Passenger Car Battery Becomes Large And Thick

- Oct 24, 2019-

Subsidies have fallen sharply, and power battery reduction is imminent. In addition to the innovative material system, making thick and large battery specifications has become the most direct way to reduce power quality for power battery companies.

According to channel news, power battery companies are subverting traditional process routes, and the square cell size is the new energy passenger car battery pack level, which simplifies structural design, increases energy density, extends battery life and reduces costs. The product is already in the verification phase.

There are also power battery companies based on the scene development of the cell technology platform, in the VDA-based size standard, the thickness of the cell is 1.5 times, 2 times the trend is increasing.

Previously, the industry has discussed more about the power cylinders, mainly focusing on the advantages and trends of the evolution from 18650 to 21700, 26650, etc. In fact, the evolution trend of square batteries is also the same.

According to the data of the High-tech Research Institute of Lithium-Ion Research Institute (GGII), in the TOP10 of the H1 power battery cell core capacity of 2019, the square single cell size of 79mm (thickness) x148 mm (width) x97 mm (height) is The 7.77GWh installed capacity ranked first, and the supporting models were mainly passenger cars.

Although the H1 power battery installed capacity involves up to 204 types of single cell, in the passenger car square cell specifications, 79mm is the thickest cell size at present. Other square batteries are mostly concentrated in 54148, 26148 and other specifications.

The data shows that 79148 square battery suppliers are concentrated in the Ningde era and the era of SAIC, supporting car companies including Beiqi, Geely, SAIC, GAC, Weimar, Changan, Dongfeng, FAW, Beiqi New Energy, Chery and so on. From the perspective of terminal application verification and acceptance, square thick batteries have won the favor of the market.

The core requirements for making thick and large cell cores are: 1. It can increase the energy density; 2. The larger the thickness, the higher the capacity, which means the lower the cost per Wh; 3. The larger the cell, the more the structural component is used. Reduce, the difficulty of grouping is reduced, and the overall cost is lower.

High-tech lithium battery has learned that it is the most mainstream method for square power battery enterprises by increasing the size of the battery core by parallel processing the core volume to achieve the effect of increasing the capacity of the battery core. However, due to the difference in technical strength, not all battery companies can easily achieve the thickness of the battery.

A technical chief of the power battery company said that the thickness of the battery core is 79mm. It is still technically difficult for ordinary battery companies. For example, the process and heat dissipation design will bring great challenges and difficulties. At the same time, the increase in the degree of extrusion of the pole piece caused by the thickness of the battery core also increases the safety risk of the battery.

In addition, in the actual application process, there are two possible problems:

One is the problem of battery bulging. Because the lithium battery has a certain pressure inside the battery during charging and discharging, and under the same pressure, the larger the force area, the more serious the deformation of the battery wall. The expansion of the battery core will cause an increase in the internal resistance of the battery, partial depletion of the electrolyte, and even deformation of the welded portion of the casing, resulting in leakage of the electrolyte.

This tests whether the battery manufacturer can guarantee the uniformity of the current sharing characteristics of the internal core of the battery after parallel connection.

Second, the heat dissipation performance of the battery core is deteriorated. As the volume of the monomer increases, the distance between the heat-generating portion of the battery core and the housing becomes longer, and the conductive medium and interface become more numerous, resulting in difficulty in heat dissipation. At the same time, uneven distribution of heat between the monomer and the monomer may also result in poor heat dissipation performance.

Therefore, although the square battery has become "main" and "large" is the mainstream trend, occupying a large market share in passenger cars, but the thickest core technology is still concentrated in the hands of leading power battery companies.

On the one hand, on the one hand, the performance breakthrough and advantage gap in battery core technology will further increase the market gap between power battery companies; on the other hand, the choice of battery core specifications will also promote the terminal market size specification. The reduction has further reduced the cost of power batteries from the perspective of large-scale manufacturing.