Cover plate assembly, battery cell, battery pack and vehicle

Abstract

The utility model relates to a cover plate assembly, a battery cell, a battery pack and a vehicle, and the cover plate assembly comprises a pole and a cover plate; a protruding part is arranged on the lower surface of the cover plate, a groove corresponding to the protruding part is formed in the upper surface of the cover plate, and a through hole is formed in the bottom wall of the groove; the pole penetrates through the through hole and is fixed with the cover plate, the bottom end of the pole is located below the protruding part and forms a connecting end, the top end of the pole penetrates through the groove, and an insulating part is clamped between the pole and the cover plate. Through the arrangement of the cover plate assembly, the utilization rate of the height space of the battery cell can be improved, and the liquid retention capacity in the battery cell is improved, so that the service life of the battery pack is prolonged.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of battery packs, in particular to a cover plate assembly, a battery cell, a battery pack and a vehicle. BACKGROUND

[0002] Current lithium ion batteries have higher and higher requirements for energy density and long life indicators. From the perspective of materials, it is very limited to optimize and improve the specific capacity, so it is necessary to improve the space utilization rate in the battery cell as much as possible to install more active materials. At the same time, long cycle requires sufficient liquid retention to supplement the consumption of electrolyte in the long-term use process.

[0003] In order to improve the space utilization rate of the internal height of the battery cell, the internal space is compressed as much as possible in the design, such as the tab bending gap. It is easy to cause the risk of reverse insertion due to insufficient tab bending space, and in severe cases, it can cause internal short circuit and safety problems. Another way is to use high-density materials to improve the group margin and increase the space utilization rate in the thickness direction, which can also improve the energy density of the battery cell. However, this approach can result in too small residual space in the battery cell, and the liquid retention of the battery cell is insufficient, which is difficult to support the long cycle life.

[0004] Therefore, how to effectively improve the liquid retention in the battery cell in order to prolong the service life of the battery pack is a technical problem that needs to be solved by those skilled in the art. CONTENT OF THE INVENTION

[0005] The purpose of the application is to provide a cover plate assembly, a battery cell, a battery pack and a vehicle, which can improve the utilization rate of the height space of the battery cell, improve the liquid retention in the battery cell, and prolong the service life of the battery pack.

[0006] To solve the above technical problems, the application provides a cover plate assembly, which comprises a pole and a cover plate. The lower surface of the cover plate is provided with a protruding part, and the upper surface of the cover plate is provided with a groove corresponding to the protruding part. The groove bottom wall is provided with a through hole. The pole passes through the through hole and is fixed with the cover plate. The bottom end of the pole is located below the protruding part and forms a connecting end. The top end of the pole passes through the groove. An insulating piece is further arranged between the pole and the cover plate.

[0007] Optionally, the height of the top end of the pole protruding from the upper end surface of the cover plate is less than or equal to 3mm.

[0008] Optionally, the insulating piece comprises a lower plastic arranged on the lower surface of the cover plate. The spacing between the lower surface of the lower plastic and the lower surface of the pole is in the range of 2mm-8mm.

[0009] Optionally, the pole post includes a first part and a second part. The first part is disposed in the groove and abuts against the bottom wall of the groove. The second part includes a disc and a rod. One axial end of the rod is fixed to the middle of one side of the large surface of the disc. The disc abuts against the bottom of the cover plate. The rod passes through the perforation and is fixed to the first part.

[0010] Optionally, the top of the rod is provided with an inverted trapezoidal structure, the long bottom of the inverted trapezoidal structure is located on the side away from the disc, and the rod passes through the first part and is riveted and fixed to the upper end face of the first part.

[0011] This application also provides a battery cell, including a connector and a cover plate assembly as described above, wherein the connecting end of the terminal of the cover plate assembly is electrically connected to the connector.

[0012] Optionally, along the width direction of the cover plate, the connector extends outward relative to the pole post, and the distance between the outer edge of the connector and the outer edge of the pole post is greater than or equal to 3 mm.

[0013] Optionally, the device also includes a housing, wherein the cover plate assembly covers the top opening of the housing and encloses a closed installation space, wherein the protrusion of the cover plate assembly and the connector are both located within the installation space, and the minimum distance between the outer edge of the connector and the inner wall of the housing is greater than or equal to 5 mm along the width direction of the cover plate.

[0014] This application also provides a battery pack including the cells described above.

[0015] This application also provides a vehicle including the battery pack described above.

[0016] The cover plate assembly, battery cell, battery pack, and vehicle provided in this application have the following technical advantages compared to the prior art:

[0017] In the installed state, the cover assembly covers the top of the housing, and the protrusion of the cover protrudes downward and is located inside the housing of the cell. Since the connection end of the terminal is located below the protrusion, the terminal is at least partially located in the groove. Compared with the existing technology where the cover does not have a groove and the terminal is fixed to the cover and protrudes from the upper end face of the cover, this increases the length of the terminal extending into the housing. In other words, the overlap length between the terminal and the housing in the height direction is increased. With the overall height of the cell remaining unchanged, from the cross-sectional view of the cell, the top of the cell housing extends upward, that is, the height of the housing increases, the volume of the housing increases, the space inside the housing (i.e., the installation space) increases, and the space for storing electrolyte increases, which is conducive to increasing the electrolyte retention. During long-term use, it can effectively replenish the consumption of electrolyte and facilitate the extension of the battery pack's service life.

[0018] The electrode assembly is connected to the connector via a tab. Specifically, the tab connects to the upper surface of the connector, meaning it has a bent structure and connects to the side of the connector facing the pole post (this connection can be achieved by welding). The bent structure utilizes the space on both sides of the pole post, reducing the gap between the electrode assembly and the connector, improving the space utilization of the electrode assembly in the height direction, thereby increasing energy density. It also prevents the risk of inverted insertion due to insufficient space when the tab is bent. Furthermore, the increased internal space of the housing also increases the space between the connector and the cover plate, facilitating the connection operation between the tab and the connector. Attached Figure Description

[0019] Figure 1 This is a top view of the battery cell provided in the embodiments of this application;

[0020] Figure 2 yes Figure 1 Sectional view of AA;

[0021] Figure 3 yes Figure 1 BB section view;

[0022] Figure 4 yes Figure 3 Enlarged view of C;

[0023] Figure 5 yes Figure 4 Cross-sectional view of the middle cover plate assembly;

[0024] Figure 6 This is a cross-sectional view of the cover plate.

[0025] Appendix Figures 1-6 The reference numerals in the attached figures are explained as follows:

[0026] 10 Cover plate assembly; 20 Connector; 30 Housing; 40 Pole group; 50 Pole tab;

[0027] 1. Cover plate, 11. Protrusion, 12. Groove, 13. Perforation;

[0028] 2 pole posts, 21 first part, 22 second part, 23 connecting end;

[0029] 3. Plastic on top;

[0030] 4. Plastic parts;

[0031] 5. Insulating sealing gasket;

[0032] 6. Explosion-proof valve. Detailed Implementation

[0033] To enable those skilled in the art to better understand the technical solutions of this application, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] This application provides a cover plate assembly, a battery cell, a battery pack, and a vehicle. The vehicle includes a battery pack, which comprises a housing and multiple battery cells disposed within the housing. Figures 1-4 As shown, the battery cell includes a housing 30, an electrode assembly 40, a connector 20, and a cover assembly 10. The top of the housing 30 is open, and the cover assembly 10 covers the top of the housing 30, forming a closed installation space. The electrode assembly 40 and the connector 20 are both located inside the housing 30. The electrode assembly 40 consists of positive and negative electrode plates and a separator, and is usually of the wound or stacked type. The terminal posts 2 of the cover assembly 10 are electrically connected to the electrode assembly 40 through the connector 20. The installation space is also filled with electrolyte. The battery cell consumes electrolyte during normal operation. Therefore, the more electrolyte in the installation space (i.e., the more electrolyte it retains), the longer the battery pack's lifespan will be.

[0035] like Figure 5 and Figure 6 As shown, the cover plate assembly 10 provided in this embodiment includes a cover plate 1 and a pole post 2. The lower surface of the cover plate 1 is provided with a protrusion 11, which is set downward. The upper surface of the cover plate 1 is provided with a groove 12, which is corresponding to the protrusion 11. It is equivalent to the cover plate 1 being partially protruding downward to achieve structural thickening at this point, and the groove 12 is provided at this thickened point. The protrusion 11 can increase the depth of the groove 12. The bottom wall of the groove 12 is provided with a through hole 13. The pole post 2 passes through the through hole 13 and is fixed to the cover plate 1. The bottom end of the pole post 2 is located below the protrusion 11 and forms a connecting end 23. The connecting end 23 is used for electrical connection with the connector 20. The top end of the pole post 2 passes through the groove 12 and is used for connection with external connecting components such as busbars. An insulating component is also sandwiched between the pole post 2 and the cover plate 1 to achieve insulation.

[0036] In the installation state, such as Figure 4As shown, the cover plate assembly 10 covers the top of the housing 30. The protrusion 11 of the cover plate 1 protrudes downward and is located inside the housing 30 of the cell. Since the connection end 23 of the pole post 2 is located below the protrusion 11, the pole post 2 is at least partially located in the groove 12. Compared with the prior art structure in which the cover plate 1 does not have a groove 12 and the pole post 2 is fixed to the cover plate 1 and protrudes from the upper end face of the cover plate 1, this structure can increase the length of the pole post 2 extending into the housing 30. That is to say, the overlap length of the pole post 2 and the housing 30 in the height direction is increased. With the overall height of the cell remaining unchanged, from the cross-sectional view of the cell, the top of the housing 30 of the cell extends upward, that is, the height of the housing 30 increases, the volume of the housing 30 increases, the space inside the housing 30 (i.e., the installation space) increases, and the space for storing electrolyte increases, which is conducive to increasing the electrolyte retention. During long-term use, it can effectively replenish the consumption of electrolyte and facilitate the extension of the battery pack's service life.

[0037] like Figure 4 As shown, the electrode assembly 40 is connected to the connector 20 via an electrode tab 50. Specifically, the electrode tab 50 is connected to the upper end face of the connector 20, meaning it has a bent structure and connects to the side of the connector 20 facing the pole post 2 (this can be achieved through welding). The bent structure utilizes the space on both sides of the pole post 2, reducing the gap between the electrode assembly 40 and the connector 20, improving the space utilization rate of the electrode assembly 40 in the height direction, thereby increasing energy density. It also prevents the risk of the electrode tab 50 being inserted backwards due to insufficient space during bending. Furthermore, the increased internal space of the housing 30 also increases the space between the connector 20 and the cover plate 1, facilitating the connection operation between the electrode tab 50 and the connector 20.

[0038] The cover plate 1 is made of aluminum sheet, which is lightweight, high-strength, and easy to process. The cover plate 1 has two grooves 12 and two corresponding terminals 2, which are the positive terminal 2 and the negative terminal 2, respectively. An upper plastic 3 is sandwiched between the terminal 2 and the sidewall of the groove 12. The height of the top of the terminal 2 is greater than or equal to the height of the top of the upper plastic 3 and greater than or equal to the height of the upper surface of the cover plate 1, so as to ensure good insulation and facilitate the welding connection of the top of the terminal 2 to the busbar in the battery pack.

[0039] like Figure 1 As shown, the cover plate assembly 10 also includes an explosion-proof valve 6 and a liquid injection hole (not shown in the figure) disposed on the cover plate 1. The explosion-proof valve 6 is located between the two poles 2. When thermal runaway occurs in the cell, the pressure inside the housing 30 increases, the explosion-proof valve 6 ruptures, and high-temperature substances are ejected outward from the explosion-proof valve 6 to relieve pressure.

[0040] like Figure 5 and Figure 6As shown, the cover plate assembly 10 includes an upper plastic 3, a lower plastic 4, and an insulating sealing gasket 5. The upper plastic 3, the lower plastic 4, and the insulating sealing gasket 5 form the aforementioned insulating component. The upper plastic 3 is disposed between the inner wall surface of the groove 12 and the outer wall surface of the pole post 2, and the lower plastic 4 is disposed on the lower surface of the cover plate 1. Specifically, it also includes the lower surface of the protrusion 11. The inner wall surface of the perforation 13 is also provided with a sealing insulating gasket. Through the arrangement of the upper plastic 3, the lower plastic 4, and the sealing insulating gasket, the insulation between the pole post 2 and the cover plate 1 can be effectively guaranteed.

[0041] like Figure 2 As shown, the lower surface of the lower plastic 4 is also provided with a plurality of downwardly oriented protrusions 41 along the circumferential direction. In the installed state, the protrusions 41 can abut against the top of the electrode assembly 40 and limit the electrode assembly 40 located in the housing 30, preventing the electrode assembly 40 from shaking or displacing along the height direction and ensuring the stability of the electrode assembly 40. Specifically, the number and position of the protrusions 41 are not limited, but they are preferably set at both ends of the cover plate 1 along the length direction and near the liquid injection hole in the middle of the cover plate 1.

[0042] like Figure 4 As shown, the distance H1 between the lower surface of the lower plastic 4 and the lower end face of the pole post 2 is in the range of 2mm-8mm. The lower surface of the lower plastic 4 refers to the lower surface without the protrusion 41, and the lower end face of the pole post 2 refers to the lower end face of the connecting end 23. The distance H1 can be 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, etc. Compared with the scheme of setting the distance H1 to less than 2mm or greater than 8mm, the distance H1 in the range of 2mm-8mm can ensure the convenience of connecting the pole post 2 to the outside and the space utilization rate of the housing 30 in the height direction.

[0043] The top of the electrode post 2 can be aligned with the upper surface of the cover plate 1, or it can protrude from the upper surface of the cover plate 1 to facilitate connection between the electrode post 2 and the outside. Specifically, the height difference between the top of the electrode post 2 and the upper surface of the cover plate 1 is within the range of 0-3mm. That is, the height of the top of the electrode post 2 protruding from the upper surface of the cover plate 1 is less than or equal to 3mm, such as 0, 1mm, 2mm, 3mm, etc. When the height of the top of the electrode post 2 protruding from the upper surface of the cover plate 1 is 0, it means that the top of the electrode post 2 is aligned with the upper surface of the cover plate 1 and does not protrude from the upper surface of the cover plate 1. Of course, this height difference can also be set to 4mm, 5mm, etc. When the height of the top of the electrode post 2 protruding from the upper surface of the cover plate 1 is less than or equal to 3mm, the space of the cell in the height direction can be utilized as much as possible to increase the volume inside the housing 30 and increase the liquid retention capacity.

[0044] In the installed state, along the width direction of the cover plate 1 (i.e., along the thickness direction of the housing 30), the connector 20 extends outward relative to the pole post 2, and, as...Figure 4 As shown, along the width direction of the cover plate 1, the distance D1 between the outer edge of the connector 20 and the outer edge of the pole post 2 is greater than or equal to 3mm. Specifically, it can be 3mm, 4mm, 5mm, 6mm, etc. Compared with the scheme of setting the distance D1 to 1mm, 2mm, etc., which is less than 3mm, the distance D1 being greater than or equal to 3mm is more conducive to the bending setting of the pole tab 50, meets the welding area requirements of the pole tab 50 and the connector 20, and ensures welding stability.

[0045] like Figure 4 As shown, along the width direction of the cover plate 1, the minimum distance D2 between the outer edge of the connector 20 and the inner wall of the housing 30 is greater than or equal to 5mm. Specifically, it can be 5mm, 6mm, 7mm, 8mm, etc. Compared with the scheme of setting the minimum distance D2 to 3mm, 4mm, etc., which is less than 5mm, the minimum distance D2 being greater than or equal to 5mm can provide more space for the bending structure of the tab 50, and prevent the risk of inverted insertion due to insufficient space when the tab 50 is bent.

[0046] In this embodiment, as Figure 5 As shown, the pole post 2 includes two parts: a first part 21 and a second part 22. The first part 21 is located in the groove 12. The bottom of the first part 21 is blocked from passing through the through hole 13 by abutting against the bottom of the groove 12, thus restricting the pole post 2 from moving downward relative to the cover plate 1. The second part 22 includes a disc and a rod. One axial end of the rod is fixed to the middle of the large surface of the disc. The cross-section of the second part 22 is T-shaped. The disc is located at the bottom of the cover plate 1, specifically at the bottom of the protrusion 11 and forms a connecting end 23 to restrict the pole post 2 from moving upward relative to the cover plate 1. The rod passes through the through hole 13 and is fixed to the first part 21. The first part 21 and the second part 22 are fixed together and can be fixed to the cover plate 1 by clamping the bottom wall of the groove 12.

[0047] In other words, the first part 21 is located in the groove 12, and the top surface of the first part 21 can be aligned with or protrude from the upper end surface of the cover plate 1. The disc portion of the second part 22 is located below the protrusion 11 and forms a connecting end 23 for welding to the connector 20. Due to its large area, the disc portion cannot pass through the through hole 13 and abuts against the bottom of the protrusion 11. The rod portion of the second part 22 can pass through the through hole 13 and be fixed to the first part 21. This arrangement ensures the installation stability between the pole post 2 and the cover plate 1, while also facilitating installation operations.

[0048] The first part 21 is also provided with a riveting hole. The rod passes through the through hole 13 and the riveting hole of the first part 21 and is riveted and fixed to the upper end face of the first part 21. During installation, the first part 21 is placed in the groove 12, and the rod of the second part 22 is pushed out from the bottom of the cover plate 1 upward. After the rod passes through the first part 21, the disc abuts against the lower surface of the protrusion 11. The top end face of the rod is riveted and fixed to the top surface of the first part 21, thus realizing the installation operation of the pole post 2 and the cover plate 1.

[0049] The structure of pole 2 can be as follows: Figure 5 As shown, the cross-section of the first part 21 is also T-shaped, with its disc portion located in the groove 12 and abutting against the bottom wall of the groove 12. The rod portion of the first part 21 is located inside the through hole 13. Alternatively, the first part 21 can be set as an annular structure, which is set in the groove 12 and abutting against the bottom wall of the groove 12. The rod portion of the second part 22 passes through the through hole 13 and fits against the inner peripheral wall of the through hole 13.

[0050] Specifically, such as Figure 5 As shown, the rod portion of the second part 22 also has an inverted trapezoidal structure, that is, the long bottom of the trapezoidal structure is located on the side away from the top of the disc, which facilitates fixing it to the first part 21 by riveting. Of course, in this embodiment, the specific structure of the rod portion of the second part 22 is not limited. For example, the top edge of the rod portion can also be provided with an extension edge extending upward in the circumferential direction. During installation, it can be fixed to the first part 21 by riveting through the extension edge. However, fixing it to the first part 21 by riveting through the long bottom of the inverted trapezoidal structure can further ensure the stability of the riveting.

[0051] In this embodiment, the materials of the first part 21 and the second part 22 are not limited and can be the same or different. The second part 22 is preferably made of copper. The bottom of the second part 22 forms a connecting end 23, which is connected to the electrode group 40 through the connector 20. The top of the second part 22 is used to connect to the external busbar. When the second part 22 is made of copper, it has good conductivity. The first part 21 can be made of aluminum, which has good heat dissipation and ensures the stability of the battery cell in use.

[0052] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, 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.

[0053] 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.

[0054] The above are merely preferred embodiments of this application. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A cover assembly, characterized by The cover plate (1) is provided with a protrusion (11) on the lower surface, and a groove (12) corresponding to the protrusion (11) on the upper surface, and the groove (12) is provided with a through hole (13) on the groove bottom wall. The pole column (2) passes through the through hole (13) and is fixed with the cover plate (1), the bottom end of the pole column (2) is below the protrusion (11) and forms a connecting end (23), the top end of the pole column (2) passes through the groove (12), and an insulating piece is further arranged between the pole column (2) and the cover plate (1). The height of the top end of the pole column (2) protruding from the upper end surface of the cover plate (1) is less than or equal to 3mm.

2. The cover plate assembly of claim 1, wherein, The insulating piece includes a lower plastic (4) arranged on the lower surface of the cover plate (1), and the distance between the lower surface of the lower plastic (4) and the lower surface of the pole column (2) is within the range of 2mm-8mm.

3. The cover plate assembly of claim 1, wherein, The pole column (2) includes a first part (21) and a second part (22), the first part (21) is arranged in the groove (12) and abuts against the groove bottom wall of the groove (12), the second part (22) includes a disc part and a rod part, one end of the rod part is fixed with the middle position of one side large surface of the disc part, the disc part abuts against the bottom of the cover plate (1), and the rod part passes through the through hole (13) and is fixed with the first part (21).

4. The cover plate assembly of any one of claims 1-3, wherein, The top of the rod part is provided with an inverted trapezoidal structure, the long bottom of the inverted trapezoidal structure is arranged away from one side of the disc part, the rod part passes through the first part (21) and is riveted and fixed with the upper end surface of the first part (21).

5. The cover plate assembly of claim 4, wherein, The connecting piece (20) and the cover plate assembly according to any one of claims 1-5 are included, and the connecting end (23) of the pole column (2) of the cover plate assembly is electrically connected with the connecting piece (20).

6. An electric cell characterized by Along the width direction of the cover plate (1), the connecting piece (20) is arranged to extend outward compared with the pole column (2), and the distance between the outer edge of the connecting piece (20) and the outer edge of the pole column (2) is greater than or equal to 3mm.

7. The electric cell of claim 6, wherein, The housing (30) is further included, the cover plate assembly is covered on the top opening of the housing (30) and encloses to form a closed mounting space, the protrusion (11) of the cover plate assembly and the connecting piece (20) are located in the mounting space, and along the width direction of the cover plate (1), the minimum distance between the outer edge of the connecting piece (20) and the inner wall surface of the housing (30) is greater than or equal to 5mm.

8. The electric cell of claim 6, wherein, The electric core according to any one of claims 6-8 is included.

9. A battery pack, characterized by, The battery pack according to claim 9 is included.

10. A vehicle characterized by comprising: ​

Images