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, coating a second surface and a plurality of side surfaces of a pole group with an insulating film to form a pole group unit; s2, loading the pole group unit into the composite shell, and enabling the tab to extend out of the penetrating structure; s3, a bottom sealing plate is welded to the opening of the composite shell; s4, welding the composite pole with the composite shell; and S5, realizing current conduction between the composite pole and the tab. Current conduction is finally achieved between the tab and the composite pole, so that on one hand, the influence of other welding procedures on the connection quality of the tab and the composite pole is avoided, on the other hand, the bottom sealing plate is arranged on the side, away from the tab, of the composite shell, the influence of high temperature generated by welding operation on the microstructure of the tab is reduced, and the welding quality is improved. And finally, as the tabs extend out of the composite shell to realize current conduction with the composite pole, the occupation of the internal space of the composite shell is reduced, and the utilization rate of the space 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] Lithium-ion power battery is a new type of high-energy battery based on the movement of lithium ions between the positive electrode and the negative electrode. When charging, lithium ions are deintercalated from the positive electrode and embedded in the negative electrode through the electrolyte; when discharging, the opposite is true, and lithium ions are deintercalated from the negative electrode back to the positive electrode to form a current for the device to use. Because lithium-ion power batteries have the advantages of high energy, high battery voltage, wide operating temperature range, and long storage life, they are widely used in electric vehicles, energy storage systems, military equipment, etc. With continuous development, lithium-ion power batteries have derived many different types, such as blade batteries, square shell batteries or large cylindrical batteries. Among them, square shell batteries are known for their cubic or rectangular shape and solid metal shell, with high sealing, long life and good safety. With its advantages of high grouping efficiency and large single cell capacity, square shell batteries are highly competitive in the market. Square shell batteries include pole groups with pole ears on the same side, poles, cover plates, upper plastics, lower plastics, welding stations, sealing rings, and battery shells.

[0003] The traditional assembly process of square shell 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, 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 extended 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 square shell battery.

[0004] However, the square shell battery assembled by this method needs 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. On the one hand, the pole ear and the pole column that have been welded will be affected by adverse factors such as high temperature and vibration when the cover plate is welded to the battery shell, the welding platform is welded to the cover plate, and the welding platform is welded to 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 one side of the pole ear involves welding of the cover plate and the battery shell, welding platform and the cover plate, welding platform and the pole column, and welding of the pole ear and the pole column, a large number of welding operations are gathered on the pole ear side, resulting in the microstructure of the pole ear material being adversely changed 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, reducing the discharge performance and cycle life of the square shell battery. Finally, since this method also requires that the pole column and the pole ear are connected inside the battery shell, the pole ear and the pole column will occupy a large space inside the battery shell, limiting the volume of the pole group, and the energy density is low. Summary of the invention

[0005] 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.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] 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 bottom sealing plate and a composite electrode column;

[0008] The battery assembly method comprises the following steps:

[0009] The battery assembly method comprises the following steps:

[0010] S1, the electrode group includes a first surface with an electrode ear, a second surface parallel to the first surface, and a plurality of side surfaces perpendicular to the first surface and the second surface, and an insulating film is coated on the outer side of the plurality of side surfaces and the second surface to form an electrode group unit;

[0011] S2, the composite shell is a single-side open structure with a cavity, a through structure for the tab to extend is provided on the wall surface opposite to the open side, and a first insulating layer for isolating the composite shell from the tab is injection-molded on the wall surface, the pole group unit is installed in the cavity of the composite shell, and the tab passes through the through structure;

[0012] S3, placing the bottom sealing plate at the open portion of the composite shell to seal the composite shell, and welding the bottom sealing plate to the composite shell;

[0013] S4, a receiving groove is further provided on the wall surface of the composite housing opposite to the opening, and the composite pole is placed in the receiving groove to weld the composite pole to the composite housing;

[0014] S5. Enable 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 a bottom support plate, and the bottom support plate is pre-heat-fused at a set position of the insulating film;

[0017] S12, covering the insulating film on the plurality of side surfaces and the second surface of the pole group, and making the bottom support plate cover the second surface of the pole group to form the pole group unit.

[0018] Optionally, in step S3, the following steps are also included:

[0019] S31, the bottom sealing plate and the composite shell are pre-welded and positioned at a plurality of first pre-welding points arranged at intervals;

[0020] S32, fully welding the bottom sealing plate and the composite shell.

[0021] Optionally, the composite housing comprises a housing body and the first insulating layer;

[0022] 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 receiving groove is arranged on a side of the first wall surface away from the pole group, and the first wall surface is provided with a plug-in through hole arranged in the receiving groove;

[0023] The first insulating layer is injection molded on the first wall, and includes an upper insulating portion, a lower insulating portion and a plug-in portion. The upper insulating portion is arranged on the side of the first wall facing away from the pole group and is located in the accommodating groove. The lower insulating portion is arranged on the side of the first wall facing the pole group. 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 penetrating structure penetrates the upper insulating portion, the plug-in portion and the lower insulating portion.

[0024] Optionally, in step S4, the following steps are also included:

[0025] S41, a mounting groove is further provided on a side of the upper insulating portion away from the first wall surface, and the battery further comprises a connecting piece, and the connecting piece is installed in the mounting groove;

[0026] S42, bending the portion of the electrode tab extending out of the composite housing, and welding the bent electrode tab to the connecting sheet;

[0027] S43, the battery further includes a sealing ring, and the sealing ring is installed in the receiving groove;

[0028] S44, placing the composite pole into the receiving groove, wherein the sealing ring is sandwiched between the composite pole and the composite housing;

[0029] S45, welding the composite pole and the composite shell.

[0030] Optionally, in step S5, the following steps are also included:

[0031] S51, 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 second pre-welding points arranged at intervals;

[0032] S52, fully welding the composite pole and the connecting boss.

[0033] Optionally, in step S42, the bent pole tab is welded to a side of the connecting piece facing the first wall surface, or the bent pole tab is welded to a side of the connecting piece facing the composite pole.

[0034] Optionally, in step S45, the following steps are also included:

[0035] S451, 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 third pre-welding points arranged at intervals;

[0036] S452, fully welding the welding ring in the receiving groove.

[0037] Optionally, a shaping structure corresponding to the through structure is provided on the side of the lower insulating portion facing the pole group, and the shaping structure is a trumpet-shaped structure whose opening gradually decreases in the direction away from the pole group. In step S2, the shaping structure is used to gather and support the pole ear passing through the through structure.

[0038] On the other hand, a battery is provided, wherein the battery is assembled using any of the battery assembly methods described above.

[0039] Beneficial effects of the present invention:

[0040] The present invention provides a battery assembly method, which first welds a bottom sealing plate to a composite shell, then welds a composite pole to the composite shell, 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 been connected, and on the other hand, since the bottom sealing plate is welded to the open side of the composite shell away from the pole group, the amount of welding work on the pole ear side is reduced, and the influence of the high temperature generated by the welding operation on the microstructure of the pole ear is reduced, thereby improving the discharge performance and cycle life of the battery. In addition, the pole ear extends out of the composite shell through a penetrating structure to achieve current conduction with the composite pole, eliminating the space occupied by the connection between the pole ear and the composite pole and the composite pole extending into the composite shell, thereby saving space and improving space utilization.

[0041] 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

[0042] Figure 1 is a flow chart of a battery assembly method provided by the present invention;

[0043] Figure 2 is a structural exploded view of the battery provided by the present invention;

[0044] Figure 3 is a partial front structural cross-sectional view of a battery provided by the present invention;

[0045] Figure 4 is a partial side structural cross-sectional view of a battery provided by the present invention;

[0046] Figure 5 This is a schematic diagram of the distribution of pre-welding points between the bottom sealing plate and the composite shell of the battery provided by the present invention;

[0047] Figure 6 It is a schematic diagram of the structure of the outer shell body of the battery provided by the present invention;

[0048] Figure 7 It is a schematic structural diagram of the first insulating layer in the battery provided by the present invention.

[0049] In the figure:

[0050] 1. Composite shell; 11. Shell body; 111. First wall; 112. Second wall; 113. Accommodating groove; 114. Insertion through hole; 12. First insulating layer; 121. Upper insulating part; 122. Lower insulating part; 123. Insertion part; 124. Through structure; 125. Mounting groove; 126. Shaping structure;

[0051] 2. pole group; 21. pole ear; 22. first surface; 23. second surface; 24. side surface;

[0052] 3. Bottom sealing plate; 31. First pre-welding point;

[0053] 4. Composite pole; 41. Pole body; 42. Welding ring; 43. Second insulating layer;

[0054] 5. Insulation film;

[0055] 6. Bottom support plate;

[0056] 7. Connecting piece; 71. Connecting boss;

[0057] 8. Sealing ring. DETAILED DESCRIPTION

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] The square shell battery consists of the main components such as the electrode group with the pole ears on the same side, the pole column, the cover plate, the upper plastic, the lower plastic, the welding platform, the sealing ring and the battery shell. When the traditional method is used for assembly, the welding of the pole ear and the pole column needs to be completed first, and then 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 are completed. On the one hand, the pole ear and the pole column that have been welded will be affected by adverse factors such as high temperature and vibration when the cover plate and the battery shell are welded, the welding platform and the cover plate are welded, and the welding of the welding platform and the pole column is welded, thereby reducing the welding quality between the pole column and the pole ear and reducing the product yield. On the other hand, since one side of the pole ear involves welding of the cover plate and the battery shell, welding platform and the cover plate, welding platform and the pole column, and welding of the pole ear and the pole column, a large number of welding operations are gathered on the pole ear side, resulting in the microstructure of the pole ear material being adversely changed 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, reducing the discharge performance and cycle life of the square shell battery. Finally, 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 large space inside the battery shell, limiting the volume of the pole group, and the energy density is low.

[0063] Therefore, in order to avoid the connection between the pole post and the pole lug in advance, which may cause other subsequent processes to affect the connection quality between the pole post and the pole lug, reduce the impact of high temperature generated by a large number of welding operations on the microstructure of the pole 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 bottom sealing plate 3 and a composite pole 4.

[0064] like Figures 1 to 7 As shown, the battery assembly method includes the following steps:

[0065] S1, the pole group 2 includes a first surface 22 with a pole ear 21, a second surface 23 parallel to the first surface 22, 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 and the second surface 23 to form a pole group unit;

[0066] S2, the composite housing 1 is a single-side open structure with a cavity, a through structure 124 for the pole ear 21 to extend is provided on the wall surface opposite to the open side, and a first insulating layer 12 for isolating the composite housing 1 from the pole ear 21 is injection-molded on the wall surface, and the pole group unit is installed in the cavity of the composite housing 1, so that the pole ear 21 passes through the through structure 124;

[0067] S3, placing the bottom sealing plate 3 at the open portion of the composite shell 1, closing the composite shell 1, and welding the bottom sealing plate 3 to the composite shell 1;

[0068] S4. A receiving groove 113 is also provided on the wall of the composite housing 1 opposite to the opening, and the composite pole 4 is placed in the receiving groove 113 so that the composite pole 4 is welded to the composite housing 1;

[0069] S5, achieving current conduction between the composite pole 4 and the pole ear 21.

[0070] The battery assembly method first welds the bottom sealing plate 3 to the composite shell 1, then welds the composite pole 4 to the composite shell 1, and finally connects the pole lug 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 lug 21 and the composite pole 4 that have been connected. On the other hand, since the bottom sealing plate 3 is welded to the open side of the composite shell 1 away from the pole group 2, the amount of welding work on the side of the pole lug 21 is reduced, and the influence of the high temperature generated by the welding work on the microstructure of the pole lug 21 is reduced, thereby improving the discharge performance and cycle life of the battery. In addition, the pole lug 21 extends out of the composite shell 1 and the composite pole 4 through the penetration structure 124 to achieve current conduction, eliminating the space occupied by the pole lug 21 and the composite pole 4 and the composite pole 4 extending into the composite shell 1, thereby saving space and improving space utilization.

[0071] Alternatively, if Figure 2 As shown, in step S1, the following steps are also included:

[0072] S11, the battery further includes a bottom support plate 6, and the bottom support plate 6 is pre-heat-fused at a set position of the insulating film 5;

[0073] S12, covering the insulating film 5 on the multiple side surfaces 24 and the second surface 23 of the electrode group 2, and making the bottom support plate 6 cover the second surface 23 of the electrode group 2 to form an electrode group unit.

[0074] By hot-melting the bottom support plate 6 on the insulating film 5 before coating the insulating film 5, when the insulating film 5 is coated on the electrode group 2, the bottom support plate 6 can cover the second surface 23 of the electrode group 2, so that when the electrode group 2 is placed in the shell, the second surface 23 is protected by the bottom support plate 6 when the bottom sealing plate 3 and the composite shell 1 are welded, wherein the area of ​​the bottom support plate 6 is adapted to the area of ​​the second surface 23.

[0075] Alternatively, if Figure 5 As shown, in step S3, the following steps are also included:

[0076] S31, the bottom sealing plate 3 and the composite shell 1 are pre-welded and positioned at a plurality of first pre-welding points 31 arranged at intervals;

[0077] S32, fully welding the bottom sealing plate 3 and the composite shell 1.

[0078] By pre-welding the bottom sealing plate 3 and the composite shell 1 using a plurality of first pre-welding points 31 arranged at intervals, it is ensured that the relative positions of the bottom sealing plate 3 and the composite shell 1 are 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.

[0079] In this embodiment, since the bottom sealing 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 shell 1 are also different, wherein at least three first pre-welding positions 31 are set on the surface with a larger area, preferably five, and at least one first pre-welding position 31 is set on the surface with a smaller area, preferably three, wherein the shape of the first pre-welding position 31 can be freely set according to demand, such as circular, elliptical or polygonal. Wherein, when there are multiple first pre-welding positions 31, it is necessary to ensure that the multiple first pre-welding positions 31 arranged at intervals are evenly distributed.

[0080] Alternatively, if Figure 2 , Figure 4 , Figure 6 , Figure 7 As shown, the composite housing 1 includes a housing body 11 and a first insulating layer 12. The housing body 11 includes a first wall surface 111 and a plurality of second walls 112 perpendicular to the first wall surface 111. The plurality of second walls 112 are arranged around the first wall surface 111 to form a hollow shell structure with a single side open. The receiving groove 113 is provided on the side of the first wall surface 111 away from the pole group 2. The first wall surface 111 is further provided with a plug-in through hole 114 arranged in the receiving groove 113. The plug-in through hole 114 is arranged in the receiving groove 113. The first insulating layer 12 is provided with a first wall surface 111 and a plurality of second walls 112 perpendicular to the first wall surface 111. The plurality of second walls 112 are arranged around the first wall surface 111 to form a hollow shell structure with a single side open. The receiving groove 113 is provided on the first wall surface 111. The insulating layer 12 is injection molded on the first wall 111, and includes an upper insulating portion 121, a lower insulating portion 122 and an insert portion 123. The upper insulating portion 121 is arranged on the side of the first wall 111 away from the pole group 2 and is located in the accommodating groove 113. The lower insulating portion 122 is arranged on the side of the first wall 111 facing the pole group 2. The insert portion 123 is inserted in the insert through hole 114 and is used to connect the upper insulating portion 121 and the lower insulating portion 122. The through structure 124 penetrates the upper insulating portion 121, the insert portion 123 and the lower insulating portion 122.

[0081] By providing a first insulating layer 12 consisting of an upper insulating portion 121, a lower insulating portion 122 and an inserting portion 123, and making the upper insulating portion 121 disposed on the side of the first wall 111 of the shell body 11 away from the pole group 2, and making the lower insulating portion 122 disposed on the side of the first wall 111 of the shell body 11 facing the pole group 2, making the inserting portion 123 inserted into the inserting through hole 114, and making the penetrating structure 124 penetrate the upper insulating portion 121, the inserting portion 123 and the lower insulating portion 122, the first insulating layer 12 is utilized to achieve insulation protection for both sides of the first wall 111 of the shell body 11 and the inside of the inserting 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.

[0082] In this embodiment, the housing body 11 is an aluminum shell, and the first insulating layer 12 is a plastic part directly molded on the first wall 111 of the housing body 11 by an injection molding process. Compared with the traditional cover assembly, the separate lower insulating part is eliminated, thereby reducing the number of parts and simplifying the assembly process. In addition, in this embodiment, the upper insulating part 121, the plug-in part 123 and the lower insulating part 122 are an integrated structural part formed simultaneously by an injection molding process. In other embodiments, the upper insulating part 121, the plug-in part 123 and the lower insulating part 122 can also be separately injection molded and then plugged into each other, so that the first insulating layer 12 is a split structural part.

[0083] Alternatively, if Figure 2 , Figure 4 , Figure 7 As shown, in step S4, the following steps are also included:

[0084] S41, a mounting groove 125 is further provided on a side of the upper insulating portion 121 away from the first wall surface 111, and the battery further includes a connecting piece 7, and the connecting piece 7 is installed in the mounting groove 125;

[0085] S42, bending the portion of the electrode tab 21 extending out of the composite housing 1, and welding the bent electrode tab 21 to the connecting piece 7;

[0086] S43, the battery further includes a sealing ring 8, and the sealing ring 8 is installed in the receiving groove 113;

[0087] S44, the composite pole 4 is placed in the receiving groove 113, and the sealing ring 8 is sandwiched between the composite pole 4 and the composite housing 1;

[0088] S45, welding the composite pole 4 and the composite shell 1.

[0089] 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.

[0090] Among them, the electrode group 2 includes a positive electrode ear and a negative electrode ear located on the same side, so two connecting pieces 7, two sealing rings 8 and two composite poles 4 are correspondingly provided. When assembling the connecting piece 7, the sealing ring 8 and the composite pole 4, the positive electrode ear and the negative electrode ear can be assembled with the connecting piece 7, the sealing ring 8 and the composite pole 4 at the same time, or the connecting piece 7, the sealing ring 8 and the composite pole 4 on the positive electrode ear side can be assembled first, and after the assembly is completed, the connecting piece 7, the sealing ring 8 and the composite pole 4 on the negative electrode ear side can be assembled. In this embodiment, the simultaneous assembly method is adopted to reduce the time required for assembly and improve the efficiency of assembly.

[0091] Alternatively, if Figure 4 As shown, in step S5, the following steps are also included:

[0092] S51, 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;

[0093] S52, fully welding the composite pole 4 and the connecting boss 71.

[0094] 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.

[0095] In addition, the composite pole 4 is first pre-welded to the connecting boss 71 through a plurality of second pre-welding points arranged at intervals, so as to ensure that the relative position between the composite pole 4 and the connecting boss 71 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.

[0096] Optionally, in step S42, the bent pole tab 21 is welded to the side of the connecting piece 7 facing the first wall 111, or the bent pole tab 21 is welded to the side of the connecting piece 7 facing the composite pole 4. In order to adapt to various working environments, it is convenient to perform welding operations on the bent pole tab 21 and the connecting piece 7. In this embodiment, the bent pole tab 21 is welded to the side of the connecting piece 7 facing the composite pole 4.

[0097] Alternatively, if Figure 2 , Figure 4 As shown, in step S45, the following steps are also included:

[0098] S451, 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 113 through a plurality of third pre-welding points arranged at intervals;

[0099] S452 , fully weld the welding ring 42 into the receiving groove 113 .

[0100] First, the welding ring 42 is pre-welded in the receiving groove 113 through a plurality of third pre-welding points arranged at intervals, so as to ensure that the relative position of the welding ring 42 in the receiving groove 113 is positioned before full welding. Even if the initial positioning is wrong, it is convenient to separate and reposition the two, realize recycling, and reduce the scrap rate of the product. The number, size and shape of the third pre-welding points used to realize the pre-welding of the welding ring 42 can be freely set according to actual needs.

[0101] Alternatively, if Figure 4 As shown, a shaping structure 126 corresponding to the through structure 124 is provided on the side of the lower insulating portion 122 facing the pole group 2. The shaping structure 126 is a trumpet-shaped structure whose opening gradually decreases in the direction away from the pole group 2. In step S2, the shaping structure 126 is used to gather and support the pole ear 21 passing through the through structure 124.

[0102] By providing a shaping structure 126 on the side of the lower insulating portion 122 facing the pole group 2, and making the shaping structure 126 a trumpet-shaped structure whose opening gradually decreases in the direction away from the pole group 2, the multiple converged pole ears 21 on the pole group 2 can be better supported and fixed, the convergence state of the pole ears 21 can be improved, and the problem of short circuit inside the battery due to poor convergence effect of the pole ears 21 can be avoided.

[0103] 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.

[0104] 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 bottom sealing plate and a composite electrode column; The battery assembly method comprises the following steps: S1, the electrode group includes a first surface with an electrode ear, a second surface parallel to the first surface, and a plurality of side surfaces perpendicular to the first surface and the second surface, and an insulating film is coated on the outer side of the plurality of side surfaces and the second surface to form an electrode group unit; S2, the composite shell is a single-side open structure with a cavity, a through structure for the tab to extend is provided on the wall surface opposite to the open side, and a first insulating layer for isolating the composite shell from the tab is injection-molded on the wall surface, the pole group unit is installed in the cavity of the composite shell, and the tab passes through the through structure; S3, placing the bottom sealing plate at the open portion of the composite shell to seal the composite shell, and welding the bottom sealing plate to the composite shell; S4, a receiving groove is further provided on the wall surface of the composite housing opposite to the opening, and the composite pole is placed in the receiving groove to weld the composite pole to the composite housing; S5. 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 S1, the following steps are also included: S11, the battery further includes a bottom support plate, and the bottom support plate is pre-heat-fused at a set position of the insulating film; S12, covering the insulating film on the plurality of side surfaces and the second surface of the pole group, and making the bottom support plate cover the second surface of the pole group to form the pole group unit.

3. The battery assembly method according to claim 1, characterized in that: In step S3, the following steps are also included: S31, the bottom sealing plate and the composite shell are pre-welded and positioned at a plurality of first pre-welding points arranged at intervals; S32, fully welding the bottom sealing plate and the composite shell.

4. The battery assembly method according to claim 1, characterized in that: The composite housing comprises a housing body and the first insulating layer; The shell body includes a first wall surface and a plurality of second wall surfaces perpendicular to the first wall surface, wherein the plurality of second wall surfaces are arranged around the first wall surface to form a hollow shell structure with a single-side opening, and the receiving groove is provided on a side of the first wall surface away from the pole group, and the first wall surface is also provided with a plug-in through hole arranged in the receiving groove; The first insulating layer is injection molded on the first wall, and includes an upper insulating portion, a lower insulating portion and a plug-in portion. The upper insulating portion is arranged on the side of the first wall facing away from the pole group and is located in the accommodating groove. The lower insulating portion is arranged on the side of the first wall facing the pole group. 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 penetrating structure penetrates the upper insulating portion, the plug-in portion and the lower insulating portion.

5. The battery assembly method according to claim 4, characterized in that: In step S4, the following steps are also included: S41, a mounting groove is further provided on a side of the upper insulating portion away from the first wall surface, and the battery further comprises a connecting piece, and the connecting piece is installed in the mounting groove; S42, bending the portion of the electrode tab extending out of the composite housing, and welding the bent electrode tab to the connecting sheet; S43, the battery further includes a sealing ring, and the sealing ring is installed in the receiving groove; S44, placing the composite pole into the receiving groove, wherein the sealing ring is sandwiched between the composite pole and the composite housing; S45, welding the composite pole and the composite shell.

6. The battery assembly method according to claim 5, characterized in that: In the step S5, the following steps are also included: S51, 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 second pre-welding points arranged at intervals; S52, fully welding the composite pole and the connecting boss.

7. The battery assembly method according to claim 5, characterized in that: In step S42, the bent pole tab is welded to the side of the connecting piece facing the first wall surface, or the bent pole tab is welded to the side of the connecting piece facing the composite pole.

8. The battery assembly method according to claim 5, characterized in that: In step S45, the following steps are also included: S451, 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 third pre-welding points arranged at intervals; S452, fully welding the welding ring in the receiving groove.

9. The battery assembly method according to claim 4, characterized in that: A shaping structure corresponding to the through structure is provided on one side of the lower insulating portion facing the pole group. The shaping structure is a trumpet-shaped structure whose opening gradually decreases in the direction away from the pole group. In step S2, the shaping structure is used to gather and support the pole ear passing through the through structure.

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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