JP2005174661A - Power supply device, and connecting method of battery and substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply device in which connection to a battery and a control substrate is simplified and downsizing and improvement of battery characteristics are realized, and provide a connecting method of the battery and the substrate. <P>SOLUTION: This device is provided with a battery 2 which has a battery element 21 laminated between a positive electrode 23 and a negative electrode 24 via a separator 26, and in which reed terminals 27, 28 are drawn out from respective positive electrode 23 and negative electrode 24, the substrate 31, and the control substrate 3 which has a control element 32 that is surface mounted on the substrate 31 by at least one, and which controls an electric current against the battery 2. At least one of the reed terminals 27, 28 which are drawn out from the positive electrode 23 and the negative electrode 24 is directly connected to one control element 32. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a power supply device that is downsized and a method for connecting a battery and a substrate.

  In recent years, many portable electronic devices such as a camera-integrated video tape recorder, a mobile phone, and a portable computer have appeared, and their size and weight have been reduced. As electronic devices become smaller and lighter, power supply devices used as portable power sources are also required to have high energy and be reduced in size and weight. As a power supply device, for example, a high-capacity lithium ion secondary battery is provided with a control board (see, for example, Patent Document 1).

  The power supply device includes a control element, a control circuit, and the like that control the current flowing in the lithium ion secondary battery when the lithium ion secondary battery is overheated or overheated or overdischarged. Is provided. Thereby, the power supply device maintains safety and reliability. In the power supply device, for example, a PTC element (Positive Temperature Coefficient) for controlling a current flowing in a lithium ion secondary battery is provided as a control element between the lithium ion secondary battery and the circuit board. When the temperature rises due to the charge / discharge current of the lithium ion secondary battery or the heat from the lithium ion secondary battery, the PTC element has an increased impedance and reduces the current flowing through the lithium ion secondary battery. As described above, the PTC element has a role of preventing the lithium ion secondary battery from being overcharged, overcurrent, or overdischarged, and prevents the lithium ion secondary battery from being excessively heated.

  In the power supply device, when the PTC element is provided between the lithium ion secondary battery and the control board, between the PTC element and the lead terminal derived from the positive electrode or the negative electrode of the lithium ion secondary battery, and between the PTC element and the circuit board, Are connected with tabs. That is, in the power supply device, the PTC element is provided between the battery and the circuit board via the tab, and the PTC element is electrically connected to the lithium ion secondary battery and the circuit board. In such a power supply device, for example, when a pack is formed by being housed in an outer case or the like, a space for housing a tab connecting the PTC element, the lithium ion secondary battery, and the circuit board is required in the outer case. This will increase the size of the pack. Also, in the power supply device, in the manufacturing process, each tab is connected to each tab, such as spot welding the PTC element and the lead terminal of the lithium ion secondary battery, or soldering the tab and the control board. Therefore, there is a risk that the connection process increases and the connection between the lithium ion secondary battery and the control board becomes complicated. Further, in the power supply device, the connection with the tab increases the number of connection points between the lithium ion secondary battery and the circuit board, and the electrical connection between the lithium ion secondary battery and the circuit board becomes unstable. Furthermore, in the power supply device, since the connection between the lithium ion secondary battery and the circuit board becomes indirect by using a tab, the electrical resistance between the lithium ion secondary battery and the circuit board increases, and the battery characteristics Will fall. Therefore, in such a power supply device, it is necessary to reduce the electrical resistance between the lithium ion secondary battery and the circuit board.

JP 2002-8608 A

  The present invention has been proposed in view of such a conventional situation, and it is possible to simplify the connection between the battery and the control board, reduce the size, and improve the battery characteristics. An object is to provide a connection method.

  A power supply device according to the present invention that achieves the above-described object has a battery element having a battery element laminated via a separator between a positive electrode and a negative electrode, and a substrate in which a lead terminal is derived from each of the positive electrode and the negative electrode, and a substrate And at least one of the lead terminals led out from the positive electrode and the negative electrode, respectively, and a control board for controlling current with respect to the battery. It is directly connected to one control element.

  In the power supply device having the above-described configuration, the connection between the battery and the control board is simplified by directly connecting the battery lead terminal to the control element mounted on the surface of the board. Miniaturization is achieved without the need for members. Also, in the power supply device, by directly connecting the battery lead terminal to the control element, the number of connection points between the battery and the control board is reduced, so that the electrical connection between the control board and the battery is improved and the electric resistance is reduced. Since it becomes small, the fall of a battery characteristic can be suppressed.

  In addition, the battery and substrate connection method according to the present invention that achieves the above-described object includes a battery element in which a battery is stacked via a separator between a positive electrode and a negative electrode, and lead terminals from each of the positive electrode and the negative electrode. And at least one of the lead terminals led out from each of the positive electrode and the negative electrode is directly connected to at least one control element surface-mounted on the substrate.

  In the connection method between the battery and the substrate having the above-described configuration, the connection points between the battery and the substrate can be reduced by directly connecting the battery lead terminals to the control element mounted on the surface of the substrate. The electrical connection between the substrate and the battery can be improved, and the deterioration of the battery characteristics can be suppressed.

  In the present invention, the connection between the battery and the control board is simplified by directly connecting the lead terminals of the battery to the control element surface-mounted on the board, so that the size is reduced. Further, in the present invention, by directly connecting the lead terminal to the control element, the electrical connection between the control board and the battery is improved, and the yield of the power supply device is improved.

  Hereinafter, in an embodiment of the present invention, a battery pack 1 in which a power supply device to which the present invention is applied is formed in a pack shape will be described in detail with reference to the drawings. As shown in FIGS. 1 and 2, the battery pack 1 includes a lithium ion secondary battery 2 as a battery for supplying power to an electronic device and the like, and a control board 3 electrically connected to the lithium ion secondary battery 2. And a battery case 4 for housing the lithium ion secondary battery 2 and the control board 3.

  Since the lithium ion secondary battery 2 has a high capacity and is lightweight, it is used as a portable power source. As shown in FIGS. 3 to 5, the lithium ion secondary battery 2 includes a battery element 21 and an exterior material 22 that houses the battery element 21.

  The battery element 21 includes a positive electrode 23, a negative electrode 24, a gel electrolyte 25 formed on both surfaces of the positive electrode 23 and both surfaces of the negative electrode 24, a positive electrode 23 on which the gel electrolyte 25 is formed, and a negative electrode 24 on which the gel electrolyte 25 is formed. And a separator 26 interposed therebetween. The battery element 21 is wound with a separator 26 interposed between the gel electrolyte 25 of the positive electrode 23 and the gel electrolyte 25 of the negative electrode 24, a positive electrode lead 27 is connected to the positive electrode 23, and a negative electrode is connected to the negative electrode 5. A lead 28 is connected, and the positive electrode lead 27 and the negative electrode lead 28 protrude from one end surface. Thereby, the lithium ion secondary battery 2 has the battery element 21 in a state where the positive electrode lead 27 and the negative electrode lead 28 protruding from one end surface of the battery element 21 are sandwiched between the bonding surfaces 22a of the exterior material 22. Is enclosed in the exterior material 22.

  The positive electrode 23 is formed by forming a positive electrode active material layer 23b capable of doping and dedoping lithium ions on both main surfaces of the positive electrode current collector 23a.

  The material of the positive electrode current collector 23a is not limited, but for example, a net-like or foil-like conductive metal or the like is used. Specifically, for example, aluminum or the like is used as the conductive metal that becomes the positive electrode current collector 23a. A positive electrode lead 27 is welded to one end of the positive electrode current collector 23a by a welding method such as ultrasonic welding.

  The positive electrode active material layer 23b is formed by applying a positive electrode mixture on both main surfaces of the positive electrode current collector 23a by mixing a positive electrode active material and, if necessary, a positive electrode active material with a binder or a conductive agent. , Formed by drying.

As the positive electrode active material, the battery capacity can be made relatively large. For example, Li _x MO ₂ (wherein M is any one of Co, Ni, Mn, Fe, Al, V, Ti, etc.). A lithium composite oxide or the like mainly composed of the above transition metals (0.5 ≦ x ≦ 1.10) can be used. Further, as the transition metal M constituting the lithium composite oxide, it is preferable to use Co, Ni, Mn or the like. Specific examples of such lithium composite oxide include Li _x CoO ₂ and Li _x NiO _2. , Li _x Ni _y Co _1-y O ₂ (where 0 <y <1), LiMn ₂ O _{4 and the} like. Further, as the positive electrode active material, it is inexpensive and has a stable crystal structure, for example, Li _x M _y PO ₄ (wherein, M is Fe, Mn, Cr, Co, Cu, Ni, V, Mo, Ti, 1 or more of Zn, Al, Ga, Mg, B, Nb, SnCa and Sr, 0.5 ≦ x ≦ 1.1 and 0.5 ≦ y ≦ 1). A compound or the like can be used, and specific examples thereof include LiFePO _{4 and the} like. Further, as the cathode active material can also be used, for example _{TiS 2, MoS 2, NbSe 2} , V 2 O metal sulfides such as _5.

As the positive electrode active material, a material obtained by adding a compound having an olivine structure to the above-described lithium composite oxide or the like may be used. Examples of the compound having an olivine structure, for example, the general formula _{Li X Fe 1-y M y} PO 4 ( provided that, M is Mn, Cr, Co, Cu, Ni, V, Mo, Ti, Zn, Al, Ga, Mg , B, or Nb, 0.05 ≦ x ≦ 1.2, and 0 ≦ y ≦ 0.8.) Lithium iron phosphorous oxide can be used. Specific examples of such lithium iron phosphorous oxide include LiFePO ₄ , LiFe _0.2 Mn _0.8 PO ₄ , LiFe _0.2 Cr _0.8 PO ₄ , LiFe _0.2 Co _0.8 PO ₄ , LiFe _0.2 Cu _0.8 PO ₄ , LiFe _0.2 Ni _0.8 PO ₄ , LiFe _0.25 V _0.75 PO ₄ , LiFe _0.25 Mo _0.75 PO ₄ , LiFe _0.25 Ti _{0 .75} PO ₄ , LiFe _0.3 Zn _0.7 PO ₄ , LiFe _0.3 Al _0.7 PO ₄ , LiFe _0.3 Ga _0.7 PO ₄ , LiFe _0.25 Mg _0.75 PO ₄ , LiFe _{0. 25} B _0.75 PO ₄ , LiFe _0.25 Nb _0.75 PO _{4 and the} like. As the compound having an olivine structure, in addition to the lithium iron phosphate oxide described above _may be used LiCoPO _4, LiMnPO _4, LiCuPO ₄ like.

  Since these compounds having an olivine structure have high thermal stability, the overcharge safety and the overdischarge durability of the lithium ion secondary battery 2 can be improved by adding them to the lithium composite oxide. The ratio of the compound having an olivine structure added to the lithium composite oxide or the like is about 10% with respect to the whole positive electrode active material forming the positive electrode active material layer 23b.

  The binder is, for example, polyvinylidene fluoride, polyvinyl pyridine, polytetrafluoroethylene, or the like used for a positive electrode mixture used in a general non-aqueous electrolyte battery. Further, for example, a carbonaceous material or the like may be added to the positive electrode mixture as a conductive material, or other known additives may be added.

  The positive electrode 23 is electrically connected to a positive electrode lead 27 formed of, for example, aluminum or the like in a strip shape. The positive electrode lead 27 has a positive electrode active material layer 23 b in accordance with the exposed portion of the positive electrode current collector 23 a provided at one end in the longitudinal direction of the positive electrode 23 (for example, the end on the inner peripheral side), that is, the width of the positive electrode lead 27. The positive electrode current collector 23a is exposed without being formed, and is joined by resistance welding, ultrasonic welding, or the like. The positive electrode lead 27 is provided with one end extending from the width direction of the positive electrode 23.

  The negative electrode 24 is formed by forming a negative electrode active material layer 24b capable of doping and dedoping lithium ions on both main surfaces of the negative electrode current collector 24a.

  The material of the negative electrode current collector 24a is not limited, but for example, a net-like or foil-like conductive metal is used. Specifically, for example, nickel or copper is used as the conductive metal to be the negative electrode current collector 24a. A negative electrode lead 28 is welded to one end of the negative electrode current collector 24a by a welding method such as ultrasonic welding.

  The negative electrode active material layer is formed by mixing a negative electrode active material and, if necessary, a negative electrode active material with a binder or a conductive agent.

  The negative electrode active material is not particularly limited as long as it is a material that can be doped / undoped with an alkali metal such as lithium in accordance with a charge / discharge reaction. Specific examples of the negative electrode active material include conductive polymers such as polyacetylene and polypyrrole, pyrolytic carbons, cokes, carbon black, glassy carbon, organic polymer material fired bodies, and carbon fibers such as carbon fibers. it can. The organic polymer compound fired body is obtained by firing an organic polymer material such as phenol resin or furan resin at an appropriate temperature of 500 ° C. or higher in an inert gas or vacuum. Coke includes petroleum coke and pitch coke. Carbon black includes acetylene black. Such a carbon material is very effective as a negative electrode active material because of its high energy density per unit volume. Moreover, you may use alkali metals, such as lithium and sodium, and the alloy containing them as a negative electrode active material.

  Examples of the binder include polyvinylidene fluoride, polyvinyl pyridine, and polytetrafluoroethylene, which are used for a negative electrode mixture of a general nonaqueous electrolyte battery.

  The negative electrode 24 is electrically connected to a negative electrode lead 28 formed of, for example, nickel or the like in a strip shape. In this negative electrode lead 28, the negative electrode active material layer 16 is formed in accordance with the exposed part of the negative electrode current collector 24 a provided at one end in the longitudinal direction of the negative electrode 24 (for example, the end on the outer peripheral side), that is, the width of the negative electrode lead 28. Instead, the negative electrode current collector 24a is joined to the exposed portion by resistance welding, ultrasonic welding, or the like. The negative electrode lead 28 is provided with one end extending in the same direction as the positive electrode lead 27 from the width direction of the negative electrode 24.

  The gel electrolyte 25 is an electrolyte obtained by mixing a polymer material, an electrolytic solution, and an electrolyte salt into a gel. A polymer material having a property compatible with the electrolytic solution is used. Examples of such a polymer material include silicon gel, acrylic gel, acrylonitrile gel, polyphosphazene-modified polymer, polyethylene oxide, and composite materials, cross-linked polymers, modified polymers, and the like, or polymer materials such as fluorine-based polymers. And various mixtures thereof.

  As the electrolytic solution, the above-described polymer material can be dispersed, and as the aprotic solvent, for example, ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), or the like is used.

As electrolyte salt, what has a property compatible with electrolyte solution is used. Examples of such electrolyte salts include LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAsF ₆ , LiB (C ₆ H ₅ ) ₄ , LiCF ₃ SO ₃ , LiCH ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiSbF. ₆ , LiClO ₄ , LiCl, LiBr, etc., and any one or a combination of these may be used. In particular, LiPF ₆ or LiBF ₄ having a stable redox potential is used. The gel electrolyte 25 having such a configuration is formed by applying an electrolytic solution containing a polymer material and an electrolyte salt on both the main surfaces of the positive electrode 23 and the negative electrode 24 described above, and then solidifying.

  The separator 17 separates the positive electrode 23 and the negative electrode 24 in order to prevent the above-described positive electrode 23 and the negative electrode 24 from being short-circuited. The separator 17 is made of a known material that is usually used as an insulating porous film of this type of nonaqueous electrolyte battery, for example, a polymer film such as polypropylene or polyethylene.

  The packaging material 22 enclosing the battery element 21 described above is made of a laminate film in which a resin film and a metal foil are laminated and bonded together. Among these, as the resin film, an organic material such as polyethylene, polypropylene, modified polyethylene, modified polypropylene and copolymers thereof, polyolefin resin and the like, which shows adhesion to the positive electrode lead 27 and the negative electrode lead 28 and has excellent airtightness. Resin material is used. On the other hand, for example, aluminum, stainless steel, nickel, iron or the like is used for the metal foil.

  And this exterior material 22 pinches | interposes the battery element 21, and an outer edge part is bonded together along the external shape of the battery element 21, and the battery element 21 is sealed. At this time, the exterior material 22 has a resin film as an inner surface, and among the bonding surfaces 6a, 6b, and 6c bonded by thermal fusion, the positive electrode lead 27 and the negative electrode lead 28 are formed between the bonding surfaces 6a. It shall be in the state pulled out.

  In order to further improve the adhesion between the exterior material 22 and the positive electrode lead 27 and the negative electrode lead 28 between the bonded exterior materials 22, the contact portion between the positive electrode lead 27 and the negative electrode lead 28 and the exterior material 22 is provided. A resin piece 29 to be melted by thermal welding is provided. As the resin piece 29, a material having a heat welding property to the positive electrode lead 27 and the negative electrode lead 28, for example, a polyolefin resin such as polyethylene, polypropylene, modified polyethylene, and modified polypropylene, and a copolymer thereof can be used. As described above, the lithium ion secondary battery 2 as shown in FIG. 3 is configured.

  As shown in FIGS. 2 and 6, the control board 3 connected to the battery described above has substantially the same length as the short side of the lithium ion secondary battery 2 and is a board 31 made of a substantially rectangular plate. And a PTC element 32 as a control element provided on one surface of the substrate 31, and controls the current to the lithium ion secondary battery 2.

  The substrate 31 is provided with a PTC element 32 on one surface and an external terminal 33 connected to an external power source on the other surface. The PTC element 32 and the external terminal 33 are electrically connected to each other. Pattern wiring 34 and via hole 35 to be formed are formed. As the substrate 31, a flexible substrate, a rigid substrate, or the like can be used. In addition to the PTC element 32 described later, a protective circuit for protecting the lithium ion secondary battery 2 is formed on the substrate 31.

  The PTC element 32 provided on the substrate 31 is surface-mounted on one surface of the substrate 31, and a resin layer 36 made of a mixture of a crystalline resin such as polyethylene and conductive particles such as carbon black, and this resin It comprises electrode plates 37a and 37b formed so as to sandwich the layer 36. In the PTC element 32, an electrode plate 37 a formed between the resin layer 36 and the substrate 31 is connected to the pattern wiring 34 formed on the substrate 31 by soldering or the like, and is electrically connected to the pattern wiring 34. It is connected. The PTC element 32 is electrically connected to the lithium ion secondary battery 2 by connecting the electrode plate 37 b formed on the resin layer 36 and one of the positive electrode lead 27 or the negative electrode lead 28 of the lithium ion secondary battery 2. Connected.

  Specifically, the electrical connection between the PTC element 32 and the lithium ion secondary battery 2 is such that the positive electrode lead 27 and the negative electrode which are lead terminals of the lithium ion secondary battery 2 are provided on the surface of the electrode plate 37b facing the resin layer 36. One end of the lead 28, for example, as shown in FIG. The connection between the negative electrode lead 28 and the PTC element 32 is not particularly limited. For example, a welding method such as spot welding or a connection method such as soldering is used.

  In the case where the electrode plates 37a and 37b and the lead terminals are made of different metals, a connection layer made of a conductive metal such as Ni is soldered on the PTC element 32 or a portion where the lead terminal on the PTC element 32 is connected. The lead terminal may be connected to the connection layer. By providing the connection layer on the PTC element 32 in this way, the connection reliability between the PTC element 32 and the negative electrode lead 28 is improved. Further, a plurality of PTC elements 32 may be formed on the substrate 31, and the positive electrode lead 27 and the negative electrode lead 28 may be directly connected to different PTC elements 32.

  In addition, the PTC element 32 is used when an excessive current flows through the lithium ion secondary battery 2, when a large current flows from the lithium ion secondary battery 2 due to an external short circuit, or when the temperature of the lithium ion secondary battery 2 is high. Control is performed so that the current flowing from the lithium ion secondary battery 2 becomes smaller when the temperature becomes higher than a predetermined temperature. This is because when the overcurrent flows through the lithium ion secondary battery 2 or when the lithium ion secondary battery 2 generates excessive heat, the distance between the conductive particles of the resin layer 36 increases, and the electric resistance of the PTC element 32 increases. Rises and the current flowing through the lithium ion secondary battery 2 decreases. When the current flowing through the lithium ion secondary battery 2 is reduced and the temperature of the lithium ion secondary battery 2 is lowered to a predetermined temperature, the PTC element 32 reduces the distance between the conductive particles of the resin layer 36 and the electric resistance is reduced. The current is reduced, and the current flows through the lithium ion secondary battery 2 again.

  As described above, by directly connecting the positive electrode lead 27 or the negative electrode lead 28 to the PTC element 32, a relay tab conventionally used between the PTC element 32 and the positive electrode lead 27 or the negative electrode lead 28 is not required. Therefore, the connecting portion is simplified, and the battery pack 1 can be reduced in size and weight.

  Further, by directly connecting the positive electrode lead 27 or the negative electrode lead 28 to the PTC element 32, the electric resistance between the lithium ion secondary battery 2 and the PTC element 32 is reduced, so that electric conductivity and thermal conductivity are improved. It becomes favorable and the control with respect to the lithium ion secondary battery 2 of the PTC element 32 is improved. Further, when the battery pack 1 is formed, the PTC element 32 is brought into contact with the lithium ion secondary battery 2 in the battery case 4 or arranged near the side surface of the lithium ion secondary battery 2, so that the lithium ion secondary battery is formed. There is no need to facilitate the transfer of heat from the battery 2. Thereby, since the control board 3 can be accommodated in the battery case 4 without limiting the position of the control board 3 in the battery case 4, the external terminal 33 provided on the control board 3 is matched to the use of the battery pack 1. The battery case 4 can be exposed to the outside.

  Further, in the control substrate 3, for example, when a material obtained by adding a lithium composite oxide or the like and a compound having an olivine structure to the positive electrode active material of the positive electrode 23 of the lithium ion secondary battery 2 is used, Since the overcharge safety and overdischarge durability of the secondary battery 2 are improved, a protection circuit for protecting the lithium ion secondary battery 2 from overcharge and overdischarge can be omitted. Thereby, in the battery pack 1, since electrical resistance can be made small, the load characteristic and low temperature characteristic as a pack of the lithium ion secondary battery 2 improve.

  The battery case 4 is made of a plastic case, and as shown in FIG. 2, the upper case 4a and the lower case 4b, each having a substantially flat box shape, are brought into contact with each other, so that the lithium ion secondary battery 2 and the control board 3 are contained therein. A storage space for storing the space is formed. A concave portion 41 to which the control board 3 is fixed is provided at an end portion in the longitudinal direction of the lower case 4a, and an opening hole 42 that is opened to face the external terminal 33 provided on the control board 3 to the outside. Is provided at approximately the center.

  In the above-described battery pack 1, the positive electrode lead 27 or the negative electrode lead 28 of the lithium ion secondary battery 2 is directly connected to the PTC element 32, so that the relay is connected between the PTC element 32 and the positive electrode lead 27 or the negative electrode lead 28. Since it is not necessary to use a tab, the entire battery pack 1 is reduced in size and weight.

  In the battery pack 1, since the positive electrode lead 27 or the negative electrode lead 28 is directly connected to the PTC element 32, the electrical resistance between the lithium ion secondary battery 2 and the control board 3 is reduced. The electric conductivity and thermal conductivity of the lithium ion secondary battery 2 are improved. Thus, in the battery pack 1, the PTC element 32 can be controlled with respect to the lithium ion secondary battery 2 without bringing the PTC element 32 into contact with the lithium ion secondary battery 2 or arranging the PTC element 32 near the lithium ion secondary battery 2. Can be improved. Therefore, in the battery pack 1, the control board 3 can be accommodated in the battery case 4 without limiting the position of the control board 3 in the battery case 4, and thus the external terminals 33 provided on the control board 3 are provided. The battery case 1 can be exposed to the outside according to the use of the battery pack 1.

  Further, in the battery pack 1, by using a positive electrode active material of the positive electrode 23 of the lithium ion secondary battery 2 to which a compound having an olivine structure is added, the overcharge safety of the lithium ion secondary battery 2 by the positive electrode 23 is achieved. And overdischarge durability is improved. Thereby, in the battery pack 1, since the protection circuit provided in the control board 3 can be omitted and the electric resistance can be reduced, the load characteristic and the low temperature special advantage can be obtained as a pack of the lithium ion secondary battery 2. improves.

  Next, a method for manufacturing the battery pack 1 described above will be described. First, the positive electrode active material layer 23b is formed on both surfaces of the positive electrode current collector 23a, and the positive electrode 23 is manufactured. Specifically, in the positive electrode 23, a positive electrode mixture obtained by mixing a positive electrode active material and a binder is removed from a portion where a positive electrode lead 27 of a metal foil such as an aluminum foil that becomes the positive electrode current collector 23a is connected. The positive electrode active material layer 23b is formed on both surfaces of the positive electrode current collector 23a by applying uniformly on both surfaces and drying. As the binder for the positive electrode mixture, known binders can be used, and known additives and the like can be added to the positive electrode mixture. Moreover, the positive electrode active material layer 23b can also be formed using techniques, such as cast application | coating and sintering.

  Next, the negative electrode active material layer 24b is formed on both surfaces of the negative electrode current collector 24a, and the negative electrode 24 is manufactured. Specifically, the negative electrode 24 has a negative electrode mixture in which a negative electrode active material and a binder are mixed, except for a portion where a negative electrode lead 28 of a metal foil such as a copper foil that becomes the negative electrode current collector 24a is connected. The negative electrode active material layer 24b is formed on the negative electrode current collector 24a by being uniformly applied and dried. As the binder of the negative electrode mixture, a known binder can be used, and a known additive or the like can be added to the negative electrode mixture. Moreover, the negative electrode active material layer 24b can also be formed using techniques, such as cast application | coating and sintering.

  The gel electrolyte 25 includes a gel electrolyte formed by adding a non-aqueous electrolyte as a plasticizer to a matrix polymer, and a polymer solid electrolyte obtained by dissolving an electrolyte salt in the polymer. These include the positive electrode 23 and the negative electrode described above. It is formed by applying a nonaqueous electrolytic solution containing a polymer compound and an electrolyte salt on both main surfaces of 24 and then gelling.

  Next, the positive electrode lead 27 is ultrasonically welded to one end of the positive electrode current collector 23a, and the negative electrode lead 28 is ultrasonically welded to one end of the negative electrode current collector 24a.

  Next, the separator 17 is interposed between the positive electrode 23 and the negative electrode 24 produced as described above, and the gel electrolyte 25 formed on each of the positive electrode 23 and the negative electrode 24 is opposed to the positive electrode lead 27 and the negative electrode lead 28. Are laminated so as to be led out from one end and wound to produce a flat battery element 21.

  Next, the lithium ion secondary battery 2 and the PTC element 32 of the control board 3 are connected, and the lithium ion secondary battery 2 and the control board 3 are electrically connected. Either one of the positive electrode lead 27 or the negative electrode lead 28 of the lithium ion secondary battery 2, for example, as shown in FIG. 6, the negative electrode lead 28 is welded to the PTC element 32 by spot welding, leather welding, soldering, ultrasonic wave, or the like. Thus, the end of the negative electrode lead 28 is directly connected to the electrode plate 36 b on the PTC element 32. Note that a Ni tab may be soldered on the PTC element 32, and the PTC element 32 may be connected to the Ni tab. In addition, when a lithium composite oxide and a compound having an olivine structure are used as the positive electrode active material, it is not necessary to provide a protective circuit for controlling the lithium ion secondary battery 2 on the substrate 31.

  Next, after the lithium ion secondary battery 2 and the control board 3 are accommodated between the upper half 4a and the lower half 4b of the battery case 4, the upper half 4a and the lower half 4b are joined together, and the control board 3 The battery pack 1 as shown in FIG. 1 is configured by facing the external terminals 33 mounted on the outside through the opening holes 42.

  In the method of manufacturing the battery pack 1 described above, when the lithium ion secondary battery 2 and the control board 3 are connected, the PTC element 32 and the positive electrode lead 28 are directly connected to the PTC element 32 by connecting the positive electrode lead 27 or the negative electrode lead 28 directly. Since the connection between the lead 27 or the negative electrode lead 28 is simplified, the battery pack 1 that is reduced in size and weight can be obtained.

  Further, in this method of manufacturing the battery pack 1, by directly connecting the positive electrode lead 27 or the negative electrode lead 28 to the PTC element 32, the electric resistance between the lithium ion secondary battery 2 and the control board 3 is reduced, and the lithium ion The electrical conductivity and thermal conductivity from the secondary battery 2 to the PTC element 32 are improved. Thereby, in the manufacturing method of the battery pack 1, the PTC element 32 is not brought into contact with the lithium ion secondary battery 2 or disposed near the lithium ion secondary battery 2, and the lithium ion secondary battery 2 of the PTC element 32. The control over can be improved. Therefore, in the manufacturing method of the battery pack 1, the control board 3 is accommodated in the battery case 4 without limiting the position of the control board 3 in the battery case 4, and the external terminals 33 provided on the control board 3 are connected to the battery. The battery case 4 can be exposed to the outside according to the usage of the pack 1.

Moreover, in the manufacturing method of the battery pack 1 mentioned above, since the overcharge safety | security and overdischarge durability of the battery pack 1 improve by adding the compound which has olivine structure to the positive electrode active material of the positive electrode 23, control board | substrate 3, a protection circuit for protecting the lithium ion secondary battery 2 can be omitted. Thereby, in the manufacturing method of this battery pack 1, since the electrical resistance of the whole battery pack 1 can be made small, the load characteristic as a pack of the lithium ion secondary battery 2 and the case where the protection circuit is used together are reduced. In the battery pack 1 described above, the lithium ion secondary battery 2 and the control board 3 are housed in the battery case 4, but the present invention is not limited to this. For example, FIG. A battery pack 50 as shown may be used. In the following description of the battery pack 50, the same parts as those of the above-described battery pack 1 are not described and are denoted by the same reference numerals in the drawings.

  As shown in FIGS. 7 and 8, the battery pack 50 includes a lithium ion secondary battery 51, a substantially rectangular frame 52 surrounding the lithium ion secondary battery 51 and the control board 3, and a control board within the frame 52. 3, and an exterior material 54 that covers a region where the lithium ion secondary battery 51 is exposed from the frame 52.

  The lithium ion secondary battery 51 is a battery element 21 that can be doped / undoped with lithium ions, a first package 61 that covers the battery element 21, and a second that also serves as an exterior material for the battery pack 50. The package body 62 is provided.

  As shown in FIG. 9, the first package 61 that stores the battery element 21 has a substantially rectangular shape, and a storage recess 63 in which the battery element 21 is stored is formed in advance. A joining piece 64 to be joined to a second packaging body 62 described later is provided around the storage recess 63. Further, the first packaging body 61 has notches 65 formed at both ends of the joining pieces 64 on both short sides.

  The first package 61 has a laminated structure in which a polypropylene (PP) layer, an aluminum (Al) layer, and a nylon layer (Ny) are laminated in this order from the inside. Here, the aluminum layer prevents moisture from entering the inside. The polypropylene layer prevents deterioration of the solid electrolyte 16 and serves as a joint surface when the first package 61 is joined to the second package 62 or to the frame 52. That is, at the time of joining to the second packaging body 62 or joining to the frame 52, the polypropylene layer is opposed to the polypropylene layer or the frame 52 of the second packaging body 62 and heat-sealed at about 170 ° C. To join. The nylon layer gives the first package 61 a certain strength. In addition, the structure of the 1st package 61 is not limited to this, The laminate film etc. which have various materials and laminated structure can be used. Examples of the constituent material of the first package 61 include aluminum, polyethylene terephthalate (PET), non-axially oriented polypropylene (CPP), acid-modified polypropylene, ionomer, ON, and the like. Further, the joining method is not limited to thermal welding.

  As shown in FIG. 9, the second package 62 is formed in a substantially rectangular shape and covers the surface exposed to the outside of the battery element 21 stored in the storage recess 63 of the first package 61. It has the part 67 and the junction part 68 joined to the joining piece 64 of the 1st package 61. FIG.

  The covering portion 67 has substantially the same area as the surface exposed to the outside of the battery element 21. The joining portion 68 is formed larger in the long side direction and the short side direction than the joining piece 64 of the first packaging body 61. A portion of the joining portion 68 that is formed larger than the joining piece 64 of the first package 61 serves as a glue margin portion 68 a when joined to the side wall portion 52 c of the frame 52. As for this glue margin part 68a, the polypropylene layer is exposed to the 1st package 61 side. Further, similarly to the first package 61, the second package 62 is provided with notches 69 at both ends of one short side.

  The second package 62 configured as described above is joined to the first package 61 to cover the exposed surface of the battery element 21 and to form one main surface of the battery pack 50. . In addition, the connecting portion between the joint portion 68 of the second package 62 and the joint piece 64 of the first package 61 has a side wall portion 52c of the frame 52 and an adhesive margin portion 68a of the second package 62. By joining, three side surfaces of the battery pack 50 are formed.

  A positive electrode lead 27 and a negative electrode lead 28 that are led out from one end of the battery element 21 are interposed between the first package 61 and the second package 62 to be bonded together. Therefore, in order to improve the adhesion between the positive electrode lead 27 and the negative electrode lead 28 between the first package 61 and the second package 62, the positive electrode lead 27 and the negative electrode lead 28, A resin piece 36 to be melted by thermal fusion is provided at a contact portion between the package body 61 and the second package body 62.

  The second packaging body 62 described above includes a resin layer and a metal layer, and has a laminated structure in which a polypropylene (PP) layer, an aluminum layer (Al), and a nylon (Ny) layer are laminated in this order from the inside. Laminated film. The polypropylene layer serves as a joining surface when joining to the side wall 52c of the frame 52. The aluminum layer maintains the airtightness of the battery pack 50. The nylon layer has a strength that can withstand external impacts such as piercing and maintains insulation between the outside of the battery pack 50 and the aluminum layer.

  As in the battery pack 1 described above, the lithium ion secondary battery 51 having the above-described configuration directly connects one of the positive electrode lead 27 or the negative electrode lead 28 to the PTC element 32 provided on the control board 3 and the other. By being connected to the wiring pattern 44, it is electrically connected to the control board 3.

  As shown in FIGS. 8 and 10, the frame 52 that houses the lithium ion secondary battery 51 and the control board 3 is a frame-shaped member having a size that matches the outer shape of the battery element 21, and leads the battery element 21. Front wall portion 52a arranged on the side from which the terminal is led out, rear wall portion 52b arranged on the short side opposite to the lead terminal of battery element 21, and side wall portion arranged on the side surface of battery element 21 52c and the upper wall part 52d. When the control board 3 is fixed inside the frame 52, an opening hole 70 for exposing the external terminal 33 provided on the control board 3 to the outside and a fixing member 53 described later are formed in the front wall portion 52a. An engaging recess 71 to be locked and a recess 72 for adjusting to the size of the control board 3 disposed inside are provided at both upper ends of the outside.

  Moreover, as shown in FIG.10 and FIG.11, the edge part of the joining piece 64 of the 1st package 61 is engaged with the lower end side of the rear wall part 52b and the side wall part 52c of the flame | frame 52. A stepped portion 74 is provided, and further, a second stepped portion 75 is provided above the first stepped portion 74 and the end of the joint portion 68 of the second package 62 is engaged. In addition, a third stepped portion 76 with which the end portion of the exterior material 54 is engaged is provided over the entire circumference of the upper wall portion 52d of the frame 52.

  Specifically, the first stepped portion 74 has a width toward the inside of the frame 52 and is formed to be cut out toward the lower side, and the width of the cutout is engaged with the first packaging to be engaged. The width is substantially the same as the thickness of the body 61. The second stepped portion 75 is formed by being cut out so as to be continuous with the first stepped portion 74, and this cutout has a width substantially the same as the thickness of the second packaging body 62 to be engaged with the frame. Cut out toward the inside of 52. The third step portion 76 is provided with a step so that the entire circumference of the upper wall portion 52d is open to the upper end.

  In the first step portion 74 and the second step portion 75, the end portion of the joining piece 64 of the first package 61 is engaged with the first step portion 74, and the first step portion 74 and the second step portion 75 are located above the first step portion 74. The end portions of the joint portion 68 of the second package 62 are engaged by the two step portions 75. Thereby, the position of the end portion of the joining piece 64 of the first packaging body 61 and the end portion of the joining portion 68 of the second packaging body 62 are shifted on the side wall portion 52c. It is prevented that the conductive metal layers constituting the part are in contact with each other and short-circuited.

  Further, since the end portion of the outer packaging material 54 and the joint portion 68 of the second package 62 engaged with the second stepped portion 75 are separated by the third stepped portion 76, the outer packaging material 54 is separated. And the short circuit between the 2nd package 62 is prevented.

  Further, by providing the first stepped portion 74 to the third stepped portion 76 in the frame 52, the end of the first package 61 and the end of the second package 62 are not exposed to the outside. Therefore, the battery pack 50 is prevented from being damaged outside by the end portions of these packaging bodies.

  Further, by disposing the frame 52 around the lithium ion secondary battery 51 and the control board 3, the lithium ion secondary battery 51 and the control board 3 can be protected from an impact such as dropping. The frame 52 can be made of various plastic materials. In particular, considering the bonding with the packaging body, the first packaging body 61, the second packaging body 62, and the same material as polypropylene used for the exterior material 54 described later, that is, polypropylene, or a melting point equivalent to that of polypropylene. Materials are preferred.

  As shown in FIG. 8, the fixing member 53 includes a support portion 81 that supports the control board 3, and an engagement recess portion 71 that is provided at both outer ends of the support portion 81 and is provided in the front wall portion 52 a of the frame 52. The engaging projection 82 is engaged. The support portion 81 is formed in a substantially U-shape, and is supported by sandwiching both ends of the control board 3. When the engaging protrusion 82 is disposed in the frame 52, the engaging protrusion 82 engages with an engaging recess 71 provided in the front wall portion 52 a of the frame 52 and is fixed in the frame 52. Therefore, the fixing member 53 is disposed in the frame 52 together with the control board 3, thereby fixing the control board 3 with the support portion 81 material and the engaging protrusion 82.

  As shown in FIGS. 7 and 8, the exterior material 54 is formed in a substantially rectangular shape, and covers the housing recess 63 of the first packaging body 61 from above the frame 52. The exterior material 54 is formed with a notch 91 on one short side so as to match the recess 72 formed in the front wall 52 a of the frame 52. The exterior material 54 is joined to the third step and the butting frame 52 at an end portion thereof to cover the housing recess 63 of the first packaging body 61 and to form the other main surface of the battery pack 50.

  In the battery pack 50 described above, the positive electrode lead 27 or the negative electrode lead 28 of the lithium ion secondary battery 51 is directly connected to the PTC element 32, and the lithium ion secondary battery 51 and the control board 3 are surrounded by the frame 52. By wrapping with the packaging body 62 and the exterior material 54, further reduction in size and weight is achieved.

  Further, in the battery pack 50, since the positive electrode lead 27 or the negative electrode lead 28 is directly connected to the PTC element 32, the electric resistance between the lithium ion secondary battery 51 and the PTC element 32 is reduced. The electric conductivity and thermal conductivity between the battery 51 and the PTC element 32 are improved. Thereby, in the battery pack 50, the PTC element 32 is controlled to the lithium ion secondary battery 51 without bringing the PTC element 32 into contact with the lithium ion secondary battery 51 or arranging the PTC element 32 on the side surface of the lithium ion secondary battery 51. Can be improved.

  Furthermore, in the battery pack 50, by adding a compound having an olivine structure to the positive electrode active material of the positive electrode 14, the overcharge safety and the overdischarge durability of the lithium ion secondary battery 51 can be improved. A protection circuit for protecting the lithium ion secondary battery 51 provided on the substrate 3 can be omitted. Thereby, in the battery pack 50, electric resistance becomes small and the load characteristic and low temperature characteristic as a pack of the lithium ion secondary battery 51 improve compared with the case where the protection circuit is used together.

  Next, a method for manufacturing the battery pack 50 described above will be described. First, the battery element 21 is manufactured by the same method as the battery element 21 of the battery pack 1 described above, and the lithium ion secondary battery 51 is manufactured.

  Specifically, as shown by an arrow A in FIG. 9, the battery element 21 is stored in the storage recess 63 of the first package 61. At this time, the positive electrode lead 27 and the negative electrode lead 28 of the battery element 21 are led out to the short side of the first package 61.

  Next, as shown in the direction of arrow B in FIG. 9, the second package body from the side where the battery element 21 is exposed so that the polypropylene layer of the second package body 62 is on the first package body 61 side. 62 is overlaid on the first packaging body 61 to cover the surface exposed to the outside of the battery element 21 housed in the housing recess 63 of the first packaging body 61. And the 1st package 61 and the 2nd package 62 are joined. For the joining, the polypropylene layer of the joining piece 64 of the first packaging body 61 and the polypropylene layer of the joining portion 68 of the second packaging body 62 are approximately separated in the four directions around the battery element 21 that are housed in the housing recess 63. It is performed by heat welding at 170 ° C.

  At this time, as shown in FIG. 12, the decompression pump 100 is used to perform decompression simultaneously with the joining. Thereby, the battery element 21 is covered and sealed with the first packaging body 61 and the second packaging body 62. At this time, the positive electrode lead 21 and the negative electrode lead 22 of the battery element 21 are sandwiched between the joining surfaces of the first packaging body 61 and the second packaging body 62 and led out of the packaging body. It becomes.

  Here, during decompression, the inside of the storage recess 63 of the first package 61 is sucked. Accordingly, as shown in FIG. 12, the battery element 21 stored in the storage recess 63 is drawn by the first packaging body 61, the bottom surface side of the storage recess 63 is small, and the second packaging body 62 is joined. The side which is larger is substantially trapezoidal in cross section, and the volume of the lithium ion secondary battery 51 is reduced.

  Next, the lead terminal of the lithium ion secondary battery 51 and the PTC element 32 of the control board 3 are directly connected by the same method as the battery pack 1 described above.

  Next, as shown in FIG. 8, the lithium ion secondary battery 51 and the control board 3 are disposed in the frame 52. Next, as shown in the direction of arrow C in FIG. 8, the control board 3 is bent so that the side surfaces of the PTC element 32 and the battery element 21 face each other. Next, as shown in the direction of arrow D in FIG. 8, the frame 52 is disposed from the first packaging body 61 side, and the fixing member 53 that supports the control substrate 3 to which the positive electrode lead 21 and the negative electrode lead 22 are connected. Is provided on the front wall portion 52 a of the frame 52. At this time, the control board 3 is provided with the fixing member 53 in the frame 52 so that the engaging protrusion 82 of the fixing member 53 and the engaging recess 71 formed in the frame 52 are engaged. It is fixed in the frame 52. Further, by disposing the frame 52 around the battery element 21, the mechanical strength equivalent to that in the case of using the plastic case and the reliability of the terminal can be maintained without storing the battery element 21 in the plastic case. Can do.

  Next, the joining portion of the joining piece 64 of the first packaging body 61 and the joining portion 68 of the second packaging body 62 is bent as shown in the direction of arrow E in FIG. The frame 52 is disposed along the side wall 52c and the rear wall 52b. Next, the adhesive margin 68a of the second package 62 is thermally welded to the side wall 52c and the rear wall 52b of the frame 52. By this welding, as shown in FIGS. 8 and 11, the joining piece 64 of the first package 61 and the first stepped portion 74 are brought into contact with each other, and the second package 62 and the second stepped portion are contacted. 75 is brought into contact with each other, and the side surface of the battery pack 50 is formed.

  Next, as shown in the direction of arrow F in FIG. 8, the frame 52 disposed around the storage recess 63 of the first packaging body 61 so that the polypropylene layer of the exterior material 54 is on the storage recess 63 side. An exterior material 54 is disposed on the upper wall portion 52c. And the polypropylene layer of the exterior material 54 and the upper wall part 52d of the flame | frame 52 are heat-welded at 170 degreeC. As a result of the welding, the end portion of the exterior material 54 is brought into contact with the third stepped portion 76 provided in the frame 52, the upper wall portion 52c of the frame 52 is flush, and the upper surface of the battery pack 50 is formed. A battery pack 50 as shown in FIG. 7 is completed.

  As described above, in the method of manufacturing the battery pack 50, the positive electrode lead 27 or the negative electrode lead 28 of the lithium ion secondary battery 51 is directly connected to the PTC element 32, and the lithium ion secondary battery 51 and the control board 3 are connected to the frame 52. The battery pack 50 that is further reduced in size and weight is obtained by wrapping with the second package 62 and the exterior material 54.

  Moreover, in the manufacturing method of the battery pack 50, the PTC element 32 and the positive electrode lead 27 or the negative electrode lead 28 of the lithium ion secondary battery 51 are directly connected, so that the connection can be made more than in the case where a relay tab is used as in the prior art. Since the number of locations is reduced and the electrical resistance between the lithium ion secondary battery 51 and the PTC element 32 is reduced, the electrical conductivity and thermal conductivity between the lithium ion secondary battery 51 and the PTC element 32 are improved. Thereby, in the battery pack 50, the PTC element 32 is controlled with respect to the lithium ion secondary battery 51 without bringing the PTC element 32 into contact with the lithium ion secondary battery 51 or arranging the PTC element 32 on the side surface of the lithium ion secondary battery 51. Can be improved.

  Furthermore, in the manufacturing method of the battery pack 50, the lithium ion secondary battery 51 is protected from the positive electrode by using the positive electrode active material of the positive electrode 14 to which a compound having an olivine structure is added. The protection circuit currently provided can be omitted, and the electric resistance of the battery pack 50 can be reduced. Thereby, in the manufacturing method of the battery pack 50, the load characteristic and low temperature characteristic as a pack of the lithium ion secondary battery 51 improve compared with the case where the protection circuit is used together.

It is a perspective view of the battery pack to which the present invention is applied. It is a disassembled perspective view of the battery pack. It is a perspective view of a battery. It is sectional drawing in line segment XX in FIG. It is sectional drawing in the line segment YY in FIG. It is sectional drawing which shows the connection part of a positive electrode lead and a negative electrode lead, and a control board. It is a perspective view of the other battery pack to which this invention is applied. It is a disassembled perspective view of the battery pack. It is a perspective view which shows a mode that a battery is covered with a 1st package and a 2nd package. It is a perspective view of the flame | frame used for the battery pack. It is sectional drawing in line segment ZZ in FIG. It is sectional drawing which shows the pressure reduction state of an accommodation recessed part.

Explanation of symbols

  1 battery pack, 2 lithium ion secondary battery, 3 control board, 4 battery case, 31 board, 32 PTC element, 33 external terminal,

Claims (6)

A battery element having a battery element laminated via a separator between a positive electrode and a negative electrode, and a battery in which a lead terminal is derived from each of the positive electrode and the negative electrode,
A board and a control board that has at least one or more surface-mounted control elements on the board and controls a current with respect to the battery;
A power supply apparatus in which at least one of lead terminals respectively led out from the positive electrode and the negative electrode is directly connected to one control element.   The power supply apparatus according to claim 1, wherein the control element is a PTC element.   The power supply device according to claim 1, wherein the battery is a polymer battery.   The power supply device according to claim 1, wherein the positive electrode has a lithium composite oxide as a positive electrode active material, and the negative electrode has a carbonaceous material as a negative electrode active material.   The power supply device according to claim 4, wherein a compound having an olivine structure is added to the positive electrode active material. A method of connecting a battery and a substrate,
The battery has a battery element laminated via a separator between a positive electrode and a negative electrode, and lead terminals are led out from the positive electrode and the negative electrode,
A method of connecting a battery and a substrate, wherein at least one of lead terminals derived from each of the positive electrode and the negative electrode is directly connected to a control element surface-mounted on at least one or more on the substrate.

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