JP4622294B2 - Bipolar battery, bipolar battery manufacturing method, assembled battery, and vehicle equipped with the same - Google Patents

Description

  The present invention relates to a bipolar battery, a method for manufacturing a bipolar battery, an assembled battery, and a vehicle on which these are mounted.

  In recent years, reduction of carbon dioxide emissions has been strongly desired for environmental protection. In the automobile industry, there are high expectations for reducing carbon dioxide emissions by introducing electric vehicles (EVs) and hybrid electric vehicles (HEVs), and we are eager to develop secondary batteries for motor drives that hold the key to their practical application. Has been done. As a secondary battery, attention is focused on a stacked lithium ion secondary battery that can achieve a high energy density and a high output density.

  In a lithium ion secondary battery, sheet-like electrodes are electrically connected in series in an enclosed battery package with an electrolyte layer in between, and current flows in the stacking direction of the electrodes, that is, in the thickness direction of the battery. The area of the energization path is wide and high output can be obtained.

  When a lithium ion secondary battery is charged for the first time after being assembled, a reaction occurs inside the battery, and a lot of gases such as hydrogen, hydrocarbons, and carbon oxides are generated. If such a gas is left inside the battery, the battery swells or the internal pressure of the battery increases, which may affect the laminated structure and cause a decrease in battery characteristics.

  The gas is generated in large quantities during the first charge and is hardly generated during subsequent use. Therefore, a manufacturing method is proposed in which after charging once, the gas is exhausted from the battery package, transferred to another process line, and hermetically sealed again with a resin film or the like (see, for example, Patent Document 1). .

On the other hand, a bipolar battery is configured by stacking a plurality of electrolytes sandwiched between bipolar electrodes. The electrolyte can be a solid electrolyte, but can also be used by impregnating a separator with a liquid electrolyte or a gel electrolyte. When a liquid or gel electrolyte is used for the electrolyte, if the electrolyte moves freely, a liquid junction (short circuit) occurs in the bipolar battery, so the cell unit is covered with an insulator and sealed ( For example, see Patent Document 2).
JP-A-10-199561 JP-A-11-204136

  However, even in a bipolar battery, if it is a lithium ion secondary battery, gas is generated during the first charge as described above. The generated gas accumulates in the interior covered with the insulator. As described above, in order to exhaust the gas from the package after the battery is assembled and charged once as described above, it is necessary to remove the insulator around the unit cell. When the insulator is peeled off, the electrolyte flows out and a liquid junction occurs.

  Thus, in the case of a bipolar battery using a liquid or gel electrolyte as the electrolyte, there is a problem that the gas generated during the first charge cannot be treated well.

  The present invention has been made in view of the above problems, and a bipolar battery capable of easily treating internal gas, a method of manufacturing the bipolar battery, an assembled battery in which a plurality of bipolar batteries are connected, and the secondary battery or the assembled battery An object is to provide a vehicle equipped with a vehicle.

(1) The bipolar battery of the present invention is formed by laminating 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 with an electrolyte interposed therebetween. A seal member disposed between the current collectors so as to surround a single battery layer that is a bipolar battery and includes the adjacent positive electrode active material layer, electrolyte, and negative electrode active material layer When the pulled out from the interior enclosed by the seal member to the outside, has a bag-shaped tab opening and towards the internal, the tab and other of said tabs being drawn from another hierarchy, the In the stacking direction of the unit cells, the bag-like portions are drawn out so as not to overlap.
(1) 'In the bipolar battery of the present invention, the bipolar electrode in which the positive electrode active material layer is formed on one surface of the current collector and the negative electrode active material layer is formed on the other surface is 90% by weight or less of the electrolyte. A bipolar battery that is laminated with a gel polymer electrolyte in between so as to surround a single battery layer that includes the adjacent positive electrode active material layer, the electrolyte, and the negative electrode active material layer, A bipolar battery comprising: a seal member disposed between the current collectors; and a bag-like tab that is drawn out from an inside surrounded by the seal member and opens toward the inside.

(2) The bipolar battery manufacturing method of the present invention includes a step of forming a plurality of bipolar electrodes by providing a positive electrode active material layer on one surface of a current collector and providing a negative electrode active material layer on the other surface, At the edge of the current collector of the bipolar electrode, a sealing member and a bag-like tab opening toward the inside surrounded by the sealing member, and the bag-like portions of tabs adjacent to each other are stacked on each other. A step of arranging without gaps so as not to overlap in a direction, a step of stacking a separator holding an electrolyte on the one bipolar electrode, and so that the separator is sandwiched between the positive electrode active material layer and the negative electrode active material layer, Laminating another bipolar electrode on the separator, performing a first charge on the stacked bipolar battery, and, after the first charge, drilling a hole in the tab and passing through the tab. , And a step of discharging the gas inside surrounded by the sealing member.
(2) 'The method for manufacturing a bipolar battery of the present invention includes a step of forming a plurality of bipolar electrodes by providing a positive electrode active material layer on one surface of a current collector and providing a negative electrode active material layer on the other surface; A step of arranging a sealing member and a bag-like tab opening toward the inside surrounded by the sealing member on the edge of the current collector of the bipolar electrode without gaps, and an electrolyte containing 90% by weight or less of an electrolyte solution Laminating a separator to be held on the one bipolar electrode, and laminating another bipolar electrode on the separator so that the separator is sandwiched between the positive electrode active material layer and the negative electrode active material layer. A step of performing an initial charge on the bipolar battery configured as described above, and a step of opening a hole in the tab and discharging an internal gas surrounded by the seal member through the tab after the initial charge. Method of manufacturing a bipolar battery that.

  (3) The assembled battery of the present invention is formed by connecting a plurality of bipolar batteries manufactured by the bipolar battery of (1) or the bipolar battery manufacturing method of (2).

  (4) The vehicle according to the present invention is mounted with the bipolar battery of (1) or the bipolar battery manufactured by the manufacturing method of the bipolar battery of (2) or the assembled battery of (3) as a driving power source. Become.

  According to the bipolar battery of the above (1), the bag-shaped tab is drawn out from the inside surrounded by the seal member, and the tab opens toward the inside, so that occurs when the bipolar battery is charged for the first time. Gas that accumulates in the tub. Here, if a hole is made in the tab, the internal gas can be easily discharged. Further, since the tab surrounds the periphery of the unit cell layer together with the seal member, leakage of the electrolyte can be prevented, and as a result, a short circuit can be prevented. In addition, the sealing member and the tab can prevent moisture from entering from the outside of the battery and can improve the rigidity of the battery.

  According to the bipolar battery manufacturing method of (2) above, since the sealing member and the bag-like tab opening toward the inside surrounded by the sealing member are arranged without a gap, when the bipolar battery is first charged Gas generated in the tub accumulates in the tub. Here, if a hole is made in the tab, the internal gas can be easily discharged. Further, since the tab surrounds the periphery of the unit cell layer together with the seal member, leakage of the electrolyte can be prevented, and as a result, a short circuit can be prevented. In addition, the sealing member and the tab can prevent moisture from entering from the outside of the battery and can improve the rigidity of the battery.

  According to the assembled battery of the above (3), it is possible to obtain a high capacity and high output by connecting a plurality of bipolar batteries, and the reliability of each bipolar battery is high. Can be improved.

  According to the vehicle of the above (4), for a compact vehicle having various characteristics such as the bipolar battery of the above (1), the bipolar battery manufactured by the above (2), or the assembled battery of the above (3). Can provide power.

  Embodiments of the present invention will be described below with reference to the drawings. In the following drawings, each component is exaggerated for clarity of explanation.

(First embodiment)
The bipolar battery according to the present invention is a bipolar battery in which 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 is laminated with an electrolyte interposed therebetween. A sealing member disposed between the current collectors so as to surround a single battery layer including the adjacent positive electrode active material layer, the electrolyte, and the negative electrode active material layer; A bag-like tab that is drawn out from the inside surrounded by the seal member and opens toward the inside. The bipolar battery of this embodiment is a lithium ion secondary battery.

  1 is a plan view of a bipolar battery to which the present invention is applied, FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1, and FIG. 3 is a cross-sectional view taken along line 3-3 of FIG.

  In the bipolar battery 10 of the present invention, the positive electrode terminal plate 11a and the negative electrode terminal plate 11b extend laterally, and in addition, the gas venting tab 20 also extends laterally. The positive terminal plate 11a and the negative terminal plate 11b extend in contact with the outermost current collector of the bipolar battery 10, respectively.

  The tab 20 is laminated | stacked for every hierarchy, as shown in FIG. 2 and FIG. Each part of the bipolar battery 10 will be described with reference to FIGS.

  In the bipolar battery 10, as shown in FIG. 2, a positive electrode active material layer 13 and a negative electrode active material layer 14 are formed at the center of both surfaces of one current collector 12 other than both ends. A single battery layer 16 is formed by sandwiching an electrolyte layer 15 between the active material layer 13 and the negative electrode active material layer 14, and a plurality of single battery layers 16 are stacked. A current collector (referred to as an end current collector 17) at both ends is connected to the above-described positive electrode terminal plate 11a and negative electrode terminal plate 11b.

  A configuration in which the positive electrode active material layer 13 and the negative electrode active material layer 14 are provided with the current collector 12 interposed therebetween is called a bipolar electrode.

  Here, the electrolyte layer 15 is, for example, a liquid electrolyte or gel electrolyte held in a polymer skeleton. As the electrolyte layer 15, it is preferable to hold a gel electrolyte. The gel electrolyte includes an electrolyte containing about several to 98% by weight, and in this embodiment, a gel electrolyte containing 70% by weight or more is used.

  In this bipolar battery 10, in order to prevent electrolyte leakage from the unit cell layer 16, the periphery of each unit cell layer 16 is surrounded, and between the current collectors 12, or between the current collectors 12 and the end current collectors. A seal member 19 is provided between the bodies 17.

  The seal member 19 is a double-sided tape in which an adhesive is applied to both sides of a base material. The base material is formed of an insulating resin such as polypropylene (PP), polyethylene (PE), or polyamide synthetic fiber. The pressure-sensitive adhesive is formed of a solvent-resistant material such as synthetic rubber, butyl rubber, synthetic resin, or acrylic. By using such a material for the seal member 19, liquid leakage from the single cell layer 16 can be prevented, and a short circuit due to contact between the current collectors can be prevented.

  As shown in FIGS. 2 and 3, the seal member 19 is only partially replaced with the tab 20. The tab 20 includes a bag portion 21 and a porous body 22.

  The bag part 21 is formed from insulating materials, such as resin. The bag portion 21 is drawn out from the range surrounded by the seal member 19 and opens toward the inside surrounded by the seal member 19. That is, it opens toward the single cell layer 16. As with the seal member 19, the bag portion 21 is coated with adhesive on the upper and lower sides and fixed to the upper and lower current collectors 12 (17). Thereby, the bag part 21 seals the unit cell layer 16 together with the seal member 19.

  The porous body 22 is disposed in the bag portion 21. The porous body 22 has a plurality of holes formed inside and outside, and hardly allows liquid to pass but allows gas to pass. The porous body 22 is formed of, for example, a nonwoven fabric in which fibers are entangled or a woven fabric. If a nonwoven fabric or a woven fabric is used for the porous body 22, the porosity of the porous body 22 can be easily adjusted. The porous body 22 may be formed of a porous resin such as polyethylene, polypropylene, polytetrafluoroethylene, polyester, polyamide, polyimide, silicon, primer, or urethane, for example.

  Next, the manufacturing procedure of the bipolar battery 10 of the present invention will be described.

  FIG. 4 is a view for explaining the manufacturing procedure of the bipolar battery of the present invention.

  As a manufacturing procedure of the bipolar battery 10 of the present invention, as shown in FIG. 4, first, an electrode layer (positive electrode active material layer 13 or negative electrode active material layer 14, for example, positive electrode active material layer) is formed on the end current collector 17. 13) is laminated, and an electrolyte layer 15 is further laminated thereon.

  Then, the seal member 19 is disposed on the edge of the end current collector 17. Here, the center of the seal member 19 is greatly opened so as to cover only the edge of the end current collector 17. Further, the tab 20 is also arranged at the edge of the end current collector 17 so as to be pulled out from a part of the seal member 19. Here, the tab 20 is disposed so as to open toward the inside of the battery.

  When the sealing member 19 and the tab 20 are thus laminated, the sealing member 19 and the tab 20 surround the electrolyte layer 15. Here, since the adhesive is applied to both sides of the seal member 19 and the tab 20, the seal member 19 and the tab 20 are bonded to each other when they are stacked on the current collector 17.

  In addition, the thickness of the sealing member 19 and the tab 20 is thicker than the thickness of the positive electrode active material layer 13 and the electrolyte layer 15. The thickness of the sealing member 19 and the tab 20 is the total thickness of the positive electrode active material layer 13, the electrolyte layer 15, and the negative electrode active material layer 14 to be stacked later, that is, ± 30 μm of the thickness of the unit cell layer 16. It is desirable to be within. By adjusting the thickness of the sealing member 19 and the tab 20 to the total thickness of the unit cell layer 16, it is possible to prevent the current collectors 12 and 17 from being distorted with an increase in the number of stacked layers, and to reduce the reactivity and short circuit due to the distortion. Can be prevented.

  The end current collector 17, the positive electrode active material layer 13, the electrolyte layer 15, and the seal member 19 that are stacked as described above are referred to as a single cell 25. The single cell 26 located in the middle of the bipolar battery 10 is provided with electrode layers on both sides of the current collector 12, for example, a positive electrode active material layer 13 on the upper surface and a negative electrode active material layer 14 on the lower surface. Say. That is, a structure in which an electrolyte layer 15 is stacked on a bipolar electrode formed by stacking a negative electrode active material layer 14, a current collector 12, and a positive electrode active material layer 13, and a seal member 19 is stacked on the edge of the current collector 12. This is cell 26. By increasing the number of stacked single cells 26, the bipolar battery 10 can have a desired number of stacked layers.

  The single cell 27 stacked at the end of the bipolar battery 10 is different from the single cell 25 stacked at the beginning described above in that the end current collector 17 is stacked on the negative electrode active material layer 14.

  In this way, a plurality of single cells are manufactured in advance with the single cells 25 to 27 as one unit, and the bipolar battery 10 is stacked in a necessary number. A state of stacking the single cells 25 to 27 will be described.

  The middle unit cell 26 is stacked on the first unit cell 25. By repeating this, the number of stacked single cells 26 on the single cell 25 is increased. When the single cell 26 is laminated on the single cell 25, the adhesive of the sealing member 19 and the tab 20 of the single cell 25 is bonded to the lower surface of the current collector 12 of the single cell 26. Similarly, when another unit cell 26 is stacked on the unit cell 26, the adhesive of the lower unit cell 26 is adhered to the lower surface of the current collector 12 of the upper unit cell 26. As described above, the sealing member 19 and the tab 20 are bonded to the current collector 12 every time the single cells 26 are stacked, and the electrolyte layer 15 is sealed. Thereby, the liquid leakage from the electrolyte layer 15 can be prevented.

  Finally, the single cell 27 is stacked, and the current collector 17 of the single cell 27 is bonded to the seal member 19 and the tab 20 of the single cell 26, whereby the bipolar battery 10 is completed.

  The operation of the bipolar battery 10 will be described.

  FIG. 5 is an enlarged view of the tab 20.

  In the bipolar battery 10 of the present invention, a tab 20 is disposed together with a seal member 19 so as to seal each unit cell layer 16. In this state, when the bipolar battery 10 is charged for the first time, a lot of gases such as hydrogen, hydrocarbons, and carbon oxides are generated. The gas fills the inside sealed by the seal member 19 and the tab 20.

  Here, an operator or the like makes a hole 23 in a part of the tab 20 as shown in FIG. Then, the gas accumulated inside passes through the fine holes of the porous body 22 of the tab 20 and is discharged to the outside. After the gas is discharged, the hole 23 is closed with an insulating material such as resin.

  As described above, the bipolar battery 10 of the present invention is provided with the tab 20. Thereby, once the bipolar battery 10 is assembled and charged to generate gas, the gas in the bipolar battery 10 can be easily discharged via the tab 20. That is, the gas can be discharged through the porous body 22 in the tab 20 by opening the initially sealed tab 20 after charging and making it communicate with the outside. Gas does not accumulate in the bipolar battery 10. As a result, it is possible to prevent a situation in which the laminated structure is affected by the increase in the battery internal pressure and the battery characteristics are deteriorated.

  Further, the tab 20 is provided with a porous body 22 therein. Therefore, the gas which is a gas is easily discharged outside. On the other hand, since the liquid electrolyte or gel electrolyte of the electrolyte layer 15 does not easily pass through the porous body 22, when the hole 23 is opened in the tab 20, the electrolyte leaks and no liquid junction occurs.

  In particular, if a porous resin such as nonwoven fabric, woven fabric, polyethylene, polypropylene, polytetrafluoroethylene, polyester, polyamide, polyimide, silicon, primer or urethane is used for the porous body 22, it is difficult to become familiar with the electrolyte. Can be more reliably prevented. If it is a nonwoven fabric or a woven fabric, the porosity of the porous body 22 can be easily adjusted, and the processing of the porous body 22 can be simplified.

  Further, the tab 20 can prevent moisture from entering from the outside of the bipolar battery 10 and can improve the strength of the bipolar battery itself.

  Further, since the bipolar battery 10 of the present invention is formed by stacking the single cells 25 to 27, when the single cell is manufactured, it is manufactured in large quantities without considering the number of stacked bipolar batteries 10, and individual bipolar batteries It is sufficient to prepare the single cells 25 to 27 necessary for manufacturing 10. Therefore, since it can be divided into two stages, that is, the production of a single cell and the production of the bipolar battery 10, it is possible to flexibly cope with a change in the number of stacks due to a design change, and in addition, the work time can be shortened. it can.

  In the above embodiment, the porous body 22 is disposed in the bag portion 21 of the tab 20. However, the porous body 22 can be omitted. If only the bag portion 21 is used, gas is accumulated in the bag portion 21 due to the generation of gas during the first charge. Here, the internal gas can be easily discharged by opening the hole 23 in the tab 20. However, it is necessary to devise such as increasing the length of the tab 20 or opening the hole 23 with the tab 20 raised so that the electrolyte does not leak.

  Moreover, although the said embodiment demonstrated the case where the tab 20 was pulled out from one place of the sealing member 19, it is not limited to this.

  FIG. 6 is a diagram illustrating a state in which a bipolar battery is drawn from a plurality of locations.

  For example, as shown in FIGS. 6A to 6C, the tab 20 can be pulled out from two to four locations. By increasing the number of tabs 20, the gas can be discharged more easily.

  In order to prevent external impact and environmental degradation, the bipolar battery has a battery stack as a whole including the template that is the body of the bipolar battery in order to prevent external impact and environmental degradation during use. May be accommodated in a battery exterior material.

  FIG. 7 is an external view in the case where a bipolar battery is configured as a battery by a battery outer packaging material.

  In the battery 30 shown in FIG. 7, the above-described positive electrode and negative electrode terminal plates are provided on the end current collector 17 of the bipolar battery 10, and leads are further attached to form electrodes 31 and 32.

  From the viewpoint of weight reduction, conventionally known battery exteriors such as polymer-metal composite laminate sheets and aluminum laminate packs in which metals (including alloys) such as aluminum, stainless steel, nickel, and copper are coated with an insulator such as polypropylene film It is preferable that the bipolar battery 10 is housed and sealed by joining a part or the whole of the peripheral part by heat fusion using a material. It is preferable to use a polymer-metal composite laminate sheet or an aluminum laminate pack having excellent thermal conductivity in that heat can be efficiently transferred from the heat source of the automobile and the inside of the battery can be quickly heated to the battery operating temperature.

  The configuration of the bipolar battery 10 is not particularly limited as long as a known material used for a general lithium ion secondary battery may be used. Hereinafter, a current collector, a positive electrode active material layer, a negative electrode active material layer, a gel electrolyte, and the like that can be used in the bipolar battery 10 will be described for reference.

[Current collector]
The current collector has a surface material of aluminum. When the surface material is aluminum, an active material layer having high mechanical strength is obtained even when the formed active material layer contains a solid polymer electrolyte. If the surface material of the current collector is aluminum, the structure thereof is not particularly limited. The current collector may be aluminum itself. In addition, the surface of the current collector may be covered with aluminum. That is, a current collector in which aluminum is coated on the surface of a substance other than aluminum (such as copper, titanium, nickel, SUS, or an alloy thereof) may be used. In some cases, a current collector in which two or more plates are bonded together may be used. From the viewpoint of corrosion resistance, ease of production, economy, and the like, it is preferable to use an aluminum foil alone as a current collector. Although the thickness of a collector is not specifically limited, Usually, it is about 10-100 micrometers.

[Positive electrode active material layer]
The positive electrode active material layer includes a positive electrode active material and a solid polymer electrolyte. In addition to this, a supporting salt (lithium salt) for increasing ionic conductivity, a conductive auxiliary agent for increasing electronic conductivity, NMP (N-methyl-2-pyrrolidone) as a solvent for adjusting slurry viscosity, a polymerization initiator AIBN (azobisisobutyronitrile) and the like may be included.

As the positive electrode active material, a composite oxide of lithium and a transition metal, which is also used in a solution-type lithium ion battery, can be used. Specifically, Li · Co-based composite oxide such as LiCoO _2, Li · Ni-based composite oxide such as LiNiO _2, Li · Mn-based composite oxide such as spinel LiMn ₂ O _4, Li · such LiFeO ₂ Examples thereof include Fe-based composite oxides. 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. By using a lithium-transition metal composite oxide as the positive electrode active material layer active material, the reactivity and cycle durability of the stacked battery can be improved and the cost can be reduced.

  In order to reduce the electrode resistance of the bipolar battery, the positive electrode active material may have a particle size smaller than that generally used in a solution type lithium ion battery in which the electrolyte is not solid. Specifically, the average particle diameter of the positive electrode active material is preferably 0.1 to 5 μm.

The solid polymer electrolyte is not particularly limited as long as it is a polymer having ion conductivity. Examples of the polymer having ion conductivity include polyethylene oxide (PEO), polypropylene oxide (PPO), and copolymers thereof. Such polyalkylene oxide polymers can well dissolve lithium salts such as LiBF ₄ , LiPF ₆ , LiN (SO ₂ CF ₃ ) ₂ , and LiN (SO ₂ C ₂ F ₅ ) ₂ . Moreover, excellent mechanical strength is exhibited by forming a crosslinked structure. In the present invention, the solid polymer electrolyte is contained in at least one of the positive electrode active material layer and the negative electrode active material layer. However, in order to further improve the battery characteristics of the bipolar battery, it is preferable to be included in both.

As the supporting salt, Li (C ₂ F ₅ SO ₂ ) ₂ N, LiBF ₄ , LiPF ₆ , LiN (SO ₂ C ₂ F ₅ ) ₂ , or a mixture thereof can be used. However, it is not necessarily limited to these.

  Examples of the conductive assistant include acetylene black, carbon black, and graphite. However, it is not necessarily limited to these.

  The amount of the positive electrode active material, solid polymer electrolyte, lithium salt, and conductive additive in the positive electrode active material layer should be determined in consideration of the intended use of the battery (output priority, energy priority, etc.) and ion conductivity. is there. For example, if the amount of the solid polymer electrolyte in the active material layer is too small, the ionic conduction resistance and the ionic diffusion resistance in the active material layer will increase, and the battery performance will deteriorate. On the other hand, if the amount of the solid polymer electrolyte in the active material layer is too large, the energy density of the battery is lowered. Therefore, in consideration of these factors, the solid polymer electrolytic mass meeting the purpose is determined.

Here, the case where a bipolar battery giving priority to battery reactivity is manufactured using a solid polymer electrolyte (ionic conductivity: 10 ⁻⁵ to 10 ⁻⁴ S / cm) at the current level will be specifically considered. In order to obtain a bipolar battery having such characteristics, the electron conduction resistance between the active material particles is kept low by increasing the conductive auxiliary agent or reducing the bulk density of the active material. At the same time, the gap is increased, and the gap is filled with a solid polymer electrolyte. The ratio of the solid polymer electrolyte may be increased by such treatment.

  The thickness of the positive electrode active material layer is not particularly limited, and should be determined in consideration of the intended use of the battery (such as emphasis on output and energy) and ion conductivity, as described for the blending amount. The thickness of a general positive electrode active material layer is about 5 to 500 μm.

[Negative electrode active material layer]
The negative electrode active material layer includes a negative electrode active material and a solid polymer electrolyte. In addition to this, a supporting salt (lithium salt) for increasing ionic conductivity, a conductive auxiliary agent for increasing electronic conductivity, NMP (N-methyl-2-pyrrolidone) as a solvent for adjusting slurry viscosity, a polymerization initiator AIBN (azobisisobutyronitrile) and the like may be included. Except for the type of the negative electrode active material, the contents are basically the same as those described in the section “Positive electrode active material”, and thus the description thereof is omitted here.

  As the negative electrode active material, a negative electrode active material that is also used in a solution-type lithium ion battery can be used. However, since the solid polymer electrolyte is used in the bipolar battery of the present invention, a composite oxide of carbon or lithium and a metal oxide or metal is preferable in consideration of the reactivity with the solid polymer electrolyte. More preferably, the negative electrode active material is a composite oxide of carbon or lithium and a transition metal. More preferably, the transition metal is titanium. That is, the negative electrode active material is more preferably titanium oxide or a composite oxide of titanium and lithium.

  By using a composite oxide of carbon or lithium and a transition metal as the negative electrode active material layer active material, the reactivity and cycle durability of the stacked battery can be improved and the cost can be reduced.

[Electrolyte layer]
The material is not limited as long as it is a layer composed of a polymer having ion conductivity and exhibits ion conductivity. It is preferable to use a solid electrolyte for preventing liquid leakage. Examples of the solid electrolyte include known solid polymer electrolytes such as polyethylene oxide (PEO), polypropylene oxide (PPO), and copolymers thereof. The solid polymer electrolyte layer contains a supporting salt (lithium salt) in order to ensure ionic conductivity. As the supporting salt, LiBF ₄ , LiPF ₆ , LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ C ₂ F ₅ ) ₂ , or a mixture thereof can be used. However, it is not necessarily limited to these. A polyalkylene oxide polymer such as PEO and PPO can dissolve lithium salts such as LiBF ₄ , LiPF ₆ , LiN (SO ₂ CF ₃ ) ₂ , and LiN (SO ₂ C ₂ F ₅ ) ₂ well. Moreover, excellent mechanical strength is exhibited by forming a crosslinked structure.

  The polymer gel electrolyte generally refers to an electrolyte solution held in an all-solid polymer electrolyte having ion conductivity. In the present application, a polymer electrolyte having a similar electrolyte solution held in a polymer skeleton having no lithium ion conductivity is also included in the polymer gel electrolyte. The type of electrolyte solution (electrolyte salt and plasticizer) used is not particularly limited.

  When the electrolyte layer is made of a polymer gel electrolyte, the electrolyte layer is formed by impregnating a separator such as a nonwoven fabric with a polymer gel raw material solution and then polymerizing using the above-described various methods. It may be. By using the separator, the filling amount of the electrolytic solution can be increased, and the thermal conductivity inside the battery is ensured.

[Laminate sheet]
The laminate sheet is used as a battery exterior material. In general, a polymer metal composite film in which a heat-fusible resin film, a metal foil, and a resin film having rigidity are laminated in this order is used.

  As the heat-fusible resin, for example, polyethylene (PE), polypropylene (PP), modified polyethylene, modified polypropylene, ionomer, ethylene vinyl acetate (EVA) and the like can be used. As the metal foil, for example, Al foil or Ni foil can be used. As the resin having rigidity, polyamide synthetic fibers such as polyester such as polyethylene terephthalate (PET) and polyamide (nylon (registered trademark)) can be used. Specifically, PE / Al foil / PET laminated film laminated from the sealing surface side toward the outer surface; PE / Al foil / nylon (registered trademark) laminated film; Ionomer / Ni foil / PET laminated film; EVA / Al foil / PET laminated film; ionomer / Al foil / PET laminated film and the like can be used. The heat-fusible resin film acts as a seal layer when the battery element is housed inside. A metal foil or a rigid resin film imparts moisture, breathability, and chemical resistance to the exterior material. The laminate sheet can be easily and reliably bonded using heat sealing such as heat sealing, impulse sealing, ultrasonic welding, and high-frequency welding.

(Second Embodiment)
In the first embodiment, the tab 20 drawn from each layer overlaps the stacking direction of the unit cell layers 16. However, in the second embodiment, the tabs in each layer are drawn so as not to overlap with other tabs drawn from other layers in the stacking direction.

  FIG. 8 is a plan view showing the bipolar battery of the second embodiment, and FIG. 9 is a cross-sectional view taken along line 9-9 of FIG. In addition, the same reference number is attached | subjected to the structure similar to 1st Embodiment, and the description is abbreviate | omitted.

  As shown in FIG. 8, in the second embodiment, in the bipolar battery 40, the positive electrode terminal plate 11a and the negative electrode terminal plate 11b extend sideways, and in addition, the venting tab 50 extends sideways. Yes.

  The tab 50 is smaller in width than the tab 20 of the first embodiment. The tab 50 includes a bag portion 51 and a porous body 52. Regarding the structure other than the size, the bag 51 is the same as the bag 21 of the first embodiment, and the porous body 52 is the same as the porous body 22 of the first embodiment.

  As shown in FIG. 9, the tabs 50 are arranged while being displaced at substantially equal intervals in the width direction of the bipolar battery 40. Thus, by shifting the tab 50, the tab 50 is not arranged at the same position when viewed in the stacking direction.

  Therefore, in order to discharge the gas from the bipolar battery 40 by charging once, even if the electrolyte leaks from the tab 50 by opening a hole in the tab 50, the electrolytes of the respective layers do not come into contact with each other. Tangle can be prevented.

  By adopting the configuration as in the second embodiment, even when a highly fluid gel electrolyte or liquid electrolyte having an electrolytic solution ratio of 95% or more is used, there is no fear of a short circuit, and gas can be easily discharged.

  As shown in FIGS. 8 and 9, the tab 50 is not only drawn from one side of the bipolar battery 40, but can also be drawn from the other side as shown in FIGS. 10 (A) to (C). it can. FIG. 10 is a diagram illustrating a state in which the tab is pulled out from a plurality of side surfaces, and (A) to (C) are diagrams illustrating modifications. As shown in FIG. 10, by pulling out the tab from a plurality of side surfaces, the range in which gas can be discharged in each layer is widened, and degassing can be performed more easily.

(Third embodiment)
In the first embodiment, a part of the seal member 19 is cut out and the tab 20 is pulled out. On the other hand, in the third embodiment, the seal member itself is caused to act similarly to the tab 20 described above.

  FIG. 11 is a view showing a state where a seal member is attached, FIG. 12 is a perspective view showing a state where a bipolar battery is produced, and FIG. 13 is a view showing a state where a through hole is formed in the seal member. The same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In the third embodiment, as shown in FIG. 11, a normal seal member 19 is arranged on the edge of the current collector 12, and a seal member 60 larger than the seal member 19 is further arranged. For example, as shown in FIG. 11, the seal member 19 is disposed on three sides of the current collector 12, and the seal member 60 is disposed on the remaining side.

  The sealing member 60 is not a mere sheet shape, and is formed, for example, by sandwiching a porous body 62 between two resin sheets. The porous body 62 has the same structure as the porous body 22 of the first embodiment. The porous body 62 is formed in a quadrangular shape, and one side is exposed from the seal member 60. The seal member 60 is disposed on the current collector 12 so that the side where the porous body 62 is exposed faces the electrolyte layer 15 side.

  The state of creating the bipolar battery according to the third embodiment is as shown in FIG.

  As shown in FIG. 12, the seal member 19 and the seal member 60 are disposed on the end current collector 17, and the electrolyte layer 15 is disposed on the positive electrode active material layer 13. On top of this, a bipolar electrode prepared in advance is laminated, and the seal member 19 and the seal member 60 are also arranged on the edge of the current collector 12 of the bipolar electrode, and the electrolyte layer 15 is further laminated. This is repeated, and finally, the end collector 17 is laminated. The positive electrode terminal plate 11a and the negative electrode terminal plate 11b are respectively attached to the lowermost and uppermost end collectors 17 to complete the bipolar battery 70 as shown in FIG.

  The bipolar battery 70 is first charged, and then a through hole 71 is opened as shown in FIG. The through hole 71 penetrates the porous body 62 of the seal member 60 of each level. Accordingly, the gas is discharged from the through hole 71 through the porous body 62.

  As described above, as in the third embodiment, the porous member 62 is included in the sealing member 60 to provide the function of a degassing tab, so that the degassing function can be obtained simply by stretching the sealing member 60. . Easy to assemble.

(Fourth embodiment)
In 3rd Embodiment, the porous body 52 is arrange | positioned in the sealing member 60, and the sealing member 60 itself has a function of a degassing tab. The porous body 52 is widely arranged in the seal member 60. In 4th Embodiment, the porous body is arrange | positioned in a sealing member so that the width | variety of the porous body arrange | positioned in a sealing member may be made small, and it may not overlap with the porous body of another hierarchy in a lamination direction. .

  FIG. 14 and FIG. 15 are views showing how the seal member is attached, and FIG. 16 is a view showing how the through hole is opened in the seal member. The same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In the fourth embodiment, as shown in FIGS. 14A to 14C and FIGS. 15D and 15E, a normal seal member 19 is disposed on the edge of the current collector 12, and the seal is further sealed. A seal member 80 larger than the member 19 is disposed.

  As shown in FIG. 14A, the positive electrode terminal plate 11a is attached to the current collector 12, the seal member 19 is disposed on the three sides of the current collector 12, and the seal member 80 is bonded to the remaining one side. Here, a porous body 82 is embedded in a part of the seal member 80. One side of the porous body 82 is exposed from the seal member 80. The seal member 80 is disposed on the current collector 12 so that the side where the porous body 82 is exposed faces the current collector 12.

  Further, the electrolyte layer 15 is overlaid on the positive electrode active material layer 13 on the current collector 12. Thereafter, a bipolar electrode is laminated on the electrolyte layer 15, and as shown in FIG. 14B, seal members 19 are disposed on three sides of the current collector 12 of the bipolar electrode. Then, the seal member 80 is bonded onto the remaining side of the current collector 12. Here, the porous body 82 embedded in the seal member 80 does not overlap with the lower layer seal member 80 (FIG. 14A) in the stacking direction.

  Similarly, as shown in FIGS. 14C, 15D, and 15E, the bipolar electrode, the seal member 19, the seal member 80, and the electrolyte layer 15 are repeatedly laminated. None of the porous bodies 82 in the seal members 80 at each level overlap in the stacking direction. That is, finally, as shown by a one-dot chain line in 15 (E), when viewed through the seal member 80 from the planar direction, the porous bodies 82 are arranged to be aligned. Finally, the negative electrode terminal plate 11b is attached to the uppermost current collector 12, and the bipolar battery 90 as shown in FIG. 16 is completed.

  The bipolar battery 90 is first charged, and then a through hole 81 is opened as shown in FIG. The through hole 81 penetrates the sealing member 80 of each layer and penetrates the porous body 82. Therefore, the gas is discharged from the through hole 81 through the porous body 82. Further, as described above, in the fourth embodiment, since the porous body 82 is arranged so as not to overlap in the stacking direction, the single porous body 82 is penetrated by one through hole 81. Only. Accordingly, when the through hole 81 is formed and the gas is discharged, the electrolyte does not leak and does not come into contact with the upper and lower layers of the electrolyte. A liquid junction can be prevented.

  As described above, as in the fourth embodiment, by including the porous body 82 in the seal member 80 and having the function of a degassing tab, the degassing function can be obtained simply by stretching the seal member 80. . Easy to assemble.

  Furthermore, since the position of the porous body 82 in the seal member 80 of each layer is different, even if the electrolyte leaks out, it does not come into contact with the electrolyte of other layers and short-circuit.

(Example)
Next, examples in which the bipolar battery was actually manufactured and evaluated will be described.

<Sample preparation>
As an example, bipolar batteries 10 and 40 corresponding to the first embodiment and the second embodiment were prepared. The common structure of the created bipolar battery is as follows.

  The current collector 12 uses a stainless (SUS) foil having a thickness of 20 μm, and the end current collector 17 is formed with one of the positive electrode active material layer 13 or the negative electrode active material layer 14, and the other current collector 12. A positive electrode active material layer 13 and a negative electrode active material layer 14 were formed.

The positive electrode active material layer 13 is composed of LiMn ₂ O ₄ (85% by weight), acetylene black (5% by weight) as a conductive auxiliary agent, polyvinylidene fluoride (PVDF) (10% by weight) as a binder, and N— as a viscosity adjusting solvent. An appropriate amount of methyl-2-pyrrolidone (NMP) is mixed to prepare a positive electrode slurry, which is applied as a positive electrode active material to one surface of a stainless steel foil (thickness 20 μm) as a current collector and dried to a film thickness of 40 μm. Positive electrode active material layer 13.

  The negative electrode active material layer 14 is prepared by mixing hard carbon (90 wt%) with PVDF (10 wt%) as a binder and NMP (appropriate amount) as a viscosity adjusting solvent to prepare a negative electrode slurry. The material layer 13 is applied to the opposite surface of the coated stainless steel foil and dried to form a negative electrode active material layer 14 having a thickness of 40 μm.

  The electrolyte layer 15 is made of a polypropylene (PP) mysterious cloth having a thickness of 50 μm, a monomer solution (copolymer of polyethylene oxide and polypropylene oxide) having an average molecular weight of 7500 to 9000 which is a precursor of an ion conductive polymer matrix, 10 weight. %, 90% by weight of 1.0 mol / l LiBETI dissolved in ethylene carbonate (EC) + dimethyl carbonate (DMC) in a mixing ratio of 1: 3 as an electrolytic solution, and a pregel solution comprising a polymerization initiator (BDK) The gel polymer electrolyte layer was obtained by sandwiching the precursor and cross-linking the precursor by irradiating the quartz glass substrate with ultraviolet rays for 15 minutes.

<Example 1>
A positive electrode active material layer 13 and an electrolyte layer 15 were laminated on the end current collector 17. A three-layer film having a width of 10 mm and a thickness of 70 μm in which nylon (registered trademark) is sandwiched between polypropylene is arranged as a sealing member 19 on three sides around the electrolyte layer 15. A tab 20 formed by sandwiching a polyamide non-woven fabric (porous body 22) from above and below by a polypropylene film (bag portion 21) was disposed on the other side. Thereafter, a bipolar electrode was laminated on the electrolyte layer 15, and the seal member 19 and the tab 20 were similarly arranged on the four sides.

  The same process was repeated until five cell layers 16 were formed. The bipolar battery 10 was completed by welding the seal member 19 and the tab 20 with heat and pressure from above and below, and sealing each layer.

<Example 2>
A positive electrode active material layer 13 and an electrolyte layer 15 were laminated on the end current collector 17. A three-layer film having a width of 10 mm and a thickness of 70 μm in which nylon (registered trademark) is sandwiched between polypropylene is arranged as a sealing member 19 on three sides around the electrolyte layer 15. A tab 50 formed by sandwiching a polyamide non-woven fabric (porous body 52) from above and below by a polypropylene film (bag portion 51) was disposed on the other side. Thereafter, a bipolar electrode was laminated on the electrolyte layer 15, and the seal member 19 was similarly arranged on three sides. The tabs 50 were arranged on the remaining one side so as not to overlap with the lower tab 50 in the stacking direction.

The same process was repeated until five cell layers 16 were formed. The bipolar member 40 was completed by welding the sealing member 19 and the tab 50 with heat and pressure from above and below, and sealing each layer.
< Reference Example , Example 4>
Further, in the same manufacturing process as the bipolar batteries 10 and 40 of Example 1 and Example 2 described above, only the content of the electrolyte solution in the gel electrolyte layer 15 was changed, and the bipolar batteries of the reference example and Example 4 were made. Created.

The electrolyte layer 15 of < Reference Example > and <Example 4> is prepared by adding a monomer solution (polyester) having an average molecular weight of 7500 to 9000 which is a precursor of an ion conductive polymer matrix to a 50 μm thick polypropylene (PP) unknown cloth. 2% by weight of a copolymer of ethylene oxide and polypropylene oxide), 98% by weight of 1.0 mol / l LiBETI dissolved in ethylene carbonate (EC) + dimethyl carbonate (DMC) in a mixing ratio of 1: 3 as an electrolytic solution, And a pregel solution comprising a polymerization initiator (BDK) was permeated, sandwiched between quartz glass substrates and irradiated with ultraviolet rays for 15 minutes to crosslink the precursor, thereby obtaining a gel polymer electrolyte layer.

<Comparative example>
Further, as a comparative example of this evaluation, a laminate was formed by arranging substantially the same configuration as in Example 1 above, without arranging the tabs 20 and 50, and instead arranging a seal member. This laminate was vacuum-sealed with a laminate pack, and the tabs for measuring the voltage of each layer were exposed to the outside to form a bipolar battery.

<Evaluation 1>
First, each of the bipolar batteries of Examples 1 and 2 and Comparative Example 1 was initially charged. The charging current was a constant current and constant voltage (CCCV) charging of 0.1 C for 15 hours on the capacity basis estimated from the coating weight of the positive electrode. Thereafter, in Examples 1 and 2, holes were formed in the gas venting tabs 20 and 50, gas was extracted from each layer, and vacuum-sealed using an aluminum laminate sheath as it was. Since the bipolar battery of Comparative Example 1 was not provided with a degassing tab, it was left in a state where the internal gas accumulated.

  Thereafter, these bipolar batteries were charged with a constant current (CC) at a current of 1 C, then discharged with a constant current (CC), and this was regarded as one cycle, and this cycle was performed at 60 ° C. for 100 cycles (cycle test).

  When the discharge capacity after 100 cycles (capacity maintenance ratio [%]) was measured with the initial discharge capacity as 100%, it was as shown in FIG.

  FIG. 17 is a diagram showing the results of the cycle test.

  As shown in FIG. 17, in the bipolar battery of Example 1, the discharge capacity was almost 96% even after the 100th charge / discharge cycle. Also for the bipolar battery of Example 2, the discharge capacity was 95% and hardly decreased even after 100 cycles.

  On the other hand, in the bipolar battery of the comparative example, the discharge capacity was 74%, which was lower than the bipolar batteries of Examples 1 and 2.

  The appearance of the bipolar battery hardly changed in Examples 1 and 2, but in Comparative Example 1, gas bubbles were observed in the electrode portion due to the generation of gas.

  From the above results, it was found that the capacity deterioration due to gas generation is less when the gas vent tab is installed in each layer and the gas is vented after the initial charge.

<Evaluation 2>
First, the first charge was performed for each of the bipolar batteries of Examples 3 and 4. The charge current was a constant current and constant voltage (CCCV) charge of 0.1 C for 15 hours on a capacity basis estimated from the coating weight of the positive electrode. Thereafter, holes were made in the gas venting tabs 20 and 50, gas was extracted from each layer, and vacuum-sealed using an aluminum laminate exterior as it was.

  In Example 3, the electrolyte oozes out in the degassing tab 20, and when a hole for degassing was made, the electrolyte solution of each layer contacted and became a liquid junction. However, in Example 4, the degassing part was shifted and the liquid was not in contact with each other even if a hole was made for degassing, so that each layer was not in a liquid junction state.

  Thereafter, the battery was charged with a constant current (CC) at a current of 1 C, then discharged with a constant current (CC), and this was regarded as one cycle, and this cycle was performed at 60 ° C. for 100 cycles.

  When the initial discharge capacity was 100% and the discharge capacity after 100 cycles (capacity maintenance ratio [%]) was measured, the results shown in FIG. 17 were obtained.

  It has been found that the present invention can also be applied to an electrolyte having a relatively high ratio of electrolytic solution and an extremely high fluidity if the tab 50 is shifted as in the bipolar battery of Example 4.

  In the case where the ratio of the electrolytic solution is not so high, the present invention can be applied without shifting the tab 20 as shown in the first embodiment. That is, when the content rate of the electrolyte solution of the electrolyte layer 15 is high, it turned out that the structure of Example 4 (2) is more preferable than the structure of Example 3 (1).

(Fifth embodiment)
In the fifth embodiment, an assembled battery is configured by connecting a plurality of the bipolar batteries 10, 40, 70, 90 of the first to fourth embodiments in parallel and / or in series.

  FIG. 18 is a perspective view of an assembled battery according to the fifth embodiment, and FIG. 19 is a view of the internal configuration as viewed from above.

  As shown in FIGS. 18 and 19, the assembled battery 100 includes a plurality of batteries (see FIG. 7) 30 in which the bipolar batteries 10, 40, 70, 90 according to the first to fourth embodiments described above are packaged by a laminate pack. Are connected. Between the batteries 30, the electrodes 31 and 32 of each battery are connected by a conductive bar 103. In this assembled battery 100, electrode terminals 101 and 102 are provided on one side as electrodes.

  In this assembled battery 100, ultrasonic welding, heat welding, laser welding, rivet, caulking, electron beam, or the like can be used as a connection method when a plurality of batteries 30 are connected. By adopting such a connection method, the assembled battery 100 with long-term reliability can be manufactured.

  According to the assembled battery 100, it is possible to obtain high capacity and high output by forming an assembled battery using the bipolar batteries 10, 40, 70, 90 according to the first to fourth embodiments described above, And since the reliability of each battery is high, the long-term reliability as an assembled battery can be improved.

  The bipolar batteries 10, 40, 70, 90 as the assembled battery may all be connected in parallel, or a plurality of bipolar batteries 10, 40, 70, 90 may be connected in series. Further, a series connection and a parallel connection may be combined.

(Sixth embodiment)
In the sixth embodiment, the vehicle is configured by mounting the bipolar batteries 10, 40, 70, 90 of the first to fourth embodiments or the assembled battery 100 of the fifth embodiment as a driving power source. The vehicle using the bipolar batteries 10, 40, 70, 90 or the assembled battery as a motor power source is an automobile whose wheels are driven by a motor, such as an electric vehicle or a hybrid vehicle.

  For reference, FIG. 20 shows a schematic diagram of an automobile 110 on which the assembled battery 100 is mounted. The assembled battery 100 mounted on the automobile has the characteristics described above. For this reason, the automobile on which the assembled battery 100 is mounted has high durability, and can provide sufficient output even after being used for a long period of time.

It is a top view of the bipolar battery to which this invention is applied. FIG. 2 is a cross-sectional view taken along line 2-2 in FIG. FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 1. It is a figure for demonstrating the manufacturing procedure of the bipolar battery of this invention. It is an enlarged view of a tab. It is a figure which shows a mode that several places of the bipolar battery are pulled out. It is an external view at the time of comprising a bipolar battery as a battery with a battery exterior material. It is a top view which shows the bipolar battery of 2nd Embodiment. FIG. 9 is a cross-sectional view taken along line 9-9 in FIG. It is a figure which shows a mode that the tab was pulled out from the several side surface, (A)-(C) is a figure which shows a modification, respectively. It is a figure which shows a mode that a sealing member is attached. It is a perspective view which shows a mode that a bipolar battery is created. It is a figure which shows a mode that a through-hole is opened in a sealing member. It is a figure which shows a mode that a sealing member is attached. It is a figure which shows a mode that a sealing member is attached. It is a figure which shows a mode that a through-hole is opened in a sealing member. It is a figure which shows the result of a cycle test. It is a perspective view of the assembled battery which concerns on 5th Embodiment. It is drawing which looked at the internal structure from the upper part. It is the schematic of the motor vehicle carrying an assembled battery.

Explanation of symbols

10, 40, 70, 90 ... bipolar battery,
11a ... positive terminal plate,
11b ... negative electrode terminal plate,
12, 17 ... current collector,
13 ... positive electrode active material layer,
14 ... negative electrode active material layer,
15 ... Gel electrolyte layer,
16 ... cell layer,
19 ... Sealing member,
20, 50 ... tabs,
21, 51 ... bag part,
22, 52, 62, 82 ... porous body,
30 ... Battery,
60, 80 ... sealing member,
80 ... tab,
100 ... assembled battery,
110: Car.

Claims (11)

A bipolar battery 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 is a bipolar battery laminated with an electrolyte interposed therebetween,
A sealing member disposed between the current collectors so as to surround the periphery of the unit cell layer including the adjacent positive electrode active material layer, the electrolyte, and the negative electrode active material layer;
A bag-like tab that is drawn out from the inside surrounded by the sealing member and opens toward the inside;
Have
The bipolar battery with which the said tab is pulled out so that the bag-shaped part may not overlap with the said other tab pulled out from the other hierarchy in the lamination direction of the said cell. 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 is laminated with a gel polymer electrolyte containing 90% by weight or less of an electrolytic solution in between. A bipolar battery,
A sealing member disposed between the current collectors so as to surround the periphery of the unit cell layer including the adjacent positive electrode active material layer, the electrolyte, and the negative electrode active material layer;
A bag-like tab that is drawn out from the inside surrounded by the sealing member and opens toward the inside;
Bipolar battery having   The bipolar battery according to claim 1, wherein the tab has a porous body disposed inside a bag.   The bipolar battery according to claim 3, wherein the porous body is a nonwoven fabric in which fibers are entangled or a woven fabric.   The bipolar battery according to claim 3, wherein the porous body is made of polyethylene, polypropylene, polytetrafluoroethylene, polyester, polyamide, polyimide, silicon, primer, or urethane. The porous body is sandwiched in the seal member and exposed only toward the inner side surrounded by the seal member,
The bipolar battery according to any one of claims 3 to 5, wherein a part of the seal member plays a role of a tab that wraps the porous body. The said tab is pulled out so that it may not overlap with the said other tab pulled out from the other hierarchy in the lamination direction of the said cell. The bipolar battery described in 1. The positive electrode active material layer includes a composite oxide of lithium and a transition metal,
The bipolar battery according to any one of claims 1 to 7 , wherein the negative electrode active material layer includes a composite oxide of carbon or lithium and a transition metal. Forming a positive electrode active material layer on one side of the current collector and providing a negative electrode active material layer on the other side to form a plurality of bipolar electrodes;
One edge of the current collector of the bipolar electrode is provided with a seal member and a bag-like tab opening toward the inside surrounded by the seal member, and the bag-like portions of the tabs in the other layers are connected to each other. A step of arranging without gaps so as not to overlap in the battery stacking direction;
Stacking a separator holding an electrolyte on the one bipolar electrode;
Laminating another bipolar electrode on the separator such that the separator is sandwiched between the positive electrode active material layer and the negative electrode active material layer;
First charging a stacked bipolar battery; and
After the first charge, the step of opening a hole in the tab, and exhausting the gas surrounded by the seal member through the tab;
A method of manufacturing a bipolar battery having Forming a positive electrode active material layer on one side of the current collector and providing a negative electrode active material layer on the other side to form a plurality of bipolar electrodes;
A step of arranging a seal member and a bag-like tab opening toward the inside surrounded by the seal member without any gap at the edge of the current collector of the one bipolar electrode;
Stacking a separator holding a gel polymer electrolyte containing 90% by weight or less of an electrolytic solution on the one bipolar electrode;
Laminating another bipolar electrode on the separator such that the separator is sandwiched between the positive electrode active material layer and the negative electrode active material layer;
First charging a stacked bipolar battery; and
After the first charge, the step of opening a hole in the tab, and exhausting the gas surrounded by the seal member through the tab;
A method of manufacturing a bipolar battery having Clogging the hole opened in the tab with resin;
Covering and sealing the bipolar battery with a laminate sheet;
The method of manufacturing a bipolar battery according to claim 9 or 10 , further comprising: