JP5070703B2 - Bipolar battery - Google Patents

Description

  The present invention relates to a bipolar battery, a battery module using the same, and a battery pack in which a plurality of battery modules are electrically connected.

  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 a high output density (see Patent Document 1).

  A typical bipolar battery has a battery element in which a plurality of bipolar electrodes are connected in series, that is, stacked with an electrolyte layer interposed therebetween, an outer packaging material that encloses and seals the entire battery element, and a current source. And an electrode terminal led out from the exterior material. 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. A single battery layer is formed by sequentially stacking a positive electrode active material layer, an electrolyte layer, and a negative electrode active material layer, and the single battery layer is sandwiched between a pair of current collectors. Bipolar batteries have the advantage that a current path is short and current loss is small because current flows in the direction of stacking bipolar electrodes in the battery element, that is, in the thickness direction of the battery.

  In addition, in order to obtain the required capacity and voltage, a plurality of bipolar batteries are electrically connected to form a battery module, or a plurality of battery modules are electrically connected to form an assembled battery. I do. The battery module is a type of assembled battery in that it has a structure in which a plurality of bipolar batteries are electrically connected. In this specification, a unit unit for assembling an “assembled battery” is used. It will be referred to as a “battery module”.

In the bipolar battery, battery elements are formed by stacking single battery layers in series as described above, and current flows linearly from one end of the battery element to the other end. In a conventional bipolar battery, the current collector is exposed without forming an active material layer on the outer layer of the bipolar electrode located at both ends, and the positive electrode terminal and the negative electrode terminal are brought into surface contact with the exposed current collector, respectively. In general, the current is taken out to the external circuit by joining them together.
JP 2004-158306 A

  By the way, metals such as stainless steel (SUS) are usually used as the current collector of the bipolar electrode constituting the battery element. In addition, as an electrode terminal connected to the exposed current collector located in the outermost layer, for example, a metal such as aluminum (especially preferred as the positive electrode side) or copper (especially preferred as the negative electrode side) is generally used. Yes. Therefore, in the outermost layer of the battery element, conduction is ensured by surface contact between the metals, and current is taken out to the external circuit.

  However, contact resistance exists at a site where the metals are in surface contact. This contact resistance acts as a cause of an increase in the internal resistance of the battery and may result in a decrease in the output of the battery. Such an increase in internal resistance is unlikely to be a problem in consumer batteries intended to extract a minute current. On the other hand, the present inventors have found that even if the internal resistance is slightly increased in a battery (for example, a battery as a power source for driving a vehicle) that is required to exhibit a high output over a long period of time. It has been found that a significant decrease in output often appears.

  Therefore, the present invention provides means for reducing contact resistance caused by direct joining of metals when taking out current from a battery element to an external circuit, thereby reducing internal resistance of the battery and improving output characteristics. The purpose is to provide.

  As a means for solving the above problems, the present invention provides a bipolar electrode in which a positive electrode active material layer is formed on one surface of a current collector and a negative electrode active material layer is formed on the other surface through an electrolyte layer. A plurality of laminated bodies and a single cell layer formed by laminating the positive electrode active material layer, the electrolyte layer, and the negative electrode active material layer are disposed around each of the single cell layers and the outside air. A bipolar battery having a battery element including a sealing portion for blocking, wherein at least one of the positive electrode side outermost layer current collector and the negative electrode side outermost layer current collector has a conductive material on a surface facing the electrolyte layer A bipolar battery is provided in which a conductive layer containing is formed.

  According to the present invention, the contact resistance caused by the contact between metals in the outermost layer portion of the conventional bipolar battery can be reduced. Therefore, in the bipolar battery of the present invention, the battery module or the assembled battery using the battery, the internal resistance is reduced, and the output performance can be improved.

  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)
A first aspect of the present invention is a laminate in which a plurality of bipolar electrodes each having a positive electrode active material layer formed on one surface of a current collector and a negative electrode active material layer formed on the other surface are stacked via an electrolyte layer. And a seal part disposed around each of the unit cell layers formed by laminating the positive electrode active material layer, the electrolyte layer, and the negative electrode active material layer, and blocking contact between the unit cell layer and outside air. A bipolar battery having a battery element including a positive electrode side outermost current collector or a negative electrode side outermost layer current collector, wherein a conductive layer containing a conductive material is formed on a surface facing the electrolyte layer. It is a bipolar battery characterized by the above.

  FIG. 1 is a cross-sectional view showing the bipolar battery of the first embodiment.

  A bipolar battery 10 according to this embodiment shown in FIG. 1 includes a substantially rectangular battery element 21 in which a charge / discharge reaction actually proceeds. The battery element 21 includes a stacked body 23 in which a plurality of bipolar electrodes 20 are stacked via an electrolyte layer 17, and a seal portion 31. Here, the bipolar electrode 20 has a structure in which the positive electrode active material layer 13 is formed on one surface of the current collector 11 and the negative electrode active material layer 15 is formed on the other surface.

  As described above, each bipolar electrode 20 is stacked via the electrolyte layer 17 to form the stacked body 23. At this time, the positive electrode active material layer 13 of one bipolar electrode 20 and the negative electrode active material layer 15 of another bipolar electrode 20 adjacent to the one bipolar electrode 20 face each other through the electrolyte layer 17. Each bipolar electrode 20 and the electrolyte layer 17 are laminated. In the form shown in FIG. 1, the electrolyte layer 17 is composed of a separator and an electrolyte held in the separator.

  The adjacent positive electrode active material layer 13, electrolyte layer 17, and negative electrode active material layer 15 constitute one unit cell layer 19. Therefore, it can be said that the bipolar battery 10 has a configuration in which the single battery layers 19 are stacked. The single battery layer 19 is sandwiched between adjacent current collectors 11 in a battery element 21 in which bipolar electrodes 20 are stacked. The bipolar battery shown in FIG. 1 has six single battery layers 19, but the number of single battery layers 19 can be arbitrarily selected. The thickness of the bipolar battery 10 having the six battery cell layers 19 is, for example, about 300 to 700 μm.

  The seal portion 31 is disposed around each of the unit cell layers 19 formed by laminating the positive electrode active material layer 13, the electrolyte layer 17, and the negative electrode active material layer 15, and makes contact between the unit cell layer 19 and the outside air. Has the function of blocking. Thereby, the short circuit (liquid junction) by the liquid leakage which may arise when using a liquid or semi-solid gel electrolyte can be prevented. Further, the seal portion 31 can also prevent the reaction between air or moisture contained in the air and the active material.

  Hereinafter, a characteristic configuration of the bipolar battery 10 of the present embodiment will be described in detail.

  In the bipolar battery 10 of this embodiment, the positive electrode side having the same configuration (composition, thickness, etc.) as the negative electrode active material layer 15 on the surface of the positive electrode side outermost layer current collector 11a facing the electrolyte layer 17a. It is characterized in that the conductive layer 33a is formed. On the other hand, in the negative electrode side outermost layer current collector 11b, the negative electrode active material layer 15 is formed on the surface on the electrolyte layer 17b side, and the surface facing the electrolyte layer 17b is exposed. In the present invention, the concept that “the composition of the conductive layer is the same as that of the active material layer” includes that the conductive layer does not contain an electrolyte even when the active material layer contains an electrolyte as described later. Cases are also included. This is because the battery reaction does not proceed in the conductive layer, and the active material slurry used when forming the active material layer on the surface of the current collector does not contain an electrolyte, This is because the electrolyte contained in the electrolyte layer permeates into the electrode due to the lamination of the electrolyte layer and the electrolyte layer, and the electrode containing the electrolyte is produced.

Here, the contact resistance between a metal generally used as an electrode terminal (for example, aluminum, copper, etc.) and the material constituting the positive electrode side conductive layer 33a is the metal between the metal and a metal such as stainless steel (SUS). It is much smaller than the contact resistance. For example, the contact resistance at the surface contact portion between aluminum and SUS is about 10 to 1000 mΩ · cm ² , whereas the contact resistance at the surface contact portion between aluminum and a general negative electrode active material layer is 1 to 10 mΩ · cm 2. It is about ² . Although the mechanism by which the contact resistance is remarkably different in this way is not completely clear, the conductive material improves conductivity by breaking and biting the oxide film formed on the current collector, or the planar metal plates ( In the electrode terminal plate-current collector), it is difficult to make complete contact at the nano level. On the other hand, in the conductive layer containing the electrode terminal plate-conductive material, there are nano-level irregularities on the conductive layer side. It is estimated that the contact area is improved. However, such a mechanism is merely based on estimation, and even if the contact resistance is actually changed by another mechanism, the technical scope of the present invention is not affected at all. In addition, the value of the contact resistance mentioned above can be measured by the method of measuring the resistance between the said contact bodies with an alternating current impedance measuring apparatus, for example in the state which applied the constant load with the fixed areas between the contact bodies. However, other techniques can also be employed if accurate values are obtained.

  Therefore, in the bipolar battery 10 of the form shown in FIG. 1, since the positive electrode side conductive layer 33a is formed in the outermost layer on the positive electrode side, an electrode terminal (positive electrode terminal) similar to the conventional one is provided on the positive electrode side conductive layer 33a. The contact resistance in the case of bonding can be significantly reduced as compared with the conventional case. As a result, the internal resistance of the battery can be reduced, and a battery excellent in output characteristics under high output conditions can be provided.

  Further, in the conventional bipolar battery, only one of the positive electrode active material layer and the negative electrode active material layer is formed in the outermost layer current collector, and the current collectors at both ends of the battery element are both exposed. Was. For this reason, it is necessary to prepare the outermost electrode separately from the normal bipolar electrode disposed outside the outermost layer, and as the number of parts increases and the manufacturing process becomes complicated, the manufacturing cost must increase. There was a problem that I could not. On the other hand, in the form shown in FIG. 1, the structure of the positive electrode side conductive layer 33a is the same as that of the negative electrode active material layer 15 (however, as described above, the electrolyte is not included). That is, in this embodiment, the same electrode as the normal bipolar electrode 20 is disposed in the outermost layer on the positive electrode side. Therefore, according to the bipolar battery 10 of the present embodiment, the number of parts at the time of manufacture can be reduced, the manufacturing process can be simplified, and the manufacturing cost can be expected to be reduced.

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

(Current collector)
The current collector that can be used in the present embodiment is not particularly limited, and a conventionally known current collector can be used. For example, an aluminum foil, a SUS foil, a clad material of nickel and aluminum, a clad material of copper and aluminum, or a plating material of a combination of these metals can be preferably used. Moreover, the foil by which aluminum is coat | covered on the metal surface may be sufficient. Moreover, you may use the electrical power collector which bonded 2 or more metal foil depending on the case. Although depending on the type of active material, it is preferable to use a SUS foil as a current collector from the viewpoint of being able to withstand the potential of each electrode and being able to be thinned with a single foil. Furthermore, since the surface contact resistance between SUS and aluminum is large as described above, when aluminum is used as the constituent material of the positive electrode terminal, the effect of the present invention is even more remarkable when the SUS foil is used as a current collector. Can be demonstrated.

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

(Positive electrode active material layer)
The positive electrode includes a positive electrode active material. In addition, a conductive additive, a binder, an electrolyte (for example, a polymer gel electrolyte) and the like can be included.

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. These may be used alone or in combination of two or more.

  The particle diameter of the positive electrode active material is not limited as long as the positive electrode material can be formed into a paste by spray coating and the like, but the electrolyte is not a solid solution in order to reduce the electrode resistance of the bipolar battery. 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.

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

  Examples of the binder include polyvinylidene fluoride (PVdF) and a synthetic rubber binder.

  The polymer gel electrolyte is a solid polymer electrolyte having ion conductivity containing an electrolytic solution usually used in a lithium ion battery, and further, in a polymer skeleton having no lithium ion conductivity, The thing holding the same electrolyte solution is also included.

Examples of the electrolyte contained in the polymer gel electrolyte (electrolytic salt and solvent) may be any one usually used in a lithium ion battery, 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 among 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 2-dimethoxyethane and 1,2-dibutoxyethane; lactones such as γ-butyrolactone; nitriles such as acetonitrile; esters such as methyl propionate; amides such as dimethylformamide; Those using an organic solvent 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.

  Examples of the polymer having no lithium ion conductivity used for the polymer gel electrolyte include polyvinylidene fluoride (PVDF), polyvinyl chloride (PVC), polyacrylonitrile (PAN), and polymethyl methacrylate (PMMA). . However, it is not necessarily limited to these. PAN, PMMA, and the like are in a class that has almost no ionic conductivity. Therefore, the polymer can have the above ionic conductivity, but here, it is used 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. In this embodiment, the electrolyte solution, lithium salt, and polymer are mixed to prepare a pregel solution, and the electrode is impregnated.

  The amount of positive electrode active material, conductive additive, binder, and electrolyte in the positive electrode should be determined in consideration of the intended use of the battery (emphasis on output, energy, etc.), ion conductivity, and the like. For example, if the amount of the electrolyte in the positive electrode 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, when the amount of the electrolyte in the positive electrode is too large, the energy density of the battery is lowered. Therefore, it is preferable to determine the electrolytic mass that meets the purpose in consideration of these factors.

  The thickness of the positive electrode is not particularly limited, and should be determined in consideration of the intended use of the battery (emphasis on output, emphasis on energy, etc.), ion conductivity, etc. A typical positive electrode active material layer has a thickness of about 1 to 100 μm.

(Negative electrode active material layer)
The negative electrode includes a negative electrode active material. In addition, a conductive additive, a binder, an electrolyte (polymer gel electrolyte), and the like can be included. Since the contents other than the type of the negative electrode active material are basically the same as the contents described in the section “Positive electrode”, the description 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 this embodiment, the positive electrode active material layer uses lithium-transition metal composite oxide as the positive electrode active material, and the negative electrode active material layer uses carbon or lithium-transition metal composite oxide as the negative electrode active material. Is used. This is because a battery having excellent capacity and output characteristics can be configured.

(Electrolyte layer)
The electrolyte layer 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 the present embodiment is a polymer gel electrolyte, and is used as a polymer gel electrolyte by chemical crosslinking or physical crosslinking after impregnating a separator as a substrate with a pregel solution.

  Such a polymer gel electrolyte is an all-solid polymer electrolyte having ion conductivity such as polyethylene oxide (PEO) containing an electrolyte solution usually used in a lithium ion battery. In the polymer gel electrolyte, a polymer electrolyte having a similar electrolyte solution held in a polymer skeleton having no lithium ion conductivity such as (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, description thereof is omitted here. The ratio of the polymer constituting the polymer gel electrolyte to the electrolyte solution is wide. When 100% of the polymer is an all solid polymer electrolyte and 100% of the electrolyte solution 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 and / or the negative electrode as described above in addition to the polymer electrolyte constituting the battery, but uses a polymer electrolyte that differs depending on the polymer electrolyte, positive electrode, and negative electrode constituting the battery. Alternatively, the same polymer electrolyte may be used, or different polymer electrolytes may be used depending on the layer.

  The thickness of the electrolyte layer constituting the battery is not particularly limited. However, in order to obtain a compact bipolar battery, it is preferable to make it as thin as possible as long as the function as an electrolyte can be secured. The thickness of a general electrolyte layer is about 1 to 100 μm. However, the shape of the electrolyte can be easily formed so as to cover the upper surface and the outer peripheral surface of the electrode (positive electrode or negative electrode) by taking advantage of the characteristics of the manufacturing method. It is not always necessary to have a substantially constant thickness.

  A solid electrolyte can also be used for the electrolyte layer. By using a solid electrolyte as the electrolyte, it is possible to prevent leakage, preventing a liquid junction, which is a problem peculiar to bipolar batteries, and providing a highly reliable battery. Moreover, since there is no liquid leakage, the structure of the seal part 31 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.

(Separator)
As the separator, both a microporous membrane separator and a nonwoven fabric separator can be used.

  As the microporous membrane separator, for example, a porous sheet made of a polymer that absorbs and holds an electrolyte can be used. Examples of the polymer material include polyethylene (PE), polypropylene (PP), a laminate having a three-layer structure of PP / PE / PP, and polyimide.

  As the nonwoven fabric separator, for example, a sheet in which fibers are entangled can be used. In addition, a spunbond obtained by fusing fibers together by heating can also be used. In other words, it may be in the form of a sheet formed by arranging fibers in a web (thin cotton) shape or mat shape by an appropriate method, and joining them using an appropriate adhesive or the fusing force of the fibers themselves. The fiber to be used is not particularly limited, and conventionally known fibers such as cotton, rayon, acetate, nylon, polyester, polypropylene, polyethylene such as polyethylene, polyimide, and aramid can be used. These are used alone or in combination depending on the purpose of use (such as mechanical strength required for the electrolyte layer 17).

(Seal part)
It is preferable that the seal part 31 penetrates the separator or covers the entire side surface of the separator. This is because the cell layer 19 and the outside air can be reliably blocked from contacting each other through the separator.

  The sealing portion 31 can be formed of a sealing resin. As the sealing resin, a rubber-based resin that is in close contact with the current collector 11 by being pressurized and deformed, or a current collector that is heat-pressed and thermally fused. Resins that can be heat-sealed, such as olefin resins that are in close contact with the body 11, can be suitably used.

  In the form shown in FIG. 1, a rubber-based resin is used as the sealing resin. In the rubber-based seal portion 31 using the rubber-based resin, the contact between the unit cell layer 19 and the outside air can be blocked using the elasticity of the rubber-based resin. Further, even in an environment in which stress due to vibration or impact is repeatedly applied to the bipolar battery 10, the rubber seal 31 is easily twisted or deformed following the twist or deformation of the bipolar battery 10. The sealing effect can be maintained. Furthermore, there is no need to perform heat fusion treatment, which is advantageous in that the battery manufacturing process is simplified. The rubber resin is not particularly limited, but is preferably a rubber resin selected from the group consisting of silicon rubber, fluorine rubber, olefin rubber, and nitrile rubber. These rubber-based resins are excellent in sealing properties, alkali resistance, chemical resistance, durability / weather resistance, heat resistance, etc., and should be maintained for a long period of time without degrading their excellent performance and quality even in the use environment. Can do. For this reason, the interruption of the contact between the unit cell layer 19 and the outside air, that is, the sealing of the unit cell layer 19 can be effectively prevented for a long time. However, it is not limited to the exemplified rubber-based resin.

  In addition, the seal part 31 can also be comprised from the three-layer film which pinched | interposed the non-fusion layer with the fusion | melting layer. Further, the size of the seal portion 31 is not limited to a size that does not protrude in the surface direction from the end portion of the current collector 11 as shown in FIG. 1, and is a size that protrudes in the surface direction from the end portion of the current collector 11. You may have. According to such a configuration, an internal short circuit due to contact between the outer peripheral edges of the current collector 11 can be reliably prevented.

  The bipolar battery of this embodiment can be manufactured by appropriately referring to conventionally known knowledge without using a special technique. In particular, as a method for forming a conductive layer on a current collector, a method used for forming an active material layer on a current collector when a normal bipolar electrode is manufactured can be similarly used.

(Second and third embodiments)
FIG. 2 is a cross-sectional view showing the bipolar battery of the second embodiment, and FIG. 3 is a cross-sectional view showing the bipolar battery of the third embodiment. In addition, the same code | symbol is attached | subjected to the member which is common in the member in 1st Embodiment, and the description is partially abbreviate | omitted.

  In the second and third embodiments, in addition to the positive electrode side conductive layer 33a, the negative electrode side conductive layer 33b is formed on the surface of the negative electrode side outermost layer current collector 11b facing the electrolyte layer 17b. This is different from the first embodiment. In the second embodiment shown in FIG. 2, the configuration (composition, thickness, etc.) of the negative electrode side conductive layer 33b is the same as that of the positive electrode side conductive layer 33a (that is, the same as that of the negative electrode active material layer 15). As described above, the electrolyte is not included). On the other hand, in the third embodiment shown in FIG. 3, the configuration of the negative electrode side conductive layer 33b is the same as that of the positive electrode active material layer 13 (however, as described above, the electrolyte is not included). In these points, the second and third embodiments are different.

  In the second and third embodiments, the conductive layers (33a, 33b) are formed on both the positive electrode side outermost layer current collector 11a and the negative electrode side outermost layer current collector 11b. Therefore, the contact resistance between the outermost layer current collector 11b on the negative electrode side and the negative electrode terminal is also reduced, and finally the internal resistance of the battery can be further reduced. As a result, a bipolar battery having excellent output characteristics can be provided.

  In the second embodiment, the composition of the negative electrode-side conductive layer 33 b is the same as that of the negative electrode active material layer 15. Here, in general, the negative electrode active material layer 15 containing a highly conductive active material is superior in conductivity to the positive electrode active material layer 13. For this reason, according to 2nd Embodiment, the contact resistance in the negative electrode side can be reduced further like the positive electrode side. In the second embodiment, as shown in FIG. 2, the bipolar electrode located in the outermost layer on the negative electrode side is different from the normal bipolar electrode 20, and the negative electrode active material layer 15 is formed on both surfaces of the current collector 11. Is formed. However, the function of the negative electrode side conductive layer 33b is only to reduce the contact resistance between the negative electrode terminal 27 and the negative electrode side outermost layer current collector 11b, and does not function as a negative electrode active material layer. Absent.

  On the other hand, in the third embodiment, the composition of the negative electrode side conductive layer 33 b is the same as that of the positive electrode active material layer 13. Therefore, although the contact resistance reduction effect is somewhat inferior to the second embodiment, the contact resistance can be reduced as compared with the first embodiment in which the negative electrode side conductive layer 33b is not disposed. In the third embodiment, as shown in FIG. 3, the bipolar electrode located in the outermost layer on the negative electrode side has the same configuration as that of the normal bipolar electrode 20. Therefore, since only one type of bipolar electrode is prepared when manufacturing the bipolar battery 10 of the third embodiment, a significant reduction in manufacturing cost can be expected.

  The preferred embodiments of the bipolar battery of the present invention have been described above by taking three representative embodiments as examples. However, the present invention is not limited to the above-described embodiments, and other embodiments can also be adopted. For example, unlike the first embodiment, the composition of the positive electrode side conductive layer 33 a may be the same as the composition of the positive electrode active material layer 13. The composition of the conductive layers (33a, 33b) may be different from the composition of the active material layers (13, 15). The material constituting the conductive layers (33a, 33b) is not particularly limited as long as it includes a conductive material. For example, in addition to the same material as the active material layer (13, 15) described above, a carbon material, a conductive polymer material, a conductive paste, a conductive epoxy material, and the like can be given. The conductive layers (33a, 33b) can be formed, for example, by binding a conductive material (metal fine particles, conductive polymer, carbon) or the like with a binder (polymer material or rubber material). However, it is not limited only to these forms, and other materials can also be employed as long as the effects of the present invention can be exhibited.

  Furthermore, in the first to third embodiments, the conductive layers (33a, 33b) are formed in the same size as the active material layers (13, 15) in the normal bipolar electrode 20. According to such a form, since a conductive layer can be formed by the same method and equipment as manufacturing a bipolar electrode, it is preferable from the viewpoint of manufacturing cost. However, it is not limited to such a form, and it is needless to say that a conductive layer having a size different from the size of the active material layer may be formed.

(Fourth embodiment)
FIG. 4 is a cross-sectional view showing the bipolar battery of this embodiment.

  In the present embodiment, the bipolar battery 10 of the second embodiment is sealed in an exterior material to constitute a sheet-like bipolar battery.

  In the bipolar battery 10 shown in FIG. 4, an aluminum plate 25 that is a positive electrode terminal is bonded to the entire surface of the positive electrode side conductive layer 33 a located on the positive electrode side outermost layer of the battery element 21, and the contact surface is in one direction. It is extended toward. On the other hand, a copper plate 27 serving as a negative electrode terminal is bonded to the entire surface of the negative electrode side conductive layer 33b located in the negative electrode side outermost layer of the battery element 21, and the contact surface is unidirectional (opposite to the extension direction of the positive electrode terminal). Direction). And the battery element 21 is sealed in the laminate sheet 29 which is an exterior material so that these positive electrode terminals and negative electrode terminals may lead out outside. By sealing in the laminate sheet 29, the impact from the outside at the time of use can be relieved and environmental degradation can be prevented.

  In the fourth embodiment, the aluminum plate 25 as the positive electrode terminal and the negative electrode terminal are formed on the entire surface of the conductive layers (33a, 33b) located on the outermost layers on both sides of the battery element 21 of the bipolar battery of the first embodiment. A certain copper plate 27 is joined. For this reason, the bipolar battery 10 in which the effects described in the column of the second embodiment are obtained and the internal resistance is reduced can be provided.

  The structure of the electrode terminal and the exterior material used in the bipolar battery 10 of the present embodiment is not particularly limited, and a known material used in a general lithium ion secondary battery can be used. Below, the structure of the electrode terminal and exterior material which can be used for the sheet-like bipolar battery 10 of this invention is demonstrated for reference.

(Electrode terminal)
The material for the electrode terminals (the positive electrode terminal and the negative electrode terminal) is not particularly limited, and known materials conventionally used as electrode terminals for bipolar batteries can be used. Examples thereof include aluminum, copper, titanium, nickel, stainless steel (SUS), and alloys thereof. In addition, the same material may be used for a positive electrode terminal and a negative electrode terminal, and a different material may be used. Further, as in the first embodiment, the electrode terminal at the electrode where the conductive layer (33a or 33b) is not provided may be an extension of the outermost layer current collector (11a or 11b), or separately prepared. Then, it may be connected to the outermost layer current collector.

  As described above, the surface contact resistance between SUS and aluminum is relatively large. Therefore, when SUS is used as the constituent material of the current collector of the bipolar electrode, it is preferable to use aluminum as the constituent material of the electrode terminal because the operational effects of the present invention can be expressed more significantly.

(Exterior material)
The exterior material is not particularly limited, and a conventionally known exterior material can be used. Easily cool the heat from the heat source of the car or the self-heating of the battery due to high load, and efficiently transfer the heat from the car's heat source at the time of cold start, and can quickly heat the inside of the battery to the battery operating temperature In this respect, preferably, a polymer-metal composite laminate sheet having excellent thermal conductivity can be used. Further, by placing the inside of the laminate at a pressure lower than the atmospheric pressure, it becomes possible to make contact between the battery elements or between the battery elements and the electrode terminals at atmospheric pressure, and further to reduce the contact resistance. .

  The sheet-like bipolar battery of this embodiment can be manufactured by appropriately referring to conventionally known knowledge without using a special technique.

(Fifth and sixth embodiments)
FIG. 5 is a cross-sectional view showing the bipolar battery of the fifth embodiment, and FIG. 6 is a cross-sectional view showing the bipolar battery of the sixth embodiment. In addition, the same code | symbol is attached | subjected to the member which is common in the member in 4th Embodiment, and the description is partially abbreviate | omitted.

  In the fifth and sixth embodiments, the electrode terminals are connected to the bipolar batteries of the first and third embodiments, respectively, and sealed in a laminate sheet to constitute a sheet-like bipolar battery. This is different from the fourth embodiment.

  However, in any of the fifth and sixth embodiments, at least one of the positive electrode side and the negative electrode side (only the positive electrode side in the fifth embodiment and both the positive electrode side and the negative electrode side in the sixth embodiment) Conductive layers (33a, 33b) are interposed between the electric body and the electrode terminals. For this reason, as in the fourth embodiment, the contact resistance between the outermost layer current collector and the electrode terminal can be reduced. As a result, these embodiments can also provide a bipolar battery with reduced internal resistance and excellent output characteristics.

(Seventh embodiment)
FIG. 7 is a cross-sectional view showing the battery module of the seventh embodiment.

  As shown in FIG. 7, the battery module 40 of the seventh embodiment includes a plurality (four in the illustrated example) of the bipolar battery 10 of the first embodiment and both sides along the direction in which the bipolar electrode 20 is laminated. It has a pair of conductive holding plates 50 and 60 that sandwich and hold a plurality of bipolar batteries 10 and electrically connect the bipolar batteries 10 to each other. In the plurality of bipolar batteries 10, the battery element 21 is directly sandwiched between a pair of holding plates 50 and 60. Here, “directly” means that there is no intervening packaging material that encloses and seals the entire battery element 21.

  In the seventh embodiment, the four bipolar batteries 10 are stacked in the direction in which the bipolar electrodes 20 are stacked (vertical direction in FIG. 7) and are electrically connected in series. This electrical connection form is referred to as “4 series”. The battery module 40 further includes a fastening member 70 that maintains a state in which a plurality of bipolar batteries 10 are sandwiched between a pair of holding plates (50, 60), and a top plate via a holding plate 50 shown on the upper side in FIG. The positive electrode terminal 81 electrically connected to the conductive layer 33a disposed on the positive electrode side of the bipolar battery 10 and the negative electrode of the lowest bipolar battery 10 through the holding plate 60 shown on the lower side in FIG. And a negative electrode terminal 82 electrically connected to the side outermost layer current collector 11b.

  As shown in FIG. 7, in the seventh embodiment, the upper and lower holding plates (50, 60) are both formed from conductive plates (51, 61) having conductivity. The conductive plates (51, 61) are made of, for example, aluminum or SUS. Bolt holes (51 a, 61 a) are formed in the upper and lower holding plates (50, 60) in order to insert the through bolts 71. By fastening the nut 72 to the through bolt 71 inserted into each bolt hole (51a, 61a), the state where the plurality of bipolar batteries 10 are sandwiched by the upper and lower holding plates (50, 60) is maintained. Since the upper and lower holding plates (50, 60) are both conductive, the through bolt 71 and the nut 72 are made of an electrically insulating material. The through bolt 71 and the nut 72 constitute a fastening member 70 that maintains a state in which the plurality of bipolar batteries 10 are sandwiched between the pair of holding plates (50, 60).

  In the seventh embodiment, each of the four bipolar batteries 10, and the uppermost bipolar battery 10 and the conductive plate 51, which is the upper holding plate 50, are secured to each other through the conductive layer 33a. . Here, consider a case where such a conductive layer 33a does not exist. Since the current collector 11 is generally formed from a metal foil, the surface of the current collector 11 has an uneven shape when viewed microscopically. Therefore, when the bipolar batteries 10 are connected in series by surface contact between the outermost current collectors without using the conductive layer 33a, the contact resistance between the bipolar batteries 10 may increase. The same applies to contact portions between the conductive plates (51, 61) that are the upper and lower holding plates (50, 60) and the outermost layer current collector.

  On the other hand, in the battery module of the seventh embodiment, the conduction between the bipolar batteries 10 and the conduction between the conductive plate 51 as the upper holding plate 50 and the uppermost bipolar battery 10 are the conductive layer 33a. Secured through. Thereby, the contact resistance of each conduction | electrical_connection part can be reduced, the battery module which is excellent in an output characteristic with small internal resistance can be provided. In the embodiment shown in FIG. 7, the conduction between the lowest bipolar battery 10 and the conductive plate 61 which is the lower holding plate 60 is the conductive plate 61 made of SUS foil and metal constituting the outermost current collector 11b. It is secured by surface contact with. However, it is not limited only to such a form, From a viewpoint mentioned above, it is preferable to provide a conductive layer between the lowest bipolar battery 10 and the lower holding plate 60 (conductive plate 61). The specific form of the conductive layer provided at this time is not described here because the above-described form can be similarly adopted.

  In the seventh embodiment, since the bipolar battery 10 is provided with the seal portion 31 that blocks the contact between the single cell layer 19 and the outside air, there is no need to seal the battery element 21 with an exterior material. The bipolar battery 10 is directly sandwiched between a pair of holding plates (50, 60). When the battery module 40 is formed, a series of operations for forming the battery module 40 using the bipolar battery 10 can be simplified by eliminating the need to seal the individual battery elements 21 with an exterior material. it can. Further, the plurality of bipolar batteries 10 are electrically connected only by sandwiching and holding the plurality of bipolar batteries 10 by the upper and lower holding plates (50, 60). Further, when electrically connecting a plurality of bipolar batteries 10, it is not necessary to join the current extraction terminals by welding or to connect them via a connecting member such as a bus bar. Also from this viewpoint, a series of operations for forming the battery module 40 can be simplified. Since the bipolar batteries 10 are directly connected to each other without interposing a current extracting terminal, the output of the battery module 40 can be increased. Since the exterior material and the terminal for taking out the current are not necessary, the volume of the battery module 11 can be reduced accordingly. In addition, since the upper and lower holding plates (50, 60) are both conductive, it is possible to take out current simply by sandwiching and holding a plurality of bipolar batteries 10 and simplify the structure for taking out current. it can. Thus, the battery module 40 has a structure that takes advantage of the bipolar battery 10 that current flows in the stacking direction in the battery element 21, and the battery module 40 using the bipolar battery 10 can be easily formed. It will be something.

  Furthermore, since the plurality of bipolar batteries 10 are electrically connected in series, it is possible to easily meet the demand for output simply by changing the number of series connection. In addition, when a part of the individual bipolar batteries 10 constituting the battery module 40 does not function, only the bipolar battery 10 that does not function can be obtained without replacing the entire battery module 40 with another battery module. Since the function as the battery module 40 can be restored simply by replacing the battery with another bipolar battery 10, the function can be restored at a low cost.

  Although illustration is omitted, it goes without saying that the battery module may be configured using bipolar batteries as in the second and third embodiments in addition to the bipolar battery 10 of the first embodiment. Even in such a configuration, the contact resistance between the conductive parts between the bipolar batteries and the conductive part between the uppermost or lowermost bipolar battery and the holding plate is reduced, and the battery module has low internal resistance and excellent output characteristics. Can be provided.

(Eighth and ninth embodiments)
FIG. 8 is a cross-sectional view showing the battery module of the eighth embodiment, and FIG. 9 is a cross-sectional view showing the battery module of the ninth embodiment. In addition, the same code | symbol is attached | subjected to the member which is common in the member in 7th Embodiment, and the description is partially abbreviate | omitted.

  The eighth and ninth embodiments differ from the seventh embodiment in that the electrical connection mode of the plurality of bipolar batteries 10 is modified.

  As shown in FIG. 8, in the battery module 41 of the eighth embodiment, two bipolar batteries 10 of the first embodiment are arranged in a direction orthogonal to the stacking direction of the bipolar electrodes 20. Further, the two bipolar batteries 10 are arranged so that the electric polarities are the same (the upper side in the figure is the positive electrode side and the lower side is the negative electrode side), and the two bipolar batteries 10 are electrically connected via the upper and lower holding plates (50, 60). Are connected in parallel. This electrical connection form is referred to as “two parallel”.

  In the eighth embodiment, since the plurality of bipolar batteries 10 are electrically connected in parallel, it is possible to easily meet the capacity-related requirements simply by changing the number of parallel connections. .

  As shown in FIG. 9, the battery module 42 of the ninth embodiment includes two battery groups in which two bipolar batteries 10 of the first embodiment are stacked in the vertical direction and electrically connected in series. They are arranged in a direction perpendicular to the stacking direction of the mold electrodes 20. Further, the two battery groups are arranged so that the electric polarities are the same (the upper side in the figure is the positive electrode side and the lower side is the negative electrode side), and are electrically in parallel via the upper and lower holding plates (50, 60). It is connected to the. This electrical connection form is referred to as “2 parallel × 2 series”.

  In the ninth embodiment, since a plurality of bipolar batteries 10 are electrically connected in series and parallel, only by changing the number connected in series and the number connected in parallel, the demand for output and capacity can be met. It can respond easily.

(10th Embodiment)
FIG. 10 is a cross-sectional view showing the battery module of the tenth embodiment. In addition, the same code | symbol is attached | subjected to the member which is common in the member in 7th-9th embodiment, and the description is partially omitted.

  The tenth embodiment is the same as the eighth embodiment except that the periphery of the bipolar battery 10 is filled with a filler 90.

  The battery module 43 of the tenth embodiment includes a filler 90 that is filled around the bipolar battery 10. A known potting material can be used for the filler 90. The potting material is formed from an olefin resin, a silicon resin, an epoxy resin, or the like. By filling the periphery of the bipolar battery 10 with the filler 90, the bipolar battery 10 is prevented from being displaced, and the battery module 43 is suitable for application to an in-vehicle battery to which vehicle vibration is applied. Furthermore, since moisture in the atmosphere is blocked by the filler 90, the battery module 43 that operates stably over a long period of time can be provided in combination with the action of the seal portion 31 of the bipolar battery 10. That is, by filling the filler 90 in this way, the battery module 43 with improved vibration resistance and waterproofness can be provided.

(Eleventh embodiment)
In the eleventh embodiment, an assembled battery is configured (not shown).

  The assembled battery is configured by electrically connecting a plurality of the battery modules of the seventh to tenth embodiments described above in parallel and / or in series. By paralleling and / or serializing, the capacity and voltage can be freely adjusted.

  For example, a plurality of battery modules (40 to 43) described above are stacked and stored in an assembled battery case, and the battery modules can be connected in parallel. In addition, each of the positive terminals 81 can be connected via a conductive bar, and each of the negative terminals 82 can be connected via a conductive bar.

  According to the eleventh embodiment, a battery with a high capacity and a high output can be obtained by connecting a plurality of battery modules to form an assembled battery. In addition, each of the battery modules using the bipolar battery 10 has a structure that takes advantage of the bipolar battery 10 that the current flows in the stacking direction in the battery element 21 and can be easily formed. Through this, it becomes easy to form an assembled battery in which a plurality of battery modules are electrically connected. Moreover, since the battery module of this invention is excellent in an output characteristic, an assembled battery is also excellent in an output characteristic.

  Depending on the required capacity and voltage, an assembled battery in which all of a plurality of battery modules are connected in parallel or an assembled battery in which series connection and parallel connection are combined can be used. In addition, if a part of the individual battery modules that make up the assembled battery stops functioning as a result of the battery assembly, the battery module can no longer function without replacing the entire assembled battery with another assembled battery. Since the function as the assembled battery can be recovered simply by replacing only the battery module with another battery module, the function can be recovered at a low cost.

(Twelfth embodiment)
In the twelfth embodiment, the assembled battery of the eleventh embodiment is mounted as a motor driving power source to constitute a vehicle. Examples of vehicles that use the assembled battery as a power source for motors include vehicles that drive wheels by a motor, such as fully electric vehicles that do not use gasoline, hybrid vehicles such as series hybrid vehicles and parallel hybrid vehicles, and fuel cell vehicles. It is done.

  For reference, FIG. 11 shows a schematic diagram of an automobile 200 on which the assembled battery 100 is mounted. The assembled battery 100 mounted on the automobile 200 has the characteristics as described above. For this reason, the automobile 200 equipped with the assembled battery 100 has excellent output characteristics and can provide sufficient output even under high output conditions.

  As described above, some preferred embodiments of the present invention have been described. However, the present invention is not limited to the above embodiments, and various modifications, omissions, and additions can be made by those skilled in the art. .

  The effects of the present invention will be described using the following examples and comparative examples. However, the technical scope of the present invention is not limited only to the following examples.

<Example 1>
<Production of electrode>
Spinel-type lithium manganate (average particle size: 5 μm) (85% by mass) as a positive electrode active material, acetylene black (5% by mass) as a conductive additive, and polyvinylidene fluoride (PVdF) (10% by mass) as a binder An appropriate amount of N-methyl-2-pyrrolidone (NMP), which is a slurry viscosity adjusting solvent, was added to the solid content consisting of) to prepare a positive electrode active material slurry.

  On the other hand, hard carbon (average particle size: 10 μm) (85% by mass) as a negative electrode active material, acetylene black (5% by mass) as a conductive additive, and polyvinylidene fluoride (PVdF) (10% by mass) as a binder An appropriate amount of N-methyl-2-pyrrolidone (NMP), which is a slurry viscosity adjusting solvent, was added to the solid content consisting of to prepare a negative electrode active material slurry.

  The positive electrode active material slurry prepared above is applied to one surface of a SUS foil (thickness: 20 μm) prepared as a current collector, and the negative electrode active material slurry prepared above is also applied to the other surface and dried. Thus, 12 bipolar electrodes were produced. Moreover, the negative electrode active material slurry prepared above was applied to one side of a SUS foil similar to the above, and dried to produce one electrode having a negative electrode active material layer formed on one side and the other side exposed. These electrodes were cut into a size of 130 mm × 80 mm, and the peripheral portion of the active material layer was peeled off with a width of 10 mm to expose the SUS foil.

<Preparation of gel electrolyte layer>
LiBETI, a lithium salt, is dissolved in an equal volume mixture of propylene carbonate (PC) and ethylene carbonate (EC) to a concentration of 1M, and an appropriate amount of benzyl dimethyl ketal (BDK), a photopolymerization initiator, is added. Thus, an electrolytic solution was prepared. On the other hand, a solution (5% by mass) of a copolymer (average molecular weight: 7500 to 9000) of polyethylene oxide (PEO) and polypropylene oxide (PPO) which is a precursor of an ion conductive polymer (matrix polymer) The prepared electrolyte solution (95 mass%) was added to prepare a pregel solution.

  The pregel solution prepared above is immersed in a polypropylene nonwoven fabric (thickness: 50 μm) as a separator and sandwiched between two quartz glass substrates, and then the precursor is crosslinked by irradiating with ultraviolet rays for 15 minutes. Thus, 12 gel polymer electrolyte layers were produced.

<Production of bipolar battery>
The bipolar electrode prepared above and the gel polymer electrolyte layer are alternately laminated so that the electric polarity of the bipolar electrode is the same, and only the negative electrode active material layer is provided on one side of the current collector on the bottom surface. The electrode formed with was arranged so that the current collector was exposed. When laminating the bipolar electrode and the gel polymer electrolyte layer, the non-fused layer is fused in two layers so as to surround the single cell layer (positive electrode active material layer + gel polymer electrolyte layer + negative electrode active material layer). A frame-type three-layer film sandwiched between the layers was disposed as a seal portion. After the lamination, the seal part was hot pressed at 180 ° C. for several seconds to complete a bipolar battery (see FIG. 1).

<Example 2>
An electrode having a negative electrode active material layer formed on both sides of the current collector is prepared instead of the exposed electrode on one side of the current collector, and the other surface is the bottom surface. A bipolar battery was fabricated in the same manner as in Example 1 except that the bipolar electrode and the electrolyte layer were laminated so as to be disposed in the same manner as in Example 1 (see FIG. 2).

<Example 3>
Only the negative electrode active material layer is formed on one side of the current collector, the other side is replaced with an exposed electrode, and another electrode identical to the other bipolar electrode is prepared, with the negative electrode active material layer on the bottom surface A bipolar battery was fabricated in the same manner as in Example 1 except that 13 bipolar electrodes and an electrolyte layer were laminated so as to be exposed (see FIG. 3).

<Comparative example>
Instead of the bipolar electrode disposed on the top surface, a positive electrode active material layer is formed on one side of the current collector, and an electrode is produced on the other surface so that the current collector is exposed on the top surface. A conventional bipolar battery was produced in the same manner as in Example 1 except that the electrodes were arranged.

<Measurement of internal resistance>
Electrode terminals were connected to the positive electrode side and the negative electrode side of the bipolar batteries prepared in Examples 1 to 3 and the comparative example, respectively, and the internal resistance of each bipolar battery was measured. At this time, an aluminum foil (thickness: 150 μm) was used as the positive electrode terminal, and a copper foil (thickness: 150 μm) was used as the negative electrode terminal. The measurement of the internal resistance, by a method of measuring the AC impedance measuring device the resistance between the contact body contact bodies while applying a constant load (1gf / cm ²⁾ at a certain area (100 cm ²⁾ went. The measurement results are shown in Table 1 below. In Table 1, the value of the internal resistance is shown as a relative value when the internal resistance of the bipolar battery of the comparative example is 10.

  The comparison between the example and the comparative example shows that according to the present invention, the internal resistance in the bipolar battery can be reduced by forming the conductive layer. Moreover, the comparison between Example 1 and Examples 2 and 3 shows that the internal resistance can be further reduced by forming conductive layers on both the positive electrode side and the negative electrode side of the bipolar battery. Furthermore, the comparison between Example 2 and Example 3 shows that the internal resistance can be further reduced by adopting the same composition as the negative electrode active material layer as the composition of the conductive layer.

It is sectional drawing which shows the bipolar battery of 1st Embodiment. It is sectional drawing which shows the bipolar battery of 2nd Embodiment. It is sectional drawing which shows the bipolar battery of 3rd Embodiment. It is sectional drawing which shows the sheet-like bipolar battery of 4th Embodiment. It is sectional drawing which shows the sheet-like bipolar battery of 5th Embodiment. It is sectional drawing which shows the sheet-like bipolar battery of 6th Embodiment. It is sectional drawing which shows the battery module of 7th Embodiment. It is sectional drawing which shows the battery module of 8th Embodiment. It is sectional drawing which shows the battery module of 9th Embodiment. It is sectional drawing which shows the battery module of 10th Embodiment. It is the schematic which shows the motor vehicle of 12th Embodiment carrying the assembled battery of 11th Embodiment.

Explanation of symbols

10 Bipolar battery,
11 Current collector,
11a Positive electrode side outermost layer current collector,
11b The negative electrode side outermost layer current collector,
13 positive electrode active material layer,
15 negative electrode active material layer,
17 electrolyte layer,
17a electrolyte layer located in the outermost layer on the positive electrode side,
17b an electrolyte layer located in the outermost layer on the negative electrode side;
19 cell layer,
20 bipolar electrodes,
21 battery elements,
23 laminates,
25 positive terminal,
27 negative terminal,
29 Laminate sheet,
31 seal part,
33a, 33b conductive layer,
40-43 battery module,
50, 60 holding plate,
51, 61 conductive plate,
51a, 61a bolt holes,
70 fastening members,
71 through bolts,
72 nuts,
81 positive terminal,
82 negative terminal,
90 filler,
100 battery packs,
200 Automobile (vehicle).

Claims (6)

A laminate in which a plurality of bipolar electrodes each having a positive electrode active material layer formed on one surface of the current collector and a negative electrode active material layer formed on the other surface are stacked via an electrolyte layer;
A seal portion disposed around each of the unit cell layers formed by laminating the positive electrode active material layer, the electrolyte layer, and the negative electrode active material layer, and blocking the contact between the unit cell layer and outside air;
A bipolar battery having a battery element comprising:
In at least one of the positive electrode side outermost layer current collector and the negative electrode side outermost layer current collector, a conductive layer containing a conductive material and a binder is formed on the surface opposite to the side facing the electrolyte layer. A bipolar battery that is characterized.   The bipolar battery according to claim 1, wherein the conductive layer is formed on both the positive electrode side outermost layer current collector and the negative electrode side outermost layer current collector.   The bipolar battery according to claim 1 or 2, wherein a material constituting the conductive layer is the same as a material constituting the negative electrode active material layer.   The material constituting the conductive layer disposed on the positive electrode side outermost current collector is the same as the material constituting the negative electrode active material layer, and the conductive layer disposed on the negative electrode side outermost current collector is The bipolar battery according to claim 2, wherein a constituent material is the same as a constituent material of the positive electrode active material layer. The positive terminal on the conductive layer of the positive electrode side of the battery element is further connected directly, the negative terminal is connected directly further to the conductive layer of the negative, the positive terminal and the negative terminal is said battery element so as to be exposed to the outside The bipolar battery according to any one of claims 2 to 4, which is enclosed in an exterior material. Wherein a material constituting the positive electrode terminal is aluminum, the bipolar battery according to claim 5.

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