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, and the battery cell mainly comprises a shell, a cover plate, a pair of connecting sheets, a sealing plate and an insulating plate, a plurality of pole groups and a plurality of pairs of tabs corresponding to the pole groups are arranged in the shell; a through hole and a pair of poles are arranged on the cover plate, and the through hole is positioned between the pair of poles; one end of the connecting sheet is connected with the pole, and the other end extends to the through hole and is connected with the tab; a first liquid injection hole is formed in the sealing plate, a second liquid injection hole communicated with the first liquid injection hole is formed in the insulating plate, a convex part is formed on the peripheral wall of the lower end of the second liquid injection hole, at least one first groove is formed in the lower end of the convex part, and the first groove is communicated with the second liquid injection hole. According to the utility model, the connecting piece and the tab are arranged in the through hole, the space utilization rate is improved, the first groove is formed in the lower end of the second liquid injection hole, when the second liquid injection hole is blocked, the electrolyte can be continuously injected through the first groove, and the reliability of the liquid injection process is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to an electric core and a battery pack. Background Art

[0002] With the development of new energy technologies, battery packs are increasingly used in various new energy products. In a battery pack, a pole column is connected to an ear of an electric core through a connecting piece to achieve electrical conduction.

[0003] However, both the connecting piece and the ear need to be bent, and the connecting piece, the pole column and the ear are usually located on the same vertical plane, so a relatively large thickness space needs to be occupied, resulting in low space utilization rate of the electric core. Summary of the Utility Model

[0004] In view of this, the utility model provides an electric core and a battery pack to solve the problem that the existing connecting piece connecting the pole column and the ear needs to occupy a relatively large thickness space, resulting in low space utilization rate of the electric core.

[0005] In a first aspect, the utility model provides an electric core, comprising:

[0006] A housing, provided with an opening, a plurality of pole groups arranged in the opening, and a plurality of pairs of ears corresponding to the pole groups one by one;

[0007] A cover plate, covering the opening, the cover plate being provided with a through hole and a pair of pole columns, the through hole being located between the pair of pole columns;

[0008] A pair of connecting pieces, arranged on the plurality of pole groups and located inside the cover plate, one ends of the pair of connecting pieces are respectively connected to the pair of pole columns, and the opposite ends both extend to the through hole and are connected to the ears;

[0009] A sealing plate and an insulating plate, arranged in the through hole, the sealing plate being provided with a first liquid injection hole, the insulating plate being provided with a second liquid injection hole communicated with the first liquid injection hole, a protruding part being formed on the lower peripheral wall of the lower end of the second liquid injection hole, and at least one first groove being arranged at the lower end of the protruding part, the first groove being communicated with the second liquid injection hole.

[0010] Beneficial effects: The present utility model has through holes opened on the cover plate. One end of the connecting piece is connected to the tab at the through hole, which can reduce the number of bends of the connecting piece and the tab, thereby reducing the thickness dimension of the battery cell. The other end of the connecting piece is connected to the terminal post, so that the terminal post and the tab are arranged in a dislocation manner, further reducing the thickness dimension of the battery cell and improving the space utilization rate of the battery cell. In addition, the first liquid injection hole and the second liquid injection hole are communicated to form a first liquid injection channel for injecting electrolyte. The first groove of the convex part is communicated with the second liquid injection hole, which can form a second liquid injection channel. In the case where the lower end opening of the second liquid injection hole is blocked, the electrolyte can be conducted by using the first groove, improving the reliability of the liquid injection process. Moreover, during the operation of vacuum pumping of the battery cell under negative pressure, gas can pass through from the first groove, which is convenient for use.

[0011] In an alternative embodiment, the first groove is a notch formed on the bottom surface of the convex part. The height H of the first groove satisfies: 0.3 mm ≤ H ≤ 5 mm, and the width W of the first groove satisfies: W ≥ 0.25 mm.

[0012] Beneficial effects: The first groove is a notch formed on the bottom surface of the convex part, which is convenient for processing. By defining the size of the first groove, it is beneficial to the smooth flow of the electrolyte.

[0013] In an alternative embodiment, the convex part is a sleeve, and the outer diameter D of the sleeve satisfies: D ≥ 3.6 mm.

[0014] Beneficial effects: The convex part is a sleeve, which is convenient for processing the first groove. Limiting the outer diameter of the sleeve can ensure the structural strength of the sleeve and the first groove.

[0015] In an alternative embodiment, a first boss is formed on the peripheral wall of the lower end of the first liquid injection hole, and a second boss is formed on the peripheral wall of the upper end of the second liquid injection hole.

[0016] Beneficial effects: By providing the first boss and the second boss, it is convenient for processing the convex part and can also prevent the sealing plate from contacting the tab and causing a short circuit.

[0017] In an alternative embodiment, the bottom surface of the sealing plate is connected to the top surface of the insulating plate, and the insulating plate forms a second groove corresponding to the first boss. The first boss is arranged in the second groove and there is a gap L between the first boss and the second groove, where L ≥ 0.15 mm.

[0018] Beneficial effects: The second groove is used for installing the first boss. There is a gap between the first boss and the second groove, which can ensure that the connection part between the bottom surface of the sealing plate and the top surface of the insulating plate is completely fitted, avoiding the first boss and the second boss from affecting the fixed connection between the sealing plate and the insulating plate, so as to ensure the connection strength between the sealing plate and the insulating plate.

[0019] In an alternative embodiment, the first liquid injection hole and the second liquid injection hole are circular holes arranged coaxially, and the aperture of the first liquid injection hole is smaller than that of the second liquid injection hole.

[0020] Advantageous effects: After the liquid injection is completed, it is necessary to seal the first liquid injection hole and the second liquid injection hole. Since the first liquid injection hole and the second liquid injection hole are coaxial, and the aperture of the first liquid injection hole is smaller than that of the second liquid injection hole, only by sealing the first liquid injection hole can it be ensured that the first liquid injection hole and the second liquid injection hole are sealed simultaneously, which is beneficial to saving the usage cost.

[0021] In an alternative embodiment, a stepped surface is provided along the circumferential side at the lower end of the through hole, the lower end of the sealing plate is connected to the stepped surface, and the circumferential wall of the sealing plate is connected to the hole wall of the through hole.

[0022] Advantageous effects: The stepped surface is provided at the lower end of the through hole to install the sealing plate. The stepped surface can effectively limit and support the sealing plate. The circumferential side of the sealing plate is connected to the hole wall of the first through hole, and the connection is firm and the reliability is strong.

[0023] In an alternative embodiment, the through hole includes a first sub-through hole and a second sub-through hole that are connected and communicate with each other. The stepped surface is formed between the first sub-through hole and the second sub-through hole. The first sub-through hole is provided at the upper end of the second sub-through hole. The bottom surface of the sealing plate abuts against the stepped surface, the circumferential wall of the sealing plate is welded to the hole wall of the first sub-through hole, and the insulating plate is provided in the second sub-through hole.

[0024] Advantageous effects: The first sub-through hole is used to install the sealing plate. The circumferential wall of the sealing plate is welded to the hole wall of the first sub-through hole to form a sealed welding surface, which improves the welding reliability between the sealing plate and the housing. The second sub-through hole can leave an installation space for the connecting piece and the pole ear and an installation space for the insulating plate, which is beneficial to reducing the occupied space of the connecting piece and the pole ear, thereby further improving the space utilization rate.

[0025] In an alternative embodiment, the pole ear includes a bent portion formed by converging the end of the pole group, and the bottom surface of the bent portion is welded to the upper surface of the connecting piece.

[0026] Advantageous effects: After the pole ear converges to form a bent portion, it only needs to be bent once to realize the welding with the connecting piece, and the connecting piece does not need to be bent. Therefore, the total number of bending times is less, reducing the thickness space occupied by the bending of the pole ear and the connecting piece, thereby improving the space utilization rate of the battery cell, and it can also omit the bending process of the connecting piece, improving the production efficiency of the battery cell.

[0027] In a second aspect, the present invention further provides a battery pack, including: a plurality of the above-mentioned battery cells.

[0028] Beneficial effects: Since the battery pack includes battery cells and has the same effects as the battery cells, that is, through holes are formed in the cover plate, one end of the connecting piece is connected to the tab at the through hole, which can reduce the number of bends of the connecting piece and the tab, thereby reducing the thickness dimension of the battery cell. The other end of the connecting piece is connected to the terminal, so that the terminal and the tab are arranged in a staggered manner, further reducing the thickness dimension of the battery cell and improving the space utilization rate of the battery cell. In addition, the first liquid injection hole and the second liquid injection hole are communicated to form a first liquid injection channel for injecting electrolyte. The first groove of the convex part is communicated with the second liquid injection hole, which can form a second liquid injection channel. When the lower end opening of the second liquid injection hole is blocked, the electrolyte can be conducted by using the first groove, improving the reliability of the liquid injection process. Moreover, during the operation of vacuum pumping of the battery cell, gas can pass through from the first groove, which is convenient for use. Brief Description of the Drawings

[0029] In order to more clearly illustrate the specific embodiments of the present invention 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 invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0030] Figure 1 Structural schematic diagram of a battery cell according to an embodiment of the present invention;

[0031] Figure 2 Partial top view of a battery cell according to an embodiment of the present invention;

[0032] Figure 3 For Figure 2 Cross-sectional view at A in

[0033] Figure 4 For Figure 3 Enlarged view at B in

[0034] Figure 5 Structural schematic diagram of the sealing plate and the insulating plate of a battery cell according to an embodiment of the present invention;

[0035] Figure 6 Partial structural schematic diagram of the insulating plate of a battery cell according to an embodiment of the present invention;

[0036] Figure 7 Structural schematic diagram of the cover plate of a battery cell according to an embodiment of the present invention;

[0037] Figure 8 Partial structural schematic diagram of a battery cell according to an embodiment of the present invention;

[0038] Figure 9Schematic structural diagram of the tab and connecting piece of a battery cell according to an embodiment of the present utility model.

[0039] Explanation of reference numerals:

[0040] 1. Housing; 2. Electrode assembly; 3. Tab; 301. Bent portion; 4. Cover plate; 401. Through hole; 4011. First sub-through hole; 4012. Second sub-through hole; 402. Step surface; 5. Terminal; 6. Connecting piece; 7. Sealing plate; 701. First liquid injection hole; 702. First boss; 8. Insulating plate; 801. Second liquid injection hole; 802. Second boss; 803. Protrusion; 804. First groove; 805. Second groove. Detailed implementation manners

[0041] 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. Apparently, the described embodiments are some, but not all, of the embodiments of the present utility model. All other embodiments obtained by those skilled 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.

[0042] The following will describe the embodiments of the present utility model in conjunction with Figures 1 to 9 , describing the embodiments of the present utility model.

[0043] According to an embodiment of the present utility model, on the one hand, as shown in Figure 1 and Figure 2 , a battery cell is provided, mainly including: a housing 1, a cover plate 4, a pair of connecting pieces 6, a sealing plate 7, and an insulating plate 8. The housing 1 is provided with an opening, a plurality of electrode assemblies 2 disposed in the opening, and a plurality of pairs of tabs 3 corresponding to the electrode assemblies 2 one by one. The cover plate 4 covers the opening. The cover plate 4 is provided with a through hole 401 and a pair of terminals 5. The through hole 401 is located between the pair of terminals 5. A pair of connecting pieces 6 are disposed on the plurality of electrode assemblies 2 and located inside the cover plate 4. One ends of the pair of connecting pieces 6 are respectively connected to the pair of terminals 5, and the opposite ends both extend to the through hole 401 and are connected to the tabs 3. The sealing plate 7 and the insulating plate 8 are disposed in the through hole 401. The sealing plate 7 is provided with a first liquid injection hole 701. The insulating plate 8 is provided with a second liquid injection hole 801 communicating with the first liquid injection hole 701. The lower peripheral wall of the second liquid injection hole 801 forms a protrusion 803. At least one first groove 804 is provided at the lower end of the protrusion 803. The first groove 804 communicates with the second liquid injection hole 801.

[0044] The battery cell provided by the embodiment of the present utility model has a through hole 401 formed in the cover plate 4. One end of the connecting piece 6 is connected to the tab 3 at the through hole 401, which can reduce the number of bends of the connecting piece 6 and the tab 3, thereby reducing the thickness dimension of the battery cell. The other end of the connecting piece 6 is connected to the terminal 5, so that the terminal 5 and the tab 3 are arranged in a staggered manner, further reducing the thickness dimension of the battery cell and improving the space utilization rate of the battery cell. In addition, the first liquid injection hole 701 and the second liquid injection hole 801 are communicated to form a first liquid injection channel for injecting electrolyte. The first groove 804 of the convex portion 803 is communicated with the second liquid injection hole 801, which can form a second liquid injection channel. In the case where the lower end opening of the second liquid injection hole 801 is blocked, the electrolyte can be conducted through the first groove 804, improving the reliability of the liquid injection process. Moreover, during the operation of vacuum pumping of the battery cell under negative pressure, gas can pass through from the first groove 804, which is convenient for use.

[0045] Specifically, the cover plate 4 is provided with a through hole 401 along the length direction, and the through hole 401 is rectangular. As Figure 1 shown, the four sides of the housing 1 are provided with side plates, the bottom is provided with a bottom plate, and the top forms an opening. The four side plates, the bottom plate and the cover plate 4 enclose a closed cavity. The top and bottom directions of the embodiment of the present utility model are as Figure 1 shown.

[0046] As Figure 9 shown, multiple pairs of electrode groups 2 are stacked and arranged in the cavity. Multiple pairs of electrode groups 2 are provided with multiple pairs of tabs 3 on the side close to the opening. Each electrode group 2 is correspondingly provided with a positive tab and a negative tab. The through hole 401 of the cover plate 4 is used to leave a connection space for the connecting piece 6 and the tab 3. Since the terminal 5 is arranged on the cover plate 4, the tab 3 and the terminal 5 are arranged in a staggered manner, so that the installation thickness can be reduced and the installation is also convenient. The connecting piece 6 is arranged on the electrode group 2, and the tab 3 is bent and welded on the top surface of the connecting piece 6, and a layer of high-temperature tape is covered on the upper surfaces of multiple tabs 3.

[0047] A pair of terminals 5 includes a positive terminal and a negative terminal. Correspondingly, the tab 3 includes a positive tab and a negative tab. One of the connecting pieces 6 connects the positive terminal and the positive tabs of multiple electrode groups 2, and the other connecting piece 6 connects the negative terminal and the negative tabs of multiple electrode groups 2. The connecting piece 6 needs to be conductive to realize the electrical connection between the tab 3 and the terminal 5. A gap is left between the two connecting pieces 6 to prevent the positive terminal from being short-circuited with the negative terminal.

[0048] It should be noted that the embodiment of the present utility model does not limit the number of the electrode groups 2, which can be selected according to needs, for example, one, two or more than two can be selected. Exemplarily, as Figure 9 shown, two electrode groups 2 are provided. Each of the two electrode groups 2 is provided with a positive tab and a negative tab on the side close to the opening.

[0049] In addition, the embodiments of the present utility model do not limit the connection between the connecting piece 6 and the pole column 5 and the pole ear 3, and any existing connection form can be selected according to needs. In order to improve the connection stability between the connecting piece 6 and the pole column 5 and the pole ear 3, in one embodiment, the opposite ends of the connecting piece 6 are respectively welded to the pole column 5 and the pole ear 3.

[0050] It should be noted that the embodiments of the present utility model do not limit the structure and quantity of the first groove 804, and any existing structure can be selected according to needs, and the quantity can be correspondingly selected. Exemplarily, as Figure 6 shown, the first groove 804 is a U-shaped groove, four are provided, and are evenly distributed at the bottom of the convex portion 803.

[0051] In one embodiment, as Figure 6 shown, the first groove 804 is a notch formed on the bottom surface of the convex portion 803, which is convenient for processing. As Figure 4 shown, the height H of the first groove 804 satisfies: 0.3 mm ≤ H ≤ 5 mm, and the width W of the first groove 804 satisfies: W ≥ 0.25 mm. By defining the size of the first groove 804, it is beneficial to the smooth flow of the electrolyte.

[0052] Furthermore, in one embodiment, as Figure 6 shown, the convex portion 803 is a sleeve, and the outer diameter D of the sleeve ≥ 3.6 mm. The convex portion 803 being a sleeve is convenient for processing the first groove 804, and limiting the outer diameter of the sleeve can ensure the structural strength of the sleeve and the first groove 804.

[0053] In one embodiment, as Figure 4 shown, a first boss 702 is formed on the peripheral wall at the lower end of the first liquid injection hole 701, and a second boss 802 is formed on the peripheral wall at the upper end of the second liquid injection hole 801. The second boss 802 is integrally formed with the convex portion 803. By providing the first boss 702 and the second boss 802, it is convenient for processing the convex portion 803, and it can also prevent the sealing plate 7 from contacting and short-circuiting with the pole ear 3.

[0054] For the convenience of use, both the first liquid injection hole 701 and the second liquid injection hole 801 can adopt circular holes. The first boss 702 is a first circular platform formed by the lower end of the first liquid injection hole 701 extending axially. The second boss 802 is a second circular platform formed by the upper end of the second liquid injection hole 801 extending axially.

[0055] Further, in one embodiment, as Figure 4 and Figure 5As shown, the bottom surface of the sealing plate 7 is connected to the top surface of the insulating plate 8, and the insulating plate 8 forms a second groove 805 corresponding to the first boss 702. The first boss 702 is disposed in the second groove 805, and a gap L is left between the first boss 702 and the second groove 805, where L≥0.15 mm. The second groove 805 is used for installing the first boss 702. A gap is left between the first boss 702 and the second groove 805, which can ensure that the connection part between the bottom surface of the sealing plate 7 and the top surface of the insulating plate 8 is completely fitted, and avoid the influence of the first boss 702 and the second boss 802 on the fixed connection between the sealing plate 7 and the insulating plate 8, so as to ensure the connection strength between the sealing plate 7 and the insulating plate 8.

[0056] In one embodiment, as Figure 4 shown, the first liquid injection hole 701 and the second liquid injection hole 801 are circular holes arranged coaxially, and the aperture of the first liquid injection hole 701 is smaller than the aperture of the second liquid injection hole 801. After the liquid injection is completed, the first liquid injection hole 701 and the second liquid injection hole 801 need to be closed. Since the first liquid injection hole 701 and the second liquid injection hole 801 are coaxially arranged and the aperture of the first liquid injection hole 701 is smaller than the aperture of the second liquid injection hole 801, only the first liquid injection hole 701 needs to be closed to ensure that the first liquid injection hole 701 and the second liquid injection hole 801 are closed simultaneously, which is beneficial to saving the use cost.

[0057] Specifically, after the liquid injection is completed, a rubber nail is arranged at the first liquid injection hole 701 to seal the first liquid injection hole 701. A third groove is further formed at the upper end of the first liquid injection hole 701, and a sealing plate is hermetically arranged at the third groove to further seal the first liquid injection hole 701.

[0058] In one embodiment, as Figure 7 and Figure 8 shown, a step surface 402 is arranged along the circumferential side at the lower end of the through hole 401, the lower end of the sealing plate 7 is connected to the step surface 402, and the circumferential wall of the sealing plate 7 is connected to the hole wall of the through hole 401. The step surface 402 is arranged at the lower end of the through hole 401 to install the sealing plate 7. The step surface 402 can effectively limit and support the sealing plate 7, and the circumferential side of the sealing plate 7 is connected to the hole wall of the first through hole 401, with firm connection and strong reliability.

[0059] Furthermore, in one embodiment, as Figure 8As shown, the through hole 401 includes a first sub-through hole 4011 and a second sub-through hole 4012 that are connected and communicate with each other. The length of the first sub-through hole 4011 is greater than the length of the second sub-through hole 4012, or the width of the first sub-through hole 4011 is greater than the width of the second sub-through hole 4012, so as to form a stepped surface 402 between the first sub-through hole 4011 and the second sub-through hole 4012. The first sub-through hole 4011 is provided at the upper end of the second sub-through hole 4012. The bottom surface of the sealing plate 7 abuts against the stepped surface 402, the peripheral wall of the sealing plate 7 is welded to the hole wall of the first sub-through hole 4011, and the insulating plate 8 is arranged in the second sub-through hole 4012.

[0060] The first sub-through hole 4011 is used to install the sealing plate 7. The peripheral wall of the sealing plate 7 is welded to the hole wall of the first sub-through hole 4011 to form a sealed welding surface, which improves the welding reliability between the sealing plate 7 and the housing 1. The second sub-through hole 4012 can leave an installation space for the connecting piece 6 and the tab 3 and an installation space for the insulating plate 8, which is beneficial to reducing the occupied space of the connecting piece 6 and the tab 3, thereby further improving the space utilization rate.

[0061] In one embodiment, as Figure 9 shown, the tab 3 includes a bent portion 301 formed by converging the end of the electrode group 2. The bottom surface of the bent portion 301 is welded to the upper surface of the connecting piece 6. After the tab 3 converges to form the bent portion 301, it only needs to be bent once to realize the welding with the connecting piece 6, and the connecting piece 6 does not need to be bent. Therefore, the total number of bending times is less, reducing the thickness space occupied by the bending of the tab 3 and the connecting piece 6, thereby improving the space utilization rate of the battery cell. Moreover, the bending process of the connecting piece 6 can be omitted, improving the production efficiency of the battery cell.

[0062] According to an embodiment of the present invention, on the other hand, a battery pack is further provided, which mainly includes: a plurality of battery cells.

[0063] Since the battery pack includes battery cells, it has the same effects as the battery cells, that is, through holes 401 are opened on the cover plate 4, one end of the connecting piece 6 is connected to the tab 3 at the through holes 401, which can reduce the number of bending times of the connecting piece 6 and the tab 3, thereby reducing the thickness dimension of the battery cell. The other end of the connecting piece 6 is connected to the terminal post 5, so that the terminal post 5 and the tab 3 are arranged in a staggered manner, further reducing the thickness dimension of the battery cell and improving the space utilization rate of the battery cell. In addition, the first liquid injection hole 701 and the second liquid injection hole 801 are communicated to form a first liquid injection channel for injecting electrolyte. The first groove 804 of the convex portion 803 is communicated with the second liquid injection hole 801, which can form a second liquid injection channel. In the case where the lower end opening of the second liquid injection hole 801 is blocked, the electrolyte can be conducted by using the first groove 804, improving the reliability of the liquid injection process. Moreover, during the operation of vacuum pumping the battery cell to a negative pressure, gas can pass through from the first groove 804, which is convenient for use.

[0064] Specifically, multiple battery cells can be connected in series, in parallel, or in a combination of series and parallel. In this regard, the embodiments of the present invention do not impose any specific limitations.

[0065] Although the embodiments of the present invention 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 invention, and such modifications and variations fall within the scope defined by the appended claims.

Claims

1. A battery cell, characterized in that: include: A shell having an opening, a plurality of pole groups arranged in the opening, and a plurality of pairs of pole ears corresponding to the pole groups one by one; A cover plate, covering the opening, wherein a through hole and a pair of poles are provided on the cover plate, wherein the through hole is located between the pair of poles; A pair of connecting pieces, provided on the plurality of pole groups and located on the inner side of the cover plate, one end of the pair of connecting pieces being connected to a pair of poles respectively, and the other ends of the pair of connecting pieces extending to the through holes and connected to the pole ears; A sealing plate and an insulating plate are arranged in the through hole, the sealing plate is provided with a first injection hole, the insulating plate is provided with a second injection hole connected with the first injection hole, a convex portion is formed on the lower end peripheral wall of the second injection hole, and at least one first groove is provided at the lower end of the convex portion, and the first groove is connected with the second injection hole.

2. The battery cell according to claim 1, characterized in that: The first groove is a notch formed on the bottom surface of the raised portion, and a height H of the first groove satisfies: 0.3 mm ≤ H ≤ 5 mm, and a width W of the first groove satisfies: W ≥ 0.25 mm.

3. The battery cell according to claim 2, characterized in that: The protruding portion is a sleeve, and the outer diameter D of the sleeve is ≥3.6 mm.

4. The battery cell according to any one of claims 1 to 3, characterized in that: The lower end peripheral wall of the first liquid injection hole forms a first boss, and the upper end peripheral wall of the second liquid injection hole forms a second boss.

5. The battery cell according to claim 4, characterized in that: The bottom surface of the sealing plate is connected to the top surface of the insulating plate, and the insulating plate forms a second groove corresponding to the first boss. The first boss is arranged in the second groove, and a gap L is left between the first boss and the second groove, where L≥0.15 mm.

6. The battery cell according to any one of claims 1 to 3, characterized in that: The first injection hole and the second injection hole are coaxially arranged circular holes, and the aperture of the first injection hole is smaller than the aperture of the second injection hole.

7. The battery cell according to any one of claims 1 to 3, characterized in that: The lower end of the through hole is provided with a step surface along the circumferential side, the lower end of the sealing plate is connected to the step surface, and the circumferential wall of the sealing plate is connected to the hole wall of the through hole.

8. The battery cell according to claim 7, characterized in that: The through hole includes a first sub-through hole and a second sub-through hole that are connected to each other, the step surface is formed between the first sub-through hole and the second sub-through hole, the first sub-through hole is arranged at the upper end of the second sub-through hole, the bottom surface of the sealing plate abuts against the step surface, the peripheral wall of the sealing plate is welded to the hole wall of the first sub-through hole, and the insulating plate is arranged in the second sub-through hole.

9. The battery cell according to any one of claims 1 to 3, characterized in that: The electrode tab includes a bent portion formed by gathering the ends of the electrode group, and the bottom surface of the bent portion is welded to the upper surface of the connecting piece.

10. A battery pack, characterized in that: include: A plurality of battery cells according to any one of claims 1 to 9.

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