JP2009302074A - Electrode for secondary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode for a secondary battery, in which the local temperature rise in the battery interior can be prevented even in charge/discharge at a high output, at a high voltage and a large current. <P>SOLUTION: The electrode for a secondary battery is configured such that an electrode layer on a substrate is composed of a plurality of fine cells having different resistance values or capacities. Further, the fine cells are arranged such that the resistance values or capacities are two-dimensionally or one-dimensionally gradient so that the electrode layer relaxes a stress and/or a thermal stress. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a small high-power secondary battery, and more particularly to a secondary battery suitable as a motor driving battery for an electric vehicle or the like by combining a plurality of secondary batteries.

  In recent years, in order to promote the introduction of electric vehicles (EV), hybrid vehicles (HEV), and fuel cell vehicles (FCV) against the backdrop of an increase in environmental protection movement, these motor drive batteries have been developed. For this purpose, a rechargeable secondary battery is used. In applications that require high output and high energy density, such as EV, HEV, and FCV motor drives, a single large battery cannot be made in practice, and an assembled battery composed of a plurality of batteries connected in series. It was common to use. In addition, it has been proposed to use a thin laminated battery as one battery constituting such an assembled battery (see, for example, Patent Document 1).

  This thin laminated battery is a battery in which an outer container of a lithium ion battery is replaced with a metal sheet material. Specifically, a metal thin film such as aluminum foil and a resin film that physically protects a metal thin film such as polyethylene terephthalate and heat fusion such as an ionomer so that gas such as water vapor and oxygen is not exchanged inside and outside the container. A laminate sheet in which adhesive resin films are stacked to form a multilayer is used.

  The outer container has a rectangular shape in a plan view and has a predetermined thin shape. A plate-like positive electrode and negative electrode are inserted into an outer container, and a liquid electrolyte is sealed to form a battery.

  Such a thin laminate type battery is lightweight because it does not have an individual metal outer container, and even when the pressure inside the container becomes high due to overcharge or the like, the impact is higher than that of a metal container. Since there are few, it is suitable as a motor drive battery.

JP2003-151526A

  However, in such a thin laminate battery, when manufacturing a positive electrode and a negative electrode, the following problems occur because the positive electrode material and the negative electrode material are applied to the current collector foil by a coater or the like.

  That is, it is excellent in that a positive electrode layer and a negative electrode layer having a uniform thickness can be formed on a current collector foil by applying a positive electrode material and a negative electrode material with a coater, and is further formed on a single current collector foil. The composition or configuration inside the electrode layer is uniform without local bias, and is an excellent electrode coating method that can provide an extremely homogeneous electrode. However, in the laminated battery used for applications that require a high capacity, a high voltage and a large current such as a power source for driving a vehicle, a type in which a plurality of such electrodes are stacked or wound is used. In such a laminated or wound laminate battery, heat is more likely to accumulate in the central portion (center portion) than in the peripheral portion (outer peripheral portion) of the electrode due to heat generation during charging / discharging with a large current. When heat is trapped, the internal resistance of the portion decreases, and when the internal resistance decreases, current easily flows through the portion. Heat generation is further promoted by a large amount of current flowing through the part, and if the heat generation is promoted, the internal resistance is further lowered than the peripheral part. It causes the short circuit phenomenon by.

  Therefore, an object of the present invention is to use an electrode for a secondary battery that can prevent a local temperature rise inside the battery even when charging / discharging with a high output, a high voltage and a large current, and the same. It is to provide a battery and a manufacturing method thereof.

  In the present invention, the electrode layer on the substrate is composed of a plurality of microcells having different resistance values or capacities, and the resistance value or capacity is graded two-dimensionally or one-dimensionally so that the electrode layer relieves stress or thermal stress. This can be achieved by a secondary battery electrode in which microcells are arranged.

  According to the present invention, as an electrode for a secondary battery, a microcell is formed such that a resistance value or a capacity is inclined two-dimensionally or one-dimensionally so that an electrode layer on a substrate relaxes stress and / or thermal stress. Even if the battery temperature varies widely from low temperature to high temperature, even when the thermal expansion coefficients of the current collecting layer, positive and negative electrode layers, and ion conduction layer are different, Eliminate the thermal distortion in the plane direction = the direction perpendicular to the thickness direction; for example, the plane direction formed by the XY axes in FIG. 1, and apply a conventional coater to form a uniform electrode layer of several tens of mm or more Compared with the case, the generation | occurrence | production of the crack etc. in an electrode or the distortion of a current collection layer can be prevented significantly. As a result, it is possible to provide an electrode for a secondary battery that can prevent a local temperature rise inside the battery and achieve a long life even when charging and discharging with a high output, a high voltage and a large current.

A specific embodiment of the electrode for a secondary battery according to the present invention is a configuration example in which a plurality of micro cells are arranged on a substrate, and can relieve stress at the time of electrode formation and / or thermal stress due to temperature change. FIG. 3 is a schematic plan view schematically illustrating a two-dimensional tile-like arrangement of micro cells. FIG. 2 is a schematic side view schematically illustrating a state of a part of an electrode laminated structure of a secondary battery configured using the secondary battery electrode of FIG. 1. FIG. 3 is an explanatory diagram schematically showing a state in which the secondary battery of FIG. 2 is bent and installed so that the secondary battery is installed in close contact with a surface having a curvature. A specific embodiment of the electrode for a secondary battery according to the present invention is a configuration example in which a plurality of micro cells are arranged on a substrate, and can relieve stress at the time of electrode formation and / or thermal stress due to temperature change. It is the plane schematic which represented typically another arrangement | positioning of the two-dimensional tile shape of a micro cell. FIG. 5 is a schematic side view schematically illustrating a state of a part of an electrode laminated structure of a secondary battery configured using the secondary battery electrode of FIG. 4. A specific embodiment of the electrode for a secondary battery according to the present invention is a configuration example in which a plurality of micro cells are arranged on a substrate, and can relieve stress at the time of electrode formation and / or thermal stress due to temperature change. It is the plane schematic which represented typically another arrangement | positioning of the two-dimensional tile shape of a micro cell. FIG. 6 is a schematic side view schematically showing a state of a part of an electrode laminated structure of a secondary battery configured using the secondary battery electrode of FIG. 5. A specific embodiment of the electrode for a secondary battery according to the present invention is a configuration example in which a plurality of micro cells are arranged on a substrate, and can relieve stress at the time of electrode formation and / or thermal stress due to temperature change. FIG. 5 is a schematic plan view schematically showing another different arrangement of two-dimensional tiles of micro cells. A specific embodiment of the electrode for a secondary battery according to the present invention is a configuration example in which a plurality of micro cells are arranged on a substrate, and can relieve stress at the time of electrode formation and / or thermal stress due to temperature change. FIG. 6 is a schematic plan view schematically showing still another different arrangement of two-dimensional tiles of micro cells. As a specific embodiment of the electrode for a secondary battery of the present invention, by disposing minute cells having different resistance values on a substrate, it is possible to distribute current and relieve thermal stress due to temperature change. FIG. 3 is a schematic plan view schematically illustrating a two-dimensional tile-like arrangement of micro cells. As a specific embodiment of the electrode for a secondary battery according to the present invention, the subdivided microcells having different resistance values are arranged two-dimensionally or one-dimensionally in an inclined manner so as to achieve uniform temperature distribution. FIG. 2 is a schematic plan view schematically showing a two-dimensional arrangement of microcells that can alleviate thermal stress due to temperature changes. As a specific embodiment of the electrode for a secondary battery of the present invention, a configuration example in which a plurality of micro cells are arranged on a substrate, and a material having good thermal conductivity is arranged in a gap between the micro cells, FIG. 3 is a schematic plan view schematically showing a two-dimensional tile-like arrangement of microcells that can quickly move heat and mitigate temperature changes. It is the side schematic diagram which represented typically the mode of the one part electrode laminated structure of the secondary battery comprised using the electrode for secondary batteries of FIG. It is the cross-sectional schematic which represented typically the basic structure of the polymer lithium ion secondary battery which is one of the suitable aspects of the secondary battery of this invention. It is the cross-sectional schematic which represented typically the basic structure of the bipolar type polymer lithium ion secondary battery which is one of the more suitable aspects of the secondary battery of this invention.

  Hereinafter, embodiments of the present invention will be described.

  In the secondary battery electrode according to the present invention, the electrode layer on the substrate is composed of a plurality of microcells having different resistance values or capacities, and the resistance value is reduced so that the electrode layer relieves stress and / or thermal stress. Alternatively, the minute cells are arranged so that the capacity is two-dimensionally or one-dimensionally inclined. Thereby, the stress at the time of electrode formation and the thermal stress at the time of charging / discharging (at the time of high temperature) can be relieved, the distortion of an electrode can be eliminated, and the crack etc. to an electrode layer can be prevented. In addition, the electrode layer can be prevented from peeling or falling off from the substrate due to cracks or strain, and the battery life can be extended.

  Here, the base includes a current collecting layer, an ion conductive layer, a separator (non-ion conductive material), an electrode terminal (tab), an appropriate release film other than battery constituent members, and the like.

  The ion conductive layer is a broad concept including an existing electrolyte layer, and includes an electrolyte layer in which a separator is impregnated with an electrolytic solution, a solid polymer or a gel polymer, and a solid polymer or a gel polymer.

  With the said electrode layer, let a positive electrode layer and / or a negative electrode layer be an electrode layer.

  The secondary battery electrode of the present invention includes a bipolar electrode in addition to a positive electrode and a negative electrode. Therefore, depending on the bipolar electrode structure, in addition to the positive electrode layer and the negative electrode layer, a current collecting layer and an ion conductive layer are also included in the constituent members of the secondary battery electrode of the present invention. That is, the positive electrode is a non-bipolar secondary battery electrode, the positive electrode has a base, for example, a structure in which a positive electrode layer (negative electrode layer) is formed on both sides of the current collecting layer, and the negative electrode is a base, for example, a current collecting layer In this structure, a positive electrode layer (negative electrode layer) is formed on both sides of the substrate. On the other hand, a bipolar secondary battery electrode, that is, a bipolar electrode has a structure in which a positive electrode layer is formed on one surface of a substrate, for example, a current collecting layer or an ion conductive layer, and a negative electrode layer is formed on the other surface.

  In the present specification, the unit cell structure means an ion conductive layer, a positive electrode layer and a negative electrode layer sandwiching the ion conductive layer, and is common to both a bipolar battery and a non-bipolar battery. It is a concept.

  In addition, the stress corresponds to stress at the time of electrode formation, stress generated by installation on a surface having a curvature, stress generated by vibration / impact during driving of the vehicle, and the like.

  The thermal stress corresponds to thermal stress due to temperature change such as during charging and discharging. Therefore, in the electrode for a secondary battery of the present invention, for example, in a battery mounted as a driving power source for a vehicle, in a cold district or the like, the battery is rapidly charged / discharged from the low temperature before starting charging / discharging. In order to sufficiently apply to the thermal stress when the battery temperature changes widely from low temperature to high temperature, such as when reaching high temperature, the optimal electrode layer arrangement is made according to the intended use. desirable.

  That is, the arrangement (pattern) of the electrode layer on the substrate is not limited as long as it can relieve stress and / or thermal stress. For example, (i) plane direction (X in FIG. 1) -Two-dimensional planar arrangement in the Y-axis direction), (ii) Arrangement in the thickness direction (Z-axis direction in FIG. 2), and (iii) Three-dimensional three-dimensional arrangement combining them. May be included.

  As a specific embodiment of the electrode for a secondary battery of the present invention, a micro cell (hereinafter also referred to as a small electrode) in which an electrode layer is finely divided so as to relieve stress and / or thermal stress is formed on a substrate. A plurality of them are arranged continuously and / or spaced apart. As a result, thermal strain can be released to the gaps between the microcells. As a result, stress at the time of electrode formation and thermal stress at the time of charge / discharge (at high temperature) can be relieved, distortion of the electrode can be eliminated, and cracks to the electrode layer can be prevented. Further, it is possible to prevent the electrode layer from being peeled off or detached from the substrate due to cracks or strains, thereby extending the life. Further, by arranging the minute cells with a gap, the entire electrode becomes flexible and can be bent with respect to the X axis or Y axis in FIG. For this reason, as shown in FIG. 3, even if the battery mounting surface is a surface 33 having a curvature in a certain direction, the battery (35) using the main electrode 31, in particular, the main electrode 31 can be bent. It can be installed along a surface 33 having a curvature (see FIG. 3). For this reason, it is excellent in that it can be dissipated by heat radiation from the entire battery to the surface having the curvature substantially uniformly by being brought into close contact with the surface having the curvature. That is, when a uniform electrode layer is formed as in the prior art, bending the electrode does not cause cracks, cracks, or the like in the electrode layer, thereby causing no deterioration in battery performance. In addition, when the electrode is not bent on the surface having curvature, the battery is not stable and weak against vibrations and shocks. In addition, the contact surface and the non-contact portion between the surface having the curvature and the battery However, in a battery having a structure in which an electrode can be brought into close contact with a surface having a curvature as in the present invention, there is a tendency that a temperature difference is likely to occur inside the battery. Good battery performance can be exhibited without any problems. Furthermore, since the installation space when the battery is mounted on the vehicle is not easily restricted, there is an advantage that the degree of freedom in designing the battery shape and the like is widened.

  Moreover, the said micro cell means one division (cell) of each subdivision of the electrode layer formed finely divided into two or more on the base-material surface (XY axis plane of FIG. 1).

  The planar shape of the microcell (the shape when viewed in the XY axis plane of FIG. 1) is not particularly limited as long as it can be arranged so as to relieve stress and / or thermal stress. For example, a polygonal shape such as a triangle, a quadrangle, a pentagon, and a hexagon, and a regular shape such as a circle, an ellipse, and a cross shape may be mentioned, but the shape is not limited to these and may be an irregular shape. The planar shape of each micro cell arranged on the substrate may be the same shape or two or more different shapes. In addition, in the several electrode which comprises a battery, the planar shape of a micro cell may be the same shape for every electrode, and a different shape for every electrode may be sufficient as it.

  The size of the microcell (size when viewed on the XY axis plane in FIG. 1 = area) should be particularly limited if it can be arranged so as to relieve stress and / or thermal stress. Instead, all the micro cells arranged on the substrate may have the same size or two or more different sizes. In the plurality of electrodes constituting the battery, the size of the micro cell may be the same for each electrode, or may be different for each electrode.

  The composition and material of the constituent components for each of the microcells (hereinafter also simply referred to as microcell material etc.) should be particularly limited if they can be arranged so as to relieve stress and / or thermal stress. The material of the minute cells arranged on the substrate may be the same material or the like, or two or more different materials or the like. In addition, in the plurality of electrodes constituting the battery, the material of the micro cell may be the same for each electrode, or may be different for each electrode.

  Further, the arrangement (pattern) of the microcells on the substrate is not particularly limited as long as it can be arranged so as to relieve stress and / or thermal stress. For example, a two-dimensional planar arrangement ( 1 may be an arrangement in the thickness direction (the Z-axis direction in FIG. 2), or a combination of these may be a three-dimensional three-dimensional arrangement. May be. Further, the arrangement (pattern) of the minute cells may or may not be uniform on the entire substrate. In addition, the arrangement (pattern) of the minute cells may be regular or irregular. Further, the regular arrangement does not have to be the entire base, and a regular part and an irregular part may be mixed on the base. Moreover, in the some electrode which comprises a battery, arrangement | positioning of the micro cell for every electrode may be the same, and may differ. If an attempt is made to construct a high-capacity, high-voltage, large-current battery, the electrodes constituting the battery also form tens to hundreds of tens of cell layers. In such a case, the temperature distribution and heat release (thermal conductivity) are different between the center of the multi-layered electrode and the vicinity of the outermost layer. This is because changing the arrangement (patterning) of the film may be optimal for relaxation of stress and thermal stress. The present invention is extremely excellent in that any patterning can be easily performed by forming a positive electrode layer, a negative electrode layer, and further an ion conductive layer using an inkjet method described later. In particular, the planar shape and size of the electrode layer on the printing screen of the computer software (printing software) connected to the inkjet printer, the composition, the material composition, the arrangement, etc. may be changed. In addition, when changing the composition or material of the component, if necessary, according to the change of the color (color) display on the print screen, if necessary, the ink of the ink jet printer (the ink in this specification is the positive electrode layer). , A negative electrode layer, and further, a raw material slurry obtained by adjusting the viscosity of the raw material used for forming the ion conductive layer with an appropriate solvent as necessary. Is called positive electrode ink, negative electrode layer forming material is called negative electrode ink, and ion conductive layer forming material is called electrolyte ink. (Refer to the examples described later.) The cartridge can be replaced and the design change can be handled very easily. be able to.

Regarding the length of the micro cell (the length L ₁ of the micro cell in the XY axis plane of FIG. 1) and the interval between the micro cells (the interval D ₁ between the micro cells in the XY axis plane of FIG. ₁ ). However, there is no particular limitation as long as it can be arranged so as to relieve stress and / or thermal stress. For example, it differs depending on the material, thickness, etc. of each micro cell, and when the micro cell is circular or irregular shape, the interval is not constant, and a plurality of micro cells having different planar shapes are randomly arranged. However, since the length of the micro cell is different for each planar shape and the interval is different for each micro cell, it should not be determined uniquely.

  The microcells only need to be able to relieve stress and / or thermal stress. For example, the microcells may be continuously arranged on the substrate without being spaced apart from each other. A plurality of cells may be arranged at intervals without being continuous (see FIGS. 1, 4, 6, 9 to 11), or a portion arranged at intervals from a portion arranged continuously. And may be mixed, and is not particularly limited. As an example in which a portion arranged continuously and a portion arranged at an interval are mixed, two adjacent minute cells are arranged continuously, and their cell aggregates are arranged at an interval. An example is given (see FIG. 8). In addition to the effects of the embodiments, the arrangements of FIGS. 8 and 9 can be applied in addition to the effects of the embodiments, even if minute cells having different resistance values, capacities, etc. are arranged consecutively without any interval even if no interval is provided. In addition, since the thermal stress can be relaxed, the respective microcells may be continuously arranged on the substrate without being spaced apart (the distance D). However, in the case where installation on a surface having a curvature as shown in FIG. 3 is required, it can be said that it is desirable to use an electrode in which a plurality of minute cells are arranged at intervals. On the other hand, when a battery with a large volumetric capacity is required, it is preferable to use electrodes in which microcells are continuously arranged without any gap, because the volumetric capacity can be increased by the absence of voids. It can be said.

  In the present invention, the arrangement of the two-dimensional surfaces of the microcells of the positive electrode layer and the negative electrode layer facing each other and the ion conductive layer sandwiched therebetween may be overlapped (same) (FIG. 2, 5, 7), may be shifted (different). This is the former from the viewpoint of improving the efficiency of the battery reaction.

  Moreover, in the electrode for secondary batteries of this invention, you may arrange | position a heat conductive layer in the gap | interval between the said microcells. In other words, a temperature change may be alleviated by disposing a material having good thermal conductivity in the gap between the microcells. Accordingly, a structure in which heat is quickly released (moved) through a material having a high thermal conductivity in the gap between the microcells can be obtained. Temperature change can be alleviated. In addition, this heat conductive layer does not need to be arrange | positioned in all the gap | intervals between microcells, and may be arrange | positioned in a part of gap | interval. The material having a high thermal conductivity (material having a good thermal conductivity) constituting the heat conductive layer includes a silicon material having no electron conductivity, and the composition ratio of the electrode layer forming material constituting the electrode layer. It may be changed. That is, since it is not necessary to prepare a new material and only the composition ratio is changed, the number of material parts can be reduced. In addition, when forming microcells by the ink jet method, it is excellent in that it is possible to respond sufficiently even by preparing inks for each composition component and changing the combination of inks used for printing by each microcell or heat conductive layer. ing.

  Moreover, in the electrode for secondary batteries of this invention, the kind and / or composition ratio of the electrode material which comprise an electrode layer may be changed, and you may arrange | position on a base | substrate. The electrode layer in this case includes a case where the electrode layer is finely divided into microcells and a case where it is not. This is because, for example, even if the resistance value, the capacitance, or the like is changed from the central portion toward the outer peripheral portion without providing a gap, the temperature distribution or the like can be made uniform (stress relaxation) in some cases.

  The target for changing the composition and type of the electrode material is not particularly limited, and examples thereof include an active material and / or conductive aid, but should not be limited to these.

  The arrangement (pattern) on the substrate may be a two-dimensional or one-dimensional arrangement in the plane direction (XY axis plane = direction perpendicular to the thickness direction), or may be multilayered on the substrate. In particular, the method of arrangement (pattern) is not particularly limited, such as when changing the arrangement (pattern) of the composition and type three-dimensionally, including the case of changing the arrangement only in the thickness direction. None (see FIGS. 10, 11 etc. described later).

  Further, in the secondary battery electrode of the present invention, each micro cell is arranged so that the resistance value of the micro cell formed by finely dividing the electrode layer changes from the central part to the outer peripheral part on the substrate. It may be characterized by that. In other words, the minute cells with different resistance values are arranged two-dimensionally or one-dimensionally in an inclined manner so that the temperature distribution is made uniform and the thermal stress due to the temperature change is alleviated. It may be. As a result, in the above-described operation and effect, it is possible to extend the life by making the temperature distribution uniform.

  The micro cell resistance value may be changed in a stepwise manner, or may be changed continuously or in a gradient (so to say, a functionally gradient material).

  The micro cell resistance value may be changed as long as it can be changed so as to relieve stress and / or thermal stress. For example, the resistance value of the micro cell is changed from the central portion toward the outer peripheral portion. The arrangement may be changed so as to be lowered in a two-dimensional or one-dimensional manner, stepwise, continuously, or in an inclined manner, but the arrangement is not limited at all.

  In the battery using the secondary battery electrode of the present invention, a heat exchanger may be provided outside the battery. Thereby, the heat generated inside the electrode during charging and discharging is efficiently taken out and cooled, and overheating inside the battery is prevented. Furthermore, in cold districts, it can be used for rapid heating to the operating temperature range of the battery using exhaust heat generated by the engine etc. at the start of the vehicle. Examples of the heat exchanger here include inorganic latent heat storage materials such as calcium chloride and calcium sulfate, paraffin-based latent heat storage materials, heat pipes, and the like. Here, the heat exchanger is defined as a part of the constituent member of the electrode, but needless to say, it may be a part of the constituent member of the battery or the assembled battery.

  In the secondary battery electrode of the present invention, electrode materials or microcells having different capacities and / or internal resistances are appropriately, preferably substantially evenly, more preferably evenly distributed on the substrate. It may be arranged. That is, among electrode materials or microcells having different capacities and / or internal resistances, moderately, preferably approximately evenly, more preferably equally, so that microcells of the same type are not localized and arranged. It can be said that they may be distributed and arranged. In other words, it can be said that by arranging minute cells having different resistance values (alternately), the current can be dispersed and the thermal stress due to the temperature change can be alleviated. As a result, the local flow of current can be relaxed, current uniformity and temperature distribution uniformity can be achieved, temperature rise can be prevented, and stress / thermal stress can be relaxed. In the case of a uniform internal resistance as in the prior art, if there is a part where current flows locally, the part generates heat. When heat is generated, the internal resistance of the part decreases. When the internal resistance decreases, the current easily flows to the relevant location, and the current further increases. In response, the amount of heat generation increases rapidly, so abnormalities such as short-circuiting due to heat melting of the electrode layer at the relevant location can occur. Will be invited. In the present invention, the problem due to unexpected chain heat generation can be solved by intentionally creating a region having a low capacitance or low internal resistance in the electrode layer.

  The method of arranging electrode materials or microcells having different capacities and / or internal resistances can be achieved by changing the composition and type of the electrode materials and microcells, and the present invention (same invention) is described in a multifaceted manner. It can be said that.

  Here, the number of different capacities and internal resistances may be two or more and is not particularly limited. In particular, in the inkjet method, three types of ink are prepared, and any combination of these can be combined to make hundreds to thousands of types. Therefore, the upper limit is not particularly limited.

  The arrangement (pattern; one-dimensional to three-dimensional arrangement) is not particularly limited as long as it can disperse current and can alleviate thermal stress due to temperature change. May be distributed substantially evenly so as not to be localized on the substrate. In two types of examples, for example, a structure in which electrode materials or microcells having different internal resistances are alternately arranged two-dimensionally, a so-called sea-island structure as shown in FIG. And a structure in which electrode materials or microcells of different types are sparsely arranged in a two-dimensional manner, in other words, a staggered pattern.

  In the secondary battery power supply of the present invention, it is desirable that the electrode layer is formed by applying a pattern electrode by an ink jet method. Further, it is desirable that the ratio of the conductive material constituting the electrode layer is changed continuously or in an inclined manner by the ink jet method. Further, it is desirable that the thickness of the electrode layer is in the range of 1 to 10 μm.

  In the pattern electrode coating by the inkjet method, cell characteristics can be controlled by the micro-cell size and the material mixing ratio, which are difficult to achieve especially by the conventional coating technique, and the ratio of the conductive material can be changed continuously and in an inclined manner. A vehicle battery that requires high output (30 kW), high voltage and large current (100 A × 300 V) can be significantly reduced in thickness and weight.

  Hereinafter, specific embodiments of the electrode for a secondary battery of the present invention will be described with reference to the drawings.

First Embodiment: Example of Configuration in which Rectangular Microcells are Two-dimensionally Tiled FIG. 1 shows a plurality of microcells arranged on a substrate as a specific embodiment of the secondary battery electrode of the present invention. 2 is a schematic plan view schematically showing a two-dimensional tile-like arrangement of microcells that can relieve stress during electrode formation and / or thermal stress due to temperature changes. FIG. 2 is a schematic side view schematically showing the state of a part of the electrode laminated structure of the secondary battery configured using the secondary battery electrode of FIG. FIG. 3 is an explanatory diagram schematically showing how the battery is bent and installed so that the secondary battery of FIG. 2 is placed in close contact with the surface having the curvature.

  The electrode 10 for a secondary battery shown in FIGS. 1 and 2 uses a two-dimensional current collecting layer (metal; thickness 5 μm) 11 as a substrate, and an X axis as a positive electrode layer on one surface of the current collecting layer 11. A rectangular (square) -shaped positive cell 12 (thickness: 5 μm) 12 is arranged in the Y-axis direction, and is similarly formed as a negative electrode layer on the other surface of the current collecting layer 11 in the X-axis and Y-axis directions. This is a bipolar electrode in which micro cells (thickness: 5 μm) 13 for a negative electrode having a shape are arranged. The electrode laminated structure of the secondary battery 20 shown in FIG. 2 is similarly rectangular on the positive electrode microcell 12 and / or the negative electrode microcell 13 on the bipolar electrode 10 in the X-axis and Y-axis directions. In this structure, a plurality of structures each formed by forming an ion conductive layer in which fine cells 14 (thickness: 5 μm) for ion conduction having a shape are formed are stacked in the Z-axis direction.

Moreover, at the installation of the micro cell 12 (also micro cells 13 and 14), between the micro cell 12 adjacent, spaced _{D 1} of the fine small cells 10% of the length _{L 1.} This is performed in both the X-axis and Y-axis directions of the current collecting layer 11. In other words, all the same square-shaped microcells are arranged on the rectangular surface formed by the XY axes of the substrate, and the microcells are arranged in both the X-axis and Y-axis directions respectively. In other words, it can be said that they are arranged in a grid pattern. In this embodiment, the arrangement (pattern) configuration is such that the micro cell length L ₁ = 10 mm and the gap distance D ₁ between micro cells is ₁ mm. In the present embodiment example, only one example of the effects of the present invention is shown, and the planar shape, length L ₁ , interval D _1, etc. of the microcells 12 to 14 should be limited to these. is not. In particular, the ion conductive layer sandwiched between the electrodes 10 may be arranged in the form of microcells as shown in FIG. 2, or a continuous body in which an electrolyte is impregnated in an existing electrolyte membrane or separator may be used. Needless to say.

  As shown in the present embodiment, the electrode is configured by arranging rectangular micro cells in a two-dimensional tile shape, so that even if the battery temperature varies widely from low temperature to high temperature, the current collecting layer, the positive electrode layer, Even when the thermal expansion coefficients of the negative electrode layer and the ion conductive layer are different, the thermal strain in the lateral direction of the electrode (X-axis and Y-axis surface direction) is eliminated, and several layers are applied on the current collecting layer using a conventional coater coating method. Compared with the case where the electrode layer is uniformly formed with a thickness of 10 mm or more, it is possible to greatly prevent the occurrence of cracks in the electrode or the distortion of the current collecting layer. Further, as already described with reference to FIG. 3, the microelectrodes are placed on the substrate with a space therebetween, whereby the entire electrode becomes flexible and can be bent with respect to the X axis or the Y axis. For this reason, even if it is the surface 33 which has a curvature in a certain direction, it can install along the surface 33 which has a curvature by bending the secondary battery 31 using this electrode. In the secondary battery of FIG. 3, it is desirable to use an existing multilayered laminate sheet rather than a metal sheet material so that not only the electrode but also the battery exterior material is flexible.

Second Embodiment: Other Configuration Example in which Rectangular Microcells are Two-dimensionally Tile-Installed FIG. 4 shows a plurality of microcells on a substrate as a specific embodiment of the secondary battery electrode of the present invention. FIG. 5 is a schematic plan view schematically showing another two-dimensional tile-like arrangement of microcells that can relieve stress at the time of electrode formation and / or thermal stress due to temperature changes, which is an example of the arrangement. FIG. 5 is a schematic side view schematically showing the state of a part of the electrode laminated structure of the secondary battery configured using the secondary battery electrode of FIG.

  The secondary battery electrode 40 shown in FIGS. 4 and 5 uses a two-dimensional current collecting layer (metal; thickness 5 μm) 41 as a base, and a Y-axis as a positive electrode layer on one surface of the current collecting layer 41. When arranging the rectangular positive electrode microcells (thickness 5 μm) 42 in the direction, they are alternately shifted and arranged on the other surface of the current collecting layer 41 as a negative electrode layer. This is a bipolar electrode formed by alternately shifting the rectangular negative cell for negative electrode (thickness 5 μm) 43 in the axial direction. The electrode laminated structure of the secondary battery 50 shown in FIG. 5 is similarly rectangular on the positive electrode microcell 42 and / or the negative electrode microcell 43 on the bipolar electrode 40 in the Y-axis direction. In disposing the ion conduction microcells 44 (thickness: 5 μm), a plurality of structures in which ion conductive layers arranged alternately are formed are stacked in the Z-axis direction.

Moreover, at the installation of the micro cell 42 (as well as micro-cells 43 and 44), between the micro cell 42 adjacent, spaced _{D 2} 10% of the fine small cell length _{L 2.} Further, the adjacent micro cell rows are arranged so as to be alternately shifted by the electrode shift amount C = the micro cell length L ₂ × 1.1 ÷ 2. In other words, the same square-shaped microcells are arranged on the rectangular surface formed by the XY axes of the substrate, and the microcells are arranged at equal intervals in both the X-axis and Y-axis directions. In addition, it can be said that the positions of the adjacent X-axis or Y-axis minute cell rows are changed (shifted) by a certain amount. In this embodiment, the arrangement (pattern) configuration is such that the micro cell length L ₂ = 5 mm, the gap distance D ₂ between micro cells = 0.5 mm, and the electrode shift amount C = 2.27 mm. In the present embodiment, only one example that exhibits the effects of the present invention is shown, and the planar shape, length L ₂ , distance D ₂ , electrode shift amount C, etc. of the microcells 42 to 44 are as follows. It should not be limited to any. In particular, the ion conductive layer sandwiched between the electrodes 40 may be arranged in the form of microcells as shown in FIG. 5, or a continuous body in which an electrolyte is impregnated in an existing electrolyte membrane or separator may be used. Needless to say.

  As shown in the present embodiment, the electrode is configured by arranging rectangular micro cells in a two-dimensional tile shape, so that the electrode layer is finely divided as in the first embodiment. Even when the battery temperature varies widely from low temperature to high temperature, and the thermal expansion coefficients of the current collection layer, positive electrode layer, negative electrode layer, and ion conduction layer are different, thermal strain in the lateral direction of the electrode (X-axis, Y-axis surface direction) It can be eliminated, and cracks in the electrodes and the like, or generation of distortion in the current collecting layer can be prevented. Moreover, it can be set as the structure which does not occur easily by buckling in a current collection layer part (by forming a micro cell alternately) with respect to the bending of a Y-axis direction.

Third Embodiment: Another Configuration Example in which Rectangular Microcells are Two-Dimensionally Tile-Installed FIG. 6 shows a plurality of microcells on a substrate as a specific embodiment of the secondary battery electrode of the present invention. FIG. 5 is a schematic plan view schematically showing still another arrangement of two-dimensional tiles of microcells that can relieve stress at the time of electrode formation and / or thermal stress due to temperature changes, which is an example of the arrangement. . FIG. 6 is a schematic side view schematically showing the state of a part of the electrode laminated structure of the secondary battery configured using the secondary battery electrode of FIG.

  The secondary battery electrode 60 shown in FIGS. 6 and 7 uses a two-dimensional current collecting layer (metal; thickness 5 μm) 61 as a base, and a Y-axis as a positive electrode layer on one surface of the current collecting layer 61. When arranging the rectangular positive cell 62 (thickness 5 μm) 62 in the direction, the X-axis and the Y-axis are alternately shifted, and similarly on the other surface of the current collecting layer 61 The bipolar electrode is formed by alternately shifting the X axis and the Y axis when the rectangular negative cell (thickness 5 μm) 63 having a rectangular shape is arranged in the Y axis direction as the negative electrode layer. The electrode laminated structure of the secondary battery 70 shown in FIG. 7 is similarly rectangular on the positive electrode microcell 62 and / or the negative electrode microcell 63 on the bipolar electrode 60 in the Y-axis direction. In arranging the ion conduction microcell 64 (thickness: 5 μm), a structure in which a plurality of structures in which an ion conductive layer is formed by alternately shifting the X axis and the Y axis is stacked in the Z axis direction. is there.

Further, in the installation of the micro cell 62 (the same applies to the micro cells 63 and 64), an interval D _{3 corresponding} to 10% of the micro cell length L ₃ is provided between the adjacent micro cells 62. Further, the adjacent micro cell rows have an arrangement configuration in which the electrode shift amount F = the micro cell length L ₃ × 1.1 ÷ 2 is alternately shifted. In other words, minute cells having the same rectangular shape are arranged on the rectangular surface formed by the XY axes of the substrate, and when arranging the minute cells, the minute cell rows are predetermined from the X axis or the Y axis. It can be said that the micro cells are arranged at equal intervals by alternately changing (shifting) the longitudinal direction of the micro cells by a predetermined angle (90 °) for each adjacent micro cell row. In the present embodiment example, the minute cell vertical length L ₃ = 8 mm, the minute cell lateral length S ₃ = 4 mm, the gap distance D ₃ between the vertical minute cells D = 0.8 mm, and the gap distance E ₃ = 0. The arrangement (pattern) configuration is 4 mm and the electrode shift amount F is 4.4 mm. In the present embodiment, only one example of the effects of the present invention is shown, and the planar shape, lengths L ₃ , S ₃ , distances D ₃ , E ₃ , and electrode shift of the microcells 62 to 64 are shown. The amount F and the like should not be limited to these. In particular, the ion conductive layer sandwiched between the electrodes 60 may be arranged in the form of microcells as shown in FIG. 7, or a continuous body in which an electrolyte is impregnated in an existing electrolyte membrane or separator may be used. Needless to say.

  As shown in the present embodiment, the electrode is configured by arranging rectangular micro cells in a two-dimensional tile shape, so that the electrode layer is finely divided as in the first embodiment. Even when the battery temperature varies widely from low temperature to high temperature, and the thermal expansion coefficients of the current collection layer, positive electrode layer, negative electrode layer, and ion conduction layer are different, thermal strain in the lateral direction of the electrode (X-axis, Y-axis surface direction) It can be eliminated, and cracks in the electrodes and the like, or generation of distortion in the current collecting layer can be prevented. Moreover, it can be set as the structure which does not occur more easily by buckling in a current collection layer part (because a minute cell is assembled | attached alternately) with respect to the bending of an X-axis and a Y-axis direction.

Fourth Embodiment: Other Configuration Example in which Triangular or Rhombus Microcells are Two-dimensionally Tile-Installed FIG. 8 shows a microcell on a substrate as a specific embodiment of the secondary battery electrode of the present invention. A schematic plan view schematically showing still another different arrangement of two-dimensional tiles of microcells capable of relieving stress during electrode formation and / or thermal stress due to temperature change. FIG.

The secondary battery electrode 80 shown in FIG. 8 uses a current collecting layer (metal; thickness 5 μm) 81 having a rectangular two-dimensional surface formed by XY axes as a base. On one side, as a positive electrode layer, (1) a positive cell microcell (thickness 5 μm) = a regular triangular shape, the same regular triangular microcell 82 is a current collecting layer 81 as a base. It is arranged on one side. In arranging the micro cells 82, the micro cells 82 are arranged in a so-called honeycomb shape. And between the honeycomb shape are arranged at a distance D _4. Each honeycomb shape is composed of six minute cells 82, and two adjacent minute cells 82 'are continuously arranged. And these continuum of two micro cells are also arranged at intervals D _4. (2) When viewed as positive microcells = rhombus shape, the same rhombus microcells 82 ′ are arranged on one side of the current collecting layer 81. In arranging the microcells 82 ′, the microcells 82 ′ are arranged in a honeycomb shape. Between each of the honeycomb shape are arranged at a distance D _4, 'constituted by micro cell 82' the respective honeycomb-shaped three micro cells 82 can be said that even while being spaced apart D _4. Similarly, on the other surface of the current collecting layer 81, a bipolar cell in which fine cells (thickness: 5 μm; not shown) for an equilateral triangle or rhombus are disposed as the negative electrode layer in the same manner as the positive electrode layer. Electrode. The secondary battery main body is formed, for example, on the positive electrode microcell 82 and / or the negative electrode microcell on the bipolar electrode 80 in the same manner as an equilateral triangle or rhombus ion conduction microcell (thickness). 5 μm; not shown) having a structure in which a plurality of structures in which an ion conductive layer in which the positive electrode layer and the negative electrode layer are arranged are formed are laminated in the thickness direction (Z-axis direction; not shown). Can do.

Further, in the installation of the microcell 82 or 82 ′ for the positive electrode (the same applies to the microcell for the negative electrode and the ion conduction), 10% of the microcell length L ₄ is placed between the adjacent microcells 82 or 82 ′. or it is obtained by the arrangement spaced D ₄ 5% of the L _{4 '.} In this embodiment, the arrangement (pattern) configuration is such that the minute cell length L ₄ = about 10 mm and the gap distance D ₄ between the minute cells is 1 mm. In the present embodiment, only one example that exhibits the effects of the present invention is shown, and the planar shape, length L ₄ , interval D _4, etc. of the microcells should not be limited to these. Absent.

As shown in the present embodiment, the same effects as those of the third embodiment can be achieved by adopting a configuration in which triangular or rhombus-shaped minute cells are two-dimensionally arranged in a tile shape. In particular, buckling in the current collecting layer portion (by forming minute cells alternately) with respect to bending in the X-axis and X-axis ± 120 ° directions can be made less likely to occur. Further, by arranging six among six micro cells constituting the individual honeycomb shape composed of small cells spaced all intervals D _4, 60 ° increments from the X-axis and the X axis, offset With respect to bending in all six directions, buckling in the current collecting layer portion (by forming minute cells alternately) can be made less likely to occur.

Fifth Embodiment: Another Configuration Example in which Cross-Shaped Microcells are Two-dimensionally Tiled As a specific embodiment of the secondary battery electrode of the present invention, FIG. 9 shows a plurality of microcells on a substrate. Schematic plan view schematically showing yet another different arrangement of two-dimensional tiles of microcells that can relieve stress during electrode formation and / or thermal stress due to temperature changes, which is an example of the arrangement. It is.

  An electrode 90 for a secondary battery shown in FIG. 9 uses a current collecting layer (metal; thickness 5 μm) 91 having a rectangular two-dimensional surface formed by an XY axis as a base. As a positive electrode layer on one side, when arranging the cross-shaped positive electrode microcells 92 in the Y-axis direction, they are alternately shifted, and similarly, on the other side of the current collecting layer 91, as a negative electrode layer , A bipolar electrode formed by alternately shifting the cross-shaped negative cell for negative electrode (thickness: 5 μm; not shown) in the Y-axis direction. Similarly, the secondary battery body is formed on the positive electrode microcell 92 and / or the negative electrode microcell on the bipolar electrode 90, similarly to the cross-shaped ion conduction microcell (thickness in the Y-axis direction). 5 μm (not shown) is a structure in which a plurality of structures each having an ion conductive layer formed by alternately shifting are stacked in the thickness direction (Z-axis direction; not shown).

Moreover, at the installation of the micro cell 92 for the positive electrode (negative electrode and micro cells for ionic conductivity as well), between micro cell 92 adjacent the interval D ₅ 10% of the fine small cell length L ₅ spaced It was. In other words, the same cross-shaped microcells are arranged at equal intervals on the rectangular surface formed by the XY axes of the substrate, and when the microcells are arranged, the microcell rows are arranged from the X axis to the Y axis. It can also be said that they are arranged at a predetermined angle (45 °) from the axis. In this embodiment, the arrangement (pattern) configuration is such that the micro cell length L ₅ = 15 mm, and the gap distance D ₅ between micro cells is 1.5 mm. In the present embodiment, only an example of the effects of the present invention is shown, and the planar shape, length L ₅ , interval D ₅ , electrode shift amount G, etc. of the microcell are not limited to these. Should not be done. In particular, the ion conductive layer sandwiched between the bipolar electrodes 90 may be arranged in the form of micro cells, and it goes without saying that a continuous body in which an electrolyte is impregnated in an existing electrolyte membrane or separator may be used.

  As shown in the present embodiment, the same effect as the third embodiment can be obtained by adopting a configuration in which rectangular micro cells are two-dimensionally installed in a tile shape. Moreover, it can be set as the structure by which buckling in a current collection layer part with respect to a bending (by forming a micro cell alternately) and it is hard to occur.

Sixth embodiment: configuration example in which two types of microcells having different resistance values are two-dimensionally arranged in a tile shape FIG. 10 shows a resistance value on a substrate as a specific embodiment of the electrode for a secondary battery of the present invention. FIG. 5 is a schematic plan view schematically showing a two-dimensional tile-like arrangement of minute cells, in which currents can be dispersed and thermal stress due to temperature changes can be reduced by arranging minute cells having different sizes.

  The secondary battery electrode 100 shown in FIG. 10 uses a current collecting layer (metal; thickness: 10 μm) 101 having a rectangular two-dimensional surface formed by XY axes as a substrate. When arranging positive hexagonal micro cells (thickness 5 μm) 102 in the X-axis and Y-axis directions as a positive electrode layer on one side, they are installed with an interval between adjacent micro cells. On the other side of the current collecting layer 101, as a negative electrode layer, a negative hexagonal micro cell (thickness: 5 μm; not shown) is arranged in the X-axis and Y-axis directions. It is a bipolar electrode formed with a gap in between. The electrode laminated structure of the secondary battery has a positive hexagonal ion conduction in the X-axis and Y-axis directions on the positive microcell 102 and / or the negative microcell on the bipolar electrode 100. When a micro cell (thickness: 5 μm; not shown) is disposed, a structure formed by forming an ion conductive layer with a space between adjacent micro cells is formed in the thickness direction (Z-axis direction; FIG. (Not shown).

Moreover, at the installation of the micro cell 102 for the positive electrode (negative electrode and micro cells for ionic conductivity as well), between micro cells 102 adjacent the interval D ₆ 15% of the fine small cell length L ₆ apart It was. Further, as shown in FIG. 10, the microcells 102a and 102b having different resistance values are alternately installed as the microcell 102 for the positive electrode (the opposing microcells for the negative electrode are also installed in the same manner. All of the microcells with the same resistance value were used.) In this embodiment, the arrangement is such that the micro cell length L ₆ = 10 mm and the space between the micro cells D ₆ = 1.5 mm. Further, the microcell 102a contains a large amount of conductive assistant and has a low resistance, and the microcell 102b has a small resistance value by adjusting the component composition of the microcell so that the content of the conductive assistant is small and the resistance is high. This is an example of forming a cell. In the present embodiment, only one example that exhibits the effects of the present invention is shown, and the planar shape, length L ₆ , interval D _6, etc. of the microcells are designed to distribute current and change temperature. If it can arrange | position so that the thermal stress by may be relieved, it should not be restrict | limited to these at all. Therefore, for example, if it is possible to disperse current by alternately arranging microcells having different resistance values and to relieve thermal stress due to temperature change, there is a space between adjacent microcells. There may be a case where a configuration that does not need to be taken. Similarly, in this embodiment, two types of microcells having different resistance values are used. However, the resistance values are different if they can be arranged so as to disperse current and relieve thermal stress due to temperature changes. Three or more types of microcells may be used, a plurality of microcells having different capacities instead of resistance values, or a plurality of microcells having different resistance values and capacities may be used. It is not limited. Furthermore, it goes without saying that the ion conductive layer sandwiched between the bipolar electrodes 100 may be arranged in microcells, or a continuous body in which an electrolyte is impregnated in an existing electrolyte membrane or separator may be used.

  With the configuration shown in the present embodiment, in the large current discharge, the current passes through the small cells 102a having a small resistance value that are uniformly distributed (distributed) on the plane of the current collecting layer, and the large current discharge. The heat generated by is dispersed on the electrode. Therefore, the local temperature rise on the electrode can be effectively suppressed by the structural electrode arrangement, and relaxation of thermal stress can be prevented.

  In addition, when the electrodes are finely divided (small cells), the battery temperature varies widely from low temperature to high temperature, and the thermal expansion coefficients of the current collection layer, positive electrode layer, negative electrode layer, and ion conduction layer are different. In addition, the thermal distortion in the lateral direction of the electrode (X-axis and Y-axis plane directions) is eliminated, and the electrode layer is uniformly formed with a thickness of several tens of mm or more on the entire surface of the current collecting layer by using a conventional coater coating method. Compared with the case where the structure is configured, it is possible to significantly prevent the occurrence of cracks or the like in the electrode or the distortion of the current collecting layer.

Seventh embodiment: configuration example in which minute cells having different resistance values are two-dimensionally installed in a slanted manner FIG. 11 shows subdivided resistance values as a specific embodiment of the secondary battery electrode of the present invention. By arranging different microcells in two dimensions or one-dimensionally in an inclined manner, the temperature distribution can be made uniform and thermal stress due to temperature changes can be mitigated. FIG.

  An electrode 110 for a secondary battery shown in FIG. 11 uses a current collecting layer (metal; thickness 10 μm) 111 having a rectangular two-dimensional surface formed with an XY axis as a base. On the one side, as a positive electrode layer, when arranging the positive microcells (thickness 5 μm) 102 having a circular shape in the X-axis and Y-axis directions, the microcells (thickness 5 μm) 102 are arranged with a space between adjacent microcells. On the other surface of the current collecting layer 111, as a negative electrode layer, a negative electrode microcell (thickness 5 μm; not shown) having a circular shape in the X-axis and Y-axis directions is arranged between adjacent microcells. It is a bipolar electrode that is installed at an interval. Further, the electrode laminated structure of the secondary battery is similarly used for ion conduction having a circular shape in the X-axis and Y-axis directions on the positive microcell 112 and / or the negative microcell on the bipolar electrode 110. When a micro cell (thickness: 5 μm; not shown) is arranged, a structure formed by forming an ion conductive layer with an interval between adjacent micro cells is formed in the thickness direction (Z-axis direction; not shown). 2) a plurality of layers.

Further, in the installation of the microcell 112 for positive electrode (the same applies to the microcell for negative electrode and ion conduction), an interval corresponding to 10% of the microcell length (diameter) L ₇ ( spaced minimum interval) _{D 7.} Further, as shown in FIG. 11, the positive electrode microcell 112 is installed at the central portion of the current collecting layer so that the resistance value becomes the largest, and the resistance increases as it goes around. It is arranged in a two-dimensional gradient so that the value is small. In this embodiment, the arrangement configuration is such that the micro cell length L ₇ = 10 mm and the gap distance D ₇ between micro cells is 1 mm. In the present embodiment, only one example of the effects of the present invention is shown, and the planar shape, length L ₇ , interval D _7, etc. of the microcells are intended to make the temperature distribution uniform, and As long as it can be arranged so as to relieve thermal stress due to temperature change, it should not be limited to these. For example, there may be a case where it is not necessary to provide a space between adjacent micro cells. Similarly, in the present embodiment example, a plurality of microcells having different resistance values are two-dimensionally arranged in a slanting manner so that the temperature distribution can be made uniform and thermal stress due to temperature change can be reduced. If there is, it may be arranged in a one-dimensionally slanted manner, or a plurality of minute cells having different resistance values in two-dimensional or one-dimensional steps may be arranged. There are no particular restrictions such as a plurality of micro cells having different capacities, or a plurality of micro cells having different resistance values and capacities. Furthermore, it goes without saying that the ion conductive layer sandwiched between the positive electrode layer and the negative electrode layer may be arranged in a micro cell, or a continuous body in which an electrolyte is impregnated in an existing electrolyte membrane or separator may be used.

  By adopting a configuration as shown in the present embodiment example, in the large current discharge, the current at the center is reduced, and it is possible to prevent the temperature rise at the center from abruptly rising due to heat generation of the battery.

  In particular, in polymer batteries, if a large temperature distribution is generated inside the electrode, the electrode resistance in the high temperature part further decreases, and there is a possibility that a current imbalance occurs in which a large amount of current flows into this part. By setting it as the said structure, temperature imbalance can be suppressed.

  Also, in this embodiment, by using the ink jet method, the conductive material ratio is changed by adjusting the ink application amount at the time of creating the electrode, and the resistance of the minute cells of the writing portion is changed in an inclined and continuous manner. I can go.

  In addition, because the electrodes are finely divided (small cells), the battery temperature varies widely from low temperature to high temperature, and the thermal expansion coefficients of the current collection layer, positive electrode layer, negative electrode layer, and ion conduction layer are different. In particular, the thermal distortion in the lateral direction of the electrode (X-axis, Y-axis plane direction) is eliminated, and a uniform electrode having a thickness of several tens of mm or more is formed on the entire surface of the current collecting layer by using a conventional coater coating method. Compared with the case where the layer is configured, cracks in the electrode and the like, or generation of distortion in the current collecting layer can be largely prevented.

  In the present embodiment, as shown in FIG. 11, the temperature management may be performed by arranging the heat exchanger 113 outside the two opposing sides of the current collecting layer 111. By setting it as such a structure, the heat | fever which generate | occur | produces with an electrode can be escaped efficiently outside. The heat exchanger 113 is not particularly limited. For example, if it is a power source mounted on a vehicle, an existing vehicle heat exchange system, for example, a car air conditioner system, exhaust heat of an engine, etc. The heat exchanger may be incorporated into a part of the heat exchange system by using the above, or a dedicated heat exchange system may be provided for the battery separately from these. In the heat exchanger, any battery can be used as long as it can function as a cooler from the viewpoint of suppressing an increase in the internal temperature of the battery during charging / discharging of the battery, as described above. In the case where the temperature is lower than the operating temperature, it is more desirable to be able to function as a heater as warm-up means. From this viewpoint, it can be said that it is desirable to use a heat storage material, a heat pipe, or the like. Needless to say, the installation of the heat exchanger according to the seventh embodiment can be applied to other embodiments.

Eighth embodiment: configuration example in which rectangular-shaped microcells are two-dimensionally tiled FIG. 12 shows a plurality of microcells arranged on a substrate as a specific embodiment of the secondary battery electrode of the present invention. In addition, a configuration example in which a material with good thermal conductivity is arranged in the gap between the microcells, and the two-dimensional tile-like arrangement of microcells that can quickly move heat and mitigate temperature changes. It is the plane schematic diagram which represented typically. FIG. 13 is a schematic side view schematically showing a state of a part of an electrode laminated structure of a secondary battery configured using the secondary battery electrode of FIGS. 13 and 12.

  The secondary battery electrode 120 shown in FIGS. 12 and 13 uses a two-dimensional current collecting layer (metal; thickness 5 μm) 121 as a base, and an X axis as a positive electrode layer on one surface of the current collecting layer 121. A rectangular (square) positive microcell (thickness 5 μm) 122 is arranged in the Y-axis direction, and the negative electrode layer is similarly rectangular on the other surface of the current collecting layer 121 in the X-axis and Y-axis directions. This is a bipolar electrode in which minute cells (thickness: 5 μm) 123 for a negative electrode having a shape are arranged. The electrode laminated structure of the secondary battery 130 shown in FIG. 13 is similarly rectangular on the positive electrode microcell 122 and / or the negative electrode microcell 123 on the bipolar electrode 120 in the X-axis and Y-axis directions. In this structure, a plurality of structures each formed by forming an ion conductive layer in which minute cells 124 (thickness 5 μm) for ion conduction are formed are stacked in the Z-axis direction.

Further, in the installation of the micro cell 122 (the same applies to the micro cells 123 and 124), an interval D _{8 corresponding} to 10% of the micro cell length L ₈ is provided between the adjacent micro cells 122. A good heat conductive layer 125 was provided here. This is performed in both the X-axis and Y-axis directions of the current collecting layer 121. Thereby, as shown in FIG. 13, the good heat conductive layer 125 is arrange | positioned as a continuous layer which connects between the current collection layers 121 adjacent. In this embodiment, the arrangement (pattern) configuration is such that the micro cell length A = 10 mm and the space between the micro cells D ₁ = 1 mm. In the present embodiment, only one example that exhibits the effects of the present invention is shown, and the planar shape, length L ₈ , interval D _8, etc. of the microcells 122 to 124 should be limited to these. is not. In particular, the ion conductive layer sandwiched between the electrodes 10 may be arranged in the form of microcells as shown in FIG. 13, or a continuous body in which an electrolyte is impregnated in an existing electrolyte membrane or separator may be used. Needless to say. Needless to say, the heat conductive layer 125 of the eighth embodiment can also be used in other embodiments having gaps between minute cells.

  Here, the heat conductive layer is a layer using a material having a higher thermal conductivity (a material having a higher thermal conductivity) than the electrode material constituting the micro cell of the electrode layer, and a part of the gap between the micro cells. Or it can arrange all. Further, as shown in FIG. 13, it can be formed so as to communicate between adjacent current collecting layers. In addition, when a heat conductive layer contains an electrode material, it can take also with 1 type of the microcell which comprises an electrode layer, and in this case, as demonstrated in 7th Embodiment, 2 types with different resistance values It can be said that this is an example in which minute cells are continuously used without being spaced apart. Here, examples of the material having good thermal conductivity include, but are not limited to, a silicon material.

  By adopting a configuration as shown in the present embodiment example, the battery temperature varies widely from low temperature to high temperature, and even when the thermal expansion coefficients of the current collecting layer, the positive electrode layer, the negative electrode layer, and the ion conductive layer are different, the heat conduction Layer 125 quickly transfers heat, relieves rapid temperature changes, eliminates thermal distortion in the electrode lateral direction (X-axis, Y-axis surface direction), and uses a conventional coater coating method to Compared with the case where the electrode layer is uniformly formed with a thickness of several tens of mm or more on the entire surface, cracks in the electrode or the like, or generation of distortion in the current collecting layer can be significantly prevented.

  In the method for producing an electrode for a secondary battery of the present invention, an electrode layer material (hereinafter also simply referred to as ink) is applied onto a substrate by patterning so as to relieve stress and / or thermal stress. It is characterized by forming. Thereby, even when the thermal expansion coefficients of the current collecting layer, the positive and negative electrode layers, and the ion conductive layer are different, the electrode layer can be formed by patterning so as to eliminate the thermal strain in the lateral direction of the electrode. As compared with the case where the electrode layer is uniformly formed by applying several tens of mm or more by applying with a conventional coater, the occurrence of cracks in the electrode or the like, or distortion of the current collecting layer can be largely prevented.

  As a specific embodiment of the method for manufacturing an electrode for a secondary battery of the present invention, as shown in FIGS. 1 to 13, (1) an electrode layer material is applied by patterning on a substrate, and an interval is formed on the substrate. A plurality of minute cells may be arranged to form the electrode layer. That is, in the present invention, the electrode layer material is applied by patterning on the substrate, and microcells are alternately arranged on the substrate so as to relieve the stress and / or thermal stress due to temperature changes during electrode formation. You may make it form.

  Further, as shown in FIGS. 12 and 13, (2) a material for an electrode layer may be applied by patterning on a substrate, and a heat conductive layer may be disposed in the gap between the microcells. That is, by the patterning application, a material having a higher thermal conductivity than the electrode material constituting the microcell is further arranged so that the heat is quickly transferred to the gap between the microcells and the temperature change is alleviated. May be.

  Further, as shown in FIGS. 10 and 11, (3) the composition and / or type of the electrode material constituting the electrode layer may be changed and arranged in the electrode layer on the substrate by patterning application. More specifically, as shown in FIG. 11, fine cells may be arranged so that the internal resistance value changes from the central portion to the outer peripheral portion on the substrate by patterning application. That is, by patterning application, the subdivided microcells with different resistance values are arranged in a two-dimensional or one-dimensional gradient so as to achieve uniform temperature distribution and alleviate thermal stress due to temperature changes. You may make it do. Alternatively, as shown in FIG. 12, by patterning, electrode materials or microcells having different capacities and / or internal resistances may be arranged on the substrate so as to be substantially evenly distributed. That is, by the patterning application, minute cells having different resistance values may be alternately arranged so as to distribute current and relieve thermal stress due to temperature change.

  In the manufacturing method of the electrode for secondary batteries of this invention, it is desirable to perform the said patterning application | coating by the printing application | coating method. Thereby, it is possible to achieve a complicated arrangement configuration of microcells as shown in FIGS. 1 to 13 which cannot be obtained by the conventional coater coating method by patterning coating. Thereby, in relieving stress and thermal stress, the electrode layer can be finely divided, or the composition component of the electrode layer can be changed continuously and in an inclined manner.

  The print coating method is not particularly limited, and examples thereof include an ink jet method. In particular, when an ink jet method is used, the ratio of the conductive material constituting the electrode layer is excellent in that it can be changed continuously or in an inclined manner, which is difficult to achieve with other methods. Thereby, it is possible to cope with a finer temperature change, and it is possible to further improve the uniformity of the temperature distribution.

  In addition, the inkjet method includes three methods, ie, a piezo element method, a thermal ink jet method, and a continuance method, and any of them can be adopted. From the viewpoint of thermal stability of the battery material, the piezo element method It is desirable to use

  Moreover, it is desirable to form the electrode layer so that the thickness after drying is in the range of 1 to 10 μm by the patterning application. As a result, it is necessary to stack several tens to hundreds of layers in a vehicle power supply that requires a high capacity and high voltage / term current, and even in such a case, the battery can be reduced in size and weight. It is. In particular, in the above-described ink jet method, a technique for ultra-miniaturizing ink jet droplets to about 1.8 pl has already been established, and theoretically about 10 μm by applying such an advanced technique. The electrode layer can be achieved. In order to achieve such an ultra-thin film by the existing coater coating method, it is necessary to increase the smoothness (flatness) of the substrate surface and coater surface to the limit, which is practically difficult to achieve and extremely expensive. .

  In the method for producing an electrode for a secondary battery of the present invention, as shown in FIG. 13, a heat exchanger may be installed on the outer periphery of the substrate and / or the electrode layer as necessary.

  Next, the secondary battery according to the present invention is characterized by using the above-described electrode for a secondary battery of the present invention. By using such a secondary battery electrode, the secondary battery according to the present invention can relieve stress at the time of electrode formation and / or thermal stress due to temperature change, and can extend the life of the battery. However, the present invention is not particularly limited and can be widely applied to various conventionally known secondary batteries.

  In the present invention, as described above, in the battery, in addition to the positive electrode layer and the negative electrode layer, the ion conductive layer (electrolyte layer) is also made into microcells in the same manner as the electrode, and the same arrangement configuration as the positive electrode layer and the negative electrode layer is used. It may be desirable to do so.

  The secondary battery of the present invention should not be limited at all except that the secondary battery electrode of the present invention described above is used, and other constituent elements are known in the art. Since the constituent requirements of the secondary battery can be used as appropriate, a brief description will be given here.

  The secondary battery according to the present invention is not particularly limited. For example, when distinguished by the structure of the battery, there are no particular restrictions such as a stacked (flat) battery or a wound (cylindrical) battery. It should not be applied, and can be applied to any conventionally known structure. Similarly, when distinguishing by the type of electrolyte of the secondary battery, it should not be particularly limited, and the liquid electrolyte type battery, polymer gel electrolyte type battery and solid polymer electrolyte (all solid electrolyte) type battery are not limited. It can be applied to both. These electrolytes can be used alone as these polymer gel electrolytes and solid polymer electrolytes (all solid electrolytes), or electrolytes, polymer gel electrolytes, solid polymer electrolytes (all solid electrolytes) can be used as separators (nonwoven fabrics). And the like can be used by being impregnated. Also, when viewed in terms of the electrical connection form (electrode structure) in the battery, it can be applied to both non-bipolar (internal parallel connection type) batteries and bipolar (internal series connection type) batteries. is there. A bipolar battery is preferable. A bipolar battery is a battery in which a plurality of unit batteries each having a positive electrode on one side and a negative electrode on the opposite side are stacked with a current collector foil interposed therebetween. In the case of stacking batteries that are not bipolar batteries, lead wires are taken from each of the positive electrode and the negative electrode and connected to the adjacent battery via the lead wires. In addition, when viewed from the electrode material of the secondary battery or metal ions that move between the electrodes, polymer lithium ion secondary battery, polymer sodium ion secondary battery, polymer nickel metal hydride secondary battery, etc. Instead, it can be applied to any conventionally known electrode material. A polymer lithium ion secondary battery is preferable. The polymer lithium ion secondary battery is suitable for a vehicle battery that requires a high cell voltage and a high output. Therefore, a high energy density and a high output density can be achieved, and an excellent polymer lithium ion secondary battery can be produced as a vehicle driving power source. Accordingly, in the following description, a polymer lithium ion secondary battery (a non-bipolar polymer lithium ion secondary battery and a bipolar polymer lithium ion secondary battery) using the electrode of the present invention will be described, but there is no limitation to these. Should not be done.

  That is, the polymer lithium ion secondary battery that is the subject of the present invention may be a polymer lithium ion secondary battery using the electrode of the present invention, and other constituent elements should not be limited at all. Therefore, a lithium ion secondary battery that is not bipolar will be described with reference to the drawings.

  FIG. 14 is a schematic cross-sectional view of a flat (stacked) polymer lithium ion secondary battery that is not a bipolar type. In the polymer lithium ion secondary battery 131 shown in FIG. 14, a positive electrode current collector is obtained by using a laminate film in which a polymer-metal composite is combined with a battery exterior material 133 and bonding the entire peripheral portion thereof by heat fusion. The negative electrode layer (positive electrode plate (positive electrode active material layer) 137 formed on both surfaces of the body 135, the electrolyte layer 139, and the negative electrode current collector 141 on both surfaces (one surface for the lowermost layer and the uppermost layer of the power generation element)) The power generation element in which the negative electrode plate on which the negative electrode active material layer) 143 is formed is accommodated and sealed. In addition, the positive electrode (terminal) lead 145 and the negative electrode (terminal) lead 147 that are electrically connected to the electrode plates (positive electrode plate and negative electrode plate) are connected to the positive electrode current collector 5 and the negative electrode current collector 141 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 exterior material 133.

  The polymer lithium ion secondary battery preferably has a flat (stacked) battery structure. In the case of a wound (cylindrical) battery structure, it may be difficult to improve the sealing performance at the location where the positive electrode and negative electrode lead terminals are taken out, and the high energy density mounted on the electric vehicle or hybrid electric vehicle, High-power density batteries may not be able to ensure long-term reliability of the sealing performance of the lead terminal extraction site, but by adopting a flat structure, long-term reliability is achieved by simple sealing technology such as thermocompression bonding. This is advantageous in terms of cost and workability.

  The electrode of the polymer lithium ion secondary battery uses a positive electrode that can occlude and release lithium ions and a negative electrode that can occlude and release lithium ions. A gel electrolyte or a solid electrolyte using molecules, or a solid electrolyte or a gel electrolyte including a separator can be used.

  In addition to the positive electrode current collector and the positive electrode active material layer, the positive electrode may be referred to as including the positive electrode terminal lead attached to the tip of the positive electrode current collector. The positive electrode plate refers to a reaction part including a positive electrode active material layer in the positive electrode current collector. In addition to the negative electrode current collector and the negative electrode active material layer, the negative electrode may be referred to as including a negative electrode terminal lead attached to the tip of the negative electrode current collector. A negative electrode plate shall mean the reaction part which comprises a negative electrode active material layer among negative electrode collectors. Therefore, the power generating element of the present invention is electrically connected to the negative electrode plate constituting the power generating element, the negative electrode terminal lead electrically connected to the negative electrode plate, the electrolyte layer, the positive electrode plate, and the positive electrode plate. It can be said that a positive electrode terminal lead is provided.

The positive electrode is preferably a positive electrode active material mainly composed of LiCoO ₂ , LiMn ₂ O ₄ , or LiNiO ₂ , but is not particularly limited. Although it is desirable to use carbon for a negative electrode, it is not specifically limited. Al foil and copper foil can be used for the positive electrode current collector and the negative electrode current collector, but are not particularly limited. The separator, gel-like or solid electrolyte used for the electrolyte layer is not particularly limited, and conventionally known ones can be used. These will be described in the bipolar battery described later.

  In the present invention, a power generation element in which a positive electrode plate, an electrolyte layer, and a negative electrode plate are laminated or wound is configured in the same manner as a conventional power generation element. For example, the positive electrode plate is formed by applying and drying a positive electrode active material containing a main material of the positive electrode active material and a polymer that absorbs and holds the organic electrolyte solution on both surfaces of the reaction portion of the positive electrode current collector, and then forming the positive electrode active material layer into the positive electrode current collector It is supported by the body. The negative electrode plate is formed by applying and drying a negative electrode active material containing a main material of the negative electrode active material and a polymer that absorbs and holds the organic electrolyte solution on both surfaces of a negative electrode current collector such as a Cu plate. It is supported by the body. The electrolyte layer is composed of a solid electrolyte or a gel electrolyte. The negative electrode active material layer on the upper side of the negative electrode plate is opposed to the positive electrode active material layer on the positive electrode plate above it via the electrolyte layer, and the negative electrode active material layer on the lower side of the negative electrode plate is connected to the positive electrode below it via the electrolyte layer In a state of being opposed to the positive electrode active material layer of the plate, these are laminated and integrated by thermal bonding to constitute a laminated electrode (power generation element). In addition, when the electrolyte layer is composed of a solid electrolyte, there are many cases in which a separator is not necessary, and the examples of the present invention also show examples in which no separator is used. Needless to say, it may be used. Moreover, what is comprised with the porous sheet | seat which consists of a polymer electrolyte sheet, a nonwoven fabric, etc. which absorb and hold | maintain an organic electrolyte solution etc. can be used for the said separator.

  As a metal (including an alloy) used for the electrode terminal lead, a metal selected from Cu and Fe can be used, but a metal such as Al and SUS (stainless steel) or an alloy material including these can be used as well. It is. From the viewpoint of suppressing an increase in resistance of the entire electrode terminal lead, it is desirable to use Cu. Furthermore, a surface coating layer may be formed on the electrode terminal lead in order to improve the adhesion of the exterior material to the polymer material. Ni can be most preferably used for the surface coating layer, but metal materials such as Ag and Au can also be used.

  In addition, a polymer-metal laminate film (also simply referred to as a polymer-metal composite laminate film) that is a battery exterior material is not particularly limited, and a metal film is disposed between the polymer films. However, a conventionally known one that is integrally laminated 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, a bipolar polymer lithium ion secondary battery will be described.

  A bipolar polymer lithium ion secondary battery has a structure in which a plurality of bipolar electrodes each having a positive electrode formed on one surface of a current collector and a negative electrode formed on the other surface are stacked in series with an electrolyte interposed therebetween. In the bipolar polymer lithium ion secondary battery, a battery having a higher voltage and higher capacity and output characteristics than a normal battery can be constructed. In addition, since it is a polymer battery that uses a gel or solid polymer as the electrolyte, there is no liquid leakage, so there is no problem of liquid junction, high reliability, and simple structure with excellent output characteristics. This is advantageous in that a polymer lithium ion secondary battery can be formed. Furthermore, bipolar polymer lithium ion secondary batteries using a lithium-transition metal composite oxide as the positive electrode active material are excellent in reactivity, cycle durability, and low cost. Therefore, these materials can be used as the positive electrode. The use is advantageous in that a battery having better output characteristics can be formed.

  Hereinafter, a bipolar polymer lithium ion secondary battery (hereinafter also simply referred to as a bipolar polymer battery), which is one of the preferred embodiments of the polymer battery of the present invention, will be described with reference to the drawings. It goes without saying that it should not be done.

  FIG. 15 is a schematic sectional view schematically showing the entire structure of the bipolar polymer battery. As shown in FIG. 15, in the bipolar polymer battery 151, a positive electrode (also referred to as a positive electrode active material layer) 155 is provided on one side of a current collector 153 composed of one or more sheets, and the other side is provided. A bipolar electrode 159 provided with a negative electrode (also referred to as a negative electrode active material layer) 157 of the present invention is opposed to electrode layers 155 and 157 of the bipolar electrode 159 which are adjacent to each other with the solid electrolyte layer 161 interposed therebetween. That is, in the bipolar polymer battery 151, a bipolar electrode (electrode layer) 159 having a positive electrode layer 1555 on one surface of the current collector 23 and a negative electrode layer 157 on the other surface is interposed via the electrolyte layer 161. The electrode laminate (bipolar battery main body) 163 has a structure in which a plurality of layers are laminated. Further, the uppermost layer and the lowermost layer electrodes 155a and 157a of the electrode laminate 163 in which a plurality of such bipolar electrodes 29 and the like are laminated may not have a bipolar electrode structure, and are necessary for the current collector 153 (or terminal plate). A structure in which electrode layers (positive electrode active material layer 155a and negative electrode active material layer 157a) only on one side are arranged may be employed. In the bipolar polymer battery 151, positive and negative electrode leads 165 and 167 are joined to current collectors 153 at both upper and lower ends, respectively. The number of stacked bipolar electrodes is adjusted according to the desired voltage. Further, in the bipolar polymer battery 151, a sufficient output can be ensured even if the thickness of the battery is made as thin as possible. Therefore, the number of lamination of the bipolar electrode 159 may be reduced. In the bipolar polymer battery 151 of the present invention, in order to prevent external impact and environmental degradation during use, the electrode laminate 1633 portion is sealed under reduced pressure in a battery exterior material (exterior package) 169, and electrode leads 165 are enclosed. , 167 is preferably taken out of the battery exterior material 169. From the viewpoint of weight reduction, a conventionally known battery exterior material such as a polymer-metal composite laminate film in which a metal (including an alloy) such as aluminum, stainless steel, nickel, or copper is covered with an insulator such as a polypropylene film is used. A structure in which the electrode laminate is housed and sealed under reduced pressure (sealing) by joining a part or all of its peripheral part by thermal fusion, and the electrode leads 165 and 167 are taken out of the battery exterior material 169. It is preferable to do this. The basic configuration of the bipolar polymer battery 151 can be said to be a configuration in which a plurality of stacked single battery layers (single cells) are connected in series.

  Hereinafter, the components of the bipolar polymer battery of the present invention will be mainly described.

  The constituent material of the positive electrode layer only needs to contain a positive electrode active material, and if necessary, a conductive assistant for increasing electronic conductivity, a binder, and an electrolyte supporting salt for increasing ionic conductivity ( Lithium salt), polymer electrolytes, additives, and the like, but when a polymer gel electrolyte or a liquid electrolyte is used for the electrolyte layer, a conventionally known binder that binds the positive electrode active material fine particles to each other, and increases the electron conductivity However, it does not have to include a host polymer, an electrolytic solution, or a lithium salt as a raw material of the polymer electrolyte. Even when a liquid electrolyte is used for the electrolyte layer, the positive electrode layer may not contain a host polymer, an electrolytic solution, a lithium salt, or the like as a raw material of the polymer electrolyte.

As the positive electrode active material, a composite oxide of lithium and transition metal (lithium-transition metal composite oxide) can be suitably used. Specifically, Li—Mn composite oxides such as LiMnO ₂ and LiMn ₂ O ₄ , Li—Co composite oxides such as LiCoO ₂ , Li—Cr such as Li ₂ Cr ₂ O ₇ and Li ₂ CrO _4. Li-Ni composite oxides such as LiNiO ₂ , Li-Fe composite oxides such as Li _x FeO _y and LiFeO _2, and Li-V composite oxides such as Li _x V _y O _z And selected from Li metal oxides such as those obtained by substituting a part of these transition metals with other elements (for example, LiNi _x Co _1-x O ₂ (0 <x <1), etc.) However, the present invention is not limited to these materials. These lithium-transition metal composite oxides are excellent in reactivity and cycle durability and are low-cost materials. Therefore, using these materials for the electrodes is advantageous in that a battery having excellent output characteristics can be formed. In addition, transition metal and lithium phosphate compounds and sulfate compounds such as LiFePO ₄ ; transition metal oxides and sulfides such as V ₂ O ₅ , MnO ₂ , TiS ₂ , MoS ₂ , and MoO ₃ ; PbO ₂ , AgO, NiOOH etc. are mentioned. Among the positive electrode active materials, a Li—Mn composite oxide is desirable. This is because (1) the profile can be tilted and (2) the reliability at the time of abnormality is improved by using the Li—Mn-based composite oxide. As a result, there is an advantage that the voltage of each single cell layer and the entire bipolar battery can be easily detected.

  Examples of the conductive aid include acetylene black, carbon black, graphite, various carbon fibers, and carbon nanotubes. 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.

  Among the above electrolytes, the polymer gel electrolyte is a solid polymer electrolyte having ion conductivity containing an electrolyte used in a lithium ion secondary battery that is not bipolar type. A polymer skeleton that does not have the same electrolyte solution is also included. Therefore, the polymer solid electrolyte among the electrolytes is a polymer solid electrolyte having ion conductivity.

Here, the electrolytic solution (electrolyte 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 , LiBOB (lithium bisoxide borate), LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, at least one kind selected from organic acid anion salts such as Li (C ₂ F ₅ SO ₂ ) ₂ N (lithium bis (perfluoroethylenesulfonylimide); also referred to as LiBETI) Cyclic carbonates such as propylene carbonate and ethylene carbonate; lithium carbonate (electrolyte salt); chain carbonates such as dimethyl carbonate, methyl ethyl carbonate, and diethyl carbonate; tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, Ethers such as 1,2-dimethoxyethane and 1,2-dibutoxyethane; lactones such as γ-butyrolactone; nitriles such as acetonitrile; esters such as methyl propionate; amides such as dimethylformamide; A material using a plasticizer (organic solvent) such as an aprotic solvent in which at least one selected from methyl formate or a mixture of two or more thereof can be used. However, it is not necessarily limited to these.

  Examples of the 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.

The ion as the conducting electrolyte supporting salts to improve the (lithium salt), for _{example, LiPF 6, LiBF 4, LiClO} 4, LiAsF 6, LiTaF 6, LiAlCl 4, Li 2 B 10 Cl ₁₀ and the like inorganic acid anion A salt, an organic acid anion salt such as Li (CF ₃ SO ₂ ) ₂ N, Li (C ₂ F ₅ SO ₂ ) ₂ N, or a mixture thereof can be used. However, it is not necessarily limited to these.

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

  In the present invention, in order to form the positive electrode layer, the positive electrode ink (the ink referred to in this specification means that the raw material used for forming the positive electrode layer, the negative electrode layer, and further the ion conductive layer is appropriately required. Accordingly, the raw material slurry obtained by adjusting the viscosity with an appropriate solvent is referred to as the positive electrode layer forming material is referred to as the positive electrode ink, the negative electrode layer forming material is referred to as the negative electrode ink, and the ion conductive layer forming material is referred to as the positive electrode layer forming material. This is called electrolyte ink (refer to the examples described later).

  In the present invention, it is desirable that the positive electrode layer, and the negative electrode layer and the electrolyte layer, which will be described later, are formed using an inkjet method. This is because a plurality of electrode layers (positive electrode layer, negative electrode layer) can be continuously formed on the current collector or the electrolyte layer. In particular, it is extremely suitable for forming electrode layers of different materials at intervals, and can be said to be a coating method with excellent production efficiency. This cannot be achieved by a coating method using a conventional coater, and can be realized for the first time by adopting a patterning coating method such as an inkjet method or a screen printing coating method found by the present inventors. It can be said that the scope of application is extremely wide.

  Further, in the present invention, the positive electrode layer, and further, a negative electrode layer, an electrolyte layer, an electronic conductive material layer, an insulating material, a sealing material, and the like, which will be described later, are formed by a coating method that prints by an inkjet method. desirable. As described above, an arbitrary pattern can be formed, and even a complicated pattern can be formed very finely without impairing the productivity. It can be said that it can be an extremely effective means for forming an electrode layer or the like in the case of stacking hundred cells. The application method for printing by the ink jet method has been described in detail in the examples described later, and description thereof is omitted here. However, the present invention should not be limited to the examples described later, and it is needless to say that the electrode layer and the like can be formed by appropriately using conventionally known ink jet technology.

  The negative electrode layer includes a negative electrode active material active material. In addition to this, a conductive auxiliary agent for increasing electronic conductivity, a binder, a polymer electrolyte (host polymer, electrolytic solution, etc.), a lithium salt for increasing ionic conductivity, an additive, etc. may be included. When a polymer gel electrolyte is used for the molecular electrolyte layer, it only needs to contain a conventionally known binder that binds the negative electrode active material fine particles to each other, a conductive auxiliary agent for increasing electronic conductivity, and the like. The host polymer, electrolyte solution, lithium salt and the like may not be contained. Even when a solution electrolyte is used for the electrolyte layer, the negative electrode layer may not contain a host polymer, an electrolytic solution, a lithium salt, or the like as a raw material of the polymer electrolyte. Since the contents other than the type of the negative electrode active material are basically the same as the contents described in the section of the positive electrode layer, description thereof is omitted here.

As the negative electrode active material, a negative electrode active material that is also used in a solution-type lithium ion battery can be used. Specifically, carbon, metal compounds, metal oxides, Li metal compounds, Li metal oxides (including lithium-transition metal composite oxides), boron-added carbon, graphite, and the like can be used. These may be used alone or in combination of two or more. Examples of the carbon include conventionally known carbon materials such as graphite carbon, hard carbon, and soft carbon. Examples of the metal compound include LiAl, LiZn, Li ₃ Bi, Li ₃ Cd, Li ₃ Sd, Li ₄ Si, Li _4.4 Pb, Li _4.4 Sn, and Li _0.17 C (LiC ₆ ). It is done. The metal _{oxides, SnO, SnO 2, GeO,} GeO 2, In 2 O, In 2 O 3, PbO, PbO 2, Pb 2 O 3, Pb 3 O 4, Ag 2 O, AgO, Ag 2 O ₃ , Sb ₂ O ₃ , Sb ₂ O ₄ , Sb ₂ O ₅ , SiO, ZnO, CoO, NiO, FeO and the like. Examples of the Li metal compound include Li ₃ FeN ₂ , Li _2.6 Co _0.4 N, Li _2.6 Cu _0.4 N, and the like. Examples of the Li metal oxide (lithium-transition metal composite oxide) include a lithium-titanium composite oxide represented by Li _x Ti _y O _z such as Li ₄ Ti ₅ O ₁₂ . Examples of the boron-added carbon include boron-added carbon and boron-added graphite. However, in this invention, it should not be restrict | limited to these but a conventionally well-known thing can be utilized suitably. The boron content in the boron-added carbon is preferably in the range of 0.1 to 10% by mass, but should not be limited to this. Preferably, the material is selected from a crystalline carbon material and an amorphous carbon material. By using these, the profile can be tilted, and the voltage of each single cell layer and the entire bipolar becomes easy to detect. The crystalline carbon material here refers to a graphite-based carbon material, and includes the above-described graphite carbon and the like. The non-crystalline carbon material refers to a hard carbon-based carbon material, and includes the hard carbon and the like.

  The current collector is not particularly limited, and a conventionally known one can be used. For example, aluminum foil, stainless steel (SUS) foil, titanium foil, nickel-aluminum clad material, copper-aluminum clad material, SUS-aluminum clad material, or a plating 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. Moreover, you may use the electrical power collector which bonded 2 or more metal foil depending on the case. 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.

  Each thickness of the positive electrode current collector and the negative electrode current collector in the composite current collector may be as usual, and both current collectors are, for example, about 1 to 100 μm. The thickness of the current collector (including the composite current collector) is preferably about 1 to 100 μm from the viewpoint of thinning the battery.

  The electrolyte layer can be applied to any of (a) a polymer gel electrolyte, (b) a polymer solid electrolyte, or (c) a separator (including a nonwoven fabric separator) impregnated with these polymer electrolytes or electrolytes. Is. Further, in the present invention, a liquid electrolyte obtained by impregnating a separator with an electrolytic solution by sealing each electrolyte layer using an insulating layer sealing material can also be used.

(A) Polymer gel electrolyte The polymer gel electrolyte is not particularly limited, and those used in conventional gel electrolyte layers can be appropriately used. Here, the gel electrolyte refers to one in which an electrolytic solution is held in a polymer matrix. In the present invention, the difference between an all solid polymer electrolyte (also simply referred to as a polymer solid electrolyte) and a gel electrolyte is as follows.

  A gel electrolyte is an all-solid polymer electrolyte such as polyethylene oxide (PEO) containing an electrolytic solution used in a normal lithium ion battery.

  A gel electrolyte is a polymer electrolyte such as polyvinylidene fluoride (PVDF) in which a polymer skeleton having no lithium ion conductivity is held.

  -The ratio of the polymer constituting the gel electrolyte (also referred to as host polymer or polymer matrix) and the electrolytic solution is wide. When 100% by mass of the polymer is an all solid polymer electrolyte and 100% by mass of the electrolytic solution is a liquid electrolyte, an intermediate thereof Are all gel electrolytes.

  A host polymer of the gel electrolyte is not particularly limited, and a conventionally known one can be used. Preferably, polyethylene oxide (PEO), polypropylene oxide (PPO), polyethylene glycol (PEG ), Polyacrylonitrile (PAN), polyvinylidene fluoride-hexafluoropropylene (PVdF-HFP), poly (methyl methacrylate) (PMMA) and copolymers thereof are preferable, and the solvents include ethylene carbonate (EC), propylene carbonate (PC), γ-butyrolactone (GBL), dimethyl carbonate (DMC), diethyl carbonate (DEC), and mixtures thereof are preferred.

The electrolyte solution (electrolyte salt and plasticizer) of the gel electrolyte is not particularly limited, and conventionally known ones can be used. Specifically, as long as usually used in a lithium ion battery, for _{example, LiPF 6, LiBF 4, LiClO} 4, LiAsF 6, LiTaF 6, LiAlCl 4, Li 2 B 10 Cl ₁₀ and the like inorganic acid anion At least one lithium salt (electrolyte salt) selected from organic acid anion salts such as a salt, LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, Li (C ₂ F ₅ SO ₂ ) ₂ N ), Cyclic carbonates such as propylene carbonate and ethylene carbonate; chain carbonates such as dimethyl carbonate, methyl ethyl carbonate, and diethyl carbonate; tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane , 1,2-dibutoxyethane, etc. Lactones such as γ-butyrolactone; nitriles such as acetonitrile; esters such as methyl propionate; amides such as dimethylformamide; at least one or more selected from methyl acetate and methyl formate A mixed organic solvent (plasticizer) such as an aprotic solvent can be used. However, it is not necessarily limited to these.

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

  In the present invention, the amount of the electrolyte contained in the gel electrolyte may be substantially uniform inside the gel electrolyte, or may be decreased in an inclined manner from the central portion toward the outer peripheral portion. . The former is preferable because reactivity can be obtained in a wider range, and the latter is preferable in that the sealing property of the all solid polymer electrolyte portion in the outer peripheral portion with respect to the electrolytic solution can be improved. When decreasing gradually from the central part toward the outer peripheral part, polyethylene oxide (PEO), polypropylene oxide (PPO) and copolymers thereof having lithium ion conductivity are used as the host polymer. It is desirable.

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

(C) Separator (including non-woven fabric separator) impregnated with the polymer electrolyte or electrolytic solution (electrolyte salt and plasticizer)
As the electrolyte that can be impregnated in the separator, the same electrolyte (electrolyte salt and plasticizer) solution as described in (a) and (b) or (a) described above can be used. The description in is omitted.

  The separator is not particularly limited, and a conventionally known separator can be used. For example, a porous sheet made of a polymer that absorbs and holds the electrolyte (for example, a polyolefin microporous separator). Etc.) 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 polymer material include polyethylene (PE), polypropylene (PP), a laminate having a three-layer structure of PP / PE / PP, and polyimide.

  The thickness of the separator cannot be unambiguously defined because it varies depending on the intended use. However, in the case of a secondary battery for driving a motor such as an electric vehicle (EV) or a hybrid electric vehicle (HEV), a single layer is used. Or it is desirable that it is 4-60 micrometers in a multilayer. The mechanical strength in the thickness direction is desirable because the thickness of the separator is within such a range, and it is desirable to narrow the gap between the electrodes for high output and prevention of short-circuiting caused by fine particles entering the separator. And there is an effect of ensuring high output performance. 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.

  The fine pore diameter of the separator is desirably 1 μm or less (usually a pore diameter of about several tens of nm). Since the average diameter of the micropores in the separator is within the above range, the “shutdown phenomenon” that the separator melts due to heat and the micropores close quickly occurs, resulting in higher reliability during abnormalities, resulting in heat resistance. Has the effect of improving. In other words, when the battery temperature rises due to overcharging (in an abnormal state), the “shutdown phenomenon” that the separator melts and closes the micropores occurs quickly, so that the positive electrode (+) of the battery (electrode) Li ions cannot pass through to the negative electrode (−) side, and no further charge is possible. As a result, overcharging cannot be performed and overcharging is eliminated. As a result, the heat resistance (safety) of the battery is improved, and it is possible to prevent gas from being released and the heat fusion part (seal part) of the battery exterior material from being opened. 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 separator preferably has a porosity of 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.

  The amount of electrolyte impregnated into the separator may be impregnated up to the holding capacity range of the separator, but may be impregnated beyond the holding capacity range. This can be impregnated as long as it can be retained in the electrolyte layer because a seal portion is provided in the electrolyte and the electrolyte solution can be prevented from exuding from the electrolyte layer.

  The nonwoven fabric separator used for holding the electrolyte is not particularly limited, and can be manufactured by entwining the fibers into a sheet. Moreover, the spun bond etc. which are obtained by fusing fibers by heating can also be used. In other words, it may be in the form of a sheet formed by arranging fibers in a web (thin cotton) shape or mat shape by an appropriate method, and joining them using an appropriate adhesive or the fusing force of the fibers themselves. The adhesive is not particularly limited as long as it has sufficient heat resistance at the temperature during manufacture and use, and is stable without any reactivity or solubility with respect to the gel electrolyte. There are no known ones. The fiber used is not particularly limited, and for example, conventionally known fibers such as cotton, rayon, acetate, nylon, polyester, polypropylene, polyethylene and other polyolefins, polyimide, and aramid can be used. Depending on (such as mechanical strength required for the electrolyte layer), 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, and the ionic conductivity and the like in the electrolyte layer may be impaired.

  The porosity of the nonwoven fabric separator is preferably 50 to 90%. If the porosity is less than 50%, the electrolyte retention deteriorates, and if it exceeds 90%, the strength is insufficient. Furthermore, the thickness of the nonwoven fabric separator may be the same as that of the electrolyte layer, preferably 5 to 200 μm, particularly preferably 10 to 100 μm. When the thickness is less than 5 μm, the electrolyte retention deteriorates, and when it exceeds 200 μm, the resistance increases.

  In addition, you may use together the electrolyte layer of said (1)-(3) in one battery.

  In addition, the polymer electrolyte may be contained 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, or different polymer electrolytes may be used depending on the layer.

  By the way, a host polymer for a polymer 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 using a positive electrode agent having a high oxidation-reduction potential that is generally used in a solution-type lithium ion battery, the capacity of the negative electrode is preferably smaller than the capacity of the positive electrode facing through the polymer electrolyte layer. . If the capacity of the negative electrode is less than the capacity of the opposing positive electrode, it is possible to prevent the positive electrode potential from rising excessively at the end of charging. In addition, the capacity | capacitance of a positive electrode and a negative electrode can be calculated | required from manufacturing conditions as theoretical capacity | capacitance at the time of manufacturing a positive electrode and a negative electrode. You may measure the capacity | capacitance of a finished product directly with a measuring device.

  However, if the capacity of the negative electrode is smaller than the capacity of the opposing positive electrode, the negative electrode potential will be too low 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 bipolar polymer battery, it is preferable to make it as thin as possible as long as the function as an electrolyte can be secured. The thickness of a general electrolyte layer is 5 to 200 μm, preferably about 5 to 20 μm.

  The insulating sheet material (insulating layer) is formed around each electrode for the purpose of preventing current collectors adjacent in the battery from contacting each other and short-circuiting due to slight unevenness at the end of the laminated electrode. In the present invention, since the outside of the battery current collector is covered (sealed) with the resin group having the function of the insulating layer, it is not necessary to form an insulating layer. In the bipolar battery of the invention, an embodiment in which an insulating layer is provided around the electrode is not excluded.

  Since many functions required for the insulating layer are provided by the resin group of the present invention, as a material used for the insulating layer, in addition to insulating properties, heat resistance under battery operating temperature, resistance to electrolytic solution, etc. For example, epoxy resin, rubber, polyethylene, polypropylene, polyimide, etc. can be used. From the viewpoint of corrosion resistance, chemical resistance, ease of production (film formation), economy, etc., epoxy Resins are preferred.

The positive electrode and the negative electrode tab may be used as necessary. In other words, depending on the laminated (or wound) structure of the bipolar battery, the outermost current collector may be directly taken out as an electrode terminal, and in this case, the positive electrode and the negative electrode terminal (tab) may not be used.

  When using a positive electrode and a negative electrode tab, 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 low mechanical strength. For this reason, it is desirable to have sufficient strength to sandwich and support them from both sides. Furthermore, it can be said that the thickness of the positive electrode and the negative electrode tab is usually preferably about 0.1 to 2 mm from the viewpoint of suppressing the internal resistance at the electrode tab.

  As the material of the positive electrode and the negative electrode tab, a material used in a normal lithium ion secondary battery that is not a bipolar type can be used. For example, aluminum, copper, titanium, nickel, stainless steel (SUS), and alloys thereof can be used.

  The materials of the positive electrode tab and the negative electrode tab may be the same material or different materials. Further, the positive electrode and the negative electrode tab may be formed by stacking different materials.

As for the positive electrode and the negative electrode lead, known leads used in ordinary polymer lithium ion batteries which are not the bipolar type described above 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.

  As the battery exterior material (battery case) 20, in order to prevent external impact during use and environmental degradation, the battery stack or the entire battery winding body as the battery body is accommodated in the battery exterior material or battery case. It is desirable to do. From the viewpoint of weight reduction, a polymer-metal composite laminate film 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) ( For example, by using a conventionally known battery exterior material such as a polypropylene-aluminum composite laminate film (also simply referred to as an aluminum laminate film), a part or all of the peripheral part thereof is bonded by heat-sealing, whereby a battery laminate is obtained. It is preferable that the container 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.

  Next, as a use of the polymer battery of the present invention, for example, as a large-capacity power source such as an electric vehicle (EV), a hybrid electric vehicle (HEV), a fuel cell vehicle and a hybrid fuel cell vehicle, a high energy density and a high output density are used. Can be suitably used for a vehicle driving power source (including an auxiliary power source). In this case, it is desirable that the assembled battery is constructed by connecting a plurality of polymer batteries of the present invention. That is, using at least one of the polymer batteries of the present invention, particularly bipolar polymer lithium ion secondary batteries, using at least one connection method of parallel connection, series connection, parallel-series connection and series-parallel connection. By configuring the assembled battery, a battery module with a high capacity and a high output can be formed. Therefore, it becomes possible to respond to the demand for battery capacity and output for each purpose of use at a relatively low cost.

  Specifically, for example, N polymer batteries are connected in parallel, and N polymer batteries connected in parallel are further connected in series in a metal or resin battery case to form a battery pack. . At this time, the number of series / parallel connections of the polymer battery is determined according to the purpose of use. For example, as a large-capacity power source such as EV, HEV, fuel cell vehicle, and hybrid fuel cell vehicle, it can be applied to a driving power source (including an auxiliary power source) for a vehicle that requires high energy density and high output density. Good. Moreover, what is necessary is just to electrically connect the positive electrode terminal and negative electrode terminal for assembled batteries, and the electrode lead of each polymer battery using a lead wire. Moreover, what is necessary is just to electrically connect using suitable connection members, such as a spacer and a bus bar, when connecting polymer batteries in series / parallel. However, the assembled battery of the present invention should not be limited to those described here, and conventionally known ones can be appropriately employed.

  In the present invention, a vehicle equipped with the polymer battery and / or the assembled battery as a driving power source (including an auxiliary power source) can be provided. The polymer battery and / or the assembled battery of the present invention have various characteristics as described above, and are particularly compact batteries. For this reason, it is suitable as a driving power source (including an auxiliary power source) for vehicles that are particularly demanding regarding energy density and output density, such as electric vehicles, hybrid electric vehicles, fuel cell vehicles, and hybrid fuel cell vehicles. EVs, HEVs, fuel cell vehicles and hybrid fuel cell vehicles with excellent fuel efficiency and driving performance can be provided. For example, it is convenient to install an assembled battery as a driving power source under the seat at the center of the body of an EV, HEV, fuel cell vehicle, or hybrid fuel cell vehicle because the company space and trunk room can be widened. However, the present invention is not limited to these, and the assembled battery or battery can be installed under the floor of the vehicle, in a trunk room, an engine room, a roof, a hood, or the like. In the present invention, not only the assembled battery but also a polymer battery may be mounted depending on the use application, or these assembled battery and polymer battery may be mounted in combination. Further, as the vehicle on which the polymer battery and / or the assembled battery of the present invention can be mounted as a driving power source, the above-described EV, HEV, fuel cell vehicle, and hybrid fuel cell vehicle are preferable, but are not limited thereto. is not.

Hereinafter, the present invention will be described in more detail by way of examples. In the following examples, the following materials were used as the polymer electrolyte raw material, lithium salt, positive electrode active material, and negative electrode active material unless otherwise specified.
Polymer electrolyte raw material: Macromer of ethylene oxide and propylene oxide Lithium salt: LiN (SO ₂ C ₂ F ₅ ) ₂ (hereinafter abbreviated as “BETI”)
Positive electrode active material: spinel type LiMn ₂ O ₄ (average particle size: 0.6 μm)
Negative electrode active material: pulverized graphite (average particle size: 0.7 μm)
Photopolymerization initiator: benzyl dimethyl ketal The polymer electrolyte raw material was synthesized according to the method described in JP-A No. 2002-110239. Moreover, preparation, printing, and battery assembly of the negative electrode ink, the positive electrode ink, and the electrolyte ink were performed in a dry atmosphere with a dew point of −30 ° C. or less.

(Example 1)
<Preparation of negative electrode ink>
A negative electrode active material (9% by mass), a polymer electrolyte raw material (4% by mass), a lithium salt (2% by mass), and a photopolymerization initiator (0.1% by mass with respect to the polymer electrolyte raw material) were prepared, Acetonitrile (85 mass%) was added to these as a solvent. This was sufficiently stirred to prepare a slurry as negative electrode ink. The viscosity of this ink was about 3 cP.

<Preparation of positive electrode ink>
Positive electrode active material (7% by mass), acetylene black (2% by mass) as a conductive material, polymer electrolyte material (4% by mass), lithium salt (2% by mass), and photopolymerization initiator (based on polymer electrolyte material) 0.1 wt%) was prepared, and acetonitrile (85 wt%) was added as a solvent thereto. This was sufficiently stirred to prepare a slurry as a positive electrode ink. The viscosity of this ink was about 3 cP.

<Preparation of electrolyte ink>
A polymer electrolyte raw material (15% by mass), a lithium salt (8% by mass), and a photopolymerization initiator (0.1% by mass with respect to the polymer electrolyte raw material) were prepared, and acetonitrile (77% by mass) was used as a solvent. ) Was added. This was sufficiently stirred to prepare a slurry as an electrolyte ink. The viscosity of this ink was 2 cP.

<Production of battery>
A battery was prepared according to the following procedure using the prepared ink and a commercially available ink jet printer. When the above ink is used, there is a problem that acetonitrile as a solvent dissolves plastic parts in the ink introduction portion of the ink jet printer. Therefore, the parts in the ink introduction part were replaced with metal parts, and ink was directly supplied from the ink reservoir to the metal parts. Further, since there was a concern that the viscosity of the ink was low and the active material was precipitated, the ink reservoir was always stirred using a rotary blade.

The inkjet printer was controlled by a commercially available computer and software. When preparing the negative electrode layer, the polymer electrolyte membrane (ion conductive layer), and the positive electrode layer, the prepared negative electrode ink, electrolyte ink, and positive electrode ink were used. The negative electrode layer, the polymer electrolyte membrane (ion conductive layer), and the positive electrode layer had a pattern created on a computer (in this example, a pattern in which rectangular microcells shown in FIG. 1 were two-dimensionally arranged in a tile shape. .) Was printed using an inkjet printer. In addition, since it was difficult to supply the metal foil used as the current collecting layer directly to the printer, the metal foil was pasted on the A4 quality paper, supplied to the printer, and printed (also in the following examples) In this embodiment, the current collecting layer and further the polymer electrolyte membrane (ion conductive layer) are attached to the A4 quality paper, and the current collecting layer and polymer electrolyte membrane are supplied to the printer and printed. And the same). Further, in this example, the negative electrode layer, the polymer electrolyte membrane (ion conductive layer), and the positive electrode layer were printed so that the thickness (after drying) was 5 μm, and as shown in FIG. The arrangement (pattern) configuration was such that the length L ₁ of each of the negative electrode and ion conduction microcells was 10 mm, and the gap distance D ₁ between the microcells was ₁ mm. The thickness of the current collecting layer was 5 μm, and the size of the current collecting layer was the same as the size of the A4-size fine paper.

  A negative electrode ink was introduced into the modified inkjet printer, and a pattern created on a computer was printed on a stainless steel foil as a current collecting layer. After printing, in order to dry the solvent, drying was performed in a vacuum oven at 60 ° C. for 2 hours. After drying, in order to polymerize the polymer electrolyte raw material, ultraviolet rays were irradiated for 20 minutes in vacuum to obtain a laminate in which the negative electrode layer was laminated on the current collecting layer.

  The electrolyte ink was introduced into the modified inkjet printer, and the electrolyte ink was printed on the negative electrode layer so as to have the same pattern as the negative electrode layer. The formed polymer electrolyte membrane (ion conductive layer) was uniformly formed with no unevenness. After printing, in order to dry the solvent, drying was performed in a vacuum oven at 60 ° C. for 2 hours. After drying, in order to polymerize the polymer electrolyte raw material, ultraviolet rays were irradiated in vacuum for 20 minutes to obtain a laminate of a current collecting layer, a negative electrode layer, and a polymer electrolyte membrane (ion conductive layer).

  Similarly, the positive electrode ink was printed on the polymer electrolyte membrane (ion conductive layer) so that the formed positive electrode layer had the same pattern as the negative electrode layer. After printing, in order to dry the solvent, drying was performed in a vacuum oven at 60 ° C. for 2 hours. After drying, in order to polymerize the polymer electrolyte raw material, ultraviolet rays were irradiated for 20 minutes in a vacuum to obtain a laminate of a current collector, a negative electrode layer, a polymer electrolyte membrane (ion conductive layer), and a positive electrode layer.

  This laminate was sandwiched between stainless foils as a current collecting layer. Finally, the battery was sealed and molded with an aluminum laminate so that only the positive and negative electrode leads came out of the battery. Specifically, the aluminum laminate material here is a resin film that physically protects the metal thin film of aluminum foil and the metal thin film of polyethylene terephthalate so that the exchange of gases such as water vapor and oxygen is not performed inside and outside the container. Also, it refers to a laminate sheet in which ionomer heat-fusible resin films are stacked to form a multilayer.

<Battery evaluation>
The manufactured battery was subjected to constant current / constant voltage charging at ²⁰ μA / cm ^{2 at} an upper limit voltage of 4.2 V, and then constant current discharge at ²⁰ μA / cm ² was performed at a lower limit voltage of 2.5 V. As a result of the charge / discharge evaluation, a charge / discharge plateau was observed in the vicinity of an average voltage of about 3.8 V, and it was confirmed that the produced battery was functioning. In addition, although a cooling cycle was applied, no cracks were generated.

(Example 2)
<Production of battery>
In the preparation of the negative electrode ink, the positive electrode ink, and the electrolyte ink, the amount of the solvent was reduced to half that of Example 1, and an ink having a high viscosity was obtained. Since the viscosity of the ink is high, when the printing is performed as it is, streaks and blurring occur in the printing. Therefore, a heater was attached to the ink reservoir of the inkjet printer to warm the ink. As a result, the ink viscosity was in an appropriate state, and beautiful printing was possible. Others were the same as in Example 1, and printing, drying, polymerization, assembly, and evaluation were performed.

<Evaluation>
The charge / discharge characteristics were evaluated in the same manner as in Example 1. As a result of the charge / discharge evaluation, a charge / discharge plateau was observed in the vicinity of an average voltage of about 3.8 V, and it was confirmed that the produced battery was functioning.

(Example 3)
<Preparation of polymer electrolyte membrane (ion conductive layer)>
A polymer electrolyte raw material (53% by mass), a lithium salt (26% by mass), and a photopolymerization initiator (0.1% by mass with respect to the polymer electrolyte raw material) were prepared, and acetonitrile (21% by mass) was used as a solvent. ) Was added. This solution was soaked into a polyester resin nonwoven fabric separator having a porosity of about 50%. The nonwoven fabric separator soaked with the solution was dried in a vacuum oven at 60 ° C. for 2 hours. Furthermore, the dried nonwoven fabric separator was photopolymerized by irradiating with ultraviolet rays for 20 minutes in a vacuum to obtain a polymer electrolyte membrane (ion conductive layer). The thickness (after drying) of the polymer electrolyte membrane (ion conductive layer) was 5 μm. The size of the polymer electrolyte membrane (ion conductive layer) was the same as the size of the A4 size fine paper.

<Production of battery>
Using this polymer electrolyte membrane (ion conductive layer) as a substrate, a negative electrode layer was produced on the polymer electrolyte membrane (ion conductive layer) in the same manner as in Example 1. Further, a positive electrode layer was produced on the opposite surface of the negative electrode layer by the same method as in Example 1. In this example, both the positive electrode layer and the negative electrode layer were printed in a pattern (arrangement) in which rectangular microcells shown in FIG. 1 were two-dimensionally arranged in a tile shape. At this time, as shown in FIG. 1, the positive electrode layer and the negative electrode layer were printed so as to be arranged at exactly the same position with the polymer electrolyte membrane (ion conductive layer) interposed therebetween. Further, in this example, the negative electrode layer and the positive electrode layer were printed so that the thickness (after drying) was 5 μm, and as shown in FIG. _The arrangement (pattern) configuration was such that ₁ = 10 mm and the gap distance D ₁ = 1 mm between the microcells. The thickness of the current collecting layer was 5 μm, and the size of the current collecting layer was the same as the size of the A4-size fine paper.

  The laminate in which the negative electrode layer, the polymer electrolyte membrane (ion conductive layer) and the positive electrode layer were laminated was sandwiched between two stainless steel foils as a current collecting layer. Finally, the battery was sealed and molded with the same aluminum laminate material as in Example 1 so that only the positive and negative electrode leads came out of the battery.

<Evaluation>
The charge / discharge characteristics were evaluated in the same manner as in Example 1. As a result of the charge / discharge evaluation, a charge / discharge plateau was observed in the vicinity of an average voltage of about 3.8 V, and it was confirmed that the produced battery was functioning.

(Example 4)
A battery was prepared using the ink prepared without using a solvent according to the following procedure.

<Preparation of negative electrode ink>
A negative electrode active material (60% by mass), a polymer electrolyte raw material (27% by mass), a lithium salt (13% by mass), and a photopolymerization initiator (0.1% by mass with respect to the polymer electrolyte raw material) were prepared. These were sufficiently stirred to prepare a slurry as a negative electrode ink. The viscosity of this ink at room temperature was about 200 cP. The viscosity at 60 ° C. was about 20 cP.

<Preparation of positive electrode ink>
Positive electrode active material (47% by mass), acetylene black (13% by mass) as a conductive material, polymer electrolyte material (27% by mass), lithium salt (13% by mass), and photopolymerization initiator (based on polymer electrolyte material) 0.1 mass%) was prepared. These were sufficiently stirred to prepare a slurry as a positive electrode ink. The viscosity of this ink at room temperature was about 200 cP. The viscosity at 60 ° C. was about 20 cP.

<Preparation of electrolyte ink>
A polymer electrolyte raw material (15% by mass), a lithium salt (8% by mass), and a photopolymerization initiator (0.1% by mass with respect to the polymer electrolyte raw material) were prepared. These were sufficiently stirred to prepare a slurry as an electrolyte ink. The viscosity of this ink at room temperature was about 200 cP. The viscosity at 60 ° C. was about 20 cP.

<Production of battery>
A battery was prepared according to the following procedure using the prepared ink and an experimental ink jet printer. The experimental ink jet printer has a piezo element type head, and can apply an applied voltage up to 200V. In addition, an ink heating heater is provided, and the ink temperature can be controlled from room temperature to 100 ° C.

  A negative electrode ink was introduced into an experimental inkjet printer, and a pattern created on a computer (in this example, a pattern in which rectangular microcells shown in FIG. 1 were two-dimensionally arranged in a tile shape) was collected. Printed on a stainless steel foil as a layer. The ink temperature was set to 60 ° C. After printing, in order to polymerize the polymer electrolyte raw material, ultraviolet rays were irradiated for 20 minutes in a vacuum to obtain a laminate in which the negative electrode layer was laminated on the current collecting layer.

  The electrolyte ink was introduced into an experimental inkjet printer, and the electrolyte ink was printed on the negative electrode layer so as to have the same pattern as the negative electrode layer. The ink temperature was set to 60 ° C. The formed polymer electrolyte membrane (ion conductive layer) was uniformly formed with no unevenness. After printing, in order to polymerize the polymer electrolyte raw material, ultraviolet rays were irradiated for 20 minutes in a vacuum to obtain a laminate of a current collecting layer, a negative electrode layer, and a polymer electrolyte membrane (ion conductive layer).

Similarly, the positive electrode ink was printed on the polymer electrolyte membrane (ion conductive layer) so that the formed positive electrode layer had the same pattern as the negative electrode layer. The ink temperature was set to 60 ° C. After printing, in order to polymerize the polymer electrolyte raw material, ultraviolet rays were irradiated for 20 minutes in a vacuum to obtain a laminate of a current collecting layer, a negative electrode layer, a polymer electrolyte membrane (ion conductive layer), and a positive electrode layer. Further, in this example, the negative electrode layer, the polymer electrolyte membrane (ion conductive layer), and the positive electrode layer were printed so that the thickness (after drying) was 5 μm, and as shown in FIG. The arrangement (pattern) configuration was such that the length L ₁ of each of the negative electrode and ion conduction microcells was 10 mm, and the gap distance D ₁ between the microcells was ₁ mm. The thickness of the current collecting layer was 5 μm, and the size of the current collecting layer was the same as the size of the A4-size fine paper.

  This laminate was sandwiched between stainless foils as a current collecting layer. Finally, the battery was sealed and molded with the same aluminum laminate material as in Example 1 so that only the positive and negative electrode leads came out of the battery.

<Evaluation>
The charge / discharge characteristics were evaluated in the same manner as in Example 1. As a result of the charge / discharge evaluation, a charge / discharge plateau was observed in the vicinity of an average voltage of about 3.8 V, and it was confirmed that the produced battery was functioning.

(Example 5)
A liquid lithium ion battery was produced according to the following procedure for Examples 1 to 4 which are polymer electrolyte batteries.

<Preparation of negative electrode ink>
A negative electrode active material (9% by mass), polyvinylidene fluoride (PVdF; 1% by mass), and N-methyl-2-pyrrolidone (NMP; 90% by mass) were prepared as solvents. These were sufficiently stirred to prepare a slurry as a negative electrode ink. The viscosity of this ink was about 5 cP.

<Preparation of positive electrode ink>
A positive electrode active material (7% by mass), acetylene black (2% by mass) as a conductive material, PVdF (1% by mass), and NMP (90% by mass) as a solvent were prepared. These were sufficiently stirred to prepare a slurry as a positive electrode ink. The viscosity of this ink was about 4 cP.

<Production of battery>
A battery was prepared according to the following procedure using the prepared ink and a commercially available ink jet printer. In addition, when said ink was used, there existed a problem that NMP which is a solvent will melt | dissolve the plastic component in the ink introduction part of an inkjet printer. Therefore, printing was performed with a printer having the same modifications as in Examples 1 to 3.

  A negative ink was introduced into a modified ink jet printer and a pattern created on a computer (in this example, a pattern in which rectangular micro cells shown in FIG. 1 are two-dimensionally tiled) was used. It printed on the copper foil as a current collection layer for negative electrodes. After printing, in order to dry the solvent, drying was performed in a 120 ° C. vacuum oven for 12 hours. After drying, press working was performed with a roll press so that the coating film density was 1.3 g / cc or more, and the negative electrode was completed.

A positive ink was introduced into a modified ink jet printer and a pattern created on a computer (in this example, a pattern in which rectangular micro cells shown in FIG. 1 were two-dimensionally installed in a tile shape. As shown in FIG. 1, the positive electrode layer and the negative electrode layer are arranged at exactly the same position (opposing positions) with an electrolyte layer (ion conductive layer) formed by impregnating a polyethylene microporous membrane separator described later with an electrolyte solution interposed therebetween. Was printed on an aluminum foil as a positive electrode current collecting layer. After printing, in order to dry the solvent, drying was performed in a 120 ° C. vacuum oven for 12 hours. After drying, press working was performed with a roll press so that the coating film density was 2.0 g / cc or more, and the positive electrode was completed. In this embodiment, the negative electrode layer and positive electrode layer thickness (after drying) is printed so both the 5 [mu] m, as shown in Figure 1, each micro cell for the positive electrode and the negative length L ₁ = The arrangement (pattern) configuration was 10 mm, and the gap distance D ₁ = 1 mm between minute cells. The thickness of the current collecting layer was 5 μm, and the size of the current collecting layer was the same as the size of the A4-size fine paper.

The produced positive electrode and negative electrode were punched into a 10 cm square (100 cm ² ), laminated via a 25 μm thick polyethylene microporous membrane separator, and sealed with a laminate outer packaging material to obtain an evaluation cell. As the electrolytic solution, a mixed solvent of ethylene carbonate (EC) and dimethyl carbonate (DMC) with a volume fraction of 3: 7 containing lithium hexafluorophosphate (LiPF ₆ ) at a concentration of 1 mol / liter was used.

<Evaluation>
The manufactured battery was subjected to constant current / constant voltage charging at ²⁰ μA / cm ^{2 at} an upper limit voltage of 4.2 V, and then constant current discharge at ²⁰ μA / cm ² was performed at a lower limit voltage of 2.5 V. As a result of the charge / discharge evaluation, a charge / discharge plateau was observed in the vicinity of an average voltage of about 3.8 V, and it was confirmed that the produced battery was functioning.

10, 40, 60, 80, 90, 100, 110, 120 Secondary battery electrode,
11, 41, 61, 81, 91, 101, 111, 121 current collecting layer,
12, 42, 62, 82, 82 ', 92, 102, 102a, 102b, 112, 122 microcell for positive electrode,
13, 43, 63, 123 Microcell for negative electrode,
14, 44, 64, 124 Microcell for ion conduction,
20, 31, 50, 70 secondary battery,
33 surface with curvature,
113 heat exchanger,
125 heat conduction layer,
131 A flat polymer lithium ion secondary battery that is not a bipolar type,
133 Battery exterior material,
135 positive electrode current collector,
137 positive electrode active material layer,
139 electrolyte layer,
141 negative electrode current collector,
143 negative electrode active material layer,
145 electrode laminate,
147 positive lead,
149 negative electrode lead,
151 Bipolar polymer lithium ion secondary battery,
153 current collector,
155 positive electrode (positive electrode active material layer),
155a, the lowermost positive electrode active material layer,
157a, the uppermost negative electrode active material layer,
157 negative electrode (negative electrode active material layer),
159 bipolar electrode,
161 electrolyte layer,
163 electrode laminate (bipolar battery body),
165 positive lead,
167 negative lead,
169 Battery exterior material.

Claims (4)

The electrode layer on the substrate is composed of a plurality of microcells having different resistance values or capacities,
The microcell is arranged such that the resistance value or the capacitance is two-dimensionally or one-dimensionally inclined so that the electrode layer relieves stress and / or thermal stress. Secondary battery electrode.   The electrode for a secondary battery according to claim 1, wherein the minute cells having different resistance values or capacities are alternately arranged.   3. The electrode for a secondary battery according to claim 1, wherein a material having a good thermal conductivity is disposed in a gap between the microcells having different resistance values or capacities.   The electrode for a secondary battery according to any one of claims 1 to 3, wherein the ratio of the conductive material is changed in units of minute cells that are produced by an inkjet method and constitute the electrode layer.

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