Battery assembly method and battery

Abstract

The invention belongs to the technical field of batteries, and discloses a battery assembly method and a battery, the method comprises the following steps: S1, installing a protection end plate on a pole group; s2, the outer sides of a plurality of side faces of the pole group are coated with insulating films, and the insulating films and the protection end plates are subjected to hot melting to form pole group units; s3, installing a second cover plate module on any side of the pole group; s4, assembling the pole set provided with the second cover plate module into the battery shell; s5, a first cover plate module is installed; s6, final welding is conducted on the battery shell, the first cover plate module and the second cover plate module; s7, welding the composite pole with the first cover plate module; and S8, realizing current conduction between the composite pole and the tab. The tab on any side of the pole group is finally in current conduction with the composite pole, so that the influence of other welding procedures on the connection quality of the tab on the side and the composite pole is avoided, the tab on the side extends out of the battery shell and is in current conduction with the composite pole, the occupation of the internal space is reduced, and the space utilization rate is high.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a battery assembly method and a battery. Background Art

[0002] The traditional assembly process of blade batteries is usually to first install the pole assembly into the battery casing, then weld the pole to the pole ear of the corresponding polarity, and then install the lower plastic and plain aluminum plate in sequence, and make a part of the pole pass through the lower plastic and plain aluminum plate and extend out of the battery casing. After the assembly of the plain aluminum plate is completed, weld the plain aluminum plate to the battery casing, and then install the upper plastic, seal and rivet block in sequence on the outside of the plain aluminum plate corresponding to the protruding part of the pole, and complete the welding of the rivet block and the plain aluminum plate, as well as riveting the rivet block to the pole extending out of the plain aluminum plate, thereby completing the assembly of the blade battery.

[0003] However, for blade batteries assembled using this method, on the one hand, it is necessary to complete the welding of the pole lugs and the poles first, and then complete the welding of the bare aluminum plate and the battery casing, the welding of the rivet block and the bare aluminum plate, and the riveting of the rivet block and the poles. As a result, the already welded pole lugs and poles will be affected by adverse factors such as high temperature and vibration during the welding of the bare aluminum plate and the battery casing, the welding of the rivet block and the bare aluminum plate, and the riveting of the rivet block and the poles, thereby reducing the welding quality between the poles and the pole lugs and reducing the product yield. On the other hand, since this method also requires that space be reserved inside the battery casing for accommodating the poles and connecting the poles with the pole lugs, the pole lugs and poles will occupy a larger space inside the battery casing, limiting the volume of the pole group and resulting in a low energy density. Summary of the invention

[0004] The object of the present invention is to provide a battery assembly method and a battery with higher product yield and energy density.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] On the one hand, a battery assembly method is provided, wherein the battery assembled by the battery assembly method comprises a battery housing, an electrode group, a first cover plate module, a composite electrode column, a protective end plate and a second cover plate module;

[0007] The battery assembly method comprises the following steps:

[0008] S1, the electrode group includes a first surface and a second surface with electrode ears, and a plurality of side surfaces perpendicular to the first surface and the second surface, the protective end plate is provided with a first penetration structure, the protective end plate is installed on the first surface and / or the second surface of the electrode group, and the electrode ears pass through the first penetration structure;

[0009] S2, coating the outer side of the electrode group with an insulating film so that the insulating film is coated on the outer sides of the plurality of side surfaces, and hot-melting the insulating film and the protective end plate to form an electrode group unit;

[0010] S3, the second cover plate module includes an independent pole, and the second cover plate module is installed on any one of the two sides of the pole group provided with the pole lug, and the pole lug on this side passes through the first penetration structure and is welded to the independent pole;

[0011] S4, the battery casing is a double-sided open structure with a cavity, the electrode group unit equipped with the second cover plate module is installed in the cavity of the battery casing, the second cover plate module closes the opening on one side of the battery casing, and the second cover plate module is pre-welded to the battery casing through a plurality of first pre-welding points arranged at intervals;

[0012] S5, the first cover plate module includes a second penetration structure for the tab to extend and a first insulating layer for isolating the first cover plate module from the tab, the first cover plate module is assembled into the opening on the other side of the battery housing, the tab passing through the first penetration structure passes through the second penetration structure, and the first cover plate module and the battery housing are pre-welded at a plurality of second pre-welding points arranged at intervals;

[0013] S6, final welding the battery housing, the first cover plate module and the second cover plate module;

[0014] S7, a receiving groove is further provided on a side of the first cover plate module away from the electrode group, the composite electrode is installed in the receiving groove, and the composite electrode is welded to the first cover plate module;

[0015] S8. Enable current conduction between the composite pole and the pole lug.

[0016] Optionally, in step S2, the following steps are also included:

[0017] S21, the battery further includes at least one protective side plate, and at least one protective side plate is pre-heat-fused to a set position of the insulating film;

[0018] S22, covering the plurality of side surfaces of the electrode group with the insulating film, and making at least one of the protective side plates cover one of the side surfaces of the electrode group;

[0019] S23, hot-melt the overlapping area between the insulating film and the protective end plate.

[0020] Optionally, in step S21, the following steps are also included:

[0021] S211, opening a positioning hole at a set position of the insulating film;

[0022] S212, a positioning structure cooperating with the positioning hole is provided on the protective side plate, the protective side plate is arranged at a set position of the insulating film, and the positioning structure is aligned with the positioning hole;

[0023] S213, hot-melt the assembled protective side plate and the insulating film.

[0024] Optionally, in step S23, the following steps are also included:

[0025] S231, pre-installing the first cover plate module and / or the second cover plate module on a side of the protective end plate away from the pole group;

[0026] S232, measuring the distance L1 between the insulating film and the first cover module, and / or the second cover module and the nearest point therebetween, and determining whether L1 satisfies 0.5 mm ≤ L1 ≤ 3 mm, if yes, executing step S233, if not, executing step S234;

[0027] S233, after removing the pre-installed first cover plate module and / or the second cover plate module, hot-melt the overlapping area between the insulating film and the protective end plate to form the pole group unit;

[0028] S234, after removing the pre-installed first cover module and / or the second cover module, cutting the insulating film, and after the cutting is completed, executing step S231.

[0029] Optionally, a plurality of thermal melting points are arranged at intervals in the overlapping region between the insulating film and the protective end plate, and the distance between the boundary of each thermal melting point away from the electrode group and the boundary of the overlapping region away from the electrode group is L2, and satisfies 0.5mm≤L2≤3mm;

[0030] And / or, the distance between the boundary of each of the thermal melting points facing the pole group side and the boundary of the overlapping area facing the pole group side is L3, and satisfies 0.5mm≤L3≤3mm.

[0031] Optionally, the first cover plate module includes a cover plate body and the first insulating layer;

[0032] The receiving groove is provided on the cover body, and the cover body is also provided with a plug-in through hole provided in the receiving groove;

[0033] The first insulating layer is injection molded on the cover body and includes an upper insulating portion, a lower insulating portion and a plug-in portion. The upper insulating portion is arranged on a side of the cover body away from the pole group and is located in the accommodating groove. The lower insulating portion is arranged on a side of the cover body facing the pole group and is located between the cover body and the protective end plate. The plug-in portion is inserted in the plug-in through hole and is used to connect the upper insulating portion and the lower insulating portion. The second through-structure penetrates the upper insulating portion, the plug-in portion and the lower insulating portion and is connected to the first through-structure.

[0034] Optionally, in step S7, the following steps are also included:

[0035] S71, a mounting groove is further formed on a side of the upper insulating portion away from the cover body, and the battery further comprises a connecting piece, and the connecting piece is installed in the mounting groove;

[0036] S72, bending the portion of the electrode tab extending out of the second penetrating structure, and welding the bent electrode tab to the connecting sheet;

[0037] S73, the battery further includes a sealing ring, and the sealing ring is installed in the receiving groove;

[0038] S74, placing the composite pole into the receiving groove, wherein the sealing ring is sandwiched between the composite pole and the first cover plate module;

[0039] S75, welding the composite pole and the first cover plate module.

[0040] Optionally, in step S8, the following steps are also included:

[0041] S81, a connecting boss protruding along the side of the connecting piece facing the composite pole is provided, and the composite pole is pre-welded and positioned on the connecting boss through a plurality of third pre-welding points arranged at intervals;

[0042] S82, fully welding the composite pole and the connecting boss.

[0043] Optionally, in step S75, the following steps are also included:

[0044] S751, the composite pole comprises a pole body, a welding ring and a second insulating layer for realizing an insulating connection between the pole body and the welding ring, the welding ring being pre-welded and positioned in the receiving groove through a plurality of fourth pre-welding points arranged at intervals;

[0045] S752, fully weld the welding ring in the receiving groove.

[0046] On the other hand, a battery is provided, wherein the battery is assembled using any of the battery assembly methods described above.

[0047] Beneficial effects of the present invention:

[0048] The present invention provides a battery assembly method, by arranging a first cover plate module with a second penetration structure on any side of a pole group provided with a pole ear, so that the pole ear on this side can achieve current conduction with a composite pole located outside the battery shell by extending out of a battery shell, thereby eliminating the space occupied by the pole ear on one side being connected to the composite pole and the composite pole extending into the battery shell, thereby reducing the occupation of the internal space and improving the utilization rate of the space on the one hand, and providing space for increasing the pole group and improving the energy density on the other hand, and arranging a protective end plate with a first penetration structure on the first surface of the pole group provided with the pole ear and / or the second surface, so as to gather and support the pole ear, avoid the pole ear from being skewed, and ensure the reliability of the structure. In addition, when the battery assembly method realizes current conduction between the pole ear on this side and the composite pole, the sequence is located after the welding of the first cover plate module and the battery shell and the welding of the composite pole and the first cover plate module, thereby effectively avoiding the influence of other welding processes on the connection quality between the pole ear and the composite pole that have achieved current conduction, thereby having a higher product yield.

[0049] The present invention also provides a battery, which is assembled by applying the above-mentioned battery assembly method, so that the volume of the electrode group can be further increased, thereby improving the energy density of the battery and increasing the power supply capacity of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 is a flow chart of a battery assembly method provided by the present invention;

[0051] Figure 2 is a structural exploded view of the battery provided by the present invention;

[0052] Figure 3 is a structural cross-sectional view of the first cover plate module side of the battery provided by the present invention;

[0053] Figure 4 It is a schematic diagram of the structure of hot melting of the insulating film and the protective side plate in the battery provided by the present invention;

[0054] Figure 5 It is a schematic diagram of the distribution of hot melting points of the protective end plate and the insulating film in the battery provided by the present invention;

[0055] Figure 6 yes Figure 5 A magnified view of the structure of part A;

[0056] Figure 7It is a schematic diagram of the distribution of pre-welding points between the first cover plate module and the battery shell in the battery provided by the present invention;

[0057] Figure 8 is an assembly diagram of the second cover plate module in the battery provided by the present invention;

[0058] Fig. 9 is a structural cross-sectional view of the second cover plate module in the battery provided by the present invention;

[0059] Fig.10 It is a schematic diagram of the structure of the cover plate body in the battery provided by the present invention;

[0060] Fig.11 It is a schematic structural diagram of the first insulating layer in the battery provided by the present invention;

[0061] Fig.12 It is a structural schematic diagram of a protective end plate in a battery provided by the present invention.

[0062] In the figure:

[0063] 100, second pre-welding point;

[0064] 1. Battery casing;

[0065] 2. pole group; 21. pole ear; 22. first surface; 23. second surface; 24. side surface;

[0066] 3. First cover plate module; 31. Cover plate body; 311. Accommodating groove; 312. Insertion through hole; 32. First insulating layer; 321. Upper insulating part; 322. Lower insulating part; 323. Insertion part; 324. Mounting groove; 325. Second penetration structure;

[0067] 4. Composite pole; 41. Pole body; 42. Welding ring; 43. Second insulating layer;

[0068] 5. Protective end plate; 51. First penetration structure; 52. Plastic structure;

[0069] 6. Second cover plate module; 61. Independent pole; 62. Light aluminum plate; 63. First plastic part; 64. Second plastic part; 65. Sealing part; 66. Riveting block;

[0070] 7. Insulating film; 71. Positioning hole; 72. Thermal melting point;

[0071] 8. Protective side panels;

[0072] 9. Connecting piece; 91. Connecting boss;

[0073] 10. Sealing ring. DETAILED DESCRIPTION

[0074] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0075] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0076] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0077] In the description of this embodiment, the terms "upper", "lower", "right", etc., directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0078] In order to improve product yield, reduce additional space occupation, and improve space utilization and energy density, the present embodiment provides a battery assembly method, and the battery assembled by the battery assembly method includes a battery casing 1, an electrode group 2, a first cover plate module 3, a composite electrode 4, a protective end plate 5 and a second cover plate module 6.

[0079] like Figures 1 to 12 As shown, the battery assembly method includes the following steps:

[0080] S1, the pole group 2 includes a first surface 22 and a second surface 23 provided with pole ears 21, and a plurality of side surfaces 24 perpendicular to the first surface 22 and the second surface 23, a first penetration structure 51 is provided on the protective end plate 5, the protective end plate 5 is installed on the first surface 22 and / or the second surface 23 of the pole group 2, and the pole ears 21 pass through the first penetration structure 51;

[0081] S2, coating the outer side of the electrode group 2 with an insulating film 7, so that the insulating film 7 is coated on the outer sides of multiple side surfaces 24, and hot-melting the insulating film 7 and the protective end plate 5 to form an electrode group unit;

[0082] S3, the second cover plate module 6 includes an independent pole 61, and the second cover plate module 6 is installed on any one side of the two sides of the pole lug 21 of the pole group 2, and the pole lug 21 on this side passes through the first penetration structure 51 and is welded to the independent pole 61;

[0083] S4, the battery housing 1 is a double-sided open structure with a cavity, the electrode group unit equipped with the second cover module 6 is installed in the cavity of the battery housing 1, the second cover module 6 closes the opening on one side of the battery housing 1, and the second cover module 6 and the battery housing 1 are pre-welded at a plurality of first pre-welding points arranged at intervals;

[0084] S5, the first cover plate module 3 includes a second penetration structure 325 for the pole ear 21 to extend out and a first insulating layer 32 for isolating the first cover plate module 3 from the pole ear 21, the first cover plate module 3 is installed into the opening on the other side of the battery housing 1, the pole ear 21 passing through the first penetration structure 51 passes through the second penetration structure 325, and the first cover plate module and the battery housing 1 are pre-welded at a plurality of second pre-welding points 100 arranged at intervals;

[0085] S6, final welding the battery housing 1, the first cover plate module 3 and the second cover plate module 6;

[0086] S7, a receiving groove 311 is further provided on the side of the first cover plate module 3 away from the electrode group 2, and the composite pole 4 is installed in the receiving groove 311, so that the composite pole 4 is welded to the first cover plate module 3;

[0087] S8, achieving current conduction between the composite pole 4 and the pole ear 21.

[0088] The battery assembly method provides a first cover plate module 3 having a second penetration structure 325 on any side of the electrode group 2 provided with the electrode ear 21, so that the electrode ear 21 on the side can conduct the current with the composite electrode 4 located outside the battery shell 1 by extending out of the battery shell 1, thereby eliminating the need for the electrode ear 21 on one side to be connected with the composite electrode 4 and the space occupied by the composite electrode 4 extending into the battery shell 1, thereby reducing the occupation of the internal space and improving the utilization of the space on the one hand, and providing space for increasing the electrode group 2 on the other hand, improving the energy density, and the first cover plate module 3 having the electrode ear 21 on the electrode group 2 can be provided with a second penetration structure 325. A protective end plate 5 with a first through structure 51 is provided on the first surface, and / or the second surface, so as to support the pole lug 21 and prevent the pole lug 21 from being skewed, thereby ensuring the reliability of the structure. In addition, when the battery assembly method realizes current conduction between the pole lug 21 and the composite pole 4 on this side, the sequence is after the welding of the first cover plate module 3 and the battery shell 1 and the welding of the composite pole 4 and the first cover plate module 3, thereby effectively avoiding the influence of other welding processes on the connection quality between the pole lug 21 and the composite pole 4 that have already achieved current conduction, thereby having a higher product yield.

[0089] In this embodiment, both the first surface 22 and the second surface 23 of the pole group 2 are equipped with protective end plates 5 .

[0090] In this embodiment, the second cover plate module 6 is a traditional riveted cover plate, which includes, in addition to the independent pole 61, a plain aluminum plate 62, a first plastic part 63, a second plastic part 64, a seal 65 and a riveted block 66. Before assembling the battery, the second cover plate module 6, that is, the riveted cover plate, can be assembled in advance. After the assembly is completed, the pole ear 21 is directly welded to the independent pole 61 in the assembled second cover plate module 6.

[0091] The specific steps include:

[0092] Ⅰ. Using structural adhesive to bond the second plastic part 64 to the side of the bare aluminum plate 62 away from the electrode group 2;

[0093] II. Using structural adhesive to bond the first plastic part 63 to the side of the bare aluminum plate 62 facing the electrode group 2;

[0094] III. A positioning groove is provided on the side of the second plastic part 64 facing away from the plain aluminum plate 62, and the riveting block 66 is installed in the positioning groove;

[0095] IV. The independent pole includes a column part and a limiting part, and the sealing member 65 is sleeved on the column part of the independent pole 61;

[0096] V. Install the independent pole 61, and make the column part of the independent pole 61 pass through the first plastic part 63, the aluminum plate 62 and the second plastic part 64 in sequence, and finally insert it into the riveting block 66. At this time, the first plastic part 63 is clamped between the limit part of the independent pole 61 and the aluminum plate 62;

[0097] VI. Rivet the column body of the independent pole 61 to the riveting block 66 to complete the assembly of the second cover plate module 6 .

[0098] The type of the second cover plate module 6 is not limited to the traditional riveted cover plate. In other embodiments, the second cover plate module 6 can also be a traditional welded cover plate or a traditional minimalist cover plate.

[0099] In addition, when the first cover plate module 3 and the second cover plate module 6 are pre-welded with the battery casing 1, the number of the first pre-welding points and the second pre-welding points 100 can be freely set according to the needs. Taking the welding of the first cover plate module 3 and the battery casing 1 as an example, in this embodiment, since the first cover plate module 3 includes a large end face with a larger area and a small end face with a smaller area, the overlapping areas formed by different end faces and the battery casing 1 are also different, wherein on the surface with a larger area, at least three second pre-welding points 100 are set, preferably five, and on the surface with a smaller area, at least five second pre-welding points 100 are set. On the surface, at least one second pre-welding point 100 is set, preferably three. When there are multiple second pre-welding points 100, it is necessary to ensure that the multiple second pre-welding points 100 set at intervals are evenly distributed; and when the first cover plate module 3 and the second cover plate module 6 are finally welded to the battery shell 1, the first cover plate module 3 and the battery shell 1 can be finally welded first, and then the second cover plate module 6 and the battery shell 1 can be finally welded, or the first cover plate module 3 and the second cover plate module 6 can be simultaneously welded to the battery shell 1. The specific implementation method depends on the actual working environment.

[0100] Alternatively, if Figure 2 , Figure 3 , Figure 4 As shown, in step S2, the following steps are also included:

[0101] S21, the battery further includes at least one protective side plate 8, and the at least one protective side plate 8 is pre-heat-fused to a set position of the insulating film 7;

[0102] S22, covering the insulating film 7 on multiple side surfaces 24 of the electrode group 2, and making at least one protective side plate 8 cover one of the side surfaces 24 of the electrode group 2;

[0103] S23, hot-melt the overlapping area between the insulating film 7 and the protective end plate 5.

[0104] By hot-melting the protective side plate 8 on the insulating film 7 before coating the insulating film 7, the protective side plate 8 can cover one of the side surfaces 24 of the electrode group 2 when the insulating film 7 is coated on the electrode group 2, so that when the electrode group 2 is put into the shell, the multiple side surfaces 24 of the electrode group 2 are protected by the protective side plate 8 to avoid scratches when the electrode group 2 is put into the shell.

[0105] The number of the protective side plates 8 can be freely set according to the protection requirements. In the present embodiment, four protective side plates 8 are provided, corresponding to the four side surfaces 24 of the electrode group 2 one by one, so as to improve the protection performance of the electrode group 2.

[0106] Alternatively, if Figure 2 , Figure 3 , Figure 4 As shown, in step S21, the following steps are also included:

[0107] S211, opening a positioning hole 71 at a set position of the insulating film 7;

[0108] S212, a positioning structure cooperating with the positioning hole 71 is provided on the protective side plate 8, the protective side plate 8 is arranged at a set position of the insulating film 7, and the positioning structure is aligned with the positioning hole 71;

[0109] S213, hot-melt the assembled protective side plate 8 and the insulating film 7.

[0110] By opening a positioning hole 71 at a set position of the insulating film 7 and providing a positioning structure that cooperates with the positioning hole 71 on the protective side plate 8, the accuracy of the hot-melt position of the protective side plate 8 can be ensured, thereby avoiding the protective side plate 8 being unable to provide effective protection when the insulating film 7 covers the pole group 2 due to inaccurate position of the protective side plate 8 after hot-melting.

[0111] Alternatively, if Figure 2 , Figure 3 , Figure 5 , Figure 6 As shown, in step S23, the following steps are also included:

[0112] S231, pre-installing the first cover plate module 3 and / or the second cover plate module 6 on the side of the protective end plate 5 away from the pole group 2;

[0113] S232, measuring the distance L1 between the closest points of the insulating film 7 and the first cover module 3 and / or the second cover module 6, and determining whether L1 satisfies 0.5 mm ≤ L1 ≤ 3 mm, if yes, executing step S233, if not, executing step S234;

[0114] S233, after removing the pre-installed first cover plate module 3 and / or the second cover plate module 6, heat-melt the overlapping area between the insulating film 7 and the protective end plate 5 to form a pole group unit;

[0115] S234, after removing the pre-installed first cover module 3 and / or second cover module 6, the insulating film 7 is trimmed, and after the trimming is completed, step S231 is executed.

[0116] By pre-installing the first cover plate module 3 and / or the second cover plate module 6 on the side of the protective end plate 5 away from the electrode group 2, and determining whether the distance dimension L1 between the pre-installed first cover plate module 3 and / or the second cover plate module 6 and the insulating film 7 satisfies the range of 0.5mm≤L1≤3mm, on the one hand, it is avoided that the distance dimension L1 between the first cover plate module 3 and / or the second cover plate module 6 and the insulating film 7 is too small, which affects the welding of the first cover plate module 3 and / or the second cover plate module 6 and the battery casing 1 and easily causes problems such as welding explosion points. On the other hand, it is avoided that the distance dimension L1 between the first cover plate module 3 and / or the second cover plate module 6 and the insulating film 7 is too large, which increases the height dimension of the protective end plate 5 and increases the manufacturing cost.

[0117] In this embodiment, since protective end plates 5 are provided at the pole ears 21 on both sides of the pole group 2, it is necessary to pre-install the first cover plate module 3 and the second cover plate module 6 in order to determine whether the distance dimension L1 between the nearest point between the first cover plate module 3 and the second cover plate module 6 and the insulating film 7 meets the set range.

[0118] In other embodiments, if the protective end plate 5 is installed at only one side of the pole ear 21 of the pole group 2 , it is preferred that the first cover plate module 3 is arranged on the side with the protective end plate 5 .

[0119] The distance dimension L1 after trimming may be any value between 0.5 mm and 3 mm or a range between any two values, such as 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, etc.

[0120] Alternatively, if Figure 2 , Figure 3 , Figure 5 , Figure 6 As shown, a plurality of spaced-apart thermal melting points 72 are provided in the overlapping area between the insulating film 7 and the protective end plate 5, and the distance between the boundary of each thermal melting point 72 away from the pole group 2 and the boundary of the overlapping area away from the pole group 2 is L2, and satisfies 0.5mm≤L2≤3mm.

[0121] By setting a plurality of spaced hot melting points 72, hot melting between the insulating film 7 and the protective end plate 5 is achieved, thereby ensuring that the scope of hot melting is wide enough and the firmness of hot melting is ensured. On the other hand, compared with the full hot melting method, the hot melting area is small, thereby shortening the time required for hot melting operation and improving the efficiency of hot melting operation. At the same time, by setting the distance dimension between the boundary of each hot melting point 72 away from the pole group 2 and the boundary of the overlapping area away from the pole group 2 as L2, and limiting the distance dimension L2 between the boundary of each hot melting point 72 away from the pole group 2 and the boundary of the overlapping area away from the pole group 2 to meet 0.5mm≤L2≤3mm, it is ensured that the hot melting point 72 and the boundary of the overlapping area away from the pole group 2 maintain a suitable distance, on the one hand, avoiding the insufficient operable area during hot melting due to too small a distance, and on the other hand, avoiding the loose connection of the area on the side of the hot melting point 72 away from the pole group 2 due to too large a distance.

[0122] Among them, the distance dimension L2 between the boundary of each thermal melting point 72 away from the pole group 2 and the boundary of the overlapping area away from the pole group 2 can be any value between 0.5mm and 3mm or a range between any two values, such as 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, etc.

[0123] Alternatively, if Figure 2 , Figure 3 , Figure 5 , Figure 6 As shown, the distance between the boundary of each thermal melting point 72 facing the electrode group 2 and the boundary of the overlapping area facing the electrode group 2 is L3, and satisfies 0.5 mm≤L3≤3 mm.

[0124] By setting a plurality of spaced hot melt points 72, hot melting between the insulating film 7 and the protective end plate 5 is achieved, thereby ensuring that the scope of hot melting is wide enough and the firmness of hot melting is ensured, and on the other hand, compared with the full hot melting method, the hot melting operation time is short and the hot melting operation efficiency is high. At the same time, by setting the distance dimension between the boundary of each hot melting point 72 facing the pole group 2 side and the boundary of the overlapping area facing the pole group 2 side as L3, and limiting the distance dimension L3 between the boundary of each hot melting point 72 facing the pole group 2 side and the boundary of the overlapping area facing the pole group 2 side to satisfy 0.5mm≤L3≤3mm, it is ensured that the hot melting point 72 and the boundary of the overlapping area facing the pole group 2 side maintain a suitable distance, on the one hand, avoid too small a distance, resulting in insufficient operable area during hot melting, and on the other hand, avoid too large a distance, resulting in loose connection of the area on the side of the hot melting point 72 facing the pole group 2 side.

[0125] Among them, the distance dimension L3 between the boundary of each thermal melting point 72 toward the pole group 2 side and the boundary of the overlapping area toward the pole group 2 side can be any value between 0.5mm and 3mm or a range between any two values, such as 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, etc.

[0126] Alternatively, if Figure 2 , Figure 3 , Fig.10 , Fig.11 , Fig.12 As shown, the first cover module 3 includes a cover body 31 and a first insulating layer 32, a receiving groove 311 is opened on the cover body 31, and a plug-in through hole 312 is also opened on the cover body 31 and is arranged in the receiving groove 311. The first insulating layer 32 is injection molded on the cover body 31, and includes an upper insulating portion 321, a lower insulating portion 322 and a plug-in portion 323. The upper insulating portion 321 is arranged on the side of the cover body 31 away from the pole group 2 and is located in the receiving groove 311. The lower insulating portion 322 is arranged on the side of the cover body 31 facing the pole group 2 and is located between the cover body 31 and the protective end plate 5. The plug-in portion 323 is inserted in the plug-in through hole 312 and is used to connect the upper insulating portion 321 and the lower insulating portion 322. The second through-structure 325 penetrates the upper insulating portion 321, the plug-in portion 323 and the lower insulating portion 322 to communicate with the first through-structure 51.

[0127] By injection molding the first insulating layer 32 on the cover body 31, the first insulating layer 32 cooperates with the protective end plate 5 to achieve double insulation protection, thereby improving the safety and protection of the structure. In addition, by providing the first insulating layer 32 composed of an upper insulating portion 321, a lower insulating portion 322 and a plug-in portion 323, the upper insulating portion 321 is arranged on the side of the cover body 31 away from the pole group 2, the lower insulating portion 322 is arranged on the side of the cover body 31 facing the pole group 2, and the plug-in portion 323 is inserted in the cover body 31. The plug-in through hole 312 is inserted, and the second penetrating structure 325 penetrates the upper insulating portion 321, the plug-in portion 323 and the lower insulating portion 322 to be connected with the first penetrating structure 51, so that the first insulating layer 32 is used to insulate and protect both sides of the cover body 31 and the inside of the plug-in through hole 312, and isolate the pole ear 21 and the cover body 31, so as to avoid direct contact between the pole ear 21 and the cover body 31 when passing through the cover body 31, resulting in a short circuit, thereby ensuring safety and protection.

[0128] In this embodiment, in order to verify the influence of the distance dimension L1, the distance dimension L2 and the distance dimension L3 on the quality of the assembled product in the battery assembly method, as shown in Table 1, six groups of embodiments and six groups of comparative examples are provided for verification. Among them, for the distance dimension L1 between the first cover plate module 3 and the insulating film 7, the distance dimension L1 is essentially the distance between the boundary of the side of the insulating film 7 away from the pole group 2 and the surface of the cover plate body 31 facing the pole group 2; for the distance dimension L1 between the second cover plate module 6 and the insulating film 7, the distance dimension L1 is essentially the distance between the boundary of the side of the insulating film 7 away from the pole group 2 and the surface of the bare aluminum plate 62 facing the pole group 2, wherein the distance dimension L1 discussed in this test is the distance dimension L1 between the first cover plate module 3 and the insulating film 7, that is, the distance between the boundary of the cover plate body 31 and the side of the insulating film 7 away from the pole group 2.

[0129] Table 1

[0130]

[0131] In Example 1, the distance dimension L1 between the first cover plate module 3 and the insulating film 7 is set to 0.5 mm, the distance dimension L2 between the boundary of the hot melting point 72 away from the electrode group 2 and the boundary of the overlapping area away from the electrode group 2 is set to 0.5 mm, and the distance dimension L3 between the boundary of the hot melting point 72 toward the electrode group 2 and the boundary of the overlapping area toward the electrode group 2 is set to 0.5 mm. At this time, the battery is assembled according to the above data. It is verified that there is no explosion point in the peripheral weld of the shell cover. After disassembling the battery, the insulating film 7 is not damaged and does not fall off.

[0132] In Example 2, the distance L1 between the first cover plate module 3 and the insulating film 7 is set to 1 mm, the distance L2 between the boundary of the hot melting point 72 away from the electrode group 2 and the boundary of the overlapping area away from the electrode group 2 is set to 2 mm, and the distance L3 between the boundary of the hot melting point 72 toward the electrode group 2 and the boundary of the overlapping area toward the electrode group 2 is set to 2 mm. At this time, the battery is assembled according to the above data, and it is verified that there is no explosion point in the peripheral weld of the shell cover. After disassembling the battery, the insulating film 7 is not damaged and does not fall off.

[0133] In Example 3, the distance L1 between the first cover plate module 3 and the insulating film 7 is set to 1.5 mm, the distance L2 between the boundary of the hot melting point 72 away from the electrode group 2 and the boundary of the overlapping area away from the electrode group 2 is set to 1 mm, and the distance L3 between the boundary of the hot melting point 72 toward the electrode group 2 and the boundary of the overlapping area toward the electrode group 2 is set to 3 mm. At this time, the battery is assembled according to the above data, and it is verified that there is no explosion point in the peripheral weld of the shell cover. After disassembling the battery, the insulating film 7 is not damaged and has not fallen off.

[0134] In Example 4, the distance L1 between the first cover plate module 3 and the insulating film 7 is set to 2 mm, the distance L2 between the boundary of the hot melting point 72 away from the electrode group 2 and the boundary of the overlapping area away from the electrode group 2 is set to 3 mm, and the distance L3 between the boundary of the hot melting point 72 toward the electrode group 2 and the boundary of the overlapping area toward the electrode group 2 is set to 1 mm. At this time, the battery is assembled according to the above data. It is verified that there is no explosion point in the peripheral weld of the shell cover. After disassembling the battery, the insulating film 7 is not damaged and has not fallen off.

[0135] In Example 5, the distance L1 between the first cover plate module 3 and the insulating film 7 is set to 2.5 mm, the distance L2 between the boundary of the hot melting point 72 away from the electrode group 2 and the boundary of the overlapping area away from the electrode group 2 is set to 1.5 mm, and the distance L3 between the boundary of the hot melting point 72 toward the electrode group 2 and the boundary of the overlapping area toward the electrode group 2 is set to 2.5 mm. At this time, the battery is assembled according to the above data, and it is verified that there is no explosion point in the peripheral weld of the shell cover. After disassembling the battery, the insulating film 7 is not damaged and has not fallen off.

[0136] In Example 6, the distance L1 between the first cover plate module 3 and the insulating film 7 is set to 3 mm, the distance L2 between the boundary of the hot melting point 72 away from the electrode group 2 and the boundary of the overlapping area away from the electrode group 2 is set to 2.5 mm, and the distance L3 between the boundary of the hot melting point 72 toward the electrode group 2 and the boundary of the overlapping area toward the electrode group 2 is set to 1.5 mm. At this time, the battery is assembled according to the above data, and it is verified that there is no explosion point in the peripheral weld of the shell cover. After disassembling the battery, the insulating film 7 is not damaged and has not fallen off.

[0137] It can be seen from Examples 1 to 6 that when the distance dimension L1 between the first cover plate module 3 and the insulating film 7 satisfies the range of 0.5mm≤L1≤3mm, the distance dimension L2 between the boundary of the hot melting point 72 away from the electrode group 2 and the boundary of the overlapping area away from the electrode group 2 satisfies the range of 0.5mm≤L2≤3mm, and the distance dimension L3 between the boundary of the hot melting point 72 toward the electrode group 2 and the boundary of the overlapping area toward the electrode group 2 satisfies the range of 0.5mm≤L3≤3mm, the battery assembled by the battery assembly method has no explosion points in the weld around the shell cover, and after disassembling the battery, the insulating film 7 is not damaged or falls off, and has high product quality.

[0138] In comparative example 1, the distance dimension L1 between the first cover plate module 3 and the insulating film 7 is set to 0.1 mm, the distance dimension L2 between the boundary of the hot melting point 72 away from the electrode group 2 and the boundary of the overlapping area away from the electrode group 2 is set to 1 mm, and the distance dimension L3 between the boundary of the hot melting point 72 toward the electrode group 2 and the boundary of the overlapping area toward the electrode group 2 is set to 1 mm. At this time, the battery assembled according to the above data is verified to have explosion points during welding around the shell cover, and the insulating film 7 melts.

[0139] It can be seen from Comparative Example 1 that when the distance dimension L1 between the first cover module 3 and the insulating film 7 is less than the minimum value of 0.5mm≤L1≤3mm, at this time, since the insulating film 7 is close to the cover body 31, an explosion point occurs when welding the periphery of the shell cover, and since the insulating film 7 is too close to the welding position, the high temperature generated by the welding causes the insulating film 7 to melt, resulting in poor insulation protection performance of the assembled battery.

[0140] In comparative example 2, the distance L1 between the first cover plate module 3 and the insulating film 7 is set to 1 mm, the distance L2 between the boundary of the hot melting point 72 away from the electrode group 2 and the boundary of the overlapping area away from the electrode group 2 is set to 0.1 mm, and the distance L3 between the boundary of the hot melting point 72 toward the electrode group 2 and the boundary of the overlapping area toward the electrode group 2 is set to 1 mm. At this time, the battery is assembled according to the above data, and it is verified that the insulating film 7 has fallen off.

[0141] It can be seen from Comparative Example 2 that when the distance dimension L2 between the boundary of the hot melting point 72 away from the side of the electrode group 2 and the boundary of the overlapping area away from the side of the electrode group 2 is less than the minimum value of 0.5mm≤L2≤3mm, since the hot melting point 72 is close to the upper edge of the overlapping area of ​​the protective end plate 5, part of the hot melting point exceeds the upper edge of the insulating film 7, resulting in insufficient hot melting area between the insulating film 7 and the protective end plate 5, which causes the problem of the insulating film 7 falling off, resulting in poor insulation protection performance of the assembled battery.

[0142] In comparative example 3, the distance dimension L1 between the first cover plate module 3 and the insulating film 7 is set to 1 mm, the distance dimension L2 between the boundary of the hot melting point 72 away from the electrode group 2 and the boundary of the overlapping area away from the electrode group 2 is set to 1 mm, and the distance dimension L3 between the boundary of the hot melting point 72 toward the electrode group 2 and the boundary of the overlapping area toward the electrode group 2 is set to 0.1 mm. At this time, the battery assembled according to the above data is verified to have a melting phenomenon between the insulating film 7 and the protective end plate 5, resulting in a short circuit.

[0143] It can be seen from Comparative Example 3 that when the distance dimension L3 between the boundary of the hot melting point 72 toward the side of the electrode group 2 and the boundary of the overlapping area toward the side of the electrode group 2 is less than the minimum value of 0.5mm≤L3≤3mm, since the hot melting point 72 is close to the lower edge of the overlapping area of ​​the protective end plate 5, part of the hot melting point 72 exceeds the lower edge of the protective end plate 5, resulting in melting through between the insulating film 7 and the protective end plate 5, thereby causing a short circuit problem, resulting in poor insulation protection performance of the assembled battery.

[0144] In comparative example 4, the distance dimension L1 between the first cover plate module 3 and the insulating film 7 is set to 4 mm, the distance dimension L2 between the boundary of the hot melting point 72 away from the electrode group 2 and the boundary of the overlapping area away from the electrode group 2 is set to 1 mm, and the distance dimension L3 between the boundary of the hot melting point 72 toward the electrode group 2 and the boundary of the overlapping area toward the electrode group 2 is set to 1 mm. At this time, the battery after assembly is completed according to the above data. It is verified that the protective end plate 5 occupies a large internal space, resulting in the compression of the volume of the electrode group 2, thereby resulting in a lower energy density of the assembled battery.

[0145] It can be seen from Comparative Example 4 that when the distance dimension L1 between the first cover plate module 3 and the insulating film 7 is greater than the maximum value of 0.5mm≤L1≤3mm, at this time, since the insulating film 7 is far away from the cover plate body 31, the protective end plate 5 occupies a large internal space. Therefore, in order to complete the assembly, it is necessary to reduce the volume of the electrode group 2, thereby reducing the energy density of the assembled battery, and the power supply capacity is poor, which does not meet the use requirements.

[0146] In comparative example 5, the distance dimension L1 between the first cover plate module 3 and the insulating film 7 is set to 1 mm, the distance dimension L2 between the boundary of the hot melting point 72 away from the electrode group 2 and the boundary of the overlapping area away from the electrode group 2 is set to 4 mm, and the distance dimension L3 between the boundary of the hot melting point 72 toward the electrode group 2 and the boundary of the overlapping area toward the electrode group 2 is set to 1 mm. At this time, the battery is assembled according to the above data. It is verified that the insulating film 7 is located in the area between the hot melting point 72 and the upper edge of the overlapping area of ​​the protective end plate 5, and is not tightly connected to the protective end plate 5, resulting in flanging of the insulating film 7.

[0147] It can be seen from Comparative Example 5 that when the distance dimension L2 between the boundary of the hot melting point 72 away from the side of the pole group 2 and the boundary of the overlapping area away from the side of the pole group 2 is greater than the maximum value of 0.5mm≤L2≤3mm, since the hot melting point 72 is far away from the upper edge of the overlapping area of ​​the protective end plate 5, the insulating film 7 is located in the area between the hot melting point 72 and the upper edge of the overlapping area of ​​the protective end plate 5, and is not tightly connected to the protective end plate 5, resulting in the insulating film 7 being flanging, which does not meet the use requirements.

[0148] In comparative example 6, the distance dimension L1 between the first cover plate module 3 and the insulating film 7 is set to 1 mm, the distance dimension L2 between the boundary of the hot melting point 72 away from the electrode group 2 and the boundary of the overlapping area away from the electrode group 2 is set to 1 mm, and the distance dimension L3 between the boundary of the hot melting point 72 toward the electrode group 2 and the boundary of the overlapping area toward the electrode group 2 is set to 4 mm. At this time, the battery is assembled according to the above data. It is verified that the insulating film 7 is located in the area between the hot melting point 72 and the lower edge of the overlapping area of ​​the protective end plate 5, and is not tightly connected to the protective end plate 5. There is a gap between the insulating film 7 and the electrode group 2.

[0149] It can be seen from Comparative Example 6 that when the distance dimension L3 between the boundary of the hot melting point 72 toward the pole group 2 and the boundary of the overlapping area toward the pole group 2 is greater than the maximum value of 0.5mm≤L3≤3mm, since the hot melting point 72 is far away from the lower edge of the overlapping area of ​​the protective end plate 5, the insulating film 7 is located in the area between the hot melting point 72 and the lower edge of the overlapping area of ​​the protective end plate 5, and is not tightly connected to the protective end plate 5, thereby weakening the strength of the insulating film 7 to wrap the pole group 2, resulting in easy generation of gaps between the insulating film 7 and the pole group 2, which does not meet the use requirements.

[0150] Alternatively, if Figure 2 , Figure 3 , Fig.10 , Fig.11 , Fig.12 As shown, in step S7, the following steps are also included:

[0151] S71, a mounting groove 324 is further provided on a side of the upper insulating portion 321 away from the cover body 31, and the battery further includes a connecting piece 9, and the connecting piece 9 is installed in the mounting groove 324;

[0152] S72, bending the portion of the electrode tab 21 extending out of the second penetrating structure 325, and welding the bent electrode tab 21 to the connecting sheet 9;

[0153] S73, the battery further includes a sealing ring 10, and the sealing ring 10 is installed in the receiving groove 311;

[0154] S74, the composite pole 4 is placed in the receiving groove 311, and the sealing ring 10 is sandwiched between the composite pole 4 and the first cover plate module 3;

[0155] S75 , welding the composite pole 4 and the first cover plate module 3 .

[0156] By providing the connecting piece 9 and welding the pole ear 21 to the connecting piece 9, the position of the pole ear 21 can be fixed in advance by using the connecting piece 9, thereby ensuring the accuracy of the position of the pole ear 21 during subsequent operations and avoiding the pole ear 21 from moving and affecting the conduction effect of the current between the pole ear 21 and the composite pole 4.

[0157] Alternatively, if Figure 3 As shown, in step S8, the following steps are also included:

[0158] S81, a connecting boss 91 is provided on one side of the connecting piece 9 facing the composite pole 4 and protrudes along the composite pole 4, and the composite pole 4 is pre-welded and positioned on the connecting boss 91 through a plurality of third pre-welding points arranged at intervals;

[0159] S82, fully weld the composite pole 4 and the connecting boss 91.

[0160] By providing a connecting boss 91 on the side of the connecting piece 9 facing the composite pole 4, it is convenient to weld the connecting piece 9 to the composite pole 4. The size and shape of the connecting boss 91 can be freely set according to demand, and it is sufficient to ensure that there is a sufficient welding area between the connecting boss 91 and the composite pole 4. In this embodiment, the connecting boss 91 is a truncated cone.

[0161] In addition, the composite pole 4 is first pre-welded to the connecting boss 91 through a plurality of third pre-welding points arranged at intervals, so as to ensure that the relative position between the composite pole 4 and the connecting boss 91 is preliminarily positioned before full welding, thereby ensuring the accuracy of the position of the two after welding during full welding, ensuring the welding quality, and even if the initial positioning is incorrect, it is convenient to separate and reposition the two, realize recycling, and reduce the scrap rate of the product.

[0162] Alternatively, if Figure 2 , Figure 3 , Fig.10 , Fig.11 , Fig.12 As shown, in step S75, the following steps are also included:

[0163] S751, the composite pole 4 includes a pole body 41, a welding ring 42 and a second insulating layer 43 for achieving an insulating connection between the pole body 41 and the welding ring 42, and the welding ring 42 is pre-welded and positioned in the receiving groove 311 through a plurality of fourth pre-welding points arranged at intervals;

[0164] S752 , fully weld the welding ring 42 into the receiving groove 311 .

[0165] First, the welding ring 42 is pre-welded in the receiving groove 311 through a plurality of fourth pre-welding points arranged at intervals, so as to ensure that the relative position of the welding ring 42 in the receiving groove 311 is positioned before full welding. Even if the initial positioning is wrong, it is convenient to separate and reposition the two, so as to achieve recycling and reduce the scrap rate of the product. The number, size and shape of the fourth pre-welding points used for pre-welding the welding ring 42 can be freely set according to actual needs. And the second insulating layer 43 is formed by injection molding process to insulate and connect the pole body 41 and the welding ring 42, so that the pole body 41, the second insulating layer 43 and the welding ring 42 form a whole. Compared with the second cover plate module 6 in the form of a traditional riveted cover plate, the separate upper insulating member and the riveting block are eliminated, thereby reducing the number of parts and simplifying the assembly process.

[0166] Alternatively, if Figure 3 As shown, a shaping structure 52 corresponding to the pole ear 21 is provided on the side of the protective end plate 5 facing the pole group 2. The shaping structure 52 is a trumpet-shaped structure whose opening gradually decreases in the direction away from the pole group 2. Thus, in step S1, the multiple converged pole ears 21 on the pole group 2 are better supported and fixed, the convergence state of the pole ears 21 is improved, and the problem of short circuit inside the battery due to poor convergence effect of the pole ears 21 is avoided.

[0167] In this embodiment, a battery is further provided, which is assembled by the above-mentioned battery assembly method. The battery is assembled by applying the above-mentioned battery assembly method, so that the volume of the electrode group 2 is further increased, thereby improving the energy density of the battery and increasing the power supply capacity of the battery.

[0168] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A battery assembly method, characterized in that: The battery assembled by the battery assembly method comprises a battery housing, an electrode group, a first cover plate module, a composite electrode column, a protective end plate and a second cover plate module; The battery assembly method comprises the following steps: S1, the electrode group includes a first surface and a second surface with electrode ears, and a plurality of side surfaces perpendicular to the first surface and the second surface, the protective end plate is provided with a first penetration structure, the protective end plate is installed on the first surface and / or the second surface of the electrode group, and the electrode ears pass through the first penetration structure; S2, coating the outer side of the electrode group with an insulating film so that the insulating film is coated on the outer sides of the plurality of side surfaces, and hot-melting the insulating film and the protective end plate to form an electrode group unit; S3, the second cover plate module includes an independent pole, and the second cover plate module is installed on any one of the two sides of the pole group provided with the pole lug, and the pole lug on this side passes through the first penetration structure and is welded to the independent pole; S4, the battery casing is a double-sided open structure with a cavity, the electrode group unit equipped with the second cover plate module is installed in the cavity of the battery casing, the second cover plate module closes the opening on one side of the battery casing, and the second cover plate module is pre-welded to the battery casing through a plurality of first pre-welding points arranged at intervals; S5, the first cover plate module includes a second penetration structure for the tab to extend and a first insulating layer for isolating the first cover plate module from the tab, the first cover plate module is assembled into the opening on the other side of the battery housing, the tab passing through the first penetration structure passes through the second penetration structure, and the first cover plate module and the battery housing are pre-welded at a plurality of second pre-welding points (100) arranged at intervals; S6, final welding the battery housing, the first cover plate module and the second cover plate module; S7, a receiving groove is further provided on a side of the first cover plate module away from the electrode group, the composite electrode is installed in the receiving groove, and the composite electrode is welded to the first cover plate module; S8. Enable current conduction between the composite pole and the pole lug.

2. The battery assembly method according to claim 1, characterized in that: In step S2, the following steps are also included: S21, the battery further includes at least one protective side plate, and at least one protective side plate is pre-heat-fused to a set position of the insulating film; S22, covering the plurality of side surfaces of the electrode group with the insulating film, and making at least one of the protective side plates cover one of the side surfaces of the electrode group; S23, hot-melt the overlapping area between the insulating film and the protective end plate.

3. The battery assembly method according to claim 2, characterized in that: In step S21, the following steps are also included: S211, opening a positioning hole at a set position of the insulating film; S212, a positioning structure cooperating with the positioning hole is provided on the protective side plate, the protective side plate is arranged at a set position of the insulating film, and the positioning structure is aligned with the positioning hole; S213, hot-melt the assembled protective side plate and the insulating film.

4. The battery assembly method according to claim 2, characterized in that: In step S23, the following steps are also included: S231, pre-installing the first cover plate module and / or the second cover plate module on a side of the protective end plate away from the pole group; S232, measuring the distance L1 between the closest points of the insulating film and the first cover module, and / or the second cover module, and determining whether L1 satisfies 0.5 mm ≤ L1 ≤ 3 mm, if yes, executing step S233, if no, executing step S234; S233, after removing the pre-installed first cover plate module and / or the second cover plate module, hot-melt the overlapping area between the insulating film and the protective end plate to form the pole group unit; S234, after removing the pre-installed first cover module and / or the second cover module, cutting the insulating film, and after the cutting is completed, executing step S231.

5. The battery assembly method according to claim 2, characterized in that: A plurality of thermal melting points are arranged at intervals in the overlapping region between the insulating film and the protective end plate, and the distance between the boundary of each thermal melting point away from the electrode group and the boundary of the overlapping region away from the electrode group is L2, and satisfies 0.5mm≤L2≤3mm; And / or, the distance between the boundary of each of the thermal melting points facing the electrode group and the boundary of the overlapping area facing the electrode group is L3, and satisfies 0.5mm≤L3≤3mm.

6. The battery assembly method according to claim 1, characterized in that: The first cover plate module comprises a cover plate body and the first insulating layer; The receiving groove is provided on the cover body, and the cover body is also provided with a plug-in through hole provided in the receiving groove; The first insulating layer is injection molded on the cover body and includes an upper insulating portion, a lower insulating portion and a plug-in portion. The upper insulating portion is arranged on a side of the cover body away from the pole group and is located in the accommodating groove. The lower insulating portion is arranged on a side of the cover body facing the pole group and is located between the cover body and the protective end plate. The plug-in portion is inserted in the plug-in through hole and is used to connect the upper insulating portion and the lower insulating portion. The second through-structure penetrates the upper insulating portion, the plug-in portion and the lower insulating portion and is connected to the first through-structure.

7. The battery assembly method according to claim 6, characterized in that: In step S7, the following steps are also included: S71, a mounting groove is further formed on a side of the upper insulating portion away from the cover body, and the battery further comprises a connecting piece, and the connecting piece is installed in the mounting groove; S72, bending the portion of the electrode tab extending out of the second penetrating structure, and welding the bent electrode tab to the connecting sheet; S73, the battery further includes a sealing ring, and the sealing ring is installed in the receiving groove; S74, placing the composite pole into the receiving groove, wherein the sealing ring is sandwiched between the composite pole and the first cover plate module; S75, welding the composite pole and the first cover plate module.

8. The battery assembly method according to claim 7, characterized in that: In step S8, the following steps are also included: S81, a connecting boss protruding along the side of the connecting piece facing the composite pole is provided, and the composite pole is pre-welded and positioned on the connecting boss through a plurality of third pre-welding points arranged at intervals; S82, fully welding the composite pole and the connecting boss.

9. The battery assembly method according to claim 7, characterized in that: In step S75, the following steps are also included: S751, the composite pole comprises a pole body, a welding ring and a second insulating layer for realizing an insulating connection between the pole body and the welding ring, the welding ring being pre-welded and positioned in the receiving groove through a plurality of fourth pre-welding points arranged at intervals; S752, fully weld the welding ring in the receiving groove.

10. A battery, characterized in that The battery is assembled using the battery assembly method according to any one of claims 1 to 9.

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