JP2004356461A - Electric double layer chip capacitor and chip electrolyte battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric double layer chip capacitor and a chip electrolyte battery which can be made into square shape as well as disc shape while preventing leakage of electrolyte or external intrusion of moisture. <P>SOLUTION: A positive electrode 42, a separator 44 and a negative electrode 46 are laid in layer and the positive electrode 42 and the negative electrode 46 are connected, respectively, with one end of a positive electrode terminal 20 and a negative electrode terminal 22 to produce a cell 40 which is contained in a housing 50 along with electrolyte and the other ends of the terminals 20 and 22 are extended outward through the wall 52 of the housing 50. In such an electric double layer chip capacitor, the housing 50 is formed of an insulating material and the positive electrode terminal 20 and/or the negative electrode terminal 22 has a bend 26 in the wall 52 of the housing 50. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a chip type electric double layer capacitor including an aqueous or non-aqueous electrolyte and an electrolyte battery.
[0002]
[Prior art]
A coin-type electric double layer capacitor is widely used as a backup power supply for electronic devices such as a mobile phone and a digital camera as a capacitor having a large capacity and having no influence on its life even when overcharged or overdischarged. The coin-type electric double-layer capacitor is one in which a cell in which a positive electrode, a separator, and a negative electrode are laminated is housed between an insulated positive electrode can and a negative electrode can, and sealed via a gasket. The cell is impregnated with an aqueous or non-aqueous electrolytic solution (for example, see Patent Document 1).
[0003]
In general, a rectangular area is set on an electronic component mounted on a circuit board as a mounting area on the circuit board. However, since the coin-type electric double-layer capacitor has a disk shape, a dead space in which other components cannot be arranged occurs in a rectangular region surrounding the capacitor, which hinders miniaturization of a circuit board.
[0004]
When the coin-type electric double layer capacitor has a square shape, the dead space can be reduced, and the mounting area can be effectively used. However, when the electrode can was formed in a square shape, there was a problem that sealing with a gasket became difficult.
[0005]
[Patent Document 1]
JP-A-8-64484
[Problems to be solved by the invention]
Therefore, it is conceivable to form the container of the electric double layer capacitor from an insulating resin, ceramics, or the like instead of a metal can.
In this case, the lead member and the current collector connected to the cell are drawn out of the container surrounding the cell. However, since the adhesion between the lead member or the current collector and the container is not high, there is a possibility that the electrolyte solution inside the container leaks out from between them, or that external moisture enters the inside of the container.
In particular, when a non-aqueous electrolytic solution is used, electrolysis occurs due to intrusion of moisture, and the performance is reduced.
The same problem as described above also occurs when a coin-type aqueous or non-aqueous electrolyte battery having the same structure as the coin-type electric double-layer capacitor is squared.
[0007]
An object of the present invention is to provide a chip-type electric double-layer capacitor and a chip-type electrolyte battery which can be formed not only in a disk shape but also in a square shape without leakage of electrolyte or intrusion of moisture from the outside. .
[0008]
[Means for Solving the Problems]
In order to solve the above problems, the chip-type electric double-layer capacitor of the present invention,
A cell in which a positive electrode, a separator, and a negative electrode are laminated, and a cell formed by connecting one end of a positive electrode terminal and one end of a negative electrode terminal to the positive electrode and the negative electrode, respectively, is housed in a housing together with an electrolytic solution, and the other end of the terminal penetrates a wall of the housing. In the chip type electric double layer capacitor extending to the outside,
The housing is formed of an insulating material,
The positive electrode terminal and / or the negative electrode terminal have a bent portion in a wall of the housing.
[0009]
It is preferable that the electrode terminal having the bent portion is subjected to a surface roughening treatment at a portion penetrating the wall of the housing.
[0010]
[Action and effect]
In the chip-type electric double layer capacitor of the present invention, by bending the positive electrode terminal and / or the negative electrode terminal in the wall of the housing, the path of the electrode terminal from the inside to the outside of the housing can be lengthened, and the path can be complicated. . As a result, leakage of the electrolyte and intrusion of moisture are prevented.
In addition, if a roughened surface portion is formed at a position where the electrode terminal comes into contact with the insulating material forming the housing, the roughened surface portion enhances the adhesion with the insulating material and further increases the insulating property. Since the contact area with the material can be increased, leakage of the electrolytic solution and intrusion of moisture can be prevented.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
<Chip type non-aqueous electric double layer capacitor>
FIGS. 1A and 1B are perspective views of a chip type electric double layer capacitor (10) of the present invention. The chip type electric double layer capacitor (10) has a rectangular parallelepiped housing (50) formed of an insulating material. Examples of the insulating material include insulating resins such as liquid crystal polymer (LCP), deformed polyamide and nylon resin, insulating thermoplastics such as polyethylene terephthalate (PBT), polypropylene (PP), and polyphenylene sulfide (PPS), ceramics, Glass and the like can be exemplified.
[0012]
The housing (50) is configured by combining a first half (54) and a second half (56). A cell (40) described later is accommodated inside the housing (50) together with the electrolytic solution. From the housing (50), electrode terminals (20) (20a) electrically connected to the positive electrode (42) and the negative electrode (44) of the cell (40) penetrate the wall (52) of the housing (50). Has been pulled out. FIG. 1A shows a state in which the positive electrode terminal (20) is drawn out, and FIG. 1B shows a state in which the negative electrode terminal (20a) is drawn out of the housing (50). I have.
[0013]
The positive electrode terminal (20) is electrically connected to the positive electrode (42) (described later), and the horizontal portion disposed in the space of the housing (50) serves as a positive current collector. In the case of, it is created by processing a plate material such as aluminum.
The negative electrode terminal (20a) is electrically connected to the negative electrode (46) (to be described later), and a horizontal portion disposed in the space of the housing (50) serves as a negative current collector. In the case of a multilayer capacitor, it is made by processing a plate material such as stainless steel.
[0014]
FIG. 2 is a cross-sectional view taken along line AA in FIG. The first half (54) and the second half (56) each have a rectangular parallelepiped recess formed in the center, and the recesses are aligned with each other to accommodate the cell (40) in the housing (50). A space is formed. In this space, one half may be formed in a plate shape.
The cell (40) has a positive electrode terminal (20), a positive electrode (42), a separator (44), and a negative electrode (46) from the first half (54) side when the first half (54) is on the lower side. And the negative electrode terminal (20a) are stacked in this order, the second half (56) is covered on the upper side of the negative electrode terminal (20a), and the electrolyte is injected into the space.
[0015]
For the positive electrode (42) and the negative electrode (46), a material obtained by molding activated carbon powder or activated carbon fiber into a sheet or block shape, or a carbon nanomaterial such as fullerene or carbon nanotube can be used. Activated carbon / carbon composite can also be used for the positive electrode (42).
As the separator (44), a glass fiber nonwoven fabric, pulp papermaking, a film formed of an insulating resin such as polytetrafluoroethylene (PTFE), or the like is used.
The electrolytic solution may be an electrolyte such as tri-ethyl-methyl-ammonium-tetra-fluoro-borate (Et ₃ MeNBF ₄ ) or tetra-ethyl-ammonium-tetra-fluoro-borate (Et ₄ NBF ₄ ). An electrolytic solution dissolved in is used. As aprotic organic solvents, use is made of bifunctional solvents such as carbonates, lactones, nitriles, amides, nitroalkanes, sulphones, sulphoxides, phosphates, dinitrile or ether nitriles. Specific examples thereof include propylene carbonate (PC), ethylene carbonate (EC), gamma-butyrolactone (GBL), sulfolane (SFL) and acetonitrile (AN). Further, an ionic liquid such as 1-methyl-3-methyl-imidazolium may be used.
[0016]
As shown in FIGS. 2 and 3, each of the positive electrode terminal (20) and the negative electrode terminal (20a) is connected to a conductive binder (not shown) on the positive electrode (42) and the negative electrode (44) of the cell (40). An electrode contact portion (24) electrically connected to the housing (50), a portion (25) extending from the electrode contact portion (24) and penetrating the wall (52) of the housing (50), and the housing (50), and a lead portion (28) that is bent along the outer periphery of the housing (50) and brazed to the circuit board.
[0017]
As shown in FIGS. 2 and 3, the electrode terminals (20) and (20a) have a bent portion (26) bent in a wall (52) of the housing (50). It is desirable to bend the electrode terminals (20) and (20a) a plurality of times at approximately 90 °, but the electrode terminals (20) and (20a) are drawn out from the internal space of the housing (50) through the wall (52) to the outside. If possible, the number of bends is not limited. Further, the bending angle is not limited to 90 °, and may be bent in an arc shape.
By bending the electrode terminals (20) (20a) in the wall (52) of the housing (50), the path of the electrode terminals (20) (20a) connecting the internal space of the housing (50) and the outside is linear. Therefore, it is possible to prevent the electrolyte solution from leaking and the invasion of moisture from the outside, because the structure can be complicated and the path can be lengthened.
[0018]
As shown in FIG. 2 and FIG. 3, a portion (25) where the electrode terminals (20) and (20 a) penetrate the wall (52) of the housing (50) is subjected to a surface roughening treatment to reduce the surface roughness. By making the surface rough, the adhesion between the insulating material of the housing (50) and the electrode terminals (20) (20a) is increased, and the contact area with the insulating material can be increased by the unevenness due to the roughening treatment. In addition, since the leakage of the electrolyte and the path through which moisture enters can be complicated, the leakage of the electrolyte and the invasion of moisture from the outside can be prevented as much as possible in combination with the bending process.
The surface roughness of the surface-roughened portion is 0.1 μm or more in terms of center line average roughness in order to enhance the adhesion with the insulating material forming the housing (50) such as resin, ceramics, and glass. It is desirable that the thickness be 10 μm or less. As shown in FIG. 3, the surface roughening treatment is most preferably performed only on the portion (25) penetrating the wall (52) of the housing (50). However, the electrode contact portion (24) and the lead portion (28) are preferably used. May be subjected to a roughening treatment. The surface roughening treatment is desirably performed on both the positive electrode terminal (20) and the negative electrode terminal (20a) (hereinafter, these terminals are collectively referred to as “electrode terminals” as necessary), but only one of them is performed. You may.
The surface roughening treatment can be performed by, for example, gently rubbing with a file or performing etching, plating, sandblasting, or the like. As shown in FIG. 3, the electrode terminals (20) and (20a) are very thin compared to the width, so that the upper and lower surfaces of the electrode terminals (20) and (20a) are roughened. In this case, the side surface need not be subjected to the surface roughening treatment. Of course, the side surface may be subjected to a roughening treatment.
[0019]
The electrode terminals (20) and (20a) are subjected to the above-mentioned bending and, if necessary, roughening treatment, and then molded to form a back surface of the electrode contact portion (24) of the electrode terminals (20) and (20a). And, the outer periphery of the electrode contact portion (24) is formed so as to be surrounded by an insulating material. The surface of the electrode contact portion (24) is exposed to ensure conductivity with the electrodes (42) and (46). As a result, a half body (54) (56) having a space for accommodating the cell (40) is obtained.
[0020]
One of the prepared halves (54) (56) (in the following description, the first half (54) accommodating the positive electrode terminal (20)) is positioned so that the space faces upward as shown in FIG. And a conductive adhesive is applied to the surface of the electrode contact portion (24), and the positive electrode (42) and the separator (44) cut to predetermined dimensions are sequentially laminated.
Next, a conductive adhesive is applied to the surface of the negative electrode (46) or the electrode contact portion (24) on the second half (56) side, and the negative electrode (46) is arranged in the second half (56). . Thereafter, the second half (56) is placed so that the space faces downward, and the peripheral portions of the first half (54) and the second half (56) are joined by ultrasonic welding or the like. It is desirable that the positive electrode (42), the separator (44) and the negative electrode (46) are previously impregnated with an electrolytic solution by vacuum filling.
Thereafter, the electrode terminals (20) (20a) protruding from the housing (50) are bent downward along the peripheral surface of the housing (50), so that a chip-type electric double layer capacitor (FIG. 1 and FIG. 2) is formed. 10) is completed.
[0021]
In the obtained chip-type electric double layer capacitor (10), as described above, the electrode terminal (20) (20a) is bent at the portion (25) passing through the housing (50). Routes that are prone to leaking liquid and water intrusion from the outside are not linear, which complicates the route and makes the route longer than in the case of a straight line. Intrusion is prevented. Further, by performing the bending process, the electrode terminals (20) (20a) are prevented from coming off or moving even when the lead portions (28) (28) of the electrode terminals (20) (20a) are bent. In addition, the performance of the chip type electric double layer capacitor (10) can be stabilized, and the yield can be improved.
In addition, when a part (25) through which the electrode terminals (20) and (20a) penetrate the housing (50) is subjected to a surface roughening treatment in addition to bending, the electrode terminals (20) and (20a) and the housing ( 50) The adhesiveness with the insulating material can be increased, the contact area with the insulating material can be increased by the unevenness of the rough surface portion (26), and furthermore, the leakage path of the electrolytic solution and the path through which moisture enters can be improved. Since it can be complicated, it is possible to effectively prevent leakage of the electrolytic solution and intrusion of moisture from the outside.
[0022]
In the above embodiment, in order to simplify the structure, the positive terminal (20) is formed using the material used for the positive current collector, and the negative terminal (20a) is formed using the material used for the negative current collector. ), A current collector may be interposed between the positive electrode terminal (20) and the positive electrode (42) or between the negative electrode terminal (20a) and the negative electrode (46). In this case, the current collector may be applied to each of the electrode terminals (20) and (20a) by plating, or a plate-shaped current collector may be formed with the electrode terminals (20) and (20a) and the positive electrode (42) or the negative electrode ( 46).
[0023]
<Chip type water-based electric double layer capacitor>
The present invention is also applicable to a chip type water-based electric double layer capacitor.
The structure and manufacturing method of the chip-type water-based electric double-layer capacitor are substantially the same as those of the above-mentioned chip-type non-aqueous electric double-layer capacitor except for the materials such as the electrolytic solution described below.
As the electrolytic solution, an aqueous solution such as H ₂ SO ₄ , KOH, and LiClO ₄ is used.
Examples of the current collector include conductive butyl rubber and conductive elastomer that are not metal materials.
Examples of the separator include a polypropylene sheet, a polyethylene porous film, and a glass fiber nonwoven fabric.
[0024]
<Chip type non-aqueous electrolyte battery>
The present invention can be applied to a chip type nonaqueous electrolyte battery.
The structure and manufacturing method of the chip-type electrolyte battery are substantially the same as those of the above-mentioned chip-type electric double-layer capacitor, except that some materials are different as described below.
In this case, the positive and negative electrodes of the non-aqueous electric double layer capacitor are replaced with a positive active material and a negative active material, respectively. Examples of the positive active material include those obtained by press-molding or sintering powders of lithium cobaltate, lithium manganate, lithium nickelate, and the like. As the negative active material, powder of a graphite-based carbon material or a coke-based carbon material is pressed. Molded or sintered ones can be exemplified.
In addition, an organic solvent in which a lithium salt is dissolved is used for the electrolytic solution. Examples of the lithium salt include LiBF ₄ , LiClO ₄ , LiPF ₆ , LiAsF ₆ , Li (CF ₃ O ₂ ) ₂ N, and LiC ₄ F ₉ SO _{3. As} an organic solvent, propylene carbonate, gamma-butyrolactone, or a chain thereof is used. A mixed solution with a carbonic acid ester can be exemplified. Examples of the chain carbonate include dimethyl carbonate (DMC, DEC) and ethyl methyl carbonate (EMC).
As the separator, a polymer porous film such as polyolefin, polyethylene, or polypropylene is used.
The positive current collector is formed of aluminum or the like, and the negative current collector is formed of copper or the like.
Note that the current collector can be omitted by forming the positive electrode terminal with aluminum or the like and the negative electrode terminal with copper or the like.
[0025]
<Chip type aqueous electrolyte battery>
The present invention can also be applied to a chip-type aqueous electrolyte battery.
In this case, the positive and negative electrodes of the non-aqueous electric double layer capacitor are replaced with a positive active material and a negative active material, respectively. For example, in the case of a lithium ion battery, as a positive active material, a material obtained by sintering or compression molding nickel oxide powder or pellets can be exemplified. As a negative active material, Mm-Ni-Co-Mn-Al (Mm is a rare earth element) Examples thereof include sintering or compression molding of (mixture) -based hydrogen storage alloy powder or pellets.
In addition, KOH or a polymer hydrogel electrolyte is used as the electrolyte.
As the separator, a polymer porous film such as sulfonated polypropylene is used.
Foamed nickel is used for the positive current collector and the negative current collector.
For the electrode terminals, copper, aluminum, nickel, or the like can be used.
[0026]
The description of the above embodiments is intended to explain the present invention, and should not be construed as limiting the invention described in the claims or reducing the scope thereof. The configuration of each part of the present invention is not limited to the above-described embodiment, and various modifications can be made within the technical scope described in the claims.
[0027]
In the above embodiment, the square-shaped chip-type electric double-layer capacitor and the chip-type electrolyte battery have been described. However, by making the housing into a circular dish shape and making the electrode contact portions of the electrode terminals circular, a disk-shaped chip-type is formed. Electric double layer capacitors can be made. Also, other shapes such as an ellipse can be created.
[Brief description of the drawings]
FIG. 1A is a perspective view of a chip-type electric double layer capacitor of the present invention as viewed from a side from which a positive terminal is drawn out, and FIG. 1B is a perspective view as viewed from a side from which a negative terminal is drawn out.
FIG. 2 is a cross-sectional view taken along line AA of FIG.
FIG. 3 is a perspective view of an electrode terminal.
FIG. 4 is an explanatory view showing an assembling process of the chip-type electric double layer capacitor.
[Explanation of symbols]
(10) Chip type electric double layer capacitor (20) Positive electrode terminal (20a) Negative electrode terminal (26) Bend (40) Cell (42) Positive electrode (44) Separator (46) Negative electrode (50) Housing (52) Wall surface

Claims (4)

A positive electrode (42), a separator (44), and a negative electrode (46) are stacked, and a positive electrode (42) and a negative electrode (46) are connected to one end of a positive electrode terminal (20) and one end of a negative electrode terminal (20a), respectively. 40) is housed in the housing (50) together with the electrolytic solution, and the other ends of the terminals (20) and (20a) extend outside through the wall (52) of the housing (50).
The housing (50) is formed of an insulating material,
The chip-type electric double layer, wherein the positive electrode terminal (20) and / or the negative electrode terminal (20a) has a bent portion (26) bent in a wall (52) of a housing (50). Capacitors. The roughening treatment is applied to a portion of the positive electrode terminal (20) and / or the negative electrode terminal (20a) having the bent portion (26) at a portion penetrating the wall (52) of the housing (50). 2. The chip-type electric double-layer capacitor according to 1. A cell formed by laminating a positive active material, a separator and a negative active material, and connecting one end of a positive electrode terminal and one end of a negative electrode terminal to the positive active material and the negative active material, respectively, is housed in a housing together with an electrolytic solution, and the other end of the terminal. Is a chip-type electrolyte battery that extends outside through the wall of the housing,
The housing is formed of an insulating material,
The positive electrode terminal and / or the negative electrode terminal have a bent portion bent in a wall of the housing, wherein the chip-type electrolyte battery is provided. 4. The chip-type electrolyte battery according to claim 3, wherein the positive electrode terminal and / or the negative electrode terminal having the bent portion are subjected to a surface roughening treatment at a portion penetrating a wall of the housing. 5.

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