JP2006324114A - Thin battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin battery difficult to deform a lead terminal. <P>SOLUTION: A lithium primary battery 1A contains first portions 2a, 3a, and second portions 2b, 3b in which frame members 2, 3 having functions as a sealing material extend in the same direction as a positive electrode side lead terminal and a negative electrode side lead terminal 7t, and support the positive electrode side lead terminal and the negative electrode side lead terminal 7t. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a thin battery with high flexibility.

Recently, the demand for IC cards and RFIDs with built-in microcomputers is expanding as simple storage media that replace magnetic cards. Many non-contact type data carriers generally use electromotive force due to electromagnetic induction, but there are attempts to provide a built-in power source in order to achieve multiple functions. For example, the batteries disclosed in the following Patent Documents 1 and 2 are called paper batteries, and demand for IC cards, active RFIDs, and the like is expected to increase.
Japanese Patent No. 2935427 JP-A-8-055627

  A thin battery such as a paper-type battery has excellent flexibility and flexibility, but the lead terminal connected to the current collector is easily deformed by an external force. The thin batteries shown in Patent Documents 1 and 2 have a structure in which strip-shaped lead terminals extend outward from a battery main body including a power generation element. Usually, since the metal foil is only exposed in the lead terminal, deformation such as bending or twisting may occur due to external force. Even when there is no deformation, the work to connect the lead terminal of a thin battery to the terminal of a circuit of an electronic device or the like needs to be cautious in order to reduce the incidence of defective products due to damage to the lead terminal . If the lead terminal is bent, it is necessary to prepare the shape one by one, and that alone causes a decrease in productivity. Thus, the deformation of the lead terminal significantly reduces the product value of the thin battery.

  An object of the present invention is to provide a thin battery in which a lead terminal is not easily deformed by an external force, and the work for connecting the lead terminal to a terminal of a circuit of an electronic device or the like incorporating the battery is easy.

Means for Solving the Problems and Effects of the Invention

  In order to solve the above problems, a thin battery of the present invention includes a separator, a positive electrode active material layer disposed on one side of the separator, a negative electrode active material layer disposed on the other side of the separator, and A resin frame member surrounding the separator, the positive electrode active material layer, and the negative electrode active material layer, and the frame member fixed to the frame member so as to close one opening of the frame member, and holding the positive electrode active material layer between the separator A positive electrode current collector, and a negative electrode current collector that is fixed to the frame member so as to close the other opening of the frame member and holds a negative electrode active material layer between the separator and the frame member, the positive electrode current collector And a lead terminal connected to the positive electrode current collector or the negative electrode current collector and having a shape protruding outward in a plane perpendicular to the thickness direction of the thin battery. The second part that extends in the same direction as the lead and supports the lead terminal If, the main feature that it comprises a.

  If the lead terminal is supported by the frame member as in the present invention, the lead terminal can be prevented from being deformed by an external force. In addition, since the frame member that fixes the current collector plays a role of supporting the lead terminal, there is no problem of increasing the thickness of the battery. Furthermore, there is no substantial increase in the number of parts and the cost is low.

  In a preferred embodiment, the lead terminal supported by the frame member includes a positive electrode side lead terminal connected to the positive electrode current collector and a negative electrode side lead terminal connected to the negative electrode current collector. The positive electrode side lead terminal and the negative electrode side lead terminal have a strip shape extending outward in the plane of the thin battery and can be provided at alternate positions in plan view. And while the positive electrode current collector and the negative electrode current collector are separated into one surface side and the other surface side by the first part of the frame member, the tip of the second part of the frame member In this position, at least one of the positive electrode side lead terminal and the negative electrode side lead terminal is folded back to the opposite surface side, so that the positive electrode side lead terminal and the negative electrode side lead terminal are exposed in the same plane. According to such a structure, while the lead terminal is supported by the second portion of the frame member, the exposure direction of the lead terminal can be freely adjusted according to the terminal arrangement of the device incorporating the thin battery of the present invention. it can.

  Also, considering the convenience of equipment incorporating a thin battery, both the positive lead terminal and the negative lead terminal are exposed on both the first main surface side and the second main surface side of the thin battery. It is more desirable. This structure can be realized by folding both the positive electrode side lead terminal and the negative electrode side lead terminal to the respective opposite surfaces at the tip position of the second portion of the frame member.

  The lead terminal supported by the frame member is preferably made of metal integrally formed with the current collector. Specifically, an active material filling chamber is formed between a positive electrode current collector and a negative electrode current collector, and a positive electrode current collector is accommodated by accommodating a separator, a positive electrode active material layer, and a negative electrode active material layer in the active material filling chamber. A structure in which the electric body and the negative electrode current collector are used as a substantial exterior material is employed. When such a structure is adopted, a container as a separate component from the current collector is not necessary, which contributes to a reduction in the number of components and cost. In addition, since such a container is not used, it is advantageous for reducing the thickness, and a device for drawing out the lead terminal from the container is unnecessary. Furthermore, since the current collector and the lead terminal are integrally formed, there is no step at the connection location between them, and a flat battery with a thin shape can be easily realized.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a perspective view of a lithium primary battery which is an embodiment of a thin battery according to the present invention. FIG. 2 is a cross-sectional view taken along line AA in FIG. In this specification, “main surface” is used as a term indicating a surface having the largest area.

  The lithium primary battery 1A is generally square and plate-shaped, and includes frame members 2 and 3 as a sealing material, a positive electrode active material layer 4, a positive electrode current collector 6, a negative electrode active material layer 5, a negative electrode current collector 7 and a separator 9. Is provided. The positive electrode current collector 6 and the negative electrode current collector 7 are fixed to the frame members 2 and 3 so as to close the openings of the frame members 2 and 3, respectively, and also serve as an exterior material of the lithium primary battery 1A. The positive electrode current collector 6 and the negative electrode current collector 7 are integrally formed with strip-shaped lead terminals 6t and 7t, respectively, as power extraction portions. The lead terminals 6t and 7t extend in a form protruding from the current collectors 6 and 7 in the outer direction in the plane orthogonal to the thickness direction of the lithium primary battery 1A. In order to prevent the lead terminals 6t and 7t from being deformed by receiving an external force, the frame members 2 and 3 are extended in the same direction as the lead terminals 6t and 7t to support the lead terminals 6t and 7t. The frame members 2 and 3 function as reinforcing materials for the lead terminals 6t and 7t.

  As shown in FIG. 2, the frame members 2 and 3 are substantially composed of a positive electrode side frame member 2 and a negative electrode side frame member 3. The positive electrode side frame member 2 and the negative electrode side frame member 3 are bonded to each other on the facing surfaces. An active material filling chamber 10 is formed by the frame members 2 and 3, the positive electrode current collector 6 and the negative electrode current collector 7, and the separator 9, the positive electrode active material layer 4 and the negative electrode active material layer 5 are accommodated in the active material filling chamber 10. As a result, the battery body 14 is formed. Further, the positive electrode current collector 6 is bonded to the positive electrode side frame member 2 and the negative electrode current collector 7 is bonded to the negative electrode side frame member 3 so as to be located on the side opposite to the separator 9. Thereby, the seal part 11 which maintains the airtightness of the battery main body part 14 is formed. By fixing the peripheral edge portion 9k of the separator 9 to the negative electrode side frame member 3, the active material filling chamber 10 is divided into a positive electrode side where the positive electrode active material layer 4 is arranged and a negative electrode side where the negative electrode active material layer 5 is arranged. It is divided. In the active material filling chamber 10, the positive electrode active material layer 4 is held between the positive electrode current collector 6 and the separator 9, and the negative electrode active material layer 5 is held between the negative electrode current collector 7 and the separator 9. Yes. With such a structure, the current collectors 6 and 7 can be used also as an exterior material of the lithium primary battery 1A.

  As shown in FIG. 2, the frame members 2 and 3 include first portions 2a and 3a that are portions that form the seal portion 11, and second portions 2b and 3b that are portions that support the lead terminals 6t and 7t. Further, the negative electrode side frame member 3 includes an opening peripheral edge portion 3 c that fixes the outer peripheral portion 9 k of the separator 9. The positive electrode current collector 6 and the negative electrode current collector 7 are in a relative positional relationship that is separated into one surface side and the other surface side by the first portions 2a and 3a of the frame members 2 and 3. In addition, the positive lead terminal 6t is folded 180 degrees toward the negative electrode side and the negative lead terminal 7t is folded 180 degrees toward the positive electrode side at the tip positions of the second portions 2b and 3b of the frame members 2 and 3, respectively. As a result, a terminal arrangement is formed in which the positive lead terminal 6t and the negative lead terminal 7t are exposed on both the front and back surfaces. Since the terminals are exposed on both sides, when the lithium primary battery 1A is mounted on a device, it is possible to reverse the front and back according to the terminal arrangement of the device.

  The current collectors 6 and 7 in which the lead terminals 6t and 7t are integrally formed can be obtained by cutting a metal foil produced by rolling into a predetermined shape. The lead terminals 6t and 7t integrally formed with the current collectors 6 and 7 are adjacent to the same side of the lithium primary battery 1A having a rectangular shape as a whole, but have a constant interval when projected in the thickness direction. It is staggered to occur. In this way, even if the positive electrode side lead terminal 6t and the negative electrode side lead terminal 7t are folded back 180 degrees to the opposite surfaces, they are not short-circuited. Further, the length of the positive electrode side lead terminal 6t is adjusted to be longer than the length of the second portions 2b and 3b of the frame members 2 and 3 in the longitudinal direction of the positive electrode side lead terminal 6t and shorter than twice. Therefore, the positive electrode side lead terminal 6 t is not short-circuited with the negative electrode current collector 7. The same applies to the negative-side lead terminal 7t.

  Further, the lead terminals 6t and 7t that are folded back 180 degrees and wrap around to the opposite surface side are bonded to the second portions 2b and 3b of the frame members 2 and 3, respectively. In the frame members 2 and 3, at least the surface layer portions in contact with the current collectors 6 and 7 and the lead terminals 6t and 7t are made of a hot-melt resin adhesive. Therefore, if the second portions 2b and 3b of the frame members 2 and 3 are melted and solidified in contact with the lead terminals 6t and 7t, the lead terminals 6t and 7t are caused by the adhesive action of the frame members 2 and 3 themselves. Can be fixed to the second portions 2b and 3b of the frame members 2 and 3. However, the lead terminals 6t and 7t may be fixed using an adhesive separate from the frame members 2 and 3.

  The individual parts will be described in detail. The frame members 2 and 3 are thin resin sheets having a shape like a window frame, and are made of a thermoplastic resin having a heat-sealing property so as to have a function as a sealing material. For example, ethylene vinyl acetate (EVA) and ethylene / methacrylic acid co- A resin sheet on which a hot-melt resin adhesive layer such as a polymer (EMAA), acid-modified polyethylene (PE-a), or acid-modified polypropylene (PP-a) is formed can be used as the frame members 2 and 3. Of course, a resin sheet of a single layer of hot melt type resin adhesive may be used.

The positive electrode active material layer 4 includes, for example, 60% by mass or more and 70% by mass or less of a positive electrode active material, 1% by mass or more and 5% by mass or less of a conductive auxiliary agent, and 25% by mass or more and 35% by mass or less of an electrolytic solution. It consists of a positive electrode composite. As the positive electrode active material, a transition metal oxide powder that forms a composite oxide with lithium such as MnO ₂ can be used. A carbon material such as acetylene black can be used for the conductive assistant. The electrolyte is an organic solvent such as dimethoxyethane (DME), ethylene carbonate (EC), propylene carbonate (PC), or lithium salt such as lithium perchlorate salt (LiClO ₄ ) or lithium triflate salt (LiCF ₃ SO ₃ ). Is a non-aqueous electrolyte in which is dissolved.

  The negative electrode active material layer 5 is composed of a lithium foil. It is also possible to use lithium alloy foil (for example, lithium-aluminum alloy) instead of lithium foil. The surface of the lithium foil used for the production of the lithium primary battery 1A may be deactivated in advance. As a result, if the work is performed for a short time, it is not necessary to perform the work in a dry room, and the work can be performed in a normal dry room. In addition, each mass of the positive electrode active material layer 4 and the negative electrode active material layer 5 is adjusted so that the battery capacity of a positive electrode may become larger than the battery capacity of a negative electrode. This prevents the lithium foil forming the negative electrode active material layer 5 from remaining after complete discharge.

  As the material for the current collectors 6 and 7 and the lead terminals 6t and 7t, one kind selected from a highly conductive metal group consisting of copper, copper alloy, stainless steel, aluminum, aluminum alloy, nickel and nickel alloy is preferably used. Can be used. In particular, stainless steel is preferable because it is excellent in workability, corrosion resistance, and economy. In order to obtain long-term stability, it is important that the current collector itself does not elute into the battery. In this regard, stainless steel has a minute. Specifically, SUS301, SUS304, SUS316, SUS316L, which are typical as austenitic stainless steel, and SUS631, which is typical as precipitation hardened stainless steel, are also excellent in spring properties, and therefore their use is recommended.

  The separator 9 is a thin film that separates the positive electrode and the negative electrode and sufficiently penetrates the electrolyte, and has a porous and multilayer structure. Specifically, a nonwoven fabric made of a resin such as polyethylene or polypropylene can be used. In the present embodiment, a polyethylene porous sheet is used for the separator 9.

The thickness of the lithium primary battery 1A of the present invention is not particularly limited. For example, when the thickness is 1.0 mm or less, the effect of reinforcing the lead terminals 6t and 7t and the effect of improving the pressure resistance of the battery itself. Can be obtained remarkably. When the lithium primary battery 1A is designed as a thin battery for an ISO standard IC card, the thickness of each component can be adjusted within the following range.
Positive electrode active material layer 4 ... 100 μm or more and 300 μm or less Negative electrode active material layer 5 30 μm or more and 150 μm or less Positive electrode side frame member 2 30 μm or more and 200 μm or less (same for negative electrode side frame member 3)
Positive electrode current collector 6: 10 μm or more and 100 μm or less (the same applies to the negative electrode current collector 7)
Separator 9: 10 μm or more and 60 μm or less Maximum thickness of primary lithium battery 1A: 0.40 mm or less (desirably 0.35 mm or less)

(Second embodiment)
As in the lithium primary battery 1B shown in FIG. 3, only one of the positive electrode side lead terminal 6T and the negative electrode side lead terminal 7t may be folded back to the opposite surface side. That is, the negative electrode side lead terminal 7t is formed longer than the positive electrode side lead terminal 6T, and the long negative electrode side lead terminal 7t is opposite at the tip positions of the second portions 2b and 3b of the frame members 2 and 3. Fold it back to the face side. On the other hand, the positive electrode side lead terminal 6T is directly bonded to the second portion 2b of the frame member 2 without being folded back so as to wrap around to the opposite surface side. In this way, the trouble of turning back the positive electrode side lead terminal 6T can be saved. Further, both the positive electrode side lead terminal 6T and the negative electrode side lead terminal 7t are exposed to the same surface (the front surface or the back surface of the lithium primary battery 1B), which is the same as the previous embodiment. Therefore, it is easy to connect these lead terminals 6T and 7t to the terminal of the device incorporating the lithium primary battery 1B.

(Third embodiment)
By the way, when it is sufficient to achieve the purpose of preventing the deformation of the lead terminal due to an external force, it is not essential to mold the lead terminal back to the opposite surface. That is, like the lithium primary battery 1 </ b> C shown in FIG. 4, both the positive electrode side lead terminal 6 </ b> T and the negative electrode side lead terminal 7 </ b> T may be bonded directly to the frame members 2 and 3 without being folded back. The lead terminals 6T and 7T of the lithium primary battery 1C are adjusted in length so that the tips are positioned in front of the outer peripheral edges of the frame members 2 and 3 (in other words, the tip positions of the second portions 2b and 3b). Has been made. Each lead terminal 6T, 7T is divided into a first main surface side and a second main surface side by frame members 2, 3.

(Fourth embodiment)
As already described for the lithium primary battery 1A, when the current collectors 6 and 7 are also used as an exterior material, the current collectors 6 and 7 can be used without being exposed. Therefore, it is possible to take out power directly from the current collectors 6 and 7 without bothering to provide lead terminals. That is, a lead terminal is connected to at least one of the positive electrode current collector and the negative electrode current collector, and the lead terminal is folded back 180 degrees to the opposite surface side. Like the lithium primary battery 1D of FIG. 5, the positive electrode current collector 6 is not provided with a lead terminal, while the negative electrode current collector 7 is integrally formed with a strip-like negative electrode side lead terminal 7t. The negative electrode side lead terminal 7t is folded 180 degrees to the positive electrode side and fixed to the frame members 2 and 3. Even if it does in this way, it will not change that the extraction part of electric power exists on the same surface substantially. Therefore, it is easy to connect the lithium primary battery 1D to a terminal of a device incorporating the lithium primary battery 1D.

(Fifth embodiment)
The lithium primary battery 1E shown in FIG. 6 is different from the lithium primary battery 1A shown in FIG. 1 in the positions of the lead terminals 6t and 7t. Other points are common. According to the lithium primary battery 1 </ b> E shown in FIG. 6, the lead terminals 6 t and 7 t are positioned at the corners of the substantially rectangular current collectors 6 and 7. Thus, the positions of the lead terminals 6t and 7t are not limited to the vicinity of the center of the current collectors 6 and 7. That is, the narrower portions than the current collectors 6 and 7 can be regarded as the lead terminals 6t and 7t. Further, the configuration in which the direction in which the positive electrode side lead terminal 6t extends and the direction in which the negative electrode side lead terminal 7t extends is not essential. For example, a form in which the longitudinal direction of the positive electrode side lead terminal 6t and the longitudinal direction of the negative electrode side lead terminal 7t intersect is also possible.

The perspective view of the lithium primary battery concerning this invention. AA sectional drawing of FIG. The perspective view of the lithium primary battery of 2nd embodiment. The perspective view of the lithium primary battery of 3rd embodiment. The perspective view of the lithium primary battery of 4th embodiment. The perspective view of the lithium primary battery of 5th embodiment.

Claims (5)

A separator (9);
A positive electrode active material layer (4) disposed on one surface side of the separator (9);
A negative electrode active material layer (5) disposed on the other surface side of the separator (9);
A resin frame member (2, 3) surrounding the separator (9), the positive electrode active material layer (4) and the negative electrode active material layer (5);
A positive electrode current collector fixed to the frame member (2) so as to block one opening of the frame members (2, 3) and holding the positive electrode active material layer (4) between the separator (9) (6) and
A negative electrode current collector that is fixed to the frame member (3) so as to close the other opening of the frame member (2, 3) and holds the negative electrode active material layer (5) between the separator (9) (7)
The frame member (2, 3) includes a first portion (2a, 3a) for fixing the positive electrode current collector (6) and the negative electrode current collector (7), and the positive electrode current collector (6) or the negative electrode. Connected to the current collector (7), lead terminals (6t, 6T, 6B, 1T, 6T, 6T, 6T, 7t, 7T) and a second portion (2b, 3b) supporting the lead terminal (6t, 6T, 7t, 7T), and a thin battery (1A, 1B, 1C) , 1D, 1E). The lead terminals (6t, 6T, 7t, 7T) are a positive lead terminal (6t, 6T) connected to the positive current collector (6) and a negative lead connected to the negative current collector (7). Terminal (7t),
These positive electrode side lead terminals (6t, 6T) and negative electrode side lead terminals (7t) have strip-like shapes extending outwardly in the plane of the thin battery (1A, 1B, 1E) and are alternately positioned in plan view. Provided in
The positive electrode current collector (6) and the negative electrode current collector (7) are separated into one surface side and the other surface side by the first portion (2a, 3a) of the frame member (2, 3). The positive lead terminal (6t, 6T) and the negative lead terminal (7t) at the tip position of the second part (2b, 3b) of the frame member (2, 3) The thin battery according to claim 1, wherein at least one of the lead terminals (6t, 6T) and the negative electrode side lead terminal (7t) is exposed in the same plane by folding at least one of them to the opposite side. (1A, 1B, 1E).   Both of the positive electrode side lead terminal (6t) and the negative electrode side lead terminal (7t) are individually on opposite sides at the tip position of the second part (2b, 3b) of the frame member (2, 3). Folded, both the positive electrode side lead terminal (6t) and the negative electrode side lead terminal (7t) are exposed on both the first main surface side and the second main surface side of the thin battery (1A). Item 2. The thin battery (1A, 1E) according to item 2. An active material filling chamber (10) is formed between the positive electrode current collector (6) and the negative electrode current collector (7), and the separator (9) and the positive electrode active material are placed in the active material filling chamber (10). While accommodating the material layer (4) and the negative electrode active material layer (5), the positive electrode current collector (6) and the negative electrode current collector (7) are utilized as a substantial exterior material,
The lead terminals (6t, 6T, 7t, 7T) are made of metal integrally formed with the positive electrode current collector (6) or the negative electrode current collector (7) as an exterior material. The thin battery according to any one of (1A, 1B, 1C, 1D, 1E).   The lead terminal (6t, 6T, 7t, 7T) according to any one of claims 1 to 4, wherein the lead terminal (6t, 6T, 7t, 7T) is bonded to the second portion (2b, 3b) of the frame member (2, 3). Thin battery (1A, 1B, 1C, 1D, 1E).

Images