Ūdens{0}}dzesēšanas plākšņu materiālu izstrāde un pielietošana jauniem enerģijas transportlīdzekļiem
Development and design of new energy water-cooled plate materials
1.1 Material design and application of brazing water-cooling plate
There are two main types of brazed water-cooling structures for commonly used batteries: water-cooled plate structure and direct-cooled plate structure, as shown in Figure 2. Usually aluminum brazing sheet products are brazed with two upper and lower O-state aluminum sheets, one of which is stamped with a flow channel structure to facilitate the flow of antifreeze to cool the battery, thereby continuously cooling the battery.
For the water-cooled plate materials of these two structural parts, the strength of the material and the corrosion resistance of the product are usually mainly considered. High-strength composite materials combined with water-cooled plate structure design can achieve the purpose of thinning and cost reduction, so the continuous development of new materials is also an important basis for the development of water-cooled plates.
2.Meet the development of new materials for water-cooled plates
2.1 Three different core material alloy designs
The main comparison is the composition design of the standard 3003 aluminum alloy and the three newly developed materials A, B and C three core materials. It can be seen from Table 2 that A and B are improved materials of 3003 aluminum alloy. Compared with 3003 aluminum alloy, they contain higher Cu and Mn elements; and C core material except for higher content of Cu and Mn elements In addition, it also contains a higher content of Si element.
2.2 Electric potential after brazing of different materials Figure 4 shows the influence of the main alloying elements on the electric potential of the aluminum alloy. As the content of Mn, Cu, etc. increase, the electrical potential of the alloy increases significantly; as the content of Zn increases, the electrical potential of the alloy decreases significantly, and then gradually stabilizes. The influence of Si and Mg on the alloy potential is relatively small.
3. Discussion
3.1 The influence of material structure design on corrosion
It can be seen from the material corrosion test results that common 3003 aluminum alloy is prone to pitting corrosion. If a sacrificial layer is added to the surface of the material, the corrosion mechanism of the material will change, that is, from pitting corrosion to layered corrosion (see Figure 6), which can greatly improve the corrosion resistance of the material.
3.2 Material potential difference design
The material is designed to achieve the difference between the surface potential and the core material potential, thereby generating Brown bands and improving the corrosion ability. By alloying and matching the composite structure of the composite material, the brazing layer and the core material layer will form a layer of 30-50 μm high-density precipitation zone, as shown in Figure 7. Its potential is about 50 mV lower than that of the core material, and laminar corrosion will occur preferentially along the high-density precipitation zone, thereby prolonging the life of the core material. This can also explain why the corrosion ability of A/B aluminum alloy composite material is better than that of C, and more obviously better than 3003 aluminum alloy. It is because A/B aluminum alloy composite material can produce the effect of Brown band through optimized composition design.
4. Conclusion
(1) The water-cooled plate is an important heat exchanger for battery cooling management necessary for new energy vehicles. It can be designed to improve strength and corrosion resistance through different alloy designs.
(2) The corrosion resistance can be improved by adding a sacrificial layer, or by designing a structure that produces different potential bands.
