Battery assembly method and battery

Abstract

The application belongs to the technical field of batteries, and discloses a battery assembling method and a battery. The method comprises the following steps: S1, a second cover plate module is arranged on any side of the pole group provided with a tab; S2, an insulating film is wrapped outside the multiple sides of the pole group, and the insulating film is hot-melted with a first plastic part to form a pole group unit; S3, the pole group unit is arranged in a battery shell; S4, a first cover plate module is arranged on the other side of the pole group; S5, the battery shell is finally welded with the first cover plate module and the second cover plate module; S6, a composite pole is arranged, and the composite pole is welded with the first cover plate module; and S7, current conduction between the composite pole and the tab is realized. Through the current conduction between the composite pole and the tab, the influence of other welding processes on the connection quality of the tab on this side and the composite pole is avoided, the tab on this side is stretched out of the battery shell to realize current conduction with the composite pole, the occupation of the internal space is reduced, and the space utilization is improved.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a battery assembly method and a battery. Background Technology

[0002] Lithium-ion batteries are a new type of high-energy battery based on the movement of lithium ions between the positive and negative electrodes. During charging, lithium ions are extracted from the positive electrode and inserted into the negative electrode through the electrolyte; during discharging, the reverse occurs, with lithium ions being extracted from the negative electrode and returning to the positive electrode, forming current to power devices. Due to their advantages such as high energy density, high voltage, wide operating temperature range, and long storage life, lithium-ion batteries have a wide range of applications, including electric vehicles, energy storage systems, and military equipment. With continuous development, lithium-ion batteries have evolved into various types, such as blade batteries, prismatic batteries, and large cylindrical batteries. Among them, blade batteries offer advantages such as high safety, high energy density, long lifespan, fast charging, good low-temperature performance, and low cost, making them highly competitive in the market. A blade battery includes electrode groups with tabs on both sides, a battery casing, and a cover module consisting of electrode posts, a bare aluminum plate, upper and lower plastic sheets, riveting blocks, and seals.

[0003] The traditional assembly process for blade batteries typically involves first inserting the terminals into the battery casing, then welding the terminals to the corresponding polarity tabs, followed by sequentially inserting the lower plastic and aluminum plates, with a portion of the terminals extending through the lower plastic and aluminum plates and protruding from the battery casing. After the aluminum plates are assembled, they are welded to the battery casing. Then, on the outer side of the aluminum plate corresponding to the protruding portion of the terminals, the upper plastic, sealing components, and riveting blocks are sequentially inserted, and the riveting blocks are welded to the aluminum plates and riveted to the terminals protruding from the aluminum plates, thus completing the assembly of the blade battery.

[0004] However, the blade battery assembled using this method has several drawbacks. First, the tabs and terminals need to be welded together first, followed by the welding of the aluminum plate to the battery casing, the welding of the riveting block to the aluminum plate, and the riveting of the riveting block to the terminals. This results in the already welded tabs and terminals being affected by adverse factors such as high temperature and vibration during the welding of the aluminum plate to the battery casing, the welding of the riveting block to the aluminum plate, and the riveting of the riveting block to the terminals. This reduces the welding quality between the terminals and tabs and lowers the product yield. Second, because this method also requires reserving space inside the battery casing to accommodate the terminals and the connection between the terminals and tabs, the tabs and terminals occupy a large amount of space inside the battery casing, limiting the volume of the electrode assembly and resulting in lower energy density. Summary of the Invention

[0005] The purpose of this invention is to provide a battery assembly method and a battery with high product yield and energy density.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] On the one hand, a battery assembly method is provided, wherein the battery assembled by the battery assembly method includes a battery casing, an electrode group, a first cover plate module, a composite terminal post, and a second cover plate module.

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

[0009] S1. The electrode assembly includes a first surface and a second surface with electrode tabs, and a plurality of side surfaces perpendicular to the first surface and the second surface. The second cover plate module includes an independent electrode post. The second cover plate module is installed on the first surface and / or the second surface of the electrode assembly, and the electrode tab on that side is welded to the independent electrode post.

[0010] S2. An insulating film is wrapped around the outside of the electrode group so that the insulating film covers the outside of the plurality of sides. The second cover plate module also includes a first plastic part for insulation protection. The insulating film and the first plastic part are heat-fused to form an electrode group unit.

[0011] S3. The battery casing is a double-sided open structure with a cavity. The electrode unit with the second cover module is installed into the cavity of the battery casing. The second cover module closes the opening on one side of the battery casing, and the second cover module is pre-welded to the battery casing through a plurality of spaced first pre-welding points.

[0012] S4. The first cover plate module includes a through structure for the tab to extend and a first insulating layer for isolating the first cover plate module from the tab. The first cover plate module is inserted into the opening on the other side of the battery casing. The tab on the other side of the electrode group passes through the through structure. The first cover plate module and the battery casing are pre-welded through multiple spaced second pre-welding points.

[0013] S5. Final weld the battery casing to the first cover plate module and the second cover plate module;

[0014] S6. The first cover plate module is also provided with a receiving groove on the side away from the electrode group. The composite electrode post is installed into the receiving groove and the composite electrode post is welded to the first cover plate module.

[0015] S7. Enable current conduction between the composite electrode post and the electrode tab.

[0016] Optionally, step S2 may further include the following steps:

[0017] S21. The battery further includes at least one protective side plate, and at least one of the protective side plates is pre-heat-melted to a predetermined position on the insulating film;

[0018] S22. The insulating film is wrapped around a plurality of the sides of the electrode assembly, and at least one of the protective side plates covers one of the sides of the electrode assembly;

[0019] S23. The overlapping area between the insulating film and the first plastic part is heat-melted.

[0020] Optionally, step S21 may further include the following steps:

[0021] S211. A positioning hole is made at the designated position of the insulating film;

[0022] S212. The protective side plate is provided with a positioning structure that cooperates with the positioning hole. The protective side plate is located at a set position of the insulating film, and the positioning structure is aligned with the positioning hole.

[0023] S213. The assembled protective side plate and the insulating film are heat-fused together.

[0024] Optionally, a plurality of spaced hot melt points are provided in the overlapping area between the insulating film and the first plastic part. The distance between the boundary of each hot melt point on the side away from the electrode group and the boundary of the overlapping area on the side away from the electrode group is L1, and satisfies 0.5mm≤L1≤3mm.

[0025] And / or, the distance between the boundary of each of the hot melting points facing the electrode group and the boundary of the overlapping area facing the electrode group is L2, and satisfies 0.5mm≤L2≤3mm.

[0026] Optionally, the first cover plate module includes a cover plate body and the first insulating layer;

[0027] The receiving groove is formed on the cover plate body, and the cover plate body is also provided with a insertion through hole disposed in the receiving groove;

[0028] The first insulating layer is injection molded onto the cover plate body and includes an upper insulating part, a lower insulating part, and a plug-in part. The upper insulating part is located on the side of the cover plate body away from the electrode group and is located in the receiving groove. The lower insulating part is located on the side of the cover plate body facing the electrode group and is located between the cover plate body and the electrode group. The plug-in part is inserted into the plug-in through hole and is used to connect the upper insulating part and the lower insulating part. The through structure penetrates the upper insulating part, the plug-in part, and the lower insulating part.

[0029] Optionally, step S6 further includes the following steps:

[0030] S61. The upper insulating part is provided with a mounting groove on the side opposite to the cover plate body. The battery also includes a connecting piece, which is inserted into the mounting groove.

[0031] S62. Bend the portion of the electrode tab extending out of the through structure and weld the bent electrode tab to the connecting piece;

[0032] S63. The battery also includes a sealing ring, which is inserted into the receiving groove.

[0033] S64. The composite pole is installed into the receiving groove, and the sealing ring is sandwiched between the composite pole and the first cover plate module.

[0034] S65. Weld the composite pole to the first cover plate module.

[0035] Optionally, step S7 further includes the following steps:

[0036] S71. The connecting piece is provided with a connecting boss protruding along the side of the composite pole facing the composite pole, and the composite pole is pre-welded and positioned on the connecting boss by a plurality of spaced third pre-welding points.

[0037] S72. Fully weld the composite pole to the connecting boss.

[0038] Optionally, step S65 further includes the following steps:

[0039] S651, the composite pole includes a pole body, a welding ring, and a second insulating layer for achieving an insulating connection between the pole body and the welding ring, wherein the welding ring is pre-welded and positioned in the receiving groove through a plurality of spaced fourth pre-welding points;

[0040] S652. Fully weld the welding ring into the receiving groove.

[0041] Optionally, in step S62, after the connecting piece is inserted into the mounting groove, the bent electrode tab is welded to the side of the connecting piece facing the first cover plate module, or the bent electrode tab is welded to the side of the connecting piece facing the composite electrode post.

[0042] On the other hand, a battery is provided, which is assembled using the battery assembly method described in any of the preceding claims.

[0043] The beneficial effects of this invention are:

[0044] This invention provides a battery assembly method. By setting a first cover module with a through structure and a first insulating layer on either side of the electrode assembly where the tabs are located, the tabs on that side extend out of the battery casing and connect with a composite terminal located outside the battery casing to conduct current. This eliminates the space occupied by connecting the tabs on one side to the composite terminal and the space occupied by the composite terminal extending into the battery casing. This reduces the space occupied and improves space utilization. It also provides space for increasing the size of the electrode assembly and improves energy density. Furthermore, when connecting the tabs on that side to the composite terminal, the sequence is after welding the first cover module to the battery casing and welding the composite terminal to the first cover module. This effectively avoids the influence of other welding processes on the connection quality between the already connected tabs and composite terminal, resulting in a higher product yield.

[0045] The present invention also provides a battery that, by assembling it using the battery assembly method described above, allows the volume of the electrode assembly to be further increased, thereby improving the energy density of the battery and increasing its power supply capacity. Attached Figure Description

[0046] Figure 1 This is a flowchart of the battery assembly method provided by the present invention;

[0047] Figure 2 This is an exploded view of the battery structure provided by the present invention;

[0048] Figure 3 This is a structural cross-sectional view of the first cover module side of the battery provided by the present invention;

[0049] Figure 4 This is a schematic diagram of the thermal fusion structure of the insulating film and the protective side plate in the battery provided by the present invention;

[0050] Figure 5 This is a schematic diagram showing the distribution of the hot melt points of the first plastic component and the insulating film in the battery provided by the present invention;

[0051] Figure 6 This is a schematic diagram showing the distribution of pre-welded points between the first cover plate module and the battery casing in the battery provided by the present invention;

[0052] Figure 7 This is an assembly diagram of the second cover plate module in the battery provided by the present invention;

[0053] Figure 8 This is a cross-sectional view of the structure of the second cover plate module in the battery provided by the present invention;

[0054] Figure 9 This is a schematic diagram of the battery cover body structure provided by the present invention;

[0055] Figure 10 This is a schematic diagram of the structure of the first insulating layer in the battery provided by the present invention.

[0056] In the picture:

[0057] 100. Second pre-welding point;

[0058] 1. Battery casing;

[0059] 2. Pole group; 21. Pole tab; 22. First surface; 23. Second surface; 24. Side surface;

[0060] 3. First cover plate module; 31. Cover plate body; 311. Receiving groove; 312. Insertion through hole; 32. First insulating layer; 321. Upper insulating part; 322. Lower insulating part; 323. Insertion part; 324. Mounting groove; 325. Through structure; 326. Shaping structure;

[0061] 4. Composite pole; 41. Pole body; 42. Welding ring; 43. Second insulation layer;

[0062] 5. Second cover plate module; 51. Independent pole post; 52. First plastic part; 53. Plain aluminum plate; 54. Second plastic part; 55. Sealing part; 56. Riveting block;

[0063] 6. Insulating film; 61. Positioning hole; 62. Hot melt point;

[0064] 7. Protective side panels;

[0065] 8. Connecting piece; 81. Connecting boss;

[0066] 9. Sealing ring. Detailed Implementation

[0067] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0068] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0069] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0070] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0071] The blade battery comprises a battery pack with tabs on both sides, a battery casing, and a cover module consisting of terminals, a bare aluminum plate, upper and lower plastic components, riveting blocks, and seals. Traditional assembly methods require welding the tabs to the terminals first, followed by welding the bare aluminum plate to the battery casing, the riveting blocks to the bare aluminum plate, and finally, riveting the riveting blocks to the terminals. This process exposes the already welded tabs and terminals to adverse factors such as high temperatures and vibrations during the welding of the bare aluminum plate to the battery casing, and the riveting of the riveting blocks to the terminals, thus reducing the welding quality between the terminals and tabs and lowering the product yield. Furthermore, this method requires reserving space inside the battery casing to accommodate the terminals and the connection between them, resulting in the tabs and terminals occupying a significant amount of internal space, limiting the volume of the battery pack and leading to lower energy density.

[0072] Therefore, in order to improve product yield, 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, an electrode group 2, a first cover plate module 3, a composite terminal 4, and a second cover plate module 5.

[0073] like Figures 1 to 10 As shown, the battery assembly method includes the following steps:

[0074] S1. The electrode assembly 2 includes a first surface 22 and a second surface 23 with electrode tabs 21, and a plurality of side surfaces 24 perpendicular to the first surface 22 and the second surface 23. The second cover plate module 5 includes an independent pole post 51. The second cover plate module 5 is installed on the first surface 22 and / or the second surface 23 of the electrode assembly 2, and the electrode tab 21 on that side is welded to the independent pole post 51.

[0075] S2. An insulating film 6 is wrapped around the outside of the electrode group 2, so that the insulating film 6 covers the outside of multiple sides 24. The second cover plate module 5 also includes a first plastic part 52 for insulation protection. The insulating film 6 and the first plastic part 52 are heat-fused to form an electrode group unit.

[0076] S3. The battery casing 1 has a double-sided open structure with a cavity. The electrode unit with the second cover module 5 is installed into the cavity of the battery casing 1. The second cover module 5 closes the opening on one side of the battery casing 1 and the second cover module 5 is pre-welded to the battery casing 1 through multiple spaced first pre-welding points.

[0077] S4. The first cover module 3 includes a through structure 325 for the tab 21 to extend out and a first insulating layer 32 for isolating the first cover module 3 from the tab 21. The first cover module 3 is installed into the opening on the other side of the battery casing 1. The tab 21 on the other side of the electrode group 2 passes through the through structure 325. The first cover module 3 and the battery casing 1 are pre-welded through multiple spaced second pre-welding points 100.

[0078] S5. Final weld the battery casing 1 to the first cover plate module 3 and the second cover plate module 5.

[0079] S6. The first cover plate module 3 is also provided with a receiving groove 311 on the side opposite to the electrode group 2. The composite electrode post 4 is installed into the receiving groove 311 so that the composite electrode post 4 is welded to the first cover plate module 3.

[0080] S7 enables current conduction between the composite pole 4 and the tab 21.

[0081] This battery assembly method involves setting a first cover module 3 with a through structure 325 and a first insulating layer 32 on either side of the electrode assembly 2 where the tab 21 is located. This allows the tab 21 on that side to conduct current through the composite terminal 4 located outside the battery casing 1 by extending out of the battery casing 1. This eliminates the space occupied by connecting the tab 21 to the composite terminal 4 on one side and the space occupied by the composite terminal 4 extending into the battery casing 1. This reduces the space occupied and improves the space utilization rate. On the other hand, it provides space for increasing the size of the electrode assembly 2 and improves the energy density. Furthermore, when conducting current through the tab 21 to the composite terminal 4 on that side, the sequence is after welding the first cover module 3 to the battery casing 1 and welding the composite terminal 4 to the first cover module 3. This effectively avoids the influence of other welding processes on the connection quality between the already connected tab 21 and composite terminal 4, resulting in a higher product yield.

[0082] In this embodiment, the second cover module 5 is a traditional riveted cover. In addition to the independent terminal 51 and the first plastic part 52, it also includes a light aluminum plate 53, a second plastic part 54, a sealing part 55 and a riveting block 56. Before assembling the battery, the second cover module 5, i.e. the riveted cover, can be assembled in advance. After the assembly is completed, the electrode tab 21 can be directly welded to the independent terminal 51 in the assembled second cover module 5.

[0083] Specifically, the steps include the following:

[0084] Ⅰ. The second plastic part 54 is bonded to the side of the aluminum plate 53 away from the electrode group 2 using structural adhesive;

[0085] II. The first plastic part 52 is bonded to the side of the aluminum plate 53 facing the electrode group 2 using structural adhesive;

[0086] III. The second plastic part 54 has a positioning groove on the side away from the light aluminum plate 53, and the rivet block 56 is inserted into the positioning groove.

[0087] IV. The independent pole 51 includes a pole body and a limiting part, and the sealing member 55 is sleeved on the pole body of the independent pole 51.

[0088] V. Insert the independent pole 51, and make the pole part of the independent pole 51 pass through the first plastic part 52, the light aluminum plate 53 and the second plastic part 54 in sequence, and finally insert it into the rivet block 56. At this time, the first plastic part 52 is clamped between the limiting part of the independent pole 51 and the light aluminum plate 53.

[0089] VI. Rivet the column part of the independent pole 51 to the riveting block 56 to complete the assembly of the second cover plate module 5.

[0090] The type of the second cover plate module 5 is not limited to the traditional riveted cover plate. In other embodiments, the second cover plate module 5 can also be a traditional welded cover plate or a traditional minimalist cover plate.

[0091] In addition, when the first cover plate module 3 and the second cover plate module 5 are pre-welded to the battery casing 1, the number of the first pre-welding points and the number of the second pre-welding points 100 can be freely set according to requirements. Taking the welding of the first cover plate module 3 and the battery casing 1 as an example, in this embodiment, since the first cover plate module 3 includes a large end face with a larger area and a small end face with a smaller area, the overlapping area formed by the different end faces and the battery casing 1 is also different. On the larger surface, at least three second pre-welding points 100 are provided, preferably five, and on the smaller surface... On the surface, at least one second pre-welding point 100 is provided, preferably three. When there are multiple second pre-welding points 100, it is necessary to ensure that the multiple second pre-welding points 100 are evenly distributed at intervals. When the first cover plate module 3 and the second cover plate module 5 are finally welded to the battery casing 1, the first cover plate module 3 and the battery casing 1 can be finally welded together first, and then the second cover plate module 5 and the battery casing 1 can be finally welded together. Alternatively, the first cover plate module 3 and the second cover plate module 5 can be finally welded together with the battery casing 1 simultaneously. The specific implementation method depends on the actual working environment.

[0092] Optionally, such as Figures 2 to 4 As shown, step S2 further includes the following steps:

[0093] S21, the battery also includes at least one protective side plate 7, which is pre-heat-melted into the insulating film 6 at a predetermined position;

[0094] S22. The insulating film 6 is wrapped around multiple sides 24 of the electrode group 2, and at least one protective side plate 7 is covered on one side 24 of the electrode group 2.

[0095] S23. The overlapping area between the insulating film 6 and the first plastic part 52 is heat-melted.

[0096] By heat-melting a protective side plate 7 onto the insulating film 6 before covering it, the protective side plate 7 can cover one side 24 of the electrode group 2 when the insulating film 6 is covered on the electrode group 2. This allows the electrode group 2 to be protected by the protective side plate 7 on the side 24 of the electrode group 2 when it is put into the housing, thus preventing scratches during the housing process.

[0097] The number of protective side plates 7 can be freely set according to the protection requirements. In this embodiment, four protective side plates 7 are provided, which correspond one-to-one with the four sides 24 of the electrode group 2, thereby improving the protection performance of the electrode group 2.

[0098] Optionally, such as Figures 2 to 4As shown, step S21 further includes the following steps:

[0099] S211. A positioning hole 61 is made at a predetermined position on the insulating film 6;

[0100] S212, The protective side plate 7 is provided with a positioning structure that cooperates with the positioning hole 61. The protective side plate 7 is located at the set position of the insulating film 6, and the positioning structure is aligned with the positioning hole 61.

[0101] S213. The assembled protective side plate 7 and insulating film 6 are heat-fused together.

[0102] By opening a positioning hole 61 at a set position on the insulating film 6 and setting a positioning structure on the protective side plate 7 that cooperates with the positioning hole 61, the accuracy of the hot-melt position of the protective side plate 7 is ensured, thereby avoiding the inability of the protective side plate 7 to provide effective protection when the insulating film 6 covers the electrode group 2 due to the inaccurate position of the protective side plate 7 after hot melting.

[0103] Optionally, such as Figure 2 , Figure 5 , Figure 8 As shown, a plurality of hot melt points 62 are provided in the overlapping area between the insulating film 6 and the first plastic part 52. The distance between the boundary of each hot melt point 62 on the side away from the electrode group 2 and the boundary of the overlapping area on the side away from the electrode group 2 is L1, and satisfies 0.5mm≤L1≤3mm.

[0104] By employing multiple spaced hot-melt points 62, the heat fusion between the insulating film 6 and the first plastic part 52 is achieved. This ensures a sufficiently wide range for the heat fusion process, guaranteeing a strong bond. Furthermore, compared to full heat fusion, the fusion area is smaller, thus shortening the time required for the heat fusion operation and improving efficiency. Simultaneously, by setting L1 as the distance between the boundary of each hot-melt point 62 on the side away from the electrode group 2 and the boundary of the overlapping area on the side away from the electrode group 2, and limiting L1 to satisfy 0.5mm ≤ L1 ≤ 3mm, a suitable distance is maintained between the hot-melt points 62 and the boundary of the overlapping area on the side away from the electrode group 2. This avoids insufficient operable area during heat fusion due to too small a distance, and also avoids loose connection of the area on the side of the hot-melt points 62 away from the electrode group 2 due to too large a distance.

[0105] In this embodiment, the first plastic part 52 includes a large end face with a larger area and a small end face with a smaller area. Therefore, the overlapping area formed by the different end faces and the insulating film 6 is also different. On the surface with a larger area, at least three spaced hot melt points 62 are provided, and on the surface with a smaller area, at least one hot melt point 62 is provided. The shape of the hot melt points 62 can be freely set according to requirements, such as circular, elliptical, or polygonal. When there are multiple hot melt points 62, it is necessary to ensure that the multiple spaced hot melt points 62 are evenly distributed.

[0106] The distance L1 between the boundary of each hot melting point 62 on the side away from the electrode group 2 and the boundary of the overlapping area on the side away from the electrode group 2 can be any value between 0.5mm and 3mm or any range between two values, such as 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, etc.

[0107] Optionally, such as Figure 2 , Figure 5 , Figure 8 As shown, the distance between the boundary of each hot melting point 62 facing the electrode group 2 and the boundary of the overlapping area facing the electrode group 2 is L2, and satisfies 0.5mm≤L2≤3mm.

[0108] By employing multiple spaced hot-melt points 62, the heat fusion between the insulating film 6 and the first plastic part 52 is achieved. This ensures a sufficiently wide range for the heat fusion process, guaranteeing a strong bond, and compared to full heat fusion, it results in a shorter fusion time and higher efficiency. Simultaneously, by setting L2 as the distance between the boundary of each hot-melt point 62 facing the electrode group 2 and the boundary of the overlapping area facing the electrode group 2, and limiting L2 to satisfy 0.5mm ≤ L2 ≤ 3mm, a suitable distance is maintained between the hot-melt points 62 and the boundary of the overlapping area facing the electrode group 2. This avoids both insufficient space for heat fusion due to too small a distance and loose bonding due to too large a distance.

[0109] In this embodiment, the first plastic part 52 includes a large end face with a larger area and a small end face with a smaller area. Therefore, the overlapping area formed by the different end faces and the insulating film 6 is also different. At least three hot melt points 62 are provided on the larger surface and at least one hot melt point 62 is provided on the smaller surface. The shape of the hot melt points 62 can be freely set according to requirements, such as circular, elliptical, or polygonal. When there are multiple hot melt points 62, it is necessary to ensure that the multiple spaced hot melt points 62 are evenly distributed.

[0110] The distance L2 between the boundary of each hot melting point 62 facing the electrode group 2 and the boundary of the overlapping area facing the electrode group 2 can be any value between 0.5mm and 3mm or any range between two values, such as 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, etc.

[0111] In this embodiment, to verify the impact of distance dimensions L1 and L2 on the quality of the assembled product in the battery assembly method, as shown in Table 1, six sets of examples and four sets of comparative examples are provided for verification. Since the second cover module 5 is composed of independent electrode posts 51, a first plastic part 52, a light aluminum plate 53, a second plastic part 54, a sealing part 55, and a welding station 56, the distance dimension L1 between the boundary of the hot melt point 62 away from the electrode group 2 and the boundary of the overlapping area away from the electrode group 2 is essentially the distance between the boundary of the hot melt point 62 away from the electrode group 2 and the boundary of the overlapping area of ​​the first plastic part 52 away from the electrode group 2. Similarly, the distance dimension L2 between the boundary of the hot melt point 62 facing the electrode group 2 and the boundary of the overlapping area facing the electrode group 2 is essentially the distance between the boundary of the hot melt point 62 facing the electrode group 2 and the boundary of the overlapping area of ​​the first plastic part 52 facing the electrode group 2.

[0112] Table 1

[0113]

[0114] In Example 1, the distance L1 between the boundary of the hot melting point 62 on the side away from the electrode group 2 and the boundary of the overlapping area on the side away from the electrode group 2 is set to 0.5mm, and the distance L2 between the boundary of the hot melting point 62 on the side facing the electrode group 2 and the boundary of the overlapping area on the side facing the electrode group 2 is set to 0.5mm. After the battery is assembled according to the above data, it is verified that the insulating film 6 is not damaged and does not fall off after the battery is disassembled.

[0115] In Example 2, the distance L1 between the boundary of the hot melting point 62 on the side away from the electrode group 2 and the boundary of the overlapping area on the side away from the electrode group 2 is set to 2mm, and the distance L2 between the boundary of the hot melting point 62 on the side facing the electrode group 2 and the boundary of the overlapping area on the side facing the electrode group 2 is set to 2mm. After the battery is assembled according to the above data, it is verified that the insulating film 6 is not damaged and does not fall off after the battery is disassembled.

[0116] In Example 3, the distance L1 between the boundary of the hot melting point 62 on the side away from the electrode group 2 and the boundary of the overlapping area on the side away from the electrode group 2 is set to 1 mm, and the distance L2 between the boundary of the hot melting point 62 on the side facing the electrode group 2 and the boundary of the overlapping area on the side facing the electrode group 2 is set to 3 mm. After the battery is assembled according to the above data, it is verified that the insulating film 6 is not damaged and does not fall off after the battery is disassembled.

[0117] In Example 4, the distance L1 between the boundary of the hot melting point 62 on the side away from the electrode group 2 and the boundary of the overlapping area on the side away from the electrode group 2 is set to 3mm, and the distance L2 between the boundary of the hot melting point 62 on the side facing the electrode group 2 and the boundary of the overlapping area on the side facing the electrode group 2 is set to 1mm. After the battery is assembled according to the above data, it is verified that the insulating film 6 is not damaged and does not fall off after the battery is disassembled.

[0118] In Example 5, the distance L1 between the boundary of the hot melting point 62 on the side away from the electrode group 2 and the boundary of the overlapping area on the side away from the electrode group 2 is set to 1.5 mm, and the distance L2 between the boundary of the hot melting point 62 on the side facing the electrode group 2 and the boundary of the overlapping area on the side facing the electrode group 2 is set to 2.5 mm. After the battery is assembled according to the above data, it is verified that the insulating film 6 is not damaged and does not fall off after the battery is disassembled.

[0119] In Example 6, the distance L1 between the boundary of the hot melt point 62 on the side away from the electrode group 2 and the boundary of the overlapping area on the side away from the electrode group 2 is set to 2.5 mm, and the distance L2 between the boundary of the hot melt point 62 on the side facing the electrode group 2 and the boundary of the overlapping area on the side facing the electrode group 2 is set to 1.5 mm. After the battery is assembled according to the above data, it is verified that the insulating film 6 is not damaged and does not fall off after the battery is disassembled.

[0120] As can be seen from Examples 1 to 6, when the distance L1 between the boundary of the hot melting point 62 on the side away from the electrode group 2 and the boundary of the overlapping area on the side away from the electrode group 2 satisfies the range of 0.5mm≤L1≤3mm, and the distance L2 between the boundary of the hot melting point 62 on the side facing the electrode group 2 and the boundary of the overlapping area on the side facing the electrode group 2 satisfies the range of 0.5mm≤L2≤3mm, the battery assembled by this battery assembly method, after disassembly, shows that the insulating film 6 is not damaged or falls off, and has high product quality.

[0121] In Comparative Example 1, the distance L1 between the boundary of the hot melt point 62 on the side away from the electrode group 2 and the boundary of the overlapping area on the side away from the electrode group 2 was set to 0.1 mm, and the distance L2 between the boundary of the hot melt point 62 on the side facing the electrode group 2 and the boundary of the overlapping area on the side facing the electrode group 2 was set to 1 mm. After the battery was assembled according to the above data, it was found that the insulating film 6 was peeling off.

[0122] As can be seen from Comparative Example 1, when the distance L1 between the boundary of the hot melt point 62 on the side away from the electrode group 2 and the boundary of the overlapping area on the side away from the electrode group 2 is less than the minimum value of 0.5mm≤L1≤3mm, the hot melt point 62 is too close to the upper edge of the overlapping area of ​​the first plastic part 52, causing some hot melt points 62 to exceed the upper edge of the insulating film 6. This results in insufficient hot melt area between the insulating film 6 and the first plastic part 52, which leads to the problem of the insulating film 6 falling off, resulting in poor insulation protection performance of the assembled battery.

[0123] In Comparative Example 2, the distance L1 between the boundary of the hot melt point 62 on the side away from the electrode group 2 and the boundary of the overlapping area on the side away from the electrode group 2 is set to 1 mm, and the distance L2 between the boundary of the hot melt point 62 on the side facing the electrode group 2 and the boundary of the overlapping area on the side facing the electrode group 2 is set to 0.1 mm. After the battery is assembled according to the above data, it is verified that the insulating film 6 and the first plastic part 52 have melted through, resulting in a short circuit.

[0124] As can be seen from Comparative Example 2, when the distance L2 between the boundary of the hot melt point 62 facing the electrode group 2 and the boundary of the overlapping area facing the electrode group 2 is less than the minimum value of 0.5mm≤L2≤3mm, the hot melt point 62 is close to the lower edge of the overlapping area of ​​the first plastic part 52, causing part of the hot melt point 62 to extend beyond the lower edge of the first plastic part 52. This results in a melting and breaking phenomenon between the insulating film 6 and the first plastic part 52, which causes a short circuit and leads to poor insulation protection performance of the assembled battery.

[0125] In Comparative Example 3, the distance L1 between the boundary of the hot melt point 62 on the side away from the electrode group 2 and the boundary of the overlapping area on the side away from the electrode group 2 is set to 4mm, and the distance L2 between the boundary of the hot melt point 62 on the side facing the electrode group 2 and the boundary of the overlapping area on the side facing the electrode group 2 is set to 1mm. After the battery is assembled according to the above data, it is verified that the insulating film 6 is located in the area between the hot melt point 62 and the upper edge of the overlapping area of ​​the first plastic part 52, and is not tightly connected to the first plastic part 52, resulting in the insulating film 6 having an edge flipped up.

[0126] As can be seen from Comparative Example 3, when the distance L1 between the boundary of the hot melt point 62 on the side away from the electrode group 2 and the boundary of the overlapping area on the side away from the electrode group 2 is greater than the maximum value of 0.5mm≤L1≤3mm, the distance between the hot melt point 62 and the upper edge of the overlapping area of ​​the first plastic part 52 is relatively far. As a result, the insulating film 6 is located in the area between the hot melt point 62 and the upper edge of the overlapping area of ​​the first plastic part 52, and is not tightly connected to the first plastic part 52. This causes the insulating film 6 to have an edge flipped up, which does not meet the usage requirements.

[0127] In Comparative Example 4, the distance L1 between the boundary of the hot melt point 62 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 L2 between the boundary of the hot melt point 62 facing the electrode group 2 and the boundary of the overlapping area facing the electrode group 2 is set to 4 mm. After the battery is assembled according to the above data, it is verified that the insulating film 6 is located in the area between the hot melt point 62 and the lower edge of the overlapping area of ​​the first plastic part 52, and is not tightly connected to the first plastic part 52, and there is a gap between the insulating film 6 and the electrode group 2.

[0128] As can be seen from Comparative Example 4, when the distance L2 between the boundary of the hot melt point 62 facing the electrode group 2 and the boundary of the overlapping area facing the electrode group 2 is greater than the maximum value of 0.5mm≤L2≤3mm, the distance between the hot melt point 62 and the lower edge of the overlapping area of ​​the first plastic part 52 is relatively far. This results in the insulating film 6 being located in the area between the hot melt point 62 and the lower edge of the overlapping area of ​​the first plastic part 52, and not being tightly connected to the first plastic part 52. This weakens the wrapping and binding force of the insulating film 6 on the electrode group 2, making it easy for gaps to form between the insulating film 6 and the electrode group 2, which does not meet the usage requirements.

[0129] Optionally, such as Figure 2 , Figure 3 , Figure 9 , Figure 10 As shown, the first cover plate module 3 includes a cover plate body 31 and a first insulating layer 32. A receiving groove 311 is formed on the cover plate body 31. The cover plate body 31 is also provided with a plug-in through hole 312 in the receiving groove 311. The first insulating layer 32 is injection molded on the cover plate body 31 and includes an upper insulating part 321, a lower insulating part 322 and a plug-in part 323. The upper insulating part 321 is provided 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 part 322 is provided on the side of the cover plate body 31 facing the pole group 2 and is located between the cover plate body 31 and the pole group 2. The plug-in part 323 is inserted into the plug-in through hole 312 and is used to connect the upper insulating part 321 and the lower insulating part 322. The through structure 325 passes through the upper insulating part 321, the plug-in part 323 and the lower insulating part 322.

[0130] By setting a first insulating layer 32 consisting of an upper insulating part 321, a lower insulating part 322, and a plug-in part 323, with the upper insulating part 321 located on the side of the cover plate body 31 away from the electrode group 2, the lower insulating part 322 located on the side of the cover plate body 31 facing the electrode group 2, the plug-in part 323 inserted into the plug-in through hole 312, and the through structure 325 penetrating through the upper insulating part 321, the plug-in part 323, and the lower insulating part 322, the first insulating layer 32 provides insulation protection for both sides of the cover plate body 31 and the inside of the plug-in through hole 312, isolating the electrode tab 21 from the cover plate body 31, preventing the electrode tab 21 from directly contacting the cover plate body 31 when passing through it, thus avoiding a short circuit and ensuring safety and protection.

[0131] In this embodiment, the first insulating layer 32 is a plastic part directly molded onto the cover plate body 31 by injection molding. Compared with the second cover plate module 5 using the traditional riveted cover plate method, 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 321, the insertion part 323, and the lower insulating part 322 are integrated structural parts formed simultaneously by injection molding. In other embodiments, the upper insulating part 321, the insertion part 323, and the lower insulating part 322 can also be injection molded separately and then inserted into each other to form a split first insulating layer 32.

[0132] Optionally, such as Figure 3 As shown, the lower insulating part 322 has a shaping structure 326 on the side facing the electrode group 2, which corresponds to the through structure 325. The shaping structure 326 is a horn shape with the opening gradually narrowing away from the electrode group 2. In step S4, the multiple gathered tabs 21 on the electrode group 2 are better supported and fixed, the gathered state of the tabs 21 is improved, and the problem of short circuit caused inside the battery due to poor gathering effect of the tabs 21 is avoided.

[0133] Optionally, such as Figure 2 , Figure 3 , Figure 9 , Figure 10 As shown, step S6 further includes the following steps:

[0134] S61. The upper insulating part 321 is provided with a mounting groove 324 on the side opposite to the cover plate body 31. The battery also includes a connecting piece 8, which is inserted into the mounting groove 324.

[0135] S62, bend the part of the electrode tab 21 that extends through the structure 325, and weld the bent electrode tab 21 to the connecting piece 8;

[0136] S63, the battery also includes a sealing ring 9, which is inserted into the receiving groove 311;

[0137] S64. The composite pole 4 is installed into the receiving groove 311, and the sealing ring 9 is clamped between the composite pole 4 and the first cover plate module 3.

[0138] S65, welded composite pole 4 and first cover plate module 3.

[0139] By setting the connecting piece 8 and welding the electrode 21 to the connecting piece 8, the position of the electrode 21 can be fixed in advance by using the connecting piece 8, ensuring the accuracy of the position of the electrode 21 during subsequent operations, and avoiding the influence of the current conduction effect between the electrode 21 and the composite electrode post 4 due to the misalignment of the electrode 21.

[0140] Optionally, such as Figure 2 , Figure 3 , Figure 9 , Figure 10 As shown, step S7 further includes the following steps:

[0141] S71, the connecting piece 8 is provided with a connecting boss 81 protruding close to the composite pole 4 on the side facing the composite pole 4, and the composite pole 4 is pre-welded and positioned on the connecting boss 81 by a plurality of spaced third pre-welding points.

[0142] S72. Fully weld the composite pole 4 to the connecting boss 81.

[0143] A connecting boss 81 is provided on the side of the connecting piece 8 facing the composite pole 4, which facilitates welding between the connecting piece 8 and the composite pole 4. The size and shape of the connecting boss 81 can be freely set according to requirements, ensuring sufficient welding area between the connecting boss 81 and the composite pole 4. In this embodiment, the connecting boss 81 is a frustum.

[0144] In addition, the composite pole 4 is pre-welded to the connecting boss 81 through multiple spaced third pre-welding points. This ensures that the relative position between the composite pole 4 and the connecting boss 81 is initially positioned before full welding, thus ensuring the accuracy of their post-weld positions during full welding, guaranteeing welding quality. Furthermore, even if the initial positioning is incorrect, it is easy to separate and reposition them, enabling recycling and reducing the scrap rate of the product.

[0145] Optionally, such as Figure 2 , Figure 3 , Figure 9 , Figure 10 As shown, step S65 further includes the following steps:

[0146] S651, 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. The welding ring 42 is pre-welded and positioned in the receiving groove 311 by multiple spaced fourth pre-welding points.

[0147] S652. Fully weld the welding ring 42 into the receiving groove 311.

[0148] First, the welding ring 42 is pre-welded into the receiving groove 311 through multiple spaced fourth pre-welding points. This ensures that the relative position of the welding ring 42 in the receiving groove 311 is positioned before full welding. Even if the initial positioning is incorrect, it is easy to separate and reposition the two, achieving recycling and reducing the scrap rate of the product. The number, size, and shape of the fourth pre-welding points used to pre-weld the welding ring 42 can be freely set according to actual needs. Furthermore, the second insulating layer 43 is formed by injection molding to insulate and connect the pole body 41 and the welding ring 42, thus making the pole body 41, the second insulating layer 43, and the welding ring 42 into a whole. Compared with the second cover plate module 5 using the traditional riveted cover plate form, the separate second plastic part 54 and riveting block 56 are eliminated, thereby reducing the number of parts and simplifying the assembly process.

[0149] Optionally, in step S62, after the connecting piece 8 is inserted into the mounting groove 324, the bent electrode tab 21 is welded to the side of the connecting piece 8 facing the first cover plate module 3, or the bent electrode tab 21 is welded to the side of the connecting piece 8 facing the composite electrode post 4. This is to adapt to various working environments and facilitate welding operations between the bent electrode tab 21 and the connecting piece 8. In this embodiment, the bent electrode tab 21 is welded to the side of the connecting piece 8 facing the composite electrode post 4.

[0150] In this embodiment, a battery is also provided, which is assembled using the battery assembly method described above. By assembling the battery using the battery assembly method described above, the volume of the electrode group 2 can be further increased, thereby improving the energy density of the battery and increasing its power supply capacity.

[0151] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should 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 using the battery assembly method includes a battery casing, electrode assembly, a first cover plate module, composite terminals, and a second cover plate module. The battery assembly method includes the following steps: S1. The electrode assembly includes a first surface and a second surface with electrode tabs, and a plurality of side surfaces perpendicular to the first surface and the second surface. The second cover plate module includes an independent electrode post. The second cover plate module is installed on the first surface and / or the second surface of the electrode assembly, and the electrode tab on that side is welded to the independent electrode post. S2. An insulating film is wrapped around the outside of the electrode group so that the insulating film covers the outside of the plurality of sides. The second cover plate module also includes a first plastic part for insulation protection. The insulating film and the first plastic part are heat-fused to form an electrode group unit. S3. The battery casing is a double-sided open structure with a cavity. The electrode unit with the second cover module is installed into the cavity of the battery casing. The second cover module closes the opening on one side of the battery casing, and the second cover module is pre-welded to the battery casing through a plurality of spaced first pre-welding points. S4. The first cover plate module includes a through structure for the tab to extend and a first insulating layer for isolating the first cover plate module from the tab. The first cover plate module is inserted into the opening on the other side of the battery casing. The tab on the other side of the electrode group passes through the through structure. The first cover plate module and the battery casing are pre-welded through multiple spaced second pre-welding points. S5. Final weld the battery casing to the first cover plate module and the second cover plate module; S6. The first cover plate module is also provided with a receiving groove on the side away from the electrode group. The composite electrode post is installed into the receiving groove and the composite electrode post is welded to the first cover plate module. S7. Enable current conduction between the composite electrode post and the electrode tab; The first cover plate module includes a cover plate body and the first insulating layer; The receiving groove is formed on the cover plate body, and the cover plate body is also provided with a insertion through hole disposed in the receiving groove; The first insulating layer is injection molded onto the cover plate body and includes an upper insulating part, a lower insulating part, and a plug-in part. The upper insulating part is located on the side of the cover plate body away from the electrode group and is located in the receiving groove. The lower insulating part is located on the side of the cover plate body facing the electrode group and is located between the cover plate body and the electrode group. The plug-in part is inserted into the plug-in through hole and is used to connect the upper insulating part and the lower insulating part. The through structure penetrates the upper insulating part, the plug-in part, and the lower insulating part. Step S6 also includes the following steps: S61. The upper insulating part is provided with a mounting groove on the side opposite to the cover plate body. The battery also includes a connecting piece, which is inserted into the mounting groove. S62. Bend the portion of the electrode tab extending out of the through structure and weld the bent electrode tab to the connecting piece; S63. The battery also includes a sealing ring, which is inserted into the receiving groove. S64. The composite pole is installed into the receiving groove, and the sealing ring is sandwiched between the composite pole and the first cover plate module. S65. Weld the composite pole to the first cover plate module.

2. The battery assembly method according to claim 1, characterized in that, Step S2 also includes the following steps: S21. The battery further includes at least one protective side plate, and at least one of the protective side plates is pre-heat-melted to a predetermined position on the insulating film; S22. The insulating film is wrapped around a plurality of the sides of the electrode assembly, and at least one of the protective side plates covers one of the sides of the electrode assembly; S23. The overlapping area between the insulating film and the first plastic part is heat-melted.

3. The battery assembly method according to claim 2, characterized in that, Step S21 also includes the following steps: S211. A positioning hole is made at the designated position of the insulating film; S212. The protective side plate is provided with a positioning structure that cooperates with the positioning hole. The protective side plate is located at a set position of the insulating film, and the positioning structure is aligned with the positioning hole. S213. The assembled protective side plate and the insulating film are heat-fused together.

4. The battery assembly method according to claim 2, characterized in that, The overlapping area between the insulating film and the first plastic part is provided with a plurality of spaced hot melt points. The distance between the boundary of each hot melt point on the side away from the electrode group and the boundary of the overlapping area on the side away from the electrode group is L1, and satisfies 0.5mm≤L1≤3mm. And / or, the distance between the boundary of each of the hot melting points facing the electrode group and the boundary of the overlapping area facing the electrode group is L2, and satisfies 0.5mm≤L2≤3mm.

5. The battery assembly method according to claim 1, characterized in that, Step S7 also includes the following steps: S71. The connecting piece is provided with a connecting boss protruding along the side of the composite pole facing the composite pole, and the composite pole is pre-welded and positioned on the connecting boss by a plurality of spaced third pre-welding points. S72. Fully weld the composite pole to the connecting boss.

6. The battery assembly method according to claim 1, characterized in that, Step S65 also includes the following steps: S651, the composite pole includes a pole body, a welding ring, and a second insulating layer for achieving an insulating connection between the pole body and the welding ring, wherein the welding ring is pre-welded and positioned in the receiving groove through a plurality of spaced fourth pre-welding points; S652. Fully weld the welding ring into the receiving groove.

7. The battery assembly method according to claim 1, characterized in that, In step S62, after the connecting piece is installed in the mounting groove, the bent electrode tab is welded to the side of the connecting piece facing the first cover plate module, or the bent electrode tab is welded to the side of the connecting piece facing the composite electrode post.

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

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