JP2006147534A - Bipolar battery, battery pack and vehicle loaded with them - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bipolar battery and a battery pack capable of uniformly taking out a current by suppressing variation of a current density distribution even if the same material of a current collector of a bipolar electrode is used for a current collector of an end pole, and to provide a vehicle loaded with them. <P>SOLUTION: The bipolar battery is provided with a positive electrode tab 51 electrically connected with the current collector 21 of the positive electrode end pole 33 of a battery element 30 and a negative electrode tab 52 electrically connected with the current collector of the negative electrode end pole 34 of the battery element. The positive electrode tab is at least larger than a projected area of a positive electrode active material layer 22 of the positive electrode end pole and arranged on the current collector to cover the projected surface of positive electrode active material layer. The negative electrode tab is at least larger than the projected area of the negative electrode active material layer 24 of the negative electrode end pole and arranged on the current collector to cover the projected surface of the negative electrode active material layer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a bipolar battery, an assembled battery formed by electrically connecting a plurality of the bipolar batteries, and a vehicle equipped with these batteries.

  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 bipolar battery that can achieve high energy density and high output density (see Patent Document 1).

  The bipolar battery includes a battery element in which a plurality of bipolar electrodes are connected in series with an electrolyte layer interposed therebetween. In the bipolar electrode, a positive electrode is formed by providing a positive electrode active material layer on one surface of a current collector, and a negative electrode is formed by providing a negative electrode active material layer on the other surface. In a bipolar battery, current flows in the direction in which the bipolar electrodes are stacked (hereinafter referred to as the “stacking direction”) in the battery element, so the current path is short, the current loss is small, and the current collector is made ultrathin. You can also.

Patent Document 1 describes that stainless steel is used as the material of the current collector. From the viewpoint of weight reduction, it has been proposed to use aluminum for the current collector of the terminal electrode located at the terminal in the stacking direction.
JP 2001-236946 A (paragraphs 0019, 0021)

  Stainless steel is stable to both positive and negative electrode active materials and has excellent performance that can be used for both positive and negative electrode current collectors, but compared to copper and aluminum. Low conductivity.

  Here, since the current path is short along the bipolar electrode stacking direction and the current collector is a thin film, no significant problem arises even if the current conductivity of the current collector is slightly low. However, since the electrons must be collected at the terminal at the terminal pole, the structure is along the direction orthogonal to the stacking direction, that is, the direction in which the current collector of the terminal electrode extends (hereinafter referred to as “planar direction”). Current flow is required. Thus, when the current is taken out, the current flows in the plane direction, so that a large problem arises if the conductivity of the current collector at the terminal electrode is low. For example, the current density around the portion from which current is extracted becomes higher than that in other portions, and the resistance increases. As a result of promoting the deterioration caused by the variation in the current density distribution, there is a possibility that the battery does not react normally.

  As described in Patent Document 1, when aluminum is used for the current collector of the terminal electrode, the above-described problem in taking out the current does not occur. On the other hand, since a different material from the current collector of the bipolar electrode is used for the current collector of the terminal electrode, variation occurs between the active material layer in the terminal electrode and the active material layer in the bipolar electrode, and the bipolar Battery performance will be reduced.

  The present invention has been made in order to solve the problems associated with the above-described prior art, and even if the same material as the current collector of the bipolar electrode is used for the current collector of the terminal electrode, the variation in the current density distribution is suppressed. It is an object of the present invention to provide a bipolar battery, an assembled battery, and a vehicle equipped with these, which can take out current uniformly.

The present invention according to claim 1, which achieves the above object, comprises connecting a plurality of bipolar electrodes in which a positive electrode is formed on one surface of a current collector and a negative electrode is formed on the other surface through an electrolyte layer. In a bipolar battery in which the battery element is housed in an outer case,
A positive electrode tab electrically connected to a current collector of a positive electrode terminal electrode of the battery element;
A negative electrode tab electrically connected to the current collector of the negative electrode terminal electrode of the battery element,
The positive electrode tab has a size larger than at least the projected area of the positive electrode active material layer of the positive electrode terminal electrode, and is disposed on the current collector so as to cover the projected surface of the positive electrode active material layer,
The negative electrode tab has a size larger than at least the projected area of the negative electrode active material layer of the negative electrode end electrode, and is disposed on the current collector so as to cover the projected surface of the negative electrode active material layer. This is a bipolar battery.

  The present invention according to claim 12, which achieves the above object, is an assembled battery comprising a plurality of bipolar batteries electrically connected.

  The present invention according to claim 13 which achieves the above object is a vehicle on which a bipolar battery or an assembled battery is mounted.

  According to the first aspect of the present invention, a tab separate from the battery element is brought into planar contact with the current collector of the terminal electrode so as to cover the projection surface of the active material layer, and is necessary for taking out an electric current. Since the current flow along the plane direction is generated in the tab, even if the same material as the current collector of the bipolar electrode is used for the current collector of the terminal electrode, the current can be made uniform by suppressing variations in the current density distribution. It can be taken out.

  According to the present invention described in claim 12, a high-capacity, high-power battery can be obtained by connecting bipolar batteries in series or in parallel to form an assembled battery.

  According to the thirteenth aspect of the present invention, a vehicle on which a bipolar battery or an assembled battery is mounted is a vehicle having a long life and high reliability.

  Embodiments of the present invention will be described below with reference to the drawings. For easy understanding, each component is exaggerated in the drawings.

(First embodiment)
1A is a cross-sectional view showing the bipolar battery 10 according to the first embodiment of the present invention, and FIG. 1B is electrically connected to the current collector 21 at the terminal electrode of the battery element 30. It is a top view which shows the tab 50 (general name of the positive electrode tab 51 and the negative electrode tab 52). FIG. 2A is a cross-sectional view showing the bipolar electrode 20, and FIG. 2B is a cross-sectional view for explaining the single cell layer 32.

  Referring to FIGS. 1 and 2, a bipolar battery 10 is configured by housing a battery element 30 formed by connecting a plurality of bipolar electrodes 20 in series with an electrolyte layer 31 interposed therebetween in an outer case 40. In the bipolar electrode 20, a positive electrode active material layer 22 is provided on one surface of a current collector 21 to form a positive electrode 23, and a negative electrode active material layer 24 is provided on the other surface to form a negative electrode 25 (FIG. 2). (See (A)). In the battery element 30 in which the bipolar electrode 20 is laminated, a single battery layer 32 is constituted by the positive electrode active material layer 22, the electrolyte layer 31, and the negative electrode active material layer 24 sandwiched between adjacent current collectors 21 and 21. (See FIG. 2B). In the positive electrode terminal electrode 33 of the battery element 30, only the positive electrode active material layer 22 is provided on one surface of the current collector 21, and the electrolyte layer 31 is interposed on the uppermost bipolar electrode 20 in FIG. Laminated. The negative electrode terminal electrode 34 of the battery element 30 is provided with only the negative electrode active material layer 24 on one surface of the current collector 21, and the electrolyte layer 31 is disposed below the lowest bipolar electrode 20 in FIG. Laminated.

  In summary, the bipolar battery 10 of the first embodiment is a collection of the positive electrode tab 51 electrically connected to the current collector 21 of the positive electrode terminal pole 33 of the battery element 30 and the negative electrode terminal electrode 34 of the battery element 30. And a negative electrode tab 52 that is electrically connected to the electric body 21. The positive electrode tab 51 has a size larger than at least the projected area of the positive electrode active material layer 22 of the positive electrode terminal electrode 33, and is disposed on the current collector 21 so as to cover the projected surface of the positive electrode active material layer 22. ing. Similarly, the negative electrode tab 52 has a size larger than at least the projected area of the negative electrode active material layer 24 of the negative electrode end electrode 34, and is superimposed on the current collector 21 so as to cover the projected surface of the negative electrode active material layer 24. Are arranged.

  In the following description, the positive electrode tab 51 and the negative electrode tab 52 are collectively referred to as “tab 50”, and the positive electrode terminal electrode 33 and the negative electrode terminal electrode 34 are collectively referred to as “terminal electrode 35”. 22 and the negative electrode active material layer 24 are also collectively referred to as an “active material layer 26”. Further, when the current collector 21 of the terminal electrode 35 is designated, it is expressed as “end current collector 21e”. Further, the direction in which the bipolar electrodes 20 are stacked, that is, the thickness direction of the battery is referred to as “stacking direction”, and the direction orthogonal to the stacking direction, that is, the direction in which the current collector 21 and the tab 50 extend is referred to as “planar direction”.

  Hereinafter, the tab 50, the outer case 40, the current collector 21, the positive electrode 23 (positive electrode active material layer 22), the negative electrode 25 (negative electrode active material layer 24), and the electrolyte layer 31 in the bipolar battery 10 will be further described.

[Positive electrode tab 51, negative electrode tab 52]
The tab 50 disposed on the end current collector 21e has a function as a terminal for taking out current. The electrodes 23 and 25, the electrolyte layer 31 and the current collector 21 constituting the battery element 30 are all thin films and have low mechanical strength. For this reason, it is desirable to give the tab 50 enough strength to hold the battery element 30 from both sides. The thickness of the tab 50 is preferably about 0.1 mm to 2 mm from the viewpoint of suppressing internal resistance. The shape of the tab 50 is larger than the application area of the active material layer 26 as described above.

  The material of the tab 50 can be a material used in a lithium ion battery. For example, aluminum, copper, and other highly conductive materials are preferable. However, even if the material has low conductivity, if the thickness direction is increased, the resistance can be reduced to an acceptable level, and a sufficient flow of electricity in the planar direction can be ensured. Therefore, stainless steel (SUS) or the like having lower conductivity than aluminum or the like can be used. Aluminum is preferably used from the viewpoints of corrosion resistance, ease of production, economy, and the like. The material of the positive electrode tab 51 and the negative electrode tab 52 may be the same material or different materials.

  By processing the end portion of the tab 50 into a lead shape, the positive electrode lead portion 51 a and the negative electrode lead portion 52 a are formed integrally with the tab 50. The positive electrode lead portion 51a and the negative electrode lead portion 52a taken out from the outer case 40 are preferably covered with a heat-shrinkable heat-shrinkable tube or the like. This is to prevent the lead parts 51a and 52a from coming into contact with the heat source when the distance between the lead parts 51a and 52a and the heat source is small, and causing adverse effects on components (particularly electronic devices) due to electric leakage.

  In the region corresponding to the projection surface of the active material layer 26 in the end current collector 21 e, the current flows substantially along the lamination direction of the bipolar electrode 20. A metal tab 50 is placed on the end current collector 21e so as to cover the projection surface of the active material layer 26, whereby the active material layer 26 is located between the tab 50 and the end current collector 21e. Thus, the entire projection surface is electrically evenly joined. As a result, the tab 50 receives the current evenly from the entire surface of the end current collector 21e where the current substantially flows. Therefore, the variation in current density distribution is suppressed, and the promotion of deterioration due to the variation in current density is suppressed.

  The current flow along the planar direction necessary for taking out the current can be applied to the tab 50 disposed so as to overlap the end current collector 21e. By selecting the material and cross-sectional area of the tab 50, the resistance of the tab 50 can be reduced. Thereby, the electrical conductivity along the planar direction of the tab 50 can be easily increased as compared with the electrical conductivity along the planar direction of the current collector 21. Therefore, the loss at the time of taking out an electric current is reduced, and the high output of a battery is attained.

  Here, the resistance along the planar direction of the tab 50 is desirably low enough to ignore the resistance along the planar direction of the current collector 21. This is because only the tab 50 is responsible for the flow of electrons along the planar direction, and it is possible to further increase the output of the battery by reducing the resistance.

  Since the current is taken out using the tab 50 separate from the battery element 30, the current collector 21 of the battery element 30 can use the same type of material regardless of the bipolar electrode 20 and the terminal electrode 35. Thereby, there is no variation between the active material layer 26 in the terminal electrode 35 and the active material layer 26 in the bipolar electrode 20, and there is no variation in capacity and resistance between the single battery layers 32. Therefore, there is no possibility that the performance of the bipolar battery 10 is lowered.

  According to the bipolar battery 10 having the above-described configuration, the tab 50 separate from the battery element 30 is required to be brought into planar contact with the end current collector 21e so as to cover the projection surface of the active material layer 26 and to take out current. Since the current flow along the flat direction is generated in the tab 50, even if the same material as the current collector 21 of the bipolar electrode 20 is used for the end current collector 21e, the variation in the current density distribution is suppressed. The current can be taken out uniformly. In addition, the output of the battery can be increased by reducing the resistance. Furthermore, there is no possibility that the performance of the bipolar battery 10 is reduced.

  The positive electrode tab 51 is desirably larger than the outer area of the positive electrode terminal electrode 33 and higher in strength than the current collector 21 constituting the battery element 30. Similarly, the negative electrode tab 52 is desirably larger than the outer area of the negative electrode end electrode 34 and higher in strength than the current collector 21 constituting the battery element 30. This is because the electrode can be protected by making the tab 50 larger than the outer area of the terminal electrode 35.

  The current collector 21 constituting the battery element 30 is required to be thin in order to improve output. On the other hand, since the tab 50 arranged at the outermost part is not a member constituting the battery element 30, even if it is thicker than the current collector 21, the output is not reduced. Further, as described above, since the battery element 30 has a low mechanical strength, it is desirable that the tab 50 has a strength capable of sandwiching the battery element 30 from both sides. Therefore, the flatness and mechanical strength of the battery element 30 can be improved by increasing the thickness of the tab 50 that sandwiches the battery element 30 and making the strength higher than that of the current collector 21.

[Exterior case 40]
In the bipolar battery 10, the battery element 30 and the tab 50 are accommodated in the outer case 40 in order to mitigate an external impact during use and prevent environmental degradation. The outer case 40 is formed of a flexible sheet-like material, and seals the battery element 30, the positive electrode tab 51, and the negative electrode tab 52. Furthermore, the internal pressure of the outer case 40 is a pressure lower than the atmospheric pressure Pa. The tab 50 is merely placed on the end current collector 21e, and mechanical fastening is not performed between them. Conductivity between the tab 50 and the end current collector 21e is ensured by metal contact due to pressure acting when sealed by the outer case 40. An adhesive or non-adhesive coating agent excellent in conductivity may be interposed between the tab 50 and the end collector 21e. This is because the metal contact between the two becomes dense and the conductivity is more reliable.

  The sheet-like material may be a flexible material that can be easily deformed without being broken by a pressure difference between the inside and the outside of the outer case 40. The battery element 30 is pressurized from above and below in the figure via the tab 50 by hydrostatic pressure using atmospheric pressure Pa.

  If the connection between the tab 50 and the end current collector 21e is electrically non-uniform over the entire surface, the current density varies, which may promote deterioration. In the present embodiment, the relationship between the pressure inside the outer case 40 <the pressure outside the outer case 40 (= atmospheric pressure Pa) is satisfied by the hydrostatic pressure using the atmospheric pressure Pa. The entire surface of the junction with the current collector 21e is electrically uniform. Therefore, the variation in current density distribution is suppressed, and the promotion of deterioration due to the variation in current density is suppressed. In addition, the high output of the battery due to the low resistance of the tab 50 is also ensured.

  Further, the sheet-like material preferably exhibits electrical insulation without allowing electrolyte or gas to permeate and is chemically stable with respect to the material such as the electrolyte, and examples thereof include synthetic resins such as polyethylene, polypropylene, and polycarbonate. The

  As the sheet material, a laminate film 41 including a metal foil and a synthetic resin film can also be suitably applied. This is because it is preferable for reducing the heat sealing property of the outer case 40 and the possibility of air contact of the electrolyte and further reducing the weight. The laminate film 41 has a three-layer structure in which a metal foil 42 made of a metal (including an alloy) such as aluminum, stainless steel, nickel, or copper is covered with insulating synthetic resin films 43 and 44 such as a polypropylene film. In addition to the polymer-metal composite laminate film 41, an aluminum laminate pack can be used similarly.

  The polymer-metal composite laminate film 41, the aluminum laminate pack and the like are preferably excellent in thermal conductivity. This is because when mounted on an automobile, heat can be efficiently transmitted from the automobile heat source to the bipolar battery 10 and the battery element 30 can be quickly heated to the battery operating temperature.

  When the laminate film 41 is used for the outer case 40, the battery element 30 and the tab 50 are housed and sealed by joining a part or the whole of the peripheral portion of the laminate film 41 by heat fusion. The lead parts 51a and 52a are sandwiched between the heat-sealed parts and exposed to the outside of the laminate film 41.

  If the outer case 40 is applied to the laminate film 41 as in the present embodiment, the outer case 40 is easily deformed, and the hydrostatic pressure using the atmospheric pressure Pa can be applied to the battery element 30. Furthermore, since the layer of the metal foil 42 is present, the gas permeability is lowered, and the pressure difference between the inside and the outside can be maintained over a long period of time. As a result, the tab 50 and the end current collector 21e are stabilized. Electrical contact can be maintained over a long period of time.

[Current collector 21]
The current collector 21 of the present embodiment is made of stainless steel (SUS). Since stainless steel is stable with respect to both the positive electrode active material and the negative electrode active material, the active material layer 26 can be formed on each of the front and back surfaces of the single stainless steel layer.

  In the terminal electrode 35, the positive electrode active material layer 22 or the negative electrode active material layer 24 is formed only on one surface of the end current collector 21e.

  The thickness of the current collector 21 is not particularly limited, but is about 1 μm to 100 μm.

[Positive electrode 23 (positive electrode active material layer 22)]
The positive electrode 23 includes a positive electrode active material. In addition to this, a conductive aid, a binder, and the like may be included. The gel electrolyte is sufficiently infiltrated into the positive electrode 23 and the negative electrode 25 by chemical crosslinking or physical crosslinking.

As the positive electrode active material, a composite oxide of transition metal and lithium, 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.

  The particle diameter of the positive electrode active material is not limited as long as it can be formed into a paste by spraying the positive electrode material and spray coating or the like in order to reduce the electrode resistance of the bipolar battery 10. What is smaller than the generally used particle size used in the type of lithium ion battery may be used. Specifically, the average particle diameter of the positive electrode active material is preferably 0.1 μm to 10 μm.

  The polymer gel electrolyte is a solid polymer electrolyte having ion conductivity containing an electrolyte solution usually used in a lithium ion battery. Further, in the polymer skeleton having no lithium ion conductivity, In addition, those holding the same electrolytic solution are also included.

Here, the electrolyte solution (electrolyte salt and plasticizer) contained in the polymer gel electrolyte may be any electrolyte solution that is normally used in lithium ion batteries. For example, LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAsF ₆ , LiTaF. ₆ , inorganic acid anion salts such as LiAlCl ₄ and Li ₂ B ₁₀ Cl ₁₀ , organic acid anions such as LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, and Li (C ₂ F ₅ SO ₂ ) ₂ N Including at least one lithium salt (electrolyte salt) selected from ionic salts, cyclic carbonates such as propylene carbonate and ethylene carbonate; chain carbonates such as dimethyl carbonate, methyl ethyl carbonate, and diethyl carbonate; tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane Ethers such as 1,2-dimethoxyethane and 1,2-dibutoxyethane; Lactones such as γ-butyrolactone; Nitriles such as acetonitrile; Esters such as methyl propionate; Amides such as dimethylformamide; Methyl acetate Further, those using an organic solvent (plasticizer) such as an aprotic solvent in which at least one selected from methyl formate or a mixture of two or more thereof can be used. However, it is not necessarily limited to these.

  Examples of the polymer having ion conductivity include polyethylene oxide (PEO), polypropylene oxide (PPO), and copolymers thereof.

  For example, polyvinylidene fluoride (PVDF), polyvinyl chloride (PVC), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), etc. are used as the polymer having no lithium ion conductivity used for the polymer gel electrolyte. it can. However, it is not necessarily limited to these. Note that PAN, PMMA, etc. are in a class that has almost no ionic conductivity. Therefore, the PAN, PMMA, and the like can be used as a polymer having the ionic conductivity described above, but are used here as a polymer gel electrolyte. This is exemplified as a polymer having no lithium ion conductivity.

As the lithium salt, for _{example, LiPF 6, LiBF 4, LiClO} 4, LiAsF 6, LiTaF 6, LiAlCl 4, Li 2 B 10 Cl 10 and the like inorganic acid anion _{salts, Li (CF 3 SO 2)} 2 N, An organic acid anion salt such as Li (C ₂ F ₅ SO ₂ ) ₂ N 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.

  In the present embodiment, the electrolyte solution, lithium salt, and polymer (polymer) are mixed to prepare a pregel solution, and the positive electrode 23 and the negative electrode 25 are impregnated.

  The blending amount of the positive electrode active material, the conductive assistant and the binder in the positive electrode 23 should be determined in consideration of the intended use of the battery (emphasis on output, emphasis on energy, etc.) and ion conductivity. For example, if the amount of the electrolyte in the positive electrode 23, particularly the solid polymer electrolyte, 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 electrolyte in the positive electrode 23, particularly the solid polymer electrolyte, 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.

  The thickness of the positive electrode 23 is not particularly limited, and should be determined in consideration of the intended use of the battery (emphasis on output, emphasis on energy, etc.) and ion conductivity, as described for the blending amount. The thickness of the general positive electrode active material layer 22 is about 10 to 500 μm.

[Negative Electrode 25 (Negative Electrode Active Material Layer 24)]
The negative electrode 25 includes a negative electrode active material. In addition to this, a conductive aid, a binder, 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 of “Positive electrode 23”, 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. For example, metal oxide, lithium-metal composite oxide metal, carbon and the like are preferable. More preferred are carbon, transition metal oxide, and lithium-transition metal composite oxide. More preferred are titanium oxide, lithium-titanium composite oxide, and carbon. These may be used alone or in combination of two or more.

  In the present embodiment, the positive electrode active material layer 22 uses a lithium-transition metal composite oxide as the positive electrode active material, and the negative electrode active material layer 24 uses carbon or a lithium-transition metal composite as the negative electrode active material. An oxide is used. This is because a battery having excellent capacity and output characteristics can be configured.

[Electrolyte layer 31]
The electrolyte layer 31 is a layer composed of a polymer having ion conductivity, and the material is not limited as long as it exhibits ion conductivity.

  The electrolyte of this embodiment is a polymer gel electrolyte. As described above, after impregnating a pregel solution into a separator as a substrate, the electrolyte is used as a polymer gel electrolyte by chemical crosslinking or physical crosslinking.

  Such a polymer gel electrolyte is an all-solid polymer electrolyte having ion conductivity such as polyethylene oxide (PEO) containing an electrolytic solution usually used in a lithium ion battery. A polymer gel electrolyte that contains a similar electrolyte solution in a polymer skeleton having no lithium ion conductivity such as vinylidene (PVDF) is also included. Since these are the same as the polymer gel electrolyte described as a kind of electrolyte contained in the positive electrode 23, description thereof is omitted here. The ratio of the polymer and the electrolyte constituting the polymer gel electrolyte is wide. When 100% of the polymer is an all-solid polymer electrolyte and 100% of the electrolyte is a liquid electrolyte, all of the intermediates correspond to the polymer gel electrolyte. The term “polymer electrolyte” includes both a polymer gel electrolyte and an all solid polymer electrolyte.

  The polymer gel electrolyte can be included in the positive electrode 23 and / or the negative electrode 25 as described above, in addition to the polymer electrolyte constituting the battery. However, the polymer gel electrolyte is different depending on the polymer electrolyte constituting the battery, the positive electrode 23, and the negative electrode 25. Molecular electrolytes may be used, the same polymer electrolyte may be used, or different polymer electrolytes may be used depending on the layer.

  The thickness of the electrolyte constituting the battery is not particularly limited. However, in order to obtain a compact bipolar battery 10, it is preferable to make it as thin as possible within a range that can ensure the function as an electrolyte. The thickness of the general solid polymer electrolyte layer 31 is about 10 to 100 μm. However, the shape of the electrolyte can be easily formed so as to cover the upper surface of the electrode (positive electrode 23 or negative electrode 25) as well as the outer peripheral portion of the side by taking advantage of the manufacturing method. It is not always necessary to have a substantially constant thickness.

  In the bipolar battery 10, when the electrolyte solution contained in the electrolyte layer 31 oozes out, the layers are electrically connected to each other and do not function as a battery. This is called a liquid junction.

  When a liquid or semi-solid gel substance is used for the electrolyte layer 31, it is necessary to seal between the current collectors 21 so that the electrolyte does not leak. Therefore, as shown in FIG. 1, a seal member 36 is provided between the current collectors 21 so as to surround the unit cell layer 32. The seal member 36 is, for example, a double-sided tape in which an adhesive material is applied to both surfaces 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. The sealing member 36 prevents liquid leakage from the single cell layer 32 and prevents a short circuit due to contact between the current collectors 21.

  The electrolyte layer 31 can also use a solid electrolyte. This is because by using a solid as the electrolyte, it is possible to prevent liquid leakage, preventing a liquid junction that is a problem peculiar to bipolar batteries, and providing a highly reliable bipolar battery. In addition, since a configuration for preventing leakage is not required, the configuration of the bipolar battery can be simplified.

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. Polyalkylene oxide polymers 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.

  As described above, according to the bipolar battery 10 of the first embodiment, even if the same material as that of the current collector 21 of the bipolar electrode 20 is used for the end current collector 21e, variation in the current density distribution is suppressed. The current can be taken out uniformly. In addition, the output of the battery can be increased by reducing the resistance.

(Modification example)
In the first embodiment, the case where the end portion of the tab 50 is formed in a lead shape is illustrated. However, in the bipolar battery of the present invention, the tab 50 itself needs to extend outward from the outer case 40. Absent. The bipolar battery includes, for example, a rectangular tab that is in flat contact with the end current collector 21e and is accommodated in the outer case 40, and leads that are attached to the tab by welding and extend outward from the outer case 40. May be. As this lead, a known lead used in a lithium ion battery or the like can be used.

  The case where the tab 50 is brought into close contact with the end current collector 21e by hydrostatic pressure using atmospheric pressure Pa is exemplified. However, in the bipolar battery of the present invention, the pressure inside the outer case 40 <the pressure outside the outer case 40 As long as this relationship is satisfied, the medium that generates the hydrostatic pressure is not limited. For example, the tab 50 may be brought into close contact with the end current collector 21e by hydrostatic pressure using at least one medium of gas, liquid, or solid powder, or a medium obtained by mixing them.

(Second Embodiment)
3A is a cross-sectional view showing the bipolar battery 11 according to the second embodiment of the present invention, and FIG. 3B is a tab electrically connected to the end current collector 21e of the battery element 30. 55 is a plan view showing 55 (a general term for the positive electrode tab 53 and the negative electrode tab 54). In addition, the same code | symbol is attached | subjected to the member which is common in the member shown in FIG.1 and FIG.2, and the description is abbreviate | omitted. In FIG. 3A, the bowl shape of the tab 55 is exaggerated.

  The second embodiment is different from the first embodiment in that the shape of the tab 55 is modified. In the bipolar battery 11 of the second embodiment, the positive electrode tab 53 and the negative electrode tab 54 are formed such that the thickness along the direction in which the bipolar electrodes 20 are laminated is thicker in the center than in the periphery.

  When the electrolyte layer 31 is sealed with the seal member 36, the thickness of the electrode peripheral portion where the seal member 36 is disposed may be increased and the electrode may be warped. In this case, there is a possibility that the pressing of the central portion of the electrode becomes insufficient. By making the shape of the tab 55 into the bowl shape as described above, sufficient pressure can be applied even if the electrode peripheral portion is warped, and the pressure acting from above and below the bipolar battery 11 is made more uniform. Thereby, the electrical contact between the tab 50 and the end current collector 21e is made more uniform, the variation in the current density distribution is suppressed, and the deterioration caused by the variation in the current density is further suppressed.

  In addition, it is good also as a bipolar battery which changed only any one of the positive electrode tab 53 or the negative electrode tab 54 in the shape mentioned above.

(Third embodiment)
FIG. 4 is a cross-sectional view showing a bipolar battery 12 according to a third embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the member which is common in the member shown in FIG.1 and FIG.2, and the description is abbreviate | omitted.

  The third embodiment is different from the first embodiment in that the tab 50 further includes a magnetic body 80. In the bipolar battery 12 of the third embodiment, the positive electrode tab 51 and the negative electrode tab 52 have the magnetic body 80 disposed on the surface opposite to the surface in contact with the end current collector 21e. .

  The magnetic body 80 has a plate shape substantially equal to the size of the end current collector 21e. The magnetic body 80 is a permanent magnet, for example. Although the kind of permanent magnet is not limited, For example, a rare earth Samakova magnet can be mentioned. The magnetization (magnetization) direction of the magnetic body 80 is the thickness direction.

  The end current collector 21e is preferably formed from martensitic stainless steel which is a ferromagnetic material. Since the tab 50 is sandwiched between the end current collector 21 e and the magnetic body 80, the tab 50 is pressed against the end current collector 21 e by the magnetic force of the magnetic body 80.

  In the bipolar battery 12, the tab 50 is pressed against the end current collector 21e by the hydrostatic pressure using the atmospheric pressure Pa, similarly to the bipolar battery 11 of the first embodiment. In addition to this, in the bipolar battery 12, the tab 50 is pressed against the end current collector 21 e by the magnetic force Pm of the magnetic body 80. Therefore, the entire surface of the joint between the tab 50 and the end current collector 21e is electrically more uniform. Therefore, the variation in current density distribution is further suppressed, and the promotion of deterioration due to the variation in current density is further suppressed. In addition, higher output of the battery by lowering the resistance of the tab 50 is more reliable.

  Both the positive electrode tab 51 and the negative electrode tab 52 do not need to have the magnetic body 80, and at least one of the positive electrode tab 51 and the negative electrode tab 52 only needs to have the magnetic body 80. The magnetic body 80 is disposed only on one of the positive electrode tab 51 and the negative electrode tab 52, and the opposite surface of the surface of the other tab that is in contact with the end current collector 21e is iron, which is a ferromagnetic material, You may employ | adopt the form which arrange | positions cobalt, nickel, aluminum which is a paramagnetic substance, etc.

  5-7 is a figure which shows the example of a shape of the magnetic body 80. FIG.

  With reference to FIGS. 5A to 5E, the magnetic body 80 may have a shape that radially extends from the position of the center of gravity toward the outer peripheral portion. The presence of the magnetic body 80 radially from the position of the center of gravity makes the magnetic body 80 itself a skeleton and exerts a reinforcing role against distortion. When the bipolar battery 12 is mounted on a vehicle to which vibration is applied, the magnetic body 80 itself becomes a reinforcing member, and the rigidity of the bipolar battery 12 can be increased.

  6A to 6D, the magnetic body 80 may have a circular or rectangular through hole 81. By having the through hole 81, a space is created, and the volume of the magnetic body 80 is reduced. When the magnetic body 80 is viewed as a spring, the spring constant is lowered and a vibration isolation effect is exhibited. When the bipolar battery 12 is mounted on a vehicle to which vibration is applied, the magnetic body 80 itself becomes a vibration absorbing material in the battery stacking direction, and the magnetic body 80 itself becomes a reinforcing member to increase the rigidity of the bipolar battery 12. be able to.

  With reference to FIGS. 7A to 7D, the magnetic body 80 may have a concave portion 82 formed on the surface thereof and having a cross-sectional shape of a bottom surface of an arc shape or a square shape. By having the recess 82, a space is created, and the volume of the magnetic body 80 is reduced. When the magnetic body 80 is viewed as a spring, the spring constant is lowered and a vibration isolation effect is exhibited. When the bipolar battery 12 is mounted on a vehicle to which vibration is applied, the magnetic body 80 itself becomes a vibration absorbing material in the battery stacking direction, and the magnetic body 80 itself becomes a reinforcing member to increase the rigidity of the bipolar battery 12. be able to.

(Fourth embodiment)
FIG. 8 is a perspective view showing an assembled battery 60 according to the fourth embodiment, and FIG. 9 is a view of the internal configuration of the assembled battery 60 as viewed from above.

  The assembled battery 60 is configured by electrically connecting a plurality of the above-described bipolar batteries in parallel and / or in series. By paralleling and / or serializing, the capacity and voltage can be freely adjusted.

  The illustrated assembled battery 60 is obtained by connecting a plurality of bipolar batteries 10 of the first embodiment connected in series and further connected in parallel. In each uppermost bipolar battery 10, the positive electrode lead portions 51 a are connected to each other by a conductive bar 63, and the negative electrode lead portions 52 a are connected to each other by a conductive bar 63. As electrodes of the assembled battery 60, electrode terminals 61 and 62 are provided on one side surface of the assembled battery 60.

  In the assembled battery 60, ultrasonic welding, heat welding, laser welding, rivets, caulking, electron beam, or the like can be used as a method of connecting the bipolar batteries 10 to each other. By adopting such a connection method, the assembled battery 60 having long-term reliability can be manufactured.

  According to the fourth embodiment, since the bipolar battery 10 is connected in series or in parallel to form the assembled battery 60, a high-capacity, high-power battery can be obtained. In addition, the individual bipolar battery 10 is highly reliable because the liquid junction in the internal cell layer 32 is prevented, and the long-term reliability of the assembled battery 60 can be improved.

  Depending on the required capacity and voltage, an assembled battery in which all of the plurality of bipolar batteries 10 are connected in parallel or an assembled battery in which all are connected in series can be used.

(Fifth embodiment)
FIG. 10 is a perspective view showing an assembled battery module 70 according to the fifth embodiment.

  The illustrated assembled battery module 70 is obtained by stacking a plurality of assembled batteries 60 of the third embodiment and connecting the electrode terminals 61 and 62 of each assembled battery 60 with conductive bars 71 and 72 to form a module.

  Thus, by making the assembled battery 60 into a module, the control of the battery is facilitated, and, for example, the assembled battery module 70 is optimal for in-vehicle use such as an electric vehicle and a hybrid vehicle. The assembled battery module 70 uses the above-described assembled battery 60 and thus has high long-term reliability.

  Note that the term “assembled battery module” is used to make it easier to understand the difference in battery size in comparison with “assembled battery”. The assembled battery module 70 is also a kind of the assembled battery 60 in that a plurality of the bipolar batteries 10 are electrically connected.

(Sixth embodiment)
FIG. 11 is a schematic configuration diagram showing an automobile 100 as a vehicle according to the sixth embodiment.

  It is desirable that the above-described bipolar batteries 10, 11, 12, or the assembled battery 60 (including the assembled battery module 70) be mounted on a vehicle and used as a power source for an electric device such as a motor. This is because the bipolar batteries 10, 11, 12 and the assembled battery 60 have the above-described characteristics, and thus a vehicle on which these batteries are mounted becomes a long-life and highly reliable vehicle.

  The illustrated automobile 100 includes the assembled battery module 70 according to the fifth embodiment, and uses the assembled battery module 70 as a power source for the motor. Examples of the automobile using the assembled battery module 70 as a motor power source include an electric car, a hybrid car, and a car in which each wheel is driven by a motor. Since the assembled battery module 70 has the above-described characteristics, the automobile 100 on which the assembled battery module 70 is mounted is an automobile having a long life and high reliability.

  The vehicle is not limited to the automobile 100, and the same effects can be obtained even if the bipolar batteries 10, 11, 12 and the assembled battery 60 are mounted on a train.

(Example)
Examples of bipolar batteries will be described below. The produced bipolar battery is as follows.

<Basic configuration>
As the current collector 21, a stainless steel (SUS) foil (thickness 20 μm) was used. The following positive electrode 23 and negative electrode 25 were formed on the current collector 21 to produce a bipolar electrode 20. Either the positive electrode 23 or the negative electrode 25 was formed on the end current collector 21e.

<Formation of electrode>
Positive electrode 23:
LiMn ₂ O ₄ (85% by weight) as a positive electrode active material, acetylene black (5% by weight) as a conductive auxiliary agent, polyvinylidene fluoride (PVDF) (10% by weight) as a binder, N-methyl-as a slurry viscosity adjusting solvent 2-Pyrrolidone (NMP) (appropriate amount) was added and mixed to prepare a positive electrode slurry. A positive electrode slurry was applied to one side of a stainless steel foil (thickness 20 μm) that was a current-collection holiday, and dried to form a positive electrode 23.

Negative electrode 25:
Hard carbon (90 wt%) as a negative electrode active material, PVDF (10 wt%) as a binder, NMP (appropriate amount) as a slurry viscosity adjusting solvent were mixed, and these were mixed to prepare a negative electrode 25 slurry. A negative electrode slurry was applied to the opposite surface of the stainless steel foil coated with the positive electrode 23 and dried to form a negative electrode 25.

  The completed electrode was cut to 130 mm × 80 mm. The electrode portion of the outer peripheral 10 mm portion was scraped to form a seal layer.

<Formation of gel electrolyte>
A polyethylene separator (thickness: 50 μm) is charged with 3% by weight of 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, and an electrolyte solution of PC + EC ( 1: 1) A pregel solution composed of 97% by weight, 1.5M LiBF ₄ and a polymerization initiator (BDK) is immersed, sandwiched between quartz glass substrates and irradiated with ultraviolet rays for 15 minutes to crosslink the precursor, and polymer electrolyte A layer was obtained.

<Configuration of bipolar battery>
The bipolar electrode 20 was laminated so that the positive electrode 23 and the negative electrode 25 were opposed to each other with the gel electrolyte interposed therebetween, and a single cell layer 32 was formed. At the periphery of the unit cell layer 32, a sealant composed of a three-layer film was sandwiched between the current collector 21 and the current collector 21. This functions as a seal member 36 for suppressing electrolyte leakage.

  This was repeated, and the bipolar electrode 20 and the terminal electrode 35 were laminated so that five single battery layers 32 were formed, thereby constituting an electrode laminate.

  The sealant was first heat-sealed on three sides, and then the last side was vacuum-sealed, whereby each layer was vacuum-sealed, and the electrolyte in each layer was sealed.

  Through the above steps, a bipolar battery element 30 of 5 layers 21V was completed in which each layer was vacuum-sealed and the upper and lower surfaces were positive and negative terminal electrodes 35.

(Comparative example)
As shown in FIG. 12, the terminal 37 used for taking out an electric current was attached to the edge part of the edge part collector 21e using the ultrasonic welder. Thereafter, the battery element 30 was vacuum-sealed in an aluminum laminate exterior to complete a bipolar battery.

Example 1
Like the tab 50 in 1st Embodiment shown in FIG. 1, it is a 130 mm x 80 mm aluminum (Al) board which can cover the whole projection surface of the bipolar battery element 30, Comprising: Thickness is 100 micrometers. A positive electrode tab 51 and a negative electrode tab 52 in which a part of a flat plate-shaped aluminum (Al) plate extends to the outside of the battery projection surface to form lead portions 51a and 52a were produced. The bipolar battery element 30 was sandwiched between these tabs 50, and was vacuum-sealed with an aluminum laminate sheath so as to cover them. By pressing the entire bipolar battery element 30 from both sides at atmospheric pressure Pa, the bipolar battery 10 according to Example 1 in which the contact between the tab 50 and the battery element 30 was increased by pressurization was completed.

(Example 2)
Like the tab 55 in the second embodiment shown in FIG. 3, a 130 mm × 80 mm aluminum (Al) plate that can cover the entire projection surface of the bipolar battery element 30, and has a center thickness of 500 μm. A positive electrode tab 53 in which a part of a bowl-shaped aluminum (Al) plate whose outer peripheral portion has a thickness of 50 μm and becomes thicker toward the center extends to the outside of the battery projection surface to form lead portions 53a and 54a. And the negative electrode tab 54 was created. The bipolar battery element 30 was sandwiched between these tabs 55 and was vacuum-sealed with an aluminum laminate sheath so as to cover them. By pressing the entire bipolar battery element 30 from both sides at atmospheric pressure Pa, the bipolar battery 11 according to Example 2 in which the contact between the tab 55 and the battery element 30 was increased by pressurization was completed.

(Example 3)
Like the tab 50 in the third embodiment shown in FIG. 4, a 130 mm × 80 mm aluminum (Al) plate that can cover the entire projection surface of the bipolar battery element 30 and has a thickness of 100 μm. A positive electrode tab 51 and a negative electrode tab 52 in which a part of a flat plate-shaped aluminum (Al) plate extends to the outside of the battery projection surface to form lead portions 51a and 52a were produced. The bipolar battery element 30 was sandwiched between these tabs 50, a flat magnetic plate having a thickness of 5 mm was disposed so as to cover the outside, and vacuum sealed with an aluminum laminate exterior so as to cover them. The contact between the tab 50 and the battery element 30 is increased by pressurization (atmospheric pressure + magnetic force) by pressing the entire bipolar battery element 30 from both sides at atmospheric pressure Pa and further pressing from both sides by the magnetic force Pm of the magnetic plate. In addition, the bipolar battery 12 according to Example 3 was completed.

(Reference Example 1)
As Reference Examples 1 to 5, a bipolar battery in which the contact between the tab and the battery element was increased only by magnetic force without vacuum sealing the aluminum laminate exterior was completed.

  A bipolar battery according to Reference Example 1 was completed in the same manner as in Example 3 except that the aluminum laminate exterior was not vacuum-sealed.

(Reference Example 2)
A bipolar battery element is sandwiched between tabs, a flat magnetic plate having a thickness of 5 mm is arranged on one of the outer sides thereof, and a flat nickel plate having a thickness of 5 mm is arranged on the other side. A bipolar battery according to Example 2 was completed.

(Reference Example 3)
A bipolar battery according to Reference Example 3 was completed using the magnetic material plate having the shape shown in FIG.

(Reference Example 4)
A bipolar battery according to Reference Example 4 was completed by using the magnetic plate having the shape shown in FIGS. 6A and 6B, and making the rest the same as Reference Example 1.

(Reference Example 5)
A bipolar battery according to Reference Example 5 was completed by using the magnetic plate having the shape shown in FIGS. 7A and 7B, and making the rest the same as Reference Example 1.

  As the magnetic plate in the examples and reference examples, a rare earth Samakoba magnet was used (surface magnetic flux density: 4000 gauss, attractive force: 12 kg).

<Evaluation>
Each of the bipolar batteries of Comparative Example and Examples 1 and 2 was charged with constant current and constant voltage (CCCV) up to 21 V for 15 hours at a current corresponding to 0.1 C.

  These bipolar batteries were sequentially discharged at 10 mA, 20 mA, and 30 mA, and the resistance value of each bipolar battery was measured by measuring the voltage drop.

  Moreover, it was 20 mAh as a result of measuring a capacity | capacitance.

  Thereafter, charging and discharging were repeated at 21 V to 12.5 V at a relatively large current of 500 mA (corresponding to 25 C), and 1000 cycles were performed. Thereafter, capacity measurement was performed.

  About Comparative Example and Reference Examples 3, 4, and 5, charging and discharging were repeated at 21 V to 12.5 V at a current of 100 mA (corresponding to 5 C) while shaking, and 1000 cycles were performed. The shaking test was performed at 50 Hz and the amplitude was 5 mm. Thereafter, capacity measurement was performed.

<Result>
Table 1 shows the resistance value of the bipolar battery measured at each current.

  In Examples 1 and 2, the resistance value was greatly reduced compared to the comparative example. In the comparative example, the current flows in the lateral direction (the plane direction in which the current is extracted) in the portion of the current collector made of stainless steel (SUS), which is the outermost layer, and the resistance value of the bipolar battery is increased. On the other hand, in Examples 1 and 2, since the tabs 50 and 55 cover the entire battery element 30 and the atmospheric pressure Pa holds the entire battery element 30, aluminum superior in conductivity compared to stainless steel. It is considered that the resistance value of the bipolar batteries 10 and 11 is reduced because the current flows in the lateral direction in the tabs 50 and 55 made of

  The resistance value of Example 3 was further reduced than that of Examples 1 and 2. In Example 3, since the entire battery element 30 is pressed by the magnetic force Pm of the magnetic plate in addition to the atmospheric pressure Pa, the contact force between the tab and the end current collector is further increased, and the resistance value of the bipolar battery 12 is increased. Is considered to be further reduced.

  When the entire battery element was pressed only by the magnetic force of the magnetic plates of Reference Examples 1 to 5, the resistance value was slightly higher than that of Example 3, but the resistance value was greatly reduced compared to the comparative example.

  Next, Table 2 shows the results of capacity measurement after 1000 cycles of charge and discharge.

  In Examples 1 and 2, the capacity was significantly increased compared to the comparative example. In the comparative example, since the terminal 37 is attached to the end portion of the terminal pole 35, the current density distribution largely varies, and as a result, the deterioration is promoted. In Examples 1 and 2, since the tabs 50 and 55 cover the entire battery element 30 and the atmospheric pressure Pa holds the entire battery element 30, variation in current density distribution can be suppressed and deterioration is small. Conceivable.

  Between Example 1 and Example 2, it turned out that Example 2 is further less deteriorated than Example 1, and is superior to Example 1 in terms of suppressing the promotion of deterioration. In the second embodiment, since the tab 55 has a bowl shape, the entire battery element 30 is pushed more evenly, the electrical contact between the tab 55 and the end current collector 21e is made uniform, and the current density is made uniform. This is probably because the promotion of deterioration was further suppressed.

  Next, Table 3 shows the results of capacity measurement after 1000 cycles of charge / discharge while shaking.

  From the capacity measurement after the shaking test, it was found that the use of a magnetic plate having the shape as in Reference Examples 3 to 5 is strong against vibration and an anti-vibration effect can be obtained.

1A is a cross-sectional view showing a bipolar battery according to a first embodiment of the present invention, and FIG. 1B is a tab (positive electrode) electrically connected to a current collector of a terminal electrode of a battery element. It is a top view which shows a tab and the general term of a negative electrode tab. FIG. 2A is a cross-sectional view showing a bipolar electrode, and FIG. 2B is a cross-sectional view for explaining a single cell layer. 3A is a cross-sectional view showing a bipolar battery according to a second embodiment of the present invention, and FIG. 3B is a tab (positive electrode) electrically connected to a current collector of a terminal electrode of the battery element. It is a top view which shows a tab and the general term of a negative electrode tab. It is sectional drawing which shows the bipolar battery which concerns on the 3rd Embodiment of this invention. It is a figure which shows the example of a shape of a magnetic body. It is a figure which shows the example of a shape of a magnetic body. It is a figure which shows the example of a shape of a magnetic body. It is a perspective view which shows the assembled battery which concerns on 4th Embodiment. It is drawing which looked at the internal structure of the assembled battery from upper direction. It is a perspective view which shows the assembled battery module which concerns on 5th Embodiment. It is a schematic block diagram which shows a motor vehicle as a vehicle which concerns on 6th Embodiment. It is sectional drawing which shows the comparative example which attached the terminal used in order to take out an electric current in the edge part of the electrical power collector of the terminal pole of a battery element.

Explanation of symbols

10, 11, 12 Bipolar battery,
20 bipolar electrodes,
21 current collector,
21e end current collector (terminal electrode current collector),
22 positive electrode active material layer,
23 positive electrode,
24 negative electrode active material layer,
25 negative electrode,
26 active material layer (generic name of positive electrode active material layer and negative electrode active material layer),
30 battery elements,
31 electrolyte layer,
32 cell layer,
33 Positive electrode terminal electrode,
34 Negative terminal pole,
35 terminal electrode (generic name for positive electrode terminal electrode and negative electrode terminal electrode),
36 sealing member,
40 exterior case,
41 Laminate film,
42 metal foil,
43, 44 Synthetic resin film,
50, 55 tab (generic name for positive electrode tab and negative electrode tab),
51, 53 positive electrode tab,
51a, 53a positive electrode lead part,
52, 54 negative electrode tab,
52a, 54a negative electrode lead,
60 battery packs,
70 assembled battery module (assembled battery),
80 magnetic material,
81 through hole,
82 recess,
100 automobile (vehicle),
Pa atmospheric pressure,
Pm Magnetic force.

Claims (13)

Bipolar battery in which a battery element formed by connecting a plurality of bipolar electrodes in which a positive electrode is formed on one surface of a current collector and a negative electrode is formed on the other surface in series through an electrolyte layer is housed in an outer case In
A positive electrode tab electrically connected to a current collector of a positive electrode terminal electrode of the battery element;
A negative electrode tab electrically connected to the current collector of the negative electrode terminal electrode of the battery element,
The positive electrode tab has a size larger than at least the projected area of the positive electrode active material layer of the positive electrode terminal electrode, and is disposed on the current collector so as to cover the projected surface of the positive electrode active material layer,
The negative electrode tab has a size larger than at least the projected area of the negative electrode active material layer of the negative electrode end electrode, and is disposed on the current collector so as to cover the projected surface of the negative electrode active material layer. A bipolar battery characterized by that. The positive electrode tab is larger than the outer area of the positive electrode end electrode and higher in strength than the current collector constituting the battery element,
2. The bipolar battery according to claim 1, wherein the negative electrode tab is larger than an outer area of the negative electrode end electrode and has a higher strength than a current collector constituting a battery element. The outer case is formed from a flexible sheet-like material, and seals the battery element, the positive electrode tab, and the negative electrode tab,
The bipolar battery according to claim 1, wherein an internal pressure of the outer case is lower than an atmospheric pressure.   The bipolar battery according to claim 3, wherein the sheet-like material is a laminate film including a metal foil and a synthetic resin film.   2. The bipolar battery according to claim 1, wherein the positive electrode tab and / or the negative electrode tab has a thickness along a direction in which the bipolar electrodes are laminated, and a central portion is thicker than a peripheral portion.   The at least one of the said positive electrode tab and the said negative electrode tab has a magnetic body arrange | positioned on the surface on the opposite side to the surface which contact | connects the said collector of the said terminal pole. Bipolar battery.   The bipolar battery according to claim 6, wherein the magnetic body has a shape that expands radially from the position of the center of gravity toward the outer periphery.   The bipolar battery according to claim 6, wherein the magnetic body has a circular or rectangular through hole.   The bipolar battery according to claim 6, wherein the magnetic body has a concave portion formed on a surface thereof and having a cross-sectional shape of a bottom surface of an arc shape or a square shape.   The bipolar battery according to claim 1, wherein a solid electrolyte is used for the electrolyte layer. The positive electrode active material layer uses a lithium-transition metal composite oxide as a positive electrode active material,
The bipolar battery according to claim 1, wherein the negative electrode active material layer uses carbon or a lithium-transition metal composite oxide as a negative electrode active material.   An assembled battery comprising a plurality of the bipolar batteries according to claim 1 electrically connected.   A vehicle comprising the bipolar battery according to claim 1 or the battery pack according to claim 12.

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