The Development Of Soft-packed Batteries Is Elusive. Is The Domestic Laminated Device Coming Out Of The “surrounding City”?

- Nov 05, 2019-

The soft-packed battery that was once placed on high hopes seems to be in the mud in the domestic electric vehicle market.

With the advantages of high energy density, high safety, flexible design and relatively small internal resistance, the growth momentum of soft-pack power batteries has been obvious in the past two years, and many related companies are also infinite.

But after 2019, the situation has changed. According to the GGII data, the installed capacity of domestic soft-packed batteries reached 2.63GWh in the first half of 2019, accounting for about 8% of all power battery installed capacity, which is nearly 6% lower than the overall proportion of 13.4% in 2018. percentage point.

What is more obvious is that many of the leading soft pack battery companies have also seen a significant decline in the installed capacity ranking.

Behind the decline in the volume of flexible packaging, the reasons are complicated, both the choice of car products and the fierce competition in the power battery industry. One of the most important factors that cannot be ignored is the capacity of soft pack battery companies.

The production capacity is constrained, and the core equipment in the manufacturing process is not efficient and bears the main responsibility. Laminated devices are one of them.

Compared with the winding process adopted by the prismatic battery, the lamination process used in the flexible battery requires more control parameters, relatively complicated processes, more difficult structures, better cell yield, superior rate, equipment stability, and improved utilization rate. More difficult.

With a very graphic analogy, a laminate is a piece of cloth that is first cut into strips, and then stacked accurately and accurately, requiring no deviation. Winding directly rolls the cloth, and the deviation is within a certain range. The difficulty of both is definitely not at the same level.

The gap in this process is directly reflected in the efficiency and performance of the equipment, which ultimately affects the production line input and capacity efficiency. This even allowed a company that cuts into the power battery field from the car company to spare no expense to invest in the development of laminated devices.

From the perspective of efficiency dilemma, the efficiency of domestic Z-type single-station lamination machines is generally 1s/pcs, and the foreign Japanese and Korean roll stacks are 0.17s/pcs. Among them, the double-cam structure single-station lamination machine used in domestic Zhongtian and automation equipment has an efficiency of 0.6s/pcs, the double-position can be as high as 0.25s/pcs, and can be mass-produced.

Comparing the data, it can be seen that there is a gap in the efficiency of the domestic lamination machine. However, in other respects, the advantages of domestic equipment are more obvious, such as high cost performance, strong compatibility, and good after-sales service. The market has basically replaced Japan and South Korea.

There are three main reasons for the difference in equipment at home and abroad. First of all, foreign Japanese and Korean equipment invested in lithium batteries earlier. Under the protection of patents and intellectual property rights, the lamination process selected is different from that in China. In the foreign lamination process, the negative electrode and the separator are first cut into a unit for lamination, and then the positive electrode is wound into a cell.

In order to circumvent patent law litigation, the main use of hot composite and Z-shaped lamination process is roughly the positive and negative electrodes. The diaphragm is directly laminated after being cut, and then made into a battery core and then hot pressed and glued. The domestic lamination process is relatively complicated, requires high equipment, and is limited in terms of production efficiency.

Among them, the representative enterprise of the thermal composite lamination process is the pilot intelligent, Jiyang Automation; the Z-shaped lamination process represents the enterprise is super industry precision and Zhongtian and automation.

Second, battery model compatibility. Affected by the new energy market, domestic battery companies generally require that the laminated device be compatible with at least six different types of batteries. Foreign Japanese and Korean devices only focus on one or two battery models. The more compatible the automation equipment is, the higher the cost of doing it. Under the same conditions, compared with foreign countries, domestic equipment is highly compatible, and naturally it is relatively poor in terms of stability and utilization rate.

Finally, domestically produced equipment focuses on grabbing market share, focusing on customer experience such as cost performance and after-sales service. Foreign Japanese and Korean equipment will take the high-end route and only serve battery companies in specific fields.

Throughout the 2019 domestic laminated film market, the focus is mainly on the leading or intelligent equipment, such as pilot intelligence, super industry precision, Greene, Wintech, Zhongtian and Automation, Xinyu Intelligent (in no particular order). Equipment company.

In fact, lithium battery equipment is heavily dependent on the development of power batteries. As far as the development of the lamination machine equipment is concerned, the market prospect depends on the battery companies that have obtained the major orders.

There is a kind of play in the industry, the battery company is called the big party, and the equipment company is the small party. Therefore, the battery manufacturers mainly supplied by the equipment account for a large market share, and the market share of equipment enterprises is naturally high. Obviously, in the future, due to the head effect of battery companies, the market concentration of laminated devices will increase, of course, there will be more technical challenges.

For the technical challenges of the lamination machine, domestic equipment companies such as Li Yuanheng, Chaoye Precision, Zhongtian and Automation are constantly carrying out technological innovation and iteration.

Li Yuanheng uses a fully automatic laminated power battery assembly line to achieve full automation process docking and improve production efficiency. It mainly includes the stacking of the stacking segments, the size inspection, the thickness inspection, the X-Ray inspection, the stacking tape, the extreme group pre-welding, the pole group cutting, the short circuit test, the connecting piece and the pole group ultrasonic end Welding, top cover coding, laser welding of cover plate and connecting piece, core, package insulation, pole set, laser pre-spot welding, laser peripheral welding, short-circuit test, leak detection and production process of this section of production line logistics.

Lin Wansheng, chairman of Chaoye Precision, regards the section after the cutting of the pole piece as a wound. He believes that the lamination process is insufficient in the protection of the wound during the process of transferring and stacking the pole piece, and the wound is in an uncontrollable state, which leads to the safety of the later battery core. Sex, consistency, yield, and poor rate.

In response to this development, the punching and stacking machine can reduce the process transfer between the slice and the lamination, reduce the uncontrollable time of the wound, the degree of automation is high, the alignment and consistency of the cell are high, and mass production has been realized.

Zhongtian and Automation have developed a fully automatic splicing machine that uses laser cutting to save operating costs. It is compatible with different pole pieces and can be folded instantly, with a lamination speed of 0.25 sec/piece.

For dust, use vacuum to vacuum, brush dust, bag dust and plasma air knife to remove dust to control dust.

In terms of reliability, the motion module has a fixed positioning pin, and the transmission part has its own feedback value for real-time monitoring. In terms of equipment operation, the manual reduction is 2/3, and the floor space is reduced by 1/2, which realizes the miniaturization and automation of equipment.

All in all, the lamination machine has a complicated structure, many parameters to be controlled, and a complicated process, mainly concentrated in four aspects:

Production efficiency: Production is subject to process processes and equipment structures. The current solution is to increase the number of stations, control the incoming materials, optimize the structure layout, and engage in the all-in-one mode.

Cell core film: During the lamination process, more single chips and bad products are not effectively screened. The solution is to use more sophisticated visual sensor detection to directly eliminate bad products, while controlling the quality of incoming materials and reducing the chance of misjudgment.

Lamination unit alignment: Optimize the structure of the device, improve the machining accuracy of the machined parts, improve the accuracy of the CCD camera source, and pay attention to details when assembling and debugging.

Tail glue: After the battery core is folded, the tail glue is not enough, which affects the performance of the battery. Generally, vacuum rod adsorption is adopted, and the quality of the glue is stabilized as much as possible by the roll pressing method, so that the surface of the battery core is not wrinkled and is not damaged.

It is worth noting that at the 2019 High-Tech Lithium & Electric Vehicle Annual Meeting held on December 16-18, many companies including Li Yuanheng and Chaoye Precision will share the latest in soft-pack battery manufacturing. Progress and technology trends.