JP2000021383A - Thin battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin battery enhanced in compactness and capacity. SOLUTION: A thin type battery is provided with a plurality of thin power generating elements 9, each of which is constructed of a sheet type positive electrode 6 and a sheet type negative electrode 7, armor resin films 10, 11 integrally and liquid-proof sealing the plurality of thin power generating elements 9, and positive and negative electrode terminals 12a, 12b, in which one end sides are connected to external connecting terminal parts 6a, 7a in the respective sheet type electrodes 6, 7 while the other end sides are hermetically led out to the outside of the armor resin films 12a, 12b. The sheet type positive electrode 6 in the thin power generating element 9 is provided with a positive electrode collector in which a positive active material is stuck and carried while the external connecting terminal part 6a is projected. The sheet type negative electrode 7 in the thin power generating element 9 is layered on the sheet type positive electrode 6 main face via an ion-conductive sheet type separator 8 and provided with a negative collector in which a negative active material is adhesively carried while the external connecting terminal part 7a is projected. Among the external connecting terminal parts 6a, 7a in the plurality of thin power generating elements 9 of the thin battery, the terminal parts with the same polarity are matched mutually and electrically connected and fixed inside each of the cylinder bodies 12a, 12b so as to constitute positive and negative electrodes respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin battery,
More specifically, the present invention relates to a thin battery having a plurality of thin power generating elements integrated therein to achieve high capacity.

[0002]

2. Description of the Related Art Small, lightweight, thin, large-capacity, and high-voltage power sources are required for power supplies for portable telephones and television cameras. For example, a positive electrode layer, a polymer electrolyte layer, and a negative electrode layer are required. 0.5 mm thick with electrode elements (power generation elements) configured to be stacked and integrated into a sheet (thin)
Some lithium non-aqueous solvent batteries are also known (eg, US Pat. No. 5,296,318).

FIG. 4A is a perspective view and FIG.
FIG. 1A shows an example of a configuration of a main part of a conventional thin battery in a cross-section along the line AA in FIG. 4 (a) and 4 (b), reference numeral 1 denotes a sheet-like separator supporting an electrolytic solution, 2 denotes a lithium-containing metal oxide laminated and arranged on one main surface of the sheet-like separator 1 as an active material, and The sheet-shaped positive electrode 3 having a positive electrode current collector has a lithium metal or a carbonaceous material that occludes / releases lithium as an active material, which is laminated and disposed on the other main surface of the sheet-shaped separator 1, and has a negative electrode current collector. It is a sheet-shaped negative electrode having.

Here, the sheet-like separator 1 is made of an electrolyte-retaining polymer, for example, hexafluoropropylene-
It is a polymer-electrolyte system such as a vinylidene fluoride copolymer. The sheet-shaped positive electrode 2 is composed of an active material such as a metal oxide containing lithium, an electrolyte-retaining polymer, and a positive electrode current collector. Further, the sheet-shaped negative electrode absorbs and releases lithium ions, for example. Active material, an electrolyte-retaining polymer, and a negative electrode current collector.

[0005] The sheet-like positive electrode 2 is formed by welding and connecting one end of an aluminum foil piece to a positive electrode current collector.
However, the sheet-shaped negative electrode 3 is provided with negative electrode terminals 3a by welding and connecting one end of a copper foil piece to a negative electrode current collector.
These sheet electrodes 2 and 3 and sheet separator 1 are laminated to form a power generating element unit 4.

Further, 5, 6 are the sheet-like electrodes 2, 3
And an exterior resin film for liquid-tight or air-tight sealing of a power generation element composed of a laminate of the sheet-like separator 1. In order to increase the battery capacity, a plurality of the power generation elements 4 are incorporated, and both the positive and negative electrode terminals 2 a , 3a are led out of the encapsulant formed by the exterior resin films 5, 6 while sealing them in a liquid-tight or air-tight manner.

In order to manufacture this kind of lightweight and flexible thin battery, a plurality of power generating units each comprising a combination of the sheet-shaped positive electrode 2, the sheet-shaped separator (polymer-electrolyte) 1 and the sheet-shaped negative electrode 3 are laminated. Element 4 is prepared. Then, the plurality of power generating elements 4 are connected to each electrode terminal.
2a and 3a are aligned and welded, and exterior resin films 5 and 6 are laminated and arranged on both sides (so that one resin film is folded and both main surfaces are wrapped), and each electrode connected to the current collector The peripheral edges 5a and 6a of the exterior resin films 5 and 6 are hermetically bonded or integrated via heat bonding or an adhesive layer while the terminals 2a and 3a are collectively led out to the outside. .

[0008]

However, the thin battery having the above structure has the following disadvantages. That is, in a thin battery including a plurality of power generating elements 4, electrode terminals 2 a and 3 a each having one end connected to each current collector of the power generating elements 4 are directly extended and collectively or collectively. Sealed out.

In other words, the two electrode terminals 2a, 3a extending for each power generating element 4 are arranged in a state where the electrode terminals 2a or the electrode terminals 3a are simply overlapped (collected state). It is sealed and led out from the sealing portions of the resin films 5 and 6. By the way, in the sealing and leading-out of the two electrode terminals 2a and 3a, if the welding and joining sealing portions of the exterior resin films 5 and 6 are set small in order to reduce the size, the two electrode terminals 2a and 3a are collectively assembled. There is a tendency that liquid leakage or the like is likely to be caused from a portion to be sealed and led out. In addition, if the area required for welding and joining and sealing the exterior resin films 5 and 6 is made relatively large, there is a problem that the compactness of a thin battery is impaired or the battery capacity is reduced.

In any of the above cases, both electrode terminals 2
In the configuration in which a and 3a are simply overlapped and assembled and sealed and led out, the stripped electrode terminals 2a and 3a
Since 3a is easily damaged, the reliability of electrical connection may be impaired.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and has as its object to provide a thin battery having a more compact or higher capacity.

[0012]

According to the first aspect of the present invention, there is provided a sheet-shaped positive electrode having a positive electrode current collector on which a positive electrode active material is attached and supported, and an external connection terminal portion protruded, and the sheet-shaped positive electrode. Attach and carry the negative electrode active material laminated and arranged via a sheet-like separator having ion conductivity on the main surface,
And a plurality of thin power generating elements each comprising a sheet-shaped negative electrode having a negative electrode current collector having a protruding external connection terminal portion, and an exterior resin film integrally and liquid-tightly sealing the plurality of thin power generating elements. And a positive and negative electrode terminal connected to the external connection terminal portion of each of the sheet-like electrodes and the other end side of which is sealed and led out of the exterior resin film. In the power generating element, the external connection terminal portions having the same polarity are aligned with each other, and the external connection terminal portions having the same polarity are electrically connected and fixed in one cylinder to form both positive and negative electrode terminals. It is a thin battery characterized by the following. According to a second aspect of the present invention, in the thin battery according to the first aspect, the liquid-tight sealing with the exterior resin film is performed by heat-sealing the edges of the exterior resin film.

According to a third aspect of the present invention, in the thin battery according to the first or second aspect, the electrical connection between the external connection terminals in one cylinder is performed by crimping of the cylinder. It is characterized by.

In the first to third aspects of the present invention, the positive electrode current collector may be, for example, an aluminum foil, an aluminum mesh,
It is an aluminum band metal, an aluminum punch metal, or the like, and the positive electrode current collector has an external connection terminal protruding therefrom. The external connection terminal section
Generally, the positive electrode current collector is formed in an extended portion and in a region where the positive electrode active material is not applied. However, a configuration in which an aluminum foil piece or the like is welded to the positive electrode current collector may be used.

On the other hand, the negative electrode current collector is made of copper foil, copper extra band metal, copper punch metal, or the like, and the negative electrode current collector also has a protruding external connection terminal portion. And
The external connection terminal portion of the negative electrode current collector is also generally formed in an extended portion of the negative electrode current collector and in a region where the negative electrode active material is not applied. Or the like may be welded.

In the first to third aspects of the present invention, the positive electrode active material to which the positive electrode current collector is attached and supported is a lithium-containing metal oxide that absorbs and releases lithium ions, such as a lithium-manganese composite oxide and a lithium-containing cobalt oxide. Products, lithium-containing nickel-cobalt oxide, lithium-containing amorphous vanadium pentoxide, manganese dioxide, chalcogen compounds, and the like.

The negative electrode active material that the negative electrode current collector adheres and carries is one that absorbs and releases lithium ions, and examples thereof include fired products of bisphenol resin, polyacrylonitrile, and cellulose, and fired products of coke and pitch. , These are natural or artificial graphite, carbon black, acetylene black, ketjen black,
A form containing nickel powder, nickel powder, or the like may be employed.

Further, the electrolytic solution which is impregnated and supported by the separator interposed between the above-mentioned sheet-like positive electrode and negative electrode to form an ion conductor includes, for example, ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate and the like. Lithium perchlorate, lithium hexafluorophosphate, lithium borotetrafluoride, lithium arsenide hexafluoride, lithium trifluoromethanesulfonate, etc. in a nonaqueous solvent such as diethyl carbonate, methyl ethyl carbonate, etc. Dissolved to an extent. Here, examples of the electrolyte-holding polymer-electrolyte system that functions as a separator include polymers such as hexafluoropropylene-vinylidene fluoride copolymer.

In the invention according to any one of claims 1 to 3, the external connection terminal sections having the same polarity are put together for each external connection terminal section group of the positive electrode and the negative electrode. While making the connection, the cylinders constituting the positive and negative electrode terminals, for example, the positive electrode is made of aluminum, the negative electrode is made of copper, and its inner diameter, length, thickness, etc.
It is appropriately selected and set according to the number of stacked power generating elements and the width and length of the external connection terminal. In addition, when the external connection terminals having the same polarity are put together, the ends are inserted, and when the electrical connection is made integrally with the cormorants, the cylinder into which the ends are inserted is pressurized, and the inserted ends are crimped. Although the reliability of the electrical connection can be improved by integrally integrating and fixing, it may be integrated and fixed by, for example, filling with solder or conductive paste.

In the first to third aspects of the present invention, the exterior resin film for integrally sealing a plurality of power generating elements stacked and arranged is, for example, a polyethylene resin film or a polypropylene resin film having a thickness of about 0.02 to 0.5 mm. Is mentioned. The liquid-tight sealing with the exterior resin film is an easy means of heat-sealing the edges of the exterior resin film positioned and arranged on both sides of the power generating element by heating or beam irradiation. An adhesive may be inserted instead of heat fusion.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment will be described below with reference to FIGS. 1 (a) and 1 (b), FIG. 2 and FIGS. 3 (a) and 3 (b).

FIGS. 1 (a) and 1 (b) are a transparent plan view showing a main configuration of a thin battery according to an embodiment, and a cross-sectional view taken along the line BB of FIG. 1 (a). In FIGS. 1 (a) and 1 (b), reference numeral 6 denotes a sheet-shaped positive electrode having a positive electrode current collector on which a positive electrode active material is attached and carried and an external connection terminal 6a is protruded, and 7 denotes the sheet-shaped positive electrode 6. A sheet-shaped negative electrode having a negative electrode current collector in which a negative electrode active material laminated and arranged on a main surface of the substrate through a sheet-shaped separator 8 having ion conductivity is attached and supported, and an external connection terminal portion 7a is projected. This stacked type constitutes the thin power generating element 9.

The reference numerals 10 and 11 denote a plurality of the thin power generating elements 9 in a state where the external connection terminals 6a and 7a of the same polarity are aligned and laminated, respectively, and the edges 10a and 11a are thermally fused. This is a folded exterior resin film that is integrally and liquid-tightly sealed by wearing. Further, 12a and 12b are both positive and negative electrode terminals connected to the external connection terminal portions 6a and 7a of the sheet electrodes 6 and 7, respectively, and the other end is sealed and led out of the exterior resin films 10 and 11. It is. Here, the external connection terminal portions 6a and 7a having the same polarity are connected to the external connection terminal portions 6 having the same polarity.
a and 7a collectively form one cylinder each.
One end side is inserted into a and 12b and is electrically connected by ultrasonic welding to form both positive and negative electrode terminals.

Next, an example of manufacturing and assembling the thin battery having the above configuration will be described.

Preparation of Sheet-Type Positive Electrode After dissolving vinylidene fluoride-hexafluoropropylene copolymer (trade name: KYNAR2801, manufactured by Elphatochem Co.) in acetone, dibutyl phthalate and lithium-containing cobalt oxide ( L
iCoO ₂ ) was added and mixed to prepare a positive electrode paste. Next, at one end of a porous current collector made of aluminum lath metal prepared in advance, the positive electrode paste was applied using a knife coater while leaving an uncoated portion width of 10 mm, followed by drying. Drying was performed with air. After that, the outer dimensions of the positive electrode paste-coated part were 40 × 60 mm, and the dimensions of the uncoated part were 10 ×
The sheet-shaped positive electrode 6 was cut into 10 mm, having an electrolyte-unimpregnated positive electrode layer on both sides, and having an uncoated portion serving as an external connection terminal portion 6a protruding (extending).

Preparation of sheet-shaped negative electrode After dissolving vinylidene fluoride-hexafluoropropylene copolymer (trade name; KYNAR2801, manufactured by Elphatochem Co.) in acetone, dibutyl phthalate and mesofused pitch-based carbon fiber were added to this ascentone solution. (Manufactured by Petka) was added and mixed to prepare a negative electrode paste. Next, at one end of a porous current collector made of copper lath metal prepared in advance, the paste for the negative electrode was applied using a knife coater while leaving an uncoated portion width of 10 mm, and dried air was applied. For drying. After that, the outer dimensions of the negative electrode paste-coated part were 40 × 60 mm, and the dimensions of the uncoated part were 10 ×
The sheet-shaped negative electrode 7 was cut into 10 mm, and had a negative electrode layer impregnated with no electrolyte on both surfaces, and had an uncoated portion serving as an external connection terminal portion 7a protruding (extending).

Preparation of Solid Polymer Electrolyte Material After dissolving vinylidene fluoride-hexafluoropropylene copolymer (trade name: KYNAR2801, manufactured by Elphatochem Co.) in acetone, dibutyl phthalate was added to this ascentone solution and mixed. Paste was prepared. Next, it was applied to a smooth glass plate surface prepared in advance and dried with dry air. Thereafter, the solid polymer electrolyte material 8 was prepared by peeling off the glass plate and cutting it into an outer dimension of 40 × 60 mm to produce a solid polymer electrolyte material 8 not impregnated with an electrolyte.

Preparation of Non-Electrolyte Solution LiPF ₆ (electrolyte) was added to a mixed solvent of ethylene carbonate and dimethyl carbonate (non-aqueous solvent) at a volume ratio of 1: 1.
Was dissolved at a rate of 1 mol / l to prepare a non-electrolytic solution.

As shown in perspective in FIG. 2, a solid polymer electrolyte material 8 and a sheet-shaped positive electrode 6 are sequentially positioned and laminated on both main surfaces of the sheet-shaped negative electrode 7 prepared above.
The sheet was passed between rigid rollers heated to 130 ° C. and heated and pressed to produce a thin power generating element 9 having a thickness of 1.0 mm. Thereafter, the thin power generating element 9 was immersed in methanol to elute and remove dibutyl phthalate in the sheet-shaped positive electrode 6, the sheet-shaped negative electrode 7, and the solid polymer electrolyte material 8, thereby forming a porous structure.

Next, the two thin power generating elements 9 having the porous structure are stacked so that the external connection terminal portions 6a of the same polarity are located at the same position, and the external connection terminal portions 6a are superposed with each other. Joined by sonic welding. Thereafter, as shown in perspective in FIG. 3 (a), a cylindrical body 12a having a thickness of 1 mm, an outer diameter of 11 mm, and a length of 20 mm is fitted and attached to the externally connected external connection terminal portion 6a. , External connection terminal 7a made of copper
Fit a cylindrical body 12b with a diameter of 11 mm, an outer diameter of 11 mm and a length of 20 mm. Subsequently, as shown in a perspective view in FIG. 3 (b), the fitted cylindrical body 12a and the external connection terminal portion 6a are further connected to the cylindrical body 1a.
2b and the external connection terminal 7a were each subjected to ultrasonic welding to form electrode terminals.

On the other hand, an ionomer resin film, an aluminum foil and a polyethylene terephthalate resin film are laminated and integrated to a thickness of 0.1 mm and an outer dimension of 70 × 1.
A 53 mm exterior resin film was prepared. Thereafter, the ionomer resin film is turned inside, and the central part in the long side direction is folded (returned) 10, 11 and the two sides in the width direction are each heat-fused over a width of 10 mm to produce an exterior body having one end opened. did.

The laminated body of the thin power generating element 9 is housed and arranged in the exterior body such that one end of the laminated body extends from the opening to the tip of the electrode terminal 12a, 12b. Injected. After the injection of the non-aqueous electrolyte, the openings (extending portions of the tip ends of the electrode terminals 12a and 12b) of the exterior body are heat-sealed over a width of 10 mm to hermetically seal the laminate of the thin power generation elements 9 and Then, a thin battery having a thickness of 2.2 mm and an outer dimension of 70 × 75 mm was produced by hermetically leading out the electrode terminals 12a and 12b.

In the above configuration, the external dimensions of the thin power generating element are set to 40 × 50 mm, and instead of fitting the cylinders 12a, 12b to the external connection terminal portions 6a, 7a, the electrode terminals 2a, 3a have thicknesses of Aluminum foil piece and copper foil piece of 0.1mm, outer dimensions of 10x30mm are ultrasonically welded, and air-tight lead-out with electrode terminal 2a overlapped under the same conditions, thickness 2.2mm, outer dimensions A thin battery of 70 × 75 mm was produced (Comparative Example). Here, the length is set long in order to prevent the aluminum foil pieces and the copper foil pieces forming the electrode terminals 2a and 3a from being damaged by stress or the like. Therefore, when the outer dimensions are 70 × 75 mm, the outer dimensions of the power generating element are reduced.

The average battery capacity was determined for 100 thin batteries according to the example and 100 thin batteries according to the comparative example, which were manufactured under the conditions for manufacturing and assembling the thin batteries, respectively. Table 1 shows the volumetric efficiency excluding the electrode terminal portion.

[0035] As can be seen from Table 1, in the case of the thin battery according to the present invention, the battery capacity and the volumetric efficiency are larger than those of the conventional thin battery (comparative example) in which the external dimensions are set to be the same. If so, miniaturization will be achieved. The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the invention. For example, in the configuration of the power generating element, a sheet-shaped positive electrode and a sheet-shaped negative electrode may be set as a pair, or a configuration in which three or more power generating elements are stacked may be employed. Also, the exterior resin film may be a multi-layer type or a single-layer type other than those exemplified, and the sealing and sealing of the edge may be performed by an adhesive or the like.

[0036]

According to the first to third aspects of the present invention, the positive and negative electrode terminals of the polymer thin-film battery have external connection terminal portions corresponding to each cylinder functioning as the electrode terminals. The package resin film is sealed and led out while being inserted into the housing and electrically and mechanically fixed. Therefore, the size of the reduced portion can be reduced. Alternatively, since the electrode element can be set large corresponding to the reduced region, the capacity of the lithium polymer battery can be increased accordingly. Moreover, since the electrode terminals derived from the exterior resin film are less likely to be disconnected due to vibration or the like, a highly reliable lithium polymer battery is provided.

[Brief description of the drawings]

FIG. 1A is a perspective plan view showing a configuration of a main part of a thin battery according to an embodiment, and FIG. 1B is a cross-sectional view taken along the line BB of FIG.

FIG. 2 is a perspective view showing a configuration procedure of a power generating element of the thin battery according to the embodiment.

FIG. 3 is an explanatory view showing a procedure for attaching an electrode terminal to a power generating element of the thin battery according to the embodiment. FIG. 3 (a) is a perspective view before attaching a cylindrical body forming an electrode terminal to an external connection terminal portion. (B) is a perspective view after mounting and fixing.

FIG. 4A is a perspective plan view showing a configuration of a main part of a conventional thin battery, and FIG. 4B is a cross-sectional view taken along the line AA of FIG.

[Explanation of symbols]

1, 8 separator Separator 2, 6 sheet-shaped positive electrode 2a, 12a positive electrode terminal 3, 7 sheet-shaped negative electrode 3a, 12b negative electrode terminal 4, 9 power generation element unit 6a, 7a … External connection terminals 5,6,10,11… Outer resin film 5a, 6a, 10a, 11a… Outer resin film edge (sealing part)

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 5H011 AA01 AA03 AA17 CC02 DD13 EE04 FF02 GG09 HH02 5H022 AA09 BB11 BB12 CC02 CC12 CC16 CC21 EE06 KK08 5H029 AJ03 AJ11 AJ15 AL03 AL06 AM03 CJ05 DJ03 DJ05EJ11

Claims (3)

[Claims] 1. A sheet-shaped positive electrode having a positive electrode current collector on which a positive electrode active material is attached and carried and an external connection terminal is projected, and a sheet-shaped separator having an ion-conductive surface on the main surface of the sheet-shaped positive electrode. A plurality of thin power-generating elements comprising a sheet-like negative electrode having a negative electrode current collector having a negative electrode current collector provided with a negative electrode active material laminated and disposed via the external connection terminal portion, and An exterior resin film that integrally and liquid-tightly seals the thin power generating element; and positive and negative electrodes that are connected to external connection terminals of each of the sheet-like electrodes and whose other ends are sealed and led out of the exterior resin film. A thin battery having electrode terminals, wherein the plurality of thin power generating elements are arranged such that external connection terminal portions of the same polarity are aligned with each other, and the external connection terminal portions of the same polarity are formed in a single cylindrical body. Electrically connected and fixed positive -A thin battery comprising negative electrode terminals respectively. 2. A liquid-tight sealing with an exterior resin film,
2. The thin battery according to claim 1, wherein the outer edges of the outer resin film are heat-sealed. 3. The thin battery according to claim 1, wherein the external connection terminal portions are electrically connected to each other within the cylinder by welding the cylinder.