Batteries and battery packs

Abstract

The present invention provides a battery having a flat battery case formed by shallow drawing, in which the connection structure between the power generation element and the terminals is simple, and the terminals can be removed from the side wall, and a battery pack using this battery. [Solution] The power generation element has multiple positive electrodes, negative electrodes, and separators. The electrode tabs include positive electrode tabs and negative electrode tabs. The battery case has a flat, rectangular, shallow-drawn shape and houses the power generation element and electrode tabs. The connecting plate is connected to either the positive electrode tab or the negative electrode tab. The external terminals are connected to the connecting plate and penetrate the side wall. The power generation element is housed in the battery case. The electrode tabs protrude from the ends of the power generation element. The connecting plate includes a first connecting portion and a second connecting portion. The first connecting portion is a flat plate-shaped part positioned parallel to the bottom and overlapping the bottom. The second connecting portion rises from the edge of the first connecting portion in the same direction as the side wall and parallel to the side wall, and is connected to the external terminals.

Description

Technical Field

[0001] The present invention relates to batteries and battery packs.

Background Art

[0002] There is known a battery in which a power generation element (electrode group) is housed in a flat square battery can (outer container) formed by shallow drawing. Patent Document 1 (International Publication No. 2016 / 204147) discloses a battery in which a terminal is provided on an inclined surface formed between an end portion (side wall portion) and a main surface of a flat outer container. Patent Document 2 (Japanese Unexamined Patent Application Publication No. 2015-185247) discloses a battery in which a terminal is provided on the main surface of a flat outer can.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] When a terminal is provided on an inclined surface formed in a flat outer container as in the battery of Patent Document 1, the connection structure between the power generation element and the terminal tends to be complicated.

[0005] When a terminal is provided on the main surface of a flat outer container as in the battery of Patent Document 2, when gas accumulates inside due to deterioration of the battery, the terminal may be damaged along with the curvature of the main surface. Further, when a terminal is provided on the main surface of a flat outer container, it is difficult to take out the terminal when used as a battery pack in which a plurality of batteries are stacked in the thickness direction.

[0006] The object of the present invention is to provide a battery having a flat battery case formed by shallow drawing, in which the connection structure between the power generation element and the terminals is simple, and the terminals can be removed from the side wall, and a battery pack using this battery. [Means for solving the problem]

[0007] Several embodiments for solving the problem are described below. These embodiments can be combined as needed.

[0008] A battery according to a first aspect of the present invention comprises a power generation element, electrode tabs, a battery case, a connecting plate, external terminals, and an insulating plate. The power generation element has a flattened shape and has a plurality of positive electrodes, negative electrodes, and separators. The electrode tabs include a positive electrode tab electrically connected to or integrally formed with the positive electrode, and a negative electrode tab electrically connected to or integrally formed with the negative electrode. The battery case has a flattened, rectangular, shallow-drawn shape with a bottom and side walls rising from the bottom edge, and houses the power generation element and electrode tabs. The connecting plate is connected to either the positive electrode tab or the negative electrode tab. The external terminals are connected to the connecting plate and penetrate the side walls. The power generation element is housed in the battery case with its main surface facing the bottom. The electrode tabs protrude from the ends of the power generation element. The insulating plate is laminated between the battery case and the connecting plate.

[0009] The connecting plate includes a first connecting portion and a second connecting portion. The first connecting portion is a flat plate-like part positioned parallel to the bottom and overlapping the bottom. The second connecting portion rises from the edge of the first connecting portion in the same direction as the side wall and parallel to the side wall, and is connected to the external terminal.

[0010] The connecting plate has a first connecting portion arranged parallel to the bottom and a second connecting portion formed parallel to the side wall and connected to an external terminal that penetrates the side wall. This allows for an electrical connection between the power generation element and the external terminal with a simple connection structure, by connecting the electrode tab to the first connecting portion arranged parallel to the bottom, and also allows the external terminal to be brought out from the side wall. Therefore, this battery, which has a flat battery case formed by shallow drawing, has a simple connection structure between the power generation element and the external terminal, while allowing the external terminal to be brought out from the side wall.

[0011] A battery according to a second aspect of the present invention is a battery according to the first aspect, wherein the insulating plate includes a first insulating portion and a second insulating portion. The first insulating portion is a flat plate-shaped portion laminated between a first connection portion and a bottom portion. The second insulating portion is a flat plate-shaped portion that rises from the edge of the first insulating portion in the same direction as the side wall portion and is laminated between the second connection portion and the side wall portion.

[0012] As a result, the connecting plate is insulated from the battery can by the insulating plate.

[0013] A battery according to a third aspect of the present invention is a battery according to the first or second aspect, further comprising a cover plate that closes an opening formed at the end of the side wall opposite to the bottom.

[0014] As a result, the opening of this battery is closed by the cover plate.

[0015] A battery according to the fourth aspect of the present invention is a battery according to any of the first or third aspects, wherein at least one of the connecting plate and the insulating plate has an anti-slip portion.

[0016] This makes it possible to connect the connecting plate and the insulating plate using ultrasonic bonding.

[0017] A battery according to the fifth aspect of the present invention is a battery according to the fourth aspect, wherein the anti-slip portion has an uneven cross-sectional shape.

[0018] The assembled battery according to the sixth aspect of the present invention is configured by stacking a plurality of the above-described batteries.

Advantages of the Invention

[0019] This battery has a simple connection structure between the power generation element and the external terminal, and the terminal can be taken out from the side wall portion.

Brief Description of the Drawings

[0020] [Figure 1] It is an exploded perspective view of the battery 1. [Figure 2] It is a perspective view around the insulating plate 6. [Figure 3] It is a cross-sectional view taken along the A surface of FIG. 2. [Figure 4] It is a plan view of the first insulating portion 61 showing the concavo-convex shape 61a.

Embodiments for Carrying Out the Invention

[0021] <Embodiment> (1) Overall Configuration The battery 1 according to an embodiment of the present invention is a lithium-ion secondary battery and has a rectangular flat shape. The battery 1 includes a power generation element 2, an electrode tab 3, a battery can 4, a cover plate 5, an insulating plate 6, a connection plate 7, an external terminal 8, and a non-aqueous electrolyte (not shown). FIG. 1 is an exploded perspective view of the battery 1 according to an embodiment of the present invention. FIG. 2 is a perspective view around the insulating plate 6. FIG. 3 is a cross-sectional view taken along the A surface of FIG. 2. In FIG. 1, for the sake of convenience, a part of the positive electrode 21, the negative electrode 22, and the separator 23, which will be described later, are shown transparently. Also, in FIG. 2, for the sake of convenience, the illustration of the power generation element 2 and the electrode tab 3 is omitted.

[0022] (2) Detailed Configuration (2-1) Power Generation Element 2 The power generation element 2 has multiple positive electrodes 21, multiple negative electrodes 22, and multiple separators 23. As shown in Figure 1, the power generation element 2 has a flattened shape. The positive electrodes 21 and negative electrodes 22 are stacked alternately with separators 23 in between. Separators 23 are also stacked on the outermost part of the power generation element 2. The power generation element 2 is housed in the battery can 4 lying on its side, that is, with the main surface of the power generation element 2 facing the bottom 41 of the battery can 4, which will be described later.

[0023] (2-1-1) Positive electrode 21 The positive electrode 21 is a strip-shaped member in which a positive electrode active material layer is supported on both sides of the positive electrode current collector.

[0024] The positive electrode current collector collects current from the positive electrode active material layer. The positive electrode current collector is composed of a metal foil such as aluminum, titanium, stainless steel, nickel, or iron, or an alloy foil made of these materials. The positive electrode current collector has a thickness of approximately 1 μm to approximately 500 μm.

[0025] The positive electrode active material layer contains a positive electrode active material capable of intercalating and releasing lithium ions. The positive electrode active material is, for example, a lithium-containing oxide. Specifically, lithium-containing oxides include LiCoO2, LiFeO2, LiMnO2, LiMn2O4, and compounds in which some of the transition metals in these oxides are replaced with other metal elements.

[0026] (2-1-2) Negative electrode 22 The negative electrode 22 is a strip-shaped member in which a negative electrode active material layer is supported on both sides of the negative electrode current collector. The negative electrode 22 is formed to be larger than or equal to the positive electrode 21.

[0027] The negative electrode current collector collects current from the negative electrode active material layer. This negative electrode current collector is composed of, for example, metal foil such as copper, nickel, stainless steel, iron, or a nickel-plated layer, or alloy foil made of these alloys. The negative electrode current collector has a thickness of approximately 1 μm to approximately 100 μm.

[0028] The negative electrode active material layer contains a negative electrode active material capable of intercalating and releasing lithium ions. The negative electrode active material is, for example, a substance capable of intercalating and releasing lithium. Specifically, a substance capable of intercalating and releasing lithium is particulate (flaky, lumpy, fibrous, whisker-like, spherical, or pulverized) natural or artificial graphite. The negative electrode active material may also be artificial graphite obtained by graphitizing mesocarbon microbeads, mesophase pitch powder, isotropic pitch powder, etc. Furthermore, the negative electrode active material may be graphite particles with amorphous carbon surface-deposited. In addition, the negative electrode active material may be lithium transition metal oxides, lithium transition metal nitrides, transition metal oxides, and silicon oxide. Examples of lithium transition metal oxides include Li4Ti5O 12 It is preferable that the material be lithium titanate, such as the one shown.

[0029] (2-1-3) Separator 23 The separator 23 is an insulating strip-shaped member having ions that permeate through it. The separator 23 is formed to be larger than or equal to the positive electrode 21 and the negative electrode 22. The separator 23 is stacked between the positive electrode 21 and the negative electrode 22, insulating adjacent positive electrode 21 and negative electrode 22. The separator 23 also insulates the power generation element 2 from the battery can 4 and the cover plate 5.

[0030] The separator 23 should have sufficient strength and be able to hold a large amount of non-aqueous electrolyte. From this viewpoint, the separator 23 is preferably formed from a microporous film or nonwoven fabric containing polyethylene, polypropylene, or ethylene-propylene copolymer, for example. In addition, the separator 23 may be a microporous film made of polymers such as polyvinylidene fluoride, polyvinylidene chloride, polyacrylonitrile, polyacrylamide, polytetrafluoroethylene, polysulfone, polyethersulfone, polycarbonate, polyamide, polyimide, polyether, cellulose, poly(meth)acrylic acid, or poly(meth)acrylic acid ester. Furthermore, it may be a multilayer film made by stacking these microporous films. The thickness of the separator 23 is preferably 5 μm to 100 μm. The porosity of the separator 23 is preferably 30% to 90%.

[0031] (2-2) Electrode tab 3 The electrode tab 3 includes a positive electrode tab 31 and a negative electrode tab 32.

[0032] The positive electrode tab 31 is a strip-shaped member made of the same material as the positive electrode current collector. One end of the positive electrode tab 31 is connected to the positive electrode current collector of the positive electrode 21, and the other end is joined to the inner surface of the battery can 4. As a result, the battery can 4 and the cover plate 5 function as the positive electrode of the battery 1. The positive electrode tab 31 may be made of a different material from the positive electrode current collector, as long as it can electrically connect the positive electrode 21 and the battery can 4. Alternatively, the positive electrode tab 31 may be formed integrally with the positive electrode 21 as part of the positive electrode 21.

[0033] The negative electrode tab 32 is a strip-shaped member formed from the same material as the negative electrode current collector. One end of the negative electrode tab 32 is connected to the negative electrode current collector of the negative electrode 22, and the other end is joined to the connecting plate 7, which will be described later, using ultrasonic bonding. As a result, the external terminal 8, which will be described later, functions as the negative electrode of the battery 1. The negative electrode tab 32 may be made of a different material from the negative electrode current collector, as long as it can electrically connect the negative electrode 22 and the connecting plate 7. Alternatively, the negative electrode tab 32 may be formed integrally with the negative electrode 22 as part of the negative electrode 22.

[0034] The positive electrode tab 31 and the negative electrode tab 32 are provided so as to protrude from the end face of the power generation element 2. In this embodiment, the positive electrode tab 31 and the negative electrode tab 32 are provided so as to protrude from the same end 24 of the power generation element 2.

[0035] (2-3) Battery can 4 The battery casing 4 is a flat, rectangular, shallow-drawn shape that houses the power generation element 2 and the electrode tabs 3. The battery casing 4 is formed by shallow drawing of a metal sheet. The battery casing 4 has a bottom portion 41, a side wall portion 42, an opening 43, and a flange 44.

[0036] The bottom portion 41 is rectangular in shape. The side walls 42 are surfaces that rise from each of the four sides of the bottom portion 41. From the viewpoint of ensuring load-bearing capacity in the thickness direction, it is preferable that the angle between all the side walls 42 and the bottom portion 41 is between 80 degrees and 100 degrees. In this way, when the battery cans are stacked in the thickness direction to form a battery pack, the proportion of the bottom portion 41 and opening 43 of the battery can that are in contact with adjacent battery cans increases, thus ensuring load-bearing capacity in the thickness direction and suppressing expansion of the battery cans. For example, in this embodiment, all the side walls 42 are at an angle of 90 degrees with the bottom portion 41. The opening 43 is made up of the ends of the four side walls 42 opposite to the bottom portion 41. A flange 44 may be provided around the opening 43. Providing a flange 44 makes welding work between the opening 43 and the cover plate 5 easier. The flange 44 is provided so as to extend around the opening 43 from the ends of the four side walls 42 opposite to the bottom 41. The flange 44 is formed to be parallel to the bottom 41.

[0037] The bottom portion 41, the side wall portion 42, and the opening 43 are formed to a size that allows the power generation element 2 to be housed lying down, that is, with the main surface of the power generation element 2 facing the bottom portion 41. The opening 43 is formed to be the same size as the bottom portion 41, or slightly larger than the bottom portion 41. The flange 44 is formed to be large enough to weld and fix the outer edge of the cover plate 5, which will be described later.

[0038] Shallow drawing is a type of deep drawing. Deep drawing is a manufacturing method that creates bottomed containers of various shapes seamlessly from a single thin metal sheet. Generally, deep drawing is used to create containers whose depth is shallow compared to the opening size (the diameter of a cylindrical opening, or the rim of a rectangular opening), such as ashtrays or frying pans, while deep drawing is used to create containers whose depth is greater than the opening size. In this invention, shallow drawing is used to form a battery can 4 with the main surface of a rectangular, flattened battery 1 as the bottom.

[0039] The metal sheets used for shallow drawing of the battery can 4 are, for example, iron, stainless steel, aluminum, or copper. The thickness of the metal sheets is, for example, 0.1 mm to 2.0 mm.

[0040] One of the four side walls 42 has a hole 42a through which an external terminal 8 passes. One of the four side walls 42 may be provided with a safety valve that opens when the internal pressure of the battery exceeds a specified pressure.

[0041] (2-4) Lid plate 5 The cover plate 5 is a flat, metal plate. The cover plate 5 closes the opening 43 of the battery can 4 by welding its outer edge to the perimeter of the opening 43. If the battery can 4 has a flange 44, the cover plate 5 is welded to the flange 44. In this way, the cover plate 5 and the battery can 4 constitute the outer casing of the battery 1. The cover plate 5 is rectangular in shape so as to close the opening 43 of the battery can 4. The metal plate used for the cover plate 5 may be the same material and thickness as that used for the battery can 4.

[0042] (2-5) Insulating board 6 The insulating plate 6 is a flat plate-shaped member that insulates the connecting plate 7 from the battery can 4. The insulating plate 6 is laminated between the connecting plate 7 and the battery can 4. As shown in Figure 3, the insulating plate 6 is housed inside the battery can 4 such that one side faces the bottom 41 and side wall 42 of the battery can 4. The insulating plate 6 has a first insulating portion 61 and a second insulating portion 62. Details of the material of the insulating plate 6 will be described later.

[0043] The first insulating portion 61 is a rectangular, flat plate-shaped member that is laminated between the first connecting portion 71 (described later) of the connecting plate 7 and the bottom portion 41. One side of the first insulating portion 61 faces the bottom portion 41 of the battery can 4, and the other side faces the first connecting portion 71 of the connecting plate 7. Preferably, the first insulating portion 61 is provided with an anti-slip portion on the side facing the first connecting portion 71. By providing an anti-slip portion, the coefficient of friction between the connecting plate 7 and the insulating plate 6 is increased, enabling ultrasonic bonding between the negative electrode tab 32 and the connecting plate 7 when housed in the battery can 4. Details of the anti-slip portion will be described later.

[0044] The second insulating portion 62 is a rectangular, flat member that rises from the edge of the first insulating portion 61 in the same direction as the side wall portion 42. The second insulating portion 62 is laminated between the second connecting portion 72 (described later) of the connecting plate 7 and the side wall portion 42. One side of the second insulating portion 62 faces the side wall portion 42 of the battery can 4, and the other side faces the second connecting portion 72 of the connecting plate 7. For example, in this embodiment, the second insulating portion 62 has an angle of 90 degrees with the first insulating portion 61. The second insulating portion 62 has a hole 62a formed therein for passing the external terminal 8 through. The hole 62a is formed in a position and shape that forms a single through-hole with the hole 42a formed in the side wall portion 42 when the insulating plate 6 is housed inside the battery can 4.

[0045] (2-6) Connecting plate 7 The connecting plate 7 is a flat, metal member that electrically connects the negative electrode tab 32 and the external terminal 8. As shown in Figure 3, the connecting plate 7 is placed on top of the insulating plate 6 so as to face the side of the insulating plate 6 opposite to the side of the insulating plate 6 that faces the battery can 4, and is housed inside the battery can 4. The connecting plate 7 has a first connecting portion 71 and a second connecting portion 72. For example, the connecting plate 7 can be made of iron, stainless steel, aluminum, copper, etc. The material used for the connecting plate 7 may be the same as or different from that used for the battery can 4.

[0046] The first connecting portion 71 is a rectangular, flat member positioned parallel to the bottom portion 41 and overlapping it. One side of the first connecting portion 71 faces the first connecting portion 71 of the insulating plate 6, and the other side contacts the negative electrode tab 32. The first connecting portion 71 is formed to be approximately the same size and shape as the first insulating portion 61 of the insulating plate 6. Preferably, the first connecting portion 71 is provided with an anti-slip portion on the side facing the first insulating portion 61. By providing an anti-slip portion, the coefficient of friction between the connecting plate 7 and the insulating plate 6 increases, enabling ultrasonic bonding between the negative electrode tab 32 and the connecting plate 7 when housed in the battery can 4. Details of the anti-slip portion will be described later.

[0047] The second connecting portion 72 is a rectangular, flat member that rises from the edge of the first connecting portion 71 in the same direction as the side wall portion 42. One side of the second connecting portion 72 faces the second insulating portion 62 of the insulating plate 6. For example, the second connecting portion 72 has an angle of 90 degrees with the first connecting portion 71. The second connecting portion 72 is connected to the external terminal 8. The second connecting portion 72 has a hole 72a formed therein for the external terminal 8 to pass through. The hole 72a is formed in a position and shape such that, when the connecting plate 7 is superimposed on the insulating plate 6 housed inside the battery can 4, it forms a single through-hole with the hole 62a in the insulating plate 6 and the hole 42a formed in the side wall portion 42.

[0048] (2-7) External terminal 8 The external terminal 8 is a metal component electrically connected to the connecting plate 7. In this embodiment, the external terminal 8 is formed in a cylindrical shape.

[0049] The external terminal 8 is positioned to pass through the hole 42a formed in the side wall portion 42, the hole 62a formed in the insulating plate 6, and the hole 72a formed in the connecting plate 7, when the insulating plate 6 and the connecting plate 7 are housed in the battery can 4. The external terminal 8 is electrically connected to the connecting plate 7 by contacting the second connecting portion 72 formed in the connecting plate 7.

[0050] The external terminal 8 is partially exposed to the outside of the battery can 4 through a hole 42a. In this embodiment, the external terminal 8 has a large-diameter portion 81 formed at the end exposed to the outside of the battery can 4, which is larger in diameter than the other parts. A spacer 82 made of insulating material is provided between the large-diameter portion 81 and the outer surface of the battery can 4. The external terminal 8 is fastened to the connecting plate 7 by inserting the tip of the shaft portion of the external terminal 8 into a hole 72a formed in the connecting plate 7 and crimping the tip of the shaft portion of the external terminal 8. In this way, the external terminal 8, the insulating plate 6, and the connecting plate 7 are fixed to the battery can 4.

[0051] (2-8) Non-aqueous electrolyte A non-aqueous electrolyte (not shown) is sealed in the battery can 4 together with the power generation element 2. The solvent for the non-aqueous electrolyte is not particularly limited, but may be esters such as ethylene carbonate (EC), propylene carbonate, butylene carbonate, diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), and γ-butyrolactone; ethers such as tetrahydrofuran, 2-methyltetrahydrofranzine, dioxolane, diethyl ether, dimethoxyethane, diethoxyethane, and methoxyethoxyethane; or polar solvents such as dimethyl sulfoxide, sulfolane, methylsulfolane, acetonitrile, methyl formate, and methyl acetate. These solvents may be used individually or as mixed solvents of two or more types.

[0052] (3) Regarding the connection between the negative electrode tab 32 and the connecting plate 7 As described above, the negative electrode tab 32 and the connecting plate 7 are joined using ultrasonic bonding (ultrasonic welding). Generally, in ultrasonic bonding, the two members to be joined are sandwiched between a horn and an anvil and pressurized, while ultrasonic vibrations output from an oscillator are transmitted to the joining point via the horn. In this process, the anvil, together with the horn, fixes the members and assists in the propagation of ultrasonic vibrations to the joining point. However, in the case of battery 1, the insulating plate 6 and the bottom 41 of the battery can 4 are laminated on the side of the connecting plate 7 opposite to the side that the negative electrode tab 32 contacts. Therefore, when attempting to ultrasonically bond the negative electrode tab 32 and the connecting plate 7 while the battery can 4 is housed there, the anvil cannot be directly applied to the connecting plate 7.

[0053] Therefore, it is preferable that anti-slip portions be provided on the insulating plate 6 and the connecting plate 7. With this configuration, the coefficient of friction between the connecting plate 7 and the insulating plate 6 increases, making ultrasonic bonding between the negative electrode tab 32 and the connecting plate 7 possible while the battery is housed in the battery can 4.

[0054] Specifically, the battery 1 is provided with an anti-slip portion on at least one of the surfaces of the first insulating portion 61 facing the first connecting portion 71 or the surface of the first connecting portion 71 facing the first insulating portion 61. Examples of cross-sectional shapes of the anti-slip portion include mountain shapes, sawtooth shapes, uneven shapes, and rough surface shapes, which increase the surface roughness. In this embodiment, a predetermined uneven shape 61a is formed as an anti-slip portion on the surface of the first insulating portion 61 facing the connecting plate 7. The uneven shape 61a is composed of a plurality of linear recesses and a plurality of linear protrusions. The recesses have a width of, for example, 0.5 millimeters or more and 1 millimeter or less, and are provided at intervals of, for example, 0.5 millimeters to 2.0 millimeters. The protrusions are provided between adjacent recesses. The height from the bottom of a recess to the top of a protrusion is preferably 10% to 40% of the thickness of the first insulating portion 61. In this embodiment, the height from the bottom of the recess to the top of the convex portion is 0.06 millimeters or more and 0.2 millimeters or less. The extension direction of the recess and convex portion is preferably at an angle of 30 degrees or more and less than 60 degrees with respect to the amplitude direction of the horn. Figure 4 is a plan view of the first insulating portion 61 showing the concave and convex shape 61a.

[0055] Furthermore, the material of the insulating plate 6 is preferably one of polypropylene (PP), polyphenylene sulfide (PPS), or polyetheretherketone (PEEK). Using these materials for the insulator improves the support strength and heat resistance of the insulating plate 6, making it easier to ultrasonically bond the negative electrode tab 32 and the connecting plate 7. In particular, polyphenylene sulfide is preferred from the viewpoint of suitably ultrasonically bonding the negative electrode tab 32 and the connecting plate 7 because it has high heat resistance and is less prone to thermal deformation, allowing energy to be reliably applied to the bonding site.

[0056] (4) Features (4-1) The battery 1 comprises a power generation element 2, electrode tabs 3, a battery case 4, a connecting plate 7, an external terminal 8, and an insulating plate 6. The power generation element 2 has a flattened shape with multiple positive electrodes 21, negative electrodes 22, and separators 23. The battery case 4 has a flattened, shallow-drawn rectangular shape with a bottom 41 and side walls 42 rising from the edge of the bottom 41, and houses the power generation element 2 and the electrode tabs 3. The electrode tabs 3 include a positive electrode tab 31 that electrically connects the positive electrode 21 to the battery case 4 and a negative electrode tab 32 that electrically connects the negative electrode 22 to the connecting plate 7. The external terminal 8 connects to the connecting plate 7 and penetrates the side walls 42.

[0057] The power generation element 2 is housed in the battery can 4 with its main surface facing the bottom 41. The electrode tabs 3 protrude from the end 24 of the power generation element 2. The insulating plate 6 is stacked between the battery can 4 and the connecting plate 7.

[0058] The connecting plate 7 includes a first connecting portion 71 and a second connecting portion 72. The first connecting portion 71 is a flat plate-shaped portion positioned parallel to the bottom portion 41 and overlapping with the bottom portion 41. The second connecting portion 72 rises from the edge of the first connecting portion 71 in the same direction as the side wall portion 42 and parallel to the side wall portion 42, and is connected to the external terminal 8.

[0059] The connecting plate 7 has a first connecting portion 71 arranged parallel to the bottom portion 41, and a second connecting portion 72 formed parallel to the side wall portion 42 and connected to an external terminal 8 that penetrates the side wall portion 42. This allows for an electrical connection between the power generation element 2 and the external terminal 8 with a simple connection structure in which the electrode tab 3 is connected to the first connecting portion 71 arranged parallel to the bottom portion 41, and also allows the external terminal 8 to be taken out from the side wall portion 42.

[0060] Therefore, the battery 1, which has a flat battery case 4 formed by shallow drawing, has a simple connection structure between the power generation element 2 and the external terminal 8, while allowing the external terminal 8 to be taken out from the side wall portion 42.

[0061] (4-2) The battery 1 further comprises an insulating plate 6 laminated between the battery can 4 and the connecting plate 7. The insulating plate 6 includes a first insulating portion 61 and a second insulating portion 62. The first insulating portion 61 is a flat plate-shaped portion laminated between the first connecting portion 71 and the bottom portion 41. The second insulating portion 62 is a flat plate-shaped portion that rises from the edge of the first insulating portion 61 in the same direction as the side wall portion 42 and is laminated between the second connecting portion 72 and the side wall portion 42.

[0062] As a result, the connecting plate 7 is insulated from the battery can 4 by the insulating plate 6.

[0063] (4-3) The battery 1 further includes a cover plate 5 that closes an opening 43 formed at the end of the side wall portion 42 opposite to the bottom portion 41.

[0064] As a result, the opening 43 of the battery 1 is closed by the cover plate 5.

[0065] (4-4) At least one of the connecting plate 7 and the insulating plate 6 has an anti-slip portion.

[0066] This makes it possible to connect the connecting plate 7 and the insulating plate 6 using ultrasonic bonding.

[0067] (4-5) The anti-slip surface has an uneven cross-sectional shape.

[0068] (5) Variant (5-1) Variation 1 The power generation element 2 may be composed of a combination of multiple positive electrodes 21, multiple negative electrodes 22, and a single zigzag-folded separator 23. A zigzag fold is a folding method that involves folding in a zigzag pattern. In other words, the separator 23 is a single strip folded in a zigzag pattern by zigzag folding, and is sandwiched between the alternately stacked positive electrodes 21 and negative electrodes 22.

[0069] The power generation element 2 may be a wound type in which a single laminated sheet, comprising a positive electrode 21, a negative electrode 22, and two separators 23, is wound multiple times.

[0070] (5-2) Modification 2 In the above embodiment, the positive electrode tab 31 is connected to the battery can 4 and the negative electrode tab 32 is connected to the connecting plate 7, but the positive electrode tab 31 may be connected to the connecting plate 7 and the negative electrode tab 32 may be connected to the battery can 4. Alternatively, the battery can 4 may be insulated from both the positive electrode 21 and the negative electrode 22, and the positive electrode tab 31 and the negative electrode tab 32 may be connected to different connecting plates, each with different external terminals. If the battery can 4 is electrically connected to either the positive electrode 21 or the negative electrode 22, an external terminal with the same polarity as the battery can 4 does not need to be formed.

[0071] (5-3) Modification 3 Battery 1 may be a primary battery or a secondary battery other than a lithium-ion secondary battery.

[0072] (5-4) Modification 4 Battery 1 may be used as a battery pack by stacking multiple units in the thickness direction.

[0073] As described above, since the external terminals of battery 1 are exposed from the side wall portion 42, when multiple batteries 1 are stacked in the thickness direction to form a battery pack, the external terminals can be easily removed, and battery 1 is suitable for use as a battery pack.

[0074] (5-5) Variation 5 From the viewpoint of increasing the coefficient of friction between the connecting plate 7 and the insulating plate 6, anti-slip portions may be formed on both the surface of the first insulating portion 61 facing the first connecting portion 71 and the surface of the first connecting portion 71 facing the first insulating portion 61. In this case, the shape of the anti-slip portion of the first insulating portion 61 and the shape of the anti-slip portion of the first connecting portion 71 may be the same or different.

[0075] (5-6) Variation 6 From the viewpoint of increasing the coefficient of friction between the insulating plate 6 and the battery can 4, the first insulating portion 61 may have an anti-slip portion formed on the surface facing the bottom portion 41 of the battery can 4. Furthermore, the bottom portion 41 of the battery can 4 may also have an anti-slip portion formed on the surface facing the first insulating portion 61. The shape of the anti-slip portion formed on the bottom portion 41 may be the same as or different from the shape provided on the first insulating portion 61 or the first connecting portion 71.

[0076] <Conclusion> Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the invention. In particular, the various modifications described herein can be arbitrarily combined as needed. [Explanation of symbols]

[0077] 1:Battery 2: Power generation element 21: Positive electrode 22: Negative electrode 23: Separator 24: End 3: Electrode tabs 31: Positive Tab 32: Negative electrode tab 42a: hole 4: Battery can 41: Bottom 42: Side wall section 42a: hole 43 :Aperture 44: Flange 5: Lid plate 6: Insulating board 61: First insulating section 61a: Uneven shape 62: Second insulating section 62a: hole 7: Connection plate 71: First connection section 72: Second connection section 72a :hole 8: External terminals 81: Large diameter section 82: Spacer

Claims

1. A flat power generation element having multiple positive electrodes, negative electrodes, and separators, An electrode tab including a positive electrode tab electrically connected to or formed integrally with the positive electrode, and a negative electrode tab electrically connected to or formed integrally with the negative electrode, It has a flat, rectangular, shallow-drawn shape with a bottom and side walls rising from the edge of the bottom, and houses the power generation element and the electrode tab in a battery case, A connecting plate connected to either the positive electrode tab or the negative electrode tab, An external terminal that connects to the aforementioned connecting plate and penetrates the aforementioned side wall, An insulating plate is laminated between the battery can and the connecting plate, Equipped with, The aforementioned power generation element is The main surface is housed in the battery can so as to face the bottom, The electrode tab is Protruding from the end of the aforementioned power generation element, The aforementioned connecting plate is A flat plate-shaped first connecting portion is positioned parallel to the bottom and overlaps the bottom, It includes a flat plate-shaped second connecting portion that rises from the edge of the first connecting portion in the same direction as the side wall portion and parallel to the side wall portion, and is connected to the external terminal, battery.

2. The insulating plate is A flat plate-shaped first insulating portion is laminated between the first connecting portion and the bottom portion, The invention includes a flat plate-shaped second insulating portion that rises from the edge of the first insulating portion in the same direction as the side wall portion and is laminated between the second connecting portion and the side wall portion, The battery according to claim 1.

3. The system further includes a cover plate that closes the opening formed at the end of the side wall opposite to the bottom. The battery according to claim 1.

4. At least one of the connecting plate and the insulating plate is Having an anti-slip part, The battery according to claim 1.

5. The aforementioned anti-slip portion is The cross-sectional shape is uneven. The battery according to claim 4.

6. A battery pack comprising a plurality of batteries stacked according to any one of claims 1 to 5.

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