Battery and assembly method thereof

Abstract

The present invention relates to the field of battery technology, and discloses a battery and an assembly method thereof, wherein the battery comprises: a shell having a first end and a second end arranged opposite to each other, the first end being configured as a first open end, the edge of the second end extending radially toward the axial direction of the shell to form an extension ring, the central area of ​​the extension ring forming a second open end, and the second open end being smaller than the first open end; a pole group assembly installed in the shell; a positive pole cover plate arranged at the first end of the shell and fixedly connected to the shell to seal the first open end; a positive pole column insulated and installed on the positive pole cover plate and electrically connected to the positive pole of the pole group assembly; a negative pole cover plate arranged at the second end of the shell and electrically connected to the negative pole of the pole group assembly, and the negative pole cover plate being fixedly connected to at least a part of the extension ring to seal the second open end. The present invention changes the traditional peripheral welding into top direct welding, which is convenient to operate, has high welding efficiency, good connection performance, increases the welding area, and has good battery performance.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to batteries and assembling methods thereof. Background Art

[0002] At present, the batteries on the market mainly include shell, electrode group, electrode column, negative electrode cover and other components. The shell and the electrode column are insulated and sealed, the electrode column and the electrode group are connected by the positive electrode connecting piece, the negative electrode cover and the electrode group are connected by the negative electrode connecting piece, and the injection hole on the negative electrode cover is also provided with a sealing cover and a sealing nail. During the battery assembly process, the positive / negative electrode connecting piece and the electrode group, the positive electrode connecting piece and the electrode column, the negative electrode connecting piece and the shell, the negative electrode cover and the negative electrode connecting piece, and the negative electrode cover and the shell are all connected by welding. Among them, the welding method between the negative electrode connecting piece, the negative electrode cover and the shell usually adopts peripheral welding, that is, the circumferential edge of the negative electrode connecting piece is abutted against the inner wall of the shell and welded at the abutment, and the circumferential edge of the negative electrode cover is abutted against the edge of the shell and welded at the abutment. During the welding process, it is necessary to weld along the circumferential edge of the negative electrode connecting piece and the circumferential edge of the negative electrode cover respectively to achieve relative fixation between the negative electrode connecting piece, the negative electrode cover and the shell.

[0003] However, the peripheral welding method has low processing efficiency, limited welding area, and poor connection performance after welding, which can easily lead to poor battery performance and cause quality problems. Summary of the invention

[0004] In view of this, the present invention provides a battery and an assembly method thereof to solve the problem that the peripheral welding method of the battery has low efficiency, small welding area and poor performance.

[0005] In the first aspect, the present invention provides a battery, comprising: a shell, having a first end and a second end arranged opposite to each other, the first end being configured as a first open end, and the second end being configured with an extension ring, the extension ring being formed by the edge of the second end extending along the radial direction of the shell toward the axial direction of the shell, the central area of ​​the extension ring forming a second open end, the second open end being smaller than the first open end; a pole group assembly, installed in the shell; a positive pole cover plate, arranged at the first end of the shell and fixedly connected to the shell to seal the first open end; a positive pole column, insulated and mounted on the positive pole cover plate and electrically connected to the positive pole of the pole group assembly; a negative pole cover plate, arranged at the second end of the shell and electrically connected to the negative pole of the pole group assembly, the negative pole cover plate being fixedly connected to at least a portion of the extension ring to seal the second open end.

[0006] Beneficial effect: by setting the second end of the shell to form an extension ring, after the electrode group assembly is loaded into the shell from the first end of the shell, the extension ring plays a supporting and limiting role for the electrode group assembly on the one hand, and also realizes overlapping with the negative electrode cover plate on the other hand. The negative electrode cover plate overlaps at least part of the area of ​​the extension ring. Compared with the traditional connection method in which the edge of the negative electrode cover plate abuts the shell, the contact area between the negative electrode cover plate and the shell is increased, and it is convenient to weld the negative electrode cover plate and the extension ring from the outside of the shell, and the traditional peripheral welding is changed to top direct welding. It is easy to assemble, has high welding efficiency, is easy to detect, is easy to operate, and increases the welding area. The connection reliability is high, which is conducive to reducing battery performance problems, improving product yield, and saving manufacturing costs.

[0007] In an optional embodiment, the shell is cylindrical, the diameter of the cross section of the shell perpendicular to its axis is D, and the extension dimension of the extension ring along the radial direction of the shell is L1, wherein 0.06≤L1 / D≤0.12.

[0008] Beneficial effect: Setting the value range of L1 / D between 0.06 and 0.12 can ensure that the extension ring itself has sufficient strength, improve stability, provide sufficient welding area, have sufficient current capacity, and improve battery performance.

[0009] In an optional embodiment, the extension ring includes a first ring portion and a second ring portion, the second ring portion is located on the inner side of the first ring portion along the radial direction of the shell, the second ring portion is higher than the first ring portion, and the negative electrode cover plate is located on the side of the second ring portion facing the outside of the shell and is welded to the second ring portion.

[0010] Beneficial effect: By setting the second ring portion of the extension ring higher than the first ring portion, and arranging the welding of the negative electrode cover plate and the second ring portion, on the one hand, it is convenient to fix the negative electrode cover plate and the extension ring, and on the other hand, it is also convenient to ensure that after the negative electrode cover plate is overlapped on the second ring portion, the lower surface of the negative electrode cover plate is flush with the lower surface of the first ring portion, thereby maintaining the flatness and beauty of the overall structural appearance and improving the stability of the battery when placed.

[0011] In an optional implementation, a dimension of the second ring portion along the radial direction of the shell is L2, wherein 0.02≤L2 / D≤0.04.

[0012] Beneficial effect: Setting the value range of L2 / D between 0.02 and 0.04 can ensure that there is sufficient flow area between the second ring portion and the negative electrode cover plate, and that there is sufficient flow area between the first ring portion and the electrode group assembly, thereby ensuring the flow capacity and improving the battery performance.

[0013] In an optional embodiment, the electrode group assembly includes: an electrode group; a positive electrode connecting plate, arranged between the electrode group and the positive electrode column, one side of the positive electrode connecting plate is electrically connected to the positive electrode of the electrode group and the other side is electrically connected to the positive electrode column; and / or, a negative electrode connecting plate, arranged between the negative electrode cover plate and the electrode group, one side of the negative electrode connecting plate is electrically connected to the negative electrode cover plate and the other side is electrically connected to the negative electrode of the electrode group.

[0014] Beneficial effects: The positive electrode connecting piece electrically connects the positive electrode column to the positive electrode of the electrode group, and the negative electrode connecting piece electrically connects the negative electrode cover plate to the negative electrode of the electrode group, with convenient connection and good stability.

[0015] In an optional embodiment, the negative electrode connecting plate includes a pole group welding area and a cover plate welding area, the cover plate welding area is arranged around the pole group welding area, the pole group welding area protrudes upward relative to the cover plate welding area, the pole group welding area is welded to the pole group, and the cover plate welding area is welded to the first ring portion.

[0016] Beneficial effect: by setting the electrode group welding area to protrude upward relative to the cover plate welding area, it is convenient to weld the electrode group welding area to the electrode group, and at the same time, it is convenient to weld the cover plate welding area to the first ring portion, and the electrical connection between the negative electrode connecting piece and the shell is realized by welding the cover plate welding area to the first ring portion, and the peripheral welding of the traditional negative electrode connecting piece is changed to the top direct welding operated from the outside of the bottom surface of the shell, which reduces the difficulty of operation and increases the welding area. At the same time, the electrical connection between the negative electrode cover plate and the shell is realized due to the welding of the negative electrode cover plate and the second ring portion on the shell, thereby realizing the electrical connection between the negative electrode connecting piece and the negative electrode cover plate, and the integrity is good, ensuring the reliable connection between the negative electrode of the electrode group and the outside world.

[0017] In an optional embodiment, the negative electrode cover plate includes: an injection area, which is arranged at the center of the negative electrode cover plate, and an injection hole is opened on the injection area; and / or, a recessed area, which is arranged around the injection area, the recessed area is lower than the injection area and is flush with the first ring portion; and / or, a raised area, which is arranged around the recessed area, the raised area is higher than the recessed area and is flush with the injection area; and / or, an overlapping area, which is arranged around the raised area, the overlapping area is lower than the raised area and is flush with the recessed area, and the overlapping area overlaps with the second ring portion.

[0018] Beneficial effects: by setting a recessed area to surround the injection area and the recessed area is lower than the injection area, the injection area is higher than the recessed area, the injection area is located relatively above the recessed area, and the injection area bulges upward relative to the recessed area, a accommodating space is formed to facilitate the installation of the sealing cover plate, and while keeping the lower surface of the sealing cover plate flush with the lower surface of the entire negative electrode cover plate, the overall appearance is kept flat; by setting a raised area, it is beneficial to increase the overall strength of the negative electrode cover plate, ensure the flatness of the recessed area and the overlapping area, and the raised area is flush with the injection area, which is convenient for processing; by setting the overlapping area lower than the raised area and flush with the recessed area, it is convenient to achieve overlapping of the overlapping area with the second ring portion, and at the same time, it also ensures that the lower surface of the negative electrode cover plate is flush with the lower surface of the shell after overlapping, thereby maintaining the stability of the battery when placed.

[0019] In an optional embodiment, the wall thickness of the shell is H, and the lower surface of the injection area is higher than the lower surface of the recessed area by a distance H1, wherein 1.5≤H1 / H≤2.5;

[0020] And / or, the connecting portion between the injection area and the recessed area is an inclined annular surface arranged at an angle to the axis of the shell, and the angle between the inclined annular surface and the axis of the shell is θ, wherein 15°≤θ≤60°.

[0021] Beneficial effect: Setting the value range of H1 / H between 1.5 and 2.5 is not only convenient for molding, but also can maintain sufficient strength and increase volume utilization;

[0022] And / or, the side of the inclined annular surface facing the outside of the shell is convenient for providing guidance for the sealing cover plate during the installation of the sealing cover plate, has a certain positioning and guiding effect, and is convenient for the installation of the sealing cover plate; the angle θ between the inclined annular surface and the axis of the shell is between 15° and 60°, which is convenient for positioning and installation of the sealing cover plate and convenient for processing.

[0023] In an optional embodiment, the battery further comprises: a sealing cover plate, wherein the sealing cover plate is arranged in the liquid injection area to seal the liquid injection hole.

[0024] Beneficial effect: By arranging a sealing cover plate in the liquid injection area, the liquid injection hole can be sealed, thereby ensuring the sealing of the battery.

[0025] In an optional embodiment, the positive electrode cover plate includes a cover plate body, a groove ring portion and an edge ring portion which are connected in sequence from the inside to the outside along its radial direction, the cover plate body is flush with the edge ring portion, the groove ring portion is recessed downward relative to the cover plate body and the edge ring portion, a mounting hole is constructed on the cover plate body, the positive electrode column is passed through the mounting hole, the side wall of the groove ring portion facing the side of the shell abuts against the inner wall of the shell, and the lower surface of the edge ring portion abuts against the upper end surface of the shell, wherein the radial dimension of the edge ring portion along the positive electrode cover plate is L3, the lower surface of the groove ring portion is H3 lower than the lower surface of the edge ring portion, L3=H, 1.2≤H3 / H≤2.5.

[0026] Beneficial effect: by arranging a groove ring portion on the positive electrode cover plate that is recessed downward relative to the cover plate body and the edge ring portion, the groove ring portion is close to the edge position of the positive electrode cover plate, when the positive electrode cover plate is installed to the first open end of the shell, the lower surface of the edge ring portion abuts against the upper end of the shell, thereby realizing axial limitation of the positive electrode cover plate, and at the same time, the side wall of the groove ring portion close to the edge of the positive electrode cover plate abuts against the inner wall of the shell, further increasing the radial limitation between the positive electrode cover plate and the shell, and increasing the relative stability between the two, and the side wall of the groove ring portion is welded to the shell, and the edge The ring portion is welded to the upper end of the shell, the welding area is increased, the connection strength is high, and the stability is good; by setting the radial dimension L3 of the edge ring portion along the positive cover plate to be equal to the wall thickness H of the shell, the edge ring portion is directly overlapped on the upper end of the shell, and when the side wall of the groove ring portion abuts the inner wall of the shell, it can be ensured that the outer edge of the positive cover plate is exactly flush with the outer side wall of the shell, so that the overall appearance is smooth and tidy, avoiding unnecessary damage; setting the ratio of H3 to H to a value between 1.2 and 2.5 is not only convenient for processing and forming, but also can reduce the size of the battery in the up and down directions.

[0027] In a second aspect, the present invention also provides a battery assembly method, which is used to assemble the above-mentioned battery, and the battery assembly method includes: welding the electrode group in the electrode group assembly to the negative electrode connecting piece to form a first assembly; loading the first assembly into the shell from the first open end of the shell; welding the negative electrode connecting piece to the first ring portion on the extension ring from the side of the extension ring toward the outside of the shell; loading the positive electrode connecting piece in the electrode group assembly into the shell from the first open end and welding it to the electrode group; installing the positive electrode cover plate to the first open end and welding it to the shell; installing the positive electrode column into the mounting hole on the positive electrode cover plate, and welding the positive electrode column to the positive electrode connecting piece; installing the negative electrode cover plate to the second open end of the shell, and welding the negative electrode cover plate to the second ring portion on the extension ring from the side of the negative electrode cover plate toward the outside of the shell; installing the sealing cover plate to the injection hole on the negative electrode cover plate, and welding the sealing cover plate to the negative electrode cover plate.

[0028] Beneficial effects: By changing the connection method between the negative electrode cover plate and the shell, and the negative electrode connecting plate and the shell from traditional peripheral welding to top direct welding, it is easy to assemble and optimize the welding process, easy to operate, good welding effect, increased welding area, improved product performance, increased product yield, and is conducive to saving product costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the specific implementation methods of the present invention 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 present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 This is a schematic diagram of the structure of the battery before improvement;

[0031] Figure 2 A schematic diagram of the structure of a battery according to an embodiment of the present invention;

[0032] Figure 3 for Figure 2 A top view of the battery shown;

[0033] Figure 4 for Figure 3 Sectional view in the AA direction;

[0034] Figure 5 for Figure 4 A is a partial enlarged schematic diagram;

[0035] Figure 6 for Figure 4 A partial enlarged schematic diagram of B in the middle;

[0036] Figure 7 It is a schematic structural diagram of a housing according to an embodiment of the present invention;

[0037] Figure 8 for Figure 7 A view of the second end of the housing shown;

[0038] Fig. 9 for Figure 8 Cross-sectional view in the BB direction;

[0039] Fig.10 for Fig. 9 A partial enlarged schematic diagram of C in the middle;

[0040] Fig.11 is a cross-sectional view of a negative electrode cover plate according to an embodiment of the present invention;

[0041] Fig.12 for Fig.11 A partial enlarged schematic diagram of D in the middle;

[0042] Fig.13 A schematic diagram of the structure of a negative electrode connecting piece according to an embodiment of the present invention;

[0043] Fig.14 for Fig.13 A bottom view of the negative electrode connecting piece shown;

[0044] Fig.15 for Fig.14 Cross-sectional view in CC direction;

[0045] Fig.16 A schematic structural diagram of a positive electrode cover plate according to an embodiment of the present invention;

[0046] Fig.17 for Fig.16 A top view of the positive electrode cover shown;

[0047] Fig.18 for Fig.17 Cross-sectional view in the middle DD direction;

[0048] Fig.19 for Fig.18 A partial enlarged schematic diagram of middle E;

[0049] Fig. 20 FIG. 4 is a flow chart of a battery assembly method according to an embodiment of the present invention.

[0050] Description of reference numerals:

[0051] 1. Shell; 101. Extension ring; 1011. First ring portion; 1012. Second ring portion; 2. Electrode group; 3. Positive electrode connecting piece; 301. Positive electrode connecting piece body; 302. Connecting portion; 4. Negative electrode connecting piece; 401. Electrode group welding area; 402. Cover plate welding area; 403. Clearance hole; 5. Positive electrode column; 6. Negative electrode cover plate; 601. Liquid injection area; 6011. Liquid injection hole; 602. Depression Area; 603, raised area; 604, overlapping area; 605, inclined annular surface; 7, sealing cover; 8, insulating seal; 801, upper plastic; 802, lower plastic; 803, sealing ring; 9, sealing nail; 10, positive cover; 1001, cover body; 1002, groove ring; 1003, edge ring; 1004, mounting hole; 1005, raised part; 1006, explosion-proof notch. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution 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 described embodiments 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 creative work are within the scope of protection of the present invention.

[0053] like Figure 1 As shown, it is a schematic diagram of the structure of the battery currently on the market. The battery mainly includes components such as a shell, an electrode group, a pole, a positive electrode connecting piece, a negative electrode connecting piece, a negative electrode cover, a sealing cover and a sealing nail. The shell and the pole are insulated and sealed by setting an upper plastic 801, a lower plastic 802 and a sealing ring 803. There are many assembly processes and the cost is high. During the assembly process, the positive and negative electrode connecting pieces and the pole group, the positive electrode connecting piece and the pole, the negative electrode connecting piece and the shell, the negative electrode cover and the shell, and the negative electrode cover and the shell are all connected by welding. For one end of the negative electrode of the battery, the negative electrode and the negative electrode connecting piece are laser welded after the pole group is put into the shell, and the negative electrode connecting piece is laser welded to the shell, and then the negative electrode cover and the shell are laser welded. The assembly process is complicated and there are many welding processes. The welding method between the negative electrode connecting piece, the negative electrode cover and the shell usually adopts peripheral welding. There are many peripheral welding processes, slow efficiency, poor performance, and it is very easy to cause poor performance and quality problems.

[0054] Combine the following Figures 2 to 20 , describing an embodiment of the present invention.

[0055] According to an embodiment of the present invention, on the one hand, a battery is provided, such as Figures 2 to 19 As shown, the battery mainly includes: a shell 1, an electrode group assembly, a positive electrode column 5 and a negative electrode cover plate 6.

[0056] Specifically, the shell 1 has a first end and a second end that are relatively arranged, the first end is configured as a first open end, and the second end is configured with an extension ring 101, the extension ring 101 is formed by the edge of the second end extending along the radial direction of the shell 1 toward the axial direction of the shell 1, and the central area of ​​the extension ring 101 forms a second open end, and the second open end is smaller than the first open end; the pole group assembly is installed in the shell 1; the positive cover plate 10 is arranged at the first end of the shell 1 and is fixedly connected to the shell 1 to seal the first open end; the positive pole column 5 is insulated and installed on the positive cover plate 10 and is electrically connected to the positive pole of the pole group assembly; the negative cover plate 6 is arranged at the second end of the shell 1 and is electrically connected to the negative pole of the pole group assembly, and the negative cover plate 6 is fixedly connected to at least a part of the extension ring 101 to seal the second open end.

[0057] In the battery using this embodiment, an extension ring 101 is formed by setting the second end of the shell 1. After the electrode group assembly is loaded into the shell 1 from the first end of the shell 1, on the one hand, the extension ring 101 supports and limits the electrode group assembly, and on the other hand, the extension ring 101 also achieves overlap with the negative electrode cover 6. The negative electrode cover 6 overlaps at least a part of the extension ring 101. Compared with the traditional connection method in which the edge of the negative electrode cover 6 abuts the shell 1, the contact area between the negative electrode cover 6 and the shell 1 is increased, and it is convenient to weld the negative electrode cover 6 and the extension ring 101 from the outside of the shell 1, and the traditional peripheral welding is changed to top direct welding. It is easy to assemble, has high welding efficiency, is easy to detect, and is convenient to operate. It also increases the welding area and has high connection reliability, which is beneficial to reducing battery performance problems, improving product yield, and saving manufacturing costs.

[0058] It should be noted that the first end refers to the Figure 2 , Figure 4 The second end is the one in the direction of "up" indicated by the arrow in the middle; Figure 2 , Figure 4 The radial direction of the housing 1 refers to the radial direction of the cross section perpendicular to the axis of the housing 1; the edge of the second end refers to the side wall of the housing 1 along the Figure 2 , Figure 4 The lowermost end in the "downward" direction indicated by the middle arrow; the extension ring 101 is connected to the second end of the shell 1 in a ring shape, and the plane where the extension ring 101 is located is perpendicular to the axis of the shell 1; the center direction of the extension ring 101 refers to the direction of the axis of the shell 1 on the plane where the extension ring 101 is located; the negative electrode cover plate 6 is electrically connected to the negative electrode of the electrode group assembly, and the negative electrode cover plate 6 becomes the negative electrode output terminal of the battery; compared with the traditional peripheral welding, the negative electrode cover plate and the extension ring 101 in this embodiment are directly welded at the top, and the welding area is doubled.

[0059] Preferably, the negative electrode cover plate 6 is welded to at least a portion of the extension ring 101 , specifically by laser penetration welding, which is easy to operate and has high reliability.

[0060] Preferably, the battery further comprises: an insulating seal 8, the insulating seal 8 having a through hole extending from top to bottom, the positive electrode column 5 being inserted into the through hole of the insulating seal 8 and abutting against the inner wall of the through hole, that is, the insulating seal 8 wraps the circumferential surface of the positive electrode column 5, the positive electrode column 5 wrapped by the insulating seal 8 is mounted on the positive electrode cover 10, and the insulating seal 8 is located between the positive electrode column 5 and the positive electrode cover 10 to achieve insulation and sealing between the positive electrode column 5 and the positive electrode cover 10. It should be noted that, for the traditional battery, the upper plastic 801, the lower plastic 802 and the sealing ring 803 are provided to achieve insulation and sealing connection between the shell and the electrode column, that is, the sealing and insulation are separated, there are many parts, the cost is high, and the assembly process is complicated and the manufacturability is poor. The insulating seal 8 of this embodiment combines sealing and insulation into one structural member, which not only improves the sealing and insulation performance, but also reduces the number of parts and reduces the assembly process, greatly saving the battery cost and improving the competitiveness of the product.

[0061] In one embodiment, the housing 1 is cylindrical, the diameter of the cross section of the housing 1 perpendicular to its axis is D, and the extension dimension of the extension ring 101 along the radial direction of the housing 1 is L1, wherein 0.06≤L1 / D≤0.12. Figure 4 , Fig.10 As shown, the battery is a cylindrical battery, and the cross section of the battery perpendicular to its axis is circular, and D is the diameter of the circle; the extension ring 101 is in the shape of a circular ring, and L1 is the difference between the outer diameter and the inner diameter of the circular ring. It should be noted that the extension size L1 of the extension ring 101 determines the area of ​​the extension ring 101. If L1 / D is less than 0.06, the size of the extension ring 101 is too small, the product is difficult to form, the dimensional stability is poor, the welding area between the negative electrode cover plate 6 and the shell 1 is insufficient, the welding strength is weak, and the flow area is insufficient; if L1 / D is greater than 0.12, the size of the extension ring 101 is too large, the flatness is difficult to ensure, the stability is poor, and it will also compress the welding area between the negative electrode connecting piece 4 and the electrode group 2 in the electrode group assembly, resulting in insufficient welding area between the negative electrode connecting piece 4 and the electrode group 2, insufficient flow area, large heat generation, and poor performance. Therefore, setting the value range of L1 / D between 0.06 and 0.12 can ensure that the extension ring 101 itself has sufficient strength, improve stability, provide sufficient welding area, have sufficient current capacity, and improve battery performance.

[0062] In one embodiment, the extension ring 101 includes a first ring portion 1011 and a second ring portion 1012, the second ring portion 1012 is located on the inner side of the first ring portion 1011 along the radial direction of the housing 1, the second ring portion 1012 is higher than the first ring portion 1011, and the negative electrode cover plate 6 is located on the side of the second ring portion 1012 facing the outside of the housing 1 and is welded to the second ring portion 1012. The inner side refers to the side pointing to the direction of the axis of the housing 1 along the radial direction; the second ring portion 1012 is higher than the first ring portion 1011 refers to the side pointing to the direction of the axis of the housing 1 along the radial direction. Figure 4 In the "up and down" direction shown, the second ring portion 1012 is located relatively above the first ring portion 1011; the outside of the housing 1 refers to the side of the housing 1 away from the electrode group 2. By setting the second ring portion 1012 of the extension ring 101 higher than the first ring portion 1011, and arranging the welding of the negative electrode cover plate 6 and the second ring portion 1012, on the one hand, it is convenient to fix the connection between the negative electrode cover plate 6 and the extension ring 101, and on the other hand, it is convenient to ensure that after the negative electrode cover plate 6 is overlapped on the second ring portion 1012, the lower surface of the negative electrode cover plate 6 is flush with the lower surface of the first ring portion 1011, thereby maintaining the flatness and beauty of the overall structure appearance and improving the stability of the battery when placed.

[0063] In one embodiment, the radial dimension of the second ring portion 1012 along the housing 1 is L2, wherein 0.02≤L2 / D≤0.04. Figure 4 , Fig.10 As shown, the second ring portion 1012 of the extension ring 101 is welded to the negative electrode cover plate 6, and the first ring portion 1011 is welded to the negative electrode connecting piece 4 in the electrode group assembly. If L2 / D is less than 0.02, the size of the second ring portion 1012 is too small, the welding area between the negative electrode cover plate 6 is small, the welding strength is weak, and the reliability is poor; if L2 / D is greater than 0.04, the size of the second ring portion 1012 is too large. When the size of the extension ring 101 is constant, the size of the first ring portion 1011 is correspondingly reduced, which will compress the welding area between the negative electrode connecting piece 4 and the shell 1, resulting in insufficient flow area between the negative electrode connecting piece 4 and the shell 1, poor flow capacity, excessive heat generation, and affecting battery performance. Therefore, setting the value range of L2 / D between 0.02 and 0.04 can ensure that there is sufficient flow area between the second ring portion 1012 and the negative electrode cover plate 6, and that there is sufficient flow area between the first ring portion 1011 and the electrode group assembly, thereby ensuring the flow capacity and improving the battery performance.

[0064] In one embodiment, the electrode group assembly includes: an electrode group 2 and a positive electrode connecting sheet 3. The positive electrode connecting sheet 3 is disposed between the electrode group 2 and the positive electrode column 5, and one side of the positive electrode connecting sheet 3 is electrically connected to the positive electrode of the electrode group 2 and the other side is electrically connected to the positive electrode column 5. The positive electrode connecting sheet 3 electrically connects the positive electrode column 5 to the positive electrode of the electrode group 2, and the connection is convenient and the stability is good.

[0065] Preferably, the positive electrode connecting sheet 3 includes a positive electrode connecting sheet body 301 and a connecting portion 302. The positive electrode connecting sheet body 301 is welded to the electrode group 2. The connecting portion 302 protrudes from the upper surface of the positive electrode connecting sheet body 301. The connecting portion 302 is suitable for being welded to the positive electrode column 5. Further preferably, a groove opening downward is constructed on the positive electrode column 5. The groove is suitable for cooperating with and electrically connecting to the connecting portion 302. The connecting portion 302 is inserted into the groove to realize the connection between the positive electrode column 5 and the positive electrode of the electrode group 2 through the positive electrode connecting sheet 3, and can reduce the occupied space in the up and down directions, thereby compressing the height dimension of the entire battery and reducing the volume of the battery. Specifically, after the connecting portion 302 is inserted into the groove of the positive electrode column 5, the positive electrode column 5 and the connecting portion 302 are laser penetrated and welded from above the positive electrode column 5 to realize a fixed connection between the positive electrode column 5 and the connecting portion 302, which is easy to operate, has low welding difficulty and high welding quality. Among them, the upper part refers to Figure 4 The arrow in the middle points to the direction of "up"; down refers to Figure 4 The arrow in the middle points to the direction of "down".

[0066] In one embodiment, the electrode group assembly further includes: a negative electrode connecting sheet 4, which is disposed between the negative electrode cover plate 6 and the electrode group 2, and one side of the negative electrode connecting sheet 4 is electrically connected to the negative electrode cover plate 6 and the other side is electrically connected to the negative electrode of the electrode group 2. The negative electrode connecting sheet 4 electrically connects the negative electrode cover plate 6 to the negative electrode of the electrode group 2, and the connection is convenient and has good stability.

[0067] In one embodiment, the negative electrode connecting sheet 4 includes an electrode group welding area 401 and a cover plate welding area 402. The cover plate welding area 402 is arranged around the electrode group welding area 401. The electrode group welding area 401 is upwardly protruded relative to the cover plate welding area 402. The electrode group welding area 401 is welded to the electrode group 2, and the cover plate welding area 402 is welded to the first ring portion 1011. The electrode group welding area 401 is upwardly protruded relative to the cover plate welding area 402. Figure 4 , Fig.11In the “up and down” direction indicated by the middle arrow, the electrode group welding area 401 is higher than the cover plate welding area 402 , that is, the electrode group welding area 401 is located relatively above the cover plate welding area 402 . The electrode group 2 is located above the extension ring 101. By setting the electrode group welding area 401 to protrude upward relative to the cover plate welding area 402, it is convenient to weld the electrode group welding area 401 to the electrode group 2, and at the same time, it is convenient to weld the cover plate welding area 402 to the first ring portion 1011. The electrical connection between the negative electrode connecting piece 4 and the shell 1 is achieved by welding the cover plate welding area 402 to the first ring portion 1011. The peripheral welding of the traditional negative electrode connecting piece 4 is changed to top direct welding operated from the outside of the bottom surface of the shell 1, which reduces the difficulty of operation and increases the welding area. At the same time, due to the welding of the negative electrode cover plate 6 and the second ring portion 1012 on the shell 1, the electrical connection between the negative electrode cover plate 6 and the shell 1 is achieved, thereby achieving the electrical connection between the negative electrode connecting piece 4 and the negative electrode cover plate 6, and the integrity is good, ensuring the reliable connection between the negative electrode of the electrode group 2 and the outside world.

[0068] In one embodiment, the negative electrode cover plate 6 includes: a liquid injection area 601, which is arranged at the center of the negative electrode cover plate 6, and a liquid injection hole 6011 is opened on the liquid injection area 601 to inject electrolyte into the battery. The negative electrode cover plate 6 also includes: a recessed area 602, which is arranged around the liquid injection area 601, the recessed area 602 is lower than the liquid injection area 601 and is flush with the first ring portion 1011, by arranging the recessed area 602 around the liquid injection area 601 and the recessed area 602 is lower than the liquid injection area 601, the liquid injection area 601 is higher than the recessed area 602, the liquid injection area 601 is located relatively above the recessed area 602, and the liquid injection area 601 is upwardly protruded relative to the recessed area 602, so as to form an accommodation space, so as to facilitate the installation of the sealing cover plate 7, and keep the lower surface of the sealing cover plate 7 flush with the lower surface of the entire negative electrode cover plate 6, so as to maintain the flatness of the overall appearance. The negative electrode cover plate 6 also includes: a raised area 603, which is arranged around the recessed area 602. The raised area 603 is higher than the recessed area 602 and is flush with the injection area 601. By setting the raised area 603, it is beneficial to increase the overall strength of the negative electrode cover plate 6, ensure the flatness of the recessed area 602 and the overlapping area 604, and the raised area 603 is flush with the injection area 601, which is easy to process. The negative electrode cover plate 6 also includes: an overlap area 604, which is arranged around the raised area 603, the overlap area 604 is lower than the raised area 603 and is flush with the recessed area 602, and the overlap area 604 overlaps with the second ring portion 1012. By setting the overlap area 604 lower than the raised area 603 and flush with the recessed area 602, it is easy to achieve the overlap between the overlap area 604 and the second ring portion 1012, and at the same time, it is ensured that the lower surface of the negative electrode cover plate 6 is flush with the lower surface of the shell 1 after the overlap, so as to maintain the stability of the battery when placed. Here, "lower than" refers to the area located at Figure 4 , Fig.11 The arrow in the middle points to the direction of "down", and above refers to the direction located Figure 4 , Fig.11 The arrow in the middle points to the direction of "up". The overlapping area 604 and the second ring portion 1012 are overlapped and then welded to achieve a fixed connection between the negative electrode cover plate 6 and the housing 1.

[0069] In one embodiment, the wall thickness of the housing 1 is H, and the lower surface of the injection area 601 is higher than the lower surface of the recessed area 602 by a distance H1, wherein 1.5≤H1 / H≤2.5. Figure 4 , Fig.10 , Fig.12 As shown, the wall thickness H of the housing 1 is as follows Fig.10 As shown in FIG. 6 , the lower surface of the injection area 601 is higher than the lower surface of the recessed area 602 by a distance H1. Fig.12 As shown, the lower surface refers to the Figure 4 , Fig.12 The surface in the direction of "down" indicated by the arrow in the middle. It should be noted that the wall thickness H of the shell 1 is a fixed value. The larger the ratio of H1 to H, the larger the value of H1. Conversely, the smaller the ratio of H1 to H, the smaller the value of H1. If H1 / H is less than 1.5, that is, H1 is less than 1.5 times the shell wall thickness, the distance between the lower surface of the injection area 601 and the lower surface of the recessed area 602 is too small, the product is not easy to form, and there is a rebound phenomenon after forming, and the size is unstable; if H1 / H is greater than 2.5, that is, H1 is greater than 1.5 times the shell wall thickness, the negative electrode cover plate 6 occupies a large space in the up and down directions, and the volume utilization rate decreases. Therefore, setting the value range of H1 / H between 1.5 and 2.5 is not only convenient for forming, but also can maintain sufficient strength and increase the volume utilization rate. Preferably, the value of H1 / H is 2.

[0070] In one embodiment, the connection portion between the injection area 601 and the recessed area 602 is an inclined annular surface 605 arranged at an angle to the axis of the housing 1, and the angle between the inclined annular surface 605 and the axis of the housing 1 is θ, wherein 15°≤θ≤60°. Fig.14 As shown in the figure, the dotted line is a straight line parallel to the axis, and the angle between the inclined annular surface 605 and the dotted line is the angle between the axis of the shell 1. By setting the connecting part between the injection area 601 and the recessed area 602 to be inclined, it is convenient for processing and forming, and the transition is smooth and the stress is small. At the same time, the inclined annular surface 605 makes the injection area 601 open to the outside of the shell 1 in a trumpet shape. The side of the inclined annular surface 605 facing the outside of the shell 1 is convenient for providing guidance for the sealing cover plate 7 during the installation process of the sealing cover plate 7, has a certain positioning and guiding effect, and is convenient for the installation of the sealing cover plate 7; the angle θ between the inclined annular surface 605 and the axis of the shell 1 is between 15° and 60°, which is convenient for the positioning and installation of the sealing cover plate 7 and convenient for processing.

[0071] In one embodiment, the battery further includes: a sealing cover plate 7, which is arranged in the liquid injection area 601 to seal the liquid injection hole 6011. After the liquid injection is completed, the liquid injection hole 6011 needs to be closed to prevent the electrolyte from flowing out and ensure the safety of the battery. By arranging the sealing cover plate 7 in the liquid injection area 601, the liquid injection hole 6011 can be sealed, thereby ensuring the sealing of the battery.

[0072] Preferably, the battery further comprises a sealing nail 9, which is inserted into the injection hole 6011 and is located on the side of the sealing cover plate 7 facing the inside of the housing 1, so as to further improve the sealing of the injection hole 6011. It should be noted that a clearance hole 403 is configured at a position corresponding to the injection hole 6011 on the negative electrode connecting sheet 4 for the sealing nail 9 to pass through.

[0073] In one embodiment, the positive electrode cover plate 10 includes a cover plate body 1001, a groove ring portion 1002 and an edge ring portion 1003 which are sequentially connected from the inside to the outside along its radial direction. The cover plate body 1001 is flush with the edge ring portion 1003, and the groove ring portion 1002 is recessed downward relative to the cover plate body 1001 and the edge ring portion 1003. A mounting hole 1004 is configured on the cover plate body 1001, and a positive electrode column 5 is passed through the mounting hole 1004. The side wall of the groove ring portion 1002 facing the side of the shell 1 abuts against the inner wall of the shell 1, and the lower surface of the edge ring portion 1003 abuts against the upper end surface of the shell 1, wherein the radial dimension of the edge ring portion 1003 along the positive electrode cover plate 10 is L3, and the lower surface of the groove ring portion 1002 is lower than the lower surface of the edge ring portion 1003 by H3, L3=H, 1.2≤H3 / H≤2.5. The radial direction of the positive electrode cover plate 10 refers to the direction perpendicular to the axis of the positive electrode cover plate 10, and the radial direction from inside to outside of the positive electrode cover plate 10 refers to the direction from the center position to the edge position of the positive electrode cover plate 10, and the cover plate body 1001 is flush with the edge ring portion 1003. The upper surface is flush with the upper surface of the cover plate body 1001 and the edge ring portion 1003; Figure 4 , Fig.18 The arrow in the middle points to the surface in the "up" direction; the lower surface refers to the surface along the Figure 4 , Fig.18 The arrow in the middle refers to the surface in the direction of "down"; the upper end surface of the housing 1 refers to the surface along the Figure 4 The surface in the “upper” direction indicated by the middle arrow is the surface of the first open end of the shell 1 ; the side wall of the groove ring portion 1002 facing the shell 1 is a side wall connecting the groove ring portion 1002 and the edge ring portion 1003 .

[0074] It should be noted that, by providing a groove ring portion 1002 on the positive cover plate 10 that is recessed downward relative to the cover plate body 1001 and the edge ring portion 1003, the groove ring portion 1002 is close to the edge position of the positive cover plate 10. When the positive cover plate 10 is installed to the first open end of the shell 1, the lower surface of the edge ring portion 1003 abuts against the upper end of the shell 1, thereby realizing axial limitation of the positive cover plate 10. At the same time, the side wall of the groove ring portion 1002 close to the edge of the positive cover plate 10 abuts against the inner wall of the shell 1, thereby further increasing the radial limitation between the positive cover plate 10 and the shell 1 and increasing the relative stability between the two. In addition, the side wall of the groove ring portion 1002 is welded to the shell 1, and the edge ring portion 1003 is welded to the upper end of the shell 1, thereby increasing the welding area, having high connection strength and good stability.

[0075] Further integration Figure 5 , Fig.10 and Fig.19 As shown, by setting the radial dimension L3 of the edge ring portion 1003 along the positive electrode cover plate 10 to be equal to the wall thickness H of the shell 1, the edge ring portion 1003 is directly overlapped on the upper end of the shell 1, and when the side wall of the groove ring portion 1002 abuts against the inner wall of the shell 1, it can ensure that the outer edge of the positive electrode cover plate 10 is exactly flush with the outer side wall of the shell 1, so that the overall appearance is smooth and tidy, avoiding unnecessary damage; the distance between the lower surface of the groove ring portion 1002 and the lower surface of the edge ring portion 1003 is H3, if H3 / H is less than 1.2, then H3 is too small, and in the "up and down" direction, the distance between the groove ring portion 1002 and the edge ring portion 1003 is too small, and the product is not easy to If H3 / H is greater than 2.5, H3 is too large, and the distance between the groove ring portion 1002 and the edge ring portion 1003 is too large. Since the positive electrode cover plate 10 and the positive electrode connecting piece 3 need to maintain sufficient spacing in the vertical direction to ensure insulation between the two, and the lower surface of the groove ring portion 1002 on the positive electrode cover plate 10 is the part closest to the positive electrode connecting piece 3, if H3 is too large, in order to ensure that there is sufficient distance between the positive electrode cover plate 10 and the positive electrode connecting piece 3, the overall height of the shell 1 will inevitably increase, so that the overall volume of the battery increases, the space utilization rate is low, and it is not conducive to the optimization of the battery size. Therefore, setting the ratio of H3 to H between 1.2 and 2.5 is not only convenient for processing and molding, but also can reduce the size of the battery in the vertical direction.

[0076] Preferably, the positive electrode cover plate 10 is further provided with an explosion-proof notch 1006, which surrounds the circumference of the mounting hole 1004 to form an explosion-proof valve. The strength of the explosion-proof notch 1006 is less than the strength of other parts of the positive electrode cover plate 10. When the air pressure in the battery is too high, the explosion-proof notch 1006 will first break to form an exhaust channel to discharge the high-temperature flue gas inside the battery to prevent the battery from exploding due to excessive internal air pressure. By providing the explosion-proof notch 1006 around the mounting hole 1004, when the explosion-proof notch 1006 breaks, the area surrounded by the explosion-proof notch 1006 can be bounced open as a whole, and the insulating seal 8 and the positive electrode column 5 installed in the mounting hole 1004 can be separated from the battery as a whole, thereby increasing the exhaust area and ensuring that the battery is disconnected from the external circuit, thereby preventing the problem of battery explosion caused by the spread of thermal runaway and improving safety performance.

[0077] Further preferably, the positive electrode cover plate 10 is configured with a raised portion 1005 protruding from the upper surface of the cover plate body 1001, and the explosion-proof notch 1006 is provided on the raised portion 1005. Figure 4 As shown, the protrusion 1005 provides radial limit for the installation of the insulating seal 8, which can increase the stability of the structure, and by setting the explosion-proof notch 1006 on the protrusion 1005, it can ensure that the explosion-proof notch 1006 is close to the circumferential edge of the insulating seal 8, and the area of ​​the area surrounded by the explosion-proof notch 1006 can be reduced as much as possible, ensuring that when the air pressure in the battery reaches the point where the explosion-proof valve needs to be opened, the explosion-proof notch 1006 can be broken in time to improve the safety of the battery. Figure 4 , Fig.15 The surface in the "up" direction indicated by the arrow.

[0078] It should be noted that the injection hole 6011 is used to inject electrolyte into the battery. The injection hole 6011 and the explosion-proof notch 1006 of the battery in the prior art are usually arranged on the same end face. When injecting liquid through the injection hole 6011, the electrolyte is very easy to splash to the explosion-proof notch 1006, causing contamination of the explosion-proof notch 1006, causing the explosion-proof notch 1006 to be punctured, thereby causing leakage, which is extremely dangerous. However, the injection hole 6011 of the present embodiment is arranged on the negative electrode cover plate 6, that is, at the end away from the positive electrode cover plate 10, so the injection hole 6011 and the explosion-proof notch 1006 on the positive electrode cover plate 10 are far away from each other, which can effectively avoid contamination of the explosion-proof notch 1006 during injection, and further ensure the safety of the battery.

[0079] According to an embodiment of the present invention, on the other hand, a battery assembly method is also provided, the battery assembly method is used to assemble the above-mentioned battery, such as Fig. 20 As shown, the battery assembly method includes the following steps:

[0080] Step S101: welding the electrode group 2 and the negative electrode connecting sheet 4 in the electrode group assembly to form a first assembly.

[0081] Specifically, one end of the electrode group 2 extends out of the negative electrode current collector, the negative electrode connecting sheet 4 is attached to the end of the electrode group 2 extending out of the negative electrode current collector, and the electrode group welding area 401 on the negative electrode connecting sheet 4 is welded to the negative electrode current collector of the electrode group 2 to achieve electrical connection between the negative electrode connecting sheet 4 and the negative electrode of the electrode group 2.

[0082] Step S102: Install the first component into the shell 1 from the first opening end of the shell 1.

[0083] It should be noted that the size of the first opening end is the same as the size of the cross section of the shell 1, which can allow the first component to pass through. After the first component is installed in the shell 1, the negative electrode connecting piece 4 is located at the end of the shell 1 away from the first opening end.

[0084] Step S103: welding the negative electrode connecting piece 4 to the first ring portion 1011 on the extension ring 101 from the side of the extension ring 101 toward the outside of the shell 1.

[0085] Specifically, the welding method between the negative electrode connecting piece 4 and the first ring portion 1011 is laser penetration welding, which is operated from the side of the extension ring 101 toward the outside of the shell 1, which is convenient for observation and control, easy to operate, and has high welding quality. By welding the negative electrode connecting piece 4 to the first ring portion 1011, the electrical connection between the negative electrode connecting piece 4 and the extension ring 101 is achieved, thereby achieving the electrical connection between the negative electrode of the electrode group 2 and the extension ring 101, that is, the electrical connection between the negative electrode of the electrode group 2 and the shell 1, and achieving the fixation of the electrode group 2 and the negative electrode connecting piece 4 relative to the shell 1, the connection stability is good, and the electrode group 2 is prevented from shaking relative to the shell 1.

[0086] Step S104: insert the positive electrode connecting piece 3 in the electrode group assembly into the housing 1 from the first opening end and weld it to the electrode group 2.

[0087] Specifically, the positive electrode current collector is extended from one end of the electrode group 2 away from the negative electrode connecting sheet 4 (i.e., the end of the electrode group 2 close to the first opening end of the shell 1 after the electrode group 2 is installed in the shell 1), and the positive electrode connecting sheet 3 is installed in the shell 1 from the first opening end and fits with the end of the positive electrode current collector extending from the electrode group 2, and then the positive electrode connecting sheet body 301 is welded to the positive electrode current collector of the electrode group 2 from above the positive electrode connecting sheet 3 by top laser penetration welding, so as to realize the electrical connection between the positive electrode connecting sheet 3 and the positive electrode of the electrode group 2, which is easy to operate and has a good welding effect.

[0088] Step S105: Install the positive electrode cover plate 10 to the first open end and weld it to the shell 1.

[0089] Specifically, the positive electrode cover plate 10 is first buckled on the first open end of the shell 1, and then the positive electrode cover plate 10 and the shell 1 are welded to achieve a fixed connection between the positive electrode cover plate 10 and the shell 1. The welding of the positive electrode cover plate 10 and the shell 1 includes welding the edge ring portion 1003 on the positive electrode cover plate 10 and the upper port of the shell 1, and welding the groove ring portion 1002 and the inner wall of the shell 1, wherein the edge ring portion 1003 overlaps the upper port of the shell 1, and the groove ring portion 1002 abuts against the inner wall portion of the shell 1 connected to the upper port, thereby increasing the contact area between the positive electrode cover plate 10 and the shell 1. Through the welding connection, the positive electrode cover plate 10 and the shell 1 are firmly connected and have good stability.

[0090] Step S106: Install the positive electrode column 5 into the installation hole 1004 on the positive electrode cover plate 10, and weld the positive electrode column 5 to the positive electrode connecting sheet 3.

[0091] Among them, the process of installing the positive electrode column 5 into the mounting hole 1004 on the positive electrode cover plate 10 specifically includes the following steps: step S201: inserting the positive electrode column 5 into the insulating seal 8 so that the insulating seal 8 wraps the circumferential surface of the positive electrode column 5; step S202: installing the positive electrode column 5 and the insulating seal 8 into the mounting hole 1004 together to realize the installation of the positive electrode column 5 on the positive electrode cover plate 10.

[0092] Specifically, the positive electrode column 5 is riveted to the positive electrode cover plate 10, and a sealing insulating member is installed between the positive electrode column 5 and the mounting hole 1004 to insulate and seal the positive electrode column 5 and the positive electrode cover plate 10; the downwardly opening groove on the positive electrode column 5 cooperates with the connecting portion 302 on the positive electrode connecting sheet 3, and the connecting portion 302 penetrates into the groove, and then laser penetration welding is performed from the top of the positive electrode column 5 to weld the positive electrode column 5 to the connecting portion 302, thereby realizing the electrical connection between the positive electrode column 5 and the positive electrode connecting sheet 3, which is easy to operate and solves the problem of difficulty in inserting the electrode group into the shell.

[0093] Step S107: Install the negative electrode cover plate 6 to the second open end of the shell 1, and weld the negative electrode cover plate 6 to the second ring portion 1012 on the extension ring 101 from the side of the negative electrode cover plate 6 facing the outside of the shell 1.

[0094] Specifically, the negative electrode cover plate 6 is used to close the second open end of the shell 1, and the negative electrode cover plate 6 is overlapped with the second ring portion 1012 of the extension ring 101 from the outside of the shell 1, and then the overlapping portion is laser penetration welded from the side of the negative electrode cover plate 6 toward the outside of the shell 1 to achieve welding of the negative electrode cover plate 6 and the shell 1. The overlapping area of ​​the negative electrode cover plate 6 and the second ring portion 1012 is at least twice as large as that of traditional peripheral welding, the welding area is increased, the connection is stable, and the top direct welding from the outside of the shell 1 is convenient for operation and observation, which optimizes the welding process, improves the manufacturability of the product, can improve the product yield, and save production costs.

[0095] It should be noted that the negative electrode cover plate 6 is welded to the second ring portion 1012 to realize the electrical connection between the negative electrode cover plate 6 and the extension ring 101. In addition, the negative electrode connecting piece 4 is welded to the first ring portion 1011 to realize the electrical connection between the negative electrode connecting piece 4 and the extension ring 101. Therefore, through the connection function of the extension ring 101, the electrical connection between the negative electrode cover plate 6 and the negative electrode connecting piece 4 is realized, and the electrical connection between the negative electrode cover plate 6 and the negative electrode of the electrode group 2 is further realized. Therefore, the negative electrode cover plate 6 can be used as the negative output terminal of the battery. When executing the above step S107, the second end of the shell 1 can be placed upward to facilitate the installation of the negative electrode cover plate 6 and the operation of the welding process, wherein the battery assembly process is completed on the operating platform, and the second end of the shell 1 facing upward means that the second end is facing away from the operating platform.

[0096] Step S108: Install the sealing cover plate 7 to the injection hole 6011 on the negative electrode cover plate 6, and weld the sealing cover plate 7 to the negative electrode cover plate 6.

[0097] Specifically, the sealing cover plate 7 is first installed in the liquid injection area 601 of the negative electrode cover plate 6, and then the sealing cover plate 7 and the liquid injection area 601 are welded to close the liquid injection hole 6011. During the welding process, the operation can be performed from the side of the sealing cover plate 7 away from the liquid injection area 601. The operation is convenient and easy to observe, which is conducive to improving the welding quality.

[0098] Before the above step S108, the following steps are also included:

[0099] Step S109: injecting electrolyte into the housing 1 from the injection hole 6011 on the negative electrode cover 6. Specifically, inserting the injection nozzle into the injection hole 6011, the electrolyte is introduced into the housing 1 through the injection nozzle.

[0100] Step S110: Install the sealing nail 9 into the injection hole 6011. The sealing nail 9 is used to preliminarily seal the injection hole 6011 to increase the sealing performance at the injection hole 6011.

[0101] Through the above steps, the assembly of the battery is achieved. By changing the connection method between the negative cover plate 6 and the shell 1, and the negative connecting piece 4 and the shell 1 from traditional peripheral welding to top direct welding, it is easy to assemble and optimize the welding process. It is easy to operate, has a good welding effect, increases the welding area, improves product performance, and increases product yield, which is beneficial to saving product costs.

[0102] Although the embodiments of the present invention have been described in conjunction with 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 are all within the scope defined by the appended claims.

Claims

1. A battery, characterized in that: include: The shell has a first end and a second end which are arranged opposite to each other, the first end is configured as a first open end, and the second end is configured with an extension ring, the extension ring is formed by the edge of the second end extending along the radial direction of the shell toward the axial direction of the shell, and the central area of ​​the extension ring forms a second open end, and the second open end is smaller than the first open end; A pole group assembly is installed in the housing; A positive electrode cover plate, disposed at the first end of the shell and fixedly connected to the shell to seal the first open end; A positive electrode column, insulated and mounted on the positive electrode cover plate and electrically connected to the positive electrode of the electrode assembly; A negative electrode cover plate, disposed at the second end of the housing and electrically connected to the negative electrode of the electrode assembly, the negative electrode cover plate being fixedly connected to at least a portion of the extension ring to seal the second open end; The shell is cylindrical, the diameter of the cross section of the shell perpendicular to its axis is D, and the extension dimension of the extension ring along the radial direction of the shell is L1, wherein 0.06≤L1 / D≤0.12; The extension ring includes a first ring portion and a second ring portion, wherein the second ring portion is located on the inner side of the first ring portion along the radial direction of the shell, and the second ring portion is higher than the first ring portion, and the negative electrode cover plate is located on a side of the second ring portion facing the outside of the shell and is welded to the second ring portion; The radial dimension of the second ring portion along the shell is L2, wherein 0.02≤L2 / D≤0.04; The negative electrode cover plate comprises: a liquid injection area, which is arranged at the center of the negative electrode cover plate and has a liquid injection hole; and a recessed area, which is arranged around the liquid injection area and is lower than the liquid injection area and flush with the first ring portion.

2. The battery according to claim 1, characterized in that The pole group assembly comprises: Pole group; A positive electrode connecting piece, disposed between the electrode group and the positive electrode column, wherein one side of the positive electrode connecting piece is electrically connected to the positive electrode of the electrode group and the other side is electrically connected to the positive electrode column; And / or, a negative electrode connecting piece is arranged between the negative electrode cover plate and the electrode group, one side of the negative electrode connecting piece is electrically connected to the negative electrode cover plate and the other side is electrically connected to the negative electrode of the electrode group.

3. The battery according to claim 2, characterized in that The negative electrode connecting plate includes a pole group welding area and a cover plate welding area, the cover plate welding area is arranged around the pole group welding area, the pole group welding area protrudes upward relative to the cover plate welding area, the pole group welding area is welded to the pole group, and the cover plate welding area is welded to the first ring portion.

4. The battery according to any one of claims 1 to 3, characterized in that The negative electrode cover plate also includes: A raised area is arranged around the recessed area, wherein the raised area is higher than the recessed area and flush with the liquid injection area; And / or, an overlapping area is arranged around the raised area, the overlapping area is lower than the raised area and flush with the recessed area, and the overlapping area overlaps with the second ring portion.

5. The battery according to claim 4, characterized in that The wall thickness of the shell is H, and the lower surface of the injection area is higher than the lower surface of the recessed area by a distance H1, wherein 1.5≤H1 / H≤2.5; And / or, the connecting portion between the injection area and the recessed area is an inclined annular surface arranged at an angle to the axis of the shell, and the angle between the inclined annular surface and the axis of the shell is θ, wherein 15°≤θ≤60°.

6. The battery according to claim 5, characterized in that The battery further includes a sealing cover plate, which is disposed in the liquid injection area to seal the liquid injection hole.

7. The battery according to claim 5, characterized in that The positive electrode cover plate includes a cover plate body, a groove ring portion and an edge ring portion which are connected in sequence from the inside to the outside along its radial direction. The cover plate body is flush with the edge ring portion, and the groove ring portion is recessed downward relative to the cover plate body and the edge ring portion. A mounting hole is constructed on the cover plate body, and the positive electrode column is penetrated through the mounting hole. The side wall of the groove ring portion facing the side of the shell abuts against the inner wall of the shell, and the lower surface of the edge ring portion abuts against the upper end surface of the shell, wherein the radial dimension of the edge ring portion along the positive electrode cover plate is L3, and the lower surface of the groove ring portion is lower than the lower surface of the edge ring portion by H3, L3=H, 1.2≤H3 / H≤2.

5.

8. A battery assembly method, characterized in that: The battery assembly method is used to assemble the battery according to any one of claims 1 to 7, and the battery assembly method comprises: Welding the electrode group and the negative electrode connecting piece in the electrode group assembly to form a first assembly; Installing the first component into the housing from the first open end of the housing; Welding the negative electrode connecting piece to the first ring portion on the extension ring from the side of the extension ring toward the outside of the shell; Installing the positive electrode connecting piece in the electrode group assembly into the housing from the first opening end and welding it to the electrode group; Installing the positive electrode cover plate to the first open end and welding it to the shell; Installing the positive electrode column into the mounting hole on the positive electrode cover plate, and welding the positive electrode column to the positive electrode connecting piece; Installing the negative electrode cover plate to the second open end of the shell, and welding the negative electrode cover plate to the second ring portion on the extension ring from the side of the negative electrode cover plate facing the outside of the shell; The sealing cover plate is installed on the injection hole on the negative electrode cover plate, and the sealing cover plate is welded to the negative electrode cover plate.

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