JP2004171893A - Method for connecting battery and board, and battery unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce size and costs, and enhance connection reliability. <P>SOLUTION: A polymer battery 2 has a cell element 4 having a positive electrode terminal 12 and a negative electrode terminal 15, and an exterior package material 5 housing the cell element 4 so that the positive electrode terminal 12 and the negative electrode terminal 15 are led outside. The circuit board 3 has a connection land part 18 connected to each terminal 12 and 15. By directly connecting a portion leading out the terminals 12 and 15 to the connection land part 18, size is reduced since a distance between the polymer battery 2 and the circuit board 3 becomes short, costs are reduced since extra parts are not used due to direct connection, and connection reliability is enhanced since there are fewer connection portions. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for connecting a battery to a substrate, which suitably connects the battery to a circuit board, and a battery unit in which the battery is suitably connected to the circuit board.
[0002]
[Prior art]
In recent years, for example, a lithium ion is used as a positive electrode and a negative electrode as a power source of a portable electronic device such as a notebook computer, a personal digital assistant (PDA), a portable telephone, a camera-integrated VTR (Video Tape Recorder), and the like. A charge / discharge reaction is performed by moving the lithium ion secondary battery, and the development of a lightweight and high energy density lithium ion secondary battery is being promoted.
[0003]
The lithium ion secondary battery is required to be further reduced in size and weight because it is mounted on the portable electronic device described above. By using a solid electrolyte instead of the water electrolyte, further reduction in size and weight can be achieved.
[0004]
Specifically, in a lithium-ion secondary battery, for example, a laminate film in which a heat-fusible polymer film and a metal foil are laminated as a film-like exterior material is used, and a non-aqueous electrolyte is used as a solid electrolyte. A gel electrolyte or the like contained in a polymer matrix is used.
[0005]
A lithium ion secondary battery using such a laminate film and a gel electrolyte is generally called a polymer battery. And it is comprised in the battery unit 100 shown in FIG.
[0006]
A battery unit 100 mounted on an electronic device includes a polymer battery 101 serving as a power generation element, and a circuit board 102 to which the polymer battery 101 is connected.
In the polymer battery 101, a battery element 103 that is charged and discharged by a positive electrode and a negative electrode (not shown) is housed in an outer package 104, and a positive terminal 105 and a negative terminal 106 are respectively led out of the outer package 104 from the battery element 103. Configuration. In the polymer battery 101, a conductive metal made of aluminum or the like is used for the positive electrode terminal 105, and a conductive metal made of nickel or the like is used for the negative electrode terminal 106 so that trouble due to the battery potential does not occur. .
[0007]
The circuit board 102 includes an electronic circuit (not shown) for the purpose of, for example, overcharge protection or charge / discharge control, and a connection land 107 to which a terminal or the like for supplying electricity or the like to the electronic circuit or the like is connected. I have. In the circuit board 102, the positive terminal 105 and the negative terminal 106 are connected to the connection lands 107 via the relay tabs 108 made of a conductive metal such as nickel, and electricity is supplied from the polymer battery 101. become. In this circuit board 102, a conductive metal such as copper is used for the connection land 107 because of its excellent electrical conductivity and low cost.
[0008]
In the battery unit 100 having the above-described configuration, it is difficult to directly connect the positive terminal 105 made of aluminum or the like and the connection land 107 made of copper or the like by, for example, soldering or resistance welding. The positive terminal 105 and the connection land 107 are connected via a relay tab 108 made of. Specifically, after connecting the connection land 107 and the relay tab 108 by, for example, soldering by a reflow process, the positive terminal 105 is connected to the relay tab 108 connected to the connection land 107 by resistance welding or the like.
[0009]
On the other hand, the negative electrode terminal 106 made of nickel or the like can be directly connected to the connection land 107 by soldering or the like. However, if the reflow treatment is performed, the polymer battery 101 is deteriorated by heat. The connection tab 108 is connected by resistance welding or the like.
In this battery unit 100, since the connection between the polymer battery 101 and the circuit board 102 is connected via the relay tab 108, the distance between the polymer battery 101 and the circuit board 102 becomes longer by the length of the relay tab 108, so that the size of the battery unit 100 can be reduced. It becomes difficult to do. For this reason, the battery unit 100 requires a large space when housed in, for example, an electronic device, and the size of the mounted electronic device is increased.
[0010]
Further, in the battery unit 100, when the relay tab 108 is soldered to the connection land 107 of the circuit board 102 by reflow processing at a temperature of about 260 ° C. for 5 seconds or more, the circuit tab is heated by the heat during the reflow processing. The substrate 102 may be deteriorated.
[0011]
Furthermore, in the battery unit 100, the number of connection points for connecting the polymer battery 101 and the circuit board 102 is as large as four, and the number of steps related to connection such as reflow processing and welding processing is large. Will decrease. Furthermore, in this battery unit 100, since there are many connection points for connecting the polymer battery 101 and the circuit board 102, many inspection steps are required to maintain the connection reliability of all the connection points. And the production yield is further reduced.
[0012]
As a means for solving such a problem, the polymer battery and the circuit board are connected by caulking and fixing the positive terminal and the negative terminal with, for example, a crimp terminal or the like arranged on the connection land instead of the relay tab. Has been proposed. (For example, see Patent Document 1)
[Patent Document 1]
JP-A-2002-56834 (page 3-4, FIG. 19)
[0013]
[Problems to be solved by the invention]
However, in the connection method using the crimp terminal described above, although the distance between the polymer battery and the circuit board can be shortened, the crimp terminal crimping step and the like in addition to the welding step are increased, thereby improving the manufacturing yield. It is difficult to do.
[0014]
Also, in this connection method, the connection between the positive terminal and the negative terminal and the crimp terminal is performed by contact, and the connection reliability is lower than the connection by welding. The crimping of the crimp terminal may be loosened and the connection between the polymer battery and the circuit board may be interrupted.
[0015]
Therefore, the present invention has been proposed in view of such a conventional situation, and it is possible to improve the connection reliability between a battery and a circuit board and the production yield, and to reduce the size and cost. It is an object of the present invention to provide a connection method between a battery and a substrate, and a battery unit.
[0016]
[Means for Solving the Problems]
A method for connecting a battery and a substrate according to the present invention that achieves the above object is a method for connecting a battery to a circuit board to which the battery is connected, and includes a positive electrode having a positive terminal and a negative electrode having a negative terminal. A battery element laminated with a separator interposed therebetween is a portion that is led out of the positive electrode terminal and the negative electrode terminal of a battery manufactured by being housed in an exterior material such that the positive electrode terminal and the negative electrode terminal are led out. , Each of which is directly connected to a connection portion of a circuit board.
[0017]
In this connection method between the battery and the board, the distance between the battery and the circuit board can be shortened by directly connecting the portions led out of the positive electrode terminal and the negative electrode terminal of the battery to the connection portions of the circuit board, respectively. In addition, the number of welding points for connecting the battery and the circuit board is reduced to one at each of the positive terminal and the negative terminal, and the production yield can be improved.
[0018]
Further, the method of connecting the battery to the substrate is characterized in that the portions led out of the positive electrode terminal and the negative electrode terminal of the battery are directly connected to the connection portions of the circuit board by ultrasonic welding.
[0019]
As a result, in this method of connecting the battery to the board, it is possible to prevent the circuit board from deteriorating due to the heat generated by heating the circuit board in a conventional reflow process or the like, and to prevent the connection between the battery terminal and the connection portion of the circuit board. Connection with higher connection reliability can be performed as compared with the case where connection is performed with a crimp terminal or the like.
[0020]
A battery unit according to the present invention that achieves the above object has a battery element in which a positive electrode having a positive electrode terminal and a negative electrode having a negative electrode terminal are stacked with a separator interposed therebetween, and a positive electrode terminal and a negative electrode terminal are led out to the outside. A battery having an exterior material for accommodating the battery element, and a circuit board having a connection portion to which a positive electrode terminal and a negative electrode terminal are connected. Is directly connected to the connection part.
[0021]
In this battery unit, the portions leading out of the positive electrode terminal and the negative electrode terminal of the battery are directly connected to the connection portions of the circuit board, respectively, so that the distance between the battery and the circuit board can be shortened, and the size of the battery unit can be reduced. it can.
[0022]
Further, this battery unit is characterized in that the portions leading out of the positive electrode terminal and the negative electrode terminal of the battery are directly connected to the connection portions of the circuit board by ultrasonic welding, respectively.
[0023]
As a result, in this battery unit, it is possible to prevent the circuit board from being deteriorated due to the heat generated by heating the circuit board in a conventional reflow process or the like, and to compare the connection between the battery and the circuit board with crimp terminals. The connection reliability when the battery and the circuit board are connected can be improved.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a method for connecting a battery to a substrate and a battery unit to which the present invention is applied will be described with reference to a battery unit 1 shown in FIG.
[0025]
The battery unit 1 includes a polymer battery 2 serving as a power generation element and a circuit board 3 to which the polymer battery 2 is connected.
[0026]
In the battery unit 1, the polymer battery 2 is a non-aqueous electrolyte battery such as a lithium ion secondary battery, for example, and a battery element 4 in which a battery reaction such as charging and discharging is performed, and a film-like exterior material 5 enclosing the battery element 4. And
[0027]
As shown in FIG. 2, in the polymer battery 2, the battery element 4 has a band-shaped positive electrode 6 and a band-shaped negative electrode 7 with a solid electrolyte 8 containing an organic polymer or an electrolyte salt and a separator 9 interposed therebetween. In this state, the electrode functions as a power generating element by being wound in the longitudinal direction of the electrode.
[0028]
The positive electrode 6 is formed by applying a positive electrode mixture coating liquid containing a positive electrode active material and a binder on the positive electrode current collector 10, drying and applying pressure to form a positive electrode mixture layer 11 on the positive electrode current collector 10. It has a structure formed by compression. A positive electrode terminal 12 is connected to the positive electrode 6 at a predetermined position of the positive electrode current collector 10 so as to protrude in the width direction of the positive electrode current collector 10. For the positive electrode terminal 12, for example, a strip-shaped metal piece made of a conductive metal such as aluminum is used.
[0029]
For the positive electrode active material, for example, Li which can relatively increase the battery capacity is used. _x MO ₂ (Where M represents one or more transition metals such as Co, Ni, Mn, Fe, Al, V, and Ti, and x is in the range of 0.5 to 1.10). Use an oxide or the like. As the transition metal M constituting the lithium composite oxide, Co, Ni, Mn, or the like is preferable. As a specific example of such a lithium composite oxide, Li _x CoO ₂ , Li _x NiO ₂ , Li _x Ni _y Co _1-y O ₂ (Where 0 <y <1), LiMn ₂ O ₄ And the like. As the positive electrode active material, a material having a stable crystal structure at a low cost, for example, Li _x M _y PO ₄ (Where M is at least one of Fe, Mn, Cr, Co, Cu, Ni, V, Mo, Ti, Zn, Al, Ga, Mg, B, Nb, SnCa, and Sr; .Ltoreq.x.ltoreq.1.1 and 0.5.ltoreq.y.ltoreq.1). ₄ And so on. Further, as the positive electrode active material, for example, TiS ₂ , MoS ₂ , NbSe ₂ , V ₂ O ₅ And other metal sulfides or oxides.
[0030]
In the positive electrode 6, as a binder of the positive electrode mixture layer 11, for example, a binder such as polyvinylidene fluoride, polyvinylpyridine, polytetrafluoroethylene, or the like used in the positive electrode mixture of the nonaqueous electrolyte battery can be used. For example, a carbonaceous material or the like as a conductive material or a known additive or the like can be added to the positive electrode mixture layer 11. In the positive electrode 6, for the positive electrode current collector 10, for example, a foil-like metal or a net-like metal made of a conductive metal such as aluminum is used.
[0031]
The negative electrode 7 is formed by applying a negative electrode mixture coating liquid containing a negative electrode active material and a binder on the negative electrode current collector 13, drying, and pressurizing the negative electrode mixture layer 14 on the negative electrode current collector 13. It has a structure formed by compression. A negative electrode terminal 15 is connected to the negative electrode 7 at a predetermined position on the negative electrode current collector 13 so as to protrude in the width direction of the negative electrode current collector 13. For the negative electrode terminal 15, a strip-shaped metal piece made of a conductive metal such as nickel or copper is used.
[0032]
As the negative electrode active material, a material having a potential of 2 V or less with respect to lithium and doping / dedoping lithium is used. Specifically, for example, lithium, a lithium alloy, or a carbonaceous material capable of doping and undoping lithium ions is used. Examples of the carbonaceous material that can be doped / undoped with lithium ions include a low-crystalline carbon material obtained by firing at a relatively low temperature of 2000 ° C. or less, and artificial graphite obtained by firing a raw material that easily crystallizes at a high temperature of about 3000 ° C. It is possible to use a highly crystalline carbon material or the like. Specifically, carbonaceous materials such as pyrolytic carbons, cokes, graphites, glassy carbon fibers, organic polymer compound fired bodies, carbon fibers, and activated carbon can be used. Examples of cokes include pitch coke, needle coke, petroleum coke, and the like. The organic polymer compound fired body is obtained by firing a phenol resin, a furan resin, or the like at an appropriate temperature and carbonizing the same.
[0033]
In addition, as the negative electrode active material, for example, an element that can be combined with lithium, a compound of this element, or the like can be used in addition to the above-described carbonaceous material. Specifically, for example, the chemical formula D _s E _t Li _u (D is one or more of a metal element and / or a semiconductor element which can be combined with lithium, E is one or more of a metal element and / or a semiconductor element other than lithium and D, s is larger than 0, t and u Is 0 or more.) ₄ , SiB ₆ , Mg ₂ Si, Mg ₂ Sn, Ni ₂ Si, TiSi ₂ , MoSi ₂ , CoSi ₂ , NiSi ₂ , CaSi ₂ , CrSi ₂ , Cu ₅ Si, FeSi ₂ , MnSi ₂ , NbSi ₂ , TaSi ₂ , VSi ₂ , WSi ₂ , ZnSi ₂ And any one or more of these. These compounds can be used as a mixture of one or more of the above-described carbonaceous materials. In this case, the carbonaceous material functions as a conductive material.
[0034]
In addition to the above-mentioned carbonaceous materials and compounds, as the negative electrode active material, for example, a polymer such as polyacetylene or polypyrrole, or a relatively potential such as iron oxide, ruthenium oxide, molybdenum oxide, tungsten oxide, titanium oxide, tin oxide, or the like is used. It is also possible to use an oxide that is base and capable of doping and undoping lithium, a nitride obtained by replacing oxygen of these oxides with nitrogen, and the like.
[0035]
In the negative electrode 7, as the binder of the negative electrode mixture layer 11, for example, a binder such as polyvinylidene fluoride, polyvinylpyridine, polytetrafluoroethylene, or the like used in the negative electrode mixture of the nonaqueous electrolyte battery can be used. In the negative electrode 7, for the negative electrode current collector 13, for example, a foil-like metal or a net-like metal made of a conductive metal such as copper is used.
[0036]
The solid electrolyte 8 exchanges, for example, lithium ions between the positive electrode 6 and the negative electrode 7. Therefore, an organic solid electrolyte having lithium ion conductivity is used as the solid electrolyte 8. As the organic solid electrolyte, a polymer solid electrolyte composed of an electrolyte salt and an organic polymer containing the same, a gel electrolyte in which a non-aqueous electrolyte is contained in a polymer matrix, and the like can be used. The solid electrolyte 8 is formed as an electrolyte layer by applying and solidifying an electrolyte solution containing an organic solid electrolyte on the surfaces of the positive electrode 6 and the negative electrode 7.
[0037]
In the solid electrolyte 8, an electrolyte salt usually used for a non-aqueous electrolyte battery can be used. Specifically, LiPF ₆ , LiBF ₄ , LiAsF ₆ , LiClO ₄ , LiB (C ₆ H ₅ ) ₄ , CH ₃ SO ₃ Li, CF ₃ SO ₃ Li, LiC ₄ F ₉ SO ₃ , LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ C ₂ F ₅ ) ₂ , LiC (SO ₂ CF ₃ ) ₃ , LiAlCl ₄ , LiSiF ₆ , LiCl, LiBr and the like, and one or more of these are used as a mixture. In particular, as an electrolyte salt, LiPF which is excellent in oxidation stability is used. ₆ , LiBF ₄ Is used.
[0038]
In the solid electrolyte 8, as an organic polymer containing an electrolyte salt of the polymer solid electrolyte, for example, an ether polymer such as poly (ethylene oxide) or the same crosslinked product, a poly (methacrylate) ester polymer, and an acrylate polymer A polymer or the like can be used alone or copolymerized and mixed in the molecule.
[0039]
In the case of the gel electrolyte, in the solid electrolyte 8, a solvent having a relatively high dielectric constant is used as a non-aqueous solvent for dissolving the above-mentioned electrolyte salt to form a non-aqueous electrolyte. In this case, the non-aqueous electrolyte functions as a plasticizer. Specifically, as the non-aqueous solvent, for example, ethylene carbonate, propylene carbonate, γ-butyl lactone, diethyl carbonate, dimethyl carbonate, 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, diethyl ether, sulfolane, methylsulfolane, acetonitrile, propionitrile, acetate, butyrate, propionate, and the like. Mix and use a plurality of types.
[0040]
In the solid electrolyte 8, various polymers can be used as long as the polymer matrix containing the non-aqueous electrolyte of the gel electrolyte can absorb the non-aqueous electrolyte and gel. Specifically, for example, fluoropolymers such as poly (vinylidenefluoride) and poly (vinylidenefluoride-co-hexafluoropropylene), and ether polymers such as poly (ethylene oxide) and cross-linked products thereof , Poly (acrylonitrile) and the like, and any one or a mixture of these may be used.
[0041]
The separator 9 separates the positive electrode 6 and the negative electrode 7 from each other, and a known material that is generally used as an insulating porous film of this type of nonaqueous electrolyte battery can be used. Specifically, for example, a polymer film such as polypropylene or polyethylene is used. Further, from the relationship between the lithium ion conductivity and the energy density, the thickness of the separator 9 is preferably as thin as possible, and the separator 9 is used with a thickness of 30 μm or less. Thereby, in the polymer battery 2, the lithium ion conductivity between the positive electrode 6 and the negative electrode 7 can be improved, and a high energy density can be obtained.
[0042]
The packaging material 5 for enclosing the battery element 4 having the above-described configuration is a laminated film in which a resin layer and a metal layer are bonded to each other by lamination or the like to form a composite of two or more layers. The surface to be formed is a resin layer. The material of the resin layer is not particularly limited as long as it has an adhesive property to the positive electrode terminal 12 and the negative electrode terminal 15, for example, polyethylene, polypropylene, modified polyethylene, modified polypropylene and a copolymer thereof, a polyolefin resin and the like. Such an organic resin material is used because it can lower the permeability of atmospheric moisture and is excellent in airtightness. As the metal layer, for example, aluminum, stainless steel, nickel, iron, or the like formed into a foil shape, a plate shape, or the like is used. In addition, in the exterior material 5, by providing a resin layer made of, for example, nylon or the like on the layer serving as the outer peripheral layer of the polymer battery 2, the strength against breakage or piercing can be improved.
[0043]
The polymer battery 2 having such a configuration is manufactured as follows. First, the positive electrode 6 is manufactured. When producing the positive electrode 6, a positive electrode mixture coating solution containing the above-described positive electrode active material, conductive material, and binder is prepared, and the positive electrode mixture coating solution is made of, for example, a positive electrode current collector made of aluminum foil or the like. The positive electrode mixture layer 11 is compression-formed by uniformly applying, drying, and applying pressure so as to provide an uncoated portion on 10 and cut into a predetermined size. Next, the positive electrode terminal 12 is connected to the uncoated portion where the positive electrode current collector 10 is exposed, for example, by ultrasonic welding or spot welding. Thus, the belt-shaped positive electrode 6 is manufactured.
[0044]
Next, the negative electrode 7 is manufactured. When producing the negative electrode 7, a negative electrode mixture coating liquid containing the above-described negative electrode active material and a binder is prepared, and the negative electrode mixture coating liquid is placed on a negative electrode current collector 13 made of, for example, copper foil or the like. The negative electrode mixture layer 14 is compression-formed by uniformly applying, drying, and pressing so as to provide an uncoated portion, and cut into a predetermined size. Next, the negative electrode terminal 15 is connected to the uncoated portion where the negative electrode current collector 13 is exposed, for example, by ultrasonic welding or spot welding. Thus, the strip-shaped negative electrode 7 is manufactured.
[0045]
Next, the solid electrolytes 8 are formed in layers on the main surface of the positive electrode mixture layer 11 of the positive electrode 6 and the main surface of the negative electrode mixture layer 14 of the negative electrode 7, respectively. When forming the solid electrolyte 8, the electrolyte salt is dissolved in a non-aqueous solvent to prepare a non-aqueous electrolyte. Next, this non-aqueous electrolyte, an organic polymer or a matrix polymer, and a non-aqueous solvent as a diluting solvent are mixed and stirred as necessary to prepare an electrolyte solution in a sol state. The polymer solid electrolyte layer is formed by coating the main surface of the positive electrode mixture layer 11 of No. 6 and the main surface of the negative electrode mixture layer 14 of the negative electrode 7. When a diluting solvent is used, the non-aqueous solvent is volatilized to form a gel electrolyte layer. Thus, the solid electrolyte 8 is formed as an electrolyte layer on the positive electrode 6 and the negative electrode 7, respectively.
[0046]
Next, the positive electrode 6 and the negative electrode 7 each having the solid electrolyte 8 formed on the main surface as described above are wound many times in the longitudinal direction via the separator 9 so as to face the electrolyte layers, and are flatly wound. The battery element 4 is manufactured. In the battery element 4, the positive electrode terminal 12 and the negative electrode terminal 15 are projected from one end surface in the winding axis direction.
[0047]
Next, the battery element 4 is housed inside the exterior material 5 while the positive electrode terminal 12 and the negative electrode terminal 15 provided on the battery element 4 are led out. At this time, the battery element 4 is housed in the exterior material 5 such that a resin piece 16 made of propylene or the like having adhesiveness is applied between the positive electrode terminal 12 and the negative electrode terminal 15 and the exterior material 5. As a result, in the polymer battery 2, a short circuit between the positive electrode terminal 12 and the negative electrode terminal 15 and the metal layer of the exterior material 5, a reduction in airtightness, and the like are prevented.
[0048]
Next, the battery element 4 is encapsulated in the exterior material 5 by attaching the peripheral edge of the exterior material 5 in which the battery element 4 is housed by, for example, heat sealing or the like. Thus, the polymer battery 2 is manufactured.
[0049]
In the battery unit 1, the circuit board 3 includes a base substrate 17 made of an insulating material, a connection land portion 18 formed on a main surface of the base substrate 17, and an electronic device arranged on the base substrate together with the connection land portion 18. And a circuit unit 19.
[0050]
The base substrate 17 is formed of an organic material such as a phenol resin or a polyolefin resin, an inorganic material such as a ceramic, or an insulating material such as a mixture of an organic material and an inorganic material such as a glass epoxy.
[0051]
The connection land 18 is formed of a conductive metal such as copper or gold, for example, because the positive terminal 12 and the negative terminal 15 of the polymer battery 2 are connected to each other. The connection land 18 is formed by forming a conductive metal into a predetermined shape on the main surface 3a of the circuit board 3 by a film forming technique such as plating or vapor deposition. The connection lands 18 are made of an inexpensive material such as copper, so that the cost can be reduced and excellent electrical conductivity can be obtained.
[0052]
The electronic circuit unit 19 is an electronic circuit that performs at least overcharge protection and charge / discharge control on, for example, the polymer battery 2. Specifically, the electronic circuit is, for example, an electronic circuit such as a semiconductor chip or an LSI (Large-scale Integrated Circuit) chip. The electronic circuit section 19 is electrically connected to the connection land section 18 by a not-shown pattern wiring or the like formed on an inner layer of the base substrate 17. The electronic circuit section 19 functions by being supplied with electricity from the polymer battery 2 via the positive terminal 12 and the negative terminal 15 connected to the connection land 18.
[0053]
The battery unit 1 has a configuration in which the polymer battery 2 is directly connected to the circuit board 3. Specifically, in the battery unit 1, the portions of the polymer battery 2 that are led out of the outer package 5 of the positive electrode terminal 12 and the negative electrode terminal 15 are directly connected to the connection lands 18 of the circuit board 3 by ultrasonic welding, respectively. ing.
[0054]
As a result, in the battery unit 1, the distance between the polymer battery 2 and the circuit board 3 is shorter than that in the case where the relay tab is used to connect the polymer battery and the circuit board as in the related art, and the size is reduced. I can plan.
[0055]
Also, in this battery unit 1, the number of welding locations at the positive electrode terminal 12 and the negative electrode terminal 15 is smaller than that in the case where a conventional welding tab is used, so that the connection reliability between the polymer battery 2 and the circuit board 3 is reduced. Performance can be improved.
[0056]
Further, in the battery unit 1, the connection reliability between the polymer battery 2 and the circuit board 3 can be improved as compared with the conventional case where a crimp terminal is used to connect the polymer battery to the circuit board.
[0057]
Furthermore, in the battery unit 1, the connection between the polymer battery 2 and the circuit board 3 is performed by ultrasonic welding, so that the circuit board is heated by the conventional heating of the circuit board by reflow processing or the like. Degradation can be prevented.
[0058]
In the battery unit 1 described above, the polymer battery 2 and the circuit board 3 are directly connected by ultrasonic welding by the ultrasonic welding machine 30 (manufactured by Altex Corporation: Model 40MP) shown in FIGS. It is produced by
[0059]
The ultrasonic welding machine 30 used to manufacture the battery unit 1 will be described. The ultrasonic welding machine 30 includes a vibration unit 31 for oscillating ultrasonic waves, a horn 32 connected to the vibration unit 31, an anvil 33 for mounting the circuit board 3, and a polymer battery 2. It has a receiving table 34 to be placed, a driving section 35 for driving the horn section 32 so as to press it against the welding point, and a control computer 36 for controlling the entire apparatus.
[0060]
The vibration unit 31 includes, for example, an oscillator that oscillates an ultrasonic wave having a predetermined amplitude when supplied with electricity.
[0061]
The horn portion 32 is provided with a welding tip 37 for transmitting ultrasonic waves oscillated by the vibration unit 31 to a workpiece to be welded and detachable. Thereby, various kinds of welding tips 37 can be replaced and used. Further, the welding tip 37 may not be detachable, and the horn portion 32 and the welding tip 37 may be integrally formed.
[0062]
The welding tip 37 is provided with an uneven pattern of a predetermined shape on the main surface 37a facing the work to be welded so that when the main surface 37a contacts the work, the uneven pattern cuts into the work to be welded. Have been. In the case of the present embodiment, the welding tip 37 is pressed against one main surface 12a of the positive electrode terminal 12 and one main surface 15a of the negative electrode terminal 15, and the concave and convex pattern of the main surface 37a is changed to the positive electrode terminal 12 and the negative electrode terminal 15. Of one of the main surfaces 12a and 15a. In the welding tip 37, the area of the main surface 37a is about 2 mm × 4 mm.
[0063]
The anvil portion 33 is provided with a concavo-convex pattern of a predetermined shape on a main surface 33a facing the circuit board 3 in order to appropriately fix the mounted circuit board 3.
[0064]
The pedestal 34 has a main surface 3 a of the circuit board 3 placed on the anvil portion 33 on which the welding lands 18 are formed, and another main surface opposite to the main surface 12 a of the positive electrode terminal 12 of the polymer battery 2. The polymer battery 2 is mounted such that the other main surface 15b opposite to the main surface 12b and the one main surface 15a of the negative electrode terminal 15 have the same height.
[0065]
The drive unit 35 is a unit that drives the main surface 33 a of the anvil unit 33 in a substantially vertical direction indicated by an arrow A in FIGS. 3 and 4.
[0066]
The driving unit 35 drives the horn 32 in a direction substantially perpendicular to the main surface 33 a of the anvil 33 so that the main surface 37 a of the welding tip 37 provided on the horn 32 is A predetermined pressure is applied to one main surface 12a of the positive terminal 12 or one main surface 15a of the negative terminal 15 placed on the main surface 33a via the circuit board 3. In the ultrasonic welding machine 30, the pressure at which the main surface 37a of the welding tip 37 is pressed against the welding location when the driving unit 35 is driven can be changed in two stages.
[0067]
The control computer 36 controls the entire apparatus with electric power supplied from the outside, and includes an input unit 38 for inputting various welding conditions, a control unit (not shown) for controlling the vibration unit 31 and the drive unit 35, and the like.
[0068]
The input unit 38 includes a switch for a user to input various welding conditions in the ultrasonic welding machine 30, a welding start switch, and the like. The input unit 38 outputs the welding condition input by the user as an operation signal to, for example, a control unit or the like via an interface or the like.
[0069]
The control unit includes, for example, a central processing unit (hereinafter, referred to as a CPU) and the like, and controls the entire ultrasonic welding machine 30 in accordance with an operation signal transmitted from the input unit 38. The control unit outputs an operation signal based on the welding conditions input by the input unit 38 to, for example, the vibration unit 31 or the driving unit 35 via an interface or the like. Specifically, the control section outputs conditions such as the amplitude and the oscillation time of the ultrasonic wave to the vibration generating unit 31 as operation signals, and the pressure at which the welding tip 37 of the horn section 32 is pressed against the welding location or the pressure is pressed. The conditions such as time are output as an operation signal to the drive unit 35.
[0070]
When connecting the polymer battery 2 and the circuit board 3 by using the ultrasonic welding machine 30 having the above configuration, first, the circuit board 3 is placed on the main surface 33a of the anvil portion 33, The polymer battery 2 is placed thereon. At this time, the polymer battery 2 is mounted on the receiving stand 34 such that the positive terminal 12 and the negative terminal 15 face the connection lands 18 formed on the main surface 3a of the circuit board 3 respectively.
[0071]
Next, in the ultrasonic welding machine 30, a user inputs welding conditions such as, for example, the amplitude of the ultrasonic wave, the pressure for pressurizing the welding point, and the pressurizing time to the input unit 38 of the control computer 36. Specifically, in this embodiment, the amplitude of the ultrasonic wave is 5 μm, the pressure for applying pressure to the first-stage welding portion is 20 N, the first-stage pressurizing time is 0.05 seconds, and the pressure for applying pressure to the second-stage welding portion. Welding conditions such as 30 N and a first stage pressurization time of 0.1 second were input.
[0072]
Next, in the ultrasonic welding machine 30, the user turns on the input start switch of the input unit 38. Here, the ultrasonic connection between the positive electrode terminal 12 and the connection land 18 will be described.
[0073]
Along with this, in the ultrasonic welding machine 30, the driving part 35 is driven to press the main surface 37 a of the welding tip 37 of the horn part 31 against the one main surface 12 a of the positive electrode terminal 12 at the first stage pressure and The ultrasonic wave having an amplitude of 5 μm oscillated by the vibration unit 31 is transmitted to the positive electrode terminal 12 via the horn 31 and the welding tip 37 only during the first-stage pressurization time.
[0074]
At this time, ultrasonic waves rub against each other at both interfaces where the positive electrode terminal 12 and the connection land portion 18 are in contact with each other to cause friction, thereby removing dirt and oxide films on the surface.
[0075]
Then, in the ultrasonic welding machine 30, the main surface 37a of the welding tip 37 is pressed against the one main surface 12a of the positive electrode terminal 12 by the second-stage pressure following the end of the first-stage welding time, Ultrasonic waves having an amplitude of 5 μm are transmitted to the positive electrode terminal 12 only during the second-stage pressurization time.
[0076]
At this time, at both interfaces where the positive electrode terminal 12 from which the oxide film or the like has been removed and the connection land portion 18 are in contact with each other, the friction is increased by being pressed with a pressure larger than the first stage, so that plastic deformation occurs and the new metal surfaces Adhesion is performed. More specifically, diffusion and recrystallization of metal atoms are promoted by a local temperature rise due to frictional heat, and the positive electrode terminal 12 and the connection land 18 are firmly connected directly. The direct connection between the negative electrode terminal 15 and the connection land 18 by ultrasonic welding is performed in the same manner. As described above, the battery unit 1 is manufactured by connecting the polymer battery 2 and the circuit board 3.
[0077]
In the method of connecting the polymer battery 2 and the circuit board 3 described above, it has conventionally been difficult to directly connect the positive terminal made of aluminum or the like to the connection land made of copper or the like. By using the welding machine 30, the positive electrode terminal 12 and the negative electrode terminal 15 can be easily directly connected to the connection land portion 18.
[0078]
As a result, in this connection method, the distance between the polymer battery 2 and the circuit board 3 is shortened, and the battery unit 1 that is reduced in size can be manufactured.
[0079]
Further, in this connection method, the number of welding points for connecting the polymer battery 2 and the circuit board 3 can be significantly reduced as compared with the case where a conventional relay tab is used, so that the welding process is reduced and the battery is reduced. The yield in manufacturing the unit 1 can be improved.
[0080]
Furthermore, according to this welding method, since an extra component such as a relay tab is not required for connecting the polymer battery 2 and the circuit board 3, the battery unit 1 can be manufactured at low cost.
[0081]
Furthermore, in this connection method, since the polymer battery 2 and the circuit board 3 can be directly connected by ultrasonic welding without heating, deterioration of the circuit board caused by heating in the conventional reflow process can be prevented. Furthermore, in this connection method, the battery unit 1 has improved connection reliability of the connection between the polymer battery 2 and the circuit board 3 as compared with the conventional connection between the polymer battery and the circuit board using crimp terminals or the like. Can be produced.
[0082]
In the connection method between the polymer battery 2 and the circuit board 3 described above, the ultrasonic waves generated in the vibration unit 31 and transmitted to the positive electrode terminal 12 via the horn portion 32 and the welding tip 37 are indicated by arrows in FIGS. This is ultrasonic vibration of vibration in a direction substantially parallel to the main surface 12a of the positive electrode terminal 12 indicated by B, so-called transverse vibration. Here, the connection between the positive electrode terminal 12 and the connection land 18 will be described.
[0083]
In the case where the ultrasonic waves transmitted to the positive electrode terminal 12 are vibrations in a direction substantially perpendicular to the main surface 12 a of the positive electrode terminal 12, that is, so-called longitudinal vibrations, the ultrasonic waves are applied to both interfaces where the positive electrode terminal 12 and the connection land portion 18 are in contact. It becomes difficult to generate friction due to sound waves, and the connection strength between the positive electrode terminal 12 and the connection land 18 may be reduced. In this case, the ultrasonic wave of the longitudinal vibration is excessively transmitted to the circuit board 3 below the positive electrode terminal 12, and the circuit board 3 may be deteriorated.
[0084]
Therefore, in the method of connecting the polymer battery 2 and the circuit board 3, the ultrasonic wave transmitted to the positive electrode terminal 12 is made into a lateral vibration, so that the positive electrode terminal 12 and the connection land portion 18 can be connected without deterioration of the circuit board 3. Direct connection with appropriate welding strength.
[0085]
More specifically, the tensile strength when pulled substantially perpendicularly to the positive terminal 12 and the connection land 18, that is, the strength that pulls the positive terminal 12 and separates from the welding land 18, depends on the connection tab being connected to the connection land by the reflow process. It is 3N or more, which is equivalent to that when solder welding is performed on the part.
[0086]
The same operation and effect can be obtained even when the ultrasonic wave transmitted to the negative electrode terminal 15 is set to the transverse vibration, and the negative electrode terminal 15 and the connection land 18 can be directly connected with an appropriate welding strength. Also in this case, the tensile strength when the negative electrode terminal 15 welded to the welding land portion 18 is pulled is 3 N or more.
[0087]
【The invention's effect】
As is apparent from the above description, according to the present invention, by directly connecting the battery and the circuit board by ultrasonic welding, the size and cost can be reduced, and the connection reliability between the battery and the circuit board can be improved. , And a battery unit with an increased yield can be manufactured with high yield.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a part of a battery unit to which the present invention is applied.
FIG. 2 is a longitudinal sectional view showing an internal structure of a polymer battery in the battery unit.
FIG. 3 is a perspective view showing an ultrasonic welding machine used for connecting a polymer battery and a circuit board in the battery unit, and showing a state where the polymer battery and the circuit board are placed.
FIG. 4 is a side view showing a part of the ultrasonic welding machine, schematically showing a state where a polymer battery and a circuit board are mounted.
FIG. 5 is a perspective view showing a part of a conventional battery unit in a see-through manner.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 battery unit, 2 polymer battery, 3 circuit board, 4 battery element, 5 exterior material, 6 positive electrode, 7 negative electrode, 8 solid electrolyte, 9 separator, 10 positive electrode current collector, 11 positive electrode mixture layer, 12 positive electrode terminal, 13 Negative electrode current collector, 14 Negative electrode mixture layer, 15 Negative electrode terminal, 16 Resin piece, 17 Base substrate, 18 Connection land, 19 Electronic circuit, 30 Ultrasonic welding machine, 31 Vibration unit, 32 Horn, 33 Anvil Unit, 34 cradle, 35 drive unit, 36 control computer, 37 welding tip, 38 input unit

Claims (9)

In a method for connecting a battery to a circuit board, wherein the battery is connected to a circuit board,
A battery element in which a positive electrode having a positive electrode terminal and a negative electrode having a negative electrode terminal are stacked with a separator interposed therebetween is manufactured by being housed in an exterior material such that the positive electrode terminal and the negative electrode terminal are led out. A method for connecting a battery and a substrate, wherein portions of the battery that are led out of the positive electrode terminal and the negative electrode terminal are directly connected to connection portions of the circuit board, respectively. 2. The method for connecting a battery to a substrate according to claim 1, wherein portions of the battery that are led out of the positive electrode terminal and the negative electrode terminal are directly connected to connection portions of the circuit board by ultrasonic welding. . The portions of the battery extending to the outside of the positive electrode terminal and the negative electrode terminal are each connected to the circuit board by ultrasonic welding using ultrasonic waves vibrating in a direction substantially parallel to the main surfaces of the positive electrode terminal and the negative electrode terminal. 3. The method for connecting a battery and a substrate according to claim 2, wherein the connection is directly made to the connection part. The connection between a battery and a substrate according to claim 1, wherein the positive electrode terminal contains aluminum, the negative electrode terminal contains nickel, and the connection portion of the circuit board contains copper. Method. A battery having a battery element in which a positive electrode having a positive electrode terminal and a negative electrode having a negative electrode terminal are stacked with a separator interposed therebetween, and an exterior material for housing the battery element so that the positive electrode terminal and the negative electrode terminal are led out to the outside When,
A circuit board having a connection portion to which the positive terminal and the negative terminal are connected,
A battery unit, wherein portions of the battery leading out of the positive electrode terminal and the negative electrode terminal are directly connected to connection portions of the circuit board, respectively. 6. The battery unit according to claim 5, wherein portions of the battery extending to the outside of the positive electrode terminal and the outside of the negative electrode terminal are each directly connected to a connection portion of the circuit board by ultrasonic welding. The battery unit according to claim 5, wherein the positive electrode terminal contains aluminum, the negative electrode terminal contains nickel, and the connection portion of the circuit board contains copper. The battery unit according to claim 5, wherein the exterior material is made of a laminated film. The battery unit according to claim 5, wherein the battery is a polymer battery in which the battery element includes a solid electrolyte containing an electrolyte salt.

Images