JP4460974B2 - IC tag with non-aqueous electrolyte battery - Google Patents

Description

The present invention relates to an IC tag equipped with a non-aqueous electrolyte battery as a power source.

  Conventionally, a recognition system using a barcode has been widely used as an automatic recognition means for identifying an object without contact. The barcode system is a widely distributed means that has a well-used environment, such as inexpensive and highly reliable media to be recognized, and internationally standardized standards. However, the barcode system has a drawback that the amount of data that can be recorded on the recognized medium is small, and is basically a read-only system, and data cannot be rewritten or corrected.

  Therefore, an automatic data carrier (RF-ID) recognition system combining an ID tag that receives and transmits a radio wave signal using IC technology and a reader / writer thereof is attracting attention. In this system, the IC chip built in the ID tag has an advantage that the memory can be rewritten and larger data can be recorded. In particular, power is supplied from the reader / writer by electromagnetic coupling with the reader / writer, and there is no need to mount a battery on the ID tag, and the ID tag can be used semipermanently.

  However, in the above system, when data is exchanged between the ID tag and the reader / writer, in such a system not equipped with a battery, the communication distance between the ID tag and the reader / writer can be increased. There wasn't. In particular, in a battery-less ID tag that is supplied with power from a reader / writer by electromagnetic coupling with the reader / writer, the internal circuit of the ID tag must be activated if the distance between the two exceeds a certain distance. There was a problem to say.

Thus, for example, as shown in Patent Document 1, an attempt has been made to extend the communication distance by mounting a battery on an ID tag. In Patent Document 1, a PET film (electrode support sheet) in which a positive electrode active material, an electrolyte-impregnated separator, and a negative electrode active material are embedded in holes in an intermediate sheet and a fusion film is bonded to an inner surface is provided on both sides of the intermediate sheet. Discloses a thin electronic device integrated by thermal fusion. Note that a circuit including an antenna and an IC and a carbon electrode are formed on the fusion film. The carbon electrode collects the positive electrode active material and the negative electrode active material and plays a role of connecting adjacent batteries in series.
JP-A-8-77315

  In the thin electronic device described in Patent Document 1, the use of a laminated film of a PET film and a fusion film as an electrode support sheet is not particularly a problem because the battery is a manganese primary battery. When a non-aqueous electrolyte battery such as a lithium battery is used instead of the manganese primary battery for increasing the capacity, capacity deterioration occurs due to intrusion of moisture. In order to prevent the capacity deterioration of the non-aqueous electrolyte battery due to moisture, it is conceivable to use a material containing a metal layer such as an Al foil as the electrode support sheet. There is a risk of inviting.

An object of the present invention is to provide an IC tag equipped with a non-aqueous electrolyte battery of long life despite using a resin container.

A non-aqueous electrolyte battery mounted IC tag according to the present invention includes a resin exterior member having an IC housing portion and an electrode group housing portion,
An IC chip housed in the IC housing portion of the exterior member;
A positive electrode current collector with a positive electrode tab formed on the inner surface of the electrode group housing portion of the exterior member;
A negative electrode current collector with a negative electrode tab formed on the inner surface of the electrode group housing portion so as to face the positive electrode current collector;
A positive electrode layer formed on the positive electrode current collector;
A negative electrode layer formed on the negative electrode current collector;
A separator disposed between the positive electrode layer and the negative electrode layer;
A non-aqueous electrolyte housed in the electrode group housing portion,
The position of the negative electrode tab is shifted from the position of the positive electrode tab, the positive electrode current collector protrudes from the periphery of the positive electrode layer, and the negative electrode current collector protrudes from the periphery of the negative electrode layer. It is what.

According to the present invention, it is possible to provide an IC tag equipped with long-life non-aqueous electrolyte battery comprising a resin container.

  First, an embodiment of a nonaqueous electrolyte battery according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic plan view showing an embodiment of the nonaqueous electrolyte battery of the present invention, FIG. 2 is a schematic cross-sectional view taken along the line II-II of the nonaqueous electrolyte battery of FIG. It is a schematic diagram for demonstrating the manufacturing process of the nonaqueous electrolyte battery of FIG.

  The two resin sheets 1a and 1b are each formed of, for example, a laminate film of a thermoplastic resin film 2 and a resin film 3. The positive electrode current collector 4 with the positive electrode tab 4a is formed on the surface of the thermoplastic resin film 2 of the resin sheet 1a. On the other hand, the negative electrode current collector 5 with the negative electrode tab 5a is formed on the surface of the thermoplastic resin film 2 of the resin sheet 1b. Although the main surface of the negative electrode current collector 5 is opposed to the main surface of the positive electrode current collector 4, the position of the negative electrode tab 5a is shifted from the position of the positive electrode tab 4a to prevent a short circuit. The positive electrode layer 6 is formed on the main surface of the positive electrode current collector 4. The positive electrode current collector 4 protrudes from the four sides of the positive electrode layer 6. On the other hand, the negative electrode layer 7 is formed on the main surface of the negative electrode current collector 5. The negative electrode current collector 5 protrudes from the four sides of the negative electrode layer 7. The separator 8 is disposed between the positive electrode layer 6 and the negative electrode layer 7. The separator 8 has four sides protruding from the positive electrode current collector 4 and the negative electrode current collector 5. A nonaqueous electrolyte (not shown) is held by the separator 8.

  The thermoplastic resin film 2 on the four sides of the resin sheet 1a and the thermoplastic resin film 2 on the four sides of the resin sheet 1b are heat-sealed with the positive electrode tab 4a and the negative electrode tab 5a interposed therebetween. . Thereby, an electrode group will be liquid-tightly accommodated in the container formed with resin-made sheets 1a and 1b.

  According to the nonaqueous electrolyte battery configured as described above, the positive electrode current collector and the negative electrode current collector are formed on the inner surface of the resin container, and the positive electrode current collector projects from the periphery of the positive electrode layer, and Since the negative electrode current collector projects from the periphery of the negative electrode layer, the positive electrode current collector and the negative electrode current collector can function as a moisture blocking layer. As a result, even when a resin container is used, sufficient charge / discharge cycle characteristics can be maintained over a long period of time.

  In addition, by using ceramic separators containing ceramic particles, heat shrinkage during the manufacturing process can be suppressed, and high insulation can be obtained even if it is thin. In addition, it is possible to reduce the internal short-circuit occurrence rate when the thickness is reduced, and it is possible to realize a highly reliable microbattery suitable for a small electronic device such as an IC tag.

  In addition, in FIGS. 1 to 2 described above, an example in which the main surfaces of the current collector (positive electrode current collector and negative electrode current collector) and the electrode layer (positive electrode layer and negative electrode layer) are square has been described. For example, a rectangular shape, a circular shape, or the like can be used. Further, as long as the current collector protrudes from the periphery of the electrode layer, the shape of the electrode layer and the shape of the current collector may be different.

  In the above-described FIGS. 1 to 2, an example in which a sealed container is formed using two resin sheets is described. However, the present invention is not limited to this, and for example, one resin sheet has a thermoplastic resin surface on the inside. It is also possible to construct a sealed container by folding it in half and sealing the three sides by heat sealing.

  Hereinafter, the positive electrode layer, the positive electrode current collector, the negative electrode layer, the negative electrode current collector, the separator, the nonaqueous electrolyte, and the resin sheet will be described.

1) Positive electrode layer The positive electrode layer contains a positive electrode active material and a binder.

Examples of the positive electrode active material include various oxides and sulfides. For example, ₍₂ MnO) manganese dioxide, iron oxide, copper oxide, nickel oxide, lithium-manganese composite oxide (e.g., Li _x MnO _2, such as _{Li x Mn 2 O 4, LiMnO} 2 , such as LiMn ₂ O _4), lithium nickel composite oxide (e.g., _{Li x NiO 2), (Li} x CoO 2 , such as for example, LiCoO ₂₎ lithium-cobalt composite oxide, LiNi _1-y Co such as lithium nickel cobalt composite oxide (e.g., LiNi _0.8 Co _0.2 O _{2 y} O _2), lithium manganese cobalt composite oxides (e.g. _{LiMn y Co 1-y O 2} ), spinel type lithium-manganese-nickel composite oxide _{(Li x Mn 2-y Ni} y O 4), lithium phosphate having an olivine structure oxide _{(Li x FePO 4, Li x} Fe 1-y Mn y PO 4, Li , etc. _x CoPO _4), iron sulfate (Fe ₂ (SO _{4) 3} ) And vanadium oxide (for example, V ₂ O ₅ ). In addition, conductive polymer materials such as polyaniline and polypyrrole, disulfide-based polymer materials, organic materials such as sulfur (S) and carbon fluoride, and inorganic materials are also included. More preferable positive electrode for secondary battery is lithium manganese composite oxide, lithium nickel composite oxide, lithium cobalt composite oxide, lithium nickel cobalt composite oxide, spinel type lithium manganese nickel composite oxide, lithium manganese having high battery voltage. Examples include cobalt composite oxide and lithium iron phosphate. In addition, it is preferable that x and y are the range of 0-1.

  As the binder, for example, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), ethylene-propylene-diene copolymer (EPDM), styrene-butadiene rubber (SBR), or the like can be used.

  The positive electrode layer may contain a conductive agent. Examples of the conductive agent include acetylene black, carbon black, and graphite.

  The blending ratio of the positive electrode active material, the conductive agent and the binder is preferably in the range of 80 to 95% by weight of the positive electrode active material, 3 to 20% by weight of the conductive agent, and 2 to 7% by weight of the binder.

  The thickness of the positive electrode layer is preferably in the range of 10 to 150 μm. Here, the thickness of the positive electrode layer means the distance between the surface of the positive electrode layer facing the separator and the surface of the positive electrode layer in contact with the current collector. By setting the thickness of the positive electrode layer within the range of 10 to 150 μm, the large current discharge characteristics and the cycle life can be improved. The thickness of the positive electrode layer is more preferably in the range of 30 to 100 μm. By setting it in this range, the large current discharge characteristics and the cycle life can be greatly improved.

  The positive electrode layer may contain an adhesive polymer. The polymer having adhesiveness is desirably one that can maintain high adhesiveness while holding the nonaqueous electrolyte. Furthermore, it is more preferable that such a polymer has high lithium ion conductivity. Specific examples include polyacrylonitrile (PAN), polyacrylate (PMMA), polyvinylidene fluoride (PVdF), polyvinyl chloride (PVC), and polyethylene oxide (PEO). As the polymer having adhesiveness, one or more selected from the above-mentioned types can be used. In particular, polyvinylidene fluoride is preferable. Polyvinylidene fluoride can retain a non-aqueous electrolyte, and if it contains a non-aqueous electrolyte, it partially gels, so that the ionic conductivity can be further improved.

  In addition, you may contain the polymer | macromolecule which has adhesiveness in the negative electrode layer and separator which are mentioned later. The total amount of the polymer having adhesiveness contained in the battery is preferably 0.1 to 6 mg per 100 mAh of battery capacity. A more preferable range of the total amount of the polymer having adhesiveness is 0.2 to 1 mg per 100 mAh of battery capacity.

2) Positive electrode current collector The positive electrode current collector can be formed of, for example, aluminum, an aluminum alloy, or titanium. The current collector is obtained, for example, by forming a film on a resin sheet. The film forming means is not particularly limited. For example, metal powder coating (for example, screen printing), vapor deposition, sputtering, or the like can be employed.

  The thickness of the current collector is preferably in the range of 5 to 20 μm. This is because within this range, the balance between the positive electrode strength and the weight reduction can be achieved.

3) Negative electrode layer The negative electrode active material is not particularly limited as long as it is a material that absorbs and releases lithium. For example, carbonaceous materials, alloys, oxides, nitrides, sulfides, which are known active materials, Carbides and the like can be listed. In addition, from the viewpoint of reliability during overdischarge, a negative electrode active material in which the negative electrode operating potential is nobler than 1 V with respect to the lithium metal potential is preferable, and examples include lithium titanate and iron sulfide.

Examples of carbonaceous materials include graphite materials such as graphite, coke, carbon fiber, and spherical carbon, or carbonaceous materials, thermosetting resins, isotropic pitches, mesophase pitches, mesophase pitch-based carbon fibers, mesophase microspheres, etc. A mesophase pitch-based carbon fiber is preferable because the capacity and charge / discharge cycle characteristics are increased), and a graphite material or a carbonaceous material obtained by heat treatment at 500 to 3000 ° C. can be used. Among them, it is preferable to use a graphitic material having graphite crystals obtained by setting the temperature of the heat treatment to 2000 ° C. or more and having a (002) plane spacing d ₀₀₂ of 0.34 nm or less. A nonaqueous electrolyte secondary battery including a negative electrode containing such a graphite material as a carbonaceous material can greatly improve battery capacity and large current discharge characteristics. Plane spacing d ₀₀₂ is more preferably at most 0.336 nm.

  Examples of the alloy include lithium alloys such as a lithium aluminum alloy, a lithium tin alloy, a lithium lead alloy, and a lithium silicon alloy.

  Examples of the oxide include metal oxides such as tin oxide, silicon oxide, lithium titanium oxide, niobium oxide, and tungsten oxide.

  Examples of the nitride include metal nitrides such as lithium cobalt nitride, lithium iron nitride, and lithium manganese nitride.

  Examples of the sulfide include metal sulfides such as tin sulfide and titanium sulfide.

  The negative electrode active material preferably has an average particle size of 0.1 to 10 μm. If it is smaller than 0.1 μm, it is necessary to increase the amount of the conductive agent in order to ensure the current collecting performance, and the effective negative electrode capacity may be reduced. In addition, workability in manufacturing is greatly reduced. On the other hand, if it exceeds 10 μm, the current collecting performance may be lowered.

The negative electrode active material preferably has a specific surface area of 5 m ² / g or more and 100 m ² / g or less. If the specific surface area is less than 5 m ² / g, the current collecting performance may be lowered. On the other hand, if the specific surface area exceeds 100 m ² / g, it is necessary to increase the amount of the conductive agent, which may reduce the effective negative electrode capacity. In addition, workability in manufacturing is greatly reduced.

  The negative electrode layer can contain a binder. As the binder, for example, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), ethylene-propylene-diene copolymer (EPDM), styrene-butadiene rubber (SBR), carboxymethylcellulose (CMC), or the like is used. be able to.

  The negative electrode layer can contain a conductive agent. Examples of the conductive agent include acetylene black, carbon black, and graphite.

  The mixing ratio of the negative electrode active material, the conductive agent and the binder is preferably in the range of 70 to 96% by weight of the negative electrode active material, 2 to 28% by weight of the conductive agent, and 2 to 28% by weight of the binder. If the amount of the conductive agent is less than 2% by weight, there is a possibility that the current collecting property is lacking and the large current characteristic is deteriorated. Further, if the amount of the binder is less than 2% by weight, the binding performance between the mixture layer and the current collector is lacking, and the cycle performance may be deteriorated. On the other hand, from the viewpoint of increasing the capacity, the amount of the conductive agent and the binder is preferably 28% by weight or less.

When a carbonaceous material is used as the negative electrode active material, the blending ratio of the carbonaceous material and the binder is preferably in the range of 90 to 98% by weight of the carbonaceous material and 2 to 10% by weight of the binder. In particular, the carbonaceous material is preferably in the range of 10 to 70 g / cm ^{2 on} one side in a state where the negative electrode is produced. The packing density is preferably in the range of 1.2 to 1.5 g / cm ³ .

  The thickness of the negative electrode layer is preferably in the range of 10 to 150 μm. Here, the thickness of the negative electrode layer means the distance between the surface of the negative electrode layer facing the separator and the surface of the negative electrode layer in contact with the current collector. By setting the thickness of the negative electrode layer within the range of 10 to 150 μm, the large current discharge characteristics and the cycle life can be improved. The thickness of the negative electrode layer is more preferably in the range of 30 to 100 μm. By setting it in this range, the large current discharge characteristics and the cycle life can be greatly improved.

4) Negative electrode current collector The negative electrode current collector can be formed of, for example, copper, copper alloy, aluminum, aluminum alloy, or nickel. From the viewpoint of reliability during overdischarge, the negative electrode current collector is preferably aluminum or an aluminum alloy. The current collector is obtained, for example, by forming a film on a resin sheet. The film forming means is not particularly limited. For example, metal powder coating (for example, screen printing), vapor deposition, sputtering, or the like can be employed.

  The thickness of the current collector is preferably in the range of 5 to 20 μm. This is because the negative electrode strength and weight reduction can be balanced within this range.

5) Separator A porous separator is used as the separator.

Examples of the porous separator include insulating films such as a porous film containing polyethylene, polypropylene, cellulose, or polyvinylidene fluoride (PVdF), a nonwoven fabric made of synthetic resin, and ceramic fine particles (eg, SiO ₂ , Al ₂ O _3, etc.). Examples thereof include a porous thin film containing particles. A porous thin film containing ceramic particles can be obtained, for example, by forming ceramic particles with a binder.

  The ceramic particle content in the separator is desirably 70% by weight or more and 96% by weight or less. This is due to the reason explained below. If the content of the ceramic particles is less than 70% by weight, there is a possibility that the effect of reducing the internal short-circuit occurrence rate when the separator is thinned and has a small area may not be obtained. On the other hand, when the content of the ceramic particles exceeds 96% by weight, the lithium ion permeability may be lowered or the nonaqueous electrolyte holding amount may be lowered. A more preferable range of the content is 80% by weight or more and 95% by weight or less.

  The thickness of the separator is preferably in the range of 5 to 30 μm. This is due to the following reason. As the thickness of the separator increases, the battery resistance after the hole is closed increases, so that the battery function can be quickly stopped. However, if the thickness exceeds 30 μm, the weight energy density and volume energy density of the secondary battery may be lowered. The upper limit value of the thickness is more preferably 25 μm, and the lower limit value is more preferably 10 μm.

The separator preferably has an air permeability of 600 seconds / 100 cm ³ or less. The air permeability means time (seconds) required for 100 cm ³ of air to pass through the separator. If the air permeability exceeds 600 seconds / 100 cm ³ , it may be difficult to obtain high lithium ion mobility in the separator. Further, the lower limit value of the air permeability is preferably 100 seconds / 100 cm ³ . When the air permeability is less than 100 seconds / 100 cm ³ , there is a possibility that sufficient separator strength cannot be obtained and the hole closing start temperature may be increased. The upper limit value of the air permeability is more preferably 500 seconds / 100 cm ^3, and a more preferable upper limit value is 400 seconds / 100 cm ³ . The lower limit is more preferably 150 seconds / 100 cm ³ .

  The separator preferably has a porosity in the range of 30 to 60%. This is due to the following reason. If the porosity is less than 30%, it may be difficult to obtain high electrolyte retention in the separator. On the other hand, if the porosity exceeds 60%, sufficient separator strength may not be obtained. A more preferable range of the porosity is 35 to 50%.

6) Non-aqueous electrolyte As the non-aqueous electrolyte, a liquid one can be used. Examples of the liquid non-aqueous electrolyte include those in which an electrolyte is dissolved in an organic solvent and those containing a room temperature molten salt containing lithium ions.

(6-1) Non-aqueous electrolyte solution in which electrolyte is dissolved in organic solvent As the organic solvent, a known organic solvent can be used as a solvent for the non-aqueous electrolyte battery. EC), cyclic carbonates such as propylene carbonate (PC) and vinylene carbonate (VC), chain carbonates such as dimethyl carbonate (DMC), methyl ethyl carbonate (MEC) and diethyl carbonate (DEC), tetrahydrofuran (THF), 2-methyl Examples include cyclic ethers such as tetrahydrofuran (2MeTHF), chain ethers such as dimethoxyethane (DME), γ-butyrolactone (BL), acetonitrile (AN), sulfolane (SL), and the like. These organic solvents can be used alone or in the form of a mixture of two or more.

  Among them, mixing of a first solvent composed of propylene carbonate (PC) and / or ethylene carbonate (EC) and one or more non-aqueous solvents (hereinafter referred to as second solvents) having a lower viscosity than PC and EC. It is preferable to use a non-aqueous solvent mainly composed of a solvent. The blending amount of the first solvent in the mixed solvent is preferably 10 to 80% by volume ratio. A more preferable amount of the first solvent is 20 to 75% by volume.

  Examples of the second solvent include chain carbonate, ethyl propionate, methyl propionate, γ-butyrolactone (γ-BL), acetonitrile (AN), ethyl acetate (EA), toluene, xylene, and methyl acetate (MA). Etc. These second solvents can be used alone or in the form of a mixture of two or more. Among these, chain carbonate is preferable. The second solvent preferably has a donor number of 16.5 or less.

  The viscosity of the second solvent is preferably 28 mp or less at 25 ° C.

Examples of the electrolyte include lithium perchlorate (LiClO ₄ ), lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), lithium hexafluoroarsenide (LiAsF ₆ ), and trifluorometa. Examples thereof include lithium salts such as lithium sulfonate (LiCF ₃ SO ₃ ) and lithium bistrifluoromethylsulfonylimide [LiN (CF ₃ SO ₂ ) ₂ ]. Of these, LiPF ₆ and LiBF ₄ are preferably used.

  The amount of electrolyte dissolved in the organic solvent is desirably 0.5 to 2 mol / L.

  A particularly preferred liquid non-aqueous electrolyte is one in which an electrolyte (for example, lithium salt) is dissolved in a mixed non-aqueous solvent containing γ-butyrolactone (BL), and the BL composition ratio is 40% by volume or more of the entire mixed non-aqueous solvent. 95% by volume or less.

  In the mixed non-aqueous solvent, it is preferable that the BL composition ratio is maximized. If the ratio is less than 40% by volume, gas tends to be generated at high temperatures. In addition, when the mixed non-aqueous solvent contains BL and cyclic carbonate, the ratio of the cyclic carbonate becomes relatively high, and thus the solvent viscosity may be remarkably increased. When the solvent viscosity increases, the conductivity and permeability of the liquid non-aqueous electrolyte decrease, so that the charge / discharge cycle characteristics, the large current discharge characteristics, and the discharge characteristics under a low temperature environment around −20 ° C. decrease. On the other hand, if the ratio exceeds 95% by volume, the reaction between the negative electrode and BL tends to occur, and the charge / discharge cycle characteristics may deteriorate. That is, when the negative electrode (for example, containing a carbonaceous material that occludes and releases lithium ions) reacts with BL to cause reductive decomposition of the liquid nonaqueous electrolyte, a coating that inhibits the charge / discharge reaction is formed on the surface of the negative electrode. The As a result, current concentration tends to occur in the negative electrode, so that lithium metal is deposited on the negative electrode surface, or the impedance of the negative electrode interface increases, the charge / discharge efficiency of the negative electrode decreases, and charge / discharge cycle characteristics are deteriorated. A more preferable range is 60% by volume or more and 90% by volume or less. By setting it within this range, it is possible to further increase the effect of suppressing gas generation during high-temperature storage, and to further improve the discharge capacity in a low temperature environment around −20 ° C. A more preferable range is 75% by volume or more and 90% by volume or less.

  As a solvent mixed with BL, a cyclic carbonate is desirable in terms of increasing the charge / discharge efficiency of the negative electrode. As the cyclic carbonate, propylene carbonate (PC), ethylene carbonate (EC), vinylene carbonate (VC), trifluoropropylene carbonate (TFPC) and the like are desirable. In particular, when EC is used as a solvent mixed with BL, charge / discharge cycle characteristics and large current discharge characteristics can be significantly improved.

  Moreover, as another solvent mixed with BL, a third solvent consisting of at least one selected from the group consisting of PC, VC, TFPC, diethyl carbonate (DEC), methyl ethyl carbonate (MEC), and an aromatic compound, and EC The mixed solvent is desirable in terms of enhancing the charge / discharge cycle characteristics.

  Further, from the viewpoint of lowering the solvent viscosity, a low viscosity solvent may be contained in an amount of 20% by volume or less. Examples of the low viscosity solvent include chain carbonates, chain ethers, cyclic ethers and the like.

  More preferable composition of the organic solvent is BL and EC, BL and PC, BL and EC and DEC, BL and EC and MEC, BL and EC and MEC and VC, BL and EC and VC, BL and PC and VC, or BL EC, PC, and VC. At this time, the volume ratio of EC is preferably 5 to 40% by volume. This is due to the following reason. If the EC ratio is less than 5% by volume, it may be difficult to cover the negative electrode surface densely with a protective film, so that the reaction between the negative electrode and BL occurs, and the charge / discharge cycle characteristics can be sufficiently improved. It can be difficult. On the other hand, if the EC ratio exceeds 40% by volume, the viscosity of the liquid non-aqueous electrolyte is increased and the ionic conductivity may be lowered. Therefore, sufficient charge / discharge cycle characteristics, large current discharge characteristics, and low temperature discharge characteristics are sufficiently obtained. It can be difficult to improve. A more preferable range of the EC ratio is 10 to 35% by volume. Moreover, it is preferable to make the ratio of the solvent which consists of at least 1 type chosen from DEC, MEC, and VC in the range of 0.5-10 volume%.

Examples of the electrolyte include the same ones as described above. Among them, it is preferable to use LiPF ₆ or LiBF ₄ .

  The amount of electrolyte dissolved in the organic solvent is desirably 0.5 to 2 mol / L.

  To the liquid non-aqueous electrolyte containing γ-BL, a surfactant such as trioctyl phosphate may be added in the range of 0.1 to 1% in order to improve the paintability with the separator.

  The amount of the liquid non-aqueous electrolyte is preferably 0.2 to 0.6 g per 100 mAh of battery unit capacity. This is due to the following reason. If the liquid nonaqueous electrolytic mass is less than 0.2 g / 100 mAh, the ionic conductivity of the positive electrode and the negative electrode may not be sufficiently maintained. On the other hand, if the liquid non-aqueous electrolytic mass exceeds 0.6 g / 100 mAh, the amount of electrolyte increases, and sealing by heat sealing may be difficult. A more preferable range of the liquid nonaqueous electrolytic mass is 0.4 to 0.55 g / 100 mAh.

(6-2)
Moreover, a room temperature molten salt containing lithium ions can be used as the non-aqueous electrolyte.

  The room temperature molten salt refers to a salt that is at least partially in a liquid state at room temperature, and the room temperature refers to a temperature range in which a power supply is assumed to normally operate. The temperature range in which the power supply is assumed to normally operate has an upper limit of about 120 ° C. and in some cases about 60 ° C., and a lower limit of about −40 ° C. and in some cases about −20 ° C.

As the lithium salt, a lithium salt having a wide potential window, which is generally used for lithium secondary batteries, is used. For example, as the lithium salt, a lithium salt having a wide potential window, which is generally used for lithium secondary batteries, is used. For example, LiBF ₄ , LiPF ₆ , LiClO ₄ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ), LiN (CF ₃ SC (C ₂ F ₅ SO ₂ ) _3, etc. However, these are not limited, and these may be used alone or in combination of two or more.

  The content of the lithium salt in the nonaqueous electrolyte is desirably 0.1 to 3 mol / L. This is due to the reason explained below. If the content of the lithium salt is less than 0.1 mol / L, the ionic conductivity of the non-aqueous electrolyte is lowered and there is a possibility that excellent large current / low temperature discharge characteristics cannot be obtained. On the other hand, when the content of the lithium salt exceeds 3 mol / L, the melting point of the non-aqueous electrolyte is increased and it may be difficult to maintain a liquid state at room temperature. A more preferable range of the lithium salt content is 1 to 2 mol / L.

As the room temperature molten salt, for example, a salt having a quaternary ammonium organic cation having a skeleton represented by the formula (A) of Chemical Formula 1 or an imidazolium cation having a skeleton represented by the Formula (B) of Chemical Formula 2 Is.

However, in the formula (B), R1 and R2 are each C _n H _{2n + 1} (n = 1 to 6), and may be the same or different from each other, and R3 is H or C _n H _{2n +1} (n = 1 to 6).

  Examples of the quaternary ammonium organic cation having a skeleton represented by the formula (A) include imidazolium ions such as dialkylimidazolium and trialkylimidazolium, tetraalkylammonium ions, alkylpyridinium ions, pyrazolium ions, pyrrolidinium ions, pipettes. Examples include ridinium ions. In particular, an imidazolium cation having a skeleton represented by the formula (B) is preferable.

  Examples of the tetraalkylammonium ion include, but are not limited to, trimethylethylammonium ion, trimethylethylammonium ion, trimethylpropylammonium ion, trimethylhexylammonium ion, and tetrapentylammonium ion.

  Examples of the alkylpyridium ion include N-methylpyridinium ion, N-ethylpyridinium ion, N-propylpyridinium ion, N-butylpyridinium ion, 1-ethyl-2-methylpyridinium ion, 1-butyl-4-methylpyridinium ion Ions, 1-butyl-2,4 dimethylpyridinium ions and the like, but are not limited thereto.

  In addition, the normal temperature molten salt which has these cations may be used independently, or may be used in mixture of 2 or more types.

  The imidazolium cation having a skeleton represented by the formula (B) will be described. Examples of the dialkylimidazolium ion include 1,3-dimethylimidazolium ion, 1-ethyl-3-methylimidazolium ion, 1-methyl-3-ethylimidazolium ion, 1-methyl-3-butylimidazolium ion, 1 -Butyl-3-methylimidazolium ion and the like. On the other hand, as the trialkylimidazolium ion, 1,2,3-trimethylimidazolium ion, 1,2-dimethyl-3-ethylimidazolium ion, 1, Examples thereof include, but are not limited to, 2-dimethyl-3-propylimidazolium ion and 1-butyl-2,3-dimethylimidazolium ion.

  In addition, the normal temperature molten salt which has these cations may be used independently, or may mix and use 2 or more types.

7) Resin sheet The resin sheet includes the laminate film of the thermoplastic resin film and the resin film described above, but is not limited to this, for example, even if the thermoplastic resin film is used alone, or the inner surface Alternatively, a printed circuit board in which a thermoplastic resin is disposed may be used.

  Examples of the thermoplastic resin include polyolefin. Examples of the polyolefin include polyethylene (PE) and polypropylene (PP). As the thermoplastic resin, one kind selected from the kinds described above, or two or more kinds such as a mixture of polyethylene and polypropylene can be used. The melting point of polyolefin varies depending on the crystallinity. Therefore, it is desirable to use a polyolefin having a target melting point as the thermoplastic resin.

  Examples of the resin constituting the resin film include nylon and polyethylene terephthalate (PET). The kind of resin film to be used is not limited to one kind, and can be two or more kinds.

  The thickness of the resin sheet is preferably 0.5 mm or less. If it exceeds 0.5 mm, the capacity per weight of the battery may be reduced. The thickness of the resin sheet is preferably 0.3 mm or less, more preferably 0.25 mm or less, and most preferably 0.15 mm or less. On the other hand, if the thickness is less than 0.05 mm, deformation or breakage tends to occur. For this reason, the lower limit value of the thickness is preferably 0.05 mm. A more preferred lower limit is 0.08 mm, and a most preferred range is 0.1 mm.

  An example of the method for producing the nonaqueous electrolyte battery of the present invention will be described with reference to FIG.

  For example, among resin sheets 1a and 1b made of a laminate film of thermoplastic resin film 2 and resin film 3, positive electrode current collectors 4 with positive electrode tabs 4a are arranged at equal intervals on the surface of thermoplastic resin film 2 of resin sheet 1a. For example, it is formed by screen printing, vapor deposition, sputtering or the like. A positive electrode layer 6 is formed by applying a slurry containing a positive electrode active material and a binder onto the positive electrode current collector 4 except for the ends of the four sides and drying. Subsequently, a separator 8 is formed by applying a paste containing ceramic particles and a binder onto the positive electrode layer 6.

  On the other hand, the negative electrode current collector 5 with the negative electrode tab 5a is formed on the surface of the thermoplastic resin film 2 of the resin sheet 1b at regular intervals, for example, by screen printing, vapor deposition, sputtering, or the like. The slurry containing the negative electrode active material and the binder is applied on the negative electrode current collector 5 except for the ends of the four sides, and dried to form the negative electrode layer 7.

  After the separator 8 of the resin sheet 1a is dried, an appropriate amount of electrolyte (a certain amount that does not impair sealing by heat sealing) is dropped on the separator 8 and the electrode group is formed by overlapping the negative electrode layer 7 of the resin sheet 1b. After the formation, the resin sheets 1a and 1b around the electrode group are sealed by thermal fusion through the positive and negative electrode tabs 4a and 5a therebetween. Next, the cell is divided into individual cells by dicing to obtain a nonaqueous electrolyte battery. Note that the heat sealing temperature is desirably 80 ° C. or higher and 120 ° C. or lower.

  Hereinafter, an embodiment of an IC tag provided with a nonaqueous electrolyte battery according to the present invention will be described with reference to FIGS.

  4 is a perspective view schematically showing an embodiment of a battery-mounted IC tag according to the present invention, FIG. 5 is a cross-sectional view of the IC tag of FIG. 4 taken along line VV, and FIG. 4 is a cross-sectional view taken along line VI-VI, FIG. 7 is a cross-sectional view taken along line VII-VII, and FIG. 8 is a cross-sectional view taken along line VII-VII. It is sectional drawing cut | disconnected along the VIII-VIII line.

  As shown in FIG. 4, the IC tag 9 includes an exterior member 10 having an electrode group housing portion and an IC housing portion, an IC (integrated circuit) chip 11 housed in the IC housing portion of the exterior member 10, and the exterior member 10. The electrode group 12 accommodated in this electrode group accommodating part and the antenna 13 sealed in the exterior member 10 are provided.

  The exterior member 10 is formed by heat-sealing from two resin sheets 14a and 14b. For each resin sheet 14a, 14b, for example, a laminate film of a thermoplastic resin film 15 and a resin film 16 can be used. The IC chip 11, the electrode group 12 and the antenna 13 are sandwiched between the two resin sheets 14a and 14b, and the thermoplastic resin films 15 around these components are bonded together by thermal fusion, thereby the IC chip 11, The electrode group 12 and the antenna 13 are sealed between the resin sheets 14a and 14b. Therefore, the exterior member 10 serves not only as a package for the IC chip 11 and the antenna 13 but also as a container for housing the electrode group of the nonaqueous electrolyte battery.

  In the electrode group housing portion, the positive electrode current collector 4 with the positive electrode tab 4 a is formed on the inner surface (the surface of the thermoplastic resin film 15) of the exterior member 10. On the other hand, the negative electrode current collector 5 with the negative electrode tab 5 a is formed on the inner surface (thermoplastic resin film 15 surface) on the opposite side of the exterior member 10. While the main surface of the negative electrode current collector 5 faces the main surface of the positive electrode current collector 4, the position of the negative electrode tab 5a is shifted from the position of the positive electrode tab 4a to prevent a short circuit. The positive electrode layer 6 is formed on the main surface of the positive electrode current collector 4. The positive electrode current collector 4 protrudes from the four sides of the positive electrode layer 6. On the other hand, the negative electrode layer 7 is formed on the main surface of the negative electrode current collector 5. The negative electrode current collector 5 protrudes from the four sides of the negative electrode layer 7. The separator 8 is disposed between the positive electrode layer 6 and the negative electrode layer 7. The separator 8 has four sides protruding from the positive electrode current collector 4 and the negative electrode current collector 5. A nonaqueous electrolyte (not shown) is held by the separator 8.

  As shown in FIG. 6, the IC chip 11 is accommodated in the IC accommodating portion of the exterior member 10. The IC chip 11 and the positive and negative electrode tabs 4a and 5a of the electrode group 12 in the electrode group housing portion are electrically connected by a wiring 17 disposed between the resin sheets 14a and 14b. As a result, current can be supplied from the IC chip 11 to the nonaqueous electrolyte battery, and power can be supplied from the nonaqueous electrolyte battery to the IC chip 11.

  The antenna 13 is disposed between the resin sheets 14a and 14b. The antenna 13 is connected to the IC chip 11 by wiring 18. As a result, communication between the IC chip 11 and the antenna 13 becomes possible.

  The operation of the IC tag 9 having the configuration described above will be described.

  When the IC tag 9 enters an RF (Radio Frequency) field generated by a reader / writer (not shown), the reader / writer supplies an RF signal including data and electromagnetic waves to the IC tag 9. The IC tag 9 receives an RF signal at the antenna 13 and transmits it to the IC chip 11 via the wiring 18. The IC chip 11 extracts the data component from the RF signal, and transmits its own ID (identification code) and data from the antenna 13 to the reader / writer. The IC tag 9 converts an electromagnetic wave into a current by electromagnetic induction in a coil (not shown) provided in the antenna 13 and supplies the current to the nonaqueous electrolyte battery via the wirings 17 and 18. The non-aqueous electrolyte battery is charged and electric power is supplied to the IC chip 11 via the wiring 17.

  In the nonaqueous electrolyte battery, the positive electrode current collector 4 and the negative electrode current collector 5 are formed on the inner surface of the resin exterior member 10, the positive electrode current collector 4 protrudes from the periphery of the positive electrode layer 6, and the negative electrode layer 7. Since the negative electrode current collector 5 protrudes from the peripheral edge, the positive electrode current collector 4 and the negative electrode current collector 5 can function as a moisture blocking layer. As a result, even when the resin exterior member 10 is used, sufficient charge / discharge cycle characteristics can be maintained over a long period of time, so that the lifetime of the IC tag can be improved.

  Therefore, since the charge / discharge cycle life of the battery can be improved without using metal for the exterior member 10, it is possible to provide an IC tag having a long life with less problems such as antenna interference.

  In addition, by enclosing the antenna and IC chip in an exterior member that also serves as a battery container, the IC tag can be made smaller and lighter, and the process of antenna formation and IC chip mounting is incorporated into a series of battery manufacturing processes. Therefore, productivity can be improved and costs can be reduced.

  Furthermore, since the negative electrode layer contains lithium titanate, unlike the case of the carbonaceous material negative electrode, such a negative electrode does not require the formation of a protective coating called SEI (Solid electrolyte interphase film). Therefore, the battery can be shipped without using the IC tag and is more suitable as a battery for IC tag power supply. Further, by forming the current collector from aluminum or an aluminum alloy, the weight reduction of the battery-mounted IC tag can be promoted.

  Another embodiment of the battery-mounted IC tag is shown in FIGS. 9 to 12, members similar to those in FIGS. 4 to 8 described above are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIGS. 9 and 10, the antenna 13 is disposed so as to surround the electrode group 12 and is electrically connected to the positive and negative electrode tabs 4 a and 5 a of the electrode group 12 through the wiring 19. Yes. The IC chip 11 is disposed in a region surrounded by the antenna 13, connected to the positive and negative electrode tabs 4 a and 5 a of the electrode group 12 through the wiring 20, and connected to the antenna 13 through the wiring 21. Yes.

  On the other hand, in FIGS. 11 to 12, the IC chip 11 is arranged on the exterior member 10 of the electrode group housing portion. The IC chip 11 is electrically connected to the positive and negative electrode tabs 4 a and 5 a of the electrode group 12 through the wiring 22. The antenna 13 is disposed so as to surround the electrode group 12. The antenna 13 is connected to the positive and negative electrode tabs 4 a and 5 a of the electrode group 12 through a wiring 23 and is connected to the IC chip 11 through a wiring 24. The IC chip 11 and the wiring 22 are covered with a resin cover 25.

  11 to 12, the antenna 13 is disposed on the surface of the exterior member 10. However, the antenna 13 may be disposed between the resin sheets 14 a and 14 b of the exterior member 10.

[Example]
Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples as long as the gist of the invention is not exceeded.

( Reference Example 1)
Laminate films in which a PET layer having a thickness of 100 μm and a PE layer having a thickness of 50 μm were laminated were prepared as resin sheets 1a and 1b. A positive electrode current collector 4 made of an Al foil having a thickness of 15 μm was formed by screen printing on a PE layer serving as a heat-sealing layer of the resin sheet 1a. The area of the main surface of the positive electrode current collector 4 was 4 mm × 4 mm, 16 mm ² .

As a positive electrode active material, 90% by weight of lithium cobalt oxide (LiCoO ₂ ) powder, 3% by weight of acetylene black, 3% by weight of graphite and 4% by weight of polyvinylidene fluoride (PVdF) are added to N-methylpyrrolidone (NMP) and mixed. A slurry was prepared. This slurry was applied on the positive electrode current collector 4 except for the ends of the four sides, and dried to form a positive electrode layer 6 having a positive electrode area of 3 mm × 3 mm and 9 mm ² .

Subsequently, a separator 8 was formed so as to cover the positive electrode layer 6 with silica (SiO ₂ ) powder having an average diameter of 0.1 μm using PVdF as a binder. The film thickness was 25 μm. Moreover, content of the silica in the separator 8 was 85 weight%.

On the other hand, the negative electrode current collector 5 made of an Al foil having a thickness of 15 μm was formed by screen printing on the PE layer serving as the heat-sealing layer of the resin sheet 1b. The area of the main surface of the negative electrode current collector 5 was 4 mm × 4 mm, 16 mm ² .

Lithium titanate Li ₄ Ti ₅ O ₁₂ , acetylene black having an average particle diameter of 1 μm and a specific surface area of 8 m ² / g as conductive material, and polyvinylidene fluoride (PVdF) in a weight ratio of 90: 5: 5 The slurry was prepared by adding to the N-methylpyrrolidone (NMP) solution and mixing. The slurry was applied on the negative electrode current collector 5 except for the ends of the four sides, and dried to form a negative electrode layer 7 having a negative electrode area of 3 mm × 3 mm and 9 mm ² .

A liquid non-aqueous electrolyte is prepared by dissolving 1.5 mol / L of lithium tetrafluoroborate (LiBF ₄ ) as an electrolyte in a mixed solvent (volume ratio 25:75) of ethylene carbonate (EC) and γ-butyrolactone (BL). (Nonaqueous electrolyte) was prepared.

  After the separator 8 of the resin sheet 1a is dried, an electrolytic solution is dropped thereon, and the electrode group 12 is formed by overlapping the negative electrode layer 7 of the resin sheet 1b, and then the resin sheet 1a around the electrode group 12 is formed. , 1b are sealed by thermal fusion with the positive and negative electrode tabs 4a, 5a interposed therebetween, to obtain the nonaqueous electrolyte secondary battery having the structure shown in FIG.

(Comparative Example 1)
A nonaqueous electrolyte secondary battery was obtained in the same manner as described in Reference Example 1 except that the area of the main surface of the current collector was reduced to 4 mm ^{2 of} 2 mm × 2 mm for both the positive electrode and the negative electrode.

(Comparative Example 2)
As shown in FIG. 13, a nonaqueous electrolyte secondary battery was obtained in the same manner as described in Reference Example 1 except that the area of the main surface of the current collector was made equal to the electrode area for both the positive electrode and the negative electrode. .

For the secondary batteries of Reference Example 1 and Comparative Examples 1 and 2, a charge / discharge cycle of charging at 0.2 mA (1 C) for 1 second and discharging at 0.2 mA (1 C) was repeated, and the discharge capacity was 80% of the initial capacity. The number of cycles until the value decreases to the value is measured, and the results are shown in Table 1 below.

As is clear from Table 1, the secondary battery of Reference Example 1 in which the positive electrode current collector protrudes from the peripheral edge of the positive electrode layer and the negative electrode current collector protrudes from the peripheral edge of the negative electrode layer has a charge / discharge cycle life of 6000. It was long.

On the other hand, in the secondary battery of Comparative Example 1 in which the electrode layer protrudes from the current collector and the secondary battery of Comparative Example 2 in which the area of the main surface of the current collector is equal to the electrode area, the charge / discharge cycle The service life was shorter than that of Reference Example 1.

(Example 2)
Resin sheets 14a and 14b of the same type as described in Reference Example 1 were prepared. The positive electrode current collector 4, the positive electrode layer 6, and the separator 8 were formed on the PE layer of the resin sheet 14a in the same manner as described in Reference Example 1, and the antenna 13 and the wirings 17 and 18 were formed by screen printing.

Further, the negative electrode current collector 5 and the negative electrode layer 5 were formed on the PE layer of the resin sheet 14b in the same manner as described in Reference Example 1.

After the separator 8 of the resin sheet 14a is dried, an electrolytic solution having the same composition as that described in Reference Example 1 is dropped thereon, and the negative electrode layer 5 of the resin sheet 14b is overlaid to form the electrode group 12. At the same time, the IC chip 11 was disposed between the resin sheets 14a and 14b. Subsequently, the resin sheets 14a and 14b around the IC chip 11 and the electrode group 12 were sealed by heat sealing, and the wireless IC tag having the structure shown in FIG. 4 was manufactured.

  The obtained IC tag could be used 6000 times or more at a communication distance of 500 cm.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

The typical top view showing one embodiment of the nonaqueous electrolyte battery of the present invention. FIG. 2 is a schematic cross-sectional view taken along the line II-II of the nonaqueous electrolyte battery in FIG. 1. The schematic diagram for demonstrating the manufacturing process of the nonaqueous electrolyte battery of FIG. The perspective view which showed typically one Embodiment of the battery mounting IC tag which concerns on this invention. Sectional drawing which cut | disconnected the IC tag of FIG. 4 along the VV line. Sectional drawing which cut | disconnected the IC tag of FIG. 4 along the VI-VI line. Sectional drawing which cut | disconnected the IC tag of FIG. 4 along the VII-VII line. Sectional drawing which cut | disconnected the IC tag of FIG. 4 along the VIII-VIII line. The perspective view which showed typically another embodiment of the IC tag. Sectional drawing which cut | disconnected the IC tag of FIG. 9 along the XX line The perspective view which showed still another embodiment of IC tag typically. Sectional drawing which cut | disconnected the IC tag of FIG. 11 along the XII-XII line. FIG. 4 is a schematic cross-sectional view showing a nonaqueous electrolyte battery of Comparative Example 2.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1a, 1b, 14a, 14b ... Resin-made sheet, 2,15 ... Thermoplastic resin film, 3,16 ... Resin film, 4 ... Positive electrode collector, 4a ... Positive electrode tab, 5 ... Negative electrode collector, 5a ... Negative electrode Tab, 6 ... Positive electrode layer, 7 ... Negative electrode layer, 8 ... Separator, 9 ... IC tag, 10 ... Exterior member, 11 ... IC chip, 12 ... Electrode group, 13 ... Antenna, 17-21 ... Wiring.

Claims (2)

A resin exterior member having an IC housing portion and an electrode group housing portion;
An IC chip housed in the IC housing portion of the exterior member;
A positive electrode current collector with a positive electrode tab formed on the inner surface of the electrode group housing portion of the exterior member;
A negative electrode current collector with a negative electrode tab formed on the inner surface of the electrode group housing portion so as to face the positive electrode current collector;
A positive electrode layer formed on the positive electrode current collector;
A negative electrode layer formed on the negative electrode current collector;
A separator disposed between the positive electrode layer and the negative electrode layer;
A non-aqueous electrolyte housed in the electrode group housing portion,
The position of the negative electrode tab is shifted from the position of the positive electrode tab, the positive electrode current collector protrudes from the periphery of the positive electrode layer, and the negative electrode current collector protrudes from the periphery of the negative electrode layer. IC tag with non-aqueous electrolyte battery. The separator contains ceramic particles,
The non-aqueous electrolyte battery mounted IC tag according to claim 1, wherein the negative electrode layer contains lithium titanate, and the negative electrode current collector is formed of aluminum or an aluminum alloy.

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