JP2005135599A - Ultra-thin film electrode for high-output battery, and the high-output battery using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode for a high-output battery having high energy density, capable of extracting energy necessary for carrying out charge/discharge at a large current through turning an electrode active material into microparticles. <P>SOLUTION: The electrode for the battery is provided with a current collector 15 and an electrode layer 11 formed on the current collector. Conductive fine particles 12a in the electrode layer are in a state of being in contact with each other, up to the surface of the collector in the thickness direction of the layer, and a part of the surface of electrode active material fine particles 13a in the electrode layer is in a state of contact with the conductive fine particles. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a small (ultra-thin film) high-power battery electrode, and particularly a small (ultra-thin film) high-power battery electrode suitable as a motor driving battery for an electric vehicle or the like by combining a plurality of high-power batteries. The present invention relates to the high power battery used.

  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 overcharging or the like, it has less impact than a metal container. Therefore, it is suitable as a battery for driving a motor.
JP2003-151526A

  However, in such a thin laminated battery, when manufacturing a positive electrode or 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.

That is, it is excellent in that a positive electrode layer and a negative electrode layer having a uniform thickness can be formed on the current collector foil by applying a positive electrode material and a negative electrode material with a coater. Furthermore, the component composition or configuration of the electrode layer formed on one current collector foil is an excellent electrode coating method that can provide an extremely uniform electrode that is uniform throughout without any local bias. Furthermore, in the electrode material used for coater coating, in order to ensure electron conductivity, particles of the electrode active material (current average particle size is about 10 μm) and conductive material fine particles (current secondary particle average particle size is about 0.1 μm). Around 1 μm). As a result, about 20 layers of conductive material fine particles are coated on the entire surface of the electrode active material particles. On the other hand, in order to obtain a high-power battery that can be used as a power source for driving a vehicle, it is necessary to stack several tens to hundreds of electrodes in one battery. Is strongly demanded. In order to achieve further reduction in the thickness of the electrode, it is indispensable to make the electrode active material fine particles (average particle size of 1 μm or less). However, by making the electrode active material finer, the particle size becomes substantially the same as the conductive material fine particles (specifically, the average particle size is 1 μm or less). Then, the contact between the electrode active material and the conductive material becomes difficult and the internal resistance of the electrode layer increases,
There has been a problem that a new technical problem of reducing conductivity and utilization rate occurs. Therefore, in order to ensure the electron conductivity, in order for the conductive material fine particles having the same size to adhere to the entire surface of the electrode active material fine particles, it is necessary to relatively increase the proportion of the conductive material fine particles. However, increasing the proportion of the conductive material fine particles makes it difficult for lithium ions (hereinafter also referred to as Li ions) to reach the surface of the electrode active material. As a result, it was found that, when charging / discharging with a large current, a new technical problem arises that the necessary energy cannot be taken out due to the depletion of lithium ions as a reactant. For this reason, it is the present situation that electrode active material micronization (use of electrode active material microparticles having an average particle size of 1 μm or less), which is one of the important elemental technologies for electrode thinning, has not been achieved.

  Accordingly, an object of the present invention is to provide an electrode for an ultra-thin high-power battery capable of taking out necessary energy even when electrode active material is made into fine particles and charging / discharging with a large current is performed. It is to be.

  The present invention relates to a battery electrode comprising a current collector and an electrode layer formed on the current collector, and the current is collected in the electrode layer thickness direction between the conductive material fine particles in the electrode layer. It can be achieved by an electrode for a high-power battery that is connected in contact with the body surface, and a part of the surface of the electrode active material fine particles in the electrode layer is in contact with the conductive material fine particles .

  According to the present invention, the entire surface of the finely divided electrode active material is not covered with the conductive material fine particles, and a part thereof is in contact with the conductive material fine particles electrically connected to the current collector. Therefore, good electron conductivity can be ensured. In other words, in an electrode in which fine particles are arranged so that the electrode active material and the conductive material are in close contact, and a conductive path of the conductive material is formed from the top to the bottom in the thickness direction of the electrode layer, the conductivity and the utilization factor are reduced. It is possible to provide an electrode for an ultra-thin high-power battery that does not cause this. Therefore, even if the proportion of the conductive material is not increased as the electrode active material becomes finer, the internal resistance can be lowered by forming the conductive path by arranging the conductive material at an arbitrary position. In addition, when charging / discharging with a large current, necessary energy can be taken out (high output can be achieved), and thinning of the electrode can also be achieved (see FIG. 10). Therefore, high-power battery electrodes that can be charged / discharged with high voltage and large current with thin, lightweight, compact, high output, and high output using this ultra-thin electrode layered with tens to hundreds of electrodes. Battery can be provided. High-power battery electrodes that can be suitably used for applications that require high output and high energy density, such as EV, HEV, and FCV motor drive power supplies, and high output using this Battery can be provided.

The electrode for a high-power battery of the present invention is a battery electrode having a current collector and an electrode layer formed on the current collector, and the electrode layer is formed between the conductive material fine particles in the electrode layer. It is connected in a state of being in contact with the current collector surface in the thickness direction, and a part of the surface of the electrode active material fine particles in the electrode layer is in a state of being in contact with the conductive material fine particles. is there. In the high power battery electrode of the present invention, the conductive material portion mainly composed of the conductive material fine particles and the electrode active material portion mainly composed of the electrode active material fine particles are dispersed in the electrode layer. The conductive material fine particles in the conductive material portion are connected in a state in which they are in contact with each other from the surface of the electrode layer to the surface of the current collector in the thickness direction of the electrode layer. It is desirable that each of the electrode active material fine particles in the part is arranged so that a part of the surface is in contact with the conductive material fine particles in the adjacent conductive material part. Further, the conductive material portion and the electrode active material portion constituting the electrode layer are two-dimensionally dispersed in a plane direction perpendicular to the thickness direction of the electrode layer, that is, preferably substantially uniformly dispersed. It is more desirable that they are arranged (arranged). And it can be said that it is especially desirable that the arrangement (arrangement) of these electrode layers is formed using, for example, a coating method for printing by an inkjet method. That is, it can be said that it is particularly desirable that the conductive material and the active material are formed using a method that can be applied separately in separate steps.

  In the present application, the conductive material fine particles are connected from the electrode layer surface to the current collector surface as an example. However, the present invention is not limited to this. For example, in order to simplify the process, at least from the current collector surface. It goes without saying that a part of the effect can be obtained even if the structure of the present application is used up to about 5 μm and a current collector layer is formed by applying a mixture of a conductive material and an active material as in the prior art. Therefore, it can be said that the connection length of the conductive material fine particles is desirably 5 μm or more.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of ultrathin high-power battery electrodes according to the present invention will be described below with reference to the drawings.

  1 to 6 are schematic views schematically showing typical embodiments of the ultra-thin high-power battery electrode of the present invention. Among these, FIG. 1 (a) shows one of a conductive material and an electrode active material of an electrode layer in a high power battery electrode comprising a current collector and an electrode layer formed on the current collector. FIG. 1B is a schematic cross-sectional view schematically showing an arrangement configuration, and FIG. 1B is a schematic plan view of FIG. 2 to 6 show different arrangement configurations of the conductive material of the electrode layer and the electrode active material in the electrode for the high power battery comprising the current collector and the electrode layer formed on the current collector. It is the plane schematic diagram typically expressed. FIG. 6 schematically shows a further different arrangement configuration of the conductive material and the electrode active material of the electrode layer in the electrode for the high-power battery comprising the current collector and the electrode layer formed on the current collector. FIG.

  In the electrode layer of the embodiment shown in FIG. 1 (applied to the positive electrode layer of Example 1), as shown in FIG. 1A, the surface direction perpendicular to the electrode layer thickness direction (hereinafter simply referred to as the surface direction). Is also a pattern in which one conductive material fine particle is arranged per four positive electrode active material fine particles 13a. In addition, as shown in FIG. 1A, the thickness direction is the same as the arrangement in the plane direction of FIG. 1B (two-dimensional plane arrangement, the same shall apply hereinafter) perpendicular to the thickness direction. Then, an active material part 13 formed by connecting (stacking) active material fine particles 13a around a conductive material part (conductive path) 12 formed (stacked) by connecting and stacking conductive material fine particles 12a in the thickness direction is formed. The arranged pattern is shown.

  In the electrode layer of the embodiment shown in FIG. 2 (applied to the positive electrode layer of Example 2), the surface direction shows a pattern in which two conductive material fine particles 12a are arranged per one positive electrode active material particle 13a. In this example, the two positive electrode active material particles 13a are arranged so that the two conductive material fine particles 12a face each other (opposite). The thickness direction is the same as that of the embodiment shown in FIG. That is, the plane direction arrangement of FIG. 2 is laminated in the thickness direction as it is, and the active material fine particles 13a are connected around the conductive material portion 12 formed (laminated) by connecting the conductive material fine particles 12a in the thickness direction. A pattern in which the formed (laminated) active material portion 13 is arranged is shown (the thickness direction of the following embodiments of FIGS. 3 to 5 is the same as that of the embodiment shown in FIG. ).

  In the electrode layer of the embodiment shown in FIG. 3 (applied to the positive electrode layer of Example 3), the surface direction indicates a pattern in which two conductive material fine particles 12a are arranged in contact with each positive electrode active material particle 13a. . In this example, the two positive electrode active material particles 13a are arranged so that the two conductive material fine particles 12a face each other (opposite). The thickness direction is the same as that of the embodiment shown in FIG.

  In the electrode layer of the embodiment shown in FIG. 4 (applied to the positive electrode layer of Example 4), the surface direction is another pattern in which three conductive material fine particles 12a are arranged in contact with each positive electrode active material particle 13a. An example of The thickness direction is the same as that of the embodiment shown in FIG.

In the electrode layer of the embodiment shown in FIG. 5 (applied to the positive electrode layer of Example 5), the surface direction shows a pattern in which four conductive material fine particles 12a are arranged in contact with each positive electrode active material particle 13a. . The thickness direction is the same as that of the embodiment shown in FIG.

  In the example of FIGS. 1 to 5, as shown in Examples 1 to 5 described later, the ratio of the conductive material in the electrode layer can be changed by changing the arrangement of the conductive material and the active material. Accordingly, as shown in FIG. 9 and FIG. 10, the relationship between the proportion of the conductive material and the internal resistance or the internal resistance ratio (this is specified in detail in the embodiment, so the description thereof is omitted here). In addition, design the electrode that meets the purpose of use from the relationship between the utilization factor (the lower the proportion of the conductive material, the higher the utilization factor) and the conductivity (the lower the internal resistance or internal resistance ratio, the higher the conductivity). Is something that can be done. In the examples to be described later, by arranging the conductive material and the finely divided active material at arbitrary positions, the conductive material is at least about 30 to 60% higher than the conventional coating method using a coater. Sufficient performance can be achieved as an output battery electrode. Moreover, since the ratio of an active material will increase relatively if the ratio of a electrically conductive material becomes low, a utilization factor can also be raised.

  In the electrode layer of the embodiment shown in FIG. 6 (applied to the positive electrode layer of Example 6), the active material fine particles 13a in the electrode layer 11 are formed (laminated) straightly connected in the thickness direction (laminated). A pattern in which the conductive material fine particles 12a are arranged in contact with each other in a spiral manner is provided. The spiral conductive material fine particles 12a are connected to each other in the thickness direction of the electrode layer 11 from the surface of the electrode layer 11 to the surface of the current collector 15. One conductive material portion (conductive path) 12 is constructed. Further, in the present embodiment, it is desirable to use a pattern in which an electrolyte portion (not shown) is arranged around the active material portion using electrolyte ink in portions other than the conductive material fine particles around the active material portion 13. Thereby, it can be set as the structure which disperse | distributed and arrange | positioned the electrically-conductive material part 12 and the electrode active material part 13 in three dimensions (three-dimensional).

  The above is the description of the arrangement (arrangement) configuration example of the conductive material and the electrode active material in the electrode layer in the ultra-thin high-power battery electrode of the present invention. Needless to say, it should not be restricted at all.

  That is, in the present invention, the conductive material fine particles constituting the conductive material part 12 are connected in a state in which they are in contact with each other in the electrode layer thickness direction from the electrode layer surface to the current collector surface, thereby forming the electrode active material part 13. As long as a part of the surface of the electrode active material fine particles to be in contact with the conductive material fine particles is not particularly limited.

First, it is only necessary that a part of the surface of the electrode active material fine particles in the electrode layer is in contact with the conductive material fine particles. More specifically, a plurality of active material portions 13 mainly composed of the active material fine particles 13a are formed in the electrode layer 11, and only a part of the surface of the active material fine particles 13a in the active material portion 13 is formed. It can also be said that they are arranged in contact with the conductive material fine particles 12a in the adjacent conductive material portions 12. In addition, it can be said that the conductive material portion 12 and the active material portion 13 have a microelectrode structure in which the conductive material portion 12 and the active material portion 13 are dispersed in the electrode layer (FIG. 1B, FIGS. 2 to 5). See More specifically, these many conductive material portions 12 and active material portions 13 are preferably dispersed in a plane direction (see FIG. 1A) perpendicular to the thickness direction of the electrode layer 11, They are arranged (arranged) approximately uniformly. Examples of the arrangement (arrangement) in the plane direction of the conductive material portion 12 and the active material portion 13 include those shown in FIG. 1B and FIGS. 2 to 5, but are not limited thereto. For example, the conductive material portion 12 and the active material portion 13 may be arranged in a plane direction like a sea-island structure. In this case, the sea side may be the conductive material portion 12 or the active material portion 13. The arrangement (arrangement) in the surface direction may or may not be uniform over the entire surface. Moreover, it may be regular or irregular. Further, the arrangement (arrangement) in the regular plane direction may not be the entire electrode layer, and a portion having regularity and an irregular portion may be mixed in the electrode layer. Further, in the plurality of electrodes constituting the battery, the arrangement (arrangement) in the surface direction of the conductive material portion 12 and the electrode active material portion 13 for each electrode may be the same or different. .

  Secondly, it is only necessary that the conductive material fine particles in the electrode layer are connected in the electrode layer thickness direction from the electrode layer surface to the current collector surface. As a result, a conductive material portion (conductive path) is formed. More specifically, a plurality of conductive material portions 12 mainly composed of the conductive material fine particles 12 a are formed in the electrode layer 11, and the space between the conductive material fine particles 12 a in each conductive material portion 12 is between the electrode layers 11. It can also be said that the electrode layers 11 are arranged (arranged) so as to be in contact with each other in the thickness direction from the surface to the surface of the current collector 15. Regarding the embodiment of the arrangement (arrangement) in the thickness direction, the embodiment of the arrangement (arrangement) in the plane direction is the same. That is, as an example of the arrangement (arrangement) of the conductive material portion 12 and the active material portion 13 in the thickness direction of the electrode layer, as shown in FIG. Although the arrangement | sequence connected to the electrical power collector in the laminated | stacked form can be illustrated, it is not restrict | limited to this. For example, the arrangement (arrangement) in the thickness direction of the conductive material portion 12 and the active material portion 13 is such that the conductive material portion 13 spirally contacts the active material portion 12 as shown in FIG. Or may be connected to a current collector by being networked in a three-dimensional lattice shape (three-dimensional mesh shape). Furthermore, the conductive material portion 12 may be connected linearly in a so-called vertical direction or with an appropriate inclination angle in the electrode layer thickness direction. Furthermore, the conductive material portion 12 may have an arbitrary arrangement (arrangement), such as being connected in a dendritic shape (three-dimensional structure) from the current collector toward the electrode layer surface. Preferably, the shortest distance connecting the electrode layer surface and the current collector surface is linearly connected, that is, from the viewpoint of improving the electron conductivity (see FIG. 1A).

  In the present invention, the electrode active material and the conductive material that have been atomized can be one-dimensionally (linearly) or two-dimensionally (planarly) by using a print-coating method that can be patterned and applied, particularly an ink-jet printing method. In addition, even if it is a fine and complicated arrangement (microelectrode structure) at an arbitrary position three-dimensionally (three-dimensionally), the electrode layer can be easily arranged (arranged). As a result, an ultra-thin high-power battery electrode can be produced without degrading conductivity and utilization. As a result, it is possible to provide a high output battery power suitable for a vehicle-mounted power source. Furthermore, the battery can be reduced in size and weight, and the total weight and total volume of the on-vehicle power source can be reduced.

  Here, the reason why the conductive material portion is mainly composed of the conductive material fine particles is that the conductive material fine particles may contain a binder or the like in order to connect the conductive material fine particles. The same applies to the active material part.

In addition, as described above, it is necessary that only a part of the surface of the active material fine particles in the electrode layer is in contact with the conductive material fine particles. That is, the conductive path can be formed without covering the entire surface of the active material fine particles with the conductive material fine particles, and the active material fine particles can be brought into contact with the electrolyte (electrolytic solution) which is an ion conductive material. For example, an electrolytic solution (or electrolyte) is present in the space between the conductive material fine particles 12a and the active material fine particles 13a in FIGS. 1 to 6 (not shown. For details, refer to Examples described later). In this way, the active material can be made fine particles while ensuring ionic conductivity. That is, when the entire surface of the active material fine particles is covered with the conductive material fine particles as the active material becomes finer, it is necessary to increase the ratio of the conductive material, which increases the internal resistance. However, the electrode structure of the present invention is adopted. Thus, since there are no coating layers of 20 conductive material fine particles, a structure in which Li ions can easily enter and exit can be obtained. Therefore, the internal resistance of the electrode can be reduced without increasing the proportion of the conductive material in the electrode layer (see FIGS. 9 and 10). Therefore, stable charging / discharging (power supply) can be continued without causing depletion of Li ions when charging / discharging with a large current. Further, as shown in FIG. 1A, sufficient electron conductivity is ensured by forming the conductive material portion (conductive path) 12 in a state where a part of the surface of the active material fine particles 13a is in contact with the conductive material fine particles 12a. can do. In the above description, an example is shown in which electrons are generated by an electrode reaction, but the exchange of electrons is reversed between the positive electrode side and the negative electrode side, or during charging and discharging. In that case, electrons move from the current collector through the conductive material portion (conductive path) to the active material fine particle side, the electrode reaction proceeds, and Li ions are released.

  1 to 6, the circles in the drawings correspond to one conductive material fine particle 12a or active material fine particle 13a. However, in the present invention, since the coating method is an ink jet printing method, the conductive material ions or It can also be viewed as representing a single drop of active material ink. That is, in the present invention, the conductive material fine particles 12a or the active material fine particles 13a can be controlled to be one while the conductive material ions or the active material ink is suitable, but the configuration of the present invention can be realized even if there are two or more. It can be done. However, since the size of the secondary particles varies depending on the average particle size, it can be said that the diameter of the secondary particles may be 1 μm or less. The same applies to the coating method for screen printing.

  In addition, the average particle diameter of the active material fine particles is obtained from the viewpoint of providing an electrode for a secondary battery with high output that can be used for a power source for driving a vehicle, etc. The range of 10 μm or less, preferably 1 μm or less, more preferably 0.05 to 1 μm, particularly preferably 0.1 to 1 μm is desirable. On the other hand, when the average particle diameter of the active material fine particles exceeds 10 μm, it becomes difficult to achieve further thinning of the electrode, and the effects of the present invention cannot be fully expressed. The lower limit of the average particle diameter of the active material fine particles is not particularly limited, but if it is less than 0.05 μm, it may be difficult to produce and preferable discharge characteristics may not be obtained.

  The average particle diameter of the conductive material fine particles is 1 μm or less, preferably 0.1 to 0.05 μm, from the viewpoint of further thinning of the electrode. When the average particle diameter of the conductive material fine particles exceeds 1 μm, it becomes difficult to achieve further thinning of the electrode, and the effects of the present invention cannot be fully expressed. On the other hand, the lower limit value of the average particle size of the conductive material fine particles is not particularly limited from the viewpoint of further thinning of the electrode.

  Further, the ratio (mass ratio) of the conductive material in the electrode layer is appropriately determined according to the fine particle size of the conductive material and the electrode active material, the arrangement (arrangement) configuration of the conductive material portion and the electrode active material portion, and the like. is there. For example, as shown in Examples 1 to 5 to be described later, the relationship between the ratio (concentration) of the conductive material and the internal resistance depending on the fine particle size of the conductive material and the electrode active material and its arrangement (arrangement) (see FIGS. 9 and 10). Graph) can be obtained, and the optimal proportion of the conductive material (conductive material concentration) can be determined. For example, when the average particle diameter of the active material fine particles is 1 μm or less, the ratio (mass ratio) of the conductive material is 2 to 10% by mass, preferably 2% by mass to the total amount of the electrode layer to which the present invention is applied. It is in the range of 4 to 6% by mass. When the ratio (mass ratio) of the conductive material exceeds 10% by mass, the utilization factor decreases, and the conductive material covers the entire active material surface, which may cause a decrease in ion conductivity. When the ratio (mass ratio) of the conductive material is less than 2% by mass, it may be difficult to obtain the electrode structure of the present invention, and it may be difficult to ensure sufficient electronic conductivity.

  In the electrode of the present invention, in the case of an electrode for a liquid electrolyte type high power battery using a liquid electrolyte for the electrolyte layer, the electrode layer is impregnated when the separator in the battery is impregnated by injection or the like. It can be said that the electrolyte does not need to be further contained in the electrode layer because the electrolytic solution penetrates into the voids such as between the electrode active material and the fine particles of the conductive material. However, it goes without saying that a polymer electrolyte may be included if necessary according to the intended use.

On the other hand, in the case of an electrode for a polymer electrolyte type high-power battery using a polymer gel electrolyte or a polymer solid electrolyte in the electrolyte layer, it is preferable that the polymer electrolyte is contained in the electrode layer. It is preferable in securing the above. Specifically, (1) the electrode active material part in the electrode layer may further contain a polymer electrolyte. (2) The electrode layer may be arranged (arranged) in the electrode layer so that a polymer electrolyte part mainly composed of a polymer electrolyte is in contact with the active material part. For example, FIG.
b) The electrolyte part may be formed in the void part of FIGS. 2 to 6 by an ink-jet printing application method using electrolyte ink, but is not limited thereto. From the viewpoint of ensuring contact between the electrode active material fine particles and the conductive material fine particles, the latter form (2) can be said to be desirable.

  Furthermore, a good heat conduction portion and / or a void portion mainly composed of a material having good heat conductivity may be disposed in the electrode layer. When the electrode is thinned and laminated in multiple layers, heat is likely to be trapped in the central part rather than the peripheral part of the electrode. It is excellent in that it can. In the present invention, an electrode is formed using a coating method for printing by an ink jet method, thereby enabling arrangement (pattern) having different characteristics in such an electrode layer.

  In the present invention, the electrode layer means a positive electrode layer and / or a negative electrode layer. In addition, the high-power battery electrode may have a current collector and an electrode layer formed on the current collector, and includes a positive electrode, a negative electrode, and a bipolar electrode. In other words, a non-bipolar positive electrode has a structure in which a positive electrode layer is formed on both sides of a current collector, a negative electrode has a structure in which a negative electrode layer is formed on both sides of the current collector, and a bipolar electrode has In this structure, a positive electrode layer is formed on one surface and a negative electrode layer is formed on the other surface.

  In the present invention, the electrode layer is preferably formed using a printing application method such as ink jet printing, screen printing, or an air brush method, and is formed using an ink jet printing method. It is more desirable. This is because the patterning coating of the microelectrode structure of the present invention, which cannot be formed by a conventional coating technique using a coater, can be easily performed. Furthermore, there is no need to prepare different screens for each pattern as in screen printing, and there is no need for replacement. That is, the planar or three-dimensional arrangement of the electrode layers on the printing screen of the computer software (printing software) connected to the ink jet printer (for example, the arrangement of the conductive material portion and the electrode active material portion, or each conductive material portion and the electrode active material) Color corresponding to the composition and material of the constituent components of the conductive material part and the electrode active material part, the polymer electrolyte part, the good heat conduction part, and the gap part provided as necessary. Can be changed. In other words, when changing the composition or material of the constituent components, if necessary, the ink cartridge of the ink jet printer can be replaced or the number of cartridges can be increased or decreased according to the change in color (color) display on the printing screen. Well, it is very easy to deal with design changes. As used herein, the term “ink” refers to a raw material used to form a positive electrode layer, a negative electrode layer, and further an electrolyte layer (a constituent element of a high-power battery described later). It shall mean the raw material slurry obtained by adjusting. For example, the material slurry for forming the conductive material part of the positive electrode layer is the positive electrode conductive material ink, the material slurry for forming the positive electrode active material part of the positive electrode layer is the positive electrode active material ink, and the material slurry for forming the conductive material part of the negative electrode layer is the negative electrode Conductive material ink, negative electrode active material portion forming material slurry for negative electrode layer, negative electrode active material ink, electrolyte layer (or electrolyte portion) forming material slurry for electrolyte ink (collectively these are also simply referred to as slurry or ink) And so on (refer to Examples described later).

  Here, a coating method (also simply referred to as an ink jet method) for printing by an ink jet method is a current collector (or an electrolyte) in which positive / negative electrode active material ink, positive / negative electrode conductive material ink, electrolyte ink, and the like are droplets from an ink jet nozzle. It is the method of apply | coating on base materials, such as a layer and a separator. As a result, a desired uniform and thin coating film thickness can be formed in a required region on the current collector (or a substrate such as an electrolyte layer or a separator). Since negative electrode conductive material ink, electrolyte ink, etc. can be apply | coated, it is preferable.

Furthermore, it is desirable that the ink jet method is an ink jet method using a piezoelectric element. The ink jet method using a piezo element is a method using a piezo type, which is generally known as a drop-on-demand method, and discharges a liquid using a ceramic (piezo element) that deforms when a voltage is applied. The ink jet method using a piezo element is excellent in thermal stability of electrode materials and polymer materials contained in positive / negative electrode active material ink, positive / negative electrode conductive material ink, electrolyte ink, etc., and the amount of each ink applied can be varied. can do. Furthermore, a relatively high-viscosity liquid can be discharged reliably, stably and accurately compared to other inkjet heads, and can be effectively used for discharging a liquid having a viscosity of up to 10 Pa · s (100 cP). Excellent in terms.

  In the piezo-type ink jet head, generally, a liquid chamber for storing each ink is formed, and this liquid chamber has a structure connected to the liquid chamber via an ink introducing portion. A large number of nozzles are arranged in a lower portion of the inkjet head. In addition, a piezoelectric element for ejecting ink in the liquid chamber from the nozzle and a driver for operating the piezoelectric element are disposed in an upper part of the inkjet head. The structure of such an inkjet head is merely an embodiment and is not particularly limited.

  When the ink introduction part is made of plastic, a solvent that can be contained in each ink may dissolve the plastic part. Therefore, the ink introduction part is preferably made of metal having excellent solvent resistance.

  Further, it is preferable to use an ink having a viscosity at 25 ° C. of 0.1 to 100 cP, preferably 0.5 to 10 cP, more preferably 1 to 3 cP. If the viscosity of each ink is less than 0.1 cP, it may be difficult to control the flow rate, and if it exceeds 100 cP, the above range is preferable because it may not pass through the nozzle.

  In the high power battery electrode of the present invention, the thickness of the electrode layer is desirably 10 μm or less, preferably 1 to 5 μm from the viewpoint of thinning the electrode. This is because the electrode can be made thinner, and the battery can be made thinner, smaller and lighter. When the thickness of the electrode layer exceeds 10 μm, it may be difficult to reduce the thickness of the electrode which is the object of the present invention. The lower limit value of the electrode layer thickness is not particularly limited. Here, the thickness of the electrode layer refers to the thickness of the electrode layer formed on one side of the current collector.

  Next, the method for producing the electrode for a high-power battery of the present invention is not particularly limited, but the electrode layer thickness where the conductive material fine particles in the electrode layer reach from the electrode layer surface to the current collector surface. The electrode active material fine particles in the electrode layer are in contact with each other in a direction, and a part of the surface of the electrode active material fine particles is in contact with the conductive material fine particles. It is desirable to form the electrode layer by patterning and coating the material and the material mainly composed of the electrode active material. As a result, it is possible to form a microelectrode structure that cannot be obtained by a conventional coating method using a coater, that is, an electrode structure in which electrode active materials and conductive material fine particles are arranged at arbitrary positions.

  The print coating method is not particularly limited, and examples thereof include screen printing, a coating method for printing by an inkjet method, and the like, and a coating method for printing by an inkjet method is preferable. In addition, the ink jet method includes three methods, ie, a piezo element method, a thermal ink jet method, and a continuance method, all of which can be adopted. From the viewpoint of the thermal stability of the battery material, the piezo element method. It is desirable to use

The method of applying each ink by the ink jet method is not particularly limited. For example, (1) one ink jet head is provided for each ink, and the liquid ejection operations of the plurality of micro-diameter nozzles are controlled independently. (2) A plurality of inkjet heads are provided for each ink, and the liquid ejection operation of these inkjet heads is controlled independently. And a method of applying droplets in an optimal pattern on the surface of the current collector (or substrate). By such a method, a desired optimum pattern can be formed in a short time.

  In the above (1) and (2), there is no particular limitation on independently controlling the liquid ejection operation. For example, an inkjet printer using the above-described inkjet head is connected to a commercially available computer or the like, and Power Point ( A desired pattern may be created by software such as Microsoft CAD (manufactured by Microsoft) or AutoCAD (manufactured by AutoDesk) and controlled by an electrical signal from such software.

  As a method of applying each ink in an optimal pattern on the current collector (or substrate) using the method (1) or (2) above, a plurality of minute diameters for one or a plurality of inkjet heads provided After the liquid ejection operation of the nozzles is controlled independently and each ink is patterned on the surface of the current collector (or base material) to form a thin film layer (planar arrangement), the same or different arrangement configuration A method of obtaining a desired electrode layer structure by repeating a process of applying each ink by patterning to form a thin film layer, and laminating a plurality of layers so as to obtain a desired three-dimensional configuration. For example, in the case of the spiral arrangement (arrangement) of FIG. 6, different patterning coating is performed for each thin film layer. On the other hand, in the case of the arrangement (arrangement) of FIGS. 1 to 5, the same patterning application may be performed on each thin film layer.

  The thickness of the thin film layer is 10 μm or less, preferably 1 to 5 μm. If the thickness of the thin film layer exceeds 10 μm, it may be difficult to achieve a desired thin film of the electrode in order to form a three-dimensionally arranged electrode layer by laminating a large number. In addition, the lower limit value of the thickness of the thin film layer is not particularly limited. Further, in the electrode layer, the thicknesses of the plurality of thin film layers are not necessarily uniform, and may be determined as appropriate so as to obtain desired electrode characteristics.

  The particle diameter of each ink droplet ejected from the inkjet head is 500 pl or less, preferably 1 to 100 pl, from the viewpoint of thinning the electrode. The lower limit of the particle size of the droplet is not particularly limited, but when the particle size of the droplet exceeds 500 pl, the number of electrode active material fine particles contained in the droplet increases. Therefore, it may be difficult to form the electrode structure of the present invention. Therefore, even if the conductive ink droplet pattern is arranged adjacent to the formed electrode ink droplet pattern on the current collector (or base material), a part of the surface of each electrode active material fine particle is electrically conductive. It may be difficult to contact the fine material particles. That is, there are a large number of electrode active material fine particles that are not in contact with the conductive material fine particles in the center of the electrode ink droplet, and battery characteristics may not be sufficiently obtained during charging and discharging with a large current. On the other hand, in order to obtain liquid droplets of less than 1 pl, it is necessary to introduce an ultra-fine processing technique of a micro-diameter nozzle, which may increase the cost. In addition, it becomes difficult to produce active material fine particles corresponding to the fine nozzle.

  The means for drying each ink applied on the current collector (or base material) is 20 to 200 ° C., preferably 80 to 150 ° C. for 1 minute to 8 hours in a normal atmosphere, preferably a vacuum atmosphere. Preferably, it may be performed for 3 minutes to 1 hour. However, the present invention is not limited to this, and may be appropriately determined according to the amount of solvent contained in each applied ink.

  When the ink used does not contain a polymer electrolyte (all solid polymer electrolyte or polymer gel electrolyte), as shown in Examples 1 to 5 to be described later, each ink is applied and dried, and then the electrolyte is used. A slurry or electrolyte may be impregnated (or injected). The impregnation method is not particularly limited, and a very small amount can be supplied by using an applicator or a coater.

  The means for polymerizing the polymer material (electrolyte material) contained in each ink may be appropriately determined according to the polymerization initiator as shown in Example 6 described later. For example, a photopolymerization initiator is used. In the inert atmosphere such as argon or nitrogen, preferably in a vacuum atmosphere, 0 to 150 ° C., preferably 20 to 40 ° C., for 1 minute to 8 hours, preferably 3 minutes to 1 hour. Irradiate.

  The electrode of the present invention is not limited to the manufacturing method described above. For example, the ink may be produced by adding a polymer material, which is a raw material of the polymer electrolyte, a polymerization initiator, or the like to the ink from the beginning. Alternatively, the electrode layer may be formed by patterning and applying each ink on the electrolyte layer or the separator. In this case, a current collector may be laminated on the electrode layer after patterning and applying each ink to form the electrode layer.

  Next, a high-power battery according to the present invention is characterized by using the above-described electrode for a high-power battery of the present invention. By using such a high-power battery electrode, it is possible to provide an ultra-thin high-power battery having a high energy density that can extract necessary energy even when charging and discharging with a large current. .

  Further, the high-power battery of the present invention should not be limited at all except that the above-described electrode for a high-power battery of the present invention is used. Since the constituent requirements of the secondary battery for output can be used as appropriate, it will be briefly described here. In the present invention, as shown in Example 6 to be described later, in addition to the electrodes, the electrolyte layer Alternatively, it may be formed by using a coating method for printing by an inkjet method. By carrying out like this, it is excellent at the point which can manufacture an electrode layer and an electrolyte layer continuously.

The high-power battery according to the present invention is not particularly limited, such as a stacked (flat) battery or a wound (cylindrical) battery, when distinguished by the structure of the battery. It can be applied to any of these structures. Similarly, when distinguishing by the type of the electrolyte layer of the battery, there is no particular limitation, and any of a liquid electrolyte type battery, a polymer gel electrolyte type battery, and a solid polymer electrolyte (all solid electrolyte) type battery can be used. It can also be applied to. 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). It is not particularly limited, for example, it can be used by impregnating a separator (including a separator). In addition, when viewed from 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. . A bipolar battery is preferable. A bipolar battery is a battery in which a plurality of unit batteries each having a positive electrode layer on one side and a negative electrode layer 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. For this reason, the path of electron conduction corresponding to the length of the lead wire becomes long, and the output of the battery becomes low. On the other hand, since current flows in the vertical direction through the current collector in the bipolar battery, the path of electron conduction is remarkably shortened, and the output is increased accordingly. Furthermore, when viewed with battery electrode materials or metal ions moving between electrodes, lithium ion secondary batteries, sodium ion secondary batteries, nickel metal hydride secondary batteries and the like are not particularly limited and are conventionally known. It can be applied to any electrode material. A lithium ion secondary battery is preferable. The lithium ion secondary battery is suitable for a battery for vehicles that require a high cell voltage and high output. Therefore, a high energy density and a high output density can be achieved, and an excellent battery can be manufactured as a vehicle driving power source. Therefore, in the following description, a polymer lithium ion secondary battery and a bipolar polymer lithium ion secondary battery that are not bipolar type will be described as the lithium ion secondary battery using the electrode of the present invention. It shouldn't be.

  FIG. 7 shows 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 31 shown in FIG. 7, a positive electrode current collector is obtained by using a laminate film in which a polymer-metal is combined with the battery outer packaging material 33 and bonding all the peripheral portions thereof by heat fusion. A positive electrode plate having a positive electrode layer (also referred to as a positive electrode active material layer) 37 formed on both surfaces of the body 35 (one surface for the lowermost layer and the uppermost layer of the power generation element), an electrolyte layer 39, and both surfaces of the negative electrode current collector 41 (power generation It has a configuration in which a power generating element in which a negative electrode plate in which a negative electrode layer (also referred to as a negative electrode active material layer) 43 is formed is housed and sealed is provided on one side for the lowermost layer and the uppermost layer of the element. In addition, the positive electrode (terminal) lead 45 and the negative electrode (terminal) lead 47 that are electrically connected to the electrode plates (positive electrode plate and negative electrode plate) are connected to the positive electrode current collector 35 and the negative electrode current collector 41 of each electrode plate. It is attached by sonic welding, resistance welding, or the like, and has a structure that is sandwiched between the heat fusion parts and exposed to the outside of the battery outer packaging material 33.

  The non-bipolar 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.

  Here, as described above, in the electrode layer (positive electrode layer and negative electrode layer), between the conductive material fine particles in the electrode layer reaches from the surface of the electrode layer to the surface of the current collector in the electrode layer thickness direction. Are connected in contact with each other, and a part of the surface of the electrode active material fine particles in the electrode layer is in contact with the conductive material fine particles. It should not be restricted.

  Therefore, a positive electrode capable of inserting and extracting lithium ions and a negative electrode capable of inserting and extracting lithium ions are used for the electrodes of the polymer lithium ion secondary battery, and a polymer electrolyte is used as an electrolyte layer for power generation elements other than the electrodes. (A gel electrolyte or a solid electrolyte using a gel-like or solid polymer, 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 and negative electrode current collectors that can be used in the present invention are not particularly limited, and conventionally known ones can be used. For example, aluminum foil, stainless steel (SUS) foil, nickel-aluminum clad material, copper-aluminum clad material, SUS-aluminum clad material, or a plated material of a combination of these metals can be preferably used. Further, a current collector in which a metal surface is coated with aluminum may be used. Moreover, you may use the electrical power collector which bonded 2 or more metal foil depending on the case. When a composite current collector is used, examples of the material of the positive electrode current collector include aluminum, aluminum alloy, and SU.
A conductive metal such as S or titanium can be used, but 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 100 μm or less, preferably 1 to 50 μm from the viewpoint of thinning the electrode.

  In the positive electrode layer, a positive electrode active material, a conductive material for increasing electronic conductivity are included, a binder (also referred to as a binder), an electrolyte supporting salt (lithium salt) for increasing ionic conductivity, and an electrolyte. Materials and additives can be included.

  Among these, what constitutes the positive electrode active material part may include a positive electrode active material, a binder (also referred to as a binder), a lithium salt for increasing ion conductivity, an electrolyte material, and the like. On the other hand, what constitutes the conductive material portion may include a conductive material, a binder, and the like for enhancing electronic conductivity. Further, when the polymer electrolyte part is provided separately from the positive electrode active material part, the constituents of the polymer electrolyte part may include an electrolyte material, a lithium salt for increasing ion conductivity, a binder, and the like. .

As said positive electrode active material, the composite oxide (lithium-transition metal composite oxide) of a transition metal and lithium can be used conveniently. 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 by using the Li—Mn-based composite oxide, the profile can be tilted, and the reliability at the time of abnormality is improved. As a result, there is an advantage that the voltage of each single cell layer and the entire bipolar battery can be easily detected. The average particle diameter of the positive electrode active material is as already described.

  Examples of the conductive material include acetylene black, carbon black, graphite, various carbon fibers, and carbon nanotubes. However, it is not necessarily limited to these. The average particle size of the conductive material is also as already described.

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

When a polymer electrolyte is used for the electrolyte layer, it is desirable that the positive electrode layer also contains an electrolyte. This is because by filling the gaps between the positive electrode active material fine particles and the conductive material fine particles in the positive electrode layer with an electrolyte, the ion conduction in the positive electrode layer becomes smooth and the output of the entire bipolar battery can be improved. On the other hand, when a separator is impregnated with a polymer gel electrolyte (including an electrolytic solution) or an electrolytic solution in the electrolyte layer, the positive electrode layer may not contain an electrolyte, and the positive electrode active material fine particles are linked together. What is necessary is just to contain a well-known binder.

The polymer for the polymer solid electrolyte is not particularly limited, and examples thereof include polyethylene oxide (PEO), polypropylene oxide (PPO), and copolymers thereof. Such polyalkylene oxide polymers can well dissolve lithium salts such as LiBF ₄ , LiPF ₆ , LiN (SO ₂ CF ₃ ) ₂ , and LiN (SO ₂ C ₂ F ₅ ) ₂ . Moreover, excellent mechanical strength is exhibited by forming a crosslinked structure. In the present invention, the polymer solid electrolyte is contained in at least one of the positive electrode active material layer and the negative electrode active material layer. However, in order to further improve the battery characteristics of the bipolar battery, it is preferable to be included in both.

Examples of the lithium salt include LiBETI (lithium bis (perfluoroethylenesulfonylimide); also referred to as Li (C ₂ F ₅ SO ₂ ) ₂ N), LiBF ₄ , LiPF ₆ , LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ C ₂ F ₅ ) ₂ , LiBOB (lithium bisoxide borate) or a mixture thereof can be used. However, it is not necessarily limited to these.

  Examples of the electrolyte include an all-solid polymer electrolyte composed only of a polymer electrolyte and a supporting salt such as a lithium salt, and a polymer gel electrolyte in which an electrolyte is held in a polymer. However, these are examples of polymer lithium ion secondary batteries, and are not limited to these.

The all solid polymer electrolyte is not particularly limited, and examples thereof include polyethylene oxide (PEO), polypropylene oxide (PPO), and copolymers thereof. Such a polyalkylene oxide polymer can well dissolve lithium salts such as BETI, LiBF ₄ , LiPF ₆ , LiN (SO ₂ CF ₃ ) ₂ , and LiN (SO ₂ C ₂ F ₅ ) ₂ . Moreover, excellent mechanical strength is exhibited by forming a crosslinked structure.

  As the polymer gel electrolyte, an all-solid polymer electrolyte having ion conductivity containing an electrolyte solution, and further, a polymer (host polymer) skeleton having no lithium ion conductivity. Among them, the one in which a similar electrolytic solution is held is also included.

Here, the electrolyte solution (electrolyte salt and plasticizer) contained in the polymer gel electrolyte may be any one that is usually used in a lithium ion battery. For example, LiBOB (lithium bisoxide borate), LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAsF ₆ , LiTaF ₆ , LiAlCl ₄ , Li ₂ B ₁₀ Cl _{10 and} other inorganic acid anion salts, LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, Li (C ₂ F ₅ SO ₂ ) selected from organic acid anion salts such as 2 _N, wherein at least one lithium salt (electrolyte support salt), propylene carbonate (PC), cyclic carbonates such as ethylene carbonate (EC); dimethyl carbonate, Chain carbonates such as methyl ethyl carbonate and diethyl carbonate; Ethers such as lahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane, 1,2-dibutoxyethane; lactones such as γ-butyrolactone; nitriles such as acetonitrile; methyl propionate, etc. Esters of amides; Amides such as dimethylformamide; Those using an organic solvent (plasticizer) such as an aprotic solvent mixed with at least one selected from methyl acetate and methyl formate Can be used. However, it is not necessarily limited to these.

Examples of the polymer having no lithium ion conductivity used in the polymer gel electrolyte include gels such as polyvinylidene fluoride (PVDF), polyvinyl chloride (PVC), polyacrylonitrile (PAN), and polymethyl methacrylate (PMMA). Monomers that form fluorinated polymers can be used. 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 ratio (mass ratio) between the host polymer and the electrolytic solution in the polymer gel electrolyte may be determined according to the purpose of use, but is in the range of 2:98 to 90:10. That is, electrolyte leakage from the outer peripheral portion of the electrode active material layer can be effectively sealed by providing an insulating layer and an insulating treatment portion. Therefore, it is possible to give priority to battery characteristics relatively with respect to the ratio (mass ratio) between the host polymer and the electrolytic solution in the polymer gel electrolyte.

  Examples of the additive include trifluoropropylene carbonate for enhancing battery performance and life, and various fillers as reinforcing materials.

  In the positive electrode layer, the positive electrode active material, the conductive material, the binder, the electrolyte (host polymer, electrolyte solution, etc.), lithium salt, The amount of components such as additives should be determined in consideration of the purpose of use of the battery (emphasis on output, emphasis on energy, etc.), ion conductivity, and the like. For example, if the blending amount of the polymer electrolyte in the positive electrode layer is too small, the Li ion conduction resistance and the Li ion diffusion resistance in the positive electrode layer are increased, and the battery performance is deteriorated. On the other hand, when the blending amount of the polymer electrolyte in the positive electrode layer is too large, the energy density of the battery is lowered. Therefore, in consideration of these factors, the polymer (gel) electrolytic mass that meets the purpose is determined.

  Since the thickness of the positive electrode layer is as described above, the description thereof is omitted here.

  In addition, in order to form a positive electrode layer, it is desirable to form using the printing application | coating method by each ink as mentioned above. In the present invention, it is more preferable that the film is formed by using an ink jet method.

  In the present invention, in addition to the positive electrode layer, a negative electrode layer, an electrolyte layer, an insulating material, a sealing material, and the like, which will be described later, are more preferably formed using a coating method in which printing is performed by an inkjet method. As described above, this can be formed by arranging an active material or a conductive material at an arbitrary position, and even if it is a complicated and fine arrangement (pattern), it does not impair productivity at all. Since an arrangement (pattern) can be precisely formed, it can be an extremely effective means for forming an electrode layer or the like, for example, when tens to hundreds of single cells are stacked. 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 contains a negative electrode active material, a conductive material for enhancing electronic conductivity (however, when the negative electrode active material is excellent in electronic conductivity such as carbon, etc., it may not be used). In addition, a binder, a lithium salt for increasing ion conductivity, an electrolyte, and the like may be included. Among these, what constitutes the negative electrode active material part may include a negative electrode active material, a binder, a lithium salt for increasing ion conductivity, an electrolyte material, and the like. On the other hand, what constitutes the conductive material portion may include a conductive material, a binder, and the like for enhancing electronic conductivity. Furthermore, when an electrolyte part is provided separately from the negative electrode active material part, the electrolyte part may include an electrolyte material, a lithium salt for increasing ion conductivity, a binder, and the like.

  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.

Examples of the negative electrode active material include various natural graphites and artificial graphites, for example, graphites such as fibrous graphite, scaly graphite, and spherical graphite, and metal compounds, metal oxides, Li metal compounds, Li metal oxides (lithium- Transition metal composite oxide), boron-added carbon and the like. These may be used alone or in combination of two or more. Specifically, 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, Li _0.17 C (LiC ₆ ), and the like. 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. Since the thickness of the negative electrode layer is the same as that of the positive electrode layer, the description thereof is omitted here.

  As the electrolyte layer, (a) a polymer gel electrolyte, (b) a polymer solid electrolyte, or (c) a separator impregnated with these polymer electrolytes or electrolytic solutions (including a nonwoven fabric separator; the same shall apply hereinafter). It can be applied to both. However, these are examples of polymer lithium ion secondary batteries, and in the present invention, a liquid electrolyte is used in which an electrolyte is impregnated in a separator by sealing each electrolyte layer with an insulating layer sealing material. It goes without saying that it can also be done. Regarding (a) the polymer gel electrolyte and (b) the polymer solid electrolyte, since the same electrolyte as that used for the positive electrode layer can be used, the description thereof is omitted here. (C) In the separator impregnated with the polymer electrolyte or the electrolytic solution (electrolyte salt and plasticizer), the electrolyte can be the same as that already described for the electrolyte used for the positive electrode layer. 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 applications such as secondary batteries for driving motors such as electric vehicles (EV) and hybrid electric vehicles (HEV), the thickness of the separator From the viewpoint of thinning, it is desirable that the thickness is 1 to 60 μm in a single layer or multiple layers. 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). Due to the fact that 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. In addition, conventionally known ones can be used. In addition, the fiber used is not particularly limited, and for example, conventionally known fibers such as cotton, rayon, acetate, nylon, polyester, polypropylene, polyethylene such as polyethylene, 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, which may impair the ionic conductivity in the electrolyte layer.

The porosity of the nonwoven fabric separator is preferably 30 to 70%. When the porosity is less than 30%, the electrolyte retention deteriorates, and when it exceeds 70%, the strength is insufficient. Furthermore, the thickness of the nonwoven fabric separator may be the same as that of the electrolyte layer, and is preferably 5 to 20 μm, particularly preferably 5 to 10 μm. If the thickness is less than 5 μm, short-circuit defects increase, and the retention of the electrolyte deteriorates. If the thickness exceeds 20 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 battery, it is preferable to make it as thin as possible as long as the function as an electrolyte can be secured. From this viewpoint, the thickness of the electrolyte layer is 5 to 20 μm, preferably 5 to 10 μm.

  In the present invention, the positive electrode plate and the negative electrode plate are as described in the above-described electrode manufacturing method, and thus the description thereof is omitted here. The electrolyte layer may also be formed using an ink-jet printing method as in the electrode manufacturing method, or may be formed using a coater or the like as in the prior art. The positive and negative electrode plates and the electrolyte layer have the negative electrode active material layer on the upper side of the negative electrode plate opposed to the positive electrode active material layer of the positive electrode plate above the negative electrode plate and the negative electrode active material layer on the lower side of the negative electrode plate. In a state where the electrode is opposed to the positive electrode active material layer of the lower positive electrode plate through the electrolyte layer, these are laminated and integrated by thermal bonding to constitute a laminated electrode (power generation element).

  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 layer formed on one surface of a current collector and a negative electrode layer formed on the other surface are stacked in series with an electrolyte layer interposed therebetween. Take. 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. 8 is a schematic sectional view schematically showing the entire structure of the bipolar polymer battery. As shown in FIG. 8, in the bipolar polymer battery 51, a positive electrode layer (also referred to as a positive electrode active material layer) 55 is provided on one side of a current collector 53 composed of one or more sheets, and the other side is provided. The bipolar electrode 59 provided with the negative electrode layer (also referred to as negative electrode active material layer) 57 of the present invention is configured such that the electrode layers 55 and 57 of the adjacent bipolar electrode 59 sandwich the solid electrolyte layer 61 therebetween. That is, in the bipolar polymer battery 51, a plurality of bipolar electrodes 59 each having the positive electrode layer 55 on one surface of the current collector 53 and the negative electrode layer 57 on the other surface are stacked via the electrolyte layer 61. The electrode laminate (bipolar battery body) 63 having a structure is formed. Further, the uppermost layer and the lowermost layer electrodes 55a and 57a of the electrode laminate 63 in which a plurality of such bipolar electrodes 59 are laminated may not have a bipolar electrode structure, and one side required for the current collector 53 (or terminal plate). Only the electrode layers (the positive electrode active material layer 55a and the negative electrode active material layer 57a) may be arranged. In the bipolar polymer battery 51, positive and negative electrode leads 65 and 67 are joined to current collectors 53 at the upper and lower ends, respectively. The number of stacked bipolar electrodes is adjusted according to the desired voltage. In the bipolar polymer battery 51 of the present invention, since the electrode layer can be made as thin as possible, the number of lamination of the bipolar electrode 59 can be increased from several tens to several hundreds, and sufficient output as a battery can be secured. . In the bipolar polymer battery 51 of the present invention, in order to prevent external impact and environmental degradation during use, the electrode laminate portion is sealed under reduced pressure in a battery exterior material (exterior package) 69, and electrode leads 65, It is preferable that 67 be taken out of the battery exterior material 69. 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 accommodated and sealed (sealed) under reduced pressure by joining a part or all of the peripheral part thereof by heat fusion, and the electrode leads 65 and 67 are taken out of the battery exterior material 69. It is preferable to do this. The basic configuration of the bipolar polymer battery 51 can be said to be a configuration in which a plurality of stacked single battery layers (single cells) are connected in series.

  In addition, regarding the components of the bipolar polymer lithium ion secondary battery, the description of the same components as those of the non-bipolar polymer lithium ion secondary battery is omitted.

  Therefore, the description of the current collector, the positive electrode layer, the negative electrode layer, and the electrolyte layer is omitted.

  The insulating sheet material (insulating layer) used in the bipolar polymer lithium ion secondary battery of the present invention is a short circuit caused by contact between adjacent current collectors in the battery or slight unevenness at the end of the laminated electrode. In the present invention, the outside of the battery current collector is covered (sealed) with a resin group having the function of the insulating layer. Therefore, although it is not necessary to form an insulating layer in particular, the bipolar battery of the present invention does not exclude the embodiment in which the insulating layer is provided around the electrode.

  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. The positive electrode and negative electrode tabs can also be applied to non-bipolar lithium ion secondary batteries.

  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 materials for the positive electrode and the negative electrode tab, for example, aluminum, copper, titanium, nickel, stainless steel (SUS), alloys thereof, and the like 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.

  Regarding the positive electrode and the negative electrode lead, since a known lead used in a normal polymer lithium ion battery which is not the bipolar type described above can be used, description thereof is omitted here.

  Regarding the battery exterior material (battery case), since a known battery exterior material (battery case) used in a normal polymer lithium ion battery that is not the bipolar type described above can be used, description thereof is omitted here.

  Next, as a use of the high output battery of the present invention, for example, as a large-capacity power source for an electric vehicle (EV), a hybrid electric vehicle (HEV), a fuel cell vehicle, a hybrid fuel cell vehicle, etc., high energy density, high output It can be suitably used for a vehicle driving power source (including an auxiliary power source) for which density is required. In this case, it is desirable that the assembled battery is constructed by connecting a plurality of high-power batteries of the present invention. That is, at least one of the high-power batteries of the present invention, in particular, a bipolar polymer lithium ion secondary battery is used, and at least one connection method of parallel connection, series connection, parallel-series connection, and series-parallel connection is used. By using the assembled battery configured as described above, 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 high-power batteries of the present invention are connected in parallel, and N high-power batteries in parallel are further connected in series in a metal or resin battery case. Use batteries. At this time, the number of high-power batteries connected in series / parallel 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 battery packs, and the electrode lead of each high power battery using a lead wire. Moreover, when connecting high power batteries in series / parallel, they may be electrically connected using an appropriate connecting member such as a spacer or a bus bar. 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 can be provided in which the high-power battery and / or the assembled battery is mounted as a driving power source (including an auxiliary power source). The high-power battery and / or the assembled battery of the present invention has various characteristics as described above, and is particularly a compact battery. 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 power 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 running 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 a large in-house space and trunk room can be obtained. 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 depending on the intended use, a high output battery may be mounted without being assembled, or the assembled battery and the high output battery may be mounted in combination. May be. Moreover, as a vehicle in which the high-power 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. It is not a thing.

Hereinafter, the content of the present invention will be described with reference to examples and comparative examples, but the present invention is not limited to these examples. In the following examples, the following materials were used as a positive electrode active material, a negative electrode active material, a conductive material, a polymer electrolyte raw material, a lithium salt, a photopolymerization initiator, and a binder unless otherwise specified.
Positive electrode active material: Spinel type LiMn ₂ O ₄ having an average particle size of 0.6 μm, adjusted to have substantially the same particle size by classification
・ Negative electrode active material: Graphite having an average particle size of 0.7 μm adjusted to have the same particle size by classification after pulverization ・ Conductive material: Secondary particle average adjusted to have substantially the same particle size by classification Acetylene black with a particle size of 0.1 μm / polymer electrolyte raw material: macromer of ethylene oxide and propylene oxide, lithium salt: lithium hexafluorophosphate (LiPF ₆ ) (liquid lithium ion battery) or LiN (SO ₂ C ₂ F ₅ ) ₂ (hereinafter abbreviated as “LiBETI”) (polymer electrolyte battery), photopolymerization initiator: benzyldimethyl ketal (polymer electrolyte battery), binder: polyvinylidene fluoride (PVdF), solvent: N-methyl-2 -Pyrrolidone (NMP)
The polymer electrolyte raw material was synthesized according to the method described in JP-A No. 2002-110239. The preparation, printing, and battery assembly of the negative electrode ink, the positive electrode active material ink, the positive electrode conductive material ink, and the electrolyte ink were performed in a dry atmosphere with a dew point of −30 ° C. or lower. In the following examples, the negative electrode layer uses graphite with high electronic conductivity as the negative electrode active material, so that only the positive electrode layer has the electrode structure of the present invention without using the electrode structure of the present invention.

(Example 1)
A liquid lithium ion battery was prepared according to the following procedure.

<Preparation of negative electrode ink>
A negative electrode active material (9% by mass), PVdF (1% by mass) and NMP (90% by mass) were prepared. 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 active material ink>
A positive electrode active material (7% by mass), PVdF (1% by mass), and NMP (90% by mass) were prepared. These were sufficiently stirred to prepare a slurry as a positive electrode active material ink. The viscosity of this ink was about 4 cP.

<Preparation of positive electrode conductive material ink>
A conductive material (10% by mass) and NMP (90% by mass) were prepared. These were sufficiently stirred to prepare a slurry as a positive electrode conductive material 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 with the following modifications. That is, the parts in the ink introduction part were replaced with metal parts, and ink was supplied directly 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. Since it was difficult to supply the metal foil used as the current collector directly to the printer, the metal foil was attached to A4 quality paper, supplied to the printer, and printed. In this example, printing was performed so that the thickness of the negative electrode layer and the positive electrode layer (after drying) was 5 μm, both of which were not achieved in the past. In accordance with this, the thickness of each current collector was also set to 15 μm, and the size of the current collector was set to the same size as the A4 size fine paper.

First, a negative ink was introduced into a modified ink jet printer, and a pattern created on a computer (in this example, the negative electrode layer was uniformly printed and coated) was used as a negative electrode current collector. Printed on foil. 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.

  Next, a positive electrode active material ink and a positive electrode conductive material ink are separately introduced into a modified ink jet printer, and a pattern created on a computer (in this embodiment, only the positive electrode layer satisfies the constituent requirements of the present invention). Thus, the pattern shown in FIGS. 1 (a) and 1 (b) described above is printed on and applied by an ink jet printer using a positive electrode active material ink and a positive electrode conductive material ink, thereby forming aluminum as a positive electrode current collector. A positive electrode layer was produced on the foil.

  The ratio of the conductive material (acetylene black) in the produced positive electrode layer was 3% by mass as determined from the amount of ink used. 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. When the completed positive electrode was cut and the cross section of the positive electrode layer was observed using an SEM, as shown in FIG. 1A, in each conductive material portion in the positive electrode layer, the conductive material fine particles were separated from the surface of the positive electrode layer. In each positive electrode active material part in the positive electrode layer, only a part of the surface of the positive electrode active material fine particles is electrically connected in the adjacent conductive material part. It was confirmed that the material was in contact with the fine particles.

The produced positive electrode and negative electrode were punched into a circle (diameter 10 mm) and laminated via a polyethylene microporous membrane separator having a thickness of 25 μm to obtain a coin cell. As the electrolytic solution, a mixed solvent of ethylene carbonate (EC) and dimethyl carbonate (DMC) with a volume fraction of 3: 7 containing LiPF ₆ at a concentration of 1 mol / liter was used.

<Evaluation>
The produced battery (coin cell) 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.

(Example 2)
Printing and drying are performed in the same manner as in Example 1 except that the arrangement in the plane direction perpendicular to the electrode layer thickness direction of the positive electrode layer is changed from the pattern of FIG. 1B to the pattern shown in FIG. , Assembled and evaluated.

  The proportion of the conductive material in the positive electrode layer was 3.5% by mass as determined from the amount of ink used. Further, when the completed positive electrode was cut and the cross section of the positive electrode layer was observed, as in Example 1 (see FIG. 1A), in each conductive material portion in the positive electrode layer, the conductive material fine particles were It is connected in a state where it is in contact with the positive electrode layer thickness direction from the positive electrode layer surface to the current collector surface, and in each positive electrode active material part in the positive electrode layer, only a part of the surface of the positive electrode active material fine particles is adjacent to the conductive layer. It was confirmed that the material was in contact with the conductive material fine particles in the material part.

<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)
Printing and drying are performed in the same manner as in Example 1 except that the arrangement in the plane direction perpendicular to the electrode layer thickness direction of the positive electrode layer is changed to the pattern shown in FIG. 3 described above from the pattern in FIG. , Assembled and evaluated.

  The ratio of the conductive material in the positive electrode layer was 4% by mass as determined from the amount of ink used. Further, when the completed positive electrode was cut and the cross section of the positive electrode layer was observed, as in Example 1 (see FIG. 1A), in each conductive material portion in the positive electrode layer, the conductive material fine particles were It is connected in a state where it is in contact with the positive electrode layer thickness direction from the positive electrode layer surface to the current collector surface, and in each positive electrode active material part in the positive electrode layer, only a part of the surface of the positive electrode active material fine particles is adjacent to the conductive layer. It was confirmed that the material was in contact with the conductive material fine particles in the material part.

<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
Printing, drying and assembly in the same manner as in Example 1 except that the arrangement of the positive electrode layer in the plane direction perpendicular to the electrode layer thickness direction is changed from the pattern of FIG. 1B to the pattern shown in FIG. And evaluated.

  The ratio of the conductive material in the positive electrode layer was 5% by mass as determined from the amount of ink used. Further, when the completed positive electrode was cut and the cross section of the positive electrode layer was observed, as in Example 1 (see FIG. 1A), in each conductive material portion in the positive electrode layer, the conductive material fine particles were It is connected in a state where it is in contact with the positive electrode layer thickness direction from the positive electrode layer surface to the current collector surface, and in each positive electrode active material part in the positive electrode layer, only a part of the surface of the positive electrode active material fine particles is adjacent to the conductive layer. It was confirmed that the material was in contact with the conductive material fine particles in the material part.

<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)
Printing, drying and assembly in the same manner as in Example 1 except that the arrangement of the positive electrode layer in the plane direction perpendicular to the electrode layer thickness direction is changed from the pattern of FIG. 1B to the pattern shown in FIG. And evaluated.

  The ratio of the conductive material in the positive electrode layer was 6% by mass as determined from the amount of ink used. Further, when the completed positive electrode was cut and the cross section of the positive electrode layer was observed, as in Example 1 (see FIG. 1A), in each conductive material portion in the positive electrode layer, the conductive material fine particles were It is connected in a state where it is in contact with the positive electrode layer thickness direction from the positive electrode layer surface to the current collector surface, and in each positive electrode active material part in the positive electrode layer, only a part of the surface of the positive electrode active material fine particles is adjacent to the conductive layer. It was confirmed that the material was in contact with the conductive material fine particles in the material part.

<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.

Comparative Example 1 (Example using coating method (conventional method) using a coater, which is difficult due to atomization of the active material)
<Preparation of negative electrode ink>
As the negative electrode active material, graphite (45% by mass), PVdF (5% by mass) and NMP (50% by mass) having an average particle size of 0.7 μm were prepared. These were sufficiently stirred to prepare a slurry as a negative electrode ink.

<Preparation of positive electrode ink>
Spinel type LiMn ₂ O ₄ (40% by mass) having an average particle diameter of 0.6 μm as a positive electrode active material, acetylene black (5% by mass), PVdF (5% by mass) having an average secondary particle diameter of 0.1 μm as a conductive material And NMP (50 mass%) were prepared. These were sufficiently stirred to prepare a slurry as a positive electrode ink.

<Production of battery>
Instead of forming the positive electrode layer and the negative electrode layer by the ink-jet printing method using the negative electrode ink, the positive electrode active material ink, and the positive electrode conductive material ink prepared in Example 1, the positive electrode and the negative electrode prepared in this comparative example Coating, drying, assembly, and evaluation were performed in the same manner as in Example 1 except that the coating method using a conventional coater was performed using ink, that is, the entire coater was coated uniformly.

  The internal resistances of the batteries of Examples 1 to 5 and Comparative Example 1 were measured. FIG. 8 shows the internal resistance ratio with respect to the proportion (mass%) of the conductive material in the positive electrode layer. From the results of FIG. 8, as shown in Examples 1 to 5, it was confirmed that the internal resistance can be reduced by forming the conductive path by arranging the conductive material at an arbitrary position. Here, the internal resistance ratio used here is an electrode printed by the ink jet method of this embodiment when the internal resistance of the battery (coin cell) using the electrode produced by the coating method by the coater of Comparative Example 1 is 1. The ratio of the internal resistance of the battery.

Example 6
For Examples 1 to 5 and Comparative Example 1 which are liquid lithium ion batteries, polymer electrolyte batteries were produced according to the following procedure.

<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 active material ink>
A positive electrode active material (7% by mass) and acetonitrile (85% by mass) as a solvent were prepared. These were sufficiently stirred to prepare a slurry as a positive electrode active material ink. The viscosity of this ink was about 3 cP.

<Preparation of positive electrode conductive material ink>
A conductive material (10% by mass) and acetonitrile (90% by mass) were prepared. These were sufficiently stirred to prepare a slurry as a positive electrode conductive material 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.

  Since it was difficult to supply the metal foil or polymer electrolyte membrane used as a current collector directly to the printer, the metal foil (current collector) and the polymer electrolyte membrane were pasted on the A4 quality paper. These were supplied to a printer and printed. In this example, the negative electrode layer, the polymer electrolyte membrane, and the positive electrode layer were printed so that the thicknesses (after drying) were all 5 μm, which could not be achieved in the past. In accordance with this, the thickness of the current collector was also set to 10 μm, and the size of the current collector was set to the same size as the A4 size fine paper.

  A negative electrode ink was introduced into the modified inkjet printer, and a pattern created on a computer (a pattern for uniformly coating the entire surface) was printed on a stainless steel foil as a current collector. The formed negative electrode layer was uniform and formed without 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 for 20 minutes in a vacuum to obtain a laminate in which the negative electrode layer was laminated on the current collector.

  The electrolyte ink was introduced into the modified ink jet printer, and the electrolyte ink was printed on the negative electrode layer as a pattern that slightly protrudes from the negative electrode layer (as a pattern that uniformly coats the entire surface). The formed polymer electrolyte membrane was uniform and formed without 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 for 20 minutes in a vacuum to obtain a laminate of a current collector, a negative electrode layer, and a polymer electrolyte membrane.

  Similarly, the positive electrode active material ink, the positive electrode conductive material ink, and the electrolyte ink are formed on the polymer electrolyte membrane so that the positive electrode layer formed is slightly smaller than the negative electrode layer. It was printed as follows. 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 collector, a negative electrode layer, a polymer electrolyte membrane, and a positive electrode layer. Furthermore, when the completed laminate was cut and the cross section of the positive electrode layer was observed, in each conductive material portion 12 in the positive electrode layer, the conductive material fine particles were in the positive electrode layer thickness direction from the positive electrode layer surface to the current collector surface. In each positive electrode active material part in the positive electrode layer, only a part of the surface of the positive electrode active material fine particles is connected to the conductive material in the adjacent conductive material part. It was confirmed that it was in contact with the fine particles.

  This laminate was sandwiched between stainless steel foils as a current collector. 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.

FIG. 1A is a schematic cross-sectional view schematically showing one arrangement configuration of the conductive material and the electrode active material of the electrode layer of the present invention applied to the positive electrode layer of Example 1. 1 (b) is a schematic plan view of FIG. 1 (a). It is the cross-sectional schematic which represented typically another arrangement structure of the electrically conductive material and electrode active material of the electrode layer in the electrode for high power batteries of this invention applied to the positive electrode layer of Example 2. FIG. It is the cross-sectional schematic which represented typically the other one arrangement structure of the electrically conductive material and electrode active material of the electrode layer in the electrode for high power batteries of this invention applied to the positive electrode layer of Example 3. FIG. It is the cross-sectional schematic which represented typically the other one arrangement structure of the electroconductive material and electrode active material of the electrode layer in the electrode for high power batteries of this invention applied to the positive electrode layer of Example 4. FIG. FIG. 10 is a schematic cross-sectional view schematically showing another arrangement configuration of the conductive material and the electrode active material of the electrode layer in the high-power battery electrode of the present invention applied to the positive electrode layer of Example 5. FIG. 10 is an explanatory schematic view schematically showing another arrangement configuration of the conductive material and the electrode active material of the electrode layer in the high power battery electrode of the present invention, which is applied to the positive electrode layer of Example 6. 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 using the electrode for high power batteries 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 using the electrode for high power batteries of this invention. The ratio of the conductive material in the positive electrode layer and “the battery using the electrode obtained in Comparative Example 1 having the thickness of the active material having the existing particle size formed by using the coating method by the conventional coater. Ultra-thin high-power battery obtained in Examples 1 to 5 of the present invention, which realizes atomization of an active material formed by using an ink-jet printing method when the internal resistance is 1. It is the graph showing the relationship with the ratio (internal resistance ratio) of the "internal resistance of the battery using the electrode for operation". The electrode for an ultra-thin high-power battery of the present invention that realizes atomization of an active material formed by using an ink-jet printing coating method, and existing particles formed by using a coating method using a conventional coater It is the graph showing the relationship between the ratio of a electrically conductive material, and internal resistance with the electrode which has a diameter active material and is thick.

Explanation of symbols

11 electrode layer, 12 conductive material part,
12a conductive material fine particles, 13a electrode active material fine particles,
13 Active material part, 15 Current collector,
31 Polymer lithium ion secondary battery,
33 battery exterior material, 35 positive electrode current collector,
37 positive electrode layer, 39 electrolyte layer,
41 negative electrode current collector, 43 negative electrode layer,
45 Positive (terminal) lead, 47 Negative (terminal) lead,
51 Bipolar polymer lithium battery,
53 current collector, 55 positive electrode layer,
57 negative electrode layer, 59 bipolar electrode,
61 solid electrolyte layer, 63 electrode laminate (bipolar battery body),
55a, the uppermost positive electrode active material layer of the electrode laminate,
57a, the negative electrode active material layer at the bottom of the electrode laminate,
65 positive lead, 67 ... negative lead,
69 Battery exterior material (exterior package).

Claims (5)

In a battery electrode having a current collector and an electrode layer formed on the current collector,
The conductive material fine particles in the electrode layer are connected in a state where they are in contact with the current collector surface in the electrode layer thickness direction,
A high power battery electrode, wherein a part of the surface of the electrode active material fine particles in the electrode layer is in contact with the conductive material fine particles.   2. The electrode for a high-power battery according to claim 1, wherein an average particle diameter of the electrode active material fine particles is 0.05 to 1 μm.   3. The electrode for an ultra-thin high-power battery according to claim 1, wherein the connection length of the conductive material fine particles is 5 μm or more.   The electrode for a high-power battery according to any one of claims 1 to 3, wherein the electrode layer is formed by a coating method in which printing is performed by an inkjet method.   A high output battery comprising the electrode according to any one of claims 1 to 4.

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