Battery

Abstract

To provide a battery in which assembly tolerances occurring in a battery sealing process are reduced. [Solution] A battery comprising: a battery can (100B) having a cylindrical portion (120B), a bottom wall (130B) closing one end of the cylindrical portion, and an opening edge (110B) continuing to the other end of the cylindrical portion; an electrode body (200) housed in the cylindrical portion; and a sealing body (300B) fixed to the opening edge so as to seal the opening of the opening edge, wherein the sealing body has a sealing plate (310B) and a gasket (320B) arranged on the peripheral edge of the sealing plate, and the gasket has an inner ring portion arranged on the electrode body side of the peripheral edge, an outer ring portion arranged on the opposite side of the peripheral edge from the electrode body, and a side wall portion covering the end face of the peripheral edge, and the sealing plate and the gasket are molded as a single unit and are therefore in close contact with each other.

Description

Technical Field

[0001] The present invention relates to a battery including an electrode body and a battery can for housing the electrode body.

Background Art

[0002] As a method of sealing the opening of a battery can after housing an electrode body in the battery can, as shown in Patent Document 1, after forming a groove in a battery case (battery can), a gasket and a sealing plate are inserted into the opening of the battery case, and the portion beyond the groove of the battery case is tightened inward with the outer peripheral edge portion of the sealing plate covered with the gasket. This is generally done.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Generally, the battery can functions as one external terminal, and the sealing body functions as the other external terminal. Then, the electrode at the same potential as the battery can is collected from the bottom of the battery can. On the other hand, the electrode at the same potential as the sealing body is collected from the sealing body arranged to face the bottom of the battery can. That is, when external lead wires are respectively connected to each electrode, one external lead wire is led out from the lower surface of the battery, and the other external lead wire is led out from the upper surface of the battery. Therefore, a space for wiring is required in the vertical direction of the battery.

Means for Solving the Problems

[0005] One aspect of the present invention relates to a battery including a battery can having a cylindrical portion, a bottom wall closing one end of the cylindrical portion, and an opening edge continuous with the other end of the cylindrical portion, an electrode body housed in the cylindrical portion, and being fixed to the opening edge so as to seal the opening of the opening edge. , a sealing body having a first main surface facing the inside of the battery can, a second main surface opposite to the first main surface, and a side surface connecting the first main surface and the second main surface, and covering at least a part of the opening edge and being electrically connected to the opening edge and electrically insulated from the sealing plate, and a conductive cap and relates to a battery.

Effects of the Invention

[0006] According to the present invention, The space required for the wiring of the battery can be reduced.

[0007] The novel features of the present invention are described in the appended claims. However, the present invention relates to both the configuration and the content, and will be better understood from the following detailed description in conjunction with the drawings, together with other objects and features of the present invention.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5A

Figure 5B

Figure 6A

Figure 6B

Figure 6C

Embodiments for Carrying Out the Invention

[0009] The battery according to the present embodiment includes a battery can having a cylindrical portion, a bottom wall closing one end of the cylindrical portion, and an opening edge continuous with the other end of the cylindrical portion, an electrode body housed in the cylindrical portion, and a sealing body fixed to the opening edge so as to seal the opening of the opening edge. The sealing body has a sealing plate and a gasket disposed at the peripheral portion of the sealing plate. And the sealing plate and the gasket are in close contact with each other by being integrally formed.

[0010] Hereinafter, the direction from the sealing body toward the electrode body is defined as the downward direction, and the direction from the electrode body toward the sealing body is defined as the upward direction. Generally, when the battery can is made to stand upright with the bottom facing downward, the direction parallel to the axis of the cylindrical portion toward the opening edge is the upward direction.

[0011] Conventionally, as a method of sealing the opening edge of a battery can, after providing a reduced-diameter portion having an inner diameter smaller than that of the opening edge and the cylindrical portion between the opening edge and the cylindrical portion, a sealing plate is disposed on the reduced-diameter portion via a gasket, and the opening edge of the metal can is pressed from the vertical direction to sandwich the gasket and the sealing plate and perform caulking. However, in this method, it is difficult to make the contact position in the gasket that contacts the peripheral edge portion of the sealing plate constant, and the contact position is liable to shift in the vertical direction. For this reason, depending on the position in the circumferential direction of the opening edge, variations are likely to occur in the contact position in the gasket that contacts the peripheral edge portion of the sealing plate. As a result of the variations, when the battery after sealing is viewed from above, the inner peripheral contour of the gasket (outer ring portion) that contacts the sealing plate above the peripheral edge portion is not circular, and the shape of the outer ring portion is liable to be an uneven ring shape with different widths depending on the position in the circumferential direction.

[0012] In particular, when it is desired to make the width of the outer ring portion long in order to ensure insulation, if caulking is performed such that a region above the contact position with the peripheral edge portion of the sealing plate in the gasket is made large, the shape of the outer ring portion becomes an uneven ring shape like a wavy shape, and the appearance is liable to be impaired. Also, wrinkles are liable to occur in the outer ring portion.

[0013] The gasket has a role of insulating the opening edge of the battery can and the sealing plate. However, if the width of the outer ring portion is short, it becomes difficult to ensure insulation between the opening edge of the battery can and the sealing plate. When the shape of the outer ring portion is an uneven ring shape, since the width of the outer ring portion varies depending on the position in the circumferential direction, insulation between the opening edge and the sealing plate can be ensured in the portion where the width of the outer ring portion is long, but it is also possible that insulation cannot be ensured in the portion where the width of the outer ring portion is short.

[0014] In contrast, in the present embodiment, a sealing body in which a sealing plate and a gasket are integrally formed is used. As a method of integral molding, insert molding can be used. Thereby, variations in the width of the outer ring portion are suppressed, and insulation between the opening edge of the battery can and the sealing plate can be ensured over the entire circumference of the opening edge. It is also easily possible to widen the width of the outer ring portion to increase the insulation distance between the opening edge and the sealing plate.

[0015] In a sealing body in which a sealing plate and a gasket are integrally formed, the shapes of the sealing plate and the gasket are not limited and can be designed in any shape. The gasket has an inner ring portion disposed on the electrode body side (inside) of the peripheral edge of the sealing plate, an outer ring portion disposed on the opposite side (outside) of the electrode body at the peripheral edge of the sealing plate, and a side wall portion covering the end face of the peripheral edge of the sealing plate. In the conventional sealing method, the inner ring portion is compressed upward, the outer ring portion is compressed downward, and close contact between the gasket and the sealing plate is ensured. The shapes of the inner ring portion, the outer ring portion, and the side wall portion are not limited and can be designed in any shape.

[0016] For example, the shape of the inner peripheral contour of the outer ring portion can be designed into any shape having rotational symmetry and / or plane symmetry, such as a circle, a regular polygon, or a wavy curve, and can also be designed into a shape having a fitting function with other components such as a current collecting lead. It is also easy to provide an opening or unevenness where the sealing plate is exposed at a specific position of the outer ring portion or the inner ring portion, or to thicken a predetermined position of the outer ring portion.

[0017] As a configuration of the sealing plate, in order to provide an explosion-proof function, there is a structure in which a thin portion is provided in an annular region between the peripheral portion and the central portion. In this case, when the internal pressure of the battery rises above a threshold value, the thin portion with relatively low structural strength is selectively broken, and the thin portion acts as an explosion-proof valve. On the other hand, since the structural strength of the thin portion is reduced, it is brittle against external impacts and is easily affected by external corrosion. However, by designing the shape of the outer ring portion so as to cover at least a part of the thin portion, the outer ring portion can protect the thin portion from external impacts and corrosion. The outer ring portion may cover 20% or more of the area of the thin portion, or may cover 100%.

[0018] In the conventional sealing method, as described above, since there are variations in the contact positions within the gasket that contacts the peripheral portion of the sealing plate, there may be cases where the thin portion is not covered by the outer ring portion depending on the circumferential position. On the other hand, if the width of the outer ring portion is set to be larger in consideration of the variations in the contact positions so that the thin portion is covered by the outer ring portion by a certain area or more over the entire circumference of the opening edge, there may also be cases where the outer ring portion blocks the central portion of the sealing plate depending on the circumferential position. For this reason, it has been difficult in the conventional sealing method using separate members for the sealing plate and the gasket to extend the outer ring portion in the inner direction of the cylinder so that the thin portion is covered by the outer ring portion. However, by using a sealing body in which the sealing plate and the gasket are integrally formed, the occurrence of the above problems is suppressed.

[0019] On the other hand, when the integrally formed sealing body is pressed through the opening edge of the metal can and caulked, tensile stress in the radial direction (the direction toward the axis of the cylindrical portion) is applied to the gasket during pressing. As a result, cracks may occur in the outer ring portion or the inner ring portion of the gasket, or the adhesion may peel off at the interface between the outer ring portion or the inner ring portion and the sealing plate. In particular, when cracks or peeling occur in the outer ring portion, the insulation between the opening edge and the sealing plate may become insufficient, or the protection against external impacts and corrosion may become insufficient.

[0020] In caulking, in order to suppress cracking and peeling of the outer ring portion, the outer ring portion may have a protrusion that protrudes (upward) on the side opposite to the electrode body. The protrusion is compressed downward during caulking. By compressing the protrusion, transmission of tensile stress to the inner peripheral side of the protrusion is suppressed, and generation of cracking and peeling in the outer ring portion located on the inner peripheral side of the protrusion is suppressed.

[0021] In order to enhance the adhesion between the gasket and the sealing plate, at least one of the opposing surface of the peripheral edge portion with the outer ring portion and / or the opposing surface with the inner ring portion may have a recess extending in the thickness direction of the sealing plate. The surface area of contact between the gasket and the sealing plate can be increased, thereby enhancing the adhesion. Also, peeling of the outer ring portion or the inner ring portion can be suppressed against the tensile stress applied during caulking.

[0022] Note that the sealing body of the present embodiment is not limited to a battery in which a reduced-diameter portion is provided by a conventional sealing method, and can also be preferably used even when a sealing method without a reduced-diameter portion is adopted. By integrally molding the sealing plate and the gasket, the sealing body can be handled as a single part, facilitating the manufacture of the battery.

[0023] Examples of the sealing method without a reduced-diameter portion include a method of laterally pressing the side wall portion of the gasket in the radial direction of the opening (the direction toward the axis of the cylindrical portion) through the opening edge of the battery can. Specifically, by providing a pressing portion on the opening edge to press the gasket against the end face of the peripheral edge portion of the sealing plate, the gasket is compressed in the radial direction of the opening between the end face of the peripheral edge portion of the sealing plate and the opening edge by the pressing, and the sealing property between the sealing body and the opening edge can be ensured by the repulsive force of the gasket.

[0024] Hereinafter, the battery according to the embodiment of the present invention will be specifically described with reference to the drawings, but the present invention is not limited thereto.

[0025] [First Embodiment]

[0026] FIG. 1 is a schematic longitudinal sectional view of a main part of the battery 10A according to the present embodiment, and FIG. 2 is a perspective view of the same battery. The battery 10A has a cylindrical shape and includes a cylindrical bottomed battery can 100A, a cylindrical electrode body 200 housed in the can, and a sealing body 300A that seals the opening of the battery can 100A.

[0027] The battery can 100A has a cylindrical portion 120A that houses the electrode body 200, a bottom wall 130A that closes one end of the cylindrical portion 120A, and an opening edge 110A that is continuous with the other end of the cylindrical portion 120A. The opening of the opening edge 110A is closed by the sealing body 300A.

[0028] The sealing body 300A has a sealing plate 310A and a gasket 320A disposed on the peripheral portion 311A of the sealing plate 310A. The sealing plate 310A is in a disk shape or a disc shape and has an explosion-proof function. Specifically, the sealing plate 310A includes a thick peripheral portion 311A and a central region 312A for ensuring structural strength, and a thin portion 313A that exhibits an explosion-proof function. The thin portion 313A is provided in a region between the peripheral portion 311A and the central region 312A. An end portion of a lead wire 210 led out from a positive electrode or a negative electrode constituting the electrode body 200 is connected to the inner surface of the central region 312A. Therefore, the sealing plate 310A has one terminal function.

[0029] When the internal pressure of the battery can 100A rises, the sealing plate 310A bulges outward. For example, stress due to tension concentrates at the boundary between the peripheral portion 311A and the thin portion 313A, and breakage occurs from that boundary portion. As a result, the internal pressure of the battery can 100A is released, and the safety of the battery 10A is ensured.

[0030] The gasket 320A has an outer ring portion 321A, an inner ring portion 322A, and a side wall portion 323A that connects the outer ring portion 321A and the inner ring portion 322A. The end face 311T of the peripheral portion 311A of the sealing plate 310A is covered by the side wall portion 323A.

[0031] The outer ring portion 321A, the inner ring portion 322A, and the side wall portion 323A are an integrated molded body. The gasket 320A can be integrally molded with the sealing plate 310A by, for example, insert molding.

[0032] The outer ring portion 321A extends radially inward from the inner ring portion 322A. The outer ring portion 321A covers at least a part of the thin portion 313A of the sealing plate 310A. Thereby, the outer ring portion 321A protects the thin portion 313A from external impact and corrosion, and can increase the insulation distance between the opening edge 110A and the sealing plate 310A.

[0033] Between the cylindrical portion 120A and the opening edge 110A of the battery can 100A, a reduced diameter portion 140 having an inner diameter smaller than the inner diameter of the cylindrical portion of the opening edge 110A and the inner diameter of the cylindrical portion 120A is provided. That is, the opening edge 110A is continuous with the cylindrical portion 120A via the reduced diameter portion 140. The reduced diameter portion 140 includes a first reduced diameter portion 141a whose inner diameter continuously decreases from the cylindrical portion 120A, and a second reduced diameter portion 141b whose inner diameter continuously decreases from the opening edge 110A and is continuous with the first reduced diameter portion 141a at a position where the inner diameter becomes extremely small. The inner ring portion 322A of the gasket is in contact with the second reduced diameter portion 141b.

[0034] One end of the opening edge 110A is continuous with the second reduced diameter portion 141b. The other end 110E of the opening edge 110A constitutes an open end and is bent inward to contact the outer ring portion 321A.

[0035] The inner ring portion 322A is compressed upward via the second reduced diameter portion 141b, and the outer ring portion 321A is compressed downward via the other end 110E of the opening edge 110A, so that the gap between the sealing body and the opening edge is sealed by the repulsive force of the gasket.

[0036] FIG. 3 is a schematic cross-sectional view showing an example of the configuration of the sealing body 300A as a component before sealing the battery can 100A with the sealing body 300A to form the battery 10A. As described above, the sealing body 300A has the sealing plate 310A and the gasket 320A. A protrusion 324 protruding upward is provided on the outer ring portion 321A of the gasket 320A.

[0037] Since the protrusion 324 is compressed downward in the caulking process when sealing the battery can, its presence is not shown in FIG. 1. However, in the caulking process, when the protrusion 324 is compressed, the transmission of tensile stress to the outer ring portion 321A on the inner peripheral side of the protrusion 324 is suppressed. As a result, the occurrence of cracks and peeling of the outer ring portion can be suppressed.

[0038] In addition, the sealing plate 310A is provided with recesses 314 on the opposing surfaces with the outer ring portion 321A of the peripheral edge portion 311A and the inner ring portion 322A.

[0039] The recess 314 has the effect of increasing the contact area between the gasket 320A and the sealing plate 310A and enhancing the adhesion between the gasket 320A and the sealing plate 310A, for example, when the gasket 320A is integrally formed on the sealing plate 310A to form the sealing body. Further, peeling of the outer ring portion or the inner ring portion can be suppressed against the tensile stress applied during the caulking process.

[0040] The direction of the recess of the recess 314 may be inclined from the thickness direction of the sealing plate (see FIG. 3). Thereby, the recess 314 forms a hook, enhances the adhesion between the gasket 320A and the sealing plate 310A, and suppresses the gasket 320A from peeling off from the sealing plate 310A due to impacts during transportation or assembly.

[0041] The width W1 of the inner ring portion and the width W2 of the outer ring portion are both constant over the entire circumference of the sealing body, and W2 > W1 may be possible.

[0042] [Second Embodiment]

[0043] It may further include a conductive cap that covers at least a part of the opening edge, is electrically connected to the opening edge, and is electrically insulated from the sealing plate. Thereby, the space required for the wiring of the battery can be reduced.

[0044] In a battery with a conventional configuration, usually, the battery can functions as one external terminal, and the sealing body functions as the other external terminal. And the electrode at the same potential as the battery can is collected from the bottom of the battery can. On the other hand, the electrode at the same potential as the sealing body is collected from the sealing body arranged to face the bottom of the battery can. That is, when external lead wires are respectively connected to each electrode, one external lead wire is led out from the lower surface of the battery, and the other external lead wire is led out from the upper surface of the battery. Therefore, a space for wiring is required in the vertical direction of the battery.

[0045] In the battery of this embodiment, the sealing body functions as an external terminal of one electrode (for example, the positive electrode) of the battery. The sealing body has a first main surface facing the inside of the battery can, a second main surface opposite to the first main surface, and a side surface connecting the first main surface and the second main surface. On the other hand, the cap connected to the battery can is arranged on the opening edge side and functions as an external terminal of the other electrode (for example, the negative electrode) of the battery. Therefore, both electrodes can be collected from the vicinity of the sealing body (for example, the second main surface side). Thus, the space (wiring space) for wiring the leads connected to each external terminal only needs to exist on the sealing body side, and the wiring space is reduced in size. Furthermore, the cap is an accessory of the battery that is separate from the battery can. Therefore, the cap can be formed into a shape according to the use and shape of the battery. Thus, this embodiment can be applied regardless of the shape of the battery (battery can).

[0046] The cap may have a first portion that covers at least a part of the side surface of the sealing body via the opening edge of the battery can. Thereby, the contact area with the battery can is increased and the current collection performance is improved. Further, the cap may have a second portion that covers at least a part of the outer peripheral edge of the second main surface of the sealing body. Thereby, it becomes easier to collect current from both electrodes from the second main surface side of the sealing body. An opening edge of the battery can may be interposed between the second portion and the second main surface of the sealing body.

[0047] The cap may have both the first portion and the second portion. That is, a cross-section of the cap along the axial direction (hereinafter also referred to as the Z direction) of the battery can may be substantially L-shaped. Thereby, the cap is firmly fixed to the battery can, and the contact area with the battery can is increased, improving the current collection performance. Further, the edge on the second main surface side of the battery is protected by the cap.

[0048] When the cap includes an annular first portion, in a no-load state, the minimum inner diameter of the first portion may be made smaller than the maximum outer diameter of the portion of the opening edge covered by the cap. By press-fitting and fitting a battery into such a cap, the cap is firmly fixed by the battery.

[0049] The cap may be welded to the opening edge of the battery can. Thereby, the cap is firmly fixed by the battery, and the resistance is reduced, improving the current collection performance. The welding method is not particularly limited and may be appropriately selected according to the materials of the cap and the opening edge. Examples of the welding method include laser welding and resistance welding. As a method other than welding, for example, the inside of the cap may be threaded, and the connecting portion of the battery can may be threaded to correspond to the threads of the cap. By fitting both threads together, the cap can be fixed to the battery can. The threading may be performed on only one of the cap and the battery can. Also in this case, the cap is fixed to the battery can.

[0050] When the end face of the opening edge is disposed on the side surface of the sealing body, that is, when the opening edge of the battery can does not cover the second main surface of the sealing body, the cap is particularly useful. Usually, in this case, it is not possible to collect current from both electrodes from the second main surface side of the sealing body. However, by using a cap that is electrically connected to the battery can, it is possible to collect current from both electrodes from the second main surface side of the sealing body regardless of the form of the opening edge of the battery can.

[0051] When the end face of the opening edge is disposed on the side surface of the sealing body, in the height direction of the battery can, the outer diameter of the opening edge at the lowest position in contact with the sealing body is preferably smaller than the outer diameter of the cylindrical portion. Thereby, the thickness of the cap can be designed such that the outer diameter of the cap and the outer diameter of the cylindrical portion are substantially the same. That is, even when the cap is fitted to the battery can, the change in the axial direction of the diameter of the battery can be reduced.

[0052] Hereinafter, a battery according to an embodiment of the present invention that includes a cap will be specifically described with reference to the drawings. However, the present invention is not limited thereto.

[0053] FIG. 4 is a schematic longitudinal sectional view of a battery 10B according to the present embodiment. FIG. 5A is a perspective view schematically showing the cap according to the present embodiment. FIG. 5B is a perspective view of the cap as seen from the side opposite to FIG. 5A.

[0054] The battery 10B is cylindrical and includes a cylindrical bottomed battery can 100B, a cylindrical electrode body 200 housed in the battery can 100B, a sealing body 300B that seals the opening of the battery can 100B, and a conductive and annular cap 400 that is electrically connected to the battery can 100B and is electrically insulated from the sealing body 300B.

[0055] The battery can 100B has a cylindrical portion 120B that houses the electrode body 200, a bottom wall 130B that closes one end of the cylindrical portion 120B, and an opening edge 110B that is continuous with the other end of the cylindrical portion 120B. The opening of the opening edge 110B is closed by the sealing body 300B.

[0056] The sealing body 300B includes a first main surface 300X facing the inside of the battery can 100B, a second main surface 300Y opposite to the first main surface 300X, and a side surface 300Z connecting the first main surface 300X and the second main surface 300Y. The end surface 110T of the opening edge 110B is on the second main surface 300Y of the sealing body 300B, and a part of the opening edge 110B covers the outer peripheral edge of the second main surface 300Y.

[0057] The sealing body 300B also has a sealing plate 310B and a gasket 320B disposed at the peripheral portion 311B of the sealing plate 310B. The sealing plate 310B is disk-shaped or disc-shaped and has an explosion-proof function. Specifically, the sealing plate 310B includes a thick peripheral portion 311B and a central region 312B for ensuring structural strength, and a thin portion 313B for exerting the explosion-proof function. The thin portion 313B is provided in an annular region between the peripheral portion 311B and the central region 312B. An end portion of the internal lead wire 210 led out from the positive electrode or the negative electrode constituting the electrode body 200 is connected to the inner surface of the central region 312B. Therefore, the sealing plate 310B has one terminal function. However, the shape of the sealing body 300B is not limited to this.

[0058] When the internal pressure of the battery can 100B rises, the sealing plate 310B bulges outward. For example, stress due to tension concentrates at the boundary between the peripheral portion 311B and the thin portion 313B, and breakage occurs from that boundary portion. As a result, the internal pressure of the battery can 100B is released, and the safety of the battery 10B is ensured.

[0059] The cap 400 has a first portion 401 covering the side surface 300Z of the sealing body 300B and a second portion 402 covering the outer peripheral edge of the second main surface 300Y of the sealing body 300B via the opening edge 110B of the battery can 100B.

[0060] In terms of not interfering with the explosion-proof function, it is preferable that the second portion 402 of the cap 400 does not cover the thin portion 313B, and it is more preferable that the second portion 402 does not cover the boundary between the peripheral portion 311B and the thin portion 313B. The second portion 402 covers, for example, only a part of the peripheral portion 311B.

[0061] The cap 400 is conductive and has the same polarity as the battery can 100B. Therefore, the cap 400 can be provided with the other terminal function having a polarity different from that of the sealing body 300B (sealing plate 310B). Thus, both electrodes of the battery 10B can be collected from the second main surface 300Y side of the sealing body 300B. That is, regardless of the form of the opening edge 110B of the battery can 100B, each external lead wire can be led out from the second main surface 300Y side. The cap 400 and the sealing plate 310B are insulated by, for example, a gasket 320B. In FIG. 5, a state is illustrated in which the first external lead wire 501 is connected to the second portion 402 of the cap 400 and the second external lead wire 502 is connected to the outer surface of the central region 312B of the sealing plate 310B.

[0062] In the no-load state, the minimum inner diameter D of the first portion 401 of the cap 400 401 (see FIG. 2B) is smaller than the maximum outer diameter D of the portion covered by the first portion 401 of the opening edge 110B. 110 The battery 10B is press-fitted into the cap 400, and the cap 400 is fixed to the battery 10B. From the viewpoint of fixability, the inner diameter D 401 / outer diameter D 110 may be 0.99 or less, or may be 0.98 or less. On the other hand, in terms of easy press-fitting, the inner diameter D 401 / outer diameter D110 is preferably 0.9 or more.

[0063] One or more cuts 403 may be provided in the first portion 401 of the cap 400.

[0064] The cap 400 is welded to the opening edge 110B. Preferably, the first portion 401 is welded to the opening edge 110B.

[0065] [Third Embodiment]

[0066] FIG. 6A is a schematic longitudinal sectional view of the battery 10C according to the present embodiment including the cap 400. FIG. 6B is an enlarged schematic longitudinal sectional view of the main part of the battery shown in FIG. 6A. FIG. 6C is a perspective view of the battery shown in FIG. 6A.

[0067] The end face 110T of the opening edge 110C of the battery can 100C is on the side face 300Z of the sealing body 300C, and the opening edge 110C does not cover the outer peripheral edge of the second main face 300Y of the sealing body 300C.

[0068] By using the cap 400, even when the opening edge 110C does not cover the second main face 300Y, both electrodes can be collected from the vicinity of the sealing body 300C, and further from the second main face 300Y side. A conductive bonding material 410 may be interposed between the first portion 401 of the cap 400 and the outer surface of the opening edge 110C.

[0069] In the height direction of the battery can 100C, the outer diameter of the opening edge 110C of the battery can 100C at the lowest position in contact with the sealing body 300C may be smaller than the outer diameter of the cylindrical portion 120C. For example, the opening edge 110C may include a tapered region 110S (see FIG. 6B) that reduces the outer diameter of the cylindrical portion 120C at the boundary with the cylindrical portion 120C. The tapered region 110S forms an angle of less than 45° with the Z direction, for example.

[0070] In this case, the thickness of the cap 400 can be designed such that the outer diameter of the cap 400 and the outer diameter of the cylindrical portion 120C are substantially the same. Thereby, the change in the diameter of the battery 10C in the Z direction can be reduced. The difference between the outer diameter or the maximum outer diameter of the cap 400 and the outer diameter or the maximum outer diameter of the cylindrical portion 120C may be, for example, 20% or less of the outer diameter of the cylindrical portion 120C, 10% or less, 5% or less, 2% or less, or 1% or less.

[0071] When the first portion 401 of the cap 400 covers at least a part of the tapered region 110S, the cap 400 and the opening edge 110C may be welded in the tapered region 110S. Positioning becomes easy, and deterioration of the gasket 320C due to heat can be suppressed.

[0072] In this embodiment, at least a part of the opening edge 110C preferably presses the side wall portion 323C of the gasket 320C against the end surface 311T of the peripheral edge portion 311C of the sealing plate 310C, and compresses the side wall portion 323C in the radial direction of the opening. Thereby, it becomes easier to ensure the sealing performance between the opening edge 110C of the battery can 100C and the sealing body 300C. For example, the opening edge 110C presses the gasket 320C in a direction perpendicular to the Z direction (hereinafter also referred to as the XY direction), rather than in the Z direction. In this case, when the force with which the opening edge 110C presses the gasket 320C is decomposed into the Z direction and the XY direction, the vector in the XY direction has a scalar amount larger than the vector in the Z direction.

[0073] Hereinafter, the sealing plate 310C, the gasket 320C, and the opening edge 110C suitable for the case where the opening edge 110C presses the gasket 320C in the XY direction will be described. Other configurations may be the same as those in the second embodiment.

[0074] The gasket 320C has an outer ring portion 321C, an inner ring portion 322C, and a side wall portion 323C connecting the outer ring portion 321C and the inner ring portion 322C. The end surface 311T of the peripheral edge portion 311C of the sealing plate 310C is covered by the side wall portion 323C. The gasket 320C is fixed to the sealing plate 310C by sandwiching the peripheral edge portion 311C of the sealing plate 310C between the outer ring portion 321C and the inner ring portion 322C.

[0075] In the height direction of the battery can 100C of the battery 10C, the outer diameter of the opening edge 110C of the battery can 100C at the lowest position in contact with the inner ring portion 322C of the gasket 320C is smaller than the outer diameter of the cylindrical portion 120C. Also, the outer ring portion 321C protrudes in the axial direction (Z direction) of the battery can 100C from the end face 110T of the opening edge 110C. Also in this case, the cap 400 is useful. Usually, in this case, the gasket 320C becomes an obstacle, and it is difficult to collect current from both electrodes from the second main surface 300Y side of the sealing body 300C. However, by using the cap 400, it becomes possible to easily collect current from both electrodes from the second main surface 300Y side.

[0076] The outer ring portion 321C, the inner ring portion 322C, and the side wall portion 323C are an integrated molded body. The gasket 320C can be integrally molded with the sealing plate 310C, for example, by insert molding. According to integral molding, a state in which the sealing plate 310C and the gasket 320C are in close contact with each other can be easily achieved. By integrally molding the sealing plate 310C and the gasket 320C, the sealing body 300C can be handled as one component, and the manufacture of the battery 10C becomes easy.

[0077] In FIG. 6A, inside the opening edge 110C, a reduced-diameter protrusion 111 is formed along the circumferential direction of the opening. This protrusion 111 presses the side wall portion 323C against the end face 311T. A recess 3231 may be provided in advance at a position corresponding to the protrusion 111 on the side wall portion 323C of the gasket 320C. By providing the recess 3231 in the gasket 320C, excessive deformation of the gasket 320C when the side wall portion 323C is compressed can be suppressed.

[0078] The protruding portions 111 may be formed in a plurality of intermittent manners along the circumferential direction of the opening, or may be formed continuously along the circumferential direction of the opening. The continuously formed protruding portions 111 may form an annular groove portion along the circumferential direction of the opening. The protruding portions 111 can press the gasket 320C or its side wall portion 323C more strongly toward the end face 311T of the peripheral edge portion 311C of the sealing plate 310C. Therefore, the sealing performance between the sealing body 300C and the opening edge 110C is more reliably ensured. When forming a plurality of protruding portions 111 intermittently, it is preferable to provide a plurality of (at least two locations, preferably four or more) protruding portions 111 at positions that are angularly equivalent with respect to the center of the opening.

[0079] In the height direction of the battery can 100C, the position of the protruding portion 111 and the center position of the end face 311T are substantially the same. Thereby, the deformation of the sealing plate 310C and the gasket 320C is suppressed. Also, the pressure applied to the gasket 320C or its side wall portion is less likely to be uneven. Therefore, the deformation of the gasket 320C is easily suppressed, and the compression ratio of the gasket 320C can be increased, and the sealing performance between the sealing body 300C and the opening edge 110C can be more significantly ensured.

[0080] Here, the fact that the position of the protruding portion 111 and the center position of the end face 311T of the sealing plate 310C are substantially the same means that, in the height direction of the battery can 100C, the deviation amount between the position of the protruding portion 111 and the center position of the end face 311T of the sealing plate 310C is 4% or less of the height H of the battery can 100C.

[0081] A concave groove 3111 is formed at the center position of the end face 311T of the peripheral edge portion 311C so as to correspond to the protruding portion 111 of the opening edge 110C. In the height direction of the battery can 100C, the deviation amount between the center position of the concave groove 3111 and the position of the protruding portion 111 may be 4% or less of the height H of the battery can 100C.

[0082] According to the above configuration, it is not necessary to press the gasket in the Z direction to seal the inside of the battery can. Therefore, the battery can 100C does not necessarily have a reduced-diameter portion intervening between the gasket and the electrode body as shown in FIGS. 1 and 4. In this case, the shortest distance between the sealing body 300C and the electrode body 200 can be, for example, 2 mm or less, preferably 1.5 mm or less, and more preferably 1 mm or less.

[0083] The materials of the battery cans 100A, 100B, and 100C are not particularly limited, and examples thereof include iron and / or iron alloys (including stainless steel), copper, aluminum, aluminum alloys (alloys containing trace amounts of other metals such as manganese and copper), and the like. The material of the cap 400 is also not particularly limited, and the same materials as those of the battery cans 100A and 100B can be exemplified.

[0084] The materials of the gaskets 320A, 320B, and 320C are not limited, but for example, as materials that are easy to integrally mold, polypropylene (PP), polyphenylene sulfide (PPS), polyethylene (PE), polybutylene terephthalate (PBT), perfluoroalkoxy alkane (PFA), polytetrafluoroethylene (PTFE), polyamide (PA), etc. can be used.

[0085] Next, taking a lithium-ion secondary battery as an example, the configuration of the electrode body 200 will be exemplarily described.

[0086] The cylindrical electrode body 200 is of a wound type, and the positive electrode and the negative electrode are wound in a spiral shape with a separator interposed therebetween. A lead wire 210 is connected to one of the positive electrode and the negative electrode. The lead wire 210 is connected to the inner surface of the central region of the sealing plate by welding or the like. Another lead wire is connected to the other of the positive electrode and the negative electrode, and the other lead wire is connected to the inner surface of the battery can by welding or the like.

[0087] (Negative electrode)

[0088] The negative electrode has a strip-shaped negative electrode current collector and negative electrode active material layers formed on both sides of the negative electrode current collector. As the negative electrode current collector, a metal film, a metal foil, etc. are used. The material of the negative electrode current collector is preferably at least one selected from the group consisting of copper, nickel, titanium, alloys thereof, and stainless steel. The thickness of the negative electrode current collector is preferably, for example, 5 to 30 μm.

[0089] The negative electrode active material layer contains a negative electrode active material and, if necessary, a binder and a conductive agent. The negative electrode active material layer may be a deposited film formed by a vapor phase method (e.g., vapor deposition). Examples of the negative electrode active material include Li metal, a metal or alloy that reacts electrochemically with Li, a carbon material (e.g., graphite), a silicon alloy, a silicon oxide, a metal oxide (e.g., lithium titanate), etc. The thickness of the negative electrode active material layer is preferably, for example, 1 to 300 μm.

[0090] (Positive electrode)

[0091] The positive electrode has a strip-shaped positive electrode current collector and positive electrode active material layers formed on both sides of the positive electrode current collector. As the positive electrode current collector, a metal film, a metal foil (stainless steel foil, aluminum foil or aluminum alloy foil), etc. are used.

[0092] The positive electrode active material layer contains a positive electrode active material and a binder, and if necessary, a conductive agent. The positive electrode active material is not particularly limited, but a lithium-containing composite oxide such as LiCoO2 or LiNiO2 can be used. The thickness of the positive electrode active material layer is preferably, for example, 1 to 300 μm.

[0093] As the conductive agent to be included in each active material layer, graphite, carbon black, etc. are used. The amount of the conductive agent is, for example, 0 to 20 parts by mass per 100 parts by mass of the active material. As the binder to be included in the active material layer, a fluororesin, an acrylic resin, rubber particles, etc. are used. The amount of the binder is, for example, 0.5 to 15 parts by mass per 100 parts by mass of the active material.

[0094] (Separator)

[0095] As the separator, a microporous membrane or nonwoven fabric made of resin is preferably used. As the material (resin) of the separator, polyolefin, polyamide, polyamideimide, etc. are preferable. The thickness of the separator is, for example, 8 to 30 μm.

[0096] (Electrolyte)

[0097] As the electrolyte, a non-aqueous solvent in which a lithium salt is dissolved can be used. Examples of the lithium salt include LiClO4, LiBF4, LiPF6, LiCF3SO3, LiCF3CO2, imide salts, etc. Examples of the non-aqueous solvent include cyclic carbonates such as propylene carbonate, ethylene carbonate, and butylene carbonate, chain carbonates such as diethyl carbonate, ethyl methyl carbonate, and dimethyl carbonate, and cyclic carboxylic acid esters such as γ-butyrolactone and γ-valerolactone.

[0098] In the above, a lithium-ion secondary battery was described as an example, but the present invention can be used in a battery that seals the battery can using a sealing body, regardless of whether it is a primary battery or a secondary battery.

Industrial Applicability

[0099] The battery according to the present invention can be used in various can-type batteries, and is suitable for use as a power source for, for example, portable devices, hybrid vehicles, electric vehicles, etc.

[0100] The present invention has been described with respect to a preferred embodiment at the present time, but such disclosure should not be construed in a limiting sense. Various modifications and alterations will undoubtedly become apparent to those skilled in the art in the technical field to which the present invention pertains upon reading the above disclosure. Therefore, the appended claims should be construed to include all modifications and alterations without departing from the true spirit and scope of the present invention.

Explanation of Reference Numerals

[0101] 10A, 10B, 10C: Batteries 100A, 100B, 100C: Battery cans 110A, 110B, 110C: Opening edges 110E: End portions 110S: Tapered regions 110T: End faces 111: Protrusions 120A, 120B, 120C: Cylindrical portions 130A, 130B, 130C: Bottom walls 140: Reduced-diameter portion 141a: First reduced-diameter portion 141b: Second reduced-diameter portion 200: Electrode body 210: Lead wires 300A, 300B, 300C: Sealing bodies 300X: First main surface 300Y: Second main surface 300Z: Side surfaces 310A, 310B, 310C: Sealing plates 311T: End faces 3111: Grooves 311A, 311B, 311C: Peripheral edge portions 312A, 312B, 312C: Central regions 313A, 313B, 313C: Thin-wall portions 314: Recesses 320A, 320B, 320C: Gaskets 321A, 321B, 321C: Outer ring portions 322A, 322B, 322C: Inner ring portions 323A, 323B, 323C: Side wall portions 3231: Recesses 324: Protrusions 400: Caps 401: First part 402: Second part 403: Cuts 410: Bonding materials 501: First external lead wire 502: Second external lead wire

Claims

1. A battery can having a cylindrical portion and an opening edge continuous with one end of the cylindrical portion, an electrode body accommodated in the cylindrical portion, and a sealing body fixed to the opening edge so as to seal the opening of the opening edge, having a first main surface facing the inside of the battery can, a second main surface opposite to the first main surface, and a side surface connecting the first main surface and the second main surface. The sealing body includes a sealing plate and a gasket disposed between the sealing plate and the opening edge to electrically insulate the sealing plate and the battery can. The battery further includes a conductive cap that covers at least a part of the opening edge, is electrically connected to the opening edge, and is electrically insulated from the sealing plate. The cap includes a first portion covering the side surface and a second portion covering the second main surface. The tip of the opening edge is bent inward in the radial direction of the battery can to sandwich the gasket together with the sealing plate. The second portion projects inward in the radial direction of the battery can from the tip of the opening edge. The cap is welded to the opening edge, battery.

2. The first portion of the cap is annular, The battery according to claim 1, wherein in a no-load state, the minimum inner diameter of the first portion of the cap is smaller than the maximum outer diameter of the portion of the opening edge of the battery can covered by the cap.

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