JP2007026725A - Lithium ion secondary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lithium ion secondary battery having higher output and capacity by sucking (absorbing) gas trapped by an electrode active substance layer/electrolyte layer interface and an electrode active substance layer/collector interface causing an output drop. <P>SOLUTION: In the lithium ion secondary battery in a structure; an electrode in which a positive electrode active substance layer is provided at one collector, and a negative electrode active substance layer is provided at the other through an electrolyte layer. An active substance layer containing gas adsorbent is formed on at least one surface of the active substance layer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a lithium ion secondary battery.

  Lithium ion secondary battery has a problem that gas generation occurs during the initial charge and long-term use of the battery, and trapped at the interface between the electrode and the electrolyte layer or the electrode and the current collector, reducing the contact area and making it difficult to obtain high output Met. As a countermeasure, gas has been removed by sealing under vacuum during the battery sealing process. Further, gas absorption and moisture absorption have been performed by adding an adsorbent to the entire electrode active material layer.

  However, in a bipolar (bipolar) type lithium ion secondary battery using a polymer electrolyte or gel electrolyte as an electrolyte layer, the generated gas is difficult to move at the electrode active material layer / electrolyte layer, electrode active material layer / current collector interface. I get trapped. Therefore, the conventional method as described above cannot completely degas and the gas remains in the battery cell, and when the adsorbent is added to the entire active material layer, the amount of active material is reduced, and the reaction surface area, battery There was a problem that capacity decreased.

  Therefore, the present invention absorbs (adsorbs) the gas trapped at the electrode active material layer / electrolyte layer interface and the electrode active material layer / current collector interface, which causes a decrease in the output, and has a higher output and a higher capacity lithium. An object is to provide an ion secondary battery.

An object of the present invention is to provide a lithium battery having a structure in which a positive electrode active material layer is provided on one current collector and a pair of electrodes provided with a negative electrode active material layer is provided on the other current collector via an electrolyte layer. In ion secondary batteries,
This can be achieved by a lithium ion secondary battery in which an active material layer containing a gas adsorbent is formed on at least one surface of the active material layer.

  In the present invention, when an active material layer not containing a gas adsorbent and an active material layer containing a gas adsorbent are arranged on at least one of the positive and negative electrodes, the gas adsorbent performs degassing when the battery is sealed. In addition, the gas trapped at the interface between the active material layer and the electrolyte layer or the current collector interface can be absorbed (adsorbed). Further, the gas adsorbent is generated inside the battery at the time of initial charge or when the battery is used for a long time, and the gas that is trapped at the interface between the active material layer and the electrolyte layer or the current collector and cannot move can be adsorbed. As a result, a gas that could not be removed in the battery can be adsorbed, the internal resistance of the battery can be reduced, and a lithium ion secondary battery with higher output and higher capacity can be provided.

  In the lithium ion secondary battery of the present invention, one current collector is provided with a positive electrode active material layer, and the other current collector is provided with a negative electrode active material layer (a pair of electrodes) via an electrolyte layer. In a lithium ion secondary battery having a structure, an active material layer containing a gas adsorbent (hereinafter also simply referred to as a gas adsorbent-containing active material layer) is formed on at least one surface of the active material layer. To do. Therefore, on one surface of the active material layer, a layer that does not contain an active material and contains a gas adsorbent (also simply referred to as a gas adsorbent single-containing layer) may be formed. In the present invention, the gas adsorbent-containing active material layer and the gas adsorbent single-containing layer are collectively referred to as a gas adsorbent-containing layer.

  First, the structure (arrangement configuration) of an active material layer formed by forming an active material layer containing a gas adsorbent, which is a characteristic part of the present invention, will be described with reference to the drawings.

  FIG. 1A is a schematic cross-sectional view schematically showing a unit cell structure when a gas adsorbent-containing active material layer is provided at the active material layer / electrolyte layer interface. FIG. 1B is a schematic cross-sectional view schematically showing a unit cell structure when a gas adsorbent-containing active material layer is provided at the active material layer / current collector interface. FIG. 1C is a schematic cross-sectional view schematically showing a unit cell structure when the gas adsorbent-containing active material layer is provided at both the active material layer / electrolyte layer interface and the active material layer / current collector interface. FIG. FIG. 2 schematically shows an electrode laminate (bipolar battery main body) of a bipolar flat type (laminated type) lithium ion secondary battery obtained by laminating three cell structures of FIG. 1A. FIG. In the present invention, unless otherwise specified, the interface between the active material layer and the electrolyte layer is abbreviated as “active material layer / electrolyte layer interface”, and the interface between the active material layer and the current collector is referred to as “active material layer / electrolyte layer”. This is abbreviated as “current collector interface”.

  1A to 1C show an embodiment in which a gas adsorbent-containing active material layer is formed on each of the positive electrode active material layer side and the negative electrode active material layer side. In the present invention, such an embodiment is used. It is not limited. That is, the gas adsorbent-containing active material layer may be formed only on either the positive electrode active material layer side or the negative electrode active material layer side. Preferably, it is desirable to form at least a gas adsorbent-containing active material layer on the positive electrode active material layer side where a large amount of gas generation is observed during initial charge and long-term use, and more desirably, the positive electrode active material layer and the negative electrode active material It can be said that it is more desirable to form a necessary amount of the gas adsorbent-containing active material layer in each of the layers based on the amount of gas generated during the initial charge and long-term use.

  The present invention is characterized in that a gas adsorbent-containing active material layer is formed on at least one surface of the active material layer. This point will be described separately in first to third embodiments.

(A) 1st form Here, since it is desirable to arrange | position a gas adsorbent containing active material layer in the gas vicinity generate | occur | produced in the active material layer / electrolyte layer interface, it is gas on the surface which contacts the electrolyte layer of an active material layer. It can be said that it is desirable to form the adsorbent-containing active material layer (hereinafter also referred to as a first embodiment). In such a first embodiment, without reducing the battery capacity, the gas accumulated at the electrode / electrolyte interface that could not be removed in the battery sealing step can be adsorbed and the internal resistance of the battery can be reduced ( Refer to the comparison between “resistance value / comparative example 1 resistance value” and “capacitance value / comparative example 1 capacitance value” in Example 1 and Comparative Example 1.

  In the first embodiment, since it is more effective that the gas adsorbent-containing active material layer also includes an electrode active material, the active material layer includes an active material layer containing no gas adsorbent and an active material layer / electrolyte. It is desirable to adopt a structure in which an active material layer containing a gas adsorbent is provided at the layer interface. Specifically, as shown in FIG. 1A, in the single cell layer 11, the positive electrode active material layer 13 and the negative electrode active material layer 15 which are adjacent (a pair of) electrodes with the electrolyte layer 14 interposed therebetween are opposed to each other. It is like that. The positive electrode active material layer 13 and the negative electrode active material layer 15 are both on the current collector 12, active material layers 13 a and 15 a not containing a gas adsorbent, and an active material layer 13 b containing a gas adsorbent thereon. It has a two-layer structure in which 15b are laminated in order. That is, in the first embodiment, both the positive electrode active material layer 13 and the negative electrode active material layer 15 are such that the gas adsorbent-containing active material layers 13b and 15b are formed at the active material layer / electrolyte layer interface.

  In the first embodiment having such a structure, the gas adsorbent is generated at the time of first charge / discharge and the battery is used for a long time without adhering to the active material layer / current collector interface without causing a decrease in battery capacity. Excellent in that it can be done. In addition, the application | coating method of each layer has the application | coating by a self-propelled die coater, the application | coating by an inkjet type | mold, etc. (The manufacturing method of a battery is mentioned later).

(B) Second embodiment Since the gas adsorbent-containing active material layer is preferably disposed in the vicinity of the gas generated at the active material layer / current collector interface, the gas adsorbed on the surface of the active material layer in contact with the current collector It can be said that it is desirable to form the adsorbent-containing active material layer (hereinafter also referred to as a second embodiment). In the second embodiment, without reducing the battery capacity, the gas accumulated at the electrode / electrolyte interface that could not be removed in the battery sealing step can be adsorbed and the internal resistance of the battery can be reduced ( Refer to the comparison of “resistance value / comparative example 1 resistance value” and “capacitance value / comparative example 1 capacitance value” in Example 6 and Comparative Example 1.)

  In the second embodiment, since it is more effective that the gas adsorbent-containing active material layer also includes an electrode active material, the active material layer includes an active material layer not containing a gas adsorbent and an active material layer / collector. It is desirable to adopt a structure in which an active material layer containing a gas adsorbent is provided at the electrical interface. Specifically, as shown in FIG. 1B, the single cell layer 11 is configured such that the positive electrode active material layer 13 and the negative electrode active material layer 15 of the adjacent electrodes sandwiching the electrolyte layer 14 face each other. . The positive electrode active material layer 13 and the negative electrode active material layer 15 are both on the current collector 12, active material layers 13 b and 15 b containing a gas adsorbent, and an active material layer 13 a containing no gas adsorbent thereon. It has a two-layer structure in which 15a is laminated in order. That is, in the second embodiment, both the positive electrode active material layer 13 and the negative electrode active material layer 15 are such that the gas adsorbent-containing active material layers 13b and 15b are formed at the active material layer / current collector interface.

  In the second embodiment having such a structure, the gas adsorbent is adsorbed on the active material layer / electrolyte interface and cannot move due to the gas adsorbent generated during the first charge / discharge and the battery for a long time without causing a decrease in battery capacity. It is excellent in that it can. In addition, the application | coating method of each layer has the application | coating by a self-propelled die coater, the application | coating by an inkjet type | mold, etc. (The manufacturing method of a battery is mentioned later).

(C) Third Embodiment Since the gas adsorbent-containing active material layer is desirably disposed in the vicinity of the gas generated at the active material layer / electrolyte interface and the active material layer / current collector interface, the electrolyte of the active material layer It is desirable that the gas adsorbent-containing active material layer be formed on both the surface in contact with the layer and the surface of the active material layer in contact with the current collector (hereinafter also referred to as the third embodiment). In the third embodiment, the battery internal resistance can be adsorbed on the electrode / electrolyte interface and the electrode / current collector interface that could not be removed in the battery sealing step without causing a decrease in battery capacity. (Refer to “resistance value / comparative example 1 resistance value” and “capacitance value / comparative example 1 capacitance value” in Example 7 and Comparative Example 1 in Table 1).

  Also in the third embodiment, since it is more effective that the gas adsorbent-containing active material layer also contains an electrode active material, the active material layer includes an active material layer containing no gas adsorbent and an active material layer / It is desirable to adopt a structure in which an active material layer containing a gas adsorbent is provided at the current collector interface. Specifically, as shown in FIG. 1C, the single cell layer 11 is configured such that the positive electrode active material layer 13 and the negative electrode active material layer 15 of the adjacent electrodes sandwiching the electrolyte layer 14 face each other. . The positive electrode active material layer 13 and the negative electrode active material layer 15 are both on the current collector 12, active material layers 13 b and 15 b that are not gas adsorbent-containing active material layers, and an active material layer 13 a that does not contain a gas adsorbent thereon. , 15a, and further, active material layers 13b, 15b containing a gas adsorbent thereon are stacked in order. That is, in the third embodiment, the gas adsorbent-containing active material layers 13b and 15b are formed at the active material layer / electrolyte interface and the active material layer / current collector interface in both the positive electrode active material layer 13 and the negative electrode active material layer 15. Has been.

  In the third embodiment, the gas adsorbent is generated during the first charge / discharge or long-term use of the battery without causing a decrease in battery capacity, and cannot be accumulated in the active material layer / electrolyte interface and the active material layer / electrolyte interface. It is excellent in that it can be adsorbed. In addition, the application | coating method of each layer has the application | coating by a self-propelled die coater, the application | coating by an inkjet type | mold, etc. (The manufacturing method of a battery is mentioned later).

  In the lithium ion secondary battery according to the present invention, for example, as shown in FIG. 2, electrodes having the same stacked structure of active material layers on the positive electrode active material layer 13 side and the negative electrode active material layer 15 side (for example, FIG. An electrode laminate (battery body) 21 having a structure in which a plurality of 1 (A) electrodes) are laminated with the electrolyte layer 14 interposed therebetween can be formed. However, in the present invention, the laminated structure of the active material layer may be different between the positive electrode active material layer side and the negative electrode active material layer side. For example, the positive electrode active material layer side has the stacked structure of the electrode active material layer of FIG. 1A, and the negative electrode active material layer side has the structure shown in FIG. B) or the laminated structure of the electrode active material layers shown in FIG. Similarly, the positive electrode active material layer side has the stacked structure of the electrode active material layer of FIG. 1B, and the negative electrode active material layer side of FIG. 1B other than the stacked structure of the electrode active material layer of FIG. A laminated structure of the electrode active material layer of A) or FIG. Further, the positive electrode active material layer side has the stacked structure of the electrode active material layer in FIG. 1C, and the negative electrode active material layer side has the structure other than the stacked structure of the electrode active material layer in FIG. ) Or the stacked structure of the electrode active material layers shown in FIG. Furthermore, in the present invention, an electrode structure in which the gas adsorbent-containing active material layer of the present invention as shown in the above first to third embodiments is formed only on either the positive electrode active material layer side or the negative electrode active material layer side. It is good. Moreover, it is good also as a different electrode structure for every single battery layer (single cell) which comprises a battery. However, the present invention is not limited to the laminated structure of these electrode active material layers.

  Further, the gas adsorbent-containing active material layer is described as a part of the active material layer for convenience, but it goes without saying that the gas adsorbent-containing active material layer may be regarded as an independent layer different from the normal active material layer. Moreover, you may catch as a part of electrolyte layer or a part of electrical power collector. Such cases should also be understood as being included in the technical scope of the present invention, and should not be regarded as different inventions depending on which one they belong to.

  Next, the overall configuration of the lithium ion secondary battery according to the present invention and the components will be described separately.

  First, since the lithium ion secondary battery according to the present invention can have a higher output and a higher capacity, it can be suitably used for a drive power source of a vehicle, and also as a lithium ion secondary battery for portable devices such as a mobile phone. Is also fully applicable. In other words, the lithium ion secondary battery that is the subject of the present invention is only required to have a gas adsorbent-containing active material layer formed on at least one surface of the active material layer. It should not be restricted. For example, when the lithium ion secondary battery is distinguished by form / structure, it can be applied to any conventionally known form / structure such as a stacked (flat) battery or a wound (cylindrical) battery. Is. That is, “a structure in which (a pair of) electrodes are interposed via an electrolyte layer” is interpreted in the broadest sense including both the stacked (flat) battery and the wound (cylindrical) battery. It is for getting. Therefore, the requirement should not be intentionally interpreted narrowly. In addition, when viewed in terms of electrical connection form (electrode structure) in a lithium ion secondary battery, it is not a bipolar type (internal parallel connection type) battery or a bipolar type (internal series connection type) battery. It can be applied. That is, it is not these bipolar types that “a pair of electrodes in which one current collector is provided with a positive electrode active material layer and the other current collector is provided with a negative electrode active material layer” (internal This is intended to be interpreted in the broadest sense, including both forms of a parallel connection type battery and a bipolar type (internal series connection type) battery. Therefore, the requirement should not be intentionally interpreted narrowly. A battery that is not a bipolar type has a higher cell voltage than a normal battery, and can have a high capacity and output characteristics. When distinguished by the type of electrolyte (layer) in the lithium ion secondary battery, a solution electrolyte type battery using a solution electrolyte such as a non-aqueous electrolyte as the electrolyte (layer), or a polymer electrolyte as the electrolyte (layer) A polymer battery using a polymer battery (the polymer battery is a gel electrolyte battery using a polymer gel electrolyte (also simply referred to as gel electrolyte), a solid polymer using a polymer solid electrolyte (also simply referred to as polymer electrolyte) (all It can be applied to any conventionally known electrolyte (layer). Among them, polymer batteries, especially solid polymer (all solid) batteries, do not leak, so that there is no problem of liquid junction, high reliability, and a simple configuration with excellent output characteristics. It is advantageous in that it can. In addition, by adopting a laminated (flat) battery structure, long-term reliability can be secured by a sealing technique such as simple thermocompression bonding, which is advantageous in terms of cost and workability.

  Therefore, in the following description, a non-bipolar type lithium ion secondary battery using the gas adsorbent-containing active material layer of the present invention and a bipolar type lithium ion secondary battery will be described very simply with reference to the drawings. It should never be restricted to these.

  FIG. 3 is a schematic cross-sectional view of a flat (stacked) lithium ion secondary battery that is not a bipolar type. In the lithium ion secondary battery 31 shown in FIG. 3, the power generation element 38 is formed by joining all of the peripheral part by thermal fusion using a laminate film in which a polymer-metal is combined with the battery exterior material 32. Contained and sealed. Here, the power generation element 38 includes a positive electrode plate in which a positive electrode active material layer 34 provided with a gas adsorbent-containing active material layer which is a characteristic part of the present invention is formed on both surfaces of the positive electrode current collector 33, an electrolyte layer 35, And a negative electrode plate in which a negative electrode active material layer 37 provided with a gas adsorbent-containing active material layer, which is a characteristic part of the present invention, is formed on both surfaces of the negative electrode current collector 36 (one side for the lowermost layer and the uppermost layer of the power generation element) It has the structure which laminated | stacked. In addition, since it has already demonstrated using FIG. 1 (A)-(C) about the detailed structure (arrangement structure) of the positive electrode active material layer which provided the gas adsorbent containing active material layer, and a negative electrode active material layer, Here, illustration and illustration are omitted. In addition, the positive electrode (terminal) lead 39 and the negative electrode (terminal) lead 40 that are electrically connected to the electrode plates (positive electrode plate and negative electrode plate) are connected to the positive electrode current collector 33 and the negative electrode current collector 36 of each electrode plate. It is attached by sonic welding, resistance welding, or the like, and has a structure that is sandwiched between the heat fusion parts and exposed to the outside of the battery outer packaging material 32.

  FIG. 4 is a schematic cross-sectional view schematically showing the entire structure of a bipolar flat (stacked) lithium ion secondary battery (hereinafter also simply referred to as a bipolar battery). As shown in FIG. 4, in the bipolar battery 41, the electrolyte layer 46 is sandwiched between one or two or more bipolar electrodes 45, and the positive electrode active material 43 and the negative electrode active material layer 44 of the adjacent bipolar electrode 45 Are designed to face each other. Here, the bipolar electrode 45 has a structure in which the positive electrode active material layer 43 is provided on one surface of the current collector 42 and the negative electrode active material layer 44 of the present invention is provided on the other surface. That is, in the bipolar battery 41, a plurality of bipolar electrodes 45 having the positive electrode active material layer 43 on one surface of the current collector 42 and the negative electrode active material layer 44 on the other surface are disposed via the electrolyte layer 46. An electrode laminate (bipolar battery main body) 47 having a laminated structure is provided. Further, the uppermost layer and the lowermost layer electrode 45a, 45b of the electrode laminate 47 may not have a bipolar electrode structure, and the positive electrode active material layer 43 of only one side required for the current collector 42 (or terminal plate) or A structure in which the negative electrode active material layer 44 is disposed may be employed. In the bipolar battery 41, positive and negative electrode leads 48 and 49 are joined to current collectors 42 at both upper and lower ends, respectively.

  Note that the number of stacked bipolar electrodes 45 (including the electrodes 45a and 45b) is adjusted according to a desired voltage. Further, in the bipolar battery 41, the number of lamination of the bipolar electrode 45 may be reduced if a sufficient output can be secured even if the battery is made as thin as possible. Also in the bipolar battery 41, in order to prevent external impact and environmental degradation during use, the electrode laminate 47 portion is sealed under reduced pressure in a battery outer package (outer package) 50, and the electrode leads 48 and 49 are connected to the battery. It is preferable that the structure is taken out of the exterior material 50. The basic configuration of the bipolar battery 41 can be said to be a configuration in which a plurality of stacked single battery layers (single cells) are connected in series. The bipolar lithium ion secondary battery is basically the same as the above-described non-bipolar lithium ion secondary battery except that its electrode structure is different. To do.

[Current collector]
The current collector that can be used in the present invention is not particularly limited, and conventionally known current collectors can be used. For example, aluminum foil, stainless steel (SUS) foil, nickel-aluminum clad material, copper-aluminum clad material, SUS-aluminum clad material, or a plated material of a combination of these metals can be preferably used. Further, a current collector in which a metal surface is coated with aluminum may be used.

  In some cases, a current collector (composite current collector) in which two or more metal foils are bonded together may be used. When the composite current collector is used, as a material for the positive electrode current collector, for example, a conductive metal such as aluminum, an aluminum alloy, SUS, or titanium can be used, and aluminum is particularly preferable. On the other hand, as the material of the negative electrode current collector, for example, conductive metals such as copper, nickel, silver, and SUS can be used, and SUS and nickel are particularly preferable. Further, in the composite current collector, the positive electrode current collector and the negative electrode current collector may be electrically connected to each other directly or via a conductive intermediate layer made of a third material. In addition to the flat plate (foil), the positive electrode current collector and the negative electrode current collector are constituted by a lath plate, that is, a plate in which a mesh space is formed by expanding a plate with a cut. Can also be used.

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

[Positive electrode active material layer (positive electrode)]
In the present invention, a gas adsorbent-containing active material layer is formed on at least one surface of a positive electrode active material layer (hereinafter referred to as a positive electrode active material layer that is not a gas adsorbent-containing layer). However, when the gas adsorbent-containing active material layer is formed on the negative electrode active material layer side, the gas adsorbent-containing layer is not necessarily required.

  Here, the gas adsorbent-containing layer is a layer that contains more carbon material than at least the adjacent electrode active material layer. This is because it is the simplest method for determining whether the product falls within the technical scope of the present invention by decomposing or analyzing the product. That is, a carbon material as described later can be used for the gas adsorbent that can be used in the present invention, but a carbon material may also be used for the conductive additive and the negative electrode active material. The conductive aid and the carbon material of the negative electrode active material added for other purposes of use are added to the entire electrode active material layer in the same manner as in the prior art. Therefore, the definition of the gas adsorbent-containing layer is defined as described above in order to clearly and easily distinguish between the carbon material used in such different usage forms and the gas adsorbent of the present invention. However, in the present invention, it is not necessary to use the above definition if it can be easily distinguished (discriminated) from the carbon material used for the conductive additive and the negative electrode active material without using the above definition. In this case, the gas adsorbent-containing layer referred to in the present invention can be said to be a layer containing a carbon adsorbent and / or a gas adsorbent other than the carbon material such as activated carbon, carbon nanotube, and carbon sheet that can be a gas adsorbent. .

  Therefore, the gas adsorbent-containing active material layer refers to a layer in which an active material is further contained in the gas adsorbent-containing layer defined above.

  In the following, (1) a positive electrode active material layer that is not a gas adsorbent-containing layer (also simply referred to as a positive electrode active material layer) or a form of a gas adsorbent-containing layer (2) a positive electrode active material layer containing a gas adsorbent (Also referred to simply as a gas adsorbent-containing positive electrode active material layer), which is another form of the gas adsorbent-containing layer (3) a layer that does not contain a positive electrode active material and contains a gas adsorbent (simply gas adsorbent alone This will be described in the order of the content layer.

(1) Positive electrode active material layer that is not a gas adsorbent-containing layer (ordinary general positive electrode active material layer)
The positive electrode active material layer that is not the gas adsorbent-containing layer of (1) refers to a layer that contains less carbon material than the gas adsorbent-containing layer, according to the above definition. Further, when not based on the above definition, it refers to a layer that does not contain a carbon adsorbent that can be a gas adsorbent, such as activated carbon, carbon nanotube, and carbon sheet and / or a gas adsorbent other than the carbon material.

  The positive electrode active material layer that is not the gas adsorbent-containing layer (1) contains a positive electrode active material. In addition to this, a conductive assistant for enhancing electron conductivity, an electrolyte supporting salt for enhancing ion conductivity, a binder, a polymer gel or a solid electrolyte (host polymer, electrolytic solution, etc.) and the like can be included. When a polymer gel electrolyte is used for the electrolyte layer, it is sufficient that a conventionally known binder, a conductive auxiliary agent for enhancing electronic conductivity, and the like are contained. Salt etc. may not be included. Even when a solution electrolyte is used for the electrolyte layer, the positive electrode active material layer may not contain a host polymer, an electrolytic solution, a lithium salt, or the like as a raw material of the polymer electrolyte.

The positive electrode active material is not particularly limited, and a conventionally known positive electrode active material can be used. Among these, it is preferable to use a composite oxide of lithium and transition metal (lithium-transition metal oxide). This is because a battery having excellent capacity and output characteristics can be configured. Specifically, as such a lithium-transition metal oxide, Li · Mn based composite oxide such as LiMn ₂ O ₄ , Li · Co based composite oxide such as LiCoO ₂ , Li ₂ Cr ₂ O ₇ , Li ₂ Li / Cr-based composite oxides such as CrO ₄ , Li / Ni-based composite oxides such as LiNiO ₂ , Li / Fe-based composite oxides such as LiFeO ₂ , and some of these transition metals were substituted with other elements (For example, LiNi _x Co _1-x O ₂ (0 <x <1) and the like). However, it is not necessarily limited to these.

  The average particle size of the positive electrode active material is not particularly limited, but is preferably in the range of 0.01 to 20 μm from the viewpoint of reactivity and cycle durability. However, the present invention is not necessarily limited to the above range. Here, the average particle diameter of the positive electrode active material refers to the average particle diameter of the positive electrode active material particles contained in the positive electrode active material. Therefore, the positive electrode active material particles contained in the positive electrode active material material in the state of primary particles have the primary particle size and a plurality of primary particles are collected to form secondary particles. For the positive electrode active material particles, these average values may be calculated as the particle size of the secondary particles.

  The average particle size of the primary particles constituting the secondary particles is desirably in the range of 0.01 to 5 μm, and more desirably in the range of 0.05 to 2 μm. The average particle size of the secondary particles is desirably in the range of 0.05 to 20 μm, and more desirably in the range of 0.1 to 5 μm. However, the present invention is not necessarily limited to the above range.

  The particle diameter of the positive electrode active material particles (including primary particles and secondary particles) can be measured by, for example, SEM observation or TEM observation. The positive electrode active material particles include those having primary particles having different aspect ratios and secondary particles (substantially spherical) composed of the primary particles. Accordingly, the particle size and the like referred to above are expressed by the absolute maximum length because the shape of the particles is not uniform, and a sieve mesh (mesh through size or mesh pass size) may be used when sieving. . This also applies to the particle size of negative electrode active material particles, which will be described later. Here, the absolute maximum length is assumed to take the maximum length L among the distances between any two points on the contour lines of the primary particles or the secondary particles 91, as shown in FIG.

  In the present invention, the shape of the secondary particles of the positive electrode active material is approximately spherical, although the shapes that can be taken vary depending on the type and manufacturing method. However, it is not particularly limited as it may be formed in an indefinite shape close to a sphere, etc., and any shape can be used without any problem, improving battery characteristics such as charge / discharge characteristics. It is desirable to select the optimum shape to be obtained as appropriate.

  Examples of the conductive aid include acetylene black, carbon black, graphite, and vapor grown carbon fiber (VGCF). However, it is not necessarily limited to these.

  As the binder, polyvinylidene fluoride (PVdF), SBR, polyimide, or the like can be used. However, it is not necessarily limited to these.

  The polymer gel electrolyte includes a solid polymer electrolyte having ion conductivity and an electrolyte used in a conventionally known non-aqueous electrolyte lithium ion battery, and further has lithium ion conductivity. A structure in which a similar electrolyte solution is held in a non-polymeric skeleton is also included.

Here, the electrolytic solution (electrolyte supporting salt and plasticizer) contained in the polymer gel electrolyte is not particularly limited, and various conventionally known electrolytic solutions can be appropriately used. For example, inorganic acid anion salts such as LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAsF ₆ , LiTaF ₆ , LiAlCl ₄ , Li ₂ B ₁₀ Cl ₁₀ , LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, Li (C 2 _F 5 _{SO 2)} selected from organic acid anion salts such as 2 _N, wherein at least one lithium salt (electrolyte support salt), propylene carbonate, cyclic carbonates such as ethylene carbonate; dimethyl carbonate Chain carbonates such as methyl ethyl carbonate and diethyl carbonate; ethers such as tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane, 1,2-dibutoxyethane; γ-butyrolactone, etc. Lactones; Nitto such as acetonitrile Lyls; Esters such as methyl propionate; Amides such as dimethylformamide; Plasticizers such as aprotic solvents (organic) mixed with at least one selected from methyl acetate and methyl formate Those using a solvent) can be used. However, it is not necessarily limited to these.

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

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

As an electrolyte support salt to increase the ionic conductivity, for _{example, LiPF 6, LiBF 4, LiClO} 4, LiAsF 6, LiTaF 6, LiAlCl 4, Li 2 B 10 Cl 10 inorganic acid anion salts such as, Li ( An organic acid anion salt such as CF ₃ SO ₂ ) ₂ N, Li (C ₂ F ₅ SO ₂ ) ₂ N (LiBETI), or a mixture thereof can be used. However, it is not necessarily limited to these.

  The ratio (mass ratio) between the host polymer and the electrolytic solution in the polymer gel electrolyte may be determined according to the purpose of use, but is in the range of 2:98 to 90:10.

  The amount of positive electrode active material, conductive additive, binder, polymer electrolyte (host polymer, electrolyte, etc.), and electrolyte support salt (lithium salt) in the positive electrode active material layer depends on the intended use of the battery (emphasis on output, energy Should be determined appropriately in consideration of ion conductivity.

  The film thickness of the positive electrode active material layer of the above (1) is not particularly limited, and should be determined in consideration of the intended use of the battery (emphasis on output, emphasis on energy, etc.) and ion conductivity. Specifically, the thickness of the general positive electrode active material layer (1) is 1 to 500 μm. Within this range, a sufficient capacity can be ensured even when the gas adsorbent-containing active material layer of the present invention is used in combination.

  In addition, from the relationship defined above, the positive electrode active material layer of (1) should have less carbon material than the gas adsorbent-containing layer of (2) or (3), and within the range satisfying this relationship. If present, the gas adsorbent of the present invention may be included as a part of the carbon material contained in the positive electrode active material layer. Alternatively, when the carbon material used as the gas adsorbent of the present invention has a performance as a conductive auxiliary, the gas adsorbent of the present invention may be used for a part or all of the conductive auxiliary. It can be said. By doing so, for example, even when the gas adsorbent-containing active material layer is formed only at the interface with the current collector without reducing the capacity, the gas at the interface with the electrolyte layer is used as the active material of (1). It can be adsorbed by the gas adsorbent in the layer. Further, the gas generated in the active material layer (1) during long-term use of the battery can be adsorbed by the gas adsorbent in the active material layer (1). The gas adsorbent will be described in the gas adsorbent-containing positive electrode active material layer (2) below.

(2) Positive electrode active material layer containing gas adsorbent (gas adsorbent-containing positive electrode active material layer)
The gas adsorbent-containing positive electrode active material layer includes a positive electrode active material and a gas adsorbent. In addition to this, a conductive assistant for enhancing electron conductivity, an electrolyte supporting salt for enhancing ion conductivity, a binder, a polymer gel or a solid electrolyte (host polymer, electrolytic solution, etc.) and the like can be included.

  Each component other than the gas adsorbent is as described in the positive electrode active material layer of (1) above. In the present invention, as described in the first to third embodiments, it is more effective that the gas adsorbent-containing active material layer also includes an electrode active material. It can be said that the gas adsorbent-containing positive electrode active material layer (2) is more preferable than the single-containing layer from the viewpoint of increasing the capacity.

  Here, the gas adsorbent is not particularly limited, but is excellent in reducing the internal resistance of the battery by adsorbing the gas generated during the first charge / discharge and long-term use of the battery, activated carbon, Carbon materials such as carbon nanotubes and carbon sheets can be suitably used. In addition, as a carbon sheet, a conventionally well-known thing can be used, An activated carbon sheet, for example, the woven fabric of activated carbon fiber like Kyonl, etc. can be utilized. A gas adsorbent may be used alone or in combination of two or more. However, the gas adsorbent of the present invention is not limited thereto, and conventionally known, for example, silica gel, activated alumina, zeolite, various clays, iron oxide, magnesium perchlorate, ion exchange resins, various metal salts and the like. Can be mentioned. Among these, a material that affects the charge / discharge reaction of the lithium ion secondary battery or does not affect the electrolyte layer may be appropriately selected and used. When these gas adsorbents are charged and discharged for the first time, the gas generated during long-term use of the battery can be adsorbed to reduce the internal resistance of the battery. In particular, a material that is easily stuck in the electrolyte layer, such as a carbon nanotube, is preferably used on the current collector side. On the other hand, for the electrolyte membrane side, it is desirable to select one that has little influence on the electrolyte layer such as activated carbon or carbon sheet. However, the use of the carbon nanotubes on the electrolyte membrane side is not limited. For example, the carbon nanotubes can be used by controlling the length of the carbon nanotubes.

  The gas adsorbent desirably has a content of 7 wt% or less based on the total amount of the gas adsorbent-containing positive electrode active material layer. This is because a battery excellent in battery capacity and output characteristics can be constructed. Although depending on the type of gas adsorbent, when the amount exceeds 7 wt% with respect to the total amount of the gas adsorbent-containing positive electrode active material layer, the amount of active material in the gas adsorbent-containing positive electrode active material layer decreases, and the battery capacity Since the output is reduced, the gas adsorbent is preferably 7 wt% or less. Also, if the amount of the gas adsorbent is small, gas adsorption cannot be sufficiently performed, so the content of the gas adsorbent is more in the range of 2 to 7 wt% with respect to the total amount of the active material layer containing the gas adsorbent. desirable.

  Since the size of the gas adsorbent varies depending on the form, it is difficult to uniquely define and is not particularly limited, but the gas adsorbent-containing positive electrode active material layer of (2) As long as it does not affect the charge / discharge reaction in the above-mentioned range, it can be selected as appropriate so as to satisfy the thickness range of the gas adsorbent-containing positive electrode active material layer (2) shown below. It is desirable to use it.

  Further, the shape (form) of the gas adsorbent is not particularly limited, and as described above, it is spherical, such as powder, granule, etc .; nanotube, fiber; sheet (including non-woven fabric, etc.) And various other forms.

  The film thickness of the gas adsorbent-containing positive electrode active material layer described in (2) above is not particularly limited, and is determined in consideration of the intended use of the battery (output priority, energy priority, etc.) and ion conductivity. Should. Specifically, if the thickness of the gas adsorbent-containing positive electrode active material layer (2) is in the range of 1 to 15 μm, it can be removed in the battery without causing a decrease in battery capacity. The gas that was not present can be adsorbed, and the internal resistance of the battery can be reduced.

(3) Layer that does not contain a positive electrode active material but contains a gas adsorbent (gas adsorbent-containing positive electrode layer)
The gas adsorbent-containing positive electrode layer contains a gas adsorbent. In addition to this, a conductive assistant for enhancing electron conductivity, an electrolyte supporting salt for enhancing ion conductivity, a binder, a polymer gel or a solid electrolyte (host polymer, electrolytic solution, etc.) and the like can be included.

  These constituent components are as described in the positive electrode active material layer (1) and the gas adsorbent-containing positive electrode active material layer (2).

  Since the gas adsorbent-containing positive electrode layer does not contain a positive electrode active material, it cannot contribute to an increase in capacity. Therefore, it is desirable that the gas adsorbent-containing positive electrode layer be thinned within a range in which the gas adsorption effect can be effectively exhibited and the battery internal resistance can be reduced.

  From this viewpoint, the film thickness of the gas adsorbent-containing positive electrode layer is 1 to 15 μm. Within this range, it is possible to suppress a decrease in battery capacity, adsorb a gas that could not be removed within the battery, and reduce the battery internal resistance. The content of the gas adsorbent is desirably in the range of 2 to 7 wt% with respect to the total amount of the gas adsorbent-containing positive electrode layer. This is because a battery excellent in battery capacity and output characteristics can be constructed.

  Further, the film thickness of the whole positive electrode active material layer formed by appropriately combining the layers (1) to (3) described above is not particularly limited, and the purpose of use of the battery (emphasis on output, importance on energy, etc.), ion It should be determined in consideration of conductivity. The total thickness of a general positive electrode active material layer is 1 to 500 μm. If it is this range, the function by the gas adsorbent containing active material layer of this invention can be expressed effectively.

  Further, the ratio between the thickness of the active material layer (1) and the thickness of the gas adsorbent-containing layer (2) to (3) is not particularly limited. Taking into account the purpose of use of the battery (output priority, energy priority, etc.) and ion conductivity, while suppressing the decrease in battery capacity, gas is adsorbed to reduce the internal resistance of the battery. These ratios should be determined so that a secondary battery can be provided.

[Negative electrode active material layer (negative electrode)]
In the present invention, a gas adsorbent-containing active material layer is formed on at least one surface of the negative electrode active material layer. However, when the gas adsorbent-containing active material layer is formed on the positive electrode active material layer side, the gas adsorbent-containing layer is not necessarily required.

  Here, the gas adsorbent-containing layer is as defined in the above section [Positive electrode active material layer (positive electrode)].

  Therefore, in the following, (1) a negative electrode active material layer that is not a gas adsorbent-containing layer (also simply referred to as a negative electrode active material layer) and a form of a gas adsorbent-containing layer (2) a negative electrode active material containing a gas adsorbent A material layer (also simply referred to as a gas adsorbent-containing negative electrode active material layer), which is another form of the gas adsorbent-containing layer (3) a layer containing no gas active material and containing a gas adsorbent (simply gas adsorption) (Also referred to as an agent-containing negative electrode layer).

(1) Negative electrode active material layer that is not a gas adsorbent-containing layer (ordinary general negative positive electrode active material layer)
The negative electrode active material layer that is not the gas adsorbent-containing layer (1) refers to a layer that contains less carbon material than the gas adsorbent-containing layer, according to the above definition. Further, when not based on the above definition, it refers to a layer that does not contain a carbon adsorbent that can be a gas adsorbent, such as activated carbon, carbon nanotube, and carbon sheet and / or a gas adsorbent other than the carbon material.

  The negative electrode active material layer that is not the gas adsorbent-containing layer (1) contains a negative electrode active material. In addition to this, conductive aids to enhance electronic conductivity, binders, electrolyte supporting salts (lithium salts) to enhance ionic conductivity, polymer gels or solid electrolytes (host polymers, electrolytes, etc.), etc. Can be. Except for the type of the negative electrode active material, the contents are basically the same as those described in the section of [Positive electrode active material layer (positive electrode)] of the present invention, and thus the description thereof is omitted here.

  The negative electrode active material is not particularly limited, and a negative electrode active material that is also used in a conventionally known solution-type lithium ion battery can be used. Among these, it is preferable to use a carbon material or a composite oxide of lithium and a transition metal (lithium-transition metal oxide). This is because a battery having excellent capacity and output characteristics can be configured. Specifically, the carbon material suitable as the negative electrode active material is selected from carbon materials such as natural graphite, artificial graphite, amorphous carbon, coke and mesophase pitch carbon fiber, graphite, and hard carbon which is amorphous carbon. It is desirable to use a negative electrode active material mainly composed of at least one kind. However, it is not necessarily limited to these. Specific examples of the lithium-transition metal oxide include composite oxides of titanium and lithium (lithium-titanium composite oxide). However, it is not necessarily limited to these.

  The average particle diameter of the negative electrode active material is not particularly limited, but is preferably in the range of 0.01 to 20 μm from the viewpoint of reactivity and cycle durability. The particle diameter of the negative electrode active material particles (including primary particles and secondary particles) can be measured by, for example, SEM observation or TEM observation.

  Although the shape of the positive electrode active material particles varies depending on the type, manufacturing method, and the like, the shape is generally spherical. However, it is not particularly limited as it may be formed in an indefinite shape close to a sphere, etc., and any shape can be used without any problem, improving battery characteristics such as charge / discharge characteristics. It is desirable to select the optimum shape to be obtained as appropriate.

(2) Negative electrode active material layer containing a gas adsorbent (gas adsorbent-containing negative electrode active material layer)
The gas adsorbent-containing negative electrode active material layer includes a negative electrode active material and a gas adsorbent. In addition to this, a conductive assistant for enhancing electron conductivity, an electrolyte supporting salt for enhancing ion conductivity, a binder, a polymer gel or a solid electrolyte (host polymer, electrolytic solution, etc.) and the like can be included.

  The gas adsorbent-containing negative electrode active material layer is basically the same as the content described in “(2) Gas adsorbent-containing positive electrode active material layer” in the section of “Positive electrode active material layer (positive electrode)” of the present invention. Therefore, the description is omitted here.

(3) Layer that does not contain negative electrode active material and contains gas adsorbent (gas adsorbent-containing negative electrode layer)
The gas adsorbent-containing negative electrode layer contains a gas adsorbent. In addition to this, a conductive assistant for enhancing electron conductivity, an electrolyte supporting salt for enhancing ion conductivity, a binder, a polymer gel or a solid electrolyte (host polymer, electrolytic solution, etc.) and the like can be included.

  The gas adsorbent-containing negative electrode layer is basically the same as the content described in “(3) Gas adsorbent-containing positive electrode layer” in the section of [Positive electrode active material layer (positive electrode)] of the present invention. Then, explanation is omitted.

  Furthermore, the film thickness of the whole negative electrode active material layer formed by appropriately combining the above-mentioned layers (1) to (3) is the same as the content described in the section of [Positive electrode active material layer (positive electrode)] of the present invention. Therefore, the description is omitted here.

[Electrolyte layer]
In the present invention, depending on the purpose of use, (a) an electrolyte layer comprising a separator containing an electrolytic solution (solution electrolyte), (b) an electrolyte layer using a polymer gel electrolyte, and (c) a polymer solid electrolyte are used. It can be applied to any electrolyte layer. Preferably, (b) an electrolyte layer using a polymer gel electrolyte and / or (c) an electrolyte layer using a polymer solid electrolyte is further used. This is because, in the conventional method, the gas generated in a bipolar lithium ion secondary battery using a polymer electrolyte or a gel electrolyte as the electrolyte layer is difficult to move. Electrode active material layer / electrolyte layer, electrode active material layer / It was trapped at the current collector interface. By arranging the layer containing the gas adsorbent of the present invention, the gas adsorbent in the layer containing the gas adsorbent effectively adsorbs the gas generated during the initial charge and long-term use. Because it can. That is, in the case of polymer electrolytes and gel electrolytes, the gas generated during the initial charge / discharge or the gas generated during long-term use of the battery is trapped at the electrode active material layer / electrolyte interface, electrode active material layer / current collector foil interface, and conventional battery sealing Since the process cannot be completely removed, the present invention is effective for a lithium ion secondary battery using a polymer electrolyte and a gel electrolyte. As a result, the gas that could not be removed in the battery can be adsorbed, and the battery internal resistance can be reduced.

(A) Electrolyte layer comprising a separator containing an electrolytic solution (solution electrolyte) The electrolytic solution that can be contained in the separator is included in the polymer gel electrolyte described in the above section [Positive electrode active material layer (positive electrode)]. it is possible to use the same as the electrolytic solution (electrolyte salt and plasticizer) described here is omitted, as a preferable example of the electrolytic solution, as an _electrolyte, LiClO _4, LiAsF 6, LiPF ₅ , LiBOB, LiCF ₃ SO ₃ and Li (CF ₃ SO ₂ ) ₂ are used, and as a solvent (plasticizer), ethylene carbonate (EC), propylene carbonate, diethyl carbonate (DEC), dimethyl carbonate, methyl Ethyl carbonate, 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran The concentration of the electrolyte is adjusted to 0.5 to 2 mol / liter by dissolving at least one of ethers composed of 1,3-dioxolane and γ-butyllactone and dissolving the electrolyte in the solvent. However, the present invention should not be limited to these.

  The separator is not particularly limited, and a conventionally known separator can be used. For example, a porous separator (for example, a polyolefin-based microporous separator) made of a polymer that absorbs and holds the electrolytic solution, a nonwoven fabric separator, or the like can be used. The polyolefin microporous separator having the property of being chemically stable to an organic solvent has an excellent effect that the reactivity with the electrolyte (electrolytic solution) can be kept low.

  Examples of the material of the porous separator include polyethylene (PE), polypropylene (PP), a laminate having a three-layer structure of PP / PE / PP, and polyimide.

  As the material of the nonwoven fabric separator, for example, conventionally known materials such as cotton, rayon, acetate, nylon, polyester, polypropylene, polyethylene and other polyolefins, polyimide, and aramid can be used. Depending on mechanical strength, etc., they are used alone or in combination.

  Further, 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. That is, if the bulk density of the nonwoven fabric is too large, the proportion of the non-electrolyte material in the electrolyte layer becomes too large, which may impair the ionic conductivity in the electrolyte layer.

  The thickness of the separator (including the nonwoven fabric separator) cannot be unambiguously defined because it varies depending on the application, but in applications such as motor drive power supplies such as hybrid cars, electric cars, and fuel cell cars, 5 It is desirable that it is -200 micrometers. When the thickness of the separator is within such a range, it is possible to suppress increase in retention and resistance. In addition, there is an effect of securing mechanical strength in the thickness direction and ensuring high output performance because it is desirable to prevent a short circuit caused by fine particles entering the separator and to narrow the space between the electrodes for high output. . In addition, when a plurality of batteries are connected, the electrode area increases, so that it is desirable to use a thick separator in the above range in order to increase the reliability of the battery.

  It is desirable that the fine pore diameter of the porous separator is 1 μm or less (usually a pore diameter of about several tens of nm). When the average diameter of the fine pores in the separator is within the above range, the "shutdown phenomenon" that the separator melts and closes the fine pores, such as during abnormal heat generation, quickly occurs, and the reliability in abnormal situations increases, resulting in heat resistance. Has the effect of improving. Here, the average diameter of the micropores of the separator is calculated as an average diameter obtained by observing the separator with a scanning electron microscope or the like and statistically processing the photograph with an image analyzer or the like.

  The porosity of the porous separator is desirably 20 to 50%. The separator's porosity is within the above range, preventing output from being reduced due to the resistance of the electrolyte (electrolyte), and preventing the short circuit caused by fine particles penetrating the separator's pores (micropores). It has the effect of securing both sexes. Here, the porosity of the separator is a value obtained as a volume ratio from the density of the raw material resin and the density of the separator of the final product.

  Moreover, it is preferable that the porosity of the said nonwoven fabric separator is 50 to 90%. If the porosity is less than 50%, the electrolyte retention deteriorates, and if it exceeds 90%, the strength is insufficient.

  The amount of the electrolytic solution impregnated in the separator may be impregnated to the range of the liquid retention capacity of the separator, but may be impregnated beyond the liquid retention capacity range. This can prevent impregnation of the electrolyte from the electrolyte layer by injecting a resin into the electrolyte seal portion, and therefore can be impregnated as long as the electrolyte layer can be retained. The electrolyte can be impregnated in the separator by a conventionally known method, for example, the electrolyte can be completely sealed after being injected by a vacuum injection method or the like. The electrolyte solution is housed in a battery outer packaging material, melt-sealed except for a part of the outer periphery of the battery outer packaging material, and then injected by a vacuum injection method or the like. The separator can be impregnated with the electrolytic solution by a conventionally known method such as complete sealing.

(B) Electrolyte layer using polymer gel electrolyte or (c) polymer solid electrolyte First, (b) an electrolyte layer using a polymer gel electrolyte includes an electrolyte layer composed only of a polymer gel electrolyte. An electrolyte layer made of a separator containing a polymer gel electrolyte is included. Similarly, (c) the electrolyte layer using the polymer solid electrolyte includes an electrolyte layer made of a separator including the polymer solid electrolyte in addition to the electrolyte layer composed of only the polymer solid electrolyte.

  As the polymer gel electrolyte and the polymer solid electrolyte, the same polymer gel electrolyte and polymer solid electrolyte as described in the section of [Positive electrode active material layer (positive electrode)] described above can be used. Description is omitted. In addition, as the separator, since the separator similar to the separator described in “(a) Separator containing electrolytic solution (solution electrolyte)” in the section of [Electrolyte layer] already described can be used, the description here is Omitted.

  Further, the content of the polymer gel electrolyte or the polymer solid electrolyte in the separator may be contained up to the range of the gel or solid polymer retention capacity in the separator, but the content of the polymer gel electrolyte or solid polymer electrolyte exceeds the retention capacity range. May be. Even if it is a lithium ion secondary battery (bipolar battery) using a bipolar electrode in which a short circuit (liquid junction) between electrodes is a problem, by forming the insulating seal layer shown below, Therefore, the electrolyte layer can be contained (impregnated) as long as it can be retained (retained) in the electrolyte layer. The polymer gel electrolyte or polymer solid electrolyte is prepared by applying and impregnating a precursor solution containing these electrolytes to the separator, followed by cross-linking polymerization with heat or ultraviolet rays. A polymer solid electrolyte can be contained and held (see “Formation of gel electrolyte layer” in Procedure 2 of Examples described later).

  The electrolyte layers (a) to (c) may be used in one battery.

  The polymer electrolyte (polymer gel electrolyte or polymer solid electrolyte) can be included in the electrolyte layer, the positive electrode active material layer, and the negative electrode active material layer, but the same polymer electrolyte may be used depending on the layer. Different polymer electrolytes may be used.

  By the way, a host polymer for a polymer gel electrolyte that is preferably used at present is a polyether polymer such as PEO and PPO. For this reason, the oxidation resistance on the positive electrode side under high temperature conditions is weak. Therefore, when a positive electrode active material having a high redox potential is used, the capacity of the negative electrode active material layer is preferably smaller than the capacity of the positive electrode active material layer facing through the polymer gel electrolyte layer. When the capacity of the negative electrode active material layer is smaller than the capacity of the positive electrode active material layer facing, it is possible to prevent the positive electrode potential from being excessively increased at the end of charging. In addition, the capacity | capacitance of a positive electrode active material layer and a negative electrode active material layer can be calculated | required from manufacturing conditions as theoretical capacity | capacitance at the time of manufacturing a positive electrode active material layer and a negative electrode active material layer. You may measure the capacity | capacitance of a finished product directly with a measuring device. However, if the capacity of the negative electrode active material layer is smaller than the capacity of the opposing positive electrode active material layer, the negative electrode potential may be lowered too much and the durability of the battery may be impaired, so it is necessary to pay attention to the charge / discharge voltage. For example, care should be taken not to lower the durability by setting the average charge voltage of one cell (single cell layer) to an appropriate value for the oxidation-reduction potential of the positive electrode active material.

  The thickness of the electrolyte layer constituting the battery is not particularly limited. However, in order to obtain a compact battery, it is preferable to make it as thin as possible within a range in which the function as an electrolyte can be ensured, and the thickness of the electrolyte layer is preferably in the range of 5 to 200 μm.

[Insulating seal layer]
The insulating seal layer is mainly used in the case of a lithium ion secondary battery using a bipolar electrode. This insulating seal layer is formed around each electrode for the purpose of preventing short-circuits caused by contact between adjacent current collectors in the battery or slight unevenness at the end of the laminated electrode. Is. In the present invention, if necessary, an insulating seal layer may be provided around the electrode (refer to Procedure 3 in Examples described later). When this is used as a vehicle driving or auxiliary power source, it is necessary to completely prevent a short circuit (liquid junction) due to the electrolytic solution (including the electrolytic solution component in the polymer gel electrolyte). Furthermore, vibrations and impacts on the battery are loaded for a long time. Therefore, from the viewpoint of prolonging battery life, it is desirable to install an insulating seal layer in order to ensure longer-term reliability and safety, and in terms of providing a high-quality, large-capacity power supply. is there.

  The insulating seal layer may have any insulating property, sealing property against falling off of the solid electrolyte, sealing property against moisture permeation from the outside (sealing property), heat resistance under battery operating temperature, etc. For example, epoxy resin, rubber, polyethylene, polypropylene, polyimide and the like can be used, but epoxy resin is preferable from the viewpoint of corrosion resistance, chemical resistance, ease of production (film forming property), economy, and the like.

[Positive electrode and negative electrode terminal plate]
The positive electrode and the negative electrode terminal plate may be used as necessary. For example, in the case of a bipolar lithium ion secondary battery, depending on the laminated (or wound) structure, the electrode terminal may be directly taken out from the outermost current collector. In this case, the positive electrode and negative electrode terminal plates are used. It is not necessary (see FIG. 4).

  When using positive and negative terminal plates, in addition to having a function as a terminal, it is better to be as thin as possible from the viewpoint of thinning, but the laminated electrode, electrolyte and current collector all have mechanical strength. Since it is weak, it is desirable to have strength to sandwich and support these from both sides. Furthermore, it can be said that the thickness of the positive electrode and the negative electrode terminal plate is usually preferably about 0.1 to 2 mm from the viewpoint of suppressing the internal resistance at the terminal portion.

  As materials for the positive electrode and the negative electrode terminal plate, materials used in a conventionally known lithium ion battery can be used. For example, aluminum, copper, titanium, nickel, stainless steel (SUS), and alloys thereof can be used. Aluminum is preferably used from the viewpoints of corrosion resistance, ease of production, economy, and the like.

  The material of the positive electrode terminal plate and the negative electrode terminal plate may be the same material or different materials. Furthermore, the positive electrode and the negative electrode terminal plate may be a laminate of different materials.

[Positive electrode and negative electrode lead]
Regarding the positive electrode and the negative electrode lead, not only the bipolar type but also the same type as that used in a conventionally known lithium ion secondary battery that is not a bipolar type can be used. In addition, the part taken out from the battery exterior material (battery case) does not affect the product (for example, automobile parts, especially electronic devices, etc.) by contacting with peripheral devices or wiring and leaking electricity. It is preferable to coat with a heat-resistant insulating heat-shrinkable tube or the like.

[Battery exterior material (battery case)]
Lithium ion secondary batteries are not limited to bipolar types, but in order to prevent external impacts and environmental degradation during use, the entire battery stack or battery winding body, which is the battery body, is used as a battery exterior material or battery case. It is desirable to accommodate in From the viewpoint of weight reduction, a polymer-metal composite laminate in which both surfaces of metals (including alloys) such as aluminum, stainless steel, nickel, and copper are covered with an insulator such as a polypropylene film (preferably a heat-resistant insulator). It is preferable to use a conventionally known battery exterior material such as a film, and a part or all of the peripheral part thereof is bonded by heat fusion so that the battery stack is housed and sealed. In this case, the positive electrode and the negative electrode lead may be structured to be sandwiched between the heat-sealed portions and exposed to the outside of the battery exterior material. In addition, it is preferable to use a polymer-metal composite laminate film having excellent thermal conductivity because heat can be efficiently transmitted from a heat source of an automobile and the inside of the battery can be quickly heated to the battery operating temperature. The polymer-metal composite laminate film is not particularly limited, and a conventionally known film in which a metal film is disposed between polymer films and the whole is laminated and integrated can be used. As specific examples, for example, an outer protective layer made of a polymer film (laminate outermost layer), a metal film layer, a heat-sealing layer made of a polymer film (laminate innermost layer), and the whole is laminated and integrated. The thing which becomes. Specifically, in the polymer-metal composite laminate film used for the exterior material, a heat-resistant insulating resin film is first formed as a polymer film on both surfaces of the metal film, and heat fusion is performed on at least one heat-resistant insulating resin film. An insulating insulating film is laminated. Such a laminate film is heat-sealed by an appropriate method, whereby the heat-welding insulating film portion is fused and joined to form a heat-sealing portion. An example of the metal film is an aluminum film. Moreover, as said insulating resin film, a polyethylene tetraphthalate film (heat-resistant insulating film), a nylon film (heat-resistant insulating film), a polyethylene film (heat-bonding insulating film), a polypropylene film (heat-bonding insulating film) ) Etc. can be illustrated. However, the exterior material of the present invention should not be limited to these. In such a laminate film, it is possible to easily and surely join one to one (bag-like) laminate films by heat fusion using a heat fusion insulating film by ultrasonic welding or the like. In order to maximize the long-term reliability of the battery, metal films that are constituent elements of the laminate sheet may be directly joined. Ultrasonic welding can be used to join the metal films by removing or destroying the heat-fusible resin between the metal films.

  Next, the manufacturing method of the lithium ion secondary battery of this invention is demonstrated. Specifically, first, a bipolar lithium ion secondary battery using a separator including a polymer gel electrolyte in an electrolyte layer, which is one of the preferred embodiments of the method for producing a lithium ion secondary battery of the present invention. A manufacturing method will be described as an example. Further, as described in FIG. 1C, as the bipolar (bipolar) electrode, gas adsorption is performed on the active material layer / electrolyte interface and the active material / current collector interface in both the positive electrode active material layer and the negative electrode active material layer. Although an example using an electrode having a structure provided with an active material layer containing an agent will be described, the method for producing a lithium ion secondary battery of the present invention should not be limited to the following method.

[Outline of the production method]
First, a positive electrode active material layer in which a gas adsorbent-containing positive electrode active material layer is provided on one surface of a current collector is prepared, and a gas adsorbent-containing negative electrode is formed on the surface on which the positive electrode active material layer of the current collector is formed and the other surface. By producing a negative electrode active material layer provided with an active material layer, a single battery (cell) is obtained. Next, a plurality of the produced single cells (cells) are laminated through an electrolyte layer made of a separator containing a polymer gel electrolyte to form an electrode laminate. At this time, an electrode in which only the positive electrode active material layer in which the gas adsorbent-containing positive electrode active material layer is provided on the outermost layer current collector is disposed on the outermost layer on the positive electrode side is disposed, and the outermost layer is disposed on the outermost layer on the negative electrode side. An electrode on which only a negative electrode active material layer in which a gas adsorbent-containing negative electrode active material layer is provided on a current collector is disposed. Thereafter, a tab is taken out from each outermost layer current collector and accommodated in a battery case or the like to produce a bipolar battery. Hereinafter, each step will be described.

[Outline of fabrication of bipolar electrode]
In the step of producing a positive electrode active material layer on one side of the current collector, various positive electrode compositions suitable for a positive electrode active material layer that is not a gas adsorbent-containing layer and a gas adsorbent-containing positive electrode active material layer are prepared. Next, the prepared various positive electrode compositions are applied in an appropriate order on one surface of the current collector, and dried and polymerized to prepare a positive electrode active material layer. Subsequently, in the step of preparing a negative electrode active material layer on the other surface of the current collector, various negative electrode compositions suitable for a negative electrode active material layer that is not a gas adsorbent-containing layer and a gas adsorbent-containing negative electrode active material layer To prepare. Next, on the other surface of the current collector, the prepared various negative electrode compositions are applied in an appropriate order, dried and polymerized to produce a negative electrode active material layer, thereby producing a bipolar electrode.

(1) Preparation of composition for positive electrode The composition for positive electrode is normally obtained as a slurry (slurry for positive electrodes), and is sequentially applied to one surface of the current collector.

  Among the positive electrode slurries, the positive electrode active material layer composition (positive electrode active material layer slurry) is a solution containing a positive electrode active material. As other components, a conductive aid, a binder, a polymerization initiator, a host polymer that is a raw material for the polymer gel electrolyte, a lithium salt, and the like are optionally included. For example, the slurry for the positive electrode active material layer is obtained by adding a binder, a conductive additive, a polymerization initiator, a host polymer that is a raw material for the polymer gel electrolyte, a lithium salt, and the like into a solvent containing the positive electrode active material, It is obtained by stirring with.

  Similarly, the gas adsorbent-containing layer composition (gas adsorbent-containing layer slurry) is a solution containing a gas adsorbent. As other components, a positive electrode active material, a conductive additive, a binder, a polymerization initiator, a host polymer that is a raw material for the polymer gel electrolyte, a lithium salt, and the like are optionally included. For example, in a slurry for a gas adsorbent-containing positive electrode active material layer, a gas adsorbent, a binder, a conductive additive, a polymerization initiator, a host polymer that is a raw material for a polymer gel electrolyte, and a lithium salt in a solvent containing the positive electrode active material Etc. are added and stirred with a homomixer or the like. In addition, in the gas adsorbent-containing positive electrode layer slurry, a gas adsorbent, a binder, a conductive additive, a polymerization initiator, a host polymer that is a raw material for the polymer gel electrolyte, a lithium salt, and the like are added to the solvent (dispersion medium). And obtained by stirring with a homomixer or the like.

  Or you may divide the slurry for positive electrode active material layers into two like the Example mentioned later. For example, a slurry for a positive electrode active material layer containing a positive electrode active material, a conductive additive, a binder, etc., and a slurry for a polymer electrolyte containing a polymerization initiator, a host polymer or a lithium salt as a raw material for a polymer gel electrolyte (polymer) It may be divided into an electrolyte precursor solution or a pregel solution.

  Similarly, the gas adsorbent-containing layer slurry may be divided into two. For example, a gas adsorbent-containing layer slurry containing a gas adsorbent, a conductive additive, a binder, (a gas adsorbent-containing positive electrode active material layer slurry is further a positive electrode active material), a polymerization initiator, a polymer gel electrolyte You may divide into the polymer electrolyte slurry containing the host polymer, lithium salt, etc. which are raw materials.

  Such a slurry for polymer electrolyte is formed by applying and impregnating the electrode active material layer on the electrode active material layer after forming the electrode active material layer using the slurry for the positive electrode active material layer and the slurry for the negative electrode active material layer made of other components. You may hold | maintain in the said active material layer by carrying out the crosslinking polymerization by ultraviolet irradiation etc. By doing so, it is excellent in that the polymer electrolyte can be held (supported) at once in each layer constituting the electrode active material layer. That is, in the slurry for polymer electrolyte, it is necessary to carry out cross-linking polymerization by heat or ultraviolet irradiation, etc., and the number of man-hours is significantly larger than when the cross-linking polymerization process is performed individually when forming the three layers constituting the electrode active material layer. Can be reduced. Therefore, in the following, an example in which the slurry for the positive electrode active material layer and the slurry for the gas adsorbent-containing layer and the slurry for the polymer electrolyte are separately manufactured is shown, but the present invention is not limited to these. .

  The positive electrode active material, gas adsorbent, conductive additive, binder, lithium salt, polymer raw material (host polymer) of the polymer gel electrolyte, etc. are basically the constituent requirements of the lithium ion secondary battery of the present invention. Since it is the same as the content described in the section of the positive electrode active material layer, the description here is omitted.

  Examples of the solvent used as necessary when preparing the positive electrode slurry include solvents for adjusting the slurry viscosity such as N-methyl-2-pyrrolidone (NMP) and n-pyrrolidone. Depending on the situation, it is selected as appropriate.

  What is necessary is just to determine suitably the addition amount of a positive electrode active material, lithium salt, and a conductive support agent so that the obtained lithium ion secondary battery may satisfy | fill a predetermined relationship.

  The polymerization initiator needs to be appropriately selected depending on 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 (BDK) is exemplified as the ultraviolet polymerization initiator, and azobisisobutyronitrile (ABIN) is exemplified as the thermal polymerization initiator, but it should not be limited thereto. 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 (polymer raw material of polymer gel electrolyte).

(2) Production of Positive Electrode Active Material Layer After applying the prepared various positive electrode slurries on the current collector, the solvent contained by drying is removed.

  Specifically, taking the case where the positive electrode active material layer 13 of the third form shown in FIG. 1C is formed as an example, first, the gas adsorbent-containing layer slurry is collected by a self-propelled die coater or the like. After coating on one side of 12, the solvent contained by drying is removed. Furthermore, you may press as needed so that it may become a desired film thickness.

  Next, the positive electrode active material layer slurry is applied from above the active material layer 13b with a self-propelled die coater or the like, and then dried to remove the contained solvent. Furthermore, you may press as needed so that it may become a desired film thickness.

  Furthermore, after apply | coating the slurry for gas adsorbent containing layers again on the active material layer 13a with a self-propelled die coater etc., the solvent contained by drying is removed. Furthermore, you may press as needed so that it may become a desired film thickness.

  The thus obtained positive electrode active material layer (in the state not impregnated with the polymer gel electrolyte) 12 includes an active material layer 13b containing a gas adsorbent on the current collector 12, and a gas adsorbent thereon. It has a three-layer structure in which an active material layer 13a that is not present and an active material layer 13b that further includes a gas adsorbent are laminated in this order.

  The method of applying the various positive electrode slurries described above on the current collector or the active material layer may be performed by a known method such as a coater or a screen printing method, preferably by a self-propelled die coater or an ink jet type. It is application | coating by etc.

  In order to dry the applied various positive electrode slurries, a conventionally known device such as a vacuum dryer can be used. The drying conditions may be determined according to the applied positive electrode slurry.

  Each of the produced layers 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.

  Next, in order to produce the negative electrode active material layer on the surface opposite to the surface on which the positive electrode active material layer of the current collector was produced, various negative electrode compositions were prepared in the same manner as the positive electrode active material layer. After that, the negative electrode active material layer is prepared by coating on a current collector and drying.

(3) Preparation of composition for negative electrode The composition for negative electrodes is normally obtained as a slurry (slurry for negative electrodes), and is apply | coated on a collector (a negative electrode collector is included).

  With regard to various negative electrode slurries, except for the positive electrode used as the negative electrode in the various positive electrode slurries, in addition to the raw materials used and the amount added, various slurry preparation methods and polymer electrolyte slurries are combined with other components. The description of the dividing method and the like is also the same as the description in “(1) Preparation of positive electrode composition”, and thus the description thereof is omitted here.

(4) Preparation of negative electrode active material layer After apply | coating the prepared various slurry for negative electrodes to a collector, the solvent contained by drying is removed.

  Regarding the specific coating method and drying conditions shown in the example of the third embodiment shown in FIG. 1 (C), the description in “(2) Preparation of positive electrode active material layer” except that the positive electrode is a negative electrode Since it is basically the same, the description here is omitted.

  The press operation described in the section “(2) Preparation of positive electrode active material layer” is performed, for example, by forming the positive electrode active material layer on one side of the current collector and then performing the entire positive electrode active material layer together. Also good. The same applies to the negative electrode active material. 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. Further, regarding the pressing conditions, even if each layer of the positive electrode active material layer or the negative electrode active material layer or the case where the positive electrode active material layer and / or the entire negative electrode active material layer are collectively performed, the above “(2) It can be prepared within the range described in the section “Preparation of Positive Electrode Active Material Layer”.

(5) Production of electrode laminate (bipolar battery main body) A single battery (cell) produced as described above was cut into a desired size, and a plurality of laminates were produced via separators, and then a gel material was prepared. A bipolar battery is produced by impregnating and polymerizing the solution (pregel solution).

  Examples of the separator include those commonly used such as the above-described microporous polyethylene film, microporous polypropylene film, microporous ethylene-propylene-copolymer film, and nonwoven fabric separator. The number of stacked single cells (cells) is determined in consideration of battery characteristics required for bipolar batteries.

  In the electrode laminate, an electrode in which only the positive electrode layer is formed on the outermost current collector is disposed in the outermost layer on the positive electrode side. In the outermost layer on the negative electrode side, an electrode in which only the negative electrode layer is formed on the outermost current collector is disposed. Further, the outermost current collectors used on the positive electrode side and the negative electrode side may be thicker than the current collector on the intermediate layer.

  The gel raw material solution impregnated in the electrode laminate 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. The host polymer, lithium salt, and the like are the same as those described in the positive electrode active material layer of the bipolar battery, and thus 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 is carried out by laminating a plurality of single cells (cells) via a separator and then immersing the produced electrode laminate in the gel solution or injecting the gel raw material solution. Since the gel raw material solution is not yet gelled, 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 host polymer contained in the laminate impregnated with the gel raw material solution is polymerized (crosslinked) by heat, ultraviolet rays, radiation, electron beams, or the like. Since the polymerization can be carried out simply and reliably, it is correct to carry out the thermal 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. The width of the obtained electrolyte layer is often slightly smaller than the size of the electrode forming portion of the current collector of the single battery (cell), but is not particularly limited.

  In addition, when producing an electrode laminated body, it is preferable to carry out in inert atmosphere, such as argon and nitrogen, from a viewpoint of preventing a water | moisture content etc. mixing into the inside of a battery.

  In the present invention, the electrolyte layer is preferably polymerized (crosslinked) by impregnating a separator with a gel raw material solution or a 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.

(6) Formation of insulating seal layer For example, the insulating seal layer is, for example, first immersed in or impregnated with an epoxy resin with a predetermined width around the unit cell (cell) of the electrode laminate, It is formed by curing an epoxy resin. The current collector is preferably masked with a releasable masking material or the like in advance, and the masking material may be peeled off after the epoxy resin is cured.

  Alternatively, as in the examples described later, the epoxy resin or the like is disposed as a sealing material (insulating sealing layer) on the periphery of at least one electrode active material layer of the bipolar electrode, and heat and pressure are applied to the current collector. The sealing material may be fused. In this case, after further impregnating and holding the gel electrolyte in the electrode active material layer, a plurality of bipolar electrodes impregnated and held with the gel electrolyte and a plurality of gel polymer electrolyte layers are alternately laminated, and heat and pressure are applied, The electrode laminate (bipolar battery body) may be formed by fusing the sealing material with the peripheral portion of the other electrode active material layer of the opposing current collector. Thus, the formation of the insulating seal layer does not necessarily have to be performed after the electrode laminate (bipolar battery main body) is produced, and the most efficient work can be performed as long as the desired insulating seal effect can be exhibited. The insulating seal layer may be formed when good.

(7) Connection of tabs The positive electrode tab and the negative electrode tab are joined and connected to both outermost layers of the electrode laminate. As a method for joining the positive electrode tab and the negative electrode tab, ultrasonic welding or the like having a low joining temperature can be suitably used. However, the method is not limited to this, and a conventionally known method is appropriately used. be able to.

(8) Packing (Battery completion)
Finally, in order to prevent external impact and environmental degradation, the entire electrode laminate is sealed with a battery outer package or battery case to complete a bipolar battery. When sealing, a part of the positive electrode tab and the negative electrode tab are taken out of the battery. The material of the battery exterior material (battery case) is preferably a metal (aluminum, stainless steel, nickel, copper, etc.) whose inner surface is covered with an insulator such as a polypropylene film.

  Next, as a use of the lithium ion secondary battery of the present invention, it can be suitably used for a large-capacity power source that requires high energy density and high output density. For example, it can be suitably used as a power source for driving a vehicle or an auxiliary power source of a hybrid vehicle, an electric vehicle, a hybrid electric vehicle, a fuel cell vehicle, a hybrid fuel cell vehicle, etc. of a gasoline engine or a diesel engine and the secondary battery of the present invention. it can. In this case, it is desirable that the assembled battery is constructed by connecting a plurality of lithium ion secondary batteries of the present invention.

  That is, in the present invention, a plurality of the lithium ion secondary batteries are used as an assembled battery (vehicle submodule) using at least one of a parallel connection, a series connection, a parallel-series connection, or a series-parallel connection. it can. This makes it possible to meet the demands for capacity and voltage for various types of vehicles by combining basic batteries. As a result, it becomes possible to facilitate the design selectivity of required energy and output. For this reason, it is not necessary to design and produce different batteries for various vehicles, and it becomes possible to mass-produce basic batteries and to reduce costs by mass production. Hereinafter, a representative embodiment of the assembled battery (vehicle submodule) will be briefly described with reference to the drawings.

  FIG. 5 shows a schematic diagram of an assembled battery (42V1Ah) in which the bipolar battery (24V, 50 mAh) of the present invention is connected in two lines and 20 lines. The tabs in the parallel part were connected by copper bus bars 56 and 58, and the serial part was connected by vibration welding the tabs 48 and 49 together. The ends of the series part are connected to the terminals 62 and 64 to constitute positive and negative terminals. On both sides of the battery, detection tabs 60 for detecting the voltage of each layer of the bipolar battery 41 are taken out, and their detection lines 53 are taken out to the front part of the assembled battery 51. Specifically, in order to form the assembled battery 51 shown in FIG. 5, five bipolar batteries 41 are connected in parallel by a bus bar 56, and two bipolar batteries 41 connected in parallel are connected to each other by electrode tabs in series. These are stacked in four layers and connected in parallel by a bus bar 58 and housed in a metal assembled battery case 55. In this way, by connecting an arbitrary number of bipolar batteries 41 in series and parallel, an assembled battery 51 that can handle a desired current, voltage, and capacity can be provided. In the assembled battery 51, a positive electrode terminal 62 and a negative electrode terminal 64 are formed at the front side of the metal assembled battery case 55. After connecting the batteries in series and parallel, for example, each bus bar 56 and each positive electrode terminal 62. The negative terminal 64 is connected to the terminal lead 59. Further, the assembled battery 51 has a detection tab terminal 54 for monitoring a battery voltage (a voltage across each single cell layer and further a bipolar battery), and a positive electrode terminal 62 and a negative electrode terminal of an assembled battery case 55 made of metal. 64 is installed at the front of the side surface. All the voltage detection tabs 60 of each bipolar battery 41 are connected to the detection tab terminal 54 via the detection line 53. In addition, an external elastic body 52 is attached to the bottom of the assembled battery case 55, and when a plurality of assembled batteries 51 are stacked to form a composite assembled battery, the distance between the assembled batteries 51 is maintained to prevent vibration. , Impact resistance, insulation, heat dissipation, etc. can be improved.

  In addition to the detection tab terminal 54, the assembled battery 51 may be provided with various measuring devices and control devices depending on the usage. Furthermore, in order to connect the electrode tabs (48, 49) of the bipolar battery 1 or the detection tab 60 and the detection line 53, ultrasonic welding, heat welding, laser welding, electron beam welding, or a rivet is used. You may make it connect using the bus-bars 56 and 58, or using the crimping method. Furthermore, in order to connect the bus bars 56, 58 and the terminal leads 59, etc., ultrasonic welding, heat welding, laser welding, or electron beam welding may be used.

  The external elastic body 52 may be made of the same material as that of the resin group used in the battery of the present invention, but is not limited thereto.

  In the assembled battery of the present invention, the bipolar lithium ion battery of the present invention (simply referred to simply as a bipolar battery), the bipolar battery and the positive and negative electrode materials are the same, and the number of constituent units of the bipolar battery is connected in series. Thus, the lithium ion secondary battery of the present invention having the same voltage (the existing non-bipolar lithium ion secondary battery is also simply referred to as a general battery) may be connected in parallel. That is, the battery forming the assembled battery may be a mixture of the bipolar battery of the present invention and a general battery (however, not all batteries are necessarily necessarily the battery of the present invention). As a result, an assembled battery that compensates for each other's weaknesses can be made by combining a bipolar battery that focuses on output and a general battery that focuses on energy, and the weight and size of the assembled battery can be reduced. The proportion of each bipolar battery and general battery to be mixed is determined according to the safety performance and output performance required for the assembled battery.

  FIG. 6 shows an assembled battery in which a bipolar battery A (42 V, 50 mAh) and a general battery B (4.2 V, 1 Ah) 10 series (42 V) are connected in parallel. The general battery B and the bipolar battery A have the same voltage, and a parallel connection is formed at that portion. The assembled battery 51 ′ has a structure in which the bipolar battery A has an output sharing and the general battery B has an energy sharing. This is a very effective means in an assembled battery in which it is difficult to achieve both output and energy. Also in this assembled battery 51 ', the tabs of the parallel portion and the portion of the general battery B adjacent in the horizontal direction in the figure are connected in series by the copper bus bar 56, and the general batteries B adjacent in the vertical direction of the drawing are connected in series. The parts to be connected were connected by vibration welding the tabs 39 and 40. The ends of the portion where the general battery B and the bipolar battery A are connected in parallel are connected to the terminals 62 and 64 to constitute positive and negative terminals. 5 except that the detection tab 60 for detecting the voltage of each layer of the bipolar battery A is taken out on both sides of the bipolar battery A, and the detection lines (not shown) are taken out at the front part of the assembled battery 51 ′. Therefore, the same members are denoted by the same reference numerals. Specifically, in order to form the assembled battery 51 ′ shown in FIG. 6, 10 general batteries B were sequentially connected from the end by the bus bar 56 and vibration welded and connected in series. Furthermore, the bipolar battery A and the general battery B at both ends connected in series are connected in parallel by the bus bar 56 and accommodated in a metal assembled battery case 55. In this way, by connecting an arbitrary number of bipolar batteries A in series and parallel, an assembled battery 51 ′ that can handle a desired current, voltage, and capacity can be provided. The assembled battery 50 ′ also has a positive electrode terminal 62 and a negative electrode terminal 64 formed on the front side of the metal assembled battery case 55. After connecting the batteries A and B in series and parallel, for example, Each positive terminal 62 and negative terminal 64 are connected by a terminal lead 59. Further, the assembled battery 51 ′ has a detection tab terminal 54 made of a metal to monitor the battery voltage (the individual cell layers of the bipolar battery A, and the voltage between the terminals of the bipolar battery A and the general battery B). The battery case 55 is installed at the front side surface where the positive electrode terminal 62 and the negative electrode terminal 64 are provided. And all the detection tabs 60 of each bipolar battery A (and also general battery B) are connected to the detection tab terminal 54 via the detection line (not shown). In addition, an external elastic body 52 is attached to the lower part of the assembled battery case 55, and when a composite assembled battery is formed by stacking a plurality of assembled batteries 51 ′, the distance between the assembled batteries 51 ′ is maintained. In addition, vibration resistance, impact resistance, insulation, heat dissipation, and the like can be improved.

  In the assembled battery of the present invention, the above-mentioned bipolar battery is further connected in series and parallel to form a first assembled battery unit, and the voltage between the terminals of the first assembled battery unit is the same as that of the other two batteries other than the bipolar battery. There is no particular limitation such as forming a second assembled battery unit in which the secondary batteries are connected in series and parallel, and connecting the first assembled battery unit and the second assembled battery unit in parallel. .

  The other constituent requirements of the assembled battery are not limited at all, and the same constituent requirements as the assembled battery using the existing non-bipolar lithium ion secondary battery can be applied as appropriate. However, since the conventionally known constituent members and manufacturing techniques for assembled batteries can be used, the description thereof is omitted here.

  Next, at least two or more of the above-mentioned assembled batteries (vehicle submodules) are combined in series, parallel, or in series and parallel to form a combined battery (vehicle assembled battery). It is possible to meet the demand for output relatively inexpensively without producing a new assembled battery. That is, the composite assembled battery of the present invention comprises at least two or more assembled batteries (such as those composed only of the bipolar battery or non-bipolar battery of the present invention, or composed of the bipolar battery of the present invention and a non-bipolar battery). It is characterized in that it is connected in series, in parallel, or in series and parallel, and the specification of the assembled battery can be tuned by manufacturing a standard assembled battery and combining it into a composite assembled battery. Thereby, since it is not necessary to manufacture many assembled battery types with different specifications, the composite assembled battery cost can be reduced.

  As a composite assembled battery, for example, FIG. 7 is a schematic diagram of a composite assembled battery (42V, 6Ah) connected in parallel with an assembled battery (42V, 1Ah) 6 using the bipolar battery shown in FIG. Each assembled battery constituting the composite assembled battery is integrated by a connecting plate and a fixing screw, and an anti-vibration structure is formed by installing an elastic body between the assembled batteries. The tabs of the assembled battery are connected by a plate-like bus bar. That is, as shown in FIG. 7, in order to connect the six assembled batteries 51 in parallel to form the composite assembled battery 70, the tabs of the assembled batteries 51 provided on the lid of each assembled battery case 55 ( The positive electrode terminal 62 and the negative electrode terminal 64) are electrically connected using an external positive electrode terminal portion that is a plate-shaped bus bar, an assembled battery positive electrode terminal connecting plate 72 having an external negative electrode terminal portion, and an assembled battery negative electrode terminal connecting plate 74, respectively. To do. Further, a connecting plate 76 having an opening corresponding to the fixing screw hole is fixed to each screw hole (not shown) provided on both side surfaces of each assembled battery case 55 with a fixing screw 77, and The batteries 51 are connected to each other. Moreover, the positive electrode terminal 62 and the negative electrode terminal 64 of each assembled battery 51 are protected by a positive electrode and a negative electrode insulating cover, respectively, and are identified by color-coding into appropriate colors, for example, red and blue. Further, an anti-vibration structure is formed by installing an external elastic body 52 between the assembled batteries 51, specifically, at the bottom of the assembled battery case 55.

  Moreover, in the said composite assembled battery, it is desirable to connect the some assembled battery which comprises this so that attachment or detachment is possible respectively. As described above, in the composite assembled battery in which a plurality of assembled batteries are connected in series and parallel, even if some of the batteries and the assembled battery fail, the repair can be performed only by replacing the failed part.

  The vehicle according to the present invention is characterized in that the assembled battery and / or the composite assembled battery is mounted. This makes it possible to meet a large vehicle demand for space by using a light and small battery. By reducing the battery space, the weight of the vehicle can be reduced.

  As shown in FIG. 8, in order to mount the composite battery pack 70 on a vehicle (for example, an electric vehicle or the like), the composite assembled battery 70 is mounted under a seat (seat) in the center of the vehicle body of the electric vehicle 80. This is because if it is installed under the seat, the interior space and the trunk room can be widened. The place where the battery is mounted is not limited to under the seat, but may be under the floor of the vehicle, behind the seat back, under the rear trunk room, or in the engine room in front of the vehicle.

  In the present invention, not only the composite battery pack but also the battery pack may be mounted on the vehicle depending on the intended use, or the composite battery pack and the battery pack may be mounted in combination. Moreover, as a vehicle in which the composite assembled battery or the assembled battery of the present invention can be mounted as a driving power source or an auxiliary power source, the above hybrid car, electric vehicle, hybrid electric vehicle, fuel cell vehicle, hybrid fuel cell vehicle, etc. Although preferable, it is not limited to these. Further, as a vehicle on which the assembled battery and / or the composite assembled battery of the present invention can be mounted as, for example, a driving power source or an auxiliary power source, a hybrid car, an electric vehicle, a hybrid electric vehicle, a fuel cell vehicle, a hybrid fuel Although a battery car etc. are preferable, it is not restricted to these.

  Hereinafter, the content of the present invention will be described with reference to examples and comparative examples, but the present invention is not limited to these examples. In the following examples and comparative examples, unless otherwise specified, the bipolar electrode prepared (formed) in the following steps 1 to 3, the gel electrolyte layer having a separator, and the laminated battery are used. The same explanation is omitted.

Procedure 1. Production of a bipolar (bipolar) type electrode A positive electrode slurry is applied to one side of a current collector SUS foil (thickness 10 μm), a negative electrode slurry is applied to the opposite side, and a positive electrode active material layer and a negative electrode active material are formed on both sides of the SUS foil. A bipolar electrode coated with the layer was formed.

Procedure 2. Formation of Gel Electrolyte Layer A polypropylene non-woven fabric (thickness 50 μm) was used for the separator.

  In this nonwoven fabric made of polypropylene (thickness 50 μm), 5% by weight of a monomer solution (copolymer of polyethylene oxide and polypropylene oxide) having an average molecular weight of 7500 to 9000 which is a precursor of an ion conductive polymer matrix, as an electrolyte solution PC + EC (PC: EC = 1: 1 (volume ratio)) 95% by weight, 1.0M LiBETI, polymerization initiator (BDK; host polymer (polymer raw material of polymer gel electrolyte) ion conductive polymer matrix) A gel polymer composed of a separator containing a gel electrolyte by immersing a pregel solution composed of 0.01 to 1% by mass with respect to the precursor, sandwiching it in a quartz glass substrate and irradiating ultraviolet rays for 15 minutes to crosslink the precursor. An electrolyte layer was obtained.

Procedure 3. Laminated battery After the sealing material is disposed around the positive electrode active material layer of the bipolar electrode prepared in Step 1 and heat and pressure are applied to fuse the current collector and the sealing material, the positive and negative electrode actives of the bipolar electrode are obtained. A pregel solution was applied on the material layer and thermally crosslinked to impregnate and hold the gel electrolyte in the positive and negative electrode active material layers. Three layers of the bipolar electrode impregnated and held with the gel electrolyte and a separator (gel polymer electrolyte layer) containing the gel electrolyte are alternately laminated, and the periphery of the negative electrode active material layer of the opposing current collector by applying heat and pressure. The laminated battery was formed by fusing the part and the sealing material.

Example 1
First, the positive electrode active material layer of the bipolar electrode according to the procedure 1 (without polymer gel electrolyte impregnation) is LiMn ₂ O ₄ (positive electrode active material), acetylene black (conducting aid), PVdF (binder) (weight) A positive electrode slurry having a mixing ratio of 85: 5: 10) was applied to one side of the current collector by a self-propelled die coater and pressed to a film thickness of 15 μm. Next, a positive electrode slurry composed of a mixture ratio of LiMn ₂ O ₄ , activated carbon (gas adsorbent), acetylene black, and PVdF (weight ratio 82: 3: 5: 10) is applied on the self-propelled die coater. It was produced by pressing so as to have a thickness of 15 μm. The positive electrode active material layer thus obtained (in the state of no polymer gel electrolyte impregnation) is an active material layer containing no gas adsorbent on the current collector and an active material containing the gas adsorbent thereon. It has a two-layer structure in which layers are laminated in order.

  The negative electrode active material layer (the polymer gel electrolyte non-impregnated state) of the bipolar electrode according to Procedure 1 is composed of hard carbon (negative electrode active material), VGCF (conducting aid), PVdF (binder) (weight ratio 85: 5: A negative electrode slurry having a mixing ratio of 10) was applied to the opposite surface of the current collector with a self-propelled die coater and pressed to a film thickness of 30 μm. Thereby, the bipolar electrode was formed.

  In addition, the positive electrode slurry and negative electrode slurry which consisted of the mixing ratio of each above-mentioned component used what added and stirred N-methyl-2-pyrrolidone (NMP) as a solvent further to each above-mentioned component.

  The thicknesses of the positive electrode active material layer and the negative electrode active material layer of the bipolar electrode after pressing were both set to 30 μm.

  A separator (gel polymer electrolyte layer) containing the gel electrolyte according to the above procedure 2 is sandwiched between bipolar electrodes impregnated and held with the gel electrolyte according to the above procedure 3, and after the formation of the laminated battery, the initial charge / discharge is performed. It was measured.

Example 2
First, the positive electrode active material layer of the bipolar electrode according to the procedure 1 (the polymer gel electrolyte non-impregnated state) is LiMn ₂ O ₄ (positive electrode active material), acetylene black (conductive aid), PVdF (binder) ( A positive electrode slurry having a mixing ratio of 85: 5: 10) was applied to one side of the current collector with a self-propelled die coater and pressed to a film thickness of 15 μm. Next, a positive electrode slurry having a mixed ratio of LiMn ₂ O ₄ , activated carbon, acetylene black, and PVdF (weight ratio 80: 5: 5: 10) is applied on the self-propelled die coater so that the film thickness becomes 15 μm. It was produced by pressing. The positive electrode active material layer thus obtained (in the state of no polymer gel electrolyte impregnation) is an active material layer containing no gas adsorbent on the current collector and an active material containing the gas adsorbent thereon. It has a two-layer structure in which layers are laminated in order.

  And the laminated battery similar to Example 1 was formed except having used the positive electrode active material layer obtained in this way.

Example 3
The positive electrode active material layer (the polymer gel electrolyte non-impregnated state) of the bipolar electrode according to the procedure 1 is first composed of a mixing ratio of LiMn ₂ O ₄ , acetylene black and PVdF (weight ratio 85: 5: 10). The positive electrode slurry was applied to one side of the current collector with a self-propelled die coater and pressed to a film thickness of 15 μm. Next, a positive electrode slurry having a mixture ratio of LiMn ₂ O ₄ , activated carbon, acetylene black, and PVdF (weight ratio 83: 2: 5: 10) is applied by a self-propelled die coater so that the film thickness becomes 15 μm. It was produced by pressing. The positive electrode active material layer thus obtained (in the state of no polymer gel electrolyte impregnation) is an active material layer containing no gas adsorbent on the current collector and an active material containing the gas adsorbent thereon. It has a two-layer structure in which layers are laminated in order.

  And the battery similar to Example 1 was formed except having used the positive electrode active material layer obtained in this way.

Example 4
The positive electrode active material layer (the polymer gel electrolyte non-impregnated state) of the bipolar electrode according to the procedure 1 is first composed of a mixing ratio of LiMn ₂ O ₄ , acetylene black and PVdF (weight ratio 85: 5: 10). The positive electrode slurry was applied to one side of the current collector with a self-propelled die coater and pressed to a film thickness of 15 μm. Next, a positive electrode slurry having a mixed ratio of LiMn ₂ O ₄ , activated carbon, acetylene black, and PVdF (weight ratio 78: 7: 5: 10) is applied on the self-propelled die coater so as to have a film thickness of 15 μm. It was produced by pressing. The positive electrode active material layer thus obtained (in the state of no polymer gel electrolyte impregnation) is an active material layer containing no gas adsorbent on the current collector and an active material containing the gas adsorbent thereon. It has a two-layer structure in which layers are laminated in order.

  And the battery similar to Example 1 was formed except having used the positive electrode active material layer obtained in this way.

Example 5
The positive electrode active material layer (the polymer gel electrolyte non-impregnated state) of the bipolar electrode according to the procedure 1 is first composed of a mixing ratio of LiMn ₂ O ₄ , acetylene black and PVdF (weight ratio 85: 5: 10). The positive electrode slurry was applied to one side of the current collector with a self-propelled die coater and pressed to a film thickness of 15 μm. Next, a positive electrode slurry having a mixed ratio of LiMn ₂ O ₄ , activated carbon, acetylene black, and PVdF (weight ratio 84: 1: 5: 10) is applied on the self-propelled die coater so that the film thickness becomes 15 μm. It was produced by pressing. The positive electrode active material layer thus obtained (in the state of no polymer gel electrolyte impregnation) is an active material layer containing no gas adsorbent on the current collector and an active material containing the gas adsorbent thereon. It has a two-layer structure in which layers are laminated in order.

  And the battery similar to Example 1 was formed except having used the positive electrode active material layer obtained in this way.

Example 6
First, the positive electrode active material layer of the bipolar electrode according to the procedure 1 (with the polymer gel electrolyte not impregnated) is made of LiMn ₂ O ₄ , activated carbon, acetylene black, PVdF (weight ratio 82: 3: 5: 10). A positive electrode slurry having a mixing ratio was applied to one side of the current collector by a self-propelled die coater and pressed to a film thickness of 15 μm. Next, a positive electrode slurry having a mixture ratio of LiMn ₂ O ₄ , acetylene black, and PVdF (weight ratio 85: 5: 10) is applied from above with a self-propelled die coater, and pressing is performed so that the film thickness becomes 15 μm. Made. The positive electrode active material layer thus obtained (in the state of no polymer gel electrolyte impregnation) has an active material layer containing a gas adsorbent on the current collector and an active material containing no gas adsorbent on the active material layer. It has a two-layer structure in which layers are laminated in order.

  And the battery similar to Example 1 was formed except having used the positive electrode active material layer obtained in this way.

Example 7
First, the positive electrode active material layer of the bipolar electrode according to the procedure 1 (with the polymer gel electrolyte not impregnated) is made of LiMn ₂ O ₄ , activated carbon, acetylene black, PVdF (weight ratio 82: 3: 5: 10). A positive electrode slurry having a mixing ratio was applied to one side of the current collector by a self-propelled die coater and pressed to a film thickness of 10 μm. Next, a positive electrode slurry having a mixture ratio of LiMn ₂ O ₄ , acetylene black, and PVdF (weight ratio 85: 5: 10) was applied from above with a self-propelled die coater, and pressed to a thickness of 10 μm. . Furthermore, a positive electrode slurry comprising a mixed ratio of LiMn ₂ O ₄ , activated carbon, acetylene black, and PVdF (weight ratio 82: 3: 5: 10) is applied by a self-propelled die coater, and a press is applied so that the film thickness becomes 10 μm. Made to go. The positive electrode active material layer thus obtained (in the state of no polymer gel electrolyte impregnation) has an active material layer containing a gas adsorbent on the current collector and an active material containing no gas adsorbent on the active material layer. It has a three-layer structure in which a layer and an active material layer containing a gas adsorbent on the layer are sequentially laminated.

  And the battery similar to Example 1 was formed except having used the positive electrode active material layer obtained in this way.

Comparative Example 1
The positive electrode active material layer (non-polymer gel electrolyte impregnated state) of the bipolar electrode according to the procedure 1 is a positive electrode slurry having a mixing ratio of LiMn ₂ O ₄ , acetylene black and PVdF (weight ratio 85: 5: 10). Was applied to one side of the current collector with a self-propelled die coater and pressed to a thickness of 30 μm. The positive electrode active material layer thus obtained (in the state of no polymer gel electrolyte impregnation) has a single layer (one layer) structure in which only an active material layer not containing a gas adsorbent is laminated on a current collector. It is what you have.

  And the battery similar to Example 1 was formed except having used the positive electrode active material layer obtained in this way.

Comparative Example 2
The positive electrode active material layer of the bipolar electrode according to the above procedure 1 (without polymer gel electrolyte impregnation) is a mixture ratio of LiMn ₂ O ₄ , activated carbon, acetylene black, PVdF (weight ratio 82: 3: 5: 10). A positive electrode slurry made from the above was applied to one side of the current collector with a self-propelled die coater and pressed to a thickness of 30 μm. The positive electrode active material layer thus obtained (in the state of no polymer gel electrolyte impregnation) has a single layer (one layer) structure in which only an active material layer containing a gas adsorbent is laminated on a current collector. It is what has.

  And the battery similar to Example 1 was formed except having used the positive electrode active material layer obtained in this way.

Comparative Example 3
The positive electrode active material layer (the polymer gel electrolyte non-impregnated state) of the bipolar electrode according to the procedure 1 is first composed of a mixing ratio of LiMn ₂ O ₄ , acetylene black and PVdF (weight ratio 85: 5: 10). The positive electrode slurry was applied to one side of the current collector with a self-propelled die coater and pressed to a film thickness of 15 μm. Next, the activated carbon, acetylene black, PVdF (weight ratio 30:50:20) so that the weight ratio of the activated carbon is 3.66% with respect to the amount of active material in the active material layer not containing activated carbon. A positive electrode slurry having a mixing ratio was applied by a self-propelled die coater and pressed to a film thickness of 15 μm. The positive electrode active material layer thus obtained (in the state of no polymer gel electrolyte impregnation) is formed by sequentially laminating an active material layer not containing a gas adsorbent on the current collector and a positive electrode gas adsorbent layer thereon. It has a two-layer structure.

  And the battery similar to Example 1 was formed except having used the positive electrode active material layer obtained in this way.

[Battery evaluation]
A charge / discharge test was performed on each of the batteries of Examples 1 to 7 and Comparative Examples 1 to 3. In the experiment, the constant voltage (CC) of the total voltage of the three-layer laminated battery was 12.6V at a current of 0.5C, and then the constant voltage charge (CV) was performed. The battery was discharged to a total voltage of 7.5V.

  After the first charge / discharge, the battery internal resistance in the discharged state was measured. From the measurement results, the ratio (ratio) of the resistance values of Examples 1 to 7 and Comparative Examples 1 to 3 based on the resistance value of Comparative Example 1 as “resistance value / comparative example 1 resistance value” is shown in Table 1. Show. Table 1 also shows, as “capacity value / capacitance value of comparative example 1”, initial charge / discharge of each of Examples 1 to 7 and Comparative Examples 1 to 3 based on the discharge capacity value at the time of initial charge / discharge of Comparative Example 1. The ratio (ratio) of the discharge capacity value at the time is shown. Further, in Table 1, as "relative output with respect to comparative example 1," the outputs at the time of initial charge / discharge of each of Examples 1 to 7 and Comparative Examples 1 to 3 based on the output value at the time of initial charge / discharge of comparative example 1 Indicates the value ratio.

  Then, in Examples 1-3, 6, 7, and Comparative Examples 1-3, 100 cycles of charging / discharging was performed with the electric current of 1C, and the swelling of the laminated battery in the discharge state was confirmed visually. The results are shown in Table 1. In Table 1, “X” (defective) was indicated for the battery that was confirmed to be swollen after 100 cycles, and “◯” (good) was indicated for the battery that was not confirmed to be swollen after 100 cycles.

  As shown in Table 1 above, when Example 1 and Comparative Example 1 are compared, by providing an active material layer containing activated carbon as a gas adsorbent at the active material layer / electrolyte layer interface, the internal resistance of the battery decreases, and the initial charge It was confirmed that the gas sometimes generated was adsorbed in the activated carbon.

  When Example 1 and Comparative Example 2 were compared, the resistance values were almost the same. However, in Comparative Example 2, the adsorbent was added to the entire active material layer, so the value was lower than that of Example 1. It was confirmed that a high-power, high-capacity battery can be designed by adding the gas adsorbent to the active material layer / electrolyte layer interface instead of adding it to the entire active material layer.

  When Example 1 and Comparative Example 3 were compared, the resistance values were almost the same. However, in Comparative Example 3, the active material layer is not provided in the layer containing the adsorbent, so it can be seen that the battery capacity is reduced by about 50% compared to Comparative Example 1, and the layer provided with the gas adsorbent also contains the active material. It was confirmed that a battery with high output and high capacity could be designed.

  When Examples 1 to 5 were compared, it was confirmed that Example 2 had the largest decrease in resistance value. In Example 4, although the amount of adsorbent added was increased from that in Example 2, the resistance value was almost the same as in Example 2. The battery capacity of Example 4 was the lowest value. On the other hand, since the resistance value in Example 5 was almost the same as that in Comparative Example 1, the active material layer / electrolyte was added in an amount of 2 to 7 wt% of activated carbon with respect to the amount of active material in the active material layer containing the adsorbent. It was confirmed that the battery can be adsorbed at the layer interface and a battery with high output and high capacity was designed.

  A comparison between Examples 1 and 6 shows that there was no significant difference in resistance value or battery capacity, so that the gas adsorbent was placed at either the active material layer / electrolyte layer interface or the active material layer / current collector interface. I found it effective.

  When Examples 1, 6, and 7 were compared, it was found that the internal resistance value of Example 7 was the smallest. For this reason, by providing a layer containing an adsorbent on both the active material layer / electrolyte interface and the active material layer / current collector interface, it becomes possible to adsorb the gas accumulated at each interface, resulting in high output and high capacity. It was confirmed that the battery could be designed.

  When Example 7 and Comparative Example 2 are compared, an adsorbent is provided on the entire electrode active material layer, and an active material layer / electrolyte layer and an active material layer / current collector interface are provided with a layer containing an adsorbent to each interface. It was confirmed that it was possible to adsorb the gas accumulated in the battery and to design a battery with high output and high capacity.

  As a result of confirming battery swelling after 100 cycles of charge and discharge in Examples 1 to 3, 6, 7 and Comparative Examples 1 to 3, battery swelling was confirmed in Comparative Example 1, but battery swelling was confirmed in other cases. There wasn't. Therefore, by providing a gas adsorbent in the active material, it is possible to adsorb not only the gas generated during the initial charge / discharge but also the long-term use of the battery, and in particular, the active material layer / electrolyte, the active material layer / collection. It was confirmed that a battery with a high output and a high capacity can be designed by providing an adsorbent at the electrical interface.

FIG. 1A is a schematic cross-sectional view schematically showing a unit cell structure when a gas adsorbent-containing active material layer is provided at the active material layer / electrolyte layer interface. FIG. 1B is a schematic cross-sectional view schematically showing a unit cell structure when a gas adsorbent-containing active material layer is provided at the active material layer / current collector interface. FIG. 1C is a schematic cross-sectional view schematically showing a unit cell structure when the gas adsorbent-containing active material layer is provided at both the active material layer / electrolyte layer interface and the active material layer / current collector interface. FIG. FIG. 2 schematically shows an electrode laminate (bipolar battery main body) of a bipolar flat type (laminated type) lithium ion secondary battery obtained by laminating three cell structures of FIG. 1A. FIG. 1 is a schematic cross-sectional view of a flat (stacked) lithium ion secondary battery using a non-bipolar electrode. 1 is a schematic cross-sectional view schematically showing the overall structure of a flat (stacked) lithium ion secondary battery using bipolar electrodes. It is a schematic diagram which shows an example of the assembled battery which connected the bipolar battery of this invention in 2 series 20 parallel. 5 (a) is a plan view of the assembled battery, FIG. 5 (b) is a front view of the assembled battery, and FIG. 5 (c) is a right side view of the assembled battery. In (c), all show the inside of the assembled battery through the outer case so that it can be seen that the bipolar batteries are connected in series and in parallel. It is a figure which shows an example of the assembled battery which connected in parallel the bipolar battery A of this invention and the lithium ion secondary battery B10 which is not the bipolar type of this invention. FIG. 6A is a plan view of the assembled battery, FIG. 6B is a front view of the assembled battery, and FIG. 6C is a right side view of the assembled battery. In (c), the inside of the assembled battery is shown through the outer case so that it can be seen that the bipolar battery A and the non-bipolar lithium ion secondary battery B are connected in series and parallel mixing. . It is a figure which shows an example of the composite assembled battery of this invention. FIG. 7A is a plan view of the composite assembled battery, FIG. 7B is a front view of the composite assembled battery, and FIG. 7C is a right side view of the composite assembled battery. It is a schematic diagram which shows the electric vehicle of the state which mounts a composite assembled battery. It is explanatory drawing explaining the absolute maximum length used when measuring the particle size of particle | grains.

Explanation of symbols

11 cell layer,
12 Current collector,
13 positive electrode active material layer,
13a positive electrode active material layer not containing a gas adsorbent,
13b Gas adsorbent-containing active material layer on the positive electrode side,
15 negative electrode active material layer,
15a negative electrode active material layer not containing a gas adsorbent,
15b Gas adsorbent-containing active material layer on the negative electrode side,
31 Monopolar lithium ion secondary battery,
32 Battery exterior material,
33 positive electrode current collector,
34 positive electrode active material layer,
35 electrolyte layer,
36 negative electrode current collector,
37 negative electrode active material layer,
38 Power generation elements,
39 Positive electrode (terminal) lead,
40 Negative electrode (terminal) lead,
41 Bipolar lithium ion secondary battery (bipolar battery),
42 current collector,
43 positive electrode active material layer,
44 negative electrode active material layer,
45 Bipolar electrode,
45a, the uppermost electrode of the electrode stack,
45b, the bottom electrode of the electrode stack,
46 electrolyte layer,
47 electrode laminate (bipolar battery body),
48 positive lead,
49 Negative lead,
50 Battery exterior material (exterior package),
51, 51 'battery pack,
52 external elastic body,
53 detection lines,
54 detection tab terminal,
55 battery pack case,
56, 58 Busbar,
59 Terminal lead,
62 positive terminal,
64 negative terminal,
70 composite battery pack,
72 composite battery positive electrode terminal connecting plate,
74 composite battery negative electrode terminal plate,
76 connecting plate,
77 fixing screws,
80 electric car,
91 particles (including irregular particles)
L Maximum length.

Claims (9)

In a lithium ion secondary battery having a structure in which a positive electrode active material layer is provided on one current collector and an electrode in which a negative electrode active material layer is provided on the other current collector through an electrolyte layer,
An active material layer containing a gas adsorbent is formed on at least one surface of the active material layer.   The lithium ion secondary battery according to claim 1, wherein the electrolyte layer is made of a polymer electrolyte and / or a gel electrolyte.   In the electrode, at least one of the active material layers has a structure in which an active material layer not containing the gas adsorbent and an active material layer containing a gas adsorbent at the active material layer / electrolyte layer interface are provided. The lithium ion secondary battery according to claim 1 or 2.   In the electrode, at least one active material layer has a structure in which an active material layer not containing the gas adsorbent and an active material layer containing a gas adsorbent at the active material layer / current collector interface are provided. The lithium ion secondary battery according to claim 1 or 2, characterized in that:   In the electrode, at least one of the active material layers includes an active material layer not containing the gas adsorbent, an active material layer containing a gas adsorbent at the active material layer / electrolyte layer interface, and an active material layer / current collector. 3. The lithium ion secondary battery according to claim 1, further comprising: an active material layer containing an adsorbent at a body interface. 4.   6. The lithium ion secondary material according to claim 1, wherein the active material layer containing the gas adsorbent is a layer containing more carbon material than at least adjacent active material layers. Next battery.   The lithium ion secondary material according to any one of claims 1 to 6, wherein the gas adsorbent is at least one carbon material selected from the group consisting of activated carbon, carbon nanotubes, and carbon sheets. Next battery.   The lithium ion secondary material according to any one of claims 1 to 7, wherein the gas adsorbent has a content of 7 wt% or less with respect to a total amount of the active material layer containing the gas adsorbent. Next battery. The positive electrode active material includes a lithium-transition metal oxide,
Item 9. The lithium ion secondary battery according to any one of Items 1 to 8, wherein a carbon material or a lithium-transition metal compound is used for the negative electrode active material.

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