Battery assembly method and battery

Abstract

The present invention belongs to the field of battery technology and discloses a battery assembly method and a battery, the method comprising: S1, placing a protective end plate on a first surface of a pole group provided with a pole ear; S2, coating an insulating film on multiple side surfaces and the outer side of the second surface of the pole group, and hot-melting the insulating film and the protective end plate to form a pole group unit; S3, installing the pole group unit into the cavity of a battery shell; S4, placing a composite cover plate on the open portion of the battery shell; S5, welding the composite cover plate to the battery shell; S6, welding the composite pole post to the composite shell; S7, achieving current conduction between the composite pole post and the pole ear. By finally achieving current conduction between the pole ear and the composite pole post, the influence of other welding processes on the connection quality between the pole ear and the composite pole post is avoided, and the pole ear achieves current conduction with the composite pole post by extending out of the battery shell, reducing the space occupied by the internal space of the battery shell, improving the space utilization, increasing the pole group volume, and improving the energy density.

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 batteries are a new type of high-energy battery based on the movement of lithium ions between positive and negative electrodes. During charging, lithium ions are deintercalated from the positive electrode and intercalated into the negative electrode through the electrolyte. During discharge, the reverse occurs, with lithium ions deintercalated from the negative electrode back into the positive electrode, generating an electric current for use in devices. Due to their advantages such as high energy, high battery voltage, wide operating temperature range, and long storage life, lithium-ion power batteries have a wide range of applications, including electric vehicles, energy storage systems, and military equipment. With continuous development, lithium-ion power batteries have evolved into various types, such as blade batteries, prismatic batteries, and large cylindrical batteries. Prismatic batteries are known for their cubic or rectangular shape and sturdy metal casing, offering high sealing, long life, and excellent safety. Their high assembly efficiency and large cell capacity make them highly competitive in the market. Prismatic batteries consist of a group of electrodes with tabs located on the same side, a terminal post, a cover plate, an upper plastic, a lower plastic, a soldering station, a sealing ring, and a battery casing.

[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, 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, the cover plate is welded to the battery shell, and then the upper plastic, sealing ring and welding platform are installed in sequence on the outer side of the cover plate corresponding to the part of the pole column, and the welding of the welding platform and the cover plate is completed, 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, for square-shell batteries assembled using this method, on the one hand, it is necessary to complete the welding of the pole ears and pole posts first, and then complete the welding of the cover plate and battery shell, the welding of the welding platform and the cover plate, and the welding of the welding platform and the pole posts. As a result, the pole ears and pole posts that have been welded will be affected by adverse factors such as high temperature and vibration during the welding of the cover plate and battery shell, the welding of the welding platform and the cover plate, and the welding of the welding platform and the pole posts, thereby reducing the welding quality between the pole posts and the pole ears and reducing the product yield. On the other hand, since this method also requires that the pole posts and the pole ears are connected inside the battery shell, the pole ears and pole posts will occupy a larger space inside the battery shell, limiting the volume of the pole group and resulting in a lower energy density. 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 includes a battery housing, an electrode group, a composite cover plate, a composite electrode column, and a protective end plate;

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

[0009] S1. The electrode group includes a first surface with a tab, a second surface parallel to the first surface, and multiple side surfaces perpendicular to the first and second surfaces. The protective end plate is provided with a first through-structure. The protective end plate is installed on the first surface of the electrode group, and the tab passes through the first through-structure.

[0010] S2, coating the outer side of the electrode group with an insulating film so that the insulating film covers the plurality of side surfaces and the outer side of the second surface, and hot-melting the insulating film and the protective end plate to form an electrode group unit;

[0011] S3, the battery housing is a single-side open structure with a cavity, and the electrode group unit is installed in the cavity of the battery housing;

[0012] S4. The composite cover plate is provided with a second through-structure for the tab to extend therethrough and a first insulating layer for isolating the composite cover plate from the tab. The composite cover plate is placed at the opening of the battery housing, and the tab that has passed through the first through-structure is passed through the second through-structure.

[0013] S5, welding the composite cover plate to the battery housing;

[0014] S6. A receiving groove is further provided on the side of the composite cover plate facing away from the electrode group. The composite electrode is installed in the receiving groove and the composite electrode is welded to the composite cover plate.

[0015] S7. Enabling current conduction between the composite pole and the tab.

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

[0017] S21, 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;

[0018] S22, covering the insulating film on the plurality of side surfaces and the second surface of the electrode group, and making the bottom supporting plate cover the second surface of the electrode group;

[0019] S23, hot-melt the overlapping area between the insulating film and the protective end plate to form the pole group unit.

[0020] Optionally, in step S23, the following steps are further included:

[0021] S231, pre-installing the composite cover plate on the side of the protective end plate away from the electrode group, and passing the electrode tab passing through the first penetrating structure through the second penetrating structure;

[0022] S232, 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 so, proceed to step S233; otherwise, proceed to step S234;

[0023] S233: After removing the pre-installed composite cover plate, execute step S23;

[0024] S234 , after removing the pre-installed composite cover plate, the insulating film is trimmed, and after the trimming is completed, step S231 is executed.

[0025] Optionally, a plurality of thermal melting points are provided in the overlapping region between the insulating film and the protective end plate, and a distance L2 is provided between a boundary of each thermal melting point facing away from the electrode group and a boundary of the overlapping region facing away from the electrode group, and 0.5 mm ≤ L2 ≤ 3 mm is satisfied;

[0026] 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.

[0027] Optionally, in step S5, the following steps are further included:

[0028] S51, pre-welding the composite cover plate and the battery housing at a plurality of first pre-welding points arranged at intervals;

[0029] S52: Fully weld the composite cover plate and the battery housing.

[0030] Optionally, the composite cover plate includes a cover plate body and the first insulating layer;

[0031] The receiving groove is provided on the cover body, and the cover body is further provided with a plug-in through hole provided in the receiving groove;

[0032] The first insulating layer is injection molded on the cover body and includes an upper insulating portion, a lower insulating portion and a plug-in portion. The upper insulating portion is provided on the side of the cover body away from the pole group and is located in the accommodating groove. The lower insulating portion is provided on the side of the cover body facing the pole group and is located between the cover body and the protective end plate. The plug-in portion is inserted in the plug-in through hole and is used to connect the upper insulating portion and the lower insulating portion. The second penetrating structure penetrates the upper insulating portion, the plug-in portion and the lower insulating portion and is connected to the first penetrating structure.

[0033] Optionally, in step S6, the following steps are further included:

[0034] S61: A mounting groove is formed on a side of the upper insulating portion facing away from the cover body, and the battery further comprises a connecting piece, wherein the connecting piece is installed in the mounting groove;

[0035] S62, bending the portion of the electrode tab extending out of the second penetrating structure, and welding the bent electrode tab to the connecting piece;

[0036] S63: The battery further includes a sealing ring, and the sealing ring is installed in the receiving groove;

[0037] S64, placing the composite pole into the receiving groove, with the sealing ring being sandwiched between the composite pole and the composite cover plate;

[0038] S65: Welding the composite pole and the composite cover plate.

[0039] Optionally, in step S7, the following steps are further included:

[0040] S71. A connecting boss is provided on a side of the connecting piece facing the composite pole, and is protruding along the composite pole. The composite pole is pre-welded and positioned on the connecting boss by a plurality of second pre-welding points arranged at intervals.

[0041] S72, fully welding the composite pole and the connecting boss.

[0042] Optionally, in step S65, the following steps are further included:

[0043] S651: The composite pole includes a pole body, a welding ring, and a second insulating layer for achieving an insulated connection between the pole body and the welding ring, wherein the welding ring is pre-welded and positioned in the receiving groove via a plurality of third pre-welding points arranged at intervals.

[0044] S652, fully weld the welding ring in the receiving groove.

[0045] On the other hand, a battery is provided, which is assembled using any of the battery assembly methods described above.

[0046] Beneficial effects of the present invention:

[0047] The present invention provides a battery assembly method, which first welds a composite cover plate to a battery shell, then welds a composite pole to 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 already achieved current conduction, and enables the pole ear to extend out of the battery shell and the composite pole through a first through-structure and a second through-structure to achieve current conduction, eliminating the space occupied by the connection between the pole ear and the composite pole and the extension of the composite pole into the interior of the battery shell, thereby saving space, improving space utilization, providing space for increasing the pole group, and improving energy density, and providing a protective end plate with a first through-structure on the side of the pole group where the pole ear is provided, thereby supporting the pole ear, preventing the pole ear from being skewed, and ensuring the reliability of the structure.

[0048] 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

[0049] Figure 1 is a flow chart of the battery assembly method provided by the present invention;

[0050] Figure 2 This is an exploded view of the structure of the battery provided by the present invention;

[0051] Figure 3 This is a partial front structural cross-sectional view of the battery provided by the present invention;

[0052] Figure 4 is a partial side structural cross-sectional view of the battery provided by the present invention;

[0053] Figure 5 This is a schematic diagram of the distribution of hot melting points of the protective end plate and the insulating film in the battery provided by the present invention;

[0054] Figure 6 yes Figure 5 A magnified view of the structure of part A;

[0055] Figure 7 This is a schematic diagram of the distribution of pre-welding points between the composite cover plate and the battery shell in the battery provided by the present invention;

[0056] Figure 8 This is a schematic diagram of the structure of the cover plate body in the battery provided by the present invention;

[0057] Figure 9 Schematic diagram of the structure of the first insulating layer in the battery provided by the present invention;

[0058] Figure 10 It is a structural schematic diagram of the protective end plate in the battery provided by the present invention.

[0059] In the picture:

[0060] 1. Battery housing; 11. First pre-welding point;

[0061] 2. Pole group; 21. Pole ear; 22. First surface; 23. Second surface; 24. Side surface;

[0062] 3. Composite cover plate; 31. Cover plate body; 311. Accommodation groove; 312. Insertion through hole; 32. First insulation layer; 321. Upper insulation portion; 322. Lower insulation portion; 323. Insertion portion; 324. Mounting groove; 325. Second penetration structure;

[0063] 4. Composite pole; 41. Pole body; 42. Welding ring; 43. Second insulating layer;

[0064] 5. Protective end plate; 51. First penetrating structure; 52. Shaping structure;

[0065] 6. Insulating film; 61. Melting point;

[0066] 7. Bottom support plate;

[0067] 8. Connecting piece; 81. Connecting boss;

[0068] 9. Sealing ring. DETAILED DESCRIPTION

[0069] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0070] In the description of the present invention, unless otherwise expressly specified or limited, the terms "connected," "connected," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific circumstances.

[0071] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0072] In the description of this embodiment, the terms "upper," "lower," "right," and other orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely for ease of description and simplified operation. They do not indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used solely for descriptive purposes and have no special meanings.

[0073] A prismatic battery consists of a pole group with the tabs on the same side, a pole post, a cover, upper and lower plastics, a welding platform, a sealing ring, and a battery casing. Traditional assembly methods require welding the tabs to the pole post first, followed by welding the cover to the battery casing, the welding platform to the cover, and finally the pole post. This results in the already welded tabs and pole post being affected by adverse factors such as high temperature and vibration during welding the cover to the battery casing, the welding platform to the cover, and finally the pole post. This reduces the quality of the welding between the pole post and tab, lowering the product yield. Furthermore, because this method also requires the pole post and tab to be connected inside the battery casing, the tabs and pole post occupy a larger space inside the battery casing, limiting the volume of the pole group and resulting in lower energy density.

[0074] Therefore, in order to avoid the connection between the pole and the tab in advance, which may affect the connection quality between the pole and the tab in other subsequent processes, reduce additional space occupation, and improve space utilization and energy density, this embodiment provides a battery assembly method. The battery assembled by this battery assembly method includes a battery casing 1, a pole group 2, a composite cover plate 3, a composite pole 4 and a protective end plate 5.

[0075] like Figures 1 to 10 As shown, the battery assembly method includes the following steps:

[0076] S1, the electrode group 2 includes a first surface 22 with a pole ear 21, a second surface 23 parallel to the first surface 22, and multiple side surfaces 24 perpendicular to the first surface 22 and the second surface 23. The protective end plate 5 is provided with a first through-structure 51. The protective end plate 5 is installed on the first surface 22 of the electrode group 2, and the pole ear 21 passes through the first through-structure 51.

[0077] S2, coating the outer side of the electrode group 2 with an insulating film 6, so that the insulating film 6 covers the outer sides of the plurality of side surfaces 24 and the second surface 23, and heat-melting the insulating film 6 and the protective end plate 5 to form an electrode group unit;

[0078] S3, the battery housing 1 is a single-side open structure with a cavity, and the electrode group unit is installed in the cavity of the battery housing 1;

[0079] S4. The composite cover plate 3 is provided with a second through-structure 325 for the tab 21 to extend therethrough, and a first insulating layer 32 for isolating the composite cover plate 3 from the tab 21. The composite cover plate 3 is placed at the opening of the battery housing 1, and the tab 21 that has passed through the first through-structure 51 is passed through the second through-structure 325.

[0080] S5, welding the composite cover plate 3 to the battery housing 1;

[0081] S6. A receiving groove 311 is further provided on the side of the composite cover plate 3 facing away from the electrode group 2. The composite pole 4 is installed into the receiving groove 311 and the composite pole 4 is welded to the composite cover plate 3.

[0082] S7 , achieving current conduction between the composite pole 4 and the tab 21 .

[0083] The battery assembly method first welds the composite cover plate 3 to the battery shell 1, then welds the composite pole 4 to 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 already achieved current conduction, and makes the pole ear 21 extend out of the battery shell 1 and the composite pole 4 through the first penetrating structure 51 and the second penetrating structure 325 to achieve current conduction, eliminating the space occupied by the connection between the pole ear 21 and the composite pole 4 and the composite pole 4 extending into the interior of the battery shell 1, thereby saving space, improving space utilization, and providing space for increasing the pole group 2, thereby improving energy density, and providing a protective end plate 5 with a first penetrating structure 51 on the side of the pole group 2 where the pole ear 21 is provided, thereby supporting the pole ear 21, preventing the pole ear 21 from being skewed, and ensuring the reliability of the structure.

[0084] Alternatively, as Figure 2 As shown, in step S2, the following steps are also included:

[0085] S21, the battery further includes a bottom support plate 7, which is pre-heated and melted to a set position of the insulating film 6;

[0086] S22, covering the insulating film 6 on the multiple side surfaces 24 and the second surface 23 of the electrode group 2, and making the bottom supporting plate 7 cover the second surface 23 of the electrode group 2;

[0087] S23 , hot-melt the overlapping area between the insulating film 6 and the protective end plate 5 to form a pole group unit.

[0088] By hot-melting the bottom support plate 7 on the insulating film 6 before coating the insulating film 6, when the insulating film 6 is coated on the electrode group 2, the bottom support plate 7 can cover the second surface 23 of the electrode group 2, so that when the electrode group 2 is placed into the shell, the second surface 23 is protected by the bottom support plate 7 to avoid scratches during the placement of the electrode group 2 into the shell, wherein the area of ​​the bottom support plate 7 is adapted to the area of ​​the second surface 23.

[0089] Alternatively, as Figure 2 、 Figure 4 、 Figure 6 As shown, in step S23, the following steps are also included:

[0090] S231, pre-install the composite cover plate 3 on the side of the protective end plate 5 facing away from the electrode group 2, and pass the electrode lug 21 passing through the first penetrating structure 51 through the second penetrating structure 325;

[0091] S232, measuring the distance L1 between the closest points of the composite cover plate 3 and the insulating film 6, and determining whether L1 satisfies 0.5 mm ≤ L1 ≤ 3 mm. If so, proceed to step S233; otherwise, proceed to step S234;

[0092] S233, after removing the pre-installed composite cover plate 3, heat-melt the overlapping area between the insulating film 6 and the protective end plate 5 to form an electrode group unit;

[0093] S234 , after removing the pre-installed composite cover plate 3 , the insulating film 6 is trimmed. After the trimming is completed, step S231 is executed.

[0094] 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 6 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 6 being too small, which affects the welding of the composite cover plate 3 and the battery casing 1 and easily causes 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 6 being too large, which leads to an increase in the height dimension of the protective end plate 5 and an increase in manufacturing costs.

[0095] In this embodiment, the spacing dimension L1 between the cut insulating film 6 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.

[0096] Alternatively, as Figure 2 、 Figure 4 、 Figure 6 As shown, a plurality of thermal melting points 61 are provided in the overlapping area between the insulating film 6 and the protective end plate 5. The distance between the boundary of each thermal melting point 61 facing away from the pole group 2 and the boundary of the overlapping area facing away from the pole group 2 is L2, and satisfies 0.5mm≤L2≤3mm.

[0097] By adopting the method of setting multiple spaced hot melt points 61, hot melting between the insulating film 6 and the protective end plate 5 is achieved, thereby ensuring that the scope of hot melting is wide enough and the firmness of hot melting is guaranteed. 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 61 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 61 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 61 and the boundary of the overlapping area away from the pole group 2 maintain an appropriate distance. On the one hand, it avoids that the distance is too small, resulting in insufficient area for operation during hot melting, and on the other hand, it avoids that the distance is too large, resulting in loose connection of the area on the side of the hot melting point 61 away from the pole group 2.

[0098] In this embodiment, the protective end plate 5 includes a large end surface with a larger area and a small end surface with a smaller area. Therefore, the overlapping areas formed by different end surfaces and the insulating film 6 also vary in area. At least three spaced-apart thermal melting points 61 are provided on the surface with the larger area, and at least one thermal melting point 61 is provided on the surface with the smaller area. The shape of the thermal melting point 61 can be freely set as required, such as circular, elliptical, or polygonal. When multiple thermal melting points 61 are provided, the multiple spaced-apart thermal melting points 61 must be evenly distributed.

[0099] Among them, the distance dimension L2 between the boundary of each thermal melting point 61 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.

[0100] Alternatively, as Figure 2 、 Figure 4 、 Figure 6 As shown, the distance between the boundary of each thermal melting point 61 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.

[0101] By adopting the method of setting multiple spaced hot melt points 61, hot melting between the insulating film 6 and the protective end plate 5 is achieved, thereby ensuring that the scope of hot melting is wide enough and the firmness of hot melting is ensured. On the other hand, compared with the full hot melting method, the hot melting 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 61 facing the pole group 2 side and the boundary of the overlapping area facing the pole group 2 side as L3, and limiting the distance dimension L3 between the boundary of each hot melting point 61 facing the pole group 2 side and the boundary of the overlapping area facing the pole group 2 side to satisfy 0.5mm≤L3≤3mm, it is ensured that the hot melting point 61 and the boundary of the overlapping area facing the pole group 2 side maintain an appropriate distance, on the one hand, avoiding too small a distance, resulting in insufficient area for operation 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 61 facing the pole group 2 side.

[0102] In this embodiment, the protective end plate 5 includes a large end surface with a larger area and a small end surface with a smaller area. Therefore, the overlapping areas formed by different end surfaces and the insulating film 6 also vary in area. At least three thermal melting points 61 are provided on the surface with the larger area, and at least one thermal melting point 61 is provided on the surface with the smaller area. The shape of the thermal melting point 61 can be freely set as required, such as circular, elliptical, or polygonal. When multiple thermal melting points 61 are provided, the multiple thermal melting points 61, which are spaced apart, must be evenly distributed.

[0103] Among them, the distance dimension L3 between the boundary of each thermal melting point 61 toward the pole group 2 side and the boundary of the overlapping area toward the pole group 2 side can be any value between 0.5mm and 3mm or a range between any two values, such as 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, etc.

[0104] Alternatively, as Figure 2 、 Figure 4 、 Figure 7 As shown, in step S5, the following steps are also included:

[0105] S51, the composite cover plate 3 and the battery housing 1 are pre-welded and positioned at a plurality of first pre-welding points 11 arranged at intervals;

[0106] S52 , fully welding the composite cover plate 3 and the battery housing 1 .

[0107] By pre-welding the composite cover plate 3 and the battery shell 1 using a plurality of first pre-welding points 11 set at intervals, it is ensured that the relative positions between the composite cover plate 3 and the battery shell 1 are positioned before full welding. 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.

[0108] 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 area of ​​the overlapping area formed by different end surfaces and the battery housing 1 is also different. On the surface with a larger area, at least three first pre-welding positions 11 are set, preferably five, and on the surface with a smaller area, at least one first pre-welding position 11 is set, preferably three. The shape of the first pre-welding position 11 can be freely set according to needs, such as circular, elliptical or polygonal. When there are multiple first pre-welding positions 11, it is necessary to ensure that the multiple first pre-welding positions 11 set at intervals are evenly distributed.

[0109] Alternatively, as Figure 2 、 Figure 4 、 Figure 8 、 Figure 9 As shown, the composite cover plate 3 includes a cover plate body 31 and a first insulating layer 32, a receiving groove 311 is opened on the cover plate body 31, and a plug-in through hole 312 is opened on the cover plate body 31 and is arranged in the receiving groove 311. The first insulating layer 32 is injection molded on the cover plate body 31 and includes an upper insulating portion 321, a lower insulating portion 322 and a plug-in portion 323. The upper insulating portion 321 is arranged on the side of the cover plate body 31 away from the pole group 2 and is located in the receiving groove 311. The lower insulating portion 322 is arranged on the side of the cover plate body 31 facing the pole group 2 and is located between the cover plate body 31 and the protective end plate 5. The plug-in portion 323 is inserted in the plug-in through hole 312 and is used to connect the upper insulating portion 321 and the lower insulating portion 322. The second through-hole structure 325 penetrates the upper insulating portion 321, the plug-in portion 323 and the lower insulating portion 322 and is connected to the first through-hole structure 51.

[0110] By injection molding the first insulating layer 32 on the cover body 31, the first insulating layer 32 cooperates with the protective end plate 5 to achieve double insulation protection, thereby improving the safety and protection of the structure. In addition, by providing the first insulating layer 32 consisting of an upper insulating portion 321, a lower insulating portion 322 and a plug-in portion 323, the upper insulating portion 321 is provided on the side of the cover body 31 away from the pole group 2, the lower insulating portion 322 is provided on the side of the cover body 31 facing the pole group 2, and the plug-in portion 323 is inserted into the cover body 31. The plug-in through hole 312 is inserted, and the second penetrating structure 325 penetrates the upper insulating part 321, the plug-in part 323 and the lower insulating part 322 to communicate with the first penetrating structure 51, so that the first insulating layer 32 is used to achieve insulation protection for both sides of the cover body 31 and the inside of the plug-in through hole 312, and isolate the pole ear 21 and the cover body 31 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.

[0111] In this embodiment, the cover body 31 is a plain aluminum plate, and the first insulating layer 32 is a plastic part directly molded onto the cover body 31 via an injection molding process. Compared to traditional cover assemblies, the separate lower insulating component is eliminated, thereby reducing the number of parts and simplifying the assembly process. Furthermore, in this embodiment, the upper insulating portion 321, the plug portion 323, and the lower insulating portion 322 are a one-piece structural component formed simultaneously via the injection molding process. In other embodiments, the upper insulating portion 321, the plug portion 323, and the lower insulating portion 322 can be separately injection molded and then plugged into each other, making the first insulating layer 32 a split structural component.

[0112] In this embodiment, in order to verify the influence of the distance dimension L1, the distance dimension L2 and the distance dimension L3 in the battery assembly method on the quality of the assembled product, as shown in Table 1, six groups of embodiments and six groups of comparative examples are provided for verification, wherein the cover body 31 in the composite cover plate 3 is actually welded to the battery shell 1, so the distance dimension L1 between the nearest point between the composite cover plate 3 and the insulating film 6 is actually the distance between the cover body 31 and the boundary of the insulating film 6 away from the electrode group 2.

[0113] Table 1

[0114]

[0115] In Example 1, the distance L1 between the composite cover plate 3 and the insulating film 6 is set to 0.5 mm, the distance L2 between the boundary of the hot melting point 61 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 61 toward the electrode group 2 and the boundary of the overlapping area toward the electrode group 2 is set to 0.5 mm. At this time, the battery is assembled according to the above data. It is verified that no explosion points appear in the welds around the shell cover. After disassembling the battery, the insulating film 6 is not damaged and has not fallen off.

[0116] In Example 2, the distance L1 between the composite cover plate 3 and the insulating film 6 is set to 1 mm, the distance L2 between the boundary of the hot melting point 61 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 61 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. It is verified that no explosion points appear in the welds around the shell cover. After disassembling the battery, the insulating film 6 is not damaged and has not fallen off.

[0117] In Example 3, the distance L1 between the composite cover plate 3 and the insulating film 6 is set to 1.5 mm, the distance L2 between the boundary of the hot melting point 61 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 61 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. It is verified that no explosion points appear in the welds around the shell cover. After disassembling the battery, the insulating film 6 is not damaged and has not fallen off.

[0118] In Example 4, the distance L1 between the composite cover plate 3 and the insulating film 6 is set to 2 mm, the distance L2 between the boundary of the hot melting point 61 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 61 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 no explosion points appear in the welds around the shell cover. After disassembling the battery, the insulating film 6 is not damaged and has not fallen off.

[0119] In Example 5, the distance L1 between the composite cover plate 3 and the insulating film 6 is set to 2.5 mm, the distance L2 between the boundary of the hot melting point 61 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 61 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. It is verified that no explosion points appear in the welds around the shell cover. After disassembling the battery, the insulating film 6 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 6 is set to 3 mm, the distance L2 between the boundary of the hot melting point 61 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 61 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. It is verified that no explosion points appear in the welds around the shell cover. After disassembling the battery, the insulating film 6 is not damaged and has not fallen 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 6 satisfies the range of 0.5mm≤L1≤3mm, the distance dimension L2 between the boundary of the hot melting point 61 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 61 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 this battery assembly method has no explosion points in the weld around the shell cover, and after disassembling the battery, the insulating film 6 is not damaged or falls off, and has high product quality.

[0122] In Comparative Example 1, the distance L1 between the composite cover plate 3 and the insulating film 6 is set to 0.1 mm, the distance L2 between the boundary of the hot melting point 61 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 61 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 explosion points appear during the welding around the shell cover and the insulating film 6 melts.

[0123] It can be seen from Comparative Example 1 that when the distance dimension L1 between the composite cover plate 3 and the insulating film 6 is less than the minimum value of 0.5mm≤L1≤3mm, the insulating film 6 is close to the cover plate body 31, so an explosion point appears when welding the periphery of the shell cover. Moreover, since the insulating film 6 is too close to the welding position, the high temperature generated by the welding causes the insulating film 6 to melt, resulting in poor insulation protection performance of the assembled battery.

[0124] In Comparative Example 2, the distance L1 between the composite cover plate 3 and the insulating film 6 is set to 1 mm, the distance L2 between the boundary of the hot melting point 61 away from the electrode group 2 and the boundary of the overlapping area away from the electrode group 2 is set to 0.1 mm, and the distance L3 between the boundary of the hot melting point 61 toward the electrode group 2 and the boundary of the overlapping area toward the electrode group 2 is set to 1 mm. At this time, the battery after assembly is completed according to the above data, and it is verified that the insulating film 6 has fallen off.

[0125] It can be seen from Comparative Example 2 that when the distance dimension L2 between the boundary of the hot melting point 61 away from the side of the electrode group 2 and the boundary of the overlapping area away from the side of the electrode group 2 is less than the minimum value of 0.5mm≤L2≤3mm, the hot melting point 61 is close to the upper edge of the overlapping area of ​​the protective end plate 5, resulting in part of the hot melting point 61 exceeding the upper edge of the insulating film 6, resulting in insufficient hot melting area between the insulating film 6 and the protective end plate 5, which causes the insulating film 6 to fall off, resulting in poor insulation protection performance of the assembled battery.

[0126] In comparative example 3, the distance L1 between the composite cover plate 3 and the insulating film 6 is set to 1 mm, the distance L2 between the boundary of the hot melting point 61 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 61 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 after assembly is completed according to the above data, it is verified that melting through occurs between the insulating film 6 and the protective end plate 5, resulting in a short circuit.

[0127] It can be seen from Comparative Example 3 that when the distance dimension L3 between the boundary of the hot melting point 61 toward the electrode group 2 and the boundary of the overlapping area toward the electrode group 2 is less than the minimum value of 0.5mm≤L3≤3mm, the hot melting point 61 is close to the lower edge of the overlapping area of ​​the protective end plate 5, resulting in a portion of the hot melting point 61 exceeding the lower edge of the protective end plate 5, causing melting through between the insulating film 6 and the protective end plate 5, thereby causing a short circuit problem, resulting in poor insulation protection performance of the assembled battery.

[0128] In Comparative Example 4, the distance L1 between the composite cover plate 3 and the insulating film 6 is set to 4 mm, the distance L2 between the boundary of the hot melting point 61 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 61 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 found that the protective end plate 5 occupies a large internal space, resulting in the compression of the volume of the electrode group 2, thereby resulting in a lower energy density of the assembled battery.

[0129] It can be seen from Comparative Example 4 that when the distance dimension L1 between the composite cover plate 3 and the insulating film 6 is greater than the maximum value of 0.5mm≤L1≤3mm, the insulating film 6 is far away from the cover plate body 31, so the protective end plate 5 occupies a large internal space. Therefore, in order to complete the assembly, the volume of the electrode group 2 needs to be reduced, thereby reducing the energy density of the assembled battery, the power supply capacity is poor, and it does not meet the use requirements.

[0130] In comparative example 5, the distance L1 between the composite cover plate 3 and the insulating film 6 is set to 1 mm, the distance L2 between the boundary of the hot melting point 61 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 61 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 found that the insulating film 6 is located in the area between the hot melting point 61 and the upper edge of the overlapping area of ​​the protective end plate 5, and is not tightly connected to the protective end plate 5, resulting in flanging of the insulating film 6.

[0131] It can be seen from Comparative Example 5 that when the distance dimension L2 between the boundary of the hot melting point 61 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, the hot melting point 61 is far away from the upper edge of the overlapping area of ​​the protective end plate 5, resulting in the insulating film 6 being located in the area between the hot melting point 61 and the upper edge of the overlapping area of ​​the protective end plate 5, and is not tightly connected to the protective end plate 5, resulting in the insulating film 6 being flanging, which does not meet the use requirements.

[0132] In comparative example 6, the distance L1 between the composite cover plate 3 and the insulating film 6 is set to 1 mm, the distance L2 between the boundary of the hot melting point 61 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 61 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 found that the insulating film 6 is located in the area between the hot melting point 61 and the lower edge of the overlapping area of ​​the protective end plate 5, and is not tightly connected to the protective end plate 5. There is a gap between the insulating film 6 and the electrode group 2.

[0133] It can be seen from Comparative Example 6 that when the distance dimension L3 between the boundary of the hot melting point 61 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, the hot melting point 61 is far away from the lower edge of the overlapping area of ​​the protective end plate 5, resulting in the insulating film 6 being located in the area between the hot melting point 61 and the lower edge of the overlapping area of ​​the protective end plate 5, and is not tightly connected to the protective end plate 5, thereby weakening the strength of the insulating film 6 to wrap and converge the pole group 2, resulting in easy generation of gaps between the insulating film 6 and the pole group 2, which does not meet the use requirements.

[0134] Alternatively, as Figure 2 、 Figure 8 、 Figure 9 、 Figure 10 As shown, in step S6, the following steps are also included:

[0135] S61. A mounting groove 324 is further provided on the side of the upper insulating portion 321 facing away from the cover body 31. The battery further includes a connecting piece 8. The connecting piece 8 is installed in the mounting groove 324.

[0136] S62, bending the tab 21 extending out of the second penetrating structure 325, and welding the bent tab 21 to the connecting piece 8;

[0137] S63: The battery further includes a sealing ring 9, which is installed in the receiving groove 311;

[0138] S64, the composite pole 4 is installed in the receiving groove 311, and the sealing ring 9 is sandwiched between the composite pole 4 and the composite cover plate 3;

[0139] S65. Weld the composite pole 4 and the composite cover plate 3.

[0140] By providing a connecting piece 8 and welding the pole tab 21 to the connecting piece 8, the position of the pole tab 21 can be fixed in advance by using the connecting piece 8, thereby ensuring the accuracy of the position of the pole tab 21 during subsequent operations, and avoiding the displacement of the pole tab 21, which affects the conduction effect of the current between the pole tab 21 and the composite pole 4.

[0141] The electrode group 2 includes a positive electrode tab and a negative electrode tab located on the same side, and therefore is provided with two connecting pieces 8, two sealing rings 9, and two composite electrode posts 4. When assembling the connecting pieces 8, sealing rings 9, and composite electrode posts 4, the positive and negative electrode tabs can be assembled with the connecting pieces 8, sealing rings 9, and composite electrode posts 4 simultaneously. Alternatively, the connecting pieces 8, sealing rings 9, and composite electrode posts 4 on the positive electrode side can be assembled first, and after assembly is complete, the connecting pieces 8, sealing rings 9, and composite electrode posts 4 on the negative electrode side can be assembled. In this embodiment, a simultaneous assembly method is adopted to reduce the time required for assembly and improve assembly efficiency.

[0142] Alternatively, as Figure 2 、 Figure 4 As shown, in step S7, the following steps are also included:

[0143] S71. A connecting boss 81 is provided on the side of the connecting piece 8 facing the composite pole 4 and protrudes along the composite pole 4. The composite pole 4 is pre-welded and positioned on the connecting boss 81 by a plurality of second pre-welding points arranged at intervals.

[0144] S72 , fully weld the composite pole 4 and the connecting boss 81 .

[0145] The connection boss 81 is provided on the side of the connection piece 8 facing the composite pole 4 to facilitate welding of the connection piece 8 to the composite pole 4. The size and shape of the connection boss 81 can be freely adjusted as needed, as long as there is sufficient welding area between the connection boss 81 and the composite pole 4. In this embodiment, the connection boss 81 is a frustum.

[0146] In addition, the composite pole 4 is first pre-welded to the connecting boss 81 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 81 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.

[0147] Alternatively, as Figure 2 、 Figure 4 As shown, in step S65, the following steps are also included:

[0148] S651, the composite pole 4 includes a pole body 41, a welding ring 42, and a second insulating layer 43 for achieving an insulated connection between the pole body 41 and the welding ring 42, and the welding ring 42 is pre-welded and positioned in the receiving groove 311 through a plurality of spaced third pre-welding points;

[0149] S652 , fully weld the welding ring 42 into the receiving groove 311 .

[0150] The welding ring 42 is pre-welded within the receiving groove 311 at multiple, spaced third pre-welding points. This ensures that the relative position of the welding ring 42 within the receiving groove 311 is properly determined before full welding. Even if the initial positioning is incorrect, the two can be easily separated and re-positioned, enabling recycling and reducing product scrap rates. The number, size, and shape of the third pre-welding points used to pre-weld the welding ring 42 can be freely adjusted according to actual needs.

[0151] Optionally, in step S62, after the connecting piece 8 is installed in the installation groove 324, the bent tab 21 is welded to the side of the connecting piece 8 facing the composite cover plate 3, or the bent tab 21 is welded to the side of the connecting piece 8 facing the composite pole 4. This is to adapt to various working environments and facilitate the welding operation of the bent tab 21 and the connecting piece 8. In this embodiment, the bent tab 21 is welded to the side of the connecting piece 8 facing the composite pole 4.

[0152] Alternatively, as Figure 4 As shown, a shaping structure 52 corresponding to the first penetrating structure 51 is provided on the side of the protective end plate 5 facing the pole group 2. The shaping structure 52 is a trumpet-shaped structure whose opening gradually shrinks in the direction away from the pole group 2. Thus, in step S1, the multiple converged pole ears 21 on the pole group 2 are better supported and fixed, the convergence state of the pole ears 21 is improved, and the problem of short circuit inside the battery due to poor convergence effect of the pole ears 21 is avoided.

[0153] In this embodiment, if Figure 2 As shown, a battery is also provided, which is assembled using the above-mentioned battery assembly method. By applying the above-mentioned battery assembly method, 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.

[0154] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. A person skilled in the art would be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A battery assembly method, characterized in that: The battery assembled by the battery assembly method comprises a battery shell, an electrode group, a composite cover plate, a composite electrode column and a protective end plate; The battery assembly method comprises the following steps: S1. The electrode group includes a first surface with a tab, a second surface parallel to the first surface, and multiple side surfaces perpendicular to the first and second surfaces. The protective end plate is provided with a first through-structure. The protective end plate is installed on the first surface of the electrode group, and the tab passes through the first through-structure. S2, coating the outer side of the electrode group with an insulating film so that the insulating film covers the plurality of side surfaces and the outer side of the second surface, and hot-melting the insulating film and the protective end plate to form an electrode group unit; S3, the battery housing is a single-side open structure with a cavity, and the electrode group unit is installed in the cavity of the battery housing; S4. The composite cover plate is provided with a second through-structure for the tab to extend therethrough and a first insulating layer for isolating the composite cover plate from the tab. The composite cover plate is placed at the opening of the battery housing, and the tab that has passed through the first through-structure is passed through the second through-structure. S5, welding the composite cover plate to the battery housing; S6. A receiving groove is further provided on the side of the composite cover plate facing away from the electrode group. The composite electrode is installed in the receiving groove and the composite electrode is welded to the composite cover plate. S7, achieving current conduction between the composite pole and the tab; In step S2, the following steps are also included: S21, 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; S22, covering the insulating film on the plurality of side surfaces and the second surface of the electrode group, and making the bottom supporting plate cover the second surface of the electrode group; S23, hot-melting the overlapping area between the insulating film and the protective end plate to form the electrode group unit; In step S23, the following steps are also included: S231, pre-installing the composite cover plate on the side of the protective end plate away from the electrode group, and passing the electrode tab passing through the first penetrating structure through the second penetrating structure; S232, 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 so, proceed to step S233; otherwise, proceed to step S234; S233, after removing the pre-installed composite cover plate, heat-seal the overlapping area between the insulating film and the protective end plate to form the electrode group unit; S234 , after removing the pre-installed composite cover plate, the insulating film is trimmed, and after the trimming is completed, step S231 is executed.

2. The battery assembly method according to claim 1, characterized in that: A plurality of thermal melting points are provided in the overlapping region between the insulating film and the protective end plate, and a distance L2 is provided between a boundary of each thermal melting point facing away from the electrode group and a boundary of the overlapping region facing away from the electrode group, and the distance L2 satisfies 0.5 mm ≤ L2 ≤ 3 mm; 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.

3. The battery assembly method according to claim 1, wherein: In step S5, the following steps are also included: S51, pre-welding the composite cover plate and the battery housing at a plurality of first pre-welding points arranged at intervals; S52: Fully weld the composite cover plate and the battery housing.

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

5. The battery assembly method according to claim 4, characterized in that: In step S6, the following steps are also included: S61: A mounting groove is formed on a side of the upper insulating portion facing away from the cover body, and the battery further comprises a connecting piece, wherein the connecting piece is installed in the mounting groove; S62, bending the portion of the electrode tab extending out of the second penetrating structure, and welding the bent electrode tab to the connecting piece; S63: The battery further includes a sealing ring, and the sealing ring is installed in the receiving groove; S64, placing the composite pole into the receiving groove, with the sealing ring being sandwiched between the composite pole and the composite cover plate; S65: Welding the composite pole and the composite cover plate.

6. The battery assembly method according to claim 5, characterized in that: In the step S7, the following steps are also included: S71. A connecting boss is provided on a side of the connecting piece facing the composite pole, and is protruding along the composite pole. The composite pole is pre-welded and positioned on the connecting boss by a plurality of second pre-welding points arranged at intervals. S72, fully welding the composite pole and the connecting boss.

7. The battery assembly method according to claim 5, characterized in that: In step S65, the following steps are also included: S651: The composite pole includes a pole body, a welding ring, and a second insulating layer for achieving an insulated connection between the pole body and the welding ring, wherein the welding ring is pre-welded and positioned in the receiving groove via a plurality of third pre-welding points arranged at intervals. S652, fully weld the welding ring in the receiving groove.

8. A battery, characterized in that The battery is assembled using the battery assembly method according to any one of claims 1 to 7.

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