Internal Structure of SGMW Wuling Hongguang Mini EV Battery Pack

SGMW Wuling Hongguang Mini EV has two versions according to the difference in cruising range, one is 120km and the other is 170km, and the corresponding battery pack power is 9.2 (or 9.3) kWh and 13.8 (or 13.9) kWh respectively.

SGMW Wuling Hongguang Mini EV batteries are mainly supplied by six battery manufacturers: CATL, CALB, Gotion High-Tech, PHYLION, Great Power, Ruipu Energy.

Among them, the parameters of battery cells and battery packs provided by Gotion High-Tech, CATL and PHYLION are as follows:

The appearance of the SGMW Wuling Hongguang Mini EV Battery Pack.

Open the upper part of housing of the battery pack to see the overall internal layout. It looks very messy, probably before 2015, many battery pack solutions are like this. The structural design of this battery pack is rather peculiar. Its cells are arranged in the middle of the lower part of housing, surrounded by high-voltage connecting wires and high-voltage components.

There are 104 cells in the battery cell area, a total of 4 rows of cells, each with 26 cells, 2 4P13S battery modules, and the battery pack is 4P26S.

The 104 cells are directly laid on the bottom of the battery pack housing, which is a CTP technical idea. This is a highlight of the battery pack. It is also the application of this technology that makes up for the disadvantage of low mass energy density of the cells. The fixation in the horizontal direction is realized by the cell baffle and the structural beam at the other end, and the fixation in the Z direction is mainly realized by 5 battens. Both the baffle and the bead are fastened by bolts.

There is no glue or foam between the cells, and the cells are directly stacked in sequence, and foam is arranged between the outermost cell and the baffle. A plastic insulating board is arranged at the bottom of the battery pack housing, as shown below.

The design of this "city within a city" should be based on the battery pack housing conditions given by SAIC GM, with low volume utilization and low mass energy density, which basically offset the advantages brought by CTP technology.

However, the entire cell area can basically be regarded as suspended in the battery pack, because there are two layers at the bottom of the battery pack housing, and the insulating plates are arranged on the two-layer structure. It is very beneficial for mechanical safety protection. If you do a puncture test, you will not be able to puncture the battery cells from the outside of the battery pack housing in other directions except the bottom. Relatively weak mechanical safety is the ability of the Z-direction to deal with vibration and shock.

It has to be said that the electrical safety considerations of the entire battery pack are relatively rough, and the entire pack is full of exposed charged objects and messy high and low voltage wiring harnesses. According to the previous accident statistics of this type of scheme, these connections are the high-frequency points of the problem, and the more the later, the more prominent the reliability problem. In addition, the assembly and welding of these connections are basically manual, and the consistency of battery pack quality cannot be guaranteed.

Perhaps the 96V voltage level makes them less concerned about the overall electrical safety protection than 350V level EV.

From the perspective of integration efficiency and production cost, why doesn't this solution directly sample a solution with 4 battery modules? With such a high sales volume of SGMW Wuling Hongguang Mini EV, the scale effect of the battery module is not necessarily higher in cost than this solution, and the layout of the entire battery pack can be more concise.

A simple comparison of other Battery PACK integration schemes, except CATL adopts module technology, the other is basically the idea of CTP. In terms of electrical connection, wiring harness solutions are basically used, which is a technology that has been abandoned in mainstream high-speed EV solutions.

Under the pressure of the extreme cost budget of SGMW Wuling Hongguang Mini EV, designers have to re-examine what is suitable for their products, jump out of the framework of following mainstream design, and find solutions that can achieve cost budgets.

The design of this version of the battery pack is too rough, and its safety and reliability have yet to be tested by the market. Helplessly, this may be the difference between the Tesla Model 3 priced at about 300,000 CNY and the SGMW Wuling Hongguang Mini EV priced at about 30,000 CNY.

The popularity of SGMW Wuling Hongguang Mini EV has given us a lot of touches and is worth thinking about. On this scale, module technology will be a good direction, especially when there is already a mature module production line, the module technology can be replaced and maintainability is better. Large module technology and CTP technology bring more assembly problems.

Will CTC be a better direction? Based on the explosive SGMW Wuling Hongguang Mini EV, can the development of an electric chassis reduce the overall cost by more than ten percent, while at the same time it can derive more convertible models, that is, increase the customization and modification of the EV electric chassis.

Monthly sales of 20,000 battery packs, the battery cells cost is 0.6CZY/Wh*, and the entire battery pack is 0.8CZY/Wh*. Can you produce it, or do you want to produce it? To do or not to do it is a question. This may be the thinking that SGMW Wuling Hongguang Mini EV brings to the entire battery industry.

*Note: The above-mentioned battery cell and battery pack cost values are estimated values and are for reference only.

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*Related articles: Introduction of Wuling Hongguang MINI EV and its battery pack