JP2008140638A - Bipolar battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lithium battery with a collector saved in weight, high energy density aimed at, and excellent in long-term reliability. <P>SOLUTION: In the bipolar secondary battery provided with a cathode electrically coupled with one face of the collector, an anode electrically coupled with an opposite face of the collector, and an electrolyte layer arranged between them, all of them alternately laminated, an oxidation reduction potential of a cathode active material of the cathode is set lower than an elution potential of the collector, and that, an oxidation reduction potential of an anode active material of the anode is set higher than a lithium alloying potential of the collector. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a bipolar secondary battery having an electrode in which a positive electrode material, a current collector, and a negative electrode material are laminated in this order. The bipolar secondary battery of the present invention is used as a driving power source for motors of electric vehicles, fuel cell vehicles, and hybrid electric vehicles, for example.

  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 lithium ion secondary battery that can achieve a high energy density and a high output density. However, in order to apply to an automobile, it is necessary to use a plurality of secondary batteries connected in series in order to ensure a large output.

  However, when a battery is connected via the connection portion, the output is reduced due to the electrical resistance of the connection portion. Further, the battery having the connection portion has a disadvantage in terms of space. In other words, the output volume and energy density of the battery are reduced due to the occupied volume of the connection portion.

  In order to solve this problem, a bipolar secondary battery in which a positive electrode active material and a negative electrode active material are arranged on both sides of a current collector has been developed. Such a bipolar secondary battery has a configuration in which a bipolar electrode in which a positive electrode is formed on one surface of a metal foil as a current collector and a negative electrode is formed on the opposite surface is laminated with an electrolyte layer interposed therebetween. Therefore, in such a battery, since the current flows only in the thickness direction of the current collector, the resistance in the surface direction does not need to be low. Therefore, it is not necessary to use a thick and thick metal foil as a current collector.

  However, the bipolar secondary battery having such a configuration has problems such as elution of the current collector foil on the positive electrode side and alloying of the current collector foil and lithium (Li) on the negative electrode side.

In order to solve such a problem, Patent Document 1 uses stainless steel, which is an alloy, as the current collector. With such a configuration, the current collector foil of the bipolar battery can be obtained with a single current collector foil. Can be formed.
JP 2001-236946 A

  However, even with such a configuration, it is possible to operate the battery initially, but the battery is actually used for a long time. Therefore, when a long-term battery storage and cycle test is performed with such a configuration, the surface on the positive electrode side corrodes, pinholes are generated, and the durability of the battery is drastically reduced.

  Accordingly, an object of the present invention is to provide a bipolar secondary battery that is light in weight and has a high energy density and is excellent in long-term reliability.

The present invention includes a positive electrode electrically coupled to one surface of the current collector, a negative electrode electrically coupled to the opposite surface of the current collector, and an electrolyte layer disposed therebetween. A bipolar secondary battery in which they are alternately stacked,
A bipolar two-type battery characterized in that the redox potential of the positive electrode active material is lower than the elution potential of the current collector, and the redox potential of the negative electrode active material is higher than the lithium alloying potential of the current collector. This can be achieved with a secondary battery.

  In the bipolar secondary battery of the present invention, the current collector of the bipolar battery can be configured as a single foil, and the weight can be reduced. In addition, since the elution potential of the current collector is higher than the redox potential of the positive electrode active material, and the Li alloying potential of the current collector is lower than the redox potential of the negative electrode active material, a highly reliable bipolar secondary battery can be obtained. It is possible to configure.

The bipolar secondary battery of the present invention is disposed between a positive electrode electrically coupled to one surface of the current collector, a negative electrode electrically coupled to the opposite surface of the current collector, and the positive electrode. A bipolar secondary battery in which the electrolyte layers are alternately stacked,
The redox potential of the positive electrode active material is lower than the elution potential of the current collector, and the redox potential of the negative electrode active material is higher than the lithium alloying potential of the current collector. To do. With such a configuration, a current collector that can withstand the redox potentials of both the positive electrode and the negative electrode active material can be configured with a single current collector, so that the thickness of the current collector can be made sufficiently small and reliable. This is because a high-performance bipolar secondary battery can be configured. As a result, the battery can be reduced in weight, and a battery with a high output density can be formed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the technical scope of the present invention should be determined based on the description of the scope of claims, and is not limited to the following embodiments. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. In addition, the dimensional ratios in the drawings are exaggerated for convenience of explanation, and may be different from the actual ratios.

  FIG. 1 schematically shows an outline of a bipolar lithium ion secondary battery (hereinafter also simply referred to as “bipolar secondary battery”), which is a typical embodiment of the bipolar secondary battery of the present invention. FIG. In the present specification, a bipolar lithium ion secondary battery will be described in detail as an example, but the technical scope of the present invention is not limited to such a form.

  In the bipolar secondary battery 10 of the present embodiment shown in FIG. 1, a substantially rectangular battery element (bipolar battery structure) 21 in which charge / discharge reaction actually proceeds is placed inside a laminate sheet that is a battery exterior material 29. It has a sealed structure.

  As shown in FIG. 1, the battery element 21 of the bipolar secondary battery 10 of the present embodiment is formed with a positive electrode (positive electrode active material layer) 13 electrically coupled to one surface of a current collector 11, A plurality of bipolar electrodes 16 each having a negative electrode (negative electrode active material layer) 15 electrically coupled to the opposite surface of the current collector 11 are formed. Each bipolar electrode 16 is laminated via an electrolyte layer 17 to form a battery element (bipolar battery structure) 21. At this time, each bipolar electrode 16 and the positive electrode 13 of one bipolar electrode 16a and the negative electrode 15 of another bipolar electrode 16b adjacent to the one bipolar electrode 16a face each other through the electrolyte layer 17. Electrolyte layers 17 are alternately stacked. That is, the electrolyte layer 17 is disposed between the positive electrode 13 of one bipolar electrode 16a and the negative electrode 15 of another bipolar electrode 16b adjacent to the one bipolar electrode 16a.

  The adjacent positive electrode 13, electrolyte layer 17, and negative electrode 15 constitute one single battery layer (= battery unit or single cell) 19. Therefore, it can be said that the bipolar secondary battery 10 has a configuration in which the single battery layers 19 are stacked. Further, in order to prevent a liquid junction due to leakage of the electrolytic solution from the electrolyte layer 17, a seal portion 31 is disposed around the single cell layer 19. By providing the seal portion 31, the adjacent current collectors 11 can be insulated and a short circuit due to contact between adjacent electrodes can be prevented. The positive electrode active material layer 13 is formed only on one side of the positive electrode side outermost layer current collector 11 a located in the outermost layer of the battery element (bipolar battery structure) 21. Further, the negative electrode active material layer 15 is formed on only one side of the negative electrode side outermost current collector 11 b located in the outermost layer of the battery element 21.

  Furthermore, in the bipolar secondary battery 10 shown in FIG. 1, the positive electrode side outermost layer current collector 11 a is extended to form a positive electrode tab 25, which is derived from a laminate sheet that is a battery exterior material 29. On the other hand, the negative electrode side outermost layer current collector 11 b is extended to form a negative electrode tab 27, which is similarly derived from a laminate sheet that is a battery exterior material 29.

  Furthermore, in the present invention, as a characteristic configuration, the redox potential of the positive electrode active material of the positive electrode 13 is lower than the elution potential of the current collector 11, and the redox potential of the negative electrode active material of the negative electrode 15 is lower. The current collector 11 is configured to be higher than the lithium alloying potential.

  Here, the oxidation-reduction potential of the electrode can be easily measured by unipolar measurement of the positive electrode 13 or the negative electrode 15. Specifically, the symmetric pole may be lithium metal, a single electrode-lithium battery may be manufactured by sandwiching an electrolyte, and charging / discharging may be performed. Usually, a charging / discharging curve at an infinitely slow rate is obtained by this, and the voltage at which a plateau occurs becomes the oxidation-reduction potential of the electrode. The electrolyte used for the measurement is preferably the same as that which should be applied to the bipolar secondary battery. In other words, the evaluation may be performed using a system actually used. However, it is not limited to this.

  In addition, when determining whether the positive electrode potential or the negative electrode potential does not exceed the elution potential of the current collector and the alloying potential (that is, the level of both potentials), it is easily measured by applying a constant potential to the current collector. it can. Specifically, the symmetry electrode is made of lithium metal, an electrolyte is sandwiched between the current collector and the lithium battery, the redox potential of the positive electrode or the negative electrode is applied, and the current is measured. If the current continues to flow, elution or alloying of the current collector proceeds, and if it does not flow, it is determined that the positive electrode potential or the negative electrode potential does not exceed the elution potential of the current collector and the alloying potential. That is, if no current is flowing, it can be determined that the redox potential of the positive electrode is lower than the elution potential of the current collector, and that the redox potential of the negative electrode is higher than the alloying potential of the current collector. The electrolyte used for the measurement is preferably the same as that which should be applied to the bipolar secondary battery after that. In other words, the evaluation may be performed using a system actually used. However, it is not limited to this. Furthermore, in the present invention, it is not always necessary to specify the elution potential of the current collector and the accurate value of the alloying potential. For example, according to the above measurement, at least the redox potential of the positive electrode active material is lower than the elution potential of the current collector, and at least the redox potential of the negative electrode active material is higher than the Li alloying potential of the current collector. (For details, see the notes in Tables 3 and 5 in the Examples.)

  Hereinafter, the characteristic configuration of the present invention will be described in detail for each preferred embodiment.

(About the first embodiment)
As a preferred embodiment (first embodiment) of the present invention, an olivine positive electrode material is used as a positive electrode active material, carbon or a lithium-transition metal composite oxide is used as a negative electrode active material, iron is used as a current collector. Using a current collector composed of at least one current collector material selected from the group consisting of chromium, nickel, manganese, titanium, molybdenum, vanadium, niobium, copper, silver, gold, and carbon (Refer to Examples 1 to 3 and 5 and Comparative Example 3 described later in comparison).

  In the first embodiment of the present invention, as described above, an olivine-based positive electrode material is selected as the positive electrode active material, and the redox potential of the olivine-based positive electrode material is lower than the elution potential of the current collector. A current collector material is appropriately selected, and a negative electrode material in which the redox potential of the negative electrode active material is higher than the alloying potential of the current collector is appropriately selected.

That is, by using an olivine-based positive electrode material as a positive electrode active material, the redox potential of the positive electrode is lowered, and even a material that is easily eluted as a current collector material can be used, and the number of materials that can be used as a current collector increases. Moreover, the long-term reliability of a battery improves because the average operating voltage of a battery falls. Specifically, when olivine-based materials are used, the average operating voltage is reduced and the output and energy are somewhat reduced, but olivine is used as a result of increased current collector options and improved long-term reliability. (Oxidation-reduction potential of LiFePO ₄ which is an olivine positive electrode material: 3.4 V vs Li ⁺ / Li).

The olivine-based positive electrode material is not particularly limited, and examples thereof include LiFePO ₄ , LiMnPO ₄ , and LiCoPO ₄ , but are not limited thereto. These may be used alone or in combination of two or more.

  In the first embodiment of the present invention, as described above, the negative electrode active material to be combined with the olivine-based positive electrode material may be any negative electrode active material usually used in lithium ion secondary batteries, specifically, carbon or A lithium-transition metal composite oxide can be used. That is, for the current collector that can be combined with the olivine-based positive electrode material, the redox potential of the carbon or lithium-transition metal composite oxide of the negative electrode active material is higher than the alloying potential of these current collectors. This is because it can be done.

  Carbon or lithium-transition metal composite oxide as the negative electrode active material is not particularly limited, and natural graphite, artificial graphite, carbon black, acetylene black, graphite, activated carbon, carbon fiber, coke, and soft carbon. , Carbons such as crystalline carbon materials such as hard carbon (non-graphitizable carbon material) and non-crystalline carbon materials; lithium-transfer metal composite oxides such as lithium-titanium composite oxides, and the like. It is not limited. These may be used alone or in combination of two or more.

  In the first embodiment of the present invention, as described above, the current collector is selected from the group consisting of iron, chromium, nickel, manganese, titanium, molybdenum, vanadium, niobium, copper, silver, gold, and carbon. A current collector made of at least one type of current collector material can be used. By using these current collector materials in combination with the above-described positive electrode and negative electrode active material, the above-described characteristic requirements of the present invention can be achieved, and a highly reliable battery can be configured as a high battery. This is because it becomes possible. In addition, as an example using 2 or more types of each collector material, although stainless steel is common, for example, it is not restrict | limited at all. In the present embodiment, a clad material of nickel and aluminum, a clad material of copper and aluminum, or a plating material of a combination of these current collector materials can be preferably used. That is, in this embodiment, when the negative electrode active material is carbon such as hard carbon or graphite having a low redox potential, the redox potential of the negative electrode active material is lower than the Li alloying potential of the aluminum current collector, The body cannot be configured as a single foil. However, when the current collector is not configured as a single foil, it is not necessary to use aluminum on the negative electrode side, and a clad material composed of Al on the positive electrode side and Ni or Cu on the negative electrode side is used as the current collector. Can do. Also in this case, the negative electrode active material may be anything and is not particularly limited. The current collector may be a current collector obtained by coating the metal surface as the current collector material with another current collector material such as aluminum. In this case as well, other current collector materials such as aluminum coated on the surface by plating or the like need not be used on the negative electrode side, and other current collector materials such as aluminum coated on the positive electrode side of the metal surface may be used. It can be used as a current collector. Moreover, you may use the electrical power collector which bonded together the metal foil which is two or more said electrical power collector materials depending on the case.

  As the current collector, an alloy material mainly containing iron (see Examples 1 to 3), and a current collector using titanium as the material of the current collector (see Example 5). Is effective. The alloy material mainly composed of iron is not particularly limited, but it is preferable to use stainless steel (SUS304, SUS316L, etc.) mainly composed of iron and alloyed with Cr, Ni, or the like. This is because by using these current collectors, a current collector that can withstand both redox potentials of the positive electrode and the negative electrode active material can be obtained. Further, such a current collector is also excellent in that the voltage can be reduced to 0V. In particular, it is preferable to use stainless steel (SUS316L) further containing a Mo component for Cr and Ni (see the comparison between Examples 1 and 2 and Example 3).

(About the second embodiment)
As another preferred embodiment (second embodiment) of the present invention, a lithium-transition metal composite oxide is used as a positive electrode active material, lithium titanate is used as a negative electrode active material, and iron or chromium is used as a current collector. A current collector made of at least one current collector material selected from the group consisting of nickel, manganese, titanium, molybdenum, vanadium, niobium, aluminum, silver, gold, platinum, and aluminum (Refer to Examples 6 to 10 and Comparative Example 2 described later in comparison).

  In the second embodiment of the present invention, as described above, lithium titanate is selected as the negative electrode active material, and the redox potential of the lithium titanate is higher than the lithium alloying potential of the current collector. The current collector material is appropriately selected, and a positive electrode material lower than the elution potential of the current collector is appropriately selected.

That is, by using lithium titanate (Li ₄ Ti ₅ O ₁₂ ) as the negative electrode active material, the redox potential of the negative electrode is increased, and even a material that is easily alloyed can be used as a current collector material, and can be used as a current collector. More materials. Moreover, it is because the long-term reliability of a battery improves because the average operating voltage of a battery falls. Specifically, when lithium titanate is used, the average operating voltage is reduced and the output and energy are somewhat reduced, but the choice of current collectors is increased, and long-term reliability is improved, resulting in the lithium titanate being reduced. It is better to use (redox potential of lithium titanate: 1.5 V vs Li ⁺ / Li).

  In the second embodiment of the present invention, as described above, the positive electrode active material combined with the lithium titanate of the negative electrode active material may be any positive electrode active material that is usually used in lithium ion secondary batteries. Is preferably a lithium-transition metal composite oxide. That is, for the current collector that can be combined with the lithium titanate of the negative electrode active material, the redox potential of the lithium-transition metal composite oxide of the positive electrode active material is lower than the elution potential of these current collectors. This is because it can be configured.

As described above, the positive electrode active material that can be used in the second embodiment is not particularly limited as long as it is a positive electrode active material that is usually used in a lithium ion secondary battery. For example, Li · Co based composite oxides such as LiCoO ₂ , Li · Ni based composite oxides such as layered oxide LiNiO ₂ , Li · Mn based composite oxides such as spinel manganese based LiMn ₂ O ₄ , LiFeO ₂ And Li · Fe-based composite oxides such as olivine-based LiFePO ₄ . In addition, olivine-based transition metals such as LiMnPO ₄ and LiCoPO ₄ and lithium phosphate compounds and sulfate compounds; transition metal oxides such as V ₂ O ₅ , MnO ₂ , TiS ₂ , MoS ₂ , and MoO ₃ , and sulfides. Products; PbO ₂ , AgO, NiOOH and the like. In some cases, two or more positive electrode active materials may be used in combination. Since a battery having excellent capacity and output characteristics can be formed, it is desirable to use a composite oxide of lithium and transition metal (lithium-transition metal composite oxide) as the positive electrode active material. These may be used alone or in combination of two or more.

  Among them, the same olivine-based positive electrode material as that used in the first embodiment is used. However, the use of the olivine-based material on the positive electrode side also increases the choice of current collectors, further improving long-term reliability. It is because it can improve. That is, in this embodiment, the choice of the current collector is increased by using lithium titanate on the negative electrode side, and long-term reliability can be improved. This is because it is possible to obtain further long-term reliability by using an olivine-based positive electrode material capable of exhibiting the action and effect (see comparison between Example 10 and other Examples 1 to 9). .

  In the second embodiment of the present invention, as described above, the current collector is selected from the group consisting of iron, chromium, nickel, manganese, titanium, molybdenum, vanadium, niobium, silver, gold, platinum, and aluminum. A current collector made of at least one current collector material is used. By using these current collector materials in combination with the above-described positive electrode and negative electrode active material, the above-described characteristic requirements of the present invention can be achieved, and a highly reliable battery can be configured as a high battery. This is because it becomes possible. In addition, as an example using two or more kinds of each current collector material, for example, stainless steel which is an alloy material mainly including iron is generally used, but is not limited thereto. In the present embodiment, nickel and aluminum clad materials, or plating materials made of a combination of these metal materials are preferably used. Further, a current collector in which the surface of a metal (excluding aluminum) as the current collector material is coated with aluminum as another current collector material may be used. Moreover, you may use the electrical power collector which bonded together the metal foil which is two or more said electrical power collector materials depending on the case.

  The alloy material mainly composed of iron is not particularly limited, but stainless steel mainly composed of iron and alloyed with Cr and Ni (SUS304), stainless steel having Mo component (SUS316L), and the like. Can be mentioned. By using stainless steel as the current collector, the current collector can withstand both redox potentials of the positive electrode and the negative electrode active material, which is excellent in that the voltage can be reduced to 0V.

  Especially as said collector, platinum, gold | metal | money, and aluminum (refer Examples 6-10) have the effect which prevents elution and alloying of a collector, and improves long-term reliability, and is preferable. In particular, current collectors using pure aluminum (a single metal of aluminum) as a current collector material (see Examples 8 to 10) are prevented from elution and alloying, and long-term reliability. It is more preferable from the viewpoint of corrosion resistance, ease of production, economy, and the like. Furthermore, since aluminum is very light among metal materials, the weight output density of the battery is improved. Moreover, since it is very cheap and easy to process, it is excellent also in that it is easy to manufacture. Note that a single metal (for example, pure aluminum) means a metal (aluminum) having a purity of 98% or more.

(About the third embodiment)
In another preferred embodiment (third embodiment) of the present invention, a lithium-transition metal composite oxide is used as a positive electrode active material, carbon or a lithium-transition metal composite oxide is used as a negative electrode active material, and a current collector. A current collector made of a titanium material is used (refer to comparison between Examples 4 and 5 and Comparative Example 1 described later).

  The third embodiment is a positive electrode active material lithium-transition metal composite oxide and a negative electrode active material carbon or lithium-transition metal composite oxidation that can be used in an ordinary lithium ion secondary battery as in Patent Document 1. Presents a structure that solves the problem of using a stainless steel current collector that can solve the elution of the current collector foil on the positive electrode side and the alloying problem between the current collector foil and Li on the negative electrode side. It will be. That is, as the current collector material for the positive electrode and the negative electrode active material, the redox potential of the positive electrode active material is lower than the elution potential of the current collector, and the redox potential of the negative electrode active material is the lithium alloy of the current collector It is characterized in that it is configured using a current collector material that is configured to be higher than the formation potential. Thereby, when a long-term battery storage and a cycle test are performed, the positive electrode side surface is corroded, pinholes are generated, and the problem that the durability of the battery rapidly decreases can be solved.

  In the third embodiment of the present invention, as described above, a lithium-transition metal composite oxide of a positive electrode active material and a carbon or lithium-transition metal composite of a negative electrode active material that can be used for a normal lithium ion secondary battery. An oxide is selected, the redox potential of the lithium-transition metal composite oxide is lower than the elution potential of the current collector, and the redox potential of the carbon or lithium-transition metal composite oxide is less than that of the current collector. A titanium material is selected as a current collector material configured higher than the lithium alloying potential.

The positive electrode active material that can be used in the third embodiment is not particularly limited as long as it is a positive electrode active material that is usually used in a lithium ion secondary battery as described above. For example, Li · Co based composite oxides such as LiCoO ₂ , Li · Ni based composite oxides such as layered oxide LiNiO ₂ , Li · Mn based composite oxides such as spinel manganese based LiMn ₂ O ₄ , LiFeO ₂ And Li · Fe-based complex oxides such as olivine-based LiFePO ₄ . In addition, phosphoric acid compounds and sulfuric acid compounds of transition metals and lithium such as LiMnPO ₄ and LiCoPO 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 and the like. In some cases, two or more positive electrode active materials may be used in combination. In particular, it is desirable to use a lithium-transition metal composite oxide as the positive electrode active material because a battery having excellent capacity and output characteristics can be configured. These may be used individually by 1 type and may use 2 or more types together.

  As described above, the negative electrode active material that can be used in the third embodiment may be any negative electrode active material that is normally used in lithium ion secondary batteries. Specifically, carbon or lithium-transition metal composites may be used. An oxide can be used.

  Carbon or lithium-transition metal composite oxide as the negative electrode active material is not particularly limited, and natural graphite, artificial graphite, carbon black, acetylene black, graphite, activated carbon, carbon fiber, coke, and soft carbon. , Carbons such as crystalline carbon materials such as hard carbon (non-graphitizable carbon material) and non-crystalline carbon materials; lithium-transfer metal composite oxides such as lithium-titanium composite oxides, and the like. It is not limited. These may be used alone or in combination of two or more.

  In the third embodiment of the present invention, as described above, a current collector made of a titanium material is used as the current collector. By using such a current collector material in combination with the above-described positive electrode and negative electrode active material, the above-described characteristic features of the present invention can be satisfied, and a highly reliable battery can constitute a high battery. Because it becomes possible. That is, the elution of the current collector on the positive electrode side and the alloying of the current collector material and lithium on the negative electrode side are prevented, and the effect of improving long-term reliability is remarkable. Titanium is a current collector material that can only withstand the high redox potential of the positive electrode active material and the low redox potential of the negative electrode active material, and has a combination of a high potential difference between the redox potential of the positive electrode active material and the negative electrode active material. This is because it is possible to maintain a high reliability in the material, to sufficiently reduce the thickness of the current collector, and to form a highly reliable bipolar secondary battery.

  The above is the description regarding the characteristic configuration requirements of the bipolar secondary battery of the present invention, and the other configuration requirements are not particularly limited. Therefore, in the following, regarding the other constituent elements other than the characteristic constituent elements of the bipolar secondary battery of the present invention, the bipolar lithium ion secondary battery will be described as an example, but the present invention is limited to these. It is not a thing.

[Current collector]
The current collector 11 that can be used in the present invention is not particularly limited as long as it has the characteristic constituent features of the bipolar secondary battery of the present invention. Specifically, as described in the first to third embodiments, the current collector may have any characteristic constituent features of the bipolar secondary battery of the present invention. A conductive polymer film mainly composed of a polymer material can also be used. This is because the use of these current collectors can reduce the weight, and the current collector can withstand both redox potentials of the positive electrode and the negative electrode active material. Further, by using such a current collector, the voltage can be reduced to 0V.

  The conductive polymer mentioned here is a filler-dispersed conductive polymer composed of a polymer material and a conductive filler for adding conductivity, and a conductive polymer in which the polymer material itself has conductivity. Includes both.

  Furthermore, as a current collector that can be used in the present invention, a current collector formed by forming a film into a desired shape by a thin film manufacturing technique such as spray coating can be used. For example, a current collector metal paste containing a metal powder such as aluminum, copper, titanium, nickel, stainless steel (SUS304, 316L, etc.) or an alloy thereof as a main component and containing a binder (resin) and a solvent is heated. It is formed by molding. These metal powders may be used singly or as a mixture of two or more, and moreover, by utilizing the characteristics of the manufacturing method, different types of metal powders are laminated in multiple layers. There may be. Preferably, a silicon material (for example, silicon particles having an average particle diameter of about 10 nm to 100 μm, an average fiber diameter of about 10 nm to 100 μm, a fiber length of 0.1 to 0.1%, as a main component for bonding the positive electrode and the negative electrode by electronic conductivity. For example, polyolefins, polyamides, polyimides, etc. are used as the resin (binder) using silicon nanotubes of about 1000 μm, silicon microtubes, silicon nanofibers, silicon microfibers, silicon nanocoils, silicon microcoils, etc. , Polyamide imide, epoxy resin, bakelite, or a mixture of these at a suitable blending ratio may be used. An inexpensive current collector having oxidation resistance can be obtained. As a result, a bipolar secondary battery having long-term reliability can be manufactured at low cost.

  The binder is not particularly limited. For example, a conventionally known resin binder material such as an epoxy resin can be used, and a conductive polymer material may be used.

  Although the thickness of a collector is not specifically limited, Usually, it is about 1-100 micrometers.

  The current collector 11 can be formed using a normal metal foil or a vacuum process. Specifically, PVD (Physical Vapor Deposition) represented by sputtering, vapor deposition, ion plating and thermal spraying, CVD (Chemical Vapor Deposition); Chemical Vapor Deposition or Chemical It can also be formed by any of the vapor deposition method. As the sputtering method, for example, a current collector, an electron cyclotron resonance sputtering method suitable for forming an electrode described later, or an electrolyte layer described later (suitable when a solid electrolyte is used without using a separator). Examples include, but are not limited to, a radio frequency (RF) sputtering method, a magnetron sputtering method, a counter target sputtering method, a mirrortron sputtering method, and an ion beam sputtering method that are suitable for forming a seal portion and the like. Examples of the vapor deposition method include CVD (chemical vapor deposition method) and PVD (physical vapor deposition method). Examples of CVD include, but are not limited to, thermal CVD, plasma CVD, photo CVD, epitaxial CVD, and atomic layer CVD. Examples of PVD include, but are not limited to, sputtering, pulsed laser deposition, vacuum deposition, ion plating, molecular beam epitaxy, electron beam deposition, and thermal spraying.

[Electrodes (positive electrode and negative electrode)]
The structures of the positive electrode (also referred to as positive electrode active material layer) 13 and the negative electrode (also referred to as negative electrode active material layer) 15 are not particularly limited, and known positive electrodes and negative electrodes are applicable. The electrode includes a positive electrode active material if the electrode is a positive electrode and a negative electrode active material if the electrode is a negative electrode.

  The material (material) of the positive electrode active material and the negative electrode active material is not particularly limited as long as it has the characteristic constituent requirements of the bipolar secondary battery of the present invention. What is necessary is just to select suitably according to. Specifically, it is as described in the first to third embodiments.

  In order to reduce the electrode resistance of the bipolar secondary battery, the particle size of the positive electrode active material should be smaller than that generally used for solution (electrolyte) lithium ion secondary batteries that are not bipolar. It is good to use. Specifically, the average particle diameter of the positive electrode active material fine particles is 0.1 to 10 μm, preferably 0.1 to 5 μm.

  The thickness of the positive electrode 13 may be appropriately determined in consideration of the purpose of use of the battery (emphasis on output, importance on energy, etc.) and ion conductivity, and is usually about 1 to 500 μm.

  The positive electrode 13 can be formed using a vacuum process in addition to a method of applying (coating) a normal slurry. Specifically, it can be formed by any of PVD and CVD methods represented by sputtering, vapor deposition, ion plating, thermal spraying and the like as described in the section of the current collector. Examples of the sputtering method include an electron cyclotron resonance sputtering method suitable for forming an electrode and the current collector, a radio frequency (RF) sputtering method suitable for forming an electrolyte layer and a peripheral insulating layer, a magnetron sputtering method, and a counter target. A sputtering method, a mirrortron sputtering method, an ion beam sputtering method, and the like can be mentioned, but are not limited thereto. Examples of the vapor deposition method include CVD and PVD. Examples of CVD include, but are not limited to, thermal CVD, plasma CVD, photo CVD, epitaxial CVD, and atomic layer CVD. Examples of PVD include, but are not limited to, sputtering, pulsed laser deposition, vacuum deposition, ion plating, molecular beam epitaxy, electron beam deposition, and thermal spraying.

  As the positive electrode active material suitable for such a forming method, for example, lithium cobaltate, lithium nickelate, lithium manganate, lithium cobalt nickelate, lithium nickel manganate, lithium cobalt nickel manganate, olivine, and the like can be suitably used. is there. When such a forming method is used, the thickness of the positive electrode can be reduced to 0.001 to 10 μm, preferably 0.01 to 1 μm.

  In order to reduce the electrode resistance of the bipolar secondary battery, the negative electrode active material should have a particle size smaller than that generally used in solution (electrolyte) lithium ion secondary batteries that are not bipolar. It is good to use. Specifically, the average particle diameter of the negative electrode active material fine particles is 0.1 to 10 μm, preferably 0.1 to 5 μm.

  The thickness of the negative electrode 15 may be determined as appropriate in consideration of the intended use of the battery (emphasis on output, importance on energy, etc.) and ion conductivity, and is usually about 1 to 500 μm.

  The negative electrode can be formed by any method of sputtering, vapor deposition, CVD, PVD, ion plating, and thermal spraying in addition to a method of applying (coating) a normal slurry. As the negative electrode active material suitable for such a forming method, carbon, lithium metal, lithium aluminum alloy, lithium tin alloy, lithium silicon alloy and the like can be suitably used in addition to lithium titanate. When such a forming method is used, the thickness of the negative electrode can be reduced to 0.001 to 10 μm, preferably 0.01 to 1 μm.

  Electrodes include a conductive material (hereinafter also referred to as a conductive auxiliary agent) for increasing electron conductivity, a binder, an electrolyte (polymer matrix, ion conductive polymer, electrolyte, etc.), and an electrolyte supporting salt for increasing ion conductivity. (Lithium salt) and the like may be included.

  Examples of the conductive material include acetylene black, carbon black, graphite, and carbon fiber. By including a conductive additive, the conductivity of electrons generated at the electrode can be increased, and the battery performance can be improved.

  Examples of the binder include polyvinylidene fluoride (PVdF), styrene butadiene rubber, and polyimide. However, it is not necessarily limited to these.

  Examples of the electrolyte include polyethylene oxide (PEO), polypropylene oxide (PPO), and ion conductive polymers (solid polymer electrolytes) such as copolymers thereof.

An electrolyte supporting salt (lithium salt) for increasing ion conductivity may be selected according to the type of battery. Bipolar secondary battery, when a bipolar lithium ion secondary battery, as the electrolyte support salt (lithium _{salt), LiPF 6, LiBF 4,} LiClO 4, LiAsF 6, LiTaF 6, LiAlCl 4, Li 2 Inorganic acid anion salts such as B ₁₀ Cl ₁₀ , organic acid anion salts such as LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, Li (C ₂ F ₅ SO ₂ ) ₂ N, or a mixture thereof Etc. can be used. However, it is not necessarily limited to these.

  The compounding amount of the electrode constituent materials such as active material, conductive material, binder, electrolyte (polymer matrix, ion conductive polymer, electrolyte, etc.), electrolyte support salt (lithium salt), etc. It is preferable to determine in consideration of ionic conductivity.

  In the present invention, as shown in the manufacturing method and examples described later, a solid electrolyte (including a gel electrolyte) is further added to void portions formed between particles of electrode constituent materials such as an active material, a conductive material, and a binder. It is desirable to impregnate.

[Electrolyte layer]
The electrolyte layer may be a liquid, gel, or solid phase. In consideration of safety when the battery is damaged and prevention of liquid junction, the electrolyte layer is preferably a solid electrolyte such as a gel polymer electrolyte layer or an all-solid electrolyte layer. By using a solid electrolyte (which will be described later in detail, including a polymer gel electrolyte, a solid polymer electrolyte, and an inorganic solid electrolyte) as the electrolyte layer, it becomes possible to prevent liquid leakage. This is because it is possible to construct a bipolar secondary battery that prevents entanglement and has high reliability. In addition, when a solid electrolyte is used, the gas (bubbles) generated by the initial charge has a structure that does not easily stop between the electrodes, and the benefits of applying the configuration of the present invention can be most enjoyed. This is because the reliability of the bipolar secondary battery can be increased. That is, it can be said that the battery configuration can remarkably exhibit the effects of the present invention. The reliability of the bipolar secondary battery can be improved.

  By using a gel polymer electrolyte layer (polymer gel electrolyte) as the electrolyte layer, the fluidity of the electrolyte is lost, the electrolyte is prevented from flowing out to the current collector, and the ionic conductivity between the layers can be blocked. . Examples of the gel electrolyte host polymer include PEO, PPO, PVdF, polyvinylidene fluoride-hexafluoropropylene copolymer (PVdF-HFP), PAN, PMA, and PMMA. Moreover, as a plasticizer, it is possible to use the electrolyte solution normally used for a lithium ion battery.

  Even when an all-solid electrolyte layer (solid polymer electrolyte, inorganic solid electrolyte) is used as the electrolyte layer, the electrolyte does not flow and the electrolyte does not flow out to the current collector. Can be cut off. When the all solid electrolyte layer is used, the current collector may have a high porosity because there is no fear of permeation of the electrolyte solution from the electrolyte layer. In particular, it is desirable to be an all-solid battery using an all-solid electrolyte layer (further using an all-solid electrolyte as an electrolyte component in the electrodes (positive electrode and negative electrode)). In the present invention, the electrolyte used in the bipolar secondary battery may be a liquid, a gel or a solid. However, particularly when it is a solid, the oxidation reaction hardly occurs and the electrolyte is more durable. This is because the property is improved.

  The gel polymer electrolyte (polymer gel electrolyte) is produced by including an electrolyte solution usually used in a lithium ion battery in an all solid polymer electrolyte such as PEO or PPO. PVdF, PAN, PMMA, and the like, in which the electrolyte solution is held in a polymer skeleton having no lithium ion conductivity, also corresponds to the gel polymer electrolyte (polymer gel electrolyte). The ratio of the polymer constituting the gel polymer electrolyte (polymer gel electrolyte) and the electrolytic solution is not particularly limited. When 100% of the polymer is an all solid polymer electrolyte and 100% of the electrolytic solution is a liquid electrolyte, the intermediate is All are included in the concept of gel polymer electrolyte (polymer gel electrolyte). An inorganic solid electrolyte having ion conductivity such as an inorganic solid such as ceramic corresponds to the all solid electrolyte. Therefore, the polymer gel electrolyte, the solid polymer electrolyte, and the inorganic solid electrolyte are all included in the solid electrolyte.

The electrolyte layer preferably contains a supporting salt in order to ensure ionic conductivity. When the battery is a lithium secondary battery, LiBF ₄ , LiPF ₆ , LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ C ₂ F ₅ ) ₂ , or a mixture thereof is used as the supporting salt. it can. However, it is not necessarily limited to these. As described above, polyalkylene oxide polymers such as PEO and PPO often dissolve lithium salts such as LiBF ₄ , LiPF ₆ , LiN (SO ₂ CF ₃ ) ₂ , and LiN (SO ₂ C ₂ F ₅ ) _2. Yes. Moreover, excellent mechanical strength is exhibited by forming a crosslinked structure.

  Specifically, as the electrolyte layer, conventionally known materials include (a) polymer gel electrolyte (gel polymer electrolyte), (b) all solid polymer electrolyte (polymer solid electrolyte, inorganic solid electrolyte), ( c) Liquid electrolytes (electrolytic solutions) or (d) separators impregnated with these electrolytes (including nonwoven fabric separators) can be used. Preferably, a gel electrolyte material that is excellent in output characteristics, capacity, reactivity, and cycle durability and is a low-cost material can be suitably used.

(A) Gel polymer electrolyte (polymer gel electrolyte)
The gel polymer electrolyte (polymer gel electrolyte) refers to an electrolyte solution held in a polymer matrix. By using a gel polymer electrolyte as the electrolyte, the fluidity of the electrolyte is lost, and it is easy to cut off the ionic conductivity between each layer by suppressing the outflow of the electrolyte to the current collector layer such as a conductive polymer film. Is excellent.

Examples of the polymer matrix (polymer) used as the polymer gel electrolyte or the host polymer of the gel electrolyte include polymers having polyethylene oxide in the main chain or side chain (PEO), polymers having polypropylene oxide in the main chain or side chain ( PPO), polyethylene glycol (PEG), polyacrylonitrile (PAN), polymethacrylic acid ester, polyvinylidene fluoride (PVdF), a copolymer of polyvinylidene fluoride and hexafluoropropylene (PVdF-HFP), poly (methyl methacrylate) ( PMMA) and copolymers thereof are desirable, and among them, PEO, PPO and copolymers thereof, or PVdF-HFP is desirably used. Moreover, as a plasticizer, it is possible to use the electrolyte solution normally used for a lithium ion battery. And such electrolyte, which electrolyte salt dissolved in a solvent, as the _{electrolyte, LiPF 6, LiBF 4, LiClO} 4, LiAsF 6, LiTaF 6, LiAlCl 4, Li 2 B 10 Cl 10 inorganic acid anions such as As a solvent, at least one selected from organic acid anion salts such as ionic salt, LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, Li (C ₂ F ₅ SO ₂ ) ₂ N, etc. Ethylene carbonate (EC), propylene carbonate (PC), γ-butyrolactone (GBL), dimethyl carbonate (DMC), diethyl carbonate (DEC) and mixtures thereof are preferred.

  The ratio of the electrolytic solution in the gel electrolyte in the present invention is not particularly limited, but is preferably about several mass% to 98 mass% from the viewpoint of ionic conductivity. The present invention is particularly effective for a gel electrolyte having a large amount of electrolytic solution in which the proportion of the electrolytic solution is 70% by mass or more.

(B) All solid electrolyte (all solid polymer electrolyte, polymer solid electrolyte, inorganic solid electrolyte)
The use of an all solid electrolyte as the electrolyte is superior in that the fluidity of the electrolyte is lost, the electrolyte does not flow out to the current collector layer, and the ion conductivity between the layers can be blocked.

Examples of the all solid polymer electrolyte include known solid polymer electrolytes such as PEO, PPO, and copolymers thereof, and inorganic solid electrolytes having ion conductivity such as ceramics. The solid polymer electrolyte contains a lithium salt in order to ensure ionic conductivity. As the lithium 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.

(C) Liquid electrolyte (electrolyte)
Examples of the electrolytic solution include those obtained by dissolving an electrolyte salt in a solvent. Here, as the _{electrolyte, LiPF 6, LiBF 4, LiClO} 4, LiAsF 6, LiTaF 6, LiAlCl 4, Li 2 B 10 Cl 10 inorganic acid anion salts such _{as, LiCF 3 SO 3, Li (} CF 3 SO 2 ) At least one selected from organic acid anion salts such as ₂ N, Li (C ₂ F ₅ SO ₂ ) ₂ N, and the solvent is EC, PC, GBL, DMC, DEC and mixtures thereof Is desirable.

  Among electrolytes, a separator impregnated with a gel electrolyte is preferable. This is because a battery having excellent capacity and output characteristics can be configured.

(D) Separator impregnated with the electrolyte (including non-woven separator)
As the electrolyte that can be impregnated in the separator, the same electrolytes as those already described (a) to (c) can be used.

  Examples of the separator include a porous sheet and a nonwoven fabric made of a polymer that absorbs and holds the electrolyte.

  As the porous sheet, for example, a microporous separator can be used. Examples of the polymer include polyolefins such as polyethylene (PE) and polypropylene (PP); laminates having a three-layer structure of PP / PE / PP, polyimide, and aramid. The thickness of the separator cannot be unambiguously defined because it varies depending on the intended use, but a secondary battery for driving a motor such as an electric vehicle (EV), a hybrid electric vehicle (HEV), a fuel cell vehicle (FCV), etc. In the above application, it is desirable that the thickness is 4 to 60 μm in a single layer or multiple layers. The separator preferably has a fine pore size of 1 μm or less (usually a pore size of about several tens of nm) and a porosity of 20 to 80%.

  As the nonwoven fabric, cotton, rayon, acetate, nylon, polyester; polyolefins such as PP and PE; conventionally known materials such as polyimide and aramid are used alone or in combination. The bulk density of the nonwoven fabric is not particularly limited as long as sufficient battery characteristics can be obtained by the impregnated polymer gel electrolyte. The porosity of the nonwoven fabric separator is preferably 50 to 90%. Furthermore, the thickness of the nonwoven fabric separator may be the same as that of the electrolyte layer, preferably 5 to 200 μm, particularly preferably 10 to 100 μm. When the thickness is less than 5 μm, the electrolyte retention deteriorates, and when it exceeds 200 μm, the resistance increases.

Furthermore, in the present invention, the electrolyte layer can be formed by any one of sputtering, vapor deposition, CVD, PVD, ion plating, and thermal spraying. Examples of the electrolyte layer suitable for such a forming method include lithium phosphate oxynitride glass, lithium phosphate, thiolicicon compound, Li ₃ PO ₄ —Li ₂ S—SiS ₂ glass, Li ₂ S—P ₂ S ₅ glass, and the like. It can be suitably used.

[Seal part]
A seal portion (also referred to as a sealant or a peripheral insulating layer) 31 is disposed in the peripheral portion of the unit cell layer 19 in order to prevent the electrolyte layer 17 from leaking. In addition to this, it is possible to prevent the adjacent current collectors in the battery from contacting each other and the occurrence of a short circuit due to slight unevenness at the end of the laminated electrode. For example, polyolefin resin such as PE and PP, epoxy resin, rubber, polyimide and the like can be used as the seal portion 31. From the viewpoint of corrosion resistance, chemical resistance, film forming property, economy, and the like, polyolefin resin is used. preferable. However, it is not limited to these.

  The seal part 31 can also be formed by any of sputtering, vapor deposition, CVD, PVD, ion plating, and thermal spraying. As the seal portion 31 suitable for such a forming method, alumina, silica, magnesia, yttria, or the like can be suitably used.

[Positive electrode and negative electrode tab]
In the bipolar secondary battery 10, the tabs (the positive electrode tab 25 and the negative electrode tab 27) electrically connected to the outermost current collector (11 a, 11 b) are exterior materials for the purpose of taking out current to the outside of the battery. It is taken out of the laminate sheet 29. Specifically, the positive electrode tab 25 electrically connected to the positive electrode outermost layer current collector 11 a and the negative electrode tab 27 electrically connected to the negative electrode outermost layer current collector 11 b are composed of the exterior material 29. Take out to the outside.

  The material constituting the tabs (the positive electrode tab 25 and the negative electrode tab 27) is not particularly limited, and a known highly conductive material conventionally used as a tab for a bipolar secondary battery can be used. As a constituent material of the tab, for example, metal materials such as aluminum, copper, titanium, nickel, stainless steel (SUS), and alloys thereof are preferable, and aluminum, copper, and the like are more preferable from the viewpoint of light weight, corrosion resistance, and high conductivity. Is preferable, and aluminum is particularly preferable. Note that the same material may be used for the positive electrode tab 25 and the negative electrode tab 27, or different materials may be used. Further, the outermost layer current collector (11a, 11b) may be extended to form a tab (25, 27), or a separately prepared tab may be connected to the outermost layer current collector.

  Furthermore, the outermost current collector which is the current collector of the electrode projection surfaces of at least the positive electrode and the negative electrode end electrode, more specifically, the electrode projection surfaces of the positive electrode and the negative electrode end electrode, by the highly conductive tabs 25 and 27 for extracting current. It is desirable to cover all 11a and 11b (see FIG. 1 etc.). This is because the current of the bipolar secondary battery can be received on the surface by adopting such a configuration. As a result, the battery output is improved. More preferably, at least the electrode projection surfaces of the positive electrode and the negative electrode end electrode are covered with the high-conductivity tabs 25 and 27 for taking out the current, and further, the outer case is preferably covered. By reducing the resistance of the outermost current extraction portion, it is possible to reduce the resistance in current extraction in the surface direction. Further, this is because the output of the battery can be increased by reducing the resistance of the current extraction portion.

[Positive electrode and negative electrode terminal plate]
The positive electrode and the negative electrode terminal plate are used as necessary. For example, when the positive electrode tab 25 and the negative electrode tab 27 are directly taken out from the outermost current collectors 11a and 11b, the positive electrode and the negative electrode terminal plate may not be used.

  As a material for the positive electrode and the negative electrode terminal plate, a material used in a conventionally known lithium ion battery can be used. For example, aluminum, copper, titanium, nickel, stainless steel, and alloys thereof can be used. Aluminum is preferably used from the viewpoints of corrosion resistance, ease of production, economy, and the like. Furthermore, from the viewpoint of suppressing internal resistance at the terminal portion, the thickness of the positive electrode and the negative electrode terminal plate is usually preferably about 0.1 to 2 mm.

[Positive electrode and negative electrode lead]
The positive electrode and the negative electrode lead are also used as necessary. For example, when the output electrode terminals (the positive electrode tab 25 and the negative electrode tab 27) are directly taken out from the outermost current collectors 11a and 11b (see FIG. 7), the positive electrode and the negative electrode lead may not be used.

  As a material for the positive electrode and the negative electrode lead, a lead used in a known lithium ion battery can be used. In addition, the parts removed from the battery exterior material should be heat-insulating so that they do not affect products (for example, automobile parts, especially electronic devices) by touching peripheral devices or wiring and causing leakage. It is preferable to coat with a heat shrinkable tube or the like.

[Battery exterior materials]
As the battery exterior material 29, a conventionally known metal can case can be used, and a bag-like case capable of covering the battery element (battery structure) 21 using a laminate film containing aluminum can be used. . For example, a laminate film having a three-layer structure in which PP, aluminum, and nylon are laminated in this order can be used as the laminate film, but the laminate film is not limited thereto.

[Appearance structure of bipolar secondary battery]
FIG. 2 is a perspective view showing the appearance of a laminated flat bipolar secondary battery which is a typical embodiment of the bipolar secondary battery according to the present invention.

  As shown in FIG. 2, the laminated flat bipolar secondary battery 10 has a rectangular flat shape, and a positive electrode tab 25 and a negative electrode tab 27 for taking out electric power from both sides thereof. Has been pulled out. The battery element (battery structure) 21 is encased in a battery exterior material 29 of the bipolar secondary battery 10, and the periphery thereof is heat-sealed. The battery element (battery structure) (not shown) is a positive electrode tab. 25 and the negative electrode tab 27 are pulled out and sealed. Here, the battery element (battery structure) 21 corresponds to the battery element (battery structure) 21 of the bipolar secondary battery shown in FIG. 1 described above, and includes a current collector 11, a positive electrode (positive electrode). A plurality of single battery layers (single cells) 19 up to being composed of an active material layer) 13, an electrolyte layer 17, and a negative electrode (negative electrode active material layer) 15 are laminated.

  The bipolar secondary battery 10 of the present invention is not limited to the laminated flat shape as shown in FIGS. 1 and 2, but in the wound bipolar secondary battery, a cylindrical type is used. There is no particular limitation, for example, it may be a shape, or it may be such that a cylindrical shape is deformed into a rectangular flat shape. In the said cylindrical shape thing, a laminate film may be used for the exterior material, and the conventional cylindrical can (metal can) may be used, for example, It does not restrict | limit. In the case of such a wound type bipolar secondary battery, steps (I) to (III) in the manufacturing method to be described later are performed before winding the battery element (battery structure) in which the gas pool portion is formed. Just do it. That is, after winding the battery element (battery structure) in which the gas pool portion is formed, after the initial charge and then the subsequent charge / discharge, the gas is discharged to the gas pool portion, and then the gas pool What is necessary is just to wind the battery element (battery structure) which formed the part, and to accommodate in the laminated film of an exterior material, and the conventional cylindrical can (metal can), and to seal.

  Further, the removal of the tabs 25 and 27 shown in FIG. 2 is not particularly limited, and the positive electrode tab 25 and the negative electrode tab 27 may be pulled out from the same side, or the positive electrode tab 25 and the negative electrode tab 27 may be drawn out. However, the present invention is not limited to the one shown in FIG. 7, for example. In addition, in a wound bipolar secondary battery, a terminal may be formed using, for example, a cylindrical can (metal can) instead of a tab.

  The bipolar secondary battery according to the present invention is a power source for driving a vehicle or an auxiliary power source that requires high volume energy density and high volume output density as a large capacity power source for an electric vehicle, a hybrid electric vehicle, a fuel cell vehicle, a hybrid fuel cell vehicle and the like. It can utilize suitably for a power supply.

[Battery]
The assembled battery of the present invention is constituted by connecting a plurality of bipolar secondary batteries of the present invention. Specifically, at least two or more are used, and are configured by serialization, parallelization, or both. Capacitance and voltage can be freely adjusted by paralleling in series. In the assembled battery of the present invention, in addition to the bipolar secondary battery of the present invention, other secondary batteries (for example, a normal lithium ion secondary battery that is not bipolar) are used in series and in parallel. Alternatively, an assembled battery can be configured by combining a plurality of them in series or in parallel.

  The number of bipolar secondary batteries and the manner of connection in the assembled battery of the present invention may be determined according to the output and capacity required of the battery. When the assembled battery of this invention is comprised, the stability as a battery increases compared with a bipolar secondary battery single (unit cell). Further, by configuring the assembled battery of the present invention, it is possible to reduce the influence on the entire assembled battery due to deterioration of one single battery layer (single cell) in the assembled battery of the present invention.

  3 is an external view of a typical embodiment of the assembled battery according to the present invention, FIG. 3A is a plan view of the assembled battery, FIG. 3B is a front view of the assembled battery, and FIG. It is a side view of an assembled battery.

  As shown in FIG. 3, an assembled battery 300 according to the present invention forms a small assembled battery 250 in which a plurality of bipolar secondary batteries of the present invention are connected in series or in parallel to be detachable. A plurality of detachable small assembled batteries 250 are connected in series or in parallel, and have a large capacity and a large output suitable for vehicle power supplies and auxiliary power supplies that require high volume energy density and high volume output density. The assembled battery 300 can also be formed. 3A is a plan view of the assembled battery 300, FIG. 3A is a front view, and FIG. 3C is a side view. The small assembled battery 250 that can be attached and detached is an electrical connection means such as a bus bar. The assembled battery 250 is laminated in a plurality of stages using a connection jig 310. How many bipolar secondary batteries are connected to create the assembled battery 250, and how many assembled batteries 250 are stacked to create the assembled battery 300 depends on the vehicle (electric vehicle) to be mounted. It may be determined according to the battery capacity and output.

[vehicle]
The bipolar secondary battery of the present invention or an assembled battery formed by combining a plurality of these can be preferably used as a power source for driving a vehicle. The bipolar secondary battery or the assembled battery of the present invention is, for example, a hybrid vehicle, a fuel cell vehicle, an electric vehicle (all are automobiles, commercial vehicles such as passenger cars, trucks, buses, light vehicles, etc.) This is because it can be used for motorcycles (including motorcycles) and tricycles) to provide a long-life and highly reliable automobile. However, the application is not limited to automobiles. For example, if it is another vehicle, it can be applied to various power sources for moving bodies such as trains, and it can be used for mounting uninterruptible power supplies and the like. It can also be used as a power source.

  The above bipolar secondary battery or an assembled battery formed by combining a plurality of these batteries is a vehicle, for example, a hybrid vehicle, a fuel cell vehicle, an electric vehicle (for automobiles, commercial vehicles such as automobiles, trucks, buses, etc.). In addition to light vehicles, etc., motorcycles (including motorcycles) and tricycles) can be used to provide a long-life and highly reliable vehicle. The present invention can be applied to other vehicles such as trains.

  FIG. 4 is a conceptual diagram of a vehicle equipped with the assembled battery of the present invention.

  As shown in FIG. 4, in order to mount the assembled battery 300 on a vehicle such as the electric vehicle 400, the battery pack 300 is mounted under the seat at the center of the vehicle body of the electric vehicle 400. This is because if it is installed under the seat, the interior space and the trunk room can be widened. The place where the assembled battery 300 is mounted is not limited to the position under the seat, but may be a lower part of the rear trunk room or an engine room in front of the vehicle. The electric vehicle 400 using the assembled battery 300 as described above has high durability and can provide sufficient output even when used for a long period of time. Furthermore, it is possible to provide electric vehicles and hybrid vehicles that are excellent in fuel efficiency and running performance. A vehicle equipped with the assembled battery of the present invention can be widely applied to a hybrid vehicle, a fuel cell vehicle and the like in addition to an electric vehicle as shown in FIG.

[Production method of bipolar secondary battery]
Next, the method for manufacturing the bipolar secondary battery of the present invention is not particularly limited, and can be manufactured by applying a conventionally known method.

(I) Production Process of Bipolar Secondary Battery The production process of the bipolar secondary battery is not particularly limited, and can be produced using a conventionally known production method.

  At this time, when the seal portion 31 is formed, the seal portion 31 and the electrode-electrolyte facing portion 33 are formed on one side, preferably only on one side, of each unit cell layer 19 so that a predetermined gas pool portion 35 is formed. A predetermined interval from the electrode-electrolyte facing portion 33 is formed so that a gas reservoir portion 35 can be formed corresponding to the amount of gas generated by the first charge during this period (preferably, a predetermined margin should be provided). Thus, the sealing portion 31 may be formed.

  Here, the amount of gas generated by the initial charge may be set by measuring the amount of gas generated from the unit cell layer by conducting a preliminary experiment or the like in advance.

  Further, in the present invention, as in the prior art, it is desirable to perform in an inert gas atmosphere from the viewpoint of preventing moisture, air, and the like from remaining in the unit cell layer 19 and the gas pool portion 35 in the seal portion. Is preferably performed under reduced pressure (vacuum). This is because the gas reservoir 35 is kept in a reduced pressure (vacuum) state before the gas discharge step (III) described later is performed, so that when the gas discharge step is performed, the generated gas can be easily stored in the gas. It is because it can discharge | emit to 35 and can accumulate. In addition, when the desired bipolar secondary battery is completed by performing the gas discharge process, the internal pressure of the gas reservoir 35 is not increased, and the seal 31 does not need to have a pressure-resistant structure, and is used for the seal 31. It is excellent in that the material is not limited and the amount used may be small.

  The above is the manufacturing requirement peculiar to the present invention in this step. Manufacturing requirements other than those described above are not particularly limited and will be briefly described below, but it goes without saying that the manufacturing method of the present invention is not limited to these.

(I) Application of positive electrode composition First, an appropriate current collector is prepared. The positive electrode composition is usually obtained as a slurry (positive electrode slurry) and applied to one surface of the current collector. Examples of the application method include bar coating and spray coating, as well as an application method in which printing is performed by screen printing or an inkjet method. Furthermore, it can be formed using a vacuum process as described above. Specifically, PVD (Physical Vapor Deposition; physical vapor deposition or physical vapor deposition), CVD (Chemical Vapor Deposition) or chemical vapor deposition represented by vapor deposition, ion plating, thermal spraying, etc. ). Since the method of forming using these vacuum processes is as already described, the description thereof is omitted here. For the following electrodes, electrolyte layers, seal portions, etc., the method of forming using these vacuum processes can be applied. However, as already explained, the explanation for the following electrodes, electrolyte layers, seal portions is also omitted. To do.

  The positive electrode slurry is a solution containing a positive electrode active material. As other components, a conductive aid, a binder, a polymerization initiator, a polymer gel electrolyte raw material (polymer raw material, electrolytic solution, etc.), a lithium salt, and the like are optionally included. Since a polymer gel electrolyte is used for the polymer electrolyte layer, a conventionally known binder that binds the positive electrode active material fine particles to each other, a conductive auxiliary agent for enhancing electronic conductivity, a slurry such as N-methyl-2-pyrrolidone (NMP) It is sufficient that a viscosity adjusting solvent or the like is included, and the polymer gel electrolyte raw material or lithium salt may not be included.

  Examples of the polymer raw material for the polymer gel electrolyte include PEO, PPO, and copolymers thereof, and preferably have a crosslinkable functional group (such as a carbon-carbon double bond) in the molecule. By cross-linking the polymer raw material using this cross-linkable functional group, the mechanical strength is improved.

  With respect to the positive electrode active material, the conductive additive, the binder, the lithium salt, and the electrolytic solution, the aforementioned compounds can be used.

  The polymerization initiator needs to be selected according to the compound to be polymerized. For example, benzyl dimethyl ketal is used as the photopolymerization initiator, and azobisisobutyronitrile is used as the thermal polymerization initiator.

  A solvent such as NMP is selected according to the type of the positive electrode slurry.

  The addition amount of the positive electrode active material, the lithium salt, the conductive auxiliary agent, etc. may be adjusted according to the purpose of the bipolar secondary battery, etc., and the amount usually used may be added. The addition amount of the polymerization initiator is determined according to the number of crosslinkable functional groups contained in the polymer raw material. Usually, it is about 0.01-1 mass% with respect to a polymeric raw material.

(Ii) Formation of positive electrode The current collector coated with the positive electrode slurry is dried to remove the solvent contained therein to form the positive electrode. At the same time, depending on the positive electrode slurry, the cross-linking reaction may be advanced to increase the mechanical strength of the polymer solid electrolyte. For drying, a vacuum dryer or the like can be used. The drying conditions are determined according to the applied positive electrode slurry and cannot be uniquely defined, but are usually 40 to 150 ° C. and 5 minutes to 20 hours.

  The produced positive electrode is preferably subjected to a pressing operation in order to improve surface smoothness and thickness uniformity. The press operation may be either a cold press roll method or a hot press roll method. In the case of a hot-rolling method, it is desirable to carry out at a temperature below the temperature at which the electrolyte supporting salt and the polymerizable polymer are decomposed. The pressing pressure is desirably a linear pressure of 200 to 1000 kg / cm.

(Iii) Application of negative electrode composition A negative electrode composition (negative electrode slurry) containing a negative electrode active material is applied to the surface of the current collector opposite to the surface on which the positive electrode is formed.

  The negative electrode slurry is a solution containing a negative electrode active material. As other components, a conductive assistant, a binder, a polymerization initiator, a polymer gel electrolyte raw material (polymer raw material, electrolytic solution, etc.), a lithium salt, and the like are optionally included. Since the raw materials used and the addition amount are the same as those described in the section “(i) Application of positive electrode composition”, description thereof is omitted here.

(Iv) Formation of negative electrode The current collector coated with the negative electrode slurry is dried to remove the solvent contained therein, thereby forming the negative electrode. At the same time, depending on the slurry for the negative electrode, the crosslinking reaction may be advanced to increase the mechanical strength of the polymer gel electrolyte. This work completes the bipolar electrode. For drying, a vacuum dryer or the like can be used. The drying conditions are determined according to the applied slurry for negative electrode and cannot be uniquely defined, but are usually 40 to 150 ° C. and 5 minutes to 20 hours.

  In addition, the press operation described in the section “(ii) Formation of positive electrode” is performed by, for example, forming a positive electrode active material layer on one side of a current collector, and then forming a whole for a plurality of positive electrode active material layers used in a battery. You may go together. The same applies to the negative electrode active material layer. Furthermore, after the positive electrode active material layer is formed on one surface of the current collector and the negative electrode active material layer is formed on the other surface, the positive electrode active material layer and the negative electrode active material layer may be pressed together. This is because the man-hours required for the pressing operation can be greatly reduced. On the other hand, from the viewpoint of securing a predetermined film thickness for each layer constituting the positive electrode active material layer and the negative electrode active material layer, it is desirable to carry out for each layer constituting the positive electrode active material layer and the negative electrode active material layer. Thus, what is necessary is just to select suitably the object and time of press operation as needed. In addition, the pressing condition is a case where a plurality of positive electrode active material layers and / or negative electrode active material layers used in the battery are collectively performed even for each layer of the positive electrode active material layer or the negative electrode active material layer. Can also be prepared within the range described in the section “(ii) Formation of positive electrode”.

(V) Production of bipolar electrode and electrolyte layer (production of electrolyte)
A gel raw material solution (pre-gel solution) or a precursor of a solid electrolyte is formed on the positive and negative electrode surfaces on both sides of the bipolar electrode prepared as described above, and at a predetermined position of the separator (center portion: electrode area or larger area). A body solution is impregnated and polymerized to produce a bipolar electrode and an electrolyte layer. Thereby, the ion conductivity of the electrode can be increased and a desired electrolyte layer can be formed. In addition, by impregnating the pore portion of the electrode with gel electrolyte or solid electrolyte, the gas (bubbles) generated by the first charge is more difficult to escape through the pore portion of the electrode or electrolyte layer. As described above, in the bipolar secondary battery having a structure in which the gas reservoir is intentionally provided and the generated gas is discharged, the effect of increasing the ion conductivity of the electrode is effectively expressed, and the generated gas ( It is excellent in that the battery performance can be prevented from deteriorating without hindering ion conduction due to air bubbles).

  The gel raw material solution (pregel solution) impregnated in the bipolar electrode means a solution prepared by dissolving a raw material polymer (host polymer) of a polymer gel electrolyte, a lithium salt, a polymerization initiator and the like in a solvent. Since the host polymer, the lithium salt, and the like are the same as those described in the positive electrode of the bipolar secondary battery, the description thereof is omitted here.

  The solid electrolyte precursor solution impregnated in the bipolar electrode means a solution prepared by mixing a raw material polymer (host polymer) of a polymer solid electrolyte, a lithium salt, a polymerization initiator, and the like. Since the host polymer, the lithium salt, and the like are the same as those described in the positive electrode of the bipolar secondary battery, the description thereof is omitted here.

  The polymerization initiator needs to be appropriately selected according to the polymerization method (thermal polymerization method, ultraviolet polymerization method, radiation polymerization method, electron beam polymerization method, etc.) and the compound to be polymerized. For example, benzyl dimethyl ketal as an ultraviolet polymerization initiator and azobisisobutyronitrile and the like as a thermal polymerization initiator can be mentioned, but it should not be limited to these. Examples of the solvent include slurry viscosity adjusting solvents such as N-methyl-2-pyrrolidone (NMP) and n-pyrrolidone. The addition amount of the polymerization initiator is determined according to the number of crosslinkable functional groups contained in the host polymer. Usually, it is about 0.01-1 mass% with respect to the said host polymer.

  The impregnation with the gel raw material solution or the solid electrolyte precursor solution is applied to the entire surface of the positive electrode and negative electrode on both sides of the bipolar electrode and the central portion on the separator, and dried by vacuum drying (the solvent is removed in the case of the gel raw material solution). Thus, a bipolar electrode containing a gel electrolyte or an all solid electrolyte in the gap between the positive electrode and the negative electrode, and an electrolyte layer containing a gel electrolyte or an all solid electrolyte in the porous portion of the separator can be obtained. . Since the gel raw material solution or the precursor solution of the solid electrolyte has not yet become a gel or solid, it penetrates into the electrode and the separator. Further, for impregnation, if an applicator or a coater is used, a very small amount can be supplied.

  Thereafter, the electrode polymer impregnated with the gel raw material solution or the solid electrolyte precursor solution and the host polymer contained in the separator are polymerized (crosslinked) by heat, ultraviolet rays, radiation, electron beams or the like. Since the polymerization can be carried out simply and reliably, it is desirable to carry out the polymerization. For drying or thermal polymerization, a conventionally known apparatus such as a vacuum dryer can be used. The conditions for drying or thermal polymerization may be appropriately determined according to the gel raw material solution or the solid electrolyte precursor solution. The size (area) of the electrolyte application part of the separator obtained may be slightly smaller or the same as the size (area) of the electrode forming part of the current collector of the single battery layer (single cell). However, it may be slightly larger, and is not particularly limited.

  In the present invention, the electrolyte layer is preferably polymerized (crosslinked) by impregnating a separator with a gel raw material solution or a solid electrolyte precursor solution (polymer electrolyte raw material solution). By using the separator, the filling amount of the electrolytic solution can be increased and the thermal conductivity can be secured, so that it is preferably used. However, the electrolyte layer of the present invention is not limited to such a configuration, and a conventionally known electrolyte layer that does not include a separator may be used.

  The bipolar electrode produced as described above is sufficiently heated and dried under high vacuum, and then a plurality of bipolar electrodes and electrolyte layers are cut into appropriate sizes. The electrolyte layer is desirably slightly larger than the current collector size of the bipolar electrode.

(Vi) Formation of seal portion precursor A seal portion precursor is formed on the outer peripheral portion (all four sides) of the electrode 13 by using a dispenser or the like on the electrode uncoated portion of the positive electrode periphery of the bipolar electrode obtained in (v) above. A body (for example, a one-part uncured epoxy resin) is applied.

  Next, the electrolyte layer obtained in the above (v) is installed on the positive electrode side so as to cover the current collector.

  After that, in the electrolyte layer, a dispenser or the like is applied to the electrode uncoated portion (= the gel electrolyte uncoated portion; the same portion as the portion where the seal portion precursor is coated) from above the separator in the vicinity of the outer periphery of the gel electrolyte. The seal part precursor (for example, one-component uncured epoxy resin) is applied to the separator on the outer periphery of the electrolyte layer and impregnated. You may apply | coat in several times as needed so that a seal | sticker part precursor may be located in a separator inside (impregnation) and the upper part (position corresponding to the electrode non-application part of a negative electrode peripheral part). As for the application position of the seal portion precursor, it may be applied so that the volume B of the gas reservoir (gas reservoir portion) and the volume A of three sides are obtained.

  Furthermore, in the present invention, a gas adsorbing layer containing a gas adsorbing material such as activated carbon may be disposed in the gas reservoir on the negative electrode side as required, as shown in FIG. The gas adsorbing slurry used for forming the gas adsorbing layer is prepared by adding a gas adsorbing material, a binder similar to that used for the electrode, and an appropriate viscosity adjusting solvent such as NMP, and mixing them to prepare a gas adsorbing slurry. After the negative electrode is formed on the current collector, the gas adsorbing layer may be formed by applying and drying the outer peripheral portion of the current collector on the negative electrode side. What is necessary is just to form this gas adsorption layer in the shape of a frame in the outer peripheral part (inside a gas pool part) between a negative electrode and a seal part. Further, a negative electrode in which the hard carbon electrode portion on the negative electrode side is extended to the gas reservoir portion as shown in FIG. 5 may be prepared, and a gas adsorption layer formed of a negative electrode material may be formed on the gas reservoir portion.

  In addition, when performing the said process (i)-(vi), it is preferable to carry out in inert atmosphere, such as argon and nitrogen, from a viewpoint which prevents a water | moisture content etc. mixing in the inside of a battery.

(Vii) Fabrication of battery element (battery structure) The positive electrode (active material layer) and the negative electrode (active material layer) serve as the electrolyte layer while the bipolar electrode and the electrolyte layer obtained above are sealed in vacuum (reduced pressure). The layers are alternately laminated so as to face each other, and the surface pressure is 0.1 to 2.0 kg / cm ² , preferably 0.5 to 1.0 kg / cm ² , more preferably 25 to 150 by a hot press. The uncured seal portion precursor is cured by hot pressing at 0.1 ° C., preferably 45 to 100 ° C., more preferably 60 to 80 ° C. for 0.1 to 2 hours, preferably 0.5 to 1 hour. This step is a value determined by the adhesive used, and is determined by, for example, the curing temperature of the epoxy resin or the melting point of the olefinic hot melt. In this step (vii), a battery element (battery structure) in which a desired number of single battery layers (single cells) are stacked can be created by pressing the seal portion to a predetermined thickness and further curing. The number of stacked layers is determined in consideration of battery characteristics required for a bipolar secondary battery. A bipolar electrode having an electrolyte layer formed on one surface or both surfaces may be directly bonded. On the outermost electrolyte layer, electrodes for taking out current are respectively arranged. In the outermost layer on the positive electrode side, an electrode for current extraction in which only the positive electrode is formed on the current collector is disposed. In the outermost layer on the negative electrode side, a current extracting electrode in which only the negative electrode is formed on the current collector is disposed. The step of obtaining a bipolar secondary battery by laminating a bipolar electrode and an electrolyte layer may be performed under an inert atmosphere (for example, under an argon atmosphere or a nitrogen atmosphere), as in the prior art. Then, in this manufacturing process, after sequentially laminating the bipolar electrode and the electrolyte layer, a vacuum (reduced pressure) is applied, and the atmosphere gas (inert gas or air) inside the seal portion including the gas reservoir portion is exhausted, It is desirable that the uncured seal portion precursor is cured and vacuum-sealed by hot pressing with a press. Thereby, the battery element (battery structure) in which the inside of the gas reservoir portion vacuum-sealed by the seal portion is in a vacuum (reduced pressure) state can be formed. As a vacuum (reduced pressure) condition here, it is desirable that the atmospheric pressure is 2 kPa or less, preferably 1 kPa or less, more preferably 0.5 kPa or less with respect to 101.3 kPa. Further, in such a vacuum environment, it is desirable that the entire process from the lamination operation of the bipolar electrode and the electrolyte layer to the hot press machine is evacuated. Such a vacuum environment can be performed using, for example, a vacuum laminating apparatus in which a laminating mechanism is added inside a vacuum chamber using a high-performance vacuum pump.

(Viii) Attaching electrode tabs A positive electrode tab and a negative electrode tab are disposed (electrically connected) to the current collector of the single battery layer on the outermost side of both batteries of the obtained battery element (battery structure). The tab attached to the current collector of the battery cell outermost layer may be bonded with a carbon-based conductive adhesive or the like.

  If necessary, a positive electrode lead and a negative electrode lead may be further joined (electrically connected) to the positive electrode tab and the negative electrode tab, respectively. The method for joining the positive electrode lead and the negative electrode lead is not particularly limited, but ultrasonic welding having a low bonding temperature can be suitably used. A known joining method can be used as appropriate, and it may be bonded with a carbon-based conductive adhesive or the like in the same manner as the tab.

(Ix) Production of Bipolar Secondary Battery Next, the battery element (battery structure) to which this electrode tab is attached is applied to a battery exterior material or battery such as an aluminum laminate in order to prevent external impact and environmental degradation. The case is vacuum-sealed and the outer periphery is sealed by thermal fusion to produce a bipolar secondary battery (before initial charging and degassing). The material of the battery exterior material (metal-polymer laminate material) is preferably a metal (aluminum, stainless steel, nickel, copper, etc.) whose inner surface is coated with an insulator such as a polypropylene film.

  The above is the whole process of the manufacturing method of the bipolar secondary battery of the present invention.

  In the method for manufacturing a bipolar secondary battery of the present invention, it is desirable to use an assembling method as used in the examples described later. Hereinafter, these assembling methods will be described with reference to the drawings.

  FIG. 5 is a process diagram for explaining the manufacturing method of the bipolar battery (electrolyte-based bipolar battery) according to the first embodiment.

  The bipolar battery manufacturing method according to Embodiment 1 includes an electrode forming step, a seal portion precursor arranging step, an electrode setting step, an electrolyte layer forming step, a vacuum introducing step, an electrode stacking step, a pressing step, and a vacuum releasing step. Have

  Next, each step will be described in order with reference to FIGS.

  6 is a front view for explaining the positive electrode according to the electrode forming step shown in FIG. 5, FIG. 7 is a rear view for explaining the negative electrode according to the electrode forming step shown in FIG. 5, and FIG. It is sectional drawing regarding line VIII-VIII of FIG.

  In the electrode forming step, first, the positive electrode slurry is adjusted. The positive electrode slurry has, for example, a positive electrode active material, a conductive additive and a binder adjusted to a predetermined ratio, and is adjusted to a predetermined viscosity by adding a viscosity adjusting solvent, but is not limited to these. is not.

  The positive electrode active material, conductive additive, binder and viscosity adjusting solvent can be appropriately selected from those described above.

  The positive electrode slurry is applied to one surface of the current collector 111 having a predetermined thickness and material, for example. The coating film of the positive electrode slurry is dried using, for example, a vacuum oven to form the positive electrode 113 composed of a positive electrode active material layer having a predetermined thickness. At this time, the viscosity adjusting solvent is removed by volatilization.

  Next, the negative electrode slurry is adjusted. The negative electrode slurry has a negative electrode active material adjusted to a predetermined ratio, a binder, and, if necessary, a conductive additive, and is adjusted to a predetermined viscosity by adding a viscosity adjusting solvent. The negative electrode active material conductive additive, the binder, and the viscosity adjusting solvent can be appropriately selected from those described above.

  The negative electrode slurry is applied to the other surface of the current collector 111. The coating film of the negative electrode slurry is dried using, for example, a vacuum oven to form the negative electrode 112 made of a negative electrode active material layer having a predetermined thickness. At this time, the viscosity adjusting solvent is removed by volatilization.

  As a result, a bipolar electrode 110 (a bipolar battery without an electrolyte layer) 110 in which the positive electrode 113 and the negative electrode 112 are formed on one surface and the other surface of the current collector 111 is obtained.

  The bipolar battery 110 is cut to a predetermined size. The outer peripheral parts of the positive electrode 113 and the negative electrode 112 are peeled off with an appropriate width, specifically 5 to 20 mm, preferably 10 to 15 mm, in order to expose the current collector.

  The thicknesses of the positive electrode 113 and the negative electrode 112 are not particularly limited, and are set in consideration of the intended use of the battery (for example, emphasis on output and energy) and ion conductivity.

  9 is a front view for explaining the first seal portion precursor in the seal portion precursor arrangement step shown in FIG. 5, FIG. 10 is a cross-sectional view taken along line XX in FIG. 9, and FIG. FIG. 12 is a cross-sectional view taken along line XII-XII in FIG. 9, illustrating a second seal portion precursor in the seal portion precursor arranging step shown in FIG.

  In the seal part precursor arranging step, first, a first seal part precursor (one-component uncured epoxy resin) 114 is arranged on the outer peripheral part of the positive electrode side where the current collector 111 is exposed. At this time, the non-arranged portion is provided with an appropriate width from the end face of the outer peripheral portion, specifically, a width of 10 to 15 mm. For example, application using a dispenser is applied to the arrangement of the first seal portion precursor 114.

  Next, the separator 120 is arrange | positioned so that all the positive electrode side surfaces of the electrical power collector 111 may be covered. The separator 120 is not particularly limited, and those described above can be used, and the thickness and size are also the same. Since it is desirable that the separator 120 covers all of the positive electrode side surface of the current collector 111, the size of the separator 120 is desirably 5 to 10 mm larger in length and width than the size of the positive electrode side surface of the current collector 111.

  Thereafter, a second seal portion precursor (for example, a one-component uncured epoxy resin) 116 is disposed on the separator 120. At this time, the second seal portion precursor 116 is positioned so as to be opposed (overlapped) with the arrangement site of the first seal portion precursor 114. For example, application using a dispenser is applied to the arrangement of the second seal portion precursor 116.

  The constituent material of the first seal portion precursor 114 and the second seal portion precursor 116 is not limited to the one-component uncured epoxy resin, and a material that exhibits a good sealing effect in the use environment may be used depending on the application. It can be selected appropriately. For example, other thermosetting resins (polypropylene, polyethylene, etc.) and thermoplastic resins can be applied.

  As a constituent material of the separator 120, other polyolefins such as polyethylene and polypropylene, resin materials such as polyamide and polyimide can be applied.

  FIG. 13 is a schematic view for explaining a clip mechanism of the holding mechanism according to the electrode setting step shown in FIG. 5, and FIG. 14 is a cross-sectional view for explaining the electrode setting step.

  In the electrode setting step, a predetermined number of bipolar electrodes 110 (110A to 110F) (six examples are shown in the figure) are set in the electrode stocker (laminating means) 150 with the negative electrode face up. . In the bipolar battery 110F held at the lowest position, the first seal portion precursor 114, the second seal portion precursor 116, and the separator 120 are not arranged.

  The electrode stocker (stacking means) 150 includes a holding mechanism, a support structure 154, a cradle 156, a position sensor 158, and a control unit (not shown).

  The holding mechanism has six clip mechanisms 153 that can grip two opposing portions of the outer peripheral portion of the bipolar battery 110, and can set six bipolar batteries 110. The part of the bipolar battery 110 gripped by the clip mechanism 153 is located in a region having a width of about 10 mm from the outer peripheral end surface, and the first seal portion precursor 114 and the second seal portion precursor 116 are not disposed. It is an unarranged part.

  The clip mechanism 153 is based on elastic force and includes lower and upper arms 191 and 193, a guide block 195, a movable block 197 and a drive rod 198.

  The lower arm 191 has a distal end portion on which the bipolar battery 110 is placed and a base portion that extends from the distal end portion via a lower stepped portion 192. The upper arm 193 has a tip portion that presses the bipolar battery 110, an intermediate portion that extends from the tip portion via the first upward inclined portion, and a base portion that extends from the intermediate portion via the second upward inclined portion 194. . The lower and upper arms 191 and 192 are elastically biased so as to be close to each other, for example, by an elastic member (not shown) made of a spring.

  The guide block 195 is fixed to the base of the lower arm 191 and has a through hole 196. The movable block 197 is disposed between the guide block 195 and the lower step 192 of the lower arm 191, and is elastically biased toward the guide block 195 by, for example, an elastic member (not shown) made of a spring. Yes.

  The drive rod 198 is disposed so as to freely reciprocate, and the diameter of the drive rod 198 is set so as to pass through the through hole 196 of the guide block 195. Accordingly, the tip of the drive rod 198 protruding from the through hole 196 presses the movable block 197 and moves it toward the lower step 192 of the lower arm 191.

  Since the movable block 197 is in contact with the second upper inclined portion 194 of the upper arm 193, the movement of the movable block 197 causes the upper arm 193 to rise.

  That is, when the drive rod 198 is protruded, the tip portions of the lower and upper arms 191 and 192 are separated from each other, so that the bipolar battery 110 can be disposed or released (released). . On the other hand, when the drive rod 198 is retracted, the tip portions of the lower and upper arms 191 and 192 are close to each other, so that the bipolar battery 110 can be gripped. The clip mechanism 153 is not particularly limited to the above configuration as long as the bipolar battery 110 can be gripped.

  The support structure 154 has a frame shape and a holding mechanism attached to avoid interference when the bipolar battery 110 is set. The holding mechanism is attached in a direction (Z-axis direction) perpendicular to the surface direction (XY-axis direction) of the bipolar battery 110 so that the bipolar batteries 110 are aligned and do not contact each other.

  The support structure 154 is provided with Z-axis moving means (not shown) for moving in a vertical direction toward the cradle 156. Since the Z-axis moving means moves the support structure 154 relative to the cradle 156, the installation space can be used effectively. In particular, since the electrode stocker 150 is disposed inside a vacuum processing apparatus 160 (described later), the equipment cost can be reduced by downsizing the vacuum processing apparatus 160.

  When the Z-axis moving means is disposed on the support structure 154, the structure of the cradle 156 and its surroundings can be simplified. However, the Z-axis moving means is disposed on the cradle 156 and supports the cradle 156. It is also possible to move relative to the structure 154. In this case, the support structure 154 is fixed, and the cradle 156 moves inside the support structure 154, so that the support structure 154 can be prevented from shaking.

  The cradle 156 is used to support the stacked bipolar battery 110. The cradle 156 is provided with XY axis moving means (not shown) for moving in the plane direction of the bipolar battery 110. In addition, by making one axial direction of the XY axis moving means coincide with the moving direction of the cradle 156 to the next process, the XY axis moving means can also be used as a moving mechanism for the cradle 156 to the next process. Is also possible.

  The position sensor 158 is disposed at a position corresponding to the four sides of the bipolar battery 110 on the upper surface of the support structure 154 and constitutes a two-dimensional position detection unit. Therefore, the position sensor 158 can detect a positional shift during the relative movement of the bipolar battery 110, that is, during the movement of the bipolar battery 110 toward the cradle 156. As the two-dimensional position detection means, for example, a CCD (solid-state imaging device) image sensor can be used. In this case, the two-dimensional position detection means can be configured by disposing at one of the four corners on the upper surface of the support structure 154.

  The control unit is used to stack the bipolar battery 110 held by the clip mechanism 153. For example, the control unit controls the holding and release of the bipolar battery 110 by the clip mechanism 153 and the detection result of the position sensor 158. Based on the control of the XY axis moving means. Therefore, the position sensor 158 and the XY axis moving unit constitute a correcting unit for correcting a positional deviation when the bipolar battery 110 is relatively moved.

  In the electrolyte layer forming step, 1 ml of the electrolyte is applied to the negative electrodes 112 of the five bipolar batteries 110B to 110F, excluding the bipolar battery 110A held at the top, using, for example, a micropipette. It is infiltrated by putting it on the surface.

The electrolytic solution contains an organic solvent composed of PC (propylene carbonate) and EC (ethylene carbonate), a lithium salt (LiPF ₆ ) as a supporting salt, and a small amount of a surfactant. The lithium salt concentration is 1M.

The organic solvent used for the electrolytic solution is not particularly limited to PC and EC. For example, other cyclic carbonates, chain carbonates such as dimethyl carbonate, and ethers such as tetrahydrofuran can be applied. The lithium salt is not particularly limited to LiPF ₆ , and other inorganic acid anion salts and organic acid anion salts such as LiCF ₃ SO ₃ can be applied.

  15 is a schematic diagram for explaining the vacuum processing apparatus according to the vacuum introduction process to the vacuum release process shown in FIG. 5, and FIG. 16 is a schematic diagram for explaining the electrode stacking process shown in FIG. 17 is a cross-sectional view for explaining the pressing step shown in FIG.

  The vacuum processing apparatus 160 includes a vacuum unit 162, a press unit 172, and a control unit 178.

  The vacuum unit 162 includes a vacuum chamber 163, a vacuum pump 164, and a piping system 165. The vacuum chamber 163 has a detachable (openable) lid, and a fixed base on which the electrode stocker 150 and the press means 172 are arranged. The vacuum pump 164 is, for example, a centrifugal type, and is used to bring the inside of the vacuum chamber 163 into a vacuum state. The piping system 165 is used to connect the vacuum pump 164 and the vacuum chamber 163, and a leak valve (not shown) is arranged.

  The press unit 172 includes a lower press plate 174, an upper press plate 176, a lower heating unit 175, and an upper heating unit 177 that are disposed so as to be close to and away from the lower press plate 174.

  The lower press plate 174 is provided with a receiving base 156 of the electrode stocker 150. The upper press plate 176 is used to press the stacked body of the bipolar batteries 110 in cooperation with the lower press plate 174.

  The lower heating means 175 and the upper heating means 177 have, for example, resistance heating elements and are disposed inside the lower press plate 174 and the upper press plate 176, and raise the temperature of the lower press plate 174 and the upper press plate 176. Used to make.

  The control unit 178 controls the temperature of the upper press plate 176 and the temperature of the lower heating unit 175 and the upper heating unit 177 to perform appropriate heat pressing on the stacked body of the bipolar battery 110 under vacuum. Used to do.

  Note that one of the lower heating unit 175 and the upper heating unit 177 can be omitted, or the lower heating unit 175 and the upper heating unit 177 can be arranged outside the lower press plate 174 and the upper press plate 176. .

  Next, a vacuum introduction process to a vacuum release process to which the vacuum processing apparatus 160 is applied will be sequentially described.

  In the vacuum introduction process, the lid of the vacuum chamber 163 is removed, and the electrode stocker 150 holding the bipolar battery 110 is disposed at the base of the vacuum chamber 163. When the lid of the vacuum chamber 163 is attached and the vacuum chamber 163 is sealed, the vacuum pump 164 is operated and the inside of the vacuum chamber 163 is evacuated.

  In the electrode stacking step, the support structure 154 of the electrode stocker 150 is moved toward the cradle 156 under vacuum by the Z-axis moving means. That is, the holding mechanism (clip mechanism 153) and the cradle 156 are relatively moved by the Z-axis moving unit in the direction perpendicular to the surface direction of the bipolar battery 110. Since the relative movement suppresses the shake of the bipolar battery 110, the bipolar battery 110 is stacked with high accuracy.

  Then, when the bipolar battery 110 held by the clip mechanism 153 of the support structure 154 comes into contact with the cradle 156, the drive rod 198 of the clip mechanism 153 is controlled to cancel the holding of the bipolar battery 110. .

  On the other hand, when the position sensor 158 detects a positional shift during the relative movement of the bipolar battery 110, the XY axis moving means is controlled, and the position in the surface direction of the cradle 156 is adjusted. This further improves the stacking accuracy. Further, since the cradle 156 is irrelevant to the holding mechanism, the movement of the cradle 156 does not affect the position of the bipolar battery 110 and the positional deviation can be easily adjusted.

  Then, by continuing the movement of the support structure 154 with respect to the cradle 156, the bipolar batteries 110F to 110A are sequentially stacked.

  As described above, blurring of the bipolar battery 110 is suppressed, and the bipolar batteries can be stacked with high accuracy. Therefore, the occurrence of displacement between the bipolar electrode and the electrolyte layer constituting the bipolar battery 110 is suppressed and the occurrence of an internal short circuit can be avoided, so that the occurrence of defective products can be reduced.

  In addition, since the layers are stacked under vacuum, mixing of bubbles with respect to the stack interface between the electrode and the electrolyte layer is suppressed. Therefore, the movement of ions during use is not harmed and the battery resistance does not increase, so that a high output density can be achieved. That is, since a bipolar battery in which the mixing of bubbles is suppressed is obtained, the movement of ions during use is not harmed, and the battery resistance does not increase, so that a high output density can be achieved.

  Note that the XY-axis moving means is not limited to being disposed on the cradle 156, and by placing it on the holding mechanism, the structure of the cradle 156 and the vicinity thereof can be simplified. Further, the Z-axis moving means can be arranged in the clip mechanism 153.

In the pressing process, the cradle 156 of the electrode stocker 150 is disposed on the lower press plate 174. At this time, the pedestal 156 holds the stacked body 100 of the bipolar batteries 110 formed by the electrode stacking process. The upper press plate 176 descends toward the lower press plate 174, presses the laminated body 100, and applies a surface pressure of 1 kg / cm ² .

  On the other hand, the lower heating means 175 and the upper heating means 177 are operated to heat the laminate of the bipolar battery 110 via the lower press plate 174 and the upper press plate 176. The laminated body of the bipolar battery 110 is heated to 80 ° C., which is the curing temperature of the one-component uncured epoxy resin that constitutes the first seal portion precursor 114 and the second seal portion precursor 116.

The first seal portion precursor 114 and the second seal portion precursor 116 are held for 1 hour under the pressing conditions (surface pressure 1 kg / cm ² and 80 ° C.) while maintaining the vacuum state in the electrode stacking step. Is cured to form the first seal 115 and the second seal 117 having a predetermined thickness, and the laminate 100 is obtained.

  As described above, since the presses are laminated under vacuum, it is possible to suppress the purge gas from being mixed into the lamination interface. Further, by controlling the distance between the lower press plate 174 and the upper press plate 176 during pressing and setting the thickness of the laminate 100 to a predetermined value, it is possible to reduce the volume and the electrolyte resistance. .

  Moreover, since it is a heating press, the first seal portion precursor 114 and the second seal portion precursor 116 are simultaneously cured, so that the manufacturing process can be shortened.

  In the vacuum release process, the vacuum pump 164 is stopped, and the vacuum state of the vacuum chamber 163 is released by opening the leak valve. The upper press plate 176 is raised, and the lid of the vacuum chamber 163 is removed. The cradle 156 of the electrode stocker 150 disposed on the lower press plate 174 is taken out while holding the laminated body 100. Further, parts of the electrode stocker 150 other than the cradle 156 are also taken out.

  In the bipolar battery stack 100, the terminal plates 101 and 102 are then disposed at the uppermost and lowermost positions and accommodated in the outer case 104 (see FIGS. 1 and 2).

  FIG. 18 is a chart for explaining the internal short-circuit test result of the bipolar battery according to the first embodiment.

  The first embodiment and the comparative example were targeted, and evaluation was performed using a voltage measured in the first hour after the completion of the initial charge. The evaluation criterion is the presence or absence of a significant decrease in voltage. The symbols OK and NG represent those that do not have a significant drop in voltage and those that have a voltage, respectively. The numbers are the numbers evaluated as OK or NG when the number of samples is 10. The comparative example is a bipolar battery manufactured without using the manufacturing apparatus according to the first embodiment. The initial charge condition is 4 hours at 21V-0.5C.

  As shown in FIG. 18, the first embodiment is not evaluated as NG, and four comparative examples are NG. Moreover, as a result of conducting a disassembly investigation on the comparative example evaluated as NG, a short circuit due to electrode displacement was confirmed. That is, in the first embodiment, the generation of defective products is suppressed and the yield is improved as compared with the comparative example.

  FIG. 19 is a schematic diagram for explaining a modification according to the first embodiment.

  In order to improve the output density of the battery, it is possible to divide the pressing process into two parts, a first pressing process and a second pressing process, and to insert an initial charging process for removing bubbles generated by the initial charging. The initial charging condition is, for example, 4 hours at 21 V-0.5 C on a capacity basis estimated from the coating weight of the positive electrode.

  In this case, the charge / discharge device 180 is disposed in the vacuum processing device 160. The charging / discharging device 180 is configured to be electrically connected to the stacked body 100 via the lower press plate 174 and the upper press plate 176 of the press means 172.

The pressing condition of the first pressing step is holding for 60 seconds at a surface pressure of 1 kg / cm ² and a normal temperature. The pressing condition of the second pressing step is holding for 1 hour at a surface pressure of 1 kg / cm ² and 80 ° C. In addition, the press conditions of a 1st press process are not specifically limited, Considering the press conditions of a 2nd press process, it sets so that a 1st seal | sticker part precursor and a 2nd seal | sticker part precursor may not harden | cure.

  As described above, the first embodiment can provide a method and an apparatus for manufacturing an electrolyte-based bipolar battery that can achieve a good yield.

  In addition, it is also possible to laminate | stack alternately with a bipolar type electrode (bipolar type | mold battery with no electrolyte layer arrange | positioned) by making an electrolyte layer (separator) into a different body. In this case, the holding mechanism holds the electrolyte layer and the bipolar electrode alternately, and is aligned with respect to the plane direction of the bipolar electrode and the electrolyte layer so that the bipolar electrode and the electrolyte layer are aligned and do not contact each other. And attached to the support structure 154 in a perpendicular direction.

  In addition, the electrode setting process is preferably performed in the atmosphere in consideration of the installation process and the like, but may be performed in a vacuum as necessary.

  It is also possible to have a preheating step for preheating the bipolar battery 110, the laminate 100, or the lower and upper press plates 174, 176 before the pressing step. In this case, it is possible to shorten the time of the pressing process.

  The preheating of the bipolar battery 110 is performed, for example, by placing the entire electrode stocker 150 holding the bipolar battery 110 in an oven and raising the temperature.

  Preheating of the laminated body 100 is performed by, for example, incorporating a heating unit in the cradle 156 on which the laminated body 100 is disposed, and raising the temperature of the cradle 156 by the heating unit. Further, it is also possible to preheat the stacked body 100 by placing the cradle 156 on the lower press plate 174, raising the temperature by the lower heating means 175, and then incorporating it into the electrode stocker 150. .

  The preheating of the lower and upper press plates 174 and 176 is performed, for example, by operating the lower heating means 175 and the upper heating means 177 before the cradle 156 is arranged.

  Next, a second embodiment will be described. In the following, members having the same functions as those in the first embodiment are denoted by similar reference numerals, and the description thereof is omitted to avoid duplication.

  FIG. 20 is a process diagram for explaining the bipolar battery manufacturing method according to the second embodiment.

  The bipolar battery according to Embodiment 2 is a gel polymer electrolyte system, and its manufacturing method includes an electrode formation process, an electrolyte layer formation process, a seal portion precursor formation process, an electrode setting process, a vacuum introduction process, and an electrode lamination process. And a pressing step and a vacuum releasing step.

  Next, each step will be described sequentially. FIG. 21 is a cross-sectional view for explaining the seal portion precursor arranging step shown in FIG. 20, and FIG. 22 is a cross-sectional view for explaining the electrode setting step shown in FIG.

  In the electrode formation step, as in the first embodiment, a bipolar electrode in which the positive electrode 213 and the negative electrode 212 are formed on one surface and the other surface of the current collector 211 (bipolar type in which no electrolyte layer is formed) A battery 210) is obtained.

  In the electrolyte layer forming step, an electrolyte is applied to the electrode portions of the positive electrode 213 and the negative electrode 212.

  The electrolyte has an electrolytic solution [90% by weight] and a host polymer [10% by weight], and has a viscosity suitable for coating by adding a viscosity adjusting solvent.

The electrolytic solution contains an organic solvent composed of PC (propylene carbonate) and EC (ethylene carbonate), and a lithium salt (LiPF ₆ ) as a supporting salt. The lithium salt concentration is 1M.

  The host polymer is PVDF-HFP (copolymer of polyvinylidene fluoride and hexafluoropropylene) containing 10% of HFP (hexafluoropropylene) copolymer. The viscosity adjusting solvent is DMC (dimethyl carbonate).

  The electrolyte applied to the electrode part is dried and the DMC is volatilized to form gel polymer electrolyte layers 218 and 219 on the positive electrode 213 and the negative electrode 212.

  The host polymer is not limited to PVDF-HFP, and other polymers that do not have lithium ion conductivity or polymers that have ion conductivity (solid polymer electrolyte) can also be applied. Other polymers having no lithium ion conductivity are, for example, PAN (polyacrylonitrile) and PMMA (polymethyl methacrylate). Examples of the polymer having ion conductivity include PEO (polyethylene oxide) and PPO (polypropylene oxide). The viscosity adjusting solvent is not limited to DMC.

  In the seal portion precursor forming step, the first seal portion precursor 214, the separator 220, and the second seal portion precursor 216 are arranged as in the first embodiment.

  In the electrode setting step, an electrode stocker 250 having a holding mechanism (clip mechanism 253), a support structure 154, a cradle 156, a position sensor 158, and a control unit (not shown) is used, as in the first embodiment. In addition, six bipolar batteries 210 (210A to 210F) are set in the electrode stocker 250 with the negative electrode face up. Note that the bipolar battery 210F held at the lowest level does not include the gel polymer electrolyte layer 218 on the positive electrode side, the first seal portion precursor 214, the second seal portion precursor 216, and the separator 220.

  In the vacuum introduction process, by using a vacuum processing apparatus having a vacuum unit, a press unit, and a control unit, the electrode stocker holding the bipolar battery 210 is connected to the base of the vacuum chamber as in the first embodiment. When placed in the vacuum chamber, the inside of the vacuum chamber is maintained in a vacuum state.

  In the electrode stacking step, the holding mechanism (clip mechanism 253) and the cradle 256 are relatively moved by a Z-axis moving unit in a direction perpendicular to the surface direction of the bipolar battery 210 under vacuum. Since the relative movement suppresses the shake of the bipolar battery 210, the bipolar battery 210 is stacked with high accuracy.

  Then, when the bipolar battery 210 held by the clip mechanism 253 of the support structure 254 comes into contact with the cradle 256, the drive rod of the clip mechanism 253 is controlled, and the holding of the bipolar battery 210 is canceled.

  On the other hand, when the position sensor 258 detects a positional shift at the time of relative movement of the bipolar battery 210, the XY axis moving means is controlled, and the position in the surface direction of the cradle 256 is adjusted. This further improves the stacking accuracy. Further, since the cradle 256 is not related to the holding mechanism, the movement of the cradle 256 does not affect the position of the bipolar battery 210, and the positional deviation can be easily adjusted.

  Then, by continuing the movement of the support structure 254 with respect to the cradle 256, the bipolar batteries 210F to 210A are sequentially stacked.

  As described above, blurring of the bipolar battery 210 is suppressed, and the bipolar batteries can be stacked with high accuracy. Therefore, the occurrence of displacement between the bipolar electrode and the electrolyte layer constituting the bipolar battery 210 is suppressed, and the occurrence of an internal short circuit can be avoided, so that the occurrence of defective products can be reduced.

  In addition, since the layers are stacked under vacuum, mixing of bubbles with respect to the stack interface between the electrode and the electrolyte layer is suppressed. As a result, a bipolar battery in which mixing of air bubbles is suppressed is obtained, and movement of ions during use is not harmed and battery resistance does not increase, so that a high output density can be achieved.

In the pressing step, the laminated body 200 is heated and pressed while maintaining a vacuum state. The pressing condition is holding for 1 hour at a surface pressure of 1 kg / cm ² and 80 ° C. Accordingly, the first seal portion precursor and the second seal portion precursor are cured, and the first seal and the second seal having a predetermined thickness are formed. Further, the gel polymer electrolyte layers 218 and 219 are plasticized and have a predetermined thickness.

  In addition, since the pressing is performed under heating, the first seal portion precursor 214 and the second seal portion precursor 216 are cured and the gel polymer electrolyte layers 218 and 219 are completed at the same time. be able to.

  In the vacuum releasing step, the vacuum state of the vacuum chamber is released and the stacked body 200 is taken out.

  As described above, Embodiment 2 can provide a gel polymer electrolyte bipolar battery manufacturing method and manufacturing apparatus that can achieve a good yield.

  In addition, the internal short circuit test result of the bipolar battery according to the second embodiment is the same as that of the first embodiment shown in FIG. 18, and the occurrence of defective products is suppressed as compared with the comparative example, and the yield is high. It has improved.

  In addition, since the gel polymer electrolyte layers 218 and 219 are of a thermoplastic type in which an electrolytic solution is held in a polymer skeleton, it is possible to prevent leakage and prevent a liquid junction and constitute a highly reliable bipolar battery. is there. The gel polymer electrolyte is not limited to the thermoplastic type, and a thermoplastic type can also be applied. Also in this case, leakage is prevented and a liquid junction can be prevented.

  Next, a third embodiment will be described.

  FIG. 23 is a process diagram for explaining the manufacturing method of the bipolar battery according to the third embodiment.

  The bipolar battery according to Embodiment 3 is an all-solid electrolyte system, and the manufacturing method thereof includes an electrode forming process, an electrolyte layer forming process, an electrode setting process, a vacuum introducing process, an electrode stacking process, a pressing process, and a vacuum releasing process. Have

  Next, each step will be described sequentially. 24 is a cross-sectional view for explaining the formation of the solid electrolyte layer shown in FIG. 23, FIG. 25 is a cross-sectional view for explaining the formation of the electrode setting step shown in FIG. 23, and FIG. It is the schematic for demonstrating the vacuum processing apparatus which concerns on the form 3.

  In the electrode forming step, first, the positive electrode slurry is adjusted. The positive electrode slurry comprises a positive electrode active material [22% by weight], a conductive auxiliary agent [6% by weight], a polymer [18% by weight], a lithium salt [9% by weight] as a supporting salt, and a slurry viscosity adjusting solvent [45% by weight]. And a small amount of a polymerization initiator.

The positive electrode active material is LiMn ₂ O ₄ . The conductive auxiliary agent is acetylene black. The polymer is polyethylene oxide (PEO). The lithium salt is Li (C ₂ F ₅ SO ₂ ) ₂ N. The slurry viscosity adjusting solvent is NMP. The polymerization initiator is AIBN (azobisisobutyronitrile).

  The positive electrode slurry is applied to one surface of a current collector 311 made of stainless steel foil. The coating film of the positive electrode slurry is held at 110 ° C. for 4 hours using an oven, for example, and cured by thermal polymerization, whereby the positive electrode 313 made of the positive electrode active material layer is formed.

  Next, the negative electrode slurry is adjusted. The negative electrode slurry comprises a negative electrode active material [14% by weight], a conductive auxiliary agent [4% by weight], a polymer [20% by weight], a lithium salt [11% by weight] as a supporting salt, and a slurry viscosity adjusting solvent [51% by weight]. And a small amount of a polymerization initiator.

The negative electrode active material is Li ₄ Ti ₅ O ₁₂ . The conductive auxiliary agent is acetylene black. The polymer is PEO. The lithium salt is Li (C ₂ F ₅ SO ₂ ) ₂ N. The slurry viscosity adjusting solvent is NMP. The polymerization initiator is AIBN.

  The negative electrode slurry is applied to the other surface of the current collector 311. The coating film of the negative electrode slurry is held at 110 ° C. for 4 hours using an oven, for example, and is cured by thermal polymerization, whereby the negative electrode 312 including the negative electrode active material layer is formed.

  As a result, a bipolar electrode in which the positive electrode 313 and the negative electrode 312 are respectively formed on one surface and the other surface of the current collector 311 (bipolar battery 310 without an electrolyte layer) is obtained.

  The bipolar battery 310 is cut to a size of 330 × 250 (mm). The outer peripheral portions of the positive electrode 313 and the negative electrode 312 are peeled off with a width of 10 mm in order to expose the current collector 311.

  In the electrolyte layer forming step, first, a solid electrolyte slurry is prepared. The solid electrolyte slurry contains a polymer [64.5% by weight] and a lithium salt [35.5% by weight] as a supporting salt, and has a predetermined viscosity by a viscosity adjusting solvent.

The polymer is PEO. The lithium salt is Li (C ₂ F ₅ SO ₂ ) ₂ N. The viscosity adjusting solvent is acetonitrile. The polymer is not limited to PEO, and other solid polymer electrolytes (for example, PPO) and inorganic solid electrolytes having ion conductivity such as ceramics can also be applied.

  The solid electrolyte slurry is applied only to the electrode portion of the positive electrode 313. By drying the coating layer of the solid electrolyte slurry, the viscosity adjusting solvent is volatilized, and a 40 μm all solid electrolyte layer 339 is formed. In the all solid electrolyte layer 339, there is no leakage, and a highly reliable bipolar battery can be configured.

  On the other hand, an insulating material 315 is disposed on the outer periphery of the positive electrode side of the bipolar battery 310 where the current collector 311 is exposed. The insulating material 315 is, for example, a polyimide Kapton tape.

  In the electrode setting process, an electrode stocker 350 having a holding mechanism (clip mechanism 353), a support structure 354, a cradle 356, a position sensor 358, and a control unit (not shown) is used, as in the first embodiment. In addition, six bipolar batteries 310 (310A to 310F) are set in the electrode stocker 350 with the negative electrode face up. Note that the bipolar battery 310F held at the lowest level does not include the positive electrode 313, the all solid electrolyte layer 339, and the insulating material 315. The bipolar battery 310 </ b> A held at the top does not have the negative electrode 312.

  In the vacuum introduction process, by using the vacuum processing device 360 having the vacuum means 362, the press means 372, and the control unit 378, the electrode stocker 350 holding the bipolar battery 310 is formed as in the first embodiment. When arranged at the base of the vacuum chamber 363, the inside of the vacuum chamber 363 is maintained in a vacuum state.

  In the electrode stacking step, the holding mechanism (clip mechanism 353) and the cradle 356 are relatively moved by a Z-axis moving unit in a direction perpendicular to the surface direction of the bipolar battery 310 under vacuum. Since the relative movement suppresses the shake of the bipolar battery 310, the bipolar battery 310 is accurately stacked.

  Then, when the bipolar battery 310 held by the clip mechanism 353 of the support structure 354 comes into contact with the cradle 356, the drive rod of the clip mechanism 353 is controlled, and the holding of the bipolar battery 310 is canceled.

  On the other hand, when the position sensor 358 detects a positional shift during the relative movement of the bipolar battery 310, the XY-axis moving means is controlled, and the position in the surface direction of the cradle 356 is adjusted. This further improves the stacking accuracy. Further, since the cradle 356 is not related to the holding mechanism, the movement of the cradle 356 does not affect the position of the bipolar battery 310, and the positional deviation can be easily adjusted.

  Then, by continuing the movement of the support structure 354 with respect to the cradle 356, the bipolar batteries 210F to 210A are sequentially stacked.

  As described above, blurring of the bipolar battery 310 is suppressed, and the bipolar batteries can be stacked with high accuracy. Therefore, the occurrence of displacement between the bipolar electrode and the electrolyte layer constituting the bipolar battery 310 is suppressed and the occurrence of an internal short circuit can be avoided, so that the occurrence of defective products can be reduced.

  In addition, since the layers are stacked under vacuum, mixing of bubbles with respect to the stack interface between the electrode and the electrolyte layer is suppressed. As a result, a bipolar battery in which mixing of air bubbles is suppressed is obtained, and movement of ions during use is not harmed and battery resistance does not increase, so that a high output density can be achieved.

In the pressing step, the laminated body 300 is pressed in a state where a vacuum state is maintained. The pressing condition is holding for 3 minutes at a normal pressure of 1 kg / cm ² . As a result, the negative electrode 312 and the all solid electrolyte layer 339 are in close contact with each other. In the pressing process according to the third embodiment, since no heating press is applied, the lower press plate 374 and the upper press plate 376 of the press unit 372 of the vacuum processing apparatus 360 are not provided with a heating unit. Reference numerals 364 and 365 denote a vacuum pump and a piping system.

  In the vacuum releasing step, the vacuum state of the vacuum chamber 363 is released and the stacked body 300 is taken out.

  As described above, Embodiment 3 can provide a manufacturing method and a manufacturing apparatus of an all-solid electrolyte bipolar battery that can achieve a good yield.

  In addition, the internal short circuit test result of the bipolar battery according to the third embodiment is the same as that of the first embodiment shown in FIG. 18, and the occurrence of defective products is suppressed as compared with the comparative example, and the yield is increased. It has improved. However, initial charge conditions are 4 hours at 12.5V-0.5C. Further, as a result of conducting a disassembly investigation on the comparative example evaluated as NG, a seal failure due to electrode displacement was confirmed.

  The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the claims.

  For example, it is possible to improve the output density of the battery by applying the modification (the first charging step and the charging / discharging device) according to the first embodiment to the second and third embodiments. The initial charging condition according to Embodiment 3 is, for example, a capacity base estimated from the coating weight of the positive electrode and is 2.5 V-0.5 C for 4 hours.

  Hereinafter, the present invention will be described in detail using examples.

Examples 1 to 10 and Comparative Examples 1 to 3
(I) Production process of bipolar secondary battery <Production of bipolar electrode>
1. Formation of Positive Electrode The following materials were mixed at a predetermined ratio to produce a positive electrode slurry. Specifically, a positive electrode active material, a conductive additive, and a binder were added and mixed in predetermined amounts (see Tables 1A to 1C) until the viscosity became optimum for the coating process using NMP to prepare a positive electrode slurry. In all of the examples and comparative examples, acetylene black was used as the conductive auxiliary agent and PVdF was used as the binder.

  Next, the positive electrode slurry was applied to one side of a current collector having a thickness of 15 μm (see Tables 1A to 1C) and dried to form a positive electrode having an electrode layer having a thickness of 30 μm.

2. Formation of Negative Electrode The following materials were mixed at a predetermined ratio to prepare a negative electrode slurry. Specifically, a negative electrode active material, a conductive auxiliary agent, and a binder were added and mixed in predetermined amounts (see Tables 1A to 1C) until the viscosity became optimum for the coating process using NMP to prepare a negative electrode slurry. In all of the examples and comparative examples, acetylene black was appropriately used as the conductive additive and PVdF was appropriately used as the binder.

  Next, the negative electrode slurry was applied to the opposite surface of the current collector on which the positive electrode was formed and dried to form a negative electrode having a 30 μm thick electrode layer. At this time, the positive electrode area and the negative electrode area were the same, and the positive electrode and the negative electrode were formed by adjusting the positive electrode and the negative electrode so that projections onto the current collector coincided with each other.

3. Production of Bipolar Electrode A bipolar electrode was formed by forming a positive electrode and a negative electrode on both sides of the current collector. These bipolar electrodes were cut into a length of 330 mm and a width of 250 mm, and the outer surface of both the positive electrode and the negative electrode was peeled off by 20 mm to expose the surface of the current collector. As a result, a bipolar electrode having an electrode surface of 290 mm long × 210 mm wide and having a current collector of 20 mm exposed on the outer peripheral portion was produced (see FIGS. 6 to 8).

<Formation of electrolyte layer>
The following materials were mixed at a predetermined ratio to produce an electrolyte material.

Polyvinylidene fluoride-hexafluoropropylene copolymer (PVdF) containing propylene carbonate (PC) containing 1.0 M LiPF ₆ +90 wt% of ethylene carbonate (EC) (1: 1) as an electrolyte and 10% of HFP component as a host polymer -HFP) 10 wt% and, as a viscosity adjusting solvent, dimethyl carbonate (DMC) was mixed until the viscosity became optimum for the coating process to prepare a pregel electrolyte.

  This pregel electrolyte was applied to the positive and negative electrode portions on both sides of the bipolar electrode formed in advance, and the DMC was removed by drying under vacuum and dried to complete the bipolar electrode soaked with the gel electrolyte (FIG. 6). ~ 8).

<Formation of seal part precursor>
Using a dispenser on the electrode-unapplied portion in the periphery of the positive electrode of the bipolar electrode obtained above, the first seal portion precursor (one liquid) is formed on the outer periphery (all four sides) of the positive electrode as shown in FIGS. Non-cured epoxy resin).

  Next, a polyethylene separator having a length of 340 mm and a width of 260 mm (thickness: 12 μm; hereinafter also referred to as a spacer) was installed on the positive electrode side of the bipolar electrode provided with the first seal portion precursor so as to cover the entire current collector. .

  Then, from the top of the spacer, using a dispenser on the electrode non-applied portion (the same portion as the portion where the first seal portion precursor is applied), the outer peripheral portion of the positive electrode as shown in FIGS. The second seal portion precursor (one-component uncured epoxy resin) was applied to all four sides.

  Here, it is applied in several times as necessary so that the second seal portion precursor is located inside the separator (impregnation) and above it (position corresponding to the electrode non-applied portion of the electrode outer peripheral portion). May be. However, since the first or second seal portion precursor can be impregnated and cured inside the separator during the hot press treatment described later, it is not necessary to impregnate the separator during the application. The application position of the second seal portion precursor was the same as the portion where the first seal portion precursor was applied (position facing the spacer). That is, the first seal portion precursor and the second seal portion precursor are formed by adjusting the projections of the first seal portion precursor and the second seal portion precursor onto the current collector (or separator) to coincide with each other. did.

<Set to electrode holding mechanism>
With the bipolar electrode created above, with the negative electrode face up, the electrodes do not contact and do not shift in the direction perpendicular to the electrode surface direction. Six sets of bipolar electrode holding mechanisms (support structures) having a clip mechanism capable of chucking the outside were set (see FIGS. 22, 14, and 25). Of these, the bottom bipolar electrode uses a seal portion (first and second seal portion precursors) and a separator (spacer), and the gel electrolyte is not applied to the positive electrode surface. It was. The top bipolar electrode used was one in which the gel electrolyte was not applied to the negative electrode surface. The other four bipolar electrodes were provided with a seal portion (first and second seal portion precursors) and a separator (spacer), and the gel electrolyte was not applied to the positive electrode surface and the negative electrode surface. .

<Introduction to vacuum>
The electrode holding mechanism was introduced into a vacuum chamber having a laminated portion and a pressurizing / heating press portion, and the vacuum chamber was evacuated by a vacuum pump (see FIGS. 19, 15, and 26).

<Lamination of electrodes>
While the above-mentioned electrode holding mechanism (support structure) in the vacuum chamber is lowered, the six bipolar electrodes are stacked on the electrode base so as not to be displaced (see FIG. 16). A laminated bipolar battery structure (laminated body) was produced.

<Bipolar battery press>
The bipolar battery structure (laminated body) is moved to the press site together with the electrode base in a vacuum, and the gel electrolyte is plasticized by hot pressing with a hot press machine at a surface pressure of 1 kg / cm ² and 80 ° C. for 1 hour. The distance between the electrodes (between the positive electrode and the negative electrode) was pressed to the thickness of the separator, and at the same time, the uncured seal portion (first and second seal portion precursors; one-component uncured epoxy resin) was cured. This step makes it possible to press and cure the seal portion to a predetermined thickness (see FIG. 17). Further, the separator is impregnated with the plasticized gel electrolyte by the hot press treatment. Thereby, while holding a gel electrolyte inside an electrode, the electrolyte layer which contains a gel electrolyte also in the said separator inside can be completed.

  That is, in the previous electrolyte layer forming step, the electrode is formed in the above electrolyte layer so that the gel electrolyte can be held inside the electrode and the electrolyte layer containing the gel electrolyte can be formed inside the separator. The amount of the pregel electrolyte applied may be adjusted.

<Removal from vacuum chamber>
After the inside of the vacuum chamber was leaked and returned to atmospheric pressure, the bipolar battery structure (laminated body) was taken out to complete a gel electrolyte type bipolar battery (see FIG. 17).

  The batteries of Examples 1 to 10 and Comparative Examples 1 to 3 were manufactured through the above steps.

<Evaluation>
A charge / discharge test was performed on the batteries of Examples 1 to 10 and Comparative Examples 1 to 3. In the experiment, constant current (CC) charging was performed until each battery was fully charged (see Tables 1A to 1C) with a current of 100 mA, and then charging was performed with a constant voltage (CV) for 10 hours.

  Thereafter, these batteries were charged with a constant current (CC) at a current of 100 mA, then discharged with a constant current (CC), and this cycle was repeated at 55 ° C. (cycle test).

  The following Tables 2A to 2C show the results of the cycle test. The number of cycles was determined to be the end of the cycle when the capacity reached 60%.

  Comparing the results of Comparative Examples 1-3, Comparative Example 1 has better cycle characteristics than Comparative Examples 2-3, and durability is improved by using stainless steel 316L. This is considered to be attributable to the fact that Cu as a current collector was eluted in Comparative Example 2. In Comparative Example 3, it is considered that the current collector Al is alloyed with Li.

  However, also in Comparative Example 1, the voltage suddenly decreased at the 132nd cycle. Therefore, even if the current collector shown in Patent Document 1 (Japanese Patent Laid-Open No. 2001-236946) is made of stainless steel as an alloy (this time, it is SUS316L, the best mode described in Patent Document 1). Problems arise when the number of cycles increases. When the battery after the cycle is dismantled, a pinhole is considered to be caused by corrosion (pitting corrosion) on the positive electrode side of the current collector SUS316L. It is done.

  When Examples 1 to 3, 5, and 10 are compared with Comparative Example 1, Examples 1 to 3 have an increased number of cycles. Although the detailed mechanism is not clear from this result, it is considered that the working potential on the positive electrode side can be lowered by using the olivine positive electrode, and the occurrence of corrosion is suppressed. It is considered that the working potential on the positive electrode side can be lowered by using the olivine positive electrode, and the occurrence of corrosion is suppressed. In Examples 3, 5, and 10, it can be seen that SUS304, which is relatively inexpensive, is effective.

  When Examples 6 to 10 are compared with Comparative Example 1, Examples 6 to 10 have a further increased number of cycles. Although the detailed mechanism is not clear from this result, the operating potential on the negative electrode side can be increased by using lithium titanate, and is considered to prevent alloying with Li. From Example 6, Example 9, and Example 10, it can be confirmed that various positive electrode materials can be combined with the lithium titanate negative electrode. Further, when the weights of the batteries of Examples 8 to 10 and the batteries of Examples 1 to 3 were compared, the batteries of Examples 8 to 10 were 1/2 weight. This is considered to be because Al can be used as a current collector material, and it was confirmed that the output density and the capacity density were improved.

  When Example 4 and Comparative Example 1 are compared, it can be seen that the number of cycles is improved by using titanium for the current collector. Moreover, even when the weight was compared, it was 2/3 for titanium, and it was confirmed that the power density and the capacity density were improved.

  The elution potential and Li alloying potential of the current collectors used in the batteries of Examples 1 to 10 and Comparative Examples 1 to 3 are shown in Table 3, the redox potentials of the positive electrode and the negative electrode are shown in Table 4, and each example. Tables 5A to 5C show the oxidation-reduction potential of the positive electrode and the negative electrode, the elution potential of the current collector, and the Li alloying potential.

Note) With the elution potentials in Tables 3 and 5 above, the breakdown of the electrolyte [= EC-DEC (1: 1) 1M LIPF ₆ ] occurred before the current collector eluted. Since the measurement was difficult, the measurement was stopped. For such current collector species, at least the elution potential of the current collector is equal to or higher than the decomposition potential (= 6 V) of the electrolyte solution. Therefore, in Tables 3 and 5, the elution potential of the current collector is 6 V or higher. (More than electrolyte decomposition). Further experiments can be performed by changing to an electrolyte species having a high decomposition potential of the electrolyte. However, as shown in Table 5, since the redox potentials of the positive electrodes were all 4.2 V or less, such an experiment was performed. Thus, since it has become clear that at least the oxidation-reduction potential of the positive electrode active material is lower than the elution potential of the current collector, no further elution potential measurement experiment was performed.

  Similarly, with respect to the Li alloying potentials in Tables 3 and 5 above, when the oxidation-reduction potential of the current collector is first applied and a current flows at the applied voltage, the applied voltage is gradually reduced to reduce the current. The voltage that stopped flowing was set as the Li alloying potential, but in the voltage range (minimum applied voltage 0 V) that can be applied by the measuring instrument, the current continued to flow, and the Li alloying potential could not be specified (Li precipitation progressed). The measurement was stopped. For these current collector types, at least the Li alloying potential of the current collector is equal to or lower than the minimum applied voltage (= 0 V). Therefore, Table 3 and Table 5 show the Li alloying potential of the current collector. 0 V or less (Li precipitation proceeds). Although further experiments can be performed by changing the measuring instrument to one that can measure to a lower voltage, as shown in Table 5, the redox potentials of the negative electrodes were both 0.05 V or higher. Since this experiment clearly shows that at least the redox potential of the negative electrode active material is higher than the Li alloying potential of the current collector, no further experiment for measuring the Li alloying potential was performed.

BRIEF DESCRIPTION OF THE DRAWINGS It is the cross-sectional schematic which represented typically the outline | summary of the bipolar lithium ion secondary battery which is one typical embodiment of the bipolar secondary battery of this invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view schematically showing an appearance of a stacked flat bipolar secondary battery that is a typical embodiment of a bipolar secondary battery according to the present invention.

FIG. 3A is an external view schematically showing a typical embodiment of a battery pack according to the present invention, FIG. 3A is a plan view of the battery pack, FIG. 3B is a front view of the battery pack, and FIG. It is a side view of a battery. It is a conceptual diagram of the vehicle carrying the assembled battery of this invention. FIG. 5 is a process diagram for explaining a manufacturing method of the bipolar battery (electrolyte-based bipolar battery) according to Embodiment 1. It is a front view for demonstrating the positive electrode which concerns on the electrode formation process shown by FIG. It is a rear view for demonstrating the negative electrode which concerns on the electrode formation process shown by FIG. It is sectional drawing regarding line VIII-VIII of FIG. It is a front view for demonstrating the 1st seal | sticker part precursor of the seal | sticker part precursor arrangement | positioning process shown by FIG. It is sectional drawing regarding line XX of FIG. It is a front view for demonstrating the 2nd seal | sticker part precursor of the seal | sticker part precursor arrangement | positioning process shown by FIG. It is sectional drawing regarding the line XII-XII of FIG. It is the schematic for demonstrating the clip mechanism of the holding mechanism which concerns on the electrode setting process shown by FIG. It is sectional drawing for demonstrating an electrode setting process. It is the schematic for demonstrating the vacuum processing apparatus which concerns on the vacuum introduction process-vacuum release process shown by FIG. It is the schematic for demonstrating the electrode lamination process shown by FIG. It is sectional drawing for demonstrating the press process shown by FIG. 4 is a chart for explaining the internal short-circuit test result of the bipolar battery according to Embodiment 1. FIG. FIG. 6 is a schematic diagram for explaining a modified example according to the first embodiment. FIG. 5 is a process diagram for explaining a manufacturing method of a bipolar battery (gel polymer electrolyte bipolar battery) according to a second embodiment. It is sectional drawing for demonstrating the seal | sticker part precursor arrangement | positioning process shown by FIG. It is sectional drawing for demonstrating the electrode setting process shown by FIG. FIG. 5 is a process diagram for explaining a method for manufacturing a bipolar battery (all solid electrolyte bipolar battery) according to Embodiment 3. It is sectional drawing for demonstrating formation of the solid electrolyte layer shown by FIG. FIG. 24 is a cross-sectional view for explaining the formation of the electrode setting step shown in FIG. 23. FIG. 6 is a schematic diagram for explaining a vacuum processing apparatus according to a third embodiment.

Explanation of symbols

10 Bipolar secondary battery,
11 Current collector,
11a The outermost layer current collector on the positive electrode side,
11b The outermost layer current collector on the negative electrode side,
13 positive electrode (positive electrode active material layer),
15 negative electrode (negative electrode active material layer),
16, 16a, 16b bipolar electrode,
17 electrolyte layer (gel electrolyte layer),
17a separator (electrolyte non-application part),
19 single battery layer (= battery unit or single cell),
21 battery element (bipolar battery structure; laminate),
25 positive electrode tab,
27 negative electrode tab,
29 Battery exterior materials (eg laminate films),
31 seal part,
31a Seal part precursor (one-component uncured epoxy resin),
35 A small assembled battery that can be attached and detached,
37 battery pack,
39 Connecting jig,
40 electric car,
100 laminates,
101,102 terminal plate,
104 exterior case,
110 (110A to 110F) bipolar electrode (bipolar battery without an electrolyte layer),
111 current collector,
112 negative electrode,
113 positive electrode,
114 first seal portion precursor,
115 first seal,
116 second seal portion precursor,
117 second seal,
120 separator,
150 electrode stocker,
153 clip mechanism,
154 support structure,
156 cradle,
158 position sensor,
160 vacuum processing equipment,
162 vacuum means,
163 vacuum chamber,
164 vacuum pump,
165 piping system,
172 pressing means,
174 Lower press plate,
175 Lower heating means,
176 Upper press plate,
177 Upper heating means,
178 controller,
180 charging / discharging device,
191 Lower arm,
192 Lower step,
193 Upper arm,
194 second upward inclined portion,
195 guide block,
196 through hole,
197 movable block,
198 Drive rod,
200 laminates,
210 Bipolar secondary battery,
210 (210A to 210F) bipolar electrode (bipolar battery with no electrolyte layer formed),
211 current collector,
212 negative electrode,
213 positive electrode,
214 first seal portion precursor,
216 second seal portion precursor,
218, 219 Gel polymer electrolyte layer,
220 separator,
250 electrode stocker,
253 clip mechanism,
254 support structure,
256 cradle,
258 position sensor,
300 laminates,
310 (310A-310F) bipolar electrode (bipolar battery with no electrolyte layer formed),
311 current collector,
312 negative electrode,
313 positive electrode,
315 insulating material,
339 all solid electrolyte layer,
350 electrode stocker,
353 clip mechanism,
354 support structure,
356 cradle,
358 position sensor,
360 vacuum processing equipment,
362 vacuum means,
363 vacuum chamber,
364 vacuum pump,
365 piping system,
372 press means,
374 Lower press plate,
376 Upper press plate,
378 control unit.

Claims (16)

A positive electrode electrically coupled to one surface of the current collector, a negative electrode electrically coupled to the opposite surface of the current collector, and an electrolyte layer disposed therebetween, the alternating layers In the bipolar secondary battery stacked in
The redox potential of the positive electrode active material of the positive electrode is lower than the elution potential of the current collector, and the redox potential of the negative electrode active material of the negative electrode is higher than the lithium alloying potential of the current collector. A bipolar secondary battery characterized by that.   The bipolar secondary battery according to claim 1, wherein an olivine-based positive electrode material is used as the positive electrode active material.   The bipolar secondary battery according to claim 1 or 2, wherein carbon or a lithium-transition metal composite oxide is used as the negative electrode active material.   The current collector is made of at least one current collector material selected from the group consisting of iron, chromium, nickel, manganese, titanium, molybdenum, vanadium, niobium, copper, silver, gold, and carbon. The bipolar secondary battery according to any one of claims 1 to 3, wherein an electric body is used.   The bipolar secondary battery according to claim 1, wherein lithium titanate is used as the negative electrode active material.   6. The bipolar secondary battery according to claim 5, wherein a lithium-transition metal composite oxide is used as the positive electrode active material.   The current collector is made of at least one current collector material selected from the group consisting of iron, chromium, nickel, manganese, titanium, molybdenum, vanadium, niobium, silver, gold, platinum and aluminum. The bipolar secondary battery according to claim 5 or 6, wherein an electric body is used.   The bipolar secondary battery according to claim 7, wherein pure aluminum is used as a material for the current collector.   The bipolar secondary battery according to claim 1, wherein titanium is used as a material of the current collector.   The bipolar secondary battery according to claim 9, wherein a lithium-transition metal composite oxide is used as the positive electrode active material.   The bipolar secondary battery according to claim 10 or 11, wherein carbon or a lithium-transition metal composite oxide is used as the negative electrode active material.   The bipolar secondary battery according to any one of claims 1 to 11, wherein the bipolar secondary battery is configured to cover at least all electrode projection surfaces of the positive electrode and the negative electrode end electrode with a highly conductive tab and further cover with an outer case.   The bipolar secondary battery according to claim 1, wherein the electrolyte layer is a gel polymer electrolyte layer.   The bipolar secondary battery according to claim 1, wherein the electrolyte layer is an all solid electrolyte layer.   An assembled battery comprising a plurality of the bipolar secondary batteries according to claim 1 connected to each other.   A vehicle equipped with the bipolar secondary battery according to any one of claims 1 to 14 and / or the assembled battery according to claim 15 as a driving power source.

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