Power battery thermal management device based on compounding of double-layer phase change material and liquid cooling plate

Abstract

The utility model discloses a power battery thermal management device based on compounding of a double-layer phase change material and a liquid cooling plate, which comprises a battery box body (1), batteries (2), the liquid cooling plate (3), a micro-channel (4), a first layer of phase change material (5) and a second layer of phase change material (6), and the batteries (3) are sequentially arranged in the middle of the battery box body (1) along the thickness direction. The first layer of phase change material (5) and the second layer of phase change material (6) are filled between the battery (2) and the liquid cooling plate (3), and the heat conductivity coefficient of the second layer of phase change material (6) close to the battery is smaller than that of the first layer of phase change material (5) close to the liquid cooling plate. Through the two layers of phase-change materials with different heat conductivity coefficients, the low-heat-conductivity-coefficient phase-change material absorbs heat through phase-change latent heat to serve as a heat transfer buffer area to improve the temperature uniformity of the battery pack, the high-heat-conductivity-coefficient phase-change material strengthens heat transfer to reduce the highest temperature of the battery pack, and the heat management efficiency and stability of the battery are improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the battery heat management technology field in energy storage system especially relates to a kind of power battery heat management device based on double-layer phase change material and liquid cooling plate composite. BACKGROUND

[0002] The rapid expansion of new energy vehicle industry makes the performance and safety problem of power battery, as its heart, become the focus. In the process of charging and discharging, the battery will release a large amount of heat energy, which will damage the battery performance and reduce the service life if not effectively managed, and even may cause safety accidents. Therefore, battery heat management technology becomes the key of industry research. At present, heat management technology mainly has air cooling, liquid cooling, thermoelectric cooling, heat pipe technology and a variety of methods using phase change material. Especially liquid cooling, because of its outstanding cooling effect, has been widely used in the market. Liquid cooling cools the battery by circulating liquid to absorb and discharge heat, but there are problems such as uneven cooling and high energy consumption. Phase change material heat management uses the characteristics of materials absorbing or releasing a large amount of heat when phase changing, which helps to stabilize the battery temperature and reduce the influence of temperature fluctuation, but it has poor thermal conductivity and volume expansion when absorbing heat. In order to combine the advantages of the two, researchers began to study the composite heat management technology of liquid cooling and phase change material. Although this technology has potential, the current research is shallow, and faces many challenges, such as composite material preparation, system structure design, cooling strategy, etc.

[0003] Liquid cooling and phase change material cooling each has advantages required for battery thermal management, but also has limitations. Combining the two is a promising research direction. In existing composite thermal management systems, phase change materials are usually filled in the gaps between batteries, and liquid cooling is directly in contact with the side of the battery. This system can improve temperature uniformity and reduce the maximum temperature, but the cooling liquid temperature still rises quickly, making it difficult to achieve ideal temperature uniformity, and the limited contact area between liquid cooling and phase change materials can cause the phase change material to quickly rise in liquid phase rate. For example, Chinese Patent No. CN220189776U discloses a two-stage phase change material and liquid coupled battery temperature control device, which includes square batteries and two-stage phase change material plates, a liquid cooling plate, and a fin that surrounds the battery pack and is placed across the battery pack; the two-stage phase change material plate is divided into two layers, each filled with a metal phase change material and an organic phase change material; but in this structure, the role of the two-stage phase change material plate is not obvious, and it does not explain what advantages the two-stage phase change material has compared to using an organic phase change material alone or a metal phase change material alone. In this structure, the battery is in contact with both the liquid cooling plate and the phase change material plate, and the two cooling methods cool the battery at the same time. A temperature control device using a single phase change material with good thermal conductivity may have better heat dissipation performance, and gallium is corrosive to metals and can form alloys with many metals at low temperatures. In addition, a two-stage phase change material plate is needed between every two batteries, and if there are enough batteries, the structure is too complex.

[0004] Therefore, how to reduce the maximum temperature of the battery module while maintaining the temperature uniformity of the battery module is a research hotspot in the field. Practical new type content

[0005] The purpose of the present utility model is to provide a power battery thermal management device based on a double-layer phase change material and a liquid cooling plate composite, which can effectively improve the efficiency and stability of battery thermal management, reduce the maximum temperature of the battery module, and maintain the temperature uniformity of the battery module.

[0006] To achieve the above purpose, the present utility model provides the following technical scheme:

[0007] A power battery thermal management device based on a double-layer phase change material and a liquid cooling plate composite, the device comprising a battery box, a battery, a liquid cooling plate, a microchannel, a first layer of phase change material, and a second layer of phase change material, the battery being arranged in the middle of the battery box along the thickness direction, the first layer of phase change material and the second layer of phase change material being filled between the battery and the liquid cooling plate, the thermal conductivity of the second layer of phase change material near the battery being less than that of the first layer of phase change material near the liquid cooling plate.

[0008] The utility model discloses a two-layer phase change material layer with different thermal conductivities is arranged: the first layer phase change material close to the liquid cooling plate has high thermal conductivity, can improve the temperature heat transfer efficiency, thereby strengthens the heat transfer and reduces the highest temperature of battery pack, and the second layer phase change material close to the battery has low thermal conductivity and is used as the buffer area of heat conduction, mainly relies on the latent heat of phase change and absorbs heat, is used as the heat transfer buffer area, improves the temperature uniformity of battery pack, thereby is favorable for improving the efficiency and stability of battery thermal management.

[0009] As preferred, the first layer phase change material comprises a single phase change material, and the second layer phase change material is a composite phase change material comprising a single phase change material and a thermal conductive material, and the single phase change materials in the first layer phase change material and the second layer phase change material are the same.

[0010] As preferred, the material of the single phase change material is selected from paraffin or calcium chloride hexahydrate. In the utility model, the first layer phase change material close to the battery is a single conventional phase change material with low thermal conductivity, such as paraffin (thermal conductivity is generally 0.1-0.5 W / (m K)) and calcium chloride hexahydrate (thermal conductivity is generally 0.8-1.2 W / (m K)). And the second layer phase change material close to the liquid cooling plate is a composite phase change material with high thermal conductivity, such as paraffin and calcium chloride hexahydrate added with expanded graphite or hexagonal boron nitride (thermal conductivity varies according to the content of expanded graphite, generally greater than 3 W / (m K)).

[0011] As preferred, the organic phase change materials are located in the hollowed-out aluminum plate to solve the leakage problem and the mutual mixing problem of the two different phase change materials caused by the volume expansion of the melted phase change materials.

[0012] The thickness of the second layer phase change material is less than the thickness of the first layer phase change material. As preferred, the thickness of the second layer phase change material is 1 / 7-1 / 2 of the thickness of the first layer phase change material.

[0013] As preferred, the thickness of the first layer phase change material is 4-7 mm, and the thickness of the second layer phase change material is 1-3 mm.

[0014] It can be understood that the first layer phase change material and the second layer phase change material are separated by the aluminum baffle in the battery box body, so that they are in their respective areas and do not directly contact, preventing the leakage and mutual mixing of the melted phase change materials.

[0015] As preferred, the material of the liquid cooling plate and the battery box baffle is aluminum.

[0016] As preferred, micro-channels are arranged in the liquid cooling plate, and the micro-channels are connected to the cooling liquid inlet main pipeline and the cooling liquid outlet main pipeline through the battery box respectively, and the flow direction of the cooling liquid in the micro-channels is from top to bottom.

[0017] As preferred, the shape of the flow channel is Z-shaped, U-shaped or J-shaped.

[0018] Further, the battery box is perforated at the position corresponding to the inlet and outlet of the liquid cooling plate flow channel, so that the liquid cooling plate can be connected to the cooling liquid inlet main pipeline and the cooling liquid outlet main pipeline through the wall surface of the battery box.

[0019] As preferred, the battery is a square battery, and the two layers of phase change materials are located on the side with a larger thermal conductivity.

[0020] The geometric size of the liquid cooling plate channel and the geometric size of the phase change material layer of the battery thermal management device can be adjusted according to different working scenes.

[0021] Specifically, the battery thermal management device based on the double-layer phase change material and the liquid cooling plate composite provided by the utility model comprises two liquid cooling plates in direct contact with a high-thermal-conductivity layer, a plurality of batteries are closely arranged in a thickness direction, phase change materials are filled between the batteries and the liquid cooling plates, the internal structure of the square battery is mainly a stack of current collectors-electrodes-separators-electrodes-current collectors along the thickness direction of the battery, and therefore the thermal conductivity of the battery along the thickness direction is small, and the battery, the phase change material and the liquid cooling plate are arranged accordingly.

[0022] Compared with the liquid cooling plate using a single conventional phase change material, the battery thermal management device has higher heat transfer efficiency, and the heat of the latter may be accumulated in the thin layer of phase change material close to the battery and cannot be transferred out, so that the highest temperature of the battery cannot be effectively controlled.

[0023] Compared with the prior art, the utility model has the following advantages:

[0024] This invention provides a power battery thermal management device based on a composite of dual-layer phase change material and a liquid cooling plate. It overcomes the disadvantage of traditional phase change materials having excessively low thermal conductivity by combining a liquid cooling plate with two layers of phase change material with different thermal conductivity. By bringing the high-thermal-conductivity phase change material (the first layer) into contact with the liquid cooling plate, the heat transfer efficiency between the phase change material and the liquid cooling plate in that area is improved. In the thinner layer of low-thermal-conductivity phase change material near the battery pack (the second layer), heat conduction is slower, and most of the heat is absorbed as latent heat of the phase change material, preventing rapid heat transfer to the coolant and avoiding a rapid increase in the temperature difference between the coolant inlet and outlet. This improves the temperature uniformity of the battery module to some extent. Furthermore, the coolant flow rate can be adjusted according to different battery operating conditions to more effectively dissipate heat from the battery module. Therefore, the device provided by this invention can effectively improve the efficiency and stability of battery thermal management. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of a power battery thermal management device based on a composite of a double-layer phase change material and a liquid cooling plate provided by this utility model.

[0026] Figure 2 This is a top view of a power battery thermal management device based on a composite of a double-layer phase change material and a liquid cooling plate provided by this utility model;

[0027] Figure 3 This is an exploded view of the overall structure of a power battery thermal management device based on a composite of a double-layer phase change material and a liquid cooling plate, provided by this utility model.

[0028] Figure 4 This is a schematic diagram of the battery module in the power battery thermal management device that combines a double-layer phase change material and a liquid cooling plate, as well as the maximum temperature after 3C discharge using a single phase change material, provided in Example 1.

[0029] Figure 5 This is a schematic diagram of the battery module in the power battery thermal management device that combines a double-layer phase change material and a liquid cooling plate, as well as the maximum temperature difference after 3C discharge using a single phase change material, provided in Example 1.

[0030] Figure 6 This is a schematic diagram of the battery module in the power battery thermal management device that combines a double-layer phase change material and a liquid cooling plate, as well as the liquid fraction of the phase change material after 3C discharge using a single phase change material, provided in Example 1.

[0031] The components are: 1. Battery housing, 2. Battery, 3. Liquid cooling plate, 4. Microchannel, 5. First layer of phase change material, and 6. Second layer of phase change material. Detailed Implementation

[0032] To make the purposes, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0033] As shown in Figures 1-3 The utility model provides a kind of power battery thermal management device based on double-layer phase change material and liquid cooling plate composite, comprising:

[0034] Battery 2, battery 2 is sequentially arranged in thickness direction and is placed between second layer phase change material 6;

[0035] First layer phase change material 5, second layer phase change material 5 is between liquid cooling plate 3 and second layer phase change material 6.

[0036] Second layer phase change material 6, second layer phase change material 6 is covered battery 2 on both sides of battery 2;

[0037] Liquid cooling plate 3, liquid cooling plate 3 is directly contacted with first layer phase change material 5, for improving heat transfer efficiency and ensuring that phase change material does not melt completely;

[0038] Cooling liquid inlet and cooling liquid outlet of microchannel 4 of liquid cooling plate 3 extend outward and connect with cooling liquid main road;

[0039] Battery box 1, battery 2, first layer phase change material 5, second layer phase change material 6 and liquid cooling plate 3 are wrapped inside, and aluminum baffle in battery box 1 separates first layer phase change material 5 and second layer phase change material 6.

[0040] Specifically, as a kind of implementation mode, the utility model provides a kind of power battery thermal management device based on double-layer phase change material and liquid cooling plate composite, comprising:

[0041] Battery box 1, battery 2, liquid cooling plate 3, microchannel 4, first layer phase change material 5 and second layer phase change material 6. Battery 2 is sequentially arranged in thickness direction and is placed in intermediate position, liquid cooling plate 3 is arranged on both sides of battery 2 and has gap, first layer phase change material 5 and second layer phase change material 6 are filled between battery 2 and liquid cooling plate 3, microchannel 4 of liquid cooling plate 3 extends outward and connects with cooling liquid inlet main pipe and cooling liquid outlet main pipe at the position of cooling liquid inlet and cooling liquid outlet through the wall surface of battery box 1, cooling liquid passes through Z-shaped microchannel 4 from cooling liquid inlet main pipe and reaches cooling liquid outlet main pipe.

[0042] The liquid cooling plate 3 is made of aluminum material with two layers of hollow plates filled with phase change materials, and the battery box 1 is made of aluminum or stainless steel material. The part of the liquid cooling plate 3 penetrating the battery box 1 is sealed by welding.

[0043] The cooling liquid flows from top to bottom in the micro-channel 4. The height of the battery box 1 is greater than the height of the battery 2.

[0044] Example 1

[0045] As shown in FIG. 1, the battery 2, the liquid cooling plate 3, the first layer of phase change material 5 and the second layer of phase change material 6 are symmetrically arranged. Figure 3 The battery box in this embodiment is made of aluminum material to reduce weight. The thickness of the battery box 1 is 2 mm, the thickness of the baffle separating the two layers of phase change materials in the box is 0.5 mm, the thickness of the liquid cooling plate 3 is 4 mm, the thickness of the first layer of phase change material 5 is 5 mm, and the thickness of the second layer of phase change material 6 is 1 mm. The first layer of phase change material 5 is calcium chloride hexahydrate with a melting temperature of 30℃, and the second layer of phase change material 6 is a composite phase change material formed by expanded graphite and calcium chloride hexahydrate.

[0046]

[0047] FIG. 6 is a schematic diagram of the maximum temperature of the battery module after 3C discharge in the power battery thermal management device based on the double-layer phase change material and the liquid cooling plate composite provided in this embodiment. In the abscissa, group 1 is a single phase change material calcium chloride hexahydrate with low thermal conductivity, and group 2 is a single composite phase change material (formed by calcium chloride hexahydrate and expanded graphite) with high thermal conductivity. As can be seen from FIG. 6, the maximum temperature of the battery in the device provided in this embodiment is lower than that of group 1, and although it is higher than that of group 2, it is still within the ideal working temperature range. Figure 4 Figure 4 FIG. 7 is a schematic diagram of the maximum temperature difference of the battery module after 3C discharge in the power battery thermal management device based on the double-layer phase change material and the liquid cooling plate composite provided in this embodiment. As can be seen from FIG. 7, the temperature difference of the battery module using the high-thermal-conductivity single-layer phase change material of group 2 has exceeded the ideal working temperature difference (5℃).

[0048] Figure 5 Figure 5 FIG. 8 is a schematic diagram of the liquid fraction of the phase change material after 3C discharge in the power battery thermal management device based on the double-layer phase change material and the liquid cooling plate composite provided in this embodiment. The liquid fraction in the device provided in this embodiment is between the two groups.

[0049] Figure 6 Example 2-3

[0050] Example 2-3 ​​

[0051] The power battery thermal management device based on the double-layer phase change material and liquid cooling plate composite provided in Embodiments 2-3 can refer to Embodiment 1, and the difference is that the thickness of the first layer phase change material 5 is 4 mm and 6 mm respectively.

[0052] Embodiments 4-5

[0053] The power battery thermal management device based on the double-layer phase change material and liquid cooling plate composite provided in Embodiments 4-5 can refer to Embodiment 1, and the difference is that the thickness of the second layer phase change material 6 is 1.5 mm and 2 mm respectively.

[0054] Embodiment 6

[0055] The power battery thermal management device based on the double-layer phase change material and liquid cooling plate composite provided in this embodiment can refer to Embodiment 1, and the difference is that the first layer phase change material 5 is paraffin with a melting point of 35℃, and the second layer phase change material 6 is a phase change material composed of expanded graphite and paraffin.

[0056] In summary, the power battery thermal management device provided by the utility model has simple structure, the heat generated by the battery is first absorbed by the second layer phase change material 6 in the form of latent heat, the heat conduction in this area is slow, and the temperature difference of the liquid inlet and outlet in the liquid cooling plate 3 can be reduced to improve the temperature uniformity of the battery pack, in the first layer phase change material 5 area, the phase change material in this area is composed of high thermal conductivity material and traditional phase change material, and has good thermal conductivity, the heat transfer efficiency between the liquid cooling plate 3 and the phase change material is strengthened, and the heat in the phase change material is taken away by the liquid cooling, so that the phase change material is not easy to melt completely. The whole heat dissipation device effectively improves the heat dissipation efficiency of the battery and prolongs the service life of the battery.

[0057] Although the above-mentioned embodiments are disclosed in the present application, the above-mentioned content is only for the convenience of understanding and adopting the embodiments, and any person skilled in the art should understand that any modification and change can be made in the form and details of the implementation without departing from the spirit and scope of the utility model disclosed in the present application, and the patent protection scope of the utility model should be determined by the scope defined by the attached claims.

Claims

1. A power battery thermal management device based on a double-layer phase change material and a liquid cooling plate composite, characterized in that, The device comprises a battery box (1), a battery (2), a liquid cooling plate (3), a microchannel (4), a first layer of phase change material (5), and a second layer of phase change material (6). The battery (2) is arranged in the middle of the battery box (1) in the thickness direction. The first layer of phase change material (5) and the second layer of phase change material (6) are filled between the battery (2) and the liquid cooling plate (3). The thermal conductivity of the second layer of phase change material (6) near the battery is smaller than that of the first layer of phase change material (5) near the liquid cooling plate.

2. The power battery thermal management device based on double-layer phase change material and liquid cooling plate composite according to claim 1, characterized in that, The first layer of phase change material (5) comprises a single phase change material, and the second layer of phase change material (6) is a composite phase change material comprising a single phase change material and a thermal conductive material. The single phase change material in the first layer of phase change material (5) and the second layer of phase change material (6) is the same.

3. The power battery thermal management device based on double-layer phase change material and liquid cooling plate composite according to claim 2, characterized in that, The material of the liquid cooling plate (3) is aluminum. The material of the single phase change material is selected from paraffin or calcium chloride hexahydrate. The material of the thermal conductive material is selected from expanded graphite or hexagonal boron nitride.

4. The power battery thermal management device based on double-layer phase change material and liquid cold plate composite according to claim 1, characterized in that, The thickness of the second layer of phase change material (6) is smaller than that of the first layer of phase change material (5).

5. The power battery thermal management device based on double-layer phase change material and liquid cold plate composite according to claim 4, characterized in that, The thickness of the first layer of phase change material (5) is 4-7 mm. The thickness of the second layer of phase change material (6) is 1-3 mm.

6. The power battery thermal management device based on double-layer phase change material and liquid cold plate composite according to claim 1, characterized in that, The microchannel (4) is arranged in the liquid cooling plate (3). The flow direction of the cooling liquid in the microchannel (4) is upward in and downward out.

7. The power battery thermal management device based on double-layer phase change material and liquid cold plate composite according to claim 6, characterized in that, The shape of the microchannel (4) is Z-shaped, U-shaped, or J-shaped. 8.The power battery thermal management device based on double-layer phase change material and liquid cooling plate composite of claim 6, wherein, The inlet and outlet positions of the microchannel (4) are consistent with the vacant positions of the battery box (1). 9.The power battery thermal management device based on double-layer phase change material and liquid cooling plate composite of claim 1, wherein, The battery (2) is a square battery. The first layer of phase change material (5) and the second layer of phase change material (6) are located on the side with larger thermal conductivity of the battery (2).

10. The power battery thermal management device based on double-layer phase change material and liquid cold plate composite according to claim 1, characterized in that, The height of the battery box (1) is greater than the height of the first layer of phase change material (5), the second layer of phase change material (6), and the battery (2).

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