Introduction to the production process of 6F22 battery

1. Assembly process

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? It depends on the assembly process.

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

The five major systems are connected together through bolts, nuts, cable ties, clamps, wiring harness nails and other connectors to form an assembly.

Power battery pack production process flow_Introduction to the four major processes of power battery PACK

2. Air tightness detection process

Power battery PACK is generally installed under the seat or trunk of new energy vehicles, and is directly in contact with the outside world. Once high voltage electricity comes into contact with water, you can imagine the consequences through common sense. Therefore, when new energy vehicles wade through water, the battery PACK needs to have good sealing.

The airtightness test in the manufacturing process of power battery PACK is divided into two links:

1) Airtightness test at the thermal management system level;

2) Airtightness test at the PACK level;

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 Vehicle showed off its awesome high-level airtightness protection technology. The entire PACK in the charging state was placed in a goldfish tank and soaked for 7 days. The goldfish was intact and no water entered the PACK.

3. Software flashing process

A power battery PACK without software is soulless.

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

The software flashing process is to flash the BMS control strategy into the CMU and BMU in the BMS in the form of code, so that the collected battery status information data will be processed and analyzed by the electronic control unit during battery testing and use, and then control instructions will be issued to the relevant functional modules in the system according to the analysis results, and finally information will be transmitted to the outside world.

Power battery pack production process flow_Introduction to the four major processes of power battery PACK

4. Electrical performance testing process

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

Electrical performance testing is divided into three links:

1) Static test:

Insulation detection, charging status detection, fast and slow charging test, etc.;

2) Dynamic test;

Evaluate the parameters such as power battery capacity, energy, and battery pack consistency through a constant large current.

3) SOC adjustment;

Adjust the SOC of the battery PACK to the factory SOC

SOC: StateOfCharge, commonly known as the remaining power of the battery.

Regarding the electrical performance testing parameters of the battery PACK, each company actually has its own defined standards, which are different. However, the state has regulations on the electrical performance requirements of new energy vehicle power, and the national standards are as follows:

GB/T31484-2015 Requirements and test methods for cycle life of 6F22 battery for electric vehicles

GB/T31486-2015 Requirements and test methods for electrical performance of 6F22 battery for electric vehicles

GB/T31467.1-2015 Lithium-ion power battery packs and systems for electric vehicles Part 1: High-power application test procedures

GB/T31467.2-2015 Lithium-ion power battery packs and systems for electric vehicles Part 2: High-energy application test procedures

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

Power battery PACK is relatively technology-intensive. The assembly process of consumer electronics battery PACK includes multiple links such as patching, battery welding, fixing, and testing. Compared with other links in battery manufacturing, it is difficult to achieve complete automation, so it is a labor-intensive industry. This is also an important reason why Asia has become the global battery PACK assembly base. Taiwan and the mainland occupy the main global market share in consumer electronics battery PACK. With the rise of the mainland consumer electronics market, the mainland market share has been increasing. The power battery PACK will have a higher degree of automation, involving the automotive field, and the technical requirements will be higher. It is a technology-intensive industry.

As we all know, the battery PACK is the core energy source of new energy vehicles, providing driving power for the whole vehicle. It mainly forms the main body of the battery PACK through the shell envelope. The battery PACK mainly consists of battery cells, modules, electrical systems, thermal management systems, shells and BMS.

1. The state has issued relevant standards to achieve healthy and sustainable development of the industry

It is reported that on November 24, China Machinery Center issued the "Notice on Adjusting the Technical Requirements for the Examination of GB/T31467.3-2015". In order to reduce the burden on enterprises and reduce the actual test items as much as possible under the premise of ensuring product safety, after discussion by the Automobile Product Technical Committee and approval by the competent authorities, the technical requirements for the examination of GB/T31467.3-2015 "Lithium-ion Power Battery Packs and Systems for Electric Vehicles Part 3: Safety Requirements and Test Methods" are adjusted. Newly declared automobile products will be implemented from January 1, 2018 (Announcement No. 304).

It is revealed that the Shenyang Power Battery Center (the Brilliance BMW Shenyang Power Battery Center was officially unveiled on October 24) has become BMW's largest battery center outside of Germany. Huang Shilin, president of its supplier CATL, said in an interview earlier that "the current state has set some thresholds for subsidy policies, such as temporarily suspending the use of ternary batteries in buses, which is also for the healthy and stable development of this industry."

2. China's battery PACK production capacity is gradually expanding

Admittedly, my country's power battery PACK business started late and its technical level is also lagging behind Japan, South Korea and other countries, but my country's power battery production scale is growing year by year, especially in 2015, the industry growth rate was as high as 229.5%, and the capacity also exceeded 30 billion yuan, reaching 34.69 billion yuan. It is expected that by 2019, the power battery PACK industry will form a market of 100 billion yuan.

It is understood that at present, there are three types of market participants in my country's power battery PACK industry: battery cell manufacturers, vehicle manufacturers and professional battery PACK companies, and their current market shares are 60%, 20% and 20% respectively.

As a leading enterprise in China's new energy vehicles, BAIC Group covers battery products of different levels, configurations and endurances, meeting the diversified needs of users. It is worth mentioning that BAIC New Energy's battery module adopts standardized and modular technology, namely the standardized battery module (BJEV Standardized Battery Module, referred to as BSBM). Industry experts believe that "this will also be a direction in the future."

Industry experts believe that if the same standard module is used to build a battery PACK, it can not only quickly provide suitable battery packs for different models, but also optimize the heat dissipation of the battery in the structure, improve the working efficiency of the battery PACK, reduce costs, and reduce development costs. In addition, enterprises can also maximize the consistency, safety and reliability of the battery pack by putting it into production according to unified production standards, making the production process more efficient.

Undoubtedly, high-quality power battery PACK companies need to carry out customized research and development and design of power battery BMS solutions, thermal management, space size, structural strength, etc. based on the personalized needs of different models of car factory customers. According to the Electric Vehicle Resource Network, Geely Auto has also made corresponding breakthroughs in batteries. By adopting the modular design of battery PACK, it has realized more possibilities for customers. The relevant internal person in charge introduced that "in the field of plug-in hybrid models, standardized modules are selected, and battery packs can be developed for different models and wheelbases to make costs more controllable."

3. Foreign countries use modular battery packs to improve the range

Compared with the domestic new energy vehicle market, foreign competition is also becoming more and more fierce. Car companies are trying their best to improve the range of cars, so they have entered the battery PACK field. The latest news is that Mercedes-Benz will equip the new electric bus exhibited in 2018 with "modular battery packs". According to the Electric Vehicle Resource Network, modular battery packs can not only be used in electric buses, but also can be transferred to Mercedes-Benz's flagship models after the technology matures, greatly saving production and design costs.

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

In addition, Germany's Mercedes-Benz will also exhibit the new pure electric bus Citaro model at the 2018 IAA (Hannover International Commercial Vehicle Show). From the information currently exposed, the biggest feature of the pure electric version of the Citaro model is that it adopts a modular battery structure, and the "modular battery pack" will begin production before the end of 2018. Hartmut Schick, head of Daimler Bus Company, said: "Our city buses will achieve zero emissions and provide a quiet and green experience for public road traffic in the city."

With the gradual maturity of the development of the power battery industry, the modular technology of battery PACK will become more and more mature. Relevant experts believe that there are two feasible ways to improve the integration efficiency of the Pack: one is to optimize the internal structural design of the PACK, greatly reduce the number of components inside the PACK, and integrate more components and functions into the module and box to reduce weight; the other is to use lightweight materials, such as aluminum profiles or composite materials instead of high-strength steel, plastic parts instead of metal parts, etc., which can also reduce weight.

It is true that the development of battery PACK technology involves knowledge from multiple disciplines and fields, and requires cross-disciplinary technology integration. In short, if car companies want to eventually mass-produce PACK products that fully meet the requirements of new energy vehicles in terms of life, stability, reliability, and safety, they still need a lot of engineering practice and testing verification, as well as a process of continuous product optimization and upgrading.

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