Battery cell and battery pack

Abstract

The utility model relates to the technical field of batteries, and discloses a battery cell and a battery pack. The battery cell comprises: a housing, which is provided with a cavity and an opening communicated with the cavity; the cover plate is arranged on the opening and seals the cavity, a pole is arranged on the cover plate, and one end of the pole is located in the cavity; the pole group is arranged in the cavity and is provided with a pole lug, the pole lug and the pole column are arranged in a staggered manner, and the pole lug comprises a body connected with the pole group and a bending part which is bent towards one side from the end part of the body; the connecting sheet is arranged in the cavity, is positioned on the pole group, is used for connecting the pole column and the pole lug, is fixed in a space defined by the body and the bending part, and is attached to the lower surface of the bending part; the anti-explosion valve is arranged on the side, away from the opening, of the shell. The tabs are connected with the connecting pieces through the bending parts, so that the operation difficulty of connection between the tabs and the connecting pieces can be reduced, and the occupation of the tabs and the connecting pieces on the internal space of the shell in the connection state is reduced. And secondly, the anti-explosion valve is far away from the pole, so that the pole can be prevented from being damaged in the pressure relief process.

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 column of the battery cell and the ear of the pole group. It ensures the smooth flow of current between the pole column and the ear, and realizes the storage and release of electric energy of the battery cell. However, the method of connecting the connecting piece and the ear adopted in the related art is not only complicated to operate, but also occupies a relatively large internal space of the battery cell.

[0003] In addition, in order to improve the use safety of electricity, an explosion-proof valve is generally provided on the battery cell to ensure that the excessive pressure inside the battery cell can be released in time. However, when the explosion-proof valve relieves pressure, the released pressure may damage the pole column, affecting the use safety of the battery cell. Content of the Utility Model

[0004] In view of this, the utility model provides a battery cell and a battery pack to solve the following two problems:

[0005] Problem 1: The problem that the connection method between the connecting piece and the ear in the related art is complicated and occupies a relatively large internal space of the battery cell;

[0006] Problem 2: The problem that the explosion-proof valve in the related art may damage the pole column when relieving pressure.

[0007] In the first aspect, the utility model provides a battery cell, comprising:

[0008] A housing, provided with a cavity and an opening communicating with the cavity;

[0009] A cover plate, arranged on the opening and sealing the cavity. A pole column is arranged on the cover plate, and one end of the pole column is located inside the cavity;

[0010] A pole group, arranged inside the cavity and provided with an ear. The ear is arranged in a dislocation manner with the pole column. The ear comprises a body connected to the pole group and a bent part bent from the end of the body towards one side;

[0011] A connecting piece, arranged inside the cavity and located on the pole group, used to connect the pole column and the ear. The connecting piece is fixed in the space defined by the body and the bent part and is attached to the lower surface of the bent part;

[0012] An explosion-proof valve, arranged on the side of the housing away from the opening.

[0013] Advantageous effects: By providing an opening on the housing that communicates with its cavity, it is convenient for operators 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 conducive to extending the service life of the battery cell. Secondly, the pole column and the pole ear of the present utility model are arranged in a dislocation manner, making use of the space in the length direction inside the housing. Compared with the existing connection piece and pole ear both arranged along the axial direction of the pole column, the internal space of the housing occupied in the height direction of the housing when the connection piece and the pole ear are in a connected state is reduced, improving the utilization rate of the internal space of the housing. Furthermore, more energy can be stored in the battery cell of the same volume. Moreover, the pole ear is connected to the connection piece through a bending portion, which can reduce the operation difficulty of connecting the pole ear and the connection piece and also reduce the occupation of the internal space of the housing when the two are in a connected state. In addition, the explosion-proof valve is arranged on one side of the housing far away from the opening. On the one hand, it can reduce the occupation of the space on the cover plate and optimize the layout. On the other hand, compared with arranging the explosion-proof valve on the cover plate, it can reduce the possibility of damaging the structure (such as the pole column) on the cover plate during the pressure relief process of the explosion-proof valve.

[0014] In an alternative embodiment, a pair of the pole columns are arranged at intervals along the length direction of the cover plate, and a through hole is arranged between the pair of the pole columns. The through hole is arranged on the cover plate and communicates with the cavity.

[0015] Advantageous effects: Since the pole columns on the cover plate are divided into a positive pole column and a negative pole column, the present utility model arranges a pair of pole columns at intervals along the length direction of the cover plate, which can increase the physical distance between the positive pole column and the negative pole column and reduce the probability of short circuit between the positive pole column and the negative pole column. Secondly, arranging the through hole between the pair of pole columns and connecting the through hole with the cavity of the housing can leave an operation space for the operator to quickly connect the pole ear and the connection piece, improving the convenience of operation. Moreover, only one through hole is arranged on the cover plate, reducing the number of openings on the cover plate and lowering the complexity of the preparation process of the cover plate.

[0016] In an alternative embodiment, a sealing plate is arranged on the cover plate. The sealing plate seals the through hole and a liquid injection hole is arranged on the sealing plate.

[0017] Advantageous effects: The present utility model seals the through hole on the cover plate by using the sealing plate, which can improve the sealing performance of the battery cell and reduce the possibility of external impurities entering the interior of the battery cell. Secondly, arranging the liquid injection hole on the sealing plate can make the self-structure of the cover plate more compact and optimize the structural layout on the cover plate.

[0018] In an alternative embodiment, the through-hole is rectangular in shape and the length direction of the through-hole is consistent with the length direction of the cover plate.

[0019] Advantageous effects: In the present utility model, the through-hole is rectangular in shape and the length direction of the through-hole is consistent with the length direction of the cover plate. On the one hand, it can provide a larger operating space for the operator, making the connection operation between the tab and the connecting piece simpler and more convenient; on the other hand, it enables the operator to judge the assembly direction of the cover plate on the housing in a short time, improving the assembly efficiency and reducing the time consumed for assembly.

[0020] In an alternative embodiment, the connecting piece includes a pole connecting portion connected to the pole and a tab connecting portion connected to the tab. A transition connecting portion is formed between the tab connecting portion and the pole connecting portion, and the position of the through-hole corresponds to the position of the tab connecting portion.

[0021] Advantageous effects: Since the tabs and poles in the present utility model are arranged in a staggered manner, the connecting piece is divided into a pole connecting portion and a tab connecting portion, which can make the connecting piece adapt to the positions of the tab and the pole, so that the tab and the pole can be connected, realizing the smooth flow of current between the tab and the pole. In addition, by forming a transition connecting portion between the tab connecting portion and the pole connecting portion, the stress concentration phenomenon between the tab connecting portion and the pole connecting portion can be avoided, ensuring the connection strength between the two.

[0022] In an alternative embodiment, a pair of the connecting pieces are arranged at intervals along the length direction of the pole group. The tabs are respectively arranged on the opposite sides of each connecting piece. The tabs on the opposite sides are respectively located on the opposite sides of the tab connecting portion along the width direction of the pole group, and their respective bending portions are bent and extended towards each other.

[0023] Advantageous effects: Since the poles on the cover plate are divided into a positive pole and a negative pole, and the tabs on the pole group are divided into a positive tab and a negative tab, by arranging a pair of connecting pieces on the pole group, not only can the positive pole and the positive tab be connected, but also the negative pole and the negative tab can be connected. In this way, the stable transmission of current between the tab and the pole can be ensured, reducing the problem of poor contact. Secondly, arranging the pair of connecting pieces at intervals can avoid the short-circuit between the positive pole and the negative pole, improving the safety of the battery cell during use. Moreover, making the tabs on the opposite sides be respectively located on the opposite sides of the tab connecting portion along the width direction of the pole group makes the internal structure of the battery cell more compact, thus improving the space utilization rate inside the housing.

[0024] In an alternative embodiment, a gap is left between the ends of the bending portions on the opposite sides that are close to each other.

[0025] Beneficial effects: Compared with stacking the bent portions of two tab ears on one connecting piece, the present utility model leaves a gap between the ends of the bent portions on opposite sides that are close to each other, which can reduce the thickness when the two tab ears are connected to one connecting piece, that is, reduce the occupation of the internal space of the housing and improve the energy density of the battery cell.

[0026] In an optional embodiment, a notch extending along the length direction of the pole group is provided on the tab ear connecting portion, and the notch divides the tab ear connecting portion into two sub-connecting portions. The two sub-connecting portions correspond to a pair of tab ears one by one and are respectively welded to the lower surface of the corresponding bent portion.

[0027] Beneficial effects: Since the welding method of the bent portion and the connecting piece can adopt ultrasonic welding, compared with taking the tab ear connecting portion as a whole, the present utility model uses the notch to divide the tab ear connecting portion into two sub-connecting portions, which can avoid the influence of the vibration generated during the ultrasonic welding process on the entire tab ear connecting portion and ensure the stability and quality of the welding of each sub-connecting portion to the corresponding tab ear.

[0028] In an optional embodiment, the cover plate is welded to the housing.

[0029] Beneficial effects: The present utility model welds the cover plate and the housing. On the one hand, it can ensure the connection strength between the two; on the other hand, it can ensure the sealing effect at the connection between the two, reduce the risk of impurities entering the interior of the battery cell, and ensure the stability and safety of the battery cell.

[0030] Second aspect, the present utility model also provides a battery pack, including:

[0031] Multiple battery cells as described above.

[0032] Beneficial effects: The battery pack of the present utility model can improve its space utilization rate by adopting the above-mentioned battery cells, so that without changing its own volume, it can improve its energy density, extend its usage time or reduce the charging frequency. Secondly, the explosion-proof valve is arranged on the side of the housing far away from the opening. On the one hand, it can reduce the occupation of the space on the cover plate and optimize the layout; on the other hand, compared with arranging the explosion-proof valve on the cover plate, it can reduce the possibility of damaging the structure (such as the pole column) on the cover plate during the pressure relief process of the explosion-proof valve. In addition, the battery pack of the present utility model has all the advantages of the above-mentioned battery cells and will not be elaborated here. Description of the Drawings

[0033] To more clearly illustrate the specific embodiments of the present utility model or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0034] Figure 1 Schematic structural diagram of a battery cell according to an embodiment of the present utility model;

[0035] Figure 2 For Figure 1 Schematic cross-sectional view of the battery cell shown;

[0036] Figure 3 Schematic structural diagram of another battery cell according to an embodiment of the present utility model;

[0037] Figure 4 For Figure 3 Schematic structural diagram of the battery cell shown without the housing and the cover plate installed;

[0038] Figure 5 Schematic structural diagram of yet another battery cell according to an embodiment of the present utility model;

[0039] Figure 6 Schematic connection diagram of the tab and the connecting piece according to an embodiment of the present utility model;

[0040] Figure 7 Schematic structural diagram of a cover plate according to an embodiment of the present utility model;

[0041] Figure 8 For Figure 7 Cross-sectional view of

[0042] Explanation of reference numerals:

[0043] 1. Housing; 2. Cover plate; 201. Terminal; 202. Through hole; 203. Sealing plate; 3. Electrode assembly; 301. Tab; 3011. Body; 3012. Bent portion; 4. Connecting piece; 401. Terminal connecting portion; 402. Tab connecting portion; 4021. Notch; 4022. Sub-connecting portion; 403. Transition connecting portion; 5. Explosion-proof valve; 6. Liquid injection hole. Specific embodiments

[0044] To make the objectives, technical solutions, and advantages of the embodiments of the present utility model clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present utility model 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 belong to the scope of protection of the present utility model.

[0045] The following will describe the embodiments of the present utility model in conjunction with Figures 1 to 8 , to describe the embodiments of the present utility model.

[0046] According to an embodiment of the present utility model, on the one hand, as Figures 1 to 8 shown, a battery cell is provided, including: a housing 1, a cover plate 2, an electrode assembly 3, a connecting piece 4, and an explosion-proof valve 5.

[0047] Specifically, the housing 1 is provided with a cavity and an opening communicating with the cavity; the cover plate 2 is disposed on the opening and seals the cavity, and a terminal post 201 is provided on the cover plate 2, and one end of the terminal post 201 is located in the cavity; the electrode assembly 3 is disposed in the cavity and is provided with an electrode tab 301, the electrode tab 301 is arranged in a staggered manner with the terminal post 201, and the electrode tab 301 includes a body 3011 connected to the electrode assembly 3 and a bent portion 3012 bent from the end of the body 3011 toward one side; the connecting piece 4 is disposed in the cavity and on the electrode assembly 3 for connecting the terminal post 201 and the electrode tab 301, and the connecting piece 4 is fixed in the space defined by the body 3011 and the bent portion 3012 and is attached to the lower surface of the bent portion 3012; the explosion-proof valve 5 is disposed on the side of the housing 1 away from the opening.

[0048] In this embodiment, an opening communicating with the cavity of the housing 1 is provided on the housing 1, which facilitates the operator to assemble relevant structures such as the electrode group 3 into the housing 1 and improves the convenience of assembly. Further, the cover plate 2 is used to seal the opening, ensuring the tightness 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 conducive to extending the service life of the battery cell. Secondly, the pole post 201 and the pole ear 301 in this embodiment are arranged in a staggered manner, making use of the space in the length direction inside the housing 1. Compared with the existing connection piece 4 and the pole ear 301 both arranged along the axial direction of the pole post 201, the internal space of the housing 1 occupied by the connection piece 4 and the pole ear 301 in the height direction of the housing 1 in the connected state is reduced, improving the utilization rate of the internal space of the housing 1, and thus enabling the battery cell to store more energy under the same volume. Moreover, the pole ear 301 is connected to the connection piece 4 through the bending part 3012, which can reduce the operation difficulty of connecting the pole ear 301 and the connection piece 4 and also reduce the occupation of the internal space of the housing 1 by the two in the connected state. In addition, the explosion-proof valve 5 is arranged on one side of the housing 1 far away from the opening. On the one hand, it can reduce the occupation of the space on the cover plate 2 and optimize the layout; on the other hand, compared with arranging the explosion-proof valve 5 on the cover plate 2, it can reduce the possibility of damaging the structures (such as the pole post) on the cover plate 2 during the pressure relief process of the explosion-proof valve 5.

[0049] It should be noted that the width direction and the height direction of the housing 1 in this embodiment are consistent with the directions shown in Figure 1 . In addition, the battery cell in this embodiment can be, but is not limited to, a square battery. Further, in order to improve the tightness at the connection between the cover plate 2 and the housing 1, sealant can be provided at the connection between the two.

[0050] In order to improve the self-structural strength of the pole ear 301, as Figure 6 shown, in a specific embodiment, the main body 3011 and the bending part 3012 are integrally formed, and a transition fillet is provided at the connection between the main body 3011 and the bending part 3012. Similarly, in order to improve the structural strength between the pole ear 301 and the electrode group 3, the pole ear 301 and the electrode group 3 can also be integrally formed.

[0051] In order to make the structure of the connection piece 4 and the pole ear 301 more compact in the connected state and reduce the unnecessary occupation of the internal space of the housing 1. In a specific embodiment, as Figure 6 shown, the main body 3011 and the bending part 3012 are perpendicularly arranged, and the height of the main body 3011 is adapted to the thickness of the connection piece 4. It can be understood that this design can make the lower surface of the bending part 3012 closely fit on the connection piece 4, improving the transmission efficiency of the current between the pole ear 301 and the pole post 201.

[0052] According to an embodiment of the present invention, asFigures 1 to 3 As shown in the figure, a pair of pole columns 201 are arranged at intervals along the length direction of the cover plate 2. A through hole 202 is arranged between the pair of pole columns 201. The through hole 202 is arranged on the cover plate 2 and communicates with the cavity. It can be understood that since the pole columns 201 on the cover plate 2 are divided into a positive pole column and a negative pole column, in this embodiment, the pair of pole columns 201 are arranged at intervals along the length direction of the cover plate 2, which can increase the physical distance between the positive pole column and the negative pole column and reduce the probability of short circuit between the positive pole column and the negative pole column. Secondly, the through hole 202 is arranged between the pair of pole columns 201 and the through hole 202 is connected to the cavity of the housing 1, which can leave an operation space for the operator to quickly connect the pole ear 301 and the connecting piece 4, improving the convenience of operation. Moreover, only one through hole 202 is arranged on the cover plate 2, reducing the number of openings on the cover plate 2 and lowering the complexity of the manufacturing process of the cover plate 2.

[0053] It should be noted that in this embodiment, the length direction of the cover plate is the same as the length direction of the housing 1 and is consistent with the direction shown in Figure 1 .

[0054] According to an embodiment of the present invention, as Figure 1 shown, a sealing plate 203 is arranged on the cover plate 2. The sealing plate 203 seals the through hole 202 and a liquid injection hole 6 is arranged on the sealing plate 203. In this embodiment, by using the sealing plate 203 to seal the through hole 202 on the cover plate 2, the sealing performance of the battery cell can be improved and the possibility of external impurities entering the interior of the battery cell can be reduced. Secondly, arranging the liquid injection hole 6 on the sealing plate 203 can make the self-structure of the cover plate 2 more compact and optimize the structural layout on the cover plate 2.

[0055] According to an embodiment of the present invention, as Figure 1 shown, the shape of the through hole 202 is rectangular and the length direction of the through hole 202 is consistent with the length direction of the cover plate 2. In this embodiment, the shape of the through hole 202 is made rectangular and the length direction of the through hole 202 is consistent with the length direction of the cover plate 2. On the one hand, it can provide a larger operation space for the operator and make the connection operation between the pole ear 301 and the connecting piece 4 easier and more convenient; on the other hand, it can enable the operator to judge the assembly direction of the cover plate 2 on the housing 1 in a short time, improving the assembly efficiency and reducing the time consumed by the assembly.

[0056] According to an embodiment of the present invention, as Figure 4 and Figure 6As shown, the connecting piece 4 includes a pole connecting portion 401 connected to the pole 201 and an ear connecting portion 402 connected to the tab 301. A transition connecting portion 403 is formed between the ear connecting portion 402 and the pole connecting portion 401. The position of the through hole 202 corresponds to the position of the ear connecting portion 402. Since the tab 301 and the pole 201 in this embodiment are arranged in a staggered manner, the connecting piece 4 is divided into the pole connecting portion 401 and the ear connecting portion 402, which can adapt the position of the connecting piece 4 to the positions of the tab 301 and the pole 201, so that the tab 301 and the pole 201 can be connected, realizing the smooth flow of current between the tab 301 and the pole 201. In addition, by forming a transition connecting portion 403 between the ear connecting portion 402 and the pole connecting portion 401, the stress concentration phenomenon between the ear connecting portion 402 and the pole connecting portion 401 can be avoided, ensuring the connection strength between the two.

[0057] It should be noted that since the connection position of the tab 301 and the electrode group 3 is higher than other positions of the electrode group 3, the position of the ear connecting portion 402 on the electrode group 3 needs to be adjusted adaptively, that is, along the height direction of the housing 1, the position of the ear connecting portion 402 is higher than the position of the pole connecting portion 401.

[0058] According to an embodiment of the present invention, as Figure 6 shown, a pair of connecting pieces 4 are arranged at intervals along the length direction of the electrode group 3. Tabs 301 are respectively arranged on the opposite sides of each connecting piece 4. The tabs 301 on the opposite sides are respectively located on the opposite sides of the ear connecting portion 402 along the width direction of the electrode group 3, and their bent portions 3012 are bent and extended towards each other. Since the poles 201 on the cover plate 2 are divided into positive poles and negative poles, and the tabs 301 on the electrode group 3 are divided into positive tabs and negative tabs, by arranging a pair of connecting pieces 4 on the electrode group 3, not only can the positive pole and the positive tab be connected, but also the negative pole and the negative tab can be connected. In this way, the stable transmission of current between the tab 301 and the pole 201 can be ensured, and the problem of poor contact can be reduced. Secondly, by arranging the pair of connecting pieces 4 at intervals, the short circuit between the positive pole and the negative pole can be avoided, improving the safety of using the battery cell. Furthermore, by arranging the tabs 301 on the opposite sides on the opposite sides of the ear connecting portion 402 along the width direction of the electrode group 3, this design makes the internal structure of the battery cell more compact, thereby improving the space utilization rate inside the housing 1.

[0059] It should be noted that in this embodiment, the length direction of the electrode group 3 is the same as the length direction of the housing 1, the width direction of the electrode group 3 is the same as the width direction of the housing 1, and both the length direction of the electrode group 3 and the width direction of the electrode group 3 are Figure 1 consistent with the directions shown in

[0060] According to an embodiment of the present utility model, as Figure 6 shown, there is a gap between the ends of the bent portions 3012 on the opposite sides that are close to each other. Compared with stacking the bent portions 3012 of the two tab ears 301 on one connection piece 4 together, in this embodiment, leaving a gap between the ends of the bent portions 3012 on the opposite sides that are close to each other can reduce the thickness when the two tab ears 301 and one connection piece 4 are in a connected state, that is, reduce the occupation of the internal space of the housing 1 and improve the energy density of the battery cell.

[0061] According to an embodiment of the present utility model, as Figure 6 shown, a notch 4021 extending along the length direction of the electrode group 3 is provided on the tab ear connecting portion 402. The notch 4021 divides the tab ear connecting portion 402 into two sub-connecting portions 4022. The two sub-connecting portions 4022 correspond to a pair of tab ears 301 one by one and are respectively welded to the lower surfaces of the corresponding bent portions 3012. Since the welding method of the bent portion 3012 and the connection piece 4 can adopt ultrasonic welding, compared with taking the tab ear connecting portion 402 as a whole, in this embodiment, using the notch 4021 to divide the tab ear connecting portion 402 into two sub-connecting portions 4022 can avoid the influence of the vibration generated during the ultrasonic welding process on the entire tab ear connecting portion 402 and ensure the stability and quality of the welding of each sub-connecting portion 4022 to the corresponding tab ear 301.

[0062] According to an embodiment of the present utility model, the cover plate 2 is welded to the housing 1. In this embodiment, welding the cover plate 2 and the housing 1 together can, on the one hand, ensure the connection strength between the two; on the other hand, it can ensure the sealing effect at the connection between the two, reduce the risk of impurities entering the interior of the battery cell, and ensure the stability and safety of the battery cell.

[0063] According to an embodiment of the present utility model, on the other hand, a battery pack is further provided, including: a plurality of the above-mentioned battery cells. By adopting the above-mentioned battery cells, the battery pack in this embodiment can improve its space utilization rate, so that without changing its own volume, it can improve its energy density, extend its usage time or reduce the charging frequency. Secondly, the explosion-proof valve 5 is arranged on the side of the housing 1 far away from the opening. On the one hand, it can reduce the occupation of the space on the cover plate 2 and optimize the layout; on the other hand, compared with arranging the explosion-proof valve 5 on the cover plate 2, it can reduce the possibility of damaging the structure (such as the pole column) on the cover plate 2 during the pressure relief process of the explosion-proof valve 5. In addition, the battery pack in this embodiment has all the advantages of the above-mentioned battery cells and will not be elaborated here.

[0064] It should be noted that the battery cells in this embodiment may be, but are not limited to, lithium-ion batteries, lithium manganate batteries, and nickel cobalt manganese ternary material batteries. Specifically, taking the lithium-ion battery as an example, the battery pack in this embodiment may be formed by connecting multiple lithium-ion batteries in series, or by connecting multiple lithium-ion batteries in parallel, or by preparing multiple lithium-ion batteries in a combination of series and parallel. Specific adjustments can be made according to the actual application scenarios and requirements. In this regard, the present utility model does not make specific limitations.

[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 fall within the scope defined by the appended claims.

Claims

1. A battery cell, characterized in that, Comprising: A housing, provided with a cavity and an opening communicating with the cavity; A cover plate, disposed on the opening to seal the cavity, the cover plate is provided with a terminal post, and one end of the terminal post is located in the cavity; An electrode assembly, disposed in the cavity and provided with electrode tabs, the electrode tabs are arranged in a staggered manner with the terminal post, the electrode tab includes a body connected to the electrode assembly and a bent portion bent from the end of the body towards one side; A connecting piece, disposed in the cavity and on the electrode assembly, for connecting the terminal post and the electrode tab, the connecting piece is fixed in the space defined by the body and the bent portion and is in contact with the lower surface of the bent portion; An explosion-proof valve, disposed on the side of the housing away from the opening; A pair of the terminal posts spaced apart along the length direction are provided on the cover plate, a through hole is provided between the pair of terminal posts, the through hole is provided on the cover plate and communicates with the cavity; The connecting piece includes a terminal post connecting portion connected to the terminal post and an electrode tab connecting portion connected to the electrode tab, a transition connecting portion is formed between the electrode tab connecting portion and the terminal post connecting portion, and the position of the through hole corresponds to the position of the electrode tab connecting portion; A pair of the connecting pieces spaced apart along the length direction are provided on the electrode assembly, the electrode tabs are respectively provided on opposite sides of each connecting piece, the electrode tabs on opposite sides are respectively located on opposite sides of the electrode tab connecting portion along the width direction of the electrode assembly, and their respective bent portions are bent and extended towards each other; A notch extending along the length direction of the electrode assembly is provided on the electrode tab connecting portion, the notch divides the electrode tab connecting portion into two sub-connecting portions, the two sub-connecting portions correspond to the pair of electrode tabs one by one, and are respectively welded to the lower surface of the corresponding bent portion.

2. The battery cell according to claim 1, wherein, A sealing plate is provided on the cover plate, the sealing plate seals the through hole and a liquid injection hole is provided on the sealing plate.

3. The battery cell according to claim 1, characterized in that, The shape of the through hole is rectangular and the length direction of the through hole is consistent with the length direction of the cover plate.

4. The battery cell according to claim 1, wherein A gap is left between the ends of the bent portions on opposite sides close to each other.

5. The battery cell according to any one of claims 1 to 4, characterized in that The cover plate is welded to the housing.

6. A battery pack, characterized in that, Comprising: Multiple battery cells according to any one of claims 1 to 5.

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