JP2013033632A - Bipolar battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that when low resistance conductive component is inserted between the current collector foil of a current collector and an anode active material layer in order to accurately measure the voltage of a bipolar battery, resistance increases that much.SOLUTION: In a bipolar battery composed of bipolar electrodes which have a cathode active material layer 12 formed on one side of a current collector 11 and an anode active material layer 13 formed on the other side and which are laminated one on another via an electrolyte layer 15, a voltage detection line 20 for voltage measurement is connected at a position, on any side of the anode active material layer 13 and the cathode active material layer 12, where one and the other of the layers do not face each other.

Description

  The present invention relates to a bipolar battery.

  A bipolar battery using a resin current collector has high conductivity in the thickness direction of the current collector, but has low conductivity in the surface direction. In Patent Document 1, in order to supplement the conductivity in the surface direction of the current collector, a low resistance conductive member is provided, and a voltage detection lead wire is connected to the low resistance conductive member. A technique for accurately measuring the voltage of a bipolar battery using a resin current collector is disclosed.

JP 2010-157449 A

  However, in the conventional technique, since a low-resistance conductive member is provided between the current collector foil of the current collector and the negative electrode active material layer, there is a problem that the resistance increases accordingly.

  An object of the present invention is to provide a technique for accurately measuring the voltage of a bipolar battery without providing a new member.

  The bipolar battery according to the present invention includes a bipolar electrode in which a positive electrode active material layer is formed on one surface of a current collector and a negative electrode active material layer is formed on the other surface through an electrolyte layer. It is composed by doing. A voltage detection line for measuring a voltage was connected to one of the negative electrode active material layer and the positive electrode active material layer at a position where one layer did not face the other layer.

  According to the present invention, since the voltage detection line is connected to a position which is one of the negative electrode active material layer and the positive electrode active material layer and does not affect the battery reaction, a new member is not provided. The battery voltage can be detected with high accuracy.

It is sectional drawing which shows schematic structure of the bipolar battery in the 1st Embodiment of this invention. It is a figure for demonstrating the connection location of a lead wire in the bipolar battery in 1st Embodiment. It is a figure which shows an example of a connection location when the connection location of a lead wire and a negative electrode active material layer is made into one location. It is a figure which shows an example of a connection location when the connection location of a lead wire and a negative electrode active material layer is made into 4 locations. It is a figure which shows an example of a connection location at the time of making the connection location of a lead wire and a negative electrode active material layer into many. It is a figure which shows the connection place of a lead wire in the bipolar battery in 2nd Embodiment.

<First Embodiment>
FIG. 1 is a cross-sectional view showing a schematic configuration of a bipolar battery according to the first embodiment of the present invention. The bipolar battery in this embodiment is a flat type (stacked type), for example, a lithium ion secondary battery. In the bipolar battery according to this embodiment, a lead wire is connected to the negative electrode active material layer 13 in order to monitor the voltage of the battery, but this is omitted in FIG.

  In the bipolar battery 10 according to the first embodiment shown in FIG. 1, a substantially rectangular power generation element (battery element; laminate) 17 in which a charge / discharge reaction actually proceeds is placed inside a laminate film 22 that is a battery exterior material. It has a sealed structure.

  As shown in FIG. 1, the power generation element 17 of the bipolar battery 10 according to the present embodiment has a positive electrode active material layer 12 electrically coupled to one surface of the current collector 11, and is opposite to the current collector 11. A plurality of bipolar electrodes having a negative electrode active material layer 13 electrically coupled thereto. Each bipolar electrode is stacked via an electrolyte layer 15 to form a power generation element 17.

  The electrolyte layer 15 has a configuration in which an electrolyte is held at the center in the surface direction of a separator as a base material. At this time, each bipolar type is formed such that the positive electrode active material layer 12 of one bipolar electrode and the negative electrode active material layer 13 of another bipolar electrode adjacent to the one bipolar electrode face each other through the electrolyte layer 15. Electrodes and electrolyte layers 15 are alternately stacked. That is, the electrolyte layer 15 is disposed between the positive electrode active material layer 12 of one bipolar electrode and the negative electrode active material layer 13 of another bipolar electrode adjacent to the one bipolar electrode.

  The adjacent positive electrode active material layer 12, electrolyte layer 15, and negative electrode active material layer 13 constitute one single battery layer (= battery unit or single cell) 16. Therefore, it can be said that the bipolar battery 10 has a configuration in which a plurality of single battery layers 16 are stacked.

  For the purpose of preventing liquid junction due to leakage of the electrolyte from the electrolyte layer 15, a seal portion (insulating layer) 23 is disposed on the outer peripheral portion of each unit cell layer 16. By providing the seal portion 23, the adjacent current collectors 11 can be insulated from each other, and a short circuit due to contact between the adjacent electrodes can be prevented. By installing such a seal portion 23, long-term reliability and safety are ensured, and a high-quality bipolar battery 10 can be provided.

  The outermost layer current collector 11a is disposed on the uppermost layer of the power generation element 17, and the outermost layer current collector 11b is disposed on the lowermost layer. The outermost layer current collector 11a has a positive electrode active material layer 12 formed only on one side, and the outermost layer current collector 11b has a negative electrode active material layer 13 formed only on one side. However, the positive electrode active material layer 12 may be formed on both surfaces of the outermost layer current collector 11a on the positive electrode side. Similarly, the negative electrode active material layer 13 may be formed on both surfaces of the outermost layer current collector 11b on the negative electrode side.

  The outermost layer current collectors 11 a and 11 b are led out of the battery exterior material 22 and constitute a positive electrode tab 18 and a negative electrode tab 19, respectively. However, the outermost layer current collector 11a is not extended, and the positive electrode current collector plate is disposed adjacent to the outermost layer current collector 11a on the positive electrode side, and this is extended and led out from the battery exterior material 22. Also good. Further, the outermost layer current collector 11b is not extended, and the negative electrode current collector plate is disposed adjacent to the negative electrode side outermost layer current collector 11b. Similarly, this is extended and led out from the battery exterior material 22. It is good also as a structure.

  Note that the number of stacks of the unit cell layers 16 is adjusted according to a desired voltage. In the bipolar battery 10, the number of times the single battery layer 16 is stacked may be reduced if a sufficient output can be ensured even if the battery is made as thin as possible. In the bipolar battery 10, the power generation element 17 is sealed in the battery exterior material 22 under reduced pressure in order to prevent external impact and environmental degradation during use. When the positive electrode current collector plate and the negative electrode current collector plate are provided, it is preferable to adopt a structure in which these are taken out of the battery exterior material 22. The outermost layer current collector may be made of metal or resin.

[Current collector]
Although the current collector 11 does not necessarily have conductivity, the current collector foil as a whole has conductivity in order to function as a current collector foil. The current collector 11 is a so-called resin current collector containing a polymer material.

  When the current collecting foil includes a polymer material that does not have conductivity, it naturally includes a conductive filler (conductive particles). The conductive filler is selected from materials that are conductive and have no conductivity with respect to the ions used as the charge transfer medium. The conductive filler is selected from materials that can withstand the applied positive electrode potential and negative electrode potential. Specific examples include aluminum particles, SUS particles, carbon particles, silver particles, gold particles, copper particles, and titanium particles, but are not limited thereto. Alloy particles may be used. The conductive filler is not limited to metal, and carbon particles, carbon nanotubes, and the like are used. Moreover, what is put into practical use as a so-called filler-based conductive resin composition can be used. Among these, a material usually used as a conductive aid in a battery is preferable, and carbon particles are preferable. Carbon particles such as carbon black and graphite have a very wide potential window. Therefore, it is stable in a wide range with respect to both the positive electrode potential and the negative electrode potential, and further has excellent conductivity. Also, since the carbon particles are very light, the increase in mass is minimized.

  The distribution of the conductive filler in the current collector foil may not be uniform, and the particle distribution may vary within the current collector foil. A plurality of conductive particles may be used, and the distribution of the conductive particles may be changed inside the current collector. For example, a preferable conductive filler may be properly used in a portion in contact with the positive electrode and a portion in contact with the negative electrode. As the conductive filler used on the positive electrode side, aluminum particles, SUS particles, and carbon particles are preferable, and carbon particles are particularly preferable. As the conductive filler used for the negative electrode, silver particles, gold particles, copper particles, titanium particles, SUS particles, and carbon particles are preferable, and carbon particles are particularly preferable. Furthermore, since carbon particles are often used as a conductive aid for electrodes, even if they come into contact with these conductive aids, the contact resistance is very low because of the same material.

  Although the preferable magnitude | size of an electroconductive filler is not restrict | limited in particular, The thing of about several hundred nm-several dozen micrometer can be used in general. The particle size is preferably 0.1 to 50 μm, more preferably 1 to 20 μm, and still more preferably 1 to 3 μm. Furthermore, the shape of the conductive filler is not particularly limited, and may be fibrous, plate-like, or massive.

  When the conductive filler is used, the current collector foil includes a polymer material that binds the conductive filler in addition to the conductive filler. By using a polymer material as a constituent material of the current collector foil, the binding property of the conductive filler can be increased and the reliability of the battery can be increased. The polymer material is selected from materials that can withstand the applied positive electrode potential and negative electrode potential.

The polymer material not having conductivity is preferably polyethylene, polypropylene, polyethylene terephthalate, polyacrylonitrile, polyether nitrile, polymethyl acrylate, polymethyl methacrylate, polyamide, polyimide, cellulose, carboxymethyl cellulose, ethylene-vinyl acetate. Polymer, polyvinyl chloride, styrene / butadiene rubber, isoprene rubber, butadiene rubber, ethylene / propylene rubber, ethylene / propylene / diene copolymer, styrene / butadiene / styrene block copolymer and its hydrogenated product, styrene / isoprene -Thermoplastic polymers such as styrene block copolymers and their hydrogenated products, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol 1, 3-butylene glycol, polyvinyl alcohol, polyvinyl propynal, polyvinyl butyral, polyacrylamide, polyethylene glycol, polypropylene glycol, polybutylene glycol and other hydroxyl group-containing compounds, polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), ethylene / tetrafluoroethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), fluoropolymers such as ethylene / chlorotrifluoroethylene copolymer (ECTFE), polyvinyl fluoride (PVF), vinylidene fluoride Do-hexafluoropropylene fluorine rubber (VDF-HFP fluorine rubber), vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene fluorine rubber (VDF-HFP-TFE fluorine rubber), vinylidene fluoride-pentafluoropropylene Fluoro rubber (VDF-PFP fluorine rubber), vinylidene fluoride-pentafluoropropylene-tetrafluoroethylene fluorine rubber (VDF-PFP-TFE fluorine rubber), vinylidene fluoride-perfluoromethyl vinyl ether-tetrafluoroethylene fluorine Vinylidene fluoride such as rubber (VDF-PFMVE-TFE fluoro rubber), vinylidene fluoride-chlorotrifluoroethylene fluoro rubber (VDF-CTFE fluoro rubber), etc. And fluorocarbon rubber. These polymer materials may be used alone or in combination of two or more.

  These polymer materials have a very wide potential window, are stable in a wide range with respect to both the positive electrode potential and the negative electrode potential, and can improve the adhesion to the active material layer. More preferably, polypropylene and polyethylene are used as the polymer material. These are versatile, easy to handle and easy to obtain.

  The distribution of the polymer material in the current collector foil may not be uniform, and the distribution of the polymer material may be changed inside the current collector foil. A plurality of polymer materials may be used, and the distribution of the polymer material may be changed inside the current collector foil. For example, a preferable polymer material may be properly used for a portion in contact with the positive electrode and a portion in contact with the negative electrode. The current collector foil may contain other materials as necessary.

  The ratio between the polymer material and the conductive particles in the current collector foil is not particularly limited. It adjusts suitably so that it may become an appropriate volume resistivity.

  When carbon particles are used as the conductive filler, it is preferable to use 3 to 40% by mass of carbon particles with respect to the total of the polymer material and the conductive filler. However, it adjusts suitably so that it may become an appropriate volume resistivity.

  The presence of the conductive filler in the current collector foil is not always necessary, and the polymer itself may have conductivity. That is, a film made of a conductive polymer (also referred to as “conductive polymer” in this specification) can be used as a current collector.

  The conductive polymer is selected from materials that are conductive and have no conductivity with respect to ions used as charge transfer media. These conductive polymers are considered to be conductive because the conjugated polyene system forms an energy band. As a typical example, a polyene-based conductive polymer that has been put into practical use in an electrolytic capacitor or the like can be used. Specific examples include polyaniline, polypyrrole, polythiophene, polyacetylene, polyparaphenylene, polyphenylene vinylene, polyacrylonitrile, polyoxadiazole, or a mixture thereof.

  The thickness of the current collector is not particularly limited, and any current collector having a thickness normally used for batteries can be used. As for the thickness of the electrical power collector containing a normal polymeric material, 50-200 micrometers is preferable, More preferably, it is 30-150 micrometers, More preferably, it is 10-100 micrometers. Here, it is preferable that the current collector is generally thin from the viewpoint of increasing the output density of the battery.

As for the conductivity of the current collector foil, the volume resistivity is preferably 10 ⁻² to 10 ² Ω · cm. In order to ensure the performance required for practical use as a bipolar battery, the volume resistivity is preferably 10 ² Ω · cm or less. On the other hand, it is particularly low conductivity in the surface direction of the current collector foil, because there is also an advantage that avoids the concentration of the surface through the efficient current in the thickness direction direction current, the capitalize on this characteristic 10 ^- It is preferably not less than ² Ω · cm.

[Active material layer]
An active material layer serving as an electrode is formed on the current collector. The active material layer is a layer containing an active material that plays a central role in the charge / discharge reaction. When the electrode is used as a positive electrode, the active material layer includes a positive electrode active material. On the other hand, when the electrode is used as a negative electrode, the active material layer includes a negative electrode active material.

For example, if the battery is the lithium ion secondary battery, lithium - transition metal composite oxides are preferable as the cathode active material, Li · Co-based composite oxide such as LiCoO _2, Li · Ni such as LiNiO ₂ And Li / Mn composite oxides such as spinel LiMn ₂ O ₄ and Li / Fe composite oxides such as LiFeO ₂ . In addition, transition metal and lithium phosphate compounds and sulfuric acid compounds such as LiFePO ₄ ; transition metal oxides and sulfides such as V ₂ O ₅ , MnO ₂ , TiS ₂ , MoS ₂ , and MoO ₃ ; PbO ₂ , AgO, NiOOH etc. are mentioned. In some cases, two or more positive electrode active materials may be used in combination.

  A carbon material is preferable as the negative electrode active material. Examples of the carbon material include graphite-based carbon materials (graphite) such as natural graphite, artificial graphite, and expanded graphite, carbon black, activated carbon, carbon fiber, coke, soft carbon, and hard carbon. More preferably, graphite such as natural graphite, artificial graphite, and expanded graphite. As natural graphite, for example, scaly graphite, massive graphite and the like can be used. As the artificial graphite, massive graphite, vapor-grown graphite, flaky graphite, and fibrous graphite can be used. Among these, particularly preferable materials are flake graphite and massive graphite. The use of flaky graphite or massive graphite is particularly advantageous for reasons such as high packing density. In some cases, two or more negative electrode active materials may be used in combination.

  The average particle diameter of the active material is not particularly limited, but is preferably 1 to 100 μm, more preferably 1 to 50 μm, and further preferably 1 to 20 μm. However, forms outside these ranges can also be employed. In this application, the average particle diameter of the active material is a value measured by laser diffraction particle size distribution measurement (laser diffraction scattering method).

  Moreover, the content of the active material in the active material layer is preferably 70 to 98% by mass, more preferably 80 to 98% by mass with respect to the total mass of the active material layer. If the content of the active material is in the above range, it is preferable because the energy density can be increased.

  In the electrode of the present embodiment, the thickness of the active material layer (the thickness of one surface of the coating layer) is preferably 20 to 500 μm, more preferably 20 to 300 μm, and further preferably 20 to 150 μm. is there.

The volume resistivity of the negative electrode active material layer 13 is preferably 10 ⁻⁴ to 10 ⁻² Ω · cm. This is because, as will be described later, a lead wire is connected to the negative electrode active material layer 13 in order to monitor the voltage of the battery, but the voltage is monitored accurately.

  The active material layer may contain other materials, for example, a binder, a conductive additive, a supporting salt (lithium salt), and the like. The compounding ratio of these components is not particularly limited, and can be adjusted by appropriately referring to known knowledge about the bipolar battery.

  The binder contained in the active material layer includes polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polyether nitrile (PEN), polyimide (PI), polyamide (PA), polytetrafluoroethylene (PTFE). Styrene butadiene rubber (SBR), polyacrylonitrile (PAN), polymethyl acrylate (PMA), polymethyl methacrylate (PMMA), polyvinyl chloride (PVC), polyvinylidene fluoride (PVdF), or mixtures thereof.

  A conductive assistant means the additive mix | blended in order to improve electroconductivity. Examples of the conductive assistant include carbon powder such as graphite, and various carbon fibers such as vapor grown carbon fiber (VGCF). The supporting salt is the same as that used for the electrolyte layer described later.

[Electrolyte layer]
As the electrolyte constituting the electrolyte layer, a porous film separator containing an electrolytic solution or a gel electrolyte can be used. The electrolytic solution is in a form in which a lithium salt or the like as a supporting salt is dissolved in an organic solvent.

  Any organic solvent can be used as long as it can sufficiently dissolve the supporting salt. For example, cyclic carbonates such as propylene carbonate and ethylene carbonate; chain carbonates such as dimethyl carbonate, methyl ethyl carbonate, and diethyl carbonate; tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane, 1 Selected from among ethers such as 1,2-dibutoxyethane; lactones such as γ-butyrolactone; nitriles such as acetonitrile; esters such as methyl propionate; amides such as dimethylformamide; methyl acetate and methyl formate The thing using the plasticizer (organic solvent), such as an aprotic solvent, which mixed at least 1 type or 2 types or more can be used. These organic solvents may be used alone or in combination of two or more.

Conventionally known salts can be used as the supporting salt. Specific examples include Li (C ₂ F ₅ SO ₂ ) ₂ N (LiBETI), LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAsF ₆ , LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, Li (C ₂ F ₅ SO ₂ ) ₂ N and the like.

  Moreover, as a specific form of a separator, the microporous film which consists of polyolefin, such as polyethylene and a polypropylene, is mentioned, for example.

  The gel electrolyte has a configuration in which an electrolytic solution is injected into a matrix polymer made of an ion conductive polymer. Examples of the ion conductive polymer used as the matrix polymer include polyethylene oxide (PEO), polypropylene oxide (PPO), polyethylene glycol (PEG), polyacrylonitrile (PAN), and vinylidene fluoride-hexafluoropropylene (VDF-HEP). And poly (methyl methacrylate (PMMA), copolymers thereof, etc. In such polyalkylene oxide polymers, electrolyte salts such as lithium salts can be well dissolved.

[Battery exterior materials]
As a battery exterior material, a conventionally known metal can case can be used, and a bag-like case that can cover a power generation element using a laminate film containing aluminum can be used. For example, a laminate film having a three-layer structure in which polypropylene, aluminum, and nylon (registered trademark) are laminated in this order can be used as the laminate film, but the laminate film is not limited thereto.

[Lead]
Although omitted in FIG. 1, in the bipolar battery in this embodiment, a lead wire (voltage detection line) is connected to the negative electrode active material layer 13 in order to monitor the voltage of the battery. This lead wire is connected to, for example, a controller (not shown) provided outside the bipolar battery 10.

  FIG. 2 is a diagram for explaining a connection portion of the lead wire 20 in the bipolar battery 10 according to the first embodiment. In the bipolar battery 10 according to the first embodiment, the negative electrode active material layer 13 is larger than the positive electrode active material layer 12 so that there is a position that does not face the positive electrode active material layer 12 at the end of the negative electrode active material layer 13. In addition, the lead wire 20 is connected to a position that does not face the positive electrode active material layer 12 in the negative electrode active material layer 13. By connecting the lead wire 20 to a position in the negative electrode active material layer 13 that does not face the positive electrode active material layer 12, the voltage of each cell can be detected with high accuracy without affecting the battery reaction.

  The lead wire 20 is connected to the negative electrode active material layer 13 of the cell whose voltage is to be detected. Therefore, when detecting the voltage of each cell, the lead wire 20 is connected to the negative electrode active material layer 13 of each cell.

  Here, the connection point between the lead wire 20 and the negative electrode active material layer 13 is inside the power generation element 17 sealed by the seal portion 23. For this reason, the lead wire 20 is made of an electrochemically inactive material in the potential range where the negative electrode functions, so that the lead wire 20 does not react with the electrolyte. Examples of such a material include Cu (copper), Ni (nickel), and SUS (stainless steel).

  In addition, the structure which covers the part which does not oppose the positive electrode active material layer 12 among the negative electrode active material layers 13 with the seal | sticker part 23 or another insulator is also considered. In such a case, the lead wire 20 may be connected to a position of the negative electrode active material layer 13 that is covered with the seal portion 23 or another insulator. In this case, since the lead wire 20 does not react with the electrolyte, the material of the lead wire 20 is limited to the above-mentioned “material that is electrochemically inactive in the potential range where the negative electrode functions”. You can choose from a wide range of materials.

  Moreover, although the example which uses the porous film separator or gel electrolyte containing electrolyte solution was given as an electrolyte which comprises the electrolyte layer 15, a solid electrolyte can also be used. In this case, since the fluidity of the electrolyte is lost, it is not necessary to consider the contact between the lead wire 20 and the electrolyte. That is, the material of the lead wire 20 is not limited to the above-described “material that is electrochemically inactive in the potential range where the negative electrode functions”, and can be selected from a wide range of materials.

Examples of the solid electrolyte include known polymer solid electrolytes such as PEO, PPO, and copolymers thereof, and inorganic solid electrolytes having ion conductivity such as ceramic. The solid polymer electrolyte contains a lithium salt to ensure ionic conductivity. The lithium _{salt, LiPF 6, LiBF 4, LiClO} 4, LiAsF 6, LiTaF 6, LiSbF 6, LiAlCl 4, Li 2 B 10 Cl 10, LiI, LiBr, LiCl, LiAlCl, LiHF 2, inorganic acid anions such as LiSCN Ionic salt, LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, LiBOB (lithium bisoxide borate), LiBETI (lithium bis (perfluoroethylenesulfonylimide); Li (C ₂ F ₅ SO ₂ ) ₂ N Organic acid anion salts, etc.). _{Preferably, LiBF 4, LiPF 6, LiN} (SO 2 CF 3) 2, LiN (SO 2 C 2 F 5) 2 can be used. In addition, the said lithium salt may be used independently or may be used with the form of 2 or more types of mixtures.

  FIG. 3 is a diagram illustrating an example of a connection location where the connection location between the lead wire 20 and the negative electrode active material layer 13 is one location. However, the connection location between the lead wire 20 and the negative electrode active material layer 13 is not limited to one location. FIG. 4 is a diagram illustrating an example of connection points when the number of connection points between the lead wire 20 and the negative electrode active material layer 13 is four. That is, a total of four lead wires 20 are connected to four locations of one negative electrode active material layer 13. Also in this case, each lead wire 20 is connected to a position in the negative electrode active material layer 13 that does not face the positive electrode active material layer 12.

  FIG. 5 is a diagram illustrating an example of connection points when the number of connection points between the lead wire 20 and the negative electrode active material layer 13 is large. In the example shown in FIG. 5, the lead wire 20 is connected to the entire outer periphery of the negative electrode active material layer 13 that does not face the positive electrode active material layer 12. As shown in FIGS. 4 and 5, if the number of connection points between the lead wire 20 and the negative electrode active material layer 13 is two or more, the voltage of the battery is more accurate than the case where the number of connection points is one. Can be detected. That is, by using a plurality of connection locations, an average voltage can be measured even when the potential varies depending on the connection locations.

[Battery]
An assembled battery can be configured by connecting a plurality of bipolar batteries in this embodiment in series or in parallel. By connecting bipolar batteries in series or in parallel, the capacity and voltage can be freely adjusted. Such an assembled battery can be used, for example, as a driving power source for an electric vehicle or a hybrid vehicle.

  As described above, in the bipolar battery according to the first embodiment, the lead wire 20 for measuring the voltage is connected to the position of the negative electrode active material layer 13 that does not face the positive electrode active material layer 12. The battery voltage can be accurately measured without affecting the above. Further, since the lead wire 20 is directly connected to the negative electrode, the voltage of the battery can be accurately measured without being affected by the resistance of the current collector 11 as compared with the case where the lead wire 20 is connected to the current collector 11. be able to.

  Here, the structure which connects the lead wire 20 to the positive electrode active material layer 12 like 2nd Embodiment mentioned later is also considered. However, since the negative electrode active material layer 13 has higher conductivity than the positive electrode active material layer 12, the configuration in which the lead wire 20 is connected to the negative electrode active material layer 13 can measure the voltage more accurately. it can.

  In addition, since the lead wire 20 is made of an electrochemically inactive material in the potential range where the electrode functions, it is possible to prevent the lead wire 20 from reacting with the electrolytic solution.

  Further, when a solid electrolyte layer is used as the electrolyte layer 15, the lead wire 20 can be prevented from coming into contact with the electrolyte, so that the material of the lead wire 20 can be selected from a wide range of materials.

  Furthermore, when a plurality of lead wires 20 are connected to a plurality of positions in the negative electrode active material layer 13 that do not face the positive electrode active material layer 12, the accuracy is higher than when the lead wires 20 are connected to one location. Well, the battery voltage can be detected.

<Second Embodiment>
In the bipolar battery according to the first embodiment, the negative electrode active material layer 13 is made larger than the positive electrode active material layer 12 so that there is a position not facing the positive electrode active material layer 12. A lead wire 20 was connected to a position not facing the active material layer 12. In the bipolar battery according to the second embodiment, the positive electrode active material layer 12 is made larger than the negative electrode active material layer 13 so that there is a position that does not face the negative electrode active material layer 13. The lead wire 20 is connected to a position that does not face the active material layer 13.

  The cross-sectional view of the bipolar battery in the second embodiment is the same as the cross-sectional view of the bipolar battery in the first embodiment shown in FIG. Further, the positive electrode active material layer 12 is made larger than the negative electrode active material layer 13 so that there is a position that does not face the negative electrode active material layer 13, and the positive electrode active material layer 12 is located at a position that does not face the negative electrode active material layer 13. The configuration other than the configuration in which the lead wire 20 is connected is the same as the bipolar battery in the first embodiment.

  FIG. 6 is a diagram showing the connection location of the lead wire 20 in the bipolar battery according to the second embodiment. As shown in FIG. 6, the positive electrode active material layer 12 is larger than the negative electrode active material layer 13 and there is a position that does not face the negative electrode active material layer 13. By connecting the lead wire 20 to a position of the positive electrode active material layer 12 that does not face the negative electrode active material layer 13, the voltage of each cell can be detected with high accuracy without affecting the battery reaction.

  As described above, in the bipolar battery according to the second embodiment, the lead wire 20 for measuring the voltage is connected to a position of the positive electrode active material layer 12 that does not face the negative electrode active material layer 13. The battery voltage can be accurately measured without affecting the above. Further, since the lead wire 20 is directly connected to the positive electrode, the voltage of the battery is measured with high accuracy without being affected by the resistance of the current collector 11 as compared with the case where the lead wire 20 is connected to the current collector 11. be able to.

  The present invention is not limited to the first and second embodiments described above. For example, in the above-described embodiment, the current collector has been described as a resin current collector containing a polymer material, but is not limited to the resin current collector.

DESCRIPTION OF SYMBOLS 10 ... Bipolar battery 11 ... Current collector 12 ... Positive electrode active material layer 13 ... Negative electrode active material layer 15 ... Electrolyte layer 20 ... Lead wire

Claims (6)

Bipolar type formed by laminating a bipolar electrode having a positive electrode active material layer formed on one surface of a current collector and a negative electrode active material layer formed on the other surface via an electrolyte layer A battery,
A voltage detection line for measuring a voltage is connected to one of the negative electrode active material layer and the positive electrode active material layer, and the one layer does not face the other layer. A bipolar battery characterized by The one layer is the negative electrode active material layer.
The bipolar battery according to claim 1. The voltage detection line is electrochemically inactive in a potential range where the electrode functions.
The bipolar battery according to claim 1 or 2, wherein the battery is a bipolar battery. The electrolyte layer is a solid electrolyte layer;
The bipolar battery according to claim 1 or 2, wherein the battery is a bipolar battery.   A plurality of the voltage detection lines are connected to a position of any one of the negative electrode active material layer and the positive electrode active material layer, wherein the one layer does not face the other layer. The bipolar battery according to any one of claims 1 to 4. The volume resistivity of the current collector foil is 10 ⁻² to 10 ² Ω · cm.
The bipolar battery according to any one of claims 1 to 5, wherein the battery is a bipolar battery.

Images