Power battery pack production process_Power battery PACK four process introduction

The power battery PACK is generally composed of five major systems.

How are these five systems assembled together to form a complete and mechanically reliable battery PACK? Rely on the assembly process.

The assembly process of PACK is actually somewhat similar to the engine assembly process of traditional fuel vehicles.

The five systems are connected together by means of bolts, nuts, ties, clamps, wire harnesses, and other connectors to form an assembly.

The power battery PACK is generally installed under the new energy car seat or under the trunk and is directly in contact with the outside world. When high-voltage electricity comes into contact with water, you can imagine the consequences of things through common sense. Therefore, when new energy vehicles wading, they need a good seal of the battery PACK.

The airtightness detection in the manufacturing process of power battery PACK is divided into two steps:

1) thermal management system-level airtightness testing;

2) PACK level airtightness detection;

The protection level system drafted by the International Electrotechnical Commission (IEC) stipulates that the power battery PACK must reach the IP67 level.

At the Shanghai Auto Show in April 2017, SAIC Passenger Motors displayed its own high-grade airtight protection technology. Put the entire PACK in the charged state into the goldfish tank and soak for 7 days. The goldfish is intact and there is no water in the PACK.

Powerless battery PACK without software is no soul.

Software flashing is also called software burning, or software filling.

The software brushing process is to brush the BMS control strategy into the CMU and BMU in the BMS in the form of code to perform data processing and analysis by the electronic control unit during battery testing and use. Then based on the analysis results, the relevant function modules in the system are issued with control instructions, and eventually the information is transmitted to the outside world.

The electrical performance testing process is the inspection process that must be done after the above three processes are completed, ie before the product goes offline.

Electrical performance testing consists of three steps:

1) Static test:

Insulation detection, state of charge detection, fast and slow charging test, etc.

2) dynamic testing;

Through the constant high current, the power battery capacity, energy, battery pack consistency and other parameters are evaluated.

3) SOC adjustment;

Adjust the SOC of the battery PACK to the factory SOC

SOC: StateOfCharge, the popular will be the remaining battery power.

With regard to the electrical performance test parameters of the battery PACK, each company actually has its own defined standard, which is different. However, the national requirements for the electrical performance of new energy vehicle power are regulated. The national standard is as follows:

"GB/T31484-2015 Power Battery Life Cycle Requirements and Test Methods for Electric Vehicles"

"GB/T31486-2015 Electric Vehicle Power Battery Performance Requirements and Test Methods"

"GB/T31467.1-2015 lithium-ion battery packs and systems for electric vehicles Part 1: Test procedures for high-power applications"

"GB/T31467.2-2015 Li-ion powered battery packs and systems for electric vehicles - Part 2: Test procedures for high-energy applications"

"GB/T31467.3-2015 Lithium-ion battery packs and systems for electric vehicles Part 3: Safety requirements and test methods"

Power battery PACK is relatively a technology-intensive industry. The assembly process of consumer electronic battery P ACK includes many links such as patching, battery welding, fixing, and testing, and it is difficult to achieve complete automation with respect to other aspects of battery manufacturing. Therefore, it is a labor-intensive industry. This is also why Asia has become a global battery PACK assembly base. Taiwan and China occupy the world's major market share in the consumer electronics battery PACK. With the rise of the mainland consumer electronics market, the mainland market share has become higher and higher. The power battery PACK will be higher in terms of automation. It will involve the automotive industry and will have higher technical requirements. It is a technology-intensive industry.

Power Battery PACK Process

As we all know, the battery PACK is the core energy source of new energy vehicles, providing the drive power for the vehicle. It mainly constitutes the battery PACK body through the envelope of the housing. The battery PACK consists of several parts, including batteries, modules, electrical systems, thermal management systems, housings, and BMS.

Icon: Battery Pack Model

It is reported that on November 24, the China Machine Center issued the "Notice on Adjusting Technical Requirements for GB/T31467.3-2015 Review" to reduce the burden on the enterprise and reduce the measured items as much as possible under the precondition of ensuring product safety. Discussed and approved by the competent authority, and adjusted the technical requirements for the review of GB/T31467.3-2015 "Lithium-ion battery packs and systems for electric vehicles Part 3: Safety requirements and test methods". The newly declared automotive products have been available since 2018. On January 1 of the year (the announcement of the 304th batch) began to implement.

Illustration: battery pack related standards

According to reports, Shenyang Power Battery Center (October 24, BMW Brilliance Shenyang Power Battery Center was officially unveiled) has become BMW's largest battery center outside of Germany. Its supplier Ningde Times President Huang Shilin said in an interview earlier, “The current state There are some thresholds for subsidy policies, such as the temporary suspension of three-cell batteries on buses and the healthy and steady growth of the industry.

It is true that China's power battery PACK business started late and its technical level is also behind that of Japan and South Korea. However, China's power battery production scale is increasing year by year, especially in 2015, the industry's growth rate is as high as 229.5%, and the capacity has also exceeded the 30 billion yuan, reaching 34.69 billion yuan, it is estimated that by 2019, the power battery PACK industry will form a 100 billion-class market.

It is understood that at present, China's power battery PACK industry market participants have three types: battery production companies, vehicle companies and professional battery PACK companies, and their market share is currently 60%, 20%, 20%.

Graphic: China Power Battery PACK Industry Market (Unit: %)

As a leading company in China's new energy vehicles, BAIC Group covers battery products with large, medium and low, high, medium and low levels, different configurations, and different battery life to meet the diverse needs of users. It is worth mentioning that the battery module of BAE New Energy adopts the standardized and modular technology, namely, the BJEV Standardized Battery Module (abbreviated as BSBM), and industry experts believe that “this will also be a future direction”.

Industry stakeholders believe that if the same standard module is used to build the battery PACK, not only can it quickly provide suitable battery packs for different models, but it can also optimize battery cooling in the structure, improve battery PACK work efficiency, reduce costs, and reduce development. cost. In addition, enterprises can ensure the consistency, safety, and reliability of battery packs as much as possible by putting them into production according to uniform production standards, making the production process more efficient.

Needless to say, high-quality power battery PACK companies need to customize R&D and design for power battery BMS solutions, thermal management, space dimensions, and structural strength based on the individual needs of depot customers' different models. According to the understanding of the electric vehicle resource network, Geely Automobile also made a corresponding breakthrough in terms of batteries. By adopting the modular design of the battery PACK, the customer has realized more possibilities. According to the relevant person in charge, "In the field of plug-in hybrid vehicles, a standardized module has been selected, and battery packs can be developed on a platform basis for different vehicle models and wheelbases, making the cost more controllable."

Compared with the domestic new energy automobile market, the competition in foreign countries is becoming increasingly fierce. The auto makers are squeezing their heads and trying to increase the mileage of their cars, so they have entered the field of battery PACKs. The latest news, Mercedes-Benz will be equipped with "modular battery packs" for the new electric buses exhibited in 2018. According to the electric vehicle resource network, the modular battery pack can be used not only on electric buses, but also when the technology is mature, it can be put on the flagship model of Mercedes-Benz, which greatly saves production and design costs.

More importantly, by using the same basic architecture to develop battery packs, the design and manufacture of batteries is as simple as building LEGO bricks. This means that the price of Mercedes-Benz's electric vehicles may also drop.

In addition, the German Mercedes-Benz will also exhibit the brand new Citaro electric car at the IAA (Hanover International Commercial Vehicle Show) in 2018. Judging from the information currently exposed, the most important feature of the pure electric version of the Citaro model is that it adopts a modular battery structure and will start producing “modular battery packs” before the end of 2018. Hartmut Schick, head of the Daimler Bus Company, said: “Our city buses will be zero-emissions and give the city's public road traffic a quiet green experience.”

Icon: Citaro, the new brand of pure electric bus in Germany

As the development of the power battery industry matures, the battery PACK modularization technology will surely become more and more mature. Relevant experts believe that there are two possible ways to improve the integration efficiency of Pack: First, optimize the internal structure design of PACK, greatly reduce the number of components inside PACK, and integrate more components and functions into modules and cabinets. On the other hand, the weight is reduced; the other is the use of lightweight materials, such as the use of aluminum or composite materials instead of high-strength steel, the use of plastic parts instead of metal parts, etc., can also reduce weight.

It is true that the development of battery PACK technology involves multidisciplinary and multidisciplinary knowledge and requires interdisciplinary technology integration. All in all, car manufacturers want to produce PACK products whose life span, stability, reliability, and safety are fully in line with the requirements of new energy vehicles, and also require a large number of engineering practices and test verification, as well as continuous optimization and upgrading of products. process.