Battery cell group, battery pack, and electrical device

Abstract

The present application provides a battery cell group and a battery pack. The battery cell group comprises at least one battery cell, and a cooling member. Each battery cell has a first portion provided with a terminal post, and a side portion connected to one side of the first portion. The cooling member is used for cooling the at least one battery cell, and comprises a first plate and a side plate connected to one side of the first plate. The first plate abuts against the first portion of the at least one battery cell, and the side plate abuts against the side portion of the at least one battery cell.

Description

Battery cells, battery packs and electrical equipment

[0001] This application claims priority to Chinese Patent Application No. 202422950134.1, filed with the Chinese Patent Office on November 29, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of batteries, specifically to a battery cell assembly, a battery pack, and an electrical device. Background Technology

[0003] Currently, the cooling technology for battery cells in electric vehicles and other battery-powered devices typically involves installing a cooling device at the bottom of the cell assembly to control the cell assembly's temperature. This method is effective in reducing the overall battery temperature in most cases. Invention Overview

[0004] When the battery pack is in a fast charging state, installing a cooling device at the bottom of the battery pack is not ideal for cooling. Experimental verification shows that when the battery pack is in a fast charging state, the area with the highest internal temperature of the battery cell is usually near the tabs of the cell. When the tabs of the battery cell are not located at the bottom of the cell, the above-mentioned cooling method cannot effectively cool the battery pack.

[0005] Therefore, this application adopts the following technical solution:

[0006] In a first aspect, embodiments of this application provide a battery cell assembly, comprising: at least one battery cell, each battery cell having a first portion and a side portion connected to one side of the first portion, each battery cell including an electrode post disposed in the first portion; and a cooling member for cooling at least one battery cell, including a first plate and a side plate connected to one side of the first plate; wherein the first plate abuts against the first portion of at least one battery cell, and the side plate abuts against the side portion of at least one battery cell.

[0007] Secondly, embodiments of this application provide a battery pack that includes the cell assembly of the first aspect.

[0008] Thirdly, embodiments of this application provide an electrical device that includes the battery pack of the second aspect. Beneficial effects

[0009] The battery cell assembly provided in this application includes at least one battery cell and a cooling component. Each battery cell has a first portion with terminals and a side portion connected to one side of the first portion. The cooling component is used to cool at least one battery cell and includes a first plate and a side plate connected to one side of the first plate. The first plate abuts against the first portion of at least one battery cell, and the side plate abuts against the side portion of at least one battery cell. The battery cell assembly provided in this application, by thermally connecting the first plate and the side plate to the first portion and side portion of the battery cell respectively, allows the cooling plate to cool the areas of the battery cell assembly with higher temperatures during fast charging, thereby effectively reducing the risk of localized overheating of the battery cell assembly.

[0010] The battery pack provided in this application has all the advantages of the aforementioned cell pack.

[0011] The electrical equipment provided in this application has all the advantages of the aforementioned battery pack. Attached Figure Description

[0012] Figure 1 is a schematic diagram of the battery pack provided in an embodiment of this application;

[0013] Figure 2 is an exploded view of Figure 1;

[0014] Figure 3 is a top view of the battery cell assembly in Figure 1;

[0015] Figure 4 is an enlarged perspective view of part A in Figure 3;

[0016] Figure 5 is a front view of the battery cell assembly in Figure 1;

[0017] Figure 6 is a top view of multiple battery cells in Figure 2;

[0018] Figure 7 is an enlarged perspective view of part B in Figure 6;

[0019] Figure 8 is a side view of multiple battery cells in Figure 2.

[0020] Explanation of reference numerals in the attached figures:

[0021] 100, Cell assembly; 110, Cell; 120, Cooling component; 210, First part; 220, Side part; 230, Terminal post; 240, First plate; 250, Side plate; 260, Cell body; 270, Insulating film; 280, First window opening; 290, Second window opening. Embodiments of the present invention

[0022] Experimental verification shows that when the battery cell assembly is in fast charging mode, the areas with higher internal temperatures are usually distributed at and near the battery tabs. The tabs of some cells (such as square cells) are usually located on the side of the cell and in the area where the terminal block meets the side. In related technologies, cooling components are usually located at the bottom of the battery cell assembly, so the above-mentioned cells cannot be effectively cooled.

[0023] To address the problem of unsatisfactory cooling effect of battery cell assemblies in the aforementioned related technologies, embodiments of this application provide a battery cell assembly 100. Please refer to Figures 1 and 2. Figure 1 is a structural schematic diagram of the battery cell assembly 100 provided in this application embodiment, and Figure 2 is an exploded view of Figure 1. The battery cell assembly 100 includes at least one battery cell 110 and a cooling element 120, which is used to cool the battery cell 110. Specifically, the battery cell 110 includes a first portion 210 and a side portion 220 connected to one side of the first portion 210. A terminal post 230 of the battery cell 110 is disposed in the first portion 210 of the battery cell 110. A tab (not shown in the figure) of the battery cell 110 is disposed in the first portion 210 and the side portion 220, and is electrically connected to the terminal post 230. The cooling component 120 includes a first plate 240 and a side plate 250 connected to one side of the first plate 240. The first plate 240 abuts against the first part 210 of the battery cell 110, and the side plate 250 abuts against the side part 220 of the battery cell 110, so that the first plate 240 and the side plate 250 are thermally connected to the first part 210 and the side part 220 of the battery cell 110, respectively, so as to cool the first part 210 and the side part 220 of the battery cell 110, respectively.

[0024] In this embodiment, by thermally connecting the first plate 240 and the side plate 250 to the first part 210 and the side part 220 of the battery cell 110 respectively, the cooling plate can cool the parts of the battery cell assembly 100 that have high temperature in the fast charging state, thereby effectively reducing the risk of local overheating of the battery cell assembly 100.

[0025] It should be noted that the cooling element 120 provided in this application dissipates heat from the battery cell 110 by circulating a cooling medium. The cooling channel for circulating the cooling medium can be implemented in various ways. For example, the inlet and outlet of the cooling medium can be located on the same side of the extending direction of the cooling element 120, or on different sides of the extending direction of the cooling element 120. In the embodiments provided in this application, the cooling channel can take different forms such as straight, curved, or spiral, and the width and height of the channel can also be adjusted according to cooling requirements. No specific limitation is placed on the cooling channel structure of the cooling element 120.

[0026] In the embodiments provided in this application, the direction in which the first plate 240 points to the pole post 230 or the direction in which the pole post 230 points to the first plate 240 is designated as the first direction, which can be referred to as the X direction in FIG1; the arrangement direction of the plurality of cells 110 is designated as the second direction, which can be referred to as the Y direction in FIG1; and the height direction of the cells 110 is designated as the third direction, which can be referred to as the Z direction in FIG1.

[0027] It is easy to understand, referring to Figures 2 to 4. Figure 3 is a top view of the cell assembly 100 in Figure 1, and Figure 4 is an enlarged perspective view of part A in Figure 3. If the dimension L1 of the first plate 240 in the first direction is too short, it may result in poor heat dissipation of the first part 210 of the cell 110, causing the first part 210 to overheat, thereby affecting the service life and safety of the cell assembly 100. Conversely, if the dimension L1 of the first plate 240 in the first direction is too long, it may cause interference between the first plate 240 and the terminal post 230 of the cell 110 during assembly, thereby affecting the assembly efficiency of the cell assembly 100 or even making it impossible to install the cooling component 120.

[0028] In order to effectively solve the above problems and achieve a balance between the cooling efficiency of the cooling component 120 to the battery cell assembly 100 and the ease of assembly of the battery cell assembly 100, in some embodiments, the ratio of the dimension L1 of the first plate 240 in the first direction to the distance d between the pole post 230 and the side plate 250 in the first direction is set in the range of 0.8 to 1.

[0029] Experiments have shown that, on the one hand, if the ratio of L1 to d is less than 0.8, the heat conduction area between the first plate 240 of the cooling component 120 and the first part 210 of the battery cell 110 will be small, resulting in poor heat dissipation of the first part 210. On the other hand, if the ratio of L1 to d is greater than 1, the first plate 240 of the cooling component 120 will interfere with the terminal post 230 during installation, making the installation of the cooling component 120 inconvenient and potentially affecting the structural stability of the battery cell assembly 100. Therefore, setting the ratio of the dimension L1 of the first plate 240 in the first direction to the distance d between the terminal post 230 and the side plate 250 in the first direction within the range of 0.8 to 1 ensures that the dimension of the first plate 240 in the first direction is sufficient to cover the high-temperature area of ​​the first part 210, thereby ensuring good heat dissipation of the first part 210 of the battery cell 110. It also avoids interference between the first plate 240 and the terminal post 230, ensuring the ease of installation of the cooling component 120.

[0030] Similarly, the dimension L2 of the side plate 250 in the height direction of the cell 110 also affects the heat dissipation effect of the side portion 220 of the cell 110. Specifically, refer to Figures 2 and 5. Figure 5 is a front view of the cell assembly 100 in Figure 1. On the one hand, if the dimension L2 of the side plate 250 in the height direction of the cell 110 is too short, the heat conduction area between the side plate 250 of the cooling component 120 and the side portion 220 of the cell 110 will be small, resulting in poor heat dissipation effect of the side portion 220. On the other hand, the temperature of the side portion 220 of the cell 110 near the first plate 240 is higher, while the temperature of the portion farther away from the top plate is relatively lower. In the actual cooling process, the cooling effect of the cold plate is roughly the same for all positions of the side 220. If the side plate 250 is too long, the original high temperature position of the side 220 will be effectively dissipated so that the temperature of that position is within the predetermined range. The original low temperature position of the side 220 will be even lower after dissipation, resulting in a certain temperature difference between the two positions. This temperature difference will affect the cycle life and safety of the battery cell assembly 100.

[0031] To address the aforementioned issues, in some embodiments, the ratio of the dimension L2 of the side plate 250 in the height direction of the cell 110 to the height h of the cell 110 is set in the range of 0.55 to 0.65.

[0032] Experiments have shown that, on the one hand, if the ratio of the dimension L2 of the side plate 250 in the height direction of the cell 110 to the height h of the cell 110 is less than 0.55, the heat dissipation area of ​​the side plate 250 will be insufficient, and it will be unable to effectively dissipate heat from the side 220 of the cell 110. On the other hand, if the ratio of the dimension L2 of the side plate 250 in the height direction of the cell 110 to the height h of the cell 110 is greater than 0.65, the temperature distribution of the side 220 of the cell 110 will be uneven. Specifically, the temperature will be higher in the area near the top plate and lower in the area away from the top plate, resulting in a large temperature difference between the two. When the ratio of the dimension L2 of the side plate 250 in the height direction of the cell 110 to the height h of the cell 110 is set in the range of 0.55 to 0.65, it can not only ensure that the cooling effect of the side 220 of the cell 110 is good, but also effectively control the temperature difference between the upper and lower positions of the side 220 of the cell 110, thereby maintaining a uniform temperature distribution of the cell 110, reducing the potential risks caused by uneven temperature of the cell 110, and thus effectively extending the service life of the cell assembly 100.

[0033] In the above embodiments, referring to Figures 1 and 2, the cell 110 includes a cell body 260 and an insulating film 270 covering the outer surface of the cell body 260. The cooling component 120 is bonded to the insulating film 270 by thermally conductive adhesive (not shown in the figure). However, due to the insufficient bonding strength of the insulating film 270, the connection between the cell 110 and the cooling component 120 may become loose due to the vibration of the cell assembly 100 during daily use. Especially in the current mainstream CTP (Cell To Pack) battery structure, due to the lack of end plate fixation, the connection between the cell 110 and the cooling component 120 is more likely to become unstable due to the movement of the cell assembly 100, making the risk of loosening between the two greater.

[0034] Therefore, to reduce the risk of loosening of the connection between the battery cell 110 and the cooling component 120, this embodiment proposes an improved structural design. Specifically, the battery cell 110 includes a battery cell body 260 and an insulating film 270 covering the outer surface of the battery cell body 260. The insulating film 270 not only protects the battery cell 110 but also acts as an insulator between the cooling component 120 and the battery cell body 260. The insulating film 270 has a first window 280 and a second window 290, so that the first plate 240 can abut against the first part 210 of at least one battery cell 110 through the first window 280 and be bonded to the battery cell body 260 with thermally conductive adhesive. The side plate 250 can abut against the side part 220 of at least one battery cell 110 through the second window 290 and be bonded to the battery cell body 260 with thermally conductive adhesive.

[0035] In this embodiment, the structural design of the first window portion 280 and the second window portion 290 allows the first plate 240 and the side plate 250 of the cooling component 120 to be firmly bonded to the cell body 260 of at least one cell 110 using thermally conductive adhesive. That is, the thermally conductive adhesive can directly act between the cooling component 120 and the cell body 260, thereby enhancing the bonding strength and reducing the risk of loosening between the cooling component 120 and the cell 110 due to insufficient bonding strength of the insulating film 270.

[0036] To ensure the bonding strength between the first plate 240 of the cold plate and the first part 210 of the cell 110, it is necessary to ensure that the first window portion 280 and the first plate 240 have a sufficiently large relative area. Referring to Figures 2, 6, and 7, Figure 6 is a top view of the multiple cells 110 in Figure 2, and Figure 7 is an enlarged perspective view of part B in Figure 6. In some embodiments, when the distance d between the electrode post 230 and the side plate 250 of the cold plate is fixed in the first direction, the larger the dimension L3 of the first window portion 280 in the first direction, the larger the bonding area of ​​the thermally conductive adhesive between the first plate 240 and the cell body 260, resulting in higher heat conduction efficiency and bonding strength. However, if the dimension L3 of the first window portion 280 in the first direction is greater than the dimension L1 of the first plate 240 in the first direction, the first plate 240 will not be able to completely cover the first window portion 280, resulting in a portion of the first window portion 280 being exposed. Furthermore, the exposed portion of the battery cell 110 requires additional insulation measures to prevent short circuits. Therefore, to avoid the above problems, L3 must be less than L1 to ensure that the first plate 240 can cover the first window portion 280.

[0037] Based on the above considerations, in some embodiments, while the ratio of L1 to d should be in the range of 0.8 to 1, the ratio of the dimension L3 of the first window portion 280 in the first direction to d is set between 0.6 and 0.8. This ratio range ensures that the relative area between the first window portion 280 and the first plate 240 is sufficient, and also ensures that the size of the window portion is within a suitable range. That is, it can ensure the bonding strength between the first plate 240 and the first portion 210 while reducing the risk of short circuit in the cell 110.

[0038] It is easy to understand, as can be seen from Figures 2, 6, and 7, that if the dimension W1 of the first window portion 280 in the second direction is too small, the contact area between the first plate 240 and the cell body 260 may be insufficient, resulting in a relatively small area between them. This leads to poor adhesion strength, making the cooling component 120 of the cell assembly 100 prone to detachment during use, thus affecting the heat dissipation efficiency of the cell assembly 100 and potentially causing safety hazards. Conversely, if the dimension W1 of the first window portion 280 in the second direction is too large, the dimension of the insulating film 270 in the second direction will be relatively small, making the insulating film 270 prone to warping, detachment, or damage, thereby affecting the safety of the cell assembly 100 and increasing the risk of short circuits.

[0039] To address the aforementioned issues, in some embodiments, the ratio between the dimension W1 of the first window portion 280 in the second direction and the dimension W of the battery cell 110 in the second direction is set within the range of 0.5 to 0.8. Experimental verification has shown that when the ratio of W1 to W is controlled within this range, it ensures sufficient bonding area and bonding strength between the first plate 240 and the battery cell 110, while also effectively preventing the insulating film 270 from lifting or falling off, thereby ensuring the safety of the battery cell assembly 100.

[0040] In some embodiments, the ratio between the dimension L3 of the first window portion 280 in the first direction and the dimension L1 of the first plate 240 in the first direction is set in the range of 0.6 to 1. On the one hand, setting the ratio of L3 to L1 to no more than 1 ensures that the first window portion 280 does not exceed the length of the first plate 240 in the first direction, that is, the first plate 240 can completely cover the first window portion 280 in the first direction, so as to avoid the exposure of part of the first window portion 280, which could lead to a short circuit in the cell 110. On the other hand, setting the ratio of L3 to L1 to no less than 0.6 ensures that the relative area between the first plate 240 and the cell body 260 is large, so that the two have a strong adhesive strength.

[0041] In some embodiments, reference can be made to Figures 2 and 8, where Figure 8 is a side view of the plurality of cells 110 in Figure 2, and the ratio between the dimension L4 of the second window portion 290 in the height direction of the cell 110 and the height h of the cell 110 is set in the range of 0.5 to 0.6.

[0042] Experiments have shown that, on the one hand, if the ratio of L4 to h is less than 0.5, the relatively small area between the side plate 250 and the second window 290 may result in insufficient adhesion between the side plate 250 and the cell body 260 through the second window 290, leading to a higher risk of unstable cooling plate connection during the use of the cell assembly 100. On the other hand, setting the ratio of L4 to h to less than 0.6 ensures that the side plate 250 can completely cover the second window 290 in the second direction, thus preventing partial exposure of the second window 290 and potential short circuits in the cell 110.

[0043] In some embodiments, referring to Figures 2 and 8, the ratio of the dimension W2 of the second window portion 290 in the second direction to the width W of the cell 110 is set in the range of 0.5 to 0.7. On the one hand, when the ratio of W2 to W is greater than 0.5, it can ensure that the relative area between the side plate 250 and the second window portion 290 is large, so that the side plate 250 is bonded to the cell body 260 through the second window portion 290 with high strength, and the risk of unstable connection between the cooling element 120 and the cell assembly 100 during daily use of the cell assembly 100 is small. On the other hand, when the ratio of W2 to W is less than 0.7, it can ensure that the dimension of the insulating film 270 in the second direction is small, so that the insulating film 270 is not prone to warping, falling off or being damaged, thereby reducing the risk of short circuit in the cell assembly 100 and ensuring the safety of the cell assembly 100.

[0044] This application provides a battery cell assembly 100, which includes at least one battery cell 110 and a cooling component 120. Each battery cell 110 has a first portion 210 with a terminal post 230 and a side portion 220 connected to one side of the first portion 210. The cooling component 120 is used to cool at least one battery cell 110 and includes a first plate 240 and a side plate 250 connected to one side of the first plate 240. The first plate 240 abuts against the first portion 210 of at least one battery cell 110, and the side plate 250 abuts against the side portion 220 of at least one battery cell 110. The battery cell assembly 100 provided by this application, by thermally connecting the first plate 240 and the side plate 250 to the first portion 210 and the side portion 220 of the battery cell 110 respectively, enables the cooling plate to cool the high-temperature parts of the battery cell assembly 100 in fast charging mode, thereby effectively reducing the risk of local overheating of the battery cell assembly 100.

[0045] This application also provides a battery pack that includes the aforementioned cell assembly 100 and has all the advantages of the aforementioned cell assembly 100, which will not be repeated here.

[0046] This application also provides an electrical device, which may be, but is not limited to, pure electric and hybrid vehicles, etc. The electrical device includes a battery pack, which has all the advantages of a battery pack, which will not be elaborated here.

Claims

1. A cell pack comprising: at least one battery cell, each of the battery cells having a first portion and a side portion connected to one side of the first portion, each of the battery cells comprising a pole provided on the first portion; and a cooling member for cooling the at least one battery cell, the cooling member comprising a first plate and a side plate connected to one side of the first plate; wherein the first plate abuts against the first portion of the at least one battery cell, and the side plate abuts against the side portion of the at least one battery cell.

2. The cell pack of claim 1, wherein, 0.8≤L1 / d≤1; wherein L1 is a dimension of the first plate in a first direction, d is a distance between the pole and the side plate in the first direction, and the first direction is a direction in which the first plate points to the pole.

3. The cell pack of claim 2, wherein, 0.55≤L2 / h≤0.65; wherein h is a height of the at least one battery cell, and L2 is a dimension of the side plate in a height direction of the at least one battery cell.

4. The cell pack of any of claims 1-3, wherein, Each of the battery cells comprises a battery cell body and an insulating film covering an outer surface of the battery cell body, the insulating film being provided with a first windowing portion and a second windowing portion; wherein the first plate abuts against the battery cell body through the first windowing portion to abut against the first portion of the at least one battery cell, and the side plate abuts against the battery cell body through the second windowing portion to abut against the side portion of the at least one battery cell.

5. The cell pack of claim 4, wherein, 0.8≤L1 / d≤1, 0.6≤L3 / d≤0.8; wherein L1 is a dimension of the first plate in a first direction, L3 is a dimension of the first windowing portion in the first direction, d is a distance between the pole and the side plate in the first direction, and the first direction is a direction in which the first plate points to the pole.

6. The cell pack of claim 5, wherein, 0.5≤W1 / W≤0.8; wherein W is a dimension of the battery cell in a second direction, W1 is a dimension of the first windowing portion in the second direction, and the second direction is an arrangement direction of the battery cells.

7. The cell pack of claim 4, wherein, 0.6≤L3 / L1≤1; wherein L1 is a dimension of the first plate in a first direction, and L3 is a dimension of the first windowing portion in the first direction.

8. The cell pack of claim 6, wherein, 0.55≤L2 / h≤0.65, 0.5≤L4 / h≤0.6; wherein L2 is a dimension of the side plate in a height direction of the at least one battery cell, h is a height of the at least one battery cell, and L4 is a dimension of the second windowing portion in the height direction of the at least one battery cell.

9. The cell pack of claim 8, wherein, 0.5≤W2 / W≤0.7; wherein W is a width of the battery cell, and W2 is a dimension of the second windowing portion in the second direction.

10. A battery pack comprising the battery cell group of any one of claims 1-9.

11. An electrical device comprising the battery pack of claim 10.

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