Sealed battery and sealed battery manufacturing method

A first terminal including an insertion hole is placed on one side of a lid of a battery case with one or more insulating materials interposed therebetween. An inner circumferential surface defining the insertion hole includes a first rim and a second rim at a position farther away from the one or more insulating materials than the first rim is. The second rim includes an inclined surface with a recess that includes a bottom at a position set back inside the first terminal from the inclined surface. The second terminal has a shaft part inserted through a mounting hole of the lid and the insertion hole. A leading end of the shaft part is riveted, and at least a portion of the shaft part reaches into the recess.

INCORPORATION BY REFERENCE

The disclosure of Japanese Patent Application No. 2016-219192 filed on Nov. 9, 2016 including the specification, drawings and abstract is incorporated herein by reference in its entirety.

BACKGROUND

1. Technical Field

The present disclosure relates to a sealed battery and a sealed battery manufacturing method.

2. Description of Related Art

Japanese Unexamined Patent Application Publication No. 2009-259524 discloses a mounting structure of a terminal of a battery case including a lid body of the battery case, a first terminal, and a rivet member (also called a second terminal or a collector terminal). Here, the lid body of the battery case and the first terminal each have a hole formed therein. The rivet member is a member that is attached from inside the battery case, and has a cylindrical part and a collar part. The cylindrical part is inserted through the hole formed in the lid body and the hole formed in the first terminal. A leading end of the cylindrical part is pushed out and deformed so as to be pressed against a periphery of the hole in the first terminal. Thus, the lid body and the first terminal are fixed while held between the collar part and the portion formed by pushing out the leading end (riveted portion) of the rivet member. Thereafter, a part of the riveted portion and the first terminal are welded together.

SUMMARY

According to the knowledge of the present inventors, under severe conditions such as where the battery is subjected to vibration or shock accompanied by a high rate of acceleration, especially in an ultralow temperature environment that can arise in frigid regions, the rivet member and the terminal can partially come apart at the joint and cause a rise in resistance. It is desirable that the rivet member and the terminal be joined together more firmly.

A first aspect of the present disclosure relates to a sealed battery. The sealed battery includes a battery case, one or more insulating materials, a metal first terminal, and a metal second terminal. The battery case includes a mounting hole. The one or more insulating materials are provided around the mounting hole. The metal first terminal is placed on one side of the battery case with the one or more insulating materials interposed between the battery case and the first terminal, and has an insertion hole at a position corresponding to the mounting hole. An inner circumferential surface of the first terminal defining the insertion hole has a first rim and a second rim at a position farther away from the one or more insulating materials than the first rim is. The second rim includes an inclined surface. A diameter of the insertion hole at the inclined surface increases gradually in a direction away from the one or more insulating materials. The inclined surface includes an open recess. The recess includes a bottom at a position set back inside the first terminal from the inclined surface. The metal second terminal is placed on other side of the battery case opposite to the one side with the insulating materials interposed between the battery case and the second terminal. The second terminal has a shaft part. The shaft part is inserted through the mounting hole and the insertion hole. A leading end of the shaft part is crushed and riveted on the first terminal. At least a portion of the shaft part reaches into the recess in the inclined surface of the first terminal.

Moreover, in the first aspect of the present disclosure, the first terminal and the second terminal may be made of different materials. In this case, the first terminal and the second terminal are made of different materials and therefore have different coefficients of expansion and contraction relative to temperature changes, but the above configuration does not allow the first terminal and the second terminal to easily come apart at the joint.

Moreover, in the first aspect of the present disclosure, the width of the recess may be, for example, within a range from 0.1 mm to 0.3 mm. The depth of the recess may be, for example, within a range from 0.3 mm to 0.7 mm.

Moreover, in the first aspect of the present disclosure, the first terminal may be placed on an outer side of the battery case.

Moreover, in the first aspect of the present disclosure, the first terminal may be placed on an inner side of the battery case.

A second aspect of the present disclosure relates to a sealed battery manufacturing method. A battery case having a mounting hole, a metal first terminal including an insertion hole, a metal second terminal including a shaft part that is insertable through the mounting hole and the insertion hole, and one or more insulating materials are prepared. Next, the first terminal is placed on one side of the battery case. Here, the one or more insulating materials are interposed between the battery case and the first terminal, and the mounting hole and the insertion hole are aligned with each other. Moreover, the second terminal is placed on other side of the battery case opposite to the one side. Here, the one or more insulating materials are interposed between the battery case and the second terminal, and the shaft part is inserted through the mounting hole and the insertion hole. Then, a leading end of the shaft part is crushed, and the leading end is riveted on the first terminal. Here, an inner circumferential surface of the prepared first terminal defining the insertion hole includes a first rim and a second rim at a position farther away from the one or more insulating materials than the first rim is. The second rim includes an inclined surface. A diameter of the insertion hole at the inclined surface increases gradually in a direction away from the insulating materials. The inclined surface includes an open recess. The recess has a bottom at a position set back inside the first terminal from the inclined surface. In the riveting process, a portion of the shaft part reaches into the recess in the inclined surface of the first terminal.

Moreover, in the second aspect of the present disclosure, the leading end of the shaft part may include a cylindrical shape. In the riveting process, a rotating member may be pressed against the cylindrical leading end of the shaft part while being moved along the leading end in a circumferential direction of the insertion hole.

Moreover, in the second aspect of the present disclosure, the first terminal and the second terminal may be made of different materials. The width of the recess may be, for example, within a range from 0.1 mm to 0.3 mm. The depth of the recess may be, for example, within a range from 0.3 mm to 0.7 mm.

DETAILED DESCRIPTION OF EMBODIMENTS

An embodiment of a sealed battery proposed herein will be described below. It should be understood that the embodiment described herein is not intended to limit the present disclosure. Unless otherwise mentioned, the disclosure is not limited to the embodiment described herein. The drawings are schematic views and do not necessarily exactly represent the actual components.

FIG. 1is a partial sectional view of a sealed battery10according to the embodiment of the present disclosure.FIG. 1depicts a state where an inside of a substantially cuboid battery case11is exposed along a wider surface on one side thereof.FIG. 2is a sectional view showing a part where a first terminal14and a second terminal15are mounted on the battery case11. As shown inFIG. 1andFIG. 2, the sealed battery10includes the battery case11, insulating materials12,13, the first terminals14, the second terminals15, and an electrode body16.

Here, as shown inFIG. 1, the first terminals14and the second terminals15are mounted on the battery case11through the insulating materials12,13. The electrode body16and an electrolyte solution are housed inside the battery case11. The electrode body16is housed inside the battery case11while covered with an insulating film etc. (not shown). Thus, the electrode body16is insulated from the battery case11. The electrode body16includes a positive electrode element, a negative electrode element, and separators of the sealed battery10.

In this embodiment, the electrode body16includes a positive electrode sheet21as the positive electrode element, a negative electrode sheet22as the negative electrode element, and separator sheets31,32as the separators. The positive electrode sheet21, the first separator sheet31, the negative electrode sheet22, and the second separator sheet32are long band-like members.

The positive electrode sheet21has a positive electrode collector foil21a(e.g., an aluminum foil) of predetermined width and thickness, on each side of which a positive electrode active material layer21bcontaining a positive electrode active material is formed except for a blank portion21a1that is provided at a constant width at one end of the positive electrode collector foil21ain a width direction. For example, in a lithium-ion secondary battery, the positive electrode active material is a material such as a lithium transition metal composite material that can release lithium ions during charge and absorb lithium ions during discharge. However, the positive electrode active material is not limited to a particular material, as various materials other than a lithium transition metal composite material are commonly offered.

The negative electrode sheet22has a negative electrode collector foil22a(here, a copper foil) of predetermined width and thickness, on each side of which a negative electrode active material layer22bcontaining a negative electrode active material is formed except for a blank portion22a1that is provided at a constant width at an edge on one side of the negative electrode collector foil22ain a width direction. For example, in a lithium-ion secondary battery, the negative electrode active material is a material such as natural graphite that can occlude lithium ions during charge and release the lithium ions, occluded during charge, during discharge. However, the negative electrode active material is not limited to a particular material, as various materials other than natural graphite are commonly offered.

For example, porous resin sheets that have required heat resistance and allow passage of an electrolyte are used as the separator sheets31,32. However, the separator sheets31,32are not limited to particular ones, as various separator sheets are offered.

Here, for example, the width of the negative electrode active material layer22bis larger than the width of the positive electrode active material layer21b. The width of the separator sheets31,32is larger than the width of the negative electrode active material layer22b. The blank portion21a1of the positive electrode collector foil21ais on one side of the battery case11, and the blank portion22a1of the negative electrode collector foil22ais on the opposite side of the battery case11, in the width direction. The positive electrode sheet21, the first separator sheet31, the negative electrode sheet22, and the second separator sheet32are wound together after being laminated in this order with their respective long sides directed in the same direction. The negative electrode active material layer22bcovers the positive electrode active material layer21bwith the separator sheets31,32interposed therebetween. The negative electrode active material layer22bis covered with the separator sheets31,32. The blank portion21a1of the positive electrode collector foil21aprotrudes from the separator sheets31,32on one side in the width direction. The blank portion22a1of the negative electrode collector foil22aprotrudes from the separator sheets31,32on the opposite side in the width direction.

In this embodiment, the battery case11has a flat rectangular housing space, and includes a case body11aand a lid11b. The case body11ahas a shape of a flat, substantially cuboid container, and one side of the case body11adefined by long sides and short sides is open. The lid11bis a plate-like member that has a shape matching the opening of the case body11aand is attached to the opening. The first terminal14and the second terminal15are mounted on each side of the lid11bin a longitudinal direction. As shown inFIG. 1, the electrode body16is flattened along a plane including an axis of winding so as to be housed inside the case body11aof the battery case11. The blank portion21a1of the positive electrode collector foil21ais disposed on one side and the blank portion22a1of the negative electrode collector foil22ais disposed on the opposite side along the axis of winding of the electrode body16. The blank portion21a1of the positive electrode collector foil21aand the blank portion22a1of the negative electrode collector foil22aare mounted on the second terminals15that are mounted respectively on both sides of the lid11bin the longitudinal direction. The electrode body16is housed inside the battery case11while thus mounted on the lid11b.

In this embodiment, as shown inFIG. 1, the first terminal14and the second terminal15are mounted on each side of the lid11bin the longitudinal direction. Here, the second terminal15has a base part15aand a mounting piece15b. The base part15ais mounted on the lid11bthrough the first insulating material12. The mounting piece15bextends from the base part15ainto the battery case11. The blank portion21a1of the positive electrode collector foil21aof the electrode body16is welded to the mounting piece15bof the second terminal15on the left side inFIG. 1. The blank portion22a1of the negative electrode collector foil22aof the electrode body16is welded to the mounting piece15bof the second terminal15on the right side inFIG. 1. On an outer side of the lid11b, a positive electrode connection terminal41is mounted on the first terminal14on the left side. Here, the outer side means the outer side of the battery case11. An inner side means the inner side of the battery case11. A negative electrode connection terminal42is mounted on the first terminal14on the right side. As shown inFIG. 2, a recess11b1recessed at a position corresponding to a part where the connection terminal42is mounted is provided in an outer surface of the lid11b.

FIG. 2shows a part of the lid11bwhere the first terminal14and the second terminal15on the negative electrode side are mounted, in a cross-section of the lid11bcut along a long-side direction at an intermediate position in a short-side direction. As shown inFIG. 2, the lid11bhas a mounting hole11cformed therein that is used to mount the first terminal14and the second terminal15. The mounting hole11c(seeFIG. 2) used to mount the first terminal14and the second terminal15is formed on each side of the lid11b.

The part where the first terminal14and the second terminal15on the positive electrode side are mounted has the same structure. Materials that can withstand potentials required respectively on the positive electrode side and the negative electrode side are used. Thus, for example, aluminum or an aluminum alloy is used for the first terminal14, the second terminal15, and the connection terminal41on the positive electrode side. For example, copper or a copper alloy is used for the first terminal14, the second terminal15, and the connection terminal42on the negative electrode side.

The insulating materials12,13are attached around the mounting hole11c. The first insulating material12is disposed on the inner side of the lid11band insulates the lid11band the second terminal15from each other. In this embodiment, the first insulating material12is formed by a resin member (in this embodiment, a fluorine-based resin) having required elasticity. The first insulating material12is also called a gasket, and keeps the mounting hole11csealed. In this embodiment, as shown inFIG. 2, the first insulating material12has a base part12a, a cylindrical part12b, and a reception part12c. The base part12ais a flat plat-like part attached to an inner surface of the lid11b. The cylindrical part12bis a part protruding from the base part12aand attached to an inner circumferential surface of the mounting hole11c. The cylindrical part12bhas an inside diameter according to the outside diameter of a shaft part15cprovided in the second terminal15(to be described later) so that the shaft part15ccan be inserted through the cylindrical part12b. The reception part12cis provided in a lower surface of the first insulating material12. The reception part12cis a part having a recess matching the shape of the base part15aof the second terminal15(to be described later) and used to position the base part15a.

The second insulating material13is a member that is disposed on the outer side of the lid11band insulates the lid11b, the first terminal14, and the connection terminal42from each another. The second insulating material13is formed by a resin member (in this embodiment, a polyamide-based resin), and is also called an insulator. In this embodiment, as shown inFIG. 2, a protrusion13ais provided on a lower surface of the second insulating material13so as to be attached in the recess11b1of the lid11b. A recess13bin which the negative electrode connection terminal42is disposed and a recess13cin which the first terminal14is attached are provided in an upper surface of the second insulating material13. The recess13cin which the first terminal14is attached has a through-hole13dformed therein at a position corresponding to the mounting hole11cformed in the lid11b. The through-hole13dhas an inside diameter according to the outside diameter of the shaft part15cprovided in the second terminal15(to be described later) so that the shaft part15ccan be inserted through the through-hole13d.

In this embodiment, the insulating materials12,13are composed of two members. The insulating materials12,13are members insulating the lid11b, the first terminals14, and the second terminals15from each other, and the materials, shapes, and the structures thereof are not limited to the above examples. The shape etc. of the mounting hole11cformed in the lid11bis not limited to those in the above structure, either. Thus, the insulating materials12,13may be composed of one member, or may be composed of two or more members.

The connection terminal42has a collar part42aand a shaft part42b. The collar part42ais positioned and attached in the recess13bprovided in the second insulating material13that is disposed on the outer side of the lid11b. Therefore, the collar part42aand the recess13bhave preferably matching shapes. The shaft part42bis a part which serves as an external output terminal, and on which, for example, a bus bar is mounted to form a battery pack.

As shown inFIG. 2, the first terminal14is placed on one side (in this embodiment, on the outer side) of the battery case11with the second insulating material13interposed therebetween.FIG. 3is a perspective view of the first terminal14. In this embodiment, the first terminal14is a member that is disposed on the second insulating material13disposed on the outer side of the lid11band retains the connection terminal42. As shown inFIG. 3, the first terminal14is a plate-like member disposed along the longitudinal direction of the lid11b. A step14ais provided at an intermediate part in a longitudinal direction of the first terminal14. An attachment hole14bin which the shaft part42bof the connection terminal42is attached is formed on one side of the step14a. On the opposite side of the step14a, an insertion hole14cthrough which the shaft part15cof the second terminal15(to be described later) is inserted is formed. The insertion hole14cis formed at a position that corresponds to the through-hole13dof the second insulating material13when the first terminal14is disposed on the second insulating material13.

An inclined surface14c1and a recess14c2are formed in the insertion hole14c. The inclined surface14c1is located in an inner circumferential surface of the first terminal14defining the insertion hole14c, and is formed at a rim on the outer side of the battery case11. Here, of the two rims of the inner circumferential surface of the first terminal14, a rim on the inner side of the battery case11corresponds to the first rim. Of the two rims of the inner circumferential surface of the first terminal14, the rim on the outer side of the battery case11corresponds to the second rim. The diameter of insertion hole14cat the inclined surface14c1increases gradually toward the outer side. The recess14c2is formed so as to open in the inclined surface14c1. The recess14c2has a bottom14c3at a position set back inside the first terminal14from the inclined surface14c1. In this embodiment, the inclined surface14c1and the recess14c2are located in the inner circumferential surface of the first terminal14defining the insertion hole14c, and extend continuously in a circumferential direction at the rim on the outer side of the battery case11. The recess14c2is formed so as to extend into the first terminal14from an intermediate part in a height direction of the inclined surface14c1. As a result, the recess14c2extends from the inclined surface14c1around the insertion hole14cinside the first terminal14, and as seen from above, a portion of the first terminal14overhangs the recess14c2.

The second terminal15is placed on the opposite side (in this embodiment, on the inner side) of the battery case11with the second insulating material13interposed therebetween. As shown inFIG. 1andFIG. 2, the second terminal15has the base part15a, the mounting piece15b, and the shaft part15c. Of these parts, the base part15ais mounted on the lid11bthrough the first insulating material12. As the mounting piece15bhas already been described, overlapping description will be omitted here.

The shaft part15cof the second terminal15is inserted through the mounting hole11cof the lid11band the insertion hole14c. In this embodiment, the cylindrical part12bof the first insulating material12is attached in the mounting hole11cof the lid11b. The shaft part15cof the second terminal15is inserted through the inside of the cylindrical part12b. The shaft part15cof the second terminal15is further inserted through the through-hole13dof the second insulating material13and the insertion hole14cof the first terminal14disposed on the second insulating material13.

A leading end15c1of the shaft part15cis crushed and riveted around the insertion hole14con the outer side of the first terminal14. At least a portion of the shaft part15creaches into the recess14c2formed in the inclined surface14c1of the first terminal14.

Here,FIG. 4is a sectional view taken along the line IV-IV ofFIG. 2, and is a lateral sectional view of the lid11bin the width direction showing a part where the first terminal14and the second terminal15are joined together.

As shown inFIG. 4, in the part where the first terminal14and the second terminal15are joined together, the second terminal15acts like a rivet. Specifically, the shaft part15cof the second terminal15is inserted through the cylindrical part12bof the first insulating material12attached in the mounting hole11cof the lid11b, the through-hole13dof the second insulating material13, and the insertion hole14cof the first terminal14. The leading end15c1of the shaft part15cis crushed and riveted around the insertion hole14cof the first terminal14. As a result, the second terminal15is fixed while holding the first insulating material12, the lid11b, the second insulating material13, and the first terminal14between the base part15aand the leading end15c1of the shaft part15c. Moreover, at least a portion of the shaft part15creaches into the recess14c2formed in the inclined surface14c1of the first terminal14. The recess14c2is open in the inclined surface14c1and extends from the inclined surface14c1into the first terminal14. Thus, with a portion of the shaft part15cof the second terminal15reaching into the recess14c2, this structure does not allow the first terminal14and the second terminal15to easily come apart.

In particular, a portion of the shaft part15cof the second terminal15reaches into the recess14c2that is open in the inclined surface14c1and recessed inside the first terminal14from the inclined surface14c1, so that required joint strength can be secured without the leading end of the shaft part15cbeing welded to the first terminal14. For example, the joint strength to withstand vibration and shock accompanied by acceleration in an ultralow temperature environment that can arise in frigid regions can be provided. Again, a portion of the shaft part15cof the second terminal15reaches into the recess14c2that is open in the inclined surface14c1and recessed inside the first terminal14from the inclined surface14c1. The shaft part15cof the second terminal15is deformed so as to reach into the recess14c2in the inclined surface14c1. In this process, an oxide film on a surface of the shaft part15cis torn and a new surface is revealed, and thus condensation of a surface oxide film at the joint part is reduced. As a result, resistance at the joint part of the first terminal14and the second terminal15decreases.

In this embodiment, as described above, the first terminal14having the insertion hole14c, the inclined surface14c1, and the recess14c2is disposed on the outer side of the battery case11, and the second terminal15having the shaft part15cis disposed on the inner side of the battery case11. In the sealed battery proposed herein, a terminal having parts corresponding to the insertion hole14c, the inclined surface14c1, and the recess14c2may be disposed on the inner side of the battery case11, while a terminal having a part corresponding to the shaft part15cmay be disposed on the outer side of the battery case11.

For example, parts corresponding to the insertion hole14c, the inclined surface14c1, and the recess14c2of the first terminal14may be provided in the terminal disposed on the inner side of the battery case11. In this case, a part corresponding to the shaft part15cof the second terminal15may be provided in the terminal disposed on the outer side of the battery case11. The part corresponding to the shaft part15cprovided in the terminal disposed on the outer side of the battery case11may be inserted through the insertion hole14cprovided in the other terminal disposed on the inner side of the battery case11. Then, the leading end of the shaft part15cmay be crushed and riveted around the insertion hole14cof the other terminal. As a result, a portion of the part corresponding to the shaft part15cshould be deformed and reach into the part corresponding to the recess14c2. Thus, the first terminal14is not limited to a so-called external terminal that is disposed on the outer side of the battery case11. The second terminal15is not limited to a so-called internal terminal that is disposed on the inner side of the battery case11. In short, the joint structure of the terminals disposed on the inner side and the outer side of the battery case11may have those terminals on the opposite sides of the battery case11from those in the embodiment shown inFIG. 2andFIG. 4.

The first terminal14and the second terminal15may be made of different materials. For example, in a secondary battery having such a charge potential that an open circuit voltage between the positive electrode and the negative electrode is about 4V, aluminum or an aluminum alloy is used as the positive electrode-side electrode terminal so as to withstand the required potential. In some cases, different materials are used for the first terminal14and the second terminal15. For example, in the embodiment shown inFIG. 2andFIG. 4, aluminum (e.g., aluminum with purity 99.50% or higher (A1050)) that is a soft material is preferably used for the second terminal15of the positive electrode having the shaft part15cto be crushed. On the other hand, for example, an aluminum alloy having excellent corrosion resistance and strength (e.g., A5052) is preferably used for the first terminal14. In the case where different materials are thus used for the first terminal14and the second terminal15, the first terminal14and the second terminal15undergo thermal expansion differently in an ultralow temperature environment. According to the above embodiment, even in such a case, the joined first terminal14and second terminal15do not easily come apart as at least a portion of the shaft part15cof the second terminal15reaches into the recess14c2formed in the inclined surface14c1of the first terminal14.

From this perspective, the width of the recess14c2opening in the inclined surface14c1is preferably, for example, within a range from 0.1 mm to 0.3 mm (e.g., 0.2 mm). Here, the width of the recess14c2is defined by the width of the recess14c2opening along the inclined surface14c1in an axial direction of the insertion hole14c.

The depth of the recess14c2is within a range from 0.3 mm to 0.7 mm (e.g., from 0.4 mm to 0.6 mm). Here, the depth of the recess14c2can be defined by the distance from the inclined surface14c1to a deepest point in the recess14c2.

For example, such a recess14c2can be formed by press molding or electric discharge machining. However, the method of forming the recess14c2is not limited to these examples, and various other methods can be used. In this embodiment, the recess14c2is formed in the inclined surface14c1continuously in the circumferential direction. However, unlike in this embodiment, the recess14c2may be formed in the inclined surface14c1intermittently in the circumferential direction. For example, four recesses14c2may be formed at 90-degree intervals in the circumferential direction. Alternatively, three, six, or eight recesses14c2may be formed at 120-, 60-, or 45-degree intervals, respectively,

Next, a manufacturing method of a sealed battery having such a joint structure of the first terminal14and the second terminal15will be described. Here,FIG. 5toFIG. 7are sectional views illustrating steps in the sealed battery manufacturing method.

In this sealed battery manufacturing method, the battery case11having the mounting hole11c, the metal first terminal14having the insertion hole14ccorresponding to the mounting hole11c, the metal second terminal15having the shaft part15cthat is insertable through the mounting hole11cand the insertion hole14c, and one or more insulating materials (in this embodiment, the first insulating material12and the second insulating material13) are prepared.

Next, as shown inFIG. 6, the first terminal14is placed on one side of the battery case11(in the embodiment shown inFIG. 5, on the outer side of the battery case11) with the second insulating material13interposed therebetween and with the mounting hole11cand the insertion hole14caligned with each other.

Next, the second terminal15is placed on the opposite side of the battery case11(in the embodiment shown inFIG. 5, on the inner side of the battery case11) with the first insulating material12interposed therebetween and with the shaft part15cinserted through the mounting hole11cand the insertion hole14c.

Next, the leading end of the shaft part15cis crushed and riveted around the insertion hole14con the outer side of the first terminal14.

Here, at the rim on the outer side of the battery case11, the inner circumferential surface of the prepared first terminal14defining the insertion hole14chas the inclined surface14c1of which the diameter increases gradually toward the outer side and the recess14c2that is open in the inclined surface14c1. The recess14c2has the bottom14c3at a position set back inside the first terminal14from the inclined surface14c1. Then, in the step of crushing the leading end of the shaft part15cand riveting the leading end around the insertion hole14c, a portion of the shaft part15creaches into the recess14c2formed in the inclined surface14c1of the first terminal14. Thus, the sealed battery10can be provided in which the first terminals14and the second terminals15do not easily come apart.

FIG. 5shows a state where the members have been assembled. As shown inFIG. 5, in this embodiment, the leading end of the shaft part15cof the second terminal15to be prepared has preferably a cylindrical shape. As shown inFIG. 5, the first insulating material12and the second insulating material13are placed on the lid11b, and the first terminal14and the second terminal15are mounted on these insulating materials. In this process, the protrusion13aof the second insulating material13is attached in the recess11b1of the lid11b, and the mounting hole11cof the lid11band the through-hole13dof the second insulating material13are aligned with each other. Next, the collar part42aof the connection terminal42is mounted in the recess13bof the second insulating material13(seeFIG. 2). Then, the first terminal14is mounted on the second insulating material13with the attachment hole14bof the first terminal14attached to the shaft part42bof the connection terminal42. In this process, the through-hole13dof the second insulating material13and the insertion hole14cof the first terminal14are aligned with each other. Next, the first insulating material12is attached on the inner side of the lid11b. The cylindrical part12bof the first insulating material12is attached in the mounting hole11cof the lid11b. In this embodiment, a projection11c1is provided at a rim of the mounting hole11con the inner side of the lid11b. The second terminal15is mounted with the shaft part15cof the second terminal15inserted through the cylindrical part12bof the first insulating material12.

Next, as shown inFIG. 6, the first terminal14and the second terminal15are held between a pair of pressing parts61,62of a pressing device, and the first insulating material12and the second insulating material13are combined so that the lid11b, the first terminal14, and the second terminal15come in close contact with each other. In this embodiment, the projection11c1is provided at the rim defining the mounting hole11cof the lid11b, and the projection11c1digs into the first insulating material12(gasket) on the inner side of the lid11b. Thus, the lid11bis kept sealed around the mounting hole11c.

In this embodiment, the leading end15c1of the shaft part15chas a cylindrical shape. As shown inFIG. 7, a rotating member60is pressed against the cylindrical leading end15c1of the shaft part15cwhile being moved along the leading end15c1in a circumferential direction. The rotating member60crushes the cylindrical leading end15c1of the shaft part15csequentially in the circumferential direction. InFIG. 7, a one-dot dashed line A indicates an axis of rotation of the rotating member60, and a one-dot dashed line B indicates an axis of revolution of the rotating member60. In this embodiment, the rotating member60is pressed against the leading end15c1of the cylindrical shaft part15cwhile revolving around the axis of revolution that is provided along a central axis of the shaft part15c. The step of pressing the rotating member60against the leading end15c1is preferably performed in a state where the first terminal14and the second terminal15are held between the pair of pressing parts61,62of the pressing device. A portion of the shaft part15cis plastically deformed and introduced into the recess14c2opening in the inclined surface14c1. In the step of riveting the first terminal14and the second terminal15, at least a portion of the shaft part15cshould reach into the recess14c2formed in the inclined surface14c1of the first terminal14. Therefore, the processing method is not limited to the one described above.

Thus, in the sealed battery10proposed herein, the first terminal14is placed on one side of the lid11bof the battery case11with the second insulating material13interposed therebetween as shown inFIG. 2. The first terminal14has: the insertion hole14cthat is formed at a position corresponding to the mounting hole11cof the lid11b; the inclined surface14c1that is located in the inner circumferential surface of the first terminal14defining the insertion hole14c, is formed at the rim on the outer side of the battery case11, and has a diameter increasing gradually toward the outer side; and the recess14c2that is open in the inclined surface14c1. The recess14c2has the bottom at a position set back inside the first terminal14from the inclined surface14c1. The second terminal15is placed on the opposite side of the lid11bwith the first insulating material12interposed therebetween. The second terminal15has the shaft part15cinserted through the mounting hole11cand the insertion hole14c. The leading end of the shaft part15cis crushed and riveted around the insertion hole14con the outer side of the first terminal14. At least a portion of the shaft part15creaches into the recess14c2formed in the inclined surface14c1of the first terminal14. Thus, for example, the required joint strength to withstand vibration and shock can be provided without welding. Alternatively, a portion of the riveted shaft part15cmay be combined with the first terminal14by welding.

While the sealed battery and the sealed battery manufacturing method proposed herein have been described from various aspects, unless otherwise mentioned, the present disclosure is not limited by the embodiment and the examples presented herein.