JP2009289589A - Battery's complex lid, sealed battery using the same, and method of manufacturing battery's complex lid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery's complex lid that is not affected by swage dimension of a terminal and has excellent adherence between the terminal and a gasket. <P>SOLUTION: The battery's complex lid comprises a lid having an opening, and a terminal disposed to the opening of the lid via the gasket. The terminal comprises: an external terminal exposed to the top surface side of the lid; a hollow axis portion that fits into a hole of the external terminal and a hole of the gasket, and presses the gasket in a direction perpendicular to the axial direction; a head portion that is exposed to the top surface side of the lid from the hole of the external terminal in the upper portion of the hollow axis portion and is swaged; and an internal terminal that is formed to extend towards the outside from the bottom of the hollow axis portion and has a flange that is exposed to the bottom surface side of the lid. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sealed battery, and more particularly to a battery composite lid used for a sealed battery and a method for manufacturing the same.

Conventionally, nickel cadmium batteries and nickel hydride storage batteries have been used as power sources for electronic devices such as AV devices, personal computers, and portable communication devices. In recent years, with the improvement in performance of electronic devices, demand for non-aqueous electrolyte secondary batteries represented by lithium ion secondary batteries that can be rapidly charged, has high energy density, and is excellent in safety has increased. ing.
Among non-aqueous electrolyte secondary batteries, there is an expectation to improve the performance of square non-aqueous electrolyte secondary batteries with high energy density, excellent load characteristics, and high space efficiency suitable for thinning electronic devices. It is growing.

  In a rectangular nonaqueous electrolyte secondary battery, the tab attached to the electrode of the power generation element is connected to an internal terminal exposed inside the battery, and is electrically connected to the outside of the battery by an external terminal connected to the internal terminal and exposed outside the battery. Is taken out. When using a metal battery case, the tab connected to the electrode having the same polarity as the battery case is directly connected to the battery case or connected to a metal lid joined to the battery case. The tab connected to the electrode having a polarity different from that of the battery case is connected to the internal terminal. A gasket is provided between the internal terminal and the battery case or metal lid to ensure airtightness, and the internal terminal is electrically insulated from the battery case or metal lid by the gasket. .

As a conventional battery, for example, a sealed battery using a lid provided with a hollow rivet as an internal terminal and an external terminal has been proposed (for example, Patent Document 1). Hereinafter, the structure of the lid in this battery will be described with reference to FIG. FIG. 4 is a longitudinal sectional view of a main part of a lid in a conventional battery sealed type.
As shown in FIG. 4, an internal terminal 108 and a hollow rivet 109 are attached to the opening of the lid 104 via an upper gasket 111 and a lower gasket 110. The hollow rivet 109 includes a flange exposed on the upper surface side of the lid 104, a hollow portion of a cylindrical portion in the upper gasket 111 disposed in the opening of the lid 105, and a lower gasket 110 disposed on the lower surface of the lid. And a hollow shaft portion inserted into the hole of the internal terminal 108 disposed on the lower surface of the lower gasket, and a caulking portion exposed on the internal terminal 108.

  Hereinafter, a method for manufacturing the lid will be described. The upper gasket 111 is disposed on the lid 104 so as to cover the stepped portion and the opening provided around the opening on the upper surface side of the lid 104. The flange portion of the hollow rivet 109 is disposed on the step portion via the upper gasket 111, and the upper portion of the hollow shaft portion of the hollow rivet 109 is inserted into the hollow portion of the cylindrical portion of the upper gasket 111. The lower part of the hollow shaft portion of the hollow rivet 109 is inserted into the holes of the lower gasket 110 and the internal terminal 108. In this state, the lower end portion of the hollow shaft portion of the hollow rivet 109 is bent outward and crimped around the opening of the internal terminal 108. The edge of the caulking portion of the hollow rivet 109 is welded to the internal terminal to form a welded portion 121. In this manner, the hollow rivet 109 is caulked to the internal terminal 108, and the hollow rivet 109 is brought into close contact with the upper gasket 111 and the lower gasket 110, thereby ensuring the hermeticity of the battery.

  As another conventional battery, a sealed battery using a lid body having a solid rivet as an internal terminal has been proposed (for example, Patent Document 1). Hereinafter, the structure of the lid in this battery will be described with reference to FIG. FIG. 5 is a longitudinal sectional view of a main part of a lid in another conventional sealed battery. As shown in FIG. 5, a solid rivet 208 and an external terminal 209 are attached to the opening of the lid 204 via an upper gasket 211 and a lower gasket 210. The hollow rivet 208 is inserted through the upper gasket 211, the lower gasket 210, and the external terminal 209 into the caulked portion 208 a exposed from the hole of the external terminal 209 disposed on the upper surface side of the lid, and the opening of the lid 204. And a flange portion 208c disposed on the lower surface side of the lid 204 via a lower gasket.

Hereinafter, a method for manufacturing the lid will be described. The lower gasket 210 is disposed around the opening on the inner surface side of the lid 204 and on the inner surface of the opening, and the shaft 208b of the solid rivet 208 is inserted into the hole of the lower gasket 210 from below. At this time, the flange portion 208 c of the central shaft rivet 208 is disposed on the lower surface of the lid body 204 via the lower gasket 210. The upper gasket 211 and the external terminal 209 are inserted into the upper portion of the shaft portion 208b of the solid rivet 208. The tip end portion of the shaft portion 208b of the solid rivet 208 is caulked. In this way, the solid rivet 208 is caulked to the external terminal 209, and the hollow rivet 208 is brought into close contact with the upper gasket 211 and the lower gasket 210, thereby ensuring the hermeticity of the battery.
JP 2002-324541 A

  However, the conventional sealed battery is sealed by compressing the gasket in the height direction (the thickness direction of the lid). When the caulking dimension changes, the compression ratio of the gasket changes, and therefore the caulking dimension greatly affects the sealing performance. For this reason, a high-precision caulking technique for minimizing the variation in caulking dimensions is required, and it has been difficult to increase productivity.

  Accordingly, an object of the present invention is to provide a battery composite lid having excellent adhesion between a terminal portion and a gasket regardless of the crimping size of the terminal portion in order to solve the above-described conventional problems. It is another object of the present invention to provide a method for producing a battery composite lid that can easily and reliably obtain the battery composite lid. It is another object of the present invention to provide a highly reliable sealed battery having excellent sealing properties.

The present invention is a battery composite lid comprising a lid having an opening, and a terminal portion disposed via a gasket in the opening of the lid,
The terminal portion is an external terminal exposed on the upper surface side of the lid,
A head portion that is exposed and caulked from the hole of the external terminal, a hollow shaft portion that fits into the hole of the external terminal and the hole of the gasket, and is formed to extend outward from a lower end portion of the hollow shaft portion; An internal terminal having a flange exposed on the lower surface side of the lid,
It is characterized by comprising.

The present invention also relates to a sealed battery using the battery composite lid.
The battery is
A power generation element comprising an electrode group in which a belt-like positive electrode and a belt-like negative electrode are wound with a belt-like separator interposed therebetween,
A battery case having an opening and storing the power generation element;
The battery composite lid for sealing the opening of the battery case;
A negative electrode tab drawn from the negative electrode;
A positive electrode tab drawn from the positive electrode;
Comprising
The negative electrode tab is connected to the flange;
The positive electrode tab is preferably connected to the lower surface of the lid.
It is preferable that the lid body has a liquid inlet and a stopper is attached to the liquid inlet.

Furthermore, the present invention is a method for producing the above battery composite lid,
(1) the step of disposing the external terminal and the internal terminal through the gasket in the opening of the lid, and inserting the hollow shaft portion of the internal terminal into the hole of the external terminal and the gasket; ,
After the step (1), a caulking punch is inserted into the hollow portion of the hollow shaft portion to spread the hollow shaft portion in a direction perpendicular to the axial direction, while pressing the gasket in a direction perpendicular to the axial direction. Caulking the head exposed from the hole of the external terminal (2);
It is characterized by including.

  According to the present invention, in a battery composite lid having a lid having an opening and a terminal portion fitted to the opening of the lid via a gasket, the terminal portion is a lateral direction (direction in which the gasket is crimped) Since it is pressed in the vertical direction), a battery composite lid having excellent adhesion (airtightness) between the terminal portion and the gasket can be provided without being affected by fluctuations in the caulking dimensions of the terminal portion.

Moreover, the manufacturing method of the battery composite cover which can obtain the said battery composite cover easily and reliably can be provided. Since the compression of the gasket is determined by the punch diameter inserted into the hollow shaft during caulking, stable adhesion between the gasket and the terminal can be obtained without being affected by the caulking dimensions, and the battery is sealed. Improves.
Furthermore, by using the battery composite lid, it is possible to provide a highly reliable sealed battery excellent in sealing performance.

The present invention relates to a lid having an opening, and a battery composite lid having a terminal portion fitted to the opening of the lid through a gasket.
And the said terminal part, The external terminal exposed to the upper surface side of the said cover body,
A hollow shaft portion that fits into the hole of the external terminal and the hole of the gasket and presses the gasket in a direction perpendicular to the axial direction, and the upper surface side of the lid body from the hole of the external terminal at the upper portion of the hollow shaft portion And a head that is caulked to be exposed, and an internal terminal that is formed to extend outward from the lower portion of the hollow shaft portion and is exposed on the lower surface side of the lid body. .
By caulking the internal terminal to the external terminal and compressing the gasket in the axial direction of the hollow shaft portion (thickness direction of the lid) due to caulking, by compressing the gasket in the direction perpendicular to the axial direction by the hollow shaft portion, A battery composite lid excellent in hermeticity can be obtained. As described above, since the gasket is sufficiently compressed in the direction perpendicular to the axial direction, good adhesion to the gasket of the terminal portion can be ensured regardless of the caulking dimension.

The present invention also relates to a method for manufacturing the battery composite lid,
(1) the step of disposing the external terminal and the internal terminal through the gasket in the opening of the lid, and inserting the hollow shaft portion of the internal terminal into the hole of the external terminal and the gasket; ,
After the step (1), a caulking punch is inserted into the hollow portion of the hollow shaft portion to spread the hollow shaft portion in a direction perpendicular to the axial direction, while pressing the gasket in a direction perpendicular to the axial direction. Caulking the head exposed from the hole of the external terminal (2);
It has the feature in the point containing.

Thereby, the said battery composite cover is obtained easily and reliably. The force for compressing the gasket in the direction perpendicular to the axial direction of the hollow shaft portion (the direction perpendicular to the direction compressed by the crimping of the terminal portion) can be easily adjusted by changing the diameter of the crimping punch. Thus, since compression of a gasket is determined by the punch diameter inserted in a hollow shaft part at the time of a caulking process, the outstanding adhesiveness of a gasket and a terminal part is obtained, without being influenced by the caulking dimension.
Furthermore, the present invention relates to a sealed battery using the battery composite lid. One of the positive electrode and the negative electrode in the sealed battery is electrically connected to the lid (or battery case) of the battery composite lid, and the other of the positive electrode and the negative electrode is electrically connected to the buttocks of the battery composite lid. Connected. By using the battery composite lid of the present invention, a battery having excellent sealing properties can be obtained reliably.

Hereinafter, the structure of a prismatic lithium ion secondary battery as an embodiment of the sealed battery of the present invention will be described with reference to FIGS. FIG. 1 is a schematic longitudinal sectional view of a lithium ion secondary battery which is an embodiment of the battery of the present invention. FIG. 2 is a schematic longitudinal sectional view in a direction perpendicular to FIG. FIG. 3 is a longitudinal sectional view of a main part showing the vicinity of the terminal portion of the battery composite lid in the lithium ion secondary battery of FIG.
Inside the battery case 1 made of an aluminum alloy outer can having a bottomed rectangular tube shape having an opening, a power generation element 2 made of a positive electrode, a negative electrode, and a separator disposed between the two electrodes is housed. The battery case 1 also serves as a positive electrode terminal. In addition, when a battery case serves as a negative electrode terminal, a nickel plating steel plate is used for a battery case, for example. The opening of the battery case 1 is sealed with the battery composite lid 15 of the present invention.

Here, FIG. 3 shows a longitudinal sectional view of the main part of the battery composite lid 15 of FIG. As shown in FIG. 3, the battery composite lid 15 is made of a square plate-like metal (for example, made of aluminum) having a cylindrical opening 4 a that penetrates from the upper surface side (battery outer side) to the lower surface side (battery inner side). ) It is composed of a lid 4 and a metal terminal portion disposed in the opening 4a of the lid 4 via a gasket. The opening 4a of the lid 4 is sealed by the terminal portion and the gasket.
The terminal portion is electrically exposed to the external terminal 9 exposed on the upper surface side (battery external side) of the lid body 4 and the external terminal 9 and is exposed to the lower surface side (battery internal side) of the lid body 4. Consists of. The external terminal 9 is disposed on a step 4 b provided around the opening 4 a on the upper surface side of the lid 4.
The internal terminal 8 is an eccentric hollow rivet, and is inserted into the hole of the external terminal 9 and the hole of the gasket (the opening of the upper gasket 11 described later and the hollow part of the hollow cylindrical portion of the lower gasket 10), and the gasket is axially A hollow cylindrical hollow shaft portion 8b that is pressed in a direction perpendicular to the caulking direction, and an upper portion of the hollow shaft portion 8b that is disposed so as to cover the hollow portion of the hollow shaft portion 8b. A head 8a that is exposed on the upper surface side of the body 4 and that is caulked by an inclined portion 9a provided around the hole of the external terminal 9, and a shaft that is on the outer side (opposite to the hollow portion) from the lower end portion of the hollow shaft portion 8b. It is formed to extend along a direction perpendicular to the direction, and includes a square plate-shaped flange portion 8 c exposed on the lower surface side of the lid 4. One end of the hollow portion of the hollow shaft portion 8b is closed by being covered with the head portion 8a, and the other end (end portion on the flange portion 8c side) is opened.

The hollow shaft portion 8b is provided so that the shaft is perpendicular to the plate-shaped flange portion 8c, with the position deviated from the center of the flange portion 8c (the eccentric position) as a base point. The hollow shaft portion 8b is preferably provided at a position that is 1/4 to 5/6 away from the center of the flange portion 8c with respect to the distance from the center of the flange portion 8c to the end in the longitudinal direction. More preferably, it is 1/3 to 4/5.
With the above configuration, the position where the hollow shaft portion faces the gasket (upper gasket and lower gasket) is relatively separated from the welded portion with the negative electrode tab of the flange portion. It is hardly affected by the heat generated when welding to the lower surface.
The hollow shaft portion 8b is provided at a position off the center of the flange portion 8c, but the hollow shaft portion may be provided at the center of the flange portion.

The gasket includes an upper gasket 11 and a lower gasket 10. The upper gasket 11 covers the step 4b provided around the opening 4a on the upper surface side of the lid 4 and has an opening for inserting the hollow shaft 8b. The lower gasket 10 covers the inner surface of the opening 4a of the lid 4 and is formed so as to extend outward from the hollow cylindrical portion for inserting the hollow shaft portion 8b and the lower end of the hollow cylindrical portion. It has a collar part for covering the lower surface. The external terminal 9 is electrically insulated from the lid 4 by the upper gasket 11. The internal terminal 8 is electrically insulated from the lid 4 by the upper gasket 11 and the lower gasket 10.
The hole of the external terminal 9, the opening of the upper gasket 11, and the hollow portion of the cylindrical portion of the lower gasket 10 have the same diameter so that the hollow shaft portion 8b of the internal terminal 8 can be inserted. It is provided on the same axis. The hole of the external terminal 9, the opening of the upper gasket 11, and the hollow portion of the cylindrical portion of the lower gasket 10 communicate with each other to form one columnar hole. The hollow shaft portion 8b is inserted into this hole portion.

  As a result, the upper gasket 11 is pressed outward (inner side of the opening of the lid) from the inner surface of the opening. The lower gasket 10 is pressed outward (inner side of the opening of the lid) from the inner surface of the hollow cylindrical portion. Thus, the gasket is compressed in a direction perpendicular to the direction compressed by the caulking of the terminal portion. Therefore, stable adhesion between the terminal portion and the gasket can be obtained without being affected by the caulking dimensions, and a battery having excellent sealing properties can be reliably obtained.

Hereinafter, the manufacturing method of said battery composite cover 15 is demonstrated.
After the lower gasket 10 is disposed in the opening 4a of the lid 4 so that the hollow cylindrical portion of the lower gasket 10 is fitted in the opening 4a of the lid 4, the hollow shaft portion 8b of the internal terminal 8 is lowered from below. The gasket 10 is inserted into the hollow part of the hollow cylindrical part. The external terminal 9 is arranged on the step 4b of the lid body 4 via the upper gasket 11, and the hollow shaft portion 8b is inserted into the hole of the external terminal 9 and the opening of the upper gasket 11 (step (1)).
A cylindrical caulking punch is inserted into the hollow portion of the hollow shaft portion 8b from the opening on the flange portion 8c side in the hollow portion of the hollow shaft portion 8b so that the hollow shaft portion 8b is in a direction perpendicular to the axial direction (on the opposite side to the hollow portion side). ) In the direction of. In this way, the head exposed from the hole of the external terminal 9 while pressing the upper gasket 11 and the lower gasket 10 in contact with the hollow shaft portion 8b in the direction perpendicular to the axial direction (the direction opposite to the hollow portion side). The head 8a is pushed and crimped so that the portion 8a is along the inclined portion 9a provided around the hole of the external terminal 9 (step (2)).
In addition, when the caulking punch is inserted, a caulking die having a recess corresponding to the head (a jig corresponding to the punch) is used to press the recess against the head 8a, thereby increasing the diameter of the head 8a. It is desirable. Thereby, the fastening strength of components (terminal part) becomes high and reliability improves.

By the above method, the hollow shaft portion is pushed in a direction perpendicular to the axial direction, and at the same time, the internal terminal can be caulked to the external terminal, so that the process can be simplified and the productivity is improved.
In the above step (2), by changing the size of the diameter of the caulking punch, the inner diameter and outer diameter of the hollow shaft portion of the internal terminal, the diameter of the opening portion of the upper gasket, and the diameter of the hollow portion of the hollow cylindrical portion of the lower gasket The pressing force in the direction perpendicular to the axial direction of the gasket can be easily controlled.
The outer diameter of the hollow shaft portion before the caulking punch is inserted is 0.02 to the hole diameter of the gasket before the caulking punch is inserted (the diameter of the opening of the upper gasket 11 and the diameter of the hollow portion of the hollow cylindrical portion of the lower gasket 10). Preferably it is smaller by 0.2 mm. In the step (2), the hollow shaft portion can be smoothly inserted into the hole of the gasket.
The outer diameter of the hollow shaft portion 8b after the caulking punch is inserted is preferably larger by 0.05 to 0.5 mm than the hole diameter of the gasket (upper gasket 11 and lower gasket 10) before the caulking punch is inserted. At this time, the gasket can be sufficiently pressed outward.
The diameter of the caulking punch is preferably larger by 0.05 to 0.5 mm than the inner diameter of the hollow shaft portion 8b before the caulking punch is inserted.
In step (2), the pressure that pushes the gasket in a direction perpendicular to the axis (force that spreads outward), that is, the force that pushes the upper gasket 11 from the inner surface of the opening to the outer side (the inner surface of the opening of the lid) In the gasket 10, it is preferable to set the force that presses the outer side (the inner side of the opening of the lid) from the inner surface of the hollow cylindrical portion to a pressure that can stably obtain the desired dimension.

The diameter of the caulking punch is, for example, 1.8 mm. At this time, the inner diameter of the hollow shaft portion 8b before the caulking punch is inserted is, for example, 1.3 to 1.75 mm.
The hole diameter of the gasket (the diameter of the opening portion of the upper gasket 11 and the inner diameter of the hollow cylindrical portion of the lower gasket 10) before the hollow shaft portion 8b is inserted into the hole of the gasket is, for example, the thickness of the gasket (the hollow shaft portion 8b). When the thickness of the lower gasket 10 in the direction perpendicular to the axial direction is 0.3 mm, it is 1.6 to 2.05 mm.
The outer diameter of the hollow shaft portion 8b after the caulking punch is inserted is, for example, 1.65 to 2.55 mm.

  The lid 4 has a safety valve 6 made of a thin part. When the gas pressure in the battery rises significantly, the gas in the battery is released to the outside by breaking the safety valve 6 by the gas pressure. The safety valve 6 may be a conventionally known one. The clad plate type or the stamp type is preferable because it is inexpensive and can be installed even if the lid 4 is thin.

A welded portion 5 is formed by laser welding at a joint portion between the battery case 1 and the lid 4.
A positive electrode tab 7 drawn from the positive electrode of the power generation element 2 is connected to the lower surface of the lid 4. For the positive electrode tab 7, for example, an aluminum lead is used.
The negative electrode tab 12 drawn out from the negative electrode of the power generation element 2 is connected to the flange portion of the internal terminal 8 through the gap 20 of the upper insulating plate 3. For the negative electrode tab, for example, a nickel lead or a copper lead is used. The upper gasket 3 and the upper insulating plate 3 having a U-shaped cross section are arranged so as to isolate the negative electrode tab 12 from the lid 4 and the power generation element 2.

  As a material for the internal terminal 8 and the external terminal 9, it is preferable to use stainless steel, iron whose surface is nickel-plated, copper, or a copper alloy in order to ensure a good electrical contact state between the two terminals. From the viewpoint of formability, it is preferable to use copper or a copper alloy. Also, it is preferable to use the above material from the viewpoint of welding the external terminal and the external lead mainly made of nickel and welding the internal terminal and the negative electrode tab.

In order to prevent leakage of the non-aqueous electrolyte due to the influence of heat when laser welding the joint between the battery case 1 and the lid 4, it is preferable to use a fluororesin having a high heat resistance temperature for the upper gasket 11. For the same reason as the upper gasket 11, the lower gasket 10 is preferably made of a fluororesin having a high heat resistance temperature.
For the upper gasket 11 and the lower gasket 10, for example, a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer is used. In this case, the gasket compression rate when the hollow shaft portion is inserted is preferably 10 to 70%, more preferably 20 to 50%.
Further, depending on the size and shape of the battery, a resin such as polypropylene (PP) and polyphenylene sulfide (PPS) may be used for the upper gasket 11 and the lower gasket 10, and depending on the material, the hollow shaft portion may be inserted. What is necessary is just to set a gasket compression rate suitably.

  The lid 4 has a liquid injection hole 13 for injecting a non-aqueous electrolyte into the battery case 1 during battery manufacture. The liquid injection hole 13 is closed with an aluminum plate and a plug 14 made of a rubber plug that is in close contact with the lower surface of the aluminum plate. The plug body 14 is fixed in the liquid injection hole 13 by placing the peripheral edge portion of the aluminum plate of the plug body 14 on a step provided around the liquid injection hole 13 and laser welding.

  The power generation element 2 is configured by winding a belt-like positive electrode and a belt-like negative electrode in a flat shape through a belt-like separator. Hereinafter, a procedure for inserting the power generation element 2 into the battery case 1 will be described. The positive electrode plate and the negative electrode plate are wound in a non-circular shape through a separator. The wound body is deformed into a flat shape by press molding so as to correspond to the rectangular battery case 1. The power generating element 2 is inserted into the battery case so that the winding shaft is perpendicular to the bottom surface of the battery case 1.

  An insulating tape (not shown) is disposed between the bottom of the power generation element 2 and the inner bottom surface of the battery case 1, and the bottom of the power generation element 2 is electrically insulated from the inner bottom surface of the battery case 1. In addition, an upper insulating plate 3 is disposed on the power generation element 2 in order to ensure an electrical insulation state between the power generation element 2 and a component positioned above the power generation element 2.

The positive electrode includes, for example, a positive electrode current collector and a positive electrode mixture layer formed on the positive electrode current collector. The positive electrode mixture layer includes, for example, a positive electrode active material, a conductive material, and a binder.
What is necessary is just to produce a positive electrode by a conventionally well-known method. Specifically, a positive electrode active material, a conductive material, and a binder are dispersed in a solvent to obtain a positive electrode paste. A positive electrode paste is applied to both surfaces of a positive electrode current collector made of aluminum foil, and then dried to form a positive electrode mixture layer on both surfaces of the positive electrode current collector to obtain a positive electrode. The obtained positive electrode is rolled to a predetermined thickness.
Conventionally known materials may be used for the positive electrode active material, the conductive material, the binder, and the solvent. Lithium cobaltate (LiCoO ₂ ) as a positive electrode active material, acetylene black as a conductive material, polyvinylidene fluoride (PVDF) or a copolymer thereof as a binder, and N-methyl-2-pyrrolidone (NMP) as a solvent Is preferred.

The negative electrode includes, for example, a negative electrode current collector and a negative electrode mixture layer formed on the negative electrode current collector. The negative electrode mixture layer includes, for example, a negative electrode active material, a conductive material, and a binder.
What is necessary is just to produce a negative electrode by a conventionally well-known method. Specifically, a negative electrode active material, a conductive material, and a binder are dispersed in a solvent to obtain a negative electrode paste. After apply | coating a negative electrode paste on both surfaces of the negative electrode collector which consists of copper foil, it dries and forms a negative mix layer on both surfaces of a negative electrode collector, and obtains a negative electrode. The obtained negative electrode is rolled to a predetermined thickness.
Conventionally known materials may be used for the negative electrode active material, the conductive material, the binder, and the solvent. It is preferable to use a carbon material such as graphite as a negative electrode active material, acetylene black as a conductive material, PVDF or a copolymer thereof as a binder, and NMP as a solvent.
The separator is preferably a microporous polyolefin resin such as polyethylene (PE) resin or polypropylene (PP) resin.
As a method of press-forming the power generating element 2, there is a method of heating to a temperature not higher than the softening point of the binder used for the electrode and applying a pressure of 1.0 to 7.0 MPa.

The power generation element 2 includes a non-aqueous electrolyte. The non-aqueous electrolyte is composed of a non-aqueous solvent and a supporting salt that dissolves in the non-aqueous solvent. As the non-aqueous solvent, for example, a mixture of a cyclic carbonate and a chain carbonate is used. The cyclic carbonate is preferably ethylene carbonate (EC). The chain carbonate is preferably at least one selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate (DEC), and ethyl methyl carbonate (EMC).
For example, a lithium salt having a strong electron-withdrawing property is used as the supporting salt, and specifically, LiPF ₆ , LiBF ₄ , LiCF ₃ SO ₃ , LiN (SO ₂ CF ₃ ) ₂ , or LiN (SO ₂ C _2). F ₅ ) ₂ is used. These may be used alone or in combination of two or more. The supported salt concentration in the non-aqueous electrolyte is preferably 0.5 to 1.5 mol / L.

  Although the case of the lithium ion secondary battery has been described in the above embodiment, other sealed batteries such as an alkaline storage battery may be used. In the above embodiment, the power generation element in which the belt-like positive electrode and the belt-like negative electrode are wound through the belt-like separator is used. It may be used. In the above embodiment, the positive electrode tab is connected to the lower surface of the lid, and the negative electrode tab is connected to the flange, but the positive electrode tab may be connected to the flange and the negative electrode tab may be connected to the lower surface of the lid. . In the above-described embodiment, the flat insulator and the upper insulating plate having a U-shaped cross section are used, but a combination of a U-shaped lower gasket and a flat upper insulating plate may be used. Other shapes may be used as long as the negative electrode tab is separated from the battery case and the power generation element.

  Since the battery composite lid of the present invention has excellent sealing properties, it is suitably used for sealed batteries such as lithium ion secondary batteries. The sealed battery of the present invention is suitably used as a power source for electronic devices such as portable devices and information devices.

It is a schematic longitudinal cross-sectional view of the lithium ion secondary battery which is one Embodiment of the sealed battery of this invention. FIG. 2 is a schematic longitudinal sectional view in a direction perpendicular to FIG. 1. It is a principal part longitudinal cross-sectional view of the battery composite cover in the lithium ion secondary battery of FIG. It is a principal part longitudinal cross-sectional view of the cover body in the conventional sealed battery. It is a principal part longitudinal cross-sectional view of the cover body in the other conventional sealed battery.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Battery case 2 Electric power generation element 3 Upper insulating plate 4 Cover body 4a Opening part 4b Step part 5 Welding part 6 Safety valve 7 Positive electrode tab 8 Internal terminal 8a Head part 8b Hollow shaft part 8c Eave part 9 External terminal 9a Inclined part 10 Lower gasket 11 Upper gasket 12 Negative electrode tab 13 Injection hole 14 Plug 15 Battery composite lid 20 Gap

Claims (5)

A battery composite lid comprising a lid having an opening, and a terminal portion disposed through a gasket in the opening of the lid,
The terminal portion is an external terminal exposed on the upper surface side of the lid,
A hollow shaft portion that fits into the hole of the external terminal and the hole of the gasket and presses the gasket in a direction perpendicular to the axial direction,
A head portion that is exposed and caulked to the upper surface side of the lid body from the hole of the external terminal at an upper portion of the hollow shaft portion; and a lower surface of the lid body that is formed to extend outward from a lower portion of the hollow shaft portion. An internal terminal having a flange exposed on the side;
A battery composite lid comprising:   A sealed battery using the battery composite lid according to claim 1. The battery is
A power generation element comprising an electrode group in which a belt-like positive electrode and a belt-like negative electrode are wound with a belt-like separator interposed therebetween,
A battery case having an opening and storing the power generation element;
The battery composite lid for sealing the opening of the battery case;
A negative electrode tab drawn from the negative electrode;
A positive electrode tab drawn from the positive electrode;
Comprising
The negative electrode tab is connected to the flange;
The sealed battery according to claim 2, wherein the positive electrode tab is connected to a lower surface of the lid.   The sealed battery according to claim 3, wherein the lid has a liquid injection port, and a plug is attached to the liquid injection port. A method for producing a battery composite lid according to claim 1,
(1) the step of disposing the external terminal and the internal terminal through the gasket in the opening of the lid, and inserting the hollow shaft portion of the internal terminal into the hole of the external terminal and the gasket; ,
After the step (1), a caulking punch is inserted into the hollow portion of the hollow shaft portion to spread the hollow shaft portion in a direction perpendicular to the axial direction, while pressing the gasket in a direction perpendicular to the axial direction. Caulking the head exposed from the hole of the external terminal (2);
The manufacturing method of the battery composite cover characterized by including.

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