secondary batteries

Abstract

A conductive member (61) having a conductive member opening (61f) is arranged on the electrode body side of the sealing plate (2) via a first insulating member (10). The insertion portion (7b) of the positive terminal (7) is inserted into the third terminal insertion hole (61c) of the conductive member (61) and connected to the conductive member (61). The conductive member opening (61f) of the conductive member (61) is sealed by a deformable plate (62), and the first positive electrode collector (6a) electrically connected to the positive electrode plate is connected to the deformable plate (62). The conductive member (61) has a pressing protrusion (61e) protruding toward the first insulating member (10) at a portion opposite to the first insulating member (10).

Description

[0001] This application is a divisional application of the application with application number "2018800077461", application date January 23, 2018, and invention name "Secondary Battery". Technical Field

[0002] The present invention relates to a secondary battery. Background Art

[0003] Prismatic secondary batteries such as alkaline secondary batteries and non-aqueous electrolyte secondary batteries are used as driving power sources for electric vehicles (EVs) and hybrid electric vehicles (HEVs, PHEVs).

[0004] These prismatic secondary batteries consist of a rectangular, cylindrical, bottomed package with an opening and a sealing plate that seals the opening. The battery case houses an electrode assembly consisting of a positive plate, a negative plate, and a separator, along with an electrolyte. The sealing plate is attached to the positive and negative terminals. The positive terminal is electrically connected to the positive plate via a positive current collector, while the negative terminal is electrically connected to the negative plate via a negative current collector.

[0005] A prismatic secondary battery has been proposed that includes a current interruption mechanism that operates when the pressure in the battery case exceeds a predetermined value due to overcharging or the like, thereby interrupting the current by cutting off the conductive path between the electrode assembly and the terminal (Patent Document 1 below).

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2013-157099 Summary of the Invention

[0009] Problems to be solved by the invention

[0010] Providing a current interruption mechanism in a rectangular secondary battery makes the battery highly reliable against overcharge, etc. However, there is a demand for the development of a rectangular secondary battery with even higher reliability.

[0011] A main object of the present invention is to provide a secondary battery having a more stable operating voltage of a current interrupt mechanism and high reliability.

[0012] Means for solving problems

[0013] A secondary battery according to one embodiment of the present invention comprises: an electrode body including a positive electrode plate and a negative electrode plate; a packaging body having an opening and housing the electrode body; a sealing plate for sealing the opening; a conductive member having an opening on the electrode body side and arranged on the electrode body side of the sealing plate via a first insulating member; a deformable plate for sealing the opening and deforming due to a pressure increase in the packaging body; a current collecting member for electrically connecting the positive electrode plate or the negative electrode plate to the deformable plate; and a terminal for electrically connecting the positive electrode plate or the negative electrode plate to the deformable plate via the current collecting member, the deformable plate, and the conductive member. The positive electrode plate or the negative electrode plate is electrically connected to the positive electrode plate or the negative electrode plate, the terminal is inserted into the terminal mounting hole provided in the sealing plate, the terminal insertion hole provided in the first insulating member, and the terminal is connected to the conductive member, and at least one of the conductive member and the sealing plate has a pressing protrusion protruding toward the first insulating member at a portion opposite to the first insulating member, and the conductive path between the positive electrode plate or the negative electrode plate and the terminal is cut off as the deformable plate deforms.

[0014] Preferably, the terminals are inserted into terminal insertion holes provided in the conductive member constituting the current-interrupting mechanism, and the terminals and the conductive member are connected. This configuration allows for a simpler method to produce a secondary battery with a highly reliable current-interrupting mechanism. However, the inventors have discovered that this secondary battery configuration presents the following issues, leaving room for further improvement.

[0015] In secondary batteries where the terminals and conductive members are not integrated, and the terminals are inserted into the terminal insertion holes of the conductive members and then connected to the conductive members, the following phenomenon may occur. If an abnormality occurs in the secondary battery and a large amount of gas is generated within the electrode body, this gas can move between the sealing plate and the first insulating member, or between the first insulating member and the conductive member, to the vicinity of the connection between the conductive member and the terminal. There is a possibility that the gas leaks between the conductive member and the terminal and into the space formed by the conductive member and the deformable plate. Furthermore, this gas leakage may delay the operation of the current interruption mechanism.

[0016] In a secondary battery according to one embodiment of the present invention, a pressing protrusion is formed on at least one of the conductive member and the sealing plate at a position opposing the first insulating member. This allows the pressing protrusion to more strongly press the first insulating member disposed between the conductive member and the sealing plate, thereby suppressing the migration of gas into the connection between the conductive member and the terminal. This prevents gas present near the electrode assembly from leaking into the space formed by the conductive member and the deformable plate. Consequently, delays in the operation of the current interruption mechanism can be more reliably prevented.

[0017] The method for connecting the terminal to the conductive member is not particularly limited. Preferably, the terminal is inserted into the conductive member and riveted to the conductive member. Furthermore, preferably, the riveted portion of the terminal is welded to the conductive member. Alternatively, the terminal can be inserted into the conductive member and welded to the conductive member.

[0018] Effects of the Invention

[0019] According to the present invention, a highly reliable secondary battery can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a perspective view of a secondary battery according to an embodiment.

[0021] Figure 2 It is along Figure 1 Cross-sectional view along line II-II.

[0022] Figure 3 It is a plan view of a positive electrode plate according to the embodiment.

[0023] Figure 4 It is a plan view of the negative electrode plate according to the embodiment.

[0024] Figure 5 It is a plan view of an electrode body element according to an embodiment.

[0025] Figure 6 It is a perspective view of the positive electrode terminal, the external insulating member, the sealing plate, the first insulating member, and the conductive member.

[0026] Figure 7 This is a bottom view of the sealing plate after all components are installed.

[0027] Figure 8A It is along Figure 7 The cross-sectional view of line VIIIA-VIIIA, Figure 8B It is along Figure 7 The cross-sectional view of line VIIIB-VIIIB, Figure 8C It is along Figure 7 Cross-sectional view of line VIIIC-VIIIC.

[0028] Figure 9 It is a three-dimensional diagram of the deformed plate.

[0029] Figure 10A is a perspective view of the first positive electrode current collector and the second insulating member before assembly. Figure 10B is a perspective view of the assembled first positive electrode current collector and the second insulating member. Figure 10C It is a perspective view of the first positive electrode current collector and the second insulating member after being fixed.

[0030] Figure 11 yes Figure 8A An enlarged view of the vicinity of the connection between the deformed plate and the first positive electrode current collector.

[0031] Figure 12 This is a perspective view of the sealing plate with various components installed.

[0032] Figure 13 This is a cross-sectional view of the vicinity of the negative electrode terminal along the longitudinal direction of the sealing plate.

[0033] Figure 14 It is a diagram showing a method of attaching a tab to a current collecting member.

[0034] Figure 15 This is a perspective view of the sealing plate and the outer cover.

[0035] Figure 16A This is a diagram showing the outer cover before being mounted on the first insulating member and the second insulating member. Figure 16B This is a diagram after the cover is attached to the first insulating member and the second insulating member.

[0036] Figure 17A This is a cross-sectional view of the positive terminal and the vicinity thereof along the long side of the sealing plate after the outer cover is installed. Figure 17B It is a cross-sectional view of the vicinity of the connection portion between the outer cover and the first insulating member, taken along the short side direction of the sealing plate.

[0037] Figure 18 yes Figure 8A An enlarged view of the vicinity of the connection between the positive electrode terminal and the conductive member.

[0038] Figure 19A This is a diagram of a secondary battery according to a modified example before the outer cover is attached to the first insulating member and the second insulating member. Figure 19B This is a diagram showing a secondary battery according to a modified example after the outer cover portion is attached to the first insulating member and the second insulating member.

[0039] Figure 20 It is a cross-sectional view near a current interruption mechanism of a secondary battery according to a modification. DETAILED DESCRIPTION

[0040] Hereinafter, the structure of a rectangular secondary battery 20 as a secondary battery according to an embodiment will be described. Note that the present invention is not limited to the following embodiment.

[0041] Figure 1 It is a perspective view of a rectangular secondary battery 20 . Figure 2 It is along Figure 1 The cross-sectional view of line II-II. Figure 1 as well as Figure 2As shown, a rectangular secondary battery 20 includes a battery case 100 consisting of a rectangular package 1, a bottomed, square tube-shaped package with an opening, and a sealing plate 2 that seals the opening of the rectangular package 1. The rectangular package 1 and sealing plate 2 are each preferably made of metal, for example, aluminum or an aluminum alloy. Within the rectangular package 1, a stacked electrode assembly 3, composed of positive and negative electrode plates stacked with a separator, is housed along with an electrolyte. A resin insulating sheet 14 is disposed between the electrode assembly 3 and the rectangular package 1.

[0042] A positive electrode tab 40 and a negative electrode tab 50 are provided at the end of the electrode body 3 on the sealing plate 2 side. The positive electrode tab 40 is electrically connected to the positive electrode terminal 7 via the second positive electrode collector 6b and the first positive electrode collector 6a. The negative electrode tab 50 is electrically connected to the negative electrode terminal 9 via the second negative electrode collector 8b and the first negative electrode collector 8a. Here, the first positive electrode collector 6a and the second positive electrode collector 6b constitute the positive electrode collector member 6. The first negative electrode collector 8a and the second negative electrode collector 8b constitute the negative electrode collector member 8. Alternatively, the positive electrode collector member 6 can be formed as a single component. Alternatively, the negative electrode collector member 8 can be formed as a single component.

[0043] The positive electrode terminal 7 is fixed to the sealing plate 2 via a resin external insulating member 11. The negative electrode terminal 9 is fixed to the sealing plate 2 via a resin external insulating member 13. The positive electrode terminal 7 is preferably made of metal, more preferably aluminum or an aluminum alloy. The negative electrode terminal 9 is preferably made of metal, more preferably copper or a copper alloy.

[0044] Preferably, a current-blocking mechanism 60 is provided in the conductive path between the positive electrode plate and the positive electrode terminal 7. This current-blocking mechanism 60 is activated when the pressure in the battery case 100 exceeds a predetermined value, thereby blocking the conductive path between the positive electrode plate and the positive electrode terminal 7. Alternatively, a current-blocking mechanism may be provided in the conductive path between the negative electrode plate and the negative electrode terminal 9.

[0045] The sealing plate 2 is provided with a gas release valve 17. When the pressure in the battery case 100 exceeds a predetermined value, the gas release valve 17 ruptures to release the gas in the battery case 100 to the outside of the battery case 100. The operating pressure of the gas release valve 17 is set to a value higher than the operating pressure of the current interrupt mechanism 60.

[0046] The sealing plate 2 is provided with an electrolyte injection hole 15. After the electrolyte is injected into the battery case 100 through the electrolyte injection hole 15, the electrolyte injection hole 15 is sealed with a sealing plug 16. As the sealing plug 16, a blind rivet is preferably used.

[0047] Next, a method for manufacturing the rectangular secondary battery 20 and details of each structure will be described.

[0048] [Production of positive electrode plate]

[0049] A positive electrode slurry is prepared containing lithium nickel cobalt manganese composite oxide as a positive electrode active material, polyvinylidene fluoride (PVdF) as a binder, a carbon material as a conductive agent, and N-methyl-2-pyrrolidone (NMP) as a dispersion medium. The positive electrode slurry is applied to both sides of a rectangular aluminum foil with a thickness of 15 μm as a positive electrode core. Then, the NMP in the positive electrode slurry is removed by drying, and a positive electrode active material mixture layer is formed on the positive electrode core. After that, a compression process is performed to make the positive electrode active material mixture layer have a given thickness. The positive electrode plate thus obtained is cut into a given shape.

[0050] Figure 3 This is a top view of the positive electrode plate 4 made using the above method. Figure 3 As shown in the figure, the positive electrode plate 4 has a main body with positive active material mixture layers 4b formed on both sides of a rectangular positive electrode core 4a. The positive electrode core 4a protrudes from the end of the main body, and the protruding positive electrode core 4a constitutes a positive electrode tab 40. In addition, the positive electrode tab 40 can be as shown in FIG. Figure 3 As shown, this is a portion of the positive electrode core 4a, but another member may be connected to the positive electrode core 4a to form the positive electrode tab 40. Furthermore, preferably, a positive electrode protective layer 4d having a greater resistance than the positive electrode active material mixture layer 4b is provided in the portion of the positive electrode tab 40 adjacent to the positive electrode active material mixture layer 4b.

[0051] [Manufacturing of negative plate]

[0052] A negative electrode slurry containing graphite as a negative electrode active material, styrene butadiene rubber (SBR) as a binder, carboxymethyl cellulose (CMC) as a thickener, and water is prepared. This negative electrode slurry is applied to both sides of a rectangular copper foil with a thickness of 8 μm, which serves as the negative electrode core. The water in the negative electrode slurry is then removed by drying, forming a negative electrode active material mixture layer on the negative core. Subsequently, a compression process is performed to reduce the negative electrode active material mixture layer to a predetermined thickness. The resulting negative electrode plate is cut into a predetermined shape.

[0053] Figure 4 This is a top view of the negative electrode plate 5 made by the above method. Figure 4 As shown in the figure, the negative electrode plate 5 has a main body with negative active material mixture layers 5b formed on both sides of a rectangular negative electrode core 5a. The negative electrode core 5a protrudes from the end of the main body, and the protruding negative electrode core 5a constitutes a negative electrode tab 50. In addition, the negative electrode tab 50 can be as shown in FIG. Figure 4 As shown, the negative electrode tab 50 is a portion of the negative electrode core 5 a , but another member may be connected to the negative electrode core 5 a to serve as the negative electrode tab 50 .

[0054] [Fabrication of electrode elements]

[0055] By the above method, 50 positive electrode plates 4 and 51 negative electrode plates 5 were prepared, and they were stacked with polyolefin square separators interposed therebetween to prepare a stacked electrode element (3a, 3b). Figure 5 As shown, the stacked electrode elements (3a, 3b) are fabricated such that the positive electrode tabs 40 of each positive electrode plate 4 and the negative electrode tabs 50 of each negative electrode plate 5 are stacked on one end. Separators can be placed on both outer surfaces of the electrode elements (3a, 3b) and secured with tape or the like to form a stacked state of the electrode plates and separators. Alternatively, adhesive layers can be provided on the separators to bond the separators to the positive electrode plates 4 and the separators to the negative electrode plates 5, respectively.

[0056] In addition, the separator is preferably the same size as the negative electrode plate 5 or larger than the negative electrode plate 5 when viewed from above. Alternatively, the positive electrode plate 4 may be placed between two separators, and after the separators are heat-fused to their peripheries, the positive electrode plate 4 and the negative electrode plate 5 may be stacked. Alternatively, a long strip of separator may be used each time the electrode element (3a, 3b) is produced, and the positive electrode plate 4 and the negative electrode plate 5 may be stacked while the long strip of separator is zigzag-shaped. Alternatively, a long strip of separator may be used, and the positive electrode plate 4 and the negative electrode plate 5 may be stacked while the long strip of separator is wound.

[0057] [Installation of each component on the sealing plate (positive electrode side)]

[0058] use Figure 2 、 Figure 6 8 , a method of attaching the positive electrode terminal 7 and the first positive electrode current collector 6 a to the sealing plate 2 and a structure near the positive electrode terminal 7 will be described. Figure 6 It is a perspective view of the positive electrode terminal 7 , the external insulating member 11 , the sealing plate 2 , the first insulating member 10 , and the conductive member 61 before assembly.

[0059] Figure 7 2 is a diagram showing the inner surface side of the battery after the sealing plate 2 is installed. Figure 7 The positive electrode tab 40 and the negative electrode tab 50 are not shown in the figure. Figure 8A It is along Figure 7 A cross-sectional view near the positive terminal 7 along line VIIIA-VIIIA in FIG. Figure 8B It is along Figure 7 A cross-sectional view near the positive terminal 7 along line VIIIB-VIIIB in FIG. Figure 8C It is along Figure 7 A cross-sectional view near the positive terminal 7 of the VIIIC-VIIIC line.

[0060] In the sealing plate 2, the external insulating member 11 is positioned on the battery's outer surface near the positive terminal mounting hole 2a, while the first insulating member 10 and the conductive member 61 are positioned on the battery's inner surface near the positive terminal mounting hole 2a. Next, the insertion portion 7b, provided on one side of the flange 7a of the positive terminal 7, is inserted into the first terminal insertion hole 11a of the external insulating member 11, the positive terminal mounting hole 2a of the sealing plate 2, the second terminal insertion hole 10d of the first insulating member 10, and the third terminal insertion hole 61c of the conductive member 61. The tip of the insertion portion 7b is then riveted to the conductive member 61. This secures the positive terminal 7, the external insulating member 11, the sealing plate 2, the first insulating member 10, and the conductive member 61. Furthermore, riveting the insertion portion 7b of the positive terminal 7 forms an expanded portion at the tip of the insertion portion 7b, having an outer diameter larger than the inner diameter of the third terminal insertion hole 61c of the conductive member 61. Preferably, the caulked portion of the insertion portion 7b of the positive electrode terminal 7 and the conductive member 61 are welded by laser welding or the like. In addition, the first insulating member 10 and the external insulating member 11 are preferably each made of resin.

[0061] In addition, if Figure 6 As shown in FIG8 , the first insulating member 10 includes a first insulating member body 10a disposed opposite the sealing plate 2. A pair of first side walls 10b are provided at both ends of the first insulating member body 10a in the longitudinal direction of the sealing plate 2. A pair of second side walls 10c are provided at both ends of the first insulating member body 10a in the transverse direction of the sealing plate 2. A second terminal insertion hole 10d is provided in the first insulating member body 10a. A first connecting portion 10e is provided on the outer surface of the second side wall 10c. The first connecting portion 10e is preferably provided at the center of the second side wall 10c in the longitudinal direction of the sealing plate 2. Furthermore, a second connecting portion 10f is provided on the outer surface of the second side wall 10c. The second connecting portion 10f is preferably provided at the end of the second side wall 10c in the longitudinal direction of the sealing plate 2.

[0062] A first groove 10x is provided on the surface of the first insulating member body 10a facing the sealing plate 2, and a second groove 10y is provided on the surface of the first insulating member body 10a facing the conductive member 61. The second groove 10y is located further outward than the first groove 10x. Recesses 10g are provided at the four corners of the surface of the first insulating member body 10a facing the sealing plate 2.

[0063] like Figure 6As shown in FIG8 , the conductive member 61 includes a conductive member base portion 61a disposed opposite the first insulating member main body portion 10a, and a tubular portion 61b extending from the edge of the conductive member base portion 61a toward the electrode body 3. The cross-sectional shape of the tubular portion 61b parallel to the sealing plate 2 can be circular or square. A flange portion 61d is provided at the end of the tubular portion 61b on the electrode body 3 side. A conductive member opening portion 61f is provided at the end of the tubular portion 61b on the electrode body 3 side. A pressing protrusion 61e is provided on the surface of the conductive member base portion 61a that faces the first insulating member 10. The pressing protrusion 61e presses the first insulating member 10 against the sealing plate 2. The pressing protrusion 61e is preferably formed at or near the edge of the third terminal insertion hole 61c.

[0064] Next, the deformable plate 62 is positioned so as to block the conductive member opening 61f of the conductive member 61, and the periphery of the deformable plate 62 is welded to the conductive member 61 by laser welding or the like. Thus, the conductive member opening 61f of the conductive member 61 is sealed by the deformable plate 62. The conductive member 61 and the deformable plate 62 are each preferably made of metal, more preferably aluminum or an aluminum alloy.

[0065] Figure 9 : is a perspective view of the deformable plate 62. Figure 9 The upper middle part is the electrode body 3 side, and the lower part is the sealing plate 2 side. Figure 9 As shown, a stepped protrusion 62a is provided at the center of the deformable plate 62, protruding toward the electrode body 3. This stepped protrusion 62a includes a first protrusion 62a1 and a second protrusion 62a2, which has a smaller outer diameter than the first protrusion 62a1 and protrudes from the first protrusion 62a1 toward the electrode body 3. The deformable plate 62 has an annular rib 62b on its outer periphery, protruding toward the electrode body 3. An annular thin-walled portion 62c is provided on the surface of the deformable plate 62 facing the electrode body 3. The deformable plate 62 may be of any shape that can seal the conductive member opening 61f of the conductive member 61.

[0066] Next, a method for fixing the second insulating member 63 and the first positive electrode current collector 6a will be described using Figure 10. In Figure 10, the surface of the prismatic secondary battery 20 disposed on the electrode body 3 side is located at the top, and the surface disposed on the sealing plate 2 side is located at the bottom.

[0067] like Figure 10AAs shown, the first positive electrode current collector 6a has a connection hole 6c. The edge of the connection hole 6c is welded to the deformable plate 62. Four fixing holes 6d are provided around the connection hole 6c in the first positive electrode current collector 6a. In addition, there may be one fixing hole 6d, but it is preferred that two or more are provided. In the first positive electrode current collector 6a, anti-deviation holes 6e are provided around the connection hole 6c. There may be one anti-deviation hole 6e, but it is preferred that at least two are provided. The anti-deviation hole 6e is preferably arranged between the fixing holes 6d and the fixing holes 6d. In addition, the fixing hole 6d preferably has a small diameter portion 6d1 and a large diameter portion 6d2 having an inner diameter larger than the small diameter portion 6d1. The large diameter portion 6d2 is preferably arranged closer to the electrode body 3 side than the small diameter portion 6d1.

[0068] As shown in Figure 8 and Figure 10A As shown, the second insulating member 63 includes a first insulating member region 63x positioned opposite the deformable plate 62; a second insulating member region 63y positioned opposite the sealing plate 2; and a third insulating member region 63z connecting the first and second insulating member regions 63x and 63y. A first insulating member opening 63a is provided in the center of the first insulating member region 63x. A third wall portion 63b is provided at the end of the first insulating member region 63x in the longitudinal direction of the sealing plate 2. A third connecting portion 63d is provided on the third wall portion 63b. Furthermore, fourth wall portions 63c are provided at both ends of the first insulating member region 63x in the transverse direction of the sealing plate 2. A fourth connecting portion 63e is provided on the fourth wall portion 63c. Four fixing protrusions 63f are provided on the surface of the first insulating member region 63x facing the electrode body 3. Two anti-slip protrusions 63g are also provided. Four claws 63h are provided on the surface of the insulating member first region 63x facing the sealing plate 2. The insulating member second region 63y is located closer to the sealing plate 2 than the insulating member first region 63x. A second insulating member opening 63i is provided in the insulating member second region 63y at a position opposing the electrolyte injection port 15 provided in the sealing plate 2. An insulating member annular rib 63k is provided at the edge of the insulating member second opening 63i, extending toward the electrode body 3.

[0069] like Figure 10B As shown in FIG. 1 , the first positive electrode current collector 6a is placed on the second insulating member 63 so that the fixing protrusion 63f of the second insulating member 63 is placed in the fixing hole 6d of the first positive electrode current collector 6a, and the deviation prevention protrusion 63g of the second insulating member 63 is placed in the deviation prevention hole 6e of the first positive electrode current collector 6a. Then, the front end of the fixing protrusion 63f of the second insulating member 63 is deformed by heat caulking or the like. As a result, as shown in FIG. Figure 8C as well as Figure 10CAs shown, an enlarged diameter portion 63f1 is formed at the distal end portion of the fixing protrusion 63f of the second insulating member 63 to fix the second insulating member 63 and the first positive electrode current collector 6a.

[0070] In addition, preferably Figure 8C As shown, the enlarged diameter portion 63f1 formed at the distal end portion of the fixing protrusion 63f of the second insulating member 63 is arranged in the large diameter portion 6d2 of the fixing hole 6d.

[0071] The deviation prevention protrusion 63 g of the second insulating member 63 is not thermally caulked like the fixing protrusion 63 f.

[0072] The outer diameter of the fixing protrusion 63f is preferably larger than the outer diameter of the anti-deviation protrusion 63g. The inner diameter of the small diameter portion 6d1 of the fixing hole 6d of the first positive current collector 6a is preferably larger than the inner diameter of the anti-deviation hole 6e of the first positive current collector 6a.

[0073] Next, if Figures 8A to 8C As shown, the second insulating member 63 to which the first positive electrode current collector 6 a is fixed is connected to the first insulating member 10 and the conductive member 61 .

[0074] like Figure 8B As shown in FIG. 1 , the fourth connecting portion 63e of the second insulating member 63 is connected to the first connecting portion 10e of the first insulating member 10. Figure 8C As shown, the claw portion 63h of the second insulating member 63 is connected to the flange portion 61d of the conductive member 61. Thus, the second insulating member 63 is connected to the first insulating member 10 and the conductive member 61, respectively. In addition, the second insulating member 63 does not necessarily have to be connected to both the first insulating member 10 and the conductive member 61. Among them, it is preferred that the second insulating member 63 is connected to at least one of the first insulating member 10 and the conductive member 61. Thus, even when a strong impact or vibration is applied to the square secondary battery 20, the load applied to the fragile portion of the first positive electrode collector 6a can be suppressed. Therefore, damage or breakage of the fragile portion of the first positive electrode collector 6a can be suppressed.

[0075] The deformable plate 62 is connected to the first positive electrode current collector 6 a by welding. Figure 11 yes Figure 8A An enlarged view of the vicinity of the connection between the deformed plate 62 and the first positive electrode current collector 6a. Figure 11As shown, the second protrusion 62a2 of the deformable plate 62 is positioned within the connection hole 6c of the first positive electrode current collector 6a. Furthermore, the second protrusion 62a2 of the deformable plate 62 and the edge of the connection hole 6c of the first positive electrode current collector 6a are welded together using laser welding or other methods. Furthermore, the connection between the deformable plate 62 and the first positive electrode current collector 6a is formed at a position corresponding to the first insulating member opening 63a of the second insulating member 63.

[0076] Furthermore, a thin-walled portion 6f is provided around the connection hole 6c in the first positive electrode current collector 6a. An annular notch 6g is provided in the thin-walled portion 6f to surround the connection hole 6c. An annular connecting rib 6h is formed at the edge of the connection hole 6c. This connecting rib 6h is welded to the deformable plate 62. Alternatively, the first positive electrode current collector 6a and the deformable plate 62 may be welded in an annular shape around the entire circumference of the connection hole 6c, or may be welded in a non-annular shape with a portion not welded. Alternatively, the first positive electrode current collector 6a and the deformable plate 62 may be welded at multiple, separate locations around the edge of the connection hole 6c.

[0077] Here, the operation of the current-interrupting mechanism 60 will be described. As the pressure within the battery case 100 increases, the center portion of the deformable plate 62 deforms in a manner that moves toward the sealing plate 2. Furthermore, when the pressure within the battery case 100 exceeds a given value, the deformation of the deformable plate 62 causes the notch 6g provided in the thin-walled portion 6f of the first positive electrode current collector 6a to rupture. As a result, the conductive path from the positive electrode plate 4 to the positive electrode terminal 7 is cut off. Thus, the current-interrupting mechanism 60 includes the first positive electrode current collector 6a, the deformable plate 62, and the conductive member 61. When the prismatic secondary battery 20 becomes overcharged and the pressure within the battery case 100 increases, the current-interrupting mechanism 60 operates, cutting off the conductive path from the positive electrode plate 4 to the positive electrode terminal 7, thereby preventing further overcharging. Furthermore, the operating pressure at which the current-interrupting mechanism 60 operates can be appropriately determined.

[0078] Before welding the deformable plate 62 to the first positive electrode current collector 6a, gas is introduced into the interior of the conductive member 61 through the terminal through-hole 7c formed in the positive electrode terminal 7. This allows leakage inspection of the weld between the conductive member 61 and the deformable plate 62. The terminal through-hole 7c is sealed by a terminal sealing member 7x. The terminal sealing member 7x is preferably composed of a metal member 7y and a rubber member 7z.

[0079] Figure 12 1 is a perspective view of the sealing plate 2 to which the first insulating member 10, the conductive member 61, the deformable plate 62, the second insulating member 63 and the first positive electrode current collector 6a are attached. Figure 12As shown, the second insulating member 63 has third connecting portions 63d provided at the longitudinal ends of the sealing plate 2. The first insulating member 10 has second connecting portions 10f provided at the transverse ends of the sealing plate 2.

[0080] [Installation of each component on the sealing plate (negative electrode side)]

[0081] use Figure 2 as well as Figure 13 Next, the method for attaching the negative electrode terminal 9 and the first negative electrode collector 8a to the sealing plate 2 is described. An external insulating member 13 is placed on the outer surface of the battery near the negative terminal mounting hole 2b of the sealing plate 2. An internal insulating member 12 and the first negative electrode collector 8a are placed on the inner surface of the battery near the negative terminal mounting hole 2b. Next, the negative electrode terminal 9 is inserted into the through-hole of the external insulating member 13, the negative terminal mounting hole 2b of the sealing plate 2, the through-hole of the internal insulating member 12, and the through-hole of the first negative electrode collector 8a. The tip of the negative electrode terminal 9 is then riveted to the first negative electrode collector 8a. This secures the external insulating member 13, the sealing plate 2, the internal insulating member 12, and the first negative electrode collector 8a. The riveted portion of the negative electrode terminal 9 and the first negative electrode collector 8a are preferably welded together using laser welding or other methods. In addition, the inner insulating member 12 and the outer insulating member 13 are preferably each made of resin.

[0082] [Connection between current collector and tab]

[0083] Figure 14 This diagram illustrates the method for connecting the positive electrode tab 40 to the second positive electrode current collector 6b and the method for connecting the negative electrode tab 50 to the second negative electrode current collector 8b. Two electrode body elements are fabricated using the above method, designated as the first electrode body element 3a and the second electrode body element 3b. The first electrode body element 3a and the second electrode body element 3b may have identical or different structures. Here, the multiple positive electrode tabs 40 of the first electrode body element 3a constitute a first positive electrode tab group 40a. The multiple negative electrode tabs 50 of the first electrode body element 3a constitute a first negative electrode tab group 50a. The multiple positive electrode tabs 40 of the second electrode body element 3b constitute a second positive electrode tab group 40b. The multiple negative electrode tabs 50 of the second electrode body element 3b constitute a second negative electrode tab group 50b.

[0084] A second positive electrode current collector 6b and a second negative electrode current collector 8b are arranged between the first electrode body element 3a and the second electrode body element 3b. Furthermore, a first positive electrode tab group 40a, consisting of a plurality of stacked positive electrode tabs 40 protruding from the first electrode body element 3a, is arranged on the second positive electrode current collector 6b, and a first negative electrode tab group 50a, consisting of a plurality of stacked negative electrode tabs 50 protruding from the first electrode body element 3a, is arranged on the second negative electrode current collector 8b. Furthermore, a second positive electrode tab group 40b, consisting of a plurality of stacked positive electrode tabs 40 protruding from the second electrode body element 3b, is arranged on the second positive electrode current collector 6b, and a second negative electrode tab group 50b, consisting of a plurality of stacked negative electrode tabs 50 protruding from the second electrode body element 3b, is arranged on the second negative electrode current collector 8b. The first positive electrode tab group 40a and the second positive electrode tab group 40b are each welded to the second positive electrode current collector 6b, forming welded connection portions 90. The first negative electrode tab group 50a and the second negative electrode tab group 50b are each welded to the second negative electrode current collector 8b, forming welded connection portions 90. Welding can be performed as follows.

[0085] The stacked convex pieces (the first positive electrode convex piece group 40a, the second positive electrode convex piece group 40b, the first negative electrode convex piece group 50a, the second negative electrode convex piece group 50b) and the collector (the second positive electrode collector 6b, the second negative electrode collector 8b) are clamped and welded from the top and bottom by a welding fixture. Here, the welding method is preferably ultrasonic welding or resistance welding. In addition, a pair of welding fixtures is a pair of resistance welding electrodes in the case of resistance welding, and a welding head and anvil in the case of ultrasonic welding. In addition, the connection between the convex pieces (the first positive electrode convex piece group 40a, the second positive electrode convex piece group 40b, the first negative electrode convex piece group 50a, the second negative electrode convex piece group 50b) and the collector (the second positive electrode collector 6b, the second negative electrode collector 8b) can also be connected by laser welding.

[0086] like Figure 14 As shown, the second positive electrode current collector 6b has a first collector region 6b1 and a second collector region 6b2. The positive electrode tab 40 is connected to the first collector region 6b1. A second collector opening 6z is provided in the first collector region 6b1. The first collector region 6b1 and the second collector region 6b2 are connected via the third collector region 6b3. After the second positive electrode current collector 6b is connected to the first positive electrode current collector 6a, the second collector opening 6z is arranged at a position corresponding to the electrolyte injection hole 15 provided in the sealing plate 2. The first collector opening 6y is provided in the second collector region 6b2. In addition, a first collector recess 6m is provided around the first collector opening 6y. In addition, target holes 6k are provided on both sides of the first collector opening 6y in the short side direction of the sealing plate 2.

[0087] like Figure 14As shown, the second negative electrode current collector 8b has a first current collector region 8b1 and a second current collector region 8b2. A negative electrode tab 50 is connected to the first current collector region 8b1. A first current collector opening 8y is provided in the second current collector region 8b2. Furthermore, a first current collector recess 8f is provided around the first current collector opening 8y. Furthermore, target holes 8e are provided on both sides of the first current collector opening 8y in the short-side direction of the sealing plate 2.

[0088] [Connection between the First Positive Electrode Current Collector and the Second Positive Electrode Current Collector]

[0089] like Figure 2 、 Figure 7 8 , etc., the second positive current collector 6b is placed on the second insulating member 63 so that the collector protrusion 6x of the first positive current collector 6a is positioned within the first collector opening 6y of the second positive current collector 6b. Furthermore, the edges of the collector protrusion 6x of the first positive current collector 6a and the first collector opening 6y of the second positive current collector 6b are welded by irradiation with energy beams such as laser light. This connects the first positive current collector 6a and the second positive current collector 6b. Furthermore, the first positive current collector 6a and the second positive current collector 6b are preferably welded together at the first collector recess 6m.

[0090] like Figure 2 As shown in Figure 8 , in a direction perpendicular to the sealing plate 2, the distance between the sealing plate 2 and the first current collector region 6b1 is smaller than the distance between the sealing plate 2 and the second current collector region 6b2. This structure further reduces the space occupied by the current collector, resulting in a prismatic secondary battery with a higher volumetric energy density.

[0091] When welding the first positive electrode current collector 6 a and the second positive electrode current collector 6 b by irradiation with energy beams such as laser light, it is preferable to use the target hole 6 k as a target for image correction.

[0092] like Figure 8A As shown, a second current collector recess 6w is formed on the surface of the first positive electrode current collector 6a that faces the second insulating member 63 and on the back side of the current collector protrusion 6x. This is preferred because it facilitates forming a larger welded connection between the first positive electrode current collector 6a and the second positive electrode current collector 6b. Furthermore, the formation of the second current collector recess 6w prevents damage to the second insulating member 63 due to heat during welding when the first and second positive electrode current collectors 6a, 6b are welded together.

[0093] [Connection between the First Negative Electrode Current Collector and the Second Negative Electrode Current Collector]

[0094] like Figure 13As shown, the second negative electrode current collector 8b has a first current collector region 8b1 and a second current collector region 8b2. A negative electrode tab 50 is connected to the first current collector region 8b1. A first current collector opening 8y is provided in the second current collector region 8b2. The first current collector region 8b1 and the second current collector region 8b2 are connected via a third current collector region 8b3.

[0095] like Figure 13 As shown, the second negative current collector 8b is positioned on the inner insulating member 12 so that the collector protrusion 8x of the first negative current collector 8a is located within the first collector opening 8y of the second negative current collector 8b. Furthermore, the edges of the collector protrusion 8x of the first negative current collector 8a and the first collector opening 8y of the second negative current collector 8b are welded by irradiation with energy beams such as laser. Thus, the first negative current collector 8a and the second negative current collector 8b are connected. Preferably, the first negative current collector 8a and the second negative current collector 8b are welded together in the first collector recess 8f. A target hole 8e is provided in the second negative current collector 8b, similar to the second positive current collector 6b. In the direction perpendicular to the sealing plate 2, the distance between the sealing plate 2 and the current collector first region 8b1 is smaller than the distance between the sealing plate 2 and the current collector second region 8b2. Furthermore, the second negative electrode current collector 8b can be connected to the negative electrode terminal 9 without using the first negative electrode current collector 8a.

[0096] like Figure 13 As shown, a second current collector recess 8w is formed on the surface of the first negative electrode current collector 8a that faces the inner insulating member 12 and on the back side of the current collector protrusion 8x. This is preferred because it facilitates forming a larger welded connection between the first negative electrode current collector 8a and the second negative electrode current collector 8b. Furthermore, the formation of the second current collector recess 8w prevents damage to the inner insulating member 12 due to heat during welding when the first and second negative electrode current collectors 8a, 8b are welded together.

[0097] Furthermore, the current collector protrusions 6 x and 8 x preferably have a non-circular shape in plan view, and preferably a square shape, an elliptical shape, or a racetrack shape.

[0098] [Installation of the cover]

[0099] Figure 15 : is a perspective view of the sealing plate 2 and the outer cover 80 with various components installed. Figure 15The positive electrode tab 40 is not shown. The outer cover 80 includes a main cover body 80a positioned opposite the first positive electrode current collector 6a, and a pair of arm portions 80b extending from both ends of the main cover body 80a in the short direction of the sealing plate 2 toward the sealing plate 2. The outer cover 80 includes a wall portion 80e extending from the ends of the main cover body 80a in the long direction of the sealing plate 2 toward the sealing plate 2. Connecting protrusions 80c are provided on the inner surface of the arm portion 80b. A root opening 80d is provided near the base of the arm portion 80b in the main cover body 80a. A wall opening 80f is provided in the wall portion 80e.

[0100] like Figure 16A as well as Figure 16B As shown, the cover 80 is connected to the first insulating member 10 and the second insulating member 63 so that the cover body 80a of the cover 80 faces the first positive electrode current collector 6a. The pair of arm portions 80b of the cover 80 are connected to the second connecting portion 10f of the first insulating member 10 via connecting protrusions 80c. The cover wall portion 80e of the cover 80 is connected to the third connecting portion 63d of the second insulating member 63.

[0101] like Figure 17A As shown, the third connecting portion 63d is a protrusion provided on the third wall portion 63b, and the first insulating member 10 and the outer cover portion 80 are connected by fitting the third connecting portion 63d with the wall opening 80f of the outer cover wall portion 80e. Figure 17B As shown, the second connecting portion 10 f of the first insulating member 10 is hooked onto a connecting protrusion 80 c provided on the arm portion 80 b of the cover portion 80 , thereby achieving connection.

[0102] In addition, the cover part 80 is preferably made of resin. In addition, the cover part 80 is preferably made of an insulating member.

[0103] like Figure 17A as well as Figure 17B As shown, a gap is preferably formed between the first positive electrode current collector 6a and the upper surface of the outer cover body 80a of the outer cover 80. This structure allows gas to flow smoothly into the lower surface of the deformable plate 62, so that when the pressure in the battery case 100 exceeds a predetermined value, the deformable plate 62 deforms more smoothly. However, this gap is not a required structure.

[0104] like Figure 17B As shown, it is preferable to provide a base opening 80d in the outer cover body 80a of the outer cover 80. This allows gas to flow smoothly into the lower surface of the deformable plate 62, so that the deformable plate 62 deforms more smoothly when the pressure within the battery case 100 exceeds a predetermined value. However, the base opening 80d is not a required feature.

[0105] [Electrode body production]

[0106] The first positive electrode tab group 40a, the second positive electrode tab group 40b, the first negative electrode tab group 50a, and the second negative electrode tab group 50b are bent so that Figure 14 The upper surface of the first electrode body element 3a and the upper surface of the second electrode body element 3b are in contact directly or through another member. Thus, the first electrode body element 3a and the second electrode body element 3b are integrated into one electrode body 3. Furthermore, the first electrode body element 3a and the second electrode body element 3b are preferably integrated into one by using a belt or the like. Alternatively, the first electrode body element 3a and the second electrode body element 3b are preferably integrated into one by placing them within an insulating sheet 14 formed into a box or bag shape.

[0107] [Assembly of Prismatic Secondary Batteries]

[0108] The electrode body 3 mounted on the sealing plate 2 is covered with an insulating sheet 14 and inserted into the square packaging body 1. In addition, the insulating sheet 14 is preferably formed by bending a sheet on a flat plate into a box shape or a bag shape. Furthermore, the sealing plate 2 and the square packaging body 1 are joined by laser welding or the like to seal the opening of the square packaging body 1. Thereafter, a non-aqueous electrolyte containing an electrolyte solvent and an electrolyte salt is injected into the battery case 100 from the electrolyte injection hole 15 provided on the sealing plate 2. Then, the electrolyte injection hole 15 is sealed with a sealing plug 16. Thus, a square secondary battery 20 is manufactured.

[0109] [Regarding the square secondary battery 20]

[0110] As shown in Figures 8, 17 and Figure 18 As shown, a pressing protrusion 61e that protrudes toward the first insulating member 10 is provided in the portion of the conductive member 61 that is opposite to the first insulating member 10. Thus, the pressing protrusion 61e presses the first insulating member 10 more strongly against the sealing plate 2. Therefore, it is possible to suppress the gas present around the electrode body 3 from passing between the sealing plate 2 and the first insulating member 10 or between the first insulating member 10 and the conductive member 61 and moving to the vicinity of the connection portion between the conductive member 61 and the positive terminal 7. Therefore, it is possible to suppress the gas from passing between the conductive member 61 and the positive terminal 7 and moving into the space formed by the conductive member 61 and the deformable plate 62. Therefore, when an abnormality occurs in the square secondary battery 20 and the pressure in the square package 1 rises, the current interruption mechanism 60 can be operated more stably. Thus, a square secondary battery 20 with higher reliability is achieved.

[0111] In addition, the pressing protrusion 61e is formed on the surface of the conductive member base portion 61a of the conductive member 61 on the sealing plate 2 side. Preferably, when the conductive member 61 and the positive terminal 7 are viewed from a direction perpendicular to the sealing plate 2, the pressing protrusion 61e and the riveted portion 7d (the enlarged portion) of the insertion portion 7b of the positive terminal 7 are in an overlapping position. In addition, the pressing protrusion 61e is preferably formed at the edge of the third terminal insertion hole 61c of the conductive member 61. However, the pressing protrusion 61e can also be formed at a portion away from the edge of the third terminal insertion hole 61c of the conductive member 61. In addition, the pressing protrusion 61e is preferably annular in shape when viewed from above. However, the pressing protrusion 61e does not necessarily have to be annular in shape when viewed from above, and can also be a shape with a portion of the annular shape removed. For example, the length of the pressing protrusion 61e can be made 70% or more of the length when it is set as annular. Furthermore, providing the pressing protrusion 61 e on the conductive member 61 is preferable because the pressing protrusion 61 e can be easily formed into a desired shape.

[0112] The first insulating member 10 pressed by the pressing protrusion 61e is deformed in the horizontal direction (a direction parallel to the sealing plate 2). Figure 18 In the case of escaping (in the center left direction), the first insulating member 10 may have a gap between the deformed sealing plate 2 and the first insulating member 10 or between the first insulating member 10 and the conductive member 61. Such a problem can be eliminated by providing a groove portion in the portion of the first insulating member 10 that is arranged between the sealing plate 2 and the conductive member 61 and further outward from the pressing protrusion 61e in the radial direction of the second terminal insertion hole 10d of the first insulating member 10. For example, it is preferred that the first groove portion 10x be provided on the surface of the first insulating member 10 that faces the sealing plate 2. In addition, it is preferred that the second groove portion 10y be provided on the surface of the first insulating member 10 that faces the conductive member 61 in addition to or instead of the first groove portion 10x. In addition, it is also possible to provide only one of the first groove portion 10x and the second groove portion 10y on the first insulating member 10. Furthermore, the first insulating member 10 may have a second groove 10y on the surface facing the sealing plate 2 and a first groove 10x on the surface facing the conductive member 61. The first groove 10x and the second groove 10y are not essential structures.

[0113] Furthermore, the first groove portion 10x is preferably annular in shape when viewed from above. The second groove portion 10y is preferably annular in shape when viewed from above. However, the first groove portion 10x and the second groove portion 10y do not necessarily need to be annular in shape when viewed from above, and can also be formed with a portion of the annular shape removed. For example, the length of the first groove portion 10x or the second groove portion 10y can be set to be 70% or more of the length when the groove portion is annular.

[0114] When grooves are provided on both surfaces of the first insulating member 10, it is preferred that one groove be provided further outward than the other groove in the radial direction of the second terminal insertion hole 10d of the first insulating member 10. In other words, when grooves are provided on both surfaces of the first insulating member 10, it is preferred that the distance from one groove to the second terminal insertion hole 10d of the first insulating member 10 is greater than the distance from the second terminal insertion hole 10d of the first insulating member 10 to the other groove.

[0115] In addition, in the radial direction of the second terminal insertion hole 10d of the first insulating member 10, the distance between the center of one groove portion and the center of the other groove portion ( Figure 18 The distance D) in the middle is preferably 0.5 mm to 10 mm, more preferably 0.5 mm to 5 mm.

[0116] For example, in the first insulating member 10, the second groove portion 10y is located outside the first groove portion 10x in the radial direction of the second terminal insertion hole 10d of the first insulating member 10. Figure 18 As shown in FIG, the distance D between the center of the width direction of the first groove portion 10x and the center of the width direction of the second groove portion 10y is preferably 0.5 mm to 10 mm, more preferably 0.5 mm to 5 mm. Figure 18 The width in the left-right direction is preferably 0.5 mm to 2 mm.

[0117] Preferably, a portion of the first groove 10x and a portion of the second groove 10y overlap when viewing the first insulating member 10 from above. However, preferably, the first groove 10x and the second groove 10y do not completely overlap when viewing the first insulating member 10 from above. This structure can more effectively suppress deflection of the first insulating member 10.

[0118] The width of the pressing protrusion 61e in the radial direction of the third terminal insertion hole 61c of the conductive member 61 is preferably set to 5 mm or less, more preferably 2 mm. Furthermore, the distance between the pressing protrusion 61e in the radial direction of the third terminal insertion hole 61c of the conductive member 61 and the first groove portion 10x is preferably set to 0.5 mm to 5 mm, more preferably 0.5 mm to 2 mm, and even more preferably 0.5 mm to 1 mm.

[0119] Furthermore, it is particularly effective when the first insulating member 10 is relatively soft, for example, when it is made of perfluoroalkoxyalkane (PFA), polytetrafluoroethylene (PTFE), or the like.

[0120] like Figure 18As shown, it is preferable to provide a tapered portion 61g at the end of the third terminal insertion hole 61c of the conductive member 61 on the electrode body 3 side. With this structure, it is difficult to form a gap between the positive electrode terminal 7 and the conductive member 61, and gas can be more effectively suppressed from passing between the positive electrode terminal 7 and the conductive member 61.

[0121] Furthermore, the conductive member 61 is preferably made of aluminum or an aluminum alloy. The positive electrode terminal 7 is preferably made of aluminum or an aluminum alloy.

[0122] As shown in Figure 10, the second insulating member 63 is secured to the first positive current collector 6a by inserting the fixing protrusion 63f of the second insulating member 63 into the fixing hole 6d of the first positive current collector 6a and expanding the diameter of the distal end of the fixing protrusion 63f to form an expanded diameter portion 63f1. This structure can suppress the application of loads to fragile portions of the first positive current collector 6a, such as the thin-walled portion 6f and the notch 6g, when the prismatic secondary battery 20 is subjected to strong impact or vibration. It is particularly preferred that the second insulating member 63 be connected to at least one of the first insulating member 10 and the conductive member 61.

[0123] If the second insulating member 63 is made of resin, after the fixing protrusion 63f of the second insulating member 63 is inserted into the fixing hole 6d of the first positive electrode current collector 6a, when the front end of the fixing protrusion 63f is expanded, deformation or shrinkage of the fixing protrusion 63f may create a gap between the side surface of the fixing protrusion 63f and the inner surface of the fixing hole 6d. Furthermore, if such a gap exists, the first positive electrode current collector 6a may be misaligned relative to the second insulating member 63 in a direction parallel to the sealing plate 2 when a strong impact or vibration is applied to the prismatic secondary battery 20. Furthermore, if the front end of the fixing protrusion 63f is expanded while being heated, the portion of the fixing protrusion 63f located within the fixing hole 6d is likely to shrink due to the heat, resulting in the aforementioned gap.

[0124] In the prismatic secondary battery 20, the second insulating member 63 includes a deviation preventing protrusion 63g, which is positioned within the deviation preventing hole 6e of the first positive electrode current collector 6a. Furthermore, the deviation preventing protrusion 63g is not enlarged in diameter like the fixing protrusion 63f. Therefore, even if a gap forms between the fixing protrusion 63f and the fixing hole 6d, the engagement of the deviation preventing protrusion 63g with the deviation preventing hole 6e effectively prevents the first positive electrode current collector 6a from deviating from the second insulating member 63.

[0125] Furthermore, it is preferred that a plurality of fixing protrusions 63f be formed around the connection between the deformable plate 62 and the first positive electrode current collector 6a, and it is particularly preferred that four or more protrusions be provided. Furthermore, it is preferred that the anti-deviation protrusions 63g be formed on both sides of the connection between the deformable plate 62 and the first positive electrode current collector 6a. Furthermore, it is preferred that the anti-deviation protrusions 63g be formed between the fixing protrusions 63f and the fixing protrusions 63f.

[0126] In addition, it is preferable that the diameter of the fixing protrusion 63f is larger than the diameter of the deviation preventing protrusion 63g.

[0127] When two deviation preventing holes 6e are formed, the inner diameter of one can be made larger than the other. Also, when two deviation preventing protrusions 63g are formed, the outer diameter of one can be made larger than the other.

[0128] The ratio of the outer diameter of the anti-deviation protrusion 63g to the inner diameter of the anti-deviation hole 6e is preferably 0.95 to 1. The difference between the inner diameter of the anti-deviation hole 6e and the outer diameter of the anti-deviation protrusion 63g is preferably 0.1 mm or less.

[0129] In addition, when a plurality of interlocking parts of the anti-deviation holes 6e and the anti-deviation protrusions 63g are provided, the difference between the inner diameter of the anti-deviation hole 6e in one interlocking part and the outer diameter of the anti-deviation protrusion 63g and the difference between the inner diameter of the anti-deviation hole 6e and the outer diameter of the anti-deviation protrusion 63g in other interlocking parts can be set to different values.

[0130] The deviation prevention hole 6e is not a notch formed at the edge of the first positive electrode current collector 6a. Preferably, the edge of the deviation prevention hole 6e is annular. In other words, the first positive electrode current collector 6a is preferably present along the entire circumference of the side surface of the deviation prevention projection 63g. This can more effectively suppress deviation.

[0131] Preferably, anti-deviation holes 6e are provided on both sides of the connection between the deformable plate 62 and the first positive electrode current collector 6a in the short-side direction of the sealing plate 2. Furthermore, the connection between the deformable plate 62 and the first positive electrode current collector 6a is preferably positioned between the two anti-deviation holes 6e, and the connection between the deformable plate 62 and the first positive electrode current collector 6a is preferably positioned on a straight line connecting the two anti-deviation holes 6e. This more reliably reduces the application of load to the connection between the deformable plate 62 and the first positive electrode current collector 6a, the thin-walled portion 6f, and the notch 6g.

[0132] The fixing protrusion 63f preferably has a recessed portion at the front end before the front end is expanded. With this configuration, the front end of the fixing protrusion 63f can be expanded while suppressing the load applied to the base side of the fixing protrusion 63f.

[0133] As shown in Figures 16 and 17, an outer cover portion 80 is arranged between the first positive electrode collector 6a and the electrode body 3. By having such a structure, even if a strong impact or vibration is applied to the square secondary battery 20 and the electrode body 3 moves toward the sealing plate 2, it is possible to prevent the electrode body 3 from contacting the first positive electrode collector 6a and preventing the thin-walled portion 6f, notch 6g and other fragile portions of the first positive electrode collector 6a, and the connection between the deformable plate 62 and the first positive electrode collector 6a from being damaged or broken. As a result, a secondary battery with higher reliability can be obtained. In addition, the outer cover portion 80 is preferably made of resin. In addition, the outer cover portion 80 is preferably electrically insulating.

[0134] The outer cover 80 is preferably a separate component from the first insulating member 10 and the second insulating member 63. For example, if the outer cover 80 is a separate component from the first insulating member 10 and the second insulating member 63, assembly of the secondary battery becomes simpler. Furthermore, by making the outer cover 80 and the second insulating member 63 separate components, a protrusion can be provided on the surface of the second insulating member 63 facing the first positive electrode current collector 6a, thereby achieving a more secure connection between the second insulating member 63 and the first positive electrode current collector 6a.

[0135] A gap is preferably provided between the first positive electrode current collector 6a and the cover body 80a of the cover 80. Furthermore, the distance between the electrode body-side surface of the first positive electrode current collector 6a and the sealing plate-side surface of the cover body 80a is preferably 0.1 mm to 5 mm, more preferably 0.5 to 2 mm.

[0136] Furthermore, the portion of the cover 80 that extends from the cover body 80a toward the sealing plate 2 is preferably connected to at least one of the first insulating member 10 and the second insulating member 63, thereby forming a gap between the first positive electrode current collector 6a and the cover body 80a. With this structure, even if the electrode body 3 moves toward the sealing plate 2 and contacts the cover 80, the cover 80 can absorb some of the impact, thereby preventing damage to the electrode body 3.

[0137] The cover portion 80 is preferably connected to at least one of the first insulating member 10 and the second insulating member 63. Furthermore, the cover portion 80 is more preferably connected to each of the first insulating member 10 and the second insulating member 63. For example, the cover portion 80 preferably includes a cover portion body 80a and a pair of arm portions 80b extending from the cover portion body 80a toward the sealing plate 2, wherein the arm portions 80b are connected to the first insulating member 10. Furthermore, the cover portion body 80a is preferably provided with a cover wall portion 80e, and the cover wall portion 80e is preferably connected to the second insulating member 63.

[0138] It is preferable to provide a through hole in the cover body 80a. With such a structure, gas can flow smoothly to the lower side of the deformable plate 62. It is preferable to provide a base opening 80d as a through hole in the cover body 80a at the base of the arm 80b.

[0139] When the positive electrode current collecting member includes a first positive electrode collector 6a and a second positive electrode collector 6b, a cover portion 80 is preferably disposed between the connection portion between the first and second positive electrode collectors 6a, 6b and the electrode body 3. With this structure, even if the prismatic secondary battery 20 is subjected to strong vibration or impact, causing the electrode body 3 to move toward the sealing plate 2, the electrode body 3 can be prevented from contacting the connection portion between the first and second positive electrode collectors 6a, 6b, thereby preventing damage or breakage of the connection portion between the first and second positive electrode collectors 6a, 6b. Furthermore, it is preferred that, on the surface of the cover portion main body 80a facing the first positive electrode collector 6a, the portion facing the connection portion between the first and second positive electrode collectors 6a, 6b be more recessed than the portion facing the connection portion between the deformable plate 62 and the first positive electrode collector 6a.

[0140] Furthermore, it is preferable to connect the cover 80 to at least one of the first insulating member 10 and the second insulating member 63 after connecting the second positive current collector 6 b to which the positive electrode tab 40 is connected to the first positive current collector 6 a connected to the deformable plate 62 .

[0141] As shown in Figure 8 and Figure 9 As shown in FIG. 1 , the deformable plate 62 has a portion on its outer periphery facing the electrode body 3 ( Figure 9 An annular rib 62b protrudes from the upper center of the tubular portion 61b of the conductive member 61. The annular rib 62b is fitted into the end of the tubular portion 61b of the conductive member 61 on the electrode body 3 side and welded to the conductive member 61. Furthermore, an annular thin-walled portion 62c is provided on the deformable plate 62 on a side closer to the center than the annular rib 62b. With such a structure, even when the thickness of the deformable plate 62 is increased, the deformable plate 62 deforms more smoothly when the pressure inside the square package 1 exceeds a given value, making it preferable. Furthermore, the heat capacity of the deformable plate 62 can be increased by increasing the thickness of the deformable plate 62. Therefore, even when heat is generated in fragile portions such as the thin-walled portion 6f or the notch 6g of the first positive electrode current collector 6a, the heat can be prevented from being transferred to the deformable plate 62 side and causing the fragile portions such as the thin-walled portion 6f or the notch 6g of the first positive electrode current collector 6a to melt. Furthermore, it is preferable to provide an annular connecting rib 6h at the edge of the connecting hole 6c of the first positive electrode current collector 6a. This increases the heat capacity near the weak portions such as the thin portion 6f and the notch 6g of the first positive electrode current collector 6a, thereby more effectively preventing the weak portions such as the thin portion 6f and the notch 6g of the first positive electrode current collector 6a from melting.

[0142] Furthermore, the deformable plate 62 is preferably shaped so as to be inclined relative to the sealing plate 2 from the outer periphery toward the center. The annular thin-walled portion 62c is preferably formed by providing a recessed portion on the surface of the deformable plate 62 facing the electrode body 3. This configuration allows the deformable plate 62 to deform more smoothly. Furthermore, the width of the annular thin-walled portion 62c, when viewed from above, is preferably 1 mm to 3 mm, more preferably 1.5 mm to 2 mm.

[0143] Furthermore, even after the gas exhaust valve 17 ruptures and the gas in the battery case 100 is exhausted to the outside of the battery case 100 , the deformable plate 62 does not rupture, and the conductive member opening 61 f of the conductive member 61 is also sealed by the deformable plate 62 .

[0144] like Figure 9 as well as Figure 11 As shown, the deformable plate 62 has a stepped protrusion 62a in its center, consisting of a first protrusion 62a1 and a second protrusion 62a2. Furthermore, the second protrusion 62a2 engages with the connection hole 6c provided in the first positive electrode current collector 6a. The outer diameter of the first protrusion 62a1 is larger than the inner diameter of the connection hole 6c, so that the surface of the first protrusion 62a1 facing the electrode body 3 contacts the upper surface 6i of the first positive electrode current collector 6a. With this structure, when the connection between the second protrusion 62a2 of the deformable plate 62 and the connection hole 6c of the first positive electrode current collector 6a is irradiated with energy radiation, such as laser radiation, the energy radiation is prevented from passing between the first protrusion 62a1 and the sidewall of the connection hole 6c of the first positive electrode current collector 6a and being scattered on the upper surface of the first positive electrode current collector 6a. This effectively prevents damage or breakage of various components due to the energy radiation. The stepped protrusion 62a preferably has a stepped recess on the surface facing the sealing plate 2. The bottom 62d of the stepped recess is preferably located closer to the sealing plate 2 than the upper surface 6i of the first positive electrode current collector 6a.

[0145] Modification 1

[0146] The rectangular secondary battery according to the first modification has the same structure as the rectangular secondary battery 20 according to the embodiment except for the shape of the outer cover. Figure 19A as well as Figure 19B As shown, the cover portion 81 according to Modification 1 includes a cover body 81a positioned to face the first positive electrode current collector 6a, and a pair of arm portions 81b extending from both ends of the cover body 81a in the short-side direction of the sealing plate 2 toward the sealing plate 2. The cover portion also includes a cover wall portion 81e extending from the ends of the cover body 81a in the long-side direction of the sealing plate 2 toward the sealing plate 2. Connecting protrusions are provided on the inner surfaces of the arm portions 81b. These connecting protrusions are connected to the second connecting portion 10f of the first insulating member 10.

[0147] The outer cover body 81a has a base opening 81d near the base of the arm 81b. The outer cover wall 81e has a wall opening 81f. In the outer cover 81 of the prismatic secondary battery according to Modification 1, the outer cover body 81a has an outer cover opening 81x. The outer cover opening 81x is located opposite the connection between the deformable plate 62 and the first positive electrode current collector 6a. This allows the current interruption mechanism to operate more smoothly.

[0148] Modification 2

[0149] In the prismatic secondary battery 20 according to the above embodiment, a pressing protrusion 61e is provided on the portion of the conductive member 61 that faces the first insulating member 10. The prismatic secondary battery according to Modification 2 has the same structure as the prismatic secondary battery 20 according to the above embodiment, except that a pressing protrusion is provided on the portion of the sealing plate that faces the first insulating member 10, instead of on the conductive member.

[0150] Figure 20 It is a cross-sectional view near the current interruption mechanism of the secondary battery according to Modification 2. Figure 20 is with Figure 8B The corresponding cross-sectional view. Figure 20 As shown in the figure, a pressing protrusion 102x is provided in the portion of the sealing plate 102 that is opposite to the first insulating member 10. If it is such a structure, the first insulating member 10 will be pressed more strongly by the pressing protrusion 102x, which can prevent the gas from moving to the connection portion between the conductive member 161 and the positive terminal 7. Therefore, it is possible to prevent the gas present near the electrode body from leaking into the space formed by the conductive member 161 and the deformable plate 62. Therefore, it is possible to suppress the operation delay of the current interruption mechanism. In addition, if a pressing protrusion 102x is provided on the sealing plate 102, it is easy to prevent the first insulating member 10 from deforming in such a way that the outer peripheral portion of the first insulating member 10 is warped toward the electrode body 3 side. In addition, the pressing protrusion 102x is preferably annular in shape when viewed from above.

[0151] When the sealing plate 102 and the positive electrode terminal 7 are viewed from a direction perpendicular to the sealing plate 102 , the pressing protrusion 102 x and the caulked portion 7 d (diameter-expanded portion) of the insertion portion 7 b of the positive electrode terminal 7 are preferably positioned so as to overlap.

[0152] In the prismatic secondary battery according to Modification 2, the pressing protrusion is not provided on the conductive member 161 . However, the pressing protrusion may be provided on the conductive member 161 .

[0153] <Other>

[0154] The predetermined rupture portion that ruptures as the deformable plate deforms is preferably a fragile portion provided on the current collecting member, a connection between the current collecting member and the deformable plate, or a fragile portion provided on the deformable plate.

[0155] The first insulating member, the second insulating member, and the cover are preferably made of resin, for example, polypropylene, polyethylene, perfluoroalkoxyalkane (PFA), polytetrafluoroethylene (PTFE), or ethylene-tetrafluoroethylene copolymer (ETFE).

[0156] In the above embodiment, an example is shown in which the electrode body 3 is composed of two electrode body elements (3a, 3b), but the present invention is not limited to this. The electrode body 3 may be a stacked electrode body. In addition, the electrode body 3 may also be a wound electrode body formed by winding a long positive electrode plate and a long negative electrode plate with a separator between them. In addition, each of the two electrode body elements (3a, 3b) is not limited to a stacked electrode body, and may also be a wound electrode body formed by winding a long positive electrode plate and a long negative electrode plate with a separator between them.

[0157] Preferably, when the electrode body is a laminated electrode body having multiple positive plates and multiple negative plates, or when the electrode body is a wound electrode body and its winding axis is configured to be perpendicular to the sealing plate, in the electrode body, the end of the positive plate, the end of the negative plate and the end of the separator are located on the sealing plate side. If such a structure is used, the electrolyte injection hole is provided in the sealing plate, and the injection property of the electrolyte into the electrode body is improved. In such a case, it is preferred that the end of the sealing plate side of the separator protrudes further toward the sealing plate 2 side compared with the end of the sealing plate side of the negative electrode active material mixture layer in the negative plate. In addition, it is preferred that in the electrode body, the end of the sealing plate side of the separator protrudes further toward the sealing plate side compared with the end of the sealing plate side of the positive electrode active material mixture layer in the positive plate. In addition, it is preferred that the positive plate and the separator are bonded by an adhesive layer, and the negative plate and the separator are bonded by an adhesive layer. With this structure, it is possible to reliably prevent the positive electrode active material mixture layer and the negative electrode active material mixture layer from coming into contact with the second insulating member and causing damage to the positive electrode active material layer or the negative electrode active material layer.

[0158] Description of Reference Numerals

[0159] 20 square secondary batteries

[0160] 1 square packaging

[0161] 2 Sealing plate

[0162] 2a Positive terminal mounting hole

[0163] 2b Negative terminal mounting hole

[0164] 100 battery housing

[0165] 3 Electrode body

[0166] 3a Element of the first electrode body

[0167] 3b Second electrode element

[0168] 4 positive plates

[0169] 4a Positive electrode core

[0170] 4b Positive electrode active material mixture layer

[0171] 4d positive electrode protection layer

[0172] 40 positive electrode tab

[0173] 40a 1st positive electrode tab group

[0174] 40b Second positive electrode tab group

[0175] 5 Negative plate

[0176] 5a Negative electrode core

[0177] 5b Negative electrode active material mixture layer

[0178] 50 negative electrode tab

[0179] 50a 1st negative electrode tab group

[0180] 50b Second negative electrode tab group

[0181] 6. Positive electrode current collecting component

[0182] 6a First positive electrode current collector

[0183] 6c connection hole

[0184] 6d fixing hole

[0185] 6d1 small diameter part

[0186] 6d2 Large diameter part

[0187] 6e Anti-deviation hole

[0188] 6f thin-walled part

[0189] 6g notch

[0190] 6h connecting rib

[0191] 6i top surface

[0192] 6x current collector protrusions

[0193] 6w 2nd concave part of current collector

[0194] 6b Second positive electrode current collector

[0195] 6b1 Current collector region 1

[0196] 6b2 Current collector second region

[0197] 6b3 Current collector third region

[0198] 6k target hole

[0199] 6m First concave portion of current collector

[0200] 6y Current collector first opening

[0201] 6z collector second opening

[0202] 7 Positive terminal

[0203] 7a convex edge

[0204] 7b Insertion

[0205] 7c terminal through hole

[0206] 7d Riveted part

[0207] 7x Terminal sealing components

[0208] 7y Metal components

[0209] 7z rubber component

[0210] 8 Negative electrode current collecting component

[0211] 8a First negative electrode current collector

[0212] 8x current collector protrusions

[0213] 8w 2nd concave part of current collector

[0214] 8b Second negative electrode current collector

[0215] 8b1 Current collector region 1

[0216] 8b2 Current collector second region

[0217] 8b3 Current collector third region

[0218] 8e Target Hole

[0219] 8f 1st recessed part of current collector

[0220] 8y Current collector first opening

[0221] 9 Negative terminal

[0222] 10 First insulating member

[0223] 10a First insulating member main body

[0224] 10b First side wall

[0225] 10c Second side wall

[0226] 10d Second terminal insertion hole

[0227] 10e 1st connection

[0228] 10f Second connection

[0229] 10g concave part

[0230] 10x Slot 1

[0231] 10y Slot 2

[0232] 11 External insulation member

[0233] 11a 1st terminal insertion hole

[0234] 12 Internal insulation member

[0235] 13 External insulation member

[0236] 14 Insulation sheet

[0237] 15 Electrolyte injection hole

[0238] 16 sealing plug

[0239] 17 Gas exhaust valve

[0240] 60 Current interruption mechanism

[0241] 61 conductive components

[0242] 61a Conductive member base

[0243] 61b Tubular portion

[0244] 61c Third terminal insertion hole

[0245] 61d flange

[0246] 61e Press tab

[0247] 61f conductive member opening

[0248] 61g tapered part

[0249] 62 Deformed Plate

[0250] 62a Step protrusion

[0251] 62a1 First protrusion

[0252] 62a2 Second protrusion

[0253] 62b Annular rib

[0254] 62c Annular thin-walled portion

[0255] 62d Bottom of stepped recess

[0256] 63 Second insulating member

[0257] 63x Insulation component area 1

[0258] 63a: First opening of insulating member

[0259] 63b Third wall

[0260] 63c 4th wall

[0261] 63d Third connection

[0262] 63e 4th connection

[0263] 63f Fixing protrusion

[0264] 63f1 expansion part

[0265] 63g anti-deviation protrusion

[0266] 63h Claw

[0267] 63y Insulating member second region

[0268] 63i Insulation member second opening

[0269] 63k Insulation member annular rib

[0270] 63z Insulation member third region

[0271] 80 outer cover

[0272] 80a Cover body

[0273] 80b Arm

[0274] 80c connecting protrusion

[0275] 80d root opening

[0276] 80e outer cover wall

[0277] 80f wall opening

[0278] 81 outer cover

[0279] 81a Cover body

[0280] 81b Arm

[0281] 81d root opening

[0282] 81e outer cover wall

[0283] 81f Wall opening

[0284] 81x Cover opening

[0285] 90 Welded connection

[0286] 102 sealing plate

[0287] 102x Press tabs

[0288] 161 conductive components

Claims

1. A secondary battery comprising: An electrode body, comprising a positive electrode plate and a negative electrode plate; a packaging body having an opening and accommodating the electrode body; a sealing plate for sealing the opening; a conductive member having an opening on the electrode body side, disposed on the electrode body side of the sealing plate via a first insulating member, and electrically connected to one of the positive electrode plate and the negative electrode plate; a deformable plate that seals the opening and deforms due to increased pressure within the package; a current collecting member electrically connecting the one electrode plate and the deformable plate; and a terminal electrically connected to the one electrode plate via the current collecting member, the deformable plate, and the conductive member; Inserting the terminal into the terminal mounting hole provided in the sealing plate, the terminal insertion hole provided in the first insulating member, and the terminal insertion hole provided in the conductive member, and connecting the terminal to the conductive member, At least one of the conductive member and the sealing plate has a pressing protrusion protruding toward the first insulating member at a portion facing the first insulating member. As the deformable plate deforms, the conductive path between the one electrode plate and the terminal is cut off. The first insulating member has a first groove portion at a portion disposed between the sealing plate and the conductive member and at a position farther from a terminal insertion hole provided in the first insulating member than a portion pressed by the pressing protrusion. The first insulating member has a second groove portion in a portion disposed between the sealing plate and the conductive member and at a position farther from a terminal insertion hole provided in the first insulating member than a portion pressed by the pressing protrusion. The first groove is provided on a surface of the first insulating member facing one of the sealing plate and the conductive member. The second groove is provided on a surface of the first insulating member facing the other of the sealing plate and the conductive member. The deformable plate is provided in the opening.

2. The secondary battery according to claim 1, wherein The end portion of the terminal on the electrode body side is passed through the terminal insertion hole of the conductive member, The terminal is fixed to the conductive member by riveting.

3. The secondary battery according to claim 1 or 2, wherein The second groove portion is provided at a position farther from a terminal insertion hole provided in the first insulating member than the first groove portion.

4. The secondary battery according to claim 1 or 2, wherein The first groove portion and the second groove portion are formed so that a portion of the first groove portion overlaps a portion of the second groove portion when the first insulating member is viewed in a plan view.

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