CATL's 587Ah energy storage-specific battery cells officially enter mass production | The Latest Frontline

On June 10th, CATL announced at the "2025 Energy Storage 587 Technology Day" that its 587Ah energy storage-specific battery cells have officially started mass production and delivery, and are currently being produced at the CATL Jining Base.

In 2018, CATL began to layout its energy storage battery business. By the end of last year, CATL's global market share of energy storage batteries was 36.5%, and its energy storage battery shipments ranked first in the world.

As of now, CATL's main energy storage products include the Tianheng Energy Storage System, which was upgraded to TENER Stack this year. The single-unit energy storage capacity has increased from 6.25MWh to 9MWh. There are also three generations of large-capacity energy storage battery cells, namely 280Ah, 314Ah, and 587Ah.

Among them, the 587Ah battery cell is a product that CATL began to layout three years ago and is about to be officially mass-produced and delivered.

Compared with CATL's previous generation of products, the single-cell energy density of the 587Ah battery cell has increased by 10% to 434Wh/L, and the system energy density has increased by 25%.

CATL achieved these parameter improvements not by simply enlarging the battery cell size, but by achieving greater energy density through methods such as close-packing design, high-density coating, and construction of fast ion channels in the cathode material.

In addition, by reducing ohmic polarization, reaction polarization, and concentration polarization, CATL has achieved an initial energy conversion efficiency of 96.5% for the battery cells. Through its self-developed impedance growth suppression technology, it delays the thickening of the SEI and suppresses the generation of high-impedance products, reducing the attenuation of the battery cell's energy conversion efficiency during actual application.

Like the previous two generations of products, when designing the 587Ah battery cell, CATL considered not only from the perspective of battery technology itself but also from the system dimension. Therefore, the third-generation energy storage battery cell is still a product based on the container size standard.

Currently, the capacities of domestic energy storage power stations are basically configured as integers such as 200MWh and 400MWh. According to the latest power station design standards, each partition of an energy storage power station cannot exceed 50MWh, and eight 6.25MWh systems exactly form a partition.

In addition, there are also certain standards for the transportation specifications of energy storage systems. Energy storage containers must be transported by container skeleton trucks, and the total weight cannot exceed 60 tons. After subtracting the vehicle's own weight of 15 tons, 45 tons is the maximum weight value for compliant transportation in China.

The Tianheng Energy Storage System integrated with CATL's 587Ah battery cells has a power of 6.25MWh, and its weight is controlled within 45 tons, which exactly meets the requirements of national standard partitions and transportation regulations.

For CATL, with the launch of this battery cell, the integration efficiency of its energy storage systems has also been improved, and the product cost will subsequently decrease. The 587Ah battery cell combined with CATL's four-column architecture design can reduce the number of battery modules in the entire system by 33%, system components by 40%, and system integration cost by 15%.

For the entire industry, there has always been the problem of inflated lifespan parameters in the energy storage industry.

According to statistics from domestic authoritative institutions cited by CATL, in the energy storage projects put into operation in the early stage, the products claimed a cycle life of 10,000 or 15,000 times, but the actual operation was only 3 to 5 years, and the annual cycle times were mostly less than half of the designed value.

In addition, there have been frequent safety accidents in the entire power station caused by a single battery cell in the industry. Although many industry insiders have tried to compensate for the intrinsic defects of battery cells through software and power electronic equipment, CATL said that this method is difficult to address the root cause because the system performance is determined by the short board, that is, the intrinsic characteristics of the battery cells.

Regarding the above problems, CATL believes that the practice of simply enlarging the battery cell size to increase the battery cell capacity has magnified these problems.

CATL analyzed the principles behind the above two major problems from the perspective of electrochemical characteristics:

After the width of the battery cell increases, the internal resistance will increase, resulting in a decrease in charging and discharging efficiency. The distribution of the internal current in the battery cell will also be uneven, resulting in a greater difference in the degree of lithium-ion deintercalation in different regions, accelerating the local aging of the battery cell. More importantly, after the battery cell becomes wider, once thermal runaway occurs, the too long exhaust path will cause the high-temperature gas to fail to be discharged in a timely and smooth manner, increasing the risk of battery cell explosion.

Increasing the height of the battery cell also brings two problems:

Firstly, in the middle and later stages of the battery cell's lifespan, due to the consumption of the electrolyte and the excessive height, the electrolyte's climbing ability is insufficient, making it difficult to fully infiltrate the entire electrode material, especially the top area. As a result, the phenomenon of "lifespan cliff" of the battery cell is likely to occur.

Secondly, heat is generated during the charging and discharging process of the battery cell. If the height is too high, the temperature difference between the top and bottom of the battery cell will increase. The continuous and excessive temperature difference will also accelerate the attenuation of the battery cell's lifespan.

Therefore, CATL did not blindly enlarge the battery cell or simply pursue an excessively high battery cell capacity. Instead, it defined the battery cell with a capacity of 587Ah and a relatively reasonable size. On the premise of increasing the capacity, it increased the reliable charging and discharging times of the battery cell throughout its life cycle by 20%.

CATL's 587Ah battery cell strives to achieve a balance between safety and performance. Its efforts will undoubtedly promote the industry to more rationally handle the balance relationship among factors such as the safety, lifespan, and capacity of energy storage battery cells. It is expected that in the near future, energy storage batteries with higher capacity and a balance between safety and lifespan will emerge.