Battery

Abstract

The present invention provides a battery that includes a current collector and an electrode current collector that are well joined together. [Solution] The battery 1 includes a charge / discharge body 10 including, for example, a positive electrode 11 comprising a current collector (for example, a positive electrode current collector foil 11S) and an active material, and a current collector member (for example, a positive electrode current collector plate 21) joined to the positive electrode current collector foil 11S. The positive electrode current collector plate 21 comprises a first rigid portion 21p having a predetermined rigidity and a second rigid portion 21q adjacent to the first rigid portion 21p and having higher rigidity than the first rigid portion 21p. The second rigid portion 21q provided on the positive electrode current collector plate 21 and the positive electrode current collector foil 11S of the positive electrode 11 are joined to each other.

Description

Technical Field

[0001] The present invention relates to a battery.

Background Art

[0002] Conventionally, a current collector member (so-called current collector plate) included in a battery and a current collector of an electrode (so-called current collector foil) are electrically connected by being joined to each other (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the state before being joined, the physical properties such as rigidity of the current collector member and the current collector of the electrode may vary. Therefore, even when the current collector member and the current collector of the electrode are joined based on the same joining conditions in mass production of the battery, if the variation in the physical properties of the current collector member and the current collector of the electrode is relatively large, there is a risk that the current collector member and the current collector of the electrode that are not sufficiently joined will occur.

[0005] That is, among a plurality of current collector members and current collectors of electrodes joined in mass production of the battery, some current collector members and current collectors of electrodes may be peeled off or the joining may become insufficient. It is difficult to maintain the reliability of a battery using such a current collector member and a current collector of an electrode.

Means for Solving the Problems

[0006] The battery of the present invention comprises a charge / discharge body including an electrode comprising a current collector and an active material, and a current collector member joined to the current collector. At least one of the current collector member and the current collector is provided with a first rigid portion having a predetermined rigidity and a second rigid portion adjacent to the first rigid portion and having higher rigidity than the first rigid portion. The second rigid portion provided on at least one of the current collector member and the current collector is joined to the other of the current collector member and the current collector.

[0007] The battery manufacturing method of the present invention is the battery manufacturing method described above. The battery manufacturing method of the present invention has a manufacturing step of stacking and joining the second rigid part provided on at least one of the current collecting member and the current collecting body and the other of the current collecting member and the current collecting body. [Effects of the Invention]

[0008] According to the battery of the present invention, the reliability of the battery can be improved by the current collector and electrode current collector being well-connected. According to the manufacturing method of the battery of the present invention, poor connections between the current collector and the electrode current collector can be suppressed, thereby improving the reliability and productivity of the battery. [Brief explanation of the drawing]

[0009] [Figure 1] A perspective view showing battery 1 of the first embodiment. [Figure 2] An exploded perspective view showing battery 1. [Figure 3] An exploded perspective view showing the components on the positive electrode 11 side of battery 1. [Figure 4] A perspective view showing the charge / discharge unit 10 of battery 1. [Figure 5] A side view showing the junction between the positive electrode current collector foil 11S and the positive electrode current collector plate 21 of the positive electrode 11 in battery 1. [Figure 6] A side view showing a manufacturing process in which a second rigid portion 21q is formed on the positive electrode current collector plate 21 by press-forming the positive electrode current collector plate 21 in a manufacturing method for battery 1. [Figure 7]This side view shows the manufacturing process in which the positive electrode current collector foil 11S of the positive electrode 11 and the second rigid portion 21q of the positive electrode current collector plate 21 are ultrasonically bonded, following the manufacturing process shown in Figure 6. [Figure 8] A side view showing the joint between the positive electrode current collector foil 111S and the positive electrode current collector plate 121 of the positive electrode 111 in the battery 2 of the second embodiment. [Figure 9] A side view showing the joint between the positive electrode current collector foil 111S and the positive electrode current collector plate 21 of the positive electrode 111 in the battery 3 of the third embodiment. [Figure 10] A side view showing the joint between the positive electrode current collector foil 11S and the positive electrode current collector plate 21 of the positive electrode 11 via adhesive 70 in the battery 4 of the fourth embodiment. [Modes for carrying out the invention]

[0010] Each embodiment of the present invention will be described with reference to the drawings. In order to facilitate understanding of each embodiment, the size and proportions of the components may be exaggerated in the drawings. In each embodiment, the same reference numerals are used for the same components, and redundant explanations are omitted. In each embodiment, a left-handed XYZ Cartesian coordinate system is used, with the X, Y, and Z axes as coordinate axes. The arrows on the X, Y, and Z axes indicate the positive direction of the coordinate axis. The X axis is the coordinate axis in the longitudinal direction of the rectangular battery. The Y axis is the coordinate axis in the short direction of the battery. The Z axis is the coordinate axis in the height direction of the battery. However, the positional relationships expressed in the XYZ Cartesian coordinate system are only relative positional relationships.

[0011] [First Embodiment] (Configuration of battery 1 in the first embodiment) The configuration of battery 1 will be explained with reference to Figures 1 to 5.

[0012] As shown in Figures 1 to 5, the battery 1 includes a charge / discharge element 10 for charging and discharging electricity, a current collector 20 connected to the charge / discharge element 10, and an external terminal 30 connected to the current collector 20. The battery 1 also includes an outer casing 40 in which the components of the battery 1 are housed or mounted, an insulator 50 that insulates the components of the battery 1 from the outer casing 40, and a sealant 60 that seals the components of the battery 1 from the outer casing 40.

[0013] The charge / discharge unit 10 charges and discharges electricity. The charge / discharge unit 10 shown in Figures 2, 4, and 5 includes a positive electrode 11, a negative electrode 12, a separator 13, and an electrolyte. As shown in Figures 2 and 4, the charge / discharge unit 10 is constructed by winding together components, each stacked in the order of positive electrode 11, separator 13, negative electrode 12, and separator 13, into a rectangular shape. In the wound charge / discharge unit 10, the separator 13 is positioned as the outermost layer.

[0014] As shown in Figure 4, the positive electrode 11 (electrode) includes a long positive electrode current collector foil 11S (current collector) and a positive electrode active material layer 11T bonded to the positive electrode current collector foil 11S. The positive electrode 11 is wound together with the negative electrode 12 and the separator 13 to form a rectangular prism shape with four corners curved in a convex shape. In the positive electrode 11, negative electrode 12, and separator 13, a pair of ends (thickness portions) exposed to the outside are located at both ends in the longitudinal direction X of the battery 1. A positive electrode current collector portion 11a is provided at one end of the positive electrode current collector foil 11S. The positive electrode current collector portion 11a is bonded to the positive electrode current collector plate 21. As shown in Figures 2 and 5, when the positive electrode current collector portion 11a is wound and bundled, it is compressed in the short direction Y of the battery 1, and the gap is removed. The positive electrode current collector 11a is compressed, but does not need to be plastically deformed. The positive electrode current collector 11a extends along the height direction Z of the battery 1. When the positive electrode current collector 11a is not bundled, its thickness along the short direction Y of the battery 1 is, for example, 0.1 mm to 1.4 mm.

[0015] The positive electrode current collector portion 11a of the positive electrode 11 is formed of, for example, aluminum or an aluminum alloy. The positive electrode active material layer 11T contains a positive electrode active material (active material) composed of a lithium-containing composite oxide, a binder, a conductive assistant, and the like. In the lithium-containing composite oxide, for example, metal elements such as nickel (Ni), cobalt (Co), and manganese (Mn) and lithium (Li) are used.

[0016] As shown in FIG. 4, the negative electrode 12 (electrode) includes an elongated negative electrode current collector foil 12S (current collector) and a negative electrode active material layer 12T joined to the negative electrode current collector foil 12S. A negative electrode current collector portion 12a is provided at one end of the negative electrode current collector foil 12S. The negative electrode current collector portion 12a of the negative electrode current collector foil 12S faces the positive electrode current collector portion 11a of the positive electrode current collector foil 11S along the longitudinal direction X. The negative electrode current collector portion 12a is joined to the negative electrode current collector plate 22. The negative electrode current collector portion 12a is compressed in the short side direction Y of the battery 1 in the wound state, and the gap is removed. The negative electrode current collector portion 12a is compressed, but it does not need to be plastically deformed. The negative electrode current collector portion 12a extends along the height direction Z of the battery 1. In the unbundled state, the thickness of the negative electrode current collector portion 12a along the short side direction Y of the battery 1 is, for example, from 0.05 mm to 0.7 mm.

[0017] The negative electrode current collector portion 12a of the negative electrode 12 is formed of, for example, copper or a copper alloy. The negative electrode active material layer 12T contains a negative electrode active material (active material) composed of a carbon-based material, a binder, a conductive assistant, and the like. For example, graphite is used as the carbon-based material.

[0018] As shown in Figure 4, the separator 13 insulates the positive electrode 11 and the negative electrode 12. The separator 13 is impregnated with an electrolyte. The separator 13 is formed in a long, rectangular shape. The separator 13 is made of a porous material. Polyethylene (pE: polqEthqlene) or polypropylene (pp: polqpropqlene) is used for the separator 13. A heat-resistant insulating material may be used instead of the separator 13. For example, ceramics can be used as the heat-resistant insulating material. This configuration is a so-called separator-less configuration.

[0019] The electrolyte corresponds to what is commonly known as an electrolyte solution. The electrolyte is impregnated into the separator 13. The electrolyte contains an organic solvent, a supporting salt, and additives. For example, a carbonate ester is used as the organic solvent. For example, a lithium salt is used as the supporting salt.

[0020] The current collector 20 is electrically connected to the charge / discharge body 10. The current collector 20 is joined to the current collector foil of the electrode. The current collector 20 shown in Figures 2, 3 and 5 includes a positive electrode current collector plate 21 (current collector) and a negative electrode current collector plate 22 (current collector).

[0021] The positive electrode current collector plate 21 (current collector member) connects the positive electrode current collector foil 11S of the positive electrode 11 to the positive electrode terminal 31. As shown in Figure 3, the positive electrode current collector plate 21 includes a base portion 21a, an insertion hole 21b, and a current collector portion 21c. The base portion 21a is formed in a plate shape and is joined to the positive electrode terminal 31. The insertion hole 21b penetrates the base portion 21a. The insertion portion 31b of the positive electrode terminal 31 is inserted into the insertion hole 21b. The current collector portion 21c is formed in a longer shape than the base portion 21a and extends from the base portion 21a toward the charge / discharge body 10. The current collector portion 21c is bent along the outer shape of the positive electrode current collector portion 11a of the positive electrode 11. The positive electrode current collector plate 21 is formed of, for example, aluminum or an aluminum alloy.

[0022] As shown in Figures 2, 3, and 5, the positive electrode current collector plate 21 includes a first rigid portion 21p and a second rigid portion 21q in the current collector portion 21c. The current collector portion 21c has a thickness along the short-side direction Y of the battery 1, for example, from 0.5 mm to 3 mm. The first rigid portion 21p has a predetermined rigidity. The second rigid portion 21q is adjacent to the first rigid portion 21p along the height direction Z of the battery 1 and has higher rigidity than the first rigid portion 21p. As shown in Figure 5, in the direction along the short-side direction Y of the battery 1, the second thickness t2 of the second rigid portion 21q is thinner than the first thickness t1 of the first rigid portion 21p. The second rigid portion 21q is formed, for example, by cold working, which causes plastic deformation of the portion of the positive electrode current collector plate 21 adjacent to the first rigid portion 21p. The thickness of the second rigid portion 21q is equivalent to the thickness of the first rigid portion 21p in the state before cold working. In other words, the second rigid portion 21q is rolled from a first thickness t1 to a second thickness t2 during cold working.

[0023] Here, stiffness refers to the hardness of an object. Stiffness is defined by hardness measured by methods such as the Vickers hardness test or the stress-strain curve measured by the tensile test. The Vickers hardness test is specified, for example, in JIS Z 2244. The stress-strain curve represents the hardness of an object based on Young's modulus. The smaller the Young's modulus, the higher the hardness of the object.

[0024] As shown in Figure 5, the second rigid portion 21q of the positive electrode current collector plate 21 is joined to the positive electrode current collector foil 11S of the positive electrode 11. The joining portion 21r included in the second rigid portion 21q is joined to the positive electrode current collector foil 11S. The joining portion 21r is joined to the positive electrode current collector foil 11S by ultrasonic waves. As shown in Figure 5, the second thickness t2 of the second rigid portion 21q is greater than the third thickness t3 of at least one positive electrode current collector foil 11S. The third thickness t3 is the thickness of at least one positive electrode current collector foil 11S among a bundle of multiple positive electrode current collector foils 11S.

[0025] The negative electrode current collector plate 22 (current collector member) connects the negative electrode current collector foil 12S of the negative electrode 12 with the negative electrode terminal 32. The shape of the negative electrode current collector plate 22 corresponds to the shape of the positive electrode current collector plate 21, inverted in the height direction Z, with the center of the longitudinal direction X of the battery 1 as the reference point. The negative electrode current collector plate 22, like the positive electrode current collector plate 21, includes a base, an insertion hole, and a current collector portion. The base is formed in a plate shape and is joined to the negative electrode terminal 32. The insertion hole penetrates the base. The insertion portion of the negative electrode terminal 32 is inserted into the insertion hole. The current collector portion is formed in a longer shape than the base and extends from the base toward the charge / discharge body 10. The current collector portion is bent along the outer shape of the negative electrode current collector portion 12a of the negative electrode 12. The negative electrode current collector plate 22 is made of, for example, copper or a copper alloy.

[0026] As shown in Figure 2, the negative electrode current collector plate 22 is provided with a first rigid portion 22p and a second rigid portion 22q in the current collection portion 22c. The first rigid portion 22p has a predetermined rigidity. The second rigid portion 22q is adjacent to the first rigid portion 22p along the height direction Z of the battery 1 and has higher rigidity than the first rigid portion 22p. The second rigid portion 22q is thinner than the first rigid portion 22p. The second rigid portion 22q is formed, for example, by cold working, which causes plastic deformation of the portion of the negative electrode current collector plate 22 adjacent to the first rigid portion 22p. The thickness of the second rigid portion 22q is the same as the thickness of the first rigid portion 22p in the state before cold working. That is, the second rigid portion 22q is rolled from the first thickness to the second thickness during cold working.

[0027] The second rigid portion 22q of the negative electrode current collector plate 22 is joined to the negative electrode current collector foil 12S of the negative electrode 12. The joining portion 22r included in the second rigid portion 22q is joined to the negative electrode current collector foil 12S. The joining portion 22r is joined to the negative electrode current collector foil 12S by ultrasonic waves. The second thickness of the second rigid portion 22q is greater than the third thickness of at least one negative electrode current collector foil 12S. The third thickness is the thickness of at least one negative electrode current collector foil 12S among a bundle of multiple negative electrode current collector foils 12S.

[0028] The external terminal 30 is connected to the current collector 20. The external terminal 30 shown in Figures 1 to 3 includes a positive terminal 31 and a negative terminal 32.

[0029] The positive terminal 31 is connected to the positive current collector plate 21. As shown in Figure 3, the positive terminal 31 includes a rectangular plate-shaped base portion 31a, a cylindrical insertion portion 31b protruding downward from the base portion 31a, and a cylindrical joint portion 31c protruding downward from the periphery of the base portion 31a.

[0030] The base 31a of the positive terminal 31 is in contact with the base 54a of the positive side second insulating plate 54. The insertion portion 31b is inserted into the insertion hole 54b of the positive side second insulating plate 54, the positive side insertion hole 42a of the cover 42, the insertion hole 52b of the positive side first insulating plate 52, and the insertion hole 21b of the positive current collector plate 21. The joint portion 31c protrudes downward from the insertion hole 21b of the positive current collector plate 21 and is expanded radially outward to join with the positive current collector plate 21. That is, the joint portion 31c is crimped to the periphery of the insertion hole 21b of the positive current collector plate 21. Furthermore, the joint portion 31c is welded to the periphery of the insertion hole 21b of the positive current collector plate 21. The positive terminal 31 is formed of, for example, aluminum or an aluminum alloy.

[0031] The negative terminal 32 is connected to the negative current collector plate 22. The shape of the negative terminal 32 corresponds to the shape of the positive terminal 31, inverted with respect to the center of the longitudinal direction X of the battery 1, with respect to the height direction Z. Similar to the positive terminal 31, the negative terminal 32 includes a rectangular plate-shaped base, a cylindrical insertion part protruding downward from the base, and a cylindrical joint part protruding downward from the periphery of the base.

[0032] The base of the negative electrode terminal 32 is in contact with the base of the negative electrode side second insulating plate 55. The insertion portion is inserted into the insertion hole of the negative electrode side second insulating plate 55, the negative electrode side insertion hole of the cover 42, the insertion hole of the negative electrode side first insulating plate, and the insertion hole of the negative electrode current collector plate 22. The joint portion protrudes downward from the insertion hole of the negative electrode current collector plate 22 and is expanded radially outward to join with the negative electrode current collector plate 22. That is, the joint portion is crimped to the periphery of the insertion hole of the negative electrode current collector plate 22. Furthermore, the joint portion is welded to the periphery of the insertion hole of the negative electrode current collector plate 22. The negative electrode terminal 32 is made of, for example, copper or a copper alloy.

[0033] The outer casing 40 houses or mounts the components of the battery 1. The outer casing 40 shown in Figures 1 to 3 includes a container 41, a lid 42, and a sealing plug 43.

[0034] As shown in Figure 2, the container 41 houses the charge / discharge unit 10, etc., which is covered by an insulating cover 51. The container 41 is made of a rectangular metal can. The container 41 includes an opening 41a that opens in the height direction Z and a housing section 41b that is connected to the opening 41a. The container 41 is made of, for example, aluminum or an aluminum alloy.

[0035] As shown in Figures 1 and 2, the lid 42 seals the opening 41a of the container 41. The lid 42 is formed from a long, plate-shaped metal sheet. As shown in Figure 3, the lid 42 has a positive electrode insertion hole 42a, which is a circular through-hole, at one end in the longitudinal direction X. The insertion portion 31b of the positive electrode terminal 31 is inserted into the positive electrode insertion hole 42a. The lid 42 has a negative electrode insertion hole, which is a circular through-hole, at the other end in the longitudinal direction X. The insertion portion of the negative electrode terminal 32 is inserted into the negative electrode insertion hole. Between the positive electrode insertion hole 42a and the negative electrode insertion hole, the lid 42 has an injection hole, which is a circular through-hole. The electrolyte is injected from the lid 42 towards the container 41 through the injection hole. A sealing plug 43 is inserted into the injection hole. As shown in Figure 1, the lid 42 is equipped with a cleavage valve 42c in the center in the longitudinal direction X. The lid 42 is formed of, for example, aluminum or an aluminum alloy.

[0036] The sealing plug 43 seals the liquid injection hole of the lid 42, as shown in Figures 1 and 2. The sealing plug 43 is welded to the lid 42. The sealing plug 43 is made of, for example, aluminum or an aluminum alloy.

[0037] The insulator 50 insulates the components of the battery 1 from the outer casing 40. The insulator 50 shown in Figures 1 to 3 includes an insulating cover 51, a positive electrode side first insulating plate 52, a negative electrode side first insulating plate, a positive electrode side second insulating plate 54, and a negative electrode side second insulating plate 55.

[0038] As shown in Figure 2, the insulating cover 51 covers the charge / discharge element 10, insulating the charge / discharge element 10 from the container 41. The insulating cover 51 is formed from a polyhedral sheet. The insulating cover 51 is folded into a box shape to form a pentahedron. The insulating cover 51 has an opening in the part facing the lid 42. The insulating cover 51 is made of, for example, polypropylene.

[0039] As shown in Figure 3, the positive electrode side first insulating plate 52 insulates the positive electrode current collector plate 21 from the cover 42. The positive electrode side first insulating plate 52 includes a rectangular plate-shaped base portion 52a, an insertion hole 52b that penetrates the base portion 52a, and a protrusion 52c that surrounds the side edge of the base portion 52a in an annular shape and protrudes away from the cover 42. The positive electrode current collector plate 21 is housed in the space formed by the base portion 52a and the protrusion 52c of the positive electrode side first insulating plate 52. The insertion portion 31b of the positive electrode terminal 31 is inserted into the insertion hole 52b. The positive electrode side first insulating plate 52 is formed of, for example, an insulating resin.

[0040] The negative electrode side first insulating plate insulates the negative electrode current collector plate 22 from the cover 42. The shape of the negative electrode side first insulating plate corresponds to the shape of the positive electrode side first insulating plate 52, inverted in the height direction Z, with the center of the longitudinal direction X of the battery 1 as the reference point. Similar to the positive electrode side first insulating plate 52, the negative electrode side first insulating plate includes a rectangular plate-shaped base, an insertion hole penetrating the base, and a protrusion that surrounds the side edge of the base in an annular shape and protrudes away from the cover 42. The negative electrode current collector plate 22 is housed in the space formed by the base and the protrusion of the negative electrode side first insulating plate. The insertion portion of the negative electrode terminal 32 is inserted into the insertion hole. The negative electrode side first insulating plate is formed of, for example, an insulating resin.

[0041] As shown in Figure 3, the positive electrode side second insulating plate 54 insulates the positive electrode terminal 31 from the cover 42. The positive electrode side second insulating plate 54 includes a rectangular plate-shaped base portion 54a, an insertion hole 54b that penetrates the base portion 54a, and a protrusion 54c that surrounds the side edge of the base portion 54a in an annular shape and protrudes away from the cover 42. The positive electrode terminal 31 is housed in the space formed by the base portion 54a and the protrusion 54c of the positive electrode side second insulating plate 54. The insertion portion 31b of the positive electrode terminal 31 is inserted into the insertion hole 54b. The positive electrode side second insulating plate 54 is formed of, for example, an insulating resin.

[0042] The negative electrode side second insulating plate 55 insulates the negative electrode terminal 32 from the cover 42. The shape of the negative electrode side second insulating plate 55 corresponds to the shape of the positive electrode side second insulating plate 54, inverted in the height direction Z, with the center of the longitudinal direction X of the battery 1 as the boundary. Similar to the positive electrode side second insulating plate 54, the negative electrode side second insulating plate 55 includes a rectangular plate-shaped base, an insertion hole penetrating the base, and a protrusion that surrounds the side edge of the base in an annular shape and protrudes away from the cover 42. The negative electrode terminal 32 is housed in the space formed by the base and the protrusion of the negative electrode side second insulating plate 55. The insertion portion of the negative electrode terminal 32 is inserted into the insertion hole. The negative electrode side second insulating plate 55 is formed of, for example, an insulating resin.

[0043] The sealant 60 seals the components of the battery 1 and the outer casing 40. The sealant 60 shown in Figure 3 includes a positive electrode gasket 61 and a negative electrode gasket.

[0044] As shown in Figure 3, the positive electrode gasket 61 insulates the positive electrode second insulating plate 54 from the lid 42. The positive electrode gasket 61 is formed in a cylindrical shape. The positive electrode gasket 61 includes a first insertion portion 61a with a relatively large outer diameter, a second insertion portion 61b that is continuous with the first insertion portion 61a and has a relatively smaller outer diameter, and an insertion hole 61c that penetrates the first insertion portion 61a and the second insertion portion 61b. The first insertion portion 61a of the positive electrode gasket 61 is inserted into the insertion hole 54b of the positive electrode second insulating plate 54. The second insertion portion 61b of the positive electrode gasket 61 is inserted into the positive electrode insertion hole 42a of the lid 42. The insertion portion 31b of the positive electrode terminal 31 is inserted into the insertion hole 61c. The positive electrode gasket 61 is formed of, for example, rubber that has insulating and elastic properties.

[0045] The negative electrode gasket insulates the negative electrode second insulating plate 55 from the lid 42. The shape of the negative electrode gasket corresponds to the shape of the positive electrode gasket 61 inverted in the height direction Z, with the center of the longitudinal direction X of the battery 1 as the reference point. Similar to the positive electrode gasket 61, the negative electrode gasket includes a first insertion portion with a relatively large outer diameter, a second insertion portion that is continuous with the first insertion portion and has a relatively smaller outer diameter, and an insertion hole that penetrates the first and second insertion portions. The first insertion portion of the negative electrode gasket is inserted into the insertion hole of the negative electrode second insulating plate 55. The second insertion portion of the negative electrode gasket is inserted into the negative electrode insertion hole of the lid 42. The insertion portion of the negative electrode terminal 32 is inserted into the insertion hole. The negative electrode gasket is formed of, for example, rubber that has insulating and elastic properties.

[0046] (Method for manufacturing battery 1 of the first embodiment) The manufacturing method for battery 1 will be described with reference to Figures 6 and 7. Of the manufacturing methods for battery 1, the manufacturing method specific to battery 1 of the first embodiment will be described.

[0047] (Pressing in the manufacturing process) FIG. 6 shows a manufacturing process in which the second rigid portion 21q of the positive current collector plate 21 is formed by pressing the positive current collector plate 21. In this manufacturing process, for example, the second rigid portion 21q is formed by pressing a region adjacent to the first rigid portion 21p of the positive current collector plate 21. The rigidity of the second rigid portion 21q formed by pressing is higher than that of the first rigid portion 21p due to work hardening. In this manufacturing process, the press 102 is brought closer to the stage 101 on which the positive current collector plate 21 is placed, and a region adjacent to the first rigid portion 21p of the positive current collector plate 21 is partially rolled by the press 102. The pressing force P1 input from the press 102 to the positive current collector plate 21 forms the second rigid portion 21q on the positive current collector plate 21. That is, the second rigid portion 21q is formed in a region adjacent to the first rigid portion 21p of the positive current collector plate 21 by cold working. In this manufacturing process, by pressing the positive current collector plate 21, the reduction rate S of the thickness of the region of the second rigid portion 21q is set to 0% < S ≦ 10%. As shown in FIG. 5, the second thickness t2 of the second rigid portion 21q is at most 10% thinner than the first thickness t1 of the first rigid portion 21p.

[0048] (Ultrasonic bonding in the manufacturing process) FIG. 7 shows a manufacturing process in which the positive current collector foil 11S of the positive electrode 11 and the second rigid portion 2lq of the positive current collector plate 21 are ultrasonically bonded following the cold working manufacturing process shown in FIG. 6. In this manufacturing process, the positive current collector foil 11S and the second rigid portion 21q are sandwiched between the horn 103 and the anvil 104. The ultrasonic wave P2 input from the horn 103 to the positive current collector foil 11S ultrasonically bonds the positive current collector foil 11S and the second rigid portion 21q.

[0049] (Effects of the battery 1 and the manufacturing method of the battery 1 according to the first embodiment) The effects of the battery 1 and the manufacturing method of the battery 1 will be described.

[0050] The effects of the battery 1 and the manufacturing method of the battery 1 will be described with respect to the positive electrode 11 side. In the first embodiment, the effects on the negative electrode 12 side are the same as those on the positive electrode 11 side. Therefore, the description of the negative electrode 12 side will be omitted.

[0051] In battery 1, as shown in Figure 5, the positive electrode current collector plate 21 comprises a first rigid portion 21p having a predetermined rigidity and a second rigid portion 21q adjacent to the first rigid portion 21p and having higher rigidity than the first rigid portion 21p. The second rigid portion 21q of the positive electrode current collector plate 21 and the positive electrode current collector foil 11S of the positive electrode 11 are joined to each other. The manufacturing method of battery 1 includes a manufacturing step of joining the second rigid portion 21q of the positive electrode current collector plate 21 and the positive electrode current collector foil 11S of the positive electrode 11 to each other, as shown in Figure 7.

[0052] With this configuration, a second rigid portion 21q can be formed by partially increasing the rigidity of the positive electrode current collector plate 21 before joining the positive electrode current collector foil 11S, thereby suppressing variations in the physical properties of the second rigid portion 21q. By suppressing variations in the physical properties of the positive electrode current collector plate 21, the proportion of positive electrode current collector plates 21 and positive electrode current collector foil 11S that meet predetermined joining conditions in mass production can be relatively increased. The joining conditions are those that allow the positive electrode current collector plate 21 and positive electrode current collector foil 11S to be sufficiently joined. Therefore, it is possible to reduce the instances in which the positive electrode current collector plate 21 and positive electrode current collector foil 11S are not sufficiently joined and peel off due to failure to meet the joining conditions optimized based on predetermined specifications. As a result, the yield of the positive electrode current collector plate 21 and the charge / discharge unit 10 including the positive electrode 11 can be improved. Specifically, it is possible to suppress poor conductivity (open circuits) caused by the separation of the second rigid part 21q of the positive electrode current collector plate 21 and the positive electrode current collector foil 11S after they have been joined. Furthermore, it is possible to suppress the increase in electrical resistance caused by insufficient bonding between the second rigid part 21q of the positive electrode current collector plate 21 and the positive electrode current collector foil 11S after they have been joined. Insufficient bonding means that the second rigid part 21q of the positive electrode current collector plate 21 and the positive electrode current collector foil 11S are partially separated.

[0053] Therefore, with battery 1, the reliability of battery 1 can be improved by the well-bonded positive electrode current collector plate 21 and the positive electrode current collector foil 11S of the positive electrode 11. Furthermore, with the manufacturing method of battery 1, poor bonding between the positive electrode current collector plate 21 and the positive electrode current collector foil 11S of the positive electrode 11 can be suppressed, thereby improving the reliability and productivity of battery 1. Moreover, with this configuration, variations in the physical properties of the positive electrode current collector plate 21 can be suppressed, so inexpensive materials with large variations in physical properties can be used.

[0054] The joining portion 21r, which is included in the second rigid portion 21q of the positive electrode current collector plate 21, and the positive electrode current collector foil 11S are joined to each other. As shown in Figure 5, the joining portion 21r is included in the second rigid portion 21q and constitutes most of the second rigid portion 21q. In principle, the joining portion 21r can constitute the entirety of the second rigid portion 21q. However, when ultrasonically joining the positive electrode current collector plate 21 and the positive electrode current collector foil 11S of the positive electrode 11, it is desirable to configure the joining portion 21r as the portion of the second rigid portion 21q excluding the outer edge, considering the stable propagation of ultrasonic energy to the joining portion. Also, when laser welding the positive electrode current collector plate 21 and the positive electrode current collector foil 11S of the positive electrode 11, it is desirable to configure the joining portion 21r as the portion of the second rigid portion 21q excluding the outer edge, considering the prevention of laser light leakage to the surrounding area of ​​the welded portion. Furthermore, when crimping the positive electrode current collector plate 21 and the positive electrode current collector foil 11S of the positive electrode 11, it is desirable to configure the portion excluding the outer edge of the second rigid part 21q as the joint part 21r, considering the prevention of excessive strain at the joint. When manufacturing is carried out in ultrasonic bonding, laser welding, or crimp bonding taking the above into consideration, the first rigid part 21p, the second rigid part 21q, and the joint part 21r included in the second rigid part 21q will exist after the positive electrode current collector plate 21 and the positive electrode current collector foil 11S of the positive electrode 11 are joined.

[0055] The positive electrode current collector plate 21 and the positive electrode current collector foil 11S are joined by ultrasonic waves. In the manufacturing process, as shown in Figure 7, the positive electrode current collector plate 21 and the positive electrode current collector foil 11S are joined by ultrasonic waves. Compared to thermal welding and laser welding, ultrasonic bonding makes it easier for the positive electrode current collector plate 21 and the positive electrode current collector foil 11S to stretch in a direction intersecting the lamination direction. However, since the rigidity of the second rigid part 21q of the positive electrode current collector plate 21 is relatively high, stretching in a direction intersecting the lamination direction can be suppressed. By suppressing the stretching of the positive electrode current collector plate 21 and the positive electrode current collector foil 11S in a direction intersecting the lamination direction during ultrasonic bonding, the ultrasonic energy input to the positive electrode current collector plate 21 and the positive electrode current collector foil 11S is easily absorbed by the positive electrode current collector plate 21 and the positive electrode current collector foil 11S. As a result, the positive electrode current collector plate 21 and the positive electrode current collector foil 11S are easily joined. Therefore, even when ultrasonic bonding is used, the second rigid portion 21q of the positive electrode current collector plate 21 and the positive electrode current collector foil 11S can be sufficiently bonded. In ultrasonic bonding, the yield of the positive electrode current collector plate 21 and the charge / discharge body 10 including the positive electrode 11 can be improved.

[0056] As shown in Figure 5, in the positive electrode current collector plate 21, the second thickness t2 of the second rigid portion 21q is thinner than the first thickness t1 of the first rigid portion 21p in the short-side direction Y of the battery. In the manufacturing process, as shown in Figure 6, the second rigid portion 21q is formed by pressing a part of the positive electrode current collector plate 21. The rigidity of the second rigid portion 21q becomes higher than that of the first rigid portion 21p due to cold working by pressing. With this configuration, the second rigid portion 21q can be formed in the positive electrode current collector plate 21 by pressing only the second rigid portion 21q to make it thinner, starting from a state where the thicknesses of the first rigid portion 21p and the second rigid portion 21q are equal. Therefore, the rigidity of the second rigid portion 21q can be improved to be higher than that of the first rigid portion 21p while easily forming the second rigid portion 21q.

[0057] As shown in Figure 6, the second rigid portion 21q of the positive electrode current collector plate 21 is formed by plastic deformation of the positive electrode current collector plate 21. That is, the second rigid portion 21q can be formed by cold working. With this configuration, the second rigid portion 21q can be easily formed. The plastic deformation of the second rigid portion 21q is performed, for example, by general-purpose press forming. Cold working by press forming makes it easy to reduce variations in processing, so the rigidity of the second rigid portion 21q can be improved with high precision.

[0058] As shown in Figure 5, the second thickness t2 of the second rigid portion 21q of the positive electrode current collector plate 21 is greater than the third thickness t3 of the positive electrode current collector foil 11S joined to the second rigid portion 21q. The third thickness t3 is the thickness of at least one of the bundled positive electrode current collector foils 11S. With this configuration, the second rigid portion 21q, which is plastically deformed to increase rigidity, is formed on the positive electrode current collector plate 21, which is thicker than the positive electrode current collector foil 11S. Since the positive electrode current collector plate 21 is thicker than the positive electrode current collector foil 11S, the occurrence of wrinkles and distortions can be sufficiently suppressed compared to the positive electrode current collector foil 11S. For this reason, press forming of the positive electrode current collector plate 21 is easier than press forming of the positive electrode current collector foil 11S. Consequently, the second rigid portion 21q can be formed more easily on the positive electrode current collector plate 21 than on the positive electrode current collector foil 11S.

[0059] The first and second rigid parts may be provided on at least one of the electrodes, either the positive electrode 11 or the negative electrode 12. The second rigid part 21q may be provided only on the positive electrode 11. Aluminum has a greater rate of rigidity improvement due to work hardening compared to copper. For this reason, the positive electrode current collector plate 21 containing aluminum has a greater effect of rigidity improvement due to work hardening compared to the negative electrode current collector foil 12S of the negative electrode 12 containing copper. Therefore, by providing the second rigid part 21q only on the positive electrode 11 side, where the effect of rigidity improvement due to work hardening is relatively greater, peeling of the positive electrode current collector plate 21 and the positive electrode current collector foil 11S can be suppressed.

[0060] In the manufacturing process, for example, the rigidity is determined by Vickers hardness or Young's modulus. According to such a configuration, the rigidity can be determined by a universal coefficient such as Vickers hardness or Young's modulus. Therefore, the rigidity of the second rigid portion 21q of the positive electrode current collector plate 21 can be accurately determined.

[0061] In the manufacturing process, as shown in FIG. 6, by pressing the second rigid portion 21q of the positive electrode current collector plate 21, the reduction rate S of the thickness of the second rigid portion 21q is set to 0% < S ≦ 10%. According to such a configuration, the rigidity of the second rigid portion 21q of the positive electrode current collector plate 21 can be sufficiently increased. Specifically, for example, when cold working by rolling is performed on aluminum contained in the positive electrode current collector plate 21 so that the thickness is reduced by 3%, the hardness (rigidity) defined by Vickers hardness can be relatively increased by about 25%. Here, when the thickness of aluminum is reduced by 3%, the Young's modulus can be reduced by about 5%. Similarly, when the thickness of aluminum is reduced by 5%, the Vickers hardness can be relatively increased by about 35%. Similarly, when the thickness of aluminum is reduced by 10%, the Vickers hardness can be relatively increased by about 50%.

[0062] [Second Embodiment] In the second embodiment, the positive electrode 111 side will be described. In the second embodiment, the configuration and effects on the negative electrode side are the same as those on the positive electrode 111 side. Therefore, the description of the negative electrode side is omitted.

[0063] (Configuration of Battery 2 in the Second Embodiment) The configuration of the battery 2 in the second embodiment will be described with reference to FIG. 8.

[0064] Unlike the battery 1 of the first embodiment, the battery 2 of the second embodiment has a first rigid part 111p and a second rigid part 111q provided on the positive electrode current collector foil 111S of the positive electrode 111. The positive electrode 111 has the same configuration as the positive electrode 11 except that the positive electrode current collector foil 111S is provided with a second rigid part 111q and a connecting part 111r. The positive electrode current collector plate 121 has the same configuration as the positive electrode current collector plate 21 except that it is not provided with a second rigid part. In the battery 2 of the second embodiment, the same reference numerals are used for components that are the same as those in the battery 1 of the first embodiment, and their descriptions are omitted.

[0065] As shown in Figure 8, the positive electrode current collector foil 111S includes a first rigid portion 111p and a second rigid portion 111q. The first rigid portion 111p has a predetermined rigidity. The second rigid portion 111q is adjacent to the first rigid portion 111p along the height direction Z of the battery 2 and has higher rigidity than the first rigid portion 111p. In the direction along the short direction Y of the battery 2, the second thickness t5 of the second rigid portion 111q is thinner than the first thickness t4 of the first rigid portion 111p. The second rigid portion 111q is formed, for example, by cold working, which causes plastic deformation in the portion adjacent to the positive electrode current collector plate 121. The thickness of the second rigid portion 111q is the same as the thickness of the first rigid portion 111p before cold working. That is, the second rigid portion 111q is rolled from a first thickness t4 to a second thickness t5 during cold working.

[0066] The second rigid portion 111q of the positive electrode current collector foil 111S is joined to the current collector portion 121c of the positive electrode current collector plate 121. The joining portion 111r included in the second rigid portion 111q is joined to the current collector portion 121c of the positive electrode current collector plate 121. The joining portion 111r is joined to the positive electrode current collector plate 121 by ultrasonic waves.

[0067] (Method for manufacturing battery 2 of the second embodiment) In the conventional manufacturing method of battery 2, with the positive electrode 111, separator 13, and negative electrode 12 wound together, the bundled positive electrode current collector portion 111a is compressed in the short-side direction Y of battery 1, removing any gaps. At this time, if the positive electrode current collector portion 111a is pressed in such a way that it is partially plastically deformed, a second rigid portion 111q can be formed on the positive electrode current collector foil 111S. The portion of the positive electrode current collector portion 111a that is not plastically deformed corresponds to the first rigid portion 111p.

[0068] Specifically, the mold that compresses the bundled positive electrode current collector 111a shown in Figure 4 by sandwiching it along the short-side direction Y of the battery 1 has two convex sections. In the mold, a relatively protruding section and a relatively non-protruding section are provided along the height direction Z of the battery 1, thereby creating two convex sections. The relatively protruding section of the convex section compresses and plastically deforms the positive electrode current collector 111a to form a second rigid section 111q. At the same time, the relatively non-protruding section of the convex section compresses the positive electrode current collector 111a only to form a first rigid section 111p. Specifically, the positive electrode current collector 111a is processed from the wound and bundled state shown in Figure 4 to the compressed state along the short-side direction Y of the battery 1 shown in Figure 2. At this time, the positive electrode current collector 111a has a second rigid section 111q formed by the relatively protruding section of the mold's convex section. At the same time, a first rigid portion 111p is formed on the positive electrode current collector portion 111a by the relatively non-protruding portion of the mold's convex part.

[0069] Alternatively, the positive electrode current collector portion 111a, which is in a straight line, may be partially plastically deformed to form a second rigid portion 111q, and then the positive electrode current collector portion 111a, which is in a wound and bundled state, may be compressed.

[0070] In this manufacturing process, the joint portion 111r of the positive electrode current collector foil 111S and the positive electrode current collector plate 121 are joined by ultrasonic waves.

[0071] The method for manufacturing battery 2, other than those described above, is the same as the method for manufacturing battery 1 in the first embodiment.

[0072] (Effects of the battery 2 and the manufacturing method of the battery 2 according to the second embodiment) The effects of battery 2 and the manufacturing method for battery 2 will be explained.

[0073] In battery 2, a second rigid portion 111q is provided on the positive electrode current collector foil 111S. With battery 2, the reliability of battery 2 can be improved by the well-bonded positive electrode current collector plate 121 and the second rigid portion 111q of the positive electrode current collector foil 111S. Furthermore, the manufacturing method of battery 2 can suppress bonding defects between the positive electrode current collector plate 121 and the positive electrode 111, thereby improving the reliability and productivity of battery 2. Moreover, with this configuration, variations in the physical properties of the positive electrode current collector foil 111S can be suppressed, so inexpensive materials with large variations in physical properties can be used.

[0074] [Third Embodiment] In the third embodiment, the positive electrode 111 will be described. In the third embodiment, the configuration and effects of the negative electrode are the same as those of the positive electrode 111. Therefore, the description of the negative electrode will be omitted.

[0075] (Configuration of battery 3 in the third embodiment) The configuration of the battery 3 in the third embodiment will be described with reference to Figure 9.

[0076] In the third embodiment of battery 3, the positive electrode current collector plate 21 in the first embodiment and the positive electrode current collector foil 111S of the positive electrode 111 in the second embodiment are joined together. In the third embodiment of battery 3, the same reference numerals are used for components that are the same as those in the first embodiment of battery 1 or the second embodiment of battery 2, and their descriptions are omitted.

[0077] As shown in Figure 9, the joint portion 111r included in the second rigid portion 111q of the positive electrode current collector foil 111S and the second rigid portion 21q of the positive electrode current collector plate 21 are laminated and joined together.

[0078] (Method for manufacturing battery 3 of the third embodiment) In the manufacturing method of the battery 3, for example, the joint portion 111r of the positive electrode current collector foil 111S and the second rigid portion 21q of the positive electrode current collector plate 21 are joined together.

[0079] The manufacturing method for battery 3, other than those described above, is the same as the manufacturing method for battery 1 in the first embodiment and battery 2 in the second embodiment.

[0080] (Effects of the battery 3 and the manufacturing method of the battery 3 according to the third embodiment) The effects of battery 3 and the manufacturing method for battery 3 will be explained.

[0081] In battery 3, the positive electrode current collector plate 21 is provided with a second rigid portion 21q. Furthermore, in battery 3, the positive electrode current collector foil 111S is provided with a second rigid portion 111q. With battery 3, the reliability of battery 3 can be improved by the sufficiently bonded second rigid portion 111q of the positive electrode current collector plate 21 and the second rigid portion 111q of the positive electrode current collector foil 111S. In addition, the manufacturing method of battery 3 can suppress bonding defects between the positive electrode current collector plate 21 and the positive electrode 111, thereby improving the reliability and productivity of battery 3. Moreover, with this configuration, variations in the physical properties of the positive electrode current collector plate 21 and the positive electrode current collector foil 111S can be suppressed, allowing the use of inexpensive materials with large variations in physical properties.

[0082] [Fourth Embodiment] In the fourth embodiment, the positive electrode 11 will be described. In the fourth embodiment, the configuration and effects of the negative electrode are the same as those of the positive electrode 11. Therefore, the description of the negative electrode will be omitted.

[0083] (Configuration of battery 4 in the fourth embodiment) The configuration of the battery 4 in the fourth embodiment will be described with reference to Figure 10.

[0084] In the fourth embodiment, unlike the battery 1 of the first embodiment, the positive electrode current collector foil 11S and the positive electrode current collector plate 21 are joined together via a conductive adhesive 70 (adhesive member). In the fourth embodiment, the same components as in the first embodiment of the battery 1 are given the same reference numerals, and their descriptions are omitted.

[0085] The joint portion 21r of the positive electrode current collector plate 21 and the positive electrode current collector foil 11S are laminated and joined via an adhesive 70, as shown in Figure 10. The adhesive 70 is conductive. The adhesive 70 is composed of, for example, a thermosetting resin containing conductive particles. For example, epoxy or acrylic is used for the resin. For example, gold, silver, copper, aluminum, nickel, or carbon is used for the particles.

[0086] (Method for manufacturing the battery 4 of the fourth embodiment) In the manufacturing method of the battery 4, for example, the positive electrode current collector foil 11S of the positive electrode 11 and the joint portion 21r of the positive electrode current collector plate 21 are joined via an adhesive 70. Specifically, after laminating the positive electrode current collector foil 11S and the positive electrode current collector plate 21 via the adhesive 70, at least one of the positive electrode current collector foil 11S or the positive electrode current collector plate 21 is heated to heat-cur the adhesive 70.

[0087] The manufacturing method for battery 4, other than those described above, is the same as the manufacturing method for battery 1 in the first embodiment. The manufacturing method for battery 4 in the fourth embodiment may also be applied to the manufacturing method for battery 2 in the second embodiment or the manufacturing method for battery 3 in the third embodiment.

[0088] (Effects of the battery 4 and the manufacturing method of the battery 4 according to the fourth embodiment) The effects of battery 4 and the manufacturing method of battery 4 will be explained.

[0089] In battery 4, the positive electrode current collector plate 21 is provided with a second rigid portion 21q. Furthermore, in battery 4, the second rigid portion 21q of the positive electrode current collector plate 21 and the positive electrode current collector foil 11S are joined via a conductive adhesive 70. That is, the configuration is not limited to directly joining the positive electrode current collector plate 21 and the positive electrode current collector foil 11S, but can also be joined indirectly via the adhesive 70. The adhesive 70 of battery 4 in the fourth embodiment may also be applied to battery 2 in the second embodiment or battery 3 in the third embodiment.

[0090] [Other embodiments] The battery of the present invention is not limited to the configuration described in the embodiments, but can be appropriately configured based on the content described in the claims.

[0091] The joining of the current collector member and the current collector in this invention is not limited to ultrasonic bonding. The joining of the current collector member and the current collector in this invention can be performed by laser welding, crimping, or thermal welding.

[0092] The battery of the present invention is not limited to lithium-ion batteries. The battery of the present invention can be applied to, for example, nickel-metal hydride batteries and lead-acid batteries. The battery of the present invention is not limited to secondary batteries. The battery of the present invention can be applied to primary batteries. The battery of the present invention is not limited to a configuration in which the charge / discharge unit is sealed by a container and a lid. The battery of the present invention can be applied to a configuration in which the charge / discharge unit is sealed by a laminate film. Each embodiment is described in detail or in a simplified manner to illustrate the present invention, and it is not necessary to have all the described configurations, or it may have configurations that are not shown. Also, some of the configurations of one embodiment may be deleted, replaced with configurations of other embodiments, or combined with configurations of other embodiments. [Explanation of Symbols]

[0093] 1,2,3,4 Battery, 10 Charge / Discharge Element, 11 Positive Electrode, 11S Positive Electrode Foil (Current Collector), 12 Negative Electrode, 12S Negative Electrode Foil (Current Collector), 21 Positive Electrode Plate (Current Collector), 21p First Rigid Part, 21q Second Rigid Part, 21r Joint, 22 Negative Electrode Plate (Current Collector), 22p First Rigid Part, 22q Second Rigid Part, 22r Joint, 70 Adhesive (Adhesive Member), 111 Positive Electrode, 111S Positive Electrode Foil (Current Collector), 111p First Rigid Part, 111q Second Rigid Part, 111r Joint, 121 Positive Electrode Plate (Current Collector), S Reduction Ratio, t1, t4 First Thickness (Thickness of First Rigid Part), t2, t5 Second thickness (thickness of the second rigid part), t3 Third thickness (thickness of the current collector foil or current collector plate joined to the second rigid part).

Claims

1. A charge / discharge body including an electrode comprising a current collector and an active material, and a current collector member joined to the current collector, The current collector member comprises a first rigid portion having a predetermined rigidity and a second rigid portion adjacent to the first rigid portion and having higher rigidity than the first rigid portion. The second rigid portion provided on the current collector member and the current collector body are joined to each other. The second rigid part provided on the current collector member and the current collector body are joined by ultrasonic welding or laser welding. battery.

2. In the battery according to claim 1, The second rigid part is work hardened. battery.

3. In the battery according to claim 1, In the current collector member, the second thickness of the second rigid portion is thinner than the first thickness of the first rigid portion. The reduction ratio S of the second thickness relative to the first thickness is 0% < S ≤ 10%. battery.

4. In the battery according to claim 1, The second rigid part has a Vickers hardness that is 25% or more higher than that of the first rigid part. battery.

5. In the battery according to claim 1, The second rigid portion is formed by the plastic deformation of the current collector member. The aforementioned plastic deformation is performed by rolling a part of the current collector member. battery.

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