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 pole group, a shell and a sealing plate, a through hole is formed in the middle area of the top wall of the shell, a negative pole lug and a positive pole lug penetrate through the through hole, the through hole is provided with a stepped groove which is formed around the inner wall of the through hole, and the stepped groove comprises a first groove section and a second groove section which are arranged up and down; the size of the first groove section is larger than that of the second groove section, a step face is formed at the joint of the first groove section and the second groove section, the bottom face of the sealing plate abuts against the step face, and the side wall of the sealing plate is welded to the inner wall of the first groove section. According to the utility model, the top wall of the shell is provided with the through hole, the through hole is arranged in the middle area of the top wall, and the welding bottom plate and the tabs are welded and connected through the through hole, so that the situation that the tabs are bent after being welded to occupy space is avoided, the length of the tabs is shortened, and the use space of the accommodating cavity in the shell in the length direction is increased; therefore, the internal space utilization rate of the cell is improved.

Description

Technical Field

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

[0002] As battery technology matures, batteries are widely used in electric vehicles and energy storage, and the requirements for battery performance and safety are increasing. A battery cell is the basic component of a battery, capable of independently generating and storing electrical energy.

[0003] In the prior art, both the connecting piece and the tab need to be bent, and the connecting piece, the pole and the tab are usually located on the same vertical plane, thus occupying a large space in the battery cell, resulting in low space utilization of the battery cell. Utility Model Content

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

[0005] In a first aspect, the present invention provides a battery cell, comprising:

[0006] The electrode group has a negative electrode tab and a positive electrode tab at one end;

[0007] A housing is provided with an accommodating cavity for accommodating the electrode group, a through-hole is provided in the middle area of ​​the top wall of the housing, the through-hole is for the negative electrode tab and the positive electrode tab to pass through, the through-hole is provided with a stepped groove arranged around the inner wall of the through-hole, the stepped groove includes a first groove section and a second groove section arranged above and below, the size of the first groove section is larger than the size of the second groove section, and a step surface is formed at the connection between the first groove section and the second groove section;

[0008] A sealing plate is provided to cover the through hole, the bottom surface of the sealing plate abuts against the step surface, and the side wall of the sealing plate is welded to the inner wall of the first groove section.

[0009] Beneficial effects: When assembling this battery cell, the electrode assembly is first placed into the housing cavity of the shell. Since a through-hole is provided on the top wall of the shell, and the through-hole corresponds to the position of the negative electrode tab and the positive electrode tab, the negative electrode tab and the positive electrode tab on the electrode assembly pass through the through-hole on the top wall. The installer can bend the negative electrode tab and the positive electrode tab through the through-hole so that the negative electrode tab and the positive electrode tab respectively abut against the negative electrode welding base plate and the positive electrode welding base plate. The installer can also weld and fix the negative electrode welding base plate and the negative electrode tab, and the positive electrode welding base plate and the positive electrode tab through the through-hole. Finally, a sealing plate cover is placed on the through-hole and the housing cavity is sealed to complete the assembly of the battery cell.

[0010] By opening a through hole in the top wall of the shell and arranging the through hole in the middle area of ​​the top wall, the welding base plate and the tab can be welded together through the through hole, thereby avoiding the space occupied by the tab bending after welding, shortening the length of the tab, and increasing the usable space of the accommodating cavity in the shell in the length direction, thereby improving the internal space utilization of the battery cell. Because the inner wall of the through hole is provided with a stepped groove, and the junction of the first groove section and the second groove section of the stepped groove forms a stepped surface, the stepped surface is abutted against the bottom surface of the sealing plate, and the side wall of the sealing plate is welded to the inner wall of the first groove section, which can ensure close contact between the sealing plate and the through hole, improve the sealing performance, and reduce the risk of electrolyte leakage. The welding of the side wall of the sealing plate to the inner wall of the through hole enhances the connection strength, further improving the sealing effect.

[0011] In an optional embodiment, the length of the sealing plate is a, the length of the top wall is A, and 0.5A≤a≤0.7A;

[0012] The width of the sealing plate is b, the width of the top wall is B, and b≥0.3B.

[0013] Beneficial effect: By ensuring that the length a and width b of the sealing plate are in an appropriate ratio to the length A and width B of the top wall, the connection strength between the sealing plate and the top wall can be improved, which helps to improve the structural stability of the entire component. At the same time, within the above-mentioned ratio range, it can ensure that the negative electrode tab and the positive electrode tab can pass through the through hole smoothly, and the width of the negative electrode tab and the positive electrode tab after bending can be adapted to the width of the through hole, so as to facilitate welding of the negative electrode tab and the negative electrode welding base plate, and the positive electrode tab and the positive electrode welding base plate through the through hole.

[0014] In an optional embodiment, a liquid injection hole is opened on the sealing plate, and the liquid injection hole is located in the middle area of ​​the sealing plate.

[0015] Beneficial Effects: Placing the injection hole in the middle of the sealing plate helps the electrolyte diffuse more evenly within the battery cell, ensuring a uniform distribution of the electrolyte within the cell, improving both electrolyte distribution uniformity and injection efficiency. Furthermore, placing the injection hole in the middle of the sealing plate simplifies the injection process, facilitating operator positioning of the injection hole and improving assembly efficiency.

[0016] In an optional embodiment, a bottom plate is further included. An opening is provided at the bottom of the shell. The bottom plate cover is provided at the opening and seals the accommodating cavity. An explosion-proof valve is provided on the bottom plate.

[0017] Beneficial Effects: By providing an opening at the bottom of the housing, the electrode assembly can be placed into the housing cavity through the opening. By placing a bottom plate cover over the opening, the electrode assembly is sealed within the housing cavity. Because the bottom plate is provided with an explosion-proof valve, when the internal pressure of the housing is too high, the explosion-proof valve opens to release excess gas in the housing, preventing the battery cell from exploding. Furthermore, since the explosion-proof valve is located at the bottom of the housing and the injection port is located at the top of the housing, the explosion-proof valve and the injection port are positioned relative to each other, preventing residual electrolyte from contaminating the explosion-proof valve during injection.

[0018] In an optional embodiment, the thickness of the sealing plate is smaller than the groove depth of the first groove section, and the thickness of the sealing plate is 0.2 mm to 0.4 mm smaller than the groove depth of the first groove section.

[0019] Beneficial Effects: By setting the thickness of the sealing plate to be smaller than the depth of the first slot section, the raised point at the weld between the sealing plate and the first slot section is ensured not to protrude above the upper surface of the top wall, ensuring the flatness of the top wall's upper surface. This facilitates the subsequent assembly of other components and prevents interference between the welded raised point and other components during assembly. Furthermore, after the sealing plate is mated with the first slot section, it only occupies the space at the top wall, preventing it from extending into the housing and occupying space within the housing, thereby improving the internal space utilization of the battery cell.

[0020] Setting the thickness of the sealing plate to be 0.2mm to 0.4mm smaller than the groove depth of the first groove section can further ensure that the protrusion at the welding point between the sealing plate and the first groove section will not be higher than the upper surface of the top wall, thereby ensuring the flatness of the upper surface of the top wall, which is conducive to the subsequent assembly of other components and avoids interference between the welding protrusion and other components during the assembly process.

[0021] In an optional embodiment, the groove depth of the first groove section is t, the thickness of the top wall is T, and 0.25T≤t≤0.8T.

[0022] Beneficial effect: By controlling the ratio of the top wall thickness to the depth of the first groove section, close contact between the sealing plate and the inner wall of the first groove section can be ensured, thereby improving the sealing performance. At the same time, the strength and welding sealing of the sealing plate and the inner wall of the first groove section after welding can be ensured.

[0023] In an optional embodiment, a first chamfer is provided on the through hole around the top of the inner wall of the through hole, and a second chamfer is provided on the sealing plate around the bottom of the side wall of the sealing plate.

[0024] Beneficial effects: The design of the first chamfer and the second chamfer helps to guide the sealing plate to be accurately installed in the through hole, simplifies the assembly process, reduces the friction between the sealing plate and the inner wall of the through hole during assembly, and facilitates the sealing plate to be smoothly installed in the through hole.

[0025] In an optional embodiment, the sealing plate includes a sealing plate body and a plastic plate, wherein the plastic plate is provided 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.

[0026] Beneficial effect: By arranging a plastic plate between the negative electrode tab, the positive electrode tab and the sealing plate body, the plastic plate prevents 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 plate and the top wall, ensure the sealing inside the battery cell, and prevent electrolyte leakage.

[0027] In an optional embodiment, it further includes a negative electrode welding bottom plate and a positive electrode welding bottom plate, wherein the negative electrode welding bottom plate and the positive electrode welding bottom plate are arranged below the top wall, and the negative electrode welding bottom plate and the positive electrode welding bottom plate respectively extend to the through hole.

[0028] Beneficial effect: The positive electrode welding base plate and the negative electrode welding base plate are arranged below the top wall, and the positive electrode welding base plate and the negative electrode welding base plate extend to the through hole. By bending the negative electrode tab and the positive electrode tab, the negative electrode welding base plate and the positive electrode tab are correspondingly abutted. The installer can weld and fix the negative electrode welding base plate and the negative electrode tab, and the positive electrode welding base plate and the positive electrode tab through the through hole.

[0029] In a second aspect, the present invention also provides a battery pack comprising a plurality of battery cells.

[0030] Beneficial effects: This battery pack, including the battery cell as described above, has all the beneficial technical effects of the battery cell, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] 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 any creative work.

[0032] Figure 1 This is a schematic structural diagram of a battery cell according to an embodiment of the present utility model;

[0033] Figure 2 for Figure 1 A cross-sectional view of the battery cell shown;

[0034] Figure 3 for Figure 2 A partial enlarged schematic diagram;

[0035] Figure 4 for Figure 1 A top view of the battery cell shown;

[0036] Figure 5 This is a structural diagram of a battery cell with a hidden sealing plate according to an embodiment of the utility model;

[0037] Figure 6 for Figure 5 A cross-sectional view of the battery cell shown;

[0038] Figure 7 This is a schematic structural diagram of an electrode group in a battery cell according to an embodiment of the present invention.

[0039] Description of reference numerals:

[0040] 1. Pole group; 2. Negative electrode tab; 3. Positive electrode tab; 4. Shell; 401. Top wall; 4011. Through hole; 40111. First chamfer; 4012. Step groove; 40121. First groove section; 40122. Second groove section; 5. Sealing plate; 501. Liquid injection hole; 502. Second chamfer; 503. Sealing plate body; 504. Plastic plate; 6. Bottom plate; 7. Explosion-proof valve; 8. Negative electrode welding bottom plate; 9. Positive electrode welding bottom plate; 10. Plastic parts. DETAILED DESCRIPTION

[0041] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0042] In the related art, both the connecting piece and the tab need to be bent, and the connecting piece, the pole and the tab are usually located on the same vertical plane, so they need to occupy a larger space in the battery cell, resulting in low space utilization of the battery cell.

[0043] In order to solve the above technical problems, the following Figures 1 to 7 , describing the embodiments of the present utility model.

[0044] According to an embodiment of the present invention, on the one hand, Figures 1 to 7 As shown, a battery cell is provided, including a pole group 1, a shell 4 and a sealing plate 5.

[0045] Specifically, if Figure 7 As shown, one end of the electrode group 1 is provided with a negative electrode tab 2 and a positive electrode tab 3.

[0046] Specifically, if Figures 1 to 6As shown, the housing 4 is provided with a receiving cavity (not shown in the figure), and the electrode group 1 is suitable for being placed in the receiving cavity. The top wall 401 of the housing 4 is provided with a through hole 4011, and the through hole 4011 is located in the middle area of ​​the top wall 401. The negative electrode tab 2 and the positive electrode tab 3 are suitable for passing through the through hole 4011. Among them, the through hole 4011 is provided with a stepped groove 4012 arranged around the inner wall of the through hole 4011. The stepped groove 4012 includes a first groove section 40121 and a second groove section 40122. The first groove section 40121 and the second groove section 40122 are arranged one above the other. The size of the first groove section 40121 is larger than the size of the second groove section 40122, and a step surface is formed at the connection between the first groove section 40121 and the second groove section 40122.

[0047] Specifically, if Figures 1 to 5 As shown, the sealing plate 5 is covered at the through hole 4011 , the bottom surface of the sealing plate 5 abuts against the step surface, and the side wall of the sealing plate 5 is welded to the inner wall of the first groove section 40121 .

[0048] When assembling this battery cell, the electrode group 1 is first placed into the accommodating cavity of the housing 4. Since the top wall 401 of the housing 4 has a through-hole 4011, and the through-hole 4011 corresponds to the position of the negative electrode tab 2 and the positive electrode tab 3, the negative electrode tab 2 and the positive electrode tab 3 on the electrode group 1 pass through the through-hole 4011 on the top wall 401. The installer can bend the negative electrode tab 2 and the positive electrode tab 3 through the through-hole 4011 so that the negative electrode tab 2 and the positive electrode tab respectively abut against the negative electrode welding base plate 8 and the positive electrode welding base plate 9. The installer can also weld the negative electrode welding base plate 8 and the negative electrode tab 2, and the positive electrode welding base plate 9 and the positive electrode tab 3 through the through-hole 4011. Finally, the sealing plate 5 is placed over the through-hole 4011 to seal the accommodating cavity, completing the assembly of the battery cell.

[0049] By providing a through hole 4011 in the top wall 401 of the housing 4 and locating the through hole 4011 in the middle region of the top wall 401, the welding base plate 6 and the tab can be welded together through the through hole 4011, thereby avoiding the space occupied by the tab bending after welding, shortening the tab length, and increasing the usable space of the accommodating cavity in the housing 4 in the longitudinal direction, thereby improving the internal space utilization of the battery cell. Because the inner wall of the through hole 4011 is provided with a stepped groove 4012, and the junction of the first groove section 40121 and the second groove section 40122 of the stepped groove 4012 forms a stepped surface, the stepped surface abuts the bottom surface of the sealing plate 5, and the side wall of the sealing plate 5 is welded to the inner wall of the first groove section 40121, thereby ensuring close contact between the sealing plate 5 and the through hole 4011, improving the sealing performance and reducing the risk of electrolyte leakage. The welding of the side wall of the sealing plate 5 to the inner wall of the through hole 4011 strengthens the connection strength, further improving the sealing effect.

[0050] Specifically, the housing 4 can be configured in any shape such as a cuboid or a cube. In the embodiment of the present application, there is no specific limitation on the shape of the housing 4. For example, the housing 4 can be configured in a cuboid, and the accommodating cavity is configured in a cuboid shape similar to the housing 4.

[0051] Specifically, the size of the through hole 4011 is related to the area occupied by the negative electrode tab 2 and the positive electrode tab 3 on the electrode group 1. It is sufficient to ensure that the size of the through hole 4011 is large enough for the negative electrode tab 2 and the positive electrode tab 3 to pass through. In the embodiment of the present application, no specific restrictions are imposed on the negative electrode tab 2 and the positive electrode tab 3.

[0052] Specifically, the sizes of the first slot segment 40121 and the second slot segment 40122 can be adjusted according to design requirements, thereby adjusting the size of the step surface. In the embodiment of the present application, no specific restrictions are placed on the sizes of the first slot segment 40121 and the second slot segment 40122.

[0053] Specifically, the shape and size of the sealing plate 5 are adapted to the shape and size of the through hole 4011 . In the embodiment of the present application, the shape and size of the sealing plate 5 are not specifically limited.

[0054] In one embodiment, Figure 4 As shown, the length of the sealing plate 5 is a, the length of the top wall 401 is A, 0.5A≤a≤0.7A. The width of the sealing plate 5 is b, the width of the top wall 401 is B, b≥0.3B.

[0055] By ensuring that an appropriate ratio is maintained between the length a and width b of the sealing plate 5 and the length A and width B of the top wall 401, the connection strength between the sealing plate 5 and the top wall 401 can be improved, which helps to improve the structural stability of the entire component. At the same time, within the above-mentioned ratio range, it can ensure that the negative electrode tab 2 and the positive electrode tab 3 pass through the through hole 4011 smoothly, and the width of the negative electrode tab 2 and the positive electrode tab 3 after bending can be adapted to the width of the through hole 4011, so as to facilitate welding of the negative electrode tab 2 and the negative electrode welding base plate 8, and the positive electrode tab 3 and the positive electrode welding base plate 9 through the through hole 4011.

[0056] In one embodiment, Figure 1 As shown, a liquid injection hole 501 is opened on the sealing plate 5 , and the liquid injection hole 501 is located in the middle area of ​​the sealing plate 5 .

[0057] Placing the injection hole 501 in the middle of the sealing plate 5 facilitates more uniform diffusion of the electrolyte within the battery cell, ensuring a uniform distribution of the electrolyte within the battery cell, thereby improving both the uniformity of electrolyte distribution and the efficiency of injection. Furthermore, locating the injection hole 501 in the middle of the sealing plate 5 simplifies the injection process, facilitates easier positioning of the injection hole 501, and improves assembly efficiency.

[0058] Specifically, the injection hole 501 can be any shape, such as a circular hole, a square hole, etc. In the embodiment of the present application, there is no specific limitation on the shape of the injection hole 501.

[0059] In one embodiment, Figure 2 As shown, the housing 4 further includes a bottom plate 6 . An opening is provided at the bottom of the housing 4 . The bottom plate 6 covers the opening and seals the accommodating cavity. An explosion-proof valve 7 is provided on the bottom plate 6 .

[0060] An opening is provided at the bottom of the housing 4 to facilitate placement of the electrode assembly 1 into the accommodating cavity through the opening. A bottom plate 6 is placed over the opening, sealing the electrode assembly 1 within the accommodating cavity of the housing 4. An explosion-proof valve 7 is provided on the bottom plate 6. When the pressure inside the housing 4 is too high, the valve 7 opens to release excess gas inside the housing 4, preventing explosion of the battery cell. Furthermore, since the valve 7 is located at the bottom of the housing 4 and the injection port 501 is located at the top of the housing 4, the valve 7 and injection port 501 are positioned opposite each other, preventing contamination of the valve 7 by residual electrolyte during injection.

[0061] Specifically, the explosion-proof valve 7 can be set in the middle area of ​​the bottom plate 6, or can be set near the two ends of the bottom plate 6. In the embodiment of the present application, there is no specific restriction on the position of the explosion-proof valve 7 on the bottom plate 6.

[0062] In one embodiment, Figure 3 As shown, the thickness of the sealing plate 5 is smaller than the groove depth of the first groove section 40121 , and the thickness of the sealing plate 5 is 0.2 mm to 0.4 mm smaller than the groove depth of the first groove section 40121 .

[0063] By setting the thickness of sealing plate 5 to be less than the depth of first groove section 40121, on the one hand, it is possible to ensure that the protrusion at the welding point between sealing plate 5 and first groove section 40121 does not protrude above the upper surface of top wall 401, thereby ensuring the flatness of the upper surface of top wall 401, facilitating the subsequent assembly of other components and preventing interference between the welding protrusion and other components during assembly. On the other hand, after the sealing plate 5 is mated with first groove section 40121, it only occupies the space at top wall 401, preventing the sealing plate 5 from extending into the housing 4 and occupying the internal space of the housing 4, thereby improving the internal space utilization of the battery cell.

[0064] Setting the thickness of the sealing plate 5 to be 0.2 mm to 0.4 mm smaller than the groove depth of the first groove section 40121 can further ensure that the protrusion at the welding point between the sealing plate 5 and the first groove section 40121 will not be higher than the upper surface of the top wall 401, thereby ensuring the flatness of the upper surface of the top wall 401, which is beneficial to the subsequent assembly of other components and avoids interference between the welding protrusion and other components during the assembly process.

[0065] Specifically, the thickness of the sealing plate 5 and the groove depth of the first groove section 40121 are related to the thickness of the top wall 401. When designing the thickness of the sealing plate 5 and the groove depth of the first groove section 40121, they can be adjusted according to the thickness of the top wall 401. In the embodiment of the present application, the thickness of the sealing plate 5 and the groove depth of the first groove section 40121 are not specifically limited.

[0066] Specifically, when the thickness of the sealing plate 5 is 0.2 mm less than the groove depth of the first groove section 40121, the height of the protrusion at the welding point between the sealing plate 5 and the first groove section 40121 should be less than 0.2 mm; when the thickness of the sealing plate 5 is 0.4 mm less than the groove depth of the first groove section 40121, the height of the protrusion at the welding point between the sealing plate 5 and the first groove section 40121 should be less than 0.4 mm.

[0067] In one embodiment, Figure 3 As shown, the groove depth of the first groove section 40121 is t, the thickness of the top wall 401 is T, and 0.25T≤t≤0.8T.

[0068] By controlling the ratio of the thickness of the top wall 401 and the depth of the first groove section 40121, close contact between the sealing plate 5 and the inner wall of the first groove section 40121 can be ensured, thereby improving the sealing performance. At the same time, the strength and welding sealing of the sealing plate 5 and the inner wall of the first groove section 40121 after welding can be ensured.

[0069] In one embodiment, Figure 3 As shown, a first chamfer 40111 is provided on the through hole 4011 around the top of the inner wall of the through hole 4011 , and a second chamfer 502 is provided on the sealing plate 5 around the bottom of the side wall of the sealing plate 5 .

[0070] The design of the first chamfer 40111 and the second chamfer 502 helps to guide the sealing plate 5 to be accurately installed into the through hole 4011, simplifying the assembly process, reducing the friction between the sealing plate 5 and the inner wall of the through hole 4011 during the assembly process, and facilitating the smooth installation of the sealing plate 5 into the through hole 4011.

[0071] Specifically, the first chamfer 40111 and the second chamfer 502 can be set to be an arc chamfer or a bevel chamfer, etc. In the embodiment of the present application, there is no specific restriction on the types of the first chamfer 40111 and the second chamfer 502.

[0072] In one embodiment, Figure 3 As shown, the sealing plate 5 includes a sealing plate body 503 and a plastic plate 504 . The plastic plate 504 is arranged on one side of the sealing plate body 503 , and the plastic plate 504 is located between the negative electrode tab 2 , the positive electrode tab 3 and the sealing plate body 503 .

[0073] By setting a plastic plate 504 between the negative electrode tab 2, the positive electrode tab 3 and the sealing plate body 503, the plastic plate 504 prevents the negative electrode tab 2 and the positive electrode tab 3 from directly contacting the sealing plate body 503, thereby avoiding short circuit of the battery cell. At the same time, the plastic plate 504 can improve the sealing performance between the sealing plate 5 and the top wall 401, ensure the sealing inside the battery cell, and prevent electrolyte leakage.

[0074] Specifically, the sealing plate body 503 and the plastic plate 504 can be fixed by bonding, or by injection molding or hot melting. In the embodiment of the present application, there is no specific restriction on the connection method between the sealing plate body 503 and the plastic plate 504.

[0075] Specifically, the plastic plate 504 can be made of PP material. In the embodiment of the present application, there is no specific limitation on the material of the plastic plate 504.

[0076] In one embodiment, Figure 7 As shown, it also includes a negative electrode welding bottom plate 8 and a positive electrode welding bottom plate 9, which are arranged below the top wall 401 and extend to the through hole 4011 respectively.

[0077] The positive electrode welding base plate 9 and the negative electrode welding base plate 8 are arranged below the top wall 401, and the positive electrode welding base plate 9 and the negative electrode welding base plate 8 extend to the through hole 4011. By bending the negative electrode tab 2 and the positive electrode tab 3, the negative electrode welding base plate 8 and the positive electrode welding base plate 9 are correspondingly abutted against the negative electrode tab 2 and the positive electrode tab 3. The installer can weld and fix the negative electrode welding base plate 8 and the negative electrode tab 2, and the positive electrode welding base plate 9 and the positive electrode tab 3 through the through hole 4011.

[0078] Specifically, the negative electrode welding bottom plate 8 and the negative electrode column can be fixed to the top wall 401 by riveting, and the positive electrode welding bottom plate 9 and the positive electrode column can be fixed to the top wall 401 by riveting.

[0079] Specifically, if Figure 2 As shown, a plastic part 10 is further included. The plastic part 10 is arranged between the negative electrode welding bottom plate 8, the positive electrode welding bottom plate 9 and the top wall 401. A through hole corresponding to the through hole 4011 is opened on the plastic part 10.

[0080] A plastic part 10 is provided between the positive electrode welding bottom plate 9, the negative electrode welding bottom plate 8, and the top wall 401. The plastic part 10 ensures insulation between the positive electrode welding bottom plate 9, the negative electrode welding bottom plate 8, and the top wall 401. Since a through hole corresponding to the through hole 4011 is formed in the plastic part 10, the negative electrode tab 2 and the positive electrode tab 3 can pass through the through hole of the plastic part 10 and exit through the through hole 4011.

[0081] The installation process of the battery cell in this embodiment is described as follows:

[0082] First, place the end plate on the electrode group 1 and pass the negative electrode tab 2 and the positive electrode tab 3 through the through hole of the end plate. Then fold the insulating film into a shape that matches the electrode group 1 and put the insulating film on the electrode group 1 to ensure that the insulating film is firmly fixed.

[0083] Then, the electrode group 1 is loaded into the accommodating cavity through the opening at the bottom of the shell 4, so that the negative electrode tab 2 and the positive electrode tab 3 on the electrode group 1 pass through the through hole of the plastic part 10 and the through hole 4011 on the top wall 401. When the shell 4 is received, the plastic part 10 has been installed at the lower part of the top wall 401.

[0084] After the electrode group 1 is installed in the housing 4 , the bottom plate 6 is welded to the opening so that the electrode group 1 is sealed in the housing 4 .

[0085] Next, the negative electrode tab 2 and the positive electrode tab 3 are bent into an "L" shape, and then the negative electrode tab 2 is welded to the negative electrode welding base plate 8, and the positive electrode tab 3 is welded to the positive electrode welding base plate 9.

[0086] After the welding of the welding base plate 6 and the tab is completed, the electrolyte can be injected into the battery cell through the through hole 4011. When the injection is completed, the sealing plate 5 is covered on the through hole 4011 and the accommodating cavity is sealed to complete the assembly of the battery cell.

[0087] According to an embodiment of the present invention, on the other hand, a battery pack is provided, comprising a plurality of battery cells.

[0088] This battery pack, including the battery cell described above, has all the beneficial technical effects of the battery cell, which will not be described in detail here.

[0089] Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations shall fall within the scope defined by the appended claims.

Claims

1. A battery cell, characterized in that: include: The electrode group has a negative electrode tab and a positive electrode tab at one end; A housing is provided with an accommodating cavity for accommodating the electrode group, a through-hole is provided in the middle area of ​​the top wall of the housing, the through-hole is for the negative electrode tab and the positive electrode tab to pass through, the through-hole is provided with a stepped groove arranged around the inner wall of the through-hole, the stepped groove includes a first groove section and a second groove section arranged above and below, the size of the first groove section is larger than the size of the second groove section, and a step surface is formed at the connection between the first groove section and the second groove section; a sealing plate, covering the through hole, the bottom surface of the sealing plate abutting against the step surface, the side wall of the sealing plate being welded to the inner wall of the first groove section, and the sealing plate being provided with a liquid injection hole; The bottom plate is provided with an opening at the bottom of the shell, the bottom plate cover is provided at the opening and seals the accommodating cavity, and an explosion-proof valve is provided on the bottom plate.

2. The battery cell according to claim 1, characterized in that The length of the sealing plate is a, the length of the top wall is A, 0.5A≤a≤0.7A; The width of the sealing plate is b, the width of the top wall is B, and b≥0.3B.

3. The battery cell according to claim 1, characterized in that The liquid injection hole is located in the middle area of ​​the sealing plate.

4. The battery cell according to claim 1, characterized in that The thickness of the sealing plate is smaller than the groove depth of the first groove section, and the thickness of the sealing plate is 0.2 mm to 0.4 mm smaller than the groove depth of the first groove section.

5. The battery cell according to claim 1, characterized in that The groove depth of the first groove section is t, the thickness of the top wall is T, and 0.25T≤t≤0.8T.

6. The battery cell according to any one of claims 1 to 5, characterized in that: A first chamfer is provided on the through hole around the top of the inner wall of the through hole, and a second chamfer is provided on the sealing plate around the bottom of the side wall of the sealing plate.

7. The battery cell according to any one of claims 1 to 5, characterized in that: The sealing plate includes a sealing plate body and a plastic plate. The plastic plate is arranged 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.

8. The battery cell according to any one of claims 1 to 5, characterized in that: It also includes a negative electrode welding bottom plate and a positive electrode welding bottom plate, which are arranged below the top wall and extend to the through hole respectively.

9. A battery pack, characterized in that: include: A plurality of battery cells according to any one of claims 1 to 8.

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