Battery pack

Abstract

The utility model relates to a battery pack which comprises at least two groups of battery cell modules arranged along a first direction, each group of battery cell modules comprises a plurality of battery cells arranged along a second direction, and a flow channel for a single-phase cooling liquid to flow is arranged between adjacent battery cells along the second direction; a heat dissipation assembly is arranged between every two adjacent battery cell modules and comprises a baffle and a solid-liquid phase change heat dissipation medium, the baffle is connected with the bottom of the upper battery cell module in the two adjacent battery cell modules in an attached mode, and the space between the lower side of the baffle and the top of the lower battery cell module in the two adjacent battery cell modules is filled with the solid-liquid phase change heat dissipation medium; and the density of the solid-liquid phase change heat dissipation medium is smaller than that of the single-phase cooling liquid. According to the battery pack, the latent heat of the solid-liquid phase change heat dissipation medium from the solid state to the liquid state is utilized to absorb the heat at the top of the lower side battery cell module, so that the top of the lower side battery cell module can be cooled, the overall temperature uniformity of the battery cells is improved, and the temperature detected by the temperature sensor can accurately reflect the overall temperature of the battery cells.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to battery packs. Background Technology

[0002] With the rapid development of the energy storage industry and the upgrading of battery technology, the thermal management technology of energy storage batteries has gradually evolved from the early direct air cooling, air conditioning air cooling, cold plate liquid cooling, and immersion liquid cooling.

[0003] In existing technologies, liquid cooling solutions for battery packs often involve placing cold plates or channels between the sides of adjacent cells, allowing the coolant to flow through the cold plates or channels in a designed direction. This liquid cooling method can specifically dissipate heat and cool down areas on the cells where heat tends to accumulate.

[0004] To monitor the temperature at various locations within the battery pack, temperature sensors are often placed on the top of the battery cells. However, the presence of tabs, temperature sensors, and wiring harnesses on the top of the cells results in an irregular surface, making flow channel design difficult and preventing the cold plate from adhering properly. This makes it difficult to effectively dissipate heat from the top of the cells, turning it into the most unfavorable point for heat dissipation. Consequently, the overall temperature uniformity of the cells is poor, and the temperature detected by the temperature sensors cannot accurately reflect the overall temperature of the cells. Utility Model Content

[0005] Based on this, it is necessary to provide a battery pack that addresses the problem in the existing technology where the top of the battery cell is equipped with tabs, temperature sensors, and wiring harnesses, resulting in an irregular surface, difficulty in flow channel design, and inability to attach the cold plate. This makes it difficult to effectively dissipate heat from the top of the battery cell, making the top of the battery cell the most unfavorable point for heat dissipation. Consequently, the temperature uniformity of the battery cell as a whole is poor, and the temperature detected by the temperature sensor cannot accurately reflect the overall temperature of the battery cell.

[0006] A battery pack includes: at least two sets of cell modules arranged along a first direction, each set of cell modules including a plurality of cells arranged along a second direction, and a flow channel for single-phase coolant to flow between adjacent cells along the second direction; wherein the first direction is a vertical direction, and the second direction is perpendicular to the first direction.

[0007] A heat dissipation assembly is provided between two adjacent sets of battery cell modules. The heat dissipation assembly includes a baffle and a solid-liquid phase change heat dissipation medium. The baffle is attached to the bottom of the upper battery cell module in the two adjacent sets of battery cell modules. The solid-liquid phase change heat dissipation medium is filled between the lower side of the baffle and the top of the lower battery cell module in the two adjacent sets of battery cell modules. The density of the solid-liquid phase change heat dissipation medium is less than the density of the single-phase coolant.

[0008] In one embodiment, the baffle includes a partition and a surrounding plate. The partition is attached to the bottom of the upper battery cell module in two adjacent sets of battery cell modules. The solid-liquid phase change heat dissipation medium is filled between the lower side of the partition and the top of the lower battery cell module in two adjacent sets of battery cell modules. The surrounding plate is connected to the outer edge of the partition and protrudes downward from the partition to surround the periphery of the solid-liquid phase change heat dissipation medium.

[0009] In one embodiment, the lower end of the enclosure is at a lower height than the lower end of the solid-liquid phase change heat dissipation medium in the corresponding heat dissipation assembly.

[0010] In one embodiment, the height of the upper surface of the outer shell of the lower cell in one of two adjacent sets of cell modules is higher than or equal to the height of the lower end of the enclosure in the corresponding heat dissipation assembly.

[0011] In one embodiment, the projections of the upper and lower battery cell modules in two adjacent sets of battery cell modules toward the baffle along the first direction are completely located within the baffle.

[0012] In one embodiment, the baffle is a liquid-cooled plate with a channel inside for coolant to flow through.

[0013] In one embodiment, the heat dissipation assembly further includes a thermally conductive metal layer, which is attached to the lower surface of the baffle.

[0014] In one embodiment, the thermally conductive metal layer has a plurality of mesh holes; or, the thermally conductive metal layer is a porous metal structure.

[0015] In one embodiment, the top of the lower battery cell module in two adjacent sets of battery cell modules is spaced apart from the thermally conductive metal layer in the corresponding heat dissipation assembly.

[0016] In one embodiment, the solid-liquid phase change heat dissipation medium is paraffin wax.

[0017] The aforementioned battery pack operates at a low temperature when not in use, with the solid-liquid phase change heat dissipation medium in a solid state. During operation, as heat is generated in various parts of the battery pack, the solid-liquid phase change heat dissipation medium absorbs heat from the top of the lower cell module, transforming into a liquid state. This latent heat from solid to liquid phase absorbs heat from the top of the lower cell module, thus cooling the tabs and electrodes on the top of the lower cell module. During battery pack assembly, the solid-liquid phase change heat dissipation medium can be liquefied first, filling the gaps and grooves on the top of the lower cell module, and then solidified. This solidified medium allows for full contact with the heat-generating parts on the top of the lower cell module. Therefore, the transformation from solid to liquid effectively cools the top of the cell, improving the overall temperature uniformity of the cell and ensuring that the temperature detected by the temperature sensor accurately reflects the overall temperature of the cell. Because the density of the solid-liquid phase change heat dissipation medium is less than that of the single-phase coolant, it always floats above the single-phase coolant in the flow channels between the cells of the lower cell module. Furthermore, the solid-liquid phase change heat dissipation medium is blocked by a baffle, allowing it to accumulate at the top of the lower cell module for heat dissipation. The baffle also separates the single-phase coolant in the flow channels between the cells above it from the solid-liquid phase change heat dissipation medium below it, preventing the single-phase coolant above the baffle from scouring and carrying away the solid-liquid phase change heat dissipation medium below it. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the internal structure of a battery pack according to one embodiment.

[0019] Figure 2 for Figure 1 A schematic diagram showing the connection between the top of the battery module and the heat dissipation component.

[0020] Explanation of reference numerals: Y, first direction; X, second direction; 10, battery cell module; 12, lower battery cell module; 100, battery cell; 101, flow channel; 200, heat dissipation component; 210, baffle; 211, partition; 212, enclosure; 220, thermally conductive metal layer. Detailed Implementation

[0021] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0022] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0023] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0024] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0025] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0026] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0027] Please refer to Figure 1 This application provides a battery pack, which includes at least two groups of cell modules 10 arranged along a first direction Y, such as two groups, three groups, four groups, etc. Combined with... Figure 2 Each battery cell module 10 includes a plurality of battery cells 100 arranged along a second direction X, and a flow channel 101 for single-phase coolant flow is provided between adjacent battery cells 100 along the second direction X. The first direction Y is a vertical direction, and the second direction X is perpendicular to the first direction Y. Those skilled in the art typically refer to the end of the battery cell with the tab as the top of the battery cell. In the embodiments of this application, the top of the battery cell 100 is the top of the battery cell 100 along the first direction Y.

[0028] The specific design of the flow channel 101 between adjacent cells 100 for supplying single-phase coolant can be referred to the prior art, and will not be described in detail here.

[0029] In two adjacent sets of battery cell modules 10, the one located on the upper side is called the upper battery cell module, and the one located on the lower side is called the lower battery cell module 12. A heat dissipation assembly 200 is provided between the two adjacent sets of battery cell modules 10. The heat dissipation assembly 200 includes a baffle 210 and a solid-liquid phase change heat dissipation medium. The baffle 210 is attached to the bottom of the upper battery cell module in the two adjacent sets of battery cell modules 10. The solid-liquid phase change heat dissipation medium is filled between the lower side of the baffle 210 and the top of the lower battery cell module 12 in the two adjacent sets of battery cell modules 10. The density of the solid-liquid phase change heat dissipation medium is less than the density of the single-phase coolant. The solid-liquid phase change heat dissipation medium can undergo a phase change between solid and liquid states when the temperature changes. It can change from solid to liquid when the temperature rises and from liquid to solid when the temperature falls. Preferably, the solid-liquid phase change heat dissipation medium is paraffin wax.

[0030] The aforementioned battery pack operates at a low temperature when not in use, with the solid-liquid phase change heat dissipation medium in a solid state. During operation, as heat is generated in various parts of the battery pack, the solid-liquid phase change heat dissipation medium absorbs heat from the top of the lower cell module 12, transforming into a liquid state. The latent heat generated during this transition from solid to liquid phase absorbs heat from the top of the lower cell module 12, thus cooling the tabs and electrodes on the top of the lower cell module 12. During battery pack assembly, the solid-liquid phase change heat dissipation medium can be liquefied to fully fill the gaps and grooves on the top of the lower cell module 12, and then solidified. This solidified medium allows for thorough contact with the heat-generating parts on the top of the lower cell module 12. Therefore, the transformation from solid to liquid by the solid-liquid phase change heat dissipation medium effectively cools the top of the cell, thereby improving the overall temperature uniformity of the cell 100 and ensuring that the temperature detected by the temperature sensor accurately reflects the overall temperature of the cell. Because the density of the solid-liquid phase change heat dissipation medium is less than that of the single-phase coolant, the solid-liquid phase change heat dissipation medium always floats above the single-phase coolant in the flow channel 101 between the cells 100 of the lower cell module 12. Furthermore, the solid-liquid phase change heat dissipation medium is blocked by the baffle 210, thus allowing it to always accumulate at the top of the lower cell module 12 for heat dissipation. Moreover, the baffle 210 can separate the single-phase coolant in the flow channel between the cells 100 above it from the solid-liquid phase change heat dissipation medium below it, preventing the single-phase coolant in the flow channel between the cells 100 above the baffle 210 from scouring and carrying away the solid-liquid phase change heat dissipation medium below it.

[0031] like Figure 2 As shown, the battery pack includes a cell support 300, and the cell 100 is connected to the cell support 300 to support and position the cell 100.

[0032] refer to Figure 2 In one embodiment, the baffle 210 includes a partition 211 and a surrounding plate 212. The partition 211 is attached to the bottom of the upper battery cell module in two adjacent battery cell modules 10. The solid-liquid phase change heat dissipation medium is filled between the lower side of the partition 211 and the top of the lower battery cell module 12 in two adjacent battery cell modules 10. The surrounding plate 212 is connected to the outer edge of the partition 211 and protrudes downward from the partition 211 to surround the periphery of the solid-liquid phase change heat dissipation medium.

[0033] Since the outer edge of the enclosure 212 is connected to the outer edge of the partition 211 and protrudes downward from the partition 211, the enclosure 212 surrounds the periphery of the solid-liquid phase change heat dissipation medium, preventing the solid-liquid phase change heat dissipation medium from flowing away from the outer edge of the partition 211, and more reliably ensuring that it is gathered on the top of the lower cell module 12 for heat dissipation.

[0034] Preferably, the enclosure 212 completely surrounds the partition 211 in the circumferential direction to reliably contain the solid-liquid phase change heat dissipation medium.

[0035] In one embodiment, the lower end of the enclosure 212 is at a lower height than the lower end of the solid-liquid phase change heat dissipation medium in the corresponding heat dissipation assembly 200.

[0036] Because the density of the solid-liquid phase change heat dissipation medium is less than that of the single-phase coolant, the solid-liquid phase change heat dissipation medium always floats above the single-phase coolant in the flow channel 101 between the cells 100 of the lower cell module 12. The lower end of the enclosure plate 212 is lower than the lower end of the solid-liquid phase change heat dissipation medium. Therefore, the lower end of the floating solid-liquid phase change heat dissipation medium is contained by the enclosure plate 212, thus reliably ensuring that the solid-liquid phase change heat dissipation medium remains inside the enclosure plate 212 and preventing its leakage.

[0037] In one embodiment, the height of the upper surface of the outer shell of the cell 100 of the lower cell module 12 in two adjacent sets of cell modules 10 is higher than the height of the lower end of the enclosure 212 in the corresponding heat dissipation assembly 200. That is, the lower end of the enclosure 212 extends to the lower side of the upper surface of the outer shell of the cell 100 of the lower cell module 12, thereby enabling the enclosure 212 to more reliably ensure that the solid-liquid phase change heat dissipation medium is inside the enclosure 212 and prevent its leakage.

[0038] In other embodiments, the height of the upper surface of the outer shell of the cell 100 of the lower cell module 12 in two adjacent cell modules 10 can also be equal to (or lower than) the height of the lower end of the enclosure 212 in the corresponding heat dissipation assembly 200. This is only necessary as long as the height of the lower end of the enclosure 212 is lower than the height of the lower end of the solid-liquid phase change heat dissipation medium in the corresponding heat dissipation assembly 200.

[0039] In one embodiment, the projections of the upper and lower cell modules 12 in two adjacent sets of cell modules 10 toward the baffle 210 along the first direction Y are completely located within the baffle 210. That is, the baffle 210 can completely cover the top of the lower cell module 12, so that the solid-liquid phase change heat dissipation medium below the baffle 210 can dissipate heat from the top of all the cells 100 of the lower cell module 12. Moreover, the baffle 210 can effectively separate the coolant in the flow channel between the cells 100 on its upper side from the solid-liquid phase change heat dissipation medium on its lower side.

[0040] Preferably, the projections of the upper and lower battery modules 12 in two adjacent battery modules 10 toward the baffle 210 along the first direction Y are completely located within the partition 211, and the enclosure 212 can reliably enclose the solid-liquid phase change heat dissipation medium below the partition 211.

[0041] In one embodiment, the baffle 210 is a liquid-cooled plate with internal channels for coolant flow. Since the baffle 210 is attached to the bottom of the upper cell module in the two adjacent cell modules 10, the baffle 210 (i.e., the liquid-cooled plate) can dissipate heat from the bottom of the upper cell module. Furthermore, the baffle 210 can be fixed relative to the cell support 300, thus providing support for the upper cell module.

[0042] Furthermore, since the solid-liquid phase change heat dissipation medium is filled between the lower side of the baffle 210 and the top of the lower cell module 12 in the two adjacent sets of cell modules 10, when the solid-liquid phase change heat dissipation medium absorbs the heat from the top of the lower cell module 12 and converts into a liquid state, the heat can be transferred to the baffle 210 (i.e., the liquid cooling plate) and carried away by the coolant in the baffle 210, thereby enabling the solid-liquid phase change heat dissipation medium to always be in a stable two-phase state.

[0043] Understandably, when the baffle 210 is a liquid cooling plate, an inlet and an outlet can be provided on the liquid cooling plate. Coolant is introduced into the liquid cooling plate through the inlet and flows out from the outlet.

[0044] refer to Figure 2 In one embodiment, the heat dissipation component 200 further includes a thermally conductive metal layer 220, which is attached to the lower surface of the baffle 210. The heat absorbed by the solid-liquid phase change heat dissipation medium when it changes from solid to liquid can be transferred to the thermally conductive metal layer 220 and then to the liquid cooling plate, thereby quickly removing the heat absorbed by the solid-liquid phase change heat dissipation medium.

[0045] Preferably, the thermally conductive metal layer has a porous metal structure. The porous structure allows the liquid solid-liquid phase change heat dissipation medium to be fully wetted and in full contact with the thermally conductive metal layer, thereby enabling rapid heat transfer to the baffle 210. Porous metal structures include, for example, foamed copper and foamed aluminum.

[0046] In other embodiments, the thermally conductive metal layer can also be a mesh structure with multiple mesh openings, such as a copper mesh. The mesh structure also allows the liquid solid-liquid phase change heat dissipation medium to have sufficient contact with the thermally conductive metal layer, thereby enabling rapid heat transfer to the baffle 210.

[0047] In one embodiment, the thermally conductive metal layer 220 is attached to the lower surface of the partition 211.

[0048] In one embodiment, the top of the lower cell module 12 in two adjacent sets of cell modules 10 is spaced apart from the thermally conductive metal layer 220 in the corresponding heat dissipation assembly 200 to meet the requirements of electrical safety.

[0049] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0050] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A battery pack, characterized in that, The battery pack includes: at least two sets of cell modules arranged along a first direction, each set of cell modules including a plurality of cells arranged along a second direction, and a flow channel for single-phase coolant to flow between adjacent cells along the second direction; wherein, the first direction is a vertical direction, and the second direction is perpendicular to the first direction. A heat dissipation assembly is provided between two adjacent sets of battery cell modules. The heat dissipation assembly includes a baffle and a solid-liquid phase change heat dissipation medium. The baffle is attached to the bottom of the upper battery cell module in the two adjacent sets of battery cell modules. The solid-liquid phase change heat dissipation medium is filled between the lower side of the baffle and the top of the lower battery cell module in the two adjacent sets of battery cell modules. The density of the solid-liquid phase change heat dissipation medium is less than the density of the single-phase coolant.

2. The battery pack according to claim 1, characterized in that, The baffle includes a partition and a surrounding plate. The partition is attached to the bottom of the upper battery cell module in two adjacent battery cell modules. The solid-liquid phase change heat dissipation medium is filled between the lower side of the partition and the top of the lower battery cell module in two adjacent battery cell modules. The surrounding plate is connected to the outer edge of the partition and protrudes downward from the partition to surround the solid-liquid phase change heat dissipation medium.

3. The battery pack according to claim 2, characterized in that, The lower end of the enclosure is at a lower height than the lower end of the solid-liquid phase change heat dissipation medium in the corresponding heat dissipation assembly.

4. The battery pack according to claim 2, characterized in that, In two adjacent sets of battery cell modules, the height of the upper surface of the outer shell of the lower battery cell module is higher than or equal to the height of the lower end of the enclosure plate in the corresponding heat dissipation assembly.

5. The battery pack according to claim 1, characterized in that, The projections of the upper and lower battery cell modules in two adjacent sets of battery cell modules toward the baffle along the first direction are completely located within the baffle.

6. The battery pack according to claim 1, characterized in that, The baffle is a liquid-cooled plate with a channel inside for coolant to flow through.

7. The battery pack according to claim 6, characterized in that, The heat dissipation component also includes a thermally conductive metal layer, which is attached to the lower surface of the baffle.

8. The battery pack according to claim 7, characterized in that, The thermally conductive metal layer has multiple mesh holes; or, the thermally conductive metal layer is a porous metal structure.

9. The battery pack according to claim 7, characterized in that, In two adjacent groups of battery cell modules, the top of the lower battery cell module is spaced apart from the thermally conductive metal layer in the corresponding heat dissipation assembly.

10. The battery pack according to claim 1, characterized in that, The solid-liquid phase change heat dissipation medium is paraffin wax.

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