Why choose soft pack lithium battery -Lithium - Ion Battery Equipment

Why choose soft pack lithium battery -Lithium - Ion Battery Equipment

On June 14th, the theme lecture "Unlocking the Safety Performance of Qiantu Automobile Battery" was held at Qiantuyi Beijing Sanlitun store. Regarding the safety of power lithium batteries that consumers are most concerned about, Mr. Zhai Sheng, a technical expert of Qiantu Automobile's three electric vehicles, shared on the spot. Qiantu Motor's complete technical development path for power lithium batteries and technical solutions for battery safety performance.

Mr. Zhai Sheng, General Manager of Walt Business Unit and Technical Expert of Qiantu Motor's Three Electrics

Why choose soft pack lithium battery

In fact, soft-pack lithium batteries are not completely new. The reason why cylindrical and square batteries have become mainstream at present is related to cost and R&D cycle. As early as 2010, Qiantu Motor established a technical route based on the standard box of soft-packed cells. Zhai Sheng mentioned: "As a vehicle developer, the safety and consistency of the battery are the core issues we first consider." It is for this reason that Qiantu Motor abandoned the cylindrical and square single-cell batteries used in the mainstream market at that time, and forward-lookingly adopted soft-pack lithium batteries with higher safety and obvious advantages in energy buffering and release.

Compared with cylindrical and square batteries with a fixed shape, due to the use of aluminum-plastic film packaging, the soft-pack lithium battery will have a slow-release process when the internal energy gathers and reaches the burst point, rather than a burst explosion phenomenon, which is simply a soft-pack lithium battery. The internal short circuit of the battery will not explode immediately, but will expand and release energy first, so that after the vehicle alarms, it will provide more sufficient response and escape time for the occupants. The higher safety advantage makes the soft-pack lithium battery the research and development basis for the entire power lithium battery technology path of Qiantu Motor.(Lithium - Ion Battery Equipment)

From the perspective of OEMs, soft-pack lithium batteries have gradually been favored by more first-tier manufacturers after development in recent years. GM, Nissan, Mercedes-Benz, and Audi all have some achievements in the development and adaptation of soft-pack power lithium batteries. invested. At present, the world's best-selling electric car, the Nissan Leaf, is also equipped with a soft-pack lithium battery. At the supplier level, suppliers such as CATL and LG, which are large-scale battery cell factories, are also increasingly participating in the R&D and manufacturing of soft-pack lithium batteries.

Innovative Standard Battery Box

A few days ago, a series of spontaneous combustion incidents of electric vehicles made the public more or less psychologically shadowed. Taking cylindrical cells as an example, since the important heat source of the battery is located in the tabs, and the cooling circuit laid under the battery pack is difficult to balance the temperature difference between the upper and lower sides of the battery, the cylindrical battery pack inherently has the disadvantage that it is difficult to do a good job of BMS thermal management. Coupled with the aging of the battery after years of use, the diaphragm of a battery is punctured under the influence of lithium dendrites, resulting in an internal short circuit, which is prone to thermal runaway similar to dominoes, causing a chain reaction of the battery pack. Now, in order to ensure the energy density of the battery pack, the arrangement between the cells is also very close, which once again increases the risk of thermal runaway. From this, we understand that in addition to the safety of single cells, the safety measures between batteries and batteries, that is, the overall battery pack, are also particularly important.

The standard battery box designed by Qiantu Motor

Faced with this problem, Qiantu Motor adopts a standard battery box design. Due to the small volume change of the battery cells during the charging and discharging process, we call it "breathing effect". Inside the Qiantu standard battery box, a buffer design is used between the cells to absorb the dimensional changes caused by the breathing effect of the battery cells. And form an internal buffer in the event of collisions, bumps, etc.

The exterior of the battery box adopts a high-strength composite material shell, which makes its crash performance test score 30% higher than the national standard and meets the requirements of IP67 protection level. It is worth mentioning that the airtight casing of the standard battery box can also efficiently cooperate with the battery thermal management system, thereby ensuring the consistency of the cell temperature.



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