Square-shell battery cell and battery pack

Abstract

The utility model relates to the technical field of batteries, and discloses a square-shell battery cell and a battery pack. Wherein the square shell battery cell comprises a shell, a pole group, a cover plate, a negative electrode welding bottom plate, a positive electrode welding bottom plate and a sealing plate, the pole group is arranged in the accommodating cavity, a negative electrode lug and a positive electrode lug are arranged at one end of the pole group, and the negative electrode welding bottom plate and the positive electrode welding bottom plate are arranged in one-to-one correspondence with the negative electrode lug and the positive electrode lug and are arranged below the cover plate; end plates and plastic parts are respectively arranged on two sides of the negative electrode welding bottom plate and the positive electrode welding bottom plate, through holes for the negative electrode lug and the positive electrode lug to penetrate through are formed in the end plates and the plastic parts, and the negative electrode welding bottom plate and the positive electrode welding bottom plate respectively extend to the through holes and are propped against the negative electrode lug and the positive electrode lug. According to the utility model, the negative pole lug and the positive pole lug are bent through the through holes, and the pole group is arranged in the shell, so that the pole group does not need to be clamped and fixed, the pole lugs are convenient to bend, and the risk of breakage of the pole lugs is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a square shell 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 electrical energy. Among them, a square shell battery cell is a common battery design and is widely used in fields such as new energy vehicles and energy storage systems.

[0003] In the prior art, during the production process of a square shell battery cell, it is usually necessary to bend the tab or connecting piece of the battery cell. In this process, it is necessary to clamp and fix the electrode group to ensure that the tab or connecting piece can be accurately bent in place. However, when bending the tab or connecting piece, the tab may be torn, thus affecting the performance and safety of the battery cell. Summary of the Utility Model

[0004] In view of this, the utility model provides a square shell battery cell and a battery pack to solve the problem that the tab may be torn when bending the tab or connecting piece.

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

[0006] A housing, which is provided with a receiving cavity and an opening communicating with the receiving cavity;

[0007] An electrode group, which is arranged in the receiving cavity and one end of the electrode group is provided with a negative tab and a positive tab;

[0008] A cover plate, which is covered at the opening, and through holes for the negative tab and the positive tab to pass through are opened on the cover plate;

[0009] A negative welding bottom plate and a positive welding bottom plate, which are arranged corresponding to the negative tab and the positive tab one by one and are arranged below the cover plate. End plates and plastic parts are respectively arranged on both sides of the negative welding bottom plate and the positive welding bottom plate. Through holes for the negative tab and the positive tab to pass through are opened on both the end plates and the plastic parts. The negative welding bottom plate and the positive welding bottom plate respectively extend to the through holes and are in contact with the negative tab and the positive tab;

[0010] A sealing plate, which is arranged corresponding to the through hole, and the sealing plate is covered at the through hole to seal the receiving cavity.

[0011] Beneficial effects: When assembling the square shell battery cell, the electrode group is first loaded into the accommodating cavity from the opening of the shell. Next, the positive electrode welding base plate and the negative electrode welding base plate are arranged at the bottom of the cover plate, and plastic parts are arranged between the positive electrode welding base plate, the negative electrode welding base plate and the cover plate, and the plastic parts ensure the insulation between the positive electrode welding base plate, the negative electrode welding base plate and the cover plate. Since a through hole is provided on the end plate, the end plate is arranged on the electrode group and the positive electrode ear and the negative electrode ear pass through the through hole of the end plate, and the electrode group is insulated from the positive electrode welding base plate and the negative electrode welding base plate through the end plate. Subsequently, the cover plate is arranged at the opening of the shell. The position of the through hole on the cover plate corresponds to the position of the negative electrode ear and the positive electrode ear, and the negative electrode ear and the positive electrode ear pass through the through hole of the plastic part and pass out from the through hole. The positive electrode welding bottom plate and the negative electrode welding bottom plate extend to the through hole, and by bending the negative electrode tab and the positive electrode tab, the negative electrode welding bottom plate and the positive electrode welding bottom plate are in contact with the negative electrode tab and the positive electrode tab respectively. The installer can weld and fix the negative electrode welding bottom plate and the negative electrode tab, and the positive electrode welding bottom plate and the positive electrode tab through the through hole. Finally, the sealing plate cover is set at the through hole and the accommodating cavity is sealed to complete the assembly of the battery cell.

[0012] By opening a through hole on the cover plate, on the one hand, the welding base plate and the pole ear can be welded and connected through the through hole, thereby avoiding the space occupied by the bending of the pole ear after welding, shortening the length of the pole ear, and increasing the use space of the accommodating cavity in the shell in the length direction, thereby improving the internal space utilization of the battery cell. At the same time, when bending the pole ear, the negative pole ear and the positive pole ear can be bent through the through hole. Since the pole group is installed in the shell, there is no need to clamp and fix the pole group, which facilitates the bending of the pole ear and avoids the risk of the pole ear breaking. On the other hand, liquid can be injected into the accommodating cavity through the through hole, without the need to open a separate injection hole on the shell or cover plate.

[0013] In an optional embodiment, the sealing plate includes a sealing plate body and a plastic plate, wherein the plastic plate is disposed on one side of the sealing plate body and is located between the negative electrode tab, the positive electrode tab and the sealing plate body.

[0014] Beneficial effect: By arranging a plastic plate between the negative electrode tab, the positive electrode tab and the sealing plate body, the plastic plate can prevent the negative electrode tab and the positive electrode tab from directly contacting the sealing plate body, thereby avoiding short circuit of the battery cell. At the same time, the plastic plate can improve the sealing performance between the sealing cover and the cover body, ensure the sealing inside the battery cell, and prevent electrolyte leakage.

[0015] In an optional embodiment, each of the through hole and the sealing plate is provided with one, and an explosion-proof valve is provided on the sealing plate.

[0016] Beneficial effects: By providing only one through hole and one sealing plate on the cover plate, the assembly process of the sealing plate can be simplified, the assembly steps can be reduced, and the assembly efficiency can be improved. The sealing plate is provided with an explosion-proof valve, which can automatically open when the internal pressure of the battery cell is too high, release the internal pressure, prevent the battery cell from exploding or being damaged, and improve the safety of the battery cell.

[0017] In an alternative embodiment, two through holes and two sealing plates are provided. One through hole corresponds to the negative electrode tab, and the other through hole corresponds to the positive electrode tab. An explosion-proof valve is provided on the cover plate between the two through holes.

[0018] Beneficial effects: By providing two through holes, with each through hole corresponding to the respective tab, the layout of the positive electrode tab and the negative electrode tab can be optimized, the space required for tab bending can be reduced, and the usable space of the accommodation cavity inside the housing in the length direction can be improved. By arranging the explosion-proof valve between the two through holes, the internal pressure distribution of the battery cell can be better balanced, which helps to improve safety. When the internal pressure of the battery cell is too high, it can automatically open, release the internal pressure, prevent the battery cell from exploding or being damaged, and improve the safety of the battery cell.

[0019] In an alternative embodiment, a converging inclined surface is formed at the connection between the negative electrode tab and the positive electrode tab and the electrode group, and the bottom surface of the end plate is provided as an inclined surface that fits the converging inclined surface.

[0020] Beneficial effects: Since a converging inclined surface is formed at the connection between the negative electrode tab and the positive electrode tab and the electrode group, by providing the bottom surface of the end plate as an inclined surface that fits the converging inclined surface, when the end plate is installed on the electrode group, it ensures a tight fit between the tab and the end plate, and the inclined surface on the end plate presses down on the converging inclined surface at the connection between the tab and the electrode group, avoiding the risk of breakage during the tab bending process.

[0021] In an alternative embodiment, a bottom plate is further included. An installation opening communicating with the accommodation cavity is provided at the bottom of the housing, and the bottom plate is sealingly provided at the installation opening and the housing and the cover plate are integrally formed.

[0022] Beneficial effects: The housing and the cover plate are integrally formed, which can improve the structural integrity and structural strength of the entire assembly, simplify the assembly process, and reduce the number of components required for assembly.

[0023] The bottom plate is sealingly provided at the installation opening, which helps to improve the structural stability of the entire assembly and reduce loosening or deformation caused by vibration or external forces during use.

[0024] In an alternative embodiment, a stepped groove is provided around the through hole on the cover plate, and stepped surfaces corresponding to the stepped groove are provided around the sealing plate. The sealing plate and the cover plate are hermetically connected through the cooperation of the stepped groove and the stepped surfaces.

[0025] Advantageous effects: By providing a stepped groove around the through hole and stepped surfaces around the sealing plate, the cooperation between the stepped groove and the stepped surfaces can improve the sealing performance between the sealing plate and the cover plate, ensure the sealing inside the battery cell, prevent electrolyte leakage, and at the same time, simplify the assembly process of the sealing plate through the cooperation between the stepped groove and the stepped surfaces, improving the assembly efficiency.

[0026] In an alternative embodiment, both the negative electrode tab and the positive electrode tab are bent. The bent section of the negative electrode tab is arranged between the negative electrode welding bottom plate and the cover plate, and the bottom surface of the bent section of the negative electrode tab abuts against the top surface of the negative electrode welding bottom plate;

[0027] The bent section of the positive electrode tab is arranged between the positive electrode welding bottom plate and the cover plate, and the bottom surface of the bent section of the positive electrode tab abuts against the top surface of the positive electrode welding bottom plate.

[0028] Advantageous effects: Arranging the bent section of the negative electrode tab between the negative electrode welding bottom plate and the cover plate can reduce the space occupied by the negative electrode tab inside the housing, improve the utilization rate of the space inside the housing, and thus increase the energy density of the battery cell. The close contact between the negative electrode tab and the negative electrode welding bottom plate can ensure stable electrical connection, improve the reliability of the electrical connection, avoid the risk of poor contact or short circuit, and improve the overall safety of the product.

[0029] Similarly, arranging the bent section of the positive electrode tab between the positive electrode welding bottom plate and the cover plate can reduce the space occupied by the positive electrode tab inside the housing, improve the utilization rate of the space inside the housing, and thus increase the energy density of the battery cell. The close contact between the positive electrode tab and the positive electrode welding bottom plate can ensure stable electrical connection, improve the reliability of the electrical connection, avoid the risk of poor contact or short circuit, and improve the overall safety of the product.

[0030] In an alternative embodiment, both the negative electrode tab and the positive electrode tab are bent into an "L" shape.

[0031] Advantageous effects: During the assembly of the battery cell, after passing the negative electrode tab and the positive electrode tab through the through holes of the end plate and the plastic part and the through hole of the cover plate, only by bending the negative electrode tab and the positive electrode tab into an "L" shape can the tabs abut against the welding bottom plate, which not only improves the reliability of the electrical connection and the structural stability, but also simplifies the assembly process.

[0032] In a second aspect, the present utility model further provides a battery pack, comprising: a plurality of square-shell battery cells.

[0033] Advantageous effects: This battery pack includes the square-shell battery cells as described above, and thus has all the beneficial technical effects of the square-shell battery cells, which will not be elaborated herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the specific embodiments of the present utility model or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0035] Figure 1 Structural schematic diagram of a square-shell battery cell according to an embodiment of the present utility model;

[0036] Figure 2 Explosion schematic diagram of a square-shell battery cell according to an embodiment of the present utility model;

[0037] Figure 3 Structural schematic diagram of a pole group in a square-shell battery cell according to an embodiment of the present utility model;

[0038] Figure 4 Structural schematic diagram of an end plate in a square-shell battery cell according to an embodiment of the present utility model;

[0039] Figure 5 Structural schematic diagram of the end plate mounted on the pole group in a square-shell battery cell according to an embodiment of the present utility model;

[0040] Figure 6 Structural schematic diagram of an insulating film in a square-shell battery cell according to an embodiment of the present utility model;

[0041] Figure 7 For Figure 6 Structural schematic diagram of the insulating film mounted on the pole group;

[0042] Figure 8 Structural schematic diagram of another insulating film in a square-shell battery cell according to an embodiment of the present utility model;

[0043] Figure 9 For Figure 8 Structural schematic diagram of the insulating film mounted on the pole group;

[0044] Figure 10 For Figure 8 Structural schematic diagram of the insulating film mounted on the pole group and the end plate;

[0045] Figure 11Schematic diagram of the structure of the tab assembly in a square shell battery cell before bending according to an embodiment of the present utility model;

[0046] Figure 12 Schematic diagram of the structure of the plastic part in a square shell battery cell according to an embodiment of the present utility model;

[0047] Figure 13 Schematic diagram of the structure of the tab assembly in a square shell battery cell after bending according to an embodiment of the present utility model;

[0048] Figure 14 Schematic diagram of the structure of a square shell battery cell according to an embodiment of the present utility model;

[0049] Figure 15 Schematic diagram of the structure of the sealing plate in a square shell battery cell according to an embodiment of the present utility model;

[0050] Figure 16 Front view of a square shell battery cell according to an embodiment of the present utility model;

[0051] Figure 17 is Figure 16 Cross-sectional view taken along line A-A in

[0052] Figure 18 is Figure 17 Partial enlarged schematic view of

[0053] Figure 19 is Figure 16 Cross-sectional view taken along line B-B in

[0054] Figure 20 is Figure 19 Partial enlarged schematic view of

[0055] Figure 21 Top view of a square shell battery cell according to an embodiment of the present utility model;

[0056] Figure 22 is Figure 21 Cross-sectional view taken along line C-C in

[0057] Figure 23 is Figure 22 Partial enlarged schematic view of

[0058] Explanation of reference numerals:

[0059] 1. Housing; 2. Electrode assembly; 2011. Negative electrode tab; 20111. Bent section; 2012. Positive electrode tab; 2013. Converging inclined surface; 3. Cover plate; 301. Through hole; 302. Step groove; 401. Negative electrode welding bottom plate; 402. Positive electrode welding bottom plate; 5. End plate; 501. Through hole; 502. Inclined surface; 6. Plastic part; 7. Sealing plate; 701. Step surface; 702. Sealing plate body; 703. Plastic plate; 8. Explosion-proof valve; 9. Bottom plate; 10. Insulating film; 11. Negative electrode terminal; 12. Positive electrode terminal. Detailed implementation manners

[0060] 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.

[0061] In related technologies, during the production process of square shell battery cells, it is usually necessary to bend the electrode tabs or connection pieces of the battery cells. In this process, it is necessary to clamp and fix the electrode assembly to ensure that the electrode tabs or connection pieces can be accurately bent in place. However, when bending the electrode tabs or connection pieces, the electrode tabs may be torn, thus affecting the performance and safety of the battery cell.

[0062] To solve the above technical problems, the following will be combined with Figures 1 to 23 , to describe the embodiments of the present utility model.

[0063] According to the embodiments of the present utility model, on the one hand, as Figures 1 to 23 shown, a square shell battery cell is provided, including a housing 1, an electrode assembly 2, a cover plate 3, a negative electrode welding bottom plate 401, a positive electrode welding bottom plate 402 and a sealing plate 7.

[0064] Specifically, as Figure 1 and Figure 2 shown, the housing 1 is provided with a receiving cavity (not shown in the figure) and an opening (not shown in the figure), and the opening is communicated with the receiving cavity.

[0065] Specifically, in combination with Figure 2 and Figure 3 shown, one end of the electrode assembly 2 is provided with a negative electrode tab 2011 and a positive electrode tab 2012, and the electrode assembly 2 is arranged in the receiving cavity of the housing 1.

[0066] Specifically, as Figure 11As shown, the cover plate 3 covers the opening. Among them, a through hole 301 is formed in the cover plate 3, and the negative electrode tab 2011 and the positive electrode tab 2012 are adapted to pass through the through hole 301.

[0067] Specifically, as Figures 17 to 23 shown, the negative welding bottom plate 401 and the positive welding bottom plate 402 are arranged in one-to-one correspondence with the negative electrode tab 2011 and the positive electrode tab 2012, and the negative welding bottom plate 401 and the positive welding bottom plate 402 are arranged below the cover plate 3. Among them, end plates 5 and plastic parts 6 are respectively arranged on both sides of the negative welding bottom plate 401 and the positive welding bottom plate 402, and through holes 501 for the negative electrode tab 2011 and the positive electrode tab 2012 to pass through are formed in both the end plates 5 and the plastic parts 6.

[0068] Specifically, as Figure 23 shown, the negative welding bottom plate 401 and the positive welding bottom plate 402 respectively extend to the through hole 301, and the negative welding bottom plate 401 and the positive welding bottom plate 402 are in corresponding abutment with the negative electrode tab 2011 and the positive electrode tab 2012.

[0069] Specifically, as Figure 2 、 Figure 13 and Figure 14 shown, the sealing plate 7 is arranged corresponding to the through hole 301, and the sealing plate 7 covers the through hole 301 and seals the accommodating cavity.

[0070] For this square-shell battery cell, when assembling the battery cell, first insert the electrode assembly 2 into the accommodation cavity from the opening of the housing 1. Then, arrange the positive welding bottom plate 402 and the negative welding bottom plate 401 at the bottom of the cover plate 3, and place a plastic part 6 between the positive welding bottom plate 402 and the negative welding bottom plate 401 and the cover plate 3 to ensure insulation between the positive welding bottom plate 402 and the negative welding bottom plate 401 and the cover plate 3 through the plastic part 6. Since the end plate 5 is provided with a through hole 501, place the end plate 5 on the electrode assembly 2 and make the positive electrode tab 2012 and the negative electrode tab 2011 pass through the through hole 501 of the end plate 5, so that the electrode assembly 2 is insulated from the positive welding bottom plate 402 and the negative welding bottom plate 401 through the end plate 5. Subsequently, cover the cover plate 3 at the opening of the housing 1. The position of the through hole 301 on the cover plate 3 corresponds to the positions of the negative electrode tab 2011 and the positive electrode tab 2012. The negative electrode tab 2011 and the positive electrode tab 2012 pass through the through hole 501 of the plastic part 6 and extend out from the through hole 301. The positive welding bottom plate 402 and the negative welding bottom plate 401 extend to the through hole 301. By bending the negative electrode tab 2011 and the positive electrode tab 2012, the negative welding bottom plate 401 and the positive welding bottom plate 402 are correspondingly abutted against the negative electrode tab 2011 and the positive electrode tab 2012, and the installer can perform welding fixation on the negative welding bottom plate 401 and the negative electrode tab 2011, the positive welding bottom plate 402 and the positive electrode tab 2012 through the through hole 301. Finally, cover the sealing plate 7 at the through hole 301 and seal the accommodation cavity to complete the assembly of the battery cell.

[0071] By providing the through hole 301 on the cover plate 3, on the one hand, the welding bottom plate 9 and the electrode tab can be welded and connected through the through hole 301, thus avoiding the space occupied by the bending of the electrode tab after welding, shortening the length of the electrode tab, increasing the usable space of the accommodation cavity in the housing 1 in the length direction, thereby improving the utilization rate of the internal space of the battery cell. At the same time, when bending the electrode tab, the negative electrode tab 2011 and the positive electrode tab 2012 can be bent through the through hole 301. Since the electrode assembly 2 is installed in the housing 1, it is not necessary to clamp and fix the electrode assembly 2, which is convenient for bending the electrode tab and avoids the risk of breakage of the electrode tab. On the other hand, liquid can be injected into the accommodation cavity through the through hole 301 without separately providing a liquid injection hole on the housing 1 or the cover plate 3.

[0072] Specifically, the housing 1 can be set in any shape such as a cuboid or a cube. In the embodiment of the present application, the shape of the housing 1 is not specifically limited. Exemplarily, the housing 1 can be set as a cuboid, the accommodation cavity is set in a cuboid shape similar to the housing 1, and the opening is provided at one end of the housing 1.

[0073] Specifically, the through hole 301 can be opened in the middle area of the cover plate 3 or in the end area close to the cover plate 3. It is only necessary to ensure that the positions of the positive electrode tab 2012 and the negative electrode tab 2011 correspond to the position of the through hole 301. The through hole 301 can be set in any existing shape such as a rounded rectangular hole, a square hole, a circular hole, etc. In the embodiment of the present application, the shape of the through hole 301 and its position on the cover plate 3 are not specifically limited.

[0074] Specifically, the negative electrode welding bottom plate 401 and the negative electrode post 11 can be fixed on the cover plate 3 by riveting, and the positive electrode welding bottom plate 402 and the positive electrode post 12 can be fixed on the cover plate 3 by riveting.

[0075] Specifically, the sealing plate 7 can be hermetically fixed at the through hole 301 by welding. In the embodiment of the present application, the connection method between the sealing plate 7 and the cover plate 3 is not specifically limited.

[0076] Specifically, one or more through holes 301 can be provided. In the embodiment of the present application, the number of through holes 301 is not specifically limited.

[0077] In one embodiment, as Figure 15 and Figure 20 shown, the sealing plate 7 includes a sealing plate body 702 and a plastic plate 703. The plastic plate 703 is arranged on one side of the sealing plate body 702, and the plastic plate 703 is arranged between the negative electrode tab 2011 and the positive electrode tab 2012 and the cover plate 3 body.

[0078] By arranging the plastic plate 703 between the negative electrode tab 2011 and the positive electrode tab 2012 and the sealing plate body 702, the plastic plate 703 is used to prevent the negative electrode tab 2011 and the positive electrode tab 2012 from directly contacting the sealing plate body 702, avoiding short - circuit of the battery cell. At the same time, the plastic plate 703 can improve the sealing performance between the sealing cover and the cover body, ensure the tightness inside the battery cell, and prevent electrolyte leakage.

[0079] Specifically, the sealing plate body 702 and the plastic plate 703 can be fixed by bonding, or can be fixed by injection molding or hot melting. In the embodiment of the present application, the connection method between the sealing plate body 702 and the plastic plate 703 is not specifically limited.

[0080] Specifically, the plastic plate 703, the plastic part 6 and the end plate 5 can be made of PP material.

[0081] In one embodiment, there is one through hole 301, and there is also one corresponding sealing plate 7 for the through hole 301, and an explosion - proof valve 8 is provided on the sealing plate 7.

[0082] By only providing one through-hole 301 and one sealing plate 7 on the cover plate 3, the assembly process of the sealing plate 7 can be simplified, the assembly steps can be reduced, and the assembly efficiency can be improved. An explosion-proof valve 8 is provided on the sealing plate 7, which can be automatically opened when the internal pressure of the battery cell is too high to release the internal pressure, prevent the battery cell from exploding or being damaged, and improve the safety of the battery cell.

[0083] In one embodiment, as Figure 13 and Figure 14 shown, there are two through-holes 301 and two sealing plates 7. Among them, one through-hole 301 corresponds to the negative electrode tab 2011, and the other through-hole 301 corresponds to the positive electrode tab 2012. An explosion-proof valve 8 is provided on the cover plate 3, and the explosion-proof valve 8 is located between the two through-holes 301.

[0084] By providing two through-holes 301, with each through-hole 301 corresponding to the respective tab, the layout of the positive electrode tab 2012 and the negative electrode tab 2011 can be optimized, the space required for tab bending can be reduced, and the usable space of the accommodation cavity in the housing 1 in the length direction can be improved. By arranging the explosion-proof valve 8 between the two through-holes 301, the internal pressure distribution of the battery cell can be better balanced, which helps to improve safety. When the internal pressure of the battery cell is too high, it will be automatically opened to release the internal pressure, prevent the battery cell from exploding or being damaged, and improve the safety of the battery cell.

[0085] Specifically, the shapes of the two through-holes 301 can be the same or different, and can be adjusted according to the shapes of the negative electrode tab 2011 and the positive electrode tab 2012 to ensure that the tabs pass through the through-holes 301. In the embodiments of the present application, the shapes and positions of the through-holes 301 are not specifically limited.

[0086] In one embodiment, as Figure 20 shown, a converging inclined surface 2013 is formed at the connection between the negative electrode tab 2011 and the positive electrode tab 2012 and the electrode group 2, and the bottom surface of the end plate 5 is provided with an inclined surface 502 that fits the converging inclined surface 2013.

[0087] Since a converging inclined surface 2013 will be formed at the connection between the negative electrode tab 2011 and the positive electrode tab 2012 and the electrode group 2, by providing an inclined surface 502 on the bottom surface of the end plate 5 that fits the converging inclined surface 2013, when the end plate 5 is installed on the electrode group 2, it is ensured that there is a tight fit between the tab and the end plate 5, so that the inclined surface 502 on the end plate 5 presses down on the converging inclined surface 2013 at the connection between the tab and the electrode group 2, avoiding the risk of breakage during the tab bending process.

[0088] Specifically, the inclination angle and inclination direction of the inclined surface 502 on the bottom surface of the end plate 5 are adapted to those of the converging inclined surface 2013. In the embodiments of the present application, the inclination angle and inclination direction of the inclined surface 502 are not specifically limited.

[0089] In one embodiment, as Figure 2 shown, it further includes a bottom plate 9. An installation opening communicating with the accommodation cavity is formed at the bottom of the housing 1. The bottom plate 9 is sealingly arranged at the installation opening, and the housing 1 and the cover plate 3 are integrally formed.

[0090] The housing 1 and the cover plate 3 being integrally formed can improve the structural integrity and strength of the entire assembly, simplify the assembly process, and reduce the number of components required for assembly.

[0091] The bottom plate 9 being sealingly arranged at the installation opening helps to improve the structural stability of the entire assembly and reduce loosening or deformation caused by vibration or external forces during use.

[0092] In one embodiment, as Figure 20 shown, a stepped groove 302 is provided on the cover plate 3 around the through hole 301. Step surfaces 701 corresponding to the stepped groove 302 are provided around the sealing plate 7. The sealing plate 7 and the cover plate 3 are sealingly connected through the cooperation of the stepped groove 302 and the step surfaces 701.

[0093] By providing the stepped groove 302 around the through hole 301 and the step surfaces 701 around the sealing plate 7, the cooperation of the stepped groove 302 and the step surfaces 701 can improve the sealing performance between the sealing plate 7 and the cover plate 3, ensure the sealing inside the battery cell, prevent electrolyte leakage, and at the same time, through the cooperation of the stepped groove 302 and the step surfaces 701, the assembly process of the sealing plate 7 is simplified and the assembly efficiency is improved.

[0094] Specifically, during the installation of the sealing plate 7, through the cooperation of the stepped groove 302 and the step surfaces 701, the sealing plate 7 can be quickly positioned, and by presetting the positions of the stepped groove 302 and the step surfaces 701, it can be ensured that the top surface of the sealing plate 7 is in the same plane as the top surface of the cover body, ensuring the neat and beautiful appearance of the battery cell.

[0095] In one embodiment, as Figure 23 shown, both the negative electrode tab 2011 and the positive electrode tab 2012 are bent. The bent section 20111 of the negative electrode tab 2011 is arranged between the negative electrode welding bottom plate 401 and the cover plate 3, and the bottom surface of the bent section 20111 of the negative electrode tab 2011 abuts against the top surface of the negative electrode welding bottom plate 401.

[0096] The bent section 20111 of the positive electrode tab 2012 is arranged between the positive electrode welding bottom plate 402 and the cover plate 3, and the bottom surface of the bent section 20111 of the positive electrode tab 2012 abuts against the top surface of the positive electrode welding bottom plate 402.

[0097] The bent section 20111 of the negative electrode tab 2011 is arranged between the negative electrode welding bottom plate 401 and the cover plate 3, which can reduce the space occupied by the negative electrode tab 2011 inside the housing 1, improve the utilization rate of the space inside the housing 1, and thus improve the energy density of the battery cell. The close contact between the negative electrode tab 2011 and the negative electrode welding bottom plate 401 can ensure a stable electrical connection, improve the reliability of the electrical connection, avoid the risk of poor contact or short circuit, and improve the overall safety of the product.

[0098] Similarly, the bent section 20111 of the positive electrode tab 2012 is arranged between the positive electrode welding bottom plate 402 and the cover plate 3, which can reduce the space occupied by the positive electrode tab 2012 inside the housing 1, improve the utilization rate of the space inside the housing 1, and thus improve the energy density of the battery cell. The close contact between the positive electrode tab 2012 and the positive electrode welding bottom plate 402 can ensure a stable electrical connection, improve the reliability of the electrical connection, avoid the risk of poor contact or short circuit, and improve the overall safety of the product.

[0099] Specifically, the bent section 20111 can be set at any bending angle as long as it ensures close contact with the welding bottom plate 9. In the embodiment of the present application, the bending angle of the bent section 20111 is not specifically limited.

[0100] In one embodiment, as Figure 20 shown, both the negative electrode tab 2011 and the positive electrode tab 2012 are bent in an "L" shape.

[0101] During the process of assembling the battery cell, after passing the negative electrode tab 2011 and the positive electrode tab 2012 through the through holes 501 of the end plate 5 and the plastic part 6 and the through hole 301 of the cover plate 3, only by bending the negative electrode tab 2011 and the positive electrode tab 2012 into an "L" shape can the tabs be abutted against the welding bottom plate 9, which not only improves the reliability of the electrical connection and the structural stability, but also simplifies the assembly process.

[0102] Specifically, when bending the negative electrode tab 2011 and the positive electrode tab 2012, the negative electrode tab 2011 and the positive electrode tab 2012 can both be bent by 90°, so that the bent section 20111 of the negative electrode tab 2011 is in close contact with the top surface of the negative electrode welding bottom plate 401, and the bent section 20111 of the positive electrode tab 2012 is in close contact with the top surface of the positive electrode welding bottom plate 402.

[0103] The installation process of the battery cell in this embodiment is described as follows:

[0104] First, set the end plate 5 on the electrode group 2 and make the negative electrode tab 2011 and the positive electrode tab 2012 pass through the through holes 501 of the end plate 5, and then fold the insulating film 10 into a shape adapted to the electrode group 2 (such as Figure 6As shown, the insulating film 10 is sleeved on the electrode group 2, and the contact between the insulating film 10 and the end plate 5 is connected by heat melting to ensure that the insulating film 10 is firmly fixed. Alternatively, the insulating film 10 is directly wrapped on the electrode group 2, and corresponding reserved holes are provided on the insulating film 10 for the negative electrode tab 2011 and the positive electrode tab 2012, so that the negative electrode tab 2011 and the positive electrode tab 2012 pass through the reserved holes, and then the end plate 5 is installed on the electrode group 2.

[0105] Subsequently, the electrode group 2 is inserted into the accommodating cavity from the installation opening at the bottom of the housing 1, so that the negative electrode tab 2011 and the positive electrode tab 2012 on the electrode group 2 pass through the through hole 501 of the plastic part 6 and the through hole 301 of the cover plate 3. Among them, when the housing 1 is received, the plastic part 6 has been installed at the lower part of the cover plate 3.

[0106] After the electrode group 2 is inserted into the housing 1, the bottom plate 9 is welded at the installation opening, so that the electrode group 2 is sealed in the housing 1.

[0107] Then, the negative electrode tab 2011 and the positive electrode tab 2012 are bent into an "L" shape, and then the negative electrode tab 2011 and the negative welding bottom plate 401 are welded, and the positive electrode tab 2012 and the positive welding bottom plate 402 are welded.

[0108] After the welding of the bottom plate 9 and the electrode tab is completed, the electrolyte can be injected into the battery cell through the through hole 301. When the injection is completed, the sealing plate 7 is covered at the through hole 301 and the accommodating cavity is sealed, completing the assembly of the battery cell.

[0109] According to an embodiment of the present invention, on the other hand, a battery pack is further provided, including a plurality of square shell battery cells.

[0110] Specifically, a plurality of battery cells are connected in series and / or in parallel to form a plurality of battery cell modules, and the plurality of battery cell modules are assembled into a battery pack.

[0111] This battery pack includes the square shell battery cell as described above, so it has all the beneficial technical effects of the square shell battery cell, which will not be elaborated here.

[0112] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A square shell battery cell, characterized in that, Comprising: A housing, which is provided with a receiving cavity and an opening communicating with the receiving cavity; A pole group, which is arranged in the receiving cavity and one end of the pole group is provided with a negative pole tab and a positive pole tab; A cover plate, which is covered at the opening, and through holes for the negative pole tab and the positive pole tab to pass through are provided on the cover plate; A negative welding bottom plate and a positive welding bottom plate, which are arranged in one-to-one correspondence with the negative pole tab and the positive pole tab and are arranged below the cover plate. End plates and plastic parts are respectively arranged on both sides of the negative welding bottom plate and the positive welding bottom plate. Through holes for the negative pole tab and the positive pole tab to pass through are provided on both the end plates and the plastic parts. The negative welding bottom plate and the positive welding bottom plate respectively extend to the through holes and are in contact with the negative pole tab and the positive pole tab; A sealing plate, which is arranged corresponding to the through hole, and the sealing plate is covered at the through hole and seals the receiving cavity.

2. The square shell battery cell according to claim 1, wherein The sealing plate includes a sealing plate body and a plastic plate, and the plastic plate is arranged on one side of the sealing plate body and is located between the negative pole tab and the positive pole tab and the sealing plate body.

3. The square shell battery cell according to claim 1, wherein One through hole and one sealing plate are provided, and an explosion-proof valve is provided on the sealing plate.

4. The square shell battery cell according to claim 1, wherein Two through holes and two sealing plates are provided. One through hole corresponds to the negative pole tab, and the other through hole corresponds to the positive pole tab. An explosion-proof valve is provided on the cover plate between the two through holes.

5. The square shell battery cell according to claim 1, wherein Converging inclined surfaces are formed at the connection parts of the negative pole tab and the positive pole tab and the pole group, and the bottom surface of the end plate is set as an inclined surface that fits with each converging inclined surface.

6. The square shell battery cell according to any one of claims 1 to 5, characterized in that, It further includes a bottom plate. An installation opening communicating with the receiving cavity is provided at the bottom of the housing, and the bottom plate is hermetically arranged at the installation opening and the housing and the cover plate are integrally formed.

7. The square shell battery cell according to any one of claims 1 to 5, characterized in that, A stepped groove is provided on the cover plate around the periphery of the through hole, and a stepped surface corresponding to the stepped groove is provided around the periphery of the sealing plate. The sealing plate and the cover plate are hermetically connected through the cooperation of the stepped groove and the stepped surface.

8. The square shell battery cell according to any one of claims 1 to 5, characterized in that, The negative pole tab and the positive pole tab are both bent. The bent section of the negative pole tab is arranged between the negative welding bottom plate and the cover plate, and the bottom surface of the bent section of the negative pole tab is in contact with the top surface of the negative welding bottom plate; The bent section of the positive pole tab is arranged between the positive welding bottom plate and the cover plate, and the bottom surface of the bent section of the positive pole tab is in contact with the top surface of the positive welding bottom plate.

9. The square shell battery cell according to any one of claims 1 to 5, characterized in that, The negative pole tab and the positive pole tab are both bent into an "L" shape.

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

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