Battery assembly method and battery

Abstract

The invention belongs to the technical field of batteries, and discloses a battery assembly method and a battery, and the method comprises the following steps: S1, coating a plurality of side surfaces of a pole group with insulating films; s2, a composite cover plate is arranged on the first surface of the pole group; s3, performing hot melting on the insulating film and the first insulating layer; s4, assembling the pole set with the composite cover plate on the first surface into the cavity of the composite shell; s5, the composite cover plate and the composite shell are welded; s6, welding the composite pole and the composite cover plate, and welding the composite pole and the composite shell; and S7, realizing current conduction between the composite pole and the tab. Current conduction is finally achieved through the tab and the composite pole, so that the influence of other welding procedures on the connection quality of the tab and the composite pole is avoided, and due to the fact that current conduction is achieved through the tab outside the composite shell and the composite pole, occupation of the internal space is reduced, the utilization rate of the space is increased, and the service life of the battery is prolonged. And a space is provided for enlarging the pole group, and the energy density is improved.

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 shell, then weld the pole column to the pole ear of the corresponding polarity, and then install the lower plastic and cover plate in sequence, and make a part of the pole column pass through the lower plastic and cover plate and extend out of the battery shell. After the cover plate is assembled, weld the cover plate to the battery shell, and then install the upper plastic, sealing ring and welding platform in sequence on the outer side of the cover plate corresponding to the part of the pole column, and complete the welding of the welding platform and the cover plate, as well as the welding of the welding platform and the pole column extending out of the cover 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 ear and the pole column first, and then complete the welding of the cover plate and the battery shell, the welding of the welding platform and the cover plate, and the welding of the welding platform and the pole column. As a result, the pole ear and the pole column that have been welded will be affected by adverse factors such as high temperature and vibration during the welding of the cover plate and the battery shell, the welding of the welding platform and the cover plate, and the welding of the welding platform and the pole column, thereby reducing the welding quality between the pole column and the pole ear and reducing the product yield. On the other hand, since this method also requires that the pole column and the pole ear be connected inside the battery shell, the pole ear and the pole column will occupy a larger space inside the battery shell, limiting the volume of the pole group and having a low energy density. In addition, since one side of the pole ear involves the welding of the cover plate and the battery shell, the welding of the welding platform and the cover plate, the welding of the welding platform and the pole column, and the welding of the pole ear and the pole column, a large number of welding operations are gathered on the pole ear side, resulting in adverse changes in the microstructure of the pole ear material due to the high temperature generated by a large number of welding operations, thereby affecting the electrical and mechanical properties of the pole ear itself, resulting in an increase in the resistance of the pole ear, and reducing the discharge performance and cycle life of the blade battery. Summary of the invention

[0004] The object of the present invention is to provide a battery assembly method and a battery with high space utilization, good product quality and high energy density.

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

[0006] In one aspect, a battery assembly method is provided, wherein the battery assembled by the battery assembly method comprises a composite housing, an electrode group, a composite cover plate and a composite electrode column;

[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, and an insulating film is coated on the outer sides of the plurality of side surfaces;

[0009] S2, the composite cover plate is provided with a first penetration structure for the electrode lug to extend out, the composite cover plate is installed on the first surface of the electrode group, and the electrode lug on the first surface passes through the first penetration structure;

[0010] S3, a first insulating layer for isolating the composite cover plate and the electrode lug is injection-molded on the composite cover plate, and the overlapping area between the insulating film coated on the outer side of the electrode group and the first insulating layer on the composite cover plate installed on the first surface is hot-melted;

[0011] S4, the composite housing is a single-side open structure with a cavity, a second through-structure for the pole ear to extend out is provided on the wall surface opposite to the open side, and a second insulating layer for isolating the composite housing from the pole ear is injection-molded on the wall surface, the pole assembly with the composite cover plate on the first surface is inserted into the cavity of the composite housing, and the pole ear on the second surface is passed through the second through-structure, and the composite cover plate closes the opening of the composite housing;

[0012] S5, welding the composite cover plate used for closing the opening of the composite shell to the composite shell;

[0013] S6, a first receiving groove is formed on the side of the composite cover away from the electrode group, and a second receiving groove is formed on the side of the composite shell away from the electrode group, the composite pole is installed in the first receiving groove and the second receiving groove, and the composite pole is welded to the composite cover and the composite pole is welded to the composite shell;

[0014] S7, achieving current conduction between the composite pole and the pole lug.

[0015] Optionally, in step S1, the following steps are also included:

[0016] S11, 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;

[0017] S12, 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.

[0018] Optionally, in step S11, the following steps are also included:

[0019] S111, opening a positioning hole at a set position of the insulating film;

[0020] S112, 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;

[0021] S113, hot-melt the assembled protective side plate and the insulating film.

[0022] Optionally, in step S2, the following steps are also included:

[0023] S21, pre-installing the composite cover plate on the side of the first surface away from the electrode group, and passing the electrode lug through the first penetration structure;

[0024] S22, measuring the distance L1 between the closest points of the composite cover plate and the insulating film, and determining whether L1 satisfies 0.5 mm ≤ L1 ≤ 3 mm, if yes, executing step S3, if no, executing step S23;

[0025] S23, after removing the pre-installed composite cover plate, cutting the insulating film, after the cutting is completed, executing step S21.

[0026] Optionally, a plurality of thermal melting points are arranged at intervals in the overlapping region between the insulating film and the first insulating layer, and the distance between a boundary of each thermal melting point away from the electrode group and a boundary of the overlapping region away from the electrode group is L2, and satisfies 0.5 mm ≤ L2 ≤ 3 mm;

[0027] 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.

[0028] Optionally, in step S5, the following steps are also included:

[0029] S51, pre-welding and positioning the composite cover plate and the composite shell at the openings on both sides of the composite shell through a plurality of first pre-welding points arranged at intervals;

[0030] S52, fully welding the composite cover plate and the composite shell at the open positions on both sides of the composite shell.

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

[0032] The first receiving groove is formed on the cover body, and the cover body is also provided with a first plugging through hole disposed in the first receiving groove;

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

[0034] Optionally, the composite housing comprises a housing body and the second insulating layer;

[0035] The shell body includes a first wall surface and a plurality of second wall surfaces perpendicular to the first wall surface, the plurality of second wall surfaces are arranged around the first wall surface to form a hollow shell structure with a single side open, the second receiving groove is arranged on the side of the first wall surface away from the pole group, and the first wall surface is also provided with a second plug-in through hole arranged in the second receiving groove;

[0036] The second insulating layer is injection molded on the first wall and includes a second upper insulating portion, a second lower insulating portion and a second plug-in portion. The second upper insulating portion is arranged on the side of the first wall facing away from the pole group and is located in the second accommodating groove. The second lower insulating portion is arranged on the side of the first wall facing the pole group. The second plug-in portion is inserted in the second plug-in through hole and is used to connect the second upper insulating portion and the second lower insulating portion. The second through-structure penetrates the second upper insulating portion, the second plug-in portion and the second lower insulating portion.

[0037] Optionally, in step S6, the following steps are also included:

[0038] S61, a first mounting groove is further formed on a side of the first upper insulating portion facing away from the cover body, a second mounting groove is further formed on a side of the second upper insulating portion facing away from the shell body, the battery further comprises a connecting piece, and the connecting piece is installed in the first mounting groove and the second mounting groove;

[0039] S62, bending the tabs extending out of the first penetrating structure and the second penetrating structure, and welding the bent tabs to the connecting sheet;

[0040] S63: The battery further includes a sealing ring, and the sealing ring is installed in the first receiving groove and the second receiving groove;

[0041] S64, placing the composite pole into the first receiving groove and the second receiving groove;

[0042] S65, welding the composite pole and the composite cover plate, and welding the composite pole and the composite shell.

[0043] On the other hand, a battery is provided, wherein the battery is assembled using any of the battery assembly methods described above.

[0044] Beneficial effects of the present invention:

[0045] The present invention provides a battery assembly method, which first welds a composite cover plate to a composite shell, then welds a composite pole to the composite shell and the composite cover plate, and finally connects a pole ear to the composite pole to achieve current conduction, thereby avoiding the influence of other welding processes on the connection quality between the pole ear and the composite pole that have achieved current conduction, and enables the pole ear to achieve current conduction with the composite pole located outside the composite shell through a first penetration structure and a second penetration structure, thereby eliminating the space occupied by the pole ear and the composite pole and the composite pole extending into the composite shell, 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 pole group and improving the energy density on the other hand. In addition, by adopting a composite shell with a single-side opening and a single composite cover plate structure, the side of the pole ear extending from the pole group through the second penetration structure of the composite shell has less welding work, thereby reducing the influence of the high temperature generated by the welding operation on the microstructure of the pole ear on this side, reducing the resistance of the pole ear on this side, and improving the discharge performance and cycle life of the overall battery.

[0046] 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

[0047] Figure 1 is a flow chart of a battery assembly method provided by the present invention;

[0048] Figure 2 is a structural exploded view of the battery provided by the present invention;

[0049] Figure 3 It is a partial structural cross-sectional view of the first wall surface of the composite shell of the battery provided by the present invention;

[0050] Figure 4 It is a partial structural cross-sectional view of the composite cover plate in the battery provided by the present invention;

[0051] Figure 5 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;

[0052] Figure 6It is a schematic diagram of the distribution of the hot melting points of the first insulating layer and the insulating film in the battery provided by the present invention;

[0053] Figure 7 yes Figure 6 A magnified view of the structure of part A;

[0054] Figure 8 It is a schematic diagram of the distribution of pre-welding points of the composite cover plate and the composite shell in the battery provided by the present invention;

[0055] Fig. 9 It is a schematic structural diagram of the outer shell body of the battery provided by the present invention;

[0056] Fig.10 is a schematic structural diagram of the second insulating layer in the battery provided by the present invention;

[0057] Fig.11 It is a schematic diagram of the structure of the cover plate body in the battery provided by the present invention;

[0058] Fig.12 It is a schematic structural diagram of the first insulating layer in the battery provided by the present invention.

[0059] In the figure:

[0060] 100, first pre-welding point;

[0061] 1. Composite housing; 11. Housing body; 111. First wall surface; 112. Second wall surface; 113. Second receiving groove; 114. Second plug-in through hole; 12. Second insulating layer; 121. Second upper insulating portion; 122. Second lower insulating portion; 123. Second plug-in portion; 124. Second penetration structure; 125. Second shaping structure; 126. Second mounting groove;

[0062] 2. pole group; 21. pole ear; 22. first surface; 23. second surface; 24. side surface;

[0063] 3. Composite cover plate; 31. Cover plate body; 311. First receiving groove; 312. First plug-in through hole; 32. First insulating layer; 321. First upper insulating portion; 322. First lower insulating portion; 323. First plug-in portion; 324. First penetration structure; 325. First shaping structure; 326. First mounting groove;

[0064] 4. Composite pole; 41. Pole body; 42. Welding ring; 43. Third insulating layer;

[0065] 5. Insulating film; 51. Positioning hole; 52. Thermal melting point;

[0066] 6. Protective side panels;

[0067] 7. Connecting piece; 71. Connecting boss;

[0068] 8. Sealing ring. DETAILED DESCRIPTION

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] In order to avoid the connection between the pole and the lug in advance, which may cause other subsequent processes to affect the connection quality between the pole and the lug, reduce the impact of high temperature generated by a large number of welding operations on the microstructure of the lug, and reduce additional space occupation, improve space utilization and energy density, this embodiment provides a battery assembly method, and the battery assembled by the battery assembly method includes a composite shell 1, a pole group 2, a composite cover plate 3 and a composite pole 4.

[0074] like Figures 1 to 12As shown, the battery assembly method includes the following steps:

[0075] S1, the pole group 2 includes a first surface 22 and a second surface 23 provided with a pole ear 21, and a plurality of side surfaces 24 perpendicular to the first surface 22 and the second surface 23, and an insulating film 5 is coated on the outer side of the plurality of side surfaces 24;

[0076] S2. The composite cover plate 3 is provided with a first penetration structure 324 for the pole ear 21 to extend out. The composite cover plate 3 is installed on the first surface 22 of the pole group 2, and the pole ear 21 on the first surface 22 passes through the first penetration structure 324.

[0077] S3, a first insulating layer 32 for isolating the composite cover plate 3 and the electrode lug 21 is injection molded on the composite cover plate 3, and the overlapping area between the insulating film 5 coated on the outside of the electrode group 2 and the first insulating layer 32 on the composite cover plate 3 loaded on the first surface 22 is hot-melted;

[0078] S4, the composite housing 1 is a single-side open structure with a cavity, a second through-structure 124 for the pole ear 21 to extend is provided on the wall surface opposite to the open side, and a second insulating layer 12 for isolating the composite housing 1 from the pole ear 21 is injection-molded on the wall surface, the pole group 2 with the composite cover plate 3 on the first surface 22 is installed into the cavity of the composite housing 1, and the pole ear 21 on the second surface 23 is passed through the second through-structure 124, and the composite cover plate 3 closes the opening of the composite housing 1;

[0079] S5, welding the composite cover plate 3 used for closing the open opening of the composite shell 1 to the composite shell 1;

[0080] S6. A first receiving groove 311 is provided on the side of the composite cover plate 3 facing away from the pole group 2, and a second receiving groove 113 is provided on the side of the composite shell 1 facing away from the pole group 2. The composite pole 4 is installed into the first receiving groove 311 and the second receiving groove 113, and the composite pole 4 is welded to the composite cover plate 3 and the composite pole 4 is welded to the composite shell 1;

[0081] S7, achieving current conduction between the composite pole 4 and the pole ear 21.

[0082] The battery assembly method first welds the composite cover plate 3 to the composite shell 1, then welds the composite pole 4 to the composite shell 1 and the composite cover plate 3, and finally connects the pole ear 21 to the composite pole 4 to achieve current conduction, thereby avoiding the influence of other welding processes on the connection quality between the pole ear 21 and the composite pole 4 that have achieved current conduction, and enables the pole ear 21 to achieve current conduction with the composite pole 4 located outside the composite shell 1 through the first penetration structure 324 and the second penetration structure 124, eliminating the need to connect the pole ear 21 to the composite pole 4 and extend the composite pole 4 into the composite shell 1. The space occupied by the interior is reduced, thereby on the one hand reducing the occupation of the internal space and improving the utilization of the space, and on the other hand providing space for increasing the pole group 2 and improving the energy density. In addition, by adopting a single-sided open composite shell 1 in combination with a single composite cover plate 3, the pole ear 21 side of the pole group 2 extending through the second through structure 124 of the composite shell 1 has less welding work, thereby reducing the influence of the high temperature generated by the welding operation on the microstructure of the pole ear 21 on this side, reducing the resistance of the pole ear 21 on this side, and improving the discharge performance and cycle life of the overall battery.

[0083] Alternatively, if Figure 2 , Figure 5 As shown, in step S1, the following steps are also included:

[0084] S11, the battery further includes at least one protective side plate 6, and at least one protective side plate 6 is pre-heat-fused to a set position of the insulating film 5;

[0085] S12, covering the multiple side surfaces 24 of the electrode group 2 with the insulating film 5, and making at least one protective side plate 6 cover one of the side surfaces 24 of the electrode group 2.

[0086] By hot-melting the protective side plate 6 on the insulating film 5 before coating the insulating film 5, the protective side plate 6 can cover one of the side surfaces 24 of the electrode group 2 when the insulating film 5 is coated on the electrode group 2, so that when the electrode group 2 is put into the shell, the side surface 24 of the electrode group 2 is protected by the protective side plate 6 to avoid scratches when the electrode group 2 is put into the shell.

[0087] The number of the protective side plates 6 can be freely set according to the protection requirements. In the present embodiment, four protective side plates 6 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.

[0088] Alternatively, if Figure 2 , Figure 5 As shown, in step S11, the following steps are also included:

[0089] S111, opening a positioning hole 51 at a set position of the insulating film 5;

[0090] S112, a positioning structure cooperating with the positioning hole 51 is provided on the protective side plate 6, the protective side plate 6 is arranged at a set position of the insulating film 5, and the positioning structure is aligned with the positioning hole 51;

[0091] S113, hot-melt the assembled protective side plate 6 and the insulating film 5.

[0092] By opening a positioning hole 51 at a set position of the insulating film 5 and providing a positioning structure that cooperates with the positioning hole 51 on the protective side plate 6, the accuracy of the hot-melt position of the protective side plate 6 can be ensured, thereby avoiding the inaccurate position of the protective side plate 6 after hot-melting, which makes it impossible to provide effective protection when the insulating film 5 covers the pole group 2.

[0093] Alternatively, if Figure 2 , Figure 6 , Figure 7 As shown, in step S2, the following steps are also included:

[0094] S21, pre-install the composite cover plate 3 on the side of the first surface 22 away from the electrode group 2, and make the electrode ear 21 pass through the first penetration structure 324;

[0095] S22, measuring the distance L1 between the closest points of the composite cover plate 3 and the insulating film 5, and determining whether L1 satisfies 0.5 mm ≤ L1 ≤ 3 mm, if yes, executing step S3, if not, executing step S23;

[0096] S23, after removing the pre-installed composite cover plate 3, the insulating film 5 is trimmed, and after the trimming is completed, step S21 is executed.

[0097] By pre-installing the composite cover plate 3 and determining that the distance dimension L1 between the composite cover plate 3 and the insulating film 5 satisfies the range of 0.5mm≤L1≤3mm, on the one hand, it is possible to avoid the distance dimension L1 between the composite cover plate 3 and the insulating film 5 being too small, which will affect the welding of the composite cover plate 3 and the composite shell 1 and easily cause problems such as welding explosion points. On the other hand, it is possible to avoid the distance dimension L1 between the composite cover plate 3 and the insulating film 5 being too large, which will increase the height dimension of the first lower insulating part 322 and increase the manufacturing cost.

[0098] In this embodiment, the distance dimension L1 between the cut insulating film 5 and the composite cover plate 3 after assembly can 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.

[0099] Alternatively, if Figure 2 , Figure 6 , Figure 7As shown, a plurality of spaced-apart thermal melting points 52 are provided in the overlapping region between the insulating film 5 and the first insulating layer 32, and the distance between the boundary of each thermal melting point 52 away from the pole group 2 and the boundary of the overlapping region away from the pole group 2 is L2, and satisfies 0.5mm≤L2≤3mm.

[0100] By setting a plurality of spaced hot melting points 52, hot melting between the insulating film 5 and the first insulating layer 32 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 52 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 52 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 52 and the boundary of the overlapping area away from the pole group 2 maintain a suitable distance, on the one hand, avoiding the insufficient area that can be operated 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 52 away from the pole group 2 due to too large a distance.

[0101] Among them, the distance dimension L2 between the boundary of each thermal melting point 52 away from the electrode group 2 and the boundary of the overlapping area away from the electrode 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.

[0102] Alternatively, if Figure 2 , Figure 6 , Figure 7 As shown, the distance between the boundary of each thermal melting point 52 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.

[0103] By setting a plurality of spaced hot melting points 52, hot melting between the insulating film 5 and the first insulating layer 32 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 52 away from the composite cover plate 3 and the boundary of the overlapping area toward the pole group 2 as L3, and limiting the distance dimension L3 between the boundary of each hot melting point 52 toward the pole group 2 and the boundary of the overlapping area toward the pole group 2 to satisfy 0.5mm≤L3≤3mm, it is ensured that the hot melting point 52 and the boundary of the overlapping area toward the pole group 2 maintain a suitable distance, on the one hand, avoiding too small a distance, resulting in insufficient operable area during hot melting, and on the other hand, avoiding too large a distance, resulting in loose connection of the area on the side of the hot melting point 52 away from the composite cover plate 3.

[0104] Among them, the distance dimension L3 between the boundary of each thermal melting point 52 toward the pole group 2 and the boundary of the overlapping area away from the composite cover plate 3 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.

[0105] Alternatively, if Figure 2 , Figure 8 As shown, in step S5, the following steps are also included:

[0106] S51, pre-welding and positioning the composite cover plate 3 and the composite shell 1 at the open sides of the composite shell 1 through a plurality of first pre-welding points 100 arranged at intervals;

[0107] S52, fully welding the composite cover plate 3 and the composite shell 1 at the open parts on both sides of the composite shell 1.

[0108] By pre-welding the composite cover plate 3 and the composite shell 1 using a plurality of first pre-welding points 100 arranged at intervals, it is ensured that the relative position between the composite cover plate 3 and the composite shell 1 is positioned before full welding. Even if the initial positioning is incorrect, it is convenient to separate and reposition the two, thereby achieving recycling and reducing the scrap rate of the product.

[0109] In this embodiment, since the composite cover plate 3 includes a large end surface with a larger area and a small end surface with a smaller area, the areas of the overlapping regions formed by different end surfaces and the composite housing 1 are also different, wherein at least three first pre-welding positions 100 are set on the surface with a larger area, preferably five, and at least one first pre-welding position 100 is set on the surface with a smaller area, preferably three, wherein the shape of the first pre-welding position 100 can be freely set according to demand, such as circular, elliptical or polygonal. Wherein, when there are multiple first pre-welding positions 100, it is necessary to ensure that the multiple first pre-welding positions 100 arranged at intervals are evenly distributed.

[0110] Alternatively, if Figure 2 , Figure 4 , Fig.11 , Fig.12 As shown, the composite cover plate 3 includes a cover plate body 31 and a first insulating layer 32, a first receiving groove 311 is opened on the cover plate body 31, and a first plug-in through hole 312 is also opened on the cover plate body 31 and is arranged in the first receiving groove 311. The first insulating layer 32 is injection molded on the cover plate body 31, and includes a first upper insulating portion 321, a first lower insulating portion 322 and a first plug-in portion 323. The first upper insulating portion 321 is arranged on the side of the cover plate body 31 away from the pole group 2 and is located in the first receiving groove 311. The first lower insulating portion 322 is arranged on the side of the cover plate body 31 facing the pole group 2 and is located between the cover plate body 31 and the pole group 2. The first plug-in portion 323 is inserted in the first plug-in through hole 312 and is used to connect the first upper insulating portion 321 and the first lower insulating portion 322. The first penetration structure 324 penetrates the first upper insulating portion 321, the first plug-in portion 323 and the first lower insulating portion 322.

[0111] By setting a first insulating layer 32 composed of a first upper insulating part 321, a first lower insulating part 322 and a first plug-in part 323, and making the first upper insulating part 321 arranged on the side of the cover body 31 away from the pole group 2, and making the first lower insulating part 322 arranged on the side of the cover body 31 facing the pole group 2, making the first plug-in part 323 inserted in the first plug-in through hole 312, and making the first penetrating structure 324 penetrate the first upper insulating part 321, the first plug-in part 323 and the first lower insulating part 322, the first insulating layer 32 is used to achieve insulation protection for both sides of the cover body 31 and the inside of the first plug-in through hole 312, and isolate the pole ear 21 from 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.

[0112] 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, wherein the composite cover plate 3 includes a cover plate body 31 and a first insulating layer 32 composed of a first upper insulating portion 321, a first lower insulating portion 322 and a first plug-in portion 323. Therefore, the distance dimension L1 between the closest point between the composite cover plate 3 and the insulating film 5 is essentially the distance between the cover plate body 31 and the insulating film 5. The distance between the boundary on one side of the pole group 2, the distance dimension L2 between the boundary on the side of the hot melting point 52 away from the pole group 2 and the boundary on the side of the overlapping area away from the pole group 2, is essentially the distance between the boundary on the side of the hot melting point 52 away from the pole group 2 and the boundary on the side of the overlapping area of ​​the first lower insulating portion 322 away from the pole group 2, the distance dimension L3 between the boundary on the side of the hot melting point 52 toward the pole group 2 and the boundary on the side of the overlapping area toward the pole group, is essentially the distance between the boundary on the side of the hot melting point 52 toward the pole group 2 and the boundary on the side of the overlapping area of ​​the first lower insulating portion 322 toward the pole group 2.

[0113] Table 1

[0114]

[0115] In Example 1, the distance L1 between the composite cover plate 3 and the insulating film 5 is set to 0.5 mm, the distance L2 between the boundary of the hot melting point 52 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 L3 between the boundary of the hot melting point 52 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, 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 5 is not damaged and does not fall off.

[0116] In Example 2, the distance L1 between the composite cover plate 3 and the insulating film 5 is set to 1 mm, the distance L2 between the boundary of the hot melting point 52 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 52 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 5 is not damaged and does not fall off.

[0117] In Example 3, the distance L1 between the composite cover plate 3 and the insulating film 5 is set to 1.5 mm, the distance L2 between the boundary of the hot melting point 52 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 52 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 5 is not damaged and does not fall off.

[0118] In Example 4, the distance L1 between the composite cover plate 3 and the insulating film 5 is set to 2 mm, the distance L2 between the boundary of the hot melting point 52 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 52 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 there is no explosion point in the peripheral weld of the shell cover. After disassembling the battery, the insulating film 5 is not damaged and does not fall off.

[0119] In Example 5, the distance L1 between the composite cover plate 3 and the insulating film 5 is set to 2.5 mm, the distance L2 between the boundary of the hot melting point 52 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 52 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 5 is not damaged and has not fallen off.

[0120] In Example 6, the distance L1 between the composite cover plate 3 and the insulating film 5 is set to 3 mm, the distance L2 between the boundary of the hot melting point 52 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 52 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 5 is not damaged and does not fall off.

[0121] It can be seen from Examples 1 to 6 that when the distance dimension L1 between the composite cover plate 3 and the insulating film 5 satisfies the range of 0.5mm≤L1≤3mm, the distance dimension L2 between the boundary of the hot melting point 52 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 52 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 5 is not damaged or falls off, and has high product quality.

[0122] In comparative example 1, the distance dimension L1 between the composite cover plate 3 and the insulating film 5 is set to 0.1 mm, the distance dimension L2 between the boundary of the hot melting point 52 away from the pole group 2 and the boundary of the overlapping area away from the pole group 2 is set to 1 mm, and the distance dimension L3 between the boundary of the hot melting point 52 toward the pole group 2 and the boundary of the overlapping area toward the pole group 2 is set to 1 mm. At this time, the assembled battery is completed according to the above data. It is verified that a burst point occurs during the welding of the periphery of the shell cover, and the insulating film 5 melts. It can be seen from comparative example 1 that when the distance dimension L1 between the composite cover plate 3 and the insulating film 5 is less than the minimum value of 0.5 mm ≤ L1 ≤ 3 mm, at this time, since the insulating film 5 is close to the cover plate body 31, a burst point occurs when welding the periphery of the shell cover, and since the insulating film 5 is too close to the welding position, the high temperature generated by the welding causes the insulating film 5 to melt, resulting in poor insulation protection performance of the assembled battery.

[0123] In comparative example 2, the distance dimension L1 between the composite cover plate 3 and the insulating film 5 is set to 1mm, the distance dimension L2 between the boundary of the hot melting point 52 away from the pole group 2 and the boundary of the overlapping area away from the pole group 2 is set to 0.1mm, and the distance dimension L3 between the boundary of the hot melting point 52 toward the pole group 2 and the boundary of the overlapping area toward the pole group 2 is set to 1mm. At this time, the assembled battery is completed according to the above data, and it is verified that the insulating film 5 has fallen off. It can be seen from comparative example 2 that when the dimension L2 of the distance between the boundary of the hot melting point 52 away from the pole group 2 and the boundary of the overlapping area away from the pole group 2 is less than the minimum value of 0.5mm≤L2≤3mm, the hot melting point 52 is close to the upper edge of the overlapping area of ​​the first lower insulating part 322, resulting in part of the hot melting point exceeding the upper edge of the insulating film 5, resulting in insufficient hot melting area between the insulating film 5 and the first lower insulating part 322, thereby causing the problem of the insulating film 5 falling off, resulting in poor insulation protection performance of the assembled battery.

[0124] In comparative example 3, the distance L1 between the composite cover plate 3 and the insulating film 5 is set to 1 mm, the distance L2 between the boundary of the hot melting point 52 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 52 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 is assembled according to the above data, and it is verified that there is a melting phenomenon between the insulating film 5 and the first lower insulating portion 322, resulting in a short circuit. It can be seen from Comparative Example 3 that when the distance dimension L3 between the boundary of the hot melting point 52 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 52 is close to the lower edge of the overlapping area of ​​the first lower insulating portion 322, part of the hot melting point 52 exceeds the lower edge of the first lower insulating portion 322, resulting in melting through between the insulating film 5 and the first lower insulating portion 322, thereby causing a short circuit problem, resulting in poor insulation protection performance of the assembled battery.

[0125] In comparative example 4, the distance dimension L1 between the composite cover plate 3 and the insulating film 5 is set to 4mm, the distance dimension L2 between the boundary of the hot melting point 52 away from the pole group 2 and the boundary of the overlapping area away from the pole group 2 is set to 1mm, and the distance dimension L3 between the boundary of the hot melting point 52 toward the pole group 2 and the boundary of the overlapping area toward the pole group 2 is set to 1mm. At this time, the assembled battery is completed according to the above data. It is verified that the first lower insulating part 322 occupies a large internal space, resulting in the compression of the pole group 2, which leads to a low energy density of the assembled battery. It can be seen from comparative example 4 that when the distance dimension L1 between the composite cover plate 3 and the insulating film 5 is greater than the maximum value of 0.5mm≤L1≤3mm, at this time, because the insulating film 5 is far away from the cover plate body 31, the first lower insulating part 322 occupies a large internal space, so in order to complete the assembly, it is necessary to reduce the volume of the pole 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.

[0126] In comparative example 5, the distance L1 between the composite cover plate 3 and the insulating film 5 is set to 1 mm, the distance L2 between the boundary of the hot melting point 52 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 L3 between the boundary of the hot melting point 52 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 5 is located in the area between the hot melting point 52 and the upper edge of the overlapping area of ​​the first lower insulating portion 322, and is not tightly connected to the first lower insulating portion 322, resulting in flanging of the insulating film 5. It can be seen from Comparative Example 5 that when the distance dimension L2 between the boundary of the hot melting point 52 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 52 is far away from the upper edge of the overlapping area of ​​the first lower insulating part 322, the insulating film 5 is located in the area between the hot melting point 52 and the upper edge of the overlapping area of ​​the first lower insulating part 322, and is not tightly connected to the first lower insulating part 322, resulting in flanging of the insulating film 5, which does not meet the use requirements.

[0127] In comparative example 6, the distance dimension L1 between the composite cover plate 3 and the insulating film 5 is set to 1 mm, the distance dimension L2 between the boundary of the hot melting point 52 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 52 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 5 is located in the area between the hot melting point 52 and the lower edge of the overlapping area of ​​the first lower insulating portion 322, and is not tightly connected to the first lower insulating portion 322, and there is a gap between the insulating film 5 and the electrode group 2. It can be seen from Comparative Example 6 that when the distance dimension L3 between the boundary of the hot melting point 52 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 52 is far away from the lower edge of the overlapping area of ​​the first lower insulating portion 322, the insulating film 5 is located in the area between the hot melting point 52 and the lower edge of the overlapping area of ​​the first lower insulating portion 322, and is not tightly connected to the first lower insulating portion 322, thereby weakening the wrapping and tightening force of the insulating film 5 on the pole group 2, resulting in easy generation of gaps between the insulating film 5 and the pole group 2, which does not meet the use requirements.

[0128] Alternatively, if Figure 4As shown, a first shaping structure 325 corresponding to the first through structure 324 is provided on the side of the first lower insulating portion 322 facing the pole group 2. The first shaping structure 325 is a trumpet-shaped structure whose opening gradually decreases in the direction away from the pole group 2. Thus, in step S2, 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.

[0129] Alternatively, if Figure 2 , Figure 4 , Fig. 9 , Fig.10 As shown, the composite shell 1 includes a shell body 11 and a second insulating layer 12, the shell body 11 includes a first wall 111 and a plurality of second walls 112 perpendicular to the first wall 111, the plurality of second walls 112 are arranged around the first wall 111 to form a hollow shell structure with a single side open, the second receiving groove 113 is opened on the side of the first wall 111 away from the pole group 2, the first wall 111 is further provided with a second plug-in through hole 114 arranged in the second receiving groove 113, the second insulating layer 12 is injection molded on the first wall 111, and It includes a second upper insulating part 121, a second lower insulating part 122 and a second plug-in part 123. The second upper insulating part 121 is arranged on the side of the first wall 111 away from the pole group 2 and is located in the second accommodating groove 113. The second lower insulating part 122 is arranged on the side of the first wall 111 facing the pole group 2. The second plug-in part 123 is inserted in the second plug-in through hole 114 and is used to connect the second upper insulating part 121 and the second lower insulating part 122. The second through structure 124 penetrates the second upper insulating part 121, the second plug-in part 123 and the second lower insulating part 122.

[0130] By setting a second insulating layer 12 composed of a second upper insulating part 121, a second lower insulating part 122 and a second plug-in part 123, and making the second upper insulating part 121 be arranged on the side of the first wall 111 of the shell body 11 away from the pole group 2, and making the second lower insulating part 122 be arranged on the side of the first wall 111 of the shell body 11 facing the pole group 2, making the second plug-in part 123 inserted into the second plug-in through hole 114, and making the second penetrating structure 124 penetrate the second upper insulating part 121, the second plug-in part 123 and the second lower insulating part 122, the second insulating layer 12 is used to achieve insulation protection for both sides of the first wall 111 of the shell body 11 and the inside of the second plug-in through hole 114, and the pole ear 21 and the first wall 111 of the shell body 11 are isolated, so as to avoid direct contact between the pole ear 21 and the first wall 111 of the shell body 11 when passing through the first wall 111 of the shell body 11, resulting in a short circuit, thereby ensuring safety and protection.

[0131] Alternatively, if Figure 3As shown, a second shaping structure 125 corresponding to the second lower through structure 325 is provided on the side of the second lower insulating portion 122 facing the pole group 2, and the second shaping structure 125 is a trumpet-shaped structure whose opening gradually decreases in the direction away from the pole group 2, so that in step S4, 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.

[0132] Alternatively, if Figure 3 , Figure 4 , Fig.11 , Fig.12 As shown, in step S6, the following steps are also included:

[0133] S61, a first mounting groove 326 is further defined on the side of the first upper insulating portion 321 away from the cover body 31, a second mounting groove 126 is further defined on the side of the second upper insulating portion 121 away from the shell body 11, and the battery further includes a connecting piece 7, and the connecting piece 7 is installed in the first mounting groove 326 and the second mounting groove 126;

[0134] S62, bending the pole lug 21 extending out of the first through structure 324 and the second through structure 124, and welding the bent pole lug 21 to the connecting sheet 7;

[0135] S63: The battery further includes a sealing ring 8, and the sealing ring 8 is installed in the first receiving groove 311 and the second receiving groove 113;

[0136] S64, placing the composite pole 4 into the first receiving groove 311 and the second receiving groove 113;

[0137] S65, welding the composite pole 4 and the composite cover plate 3 as well as the composite pole 4 and the composite housing 1.

[0138] By providing the connecting piece 7 and welding the pole lug 21 to the connecting piece 7, the position of the pole lug 21 can be fixed in advance by using the connecting piece 7, thereby ensuring the accuracy of the position of the pole lug 21 during subsequent operations and avoiding the pole lug 21 from moving and affecting the conduction effect of the current between the pole lug 21 and the composite pole 4.

[0139] Alternatively, if Figure 3 , Figure 4 As shown, in step S7, the following steps are also included:

[0140] S71, a connecting boss 71 is provided on one side of the connecting piece 7 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 71 through a plurality of second pre-welding points arranged at intervals;

[0141] S72, fully welding the composite pole 4 and the connecting boss 71.

[0142] By providing a connecting boss 71 on the side of the connecting piece 7 facing the composite pole 4, it is convenient to weld the connecting piece 7 to the composite pole 4. The size and shape of the connecting boss 71 can be freely set according to demand, and it is sufficient to ensure that there is a sufficient welding area between the connecting boss 71 and the composite pole 4. In this embodiment, the connecting boss 71 is a truncated cone.

[0143] Alternatively, if Figure 2 , Figure 3 , Figure 4 As shown, in step S65, the following steps are also included:

[0144] S651, the composite pole 4 includes a pole body 41, a welding ring 42 and a third 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 first receiving groove 311 and the second receiving groove 113 through a plurality of third pre-welding points arranged at intervals;

[0145] S652 , fully weld the welding ring 42 in the first receiving groove 311 and the second receiving groove 113 .

[0146] In this embodiment, if Figure 2 As shown, a battery is also 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.

[0147] 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 composite shell, an electrode group, a composite cover plate and a composite electrode column; 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, and an insulating film is coated on the outer sides of the plurality of side surfaces; S2, the composite cover plate is provided with a first penetration structure for the electrode lug to extend out, the composite cover plate is installed on the first surface of the electrode group, and the electrode lug on the first surface passes through the first penetration structure; S3, a first insulating layer for isolating the composite cover plate and the electrode lug is injection-molded on the composite cover plate, and the overlapping area between the insulating film coated on the outer side of the electrode group and the first insulating layer on the composite cover plate installed on the first surface is hot-melted; S4, the composite housing is a single-side open structure with a cavity, a second through-structure for the pole ear to extend out is provided on the wall surface opposite to the open side, and a second insulating layer for isolating the composite housing from the pole ear is injection-molded on the wall surface, the pole assembly with the composite cover plate on the first surface is inserted into the cavity of the composite housing, and the pole ear on the second surface is passed through the second through-structure, and the composite cover plate closes the opening of the composite housing; S5, welding the composite cover plate used for closing the opening of the composite shell to the composite shell; S6, a first receiving groove is formed on the side of the composite cover away from the electrode group, and a second receiving groove is formed on the side of the composite shell away from the electrode group, the composite pole is installed in the first receiving groove and the second receiving groove, and the composite pole is welded to the composite cover and the composite pole is welded to the composite shell; S7, achieving current conduction between the composite pole and the pole lug.

2. The battery assembly method according to claim 1, characterized in that: In step S1, the following steps are also included: S11, 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; S12, 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.

3. The battery assembly method according to claim 2, characterized in that: In step S11, the following steps are also included: S111, opening a positioning hole at a set position of the insulating film; S112, 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; S113, hot-melt the assembled protective side plate and the insulating film.

4. The battery assembly method according to claim 1, characterized in that: In step S2, the following steps are also included: S21, pre-installing the composite cover plate on the side of the first surface away from the electrode group, and passing the electrode lug through the first penetration structure; S22, measuring the distance L1 between the closest points of the composite cover plate and the insulating film, and determining whether L1 satisfies 0.5 mm ≤ L1 ≤ 3 mm, if yes, executing step S3, if no, executing step S23; S23, after removing the pre-installed composite cover plate, cutting the insulating film, after the cutting is completed, executing step S21.

5. The battery assembly method according to claim 1, characterized in that: A plurality of thermal melting points are arranged at intervals in the overlapping region between the insulating film and the first insulating layer, 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: In step S5, the following steps are also included: S51, pre-welding and positioning the composite cover plate and the composite shell at the openings on both sides of the composite shell through a plurality of first pre-welding points arranged at intervals; S52, fully welding the composite cover plate and the composite shell at the open positions on both sides of the composite shell.

7. The battery assembly method according to claim 1, characterized in that: The composite cover plate comprises a cover plate body and the first insulating layer; The first receiving groove is formed on the cover body, and the cover body is also provided with a first plugging through hole disposed in the first receiving groove; The first insulating layer is injection molded on the cover body, and includes a first upper insulating portion, a first lower insulating portion and a first plug-in portion. The first upper insulating portion is arranged on a side of the cover body away from the pole group and is located in the first accommodating groove. The first 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 pole group. The first plug-in portion is inserted in the first plug-in through hole and is used to connect the first upper insulating portion and the first lower insulating portion. The first penetrating structure penetrates the first upper insulating portion, the first plug-in portion and the first lower insulating portion.

8. The battery assembly method according to claim 7, characterized in that: The composite housing comprises a housing body and the second insulating layer; The shell body includes a first wall surface and a plurality of second wall surfaces perpendicular to the first wall surface, the plurality of second wall surfaces are arranged around the first wall surface to form a hollow shell structure with a single side open, the second receiving groove is arranged on the side of the first wall surface away from the pole group, and the first wall surface is also provided with a second plug-in through hole arranged in the second receiving groove; The second insulating layer is injection molded on the first wall and includes a second upper insulating portion, a second lower insulating portion and a second plug-in portion. The second upper insulating portion is arranged on the side of the first wall facing away from the pole group and is located in the second accommodating groove. The second lower insulating portion is arranged on the side of the first wall facing the pole group. The second plug-in portion is inserted in the second plug-in through hole and is used to connect the second upper insulating portion and the second lower insulating portion. The second through-structure penetrates the second upper insulating portion, the second plug-in portion and the second lower insulating portion.

9. The battery assembly method according to claim 8, characterized in that: In step S6, the following steps are also included: S61, a first mounting groove is further formed on a side of the first upper insulating portion facing away from the cover body, a second mounting groove is further formed on a side of the second upper insulating portion facing away from the shell body, the battery further comprises a connecting piece, and the connecting piece is installed in the first mounting groove and the second mounting groove; S62, bending the tabs extending out of the first penetrating structure and the second penetrating structure, and welding the bent tabs to the connecting sheet; S63: The battery further includes a sealing ring, and the sealing ring is installed in the first receiving groove and the second receiving groove; S64, placing the composite pole into the first receiving groove and the second receiving groove; S65, welding the composite pole and the composite cover plate, and welding the composite pole and the composite shell.

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

Images