Battery cell and battery pack

Abstract

The utility model relates to the technical field of batteries, and discloses a battery cell and a battery pack, the battery cell comprises a shell, a cover plate, a connecting sheet, a pole group, a sealing plate and a pressure relief structure, compared with the prior art, the battery cell with the structure has the advantages that the extension height of the tabs back to the pole group is reduced, and the connecting pieces extend horizontally, so that the space occupied by the bending of the connecting pieces and the bending of the tabs in the shell can be effectively reduced, the space in the shell can be fully utilized to arrange the pole group, and the space utilization rate in the battery cell is further improved. And the sealing plate is hermetically arranged on the operation hole to form the sealing of the whole structure of the battery. Meanwhile, the pressure relief structure is arranged on the sealing plate, and the liquid injection hole is formed in the sealing plate, so that enough space left on the cover plate can be used for forming the operation hole, the size of the operation hole can be changed by the battery cell according to the required welding area of the tab and the connecting piece, and the electric connection area of the tab and the connecting piece is ensured; and the over-current capability of the battery cell is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, and particularly relates to a battery cell and a battery pack. Background Art

[0002] The battery cell includes structures such as a housing, a pole group and a cover plate. The pole group is arranged inside the housing. Pole tabs are arranged at the ends of the pole group. The cover plate is arranged on the opening of the housing. When assembling the battery cell, one side of the connecting piece is first welded to the bottom plate of the pole post. The other side of the connecting piece extends a certain distance into the housing and then bends to form a connecting portion. The pole tab extends a certain distance in the direction of the cover plate and then bends to form a bent portion. The connecting portion is welded to the bent portion to realize the electrical connection between the pole tab and the connecting piece. For the battery cell with such a structure, since the bending of the connecting piece and the pole tab occupies a certain space inside the housing, the space utilization rate inside the battery cell is low. Summary of the Utility Model

[0003] In view of this, the utility model provides a battery cell and a battery pack to solve the problem of low space utilization rate inside the battery cell in the prior art.

[0004] In a first aspect, the utility model provides a battery cell, comprising:

[0005] A housing with an open end on one side;

[0006] A cover plate arranged on the open end. Two pole post holes and an operation hole are arranged on the cover plate. The two pole post holes are located on both sides of the operation hole extending along a first direction. Pole posts are arranged in the pole post holes. The inner end face of the pole post is located inside the cover plate;

[0007] A connecting piece extending horizontally. The connecting piece includes a pole post connecting portion and a pole tab connecting portion. The pole post connecting portion is electrically connected to the inner end face of the pole post; One side of the pole tab connecting portion is connected to the pole post connecting portion, and the other side extends towards the side of the cover plate inside the operation hole;

[0008] A pole group arranged inside the housing; Pole tabs are arranged at the ends of the pole group. The pole tabs extend out of the operation hole and bend towards the outer wall surface of the pole tab connecting portion to form a bent portion. The bent portion is attached to the pole tab connecting portion and is electrically connected to the pole tab connecting portion;

[0009] A sealing plate hermetically arranged on the operation hole; A liquid injection hole is arranged on the sealing plate;

[0010] A pressure relief structure arranged on the sealing plate.

[0011] Beneficial effects: For the battery cell with this structure, the connecting piece extends horizontally and is electrically connected to the inner end face of the pole column; an operation hole is provided on the housing, the tab extends out of the housing through the operation hole, and then the tab is bent on the outer wall surface of the tab connecting part, and is electrically connected to the tab connecting part through the bent part of the tab, realizing the electrical connection between the tab and the connecting piece. The housing, the connecting piece and the pole column can be supplied with components during the procurement stage, that is, the connecting piece is directly connected to the pole column for supply. During the manufacturing process of the battery cell, the bending process of the connecting piece is omitted. After the tab is bent, it is attached to the outer wall surface of the tab connecting part. Compared with the prior art, the height of the tab extending away from the electrode group is reduced, and the connecting piece extends horizontally, which can effectively reduce the space occupied by the bending of the connecting piece and the bending of the tab inside the housing, and the space inside the housing can be fully utilized to arrange the electrode group, thereby improving the space utilization rate inside the battery cell. The sealing plate is hermetically arranged on the operation hole to form the seal of the overall battery structure.

[0012] For a battery with a certain capacity, the size specification of the pressure relief mechanism is fixed. If the pressure relief structure is arranged on the solid part of the cover plate, the pressure relief structure will occupy the opening space of the operation hole, resulting in limited opening of the operation hole. The tab needs to extend out of the cover plate through the operation hole and then be bent and welded to the connecting piece. The limited opening size of the operation hole will result in limited space for the tab to extend out of the cover plate and be bent, resulting in limited electrical connection area between the tab and the connecting piece, thus affecting the over-current capacity of the battery cell. To solve this problem, in the present utility model, by arranging the pressure relief structure on the sealing plate and arranging the liquid injection hole on the sealing plate at the same time, enough space can be left on the cover plate for opening the operation hole, so that the battery cell can change the size of the operation hole according to the required electrical connection area between the tab and the connecting piece, ensuring the electrical connection area between the tab and the connecting piece and improving the over-current capacity of the battery cell.

[0013] In an optional embodiment, the long side of the sealing plate extends in the first direction, the long side of the pressure relief structure extends in a second direction perpendicular to the first direction, the wide side of the sealing plate extends in the second direction, and the distance between the end of the long side of the pressure relief structure and the wide side of the sealing plate is greater than 2 mm.

[0014] Beneficial effects: Such an arrangement can keep a sufficient distance between the pressure relief structure and the edge of the sealing plate, avoiding the influence of the welding heat on the pressure relief structure when welding the sealing plate, thereby effectively ensuring the safety performance of the battery cell.

[0015] In an optional embodiment, the liquid injection hole and the pressure relief structure are arranged at intervals, and the distance between the liquid injection hole and the pressure relief structure is greater than 3.6 mm.

[0016] Beneficial effects: The area between the liquid injection hole and the pressure relief structure can be used for the operation of the cleaning tooling, avoiding interference with the cleaning tooling due to too small a distance between the two.

[0017] In an alternative embodiment, the distance between the liquid injection hole and the edge of the sealing plate is greater than 4 mm.

[0018] Beneficial effects: Such a setting can keep an appropriate distance between the liquid injection hole and the edge of the sealing plate, avoiding the influence of the opening on the strength of the sealing plate.

[0019] In an alternative embodiment, the pressure relief structure includes an explosion-proof valve. An installation hole is provided on the sealing plate, and the explosion-proof valve is arranged in the installation hole.

[0020] In an alternative embodiment, the installation hole is centrally arranged on the sealing plate.

[0021] Beneficial effects: Such a setting is beneficial to ensuring the overall strength of the sealing plate, thereby ensuring the sealing effect of the sealing plate and the overall strength of the battery cell.

[0022] In an alternative embodiment, the pole holes are arranged on both sides of the length direction of the operation hole. The wide edge of the operation hole extends in a second direction perpendicular to the first direction. The width of the cover plate is W, and the width of the operation hole is W1, where W1 ≤ 0.8W.

[0023] Beneficial effects: Such a setting can ensure that there is an entity cover plate with sufficient width on both sides of the operation hole, which can ensure the overall strength of the cover plate. The cover plate is welded to the housing, thereby ensuring the overall strength of the battery cell.

[0024] In an alternative embodiment, the operation hole is centrally arranged on the cover plate.

[0025] Beneficial effects: The operation hole is centrally arranged along both the length direction and the width direction of the cover plate, which can further ensure the structural strength of the cover plate.

[0026] In an alternative embodiment, there are two sets of pole groups, and the pole lugs at the ends of the two sets of pole groups are arranged oppositely; a groove is provided in the middle area of the pole lug connection part, and the bent parts of the two sets of pole lugs are respectively attached to the pole lug connection parts on both sides of the groove.

[0027] In a second aspect, the present invention also provides a battery pack, including the battery cell described in any one of the above. The battery pack includes the battery cell and has the same technical effects as the battery cell, which will not be elaborated here. Description of the Drawings

[0028] In order to more clearly illustrate the specific embodiments of the present utility model or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0029] Figure 1 Schematic three-dimensional structure diagram of a battery cell according to an embodiment of the present utility model;

[0030] Figure 2 For Figure 1 top view;

[0031] Figure 3 For Figure 2 cross-sectional view taken along line A-A in

[0032] Figure 4 Schematic diagram during the assembly process of the cover plate and the electrode group in a battery cell according to an embodiment of the present utility model;

[0033] Figure 5 Schematic diagram during the assembly process of the cover plate and the electrode group in a battery cell according to an embodiment of the present utility model;

[0034] Figure 6 Schematic diagram of the cooperation between the connecting piece and the tab in a battery cell according to an embodiment of the present utility model;

[0035] Figure 7 Schematic diagram of the cooperation between the connecting piece and the tab in a battery cell according to an embodiment of the present utility model;

[0036] Figure 8 Cross-sectional view of the cover plate assembly in a battery cell according to an embodiment of the present utility model;

[0037] Figure 9 Schematic three-dimensional structure diagram of the cover plate assembly in a battery cell according to an embodiment of the present utility model.

[0038] Explanation of reference numerals:

[0039] 1. Housing; 2. Cover plate; 201. Operation hole; 3. Connecting piece; 301. Terminal connection part; 302. Tab connection part; 303. Groove; 4. Electrode group; 5. Tab; 501. Bent part; 6. Sealing plate; 601. Liquid injection hole; 7. Pressure relief structure; 8. Positive terminal; 9. Negative terminal; 10. First insulating part; 11. Sealing part; 12. Second insulating part. Specific embodiments

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are some, but not all, of the embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0041] The following will describe the embodiments of the present utility model in conjunction with Figures 1 to 9 , the embodiments of the present utility model will be described.

[0042] According to an embodiment of the present utility model, on the one hand, a battery cell is provided, which includes a housing 1, a cover plate 2, a connecting piece 3, an electrode assembly 4, a sealing plate 6, and a pressure relief structure 7. Among them, one side of the housing 1 is provided with an open end; the cover plate 2 is arranged on the open end, and two pole holes and an operation hole 201 are provided on the cover plate 2. The two pole holes are located on both sides of the operation hole 201 extending along the first direction. A pole is provided in the pole hole, and the inner end surface of the pole is located inside the cover plate 2; the connecting piece 3 extends horizontally, and the connecting piece 3 includes a pole connecting portion 301 and an ear connecting portion 302. The pole connecting portion 301 is electrically connected to the inner end surface of the pole; one side of the ear connecting portion 302 is connected to the pole connecting portion 301, and the other side extends toward the side of the operation hole 201 facing the inside of the cover plate 2; the electrode assembly 4 is arranged inside the housing 1; an ear 5 is provided at the end of the electrode assembly 4. The ear 5 extends out of the operation hole 201 and is bent toward the outer wall surface of the ear connecting portion 302 to form a bent portion 501. The bent portion 501 is attached to the ear connecting portion 302 and is electrically connected to the ear connecting portion 302; the sealing plate 6 is hermetically arranged on the operation hole 201; a liquid injection hole 601 is provided on the sealing plate 6; the pressure relief structure 7 is arranged on the sealing plate 6.

[0043] For the battery cell with this structure, the connecting piece 3 extends horizontally and is electrically connected to the inner end surface of the pole; an operation hole 201 is provided on the housing 1, and the ear 5 extends out of the housing 1 through the operation hole 201, and then the ear 5 is bent toward the outer wall surface of the ear connecting portion 302, and the bent portion 501 of the ear 5 is electrically connected to the ear connecting portion 302 to realize the electrical connection between the ear 5 and the connecting piece 3. The housing 1, the connecting piece 3, and the pole can be selected for component supply during the procurement stage, that is, the connecting piece 3 is directly connected to the pole for supply. The bending process of the connecting piece 3 is omitted during the manufacturing process of the battery cell. After the ear 5 is bent, it is attached to the outer wall surface of the ear connecting portion 302. Compared with the prior art, the height of the ear 5 extending away from the electrode assembly 4 is reduced, and the connecting piece 3 extends horizontally, which can effectively reduce the space occupied by the bending of the connecting piece 3 and the bending of the ear 5 inside the housing 1, and the space inside the housing 1 can be fully utilized to arrange the electrode assembly 4, thereby improving the space utilization rate inside the battery cell. The sealing plate 6 is hermetically arranged on the operation hole 201 to form the seal of the overall battery structure.

[0044] For a battery with a certain capacity, the size specifications of the pressure relief mechanism are fixed. If the pressure relief structure 7 is arranged on the solid part of the cover plate 2, the pressure relief structure 7 will occupy the opening space of the operation hole 201, resulting in limited opening of the operation hole 201. The tab 5 needs to extend out of the cover plate 2 through the operation hole 201 and then be bent to be welded to the connecting piece 3. The limited opening size of the operation hole 201 will result in limited space for the tab 5 to extend out of the cover plate 2 and be bent, resulting in limited electrical connection area between the tab 5 and the connecting piece 3, thereby affecting the overcurrent capacity of the battery cell. To solve this problem, in the present utility model, by arranging the pressure relief structure 7 on the sealing plate 6 and simultaneously arranging the liquid injection hole 601 on the sealing plate 6, sufficient space can be left on the cover plate 2 for opening the operation hole 201, enabling the battery cell to change the size of the operation hole 201 according to the required welding area between the tab 5 and the connecting piece 3, ensuring the electrical connection area between the tab 5 and the connecting piece 3, and improving the overcurrent capacity of the battery cell.

[0045] As Figure 1 and Figure 2 shown, in some embodiments, the long side of the sealing plate 6 extends in the first direction (x direction), the long side of the pressure relief structure 7 extends in the second direction (y direction) perpendicular to the first direction, the wide side of the sealing plate 6 extends in the second direction (y direction), the distance between the end of the long side of the pressure relief structure 7 and the wide side of the sealing plate 6 is greater than 2 mm, and the distances from both ends in the width direction of the pressure relief structure 7 to the long side edge of the sealing plate 6 are greater than the distance between the end of the long side of the pressure relief structure 7 and the wide side of the sealing plate 6. The sealing plate 6 is welded to the cover plate 2. If the pressure relief mechanism is too close to the edge of the sealing plate 6, the welding heat will affect the pressure relief structure 7, thereby affecting the opening pressure of the pressure relief structure 7 and the safety performance of the battery cell. In the present utility model, the distance between the end of the long side of the pressure relief structure 7 and the wide side of the sealing plate 6 is greater than 2 mm. Such a setting can keep a sufficient distance between the pressure relief structure 7 and the edge of the sealing plate 6, avoiding the influence of the welding heat on the pressure relief structure 7 when welding the sealing plate 6, thereby effectively ensuring the safety performance of the battery cell.

[0046] As Figure 1 and Figure 2 shown, in some embodiments, the liquid injection hole 601 and the pressure relief structure 7 are arranged at intervals, and the distance between the liquid injection hole 601 and the pressure relief structure 7 is greater than 3.6 mm. After the battery cell is assembled, electrolyte is injected into the interior of the housing 1 through the liquid injection hole 601. After the injection is completed, there will be residual electrolyte on the outer wall surface of the sealing plate 6 in the area around the liquid injection hole 601, and a tooling is needed to clean the residual electrolyte. The distance between the liquid injection hole 601 and the pressure relief structure 7 is greater than 3.6 mm, and the area between the liquid injection hole 601 and the pressure relief structure 7 can be used for the operation of the cleaning tooling, avoiding interference with the cleaning tooling due to too small a distance between the two.

[0047] Optionally, in some embodiments, the distance between the liquid injection hole 601 and the edge of the sealing plate 6 is greater than 4 mm. Such a setting can keep an appropriate distance between the liquid injection hole 601 and the edge of the sealing plate 6, avoiding the influence of the opening on the strength of the sealing plate 6.

[0048] In some embodiments, the pressure relief structure 7 includes an explosion-proof valve. An installation hole is provided on the sealing plate 6, and the explosion-proof valve is arranged in the installation hole. The explosion-proof valve can control the pressure of the gas inside the battery cell, keeping the pressure inside the battery cell within a safe range, preventing the battery cell from exploding or catching fire due to excessive expansion, etc., and effectively ensuring the safety of the battery cell.

[0049] Optionally, in some embodiments, the battery cell includes a square shell battery cell. The length direction of the battery cell extends along the x direction, the width direction of the battery cell extends along the y direction, and the height direction of the battery cell extends along the z direction.

[0050] As Figure 2 shown, the installation hole is centrally arranged on the sealing plate 6, that is, the installation hole is centrally arranged in both the length direction and the width direction of the sealing plate 6. Such a setting is beneficial to ensuring the overall strength of the sealing plate 6, thereby ensuring the sealing effect of the sealing plate 6 and the overall strength of the battery cell.

[0051] As Figures 1 to 5 shown, in some embodiments, the cover plate 2 and the operation hole 201 are both rectangular. The pole hole is arranged on both sides of the operation hole 201 in the length direction (x direction). The wide edge of the operation hole 201 extends along the second direction (y direction) perpendicular to the first direction. The width of the cover plate 2 is W, and the width of the operation hole 201 is W1, and W1 ≤ 0.8W. Such a setting can ensure that there is an entity cover plate 2 with sufficient width on both sides of the operation hole 201, and can ensure the overall strength of the cover plate 2. The cover plate 2 is welded to the housing 1, thereby ensuring the overall strength of the battery cell.

[0052] Preferably, in some embodiments, the operation hole 201 is centrally arranged on the cover plate 2, that is, the operation hole 201 is centrally arranged along both the length direction and the width direction of the cover plate 2, which can further ensure the structural strength of the cover plate 2.

[0053] As Figures 4 to 7 shown, in some embodiments, there are two sets of pole groups 4, and the pole tabs 5 at the ends of the two sets of pole groups 4 are arranged oppositely; a groove 303 is provided in the middle area of the pole tab connecting part 302, and the bent parts 501 of the two sets of pole tabs 5 are respectively attached to the pole tab connecting part 302 on both sides of the groove 303. During the process of welding the bent part 501 and the pole tab connecting part 302, the bent parts 501 on both sides of the groove 303 are welded simultaneously. A positioning tooling is required during the welding process. The positioning tooling is positioned by identifying the position of the groove 303. The positioning tooling is inserted into the groove 303 to position the bent parts 501 on both sides of the groove 303 at the same time.

[0054] As Figure 6 and Figure 7 shown, two sets of electrode groups 4 are arranged in a fitting manner. At the top of each set of electrode groups 4, a positive electrode tab 5 and a negative electrode tab 5 are arranged at intervals along the first direction (x direction). The positive electrode tabs 5 of the two sets of electrode groups 4 are opposite and arranged at intervals, and the negative electrode tabs 5 of the two sets of electrode groups 4 are opposite and arranged at intervals. When the battery cell assembly comes in for processing, the connecting piece 3 is welded and fixed on the pole column. During the battery cell assembly process, the electrode group 4 is placed into the housing 1, and the tab connecting part 302 is located between the two sets of opposite tabs 5. The tab 5 extends out of the housing 1 through the operation hole 201, and the tab 5 is bent through the operation hole 201 to form a bent part 501, and then the bent part 501 is welded on the tab connecting part 302 through the operation hole 201.

[0055] The pole column includes a positive pole column 8 and a negative pole column 9, and the positive pole column 8 and the negative pole column 9 are respectively arranged in the pole column holes on both sides of the operation hole 201. Correspondingly, the connecting piece 3 includes a positive connecting piece and a negative connecting piece. The pole column connecting part 301 of the positive connecting piece is welded to the positive pole column 8, the tab connecting part 302 of the positive connecting piece is welded to the positive electrode tab 5, the pole column connecting part 301 of the negative connecting piece is welded to the negative pole column 9, and the tab connecting part 302 of the negative connecting piece is welded to the negative electrode tab 5. The structure of the positive connecting piece is the same as that of the negative connecting piece 3.

[0056] As Figure 3 shown, the battery cell further includes a first insulating member 10, a sealing member 11, and a second insulating member 12. The first insulating member 10 is arranged between the outer wall surface of the side cover plate 2 of the pole column hole and the pole column, the sealing member 11 is arranged between the pole column and the cover plate 2, and the second insulating member 12 is arranged on the inner wall surface of the cover plate 2.

[0057] According to an embodiment of the present invention, on the other hand, a battery pack is further provided, which includes the above-mentioned battery cell.

[0058] For the battery cell with this structure, the space occupied by the bending of the connecting piece 3 and the tab 5 inside the housing 1 can be effectively reduced, and the space inside the housing 1 can be fully utilized to arrange the electrode group 4, thereby improving the space utilization rate inside the battery cell. The sealing plate 6 is hermetically arranged on the operation hole 201 to form the seal of the overall battery structure. And by arranging the pressure relief structure 7 on the sealing plate 6 and simultaneously arranging the liquid injection hole 601 on the sealing plate 6 for the battery cell, enough space can be left on the cover plate 2 for opening the operation hole 201, so that the battery cell can change the size of the operation hole 201 according to the required welding area between the tab 5 and the connecting piece 3, ensuring the electrical connection area between the tab 5 and the connecting piece 3 and improving the overcurrent capacity of the battery cell.

[0059] Although embodiments of the present utility model have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present utility model, and such modifications and variations fall within the scope defined by the appended claims.

Claims

1. A battery cell, characterized in that, Comprising: A housing with an open end on one side; A cover plate provided on the open end, with two pole holes and an operation hole provided on the cover plate. The two pole holes are located on both sides of the operation hole extending in a first direction. A pole is provided in each pole hole, and the inner end surface of the pole is located inside the cover plate; A connecting piece extending horizontally. The connecting piece includes a pole connecting portion and an ear connecting portion. The pole connecting portion is electrically connected to the inner end surface of the pole; one side of the ear connecting portion is connected to the pole connecting portion, and the other side extends towards the side of the operation hole facing the inside of the cover plate; A pole group provided inside the housing; an ear is provided at the end of the pole group. The ear extends out of the operation hole and is bent towards the outer wall surface of the ear connecting portion to form a bent portion. The bent portion is attached to the ear connecting portion and is electrically connected to the ear connecting portion; A sealing plate hermetically provided on the operation hole; a liquid injection hole is provided on the sealing plate; A pressure relief structure provided on the sealing plate.

2. The battery cell according to claim 1, wherein, The long side of the sealing plate extends in the first direction, the long side of the pressure relief structure extends in a second direction perpendicular to the first direction, the wide side of the sealing plate extends in the second direction, and the distance between the end of the long side of the pressure relief structure and the wide side of the sealing plate is greater than 2 mm.

3. The battery cell according to claim 1 or 2, characterized in that, The liquid injection hole and the pressure relief structure are arranged at intervals, and the distance between the liquid injection hole and the pressure relief structure is greater than 3.6 mm.

4. The battery cell according to claim 1 or 2, characterized in that, The distance between the liquid injection hole and the edge of the sealing plate is greater than 4 mm.

5. The cell according to claim 1 or 2, characterized in that, The pressure relief structure includes an explosion-proof valve. An installation hole is provided on the sealing plate, and the explosion-proof valve is provided in the installation hole.

6. The battery cell according to claim 5, characterized in that, The installation hole is centrally arranged on the sealing plate.

7. The battery cell according to claim 1 or 2, characterized in that, The pole holes are provided on both sides of the operation hole in the length direction of the operation hole. The wide side of the operation hole extends in a second direction perpendicular to the first direction. The width of the cover plate is W, and the width of the operation hole is W1, where W1 ≤ 0.8W.

8. The battery cell according to claim 7, wherein, The operation hole is centrally arranged on the cover plate.

9. The battery cell according to claim 1 or 2, characterized in that, There are two sets of the pole groups, and the ears at the ends of the two sets of pole groups are arranged oppositely; a groove is provided in the middle area of the ear connecting portion, and the bent portions of the ears of the two sets are respectively attached to the ear connecting portions on both sides of the groove.

10. A battery pack, characterized in that, Including the battery cell according to any one of claims 1 to 9.

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