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 shell, two ends of the shell are provided with an opening and a cover plate for sealing the opening, and the cover plate is provided with a pole mounting hole; each pole comprises a main body part and an annular part positioned on one side of the main body part, and the annular parts are arranged in the pole mounting holes in a penetrating manner; the pole group is arranged in the shell, and tabs are arranged at two ends of the pole group; and the pair of connecting sheets are arranged in the shell and are respectively arranged at the two ends of the pole group, the connecting sheets are provided with convex parts, and the convex parts are arranged in the pole mounting holes in a penetrating manner and are connected with the lower surface of the annular part. In the assembling process, the relative position of the connecting piece and the pole can be quickly and accurately positioned only by inserting the annular part and the convex part into the pole mounting hole, so that the time consumed in the assembling process is shortened, and the production efficiency of subsequent battery cells 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 connecting piece in the battery cell is a metal piece used to connect the pole post of the battery cell and the tab of the electrode group. It ensures the smooth flow of current between the pole post and the tab, and realizes the storage and release of electrical energy of the battery cell. However, currently, directly connecting the connecting piece to the pole post makes it difficult to install the two accurately in a short time. During the process of adjusting the positioning of the two, the assembly time of the battery cell is bound to be prolonged, reducing the production efficiency of the battery cell. Summary of the Utility Model

[0003] In view of this, the utility model provides a battery cell and a battery pack to solve the problems in the related art that it is difficult to accurately position the connecting piece and the pole post, and the assembly time is long, affecting the production efficiency of the battery cell.

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

[0005] A housing with openings at both ends and a cover plate for sealing the openings, and the cover plate is provided with pole post mounting holes;

[0006] A pair of pole posts, each comprising a main body portion and an annular portion located on one side of the main body portion, and the annular portion is inserted through the pole post mounting hole;

[0007] An electrode group disposed in the housing and having tabs at both ends;

[0008] A pair of connecting pieces disposed in the housing and respectively disposed at both ends of the electrode group, the connecting piece is formed with a convex portion, and the convex portion is inserted through the pole post mounting hole and connected to the lower surface of the annular portion.

[0009] Advantageous Effects: By providing an opening communicating with the inside on the housing, the utility model facilitates the operator to assemble relevant structures such as the electrode group into the housing, improving the convenience of assembly. Further, using the cover plate to seal the opening ensures the sealing performance of the battery cell, reduces the possibility of external moisture, dust and other impurities entering the interior of the battery cell, guarantees the cleanliness and stability of the internal environment of the battery cell, and thus is beneficial to extending the service life of the battery cell. In addition, since the annular portion and the convex portion in the utility model need to be inserted into the pole post mounting hole, during the assembly of the battery cell, the operator can quickly and accurately position the relative positions of the connecting piece and the pole post. In this way, the time consumed during the assembly process can be reduced, and the production efficiency of the subsequent battery cell can be improved.

[0010] In an alternative embodiment, the annular portion extends along the axial direction of the main body portion, and the diameter of the annular portion is smaller than the diameter of the main body portion.

[0011] Advantages: In the present utility model, the annular portion extends along the axial direction of the main body portion. On the one hand, it can reduce the complexity of the production process of the pole column and improve production efficiency; on the other hand, it can also reduce the assembly difficulty between the pole column and the cover plate and improve assembly efficiency. Secondly, making the diameter of the annular portion smaller than the diameter of the main body portion allows the annular portion to play a role in positioning and guiding during the assembly process, shortening the time consumed for installing and positioning the pole column and the pole column installation hole. In addition, compared with the case where the diameter of the annular portion is adapted to the diameter of the main body portion, the diameter of the annular portion being smaller than the diameter of the main body portion reduces the amount of pole column material used and optimizes the self-weight of the pole column.

[0012] In an alternative embodiment, the annular portion and the protruding portion are adapted to the shape of the pole column installation hole.

[0013] Advantages: In the present utility model, making the annular portion and the protruding portion adapted to the shape of the pole column installation hole can prevent the annular portion and the protruding portion in the connected state from moving relative to the pole column installation hole, ensuring the structural stability and use safety of the battery cell.

[0014] In an alternative embodiment, a cavity is provided inside the protruding portion, and the protruding portion and the annular portion are connected by laser welding.

[0015] Advantages: In the present utility model, the inside of the protruding portion is set to be hollow, which can reduce the amount of material used. In this way, not only can the production cost be reduced, but also it is beneficial to reduce the weight of the battery cell, meeting the development requirements of the lightweight of the battery cell. Secondly, connecting the protruding portion and the annular portion by welding can not only enhance the connection strength between the pole ear and the connecting piece, but also reduce the resistance at the connection between the two, optimize the current conduction path, and improve the performance of the battery cell during charging and discharging.

[0016] In an alternative embodiment, it further includes a sealing ring, a plastic ring and a plastic plate. The sealing ring is sleeved outside the annular portion and abuts against the hole wall of the pole column installation hole; the plastic ring is sleeved outside the main body portion and the lower surface thereof is attached to the upper surface of the cover plate; the plastic plate is sleeved outside the annular portion and is located between the cover plate and the connecting piece.

[0017] Beneficial effects: By providing a sealing ring, a plastic ring, and a plastic plate, the present utility model can seal the gap between the pole post and the pole post mounting hole, preventing the electrolyte inside the battery cell from leaking out through the above-mentioned gap. Secondly, since the cover plate is usually made of a metal conductive material, using a plastic ring can keep the cover plate and the pole post in an insulated and isolated state at all times. Similarly, using a plastic plate can keep the cover plate and the connecting piece in an insulated and isolated state at all times, thus ensuring the safety of the battery cell during use. In addition, since part of the structures of the plastic ring and the plastic plate and the sealing ring are located between the main body part and the connecting piece, the sealing ring, the plastic ring, and the plastic plate can be firmly fixed on the cover plate through the limiting cooperation between the main body part and the connecting piece.

[0018] In an alternative embodiment, a welding through-hole is provided on one of the cover plates, and a liquid injection hole and an explosion-proof valve are provided on the other cover plate.

[0019] Beneficial effects: By arranging the liquid injection hole and the explosion-proof valve on the cover plate, on the one hand, the self-structure of the cover plate can be made more compact, optimizing the structural layout on the cover plate; on the other hand, it is convenient to add electrolyte into the battery cell, and at the same time, it can prevent the pressure inside the battery cell from being too high, improving the safety of the battery cell during use. In addition, by providing a welding through-hole on the cover plate, the present utility model can provide an operating space for the operator to quickly connect the pole ear and the connecting piece, improving the convenience of operation.

[0020] In an alternative embodiment, the pole ear and the corresponding pole post are arranged in a staggered manner along the length direction of the housing. One of the pole ears includes a body connected to the pole group and a bent portion bent from the end of the body toward one side. The bent portion is arranged corresponding to the welding through-hole. One of the connecting pieces is fixed in the space defined by the body and the bent portion and is attached to the lower surface of the bent portion.

[0021] Beneficial effects: The pole post and the pole ear of the present utility model are arranged in a staggered manner, making use of the space in the housing along the length direction. Compared with the existing connecting piece and pole ear both arranged along the axial direction of the pole post, the internal space of the housing occupied by the connecting piece and the pole ear in the connected state in the height direction (axial direction of the pole post) of the housing is reduced, improving the utilization rate of the internal space of the housing. Furthermore, the pole ear is connected to the connecting piece through the bent portion, which can reduce the operation difficulty of connecting the pole ear and the connecting piece and also reduce the occupation of the internal space of the housing in the connected state of the two.

[0022] In an alternative embodiment, the connecting piece includes a pole post connecting portion connected to the pole post and a pole ear connecting portion connected to the pole ear, and the positioning post is located on the pole post connecting portion.

[0023] Beneficial effect: Since the pole lug and pole post in the utility model are staggered, the connecting piece is divided into a pole post connecting part and a pole lug connecting part, so that the connecting piece can be adapted to the position of the pole lug and the pole post, so that the pole lug and the pole post can be connected, realizing smooth flow of current between the pole lug and the pole post.

[0024] In an optional embodiment, a gap is left between the tab connection portion and the inner wall of the shell extending along the length direction thereof, and the bending portion is arranged on the upper surface of the tab connection portion through the body, through the gap and the welding through hole.

[0025] Beneficial effect: Since the lower surface of the bent portion needs to fit with the upper surface of the tab connection portion, if the bent portion is to come to the upper surface of the tab connection portion, it is usually necessary to set a passage opening suitable for the body to pass through on the tab connection portion. However, this will make the structure of the tab connection portion relatively complicated and increase the initial production cost. Therefore, in order to solve the above problem, the utility model allows the body to pass through the gap between the tab connection portion and the inner wall of the shell extending along its length direction and the welding through hole on the cover plate, which can simplify the structure of the connecting piece without making complex adjustments to the structure of the connecting piece.

[0026] In a second aspect, the utility model further provides a battery pack, comprising:

[0027] A plurality of the above-mentioned battery cells.

[0028] Beneficial effect: Since the connecting piece in the above-mentioned battery cell is positioned and connected with the pole through the pole mounting hole on the cover plate, the battery pack of the utility model can shorten its assembly time and improve its production efficiency after adopting the above-mentioned battery cell. In addition, the battery pack of the utility model has all the advantages of the above-mentioned battery cell, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 It is a partial structural schematic diagram of a battery cell according to an embodiment of the utility model;

[0031] Figure 2 A partial structural schematic diagram of another battery cell according to an embodiment of the utility model;

[0032] Figure 3A cross-sectional schematic view of a cover plate according to an embodiment of the present utility model;

[0033] Figure 4 is Figure 3 a partially enlarged view of A in;

[0034] Figure 5 A bottom view schematic diagram of another cover plate according to an embodiment of the present utility model;

[0035] Figure 6 A structural schematic diagram of a connecting piece according to an embodiment of the present utility model;

[0036] Figure 7 is Figure 6 a cross-sectional schematic view of the connecting piece shown;

[0037] Figure 8 A structural schematic diagram of yet another cover plate according to an embodiment of the present utility model;

[0038] Figure 9 is Figure 8 a cross-sectional schematic view of the cover plate shown;

[0039] Figure 10 is Figure 8 a bottom view schematic diagram of the cover plate shown.

[0040] Explanation of reference numerals:

[0041] 1. Housing; 101. Cover plate; 1011. Welding through hole; 1012. Liquid injection hole; 1013. Explosion-proof valve; 1014. Sealing plate; 2. Terminal; 201. Main body part; 202. Annular part; 3. Tab; 4. Connecting piece; 401. Protrusion part; 4011. Cavity; 402. Terminal connecting part; 403. Tab connecting part; 5. Sealing ring; 6. Plastic ring; 7. Plastic plate. Detailed implementation manners

[0042] 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 in conjunction with 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 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.

[0043] In view of the problems in the related art that it is difficult to accurately position the connecting piece and the terminal, and the assembly time is relatively long, which affects the production efficiency of the battery cell, the present utility model provides a battery cell and a battery pack.

[0044] The following combines Figures 1 to 10 , to describe the embodiments of the present utility model.

[0045] According to an embodiment of the present utility model, on the one hand, as Figures 1 to 4 shown, a battery cell is provided, including: a housing 1, a pair of pole columns 2, a pole group, and a pair of connection pieces 4.

[0046] Specifically, openings are provided at both ends of the housing 1 and a cover plate 101 for sealing the openings, and the cover plate 101 is provided with pole column mounting holes; a pair of pole columns 2 each include a main body portion 201 and an annular portion 202 located on one side of the main body portion 201, and the annular portion 202 is inserted through the pole column mounting holes; the pole group is disposed inside the housing 1 and pole tabs 3 are provided at both ends; a pair of connection pieces 4 are disposed inside the housing 1 and are respectively disposed at both ends of the pole group, and the connection piece 4 is formed with a protruding portion 401, and the protruding portion 401 is inserted through the pole column mounting hole and connected to the lower surface of the annular portion 202.

[0047] In this embodiment, by providing an opening on the housing 1 that communicates with its interior, it is convenient for operators to assemble relevant structures such as the pole group into the housing 1, improving the convenience of assembly. Further, the cover plate 101 is used to seal the opening, ensuring the sealing performance of the battery cell, reducing the possibility of external moisture, dust and other impurities entering the interior of the battery cell, ensuring the cleanliness and stability of the internal environment of the battery cell, and thus being beneficial to extending the service life of the battery cell. In addition, since the annular portion 202 and the protruding portion 401 in this embodiment need to be inserted into the pole column mounting holes, when assembling the battery cell, operators can quickly and accurately position the relative positions of the connection piece 4 and the pole column 2, and in this way, the time consumed in the assembly process can be reduced, improving the production efficiency of the subsequent battery cell.

[0048] It should be noted that the lower surface of the annular portion 202 in this embodiment refers to the side of the annular portion 202 facing the connection piece 4.

[0049] According to an embodiment of the present utility model, as Figure 3 and Figure 4 shown, the annular portion 202 extends along the axial direction of the main body portion 201, and the diameter of the annular portion 202 is smaller than the diameter of the main body portion 201. In this embodiment, making the annular portion 202 extend along the axial direction of the main body portion 201 can, on the one hand, reduce the complexity of the production process of the pole column 2 and improve the production efficiency; on the other hand, it can also reduce the assembly difficulty between the pole column 2 and the cover plate 101 and improve the assembly efficiency. Secondly, making the diameter of the annular portion 202 smaller than the diameter of the main body portion 201 can enable the annular portion 202 to play a role of positioning and guiding during the assembly process, shortening the time consumed for the installation and positioning of the pole column 2 and the pole column mounting hole. In addition, compared with the diameter of the annular portion 202 being adapted to the diameter of the main body portion 201, the diameter of the annular portion 202 being smaller than the diameter of the main body portion 201 reduces the amount of material used for the pole column 2 and optimizes the self-weight of the pole column 2.

[0050] According to an embodiment of the present utility model, as shown in Figure 3 and Figure 4 shown, the annular portion 202 and the convex portion 401 are adapted to the shape of the pole post mounting hole. In this embodiment, the annular portion 202 and the convex portion 401 are adapted to the shape of the pole post mounting hole, which can prevent the annular portion 202 and the convex portion 401 in the connected state from moving relative to the pole post mounting hole, ensuring the structural stability and use safety of the battery cell.

[0051] According to an embodiment of the present utility model, as shown in Figure 6 and Figure 7 shown, a cavity 4011 is provided inside the convex portion 401, and the convex portion 401 and the annular portion 202 are connected by laser welding. In this embodiment, the inside of the convex portion 401 is set to be hollow, which can reduce the amount of material used. In this way, not only can the production cost be reduced, but also the weight of the battery cell can be reduced, meeting the lightweight development requirements of the battery cell. Secondly, by connecting the convex portion 401 and the annular portion 202 by welding, not only can the connection strength between the pole ear 3 and the connecting piece 4 be enhanced, but also the resistance at the connection between the two can be reduced, optimizing the current conduction path and improving the charge and discharge performance of the battery cell.

[0052] According to an embodiment of the present utility model, as shown in Figure 4 shown, it further includes a sealing ring 5, a plastic ring 6 and a plastic plate 7. The sealing ring 5 is sleeved outside the annular portion 202 and abuts against the hole wall of the pole post mounting hole; the plastic ring 6 is sleeved outside the main body portion 201 and its lower surface is attached to the upper surface of the cover plate 101; the plastic plate 7 is sleeved outside the annular portion 202 and is located between the cover plate 101 and the connecting piece 4. In this embodiment, by providing the sealing ring 5, the plastic ring 6 and the plastic plate 7, the gap between the pole post 2 and the pole post mounting hole can be sealed to prevent the electrolyte inside the battery cell from overflowing from the above-mentioned gap. Secondly, since the material of the cover plate 101 is usually a metal conductive material, the use of the plastic ring 6 can keep the cover plate 101 and the pole post 2 in an insulated and isolated state. Similarly, by using the plastic plate 7, the cover plate 101 and the connecting piece 4 can be kept in an insulated and isolated state all the time, thus ensuring the use safety of the battery cell. In addition, since part of the structures of the plastic ring 6 and the plastic plate 7 and the sealing ring 5 are located between the main body portion 201 and the connecting piece 4, the sealing ring 5, the plastic ring 6 and the plastic plate 7 can be firmly fixed on the cover plate 101 through the limit cooperation of the main body portion 201 and the connecting piece 4.

[0053] It should be noted that in this embodiment, the lower surface of the plastic ring 6 refers to the side of the plastic ring 6 close to the cover plate 101; the upper surface of the cover plate 101 refers to the side of the cover plate 101 away from the electrode group.

[0054] According to an embodiment of the present utility model, as shown inFigure 3 , Figure 8 , Figure 9 and Figure 10 As shown, a welding through-hole 1011 is provided on one cover plate 101, and a liquid injection hole 1012 and an explosion-proof valve 1013 are provided on the other cover plate 101. In this embodiment, the liquid injection hole 1012 and the explosion-proof valve 1013 are arranged on the cover plate 101. On the one hand, the self-structure of the cover plate 101 can be made more compact, and the structural layout on the cover plate 101 can be optimized; on the other hand, it is convenient to add electrolyte into the battery cell, and at the same time, the pressure inside the battery cell can be prevented from being too high, improving the use safety of the battery cell. In addition, in this embodiment, by providing the welding through-hole 1011 on the cover plate 101, an operating space can be left for the operator to quickly connect the tab 3 and the connecting piece 4, improving the convenience of operation.

[0055] In order to ensure the sealing performance of the housing 1, in a specific embodiment, as Figure 3 shown, a sealing plate 1014 is provided on the cover plate 101, and the sealing plate 1014 is welded to the welding through-hole 1011 to seal the welding through-hole 1011.

[0056] According to an embodiment of the present invention, as Figure 1 shown, the tab 3 and the corresponding terminal 2 are arranged in a staggered manner along the length direction of the housing 1. One of the tabs 3 includes a body connected to the electrode group and a bent portion bent from the end of the body toward one side. The bent portion is arranged corresponding to the welding through-hole 1011. One of the connecting pieces 4 is fixed in the space defined by the body and the bent portion and is attached to the lower surface of the bent portion. In this embodiment, the terminal 2 and the tab 3 are arranged in a staggered manner, making use of the space in the length direction inside the housing 1. Compared with the existing connecting piece 4 and tab 3 both arranged along the axial direction of the terminal 2, the internal space of the housing 1 occupied by the connecting piece 4 and the tab 3 in the height direction (axial direction of the terminal) of the housing 1 in the connected state is reduced, improving the utilization rate of the internal space of the housing 1. Furthermore, the tab 3 is connected to the connecting piece 4 through the bent portion, which can reduce the operation difficulty of connecting the tab 3 and the connecting piece 4 and also reduce the occupation of the internal space of the housing 1 when they are in the connected state.

[0057] It should be noted that the above-mentioned length direction of the housing 1 is consistent with Figure 1 and Figure 2 the directions shown in.

[0058] According to an embodiment of the present invention, as Figure 5 and Figure 6As shown, the connecting piece 4 includes a pole connecting portion 402 connected to the pole 2 and a pole lug connecting portion 403 connected to the pole lug 3, and the positioning column is located on the pole connecting portion 402. Since the pole lug 3 and the pole 2 in this embodiment are staggered, the connecting piece 4 is divided into the pole connecting portion 402 and the pole lug connecting portion 403, so that the connecting piece 4 can be adapted to the position of the pole lug 3 and the pole 2, so that the pole lug 3 and the pole 2 can be connected, and the current can flow smoothly between the pole lug 3 and the pole 2.

[0059] It should be noted that the height direction of the housing 1 is Figure 1 and Figure 2 The direction shown in is consistent.

[0060] According to an embodiment of the utility model, a gap is left between the tab connection part 403 and the inner wall of the shell 1 extending in the length direction, and the bent portion is arranged on the upper surface of the tab connection part 403 through the gap through the body. Since the lower surface of the bent portion needs to fit with the upper surface of the tab connection part 403, if the bent portion is to come to the upper surface of the tab connection part 403, it is usually necessary to set a passage opening suitable for the body to pass through on the tab connection part 403, however, this will make the structure of the tab connection part 403 relatively complicated, increasing the initial production cost. Therefore, in order to solve the above problem, this embodiment allows the body to pass through the tab connection part 403 and leave a gap between the inner wall of the shell 1 extending in the length direction, so that there is no need to make complex adjustments to the structure of the connecting piece 4, simplifying the structure of the connecting piece 4.

[0061] It should be noted that, in this embodiment, the lower surface of the bent portion refers to the side of the bent portion facing the connecting sheet 4 , and the upper surface of the pole lug connecting portion 403 is the side of the connecting sheet 4 away from the pole group.

[0062] According to an embodiment of the present invention, on the other hand, a battery pack is also provided, comprising: a plurality of the above-mentioned battery cells. Since the connecting piece 4 in the above-mentioned battery cell is positioned and connected with the pole 2 through the pole mounting hole on the cover plate 101, the battery pack of this embodiment can shorten its own assembly time and improve its own production efficiency after adopting the above-mentioned battery cell. In addition, the battery pack of the present invention has all the advantages of the above-mentioned battery cell, which will not be repeated here.

[0063] It should be noted that the battery cells in this embodiment include but are not limited to lithium-ion battery cells. Multiple battery cells can be grouped and electrically connected through a bus bar to form multiple battery cell modules, and multiple battery cell modules form a battery pack.

[0064] In addition, to implement the basic functions of the battery pack, the battery pack in this embodiment may further include other necessary modules or components, such as a battery management system, a heat dissipation system, etc. It should be noted that for the other necessary modules or components included in the battery pack, any suitable existing structure can be selected. To clearly and briefly illustrate the technical solution provided in this embodiment, the above parts will not be elaborated herein, and the accompanying drawings of the specification have also been correspondingly simplified. However, it should be understood that the scope of the present utility model is not limited thereby.

[0065] Although the 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 all fall within the scope defined by the appended claims.

Claims

1. A battery cell, characterized in that: include: The shell has openings and cover plates sealing the openings at both ends, and the cover plates are provided with pole mounting holes; A pair of poles, each comprising a main body and an annular portion located on one side of the main body, wherein the annular portion is inserted into the pole mounting hole; A pole group is arranged in the shell and has pole ears at both ends; A pair of connecting pieces are arranged in the shell and respectively arranged at two ends of the pole group. The connecting pieces are formed with protrusions, which are passed through the pole mounting holes and connected to the lower surface of the annular portion.

2. The battery cell according to claim 1, characterized in that: The annular portion extends along the axial direction of the main body portion, and a diameter of the annular portion is smaller than a diameter of the main body portion.

3. The battery cell according to claim 1, characterized in that: The annular portion and the protruding portion are adapted to the shape of the pole mounting hole.

4. The battery cell according to claim 1, characterized in that: A cavity is provided inside the raised portion, and the raised portion is connected to the annular portion by laser welding.

5. The battery cell according to claim 1, characterized in that: It also includes a sealing ring, a plastic ring and a plastic plate. The sealing ring is sleeved outside the annular portion and abuts against the hole wall of the pole mounting hole; the plastic ring is sleeved outside the main body and the lower surface is in contact with the upper surface of the cover plate; the plastic plate is sleeved outside the annular portion and is located between the cover plate and the connecting piece.

6. The battery cell according to any one of claims 1 to 5, characterized in that: One of the cover plates is provided with a welding through hole, and the other cover plate is provided with a liquid injection hole and an explosion-proof valve.

7. The battery cell according to claim 6, characterized in that: The pole ears and the corresponding pole posts are staggered along the length direction of the shell, one of the pole ears includes a main body connected to the pole group and a bent portion bent from the end of the main body toward one side, the bent portion is arranged corresponding to the welding through hole, and one of the connecting sheets is fixed in the space defined by the main body and the bent portion and fits with the lower surface of the bent portion.

8. The battery cell according to claim 7, characterized in that: The connecting piece includes a pole connecting portion connected to the pole and a pole lug connecting portion connected to the pole lug, and the protrusion is located on the pole connecting portion.

9. The battery cell according to claim 8, characterized in that: A gap is left between the tab connection portion and the inner wall of the shell extending along the length direction thereof, and the bent portion passes through the body, through the gap and the welding through hole, and is arranged on the upper surface of the tab connection portion.

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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