JP5540575B2 - Current collector for bipolar secondary battery, bipolar secondary battery, assembled battery, vehicle, control device for bipolar secondary battery, and control method for bipolar secondary battery - Google Patents

Description

  The present invention relates to a current collector for a bipolar secondary battery.

  There is a demand for higher output density and higher capacity density of the battery, and it is necessary to reduce the weight of the battery. For example, even in a bipolar secondary battery, there is a technique including a current collector including a conductive resin layer for weight reduction (Patent Document 1).

JP 2006-190649 A

  However, when a conductive resin is used as the current collector, the resistance value is higher than that of the metal, so that heat is easily generated.

  Accordingly, an object of the present invention is to provide a current collector for a bipolar secondary battery that can suppress an increase in temperature.

  Another object of the present invention is to provide a bipolar secondary battery that can suppress an increase in battery temperature. Moreover, it is providing the assembled battery using such a bipolar secondary battery, the vehicle using them, those control apparatuses, and a control method.

In order to achieve the above object, the present invention provides a bipolar secondary battery in which a first electrode is provided on a first surface and a second electrode having a polarity different from that of the first electrode is provided on a second surface opposite to the first surface. Current collector. The current collector includes a first conductive resin portion whose electrical resistance increases when the temperature rises and reaches a predetermined temperature, and an increase in electrical resistance even when the temperature rises to the predetermined temperature. seen containing a second conductive resin portion less than the part, a continuous first conductive resin portion and the second conductive resin portion, respectively, to a surface facing the second electrode from the surface facing the first electrode Extended .
Further, according to the present invention for achieving the above object, the first conductive resin portion and the second conductive resin portion are arranged in a direction perpendicular to the thickness direction between the first electrode and the second electrode. Placed in.

  The current collector of the bipolar secondary battery of the present invention has a first conductive resin portion whose resistance value rapidly increases at a predetermined temperature and a second conductive resin portion whose resistance value does not increase rapidly at the predetermined temperature. Even if the temperature in the battery rises to the temperature, the current can be passed through the second conductive resin portion. Therefore, current can be prevented from flowing through the first conductive resin portion having a high resistance, so that heat generation at the current collector can be suppressed.

It is a section schematic diagram showing the structure of a bipolar secondary battery. It is the schematic which represented the electrical power collector of 1st Embodiment typically. It is the schematic which represented the modification of the electrical power collector of 1st Embodiment typically. It is the schematic diagram which showed the mode of the electric current which flows into a bipolar secondary battery. It is a figure showing the relationship between the temperature of the electrical power collector of 1st Embodiment, and resistance. It is a figure showing the relationship between resin and electrically conductive material by the temperature change of the electrical power collector of 1st Embodiment. It is a perspective view showing the appearance of a bipolar secondary battery. It is an external view of an assembled battery. It is a conceptual diagram of the vehicle carrying an assembled battery. It is a block diagram of the system which detects the temperature of a bipolar secondary battery and implements current limitation. It is a flowchart figure of the method of detecting the temperature of a bipolar secondary battery and implementing current limiting. FIG. 6 is a relationship diagram between a current in which the temperature of a bipolar secondary battery is detected and current limiting is performed and the temperature in the battery. It is a block diagram of the system which detects the electric current from a bipolar secondary battery and implements current limitation. It is a flowchart figure of the method of detecting the electric current from a bipolar type secondary battery, and implementing an electric current limitation. FIG. 6 is a relationship diagram between a current in which a current from a bipolar secondary battery is detected and current limiting is performed and a temperature in the battery. It is the schematic which represented the electrical power collector of 2nd Embodiment typically. It is the schematic which represented typically how the electric current flows in 2nd Embodiment. It is the schematic which represented the electrical power collector of 7th Embodiment typically. It is the schematic which represented the electrical power collector of 8th Embodiment typically.

  First, a bipolar secondary battery (bipolar lithium ion secondary battery), which is a preferred embodiment, will be described, but is not limited to the following embodiments. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. In addition, the dimensional ratios in the drawings are exaggerated for convenience of explanation, and may be different from the actual ratios.

  When distinguished by the structure and form of the bipolar secondary battery, it is not particularly limited, such as a stacked (flat) battery or a wound (cylindrical) battery, and can be applied to any conventionally known structure.

  Similarly, there is no particular limitation even when distinguished by the electrolyte form of the bipolar secondary battery. For example, the present invention can be applied to any of a liquid electrolyte type battery in which a separator is impregnated with a nonaqueous electrolytic solution, a polymer gel electrolyte type battery also called a polymer battery, and a solid polymer electrolyte (all solid electrolyte) type battery. With respect to the polymer gel electrolyte and the solid polymer electrolyte, these can be used alone, or the polymer gel electrolyte or the solid polymer electrolyte can be used by impregnating the separator.

  Moreover, when it sees in the electrode material of a battery, or the metal ion which moves between electrodes, it does not restrict | limit in particular, It can apply to any well-known electrode material. Examples include lithium ion secondary batteries, sodium ion secondary batteries, potassium ion secondary batteries, nickel metal hydride secondary batteries, nickel cadmium secondary batteries, nickel metal hydride batteries, and the like, preferably lithium ion secondary batteries. . This is because in the lithium ion secondary battery, the voltage of the cell (single cell layer) is large, high energy density and high output density can be achieved, and it is excellent as a vehicle driving power source or an auxiliary power source.

(First embodiment)
FIG. 1 is a schematic cross-sectional view schematically showing the entire structure of the bipolar secondary battery 10. As shown in FIG. 1, the bipolar secondary battery 10 has a structure in which a substantially rectangular power generation element 21 in which a charge / discharge reaction actually proceeds is sealed inside a laminate film 29 that is a battery exterior material. The power generation element 21 of the bipolar secondary battery 10 is formed with a first electrode electrically coupled to one surface (first surface) of the current collector 11, and a surface on the opposite side (second surface) of the current collector 11. A plurality of bipolar electrodes 23 having a second electrode electrically coupled to the surface. The first electrode is, for example, a positive electrode and includes a positive electrode active material layer 13, and the second electrode is, for example, a negative electrode and includes a negative electrode active material layer 15.

  Each bipolar electrode 23 is laminated via the electrolyte layer 17 to form the power generation element 21. The electrolyte layer 17 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, the positive electrode active material layer 13 of one bipolar electrode 23 and the negative electrode active material layer 15 of another bipolar electrode 23 adjacent to the one bipolar electrode 23 face each other through the electrolyte layer 17. The bipolar electrodes 23 and the electrolyte layers 17 are alternately stacked. That is, the electrolyte layer 17 is interposed between the positive electrode active material layer 13 of one bipolar electrode 23 and the negative electrode active material layer 15 of another bipolar electrode 23 adjacent to the one bipolar electrode 23. ing.

  The adjacent positive electrode active material layer 13, electrolyte layer 17, and negative electrode active material layer 15 constitute one unit cell layer 19. Therefore, it can be said that the bipolar secondary battery 10 has a configuration in which the single battery layers 19 are stacked. Further, for the purpose of preventing liquid junction due to leakage of the electrolytic solution from the electrolyte layer 17, a seal portion (insulating layer) 31 is disposed on the outer peripheral portion of the unit cell layer 19. A positive electrode active material layer 13 is formed only on one side of the positive electrode outermost layer current collector 11 a located in the outermost layer of the power generation element 21. The negative electrode active material layer 15 is formed only on one surface of the outermost current collector 11b on the negative electrode side located in the outermost layer of the power generation element 21. However, the positive electrode active material layer 13 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 15 may be formed on both surfaces of the outermost layer current collector 11b on the negative electrode side.

  Further, in the bipolar secondary battery 10 shown in FIG. 1, a positive electrode current collector plate 25 is disposed so as to be adjacent to the outermost layer current collector 11a on the positive electrode side, and this is extended to form a laminate film 29 which is a battery exterior material. Derived. On the other hand, the negative electrode current collector plate 27 is disposed so as to be adjacent to the outermost layer current collector 11b on the negative electrode side, and similarly, this is extended and led out from the laminate film 29 which is an exterior of the battery.

  In the bipolar secondary battery 10 shown in FIG. 1, an insulating part 31 is usually provided around each single battery layer 19. The insulating part 31 prevents the adjacent current collectors 11 in the battery from coming into contact with each other and a short circuit caused by a slight irregularity at the end of the unit cell layer 19 in the power generation element 21. Provided. By installing such an insulating part 31, long-term reliability and safety are ensured, and a high-quality bipolar secondary battery 10 can be provided.

  Note that the number of stacks of the unit cell layers 19 is adjusted according to a desired voltage. Further, in the bipolar secondary battery 10, the number of stacking of the single battery layers 19 may be reduced if a sufficient output can be secured even if the thickness of the battery is made as thin as possible. Even in the bipolar secondary battery 10, in order to prevent external impact and environmental degradation during use, the power generation element 21 is sealed under reduced pressure in a laminate film 29 that is a battery exterior material, and the positive electrode current collector plate 25 and the negative electrode current collector 25. A structure in which the electric plate 27 is taken out of the laminate film 29 is preferable.

  Hereinafter, main components of the bipolar secondary battery of this embodiment will be described.

  FIG. 2 is a schematic diagram schematically showing the current collector 11 of the bipolar secondary battery 10 according to the first embodiment. FIG. 3 is a schematic view schematically showing a modification of the current collector 11 of the bipolar secondary battery 10 in the first embodiment.

  The current collector includes a conductive resin layer. As shown in FIG. 2, the current collector 11 has a first conductive resin portion 71 and a second conductive resin portion 72. In FIG. 2, the first conductive resin portion 71 and the second conductive resin portion 72 are arranged side by side between the electrodes. However, as shown in FIGS. 3A and 3B, the first conductive resin portion 71 and the second conductive resin portion 72 are arranged. The conductive resin portion 72 may be arranged evenly. The first conductive resin portion 71 is configured by mixing the first conductive material 71b with the first resin 71a. Similarly, the second conductive resin portion 72 is configured by mixing the second conductive material 72b with the second resin 72a.

  FIG. 4 is a schematic diagram showing a state of current flowing in the bipolar secondary battery. As shown in FIG. 4, the current repeatedly and sequentially flows from the negative electrode active material layer 15 to the electrolyte layer 17, the positive electrode active material layer 13, the current collector 11, and the negative electrode active material layer 15. Then, current is taken out from the positive electrode current collector plate 25. Since the current collector 11 is disposed so as to be interposed between different electrodes, the current easily flows in the direction in which the electrodes are stacked (the vertical direction of the electrode surface). Here, in a bipolar secondary battery using a metal current collector mainly composed of a metal, even if there is a variation in electric resistance in the surface of a battery component (for example, a separator), the surface of the metal current collector When the current flows in the direction, the current flows so as to avoid a portion having high resistance, and local heat generation does not occur. However, the bipolar secondary battery 10 using the current collector 11 composed of the first conductive resin portion 71 and the second conductive resin portion 72 configured by mixing a resin and a conductive material has a surface compared to a metal current collector. High inward electrical resistance. Therefore, when the first and second conductive resin portions 71 and 72 are used as a current collector of a bipolar secondary battery, current continues to flow to a portion where the resistance of the battery component is high, and local heat generation may occur. However, if there is a high resistance part and a low resistance part in the resin current collector through which the current flows, the current will continue to flow to the low part, and the low part may be gathered locally or many low parts may be provided. If this is the case, local heat generation is avoided.

  FIG. 5 is a diagram illustrating the relationship between the temperature and resistance of the first conductive resin portion 71 and the second conductive resin portion 72 included in the current collector 11 of the bipolar secondary battery 10 according to the first embodiment. As shown in FIG. 5, when the temperature of each resin portion increases, the resistance gradually increases. When the temperature of the resin portion rises to a certain predetermined temperature, the resistance of the first conductive resin portion 71 increases rapidly. However, the resistance of the second conductive resin portion 72 does not increase rapidly at a predetermined temperature at which the resistance of the first conductive resin portion 71 has rapidly increased. The resistance of the second conductive resin portion 72 increases abruptly at a second predetermined temperature at which the temperature has further increased.

  FIG. 6 is a diagram schematically showing changes in the resin and the conductive material when the temperature of the resin portion rises. As shown in FIG. 6, since the conductive material was in contact before the temperature rose, the current passed through the percolation path. However, when the temperature rises to a predetermined temperature, the resin expands, and the percolation path d is cut (separated) as the distance between the conductive material increases. As a result, in the percolation path where current has flowed until now, the current does not flow because the percolation path d is cut off.

  Therefore, when the temperature of the resin portion rises and reaches a predetermined temperature, many percolation paths are cut off, so that current hardly flows and resistance increases rapidly. In other words, in a bipolar secondary battery including a current collector that has only one resin portion in which a resistance value increases rapidly when the temperature exceeds a predetermined temperature and a conductive material mixed, the The current cannot be extracted. However, in the bipolar secondary battery 10 including the current collector 11 having the first conductive resin portion 71 and the second conductive resin portion 72 having different temperatures when the resistance value rapidly increases as shown in FIG. The battery function can be maintained by taking out current from the conductive resin portion 72. This is because, when the temperature rises to a predetermined temperature, even if the resistance value of the first conductive resin portion 71 suddenly increases and the percolation path is cut off, the resistance value of the second conductive resin portion 72 remains unchanged and the percolation path is not cut off. This is because current does not flow in the first conductive resin portion 71, but current flows in the second conductive resin portion 72. Therefore, it is possible to suppress a current flowing through the current collector 11 having the first conductive resin portion 71 and the second conductive resin portion 72 having different temperatures when the resistance value increases rapidly. And since the flow of an electric current can be suppressed, the heat_generation | fever of a battery is suppressed.

  Furthermore, the material which comprises this electrical power collector is demonstrated in detail.

(Current collector)
The current collector includes a conductive resin layer. For the resin layer to have conductivity, specific forms include a form in which the resin layer includes a resin and a conductive material (conductive filler), and a form in which the polymer material constituting the resin is a conductive polymer. It is done. From the viewpoint that a resin and a conductive material can be selected, a form in which the resin layer includes a resin and a conductive material is more preferable.

  First, a mode in which the polymer material constituting the resin is a conductive polymer will be described. 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. Specifically, polyaniline, polypyrrole, polythiophene, polyacetylene, polyparaphenylene, polyphenylene vinylene, polyacrylonitrile, polyoxadiazole, or a mixture thereof is preferable. Polyaniline, polypyrrole, polythiophene, and polyacetylene are more preferable from the viewpoints of electron conductivity and stable use in the battery.

  Next, the form in which the resin layer, which is a preferred form, includes a resin and a conductive material will be described in detail. The conductive material (conductive filler) is selected from conductive materials. Preferably, from the viewpoint of suppressing ion permeation in the resin layer having conductivity, it is desirable to use a material that does not have conductivity with respect to ions used as the charge transfer medium.

  Specific examples of the conductive material include aluminum materials, stainless steel (SUS) materials, carbon materials such as graphite and carbon black, silver materials, gold materials, copper materials, and titanium materials, but are not limited thereto. Absent. These conductive materials may be used alone or in combination of two or more. Moreover, these alloy materials may be used. Silver material, gold material, aluminum material, stainless steel material, carbon material is preferable, and carbon material is more preferable. These conductive materials may be those obtained by coating a conductive material (the above-mentioned conductive material) with a plating or the like around a particulate ceramic material or resin material.

  Further, the shape (form) of the conductive material may be used in the form of particles, but is not limited to the form of particles, and is a form other than the form of particles practically used as a so-called filler-based conductive resin composition such as carbon nanotube. May be.

  Examples of the carbon material include carbon fiber and c / c composite (mixture of graphite and carbon fiber) in addition to carbon black and graphite. Carbon particles such as carbon black and graphite 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 are excellent in conductivity. Also, since the carbon particles are very light, the increase in mass is minimized. 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. When carbon particles are used as conductive particles, it is possible to reduce the compatibility of the electrolyte by applying a hydrophobic treatment to the surface of the carbon, making it difficult for the electrolyte to penetrate into the pores of the current collector. is there.

  The average particle diameter of the conductive material is not particularly limited, but is preferably about 0.01 to 10 μm. In the present specification, the “particle diameter” means the maximum distance L among the distances between any two points on the contour line of the conductive material. As the value of “average particle diameter”, the average particle diameter of particles observed in several to several tens of fields using an observation means such as a scanning electron microscope (SEM) or a transmission electron microscope (TEM). The calculated value shall be adopted. Particle diameters and average particle diameters of active material particles to be described later can be defined similarly.

  In the case where the resin layer includes a conductive material, the resin forming the resin layer may include a non-conductive polymer material that binds the conductive material in addition to the upper conductive material. By using a polymer material as the constituent material of the resin layer, the binding property of the conductive material can be improved and the reliability of the battery can be improved. The polymer material is selected from materials that can withstand the applied positive electrode potential and negative electrode potential.

  Examples of polymer materials that are resins are preferably polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polyether nitrile (PEN), polyimide (PI), polyamide (PA), polytetrafluoro Ethylene (PTFE), styrene butadiene rubber (SBR), polyacrylonitrile (PAN), polymethyl acrylate (PMA), polymethyl methacrylate (PMMA), polyvinyl chloride (PVC), polyvinylidene fluoride (PVdF), epoxy resin, or These mixtures are mentioned. These materials have a very wide potential window and are stable to both positive and negative electrode potentials. In addition, since it is lightweight, it is possible to increase the output density of the battery.

  The ratio of the conductive material in the resin layer is not particularly limited, but preferably 1 to 30% by mass of the conductive material is present with respect to the total of the polymer material and the conductive material. By having a sufficient amount of the conductive material present, sufficient conductivity in the resin layer can be secured.

  Although the resistance value in the conductive resin portion of the current collector depends on the ratio of the conductive material to the resin, the volume resistivity is 1 to 10 Ωcm.

  The resin layer may contain other additives in addition to the conductive material and the resin, but preferably includes the conductive material and the resin.

  The resin layer can be manufactured by a conventionally known method. For example, it can be manufactured by using a spray method or a coating method. Specifically, there is a technique in which a slurry containing a polymer material is prepared, applied and cured. Since the specific form of the polymer material used for the preparation of the slurry is as described above, the description thereof is omitted here. Examples of other components contained in the slurry include a conductive material. Since specific examples of the conductive particles are as described above, description thereof is omitted here. Alternatively, the polymer material, conductive particles and other additives are mixed by a conventionally known mixing method, and the obtained mixture is formed into a film. Further, for example, as in the method described in JP-A-2006-190649, the resin layer may be produced by an inkjet method.

  The thickness of the current collector is not particularly limited, but it is preferably as thin as possible to increase the output density of the battery. In a bipolar secondary battery, the resin current collector that exists between the positive electrode and the negative electrode may have a high electrical resistance in the direction parallel to the stacking direction, so the thickness of the current collector can be reduced. It is. Specifically, the thickness of the current collector is preferably 0.1 to 150 μm, and more preferably 10 to 100 μm.

Tables 1 and 2 exemplify linear expansion coefficients of typical resins and conductive materials. As shown in Tables 1 and 2, the linear expansion coefficients of the polymer material and the conductive material described above have different values. For example, as shown in Table 1, resin polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET) have large linear expansion coefficients of 11 to 13 × 10 ⁻⁵ / K, whereas polyimide (PI ), Polyamideimide (PAI), and polyvinyl chloride (PVC) have a small coefficient of linear expansion. In other words, when the temperature rises, the resin portion containing a resin having a large linear expansion coefficient has a high rate of resistance increase rapidly because the percolation path is cut off. Similarly, as shown in Table 2, stainless steel and aluminum have a very large linear expansion coefficient, and titanium and graphite have a similar large coefficient, whereas carbon fiber and c / c composite have a very small linear expansion coefficient.

  Therefore, the first conductive resin portion 71 and the second conductive resin portion 72 having different temperatures when the resistance value rapidly increases can be created by appropriately combining these resins and conductive materials. The current collector 11 having these conductive resin portions can suppress the current while maintaining the battery function, and can suppress the heat generation of the battery.

  The bipolar secondary battery described above is characterized by the structure of the current collector composed of the first conductive resin portion and the second conductive resin portion. Hereinafter, other main components will be described.

(Active material layer)
[Positive electrode (positive electrode active material layer) and negative electrode (negative electrode active material layer)]
The active material layer 13 or 15 contains an active material, and further contains other additives as necessary.

The positive electrode active material layer 13 includes a positive electrode active material. As the positive electrode active material, for example, LiMn ₂ O ₄ , LiCoO ₂ , LiNiO ₂ , Li (Ni—Co—Mn) O _2, and lithium-such as those in which a part of these transition metals are substituted with other elements Examples include transition metal composite oxides, lithium-transition metal phosphate compounds, and lithium-transition metal sulfate compounds. In some cases, two or more positive electrode active materials may be used in combination. Preferably, a lithium-transition metal composite oxide is used as the positive electrode active material from the viewpoint of capacity and output characteristics. Of course, positive electrode active materials other than those described above may be used.

The negative electrode active material layer 15 includes a negative electrode active material. Examples of the negative electrode active material include carbon materials such as graphite, soft carbon, and hard carbon, lithium-transition metal composite oxides (for example, Li ₄ Ti ₅ O ₁₂ ), metal materials, lithium alloy negative electrode materials, and the like. . In some cases, two or more negative electrode active materials may be used in combination. Preferably, from the viewpoint of capacity and output characteristics, a carbon material or a lithium-transition metal composite oxide is used as the negative electrode active material. Of course, negative electrode active materials other than those described above may be used.

  The average particle diameter of each active material contained in each active material layer 13, 15 is not particularly limited, but is preferably 1 to 20 μm from the viewpoint of increasing the output.

  The positive electrode active material layer 13 and the negative electrode active material layer 15 include a binder.

  Although it does not specifically limit as a binder used for an active material layer, For example, the following materials are mentioned. Polyethylene, polypropylene, polyethylene terephthalate (PET), polyether nitrile (PEN), polyacrylonitrile, polyimide, polyamide, cellulose, carboxymethyl cellulose (CMC), ethylene-vinyl acetate copolymer, polyvinyl chloride, styrene-butadiene rubber (SBR) ), Isoprene rubber, butadiene rubber, ethylene / propylene rubber, ethylene / propylene / diene copolymer, styrene / butadiene / styrene block copolymer and hydrogenated product thereof, styrene / isoprene / styrene block copolymer and hydrogenated product thereof Thermoplastic polymers such as products, polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), tetrafluoroethylene / hexafluoropropylene copolymer (FE) ), Tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), ethylene / tetrafluoroethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), ethylene / chlorotrifluoroethylene copolymer (ECTFE) , Fluororesin such as polyvinyl fluoride (PVF), vinylidene fluoride-hexafluoropropylene-based fluororubber (VDF-HFP-based fluororubber), vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene-based fluororubber (VDF-HFP-) TFE fluorine rubber), vinylidene fluoride-pentafluoropropylene fluorine rubber (VDF-PFP fluorine rubber), vinylidene fluoride-pentafluoropropylene-tetrafluoroethylene Fluoro rubber (VDF-PFP-TFE fluoro rubber), vinylidene fluoride-perfluoromethyl vinyl ether-tetrafluoroethylene fluoro rubber (VDF-PFMVE-TFE fluoro rubber), vinylidene fluoride-chlorotrifluoroethylene fluoro rubber Examples thereof include vinylidene fluoride-based fluororubber such as (VDF-CTFE-based fluororubber), an epoxy resin, and the like. Among these, polyvinylidene fluoride, polyimide, styrene / butadiene rubber, carboxymethyl cellulose, polypropylene, polytetrafluoroethylene, polyacrylonitrile, and polyamide are more preferable. These suitable binders are excellent in heat resistance, have a very wide potential window, are stable at both the positive electrode potential and the negative electrode potential, and can be used for the active material layer. These binders may be used alone or in combination of two.

  The amount of the binder contained in the active material layer is not particularly limited as long as it is an amount capable of binding the active material, but is preferably 0.5 to 15% by mass with respect to the active material layer. Yes, more preferably 1 to 10% by mass.

  Examples of other additives that can be included in the active material layer include a conductive additive, an electrolyte salt (lithium salt), and an ion conductive polymer.

  The conductive assistant refers to an additive that is blended in order to improve the conductivity of the positive electrode active material layer or the negative electrode active material layer. Examples of the conductive assistant include carbon materials such as carbon black such as acetylene black, graphite, and vapor grown carbon fiber. When the active material layer contains a conductive additive, an electronic network inside the active material layer is effectively formed, which can contribute to improvement of the output characteristics of the battery.

Examples of the electrolyte salt (lithium salt) include Li (C ₂ F ₅ SO ₂ ) ₂ N, LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAsF ₆ , LiCF ₃ SO _{3 and the} like.

  Examples of the ion conductive polymer include polyethylene oxide (PEO) -based and polypropylene oxide (PPO) -based polymers.

  The compounding ratio of the components contained in the positive electrode active material layer and the negative electrode active material layer is not particularly limited. The mixing ratio can be adjusted by appropriately referring to known knowledge about the non-aqueous solvent secondary battery. The thickness of each active material layer is not particularly limited, and conventionally known knowledge about the battery can be appropriately referred to. For example, the thickness of each active material layer is about 2 to 100 μm.

  The resistance values in the positive electrode active material layer and the negative electrode active material layer depend on the mixing ratio of the active materials, but are, for example, 0.02 to 0.3 Ωcm, which is smaller than the resistance value of the conductive resin portion of the current collector. .

(Electrolyte layer)
As the electrolyte constituting the electrolyte layer 13, a liquid electrolyte or a polymer electrolyte can be used.

  The liquid electrolyte has a form in which a lithium salt as a supporting salt is dissolved in an organic solvent as a plasticizer. Examples of the organic solvent that can be used as the plasticizer include carbonates such as ethylene carbonate (EC) and propylene carbonate (PC). Further, as the supporting salt (lithium salt), a compound that can be added to the active material layer of the electrode, such as LiBETI, can be similarly employed.

  On the other hand, the polymer electrolyte is classified into a gel electrolyte containing an electrolytic solution and an intrinsic polymer electrolyte containing no electrolytic solution.

  The gel electrolyte has a configuration in which the above liquid electrolyte 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), and copolymers thereof. In such polyalkylene oxide polymers, electrolyte salts such as lithium salts can be well dissolved.

  In addition, when an electrolyte layer is comprised from a liquid electrolyte or a gel electrolyte, you may use a separator for an electrolyte layer. Specific examples of the separator include a microporous film made of polyolefin such as polyethylene or polypropylene.

  The intrinsic polymer electrolyte has a structure in which a supporting salt (lithium salt) is dissolved in the matrix polymer, and does not include an organic solvent that is a plasticizer. Therefore, when the electrolyte layer is composed of an intrinsic polymer electrolyte, there is no fear of liquid leakage from the battery, and the reliability of the battery can be improved.

  The matrix polymer of the gel electrolyte or the intrinsic polymer electrolyte can exhibit excellent mechanical strength by forming a crosslinked structure. In order to form a crosslinked structure, thermal polymerization, ultraviolet polymerization, radiation polymerization, electron beam polymerization, etc. are performed on a polymerizable polymer (for example, PEO or PPO) for forming a polymer electrolyte using an appropriate polymerization initiator. A polymerization treatment may be performed.

(Outermost layer current collector)
As the material of the outermost layer current collector, for example, a metal or a conductive polymer can be adopted. From the viewpoint of ease of taking out electricity, a metal material is preferably used. Specifically, metal materials, such as aluminum, nickel, iron, stainless steel, titanium, copper, are mentioned, for example. In addition to these, a clad material of nickel and aluminum, a clad material of copper and aluminum, or a plating material of a combination of these metals can be preferably used. Moreover, the foil by which aluminum is coat | covered on the metal surface may be sufficient. In addition, a PTC element (Positive Temperature Coefficient element) whose resistance rapidly increases when a predetermined temperature is exceeded may be used. Among these, aluminum and copper are preferable from the viewpoints of electron conductivity and battery operating potential.

(Tabs and leads)
A tab may be used for the purpose of taking out the current outside the battery. The tab is electrically connected to the outermost layer current collector or current collector plate, and is taken out of the laminate sheet which is a battery exterior material.

  The material which comprises a tab in particular is not restrict | limited, The well-known highly electroconductive material conventionally used as a tab for lithium ion secondary batteries can be used. As a constituent material of the tab, for example, metal materials such as aluminum, copper, titanium, nickel, stainless steel (SUS), and alloys thereof are preferable, and aluminum, copper, and the like are more preferable from the viewpoint of light weight, corrosion resistance, and high conductivity. Is preferred. Note that the same material may be used for the positive electrode tab and the negative electrode tab, or different materials may be used.

  The positive terminal lead and the negative terminal lead are also used as necessary. As the material of the positive terminal lead and the negative terminal lead, a terminal lead used in a known lithium ion secondary battery can be used. It should be noted that the part taken out from the battery outer packaging material 29 has a heat insulating property so as not to affect the product (for example, automobile parts, particularly electronic devices) by contacting with peripheral devices or wiring and causing leakage. It is preferable to coat with a heat shrinkable tube or the like.

(Battery exterior material)
As the battery exterior material 29, a known metal can case can be used, and a bag-like case using a laminate film containing aluminum that can cover a power generation element (battery element) can be used. For example, a laminate film having a three-layer structure in which PP, aluminum, and nylon are laminated in this order can be used as the laminate film, but the laminate film is not limited thereto. A laminate film is desirable from the viewpoint that it is excellent in high output and cooling performance, and can be suitably used for a battery for large equipment for EV and HEV.

(Insulation part)
The insulating part 31 prevents a liquid junction due to leakage of the electrolytic solution from the electrolyte layer 17. In addition, the insulating part 31 prevents the adjacent current collectors in the battery from coming into contact with each other or the occurrence of a short circuit due to a slight irregularity at the end of the unit cell layer 19 in the power generation element 21. Is provided.

  As a material constituting the insulating portion 31, it should have insulating properties, sealing properties against falling off of the solid electrolyte, sealing properties against moisture permeation from the outside (sealing properties), heat resistance at the battery operating temperature, and the like. That's fine. For example, urethane resin, epoxy resin, polyethylene resin, polypropylene resin, polyimide resin, rubber and the like can be used. Among these, polyethylene resin and polypropylene resin are preferably used as the constituent material of the insulating portion 31 from the viewpoints of corrosion resistance, chemical resistance, ease of production (film forming property), economy, and the like.

  In addition, said bipolar secondary battery can be manufactured by a conventionally well-known manufacturing method.

<Appearance structure of bipolar secondary battery>
FIG. 7 is a perspective view showing the appearance of a laminated flat bipolar lithium ion secondary battery which is a typical embodiment of a bipolar secondary battery. As shown in FIG. 7, the laminated flat lithium ion secondary battery 50 has a rectangular flat shape, and a positive electrode tab 58 and a negative electrode tab 59 for taking out electric power from both sides thereof. Has been pulled out. The power generation element (battery element) 57 is encased in the battery exterior material 52 of the bipolar lithium ion secondary battery 50, and the periphery thereof is heat-sealed. The power generation element (battery element) 57 includes a positive electrode tab 58 and a negative electrode. The tab 59 is sealed while being pulled out. Here, the power generation element (battery element) 57 corresponds to the power generation element (battery element) 21 of the bipolar lithium ion secondary battery 10 shown in FIG. 1 described above, and is a positive electrode (positive electrode active material layer). ) 13, a plurality of single battery layers (single cells) 19 composed of the electrolyte layer 17 and the negative electrode (negative electrode active material layer) 15 are laminated.

  The bipolar lithium ion secondary battery is not limited to a stacked flat shape, and the wound bipolar lithium ion secondary battery may be of a cylindrical shape. The cylindrical shape may be deformed into a rectangular flat shape, and is not particularly limited. In the said cylindrical shape thing, a laminate film may be used for the exterior material, and the conventional cylindrical can (metal can) may be used, for example, It does not restrict | limit. Preferably, the power generation element (battery element) is covered with an aluminum laminate film. With this configuration, weight reduction can be achieved.

  7 is not particularly limited, and the positive electrode tab 58 and the negative electrode tab 59 may be pulled out from the same side, or the positive electrode tab 58 and the negative electrode tab 59 may be pulled out. However, the present invention is not limited to the one shown in FIG. 7, for example. In addition, in a wound bipolar secondary battery, a terminal may be formed using, for example, a cylindrical can (metal can) instead of a tab.

  The above-mentioned bipolar lithium ion secondary battery is a power source for driving a vehicle or an auxiliary device that requires a high volume energy density and a high volume output density as a large capacity power source for an electric vehicle, a hybrid electric vehicle, a fuel cell vehicle, and a hybrid fuel cell vehicle. It can utilize suitably for a power supply.

<Battery assembly>
The assembled battery is formed by connecting a plurality of the bipolar secondary batteries. Specifically, at least two or more are used, and are configured by serialization, parallelization, or both. Capacitance and voltage can be freely adjusted by paralleling in series.

  FIG. 8 is an external view of a typical embodiment of the assembled battery, FIG. 8A is a plan view of the assembled battery, FIG. 8B is a front view of the assembled battery, and FIG. 8C is a side view of the assembled battery. is there. As shown in FIG. 8, the assembled battery 300 of this embodiment forms a small assembled battery 250 that can be attached / detached by connecting a plurality of bipolar secondary batteries in series or in parallel. A plurality of small assembled batteries 250 are connected in series or in parallel, and the assembled battery 300 has a large capacity and a large output suitable for a vehicle driving power source and an auxiliary power source that require high volume energy density and high volume output density. Can also be formed. 8A is a plan view of the assembled battery, FIG. 8B is a front view, and FIG. 8C is a side view. The small assembled battery 250 that can be attached / detached has an electrical connection means such as a bus bar. The assembled battery 250 is stacked in a plurality of stages using the connection jig 310. How many bipolar secondary batteries are connected to produce the assembled battery 250, and how many assembled batteries 250 are laminated to produce the assembled battery 300 depends on the vehicle (electric vehicle) to be mounted. It may be determined according to the battery capacity and output.

<Vehicle>
The vehicle of this embodiment is equipped with the bipolar secondary battery or an assembled battery formed by combining a plurality of these. Since a long-life battery excellent in long-term reliability and output characteristics can be configured, it is possible to configure a plug-in hybrid electric vehicle having a long EV mileage and an electric vehicle having a long charge mileage when such a battery is mounted. In other words, a bipolar secondary battery or an assembled battery formed by combining a plurality of these can be used as a power source for driving a vehicle. Bipolar secondary batteries or battery packs made by combining a plurality of these batteries, such as hybrid cars, fuel cell cars, and electric cars (for example, automobiles, passenger cars, trucks, buses, etc. Etc.), and motorcycles (including motorcycles and tricycles) can be used to provide a long-life and highly reliable automobile. However, the application is not limited to automobiles. For example, it can be applied to various power sources for moving vehicles such as other vehicles, for example, trains, and power sources for mounting such as uninterruptible power supplies. It is also possible to use as.

  FIG. 9 is a conceptual diagram of a vehicle equipped with an assembled battery. As shown in FIG. 9, in order to mount the assembled battery 300 on a vehicle such as the electric vehicle 400, the battery pack 300 is mounted under the seat at the center of the vehicle body of the electric vehicle 400. This is because if it is installed under the seat, the interior space and the trunk room can be widened. The place where the assembled battery 300 is mounted is not limited to the position under the seat, but may be a lower part of the rear trunk room or an engine room in front of the vehicle. The electric vehicle 400 using the assembled battery 300 as described above has high durability and can provide sufficient output even when used for a long period of time. Furthermore, it is possible to provide an electric vehicle (EV) and a hybrid vehicle (HEV) that are excellent in reduction of carbon dioxide emission for environmental protection, fuel consumption, driving performance, and the like.

  The control of the bipolar secondary battery mounted on the vehicle will be described in detail.

  As an example, control of a bipolar secondary battery mounted on a vehicle is exemplified, but the present invention can also be applied to a device using a bipolar secondary battery. Two examples of the control of the bipolar secondary battery mounted on the vehicle are listed below, but the control is not limited to these.

  The first control is a control for detecting the temperature inside the bipolar secondary battery and limiting the current taken out from the battery when the detected temperature exceeds a predetermined temperature. This predetermined temperature is a temperature at which the resistance of the first conductive resin 71 included in the current collector 11 of the bipolar secondary battery increases rapidly and interrupts the current flowing through the first conductive resin 71. At that time, a current can be passed through the second conductive resin portion 72. The second control is a control for setting a target current to be extracted from the bipolar secondary battery, and limiting the current to be extracted from the battery when the current that can be extracted from the battery is less than a certain value from the target current. When the current that can be taken out is smaller than the target current by a certain value or more, the resistance of the first conductive resin portion 71 included in the current collector 11 of the bipolar secondary battery suddenly increases, and the current does not flow easily. And control which sets a target electric current value to the electric current value of the quantity which can be sent through the 2nd conductive resin part 72 can be performed.

  Each control will be described in detail.

  First, the first control will be described in detail.

  FIG. 10 is a configuration diagram of a control device that detects the temperature of the bipolar secondary battery and performs current limiting. As shown in FIG. 10, a control device 500 that performs current limitation of the bipolar secondary battery 10 includes a battery internal temperature detection unit 501, a temperature determination unit 502, and a vehicle 400 having the bipolar secondary battery 10. Battery internal state control means 505 and vehicle control means 506 are included. Further, as shown in FIG. 10, each means transmits and receives signals in each means connected by signal wiring, and the electric current generated by charging / discharging between the bipolar secondary battery 10 and the vehicle 400 through the electric wiring is obtained. Flowing.

  The battery internal temperature detection unit 501 measures the temperature in the bipolar secondary battery, and transmits the temperature result to the temperature determination unit 502. The battery internal temperature detection means 501 is a device that can detect the internal temperature of the bipolar secondary battery 10, and for example, reads a signal from a temperature sensor installed inside the battery and transmits the temperature information. It is a device that can. The temperature determination unit 502 determines whether or not the transmitted temperature is equal to or higher than a predetermined temperature, and transmits the result of the temperature state to the battery internal state control unit 504. The temperature determination unit 502 is a general computer that can compare with a predetermined temperature input in advance and output the comparison result. The battery internal state control means 505 performs control such as adjusting the current extracted from the bipolar secondary battery 10 based on the transmitted comparison result, and transmits information related to the control to the vehicle control means 506. The vehicle control means 506 controls the vehicle 400 with the current taken out from the bipolar secondary battery 10 based on the transmitted information related to control.

  FIG. 11 is a flowchart of a method for performing current limiting by detecting the temperature of the bipolar secondary battery. As shown in FIG. 11, first, the vehicle 400 is activated, and a current can be taken out from the bipolar secondary battery 10 (step S100). Next, detection of the internal temperature of the bipolar secondary battery 10 is started by the internal battery temperature detecting means 500 so that the internal temperature can be detected (step S101). Here, the current limiting control of the bipolar secondary battery 10 is started, and the target current of the current taken out from the battery is determined (step S102). Next, extraction of current from the bipolar secondary battery 10 is started (step S103). Next, the battery internal temperature is detected, and it is determined whether or not the detected temperature is equal to or higher than a predetermined temperature (step S104). If the predetermined temperature has not been reached, step 104 is repeated. If the temperature in the battery is equal to or higher than the predetermined temperature, the target current of the current extracted from the bipolar secondary battery 10 is limited, and the current extracted with time is reduced (step S105). Then, the battery internal temperature is detected, and it is determined whether or not the detected temperature is a specific temperature (step 106). If a specific temperature has not been reached, step 105 is repeated. When the internal temperature of the battery becomes equal to or higher than a specific temperature, the control for limiting the current taken out from the bipolar secondary battery 10 is terminated (step 107).

  FIG. 12 is a relationship diagram between the current and the temperature in the battery when the current of the bipolar secondary battery is detected and the current is limited. As shown in FIG. 12, when the temperature in the battery rises and reaches a predetermined temperature, the current is limited, the target current is limited, and the current taken out with time is reduced. And it restrict | limits so that the temperature in a battery may not become more than specific temperature. As described above, when the temperature in the bipolar secondary battery 10 reaches a predetermined temperature or higher, a current flows only in the second conductive resin portion 72 included in the current collector 11, and the first conductive resin portion 71 is connected to the first conductive resin portion 71. Temperature rise due to current concentration can be prevented. Further, since the current flows only in the second conductive resin portion 72, the battery function can be maintained and the vehicle can be moved.

  Next, the second control will be described in detail.

  FIG. 13 is a configuration diagram of a control device that detects a current from the bipolar secondary battery and performs current limitation. As shown in FIG. 13, a control device 500 that limits the current of the bipolar secondary battery 10 includes, for example, a current detection unit 503, a current determination unit 504, and a battery in a vehicle 400 having the bipolar secondary battery 10. Internal state control means 504 and vehicle control means 506 are included. Further, as shown in FIG. 13, each means transmits / receives a signal in each means connected by signal wiring, and current from charging / discharging with the vehicle 400 through electric wiring from the bipolar secondary battery 10 is transmitted. Flowing. Explanation of the same means as in the first control is omitted.

  The current detection means 503 detects the actual amount of current flowing out of the bipolar current. The current detection means is, for example, a general current measuring instrument, and it is sufficient that the measured current value can be transmitted as the current determination means 504. The current determination unit 504 determines whether or not the transmitted actual current value and target current value are smaller than a predetermined current value, and transmits the determination result to the battery internal state control unit 504. The current determination unit 504 may use a general computer, and a predetermined current value may be input in advance. The battery internal state control unit 504 performs control such as adjusting the current taken out from the bipolar secondary battery 10 based on the transmitted result, and transmits information related to the control to the vehicle control unit 506.

  FIG. 14 is a flowchart of a method for performing current limiting by detecting current from a bipolar secondary battery. As shown in FIG. 14, first, the vehicle 400 is activated, and a current can be taken out from the bipolar secondary battery 10 (step S100). Next, detection of the current taken out from the bipolar secondary battery 10 is started by the current detection means 502, and the current can be detected (step S201). Here, the current limiting control of the bipolar secondary battery 10 is started, and the target current of the current taken out from the battery is determined (step S102). Next, extraction of current from the bipolar secondary battery 10 is started (step S103). Next, the actual current flowing from the battery is detected, and it is determined whether or not the detected actual current value is smaller than the target current value by a predetermined current value or more (step S204). Here, the determination may be made based on whether or not a state where the current value is smaller than a predetermined current value continues for a predetermined time. If the current value is not equal to or greater than the predetermined current value, step S204 is repeated. If the actual current value is smaller than the target current value by a predetermined current value or more, the target current of the current extracted from the bipolar secondary battery 10 is limited, and the target current value is gradually reduced to the predetermined target current value (step S205).

  FIG. 15 is a graph showing the relationship between the current and the temperature in the battery when current limiting is performed for the bipolar secondary battery. As shown in FIG. 15, when the actual current extracted from the battery is smaller than the target current value by a predetermined current value or more, the target current is limited by limiting the current, and is gradually extracted to the predetermined target current value with time. Reduce current. Then, when a predetermined target current value is reached, the state is continued. As a result, when the resistance of the first conductive resin portion 71 included in the current collector 11 in the bipolar secondary battery 10 increases and the current cannot be taken out, only the current corresponding to the second conductive resin portion 72 is obtained. Control the current to take out. By controlling the current, temperature rise due to current concentration on the first conductive resin portion 71 can be prevented. Further, since the current flows only in the second conductive resin portion 72, the battery function can be maintained and the vehicle can be moved.

  The first embodiment described above has the following effects.

  In the first embodiment, the bipolar secondary battery 10 includes a current collector 11 having a first conductive resin portion 71 and a second conductive resin portion 72 that have different temperatures when the resistance value rapidly increases. Even if the temperature in the battery rises, current can be passed through the second conductive resin portion. Therefore, current can be prevented from flowing through the first conductive resin portion having high resistance, so that heat generation at the current collector can be suppressed and heat generation of the battery can be suppressed. That is, when the temperature rises to a predetermined temperature, the resistance value of the first conductive resin portion 71 rapidly increases, and even if the percolation path is cut off and the current is cut off, the resistance value of the second conductive resin portion 72 remains unchanged and the percolation path is cut off. Since there is no current, it can flow.

  In addition, the bipolar secondary battery 10 including the current collector 11 having the first conductive resin portion 71 and the second conductive resin portion 72 that have different temperatures when the resistance value rapidly increases is capable of supplying current even when the temperature exceeds a predetermined temperature. It can be taken out while being suppressed, and temperature rise can be suppressed while maintaining the battery function. A plurality of such bipolar secondary batteries can be connected in series and / or in parallel to form an assembled battery. Furthermore, such a bipolar secondary battery or an assembled battery can be mounted on a vehicle as a motor power source. Then, when the current from the bipolar secondary battery or the temperature inside the battery is detected and the resistance of the first conductive resin portion 71 increases rapidly, the current is limited, and the current is concentrated on the first conductive resin portion 71. Temperature rise can be prevented. When the current is limited, the battery function can be maintained because the current flows only in the second conductive resin portion 72, and the vehicle can be moved.

(Second Embodiment)
FIG. 16 is a schematic view schematically showing the current collector of the second embodiment. Since the configuration of the entire bipolar secondary battery is the same as that of the first embodiment, only the current collector different from that of the first embodiment will be described below. As shown in FIG. 16, in the current collector 11 of the second embodiment, the first conductive material is continuously provided between the positive electrode and the negative electrode in the direction (thickness direction) in which the electrodes of the bipolar secondary battery are stacked. A resin portion 71 and a second conductive resin portion are formed. 16A, the second conductive resin portion 72 has a cylindrical shape, and FIG. 16B has a quadrangular prism shape. In FIG. 16A, the first conductive resin portion 71 may be continuously formed in a cylindrical shape. As described above, the first conductive resin portion 71 and the second conductive resin portion 72 are continuously formed between the electrodes, whereby heat generation in the battery can be suppressed.

  FIG. 17 is a schematic diagram schematically showing how the current flows in the second embodiment. As shown in FIG. 17A, the first conductive resin portion 71 and the second conductive resin portion 72 are continuously formed between the positive electrode active material layer 13 and the negative electrode active material layer 15. Preferably, the first conductive resin portion 71 is formed so as to be in contact with the positive electrode active material layer 13 and the negative electrode active material layer 15 and penetrate through the second conductive resin portion 72 in the thickness direction.

  When the temperature reaches a predetermined temperature, the resistance of the first conductive resin portion 71 increases, so that the current flows around the positive electrode active material layer 13 and flows into the second conductive resin portion 72 as shown in FIG. 17A. However, as shown in FIG. 17B, when the first conductive resin portion 71 is not continuously formed between the positive electrode active material layer 13 and the negative electrode active material layer 15, that is, in the positive electrode active material layer 13, the first conductive resin portion 71 is not formed. When the part 71 is not in contact, the current flows around the second conductive resin part 72 so as to avoid the first conductive resin part 71.

  Here, when the resistance values of the second conductive resin portion 72 and the positive electrode active material layer 13 are compared, the positive electrode active material layer 13 is smaller. Therefore, when it becomes difficult to flow through the first conductive resin portion 71 where the current reaches a predetermined temperature and the resistance is increased, the current flows in the surface direction of the second conductive resin portion 72 as shown in FIG. 17B as shown in FIG. 17A. The amount of heat generated is smaller when the positive electrode active material layer 13 is passed through.

  The second embodiment has the following effects in addition to the effects of the first embodiment. Since the first conductive resin portion 71 and the second conductive resin portion are continuously formed between the positive electrode and the negative electrode, the temperature inside the battery rises to a predetermined temperature, and current does not easily flow to the first conductive resin portion 71. At this time, since the current flowing in the first conductive resin portion 71 flows in the second conductive resin portion 72, the direction of the current flows in the positive electrode active material layer 13. Therefore, the amount of generated heat can be reduced and the temperature rise of the battery can be suppressed as compared with the case where current flows in the surface direction of the second conductive resin portion 72.

(Third embodiment)
The current collector 11 of the third embodiment is characterized by the configuration of the first conductive resin portion 71 and the second conductive resin portion 72, and the structure is the same as that of the first example as shown in FIG. Similar forms can be taken. In the current collector 11 of the third embodiment, the mixing amount of the conductive material 71b constituting the first conductive resin portion 71 is smaller than the mixing amount of the conductive material 72b constituting the second conductive resin portion 72. The first conductive resin portion 71 with a small amount of conductive material can prevent a current from flowing when the temperature inside the battery rises to a predetermined temperature. On the other hand, the second conductive resin portion 72 with a large amount of conductive material is less likely to break the percolation path and does not have a large change in resistance, so that a current can flow.

  The third embodiment has the following effects in addition to the effects of the first embodiment. By providing the conductive resin portions with different amounts of mixed conductive materials, the percolation path can be adjusted according to the amount of conductive material, and the current suppression effect can be increased. Furthermore, the temperature rise of the battery can be controlled.

(Fourth embodiment)
The current collector 11 of the fourth embodiment is characterized by the configuration of the first conductive resin portion 71 and the second conductive resin portion 72, and the structure is the same as that of the first example as shown in FIG. Similar forms can be taken. In the current collector 11 of the fourth embodiment, the mixed amount of the conductive material 71b constituting the first conductive resin portion 71 is smaller than the mixed amount of the conductive material 72b constituting the second conductive resin portion 72, and further the conductive material The linear expansion coefficient of the material 71b is smaller than the linear expansion coefficient of the conductive material 72b. The first conductive resin portion 71 made of a conductive material having a small mixing amount and a small linear expansion coefficient can prevent a current from flowing when the temperature inside the battery rises to a predetermined temperature. On the other hand, the second conductive resin portion 72 made of a conductive material having a large amount of mixing and a large linear expansion coefficient is less likely to have a percolation path and has a large resistance change, so that a current can flow.

  The fourth embodiment has the following effects in addition to the effects of the third embodiment. By providing the conductive resin portions in which the mixed amount of the conductive material and the linear expansion coefficient of the conductive material are different, the percolation path can be adjusted by the amount and expansion of the conductive material, and the current suppression effect can be further increased. Furthermore, the temperature rise of the battery can be controlled.

(Fifth embodiment)
The current collector 11 of the fifth embodiment is characterized by the configuration of the first conductive resin portion 71 and the second conductive resin portion 72, and the structure is the same as that of the first example as shown in FIG. Similar forms can be taken. In the current collector 11 of the fifth embodiment, the linear expansion coefficient of the resin 71 a constituting the first conductive resin portion 71 is larger than the linear expansion coefficient of the resin 72 a constituting the second conductive resin portion 72. The first conductive resin portion 71 having a large resin linear expansion coefficient can prevent a current from flowing when the temperature inside the battery rises to a predetermined temperature. On the other hand, the second conductive resin portion 72 having a small coefficient of linear expansion of the conductive material is less likely to break the percolation path and does not have a large resistance change, so that a current can flow.

  The fifth embodiment has the following effects in addition to the effects of the first embodiment. By providing the conductive resin portions having different linear expansion coefficients of the resins, the percolation path can be adjusted by the expansion of the resin, and the current suppression effect can be increased. Furthermore, the temperature rise of the battery can be controlled.

(Sixth embodiment)
The current collector 11 of the sixth embodiment is characterized by the configuration of the first conductive resin portion 71 and the second conductive resin portion 72, and the structure thereof is the same as that of the first example as shown in FIG. Similar forms can be taken. In the current collector 11 of the sixth embodiment, the linear expansion coefficient of the resin 71a constituting the first conductive resin portion 71 is larger than the linear expansion coefficient of the resin 72b constituting the second conductive resin portion 72. The mixing amount of the material 71b is smaller than the mixing amount of the conductive material 72b. The first conductive resin portion 71 composed of a resin having a large linear expansion coefficient and a conductive material having a small mixing amount can prevent a current from flowing when the temperature inside the battery rises to a predetermined temperature. On the other hand, the second conductive resin portion 72 composed of a resin having a small linear expansion coefficient and a conductive material having a large amount of mixing is hard to break a percolation path, and since a large resistance change is yes, a current can flow.

  The sixth embodiment has the following effects in addition to the effects of the fifth embodiment. By providing the conductive resin portions in which the linear expansion coefficient of the resin and the mixing amount of the conductive material are different, the percolation path can be adjusted by the amount of the conductive material and the expansion of the resin, and the current suppressing effect can be further increased. Furthermore, the temperature rise of the battery can be controlled.

(Seventh embodiment)
FIG. 18 is a schematic view schematically showing the current collector of the seventh embodiment. As shown in FIG. 18, the current collector 11 of the seventh embodiment penetrates in the direction in which the electrodes (not shown) of the bipolar secondary battery are stacked, and further, the second conductive resin portion 72 It is installed outside the one conductive resin portion 71. 18A, the second conductive resin portion 72 is provided outside the first conductive resin portion having a cylindrical shape, and FIG. 18B is the second conductive resin portion 72 provided outside the second conductive resin portion having a quadrangular prism shape. . As described above, the first conductive resin portion 71 may have any shape, and the second conductive resin portion 72 is installed outside the first conductive resin portion 71, that is, on the outer peripheral portion of the current collector 11. Just do it. Since the temperature inside the battery rises to a predetermined temperature and no current flows in the first conductive resin portion 71 and current flows in the second conductive resin portion 72, the current flows in the outer peripheral portion of the current collector 11.

  The seventh embodiment has the following effects in addition to the effects of the first embodiment. When the temperature inside the battery rises above a predetermined temperature, a current flows through the second conductive resin portion 72 provided on the outer peripheral portion of the current collector, so that heat dissipation generated by the current flowing can be promoted. it can. And the temperature rise of a battery can also be controlled.

(Eighth embodiment)
FIG. 19 is a schematic view schematically showing the current collector of the eighth embodiment. When the solubility parameter of the adjacent conductive resin is within 2, the first conductive resin portion 71 and the second conductive resin portion 72 included in the current collector 11 are stably connected. However, as shown in FIG. 19, in the case of two or more, the first conductive resin portion 71 and the second conductive resin portion 72 are phase-separated and a clearance c is formed.

  The eighth embodiment has the following effects in addition to the effects of the first embodiment. By providing a plurality of conductive resin portions having a resin solubility parameter within two, phase separation of adjacent conductive resins can be prevented, current suppression effect can be further increased, and battery temperature rise Can also be controlled.

(Ninth embodiment)
The current collector 11 of the ninth embodiment is characterized by the configuration of the first conductive resin portion 71 and the second conductive resin portion 72, and the structure is the same as that of the first example as shown in FIG. Similar forms can be taken. In the current collector 11 of the ninth embodiment, the linear expansion coefficient of the resin 71a constituting the first conductive resin portion 71 is larger than the linear expansion coefficient of the conductive material 71b. In such a first conductive resin portion 71, when the temperature inside the battery rises to a predetermined temperature, the resin expands more than the conductive material, the percolation path is easily cut off, and current can be prevented from flowing. .

  The ninth embodiment provides the following effects in addition to the effects of the first embodiment. By providing a conductive resin portion having a resin linear expansion coefficient larger than that of the conductive material, the percolation path can be adjusted by expanding the resin larger than the conductive material, and the current suppression effect can be further increased. Furthermore, the temperature rise of the battery can be controlled.

10, 50 Bipolar secondary battery (bipolar lithium ion secondary battery),
11 Current collector,
13 Positive active material layer,
15 negative active material layer,
17 electrolyte layer,
19 cell layer,
21 power generation elements,
23 Bipolar electrode,
25 positive current collector,
27, 57 negative electrode current collector,
29 Laminated film,
31 Sealing part (insulating part),
58 positive electrode tab,
59 Negative electrode tab,
71 first conductive resin part,
71a first resin,
71b first conductive material,
72 second conductive resin portion,
72a second resin,
72b second conductive material,
250 small battery pack,
300 battery packs,
310 connection jig,
400 electric car,
500 controller,
501 battery internal temperature detection means,
502 temperature determination means,
503 current detection means;
504 current determination means,
505 battery internal state control means,
506 Vehicle control means.

Claims (14)

A current collector for a bipolar secondary battery in which a first electrode is provided on a first surface and a second electrode having a polarity different from that of the first electrode is provided on a second surface opposite to the first surface;
The current collector includes a first conductive resin portion that increases in electrical resistance when the temperature rises and reaches a predetermined temperature, and an increase in electrical resistance when the temperature rises to the predetermined temperature. A second conductive resin portion less than the portion,
Each of the first conductive resin portion and the second conductive resin portion is disposed so as to continuously extend from a surface facing the first electrode to a surface facing the second electrode. Current collector for the next battery. The first conductive resin portion and the second conductive resin portion are arranged between the first electrode and the second electrode so as to be aligned in a direction orthogonal to the thickness direction. A current collector for a bipolar secondary battery described in 1. The first conductive resin portion is configured by mixing a first conductive material with a first resin,
The second conductive resin portion is configured by mixing a second conductive material with a second resin,
The current collector for a bipolar secondary battery according to claim 1 or 2 , wherein the mixing amount of the second conductive material is larger than the mixing amount of the first conductive material. 4. The current collector for a bipolar secondary battery according to claim 3 , wherein a linear expansion coefficient of the second conductive material is larger than a linear expansion coefficient of the first conductive material. 5. The first conductive resin portion is configured by mixing a first conductive material with a first resin,
The second conductive resin portion is configured by mixing a second conductive material with a second resin,
The current collector for a bipolar secondary battery according to claim 1 or 2 , wherein the linear expansion coefficient of the second resin is smaller than the linear expansion coefficient of the first resin. The current collector for a bipolar secondary battery according to claim 5 , wherein the mixing amount of the second conductive material is larger than the mixing amount of the first conductive material. The bipolar type according to any one of claims 1 to 6 , wherein the second conductive resin portion is disposed outside the first conductive resin portion in a direction orthogonal to a thickness direction. Current collector for secondary battery. The bipolar secondary according to any one of claims 1 to 7 , wherein the solubility parameter of the first conductive resin portion and the solubility parameter of the second conductive resin portion are not separated by two or more. Current collector for batteries. The current collector for a bipolar secondary battery according to any one of claims 1 to 8 , wherein the linear expansion coefficient of the first resin is larger than the linear expansion coefficient of the first conductive material. . A current collector for a bipolar secondary battery according to any one of claims 1 to 9 , a plurality of the first electrode, the second electrode, and a separator including an electrolyte layer are stacked. A bipolar secondary battery comprising:
The bipolar secondary battery, wherein the separator is interposed between the first electrode and the second electrode. A control device for a bipolar secondary battery for controlling the bipolar secondary battery according to claim 10 ,
Battery internal temperature measuring means for measuring the temperature inside the bipolar secondary battery;
Temperature determining means for determining whether the temperature inside the bipolar secondary battery is equal to or higher than the predetermined temperature;
Battery internal state control means for limiting a current taken out from the bipolar secondary battery when the temperature inside the bipolar secondary battery is determined to be equal to or higher than the predetermined temperature. Secondary battery control device. A control device for a bipolar secondary battery for controlling the bipolar secondary battery according to claim 10 ,
A battery internal current measuring means for measuring an actual current value taken out from the bipolar secondary battery;
Current value determination means for determining whether or not the actual current value is equal to or greater than a predetermined current value;
A control apparatus for a bipolar secondary battery, comprising: battery internal state control means for limiting a current taken out from the bipolar secondary battery when the actual current value is determined to be equal to or greater than a predetermined current value. . A bipolar secondary battery control method for controlling the bipolar secondary battery according to claim 10 , comprising:
A battery internal temperature measurement step for measuring the temperature inside the bipolar secondary battery;
A temperature determination step of determining whether the temperature inside the bipolar secondary battery is equal to or higher than the predetermined temperature;
A battery internal state control step of limiting a current taken out from the bipolar secondary battery when the temperature inside the bipolar secondary battery is determined to be equal to or higher than the predetermined temperature. Secondary battery control method. A bipolar secondary battery control method for controlling the bipolar secondary battery according to claim 10 , comprising:
A battery internal current measuring step for measuring an actual current value taken out from the bipolar secondary battery;
A current value determination step of determining whether or not the actual current value is equal to or greater than a predetermined current value;
A control method for a bipolar secondary battery, comprising: a battery internal state control step for limiting a current taken out from the bipolar secondary battery when the actual current value is determined to be equal to or greater than a predetermined current value. .