Battery cell

Abstract

To provide a battery cell that assembles a module without using a laser welder, and can be reused as a reusable module.SOLUTION: A battery cell according to an embodiment includes a housing in which an electrode terminal portion is formed, a resin cap member fitted to the housing, a first electrode bus bar partially supported by the cap member and welded to the electrode terminal portion, and a threaded member whose base is fitted in a recess formed in the cap member with its rotation restricted, and whose threaded portion protrudes through an opening formed in the first electrode bus bar.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] FIELD OF THE INVENTION An embodiment of the present invention relates to a battery cell. [Background technology]

[0002] 2. Description of the Related Art Conventionally, secondary batteries that use lithium titanate (LTO) as the negative electrode have been known. In this secondary battery, the negative electrode is lithium titanate (LTO), so the cell terminal is made of aluminum. Because aluminum is soft, if it is used with a threaded structure like a bolt, it cannot withstand the torque applied when fastened.

[0003] For this reason, aluminum was also used for the bus bars between cells, and the terminals and aluminum bus bars were joined by laser welding.

[0004] On the other hand, in conventional technology, the cell terminals are often threaded, and the inter-cell bus bars are typically fitted into the threads and fastened with nuts. In this case, the structure of the cap body at the top of the cell is manufactured with screw fastening in mind, so that excessive force is not applied to the bus bars or terminal crimping parts when the screws are fastened. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-283256 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-283335 [Patent Document 3] Japanese Patent Application Laid-Open No. 2009-301874 [Patent Document 4] Japanese Patent Application Laid-Open No. 2014-026948 Summary of the Invention [Problem to be solved by the invention]

[0006] In contrast, the cell terminals of secondary batteries that use lithium titanate (LTO) for the negative electrode only have aluminum protrusions, and the busbars are fastened by welding. Therefore, there was no choice but to use aluminum for the bus bars connecting the cells, which can be welded to aluminum terminals. Aluminum is inferior to copper in terms of strength and electrical resistance, which is a disadvantage.

[0007] In addition, the inter-cell bus bars are joined by laser welding after the module in which the cells are arranged is fabricated, but this has disadvantages in module fabrication, such as the need for large-scale laser welding equipment and the time required for welding when the module is made up of a large number of cells.

[0008] Furthermore, when reusing cells after a certain period of use, it is desirable to select cells with the same degree of deterioration and reassemble the module. However, the current method of directly welding the cell terminals and the bus bars between the cells makes it difficult to disassemble the cells individually, making reuse difficult and undesirable from the perspective of efficient resource utilization.

[0009] The present invention has been made in view of the above, For joining bus bars between cells when assembling battery modules The object is to provide a battery cell that can be assembled into a module without the need for a laser welder, and that can also be reused as a reuse module. [Means for solving the problem]

[0010] The battery cell of the embodiment includes a housing in which an electrode terminal portion is formed, When the connector is fitted to the housing, the connector has a fitting recess that contacts the peripheral surface of the housing and a plurality of protrusions for preventing the connector from lifting up, a resin cap member fitted to the housing; The lift-preventing projections have a plurality of openings through which the lift-preventing projections are inserted, and the tips of the lift-preventing projections are plastically deformed and crimped in a state where they are inserted into the openings. A portion of the cap member is supported by the cap member. The aforementioned The cap member includes a first electrode bus bar joined to an electrode terminal portion by welding, and a screw member whose base is fitted into a recess formed in the cap member in a state where rotation is restricted, and whose screw portion protrudes through an opening formed in the first electrode bus bar. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is an external view of a battery cell according to a first embodiment, showing three views. [Figure 2] FIG. 2 is a plan view of the cap member. [Figure 3] FIG. 3 is a cross-sectional view taken along the line AA in FIG. [Figure 4] FIG. 4 is an explanatory diagram of the anti-floating projection in use. [Figure 5] FIG. 5 is a front view of the battery module of the first embodiment. [Figure 6] FIG. 6 is an external view of a battery cell according to the second embodiment from three angles. [Figure 7] FIG. 7 is an explanatory diagram of a cap member according to the second embodiment. [Figure 8] 8 is a cross-sectional view taken along the line BB in FIG. [Figure 9] FIG. 9 is a front view of the battery module of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] [1] First embodiment FIG. 1 is an external view of a battery cell according to a first embodiment, showing three views. Here, FIG. 1(A) is a plan view, FIG. 1(B) is a front view, and FIG. 1(C) is a side view. As shown in FIG. 1(B), the battery cell 10 of the first embodiment includes a housing 11 and a cap member 12 fitted into the upper end of the housing 11 (upward in FIG. 1).

[0013] Housing 11 has a vertically long box shape, and flat plate-shaped electrode terminals 15A and 15B are provided on the top surface of housing 11. Screw members 14A and 14B protrude from the top surfaces of electrode terminals 15A and 15B via electrode bus bars 16A and 16B.

[0014] In this case, electrode terminals 15A and 15B form electrode terminal portions, and electrode bus bars 16A and 16B function as first electrode bus bars. Moreover, from the viewpoint of cost and strength, hexagonal bolts made of iron or stainless steel are used as the screw members 14A and 14B. As a result, it can withstand the tightening torque of a standard screw and can be easily disassembled and reassembled.

[0015] A rupture opening 25, which will be described later, is provided in the center of the cap member 12 at a position corresponding to the rupture 17 provided on the top surface of the housing 11. This rupture opening 25 is provided so as not to hinder the operation of the rupture 17. Here, the operation of the rupture 17 refers to the operation of opening the rupture 17 and releasing the internal gas when the internal pressure of the housing 11 due to gas generated inside the housing 11 exceeds a predetermined value.

[0016] Additionally, a code sticker 18 is attached to the surface of the cap member 12 near the rupture opening 25, on which a two-dimensional code containing information corresponding to the type of battery cell 10 is printed. This code sticker 18 is used to identify the correct battery cell when multiple battery cells 10 are used to configure a battery pack (battery cell unit), and to accurately identify the battery type when reusing battery cells.

[0017] FIG. 2 is a plan view of the cap member. FIG. 2A is a plan view of the cap member 12. FIG. FIG. 2B is a cross-sectional view taken along the line BB in FIG. 2A. The cap member 12 includes a frame member 21, a base portion 22, an opening 23 for an electrode terminal, a recess 24 for a screw member base, an opening 25 for rupture, a protrusion 26 for preventing lifting, and a protrusion 27 for preventing rotation.

[0018] The frame member 21 is formed to surround the periphery of the base portion 22, and cooperates with the base portion 22 on the underside of the cap member 12 to form a fitting recess 29 that is fitted into the upper end of the housing 11 of the battery cell 10 and restricts the rotation of the cap member 12.

[0019] A recess 24 for a screw member base is formed in the base portion 22. Furthermore, a plurality of (in the example of FIG. 2, 4 pieces × 2 locations = 8 pieces) lift-up prevention protrusions 26 and a plurality of (in the example of FIG. 2, 2 pieces × 2 locations = 4 pieces) rotation prevention protrusions 27 are protruded from the upper surface of the base portion 22. Furthermore, the base portion 22 is provided with electrode busbar recesses 28 for holding and supporting the electrode busbars 16A, 16B.

[0020] The electrode terminal openings 23 have a rectangular shape in plan view, and are formed in positions that expose the electrode terminals 15A, 15B on the top surface of the battery cell 10 when the cap member 12 is fitted.

[0021] FIG. 3 is a cross-sectional view taken along the line AA in FIG. The screw member base recess 24 is configured to have the same shape as the outer shape (for example, a polygonal shape in plan view; in FIG. 2, a hexagon) of the bases 14A1, 14B1 (see FIG. 3) of the screw members 14A, 14B in plan view.

[0022] When the nuts corresponding to the screw members 14A and 14B are tightened, the inner peripheral surface of the recess 24 for the screw member base abuts against the peripheral surfaces of the bases 14A1 and 14B1 of the screw members 14A and 14B, thereby absorbing the rotational torque and restricting the rotation of the screw members 14A and 14B, thereby holding them in a predetermined position.

[0023] Rupture opening 25 has a rectangular shape in a plan view, and is provided so as not to hinder the operation of rupture 17. Here, the operation of rupture 17 refers to the operation of opening and releasing the internal gas when the internal pressure of casing 11 due to gas generated inside casing 11 exceeds a predetermined value.

[0024] FIG. 4 is an explanatory diagram of the anti-floating projection in use. A plurality of anti-lifting protrusions 26 are provided around the periphery of the recess 24 for the screw member base, and are inserted into the same number of openings provided in the electrode bus bars 16A, 16B, respectively, with their tips crushed and crimped in a heated state, thereby preventing the electrode bus bars 16A, 16B from lifting up.

[0025] The anti-rotation protrusions 27 are arranged at positions spaced a predetermined distance apart from the axes of the threaded portions 14A2 and 14B2 of the screw members 14A and 14B, and when inserted into the same number of openings provided in the electrode bus bars 16A and 16B, respectively, they restrict the rotation of the electrode bus bars 16A and 16B.

[0026] In the above configuration, electrode bus bars 16A, 16B have a shape in which a flat metal plate is bent into a substantially S-shaped cross section, as shown in the cross section of FIG. 3, that is, a shape in which both end flat plate portions are connected by a bent portion.

[0027] For this reason, the electrode busbar recess 28 is provided with a first support surface portion 28A that supports the flat plate portion at one end of the electrode busbar 16A or the electrode busbar 16B from the underside, and a second support surface portion 28B that is formed at a level with the first support surface portion and supports the flat plate portion at the other end of the electrode busbar 16A or the electrode busbar 16B from the underside.

[0028] Furthermore, on the electrode terminal 15A side of the electrode bus bar 16A, there is a circular opening that follows the outer peripheral shape of the cylindrical protrusion 15A1 provided in the center of the electrode terminal 15A, and there is also a welding recess 16A1 that reduces the thickness of the electrode bus bar 16A for welding. Further, on the rupture 17 side of the electrode bus bar 16A, there is provided a screw member opening 16A2 into which the threaded portion of the screw member 14A is inserted.

[0029] Similarly, the electrode bus bar 16B has a circular opening on the electrode terminal 15B side that conforms to the outer peripheral shape of the cylindrical protrusion 15B1 provided in the center of the electrode terminal 15B, and also has a welding recess 16B1 that reduces the thickness of the electrode bus bar 16B for welding. Furthermore, on the rupture 17 side of the electrode bus bar 16B, a screw member opening 16B2 into which the threaded portion 14B2 of the screw member 14B is inserted is provided.

[0030] In the above configuration, if the welding conditions or welding specifications allow, it is not necessary to provide the welding recesses 16A1 and 16B1, and they can be formed from a metal plate having a uniform thickness.

[0031] Similarly, if cylindrical projections 15A1, 15B1 of electrode terminals 15A, 15B are not provided, openings in electrode bus bars 16A, 16B provided to correspond to projections 15A1, 15B1 do not need to be provided.

[0032] Here, a method for assembling the battery cell 10 will be described. First, the cap member 12 is fitted onto the upper end of the housing 11 . Next, the screw members 14A and 14B are prepared and fitted into the pair of recesses 24 for screw member bases of the cap member 12, respectively.

[0033] Then, electrode bus bars 16A and 16B are prepared, and threaded portion 14A2 of screw member 14A is inserted into screw member opening 16A2 of electrode bus bar 16A, and threaded portion 14B2 of screw member 14B is inserted into screw member opening 16B2 of electrode bus bar 16B. At the same time as inserting the threaded portions 14A2 and 14B2, the lift-up prevention projections 26 and the rotation prevention projections 27 are inserted into the openings of the electrode bus bars 16A and 16B, respectively.

[0034] Then, the circular opening of the welding recess 16A1 of the electrode bus bar 16A is fitted into the cylindrical protrusion 15A1 provided in the center of the electrode terminal 15A, and the circular opening of the welding recess 16B1 of the electrode bus bar 16B is fitted into the cylindrical protrusion 15B1 provided in the center of the electrode terminal 15B.

[0035] In this state, welding is performed to mechanically and electrically connect electrode bus bar 16A to electrode terminal 15A. Similarly, welding is performed to mechanically and electrically connect electrode bus bar 16B to electrode terminal 15B.

[0036] Furthermore, the tips of anti-lift projections 26 are heated, crushed and plastically deformed to be crimped, thereby preventing electrode bus bars 16A, 16B from lifting up due to the movement of screw members 14A, 14B, and the assembly is completed. As a result, it is possible to assemble a battery module without using a laser welder, and it is possible to obtain battery cells 10 that can be reused as a reuse module.

[0037] Next, the assembly of the battery module will be described. FIG. 5 is a front view of the battery module of the first embodiment. In the following description, it is assumed that the screw members 14A and 14B have different polarities, and that the screw members 14A and 14B have the same polarity (one is positive and the other is negative).

[0038] The battery module 100 includes a plurality of battery cells 10 (10-1 to 10-4). An inter-cell bus bar 101-1 is inserted between the screw member 14B of the battery cell 10-1 and the screw member 14A of the battery cell 10-2.

[0039] Furthermore, nut 102-1 is screwed onto screw member 14B of battery cell 10-1 to secure inter-cell bus bar 101-1. Similarly, nut 102-2 is screwed onto screw member 14A of battery cell 10-2 to secure inter-cell bus bar 101-1.

[0040] Similarly, a nut is screwed into screw member 14B (not shown) of battery cell 10-2 to secure inter-cell bus bar 101-2. Similarly, a nut is screwed into screw member 14A of battery cell 10-3 to secure inter-cell bus bar 101-2.

[0041] Furthermore, an inter-cell bus bar 101-3 is inserted into the screw member 14B of the battery cell 10-3 and the screw member 14A of the battery cell 10-4, and a nut 102-3 is screwed into the screw member 14B of the battery cell 10-3 to secure the inter-cell bus bar 101-3. Similarly, a nut 102-4 is screwed into the screw member 14A of the battery cell 10-4 to secure the inter-cell bus bar 101-3.

[0042] As a result, the battery cells 10-1 to 10-4 are connected in series. In the same manner, more battery cells 10 can be easily connected to form a battery module 100. Although the above description has been given for the case of a series connection, it is possible to configure a battery module 100 having a desired voltage and a desired current capacity by appropriately connecting the batteries in parallel.

[0043] As explained above, according to the first embodiment, screw members are electrically and mechanically connected to electrode bus bars (first electrode bus bars) that are welded to the electrode terminals of the battery cells in advance, with rotation restricted by a resin member. Therefore, when assembling the module, the module can be assembled simply by fastening with fastening members such as nuts, making it possible to assemble the battery module without the need for a laser welder. Furthermore, when disassembling the battery module, the battery cells can be created simply by releasing the fastening members, which allows for easy disassembly, and ultimately provides a terminal structure for a secondary battery and a secondary battery that can be reused as a reusable module.

[0044] [2] Second embodiment Next, a second embodiment will be described. The second embodiment is an embodiment that allows the length of the inter-cell bus bars to be shortened when configuring a battery module, even when the battery cells are arranged in the front width direction.

[0045] FIG. 6 is an external view of a battery cell according to the second embodiment from three angles. Here, FIG. 6(A) is a plan view, FIG. 6(B) is a front view, and FIG. 6(C) is a side view. In FIG. 6, the same parts as those in the first embodiment in FIG. 1 are denoted by the same reference numerals.

[0046] As shown in FIG. 6(B), the battery cell 50 of the second embodiment includes a housing 11 and a cap member 51 fitted into the upper end of the housing 11 (upward in FIG. 1).

[0047] Housing 11 has a vertically long box shape, and first screw members 53A and 53B are provided protruding from the top surface of housing 11 via second electrode bus bars 52A and 52B and a first electrode bus bar described below.

[0048] These first screw members 53A and 53B are fastened to the first electrode bus bar and the second electrode bus bar 52A and 52B by nuts 54A and 54B, respectively. Furthermore, second screw members 55A and 55B are provided to protrude through second electrode bus bars 52A and 52B.

[0049] In this case as well, as in the first embodiment, the first screw members 53A, 53B and the second screw members 55A, 55B are hexagonal bolts made of iron or stainless steel from the viewpoints of cost and strength. As a result, it can withstand the tightening torque of a standard screw and can be easily disassembled and reassembled.

[0050] A rupture opening 25 is provided in the center of the cap member 51 at a position corresponding to the rupture 17 provided on the top surface of the housing 11 .

[0051] Additionally, a code sticker 18 is attached to the end surface of the cap member 51, on which a two-dimensional code containing information corresponding to the type of battery cell 50 is printed.

[0052] FIG. 7 is an explanatory diagram of a cap member according to the second embodiment. FIG. 7A is a plan view of the cap member 51. FIG. FIG. 7B is a cross-sectional view taken along the line BB in FIG. 7A.

[0053] The cap member 51 includes a frame member 61, electrode terminal welding openings 62A, 62B, first screw member base recesses 63A, 63B, second screw member base recesses 64A, 64B, a rupture opening 25, a first lift-up prevention protrusion 65, a second lift-up prevention protrusion 66, bus bar recesses 67A, 67B, bus bar openings 68A, 68B, a first support surface 69, and a second support surface 70.

[0054] The frame member 61 forms the peripheral edge of the cap member 51, and the underside of the cap member 51 is provided with a fitting recess 29 that is fitted into the upper end of the housing 11 of the battery cell 10 and serves to restrict the rotation of the cap member 51.

[0055] 8 is a cross-sectional view taken along the line BB in FIG. The electrode terminal welding openings 62A, 62B are openings for inserting a welding machine when welding the first electrode bus bars 16A, 16B to the electrode terminals 15A, 15B of the housing 11.

[0056] The recesses 63A, 63B for the first screw member base are configured to have the same shape as the outer shape (for example, a polygonal shape in plan view; FIG. 7 shows a hexagon) of the bases 53A1, 53B1 (see FIG. 8) of the first screw members 53A, 53B in plan view.

[0057] When the nuts 54A, 54B corresponding to the first screw members 53A, 53B are tightened, the inner surfaces of the first screw member base recesses 63A, 63B abut against the peripheral surfaces of the bases 53A1, 53B1 of the first screw members 53A, 53B, respectively, thereby absorbing the rotational torque and restricting the rotation of the first screw members 53A, 53B, thereby holding them in a predetermined position.

[0058] The recesses 64A, 64B for the second screw member base are configured to have the same shape as the outer shape (for example, a polygonal shape in plan view; FIG. 7 shows a hexagon) of the bases 55A1, 55B1 (see FIG. 8) of the second screw members 55A, 55B in plan view.

[0059] When the nuts corresponding to the second screw members 55A and 55B are tightened, the inner surfaces of the second screw member base recesses 64A and 64B abut against the peripheral surfaces of the bases 55A1 and 55B1 of the second screw members 55A and 55B, respectively, thereby absorbing the rotational torque and restricting the rotation of the second screw members 55A and 55B, thereby holding them in a predetermined position.

[0060] In the above configuration, first electrode bus bars 16A, 16B and second electrode bus bars 52A, 52B have a shape in which a flat metal plate is bent into a substantially S-shaped cross section, as shown in cross section in Figure 8, i.e., a shape in which the flat plate portions at both ends are connected by bent portions.

[0061] Furthermore, on the electrode terminal 15A side of the first electrode bus bar 16A, there is a circular opening that follows the outer peripheral shape of the cylindrical protrusion 15A1 provided in the center of the electrode terminal 15A, and there is also a welding recess 16A1 that reduces the thickness of the electrode bus bar 16A for welding. Furthermore, on the rupture 17 side of the first electrode bus bar 16A, there is provided a screw member opening 16A2 into which the threaded portion of the first screw member 53A is inserted.

[0062] Furthermore, the first electrode bus bar 16B has a circular opening on the electrode terminal 15B side that conforms to the outer peripheral shape of the cylindrical protrusion 15B1 provided in the center of the electrode terminal 15B, and also has a welding recess 16B1 that reduces the thickness of the electrode bus bar 16B for welding. Furthermore, on the rupture 17 side of the first electrode bus bar 16B, there is provided a screw member opening 16B2 into which the threaded portion 14B2 of the screw member 14B is inserted.

[0063] Similarly, the second electrode bus bar 52A is provided on the first screw member 53A side with a screw member opening 52A1 into which the threaded portion 53A2 of the first screw member 53A is inserted. Further, the second electrode bus bar 52A is provided on the second screw member 55A side with a screw member opening 52A2 into which the threaded portion 55A2 of the second screw member 55A is inserted.

[0064] Further, second electrode bus bar 52B is provided on the first screw member 53B side with a screw member opening 52B1 into which threaded portion 53B2 of first screw member 53B is inserted. Further, the second electrode bus bar 52B is provided on the second screw member 55B side with a screw member opening 52B2 into which the threaded portion 55B2 of the second screw member 55B is inserted.

[0065] The first support surface 69 holds and supports the first electrode bus bars 16A, 16B. Furthermore, a plurality of first lift-up prevention projections 65 (4 projections×2 locations=8 projections in the example of FIG. 7) are provided on the upper surface of the first support surface 69.

[0066] Additionally, the second support surface 70 holds and supports the second electrode bus bars 52A, 52B. Furthermore, a plurality of second lift-up prevention projections 66 (4 projections×2 locations=8 projections in the example of FIG. 7) are provided to protrude from the upper surface of the second support surface .

[0067] Here, a method for assembling the battery cell 50 will be described. First, the first screw members 53A and 53B are prepared and fitted into the pair of screw member base recesses 63A and 63B of the cap member 51, respectively.

[0068] Then, first electrode busbars 16A and 16B are prepared, and the threaded portion 53A2 of the first screw member 53A is inserted into the screw member opening 16A2 of the first electrode busbar 16A, and the threaded portion 53B1 of the first screw member 53B is inserted into the screw member opening 16B2 of the first electrode busbar 16B. At the same time as inserting the screw portions 53A1, 53B1, the first lift-up prevention projections 66 are inserted into the openings of the first electrode bus bars 16A, 16B.

[0069] Then, the cap member 51 is fitted onto the upper end of the housing 11 . Then, the circular opening of the welding recess 16A1 of the first electrode bus bar 16A is fitted into the cylindrical protrusion 15A1 provided in the center of the electrode terminal 15A, and the circular opening of the welding recess 16B1 of the first electrode bus bar 16B is fitted into the cylindrical protrusion 15B1 provided in the center of the electrode terminal 15B.

[0070] In this state, welding is performed to mechanically and electrically connect first electrode bus bar 16A to electrode terminal 15A. Similarly, first electrode bus bar 16B is mechanically and electrically connected to electrode terminal 15B.

[0071] Furthermore, by heating and crushing the tips of the first anti-lifting projections 66, the first electrode bus bars 16A, 16B are prevented from lifting up in conjunction with the movement of the first screw members 53A, 53B.

[0072] In this state, the second screw members 55A and 55B are prepared and fitted into the pair of screw member base recesses 64A and 64B of the cap member 51, respectively. Next, second electrode busbars 52A and 52B are prepared, and the threaded portion 55A2 of the second screw member 55A is inserted into the screw member opening 52A2 of the second electrode busbar 52A, and the threaded portion 55B2 of the second screw member 55B is inserted into the screw member opening 52B2 of the second electrode busbar 52B.

[0073] Nut 54A is then screwed onto threaded portion 55A2 of second screw member 55A, and first electrode bus bar 16A and second electrode bus bar 52A are fastened by nut 54A. Similarly, nuts 54B are screwed onto threaded portions 55B1 of second screw members 55B, and the nuts 54B are used to fasten first electrode bus bar 16B and second electrode bus bar 52B, completing the assembly.

[0074] As a result, it is possible to assemble a battery module without using a laser welder, and it is possible to obtain battery cells 50 that can be reused as a reuse module. Furthermore, as shown in FIG. 8, the second screw members 55A, 55B are closer to the left and right ends of the cap member 51 than the first screw members 53A, 53B. Therefore, even when other battery cells 50 are connected to the left and right sides of a battery cell 50 in the same orientation, it is possible to shorten the inter-cell bus bars between the battery cells 50.

[0075] Next, the assembly of the battery module will be described. FIG. 9 is a front view of the battery module of the second embodiment. In the following description, the second screw members 55A and 55B have different polarities, and the second screw members 55A and 55B have the same polarity (one is positive and the other is negative).

[0076] The battery module 110 includes a plurality of battery cells 50 (50-1 to 50-3). An inter-cell bus bar 111-1 is inserted between the second screw member 55B of the battery cell 50-1 and the screw member 55A of the battery cell 50-2.

[0077] Furthermore, a nut 112-1 is screwed into the second screw member 55B of the battery cell 50-1 to secure the inter-cell bus bar 111-1. Similarly, a nut 112-2 is screwed into the second screw member 55A of the battery cell 50-2 to secure the inter-cell bus bar 111-1.

[0078] Similarly, a nut 112-3 is screwed onto the second screw member 55B of the battery cell 50-2 to secure the inter-cell bus bar 111-2. Similarly, a nut 112-4 is screwed onto the second screw member 55A of the battery cell 50-3 to secure the inter-cell bus bar 111-2.

[0079] As a result, the battery cells 50-1 to 50-4 are connected in series. In the same manner, more battery cells 50 can be easily connected to form a battery module 110.

[0080] Although the above description has been given for the case of a series connection, it is possible to configure a battery module 110 having a desired voltage and a desired current capacity by appropriately connecting the batteries in parallel. As described above, according to the second embodiment, the first electrode bus bar, which is welded to the electrode terminal of the battery cell in advance, is electrically and mechanically connected to the first screw member that is fitted with the resin member while its rotation is restricted, and the second electrode bus bar is then fastened with a fastening member such as a nut with the first screw member inserted into the opening of the second electrode bus bar, and is then electrically and mechanically connected to the second screw member that is fitted with the resin member while its rotation is restricted. Therefore, when assembling the module, the module can be assembled simply by fastening the second screw member with a fastening member such as a nut, making it possible to assemble the battery module without using a laser welder.

[0081] Furthermore, when disassembling the battery module, the battery cells can be formed simply by releasing the fastening member of the second screw member, which allows for easy disassembly, and ultimately provides a terminal structure for a secondary battery and a secondary battery that can be reused as a reusable module.

[0082] Furthermore, according to the second embodiment, as compared to the first embodiment, even when multiple battery cells 50 are connected facing forward as shown in FIG. 9 , the second screw members are provided in positions close to the left and right ends of the battery cells 50, so the inter-cell bus bars can be shortened, and even when a battery module is configured with an increased number of connected battery cells, energy loss can be reduced and heat generation can be suppressed. Therefore, even when constructing a high-power system such as an emergency power supply, operational efficiency can be improved.

[0083] [3] Modifications of the embodiment Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims.

[0084] For example, in the above explanation, general hexagonal bolts are used as the screw members (screw members 14A, 14B, first screw members 53A, 53B, second screw members 55A, 55B) from the viewpoint of cost, but the same can be applied as long as the base has a shape that can withstand rotational torque, such as a polygonal shape (e.g., triangular, rectangular, pentagonal, star-shaped, etc.) or an asymmetrical shape. [Explanation of symbols]

[0085] 10, 50 battery cells 11. Housing 12 Cap member 14A, 14B screw members 14A1, 14B1 base 14A2, 14B2 threaded section 15A, 15B Electrode terminal (electrode terminal part) 15A1, 15B1 protrusion 16A, 16B Electrode busbars (first electrode busbars) 16A1, 16B1 Welding recess 16A2, 16B2 Openings for screw members 17 Rapture 18 Code sticker 21 Frame members 22 Base 23 Opening for electrode terminal 24 Screw member base recess 25 Rupture opening 26 Prevention protrusion 27 Anti-rotation protrusion 28 Electrode bus bar recess 28A 1st support surface part 28B 2nd support surface part 29. Fitting recess 51 Cap member 52A, 52B Second electrode bus bar 52A1, 52B1 Opening for screw member 52A2, 52B2 Opening for screw member 53A, 53B First screw member 53A1, 53B1 base 53A1, 53B2 threaded section 54A, 54B nuts 55A, 55B Second screw member 55A1, 55B2 base 55A2, 55B2 threaded section 61 Frame members 62A Electrode terminal welding opening 63A, 64A Recessed portion for screw base 65 First lift-up prevention protrusion 66 Second anti-lifting protrusion 67A, 67B Busbar recess 68A, 68B Busbar openings 69 1st support surface 70 Second support surface 100, 110 battery module 101-1~101-3 Inter-cell busbar 102-1~102-4 Nut 111-1~111-2 Inter-cell busbar 112-1~112-4 Nut

Claims

1. a housing in which an electrode terminal portion is formed; a resin cap member fitted to the housing, the cap member having a fitting recess that contacts the peripheral surface of the housing when fitted to the housing and a plurality of protrusions for preventing the cap member from floating up; a first electrode bus bar having a plurality of openings through which the anti-lifting projections are inserted, the first electrode bus bar having a tip end that is plastically deformed and crimped while inserted into the openings so that a portion of the anti-lifting projections is supported by the cap member, and the first electrode bus bar is joined to the electrode terminal portion by welding; a screw member having a base fitted into a recess formed in the cap member in a state where rotation is restricted, and a threaded portion protruding through an opening formed in the first electrode bus bar; A battery cell comprising:

2. the cap member has a plurality of anti-rotation projections; the first electrode bus bar has a plurality of openings through which the anti-rotation protrusions are inserted, The anti-rotation protrusion is inserted into the opening. The battery cell according to claim 1 .

3. The screw member fastens the inter-cell bus bar and electrically connects it to other battery cells. The battery cell according to claim 1 or 2.

4. a second electrode bus bar having an opening through which the threaded portion is inserted, the second electrode bus bar being partially supported by the cap member and fastened to the threaded portion by a fastening member; a second screw member having a base fitted into a recess formed in the cap member in a state where rotation is restricted, and a threaded portion protruding through an opening formed in the second electrode bus bar; The battery cell according to claim 1 , comprising:

5. the second electrode bus bar extends from the fastening member side to the electrode terminal portion side; The battery cell according to claim 4 .

6. the second screw member fastens an inter-cell bus bar to electrically connect it to another battery cell; The battery cell according to claim 4 or claim 5.

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