JP2007095417A - Battery pack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a battery pack in which USB (Universal Serial Bus) terminal mounting electronic equipment such as a portable audio player equipped with a USB plug capable of charging only by USB bus power can be easily charged outdoors or the like. <P>SOLUTION: This is the battery pack 10 in which the USB plug 11 that has a secondary battery, a charge control circuit 2, and a discharge control circuit 26 or the like inside, and that is connected to the charge control circuit, and a USB receptacle 12 that is connected to the discharge control circuit are installed at a sheath body. In charging the battery pack, the USB plug of the battery pack is plugged into a personal computer. Moreover, when the USB terminal mounting electronic equipment is charged at a place such as outdoors wherein the USB terminal of the personal computer cannot be obtained easily, the USB plug of the USB terminal mounting electronic equipment is connected to the USB receptacle of the battery pack. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a battery pack, and more particularly to a battery pack having a general-purpose serious bus (USB) interface.

  Many of the electronic devices currently used have a built-in secondary battery, and charging is often performed by connecting the electronic device directly to a charger or the like. Most of these chargers are connected to a commercial power source to charge electronic devices, and the electronic devices can be electrically installed by being placed in an insertion port of a charging adapter or a dedicated charger called a cradle. Connected to each other.

  On the other hand, in recent years, portable audio players equipped with a USB (Universal Serial Bus) connector and capable of only USB bus power charging have become widespread with the miniaturization of the body size of portable audio players with built-in memory. As shown in FIG. 1A, such a portable audio player 2 is charged by being inserted into a USB port mounted on the personal computer 1 at the time of charging.

  In USB, various peripheral devices are basically connected around a single personal computer (host). At this time, in order to prevent a device configuration error in advance, a so-called upstream-side personal computer side uses a flat-shaped connector called Series A, and a so-called downstream side peripheral device side has a rectangular series B. A connector called is used.

  Both ends of the USB cable are a series A plug (A plug) and a series B plug (B plug), and a personal computer is provided with a series A socket (A receptacle) for inserting the plugs. The peripheral device is provided with a series B insertion port (B receptacle). For this reason, the portable audio player is provided with an A plug and is inserted as shown in FIG. 1A to charge and transfer data, or, for example, as shown in FIG. 1B, an AC power adapter 3 having a USB connector. It is also possible to perform charging only.

The following Patent Document 1 describes a charging device that charges a secondary battery or a mobile phone by connecting a secondary battery charging holder, a mobile phone charger, or the like to a personal computer. The personal computer is equipped with a device such as an international standard PCI (PC interface) with a built-in charge processing operation program, or a hard disk in which the charge processing operation program is installed, such as a secondary battery or a mobile phone. A predetermined charging operation can be performed on the electronic device in which the secondary battery is incorporated.
JP 2002-27678 A

  In the charging device having such a configuration, it is also possible to perform charging by connecting an electronic device to an interface such as a USB and connecting to a power supply circuit in a personal computer.

  However, at present, electronic devices are often used outdoors for a long time due to downsizing and multifunctionalization of electronic devices, and there are many opportunities to require charging during outdoor use. Portable audio players are no exception and are difficult to charge when the battery runs out outdoors.

  For example, in mobile phones and the like, a large number of simple chargers using a charging connector using a primary battery or a battery pack of a primary battery are commercially available and are relatively easily available. However, it is difficult to obtain a simple charger that charges a portable audio player via a USB connector. Also, a battery pack with a USB terminal that can charge a portable audio player and can be reused by charging itself has not been commercialized.

  Therefore, the present invention is not only capable of easily charging an electronic device capable of USB bus power charging outdoors, but also to extend the usage time in combination with a driving power source and an internal power source of a portable audio player. An object of the present invention is to provide a battery pack with a USB terminal that can also be used as a power source.

  In order to solve the above-described problems, the present invention includes a chargeable / dischargeable secondary battery, a charge control circuit for controlling charge and discharge connected to the secondary battery, and a discharge control circuit. And a USB receptacle connected to the discharge control circuit and a battery pack having a configuration in which the exterior body is provided.

  According to the present invention, the electronic device can be easily carried and the electronic device can be charged via the USB receptacle even in an outdoor place where a USB terminal mounted on a personal computer or the like cannot be obtained. In addition, by mounting a USB plug on the battery pack, it is possible to charge the battery pack without requiring a dedicated charger for the battery pack itself.

  In addition to being used as a charging battery by connecting to a battery pack, it is possible to use it as an operating power source for electronic devices or to extend the usage time in combination with an internal power source.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 2 is an external view of the battery pack 10 to which the present invention is applied. The battery pack 10 has a substantially rectangular parallelepiped shape as a whole, and a USB plug 11 is provided at one end thereof, and a USB receptacle 12 for connecting to an electronic device such as a portable audio player is provided at the other end. It has been. The USB plug 11 is connected to a personal computer when charging the battery pack, and the USB receptacle 12 is connected when the electronic device is connected to the electronic device and used as an operating power source. The battery pack 10 contains a secondary battery and a charge control circuit and a discharge control circuit that control charging and discharging of the battery pack.

  Examples of the secondary battery housed in the battery pack 10 include a cylindrical lithium ion secondary battery. A cylindrical lithium ion secondary battery that can be used in the present invention will be described below.

  In this cylindrical lithium ion secondary battery, for example, a positive electrode and a negative electrode are stacked via a separator and wound to produce a battery element, which is then accommodated in a metal can and further accommodated in a battery pack. is there.

[Positive electrode]
In the positive electrode, a positive electrode active material layer containing a positive electrode active material is formed on both surfaces of a positive electrode current collector. The positive electrode current collector is made of a metal foil such as an aluminum (Al) foil, a nickel (Ni) foil, or a stainless (SUS) foil.

  The positive electrode active material layer includes, for example, a positive electrode active material, a conductive agent, and a binder. The positive electrode active material, the conductive agent, the binder, and the solvent only need to be uniformly dispersed, and the mixing ratio is not limited.

As the positive electrode active material, for example, a composite oxide of lithium and a transition metal mainly composed of LiMO ₂ (wherein M represents one or more transition metals) or an intercalation compound containing lithium is used. As a transition metal constituting these, at least one selected from cobalt (Co), nickel (Ni), manganese (Mn), iron (Fe), aluminum (Al), vanadium (V), and titanium (Ti) is selected. Is done. Li _a MX _b (wherein, M is one selected from the above transition metals, X is selected from S, Se, and PO ₄ , and a and b are integers) can also be used. .

Alternatively, a lithium composite oxide represented by Li _y MIO ₂ or Li _y MII ₂ O ₄ can be used as the positive electrode active material. Such a lithium composite oxide is a particularly preferable material because it can generate a high voltage when used as a positive electrode active material and has an excellent energy density. In these composition formulas, MI represents one or more transition metal elements, and specifically, preferably contains at least one of cobalt and nickel. MII represents one or more transition metal elements, and specifically, manganese (Mn) is preferable. The value of y varies depending on the charge / discharge state of the battery, and is usually in the range of 0.05 to 1.10. Specific examples of such a lithium composite oxide include LiCoO ₂ , LiNiO ₂ , LiNi _z Co _1-z O ₂ (where 0 <z <1), LiMn ₂ O _{4, and the} like.

  As the conductive agent, for example, a carbon material such as carbon black or graphite is used. As the binder, for example, polyvinylidene fluoride, polytetrafluoroethylene, polyvinylidene fluoride, or the like is used. Moreover, as a solvent, N-methyl-2-pyrrolidone (NMP) etc. are used, for example.

  The above-described positive electrode active material, binder, and conductive agent are uniformly mixed to form a positive electrode mixture, and this positive electrode mixture is dispersed in a solvent to form a slurry. Next, this slurry is uniformly applied to both surfaces of the positive electrode current collector by a doctor blade method or the like. Furthermore, the positive electrode active material layer is formed by drying at a high temperature and removing the solvent.

  The positive electrode has one positive electrode terminal connected by spot welding or ultrasonic welding to a substantially central portion in the longitudinal direction of the positive electrode current collector. The positive electrode terminal is preferably a metal foil or a mesh-like one, but there is no problem even if it is not a metal as long as it is electrochemically and chemically stable and can conduct electricity. Examples of the material for the positive electrode terminal include Al. Moreover, the positive electrode terminal welding part on a positive electrode electrical power collector is good also as a positive electrode electrical power collector exposure part which does not form a positive electrode active material layer. In this case, the positive electrode terminal can be easily welded, and the active material layer may be damaged by heat or vibration generated during the positive electrode terminal welding, and the active material layer may fall off, which can be prevented.

[Negative electrode]
In the negative electrode, a negative electrode active material layer containing a negative electrode active material is formed on both surfaces of a negative electrode current collector. The negative electrode current collector is made of a metal foil such as a copper foil, a nickel foil, or a stainless steel foil.

  The negative electrode active material layer includes, for example, a negative electrode active material, a conductive agent if necessary, and a binder. The mixing ratio of the negative electrode active material, the conductive agent, the binder, and the solvent is not limited as in the positive electrode active material.

  As the negative electrode active material, a carbon material that can be doped / undoped with lithium, a crystalline material, and an amorphous metal oxide are used. Specifically, examples of the carbon material that can be doped / undoped with lithium include graphite, non-graphitizable carbon material, graphitizable carbon material, and highly crystalline carbon material with a developed crystal structure. More specifically, pyrolytic carbons, cokes (pitch coke, needle coke, petroleum coke), graphites, glassy carbons, organic polymer compound fired bodies (phenolic resin, furan resin, etc.) at an appropriate temperature. Carbon materials such as those obtained by firing and carbonization), carbon fibers, activated carbon, and the like can be used.

As another negative electrode active material, a metal capable of forming an alloy with lithium, or an alloy compound of such a metal can be given. Specifically, the alloy compound referred to here is M _p M ′ _q Li _r (where M ′ is 1 other than Li element and M element), where M is a metal element capable of forming an alloy with lithium. And p is a numerical value greater than 0, and q and r are numerical values greater than or equal to 0). Further, in the present invention, elements such as B, Si, As and the like, which are semiconductor elements, are also included in the metal element, specifically, Mg, B, Al, Ga, In, Si, Ge, Sn, Pb, Sb. , Bi, Cd, Ag, Zn, Hf, Zr, Y and their alloy compounds, for example, Li-Al, Li-Al-M (wherein M is a group of 12a, 3B, 4B) 1 or more of metal elements), AlSb, CuMgSb, and the like.

Among the elements described above, it is preferable to use elements such as Si and Sn or alloys thereof in addition to the group 3B typical elements, and Si or Si alloys are particularly preferable. Specifically, Si or Si alloy is a compound represented by M _x Si, M _x Sn (wherein M is one or more metal elements excluding Si or Sn), specifically, SiB. 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 the} like.

  As the binder, for example, polyvinylidene fluoride, styrene butadiene rubber or the like is used. Examples of the solvent include N-methyl-2-pyrrolidone and methyl ethyl ketone.

  The above-described negative electrode active material, binder, and conductive agent are uniformly mixed to form a negative electrode mixture, which is dispersed in a solvent to form a slurry. Next, this slurry is uniformly applied to both surfaces of the negative electrode current collector by a doctor blade method or the like. Furthermore, the negative electrode active material layer is formed by drying at a high temperature and removing the solvent.

  The negative electrode has a negative electrode terminal connected to both ends of the current collector by spot welding or ultrasonic welding. This negative electrode terminal is electrochemically and chemically stable, and there is no problem even if it is not a metal as long as it can conduct electricity. Examples of the material for the negative electrode terminal include copper and nickel. Similarly to the positive electrode terminal welded portion, the negative electrode terminal welded portion may be a negative electrode current collector exposed portion, thereby preventing the active material from dropping off during the negative electrode terminal welding.

[Electrolyte]
The electrolytic solution is obtained by dissolving an electrolyte salt in a non-aqueous solvent, and materials generally used for lithium ion batteries can be used. Examples of the non-aqueous solvent include propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, methyl ethyl carbonate, γ-butyrolactone, tetrahydrofuran, 2-dimethoxyethane, 1,3-dioxolane, 4-methyl-1,3-dioxolane. , Diethyl ether, sulfolane, methyl sulfolane, acetonitrile, propionitrile, and the like are preferable, and any one of these or a mixture of two or more thereof can be used.

As the electrolyte salt, one that dissolves in the non-aqueous solvent is used, and a combination of a cation and an anion is used. Alkali metals and alkaline earth metals are used as cations, and Cl ⁻ , Br ⁻ , I ⁻ , SCN ⁻ , ClO ₄ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , CF ₃ SO ₃ ^{− and the} like are used as anions. It is done. Specifically, for example, LiCl, LiClO ₄ , LiAsF ₆ , LiPF ₆ , LiBF ₄ , LiB (C ₆ H ₅ ) ₄ , LiBr, CH ₃ SO ₃ Li, CF ₃ SO ₃ Li, N (CnF _2n + 1SO ₂ ) ₂ Li and the like, and any one of these or a mixture of two or more thereof is used. Among them, it is preferable to mainly use LiPF ₆ . The electrolyte salt concentration is not a problem as long as it can be dissolved in the non-aqueous solvent, but the lithium ion concentration is 0.4 mol / kg or more and 2.0 mol / kg or less with respect to the non-aqueous solvent. A range is preferable.

  Alternatively, a polymer solid electrolyte containing a simple substance or a mixture of conductive polymer compounds or a gel electrolyte containing a swelling solvent may be used. The conductive polymer compound contained in the polymer solid electrolyte or the gel electrolyte is compatible with the electrolytic solution, specifically silicon gel, acrylic gel, acrylonitrile gel, polyphosphazene modified polymer, polyethylene oxide, Polypropylene oxide, fluorine-based polymers, composite polymers, cross-linked polymers, modified polymers, and the like thereof can be used. Examples of the fluorine-based polymer include poly (vinylidene fluoride), poly (vinylidene fluoride-co-hexafluoropropylene), poly (vinylidene fluoride-co-trifluoroethylene), or poly (vinylidene fluoride-co-tetra). Polymer materials such as fluoroethylene) and mixtures thereof are used.

[Separator]
The separator is made of, for example, a porous film made of a polyolefin-based material such as polypropylene (PP) or polyethylene (PE), or a porous film made of an inorganic material such as a ceramic nonwoven fabric. A structure in which a porous film is laminated may be used. Among these, polyethylene and polypropylene porous films are the most effective.

  In general, the thickness of the separator is preferably 5 to 50 μm, more preferably 7 to 30 μm. If the separator is too thick, the amount of the active material filled decreases, the battery capacity decreases, and the ionic conductivity decreases and the current characteristics deteriorate. On the other hand, if the film is too thin, the mechanical strength of the film decreases.

[Production of battery element]
The positive electrode and the negative electrode produced as described above were laminated and wound in the order of the positive electrode, the separator, the negative electrode, and the separator, and the winding edge of the outermost periphery was fixed with a tape to produce a wound battery element.

  Next, the battery element described above is accommodated in a battery can. At this time, the negative electrode terminal lead-out side of the winding surface of the battery element is accommodated so as to be covered with an insulating plate made of an insulating resin. Thereafter, one electrode rod is inserted from the battery element winding center portion, the other electrode rod is disposed outside the bottom surface of the battery can and resistance welding is performed, and the negative electrode terminal is fixed to the bottom surface of the battery can.

  After the negative electrode terminal is welded to the battery can, a center pin is inserted, and an insulating plate is also disposed on the winding surface portion located at the open end of the battery can to inject the electrolyte. Furthermore, the positive terminal is connected to a positive terminal plate provided with a safety valve mechanism and a PTC element inside, and the positive terminal plate is attached by caulking through an insulating sealing gasket, so that the inside of the battery can is sealed. Thus, a cylindrical lithium ion secondary battery can be manufactured.

  The secondary battery having such a configuration is accommodated in the battery pack. The secondary battery is not limited to the above-described configuration, but is a thin lithium ion secondary battery having a polymer electrolyte covered with a laminate film, a flat battery such as a button type or a coin type, or a square battery. A nickel metal hydride (Ni-MH) battery or a nickel-cadmium (Ni-cd) battery can also be used. A single battery may be used, or a plurality of batteries may be connected in series or in parallel depending on the application.

  FIG. 3 shows a circuit configuration of the battery pack 10. FIG. 3 shows an example in which one battery cell is arranged. Power supply pins 21a and 21b and signal pins 23a and 23b are arranged on the USB plug 11, and power supply pins 22a and 22b and signal pins 24a and 24b are arranged on the USB receptacle 12.

  In addition, the state of the secondary battery is monitored during charging, and the charging control circuit 26 including a charge control FET (Field Effect Transistor) that cuts off the charging current when charging is completed; the state of the secondary battery is monitored during discharging; A charge control circuit 26 including a discharge control FET that cuts off a discharge current when the battery becomes a specified voltage or less is disposed, and performs charge / discharge control. In the present invention, the full charge detection method of the battery pack 10 is not particularly limited, and various methods can be used.

  The power supply pins 21a and 21b are connected to the positive electrode side and the negative electrode side of the secondary battery 13 via the charge control circuit 25, and the power supply pins 22a and 22b are connected to the secondary battery 13 via the discharge control circuit 26. It is connected to the positive electrode side and the negative electrode side. The signal pins 23a and 23b are connected to the signal pins 24a and 24b, respectively.

  At this time, as shown in FIG. 4, the signal pins 23a and 23b are connected to the charge control circuit so that the battery capacity information is transmitted to the personal computer at the time of charging, and the liquid crystal display of the personal computer that has received this information. For example, the battery capacity, the remaining charging time, and the like can be displayed on the part.

  FIG. 5 shows a circuit configuration in the case where the battery pack 10 is connected to the desktop or notebook personal computer 30 and the battery pack 10 is charged. The personal computer 30 is equipped with a USB receptacle 31, and charging of the secondary battery 13 is started by inserting and connecting the USB plug 11 of the battery pack. In the case of USB bus power charging, charging with a maximum current of 500 mA is possible.

  When a lithium ion secondary battery is used, full charge detection is performed by constant current constant voltage control. First, immediately after the start of charging, preliminary charging is performed with a small current. Next, rapid charging is performed when a specified battery voltage (for example, 3 V) is reached. The quick charge is performed with a current of about 1C.

  After the battery voltage reaches 4.2V, the battery is further charged at a constant voltage. When the constant voltage charging is performed, the charging current is reduced as the charging progresses, and the charging is controlled to end when the charging current becomes a specified value or less. Further, in order to increase the amount of charge, timer charging may be performed with a small current, for example, for 10 to 30 minutes after the charging current becomes equal to or less than a specified value.

  When using nickel-metal hydride batteries or nickel-cadmium batteries, a method of detecting a voltage drop at the time of full charge peculiar to these batteries is used (detecting a point at which the voltage change becomes negative within a certain time). . The battery voltage rises relatively abruptly at the beginning of charging, and then reaches a period in which the battery voltage hardly changes. After that, the battery voltage rises again and drops slightly after reaching a peak.

  Here, the point at which the initial voltage rise curve becomes gentle is referred to as “initial termination”, and the point at which the voltage rise curve again rises above a certain coefficient is referred to as “late rise”. In addition, the point at which the voltage rise curve becomes gentle after the end rise is called “end end”. As described above, when charging a secondary battery such as a nickel metal hydride battery or a nickel cadmium battery, it is known that the battery voltage changes in a constant pattern. From this change, it is detected that it is the end-of-term rising period or end-of-term termination period, and the end of charging is determined.

  There is also a method of observing a rise in battery temperature, detecting a phenomenon in which the temperature suddenly rises, and determining full charge. Generally, when the secondary battery reaches full charge, the temperature starts to rise rapidly. At this time, with respect to the battery temperature, ΔT / Δt (detects a point at which the temperature rise within a predetermined time changes more than a specified value) is used to detect full charge and determine the end of charge.

  The battery pack 10 charged in this way is detached from the personal computer 30 and is carried and carried to charge an electronic device equipped with a USB terminal outdoors or in a place where it cannot be charged by a personal computer. Can be used as

  FIG. 6 shows a circuit configuration in the case where the battery pack 10 and a USB terminal mounted electronic device 40 such as a portable audio player are connected and the secondary battery 44 of the USB terminal mounted electronic device 40 is charged. The resistance connected in parallel with the secondary battery 44 represents a load included in the USB terminal-equipped electronic device 40. The USB terminal-equipped electronic device 40 is equipped with a USB plug 41, and charging of the USB terminal-equipped electronic device 40 (discharge of the battery pack 10) is started by being connected to the USB receptacle 12 of the battery pack. .

  The battery pack 10 is provided with a discharge control circuit 27 and is controlled so that overdischarge does not occur. In the present invention, the overdischarge detection method of the battery pack 10 is not particularly limited, and various methods can be used.

  For example, the remaining capacity detection by the voltage method measures the terminal voltage of the battery cell and calculates the remaining capacity based on the correlation between the voltage of the secondary battery and the battery capacity (remaining capacity ratio). In this case, when the battery voltage is 4.2 V / cell, the battery is fully charged, and when the battery voltage is 2.4 V / cell, it can be determined that the battery is in an overdischarged state, and measurement is easy.

  In addition, the remaining capacity detection by the current integration method measures the current, integrates the current accumulated every fixed time, measures the voltage and current, and multiplies them to calculate the amount of power, and further, every fixed time. There is a power integration method that integrates the amount of power. In either case, the amount of discharge current or the amount of discharge power can be obtained, and the remaining capacity of the secondary battery can be obtained from the ratio of the battery's usable current amount or amount of power, so that it is not affected by voltage fluctuations. Stable remaining capacity detection becomes possible.

  There is also a method for more accurately detecting the battery capacity by using the current integration method and the voltage method together. For example, the voltage method is used when the current value is smaller than a preset current value, and the current integration method is used when the current value is larger. By measuring the battery capacity by switching each method, the battery capacity calculation accuracy can be improved. .

  In this manner, the secondary battery 44 of the USB terminal-equipped electronic device 40 can be charged.

  Further, as another usage method, it can be used not only as a charging battery but also as an operation power source of the electronic device 40 with a USB terminal.

  For example, as shown in FIG. 7, when the built-in battery of the USB terminal-equipped electronic device 40 runs out, the connection is made in the same way as the charging of the USB terminal-equipped electronic device 40 shown in FIG. 6, and in parallel with the secondary battery 44. It is also possible to drive the USB terminal-equipped electronic device 40 using only the current from the battery pack by passing a current through the connected resistor (the load included in the USB terminal-equipped electronic device 40).

  Further, even when the built-in battery of the USB terminal-equipped electronic device 40 has a remaining capacity, the USB terminal-equipped electronic device 40 can be driven by using the built-in battery and the battery pack together by connecting the battery pack. Yes, it can extend the usage time.

  Further, as shown in FIG. 8, the USB plug 11 of the battery pack 10 is connected to the USB receptacle 31 of the personal computer 30, and the USB plug 41 of the electronic device with a USB terminal is connected to the USB receptacle 12 of the battery pack 10. Is also possible. In this case, the signal pins 33a and 33b of the personal computer 30 are connected to the signal pins 43a and 43b of the USB terminal-equipped electronic device 40 via the battery pack 10, respectively. Therefore, information such as music data can be transferred from the personal computer 30 to the USB terminal-equipped electronic device 40 in parallel with the charging of the battery pack 10. The resistor connected in parallel with the secondary battery 44 represents a load included in the USB terminal-equipped electronic device 40.

  Further, in addition to a battery pack having an appearance as shown in FIG.

  For example, a card type battery pack 50 as shown in FIGS. 9A and 9B may be used. 9A is a top view of the card type battery pack 50, and FIG. 9B is a side view of the card type battery pack 50.

  The card type battery pack 50 is configured to have a length of 52 mm, a width of 84.5 mm, and a thickness of 10 mm, for example. In this case, a thin secondary battery having a length of 52 mm, a width of 84.5 mm, and a thickness of 3 mm is produced and accommodated in the bottom portion of the card type battery pack 50. A circuit including a charge control circuit and a discharge control circuit is accommodated in a circuit accommodating portion 50a located on the upper surface of the card-type battery pack 50, and a USB plug 51 and a USB receptacle are attached to the end of the USB cable led out from the circuit accommodating portion 50a. By configuring so that 52 is connected to each other, the size is equal to that of a generally used cash card except for the thickness, and there is an advantage that it is easy to carry.

  In addition, as shown in FIG. 10, a USB bus terminal 53 is provided on the side surface of the card type battery pack 50 so as to have a function as a USB hub, and another electronic device equipped with a USB terminal is connected to transfer data. Communication is also possible. Here, FIG. 10 is a side view of the card-type battery pack 50.

  In the case of the card-type battery pack as described above, a secondary battery having a polymer electrolyte is used because it cannot be accommodated in the battery pack in a shape like a cylindrical lithium ion secondary battery. It is desirable.

  Furthermore, as shown in FIG. 11, the body part 62 a of the USB receptacle 62 connected to the USB terminal-equipped electronic device is movable. For example, the body part 62 a can be rotated 180 degrees and fixed onto the body part 61 a of the USB plug 61. You may comprise as follows. At this time, a concave portion 63a and a convex portion 63b are provided in each of the trunk portion 61a and the trunk portion 62a so as to be fixed.

  By adopting such a configuration, portability is not impaired even when connected to an electronic device equipped with a USB terminal. Therefore, it is convenient even when connected to an audio player or the like and used for a long time.

  As mentioned above, although embodiment of this invention was described concretely, this invention is not limited to the above-mentioned embodiment, The various deformation | transformation based on the technical idea of this invention is possible.

  For example, the numerical values given in the above embodiment are merely examples, and different numerical values may be used as necessary.

  Also, it may have any appearance as long as it has a USB plug and USB receptacle, and a secondary battery and circuit housed inside, and the shape of the USB connector is A type or B type as required. Various shapes such as a miniA type and a miniB type can be combined.

It is a schematic diagram which shows the usage method in the case of connecting and charging a portable audio player with a built-in memory to a personal computer. It is a schematic diagram which shows the external appearance of the battery pack to which this invention was applied. It is a schematic diagram which shows an example of the circuit structure of the battery pack to which this invention was applied. It is a schematic diagram which shows an example of the circuit structure of the battery pack to which this invention was applied. It is a schematic diagram which shows an example of the circuit structure in the case of charging the battery pack to which this invention was applied. It is a schematic diagram which shows an example of the usage method of the battery pack to which this invention was applied. It is a schematic diagram which shows an example of the usage method of the battery pack to which this invention was applied. It is a schematic diagram which shows an example of the usage method of the battery pack to which this invention was applied. It is a schematic diagram which shows an example of a structure of the battery pack to which this invention was applied. It is a schematic diagram which shows an example of a structure of the battery pack to which this invention was applied. It is a schematic diagram which shows an example of a structure of the battery pack to which this invention was applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Personal computer 2 ... Portable audio player 3 ... AC power adapter 10, 60 ... Battery pack 11, 41, 51, 61 ... USB plug 12, 31, 52, 62 ... USB receptacles 21a, 21b, 22a, 22b, 32a, 32b, 42a, 42b ... power supply pins 23a, 23b, 24a, 24b, 33a, 33b, 43a, 43b ... signal pins 25, 44 ... two Secondary battery 26 ... Charge control circuit 27 ... Discharge control circuit 30 ... Personal computer 40 ... USB terminal-equipped electronic device 50 ... Card type battery pack 50a ... Circuit housing part 53 ... USB bus terminal 61a, 62a ... trunk part 63a ... concave part 63b ... convex part

Claims (8)

A USB plug and a USB receptacle are provided on the exterior body,
A secondary battery connected to the USB plug via a charge control circuit;
A battery pack comprising: the USB receptacle connected to the secondary battery via a discharge control circuit.   The battery pack according to claim 1, wherein the communication pin of the USB plug is connected to the communication pin of the USB receptacle.   The battery pack according to claim 1, wherein the secondary battery is a lithium ion secondary battery.   The battery pack according to claim 1, wherein the USB plug and the USB receptacle are series A plugs each having a rectangular shape.   The battery pack according to claim 1, wherein the exterior body of the battery pack has a rectangular parallelepiped shape.   2. The battery pack according to claim 1, wherein the outer package of the battery pack has a thin shape having a size of a long side and a short side defined in a standard of a cash card or a size smaller than that.   The battery pack according to claim 6, wherein the secondary battery housed in the battery pack is a thin lithium ion secondary battery covered with a laminate film.   The battery pack according to claim 6, wherein at least one USB bus terminal is provided on a side surface of the battery pack.

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