Battery pack

Abstract

This application provides a battery pack comprising: a heat-conducting plate for heat conduction; a heat spreader and a battery cell, the battery cell having a top surface, a bottom surface opposite to the top surface, and an outer surface connecting the top and bottom surfaces; the heat spreader is attached to the outer surface, extending between the top and bottom surfaces and covering at least a portion of the outer surface; the heat spreader transfers heat between the area of ​​the outer surface near the top surface and the area of ​​the outer surface near the bottom surface; the heat-conducting plate is connected to the bottom surface. By attaching a heat spreader to the outer surface of the battery cell, the high thermal conductivity of the heat spreader can be utilized to transfer heat between the area of ​​the outer surface near the top surface and the area of ​​the outer surface near the bottom surface, thereby achieving temperature uniformity of the battery cell and avoiding a large temperature difference between the end of the battery cell near the heat spreader and the end away from the heat spreader, thus improving the cycle life and environmental adaptability of the battery pack.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more specifically, to a battery pack. Background Technology

[0002] In related technologies, there are generally two methods for cooling battery packs: the first is to dissipate heat through air cooling, which relies on rapid airflow for heat exchange but has a poor heat dissipation effect; the second is to cool the battery pack by arranging liquid cooling plates around the cells, which improves the heat dissipation effect because the liquid cooling plates are in direct contact with the cells.

[0003] However, for the second cooling method, when the liquid cooling plate is placed on the top or surface of the cell, there are risks of high mold costs for the liquid cooling plate and poor airtightness of the battery pack. To overcome these problems, some practices place the liquid cooling plate at the bottom of the cell to cool it. However, with this approach, the bottom of the cell is close to the liquid cooling plate and its temperature is usually lower, while the top of the cell is far from the liquid cooling plate and its temperature is higher. This results in a large temperature difference between the top and bottom of the cell, which will reduce the cycle life of the battery pack and make the battery pack unsuitable for high charge / discharge rates and high heat generation and power consumption scenarios. Utility Model Content

[0004] The purpose of this application is to provide a battery pack that improves both cycle life and environmental adaptability.

[0005] This application provides a battery pack comprising:

[0006] Heat-conducting plates used for heat transfer;

[0007] Heat spreader; and

[0008] A battery cell has a top surface, a bottom surface opposite to the top surface, and an outer surface connecting the top surface and the bottom surface; a heat spreader is attached to the outer surface, the heat spreader extends between the top surface and the bottom surface, and covers at least a portion of the outer surface; the heat spreader transfers heat between a region of the outer surface near the top surface and a region of the outer surface near the bottom surface; a heat-conducting plate is connected to the bottom surface.

[0009] In one embodiment, the heat spreader is a graphite heat spreader; the thickness of the heat spreader is h1, 15μm≤h1≤50μm, and / or the planar thermal conductivity of the heat spreader is greater than or equal to 1500W / mK.

[0010] In one embodiment, the heat spreader is a VC heat spreader; the thickness of the heat spreader is h1, 0.23mm≤h1≤0.5mm, and / or the planar thermal conductivity of the heat spreader is greater than or equal to 20000W / mK.

[0011] In one embodiment, the heat spreader and the heat conduction plate are spaced apart. The heat spreader has an upper edge near the top surface and a lower edge near the bottom surface. The distance between the upper edge and the top surface is d1, and the distance between the lower edge and the bottom surface is d2, where 0≤d1≤5mm and 0≤d2≤5mm.

[0012] In one embodiment, the battery cell is a cubic battery cell, and the outer surface includes two large surfaces and two side surfaces arranged opposite to each other. The heat spreader is attached to both large surfaces, and / or the heat spreader is attached to both side surfaces.

[0013] In one embodiment, there are multiple battery cells, which are stacked in a direction perpendicular to the large surface, and a heat insulation pad is provided between any two adjacent battery cells.

[0014] In one embodiment, the heat spreader is bonded to the exterior surface by a high-temperature resistant adhesive layer; and / or, the battery pack includes a thermally conductive adhesive layer, and the heat-conducting plate is bonded to the bottom surface by the thermally conductive adhesive layer.

[0015] In one embodiment, the heat-conducting plate has a flow channel inside for the heat-conducting medium to circulate; the heat-conducting plate is a liquid-cooled plate or a heating plate.

[0016] In one embodiment, the heat-conducting plate is connected to an inlet connector and an outlet connector, both of which are in communication with the flow channel.

[0017] In one embodiment, the battery cell is a cubic battery cell, the outer surface includes two large surfaces and two side surfaces arranged opposite each other, there are multiple battery cells, and the multiple battery cells are stacked in a direction perpendicular to the large surfaces; the liquid inlet connector and the liquid outlet connector are located on the same side of the heat-conducting plate in a direction perpendicular to the large surfaces.

[0018] The beneficial effects of the battery pack provided in this application embodiment are as follows: Compared with related technologies, the battery pack provided in this application, by attaching a heat spreader to the outer surface of the battery cell, can utilize the high thermal conductivity of the heat spreader to transfer heat between the area near the top surface and the area near the bottom surface of the outer surface of the battery cell, thereby achieving a better temperature uniformity for the battery cell and avoiding a large temperature difference between the end of the battery cell near the heat spreader and the end away from the heat spreader, thus improving the cycle life and environmental adaptability of the battery pack. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the battery pack structure provided in an embodiment of this application;

[0021] Figure 2 for Figure 1 The diagram shows the structure of the battery pack at another time.

[0022] Figure 3 for Figure 2 The diagram shown is an exploded view of the battery pack structure.

[0023] Figure 4 for Figure 3 Enlarged structural diagram at point A;

[0024] Figure 5 for Figure 3 Enlarged structural diagram at point B;

[0025] The following are the labeling elements in the figure:

[0026] 10. Battery pack; 110. Heat-conducting plate; 120. Heat spreader; 121. Top edge; 122. Bottom edge; 130. Battery cell; 131. Top surface; 132. Bottom surface; 133. Exterior facade; 134. Main surface; 135. Side surface; 136. Terminal post; 140. Heat insulation pad; 150. Thermally conductive adhesive layer; 160. Liquid inlet connector; 170. Liquid outlet connector. Detailed Implementation

[0027] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0028] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0029] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They 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. Therefore, they should not be construed as limitations on this application.

[0030] Furthermore, the terms "first" and "second" are used 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 as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0031] Please refer to the following: Figures 1 to 5 The battery pack 10 provided in this application embodiment will now be described. The battery pack 10 includes a heat-conducting plate 110, a heat spreader 120, and a battery cell 130. The heat-conducting plate 110 is used for heat conduction. The battery cell 130 has a top surface 131, a bottom surface 132 opposite to the top surface 131, and an outer surface 133 connecting the top surface 131 and the bottom surface 132. The heat spreader 120 is attached to the outer surface 133, extending between the top surface 131 and the bottom surface 132, and covering at least a portion of the outer surface 133. The heat spreader 120 transfers heat between the area of ​​the outer surface 133 near the top surface 131 and the area of ​​the outer surface 133 near the bottom surface 132. The heat-conducting plate 110 is connected to the bottom surface 132 and is spaced apart from the heat spreader 120.

[0032] It can be understood that for the battery cell 130, the side with the terminal post 136 is the top surface 131, and the side opposite the top surface 131 is the bottom surface 132. The direction from the bottom surface 132 to the top surface 131 is the height direction of the battery cell 130. In this application, the battery cell 130 can be a cubic battery cell 130, that is, the battery cell 130 is generally cubic in shape, and the other four planes on the battery cell 130, excluding the top surface 131 and the bottom surface 132, together constitute the outer surface 133 of the battery cell 130. Alternatively, in other embodiments, the battery cell 130 can be a cylindrical battery cell 130, that is, the battery cell 130 is generally cylindrical in shape, and the cylindrical surface on the battery cell 130, excluding the top surface 131 and the bottom surface 132, is the outer surface 133 of the battery cell 130.

[0033] It is understandable that, since the heat-conducting plate 110 is connected to the bottom surface 132, the area on the outer facade 133 near the top surface 131 is away from the heat-conducting plate 110, while the area on the outer facade 133 near the bottom surface 132 is close to the heat-conducting plate 110. The extension of the heat spreader 120 between the top surface 131 and the bottom surface 132 can be understood as the heat spreader 120 extending along the height direction of the battery cell 130, with one end close to the top surface 131 and the other end close to the bottom surface 132. In this way, the heat spreader 120 can transfer heat between the area on the outer facade 133 near the top surface 131 and the area on the outer facade 133 near the bottom surface 132, so as to achieve a uniform temperature of the battery cell 130, avoid a large temperature difference between the two ends of the battery cell 130 along the height direction, and thus improve the cycle life of the battery cell 130. With the temperature equalization effect of the heat spreader 120 on the battery cell 130, the temperature of the battery cell 130 will not be too high or too low, making it suitable for scenarios with high charge-discharge rate and high heat generation and power consumption.

[0034] Compared with related technologies, the battery pack 10 provided in this application, by attaching a heat spreader 120 to the outer surface 133 of the cell 130, can utilize the high thermal conductivity of the heat spreader 120 to transfer heat between the area near the top surface 131 and the area near the bottom surface 132 of the outer surface 133 of the cell 130. This provides better heat dissipation for the cell 130 and avoids a large temperature difference between the end of the cell 130 near the heat spreader 110 and the end away from the heat spreader 110, thereby improving the cycle life and environmental adaptability of the battery pack 10.

[0035] Specifically, in this application, the heat spreader 120 is a graphite heat spreader, that is, the material of the heat spreader 120 is graphite, so the heat spreader 120 has high thermal conductivity.

[0036] In this application, the thickness of the heat spreader 120 is h1, where 15μm≤h1≤50μm, and the planar thermal conductivity of the heat spreader 120 is greater than or equal to 1500W / mK. It can be understood that the heat spreader 120 can be made from a special polyimide film as raw material using high-temperature synthesis technology, becoming a novel high-thermal-conductivity heat dissipation structure with high crystallinity, high grain orientation, and low lattice defects. Thus, the heat spreader 120 can achieve a better temperature uniformity effect for the battery cell 130.

[0037] In other embodiments, the heat spreader 120 can also be a VC heat spreader, i.e., a vacuum chamber heat spreader. The thickness of the heat spreader 120 is h1, 0.23mm≤h1≤0.5mm, and the planar thermal conductivity of the heat spreader 120 is greater than or equal to 20000W / mK.

[0038] Combination Figures 1 to 5As shown, the heat spreader 120 and the heat conduction plate 110 are spaced apart. The heat spreader 120 has an upper edge 121 near the top surface 131 and a lower edge 122 near the bottom surface 132. The distance between the upper edge 121 and the top surface 131 is d1, and the distance between the lower edge 122 and the bottom surface 132 is d2. 0≤d1≤5mm, 0≤d2≤5mm.

[0039] It is understandable that by setting the heat spreader 120 and the heat conduction plate 110 at intervals, interference between their installation can be avoided.

[0040] It is understandable that the upper edge 121 is flush with the top surface 131, while the lower edge 122 is located between the top surface 131 and the bottom surface 132; or, the lower edge 122 is flush with the bottom surface 132, while the upper edge 121 is located between the top surface 131 and the bottom surface 132; or, the lower edge 122 is flush with the bottom surface 132, while the upper edge 121 is flush with the top surface 131; or, both the lower edge 122 and the upper edge 121 are located between the top surface 131 and the bottom surface 132, but not flush with either of them.

[0041] This configuration ensures that the distance between the lower edge 122 and the upper edge 121 of the heat spreader 120 (i.e., the height of the heat spreader 120) is less than or equal to the distance between the top surface 131 and the bottom surface 132 of the battery cell 130 (i.e., the height of the battery cell 130). This allows the heat spreader 120 to be fully attached to the outer surface 133 without extending beyond the outer perimeter of the top surface 131 and the bottom surface 132 in the height direction of the battery cell 130. This prevents the heat spreader 120 from interfering with the components to be installed on the top surface 131 and the bottom surface 132 of the battery cell 130. Furthermore, since the distance between the upper edge 121 and the top surface 131 is less than or equal to 5 mm, and the distance between the lower edge 122 and the bottom surface 132 is less than or equal to 5 mm, the upper edge 121 is closer to the top surface 131 and the lower edge 122 is closer to the bottom surface 132, which can ensure that the heat spreader 120 plays a better role in heat spreader for both ends of the battery cell 130 along the height direction.

[0042] Combination Figures 1 to 5 As shown in this embodiment, the battery cell 130 is a cubic battery cell 130. The outer surface 133 includes two large surfaces 134 and two side surfaces 135 arranged opposite each other. A heat spreader 120 is attached to each of the two large surfaces 134. In other embodiments, a heat spreader 120 may be attached to both side surfaces 135, but not to the two large surfaces 134. Alternatively, in other embodiments, a heat spreader 120 may be attached to both side surfaces 135 and both large surfaces 134. This arrangement allows the heat spreaders 120 to be symmetrically arranged on the surface of the battery cell 130, thereby achieving a better temperature uniformity effect on the battery cell 130.

[0043] Specifically, in this application, the heat spreader 120 is bonded to the exterior surface 133 by a high-temperature resistant adhesive layer (not shown). It can be understood that the high-temperature resistant adhesive layer can stably adhere the heat spreader 120 to the exterior surface 133, ensuring that the heat spreader 120 achieves a good temperature uniformity effect on the battery cell 130.

[0044] Combination Figures 1 to 5 As shown in this application, there are multiple battery cells 130, which are stacked along a direction perpendicular to the large surface 134. A heat insulation pad 140 is provided between any two adjacent battery cells 130. By providing the heat insulation pad 140, two battery cells 130 can be separated to prevent heat conduction between adjacent battery cells 130, avoiding excessive heat transfer from one battery cell 130 to adjacent battery cells 130, making the temperature distribution within the battery pack 10 more uniform, preventing local overheating, and improving the safety of the battery pack 10. Specifically, since a heat spreader 120 is attached to the large surface 134 of the battery cell 130, the heat insulation pad 140 is clamped between the heat spreaders 120 attached to the large surface 134 of two adjacent battery cells 130.

[0045] The shape and size of the heat insulation pad 140 can be consistent with the shape and size of the heat spreader 120, or the edge of the heat insulation pad 140 can extend beyond the heat spreader 120, so that the two heat spreaders 120 located on both sides of the heat insulation pad 140 can also be completely separated by the heat insulation pad 140.

[0046] In this application, the battery pack 10 includes a thermally conductive adhesive layer 150, and the heat-conducting plate 110 is adhered to the bottom surface 132 through the thermally conductive adhesive layer 150. Specifically, the thermally conductive adhesive layer 150 can be a thermally conductive structural adhesive.

[0047] The heat-conducting plate 110 has an internal flow channel (not shown) for the flow of a heat-conducting medium. The heat-conducting plate 110 can be either a liquid-cooled plate or a heating plate. It can be understood that when a low-temperature heat-conducting medium is introduced into the flow channel, the heat-conducting plate 110 can be used as a liquid-cooled plate, where the heat-conducting medium absorbs heat from the battery cell 130 and dissipates the heat, thus cooling the battery cell 130. Conversely, when a high-temperature heat-conducting medium is introduced into the flow channel, the heat-conducting plate 110 can be used as a heating plate, where the heat from the heat-conducting medium is conducted to the battery cell 130 to raise its temperature. Thus, the temperature of the heat-conducting medium in the flow channel can be adjusted as needed. When the liquid cooling system is cooling at high temperature, heat is conducted from the high-temperature area at the top to the low-temperature area at the bottom; when the liquid cooling system is heating at low temperature, heat is conducted from the high-temperature area at the bottom to the low-temperature area at the top. This allows the heat-conducting plate 110 to adjust the temperature of the battery cell 130, ensuring that the battery cell 130 operates within a suitable temperature range and preventing the battery cell 130 from becoming too hot or too cold, which could affect its cycle life.

[0048] In this embodiment, the heat-conducting plate 110 is connected to an inlet connector 160 and an outlet connector 170, both of which are connected to the flow channel. External pipelines can be connected to the heat-conducting plate 110 through the inlet connector 160 and the outlet connector 170, thereby supplying and discharging the heat-conducting medium to the heat-conducting plate 110.

[0049] Furthermore, when multiple battery cells 130 are stacked in a direction perpendicular to the large surface 134, the liquid inlet connector 160 and the liquid outlet connector 170 are located on the same side of the heat-conducting plate 110 in the direction perpendicular to the large surface 134. This arrangement allows for a more rational layout of the battery pack 10, which helps to fully utilize the internal space of the battery pack 10.

[0050] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A battery pack, characterized in that, include: Heat-conducting plates used for heat transfer; Heat spreader; and A battery cell has a top surface, a bottom surface opposite to the top surface, and an outer surface connecting the top surface and the bottom surface; a heat spreader is attached to the outer surface, the heat spreader extends between the top surface and the bottom surface, and covers at least a portion of the outer surface; the heat spreader transfers heat between a region of the outer surface near the top surface and a region of the outer surface near the bottom surface; a heat-conducting plate is connected to the bottom surface.

2. The battery pack according to claim 1, characterized in that, The heat spreader is a graphite heat spreader; the thickness of the heat spreader is h1, 15μm≤h1≤50μm, and / or the planar thermal conductivity of the heat spreader is greater than or equal to 1500 W / mK.

3. The battery pack according to claim 1, characterized in that, The heat spreader is a VC heat spreader; the thickness of the heat spreader is h1, 0.23mm≤h1≤0.5mm, and / or the planar thermal conductivity of the heat spreader is greater than or equal to 20000 W / mK.

4. The battery pack according to claim 1, characterized in that, The heat spreader and the heat conduction plate are spaced apart. The heat spreader has an upper edge near the top surface and a lower edge near the bottom surface. The distance between the upper edge and the top surface is d1, and the distance between the lower edge and the bottom surface is d2. 0≤d1≤5mm, 0≤d2≤5mm.

5. The battery pack according to claim 1, characterized in that, The battery cell is a square battery cell, and the outer surface includes two large surfaces and two side surfaces arranged opposite to each other. The heat spreader is attached to both large surfaces, and / or the heat spreader is attached to both side surfaces.

6. The battery pack according to claim 5, characterized in that, There are multiple battery cells, which are stacked in a direction perpendicular to the large surface, and a heat insulation pad is provided between any two adjacent battery cells.

7. The battery pack according to claim 1, characterized in that, The heat spreader is bonded to the exterior surface by a high-temperature resistant adhesive layer; and / or, the battery pack includes a thermally conductive adhesive layer, and the heat-conducting plate is bonded to the bottom surface by the thermally conductive adhesive layer.

8. The battery pack according to claim 1, characterized in that, The heat-conducting plate has internal channels for the flow of heat-conducting medium; the heat-conducting plate is a liquid-cooled plate or a heating plate.

9. The battery pack according to claim 8, characterized in that, The heat-conducting plate is connected to a liquid inlet connector and a liquid outlet connector, both of which are connected to the flow channel.

10. The battery pack according to claim 9, characterized in that, The battery cell is a cube-shaped battery cell. The outer surface includes two large surfaces and two side surfaces arranged opposite each other. There are multiple battery cells, which are stacked in a direction perpendicular to the large surfaces. The liquid inlet connector and the liquid outlet connector are located on the same side of the heat-conducting plate in a direction perpendicular to the large surfaces.

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