Lithium batteries, as high-voltage batteries, are favored by industries such as 3C digital and electric tools due to their high energy density, environmental protection, long lifespan, and fast charging. Their contribution to the new energy vehicle industry is particularly outstanding.
Next, we will help you understand the classification, composition, process flow, and production line of lithium-ion power battery packs.
Basic introduction of lithium-ion power battery pack:
Classification of lithium-ion power battery packs:
1. What is a lithium-ion power battery pack
General differences between lithium battery cells, modules, and lithium-ion power packs:
Battery cell: the Urelement that constitutes the battery lithium-ion power pack and battery lithium-ion power pack. Generally, the voltage available is 3v-4v;
Lithium-ion battery: A physical module formed by the aggregation of multiple monomers, providing higher voltage and capacity.
Battery lithium-ion power pack: Generally composed of multiple battery lithium-ion power packs. At the same time, a Battery management system (BMS) is added, which is the final product provided by the battery factory to users.
As the core components of lithium-ion power battery packs, they are currently mainly divided into three categories based on their shape: prismatic shells, cylindrical bodies, and flexible lithium-ion power battery packs (polymer batteries). The positive and negative electrodes are encapsulated in corresponding shells in different ways.
2. Battery module
By assembling a single battery and connecting the batteries in series and parallel through the bus, screw welding, resistance welding, Ultrasonic welding, ultrasonic aluminum wire welding, and laser welding can be used. Considering the production output, efficiency, and internal resistance of connection points, laser welding is the first choice for many battery manufacturers at present.
Composition of lithium-ion power battery pack:
It mainly includes battery modules, institutional systems, electrical systems, thermal management systems, and BMS.
1. Battery module
The battery module is responsible for storing and releasing energy to provide power for the car.
2. Mechanism system
Mainly composed of a battery lithium-ion power pack cover, tray, various metal brackets, end plates, and bolts, it plays a supporting, anti-mechanical impact, mechanical vibration, and environmental protection (waterproof and dustproof) role.
3. Electrical system
Mainly composed of high-voltage jumpers or high-voltage harnesses, low-voltage harnesses, and relays. The high-voltage wiring harness can be seen as the "artery" of lithium-ion power battery packs, continuously transmitting the heart power of the power battery system to various necessary components.
The low-voltage wiring harness can be seen as a "neural network" for lithium-ion power battery packs, which transmits real-time detection and control signals.
4. Thermal management system
There are four main 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 is mainly composed of a cooling plate, cooling water pipe, heat insulation pad, and Thermally conductive pad.
5. BMS
Battery management system. It mainly consists of CMU and BMU.
CMU: Battery monitoring unit, responsible for measuring parameters such as voltage, current, and temperature of the battery, as well as balancing functions. When the CMU measures these data, it transmits the data to the BMU through the battery "neural network" mentioned earlier.
BMU: Battery management unit Battery management unit.
It is responsible for evaluating the data transmitted by the CMU. If the data is abnormal, it will protect the battery, issue a request to reduce current or cut off the charging and discharging path to prevent the battery from exceeding the allowed usage conditions, while also managing the power and temperature of the battery.
Based on the previously designed control strategy, determine the parameters and states that need to be alarmed, and send the alarm information to the vehicle controller, ultimately conveying it to the driver. The following are the top ten Battery management system suppliers.
Process flow:
The lithium-ion battery power pack is the core energy source of new energy vehicles, providing driving power for the entire vehicle. As the core component of new energy vehicles, its quality directly determines the performance of the entire vehicle. Lithium battery manufacturing equipment is generally divided into three types: front-end devices, mid-range devices, and back-end devices.
The accuracy and automation level of equipment will directly affect the production efficiency and consistency of products. Although the types of cells and modules are different, the composition and process of lithium-ion power battery packs are generally the same. Mainly divided into assembly process, airtightness testing process, software writing process, electrical performance testing process, etc.
Introduction to the production line:
During the assembly process of lithium-ion power battery packs, there are many flexible circuits and clamping fasteners. The difficulty of automation is high, and the input-output ratio is not high. Therefore, the automation level of backend devices will be lower than that of the front and middle stages, but it is compatible with the three types of lithium-ion power pack batteries in cylindrical, prismatic shells, and soft lithium-ion power packs.
Job positions that may require automation:
● The lower shell automatically goes online
The module automatically goes online and enters the shell
● Fix and tighten the module
● Thread and tighten the upper cover
Automatically apply A/B type thermosensitive adhesive (according to the process).
Automatically apply a sealant (according to the process).
● Finished product offline
In addition, some people may suggest that automatic methods are also required for copper plate installation and screw tightening, air tightness testing, and EOL testing. This situation is relatively rare and stability is difficult to guarantee.
There are two main operating methods for the batch production equipment of the backend lithium-ion power battery pack production line:
1. AGV+assembly trolley
In the past, it was mainly used in automobile factories, but now battery factories are gradually promoting this model
2. Conveyor line+tray mode
Roller conveyor line/Roller friction line/Multichain conveyor line
Summary:
With the gradual maturity of the power battery industry, the modular technology of lithium battery packs will also become increasingly mature. The development of lithium-ion power battery pack technology involves knowledge from multiple disciplines and fields, requiring interdisciplinary technology integration.
In summary, automotive companies, including the top ten power battery companies, need to conduct extensive engineering practice and experimental verification to produce power battery pack products that fully meet the requirements of new energy vehicles in terms of lifespan, stability, reliability, safety, and other aspects. And the continuous optimization and upgrading process of the product.
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