JP7346988B2 - battery - Google Patents

Description

The present invention relates to batteries, particularly secondary batteries.

BACKGROUND ART Conventionally, batteries such as primary batteries and secondary batteries have been used as power sources for various electronic devices. In particular, secondary batteries generally have a structure in which an electrode assembly (electrode body) and an electrolyte are housed within an exterior body (case), and an electrode terminal structure for achieving electrical connection of the secondary battery. Equipped with:

For example, as shown in FIGS. 5A to 5C, the battery electrode terminal structure includes a battery case 510 having a terminal extraction hole 511; a pedestal part 521 and a rivet part 522 protruding from the pedestal part; An electrode terminal 520 in which a portion 522 is provided so as to pass through the terminal extraction hole of the case from the outside of the case; a cylindrical portion 531 attached to the outer periphery of the rivet portion; an outer seal member 530 provided on the outside of the case; a connection plate 540 that electrically connects the electrode inside the case to the electrode terminal; The sealing member is provided between the case 510 and the connecting plate 540 to seal the gap between the case 510 and the connecting plate 540, and is configured to cover the outer periphery of the cylindrical portion 531 of the outer seal member 530. It includes an inner seal member 550 disposed inside. The rivet portion 522 becomes a caulked portion 5220 by caulking the tip. In such an electrode terminal structure, sealing performance inside the case 510 is required. FIG. 5A is a schematic enlarged cross-sectional view of the electrode terminal structure portion of a battery before the rivet portion of the electrode terminal is caulked in the prior art. FIG. 5B is a schematic enlarged sectional view of the electrode terminal structure portion of the battery after the rivet portion of the electrode terminal is caulked in the prior art. FIG. 5C is an exploded view of the electrode terminal structure of FIG. 5A.

On the other hand, as another example of an electrode terminal structure for a battery, an electrode terminal structure as shown in FIGS. 6A and 6B is disclosed (for example, Patent Document 1). The electrode terminal structure shown in FIGS. 6A and 6B has a battery case 610 having a terminal extraction hole; a pedestal part 621 and a rivet part 622 protruding from the pedestal part, and the rivet part 622 is inserted into the case from inside the case. An electrode terminal 620 provided to penetrate the terminal extraction hole; has a cylindrical portion 631 attached to the outer periphery of the rivet portion and a flat plate portion 632 extending in a flat plate shape from one end of the cylindrical portion in the outer radial direction; The flat plate portion includes an inner seal member 630 provided inside the case; an external terminal 640 that electrically connects the electrode terminal to the outside; and a flat plate portion provided between the case 610 and the external terminal 640; an outer seal member 650 that is a seal member that seals a gap between the case 610 and the connection plate 640 and is disposed on the outside of the case 610 so as to cover the outer periphery of the rivet portion 622 of the electrode terminal 620; We are prepared. A protrusion 635 is formed at a portion of the case 610 that is in contact with the inner seal member 630. The protrusion 635 is embedded in the seal member 630. In such an electrode terminal structure, when the electrode terminal (rivet) 620 is compressed in the axial direction X' by caulking, the protrusion 635 highly compresses the flat plate part 632 of the inner seal member 630, and the flat plate part 632 of the inner seal member 630 is compressed in the width direction Y'. Sealing performance is ensured. The rivet portion 622 becomes a caulked portion 6220 by caulking the tip. FIG. 6A is a schematic enlarged cross-sectional view of the electrode terminal structure portion of the battery after the rivet portion of the electrode terminal is caulked in another example of the prior art. FIG. 6B is a schematic enlarged cross-sectional view of a circular region B' portion in the electrode terminal structure of FIG. 6A.

Japanese Patent Application Publication No. 2016-105374

The inventors of the present invention have discovered that the following new problem occurs in the conventional electrode terminal structures shown in FIGS. 5A to 5C.

Specifically, for example, in the electrode terminal structures shown in FIGS. 5A to 5C, when the cross-sectional width dimension S2' of the pedestal portion 521 of the electrode terminal 520 was reduced in order to reduce the size, the sealing performance decreased. More specifically, in a battery, the seal between the electrode terminal 520 and the battery case 510 is a seal in the axial direction X' to prevent the electrode terminal 520 (particularly the rivet portion 522) from entering in the axial direction X' and leaking. Sealing performance in the width direction Y' is required to prevent entry and leakage in the direction Y' (hereinafter simply referred to as "width direction Y'") perpendicular to the axial direction X'. When the cross-sectional width dimension S2' of the pedestal portion 521 of the electrode terminal 520 is reduced for miniaturization, the sealing length in the width direction Y' is shortened, so that the sealing performance in the width direction Y' is reduced. When the cross-sectional width dimension S2' of the pedestal portion 521 of the electrode terminal 520 is reduced for miniaturization, the compressive force in the axial direction X' is relatively reduced compared to the width direction Y'. Therefore, when reducing the cross-sectional width dimension S2' of the pedestal portion 521, the sealing performance in the axial direction X' based on the compressive force in the width direction Y' is better than the width dimension S2' based on the compressive force in the axial direction X'. This is considered to be more important than the sealing performance in the direction Y'.

In the electrode terminal structures shown in FIGS. 5A to 5C, in which the cross-sectional width dimension S2' of the pedestal portion 521 of the electrode terminal 520 is reduced for miniaturization, if the case is made thinner for further miniaturization, the sealing performance will be improved. decreased further. Specifically, when the case is made thinner, the sealing member 530 is damaged by the end 512 (particularly the end face thereof) of the electrode extraction hole 511 (see FIG. 5C) in the case 510, as shown in FIGS. 5D to 5E, and the seal member 530 is damaged in the axial direction ' The sealing performance of ' has decreased. Therefore, reducing the compressive force in the width direction Y' may be considered to avoid this damage, but when the compressive force in the width direction Y' is reduced, the sealing performance in the axial direction X' also deteriorates. FIG. 5D is a schematic enlarged sectional view of a circular region A' portion in the electrode terminal structure of FIG. 5B when the case is made thinner. FIG. 5E is a schematic cross-sectional view showing simulation results regarding the magnitude of stress under conditions when the rivet height is compressed from 2.15 mm to 1.45 mm. FIG. 5F is a partially enlarged sectional view of the circular area in FIG. 5E. It is clear from FIGS. 5E and 5F that stress is concentrated on the sealing member due to the edges of the case (particularly the end faces thereof). In FIGS. 5E and 5F, stress increases in the order of blue, green, and yellow. In addition, the simulation results (drawings) (actual product: color copy) of FIGS. 5E and 5F will be submitted as reference materials in the property submission form.

Furthermore, in the electrode terminal structures of FIGS. 5A to 5C, if the case is made thinner for further miniaturization, when the case is deformed due to external loads or changes over time, the case and sealing member (especially its cylindrical portion) In some cases, it became impossible to maintain contact (or a contact portion) with the material, the compressive force in the width direction Y' decreased, and the sealing performance in the axial direction X' decreased.

The present invention improves the sealing performance of the electrode terminal (particularly the rivet part) even if the cross-sectional width dimension of the pedestal part of the electrode terminal is made relatively small and the case is made relatively thin in order to miniaturize the battery. An object of the present invention is to provide a battery that has sufficiently excellent sealing performance in the axial direction X.

The present invention
an electrode assembly including an electrode;
a case that houses the electrode assembly and has a terminal extraction hole;
an electrode terminal having a pedestal part and a rivet part protruding from the pedestal part, the rivet part being provided so as to pass through a terminal extraction hole of the case;
A sealing member is provided between the case and the electrode terminal, and seals a gap between the case and the electrode terminal, and includes a cylindrical portion attached to the outer periphery of the rivet portion, and a sealing member provided from one end of the cylindrical portion to the outside. a sealing member having a flat plate portion extending in the radial direction in a flat plate shape, the flat plate portion being provided on the side where the pedestal portion of the electrode terminal is disposed on the outside or inside of the case;
a connection plate that electrically connects the electrode inside the case to the electrode terminal, the connection plate being attached to the outer periphery of the rivet portion;
Equipped with
The case relates to a battery, in which the terminal draw-out hole is provided with a raised edge portion on the edge of the terminal hole.

In the battery of the present invention, even if the cross-sectional width dimension of the base part of the electrode terminal is made relatively small in order to miniaturize the battery, and the case is made relatively thin, the seal of the electrode terminal (particularly the rivet part) properties (particularly sealing properties in the axial direction X).

1 is a schematic perspective view showing the appearance of a battery (for example, a secondary battery) according to an embodiment of the present invention. FIG. 2 is a schematic enlarged cross-sectional view of an electrode terminal structure portion of a battery (for example, a secondary battery) according to an embodiment of the present invention before the rivet portion of the electrode terminal is caulked. FIG. 1B is a schematic enlarged cross-sectional view of the electrode terminal structure portion of the battery (for example, a secondary battery) of the present invention shown in FIG. 1B after the rivet portion of the electrode terminal is caulked. FIG. 2B is a schematic enlarged cross-sectional view of a circular region A portion of the electrode terminal structure of FIG. 2A. FIG. 1B is an exploded view of the electrode terminal structure of FIG. 1B. FIG. 7 is a schematic enlarged sectional view of an electrode terminal structure portion of a battery (for example, a secondary battery) according to another embodiment of the present invention after the rivet portion of the electrode terminal is caulked. 4A is a schematic enlarged cross-sectional view of a circular region B portion of the electrode terminal structure of FIG. 4A. FIG. FIG. 2 is a schematic enlarged cross-sectional view of the electrode terminal structure portion of a conventional battery before the rivet portion of the electrode terminal is caulked. 5A is a schematic enlarged cross-sectional view of the electrode terminal structure portion of the battery of the prior art shown in FIG. 5A after the rivet portion of the electrode terminal is caulked. FIG. FIG. 5B is an exploded view of the electrode terminal structure of FIG. 5A. 5B is a schematic enlarged cross-sectional view of a circular region A' portion when the case is made thinner in the electrode terminal structure of FIG. 5B. FIG. FIG. 5B is a schematic cross-sectional view showing simulation results for the electrode terminal structure of FIG. 5B. FIG. 5E is a partially enlarged sectional view of the circular region in FIG. 5E. FIG. 7 is a schematic enlarged cross-sectional view of the electrode terminal structure portion of the battery after the rivet portion of the electrode terminal is caulked in another example of the battery of the prior art. 6A is a schematic enlarged cross-sectional view of a circular region B' portion of the electrode terminal structure shown in FIG. 6A. FIG.

[battery]
The present invention provides batteries such as primary batteries and secondary batteries that are equipped with electrode terminals having rivet portions. In this specification, the term "secondary battery" refers to a battery that can be repeatedly charged and discharged. The term "secondary battery" is not excessively limited by its name, and may also include, for example, a "power storage device". The term "primary battery" refers to a battery that can only be discharged. The battery of the present invention is preferably a secondary battery. The present invention is useful for miniaturizing batteries, and this is because the miniaturization of secondary batteries has particularly progressed in recent years.

Hereinafter, the secondary battery of the present invention will be explained in detail using drawings showing some embodiments. The term "cross-sectional view" as used herein refers to a cross-sectional state (cross-sectional view) when viewed from a direction substantially perpendicular to the axial direction of the electrode terminal (particularly the rivet portion thereof). In particular, when the secondary battery has a substantially flat columnar shape as shown in FIG. It may also refer to a cross-sectional state (cross-sectional view) when viewed from a direction substantially perpendicular to the axial direction. "Plane view" refers to the state (plan view) of the electrode terminal (particularly its rivet portion) when viewed from above or below in the axial direction. In this specification, various elements in the drawings are merely shown schematically and illustratively for the purpose of understanding the present invention, and the appearance, dimensional ratio, etc. may differ from the actual elements. Unless otherwise specified, "vertical direction", "horizontal direction", and "front/back direction" used directly or indirectly in this specification correspond to the directions corresponding to the vertical direction, left/right direction, and front/back direction in the drawings, respectively. . Unless otherwise specified, the same reference numerals or symbols indicate the same member or the same meaning except for a different shape.

<First embodiment>
As shown in FIG. 1A, the secondary battery 200 of this embodiment includes an electrode assembly (not shown) and an electrolyte (not shown) in a battery case (hereinafter sometimes simply referred to as "case") 10. is enclosed, and an electrode terminal 20 is led out from inside by the electrode terminal structure 100. The electrode terminal structure 100 is a device for transferring electrons between the inside and outside of the case 10. FIG. 1A is a schematic perspective view showing the appearance of a battery (for example, a secondary battery) according to an embodiment of the present invention.

For example, as shown in FIGS. 1B, 2A, 2B, and 3, the electrode terminal structure 100 includes a case 10, an electrode terminal 20, and a seal member 30 (hereinafter referred to as "first seal member 30"). (1) and a connecting plate 40, and usually further includes an additional sealing member 50 (hereinafter sometimes referred to as "second sealing member 50"). FIG. 1B is a schematic enlarged sectional view of an electrode terminal structure portion of a battery (for example, a secondary battery) according to an embodiment of the present invention before the rivet portion of the electrode terminal is caulked. FIG. 2A is a schematic enlarged sectional view of the electrode terminal structure portion of the battery (for example, a secondary battery) of the present invention shown in FIG. 1B after the rivet portion of the electrode terminal is caulked. FIG. 2B is a schematic enlarged cross-sectional view of a circular region A portion of the electrode terminal structure of FIG. 2A. FIG. 3 is an exploded view of the electrode terminal structure of FIG. 1B.

As shown in FIG. 1B, the secondary battery 200 of this embodiment can be assembled into a case by caulking (for example, compressing in the direction of the arrow) the rivet portion 22 (particularly its tip), as shown in FIGS. 2A and 2B. The cylindrical part 31 of the first sealing member sandwiched between the edging part 12 of 10 and the rivet part 22 of the electrode terminal 20 is appropriately and stably compressed to become a sealing part. Specifically, at this time, the edge of the case 10 has a raised edge portion 12 as described later, and the contact area between the case 10 and the cylindrical portion 31 of the first seal member 30 is such that the case 10 has a raised edge portion 12. This is a sufficient increase compared to the case without it. Therefore, even if an excessive load is applied to the cylindrical portion 31 of the first seal member 30, it is possible to sufficiently prevent the seal member from being damaged. In addition, since the contact area between the case 10 and the cylindrical portion 31 of the first seal member 30 is sufficiently increased, even when the case is deformed due to external loads or changes over time, the case 10 (especially its edge 12) and the sealing member 30 (especially its cylindrical portion 31) can be easily maintained in contact with each other. As a result, it is considered that the sealing performance in the axial direction X is sufficiently improved. In this specification, the sealing property refers to the sealing property between the case 10 and the electrode terminal 20, and is the sealing property to prevent entry of moisture from the outside and leakage of electrolyte from the inside. be. Unless otherwise specified, the sealing property includes the sealing property of the electrode terminal 20 (particularly the rivet portion 22) in the axial direction X and the sealing property in the direction Y perpendicular to the axial direction do. The present invention achieves sufficient improvement in sealing performance, particularly in the axial direction X. Compression of the cylindrical portion 31 includes compression in the direction from the inner circumferential surface to the outer circumferential surface (ie, width direction Y) of the cylindrical portion. Such compression in the inner peripheral surface-outer peripheral surface direction (i.e., width direction Y) of the cylindrical portion 31 is caused by an increase in the cross-sectional width dimension S1 of the rivet portion 22 due to caulking of the rivet portion 22 (i.e., compression in the direction of the arrow in FIG. 1B). This is a compression based on When the rivet portion 22 is columnar or cylindrical, the width direction Y may be the diameter direction thereof.

The present invention is particularly useful when the base portion (ie, the head) 21 of the electrode terminal 20 cannot be made large in order to downsize the battery. In such a case, it is difficult to ensure the compressive force in the axial direction X, and the compressive force in the width direction Y becomes a relatively more important parameter for sealing performance. Therefore, if the case 10 is made thinner for further miniaturization, the sealing member may be damaged at the end of the electrode extraction hole in the case 10 (particularly the end face thereof), and the compressive force in the width direction Y may not be able to be increased, or the external load When the case is deformed due to deformation or changes over time, it may become impossible to maintain contact between the case and the sealing member. Therefore, as in the present invention, by erecting the edge of the electrode terminal extraction hole of the case 10, the contact area between the case and the seal member in the axial direction X is increased, and damage caused by excessive load to the seal member is prevented. In addition, it is possible to maintain contact even when the case is deformed due to external loads or changes over time. As a result, the reliability of the sealing performance (particularly the sealing performance in the axial direction X) can be improved.

In this specification, in FIGS. 1A, 1B, 2A, 4A, etc., the electrode terminal 20 is provided so that the rivet portion 22 penetrates the terminal extraction hole 11 of the case 10 from the outside of the case 10. That is, the electrode terminal 20 is provided so that its pedestal portion 21 is disposed outside the case 10. The present invention is not limited to this embodiment, and it is clear that the effects of the present invention can be obtained even if the arrangement of the outside and inside of the case is reversed. For example, the electrode terminal 20 may be provided such that the rivet portion 22 penetrates the terminal extraction hole 11 of the case 10 from inside the case 10. That is, the electrode terminal 20 may be provided such that its pedestal portion 21 is disposed inside the case 10. In the present invention, from the viewpoint of further improving sealing performance, it is preferable that the electrode terminal 20 is provided such that the rivet portion 22 penetrates the terminal extraction hole 11 of the case 10 from the outside of the case 10.

(Case)
The case 10 is an exterior body that constitutes the external appearance of the secondary battery. The case 10 has a terminal extraction hole 11 (see FIG. 3). In addition, in FIG. 3, only the vicinity of the terminal extraction hole 11 of the case 10 is shown, and other parts are omitted.

The case 10 includes an edge-raised portion 12 on the edge of the terminal extraction hole 11. The edging shape refers to a bent shape in which the edge (that is, the edging portion 12) of the terminal pull-out hole 11 in the case 10 is bent toward the inside of the case 10 in a cross-sectional view. Such a bent shape usually has an L-shape when viewed in cross section. In the edged shape, the edge of the terminal extraction hole in the case 10 (that is, the edge raised portion 12 ) extends along the outer surface 311 of the cylindrical portion 31 of the first seal member 30 . Since the case 10 is provided with the rim 12 at the edge of the terminal extraction hole 11, as described above, the end of the case 10 is prevented from invading the seal member 30 and the seal member 30 is prevented from being damaged due to the intrusion. This allows the sealing performance in the axial direction X to be sufficiently improved. In addition, since the case 10 is provided with the edging part 12 at the edge of the terminal extraction hole 11, as described above, the case 10 (particularly the edging part 12) and the sealing member 30 (particularly the cylindrical part 31) are Since the contact area increases, it becomes easier to maintain these contacts, and the sealing performance in the axial direction X is further improved. If the case does not have a raised edge on the edge of the terminal pull-out hole, the end of the terminal pull-out hole of the case will invade the sealing member and the sealing member will be damaged, resulting in a decrease in sealing performance in the axial direction X. Furthermore, since the contact area between the end of the case and the sealing member (particularly its cylindrical portion) is reduced, it becomes difficult to maintain these contacts, and the sealing performance in the axial direction X is reduced.

The edging part 12 is in a non-embedded state with respect to the sealing member (particularly the second sealing member 50), so that the end face 120 of the edging part 12 is open. When the edging portion 12 is not embedded in the sealing member, it means that the edging portion 12 is not embedded in the sealing member. For example, the edging portion 12 is in a non-embedded state with respect to the first seal member 30 and the second seal member 50. That is, the edging portion 12 is not embedded in either the first seal member 30 or the second seal member 50. Since the edging part 12 is not embedded in the sealing member, even if the edging part 12 moves due to deformation of the case 10 due to external loads or changes over time, the sealing member will not be destroyed, resulting in improved sealing performance. It is possible to prevent a decrease in Such a non-embedded state of the edging portion 12 occurs when the second seal member 50 covers the outer periphery of the cylindrical portion 31 of the first seal member 30, as will be described later. This state is obtained by having a notch 52 (see FIG. 2B) for forming a gap 55 in the groove. If the edging part is embedded in the sealing member, when the edging part 12 moves due to deformation of the case 10 due to external loads or changes over time, the embedded part will be exposed from the sealing member and the seal will be damaged. Since the member is destroyed, the sealing performance (particularly the sealing performance in the axial direction X) deteriorates.

When the end face 120 of the edging part 12 is open, it means that the end face 120 of the edging part 12 is not embedded in any member (for example, a sealing member such as the first sealing member 30 and the second sealing member 50). It is the meaning. Note that the end surface 120 of the edging portion 12 may be in contact with the first seal member 30 and/or the second seal member 50.

The raised edge height H1 (see FIG. 2B) of the raised edge portion 12 is not particularly limited, and is usually 1.5×T1 (μm) or more, 10×T1, where the thickness of the case 10 is T1 (μm). (μm) or less, and from the viewpoint of further improving sealing performance in the axial direction X, preferably 2×T1 (μm) or more and 5×T1 (μm) or less.

The above relationship between the edging height H1 of the edging portion 12 and the thickness T1 of the case 10 indicates that when the secondary battery has a substantially flat columnar shape as shown in FIG. 1A, the cross-sectional area of the secondary battery is maximized. It is only necessary to achieve this in a cross-sectional view when viewed from a direction substantially perpendicular to the axial direction X of the electrode terminal (particularly the rivet portion thereof). The above relationship between the edging height H1 of the edging part 12 and the thickness T1 of the case 10 is based on the above relationship between the edging height H1 of the edging part 12 and the thickness T1 of the case 10. It is preferable that this is also achieved in a cross-sectional view when viewed from any ten directions substantially perpendicular to the axial direction X.

The thickness T1 of the case 10 (see FIG. 2B) is the thickness of the sheet constituting the case, and is not particularly limited, but from the viewpoint of further miniaturization of the battery, it is preferably 100 μm or less (particularly 1 μm or more and less than 100 μm). and more preferably 10 μm or more and 90 μm or less.

The thickness T1 of the case 10 may be an average value of the thicknesses at arbitrary ten locations.

The thickness T2 (see FIG. 2B) of the raised edge portion 12 is usually equal to T1, where the thickness of the case 10 is T1 (μm). Specifically, the expression that the thickness T2 is equal to the thickness T1 means that the thickness T2 is within ±5% of the thickness T1.

The above relationship between the thickness T2 of the edging portion 12 and the thickness T1 of the case 10 is such that when the secondary battery has a substantially flat columnar shape as shown in FIG. 1A, the cross-sectional area of the secondary battery is maximized. , as long as it is achieved in a cross-sectional view when viewed from a direction substantially perpendicular to the axial direction X of the electrode terminal (particularly the rivet portion thereof). The above relationship between the thickness T2 of the edging portion 12 and the thickness T1 of the case 10 is based on the relationship between the thickness T2 of the edge portion 12 and the thickness T1 of the case 10, when the secondary battery has a substantially flat columnar shape as shown in FIG. It is preferable that this is also achieved in cross-sectional view when viewed from any 10 directions substantially perpendicular to the plane.

The cross-sectional width dimension L1 (see FIGS. 1B and 3) of the terminal pull-out hole 11 of the case 10 is usually 1.10×S1 (mm) or more, where the cross-sectional width dimension of the rivet portion 22 is S1 (mm). , 2.00 x S1 (mm) or less, and preferably 1.10 x S1 (mm) or more, 1.50 S1 (mm) or less.

The terminal extraction hole 11 of the case 10 usually has a circular shape, but may have a shape corresponding to the shape of the rivet portion 22 (particularly the shape in plan view). When the terminal extraction hole 11 has a circular shape, the cross-sectional width dimension L1 is the diameter.

The above relationship between the cross-sectional width dimension L1 of the terminal extraction hole 11 of the case 10 and the cross-sectional width dimension S1 of the rivet portion 22 is such that when the secondary battery has a substantially flat column shape as shown in FIG. It is sufficient that the cross-sectional area of the battery is maximized in a cross-sectional view when viewed from a direction substantially perpendicular to the axial direction X of the electrode terminal (particularly the rivet portion thereof). The above relationship between the cross-sectional width dimension L1 of the terminal extraction hole 11 of the case 10 and the cross-sectional width dimension S1 of the rivet portion 22 is such that when the secondary battery has a substantially flat columnar shape as shown in FIG. 1A, the electrode terminal It is preferable that this is also achieved in a cross-sectional view when viewed from any ten arbitrary directions substantially perpendicular to the axial direction X of the rivet portion (particularly the rivet portion).

Case 10 is typically a hard case. For example, case 10 may be constructed from a rigid sheet material. As the hard sheet material constituting the case 10, materials used as constituent materials for cases of secondary batteries can be used, and examples thereof include aluminum, nickel, iron, copper, stainless steel, and the like. In the present invention, the case 10 is preferably made of stainless steel. When the case 10 is made of stainless steel, stainless steel has relatively high strength and can be made thinner. This is because even in such a case, the sealing performance in the axial direction X can be improved. The case 10 may consist of two or more members, such as a lid part and a main body part. When the case consists of two or more members, these members may be joined by laser irradiation or the like.

The case 10 (particularly the edge portion 12 of the case 10) can be manufactured by a processing method such as a press method (for example, a burring method). The edging portion 12 is integrally formed with the case 10. Therefore, the edging portion 12 is made of the same material as the case 10.

(electrode terminal)
The electrode terminal 20 has a pedestal portion 21 whose cross-sectional width dimension is larger than the terminal extraction hole 11 of the case 10 and a rivet portion 22 protruding from the pedestal portion. The electrode terminal 20 is provided so that the rivet portion 22 passes through the terminal extraction hole 11 of the case 10. The electrode terminal 20 may be provided such that the rivet portion 22 penetrates the terminal extraction hole 11 of the case 10 from the outside of the case 10, as shown in FIGS. 1B, 2A, and 3, or It may be provided so as to penetrate from the inside. From the viewpoint of improving conductivity to the battery based on improving connection accuracy with external terminals (not shown), the electrode terminal 20 is designed such that the rivet portion 22 penetrates the terminal extraction hole 11 of the case 10 from the outside of the case 10. It is preferable that it is provided so as to.

The tip of the rivet portion 22 is caulked (FIG. 1B), so that it becomes a caulked portion 220 (see FIG. 2A), for example, on the upper surface of the connection plate 40. The rivet portion 22 may have a columnar shape (that is, solid (for example, cylindrical shape)) or may have a cylindrical shape (for example, cylindrical shape). "Caulking" means compression of the rivet portion in the axial direction X and expansion in the width direction Y (particularly expansion in the width direction Y) due to deformation due to pressure. In the present invention, as a result, compression (particularly compression in the width direction Y) of the cylindrical portion and the flat plate portion (particularly the cylindrical portion in the present invention) of the first seal member is sufficiently achieved between the rivet portion and the case. Therefore, the sealing performance in the axial direction X is sufficiently improved. As shown in FIG. 1B, "caulking" may mean pushing out the tip of the rivet portion 22 by compressing it in the direction of the arrow. In particular, when the rivet part has a cylindrical shape, "crimping" may simply mean deforming it by applying pressure from the inside (for example, expanding it in a cross-sectional shape).

The cross-sectional width dimension S2 (see FIG. 1B) of the pedestal portion 21 is usually 2×S1 (mm) or more and 10×S1 (mm) or less, where the cross-sectional width dimension of the rivet portion 22 is S1 (mm). In view of the balance between further reducing the diameter of the battery and further improving the sealing performance in the axial direction X, it is preferably 4×S1 (mm) or more and 8×S1 (mm) or less.

The shape of the pedestal portion 21 (particularly the shape in plan view) is usually circular, but is not particularly limited. When the pedestal portion 21 has a circular shape, the cross-sectional width dimension S2 is a diameter.

The above relationship between the cross-sectional width dimension S2 of the pedestal portion 21 and the cross-sectional width dimension S1 of the rivet portion 22 is based on the cross-sectional area of the secondary battery when the secondary battery has a substantially flat columnar shape as shown in FIG. 1A. It is only necessary to achieve this in a cross-sectional view when viewed from a direction substantially perpendicular to the axial direction X of the electrode terminal (particularly the rivet portion thereof) so that the The above relationship between the cross-sectional width dimension S2 of the pedestal portion 21 and the cross-sectional width dimension S1 of the rivet portion 22 is such that when the secondary battery has a substantially flat column shape as shown in FIG. It is preferable that this is also achieved in a cross-sectional view when viewed from any ten directions substantially perpendicular to the axial direction X of the portion).

The thickness T3 (see FIGS. 2A and 4A) of the pedestal portion 21 is not particularly limited, and from the viewpoint of further miniaturization of the battery, it is preferably 2000 μm or less (particularly 100 μm or more and less than 2000 μm), and more preferably 500 μm or more and less than 2000 μm. It is as follows.

The cross-sectional width dimension S1 (see FIG. 1B) of the rivet portion 22 is not particularly limited, and is preferably 1 mm or more and 5 mm or less from the viewpoint of balancing further reduction in battery diameter and further improvement of sealing performance in the axial direction X. Yes, and more preferably 1 mm or more and 2 mm or less. The cross-sectional width dimension S1 (see FIG. 1B) of the rivet portion 22 is the dimension before caulking, but can be detected even after caulking. In FIG. 2A, the cross-sectional width dimension of the rivet portion 22 after caulking increases uniformly in the axial direction X compared to before caulking (FIG. 1B), but in the vicinity of the pedestal portion 21, This is because the portion that did not increase remains.

The shape of the rivet portion 22 (particularly the shape in plan view) is usually circular, but is not particularly limited. When the rivet portion 22 has a circular shape, the cross-sectional width dimension S1 is a diameter.

The cross-sectional width dimension S1 of the rivet portion 22 may be an average value of the dimensions at arbitrary ten locations.

The pedestal portion 21 and rivet portion 22 that constitute the electrode terminal 20 may be formed integrally, as shown in FIGS. 1B, 2A, and 3, or may be formed as separate members and then combined. It may be formed as follows.

The pedestal portion 21 may be made of any electrically conductive material. Rivet portion 22 may be constructed from any conductive material that can be caulked. As the conductive material constituting the pedestal part 21 and the rivet part 22, materials used as constituent materials of electrode terminals of secondary batteries can be used, for example, aluminum, nickel, iron, Examples include copper and stainless steel. The pedestal portion 21 and the rivet portion 22 are preferably made of aluminum from the viewpoint of achieving a balance between further reducing the diameter of the battery and further improving sealing performance in the axial direction X.

The electrode terminal 20 can be manufactured by a processing method such as a forging method, a cutting method, an extrusion method, or a combination of these processing methods.

(First seal member)
The first sealing member 30 is provided between the case 10 and the electrode terminal 20 and seals the gap between the case 10 and the electrode terminal 20. The first seal member 30 normally ensures insulation between the case 10 and the electrode terminal 20.

The first seal member 30 has a cylindrical portion 31 that is attached to the outer periphery of the rivet portion 22 of the electrode terminal 20 and a flat plate portion 32 that extends in the outer radial direction from one end of the cylindrical portion. The first seal member 30 is provided such that the flat plate portion 32 is disposed on the outside of the case 10 (particularly on the outside surface of the case 10) in FIGS. 1B, 2A, and the like. 1B and 2A, the base portion 21 of the electrode terminal 20 is disposed outside the case 10, so the first seal member 30 has a flat plate portion 32 located outside the case 10 (particularly on the outside surface of the case 10). It is arranged so that it is placed in the The flat plate part 32 of the first sealing member 30 is usually arranged on the outside or inside of the case 10 on the side where the pedestal part 21 of the electrode terminal 20 is arranged. For example, when the base portion 21 of the electrode terminal 20 is placed inside the case 10, the flat plate portion 32 of the first seal member 30 is placed inside the case 10 (particularly on the inside surface of the case 10).

The cylindrical portion 31 is provided above the flat plate portion 32, and the flat plate portion 32 extends in the outer radial direction from one end (lower end) of the cylindrical portion 31 in a flat plate shape (for example, a disk shape). The cylindrical portion 31 is attached to the outer periphery of the rivet portion 22 of the electrode terminal 20 and inserted into the terminal extraction hole 11 together with the rivet portion 22 . The flat plate part 32 extends from the terminal extraction hole 11 along the surface of the case 10 (the outside (particularly the outside surface) of the case 10 in FIG. 21 (in FIG. 1B and the like, between the outer surface of the case 10 and the base portion 21 of the electrode terminal 20).

The height (not shown) of the cylindrical portion 31 is not particularly limited, and is usually 10×T1 (μm) or more (especially 10× T1 (μm) or more and 100000×T1 (μm) or less), and preferably from 100×T1 (μm) or more and 10000×T1 (μm) or less from the viewpoint of further improving sealing performance in the axial direction X.

The cross-sectional width dimension S3 (see FIG. 1B) of the flat plate portion 32 is usually 1.1×L1 (mm) or more, 10×L1 (mm), where the cross-sectional width dimension of the terminal extraction hole 11 is L1 (mm). ) or less, and from the viewpoint of a balance between further reducing the diameter of the battery and further improving the sealing performance in the width direction Y, it is preferably 1.5×L1 (mm) or more and 3×L1 (mm) or less.

The shape of the flat plate portion 32 (particularly the shape in plan view (for example, the outer edge shape in plan view)) is usually circular, but is not particularly limited. When the flat plate portion 32 has a circular shape, the cross-sectional width dimension S3 is a diameter.

The above relationship between the cross-sectional width dimension S3 of the flat plate portion 32 and the cross-sectional width dimension L1 of the terminal extraction hole 11 is such that when the secondary battery has a substantially flat columnar shape as shown in FIG. 1A, the disconnection of the secondary battery is It is sufficient that the area is maximized in a cross-sectional view when viewed from a direction substantially perpendicular to the axial direction X of the electrode terminal (particularly the rivet portion thereof). The above relationship between the cross-sectional width dimension S3 of the flat plate portion 32 and the cross-sectional width dimension L1 of the terminal extraction hole 11 is such that when the secondary battery has a substantially flat columnar shape as shown in FIG. It is preferable that this is also achieved in cross-sectional view when viewed from any ten arbitrary directions substantially perpendicular to the axial direction X of the rivet portion).

The thickness T4 (see FIG. 2A) of the cylindrical portion 31 and the thickness T5 (see FIG. 2A) of the flat plate portion 32 are usually each independently 0.1 mm or more and 2 mm or less. From the viewpoint of balance between further improvement of sealing properties, the thickness is preferably 0.2 mm or more and 0.5 mm or less.

The thickness T4 of the cylindrical portion 31 and the thickness T5 of the flat plate portion 32 may each be an average value of the thicknesses at arbitrary ten locations.

The cylindrical portion 31 and the flat plate portion 32 may be formed integrally, as shown in FIGS. 1B, 2A, and 3, or may be formed by combining separate members. Good too.

The cylindrical portion 31 and the flat plate portion 32 may be each independently made of any elastic material having insulation properties. As the elastic materials constituting the cylindrical portion 31 and the flat plate portion 32, materials used as constituent materials of sealing members or gaskets of secondary batteries can be used, for example, fluororubber (e.g. Fluororubbers such as tetrafluoroethylene/perfluoroalkyl vinyl ether copolymer (PFA), vinylidene fluoride (FKM), tetrafluoroethylene-propylene (FEPM), ethylene-propylene rubber (EPM), ethylene-propylene - Rubber materials such as diene copolymer rubber (EPDM) and butyl rubber can be mentioned. The cylindrical portion 31 and the flat plate portion 32 are preferably made of PFA from the viewpoint of a balance between further reducing the diameter of the battery and further improving sealing performance in the axial direction X.

The first seal member 30 can be manufactured by a molding method such as an injection molding method or a blow molding method.

(Connection plate)
The connection plate 40 is a member that electrically connects an electrode (not shown) (usually one of a positive electrode or a negative electrode) inside the case 10 to the electrode terminal 20. The connection plate 40 usually has a terminal extraction hole 41 (see FIG. 3), and the rivet portion 22 is inserted into the terminal extraction hole 41 to be attached to the outer periphery of the rivet portion 22. Although the connection plate 40 has a flat plate shape in FIGS. 1B, 2A, and 3, it may have any shape as long as it is electrically connected to the electrode inside the case 10.

The cross-sectional width dimension L2 (see FIGS. 2A and 3) of the terminal extraction hole 41 of the connection plate 40 is usually 1.01×S1 (mm), where the cross-sectional width dimension of the rivet portion 22 is S1 (mm). The above is 1.25 x S1 (mm) or less, and from the viewpoint of a balance between further reducing the diameter of the battery and further improving sealing performance in the axial direction X, preferably 1.08 x S1 (mm) or more and 1.18 ×S1 (mm) or less.

The terminal extraction hole 41 of the connection plate 40 usually has a circular shape, but may have a shape corresponding to the shape of the rivet portion 22 (particularly the shape in plan view). When the terminal extraction hole 41 has a circular shape, the cross-sectional width dimension L2 is the diameter. Note that the inner circumferential surface of the terminal extraction hole 41 in the connecting plate 40 is normally flush with the inner circumferential surface of the cylindrical portion 31 in the first sealing member 30, but as long as sealing performance is ensured, There may be a step (for example, a step of T4 or less).

The above relationship between the cross-sectional width dimension L2 of the terminal pull-out hole 41 of the connection plate 40 and the cross-sectional width dimension S1 of the rivet portion 22 is the same as the above relationship when the secondary battery has a substantially flat columnar shape as shown in FIG. 1A. It is sufficient that the cross-sectional area of the secondary battery is maximized in a cross-sectional view when viewed from a direction substantially perpendicular to the axial direction X of the electrode terminal (particularly the rivet portion thereof). The above relationship between the cross-sectional width dimension L2 of the terminal extraction hole 41 of the connection plate 40 and the cross-sectional width dimension S1 of the rivet portion 22 is such that when the secondary battery has a substantially flat columnar shape as shown in FIG. 1A, the electrode It is preferable that this is also achieved in a cross-sectional view when viewed from any ten arbitrary directions substantially perpendicular to the axial direction X of the terminal (particularly the rivet portion thereof).

Connection plate 40 may be constructed from any electrically conductive material. As the conductive material constituting the connection plate 40, materials used as constituting materials for connection plates of secondary batteries can be used, and examples thereof include aluminum, nickel, iron, copper, stainless steel, and the like. The connection plate 40 is preferably made of aluminum from the viewpoint of achieving a balance between further reducing the diameter of the battery and further improving the sealing performance in the axial direction X.

The connection plate 40 can be manufactured by a processing method such as a press method or a cutting method.

(Second seal member)
The second seal member 50 is provided between the case 10 and the connection plate 40 and seals the gap between the case 10 and the connection plate 40. The second seal member 50 normally ensures insulation between the case 10 and the connection plate 40.

The second seal member 50 usually has a terminal extraction hole 51 (see FIG. 3). The second seal member 50 is attached to the outer periphery of the cylindrical portion 31 of the first seal member 30 by inserting the rivet portion 22 to which the first seal member 30 is attached into the terminal extraction hole 51 . As a result, the second seal member 50 is arranged inside the case 10 (particularly on the inner surface of the case 10) so as to cover the outer periphery of the cylindrical portion 31 of the first seal member 30, as shown in FIGS. 1B and 2A. It is set up like this. 1B and 2A, the pedestal portion 21 of the electrode terminal 20 is placed on the outside of the case 10, so the second seal member 50 is placed on the inside of the case 10 (particularly on the inside surface of the case 10). There is. The second seal member 50 is usually arranged on the outside or inside of the case 10 on the side opposite to the side on which the pedestal part 21 of the electrode terminal 20 is arranged. For example, when the pedestal portion 21 of the electrode terminal 20 is arranged inside the case 10, the second seal member 50 is arranged outside the case 10 (particularly on the outer surface of the case 10).

The second seal member 50 usually has a notch 52 on the inner peripheral surface of the terminal extraction hole 51, as shown in FIG. 2B. Therefore, when the second seal member 50 covers the outer periphery of the cylindrical portion 31 of the first seal member 30, a gap 55 is formed between the second seal member 50 and the first seal member 30. For this reason, the above-described non-embedded state of the edge portion 12 of the case 10 and its end surface 120 is brought about.

Although the cutout portion 52 of the second seal member 50 has a rectangular cross-sectional shape in FIG. 2B, the shape is not limited to this. It may have any cross-sectional shape as long as the section 12 is accommodated.

The cross-sectional width dimension (not shown) of the terminal extraction hole 51 of the second seal member 50 may correspond to the outer diameter dimension of the cylindrical portion 31 of the first seal member 30. At this time, the cross-sectional width dimension (not shown) of the terminal extraction hole 51 of the second seal member 50 usually corresponds to the cross-sectional width dimension L1 of the terminal extraction hole 11 of the case 10.

The second seal member 50 may be made of the same material as the first seal member 30. The second seal member 50 is preferably made of PFA from the viewpoint of achieving a balance between further reducing the diameter of the battery and further improving sealing performance in the axial direction X.

The second seal member 50 can be manufactured by a molding method such as an injection molding method or a blow molding method.

(Other components of secondary battery)
An electrode assembly (not shown) typically includes a positive electrode, a negative electrode, and a separator disposed between the positive and negative electrodes. In the electrode assembly, positive electrodes and negative electrodes are alternately arranged with separators in between. The structure of the electrode assembly is not particularly limited. For example, the electrode assembly may have a laminated structure (planar layered structure), a wound structure (jellyroll structure), or a stack-and-fold structure. Specifically, for example, the electrode assembly has a planar layered structure in which one or more electrode units (electrode constituent layers) including a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode are laminated in a planar manner. It may have. For example, the electrode assembly has a wound structure (jelly roll type) in which an electrode unit (electrode constituent layer) including a positive electrode, a negative electrode, and a separator arranged between the positive electrode and the negative electrode is wound into a roll. You can leave it there. For example, the electrode assembly may have a so-called stack-and-fold structure in which a positive electrode, a separator, and a negative electrode are stacked on a long film and then folded. The secondary battery of the present invention preferably has a wound structure from the viewpoint of further miniaturization of the battery.

When a secondary battery has a substantially flat columnar shape as shown in FIG. 1A and an electrode assembly used in the secondary battery has a wound structure, the electrode assembly also has a substantially flat columnar shape. There is. A wound electrode assembly having a substantially flat columnar shape can be obtained, for example, by pressing an electrode assembly having a substantially cylindrical shape in its diameter direction.

The positive electrode is composed of at least a positive electrode material layer and a positive electrode current collector (foil), and it is sufficient that the positive electrode material layer is provided on at least one side of the positive electrode current collector. For example, in the positive electrode, a positive electrode material layer may be provided on both sides of a positive electrode current collector, or a positive electrode material layer may be provided on one side of the positive electrode current collector. From the viewpoint of further increasing the capacity of the secondary battery, a preferred positive electrode has positive electrode material layers provided on both sides of a positive electrode current collector. The positive electrode material layer contains a positive electrode active material.

The negative electrode is composed of at least a negative electrode material layer and a negative electrode current collector (foil), and it is sufficient that the negative electrode material layer is provided on at least one side of the negative electrode current collector. For example, in the negative electrode, negative electrode material layers may be provided on both sides of a negative electrode current collector, or a negative electrode material layer may be provided on one side of the negative electrode current collector. From the viewpoint of further increasing the capacity of the secondary battery, a preferred negative electrode has negative electrode material layers provided on both sides of a negative electrode current collector. The negative electrode material layer contains a negative electrode active material.

The positive electrode active material contained in the positive electrode material layer and the negative electrode active material contained in the negative electrode material layer are substances directly involved in the transfer of electrons in secondary batteries, and are the main materials of the positive and negative electrodes responsible for charging and discharging, that is, battery reactions. be. More specifically, ions are brought into the electrolyte due to "the positive electrode active material contained in the positive electrode material layer" and "the negative electrode active material contained in the negative electrode material layer", and these ions are brought into contact between the positive electrode and the negative electrode. The battery moves and exchanges electrons to perform charging and discharging. The positive electrode and the negative electrode are preferably electrodes capable of intercalating and deintercalating lithium ions, that is, the positive electrode material layer and the negative electrode material layer are preferably layers capable of intercalating and deintercalating lithium ions. In other words, a secondary battery in which lithium ions move between a positive electrode and a negative electrode via an electrolyte to charge and discharge the battery is preferable. When lithium ions are involved in charging and discharging, the secondary battery according to this embodiment corresponds to a so-called "lithium ion battery."

The positive electrode active material of the positive electrode material layer is composed of, for example, granules, and it is preferable that a binder is included in the positive electrode material layer for sufficient contact between the particles and shape retention. Furthermore, it is also preferable that a conductive agent is included in the positive electrode material layer in order to facilitate the transmission of electrons that promote battery reactions. Similarly, when the negative electrode active material of the negative electrode material layer is composed of, for example, granules, it is preferable that a binder is included for sufficient contact between the particles and for shape retention, and for smooth transmission of electrons that promote battery reactions. A conductive additive may be included in the negative electrode material layer to achieve this. As described above, since a plurality of components are contained, the positive electrode material layer and the negative electrode material layer can also be referred to as a "positive electrode composite material layer" and a "negative electrode composite material layer," respectively.

The positive electrode active material is preferably a material that contributes to intercalation and desorption of lithium ions. From this point of view, it is preferable that the positive electrode active material is, for example, a lithium-containing composite oxide. More specifically, the positive electrode active material is preferably a lithium transition metal composite oxide containing lithium and at least one transition metal selected from the group consisting of cobalt, nickel, manganese, and iron. That is, in the positive electrode material layer of the secondary battery according to this embodiment, such a lithium transition metal composite oxide is preferably contained as a positive electrode active material. For example, the positive electrode active material may be lithium cobalt oxide, lithium nickel oxide, lithium manganate, iron reseparate phosphate, or a material in which some of the transition metals thereof are replaced with another metal. Although such positive electrode active materials may be contained as a single species, they may be contained in a combination of two or more types. In a more preferred embodiment, the positive electrode active material contained in the positive electrode material layer is lithium cobalt oxide.

Binders that may be included in the positive electrode material layer include, but are not particularly limited to, polyvinidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, and At least one selected from the group consisting of polytetrafluoroethylene and the like can be mentioned. Conductive additives that may be included in the positive electrode material layer include, but are not particularly limited to, carbon blacks such as thermal black, furnace black, channel black, Ketjen black, and acetylene black, graphite, carbon nanotubes, and vapor phase growth. Examples include at least one selected from carbon fibers such as carbon fibers, metal powders such as copper, nickel, aluminum and silver, and polyphenylene derivatives. In a more preferred embodiment, the binder of the positive electrode material layer is polyvinylidene fluoride, and in another more preferred embodiment, the conductive additive of the positive electrode material layer is carbon black. In a further preferred embodiment, the binder and conductive additive of the positive electrode material layer are a combination of polyvinylidene fluoride and carbon black.

The thickness of the positive electrode material layer is not particularly limited, and may be, for example, 1 μm or more and 300 μm or less, particularly 5 μm or more and 200 μm or less. The thickness of the positive electrode material layer is the thickness inside the secondary battery, and the average value of the measured values at 50 arbitrary locations is used.

The negative electrode active material is preferably a material that contributes to intercalation and desorption of lithium ions. From this point of view, the negative electrode active material is preferably, for example, various carbon materials, oxides, lithium alloys, or the like.

Various carbon materials for the negative electrode active material include graphite (natural graphite, artificial graphite), hard carbon, soft carbon, diamond-like carbon, and the like. In particular, graphite is preferable because it has high electronic conductivity and excellent adhesion to the negative electrode current collector. Examples of the oxide of the negative electrode active material include at least one selected from the group consisting of silicon oxide, tin oxide, indium oxide, zinc oxide, lithium oxide, and the like. The lithium alloy of the negative electrode active material may be any metal that can be alloyed with lithium, such as Al, Si, Pb, Sn, In, Bi, Ag, Ba, Ca, Hg, Pd, Pt, Te, Zn, It may be a binary, ternary or higher alloy of metal such as La and lithium. Preferably, such an oxide has an amorphous structure. This is because deterioration caused by non-uniformity such as grain boundaries or defects is less likely to occur. In a more preferred embodiment, the negative electrode active material of the negative electrode material layer is artificial graphite.

The binder that may be included in the negative electrode material layer is not particularly limited, but at least one member selected from the group consisting of styrene-butadiene rubber, polyacrylic acid, polyvinylidene fluoride, polyimide resin, and polyamideimide resin. can be mentioned. In a more preferred embodiment, the binder contained in the negative electrode material layer is styrene-butadiene rubber. Conductive additives that may be included in the negative electrode material layer include, but are not particularly limited to, carbon blacks such as thermal black, furnace black, channel black, Ketjen black, and acetylene black, graphite, carbon nanotubes, and vapor-phase growth. Examples include at least one selected from carbon fibers such as carbon fibers, metal powders such as copper, nickel, aluminum and silver, and polyphenylene derivatives. Note that the negative electrode material layer may contain a component resulting from a thickener component (for example, carboxymethylcellulose) used during battery manufacture.

In a further preferred embodiment, the negative electrode active material and binder in the negative electrode material layer are a combination of artificial graphite and styrene-butadiene rubber.

The thickness of the negative electrode material layer is not particularly limited, and may be, for example, 1 μm or more and 300 μm or less, particularly 5 μm or more and 200 μm or less. The thickness of the negative electrode material layer is the thickness inside the secondary battery, and the average value of the measured values at 50 arbitrary locations is used.

A positive electrode current collector and a negative electrode current collector used in a positive electrode and a negative electrode are members that help collect and supply electrons generated in an active material due to a battery reaction. Such a current collector may be a sheet-like metal member and may have a porous or perforated form. For example, the current collector may be metal foil, punched metal, mesh, expanded metal, or the like. The positive electrode current collector used in the positive electrode is preferably made of a metal foil containing at least one selected from the group consisting of aluminum, stainless steel, nickel, etc., and may be, for example, an aluminum foil. On the other hand, the negative electrode current collector used in the negative electrode is preferably made of a metal foil containing at least one selected from the group consisting of copper, stainless steel, nickel, etc., and may be a copper foil, for example.

The separator is a member provided from the viewpoint of preventing short circuits due to contact between positive and negative electrodes and retaining electrolyte. In other words, the separator can be said to be a member that allows ions to pass through while preventing electronic contact between the positive electrode and the negative electrode. Preferably, the separator is a porous or microporous insulating member, which has a membrane form due to its small thickness. By way of example only, a microporous membrane made of polyolefin may be used as the separator. In this regard, the microporous membrane used as the separator may contain, for example, only polyethylene (PE) or polypropylene (PP) as the polyolefin. Furthermore, the separator may be a laminate composed of a "microporous membrane made of PE" and a "microporous membrane made of PP." The surface of the separator may be covered with an inorganic particle coating layer and/or an adhesive layer. The surface of the separator may have adhesive properties.

The thickness of the separator is not particularly limited, and may be, for example, 1 μm or more and 100 μm or less, particularly 5 μm or more and 20 μm or less. The thickness of the separator is the thickness inside the secondary battery (particularly the thickness between the positive electrode and the negative electrode), and the average value of the measured values at 50 arbitrary locations is used.

The electrolyte assists in the movement of metal ions released from the electrodes (positive and negative electrodes). The electrolyte may be a "non-aqueous" electrolyte such as an organic electrolyte and an organic solvent, or an "aqueous" electrolyte containing water. The secondary battery of the present invention is preferably a non-aqueous electrolyte secondary battery in which an electrolyte containing a "non-aqueous" solvent and a solute is used as the electrolyte. The electrolyte may have a liquid or gel form (in this specification, a "liquid" non-aqueous electrolyte is also referred to as a "non-aqueous electrolyte solution").

The specific solvent for the non-aqueous electrolyte is not particularly limited, but preferably contains at least carbonate. Such carbonates may be cyclic carbonates and/or linear carbonates. Although not particularly limited, examples of the cyclic carbonates include at least one selected from the group consisting of propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate (BC), and vinylene carbonate (VC). be able to. Examples of chain carbonates include at least one selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate (DEC), ethylmethyl carbonate (EMC), and dipropyl carbonate (DPC). In one preferred embodiment of the invention, a combination of cyclic carbonates and linear carbonates is used as the non-aqueous electrolyte, for example a mixture of ethylene carbonate and diethyl carbonate.
As a specific solute of the non-aqueous electrolyte, for example, Li salts such as LiPF ₆ and LiBF ₄ are preferably used.

<Second embodiment>
The secondary battery of this embodiment is the same as the secondary battery 200 of the first embodiment except that it has the following electrode terminal structure 100'.
The electrode terminal structure 100' is the same as the electrode terminal structure 100 in the secondary battery 200 of the first embodiment, except that it includes a case 10a instead of the case 10, as shown in FIGS. 4A and 4B. FIG. 4A is a schematic enlarged sectional view of an electrode terminal structure portion of a battery (for example, a secondary battery) according to another embodiment of the present invention after the rivet portion of the electrode terminal is caulked. FIG. 4B is a schematic enlarged sectional view of a circular region B portion of the electrode terminal structure of FIG. 4A.

In detail, the case 10a is the same as the case 10, except that the raised edge portion 12a is constructed as a separate component, as shown in FIGS. 4A and 4B. By configuring the edging portion 12a as a separate component, it becomes easy to form the edging portion 12a in the case 10a, and the manufacturing cost is sufficiently reduced.

In the case 10a, the edging portion 12a and other parts can be connected to each other by a laser irradiation method or the like.

As the material constituting the case 10a and the edging portion 12a, the hard sheet material constituting the case 10 in the first embodiment can be used independently, such as aluminum, nickel, iron, copper, stainless steel, etc. Can be mentioned. In this embodiment, the case 10a and the edging portion 12a are preferably made of stainless steel.

The secondary battery according to the present invention can be used in various fields where power storage is expected. Although this is merely an example, the secondary battery according to the present invention, particularly the nonaqueous electrolyte secondary battery, can be used in the electrical, information, and communication fields where mobile devices are used (e.g., mobile phones, smartphones, smart watches, laptop computers, etc.). , digital cameras, activity monitors, arm computers, electronic paper, and other mobile devices), household and small industrial applications (e.g., power tools, golf carts, household, nursing care, and industrial robots), and large industrial applications. (e.g., forklifts, elevators, harbor cranes), transportation systems (e.g., hybrid vehicles, electric vehicles, buses, trains, electrically assisted bicycles, electric motorcycles, etc.), power system applications (e.g., various power generation, road conditioners, smart grids, general home-installed energy storage systems, etc.), medical applications (medical devices such as earphones and hearing aids), pharmaceutical applications (medication management systems, etc.), IoT fields, and space/deep sea applications. (For example, in the field of space probes, underwater research vessels, etc.).

10: 10a: Case 11: Terminal extraction hole of case 12: 12a: Edge holder 20: Electrode terminal 21: Pedestal portion 22: Rivet portion 30: First seal member 31: Cylindrical portion 32: Flat plate portion 40: Connection plate 41 : Terminal extraction hole of connection plate 50: Second seal member 51: Terminal extraction hole of second seal member 100: 100': Electrode terminal structure 200: Secondary battery

Claims (20)

an electrode assembly including an electrode;
a case that houses the electrode assembly and has a terminal extraction hole;
an electrode terminal having a pedestal part and a rivet part protruding from the pedestal part, the rivet part being provided so as to pass through a terminal extraction hole of the case;
A sealing member is provided between the case and the electrode terminal, and seals a gap between the case and the electrode terminal, and is attached to the outer periphery of the rivet part , and is attached to the terminal extraction hole together with the rivet part. It has a cylindrical part inserted into the cylindrical part and a flat plate part extending in the outer radial direction from one end of the cylindrical part, and the flat part has a pedestal part of the electrode terminal on the outside or inside of the case. a sealing member provided on the side where the sealing member is placed;
a connection plate that electrically connects the electrode inside the case to the electrode terminal, the connection plate being attached to the outer periphery of the rivet portion;
Equipped with
The battery is characterized in that the case includes a raised edge portion on the edge of the terminal pull-out hole. Claim: By caulking the tip of the rivet part, at least the cylindrical part of the sealing member sandwiched between the edging part of the case and the rivet part of the electrode terminal is compressed and becomes a sealing part. 1. The battery according to 1. 3. The battery according to claim 2, wherein the compression of the cylindrical portion includes compression in a direction from an inner circumferential surface to an outer circumferential surface of the cylindrical portion. 4. The battery according to claim 3, wherein the compression in the direction from the inner circumferential surface to the outer circumferential surface of the cylindrical portion is based on an increase in the cross-sectional width dimension S1 of the rivet portion due to the caulking. The pedestal portion is arranged outside the case,
The battery according to any one of claims 1 to 4, wherein the edging portion extends toward the inside of the case and along the outer surface of the cylindrical portion of the sealing member in a cross-sectional view. . The battery according to any one of claims 1 to 5, wherein the edging portion is not embedded in the sealing member. The battery according to any one of claims 1 to 6, wherein an end surface of the edge-standing portion is open. The edging portion has a edging height H1 of 1.5×T1 or more and 10×T1 or less, where T1 is the thickness of the case. battery. The battery according to any one of claims 1 to 8, wherein the edging portion has a thickness T2 equal to T1, where T1 is the thickness of the case. The battery further includes a further sealing member,
The further sealing member is a sealing member that is provided between the case and the connection plate and seals a gap between the case and the connection plate, the sealing member having the cylindrical part and the flat plate part. Any one of claims 1 to 9, wherein the electrode terminal is disposed on the outside or inside of the case, on the side opposite to the side on which the pedestal part of the electrode terminal is arranged, so as to cover the outer periphery of the cylindrical part. Batteries listed. 11. The battery of claim 10, wherein the rim is non-embedded with respect to the further sealing member. The battery according to any one of claims 1 to 11, wherein the case has a thickness T1 of 100 μm or less. The pedestal portion of the electrode terminal has a cross-sectional width dimension S2 of 2×S1 (mm) or more and 10×S1 (mm) or less, where the cross-sectional width dimension of the rivet portion is S1 (mm). The battery according to any one of claims 1 to 12. The terminal draw-out hole of the case has a cross-sectional width dimension L1 of 1.10×S1 (mm) or more and 2.00×S1 (mm) or less, where the cross-sectional width dimension of the rivet part is S1 (mm). The battery according to any one of claims 1 to 13, comprising: 15. The battery according to claim 1, wherein the electrode terminal is provided such that the rivet portion penetrates a terminal extraction hole of the case from outside the case. The battery according to any one of claims 1 to 15, wherein the case is a hard case. The case is a hard case,
The case has a thickness T1 of 100 μm or less,
The pedestal portion of the electrode terminal has a cross-sectional width dimension S2 of 2×S1 (mm) or more and 10×S1 (mm) or less, where the cross-sectional width dimension of the rivet portion is S1 (mm). The battery according to any one of claims 1 to 16. The battery according to any one of claims 1 to 17, wherein the battery is a secondary battery in which the electrode assembly and electrolyte are enclosed in the case. 19. The battery of claim 18, wherein the electrolyte is a non-aqueous electrolyte. The electrode includes a positive electrode and a negative electrode,
The secondary battery according to claim 18 or 19, wherein the positive electrode and the negative electrode are electrodes capable of inserting and extracting lithium ions.

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