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. Wherein the battery cell comprises a cover plate and a sealing plate, two through holes are formed in the cover plate at intervals, each through hole is provided with a stepped groove arranged around the inner wall of the through hole, the stepped groove comprises a first groove section and a second groove section which are arranged up and down, the size of the first groove section is larger than that of the second groove section, and a stepped surface is formed at the joint of the first groove section and the second groove section; the bottom face of the sealing plate abuts against the step face, and the side wall of the sealing plate is welded to the inner wall of the first groove section. According to the utility model, the two through holes are formed in the cover plate, and the welding bottom plate and the tabs can be welded and connected through the through holes, so that the situation that the tabs are bent after being welded to occupy the space is avoided, the length of the tabs is shortened, the use space of the accommodating cavity in the shell in the length direction is increased, and the utilization rate of the internal space of the battery cell is increased. The step surface is abutted against the bottom surface of the sealing plate, so that the sealing plate can be tightly contacted with the through hole, and the sealing performance is improved.

Description

Technical Field

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

[0002] With the increasing maturity of battery technology, batteries are widely used in electric vehicles and energy storage fields, and the requirements for the use performance and safety of batteries are increasing day by day. A battery cell is the basic component unit of a battery and can independently generate and store electric energy.

[0003] In the prior art, both the connecting piece and the tab need to be bent, and the connecting piece, the terminal post and the tab are usually located on the same vertical plane, so a large space inside the battery cell needs to be occupied, resulting in low space utilization rate of the battery cell. Summary of the Utility Model

[0004] In view of this, the utility model provides a battery cell and a battery pack to solve the problem of low space utilization rate of the battery cell.

[0005] In a first aspect, the utility model provides a battery cell, comprising:

[0006] A cover plate, provided with two through holes at intervals along the length direction, each of the through holes is provided with a stepped groove arranged around the inner wall of the through hole, the stepped groove comprises a first groove section and a second groove section arranged up and down, the size of the first groove section is larger than that of the second groove section, and a step surface is formed at the connection between the first groove section and the second groove section;

[0007] A sealing plate, correspondingly covering the through hole, the bottom surface of the sealing plate abuts against the step surface, and the side wall of the sealing plate is welded to the inner wall of the first groove section.

[0008] Beneficial effects: For this battery cell, when assembling the battery cell, first place the electrode assembly into the accommodation cavity of the housing from the opening of the housing, and cover the cover plate on the opening of the housing. Since there are two through holes on the cover plate and the positions of the two through holes correspond to those of the negative tab and the positive tab, the negative tab and the positive tab on the electrode assembly respectively pass through the two through holes on the cover plate. The installer can bend the negative tab and the positive tab through the through holes, so that the negative tab and the positive welding tab respectively abut against the negative welding bottom plate and the positive welding bottom plate. The installer can also weld and fix the negative welding bottom plate and the negative tab, and the positive welding bottom plate and the positive tab through the through holes. Finally, cover the sealing plate on the through hole to seal the accommodation cavity, and complete the assembly of the battery cell.

[0009] By providing two through holes in the cover plate, the welding bottom plate and the tab can be welded and connected through the through holes, thereby avoiding the space occupied by the tab after welding and bending, shortening the length of the tab, increasing the usable space of the accommodation cavity in the housing in the length direction, and thus improving the internal space utilization rate of the battery cell. Since the inner wall of the through hole is provided with a stepped groove, and a step surface is formed at the connection between the first groove section and the second groove section of the stepped groove, the step surface abuts against the bottom surface of the sealing plate, and the side wall of the sealing plate and the inner wall of the first groove section are welded, which can ensure the close contact between the sealing plate and the through hole, improve the sealing performance, reduce the risk of electrolyte leakage, and the welding between the side wall of the sealing plate and the inner wall of the through hole enhances the connection strength and further improves the sealing effect.

[0010] In an alternative embodiment, the thickness of the sealing plate is less than the groove depth of the first groove section.

[0011] Beneficial effects: By setting the thickness of the sealing plate to be less than the groove depth of the first groove section, on the one hand, it can ensure that the bumps at the welding joint between the sealing plate and the first groove section do not protrude above the upper surface of the cover plate, ensuring the flatness of the upper surface of the cover plate, which is beneficial to the assembly of subsequent other components and avoids interference between the welding bumps and other components during the assembly process. On the other hand, it ensures that after the sealing plate and the first groove section are matched, the sealing plate only occupies the space at the cover plate, avoiding the sealing plate extending into the housing and occupying the internal space of the housing, thereby improving the internal space utilization rate of the battery cell.

[0012] In an alternative embodiment, the thickness of the sealing plate is 0.2 mm to 0.4 mm smaller than the groove depth of the first groove section.

[0013] Beneficial effects: Setting the thickness of the sealing plate to be 0.2 mm to 0.4 mm smaller than the groove depth of the first groove section can further ensure that the bumps at the welding joint between the sealing plate and the first groove section do not protrude above the upper surface of the cover plate, ensuring the flatness of the upper surface of the cover plate, which is beneficial to the assembly of subsequent other components and avoids interference between the welding bumps and other components during the assembly process.

[0014] In an alternative embodiment, the groove depth of the first groove section is t, and the thickness of the cover plate is T, and 0.25T ≤ t ≤ 0.8T.

[0015] Beneficial effects: By controlling the ratio of the thickness of the cover plate to the groove depth of the first groove section, on the one hand, it can ensure the close contact between the sealing plate and the inner wall of the first groove section, improve the sealing performance, and at the same time ensure the strength and welding tightness after the sealing plate and the inner wall of the first groove section are welded. On the other hand, it can improve the structural stability of the cover plate.

[0016] In an alternative embodiment, a first chamfer is provided around the top of the inner wall of each through hole, and a second chamfer is provided around the bottom of the side wall of each sealing plate.

[0017] Beneficial effects: The design of the first chamfer and the second chamfer helps to guide the sealing plate accurately into the through hole, simplifies the assembly process, reduces the friction between the sealing plate and the inner wall of the through hole during the assembly process, and facilitates the smooth insertion of the sealing plate into the through hole.

[0018] In an alternative embodiment, a pole group is further included. Negative and positive pole tabs are provided at the end of the pole group. The sealing plate includes a cover body and a plastic plate. The plastic plate is disposed on one side of the cover body and is located between the negative and positive pole tabs and the cover body.

[0019] Beneficial effects: By providing a plastic plate between the negative and positive pole tabs and the cover body, the plastic plate prevents the negative and positive pole tabs from directly contacting the cover body, avoiding short - circuit of the battery cell. At the same time, the plastic plate can improve the sealing performance between the sealing plate and the top wall, ensure the sealing inside the battery cell, and prevent electrolyte leakage.

[0020] In an alternative embodiment, the bottom surface of the cover body abuts against the stepped surface.

[0021] Beneficial effects: By abutting the bottom surface of the cover body against the stepped surface, the contact part between the sealing plate and the stepped surface is firmly and stably fixed, improving the structural stability of the entire assembly. Since the plastic plate is relatively soft, the abutment of the bottom surface of the cover body against the stepped surface can prevent the soft plastic plate from deforming when it abuts against the stepped surface.

[0022] In an alternative embodiment, a negative welding bottom plate and a positive welding bottom plate are further included. The negative welding bottom plate and the positive welding bottom plate are disposed below the cover plate, and the negative welding bottom plate and the positive welding bottom plate respectively extend to the corresponding through holes.

[0023] Beneficial effects: By arranging the positive welding bottom plate and the negative welding bottom plate below the cover plate and extending them to the through holes, and by bending the negative and positive pole tabs, the negative welding bottom plate and the positive welding bottom plate are correspondingly abutted against the negative and positive pole tabs. Installers can weld and fix the negative welding bottom plate and the negative pole tab, and the positive welding bottom plate and the positive pole tab through the through holes.

[0024] In an alternative embodiment, a plastic part is further included. The plastic part is disposed between the negative welding bottom plate and the positive welding bottom plate and the cover plate, and through holes corresponding to the through holes are provided on the plastic part.

[0025] Beneficial effects: A plastic part is arranged between the positive welding bottom plate and the negative welding bottom plate and the cover plate. The plastic part ensures insulation between the positive welding bottom plate, the negative welding bottom plate and the cover plate. Since through holes corresponding to the through holes are formed in the plastic part, the negative electrode tab and the positive electrode tab can pass through the through holes of the plastic part and pass out through the through holes.

[0026] In a second aspect, the present invention further provides a battery pack, including: a plurality of battery cells.

[0027] Beneficial effects: This battery pack includes the battery cells as described above, and has all the beneficial technical effects of the battery cells, which will not be elaborated here. Description of the drawings

[0028] 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 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 also be obtained based on these drawings.

[0029] Figure 1 It is a schematic structural diagram of a battery cell according to an embodiment of the present invention;

[0030] Figure 2 It is a cross-sectional view of a battery cell according to an embodiment of the present invention;

[0031] Figure 3 It is Figure 2 a partially enlarged schematic view of the mating part of the middle cover plate and the sealing plate;

[0032] Figure 4 It is a schematic structural diagram of a battery cell without a sealing plate according to an embodiment of the present invention;

[0033] Figure 5 It is Figure 4 a cross-sectional view of the battery cell shown;

[0034] Figure 6 It is a schematic structural diagram of a battery cell without a sealing plate according to an embodiment of the present invention;

[0035] Figure 7 It is a schematic structural diagram of a pole group in a battery cell according to an embodiment of the present invention.

[0036] Description of the reference numerals:

[0037] 1. Cover plate; 101. Through hole; 1011. Step groove; 10111. First groove section; 10112. Second groove section; 1012. First chamfer; 2. Negative electrode tab; 3. Positive electrode tab; 4. Sealing plate; 401. Second chamfer; 402. Cover body; 403. Plastic plate; 5. Negative electrode welding bottom plate; 6. Positive electrode welding bottom plate; 7. Plastic part; 8. Housing; 9. Electrode group. Detailed implementation manners

[0038] 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 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.

[0039] In related technologies, both the connecting piece and the tab need to be bent, and the connecting piece, the pole column, and the tab are usually located on the same vertical plane. Therefore, a relatively large space inside the battery cell needs to be occupied, resulting in a low space utilization rate of the battery cell.

[0040] To solve the above technical problems, the embodiments of the present utility model will be described below in conjunction with Figures 1 to 7 , to describe the embodiments of the present utility model.

[0041] According to the embodiments of the present utility model, on the one hand, as Figures 1 to 7 shown, a battery cell is provided, including a cover plate 1 and a sealing plate 4.

[0042] Specifically, as Figures 1 to 6 shown, two through holes 101 are provided at intervals along the length direction of the cover plate 1. Each through hole 101 is provided with a step groove 1011 arranged around the inner wall of the through hole 101. As Figure 3 shown, the step groove 1011 includes a first groove section 10111 and a second groove section 10112. Among them, the first groove section 10111 and the second groove section 10112 are arranged up and down. The size of the first groove section 10111 is larger than that of the second groove section 10112, and a step surface is formed at the connection between the first groove section 10111 and the second groove section 10112.

[0043] Specifically, as Figures 1 to 6 shown, the sealing plates 4 are arranged in one-to-one correspondence with the through holes 101. The sealing plates 4 are respectively covered at the positions of the through holes 101 in one-to-one correspondence. The bottom surface of the sealing plate 4 abuts against the step surface.

[0044] For this battery cell, when assembling the battery cell, first place the electrode assembly 9 into the accommodation cavity of the housing 8 through the opening of the housing 8, and cover the cover plate 1 on the opening of the housing 8. Since two through holes 101 are provided on the cover plate 1 and the positions of the two through holes 101 correspond to the positions of the negative electrode tab 2 and the positive electrode tab 3, the negative electrode tab 2 and the positive electrode tab 3 on the electrode assembly 9 respectively pass through the two through holes 101 on the cover plate 1. The installer can bend the negative electrode tab 2 and the positive electrode tab through the through holes 101, so that the negative electrode tab 2 and the positive welding tab respectively abut against the negative welding bottom plate 5 and the positive welding bottom plate 6 correspondingly. The installer can also weld and fix the negative welding bottom plate 5 and the negative electrode tab 2, and the positive welding bottom plate 6 and the positive electrode tab 3 through the through holes 101. Finally, cover the sealing plate 4 at the through holes 101 and seal the accommodation cavity to complete the assembly of the battery cell.

[0045] By providing two through holes 101 on the cover plate 1, the welding connection between the welding bottom plate and the electrode tab can be carried out through the through holes 101, thereby avoiding the space occupied by the bending of the electrode tab after welding, shortening the length of the electrode tab, improving the use space of the accommodation cavity in the housing 8 in the length direction, and thus improving the utilization rate of the internal space of the battery cell. Since the inner wall of the through hole 101 is provided with a stepped groove 1011, and a step surface is formed at the connection between the first groove section 10111 and the second groove section 10112 of the stepped groove 1011, by abutting the step surface against the bottom surface of the sealing plate 4 and welding the side wall of the sealing plate 4 and the inner wall of the first groove section 10111, the close contact between the sealing plate 4 and the through hole 101 can be ensured, improving the sealing performance and reducing the risk of electrolyte leakage. The welding of the side wall of the sealing plate 4 and the inner wall of the through hole 101 enhances the connection strength and further improves the sealing effect.

[0046] Specifically, the through holes 101 can be provided in the middle area of the cover plate 1 or in the end area close to the cover plate 1, as long as the positions of the positive electrode tab 3 and the negative electrode tab 2 correspond to the positions of the through holes 101. The through holes 101 can be set in any existing shape such as a rounded rectangular hole, a square hole, a circular hole, etc. In the embodiments of the present application, the shape of the through holes 101 and their positions on the cover plate 1 are not specifically limited.

[0047] Specifically, the sizes of the first groove section 10111 and the second groove section 10112 can be adjusted according to the design requirements, and then the size of the step surface can be adjusted. In the embodiments of the present application, the sizes of the first groove section 10111 and the second groove section 10112 are not specifically limited.

[0048] Specifically, the shape and size of the sealing plate 4 are adapted to the shape and size of the through hole 101. In the embodiments of the present application, the shape and size of the sealing plate 4 are not specifically limited.

[0049] Specifically, the stepped surface formed at the first slot section 10111 and the second slot section 10112 can be an inclined surface or a horizontal surface. In the embodiments of the present application, the type of the stepped surface is not specifically limited.

[0050] In one embodiment, as Figure 3 shown, the thickness of the sealing plate 4 is less than the slot depth of the first slot section 10111.

[0051] By setting the thickness of the sealing plate 4 to be less than the slot depth of the first slot section 10111, on the one hand, it can ensure that the bumps at the welding joint of the sealing plate 4 and the first slot section 10111 do not protrude above the upper surface of the cover plate 1, guarantee the flatness of the upper surface of the cover plate 1, which is beneficial to the assembly of other subsequent components, and avoid interference between the welding bumps and other components during the assembly process. On the other hand, it ensures that after the sealing plate 4 is matched with the first slot section 10111, the sealing plate 4 only occupies the space at the cover plate 1, and avoids the sealing plate 4 extending into the housing 8 and occupying the internal space of the housing 8, thereby improving the utilization rate of the internal space of the battery cell.

[0052] Specifically, the thickness of the sealing plate 4 and the slot depth of the first slot section 10111 are related to the thickness of the cover plate 1. When designing the thickness of the sealing plate 4 and the slot depth of the first slot section 10111, they can be adjusted according to the thickness of the cover plate 1. In the embodiments of the present application, the thickness of the sealing plate 4 and the slot depth of the first slot section 10111 are not specifically limited.

[0053] In one embodiment, as Figure 3 shown, the thickness of the sealing plate 4 is 0.2 mm to 0.4 mm smaller than the slot depth of the first slot section 10111.

[0054] Setting the thickness of the sealing plate 4 to be 0.2 mm to 0.4 mm smaller than the slot depth of the first slot section 10111 can further ensure that the bumps at the welding joint of the sealing plate 4 and the first slot section 10111 do not protrude above the upper surface of the cover plate 1, guarantee the flatness of the upper surface of the cover plate 1, which is beneficial to the assembly of other subsequent components, and avoid interference between the welding bumps and other components during the assembly process.

[0055] Specifically, when the thickness of the sealing plate 4 is 0.2 mm smaller than the slot depth of the first slot section 10111, the height of the bumps at the welding joint of the sealing plate 4 and the first slot section 10111 should be less than 0.2 mm. When the thickness of the sealing plate 4 is 0.4 mm smaller than the slot depth of the first slot section 10111, the height of the bumps at the welding joint of the sealing plate 4 and the first slot section 10111 should be less than 0.4 mm.

[0056] In one embodiment, as Figure 3 shown, the slot depth of the first slot section 10111 is t, and the thickness of the cover plate 1 is T, where 0.25T ≤ t ≤ 0.8T.

[0057] By controlling the ratio of the thickness of the cover plate 1 to the depth of the first groove section 10111, on the one hand, it can ensure the close contact between the sealing plate 4 and the inner wall of the first groove section 10111, improve the sealing performance, and at the same time ensure the strength and welding tightness after the sealing plate 4 is welded to the inner wall of the first groove section 10111. On the other hand, it can improve the structural stability of the cover plate 1.

[0058] In one embodiment, as Figure 3 shown, a first chamfer 1012 is provided around the top of the inner wall of each through hole 101, and a second chamfer 401 is provided around the bottom of the side wall of each sealing plate 4.

[0059] The design of the first chamfer 1012 and the second chamfer 401 helps to guide the sealing plate 4 to be accurately inserted into the through hole 101, simplifies the assembly process, reduces the friction between the sealing plate 4 and the inner wall of the through hole 101 during the assembly process, and facilitates the smooth insertion of the sealing plate 4 into the through hole 101.

[0060] Specifically, the first chamfer 1012 and the second chamfer 401 can be set as arc chamfers or bevel chamfers, etc. In the embodiments of the present application, the types of the first chamfer 1012 and the second chamfer 401 are not specifically limited.

[0061] In one embodiment, as Figure 7 shown, it further includes a pole group 9. The end of the pole group 9 is provided with a negative pole tab 2 and a positive pole tab 3. As Figure 3 shown, the sealing plate 4 includes a cover body 402 and a plastic plate 403. The plastic plate 403 is arranged on one side of the cover body 402, and the plastic plate 403 is arranged between the negative pole tab 2 and the positive pole tab 3 and the cover body 402.

[0062] By arranging the plastic plate 403 between the negative pole tab 2 and the positive pole tab 3 and the cover body 402, the plastic plate 403 is used to prevent the negative pole tab 2 and the positive pole tab 3 from directly contacting the cover body 402, avoid short - circuit of the battery cell, and at the same time the plastic plate 403 can improve the sealing performance between the sealing plate 4 and the top wall, ensure the tightness inside the battery cell, and prevent electrolyte leakage.

[0063] Specifically, the cover body 402 and the plastic plate 403 can be fixed by bonding, or can be fixed by injection molding or hot melting. In the embodiments of the present application, the connection method between the cover body 402 and the plastic plate 403 is not specifically limited.

[0064] Specifically, the plastic plate 403 can be made of PP material. In the embodiments of the present application, the material of the plastic plate 403 is not specifically limited.

[0065] In one embodiment, as Figure 3As shown, the bottom surface of the cover body 402 abuts against the stepped surface.

[0066] By making the bottom surface of the cover body 402 abut against the stepped surface, the contact part between the sealing plate 4 and the stepped surface is fixed firmly and stably, improving the structural stability of the entire assembly. Since the plastic plate 403 is relatively soft, by the abutment of the bottom surface of the cover body 402 against the stepped surface, deformation of the soft plastic plate 403 when it abuts against the stepped surface can be avoided.

[0067] Specifically, as Figure 3 shown, the area of the plastic plate 403 is smaller than the area of the cover body 402, so that the cover body 402 abuts against the stepped surface.

[0068] In one embodiment, as Figures 1 to 7 shown, it further includes a negative electrode welding bottom plate 5 and a positive electrode welding bottom plate 6. The negative electrode welding bottom plate 5 and the positive electrode welding bottom plate 6 are both arranged below the cover plate 1, and the negative electrode welding bottom plate 5 and the positive electrode welding bottom plate 6 respectively extend to the corresponding through holes 101.

[0069] By arranging the positive electrode welding bottom plate 6 and the negative electrode welding bottom plate 5 below the cover plate 1 and making the positive electrode welding bottom plate 6 and the negative electrode welding bottom plate 5 extend to the through holes 101, by bending the negative electrode tab 2 and the positive electrode tab 3, the negative electrode welding bottom plate 5 and the positive electrode welding bottom plate 6 are made to abut against the negative electrode tab 2 and the positive electrode tab 3 correspondingly. Installers can weld and fix the negative electrode welding bottom plate 5 and the negative electrode tab 2, and the positive electrode welding bottom plate 6 and the positive electrode tab 3 through the through holes 101.

[0070] Specifically, the negative electrode welding bottom plate 5 and the negative electrode pole can be fixed on the cover plate 1 by riveting, and the positive electrode welding bottom plate 6 and the positive electrode pole can be fixed on the cover plate 1 by riveting.

[0071] In one embodiment, as Figure 5 shown, it further includes a plastic part 7. The plastic part 7 is arranged between the negative electrode welding bottom plate 5 and the positive electrode welding bottom plate 6 and the cover plate 1, and through holes corresponding to the through holes 101 are formed in the plastic part 7.

[0072] By arranging the plastic part 7 between the positive electrode welding bottom plate 6 and the negative electrode welding bottom plate 5 and the cover plate 1, the insulation between the positive electrode welding bottom plate 6 and the negative electrode welding bottom plate 5 and the cover plate 1 is ensured through the plastic part 7. Since through holes corresponding to the through holes 101 are formed in the plastic part 7, the negative electrode tab 2 and the positive electrode tab 3 can pass through the through holes of the plastic part 7 and pass out through the through holes 101.

[0073] Specifically, the size and position of the through holes can be adapted to the size and position of the through holes 101. In the embodiments of the present application, the shape of the through holes is not specifically limited.

[0074] The installation process of the battery cell in this embodiment is described as follows:

[0075] First, an insulating film is wrapped around the outer surface of the electrode assembly 9, and then the electrode assembly 9 is inserted into the accommodating cavity of the housing 8 from the opening of the housing 8.

[0076] The cover plate 1 is arranged on the opening of the housing 8. Since two through holes 101 are formed in the cover plate 1 and the positions of the two through holes 101 correspond to those of the negative electrode tab 2 and the positive electrode tab 3, the negative electrode tab 2 and the positive electrode tab 3 on the electrode assembly 9 respectively pass through the two through holes 101 on the cover plate 1. Installers can bend the negative electrode tab 2 and the positive electrode tab through the through holes 101, so that the negative electrode tab 2 and the positive electrode welding tab respectively abut against the negative electrode welding bottom plate 5 and the positive electrode welding bottom plate 6. Installers can also weld and fix the negative electrode welding bottom plate 5 and the negative electrode tab 2, and the positive electrode welding bottom plate 6 and the positive electrode tab 3 through the through holes 101.

[0077] Finally, the sealing plate 4 is arranged at the through holes 101, abuts against the bottom surface of the sealing plate 4 through the step surface, and welds the side wall of the sealing plate 4 and the inner wall of the first groove section 10111 to ensure close contact between the sealing plate 4 and the through holes 101, thus completing the assembly of the battery cell.

[0078] According to an embodiment of the present invention, on the other hand, a battery pack is further provided, which includes a plurality of battery cells.

[0079] This battery pack includes the battery cell as described above and has all the beneficial technical effects of the battery cell, which will not be elaborated here.

[0080] Although the embodiments of the present invention are described with reference to 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 all fall within the scope defined by the appended claims.

Claims

1. A battery cell, characterized in that, Comprising: A cover plate, having two through holes spaced apart along the length direction, each of the through holes being provided with a stepped groove disposed around the inner wall of the through hole, the stepped groove including a first groove section and a second groove section arranged vertically, the size of the first groove section being larger than that of the second groove section and a stepped surface being formed at the connection between the first groove section and the second groove section; A sealing plate, covering the through hole in one-to-one correspondence, the bottom surface of the sealing plate abutting against the stepped surface, and the side wall of the sealing plate being welded to the inner wall of the first groove section.

2. The battery cell according to claim 1, characterized in that, The thickness of the sealing plate is less than the groove depth of the first groove section.

3. The battery cell according to claim 2, wherein, The thickness of the sealing plate is 0.2 mm to 0.4 mm less than the groove depth of the first groove section.

4. The cell according to claim 1, wherein, The groove depth of the first groove section is t, and the thickness of the cover plate is T, where 0.25T ≤ t ≤ 0.8T.

5. The cell according to claim 1, wherein Around the top of the inner wall of each through hole, a first chamfer is provided, and around the bottom of the side wall of each sealing plate, a second chamfer is provided.

6. The battery cell according to claim 1, characterized in that, It further includes an electrode group, the end of the electrode group being provided with a negative electrode tab and a positive electrode tab, the sealing plate including a cover body and a plastic plate, the plastic plate being disposed on one side of the cover body and located between the negative electrode tab and the positive electrode tab and the cover body.

7. The battery cell according to claim 6, characterized in that The bottom surface of the cover body abuts against the stepped surface.

8. The battery cell according to any one of claims 1, 2, or 4 to 6, characterized in that It further includes a negative electrode welding bottom plate and a positive electrode welding bottom plate, the negative electrode welding bottom plate and the positive electrode welding bottom plate being disposed below the cover plate, and the negative electrode welding bottom plate and the positive electrode welding bottom plate respectively extending to the corresponding through holes.

9. The battery cell according to claim 8, wherein, It further includes a plastic part, the plastic part being disposed between the negative electrode welding bottom plate and the positive electrode welding bottom plate and the cover plate, and the plastic part being provided with a through hole corresponding to the through hole.

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

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