On the premise of ensuring safety, improving energy density, reducing production costs, and improving product consistency are topics of widespread concern in the power battery industry. The production cost curve is constantly fluctuating, and product consistency is not easy to quantify. To evaluate the technical level of power battery companies, comparing the energy density of batteries is the most intuitive method.

This article takes the ternary battery as an example. According to the three packaging systems of square shell, cylinder and soft package, referring to the views of some people, the current technical level of domestic power battery companies is analyzed based on energy density.

▌Fang shell: Ningde era and BYD, maybe not behind

How to evaluate the technical level of domestic power battery cells?

Official data show that the energy density of square shell cells in the CATL era has reached 240Wh/kg. The technical plan is to increase the cell energy density to 300Wh/kg before 2020.

While increasing the energy density through the 811 ternary positive electrode + silicon/carbon hybrid negative electrode, the cycle, high temperature performance, cost, safety, etc. must be sacrificed, and the production process and environmental requirements are relatively harsh. People familiar with the matter revealed to the first electric network that the energy density of square shell batteries supplied in large quantities by CATL in 2017 is between 190-210Wh/kg, and it is likely to increase to 210-230Wh/kg in 2018.

As early as the beginning of 2017, CATL started the "New Generation of Lithium-ion Power Battery Industrialization Technology Development" project to develop lithium-ion power batteries with high nickel ternary materials as the positive electrode and silicon-carbon composite as the negative electrode. In 2017, the total production capacity of CATL was 17.09Gwh, and the new version of the prospectus just announced shows that when the lithium-ion power battery production base project in Huxi reaches production, CATL will add 24GWh of new capacity, and the total capacity will reach 41.09 GWh.

And BYD insiders broke the news that the energy density of BYD's mass production of batteries at this stage is 220Wh/kg, and the goal is to achieve 300Wh/kg before 2020. Today, BYD’s total power battery capacity is 16GWh, of which lithium iron phosphate batteries account for 9GWh, and ternary lithium batteries account for 7GWh.

Internationally, square shell batteries are also the main products of Samsung SDI. In 2017, Zheng Shixiong, the vice president of Samsung SDI Co., Ltd., publicly stated that the energy density of Samsung SDI power batteries is currently 250Wh/kg, and is expected to reach the target of 350Wh/kg in 2023. Perhaps in 2017, Samsung has indeed achieved mass production of 250Wh/kg square shell batteries, but it is estimated that NCA ternary cathode materials may be used.

There are many types of square shell batteries. According to customer requirements, battery companies can tailor-made in terms of capacity, shape and size. Taking into account the difference in the formulation of the positive and negative materials, the energy density between the square shell cells of the same specification is more comparable. The gap between leading domestic and foreign square-shell power battery companies in terms of cell energy density may be very small. Perhaps from this technical condition alone, China may not be too far behind.

▌Cylindrical: Can Piccolo surpass Panasonic?

As one of the few domestic companies that focus on cylindrical power batteries, BAK told the first electric network that the energy density of its 2.75Ah power battery cells (18650) has reached 240Wh/Kg and plans to achieve 300Wh/ in 2020. kg.

How to evaluate the technical level of domestic power battery cells?

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

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

According to the information released by Tesla in 2017, the energy density of Panasonic's mass-produced NCA 18650 cylindrical power battery is about 250Wh/kg, and the energy density of 21700 monomers has reached 300Wh/kg. If BAK can mass produce 21700 cylindrical batteries in 2018, its energy density can surpass the level of Panasonic in 2017, nearly 8% higher.

is this real? In 2018, Panasonic has not publicly announced the latest commercialization technology progress. If BAK can achieve mass production of 324 Wh/kg cylindrical cells in 2018, then this may become the world's highest energy density mass production. Power battery.

▌Soft package: maybe more scientific research significance

The soft case, compared to the hard case (square case, cylinder), is a common packaging method for batteries, so it is commensurate with the side of the cylinder and the square.

How to evaluate the technical level of domestic power battery cells?

Tianneng’s mass-produced soft-pack batteries have reached an energy density of 230Wh/kg/kg, and will launch 250-260Wh/kg products by the end of 2018. At present, Tianneng’s soft pack power battery capacity is 2.5GWh to 3GWh, and it will be expanded to about 8GWh in 2019. All new capacity will be ternary soft pack routes.

The energy density of the batteries currently supplied by Carnegie New Energy is 220Wh/kg, and the products in 2018 will reach 250Wh/kg. As of the end of 2017, Carnegie's total production capacity was 2GWh, and will be expanded to 6GWh by the end of 2018.

Guoxuan Hi-Tech also disclosed in the record of investor relations activities that the company is progressing smoothly before undertaking the 300Wh/kg high energy density major technology project of the Ministry of Science and Technology. It has developed a three-yuan 811 soft-pack battery cell with an energy density of 302Wh/kg. The construction of pilot lines for related products has begun, and it is planned to start construction of production lines in 2019.

Tian Shuo, general manager of Beijing Keyi Power Technology Co., Ltd., analyzed that the enterprise undertaking the research of the major special power battery cell project of the Ministry of Science and Technology chose the three yuan soft package for its own reasons. "To complete a 300Wh/kg battery cell, it must be easier to pack it than a square case."

The mechanical strength of soft-pack batteries is poor, and the matching requirements of team technology and thermal management are relatively high, which poses certain challenges to the BMS design of vehicle companies. Moreover, some core components have not yet been made in China, but as the industry chain matures, the prospect of large-scale localization must be expected.

▌It's easier to put satellites than to do practical things

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

In today's power battery industry, news such as capital injections, corporate mergers and acquisitions are emerging one after another, and various battery concepts and laboratory breakthroughs continue one after another. News such as "Charge 800km for 1 minute" frequently refreshes the screen. Regardless of commercialization, it is a rogue to talk about technology. Each technical route has its own advantages and disadvantages. In the end, it is the enterprise's own ability, market selection, and product talk.