CR1625 battery

Decomposition of the current technical level of domestic power CR1625 battery companies

On the premise of ensuring safety, improving energy density, reducing processing costs, and improving product consistency are topics of widespread concern in the power lithium-ion battery industry. The processing cost curve is constantly fluctuating, and product consistency is not easy to quantify. If you want to evaluate the technical level of power lithium-ion battery companies, comparing the energy density of batteries is the most intuitive way.

This article takes ternary batteries as an example, according to the three packaging systems of square shell, cylindrical and soft pack, and refers to the views of some people, without satellites, and decomposes the current technical level of domestic power lithium-ion battery companies based on energy density as the standard.

Square shell: CATL and BYD may not be behind

Official data show that the energy density of CATL's square shell battery cells has reached 240Wh/kg at this stage, and the technical plan is to increase the energy density of batteries to 300Wh/kg before 2020.

While improving the energy density through 811 ternary positive electrode + silicon/carbon mixed negative electrode, the cycle, high temperature performance, cost, safety, etc. must be sacrificed, and the processing technology and environmental requirements are also relatively harsh. According to an insider, the energy density of the square shell battery cells supplied by CATL in large quantities in 2017 was between 190 and 210Wh/kg, and it is likely to increase to 210 to 230Wh/kg in 2018.

As early as the beginning of 2017, CATL launched the "New Generation of Lithium-ion Power Lithium-ion Battery Industrialization Technology Development" project to develop lithium-ion power lithium-ion batteries with high-nickel ternary materials as positive electrodes and silicon-carbon composites as negative electrodes. In 2017, CATL's total output was 17.09Gwh, and the new version of the prospectus just released shows that when the Huxi Lithium-ion Power Lithium-ion Battery Processing Base project reaches full production, CATL will increase its output by 24GWh, and the total output will reach 41.09GWh.

According to an insider of BYD, the energy density of BYD's large-scale mass-produced battery cells is 220Wh/kg at this stage, and the goal is to achieve 300Wh/kg before 2020. Today, BYD's total output of power lithium-ion batteries is 16GWh, of which iron phosphate lithium-ion batteries account for 9GWh and ternary lithium-ion batteries account for 7GWh.

Internationally, square shell cells are also the main products of Samsung SDI. In 2017, Zheng Shixiong, vice president of Samsung SDI Co., Ltd., publicly stated that the energy density of Samsung SDI's power lithium-ion batteries is currently 250Wh/kg, and it is expected to reach the goal of 350Wh/kg in 2023. Perhaps Samsung has really achieved large-scale mass production of 250Wh/kg square shell cells in 2017, but it is estimated that it may use NCA ternary positive electrode materials.

There are many types of square shell batteries. According to customer requirements, battery companies can customize capacity, shape and size. Considering the differences in the formulation of positive and negative electrode materials, the energy density between square shell cells of the same specification is more comparable. The gap in cell energy density between leading square shell power lithium-ion battery companies at home and abroad may be very small. Perhaps from this technical condition alone, my country may not lag behind too much.

Cylindrical: Can BAK surpass Panasonic?

As one of the few companies in China that focuses on cylindrical power lithium-ion batteries, BAK told the First Electric Network that the energy density of its 2.75Ah power lithium-ion battery cell (18650) has reached 240Wh/Kg, and plans to achieve 300Wh/kg in 2020.

At the same time, BAK is also committed to the research and development of high-energy-ratio 21700 cylindrical power lithium-ion battery cells. Officials revealed that compared with 18650 products, the single energy density of BAK 21700 has increased by 35% (reaching the level of 324Wh/kg?), and it currently has mass production capacity and is expected to achieve large-scale processing in 2018.

BAK's two major processing bases in Shenzhen and Zhengzhou have a total annual output of 8GWh; in 2018, the output will be expanded to 12GWh; it is expected that by 2020, BAK's total annual output will reach 20GWh.

According to the information released by Tesla in 2017, the energy density of Panasonic's mass-produced NCA18650 cylindrical power lithium-ion battery monomer is about 250Wh/kg, while the energy density of 21700 monomer has reached 300Wh/kg. If BAK can mass-produce 21700 cylindrical batteries in 2018, its energy density can surpass Panasonic's 2017 level, which is nearly 8% higher.

Is this true? In 2018, Panasonic has not publicly announced the latest commercial technology progress. If BAK can really achieve mass production of 324Wh/kg cylindrical cells in 2018, then this may become the world's highest energy density mass-produced power lithium-ion battery.

Soft pack: Perhaps more scientific research significance

Soft pack, relative to hard shell (square shell, cylinder), is a common packaging method for batteries, so it is parallel to cylinder and square.

The energy density of the battery cells currently supplied by Kane New Energy in mass production is 220Wh/kg, and the products in 2018 will reach 250Wh/kg. As of the end of 2017, Kane New Energy's total output was 2GWh, and it will expand to 6GWh by the end of 2018.

Guoxuan High-tech also disclosed in the record of investor relations activities that the company's undertaking of the 300Wh/kg high energy density major scientific and technological project of the Ministry of Science and Technology is currently progressing smoothly. It has developed a ternary 811 soft-pack battery cell with an energy density of 302Wh/kg. It has begun to build a pilot line for related products and plans to start building a production line in 2019.

Tian Shuo, general manager of Beijing Keyi Power Technology Co., Ltd., explained that the company, which is responsible for the major project of the Ministry of Science and Technology on power lithium-ion battery cells, has its own reasons for choosing ternary soft packs. "To complete a 300Wh/kg battery cell, a soft pack is definitely much easier than a square shell."

Soft-pack batteries have poor mechanical strength, and the requirements for grouping process and thermal management matching are relatively high. The bMS design of the relevant vehicle company is somewhat challenging. Moreover, some core components are not domestically produced, but with the maturity of the industrial chain, the prospect of large-scale localization is expected.

It is easier to make a big promise than to do real work

Although major battery companies have their own main products, in terms of research and development, companies will be involved to varying degrees in the three different systems of batteries: square shell, cylindrical and soft pack. No one will hang on a tree. Perhaps the market determines the type of products that the company promotes at this stage, but in the long run, there will not be a single technical route.

In today's power lithium-ion battery industry, news such as capital injection and company mergers and acquisitions are emerging in an endless stream, and various battery concepts and laboratory breakthroughs are constantly breaking through. News such as "Charging for 1 minute and driving 800km" frequently swipes the screen. Putting aside commercialization and talking about technology is rogue. Each technical route has its own advantages and disadvantages. In the end, it is still the company's own strengths, market choices, and products that speak.

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