JP2003208886A - Battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery improved in the impact resistant performance in a connection part between a lead and a circuit board and possible to connect the lead and the circuit board to each other without giving a thermal influence to a battery main body. <P>SOLUTION: This battery has a metal plate-like lead 2 separately and electrically connected to each of a positive and a negative electrode and the circuit board 3, and the plate-like lead and the circuit board are connected to each other by a rivet 4. Desirably, a battery element is interposed between the wrapping material, and both the peripheral edges of the wrapping material are sealed by thermal welding to seal the battery element. The metal plate-like lead separately and electrically connected to each of the positive and the negative electrodes is projected from the wrapping material through the sealing part of the wrapping material, and the circuit board is provided on the thermal welding part of the wrapping material near the part, through which the plate- like lead passes. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to batteries.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for miniaturization of mobile devices such as mobile phones and mobile terminals. However, in the mobile devices, the size and weight of the battery is large, and the size of the mobile device is small. It can be said that miniaturization of the battery means that the battery is downsized. Against this background, thin film type batteries having high energy density and excellent in lightness have recently attracted attention, and examples of such thin film type batteries include secondary batteries such as lithium batteries. It has been put to practical use.

In such a lithium battery, when overcharged above a predetermined battery voltage, deposition of lithium metal on the negative electrode, decomposition of the positive electrode active material, decomposition of the organic electrolytic solution, etc. occur,
This may lead to short circuit between the positive and negative electrodes and deterioration of battery performance. On the other hand, when the lithium battery is over-discharged below a predetermined battery voltage, the metal of the negative electrode current collector is ionized and eluted in the organic electrolytic solution, resulting in deterioration of the current collecting function and decrease in capacity due to falling of the negative electrode active material. There is a risk.

Therefore, in order to prevent such overcharge and overdischarge of the lithium battery, the battery incorporates a printed conductor board (circuit board) on which a protection circuit is mounted. As such a battery, for example, a battery in which a circuit board and a secondary battery are housed in a mold housing made of resin or the like is known. In this battery, the printed circuit board (circuit board) on which the protection circuit is mounted is placed on the side of the secondary battery and housed in the mold housing, and the discharge terminal, charging terminal and common terminal are provided in the mold housing. The positive electrode terminal and the negative electrode terminal of the secondary battery, the protection circuit, the discharge terminal, the charging terminal and the common terminal are connected by soldering or ultrasonic welding using a plurality of tabs.

However, the joining by soldering or ultrasonic welding has a relatively low joining strength. Therefore, in the above-mentioned technique, a shock (for example, a shock caused by a drop of a portable device to which the battery is attached) is applied to the battery. At times, there is a problem in that the bonding is broken and the connection between the leads and the circuit board side is easily broken. In addition, when soldering, there is a possibility that the battery body side is affected by heat and the battery performance is degraded.

[0006]

DISCLOSURE OF THE INVENTION The present invention improves impact resistance at a connecting portion between a lead and a circuit board, and enables the lead and the circuit board to be connected without affecting the battery body by heat. The purpose is to provide a battery.

[0007]

Means for Solving the Problems The inventors of the present invention have diligently studied to solve the above-mentioned problems, and as a result, by connecting using a rivet instead of solder, the impact resistance at the connecting portion between the lead and the circuit board is improved. The inventors have found that the properties can be improved, and that the rivet can connect the conducting wire to the battery without affecting the battery body with heat, and thus completed the present invention. That is, the gist of the present invention lies in the following (1) to (6).

(1) A flat plate lead and a circuit board made of metal, which are electrically connected to the positive electrode and the negative electrode independently of each other, are provided, and the flat lead and the circuit board are connected by rivets. And the battery. (2) The battery element is interposed between the exterior materials, the peripheral edges of the exterior material are sealed by heat fusion to seal the battery element, and the positive electrode and the negative electrode are electrically coupled independently of each other. The metal-made flat plate lead penetrates the sealing part of the exterior material and is exposed to the outside of the exterior material, and the circuit board is installed on the heat-sealing portion of the exterior material on the side where the flat lead penetrates. The battery according to (1) above.

(3) The battery according to (1) or (2) above, which has a connector with wiring, and the wiring of the connector with wiring is soldered onto a circuit board. (4) The battery according to (1) or (2) above, wherein the connector is soldered on the circuit board. (5) An electric device equipped with the battery according to any one of (1) to (4) above.

(6) A mobile phone equipped with the battery according to any one of (1) to (4) above.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 to 12 are views showing a battery connection structure as one embodiment of the present invention.
As the present embodiment, the battery connection structure of the present invention,
An example applied to a battery pack of a flat plate type lithium secondary battery will be described.

As shown in FIG. 1, the battery of the present invention has a metal-made flat lead 2 and a circuit board 3 which are electrically coupled to the positive electrode and the negative electrode of the battery body 1 independently of each other.
The flat lead 2 and the circuit board 3 are joined by a rivet 4. Although not shown in the figure, a secondary battery protection circuit is mounted on the circuit board 3. The battery body 1 includes a battery element 5 and an exterior material (housing) 6 as will be described later.
And the battery element 5 is hermetically sealed by sealing the peripheral portions of the outer packaging material 6 by heat fusion.
A metal flat lead (pole terminal) 2 electrically connected independently to each of the positive electrode and the negative electrode of the battery element 5 penetrates the sealing portion 7 of the outer package 6 and is exposed to the outside of the outer package. .

As shown in FIG. 2A, the flat lead 2
A through hole for inserting the rivet 4 (hereinafter,
8 is also provided. Similarly, the circuit board 3 is provided with holes 9 in advance, and the flat leads 2 and the circuit board 4 are overlapped with each other by aligning these holes 8 and 9. Then, the rivet 4 is inserted into these holes 8 and 9, and as shown in FIG.
By crimping the tip of B, the flat lead 3 and the circuit board 4 are connected. At this time, the flat lead 3 is electrically connected to the printed conductor on the circuit board 3. Although it is preferable to insert the rivet from the side of the flat lead 3 as shown in FIG. 2, the rivet may be inserted from the side of the circuit board. Here, as the rivet 4, a rivet having a round head portion 4A and a hollow shaft portion 4B is used, but the shape of the rivet is not limited to this.
For example, a flat head 4 as shown in FIG.
It may be provided with A ', or a solid-shaped shaft portion 4B'
It can be provided with.

In this way, the flat lead 2 is provided with the rivet 4
Since it is firmly connected to the circuit board 3 by this, the shock resistance of the battery having the protection circuit as shown in FIG. 1 can be made extremely high. As the material of the rivet 4, nickel (Ni), copper (Cu), aluminum (Al), brass, phosphor bronze, zinc (Zn) plated titanium or titanium (Ti) plated iron or the like is used.

As shown in FIGS. 5A and 5B, a single or a plurality of protrusions 4C (here, the protrusions 4C are provided on the back surface of the head portion 4A of the rivet 4 (the surface contacting the flat lead 2 or the circuit board 3). 3) may be provided to prevent the rivet 4 from rotating. In other words, when the flat lead 2 and the circuit board 3 are connected by the rivet 4, the protrusion 4C bites into the flat lead 2 or the circuit board 3, thereby preventing the rivet 4 from rotating.

Alternatively, as shown in FIGS. 6A and 6B, grooves 4D and 4E may be provided on the back surface of the head portion 4A to prevent the rivet from rotating. In FIG. 6A, an annular groove portion 4D formed concentrically with the shaft portion 4B is provided, and in FIG. 6B, the shaft portion 4B.
A groove portion 4E having a cross shape is provided around the axis center of.
By providing such groove portions 4D and 4E, the contact area between the head portion 4A and the flat lead 2 or the circuit board 3 is reduced, whereby the head portion 4A and the flat lead 2 are formed.
It is possible to prevent the rivet 4 from rotating with respect to the flat lead 2 and the circuit board 3 by strengthening the contact pressure with the circuit board 3 and the circuit board 3.

Generally, aluminum, copper, nickel, SUS or the like can be used as the material of the flat lead 2. The preferred material for the positive electrode lead is aluminum. Further, preferred materials for the negative electrode lead are copper and nickel, and particularly preferred is copper. The battery of the present invention preferably has a connector 10. As an example thereof, as shown in FIG. 6A, the connector is a connector with wiring 10, and wiring 11 of the connector with wiring is a circuit board. Soldered on top of FIG. 3, FIG. 6 (B)
As shown in FIG. 3, the connector 11 is directly soldered on the circuit board 3. Since the connector 10 is lighter in weight than a battery or a circuit board, sufficient strength can be secured by soldering. Further, since the battery body is connected via the flat lead 2 and the circuit board 3, most of the heat generated at the time of soldering does not reach the battery body, which may adversely affect the battery body 1. Not even give.

In the present invention, in terms of space efficiency, as shown in FIG. 12, the circuit board is installed on the heat-sealed portion of the exterior material on the side 21 through which the flat lead 2 penetrates. It is preferable. At this time, the flat lead 2 may be zigzag folded and sandwiched between the circuit board and the battery body. An example of the battery body 1 is a battery body in which a battery element 5 (see FIG. 9) is housed inside an exterior material 6 as shown in FIG. 7, and the exterior material 6 is a battery element. After housing 5, the outer edge portions 12 and 12 are sealed and formed. In addition, the flat lead 2 penetrates the sealing portion 7 of the exterior material 6 from the exterior material 6 and is exposed to the outside of the exterior material. Although only the plate-shaped lead 2 and the tab 13 on one pole side are shown in FIG. 9 (only the positive electrode side in FIG. 9), one end of each of the plate-shaped leads 4 of the positive electrode and the negative electrode is inside the exterior material 2. The tabs 13 (the tab 13 will be described later) are respectively joined to the coupling terminals configured by bundling, and the other end is electrically connected to the circuit board 4 outside the exterior material 2 as described above. It is like this. Each flat lead 2 is made of the same material as the tab 13 so as not to cause electrolytic corrosion. Here, the flat lead and the tab on the positive electrode side are made of an aluminum material, and the flat lead on the negative electrode side is made. The lead and the tab B are made of a copper material.

The battery element 5 is formed by laminating a plurality of flat unit battery elements 14 (here, three), as shown in FIG. 9, in order to increase the capacity of the battery. Each unit battery element 14 includes a positive electrode 14A, a negative electrode 14B, a positive electrode 14A and a negative electrode 1
4B, and an electrolyte layer 14C interposed between the 4C and 4B. In addition, in the unit battery element 14, in FIG.
A positive posture in which the positive electrode 14A is on the upper side and the negative electrode 14B is on the lower side, and conversely, the negative electrode 14B is on the upper side
There is a reverse posture with A as the lower side.

In the battery element 5, the unit battery elements 14 having different postures are alternately stacked so that the unit battery elements 14, 14 adjacent in the stacking direction have the same polarity (that is, the positive electrode 14A and the positive electrode 14A). 14A, or the negative electrode 14B and the negative electrode 14B) are in contact with each other. In addition, as described above, the positive electrode 14A has a tab 1 made of aluminum.
3A, and the negative electrode 14B is provided with a tab 13B made of copper. The tab 13A is formed by extending a current collector 15A constituting a positive electrode 14A as described later with reference to FIG. 11, and the tab 13B is a current collector 1 constituting a negative electrode 14B.
5B is extended and formed, and current collectors 15A, 15
The material of B, and by extension, the tabs 13A and 13B, is determined based on the compatibility with the positive electrode active material 16A and the negative electrode active material 16B described later.

The battery body 1 has a structure in which a plurality of stacked unit battery elements 14 are connected in parallel, and therefore, the stacked unit battery elements 14 are arranged as shown in FIG. In order to easily polymerize and bind the tabs 13A on the positive electrode side to each other, similarly, to easily polymerize and bind the tabs 13B on the negative electrode side of each of the stacked unit battery elements 14, in which unit Also in the battery element 14, each unit battery element 14 is formed so that each positive electrode tab 13 is aligned with one side and each negative electrode tab 13B is aligned with the other side.

Therefore, as described above, the unit battery element 1
4 includes those stacked in the forward posture and those stacked in the reverse posture, and those stacked in the forward posture are the positive electrode 14A.
With the negative electrode 14B facing downward and the tabs 13A and 13B facing upward when viewed from above, the positive electrode side tab 13A
On the right side (therefore, this unit battery element 14 is referred to as a light type (hereinafter abbreviated as R type) or R type unit battery element 14), while
In the case of stacking in an inverted posture, the tabs 13A, 1 are viewed in a top view with the positive electrode 14A facing upward and the negative electrode 14B facing downward.
3B is formed so that the positive electrode side tab 13A is on the left side (therefore, this unit battery element 14 is referred to as a left type (hereinafter abbreviated as L type) or L type unit battery element 14). ]. In the R type and the L type, the tab 13A for the positive electrode and the tab 13 for the negative electrode
The arrangement with B has a structure symmetrical with respect to the center line CL.

With such a structure, as described above, when these unit battery elements 14 are stacked upside down (in the thickness direction) (ie, R
The positive electrode is on the top and the L type is on the negative electrode, or the R type is on the negative electrode and the L type is on the positive electrode), the positive electrode tab 13A and the negative electrode tab 13B are Each is concentrated on one side so that they can be easily bound together.

Now, the exterior material 6, the positive electrode 14A, the negative electrode 14B and the electrolyte layer 14C will be described below. First, the exterior material 6 will be described. The exterior material 6 may have any structure as long as it has mechanical strength and sealing ability. In addition to the configuration shown in FIG. Alternatively, an exterior material as shown in FIG. 8 may be used. In the exterior material of FIG. 8, a sheet-shaped housing member is partially drawn to form a housing portion 17 for housing the battery element 5. After housing the battery element 5 in the housing portion 17, the housing member is formed. Are folded back, overlapped and sealed.

As shown in FIGS. 7 and 8, it is preferable to seal the laminated outer packaging materials 6 in terms of ease of manufacture and battery performance such as battery capacity. In this case, the flat lead 2 can be easily exposed to the outside from the sealing portion of the exterior material 6. Exposing the flat lead 2 from the sealing portion 7 of the exterior material 6 facilitates electrical connection with the battery element 5 housed inside, and as a result, improves yield and safety of the battery. This is the preferred embodiment.

Further, it is preferable that the exterior material 6 has shape variability because it is easy to change the shape of the battery in various ways. Further, when the battery element 5 is housed in the exterior material 6 and the outer edge portion of the exterior material 6 is sealed, it is preferable that the inside of the exterior material 6 is in a vacuum state before such sealing. As a result, a pressing force can be applied to the battery element 5, and battery characteristics such as cycle characteristics can be improved.

As the material of the exterior material 6, a metal such as aluminum, nickel-plated iron, copper or the like or a synthetic resin can be used. However, since it is lightweight, has high moisture resistance and is easy to process, it is not a metal. It is preferable to use a flexible film-shaped composite material [for example, a laminated composite material (laminate film)] in which synthetic resins are laminated. By using the laminated composite material, it is possible to reduce the thickness and weight of the member forming the exterior material 6, and to improve the capacity of the battery as a whole.

A laminated composite material is shown in FIG.
As shown in (A), a laminate of a metal layer 18 and a synthetic resin layer 19 can be used. This metal layer 18
Is for preventing the infiltration of water or maintaining the shape retention property, and is a simple metal such as aluminum, iron, copper, nickel, titanium, molybdenum and gold, an alloy such as stainless steel and hastelloy, or a metal oxide such as aluminum oxide. Although it may be a material, aluminum having excellent workability is particularly preferable. The metal layer 18 can be formed by a metal foil, a metal vapor deposition film, a metal sputter, or the like.

The synthetic resin 19 is used for the metal layer 18 and the battery element 5.
It is used to prevent contact with the like or to protect the metal layer 18, and the elastic modulus and tensile elongation are not particularly limited, and include those generally called elastomers. As the synthetic resin 19, thermoplastics, thermoplastic elastomers, thermosetting resins and plastic alloys are used. These resins include those in which a filler such as a filler is mixed.

The laminated composite material is shown in FIG.
As shown in (B), a synthetic resin layer 19A that functions as an outer protective layer on the outer surface of the metal layer 18, and corrosion of the electrolyte on the inner surface and contact between the metal layer 18 and the battery element 5 are prevented, and a metal layer A three-layer structure in which a synthetic resin layer 19B functioning as an inner protective layer for protecting 18 is laminated is also possible.

In this case, the resin 18 used for the outer protective layer
For A, it is desirable to use a resin having excellent chemical resistance and mechanical strength such as polyethylene, polypropylene, modified polyolefin, ionomer, amorphous polyolefin, polyethylene terephthalate, and polyamide. On the other hand, as the resin 6B used for the inner protective layer, a chemically resistant synthetic resin is used, and for example, polyethylene, polypropylene, modified polyolefin, ionomer, ethylene-vinyl acetate copolymer or the like can be used.

The laminated composite material is shown in FIG.
As shown in (C), an adhesive 20 may be interposed between each of the metal layer 18, the protective layer forming synthetic resin 19A, and the inner protective layer synthetic resin layer 19B. Furthermore, in order to bond the connecting portion (sealing portion) of the housing member, an adhesive layer made of a resin such as polyethylene or polypropylene that can be welded can be provided on the innermost surface of the composite material.

The exterior material 6 may be formed by fusing the periphery of the film-like body, or the sheet-like body may be drawn by vacuum forming, pressure forming, press forming or the like. It can also be molded by injection molding a synthetic resin. In the case of injection molding, the metal layer is usually formed by sputtering or the like. Next, the positive electrode 14A and the negative electrode 14B will be described with reference to FIG. 11. The positive electrode 14A uses the positive electrode current collector 15A as a core material, and the positive electrode active material 1 is provided on one surface of the positive electrode current collector 15A.
6A is coated to form a negative electrode 14B.
Uses the negative electrode current collector 15B as a core material.
One side of B is coated with the negative electrode active material 16B. In addition, from each positive electrode collector 15A, the positive electrode tab 13
A is extended, and similarly, a negative electrode tab 13B is extended from each negative electrode current collector 15B.

The active materials 16A and 16B may be coated on both surfaces of the current collectors 15A and 15B, respectively. As the current collectors 15A and 15B, a foil made of metal is generally used. Here, the active material 16 is used.
Due to the compatibility with A and 16B, the positive electrode current collector 15A (tab 13
Aluminum is included as A), and the negative electrode current collector 15B is used.
Copper is used as each (including the tab 13B). The thickness of the current collectors 15A and 15B is appropriately selected, but if it is too thin, the mechanical strength becomes weak and processing becomes difficult, leading to a decrease in productivity. Since there is a risk of lowering the energy density as a whole, it is preferably in the range of 1 to 30 μm.

The current collectors 15A and 15B and the active material 16
In order to increase the adhesive strength with A and 16B, the active material 16A,
Before coating 16B, current collectors 15A, 15B
It is preferable to preliminarily roughen the surface of the above. As such a surface roughening method, for example, a mechanical polishing method,
There are electrolytic polishing method, chemical polishing method and the like. Examples of the mechanical polishing method include a method of polishing the surface of the current collector with a wire brush provided with abrasive cloth paper to which abrasive particles are fixed, a grindstone, an emery buff, a steel wire and the like. In addition, each current collector 15
A and 15B are composed of a plate member, a mesh member, punching metal, or the like.

As the positive electrode active material 16A, an inorganic compound or an organic compound can be used as long as it can store and release lithium ions. As an inorganic compound, a transition metal oxide,
Examples thereof include complex oxides of lithium and a transition metal, chalcogen compounds such as transition metal sulfides, and the like. Here, Fe, Co, Ni, Mn or the like is used as the transition metal. Specifically, transition metal oxides such as MnO, V ₂ O ₅ , V _{60 13} and TiO ₂ , composite oxides of lithium and transition metals such as lithium nickel oxide, lithium cobalt oxide and lithium manganate, and TiS. ₂ , transition metal sulfides such as FeS, MoS ₂ and the like can be mentioned. These compounds may be partially element-substituted to improve their properties. Examples of the organic compound include polyaniline, polypyrrole, polyacene, disulfide compounds, polysulfide compounds and the like. As the positive electrode active material 16A,
You may mix and use these inorganic compounds and organic compounds. Preferred is a composite oxide of at least one transition metal selected from the group consisting of cobalt, nickel and manganese and lithium.

The particle size of the positive electrode active material 16A may be appropriately selected in consideration of the other constituent elements of the battery, but it is usually 1 to 100 μm, particularly 2 to 60 μm for initial efficiency and cycle characteristics. It is preferable because the battery characteristics such as are improved. As the negative electrode active material 16B, a carbon-based material such as graphite or coke, which can store and release lithium ions, is usually used. Such a carbon-based substance can also be used in the form of a mixture with a metal, a metal salt, an oxide, or the like, or a coating. Further, as the negative electrode material,
Oxides and sulfates of silicon, tin, zinc, manganese, iron, nickel, etc., metallic lithium, Li-A1, Li-Bi-C
Lithium alloys such as d and Li-Sn-Cd, lithium transition metal nitrides, and silicon can also be used. From the viewpoint of capacity, graphite or coke is preferable.

If the particle size of the negative electrode active material 16B is too large, the electron conductivity deteriorates, and from the viewpoint of improving the battery characteristics such as initial efficiency, rate characteristics, cycle characteristics, etc., the average particle diameter of the negative electrode active material 16B is the upper limit. Is usually 12 μm or less, preferably 10 μm or less, and the lower limit is usually 0.5 μm or more, preferably 7 μm or more. The positive electrode active material 16A and the negative electrode active material 16B are bonded to the current collectors 15A and 15B, respectively, and in order to bind the polar active materials to each other, the positive electrode active material 16A and the negative electrode active material 16B. It is preferable to mix a binder with the above.
As the binder, inorganic compounds such as silicate and glass, and various resins mainly composed of polymer can be used. Examples of the resin include alkane-based polymers such as polyethylene, polypropylene and poly-1,1-dimethylethylene; unsaturated polymers such as polybutadiene and polyisoprene; polystyrene, polymethylstyrene,
Polymers having a ring such as polyvinyl pyridine and poly-N-vinyl pyrrolidone; polymethyl methacrylate, polyethyl methacrylate, polybutyl methacrylate, polymethyl acrylate, polyethyl acrylate, polyacrylic acid, polymethacrylic acid, poly Acrylic polymers such as acrylamide; Fluorine resins such as polyvinyl fluoride, polyvinylidene fluoride, polytetrafluoroethylene;
CN group-containing polymers such as polyacrylonitrile and polyvinylidene cyanide; polyvinyl alcohol-based polymers such as polyvinyl acetate and polyvinyl alcohol; halogen-containing polymers such as polyvinyl chloride and polyvinylidene chloride; electrically conductive polymers such as polyaniline . Also, a mixture of the above polymers, a modified product, a derivative, a random copolymer, an alternating copolymer, a graft copolymer, a block copolymer and the like can be used.

If the amount of the binder is too small, the strength of the electrode may be lowered. On the other hand, if the amount of the binder is too large, the capacity may be lowered or the rate characteristics may be lowered, so that the active material 100 may be deteriorated. The blending amount of the binder with respect to parts by weight is preferably 0.1 to 30 parts by weight, and 1 to 15 parts by weight.
More preferably, the amount is parts by weight. In addition, the active material 16A,
16B may contain, if necessary, an additive such as a conductive material and a reinforcing material for expressing various functions, a powder or a filler. The conductive material is not particularly limited as long as it can impart conductivity by mixing an appropriate amount with the active materials 16A and 16B, but is usually carbon powder such as acetylene black, carbon black or graphite, or fibers of various metals. ,
Examples include foil. As additives, trifluoropropylene carbonate, vinylene carbonate, 1,6-
Dioxaspiro [4,4] nonane-2,7
-Dione, 12-crown-4-ether and the like can be used to improve the stability and life of the battery. As the reinforcing material, various inorganic or organic spherical or fibrous fillers can be used.

The active materials 16A and 16B are connected to current collectors 15A and 1
As a method for forming on 5B, for example, powdery active materials 16A and 16B are mixed with a binder together with a solvent, and this is dispersed into a coating material using a ball mill, a sand mill, a twin-screw kneader, or the like. There is a method of coating on the current collectors 15A and 15B and drying. In this case, the type of solvent used is not particularly limited as long as it is inert to the active materials 16A and 16B and can dissolve the binder,
Any commonly used inorganic or organic solvent such as N-methylpyrrolidone can be used.

The active material 16A, 16B is mixed with a binder and heated to be softened, and then the current collector 1
The layers of the active materials 16A and 16B can be formed on the current collectors 15A and 15B by pressure bonding or spraying on the 5A and 15B. Alternatively, without mixing the binder, the active materials 16A and 16B are used as the current collector 15A,
By firing on 15B, current collectors 15A, 15A
A layer of active materials 16A and 16B can also be formed on B.

The active materials 16A and 16B are made of the same material (electrolyte) as the material of the electrolyte layer 14C described later in order to facilitate the movement of ions within the active materials 16A and 16B.
Are mixed. The greater the amount of the electrolytic substance mixed, the easier the migration of ions in the active materials 16A and 16B, which is preferable in terms of rate characteristics. On the other hand, the smaller the amount of the electrolytic substance, the higher the energy density. Therefore, the mixing ratio of the electrolytic material to the active materials 16A and 16B is 10 to 10.
It is preferably 50% by volume.

The film thickness of each active material 16A, 16B is
A thicker one is preferable in terms of capacitance, while a thinner one is preferable in terms of rate characteristics. Therefore, the film thickness of each active material 16A, 16B has a lower limit of usually 20 μm or more, preferably 30 μm or more.
μm or more, more preferably 50 μm or more, most preferably 80 μm or more, while the upper limit is usually 2
The thickness is 00 μm or less, preferably 150 μm or less.

Now, the electrolyte layer 14C will be described. The electrolyte layer 14C is the positive electrode 14A as described above.
Is interposed between the negative electrode 14B and the negative electrode 14B, and is formed by impregnating a porous sheet with an electrolyte to be described later, and the thickness of the electrolyte layer 14C is usually 1 to 200 μm, preferably 5 μm.
˜50 μm. As the porous sheet, one having a porosity of 10 to 95% is usually used, but the porosity is 30.
It is preferable to use about 85%. In addition, as the material of the porous sheet, a porous material using polyolefin or polyolefin in which some or all of hydrogen atoms are fluorine-substituted (specifically, a microporous membrane formed using a synthetic resin such as polyolefin) is used. Membranes, non-woven fabrics, woven fabrics, etc. are used. Also, regarding the thickness of the porous sheet,
Usually, one having a thickness of 1 to 200 μm, preferably 5 μm to 50 μm is used.

As the electrolyte with which the porous sheet is impregnated, various electrolytes such as a fluid electrolyte (hereinafter referred to as an electrolyte solution) and a non-fluid electrolyte such as a gel electrolyte or a completely solid electrolyte are used. It From the viewpoint of battery characteristics, it is preferable to use an electrolytic solution or a gel electrolyte, and for safety, it is preferable to use a non-fluidic electrolyte. In particular, when a non-fluidic electrolyte is used, liquid leakage can be prevented more effectively with respect to a battery using a conventional electrolytic solution. Therefore, as described above, the exterior material that houses the battery element 5 including the electrolyte layer 14C. As the material of No. 6, it is possible to use a material such as a laminated film having a low strength but a thin shape and a variable shape.

Such an electrolyte solution, gel electrolyte and complete
The solid electrolyte will be described. First, the electrolyte layer 14C
The applicable electrolyte solution is described below.
It is usually produced by dissolving the supporting electrolyte in a non-aqueous solvent.
As the supporting electrolyte, a positive electrode active material 16A and an electrolyte are used.
And stable to the negative electrode active material 16B, and
The ions are charged with the positive electrode active material 16A or the negative electrode active material 16B.
It is a non-aqueous substance that can move to perform a chemical reaction.
Any of them can be used. concrete
Is LiPF₆, LiAsF₆, LiSbF₆, LiB
F_Four, LiClO _Four, LiI, LiBr, LiCl, Li
AlCl, LiHF₂, LiSCN, LiS0₃CF₂etc
Lithium salts of can be used. Of these
Especially LiPF₆, LiClO_FourI prefer to use
Yes.

When a non-aqueous solvent is used as a solvent for these supporting electrolytes, the concentration is generally 0.5 to 2.5 m.
An electrolyte solution with a concentration of ol / L is used. The non-aqueous solvent that dissolves these supporting electrolytes is not particularly limited,
It is preferable to use a solvent having a relatively high dielectric constant. Specifically, cyclic carbonates such as ethylene carbonate and propylene carbonate, acyclic carbonates such as dimethyl carbonate, diethyl carbonate and ethylmethyl carbonate, glymes such as tetrahydrofuran, 21-methyltetrahydrofuran and dimethoxyethane, γ
-Lactones such as butyrolactone, sulfur compounds such as sulfolane, and nitriles such as acetonitrile are used. These solvents can be used alone or in a mixture of two or more kinds.

In particular, any one of cyclic carbonates such as ethylene carbonate and propylene carbonate and non-cyclic carbonates such as dimethyl carbonate, diethyl carbonate and ethylmethyl carbonate is used, or any one of them is used. It is preferable to use a mixture of two or more kinds. Further, those in which a part of hydrogen atoms in the molecule of these solvents are replaced with halogen or the like can be used.

Additives may be added to these solvents. Examples of the additive include trifluoropropylene carbonate, vinylene carbonate, 1,6-
Dioxaspiro [4,4] nonane-2,7
-Dione, 12-crown-4-ether, etc.
It can be used for the purpose of improving battery stability, performance and life.

Next, the gel electrolyte applicable to the electrolyte layer 14C will be described. The gel electrolyte is usually produced by holding the above electrolytic solution with a polymer. That is, the gel electrolyte is usually one in which the electrolytic solution is retained in the polymer network and the fluidity as a whole is significantly reduced. In such a gel electrolyte, although it has characteristics such as ionic conductivity similar to those of the above-mentioned electrolyte solution, the fluidity and volatility are remarkably suppressed and the safety is enhanced. If the ratio of the polymer in the gel electrolyte is too low, it may not be possible to hold the electrolytic solution and liquid leakage may occur.On the other hand, if it is too high, the ionic conductivity may decrease and the battery characteristics may deteriorate. , 1
It is preferably in the range of 50% by weight.

The polymer used in the gel electrolyte is not particularly limited as long as it is a polymer capable of forming a gel with an electrolytic solution, and those produced by polycondensation of polyester, polyamide, polycarbonate, polyimide and the like. , Polyurethane, polyurea, etc., which are produced by polyaddition, polymethylmethacrylate, etc., acrylic derivative polymers, polyvinyl acetate, polyvinyl chloride, polyvinylidene fluoride, etc. There are things to be done.

Examples of preferable polymers include polyacrylonitrile and polyvinylidene fluoride.
Here, the polyvinylidene fluoride includes not only a vinylidene fluoride homopolymer but also a copolymer with another monomer component such as hexafluoropropylene. Further, acrylic acid, methyl acrylate, ethyl acrylate, ethoxyethyl acrylate, methoxyethyl acrylate, ethoxyethoxyethyl acrylate, polyethylene glycol monoacrylate, ethoxyethyl methacrylate, methoxyethyl methacrylate, ethoxyethoxyethyl methacrylate, polyethylene glycol monomethacrylate, N , N-diethylaminoethyl acrylate, N, N-dimethylaminoethyl acrylate, glycidyl acrylate, allyl acrylate, acrylonitrile, N-vinylpyrrolidone, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, Diethylene glycol Dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, it is also preferable to use an acrylic polymer obtained by polymerizing an acrylic derivative type, such as polyethylene glycol dimethacrylate.

If the weight average molecular weight of the polymer / concentration of the polymer with respect to the electrolytic solution is too low, the retention of the electrolytic solution is lowered (making it difficult to form a gel) and the electrolyte flows to cause the electrolyte 6 to flow from the exterior material 6. There is a risk of leakage to the outside (liquid leakage), while
If it is too high, the viscosity becomes excessively high, which causes difficulty in the manufacturing process, or the proportion of the electrolytic solution is low, so that the ionic conductivity is low and the battery characteristics (for example, rate characteristics) may be deteriorated. Therefore, the weight average molecular weight is usually 10,0
It is preferable to use a polymer in the range of 00 to 5,000,000, and the concentration of the polymer in the electrolytic solution is preferably in the range of 0.1% by weight to 30% by weight.

Next, the completely solid electrolyte applicable to the electrolyte layer 14C will be described. As the completely solid electrolyte, various solid electrolytes known so far can be used. For example, it can be formed by mixing the polymer used in the gel electrolyte and the supporting electrolyte salt in an appropriate ratio. In this case, in order to increase the conductivity, it is preferable that the polymer has a high polarity and has a skeleton having a large number of side chains.

Since the battery as one embodiment of the present invention is constructed as described above, it has the following advantages.
That is, since the flat lead 2 and the circuit board 3 are connected by the rivet 4, there is an advantage that the impact resistance (mechanical reliability) at the connecting portion between the lead and the circuit board can be improved.

Further, since no heat is used in the rivet processing, there is an advantage that deterioration of the battery main body 1 due to the influence of heat can be prevented. The battery of the present invention is not limited to the above-mentioned embodiment and can be variously modified without departing from the spirit of the invention. For example, in the above-described embodiment, each unit battery element 14 is formed in a quadrangular shape, but the shape of the unit battery element 14 is appropriately set according to design conditions. Of course, it may be circular.

Further, the battery of the present invention can be applied not only to a lithium battery using lithium ions as an electromotive substance but also to various batteries using other substances as electromotive substances.

[0058]

As described above in detail, according to the present invention, the shock resistance at the connecting portion between the lead and the circuit board can be improved, and the lead and the circuit board can be connected to each other without affecting the battery body by heat. The battery can be provided.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a structure of a battery as an embodiment of the present invention.

FIG. 2 is a diagram showing a battery connection structure as one embodiment of the present invention, (A) is a schematic perspective view showing enlarged structures of a rivet, a flat lead and a circuit board, and (B) is a diagram. It is a typical side view which expands and shows the structure of a rivet, a tabular lead, and a circuit board.

FIG. 3 is a view showing a modified example of the rivet according to the battery connection structure as one embodiment of the present invention, which is an enlarged view of the structure of the rivet having the flat head portion and the solid shaft portion. It is a typical side view.

4A and 4B are views showing a structure of a modified example of the head portion of the rivet according to the battery connection structure as the embodiment of the present invention, in which FIG. 4A is an enlarged schematic side view, and FIG. FIG. 3A is a sectional view taken along the line A2-A2 of FIG.

FIG. 5 is a schematic enlarged view showing the structure of a modified example of the head portion of the rivet according to the battery connection structure as one embodiment of the present invention, in which (A) and (B) are both shown in FIG. It is a figure corresponding to B).

FIG. 6 is a schematic view showing a structure of a battery (with a connector) as one embodiment of the present invention.

FIG. 7 is a schematic perspective view showing an overall configuration of a battery unit to which a battery connection structure according to an embodiment of the present invention is applied.

FIG. 8 is a schematic perspective view showing an overall configuration of a molding process example of an exterior material according to the battery connection structure according to the embodiment of the present invention.

FIG. 9 is a schematic cross-sectional view of essential parts showing an enlarged terminal binding structure of a single battery to which the battery connection structure according to the embodiment of the present invention is applied.

FIG. 10 is a schematic cross-sectional view showing an enlarged structure of an exterior member according to the battery connection structure according to the embodiment of the present invention.

FIG. 11 is a schematic cross-sectional view of an essential part showing an enlarged structure of a unit battery element according to a battery connection structure as one embodiment of the present invention.

FIG. 12 is a perspective view showing the structure of a battery as an embodiment of the present invention.

[Explanation of symbols]

1 Battery body 2 Flat lead 3 circuit board 4 rivets 4A, 4A 'head part 4B, 4B 'shaft 4C protrusion 4D groove 4E groove 5 battery elements 6 Exterior material (housing) 7 Sealing part of exterior material 6 8, 9 holes 10 connectors 11 Wiring for connectors with wiring 12 outer edge 13, 13A, 13B tabs 14 unit battery element 14A positive electrode 14B negative electrode 14C electrolyte layer 15A, 15B Current collector 16A positive electrode active material 16B Negative electrode active material 17 Housing 18 metal layers 19, 19A, 19B Synthetic resin layer 20 adhesive

Continued front page    F-term (reference) 5H022 AA09 CC02 CC10 EE01                 5H040 AA03 AA07 AS13 AT04 DD01                       DD10 JJ03

Claims (6)

[Claims] 1. A flat plate lead and a circuit board made of metal, which are electrically connected to the positive electrode and the negative electrode independently of each other, and the flat plate lead and the circuit board are connected by rivets. A battery to do. 2. A battery element is interposed between outer casings, and peripheral portions of the outer casings are sealed by heat fusion to seal the battery element. The positive electrode and the negative electrode are electrically isolated from each other. The metal plate-like lead connected to the external conductor penetrates the sealing part of the exterior material to the outside of the exterior material, and the circuit board is placed on the heat-sealing portion of the exterior material on the side where the flat lead penetrates. The battery according to claim 1, which is installed. 3. The battery according to claim 1, which has a connector with wiring, and the wiring of the connector with wiring is soldered on a circuit board. 4. The battery according to claim 1, wherein the connector is soldered on the circuit board. 5. An electric device equipped with the battery according to claim 1. 6. A mobile phone equipped with the battery according to claim 1.