Angular secondary battery

Abstract

To provide a highly reliable square secondary battery with high volumetric energy density.SOLUTION: In a square secondary battery according to the present invention, an electrode body includes first and second electrode body elements including a positive plate and a negative plate, the first and second electrode body elements are each aligned in a short side direction of a sealing plate, a first tab group of one of the positive and negative electrode plates in the first electrode body element and a second tab group of one of the positive and negative electrode plates in the second electrode body element are electrically connected to a current collecting member, in the current collecting member, a connection portion with the first tab group and a connection portion with the second tab group are aligned in the short side direction of the sealing plate, and an electrolyte injection hole is disposed between the connection portion with the first tab group and the connection portion with the second tab group in the short side direction of the sealing plate.SELECTED DRAWING: Figure 16

Description

Technical Field

[0001] The present invention relates to a rectangular secondary battery.

Background Art

[0002] In driving power sources such as electric vehicles (EVs) and hybrid electric vehicles (HEVs, PHEVs), rectangular secondary batteries such as non-aqueous electrolyte secondary batteries are used.

[0003] In these rectangular secondary batteries, a battery case is constituted by a bottomed cylindrical rectangular exterior body having an opening and a sealing plate that seals the opening. Inside the battery case, an electrode body composed of a positive electrode plate, a negative electrode plate, and a separator is accommodated together with an electrolytic solution. A positive electrode terminal and a negative electrode terminal are attached to the sealing plate. The positive electrode terminal is electrically connected to the positive electrode plate via a positive electrode current collector, and the negative electrode terminal is electrically connected to the negative electrode plate via a negative electrode current collector.

[0004] The positive electrode plate includes a metal positive electrode core body and a positive electrode active material layer formed on the surface of the positive electrode core body. A positive electrode core body exposed portion where the positive electrode active material layer is not formed is formed in a part of the positive electrode core body. And a positive electrode current collector is connected to this positive electrode core body exposed portion. Further, the negative electrode plate includes a metal negative electrode core body and a negative electrode active material layer formed on the surface of the negative electrode core body. A negative electrode core body exposed portion where the negative electrode active material layer is not formed is formed in a part of the negative electrode core body. And a negative electrode current collector is connected to this negative electrode core body exposed portion.

[0005] For example, in Patent Document 1, a rectangular secondary battery using a wound electrode body having a positive electrode core body exposed portion wound around one end and a negative electrode core body exposed portion wound around the other end has been proposed. Also, in Patent Document 2, a rectangular secondary battery using an electrode body provided with a positive electrode core body exposed portion and a negative electrode core body exposed portion at one end has been proposed.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

[0007] Regarding in-vehicle secondary batteries, particularly rectangular secondary batteries used in EVs, PHEVs, etc., there is a demand for the development of rectangular secondary batteries with higher volume energy density and larger battery capacity. In the case of the rectangular secondary battery disclosed in the above Patent Document 1, in the battery case, left and right spaces for arranging the exposed portions of the wound positive electrode core body and the exposed portions of the wound negative electrode core body, and an upper space between the sealing plate and the wound electrode body are required, which makes it difficult to increase the volume energy density of the rectangular secondary battery. On the other hand, like the rectangular secondary battery disclosed in the above Patent Document 2, by arranging the exposed portion of the positive electrode core body and the exposed portion of the negative electrode core body on the sealing plate side, it becomes easier to obtain a rectangular secondary battery with high volume energy density.

[0008] The main object of the present invention is to provide a rectangular secondary battery with improved volume energy density and higher reliability. [Means for Solving the Problems]

[0009] A rectangular secondary battery according to an aspect of the present invention includes an electrode body including a positive electrode plate and a negative electrode plate, a rectangular exterior body having an opening and accommodating the electrode body, a sealing plate sealing the opening and having a longitudinal direction and a lateral direction, an electrolyte injection hole provided in the sealing plate, a tab provided on the positive electrode plate or the negative electrode plate, a tab group composed of a plurality of tabs, a terminal electrically connected to the tab group and attached to the sealing plate, a current collecting member electrically connected to the tab group and the terminal, and an insulating member disposed between the sealing plate and the current collecting member. The electrode body includes a first electrode body element including a positive electrode plate and a negative electrode plate, and a second electrode body element including a positive electrode plate and a negative electrode plate. The first electrode plate body element and the second electrode body element are arranged side by side in the lateral direction of the sealing plate. A first tab group of one of the positive electrode plate and the negative electrode plate in the first electrode body element and a second tab group of one of the positive electrode plate and the negative electrode plate in the second electrode body element are electrically connected to the current collecting member. In the current collecting member, a connection portion with the first tab group and a connection portion with the second tab group are arranged side by side in the lateral direction of the sealing plate. In the lateral direction of the sealing plate, an electrolyte injection hole is disposed between the connection portion with the first tab group and the connection portion with the second tab group.

Advantages of the Invention

[0010] According to the present invention, it is possible to provide a rectangular secondary battery with a higher volume energy density and higher reliability.

Brief Description of the Drawings

[0011]

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Figure 20

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Embodiments for Carrying Out the Invention

[0012] The configuration of the rectangular secondary battery 20 according to the embodiment will be described below. Note that the present invention is not limited to the following embodiments.

[0013] FIG. 1 is a perspective view of the rectangular secondary battery 20. FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1. As shown in FIGS. 1 and 2, the rectangular secondary battery 20 includes a battery case 100 composed of a bottomed rectangular tubular rectangular exterior body 1 having an opening and a sealing plate 2 that seals the opening of the rectangular exterior body 1. The rectangular exterior body 1 and the sealing plate 2 are each preferably made of metal, for example, preferably made of aluminum or an aluminum alloy. Inside the rectangular exterior body 1, a laminated electrode body 3 in which a positive electrode plate and a negative electrode plate are laminated via a separator is accommodated together with an electrolytic solution. An insulating sheet 14 made of resin is disposed between the electrode body 3 and the rectangular exterior body 1.

[0014] Positive electrode tabs 40 and negative electrode tabs 50 are provided at the end of the electrode body 3 on the side of the sealing plate 2. The positive electrode tab 40 is electrically connected to the positive electrode terminal 7 via a second positive electrode current collector 6b and a first positive electrode current collector 6a. The negative electrode tab 50 is electrically connected to the negative electrode terminal 9 via a second negative electrode current collector 8b and a first negative electrode current collector 8a. Here, the first positive electrode current collector 6a and the second positive electrode current collector 6b constitute the positive electrode current collecting member 6. Also, the first negative electrode current collector 8a and the second negative electrode current collector 8b constitute the negative electrode current collecting member 8. Note that the positive electrode current collecting member 6 can also be a single component. Also, the negative electrode current collecting member 8 can also be a single component.

[0015] The positive electrode terminal 7 is fixed to the sealing plate 2 via an external side insulating member 11 made of resin. The negative electrode terminal 9 is fixed to the sealing plate 2 via an external side insulating member 13 made of resin. The positive electrode terminal 7 is preferably made of metal, more preferably made of aluminum or an aluminum alloy. The negative electrode terminal 9 is preferably made of metal, more preferably made of copper or a copper alloy.

[0016] It is preferable that a current interruption mechanism 60 be provided in the conductive path between the positive electrode plate and the positive electrode terminal 7, which operates when the pressure inside the battery case 100 reaches a predetermined value or more and interrupts the conductive path between the positive electrode plate and the positive electrode terminal 7. Note that a current interruption mechanism may be provided in the conductive path between the negative electrode plate and the negative electrode terminal 9.

[0017] The sealing plate 2 is provided with a gas discharge valve 17 that breaks when the pressure inside the battery case 100 reaches a predetermined value or more and discharges the gas inside the battery case 100 to the outside of the battery case 100. Note that the operating pressure of the gas discharge valve 17 is set to a value larger than the operating pressure of the current interruption mechanism 60.

[0018] The sealing plate 2 is provided with an electrolyte injection hole 15. After injecting the electrolyte into the battery case 100 through the electrolyte injection hole 15, the electrolyte injection hole 15 is sealed with a sealing plug 16. It is preferable to use a blind rivet as the sealing plug 16.

[0019] Next, the manufacturing method of the rectangular secondary battery 20 and the details of each component will be described. [Fabrication of Positive Electrode Plate] A positive electrode slurry 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 is prepared. This 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, by drying this, NMP in the positive electrode slurry is removed, and a positive electrode active material composite layer is formed on the positive electrode core. Thereafter, the positive electrode active material composite layer is subjected to a compression treatment so as to have a predetermined thickness. The positive electrode plate thus obtained is cut into a predetermined shape.

[0020] FIG. 3 is a plan view of the positive electrode plate 4 manufactured by the method described above. As shown in FIG. 3, the positive electrode plate 4 has a main body portion in which positive electrode active material binder layers 4b are formed on both surfaces of a rectangular positive electrode core 4a. The positive electrode core 4a protrudes from the end sides of the main body portion, and this protruding positive electrode core 4a constitutes the positive electrode tab 40. Note that the positive electrode tab 40 may be a part of the positive electrode core 4a as shown in FIG. 3, or another member may be connected to the positive electrode core 4a to serve as the positive electrode tab 40. Further, it is preferable that a positive electrode protective layer 4d having an electric resistance larger than that of the positive electrode active material binder layer 4b is provided at a portion of the positive electrode tab 40 adjacent to the positive electrode active material binder layer 4b. [Fabrication of Negative Electrode Plate] 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 surfaces of a rectangular copper foil with a thickness of 8 μm serving as a negative electrode core. Then, by drying this, water in the negative electrode slurry is removed to form a negative electrode active material binder layer on the negative core. Thereafter, the negative electrode active material binder layer is subjected to a compression treatment so as to have a predetermined thickness. The negative electrode plate thus obtained is cut into a predetermined shape.

[0021] FIG. 4 is a plan view of the negative electrode plate 5 manufactured by the method described above. As shown in FIG. 4, the negative electrode plate 5 has a main body portion in which negative electrode active material binder layers 5b are formed on both surfaces of a rectangular negative electrode core 5a. The negative electrode core 5a protrudes from the end sides of the main body portion, and this protruding negative electrode core 5a constitutes the negative electrode tab 50. Note that the negative electrode tab 50 may be a part of the negative electrode core 5a as shown in FIG. 4, or another member may be connected to the negative electrode core 5a to serve as the negative electrode tab 50. [Fabrication of Electrode Body Element] Fifty positive electrode plates 4 and fifty-one negative electrode plates 5 are produced by the above-described method, and these are laminated via a square separator made of polyolefin to produce a laminated electrode body element (3a, 3b). As shown in FIG. 5, the laminated electrode body element (3a, 3b) is produced such that at one end, the positive electrode tabs 40 of the respective positive electrode plates 4 are laminated and the negative electrode tabs 50 of the respective negative electrode plates 5 are laminated. Separators are disposed on both outer surfaces of the electrode body element (3a, 3b), and the respective electrode plates and the separators can be fixed in a laminated state with a tape or the like. Alternatively, an adhesive layer may be provided on the separator so that the separator and the positive electrode plate 4 and the separator and the negative electrode plate 5 are adhered to each other, respectively.

[0022] Note that the size of the separator in plan view is preferably the same as that of the negative electrode plate 5 or larger than that of the negative electrode plate 5. A positive electrode plate 4 may be disposed between two separators, and after the peripheries of the separators are heat-sealed, the positive electrode plate 4 and the negative electrode plate 5 may be laminated. In producing the electrode body element (3a, 3b), a long separator may be used, and the positive electrode plate 4 and the negative electrode plate 5 may be laminated while folding the long separator into a ninety-nine fold shape. Further, a long separator may be used, and the positive electrode plate 4 and the negative electrode plate 5 may be laminated while winding the long separator.

[0023] [Attachment of Each Component to the Sealing Plate (Positive Electrode Side)] With reference to FIGS. 2 and 6 to 8, the method of attaching the positive electrode terminal 7 and the first positive electrode current collector 6a and the like to the sealing plate 2 and the configuration in the vicinity of the positive electrode terminal 7 will be described. FIG. 6 is a perspective view of the positive electrode terminal 7, the external side insulating member 11, the sealing plate 2, the first insulating member 10, and the conductive member 61 before assembly. FIG. 7 is a view showing the inner surface side of the battery of the sealing plate 2 after each component is attached. Note that in FIG. 7, the positive electrode tab 40 and the negative electrode tab 50 are not shown. FIG. 8A is a cross-sectional view in the vicinity of the positive electrode terminal 7 along line VIIIA-VIIIA in FIG. 7. FIG. 8B is a cross-sectional view in the vicinity of the positive electrode terminal 7 along line VIIIB-VIIIB in FIG. 7. FIG. 8C is a cross-sectional view in the vicinity of the positive electrode terminal 7 along line VIIIC-VIIIC in FIG. 7.

[0024] In the sealing plate 2, an external-side insulating member 11 is disposed on the battery outer surface side near the positive electrode terminal attachment hole 2a, and a first insulating member 10 and a conductive member 61 are disposed on the battery inner surface side near the positive electrode terminal attachment hole 2a. Next, an insertion portion 7b provided on one side of the flange portion 7a of the positive electrode terminal 7 is inserted into each of a first terminal insertion hole 11a of the external-side insulating member 11, a positive electrode terminal attachment hole 2a of the sealing plate 2, a second terminal insertion hole 10d of the first insulating member 10, and a third terminal insertion hole 61c of the conductive member 61. Then, the tip of the insertion portion 7b is caulked onto the conductive member 61. Thereby, the positive electrode terminal 7, the external-side insulating member 11, the sealing plate 2, the first insulating member 10, and the conductive member 61 are fixed. Note that when the insertion portion 7b of the positive electrode terminal 7 is caulked, a diameter-expanded portion having an outer diameter larger than the inner diameter of the third terminal insertion hole 61c of the conductive member 61 is formed on the tip side of the insertion portion 7b. It is preferable that 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. Further, the first insulating member 10 and the external-side insulating member 11 are preferably each made of resin.

[0025] Note that as shown in FIGS. 6 and 8, the first insulating member 10 has a first insulating member main body portion 10a disposed so as to face the sealing plate 2. A pair of first side walls 10b are provided at both ends of the first insulating member main body portion 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 main body portion 10a in the short-side direction of the sealing plate 2. A second terminal insertion hole 10d is provided in the first insulating member main body portion 10a. A first connection portion 10e is provided on the outer surface side of the second side wall 10c. The first connection portion 10e is preferably provided at the center of the second side wall 10c in the longitudinal direction of the sealing plate 2. Further, a second connection portion 10f is provided on the outer surface side of the second side wall 10c. The second connection portion 10f is preferably provided at the end of the second side wall 10c in the longitudinal direction of the sealing plate 2. A first groove portion 10x is provided on the surface of the first insulating member main body portion 10a on the sealing plate 2 side, and a second groove portion 10y is provided on the surface of the first insulating member main body portion 10a on the conductive member 61 side. The second groove portion 10y is located on the outer peripheral side of the first groove portion 10x. A recess 10g is provided at the corner on the surface of the first insulating member main body portion 10a on the sealing plate 2 side.

[0026] As shown in FIGS. 6 and 8, the conductive member 61 has a conductive member base portion 61a arranged to face the first insulating member main body portion 10a, and a tubular portion 61b extending from the edge portion of the conductive member base portion 61a toward the electrode body 3. The cross-sectional shape parallel to the sealing plate 2 of the tubular portion 61b may be circular or angular. A flange portion 61d is provided at the end portion of the tubular portion 61b on the side of the electrode body 3. A conductive member opening 61f is provided at the end portion of the tubular portion 61b on the side of the electrode body 3. A pressing protrusion 61e is provided on the surface of the conductive member base portion 61a facing the first insulating member 10. The pressing protrusion 61e presses the first insulating member 10 toward the sealing plate 2 side. Preferably, the pressing protrusion 61e is formed at the edge portion of the third terminal insertion hole 61c or in its vicinity.

[0027] Next, the deformation plate 62 is arranged so as to close the conductive member opening 61f of the conductive member 61, and the peripheral edge of the deformation plate 62 is welded to the conductive member 61 by laser welding or the like. Thereby, the conductive member opening 61f of the conductive member 61 is sealed by the deformation plate 62. Preferably, the conductive member 61 and the deformation plate 62 are each made of metal, and more preferably aluminum or an aluminum alloy.

[0028] FIG. 9 is a perspective view of the deformation plate 62. In FIG. 9, the upper side is the side of the electrode body 3, and the lower side is the side of the sealing plate 2. As shown in FIG. 9, a stepped protrusion 62a protruding toward the electrode body 3 side is provided at the central portion of the deformation plate 62. This stepped protrusion 62a includes a first protrusion portion 62a1 and a second protrusion portion 62a2 having an outer diameter smaller than that of the first protrusion portion 62a1 and protruding from the first protrusion portion 62a1 toward the electrode body 3 side. The deformation plate 62 has an annular rib 62b protruding toward the electrode body 3 side at its outer peripheral edge. An annular thin-walled portion 62c is provided on the surface of the deformation plate 62 on the side of the electrode body 3. The deformation plate 62 may have any shape that can seal the conductive member opening 61f of the conductive member 61.

[0029] Next, a method for fixing the second insulating member 63 and the first positive current collector 6a will be described with reference to FIG. 10. In FIG. 10, the surface of the rectangular secondary battery 20 that is disposed on the side of the electrode body 3 is positioned upward, and the surface that is disposed on the side of the sealing plate 2 is positioned downward.

[0030] As shown in FIG. 10A, the first positive current collector 6a has a connection hole 6c. The edge of this connection hole 6c is welded to the deformation plate 62. In the first positive current collector 6a, four fixing holes 6d are provided around the connection hole 6c. Note that the number of fixing holes 6d may be one, but preferably two or more are provided. In the first positive current collector 6a, a misalignment prevention hole 6e is provided around the connection hole 6c. The misalignment prevention hole 6e may be one, but preferably at least two are provided. The misalignment prevention hole 6e is preferably disposed between the fixing holes 6d and the fixing holes 6d. Further, the fixing hole 6d preferably has a small diameter portion 6d1 and a large diameter portion 6d2 having an inner diameter larger than that of the small diameter portion 6d1. The large diameter portion 6d2 is preferably disposed closer to the electrode body 3 side than the small diameter portion 6d1.

[0031] As shown in FIGS. 8 and 10A, the second insulating member 63 has an insulating member first region 63x arranged to face the deformed plate 62, an insulating member second region 63y arranged to face the sealing plate 2, and an insulating member third region 63z connecting the insulating member first region 63x and the insulating member second region 63y. An insulating member first opening 63a is provided at the center of the insulating member first region 63x. In the insulating member first region 63x, a third wall portion 63b is provided at an end portion of the sealing plate 2 in the longitudinal direction. A third connection portion 63d is provided on the third wall portion 63b. Also, in the insulating member first region 63x, fourth wall portions 63c are provided at both end portions of the sealing plate 2 in the short transverse direction. A fourth connection portion 63e is provided on the fourth wall portion 63c. Further, four fixing protrusions 63f are provided on the surface of the insulating member first region 63x on the side of the electrode body 3. Also, two displacement preventing protrusions 63g are provided. Four claw portions 63h are provided on the surface of the insulating member first region 63x on the side of the sealing plate 2. The insulating member second region 63y is arranged at a position closer to the sealing plate 2 than the insulating member first region 63x. In the insulating member second region 63y, an insulating member second opening 63i is provided at a position facing the electrolyte injection hole 15 provided in the sealing plate 2. An insulating member annular rib 63k extending toward the electrode body 3 side is provided at the edge portion of the insulating member second opening 63i.

[0032] As shown in FIG. 10B, the first positive electrode current collector 6a is arranged on the second insulating member 63 such that the fixing protrusion 63f of the second insulating member 63 is arranged in the fixing hole 6d of the first positive electrode current collector 6a and the displacement preventing protrusion 63g of the second insulating member 63 is arranged in the displacement preventing hole 6e of the first positive electrode current collector 6a. Then, the tip portion of the fixing protrusion 63f of the second insulating member 63 is deformed by caulking with heat or the like. As a result, as shown in FIGS. 8C and 10C, a diameter-expanded portion 63f1 is formed at the tip portion of the fixing protrusion 63f of the second insulating member 63, and the second insulating member 63 and the first positive electrode current collector 6a are fixed.

[0033] Note that, as shown in FIG. 8C, it is preferable that the diameter-expanded portion 63f1 formed at the tip portion of the fixing protrusion 63f of the second insulating member 63 is arranged within the large-diameter portion 6d2 of the fixing hole 6d.

[0034] The displacement prevention protrusion 63g of the second insulating member 63 is not thermally caulked like the fixing protrusion 63f.

[0035] In addition, it is preferable that the outer diameter of the fixing protrusion 63f is larger than the outer diameter of the displacement prevention protrusion 63g. Also, it is preferable that the inner diameter of the small-diameter portion 6d1 of the fixing hole 6d of the first positive electrode current collector 6a is larger than the inner diameter of the displacement prevention hole 6e of the first positive electrode current collector 6a.

[0036] Next, as shown in FIGS. 8A to 8C, the second insulating member 63 to which the first positive electrode current collector 6a is fixed is connected to the first insulating member 10 and the conductive member 61.

[0037] As shown in FIG. 8B, the fourth connection portion 63e of the second insulating member 63 is connected to the first connection portion 10e of the first insulating member 10. Also, as shown in FIG. 8C, the claw portion 63h of the second insulating member 63 is connected to the flange portion 61d of the conductive member 61. Thereby, the second insulating member 63 is connected to each of the first insulating member 10 and the conductive member 61. Note that the second insulating member 63 does not necessarily need to be connected to both the first insulating member 10 and the conductive member 61. However, the second insulating member 63 is preferably connected to at least one of the first insulating member 10 and the conductive member 61. Thereby, even when a strong impact or vibration is applied to the rectangular secondary battery 20, it is possible to suppress a load from being applied to the vulnerable portion of the first positive electrode current collector 6a. Therefore, damage or breakage of the vulnerable portion of the first positive electrode current collector 6a can be suppressed.

[0038] The deformed plate 62 is welded and connected to the first positive electrode current collector 6a. FIG. 11 is an enlarged view of the vicinity of the connection portion between the deformed plate 62 and the first positive electrode current collector 6a in FIG. 8A. As shown in FIG. 11, the second protruding portion 62a2 of the deformed plate 62 is disposed in the connection hole 6c of the first positive electrode current collector 6a. Then, the second protruding portion 62a2 of the deformed plate 62 and the edge portion of the connection hole 6c of the first positive electrode current collector 6a are welded and connected by laser welding or the like. Note that the connection portion between the deformed plate 62 and the first positive electrode current collector 6a is formed at a position corresponding to the first opening 63a of the insulating member of the second insulating member 63.

[0039] In the first positive electrode current collector 6a, a thin portion 6f is provided around the connection hole 6c. An annular notch 6g is provided in the thin portion 6f so as to surround the connection hole 6c. An annular connection rib 6h is formed at the edge of the connection hole 6c. This connection rib 6h is welded and connected to the deformation plate 62. Note that the first positive electrode current collector 6a and the deformation plate 62 may be welded and connected annularly over the entire circumference of the connection hole 6c, or there may be a portion that is not welded annularly. Further, the first positive electrode current collector 6a and the deformation plate 62 may be welded at a plurality of spaced locations at the edge of the connection hole 6c.

[0040] Here, the operation of the current interruption mechanism 60 will be described. When the pressure inside the battery case 100 rises, the central portion of the deformation plate 62 deforms so as to move toward the sealing plate 2 side. Then, when the pressure inside the battery case 100 becomes equal to or higher than a predetermined value, along with the deformation of the deformation plate 62, the notch 6g provided in the thin portion 6f of the first positive electrode current collector 6a breaks. As a result, the current conduction path from the positive electrode plate 4 to the positive electrode terminal 7 is cut off. In this way, the current interruption mechanism 60 includes the first positive electrode current collector 6a, the deformation plate 62, and the conductive member 61. When the rectangular secondary battery 20 is in an overcharged state and the pressure inside the battery case 100 rises, the current interruption mechanism 60 operates, and the current conduction path from the positive electrode plate 4 to the positive electrode terminal 7 is cut off, thereby preventing further progress of overcharging. Note that the operating pressure at which the current interruption mechanism 60 operates can be determined as appropriate.

[0041] Before performing the welding connection between the deformation plate 62 and the first positive electrode current collector 6a, by sending gas to the inner side of the conductive member 61 through the terminal through hole 7c formed in the positive electrode terminal 7, a leak inspection of the welded portion can be performed on the conductive member 61 and the deformation plate 62. The terminal through hole 7c is sealed by a terminal sealing member 7x. Note that the terminal sealing member 7x preferably includes a metal member 7y and a rubber member 7z.

[0042] FIG. 12 is a perspective view of the sealing plate 2 to which the first insulating member 10, the conductive member 61, the deformed plate 62, the second insulating member 63, and the first positive current collector 6a are attached. As shown in FIG. 12, a third connection portion 63d is provided at the longitudinal end of the sealing plate 2 in the second insulating member 63. Second connection portions 10f are provided at both ends in the short direction of the sealing plate 2 in the first insulating member 10. [Attachment of each component to the sealing plate (negative electrode side)] With reference to FIGS. 2 and 13, a method of attaching the negative electrode terminal 9 and the first negative current collector 8a to the sealing plate 2 will be described. An external insulating member 13 is disposed on the outer surface side of the battery near the negative electrode terminal attachment hole 2b provided in the sealing plate 2, and an internal insulating member 12 and the first negative current collector 8a are disposed on the inner surface side of the battery near the negative electrode terminal attachment hole 2b. Next, the negative electrode terminal 9 is inserted into each of the through hole of the external insulating member 13, the negative electrode terminal attachment hole 2b of the sealing plate 2, the through hole of the internal insulating member 12, and the through hole of the first negative current collector 8a. Then, the tip of the negative electrode terminal 9 is caulked onto the first negative current collector 8a. Thereby, the external insulating member 13, the sealing plate 2, the internal insulating member 12, and the first negative current collector 8a are fixed. It is preferable that the caulked portion of the negative electrode terminal 9 and the first negative current collector 8a are welded and connected by laser welding or the like. Further, it is preferable that the internal insulating member 12 and the external insulating member 13 are each made of resin. [Connection between current collector and tab] FIG. 14 is a diagram showing a method of connecting the positive electrode tab 40 to the second positive current collector 6b and a method of connecting the negative electrode tab 50 to the second negative current collector 8b. Two electrode body elements are manufactured by the above-described method, and are respectively referred to as a first electrode body element 3a and a second electrode body element 3b. Note that the first electrode body element 3a and the second electrode body element 3b may have exactly the same configuration or different configurations. Here, a plurality of positive electrode tabs 40 of the first electrode body element 3a constitute a first positive electrode tab group 40a. A plurality of negative electrode tabs 50 of the first electrode body element 3a constitute a first negative electrode tab group 50a. A plurality of positive electrode tabs 40 of the second electrode body element 3b constitute a second positive electrode tab group 40b. A plurality of negative electrode tabs 50 of the second electrode body element 3b constitute a second negative electrode tab group 50b.

[0043] Between the first electrode body element 3a and the second electrode body element 3b, a second positive current collector 6b and a second negative current collector 8b are arranged. Then, a first positive tab group 40a composed of a plurality of laminated positive tabs 40 protruding from the first electrode body element 3a is arranged on the second positive current collector 6b, and a first negative tab group 50a composed of a plurality of laminated negative tabs 50 protruding from the first electrode body element 3a is arranged on the second negative current collector 8b. Also, a second positive tab group 40b composed of a plurality of laminated positive tabs 40 protruding from the second electrode body element 3b is arranged on the second positive current collector 6b, and a second negative tab group 50b composed of a plurality of laminated negative tabs 50 protruding from the second electrode body element 3b is arranged on the second negative current collector 8b. The first positive tab group 40a and the second positive tab group 40b are each welded and connected to the second positive current collector 6b to form a welded connection portion 90. The first negative tab group 50a and the second negative tab group 50b are each welded and connected to the second negative current collector 8b to form a welded connection portion 90. The welding connection can be performed as follows.

[0044] The tabs (the first positive tab group 40a, the second positive tab group 40b, the first negative tab group 50a, the second negative tab group 50b) laminated by a welding jig from above and below and the current collectors (the second positive current collector 6b, the second negative current collector 8b) are sandwiched and welded. Here, the welding method is preferably ultrasonic welding or resistance welding. Note that the pair of welding jigs are a pair of resistance welding electrodes in the case of resistance welding, and a horn and an anvil in the case of ultrasonic welding. Note that the connection between the tabs (the first positive tab group 40a, the second positive tab group 40b, the first negative tab group 50a, the second negative tab group 50b) and the current collectors (the second positive current collector 6b, the second negative current collector 8b) can also be connected by laser welding.

[0045] As shown in Fig. 14, the second positive current collector 6b has a current collector first region 6b1 and a current collector second region 6b2. A positive tab 40 is connected to the current collector first region 6b1. A current collector second opening 6z is provided in the current collector first region 6b1. The current collector first region 6b1 and the current collector second region 6b2 are connected by a current collector third region 6b3. After connecting the second positive current collector 6b to the first positive current collector 6a, the current collector second opening 6z is disposed at a position corresponding to the electrolyte injection hole 15 provided in the sealing plate 2. A current collector first opening 6y is provided in the current collector second region 6b2. And a current collector first recess 6m is provided around the current collector first opening 6y. Also, target holes 6k are provided on both sides of the current collector first opening 6y in the short side direction of the sealing plate 2.

[0046] As shown in Fig. 14, the second negative current collector 8b has a current collector first region 8b1 and a current collector second region 8b2. A negative tab 50 is connected to the current collector first region 8b1. A current collector first opening 8y is provided in the current collector second region 8b2. And a current collector first recess 8f is provided around the current collector first opening 8y. Also, target holes 8e are provided on both sides of the current collector first opening 8y in the short side direction of the sealing plate 2. [Connection between the first positive current collector and the second positive current collector] As shown in Figs. 2, 7, 8, etc., the current collector projection 6x of the first positive current collector 6a is positioned within the current collector first opening 6y of the second positive current collector 6b, and the second positive current collector 6b is disposed on the second insulating member 63. Then, the edge of the current collector projection 6x of the first positive current collector 6a and the current collector first opening 6y of the second positive current collector 6b are welded by irradiation with an energy beam such as a laser. Thereby, the first positive current collector 6a and the second positive current collector 6b are connected. Note that it is preferable that the first positive current collector 6a and the second positive current collector 6b are welded and connected in the current collector first recess 6m.

[0047] As shown in FIGS. 2 and 8, in the 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. With such a configuration, the space occupied by the current collecting portion can be made smaller, and a rectangular secondary battery with a higher volume energy density can be obtained.

[0048] When welding the first positive current collector 6a and the second positive current collector 6b by irradiating with an energy beam such as a laser, it is preferable to use the target hole 6k as a target for image correction.

[0049] As shown in FIG. 8A, on the surface of the first positive current collector 6a facing the second insulating member 63 and on the back side of the current collector protrusion 6x, a second current collector recess 6w is formed. This is preferable because it facilitates the formation of a larger welded connection portion between the first positive current collector 6a and the second positive current collector 6b. Further, since the second current collector recess 6w is formed, it is possible to prevent the second insulating member 63 from being damaged by the heat during welding when the first positive current collector 6a and the second positive current collector 6b are welded and connected.

[0050] [Connection between the first negative current collector and the second negative current collector] As shown in FIG. 13, the second negative current collector 8b has a first current collector region 8b1 and a second current collector region 8b2. A negative 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 by a third current collector region 8b3.

[0051] As shown in FIG. 13, the current collector protrusion 8x of the first negative current collector 8a is positioned within the first current collector opening 8y of the second negative current collector 8b, and the second negative current collector 8b is disposed on the inner side insulating member 12. Then, the edge of the current collector protrusion 8x of the first negative current collector 8a and the first current collector opening 8y of the second negative current collector 8b are welded by irradiating with an energy beam such as a laser. Thereby, the first negative current collector 8a and the second negative current collector 8b are connected. In the current collector first recess 8f, it is preferable that the first negative current collector 8a and the second negative current collector 8b are welded and connected. The second negative current collector 8b is provided with a target hole 8e in the same manner as the second positive current collector 6b. In the direction perpendicular to the sealing plate 2, the distance between the sealing plate 2 and the first current collector region 8b1 is smaller than the distance between the sealing plate 2 and the second current collector region 8b2. Note that the second negative current collector 8b can be connected to the negative terminal 9 without using the first negative current collector 8a.

[0052] As shown in FIG. 13, on the surface of the first negative current collector 8a facing the inner side insulating member 12 and on the back side of the current collector protrusion 8x, a current collector second recess 8w is formed. This is preferable because it facilitates the formation of a larger welded connection portion between the first negative current collector 8a and the second negative current collector 8b. Further, since the current collector second recess 8w is formed, it is possible to prevent the inner side insulating member 12 from being damaged by the heat during welding when the first negative current collector 8a and the second negative current collector 8b are welded and connected.

[0053] Note that the current collector protrusions 6x and 8x preferably each have a non-circular shape in plan view, and are preferably square, elliptical, or track-shaped. [Bending of tabs and fabrication of electrode bodies] FIGS. 15A to 15C are diagrams showing a step of disposing the second positive current collector 6b to which the first positive tab group 40a of the first electrode body element 3a and the second positive tab group 40b of the second electrode body element 3b are connected on the sealing plate 2 via the second insulating member 63.

[0054] As shown in FIG. 15A, a second insulating member 63 is disposed on the inner surface side of the sealing plate 2 in the battery. Here, the second insulating member 63 has a base portion 630a (corresponding to the second region 63y of the insulating member described above). In the base portion 630a, a first wall portion 630b extending in a direction away from the sealing plate 2 is provided at one end in the short side direction of the sealing plate 2, and a second wall portion 630c extending in a direction away from the sealing plate 2 is provided at the other end in the short side direction of the sealing plate 2. In the base portion 630a, a second insulating member opening 63i is provided at a position facing the electrolyte injection hole 15 of the sealing plate 2. An insulating member annular rib 63k extending in a direction away from the sealing plate 2 is provided around the second insulating member opening 63i.

[0055] Next, as shown in FIG. 15B, the second positive electrode current collector 6b is disposed on the sealing plate 2 via the second insulating member 63. The base portion 630a of the second insulating member 63 is disposed between the second positive electrode current collector 6b and the sealing plate 2. Further, the first wall portion 630b and the second wall portion 630c each project in a direction away from the sealing plate 2 from the surface of the second positive electrode current collector 6b to which the first positive electrode tab group 40a and the second positive electrode tab group 40b are connected. After the state of FIG. 15B is obtained, the second positive electrode current collector 6b is welded and connected to the first positive electrode current collector 6a.

[0056] Next, as shown in FIG. 15C, the first positive electrode tab group 40a and the second positive electrode tab group 40b are bent so as to bundle the first electrode body element 3a and the second electrode body element 3b together. Here, the first positive electrode tab group 40a and the second positive electrode tab group 40b are bent in different directions.

[0057] The first positive electrode tab group 40a is connected to a region disposed along the sealing plate 2 in the second positive electrode current collector 6b. The tip of the first positive electrode tab group 40a is located on the center side in the short side direction of the sealing plate 2. The first positive electrode tab group 40a bends near the first wall portion 630b and is connected to each positive electrode plate. Then, the outer surface of the first positive electrode tab group 40a on the first wall portion 630b side is in contact with the inner surface of the first wall portion 630b (the side surface on the center side in the short side direction of the sealing plate 2).

[0058] The second positive tab group 40b is connected to a region disposed along the sealing plate 2 in the second positive current collector 6b. The tip of the second positive tab group 40b is located on the center side in the short side direction of the sealing plate 2. The second positive tab group 40b bends near the second wall portion 630c and is connected to each positive electrode plate. And, the outer surface on the second wall portion 630c side in the second positive tab group 40b is in contact with the inner surface of the second wall portion 630c (the side surface on the center side in the short side direction of the sealing plate 2).

[0059] The outer surface on the first wall portion 630b side in the first positive tab group 40a is in contact with the inner surface of the first wall portion 630b, and the outer surface on the second wall portion 630c side in the second positive tab group 40b is in contact with the inner surface of the second wall portion 630c. With such a configuration, the curved first positive tab group 40a to the second positive tab group 40b are curved into the intended shape. Therefore, it is possible to more effectively prevent the curved first positive tab group 40a to the second positive tab group 40b from protruding outward in the short side direction of the sealing plate 2, curving into an unintended shape, or bending. For example, if the first positive tab group 40a to the second positive tab group 40b protrude outward in the short side direction of the sealing plate 2, curve into an unintended shape, or bend, the positive tab 40 may be damaged or injured, or may cause an unintended short circuit. Further, the first positive tab group 40a to the second positive tab group 40b protruding outward in the short side direction of the sealing plate 2 may reduce the insertability when inserting the electrode body 3 into the rectangular exterior body 1.

[0060] Note that it is preferable that the negative electrode side has the same configuration as the positive electrode side. It is preferable to provide a base portion disposed between the sealing plate 2 and the second negative current collector 8b on the inner side insulating member 12, and a wall portion provided on the base portion and extending in a direction away from the sealing plate 2. And, it is preferable to bring the first negative tab group 50a and the second negative tab group 50b into contact with the inner surface of the wall portion, respectively.

[0061] It is preferable to bundle the first electrode body element 3a and the second electrode body element 3b together with a tape or the like. Alternatively, it is preferable to arrange the first electrode body element 3a and the second electrode body element 3b in an insulating sheet 14 formed in a box shape or a bag shape and bundle them together. Alternatively, it is preferable to fix the first electrode body element 3a and the second electrode body element 3b by adhesion. [Attachment of Cover Portion] After connecting the second positive current collector 6b to the first positive current collector 6a and connecting the second negative current collector 8b to the first negative current collector 8a, before bundling the first electrode body element 3a and the second electrode body element 3b together, it is preferable to connect a resin cover portion 80 to the first insulating member 10 and the second insulating member 63. Note that the cover portion 80 is not an essential component and can be omitted. As shown in FIG. 2, in the rectangular secondary battery 20, the cover portion 80 is disposed between the first positive current collector 6a and the electrode body 3. Note that the cover portion 80 is connected to the second connection portion 10f of the first insulating member 10 and the third connection portion 63d of the second insulating member 63. Note that the cover portion 80 is preferably connected to at least one of the first insulating member 10 and the second insulating member 63. [Regarding the rectangular secondary battery 20] FIG. 16 is a cross-sectional view of the vicinity of the sealing plate 2 in the XVI-XVI cross-section in FIG. 1. The first positive tab group 40a and the second positive tab group 40b are each in a curved state and are connected to a portion of the second positive current collector 6b disposed along the sealing plate 2. Due to such a configuration, the rectangular secondary battery 20 becomes a rectangular secondary battery with a higher volume energy density.

[0062] The second insulating member 63 as an insulating member has a base portion 630a disposed between the sealing plate 2 and the second positive current collector 6b as a positive current collecting member, and a first wall portion 630b protruding from one end of the base portion 630a in the short side direction of the sealing plate 2 toward the electrode body 3. The first wall portion 630b is disposed between the first positive tab group 40a and the side surface (the left side surface in FIG. 16) of the rectangular exterior body 1 on the side close to the first positive tab group 40a. Therefore, the structure is such that the first positive tab group 40a and the rectangular exterior body 1 are less likely to come into direct contact. Thus, a more reliable rectangular secondary battery is obtained.

[0063] The base portion 630a of the second insulating member 63 as the insulating member has a second wall portion 630c that protrudes from the other end portion in the short side direction of the sealing plate 2 toward the electrode body 3. And the second wall portion 630c is disposed between the second positive tab group 40b and the side surface (the left side surface in FIG. 16) of the rectangular exterior body 1 on the side close to the second positive tab group 40b. For this reason, the structure is such that the second positive tab group 40b and the rectangular exterior body 1 are difficult to come into direct contact. Thus, a rectangular secondary battery with higher reliability is obtained.

[0064] The outer surface of the first positive tab group 40a on the side of the first wall portion 630b is in contact with the inner surface of the first wall portion 630b. With such a configuration, it is possible to suppress the first positive tab group 40a from having an unintended shape. For this reason, it is possible to more effectively prevent the positive tabs 40 constituting the first positive tab group 40a from being damaged or injured. Alternatively, it is possible to more effectively prevent an unexpected short circuit between the positive and negative electrodes from occurring.

[0065] The outer surface of the second positive tab group 40b on the side of the second wall portion 630c is in contact with the inner surface of the second wall portion 630c. With such a configuration, it is possible to suppress the second positive tab group 40b from having an unintended shape. For this reason, it is possible to more effectively prevent the positive tabs 40 constituting the second positive tab group 40b from being damaged or injured. Alternatively, it is possible to more effectively prevent an unexpected short circuit between the positive and negative electrodes from occurring.

[0066] As shown in FIG. 16, it is preferable that the end portion of the insulating sheet 14 on the side of the sealing plate 2 is located on the sealing plate 2 side rather than the lower end of the first wall portion 630b. That is, it is preferable that the insulating sheet 14 extends from between the rectangular exterior body 1 and the electrode body 3 to between the rectangular exterior body 1 and the first wall portion 630b. Further, it is preferable that the end portion of the insulating sheet 14 on the side of the sealing plate 2 is located on the sealing plate 2 side rather than the lower end of the second wall portion 630c. That is, it is preferable that the insulating sheet 14 extends from between the rectangular exterior body 1 and the electrode body 3 to between the rectangular exterior body 1 and the second wall portion 630c. Thereby, the insulating sheet 14 and the first wall portion 630b overlap in the short side direction of the sealing plate 2, and the insulating sheet 14 and the second wall portion 630c overlap in the short side direction of the sealing plate 2. For this reason, it is possible to more reliably prevent the first positive tab group 40a to the second positive tab group 40b from directly contacting the rectangular exterior body 1. Note that, in the short side direction of the sealing plate 2, the thickness of the first wall portion 630b and the thickness of the second wall portion 630c are preferably each larger than the thickness of the insulating sheet 14.

[0067] As shown in FIG. 16, in the short side direction of the sealing plate 2, the distance between the rectangular exterior body 1 and the first wall portion 630b is larger than the distance between the rectangular exterior body 1 and the electrode body 3. Also, in the short side direction of the sealing plate 2, the distance between the rectangular exterior body 1 and the second wall portion 630c is larger than the distance between the rectangular exterior body 1 and the electrode body 3. With such a configuration, it is possible to more reliably prevent the first positive tab group 40a to the second positive tab group 40b from directly contacting the rectangular exterior body 1.

[0068] Further, the positive electrode current collecting member 6 is composed of a first positive electrode current collector 6a and a second positive electrode current collector 6b, and the first positive tab group 40a and the second positive tab group 40b are connected to the second positive electrode current collector. For this reason, a rectangular secondary battery having a higher volume energy density can be manufactured by a simpler method.

[0069] As shown in Fig. 17, a first recess 2c is provided on the surface of the sealing plate 2 on the side of the electrode body 3. Further, as shown in Fig. 6, a first protrusion 70 is provided at a portion of the second insulating member 63 facing the sealing plate 2. In the rectangular secondary battery 20, the first protrusion 70 is disposed in the first recess 2c. Thereby, in a plane parallel to the sealing plate 2, displacement of the second insulating member 63 relative to the sealing plate 2 can be suppressed significantly.

[0070] Note that the shapes of the first protrusion 70 and the first recess 2c are not particularly limited. When viewed from a direction perpendicular to the sealing plate 2, the shape of the first protrusion 70 is preferably circular. Also, when viewed from a direction perpendicular to the sealing plate 2, the shape of the first recess 2c is preferably circular, and more preferably oval.

[0071] The difference between the width of the first recess 2c and the width of the first protrusion 70 in the short side direction of the sealing plate 2 is preferably 5 mm or less, more preferably 3 mm or less, and even more preferably 1 mm or less.

[0072] When viewed from a direction perpendicular to the sealing plate 2, the width of the first recess 2c in the longitudinal direction of the sealing plate 2 is preferably larger than the width of the first recess 2c in the short side direction of the sealing plate 2.

[0073] The difference between the width of the first recess 2c and the width of the first protrusion 70 in the longitudinal direction of the sealing plate 2 is preferably larger than the difference between the width of the first recess 2c and the width of the first protrusion 70 in the short side direction of the sealing plate 2. With such a configuration, displacement of the second insulating member 63 relative to the sealing plate 2 in the short side direction of the sealing plate 2 can be suppressed, and the second insulating member 63 can be easily assembled to the sealing plate 2.

[0074] Note that the shapes of the first protrusion 70 and the first recess 2c in plan view are preferably linear or dot-like, and more preferably dot-like.

[0075] In the longitudinal direction of the sealing plate 2, the first recess 2c is preferably disposed between the gas discharge valve 17 and the electrolyte injection hole 15. In the longitudinal direction of the sealing plate 2, the second insulating member 63 is preferably connected to other components on the positive electrode terminal 7 side of the electrolyte injection hole 15. With such a configuration, since the second insulating member 63 is directly or indirectly connected to the sealing plate 2 at a plurality of more distant locations, the displacement of the second insulating member 63 with respect to the sealing plate 2 can be more effectively suppressed in a plane parallel to the sealing plate 2. In the rectangular secondary battery 20, the second insulating member 63 is connected to the first insulating member 10 fixed to the sealing plate 2. Further, the second insulating member 63 is fixed to the conductive member 61 fixed to the sealing plate 2 via the first insulating member 10 and the positive electrode terminal 7.

[0076] In the short side direction of the sealing plate 2, the first recess 2c is preferably offset toward the end side of the sealing plate 2 from the center of the sealing plate 2. With such a configuration, even when the first recess 2c is provided in the sealing plate 2, it is possible to suppress a decrease in the strength of the sealing plate 2. Therefore, the sealing plate 2 is less likely to be deformed.

[0077] In the rectangular secondary battery 20, the second insulating member 63 is disposed between the deformation plate 62 and the first positive electrode current collector 6a, and has an insulating member first region 63x fixed to the first positive electrode current collector 6a and an insulating member second region 63y disposed on the sealing plate 2. And a first convex portion is formed in the insulating member second region of the second insulating member 63. For this reason, it is possible to suppress a load from being applied to the vulnerable part of the current interruption mechanism 60 due to the displacement of the second insulating member 63 with respect to the sealing plate 2. Alternatively, it is possible to prevent damage to the first positive electrode tab group 40a to the second positive electrode tab group 40b.

[0078] Note that the depth of the first recess 2c is preferably 30% to 70% with respect to the thickness of the sealing plate 2 around the first recess 2c. In the short side direction of the sealing plate 2, the distance from the center of the sealing plate 2 to the first recess 2c is preferably 1 / 10 or more, more preferably 1 / 8 or more, and still more preferably 1 / 5 or more with respect to the length of the sealing plate 2.

[0079] As shown in FIG. 17, a second recess 2d is provided on the surface of the sealing plate 2 on the side of the electrode body 3. Further, as shown in FIG. 6, a second protrusion 71 is provided at a portion of the first insulating member 10 facing the sealing plate 2. In the rectangular secondary battery 20, the second protrusion 71 is disposed in the second recess 2d. Thereby, in the plane parallel to the sealing plate 2, it is possible to suppress the first insulating member 10 from being largely displaced with respect to the sealing plate 2.

[0080] Note that the shapes of the second protrusion 71 and the second recess 2d are not particularly limited. When viewed from a direction perpendicular to the sealing plate 2, the shape of the second protrusion 71 is preferably circular. Further, when viewed from a direction perpendicular to the sealing plate 2, the shape of the second recess 2d is preferably circular, and more preferably oval.

[0081] The difference between the width of the second recess 2d and the width of the second protrusion 71 in the short side direction of the sealing plate 2 is preferably 5 mm or less, more preferably 3 mm or less, and still more preferably 1 mm or less.

[0082] Note that the shapes of the second protrusion 71 and the second recess 2d in plan view are preferably linear or dot-like, and more preferably dot-like.

[0083] The second insulating member 63 disposed between the deformation plate 62 and the first positive electrode current collector 6a and fixed to the first positive electrode current collector 6a is preferably connected to the first insulating member 10. In such a case, by disposing the second protrusion 71 provided on the first insulating member 10 in the second recess 2d provided on the sealing plate 2 and suppressing the first insulating member 10 from being largely displaced with respect to the sealing plate 2, it is possible to more effectively suppress a load from being applied to the vulnerable portion of the current interruption mechanism 60.

[0084] In the longitudinal direction of the sealing plate 2, the second recess 2d is preferably disposed outside the positive electrode terminal attachment hole 2a. With such a configuration, in the longitudinal direction of the sealing plate 2, it is possible to suppress a decrease in the strength of the sealing plate 2 as compared with the case where the second recess 2d is provided inside the positive electrode terminal attachment hole 2a. Further, in the short direction of the sealing plate 2, the second recess 2d is preferably disposed closer to the end side of the sealing plate 2 than the center of the sealing plate 2. When the first recess 2c is formed in the sealing plate 2, in the short direction of the sealing plate 2, the first recess 2c is preferably formed on one side of the center of the sealing plate 2, and the second recess 2d is preferably formed on the other side of the center of the sealing plate 2.

[0085] Note that the depth of the second recess 2d is preferably 30% to 70% with respect to the thickness of the sealing plate 2 around the second recess 2d. Further, in the short direction of the sealing plate 2, the distance from the center of the sealing plate 2 to the second recess 2d is preferably 1 / 10 or more, more preferably 1 / 8 or more, and still more preferably 1 / 5 or more with respect to the length of the sealing plate 2.

[0086] As shown in FIG. 17, a third recess 2e is provided on the surface of the sealing plate 2 on the side of the electrode body 3. As shown in FIG. 18, a third protrusion 72 is provided on a portion of the internal side insulating member 12 disposed between the sealing plate 2 and the second negative electrode current collector 8b and facing the sealing plate 2. In the rectangular secondary battery 20, the third protrusion 72 is disposed in the third recess 2e. Thereby, it is possible to suppress the internal side insulating member 12 from being largely displaced with respect to the sealing plate 2 in a plane parallel to the sealing plate 2.

[0087] Note that the shapes of the third protrusion 72 and the third recess 2e are not particularly limited. When viewed from a direction perpendicular to the sealing plate 2, the shape of the third protrusion 72 is preferably circular. Further, when viewed from a direction perpendicular to the sealing plate 2, the shape of the third recess 2e is preferably circular, and more preferably oval.

[0088] The difference between the width of the third recess 2e and the width of the third protrusion 72 in the short direction of the sealing plate 2 is preferably 5 mm or less, more preferably 3 mm or less, and still more preferably 1 mm or less.

[0089] When viewed from a direction perpendicular to the sealing plate 2, the width of the third recess 2e in the longitudinal direction of the sealing plate 2 is preferably larger than the width of the third recess 2e in the short direction of the sealing plate 2.

[0090] The difference between the width of the third recess 2e and the width of the third protrusion 72 in the longitudinal direction of the sealing plate 2 is preferably larger than the difference between the width of the third recess 2e and the width of the third protrusion 72 in the short direction of the sealing plate 2. With such a configuration, it is possible to suppress the displacement of the inner-side insulating member 12 with respect to the sealing plate 2 in the short direction of the sealing plate 2, and it becomes possible to easily assemble the inner-side insulating member 12 to the sealing plate 2.

[0091] Note that the shape of the third protrusion 72 and the third recess 2e in plan view is preferably linear or dot-like, and more preferably dot-like. In the short direction of the sealing plate 2, the third recess 2e is preferably shifted toward the end side of the sealing plate 2 from the center of the sealing plate 2. With such a configuration, even when the third recess 2e is provided in the sealing plate 2, it is possible to suppress a decrease in the strength of the sealing plate 2.

[0092] In the short direction of the sealing plate 2, the first recess 2c in which the first protrusion 70 provided on the second insulating member 63 disposed between the sealing plate 2 and the second positive current collector 6b is disposed inside is located on one side from the center of the sealing plate 2, and the third recess 2e in which the third protrusion 72 provided on the inner-side insulating member 12 disposed between the sealing plate 2 and the second negative current collector 8b is disposed inside is preferably located on the other side from the center of the sealing plate 2. With such a configuration, it is possible to suppress a decrease in the strength of the sealing plate 2. [Modification Example 1] The rectangular secondary battery according to Modification 1 has the same configuration as the rectangular secondary battery 20 according to the above-described embodiment, except that the shapes of the first positive electrode tab group 40a and the second positive electrode tab group 40b are different. FIG. 19 is a cross-sectional view of the rectangular secondary battery according to Modification 1 with respect to FIG. 16. Further, FIG. 20 is an enlarged view of the vicinity of the first positive electrode tab group 40a in FIG. 19. FIG. 21 is an enlarged view of the vicinity of the second positive electrode tab group 40b in FIG. 19.

[0093] The first positive electrode tab group 40a and the second positive electrode tab group 40b are each in a curved state and are connected to a portion of the second positive electrode current collector 6b that is disposed along the sealing plate 2. Because of such a configuration, a rectangular secondary battery with a higher volume energy density is obtained.

[0094] The second insulating member 63 as an insulating member has a base portion 630a disposed between the sealing plate 2 and the second positive electrode current collector 6b as a current collecting member, and a first wall portion 630b that protrudes from one end of the base portion 630a in the short side direction of the sealing plate 2 toward the electrode body 3. And the first wall portion 630b is disposed between the first positive electrode tab group 40a and the rectangular exterior body 1. For this reason, a structure is formed in which the first positive electrode tab group 40a and the rectangular exterior body 1 are difficult to come into direct contact. Therefore, a rectangular secondary battery with higher reliability is obtained.

[0095] The base portion 630a of the second insulating member 63 as an insulating member is provided with a second wall portion 630c that protrudes from the other end of the base portion 630a in the short side direction of the sealing plate 2 toward the electrode body 3. And the second wall portion 630c is disposed between the second positive electrode tab group 40b and the rectangular exterior body 1. For this reason, a structure is formed in which the second positive electrode tab group 40b and the rectangular exterior body 1 are difficult to come into direct contact. Therefore, a rectangular secondary battery with higher reliability is obtained.

[0096] Further, the positive electrode current collecting member 6 is composed of a first positive electrode current collector 6a and a second positive electrode current collector 6b, and the first positive electrode tab group 40a and the second positive electrode tab group 40b are connected to the second positive electrode current collector. For this reason, a rectangular secondary battery having a higher volume energy density can be manufactured by a simpler method.

[0097] As shown in FIG. 20, the first positive electrode tab group 40a has a first connection region 500 disposed on the second positive electrode current collector 6b, and a first curved region 501 that extends from the end of the first connection region 500 on the side of the first wall portion 630b toward the electrode body 3 and is curved so as to bulge toward the first wall portion 630b. On the surface of the first positive electrode tab group 40a on the side of the rectangular exterior body 1, a first recessed region 502 that is recessed toward the center side (right side in FIG. 20) of the sealing plate 2 in the short side direction of the sealing plate 2 is provided on the electrode body 3 of the first curved region 501.

[0098] As shown in FIG. 21, the second positive electrode tab group 40b has a second connection region 503 disposed on the second positive electrode current collector 6b, and a second curved region 504 that extends from the end of the second connection region 503 on the side of the second wall portion 630c toward the electrode body 3 and is curved so as to bulge toward the second wall portion 630c. On the surface of the second positive electrode tab group 40b on the side of the rectangular exterior body 1, a second recessed region 505 that is recessed toward the center side (left side in FIG. 21) of the sealing plate 2 in the short side direction of the sealing plate 2 is provided on the electrode body 3 of the second curved region 504.

[0099] In the short side direction of the sealing plate 2 (the left - right direction in FIG. 19), when the distance between the portion of the first curved region 501 that is located closest to the rectangular exterior body 1 and the portion of the second curved region 504 that is located closest to the rectangular exterior body 1 is D1, and the distance between the first wall portion 630b and the second wall portion 630c is D2, it is preferable that D2≧D1. With such a configuration, it is possible to more reliably prevent the first positive electrode tab group 40a to the second positive electrode tab group 40b from directly contacting the rectangular exterior body 1.

[0100] Note that the outer surface of the first curved region 501 may be in contact with the first wall portion 630b. The outer surface of the second curved region 504 may be in contact with the second wall portion 630c. With such a configuration, it is possible to more effectively suppress the first positive electrode tab group 40a to the second positive electrode tab group 40b from having an unintended shape. For this reason, it is possible to more effectively prevent the positive electrode tabs 40 that constitute the first positive electrode tab group 40a to the second positive electrode tab group 40b from being damaged or injured. Alternatively, it is possible to more effectively prevent an unexpected short - circuit between the positive and negative electrodes from occurring.

[0101] In the rectangular secondary battery 20 according to the above-described embodiment, an example in which the second insulating member 63 has a base portion 630a, a first wall portion 630b, and a second wall portion 630c disposed between the sealing plate 2 and the second positive electrode current collector 6b was shown. Instead of providing the base portion and the wall portion on the second insulating member 63, the first insulating member 10 may have a base portion disposed between the sealing plate 2 and the second positive electrode current collector 6b and a wall portion extending from the base portion toward the electrode body 3 side.

[0102] In the rectangular secondary battery 20 according to the above-described embodiment, an example in which the first wall portion 630b and the second wall portion 630c are provided on the base portion 630a was shown. However, only one of the first wall portion 630b and the second wall portion 630c may be provided. It is preferable to provide both the first wall portion 630b and the second wall portion 630c on the base portion 630a.

[0103] In the rectangular secondary battery 20 according to the above-described embodiment, an example in which a plurality of positive electrode tabs 40 are divided into a first positive electrode tab group 40a and a second positive electrode tab group 40b was shown, but they can also be made into one tab group. It is preferable to provide the first positive electrode tab group 40a and the second positive electrode tab group 40b.

[0104] The rectangular secondary battery 20 according to the above-described embodiment has a current interruption mechanism 60, but the current interruption mechanism 60 may not be provided. When the current interruption mechanism 60 is not provided, the positive electrode side can have the same configuration as the negative electrode side of the rectangular secondary battery 20.

[0105] In the rectangular secondary battery 20 according to the above-described embodiment, an example in which the positive electrode current collecting member is composed of two components, the first positive electrode current collector 6a and the second positive electrode current collector 6b, was shown, but the positive electrode current collecting member can also be made into one component. Further, in the rectangular secondary battery 20 according to the above-described embodiment, an example in which the negative electrode current collecting member is composed of two components, the first negative electrode current collector 8a and the second negative electrode current collector 8b, was shown, but the negative electrode current collecting member can also be made into one component.

[0106] In the rectangular secondary battery 20 according to the above-described embodiment, an example in which the first positive tab group 40a and the second positive tab group 40b, and the first negative tab group 50a and the second negative tab group 50b are curved in different directions has been shown. However, the present invention is not limited to this, and the first positive tab group 40a and the second positive tab group 40b may be curved in the same direction, and the first negative tab group 50a and the second negative tab group 50b may be curved in the same direction.

[0107] In the rectangular secondary battery 20 according to the above-described embodiment, an example in which the positive electrode terminal 7 and the negative electrode terminal 9 are insulated from the sealing plate 2 has been shown, but one of the positive electrode terminal 7 and the negative electrode terminal 9 can be electrically connected to the sealing plate 2.

[0108] The gas discharge valve 17 provided in the sealing plate 2 is preferably a thin-walled portion provided in the sealing plate 2. Such a thin-walled portion as the gas discharge valve 17 is formed, for example, by press molding. Further, a through hole may be provided in the sealing plate 2, the through hole may be closed with a thin-walled valve body, and the valve body may be welded to the sealing plate 2. <Others> The fracture prediction portion that fractures as the deformation plate deforms is preferably a fragile portion provided in the current collecting member, a connection portion between the current collecting member and the deformation plate, or a fragile portion provided in the deformation plate. As the fragile portion, a thin-walled portion, a notch, or the like is preferable.

[0109] The first insulating member, the second insulating member, and the cover portion are preferably made of resin. For example, those made of polypropylene, polyethylene, perfluoroalkoxy alkane (PFA), polytetrafluoroethylene (PTFE), or ethylene tetrafluoroethylene copolymer (ETFE) can be used.

[0110] In the above-described embodiment, an example where the electrode body 3 is composed of two electrode body elements 3a and 3b has been shown, but the present invention is not limited thereto. The electrode body 3 may be a single laminated electrode body. Further, the electrode body 3 may be a single wound electrode body in which a long positive electrode plate and a long negative electrode plate are wound with a separator interposed therebetween. Further, the two electrode body elements 3a and 3b are not limited to laminated electrode bodies, respectively, and may be wound electrode bodies in which a long positive electrode plate and a long negative electrode plate are wound with a separator interposed therebetween.

[0111] In the case where the electrode body is a laminated electrode body having a plurality of positive electrode plates and a plurality of negative electrode plates, or when the electrode body is a wound electrode body and its winding axis is arranged in a direction perpendicular to the sealing plate, in the electrode body, it is preferable that the end portion of the positive electrode plate, the end portion of the negative electrode plate, and the end portion of the separator are located on the sealing plate side. With such a configuration, when an electrolyte injection hole is provided in the sealing plate, the injectability of the electrolyte into the electrode body is improved. In such a case, it is preferable that the end portion of the separator on the sealing plate side protrudes toward the sealing plate 2 side more than the end portion of the negative electrode active material mixture layer on the sealing plate side in the negative electrode plate. Further, in the electrode body, it is preferable that the end portion of the separator on the sealing plate side protrudes toward the sealing plate side more than the end portion of the positive electrode active material mixture layer on the sealing plate side in the positive electrode plate. Further, it is preferable that the positive electrode plate and the separator are adhered by an adhesive layer, and the negative electrode plate and the separator are adhered by an adhesive layer. With such a configuration, it is possible to surely prevent the positive electrode active material mixture layer and the negative electrode active material mixture layer from contacting the second insulating member and damaging the positive electrode active material layer or the negative electrode active material layer.

Explanation of Reference Numerals

[0112] 20... Square secondary battery 1... Square exterior body 2... Sealing plate 2a... Positive electrode terminal attachment hole 2b... Negative electrode terminal attachment hole 2c... First recess 2d... Second recess 2e... Third recess 100... Battery case 3... Electrode body 3a ··· The first electrode body element 3b ··· The second electrode body element 4 ··· The positive electrode plate 4a ··· The positive electrode core 4b ··· The positive electrode active material mixture layer 4d ··· The positive electrode protective layer 40 ··· The positive electrode tab 40a ··· The first positive electrode tab group 40b ··· The second positive electrode tab group 500 ··· The first connection region 501 ··· The first bending region 502 ··· The first recessed region 503 ··· The second connection region 504 ··· The second bending region 505 ··· The second recessed region 5 ··· The negative electrode plate 5a ··· The negative electrode core 5b ··· The negative electrode active material mixture layer 50 ··· The negative electrode tab 50a ··· The first negative electrode tab group 50b ··· The second negative electrode tab group 6 ··· The positive electrode current collector member 6a ··· The first positive electrode current collector 6c ··· The connection hole 6d ··· The fixing hole 6d1 ··· The small diameter part 6d2 ··· The large diameter part 6e ··· The displacement prevention hole 6f ··· The thin part 6g ··· The notch 6h ··· The connection rib 6x ··· The current collector protrusion 6w ··· The second recess of the current collector 6b ··· The second positive electrode current collector 6b1 ··· The first region of the current collector 6b2 ··· The second region of the current collector 6b3 ··· The third region of the current collector 6k ··· The target hole 6m ··· The first recess of the current collector 6y ··· The first opening of the current collector 6z ··· The second opening of the current collector 7 ··· The positive electrode terminal 7a ··· Flange part 7b ··· Insertion part 7c ··· Terminal through-hole 7x ··· Terminal sealing member 7y ··· Metal member 7z ··· Rubber member 8 ··· Negative electrode current collector member 8a ··· First negative electrode current collector 8x ··· Current collector protrusion 8w ··· Current collector second recess 8b ··· Second negative electrode current collector 8b1 ··· Current collector first region 8b2 ··· Current collector second region 8b3 ··· Current collector third region 8e ··· Target hole 8f ··· Current collector first recess 8y ··· Current collector first opening 9 ··· Negative electrode terminal 10 ··· First insulating member 10a ··· First insulating member main body part 10b ··· First side wall 10c ··· Second side wall 10d ··· Second terminal insertion hole 10e ··· First connection part 10f ··· Second connection part 10g ··· Recess 10x ··· First groove part 10y ··· Second groove part 11 ··· Outer side insulating member 11a ··· First terminal insertion hole 12 ··· Inner side insulating member 13 ··· Outer side insulating member 14 ··· Insulating sheet 15 ··· Electrolyte injection hole 16 ··· Sealing plug 17 ··· Gas discharge valve 60 ··· Current interruption mechanism 61 ··· Conductive member 61a ··· Conductive member base part 61b ··· Tubular part 61c ··· Third terminal insertion hole 61d ··· Flange part 61e ··· Pressing projection 61f ··· Conductive member opening 62 ··· Deformable plate 62a ··· Step projection 62a1 ··· First protruding portion 62a2 ··· Second protruding portion 62b ··· Annular rib 62c ··· Annular thin-walled portion 63 ··· Second insulating member 63x ··· Insulating member first region 63a ··· Insulating member first opening 63b ··· Third wall portion 63c ··· Fourth wall portion 63d ··· Third connecting portion 63e ··· Fourth connecting portion 63f ··· Fixing projection 63f1 ··· Diameter-expanded portion 63g ··· Displacement prevention projection 63h ··· Claw portion 63y ··· Insulating member second region 63i ··· Insulating member second opening 63k ··· Insulating member annular rib 630a ··· Base portion 630b ··· First wall portion 630c ··· Second wall portion 63z ··· Insulating member third region 70 ··· First convex portion 71 ··· Second convex portion 72 ··· Third convex portion 80 ··· Cover portion 90 ··· Weld connection portion

Claims

1. An electrode body including a positive electrode plate and a negative electrode plate; A rectangular exterior body having an opening and housing the electrode body; A sealing plate that seals the opening and has a longitudinal direction and a lateral direction; An electrolyte injection hole provided in the sealing plate; A tab provided on the positive electrode plate or the negative electrode plate; A tab group composed of a plurality of the tabs; A terminal electrically connected to the tab group and attached to the sealing plate; A current collecting member electrically connected to the tab group and the terminal; An insulating member disposed between the sealing plate and the current collecting member, and comprising: The electrode body includes a first electrode body element including a positive electrode plate and a negative electrode plate, and a second electrode body element including a positive electrode plate and a negative electrode plate; The first electrode body element and the second electrode body element are arranged in the lateral direction of the sealing plate; A first tab group of one of the positive electrode plate and the negative electrode plate in the first electrode body element and a second tab group of one of the positive electrode plate and the negative electrode plate in the second electrode body element are electrically connected to the current collecting member; In the current collecting member, a connection portion with the first tab group and a connection portion with the second tab group are arranged in the lateral direction of the sealing plate; In the lateral direction of the sealing plate, the electrolyte injection hole is disposed between the connection portion with the first tab group and the connection portion with the second tab group; Each of the first tab group and the second tab group is curved; An insulating sheet is interposed between the electrode body and the rectangular exterior body. A rectangular secondary battery.

2. The insulating member has an opening in a region facing the electrolyte injection hole. The rectangular secondary battery according to Claim 1.

3. The insulating member has ribs formed around the opening and protruding from the insulating member toward the electrode body. The rectangular secondary battery according to Claim 2.

4. In the lateral direction of the sealing plate, the first tab group is bent so as to fall toward the second tab group side, and the second tab group is bent so as to fall toward the first tab group. The rectangular secondary battery according to any one of Claims 1 to 3.

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