure must be used to support, fix and protect the battery cell, which can be summarized into 3 major items: mechanical strength, electrical performance, thermal performance and fault handling ability.

Whether it can fix the position of the core and protect it from deformation that will damage its performance, how to meet the current-carrying performance requirements, how to meet the temperature control of the core, whether it can cut off the power when encountering serious abnormality, and whether it can prevent the propagation of thermal runaway, etc., will be the criteria for judging the strengths and weaknesses of lithium battery modules. For high performance lithium battery module, the solution of thermal management has been shifted to liquid cooling or phase change materials.

Lithium-ion battery pack internal connection wire is very much, manual welding operation step too many and welding, assembly and other problems; parts are very much and cause assembly difficulties, high battery failure rate, high cost.

8 characteristics of lithium battery module

A lithium battery module is a battery assembly composed of multiple lithium battery cells in accordance with a specific circuit connection. Generally speaking, lithium battery module should have the following characteristics:

1. High energy density
2. Fast charging and discharging characteristics
3. Low self-discharge rate
4. Good stability
5. Sufficient cycle life
6. Lithium battery module requires a high degree of consistency (capacity, internal resistance, voltage, discharge curve, life).
7. Lithium battery module must meet the voltage and capacity requirements of the design.
8. The cycle life of the lithium battery module is lower than the cycle life of a single cell.

Lithium battery module design and production process

The whole lithium battery module design process actually includes you have to mean the whole module design goal, integrate the details of the module design, and have a complete set of verification process of the module design, including the structure, electrical, cooling safety several parts, all of which have to be implemented in it.

The first part is divided into several design levels

To meet the needs of the vehicle equivalent to the product characteristics, it is important to divide into structure, electrical design, thermal design, safety, according to the requirements of the battery cell to give enough compression force, this compression will also be mentioned later, the entire battery cell, whether it is a soft pack or a hard shell, through a certain amount of to prevent the expansion of the battery cell, to be supported in the life of the battery to a certain extent.

In the whole lithium-ion battery pack there is also a module and tray fixation, through the pressure strip so that the module and tray for effective fixation. The important thing is the sampling line inside, and prevent the battery cell from moving inside, the whole battery cell in normal NETT working conditions in terms of heat is not serious.

We also have to consider that there may be some extreme cases, that is, the user may be at high speeds, equivalent to say long-distance driving into the fast charging state, the continuous limit of compliance, there may be a very strong heat transfer requirements here. Safety, with the module design in the middle of the cell insulation requirements, there is a strong link here.

The second part, lithium battery manufacturing process.

The most important thing is to take the core from the monomer to stacking to welding, sampling line arrangement, CMU arrangement, the whole process, equipment, about the distance, process assembly are required, this part to be with the equipment, especially when going to the volume, especially on the automated production line, there is a pretty strong demand connection here.

The third part, maintenance considerations

Because we are doing now, at the beginning of the first step is to make the product out, later with the use of the vehicle, the entire lithium battery module maintenance, especially the damage of the relevant subcomponents, how to repair the module, here with the manufacturing process, the maintenance process combined, here we talk about less.

The fourth part, module laddering utilization

Generally speaking, the lithium-ion battery pack requirements will be sorted out after the design of a module block diagram, the important thing is to connect the various parts, including electrical, structural, vehicle coupling, mechanical fixation, the electrical structure of the part of the demand are entered into the inside, so that each part of the design objectives can be clarified.

Key points of lithium battery module structure design

• Reliable structure: anti-vibration and anti-fatigue.
• Controllable process: no over-soldering, no false soldering, ensuring 100% damage-free battery cells.
• Low cost: low automation cost of PACK production line, including battery production equipment, production loss.
• Easy to dismantle: lithium-ion battery packs are easy to maintain, repair, low cost, and the battery cells can be utilized in a good way.

It is understood that, at present, the industry’s cylindrical core module grouping efficiency of about 87%, the system grouping efficiency of about 65%; pouch core module grouping efficiency of about 85%, the system grouping efficiency of about 60%; prismatic core module grouping efficiency of about 89%, the system grouping efficiency of about 70%. pouch battery core monomer energy density than cylindrical battery pack and prismatic cell has a higher promotion space, but the lithium battery module design requirements are higher, security is not easy to control, which are to structure design to solve the problem.

Future trends in lithium battery module production

With the continuous expansion of new energy vehicle market and technological progress, lithium battery module production line will have more technological trends. For example:

• Nano-coating technology: covering nano-coating on the cathode and anode in lithium ion battery can improve the life and energy density of a battery.
• High-throughput production technology: adopting process standardization and assembly line production method can significantly improve production efficiency and reduce costs.
• Artificial intelligence technology: Through data processing and analysis, intelligent production management of lithium battery module can be realized to further improve production efficiency.