A method of assembling a battery pack and a battery pack

Abstract

This application provides a method for assembling a combined battery and a combined battery. The method includes: S1: selecting two electrode groups; assembling end plates and single-pole cover plates at both ends of each electrode group, and extending the positive and negative electrode tabs to their respective opposite end plates or single-pole cover plates; S2: selecting a cover plate assembly; electrically connecting the positive electrode tab of one electrode group to the positive electrode connection part of the cover plate assembly, and electrically connecting the negative electrode tab of the other electrode group to the negative electrode connection part of the cover plate assembly. The steps of the above combined battery assembly method are reasonable, completing the assembly of the end plates at the electrode groups and the cover plate assembly; adjacent battery cells are connected by the cover plate assembly, eliminating the need to set up crossbeams and various electrical connectors between them; multiple combined batteries are arranged to form a battery module, which, when used in a battery pack, reduces the space occupied inside the battery pack and reliably ensures the volumetric energy density of the battery pack.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a method for assembling a combined battery, and also to a combined battery assembled by the above-described method. Background Technology

[0002] Existing battery packs typically incorporate crossbeams and longitudinal beams to divide the pack into multiple spaces, each housing a battery module. This arrangement, with crossbeams or longitudinal beams between two battery modules, occupies a significant amount of space within the battery pack. Furthermore, to achieve the one-to-one electrical connection between the two battery cells within two modules, busbars, voltage sensors (CCS), and other data acquisition components are required on both sides of each battery cell, resulting in high space requirements and costs, and negatively impacting the battery's volumetric energy density. Maximizing the utilization of the battery pack's internal space to improve volumetric energy density and assembly efficiency has become a key technological challenge for the industry. The assembly method between adjacent battery cells within the battery pack is a crucial element in achieving this goal. Summary of the Invention

[0003] In view of this, the purpose of this application is to provide a method for assembling a combined battery and a combined battery, which solves the problem of high space occupation and cost caused by setting up a large number of structural components in the internal space of the battery pack.

[0004] To achieve the above objectives, this application provides the following technical solution: A method for assembling a combined battery includes fixing and electrically connecting two battery cells with opposite first openings in the battery casing using a cover plate assembly, wherein end plates are provided on both opposite sides of the cover plate assembly; the method for assembling a combined battery includes: S1: Select two pole groups with positive and negative electrodes arranged opposite each other; each pole group is equipped with end plates at both ends, and the positive electrode extends out to the end plate opposite to it, and the negative electrode extends out to the end plate opposite to it; S2: Select the cover plate assembly with positive and negative electrode connections respectively on opposite sides; electrically connect the positive electrode tab of one of the electrode groups to the positive electrode connection of the cover plate assembly, and electrically connect the negative electrode tab of the other electrode group to the negative electrode connection of the cover plate assembly.

[0005] Optionally, in the above-described battery assembly method, after step S2, the battery assembly method includes: S3: The electrical connection between the positive electrode tab and the positive electrode connection part is welding, and protective adhesive tape for positive electrode welding is applied at the welding position; the electrical connection between the negative electrode tab and the negative electrode connection part is welding, and protective adhesive tape for negative electrode welding is applied at the welding position. And / or, The electrode group includes multiple sides perpendicular to the cover plate assembly; step A1 is included before step S2; A1: In the two electrode groups, each side of the electrode group is covered with a Mylar film.

[0006] Optionally, in the above-mentioned battery assembly method, In step A1, at least one side is provided with a side plate. The side plate is first thermally fused with the Mylar film to form an inner insulation component, and then the inner insulation component is wrapped around the side. And / or, After step S2, the combined battery assembly method includes step A2; A2: In the two electrode groups, the Mylar film of each electrode group is thermally fused to the cover plate on the opposite side thereto; And / or, The order of steps S1 and A1 is not limited.

[0007] Optionally, in the above-described battery assembly method, the two opposite ends of the cover plate assembly are respectively formed with housing assembly portions arranged circumferentially thereon; after step S3, the battery assembly method includes: S4: Select two battery casings with the first opening and the second opening facing each other; assemble the two battery casings one-to-one onto the outside of the two electrode groups, and make the first opening opposite to the casing assembly part; S5: Fix the two first openings of the two battery casings to the two casing assembly parts respectively.

[0008] Optionally, in the above-mentioned battery assembly method, Before step S4, the combined battery assembly method includes step A3; A3: unfolding the two electrode groups in a side-by-side arrangement direction; And / or, The housing assembly has a stepped surface, and the end of the enclosure of the first opening abuts against the stepped surface and is welded to the outer periphery where the two abut.

[0009] Optionally, in the above-described battery assembly method, after step S5, the battery assembly method includes: S6: Select two single-pole cover plates with opposite polarities, select a single-pole cover plate with the same polarity as the tab at the second opening of the pole group, and electrically connect the single-pole cover plate to the tab on its opposite side. S7: Fix the two second openings of the two battery casings to the two single-pole cover plates respectively.

[0010] Optionally, in the above-mentioned battery assembly method, The fixed connection between the first opening and the housing assembly includes pre-spot welding and full welding; The fixed connection between the second opening and the single-pole cover plate includes pre-spot welding and full welding.

[0011] Optionally, in the above-described battery assembly method, the assembly method of the electrode group includes: G1: Stack the positive electrode, separator, and negative electrode in sequence; G2: Pre-solder the positive electrode tab and the negative electrode tab; G3: Apply positive electrode tab tape to the position where the positive electrode tab is pre-welded; apply negative electrode tab tape to the position where the negative electrode tab is pre-welded.

[0012] Optionally, in the above-mentioned battery assembly method, The cover plate assembly includes two cover plate units; the positive electrode connection part and the negative electrode connection part are an integral structure or an electrically connected separate structure, the positive electrode connection part and the negative electrode connection part are respectively passed through the two cover plate units, and the two cover plate units are fixed. or, The cover plate assembly includes a cover plate unit; the positive electrode connection part and the negative electrode connection part are an integral structure or electrically connected separate structures, and the positive electrode connection part and the negative electrode connection part pass through the cover plate unit.

[0013] A battery pack is assembled using the battery pack assembly method described above.

[0014] The combined battery assembly method and combined battery of this application provide an assembly method for obtaining combined batteries. By using a cover plate assembly, the positive electrode of one electrode group is electrically connected to the negative electrode of another electrode group, that is, the positive electrode of one battery cell is electrically connected to the negative electrode of another battery cell (i.e., in series). The steps of the above combined battery assembly method are in a reasonable order, completing the assembly of the end plate at the electrode tabs of the electrode group and the cover plate assembly, and completing the electrical connection of the electrode tabs of the electrode group at the cover plate assembly. The assembly steps on both sides of the cover plate assembly can be performed sequentially or simultaneously; preferably, they are performed simultaneously, which can optimize the process flow and ensure assembly efficiency. The combined battery obtained by this combined battery assembly method has a compact structure and small space occupation due to the compact structure of the cover plate assembly, which in turn makes the combined battery structure compact and occupies a small space. It also avoids setting crossbeams or longitudinal beams between two adjacent battery cells, as well as setting busbars, voltage connectors such as CCS, and acquisition devices on both sides of each battery cell. When multiple of the above combined batteries are arranged to form a battery module, the battery module can reduce the space occupied inside the battery pack when it is used in the battery pack, and reliably ensure the volumetric energy density of the battery pack. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0016] Figure 1 This is an exploded view of the combined battery according to an embodiment of this application.

[0017] Figure 2 This is a partial view of the cover plate assembly according to an embodiment of this application.

[0018] Figure 3 This is a partial view of a cover plate assembly according to another embodiment of this application.

[0019] Figure 4 This is a step diagram of the combined battery assembly method according to an embodiment of this application.

[0020] superior Figures 1-4 middle: 1. Cover plate assembly; 2. Battery cell; 3. End plate; 11. Cover plate unit; 12. Pole post connection part; 21. Battery casing; 22. Electrode assembly; 23. Single electrode cover; 24. Single electrode end plate; 25. Mylar film; 26. Side plate; 121. Positive electrode connection part; 122. Negative electrode connection part. Detailed Implementation

[0021] This application provides a method for assembling a combined battery and a combined battery, which solves the problem of high space occupation and cost caused by setting up a large number of structural components in the internal space of the battery pack.

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] like Figures 1-4As shown in the figure, this application provides a method for assembling a combined battery, through which a combined battery is obtained. The combined battery includes two battery cells 2; each battery cell 2 includes a battery casing 21 and an electrode assembly 22 disposed within the battery casing 21; both battery casings 21 have a first opening at their adjacent ends. The combined battery also includes a cover assembly 1 disposed between the two battery cells 2, with the opposite sides of the cover assembly 1 sealing the two first openings of the two battery casings 21 respectively. Optionally, the battery cells 2 are blade batteries, with the positive and negative electrodes of the blade batteries located at opposite ends of the blade batteries. The parallel arrangement direction of the two battery cells 2 in the combined battery is parallel to the direction from the positive to the negative electrode of the battery cells 2.

[0024] The battery assembly method secures and electrically connects two opposing battery cells 2 within the first opening of the battery casing 21 via a cover assembly 1. End plates 3 are respectively provided on opposite sides of the cover assembly 1. The battery assembly method includes: S1: Select two electrode groups 22 with positive and negative electrode tabs arranged opposite each other; each electrode group 22 is equipped with end plates 3 and single-end plates 24 at both ends, and the positive electrode tab extends out of the positive end plate 3 or single-end plate 24, and the negative electrode tab extends out of the negative single-end plate 24 or end plate 3 (specifically, in the two battery cells 2, the positive electrode tab of the electrode group 22 of one battery cell 2 extends out of the end plate 3 located on the side where the positive electrode connection part 121 of the cover plate assembly 1 is located, and the negative electrode tab extends out of the single-end plate 24 located on its side; the positive electrode tab of the other battery cell 2 extends out of the other single-end plate 24 located on its side, and the negative electrode tab extends out of the end plate 3 located on the side where the negative electrode connection part 122 of the cover plate assembly 1 is located). S2: Select a cover plate assembly 1 with a positive electrode connection part 121 and a negative electrode connection part 122 respectively, which are located opposite each other; connect the positive electrode tab of one electrode group 22 to the positive electrode connection part 121 of the cover plate assembly 1, and connect the negative electrode tab of the other electrode group 22 to the negative electrode connection part 122 of the cover plate assembly 1.

[0025] This application specifically provides a battery assembly method for obtaining a combined battery. By using a cover plate assembly 1, the positive electrode of one electrode group 22 is electrically connected to the negative electrode of another electrode group 22, that is, the positive electrode of one battery cell 2 is electrically connected to the negative electrode of another battery cell 2 (i.e., in series). The above-described battery assembly method has a reasonable sequence of steps, completing the assembly of the end plate 3 at the electrode tabs of the electrode group 22 and the cover plate assembly 1, and completing the electrical connection of the electrode tabs of the electrode group 22 at the cover plate assembly 1. The assembly steps on both sides of the cover plate assembly 1 can be performed sequentially or simultaneously; preferably, they are performed simultaneously, which optimizes the process flow and ensures assembly efficiency.

[0026] The combined battery assembly method obtained by this method results in a compact and space-saving battery pack due to the compact structure and small volume of the cover plate assembly 1. It also avoids the need for crossbeams or longitudinal beams between adjacent battery cells 2, and the installation of busbars, CCS voltage connectors, and data acquisition components on both sides of each battery cell 2. (Because the sides of the two battery cells 2 facing each other in the two battery modules are fixed and electrically connected by the cover plate assembly 1, there is no need to install busbars, CCS voltage connectors, or data acquisition components on these sides. Therefore, the busbars, CCS voltage connectors, and data acquisition components in each battery cell 2 can be reduced by half.) Multiple combined batteries are arranged to form a battery module. When the battery module is used in a battery pack, it reduces the space occupied inside the battery pack, reliably ensuring the volumetric energy density of the battery pack.

[0027] Furthermore, in this battery assembly method, end plates 3 are provided on both sides of the cover assembly 1. These end plates 3 support the cover assembly 1 and the electrode groups 22, ensuring the stable fixation of the two electrode groups 22 on opposite sides of the cover assembly 1 within the battery casing 21, thereby guaranteeing the reliability and safety of the battery assembly. Even further, a single-end plate 24 is provided on the side of the electrode group 22 furthest from the cover assembly 1, further ensuring the stable fixation of the electrode group 22 within the battery casing 21.

[0028] In some embodiments of this application, after step S2, the battery assembly method includes: S3: The electrical connection between the positive electrode tab and the positive electrode connection part 121 is welded, and a protective adhesive tape for the positive electrode soldering is applied at the welding position; the electrical connection between the negative electrode tab and the negative electrode connection part 122 is welded, and a protective adhesive tape for the negative electrode soldering is applied at the welding position.

[0029] It should be noted that the application of protective adhesive tape for the positive electrode and the negative electrode can be performed sequentially or in reverse order, or simultaneously; preferably, they can be performed simultaneously, which can optimize the process flow and ensure assembly efficiency.

[0030] By applying protective tape to the positive electrode solder joint, the solder marks formed when the positive electrode tab is soldered at the positive electrode connection 121 can be covered, preventing solder slag from falling into the electrode assembly 22 and causing an internal short circuit. Similarly, by applying protective tape to the negative electrode solder joint, the solder marks formed when the negative electrode tab is soldered at the negative electrode connection 122 can be covered, preventing solder slag from falling into the electrode assembly 22 and causing an internal short circuit.

[0031] In some embodiments of this application, the electrode group 22 includes a plurality of sides perpendicular to the cover plate assembly 1; step A1 is included before step S2; A1: in both electrode groups, the sides of each electrode group 22 are covered with a Mylar film 25.

[0032] It should be noted that the order of steps A1 and S1 can be interchanged.

[0033] Step A1 achieves the coating of the electrode assembly 22 by the Mylar film 25, thereby ensuring the insulation and isolation effect between the electrode assembly 22 and the battery casing 21, and preventing the occurrence of internal short circuits in the battery. In addition, the Mylar film 25 also provides a safety protection effect for the electrode assembly 22, preventing burrs on the battery casing 21 from penetrating the separator of the electrode assembly 22 and causing internal short circuits in the battery, thus ensuring the safety and reliability of the combined battery.

[0034] In some embodiments of this application, in step A1, a side plate 26 is provided on at least one side. The side plate 26 is first thermally fused with the Mylar film 25 to form an inner insulation assembly, and then the inner insulation assembly is wrapped around multiple sides of the electrode assembly 22.

[0035] It should be noted that the dimensions of the side plate 26 are adapted to the dimensions of its opposite side. Before covering the Mylar film 25, the side plate 26 is heat-fused onto the Mylar film 25. This allows the side plate 26 to cover the sides of the electrode assembly 22 when the inner insulating component is wrapped around it. This protects the sides of the electrode assembly 22 during installation, preventing scratches. Furthermore, the side plate 26 provides support and fixation for the electrode assembly 22 within the battery casing 21, further preventing misalignment and movement during use, thus ensuring the reliability and safety of the battery pack.

[0036] In some embodiments of this application, step A2 is included after step S2. A2: In the two electrode groups 22, on the side closer to the cover plate assembly 1, the Mylar film 25 of each electrode group 22 is thermally bonded to the end plate 3 on the opposite side.

[0037] It should be noted that, on the side away from the cover plate assembly 1, the Mylar membrane 25 of the electrode group 22 is thermally fused to the single end plate 24 on the opposite side.

[0038] As described above, along the direction from the cover assembly 1 to the single-end plate 24 (parallel to the direction from the positive to the negative electrode of the battery cell 2), the two ends of the Mylar film 25 are respectively thermally fused to the end plate 3 and the single-end plate 24 along the circumference of the electrode assembly 22. This avoids direct contact between the electrode assembly 22 and the metal cover body, preventing internal short circuits caused by assembly errors, vibration, or expansion, thus ensuring the sealing, safety, and reliability of the battery pack.

[0039] In some embodiments of this application, housing assembly portions are formed at opposite ends of the cover plate assembly 1, respectively, arranged circumferentially thereon; after step S3, the battery assembly method includes: S4: Select two battery housings 21 with the first opening and the second opening facing each other; assemble the two battery housings 21 one-to-one to the outside of the two pole groups 22, and make the first opening opposite to the housing assembly part; S5: Fix the two first openings of the two battery housings 21 to the two housing assembly parts respectively.

[0040] As shown above, the assembly of the battery casing 21 is achieved. The steps of assembling the two battery casings 21 can be performed sequentially or in reverse order, or simultaneously; preferably, they can be performed simultaneously, which can optimize the process flow and ensure assembly efficiency.

[0041] In some embodiments of this application, step A3 is included before step S4; A3: the two pole groups 22 are unfolded in a side-by-side arrangement direction.

[0042] It should be noted that the parallel arrangement direction is parallel to the direction from the positive electrode to the negative electrode of the battery cell 2. When the two electrode groups 22 are arranged in a parallel direction, that is, the two battery cells 2 are located on the same straight line from the positive electrode to the negative electrode.

[0043] As described above, this ensures the smooth and reliable insertion of electrode assembly 22 into the casing, avoids collision damage to electrode assembly 22 during the insertion process, prevents deformation of electrode assembly 22, ensures insertion efficiency, improves insertion success rate, and at the same time ensures the safety and reliability of the combined battery.

[0044] In some embodiments of this application, the housing assembly is formed with a stepped surface a, the end of the enclosure of the first opening abuts against the stepped surface a, and welding is performed on the outer periphery of the abutment.

[0045] As mentioned above, the stepped surface a of the housing assembly part can provide precise positioning for the assembly and fixation of the battery housing 21 on the cover plate assembly 1, improving the accuracy, consistency and efficiency of production assembly; the stepped surface a of the housing assembly part and the end face of the first opening of the battery housing 21 can be sealed and abutted with zero gap, thereby ensuring the reliable sealing assembly effect of the battery housing 21 on the cover plate assembly 1 and improving the sealing reliability; when the stepped surface a and the wall of the first opening are fixed by laser welding, the welding energy can be applied evenly and efficiently to the joint between the two, and the molten metal can be well fused together to form a welded joint with a reasonable depth-to-width ratio, uniform continuity, few pores and high strength.

[0046] In some embodiments of this application, after step S5, the battery assembly method includes: S6: Select two single-pole cover plates 23 with opposite polarities, select a single-pole cover plate 23 with the same polarity as the tab at the second opening of the pole group 22, and electrically connect the single-pole cover plate 23 to the tab on its opposite side. S7: Fix the two second openings of the two battery casings 21 to the two single-pole cover plates 23 respectively.

[0047] As described above, the assembly of the single-pole cover 23 at the second opening of the battery casing 21 and the electrical connection of the electrode tab at the single-pole cover 23 are achieved, thereby realizing the output of electrical energy. The two single-pole covers 23 mentioned above have opposite polarities, one is the positive electrode and the other is the negative electrode.

[0048] In some embodiments of this application, the fixed connection between the first opening of the battery housing 21 and the housing assembly includes pre-spot welding and full welding. Pre-welding ensures the accurate positioning of the housing assembly at the first opening of the battery housing 21 and the convenience and reliability of the subsequent full welding operation; full welding after pre-welding ensures a firm fixation between the housing assembly and the wall of the first opening, preventing the cover assembly 1 from falling off during use and ensuring the safety and reliability of the combined battery.

[0049] In some other embodiments, the fixed connection between the second opening of the battery casing 21 and the single-pole cover plate 23 includes pre-spot welding and full welding. Pre-welding ensures the precise positioning of the single-pole cover plate 23 at the second opening of the battery casing 21 and ensures the convenience and reliability of the subsequent full welding operation; pre-welding followed by full welding ensures a secure fixation between the single-pole cover plate 23 and the wall of the second opening, preventing the single-pole cover plate 23 from falling off during use and ensuring the safety and reliability of the combined battery.

[0050] In some embodiments of this application, the assembly method of the pole group 22 includes: G1: Stack the positive electrode, separator, and negative electrode in sequence; G2: Pre-solder the positive electrode tab and the negative electrode tab; G3: Apply positive electrode tab tape to the pre-welded position of the positive electrode tab; apply negative electrode tab tape to the pre-welded position of the negative electrode tab.

[0051] As described above, pre-welding multiple layers of positive electrode tabs together prevents them from becoming loose or misaligned, ensuring that the positive electrode tab bundle will not separate, fold, or misalign during subsequent transport, positioning, and main welding with cover plate assembly 1 or single-pole cover plate 23, thus guaranteeing welding quality. Similarly, pre-welding multiple layers of negative electrode tabs together prevents them from becoming loose or misaligned, ensuring that the negative electrode tab bundle will not separate, fold, or misalign during subsequent transport, positioning, and main welding with cover plate assembly 1 or single-pole cover plate 23, thus guaranteeing welding quality. Furthermore, applying adhesive tape to the positive electrode tabs ensures a cohesive effect, further guaranteeing welding quality during the main welding process with cover plate assembly 1 or single-pole cover plate 23. Similarly, applying adhesive tape to the negative electrode tabs ensures a cohesive effect, further guaranteeing welding quality during the main welding process with single-pole cover plate 23 or cover plate assembly 1.

[0052] In some embodiments of this application, the cover plate assembly 1 includes two cover plate units 11 disposed opposite to each other, and a pole post connecting portion 12 that fixes the two cover plate units 11 together; each cover plate unit 11 has a housing assembly portion formed on its outer periphery.

[0053] It should be noted that the cover plate unit 11 includes a cover plate body and insulating components disposed on opposite sides of the cover plate body, as well as sealing components and other structures; the housing assembly part is disposed on the cover plate body.

[0054] As described above, the cover assembly 1, which is configured with two cover units 11, can ensure that each cover unit 11 independently and reliably seals the battery casing 21 opposite to it, ensuring the sealing reliability inside each battery cell 2, as well as ensuring assembly strength, and ensuring the reliability and safety of the combined battery.

[0055] In some other embodiments, the cover assembly may be configured in other ways besides including two cover units 11; for example, the cover assembly may include only one cover unit 11, and the two housing assembly parts on opposite sides of the cover unit 11 may be an integral connection structure located at or near the middle position of the cover unit 11 along its thickness direction; both sides of the aforementioned integral connection structure along the thickness direction of the cover assembly are stepped surfaces a, for abutting and engaging with the end of the enclosure of the first opening of the battery housing 21 opposite to the position of the stepped surface a.

[0056] In some parallel embodiments, in a cover assembly 1 having only one cover unit 11, the two housing assembly portions on opposite sides of the cover unit 11 can be spaced a certain distance apart along the thickness direction of the cover assembly.

[0057] Please see Figure 2 In some embodiments of this application, the electrode connection portion 12 includes a positive electrode connection portion 121 and a negative electrode connection portion 122 respectively disposed in the cover plate unit 11. The positive electrode connection portion 121 and the negative electrode connection portion 122 are integrally connected.

[0058] As shown above, the positive electrode connection 121 and the negative electrode connection 122 are set as an integral connection structure, which is simple and compact, reduces the number of parts and assembly steps; and improves the overall mechanical strength and structural stability of the electrode connection 12, preventing loosening or fatigue fracture due to vibration during use.

[0059] Please see Figure 3 In some parallel embodiments, the positive electrode connection 121 and the negative electrode connection 122 are fixed and electrically connected separate connection structures.

[0060] It should be noted that in some embodiments, the two ends of the positive electrode connection 121 and the negative electrode connection 122 that are close to each other are provided with a threaded groove on one end and a threaded post on the other end; the positive electrode connection 121 and the negative electrode connection 122 are fixed and electrically connected by the threaded engagement of the threaded post and the threaded groove.

[0061] Please see Figure 3 In some parallel embodiments, the two ends of the positive electrode connection 121 and the negative electrode connection 122 that are close to each other are formed with insertion grooves; the cover plate assembly 1 also includes a first electrical connector, which is a columnar structure; by the two ends of the first electrical connector respectively engaging with the two insertion grooves, the positive electrode connection 121 and the negative electrode connection 122 are fixed and electrically connected.

[0062] In some other parallel embodiments, the two ends of the positive electrode connection 121 and the negative electrode connection 122 that are close to each other are formed with plug-in posts; the cover plate assembly 1 also includes a second electrical connector, which is a connecting sleeve structure; the second electrical connector is respectively sleeved on the outer periphery of the two plug-in posts to achieve the fixation and electrical connection of the positive electrode connection 121 and the negative electrode connection 122.

[0063] As described above, the various separate connection structures of the positive electrode connection part 121 and the negative electrode connection part 122 are all simple in structure, easy to manufacture, and easy to assemble. They also greatly enrich the connection and fixing methods of the positive electrode connection part 121 and the negative electrode connection part 122, allowing users to choose according to their needs, offering strong flexibility and applicability. Furthermore, the detachable connection of the positive electrode connection part 121 and the negative electrode connection part 122 facilitates disassembly, replacement, and maintenance.

[0064] Please see Figure 2 In some embodiments of this application, along the thickness direction of the cover plate assembly: the thickness of the cover plate unit 11 is T; the thickness of the mating connection is B; 0.4mm≤B≤0.5T.

[0065] As mentioned above, the thickness of the mating connection is limited to a suitable range, avoiding the disadvantages of insufficient welding strength between the thickness B and the battery casing 21 due to excessively thin thickness, resulting in defects such as cracks and molten beads; at the same time, it avoids the disadvantage of excessively thick thickness B, resulting in a large weight of the combined battery.

[0066] Please see Figure 2 In some embodiments of this application, the wall thickness of the battery housing 21 is A along the radial direction of the cover assembly; 0.25mm≤A≤0.8B. As shown above, the wall thickness of the battery casing 21 is limited to a suitable range, avoiding the disadvantages of insufficient welding strength and defects such as cracks and molten beads caused by excessively thin thickness A and insufficient welding strength of the mating connection part; at the same time, it avoids the disadvantages of excessively thick thickness A, which would result in a large weight of the battery casing 21 and affect the volumetric energy density of the combined battery.

[0067] In summary, this application also provides a combined battery, which is assembled by the combined battery assembly method described above.

[0068] Since the combined battery of this application is assembled by the above-described combined battery assembly method, the beneficial effects of the combined battery brought by the above-described battery assembly method can be found above, and will not be repeated here. In summary, this application also provides a battery module comprising a plurality of combined batteries as described above, arranged at intervals along the thickness direction of the battery cells.

[0069] Since the battery module of this application includes the combined battery described above, and the combined battery includes the cover assembly described above, the beneficial effects of the cover assembly on the battery module are described above and will not be repeated here.

[0070] In summary, this application also provides a battery pack, which includes a base frame and battery modules as described above mounted on the base frame. The battery module of this application includes two sub-cell modules, with no crossbeams or longitudinal beams between the two sub-cell modules. Furthermore, the sides of the two adjacent cells within the two sub-cell modules no longer have busbars, CCS voltage connections, or data acquisition devices, resulting in a smaller footprint and ensuring higher battery volumetric energy density.

[0071] The block diagrams of devices, apparatuses, devices, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0072] It should also be noted that in the apparatus, equipment, and methods of this application, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered as equivalent solutions of this application.

[0073] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0074] It should be understood that the qualifiers “first,” “second,” “third,” “fourth,” “fifth,” and “sixth” used in the description of the embodiments of this application are only used to more clearly illustrate the technical solutions and are not intended to limit the scope of protection of this application.

[0075] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A method for assembling a combined battery, characterized in that, The method achieves the fixed sealing and electrical connection of two battery cells with opposite first openings in the battery casing via a cover plate assembly, wherein end plates are provided on both opposite sides of the cover plate assembly; the combined battery assembly method includes: S1: Select two pole groups with positive and negative electrodes arranged opposite each other; each pole group is equipped with an end plate and a single end plate at both ends, and the positive electrode extends out to the end plate or the single end plate opposite to it, and the negative electrode extends out to the single cover plate or the end plate opposite to it. S2: Select the cover plate assembly with positive and negative electrode connections respectively on opposite sides; electrically connect the positive electrode tab of one of the electrode groups to the positive electrode connection of the cover plate assembly, and electrically connect the negative electrode tab of the other electrode group to the negative electrode connection of the cover plate assembly.

2. The battery assembly method according to claim 1, characterized in that, After step S2, the combined battery assembly method includes: S3: The electrical connection between the positive electrode tab and the positive electrode connection part is welding, and protective adhesive tape for positive electrode welding is applied at the welding position; the electrical connection between the negative electrode tab and the negative electrode connection part is welding, and protective adhesive tape for negative electrode welding is applied at the welding position. And / or, The electrode group includes multiple sides perpendicular to the cover plate assembly; step A1 is included before step S2; A1: In the two electrode groups, each side of the electrode group is covered with a Mylar film.

3. The battery assembly method according to claim 2, characterized in that, In step A1, at least one side is provided with a side plate. The side plate is first thermally fused with the Mylar film to form an inner insulation component, and then the inner insulation component is wrapped around the side. And / or, Step S2 is followed by step A2; A2: In the two electrode groups, the Mylar film of each electrode group is thermally fused to the end plate on the opposite side thereto; And / or, The order of steps S1 and A1 is not limited.

4. The battery assembly method according to claim 1, characterized in that, The cover plate assembly has housing assembly portions formed at opposite ends, arranged circumferentially thereon; after step S3, the combined battery assembly method includes: S4: Select two battery casings with the first opening and the second opening facing each other; assemble the two battery casings one-to-one onto the outside of the two electrode groups, and make the first opening opposite to the casing assembly part; S5: Fix the two first openings of the two battery casings to the two casing assembly parts respectively.

5. The combined battery assembly method according to claim 4, characterized in that, Before step S4, the combined battery assembly method includes step A3; A3: unfolding the two electrode groups in a side-by-side arrangement direction; And / or, The housing assembly has a stepped surface, and the end of the enclosure of the first opening abuts against the stepped surface and is welded to the outer periphery where the two abut.

6. The combined battery assembly method according to claim 4, characterized in that, After step S5, the combined battery assembly method includes: S6: Select two single-pole cover plates with opposite polarities, select a single-pole cover plate with the same polarity as the tab at the second opening of the pole group, and electrically connect the single-pole cover plate to the tab on its opposite side. S7: Fix the two second openings of the two battery casings to the two single-pole cover plates respectively.

7. The battery assembly method according to claim 6, characterized in that, The fixed connection between the first opening and the housing assembly includes pre-spot welding and full welding; The fixed connection between the second opening and the single-pole cover plate includes pre-spot welding and full welding.

8. The method for assembling a combined battery according to claim 1, characterized in that, The assembly method of the pole group includes: G1: Stack the positive electrode, separator, and negative electrode in sequence; G2: Pre-solder the positive electrode tab and the negative electrode tab; G3: Apply positive electrode tab tape to the position where the positive electrode tab is pre-welded; apply negative electrode tab tape to the position where the negative electrode tab is pre-welded.

9. The method for assembling a combined battery according to any one of claims 1-8, characterized in that, The cover plate assembly includes two cover plate units; the positive electrode connection part and the negative electrode connection part are an integral structure or an electrically connected separate structure, the positive electrode connection part and the negative electrode connection part are respectively passed through the two cover plate units, and the two cover plate units are fixed. or, The cover plate assembly includes a cover plate unit; the positive electrode connection part and the negative electrode connection part are an integral structure or electrically connected separate structures, and the positive electrode connection part and the negative electrode connection part pass through the cover plate unit.

10. A combined battery, characterized in that, It is assembled by the combined battery assembly method as described in any one of claims 1-9.

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