JP5144703B2 - Manufacturing method of all solid state battery - Google Patents

Abstract

A negative-electrode active material layer having an uneven pattern is formed on a surface of a copper foil as a negative-electrode current collector by applying an application liquid by a nozzle-scan coating method (step S102). Subsequently, an application liquid containing a polymer electrolyte material is applied by a spin coating method, thereby forming a solid electrolyte layer in conformity with the uneven pattern (step S103). Subsequently, an application liquid is applied by a doctor blade method, thereby forming a positive-electrode active material layer whose lower surface conforms to the unevenness and whose upper surface is substantially flat (step S104). A thin and high-performance all-solid-state battery can be produced by laminating an aluminum foil as a positive-electrode current collector before the application liquid is cured.

Description

  The present invention relates to a method for manufacturing an all-solid battery.

  For example, as a method of manufacturing a chemical battery such as a lithium ion battery, conventionally, a metal foil as a current collector to which a positive electrode active material and a negative electrode active material are attached is superposed via a separator, and an electrolytic solution is applied to the separator. A technique of impregnating with is known. However, since batteries that contain highly volatile organic solvents as electrolytes need to be handled with care, and further downsizing and higher output are required, in recent years, instead of electrolytes, solid electrolytes have been used. Techniques for manufacturing all solid state batteries by microfabrication have been proposed.

  For example, in Patent Document 1, an active material layer having irregularities on its surface is formed on a metal foil serving as a current collector by an ink jet method, and a solid electrolyte layer and another active material layer are sequentially formed so as to fill the irregularities. A technique for three-dimensionally laminating by an ink jet method is disclosed.

Japanese Patent Laying-Open No. 2005-116248 (for example, paragraph 0029)

  In the technique described in Patent Document 1 described above, a layer in which different functional layers such as a positive and negative active material layer and a solid electrolyte layer formed in one printing process are mixed is laminated in multiple layers by overcoating. The three-dimensional structure is obtained. However, this technique has the following problems.

  First, the ink jet method uses a very small amount of ejected ink, so that it is possible to form a complicated structure as described above with good controllability. However, in order to obtain a desired three-dimensional structure, many times of overcoating are required. Therefore, it takes a long time to manufacture and the productivity is low. Second, separation between functional layers is difficult. In other words, inks containing different materials may be mixed when they come into contact with each other, and the boundary between the functional layers may become unclear, thereby reducing the battery performance. In the technique described in Patent Document 1, drying is performed for each printing process. However, in this way, productivity is further reduced, and mixing between layers formed in each printing process is prevented. Even so, it is not possible to prevent mixing between a plurality of functional layers formed adjacently in one printing process.

  This invention is made | formed in view of the said subject, and it aims at providing the technique which can manufacture the all-solid-state battery which was excellent in performance at low cost with high productivity.

In order to achieve the above object, an all-solid-state battery manufacturing method according to the present invention forms a continuous first active material layer by applying a coating solution containing a first active material on the surface of a substrate substantially flatly. A first active material layer forming step, and a coating liquid containing a second active material having the same polarity as the first active material is discharged from a discharge port provided in a nozzle that moves relative to the surface of the substrate. A second active material layer forming step of forming the second active material layer by applying the coating liquid to the first active material layer in a plurality of lines spaced apart from each other; and the first active material layer on the surface of the substrate. A coating solution containing a polymer electrolyte is applied to the surface of the laminate formed by laminating the active material layer and the second active material layer to form an electrolyte layer having irregularities substantially following the irregularities of the laminate surface. An electrolyte layer forming step, and a third active material having a surface opposite to the first active material on the surface of the electrolyte layer It is characterized in that it comprises a third active material layer forming step of forming a third active material layer by coating a coating solution containing a.

In the invention configured as described above, a continuous first active material layer made of the first active material is formed on the surface of the base material by coating, and a line shape made of the second active material having the same polarity as the first active material. The second active material layer is formed by coating, an electrolyte layer that follows the irregularities of the second active material layer is then formed by coating, and a third active material layer is formed by coating. In this way, the functional layers of the first active material layer, the second active material layer, the electrolyte layer, and the third active material layer are completed in order for each step, so that no overcoating is required and each step is performed. It is simple and the time required for all processes is short. Therefore, it is excellent in productivity. Further, in the second active material layer forming step, the size of the discharge port is appropriately set by discharging the coating liquid containing the second active material from the discharge port of the nozzle that moves relative to the surface of the substrate. By setting to, a second active material layer having a fine pattern with an arbitrary dimension can be formed. According to such a so-called nozzle dispensing method, it is possible to apply a much larger amount of coating liquid in a short time compared to the ink jet method, and to a large area of the base material, it is also three-dimensional. A second active material layer can be formed in a short time.

  In the all solid state battery formed in this way, the continuously formed first active material layer and the line-shaped second active material layer laminated thereon function as a single electrode active material layer. Therefore, a large surface area can be secured as the active material layer of the electrode. In this way, the active material layer having a large surface area and the third active material layer having the opposite polarity are opposed to each other over a wide area via the solid electrolyte layer that follows the unevenness of the second active material layer. In addition, an electrolyte solution containing an organic solvent is not required, and a small size and high output can be obtained. As described above, according to the present invention, it is possible to manufacture an all-solid battery having excellent performance at low cost and with high productivity.

  In the present invention, the second active material may have a specific surface area smaller than that of the first active material. In order to increase the effective surface area of the active material layer and improve the performance as a battery, it is desirable to use particles having a large specific surface area as the active material. On the other hand, since a substance having a large specific surface area has low fluidity, it is difficult to apply a coating solution containing such a substance in a fine pattern. For example, when coating is performed by discharging a coating solution from a fine nozzle, particles having a large specific surface area cause clogging of the nozzle and reduce productivity. For this problem, the first active material having a relatively large specific surface area is continuously formed as a layer, while the second active material having a smaller specific surface area is formed into a line with unevenness to form a good The battery performance can be enhanced by forming an active material layer having a large surface area while obtaining a high productivity.

  Here, the second active material may have the same or substantially the same composition as the first active material. By doing so, the interface between the first active material layer and the second active material layer is substantially eliminated, and both function as a single electrode active material layer. For example, a material having the same composition as the first active material and a smaller specific surface area can be used as the second active material. As a result, the first active material layer has the specific surface area of the first active material itself, and the second active material layer formed in the line-and-space structure has the uneven pattern to serve as the active material layer. The area can be increased.

  In this case, in the first active material layer forming step, the nozzle that has a discharge port having a larger opening area than the discharge port of the nozzle that discharges the coating liquid containing the second active material and moves relative to the surface of the substrate. The coating liquid containing the first active material may be discharged from the discharge port. Various known coating methods can be applied as a method for forming the first active material layer by coating, but a continuous coating layer can also be obtained by moving a nozzle that discharges the coating solution relative to the substrate. Can be formed. In this case, by using a nozzle having a discharge opening with a large opening area, even a coating liquid containing an active material with a large specific surface area can be applied without clogging.

  On the other hand, in the third active material layer forming step, a coating liquid containing the third active material may be applied by a knife coating method, a doctor blade method, a bar coating method or a slit coating method. In the third active material layer, the surface on the side in contact with the electrolyte layer needs to have an uneven shape that follows the unevenness, while the surface on the opposite side does not have to be uneven as well. Rather it is desirable to be flat. This is because it is necessary to form a current collector layer on the third active material layer. Therefore, the above-described method is preferable as a coating method capable of finishing the surface on the opposite side of the surface in contact with the electrolyte layer in a fine manner while the coating liquid spreads in detail corresponding to the uneven shape.

  In addition, when the coating liquid applied in the third active material layer forming step is in an uncured state, a current collector for superimposing a conductive film serving as a current collector corresponding to the third active material on the layer of the coating liquid You may further provide a body lamination process. By doing so, the third active material layer and the current collector are in close contact with each other, and the current collector can efficiently collect current.

  In the present invention, it is preferable that the thickness of the electrolyte layer is made thinner than the height difference of the unevenness of the second active material layer. In order to obtain a high-performance battery, it is desirable that the first and second active material layers and the third active material layer are arranged in a wide area and as close as possible. Here, if the electrolyte layer is formed thick, the significance of providing the uneven second active material layer in order to increase the surface area is destroyed, and the distance from the third active material layer is also increased. Therefore, it is desirable that the thickness of the electrolyte layer is thinner than at least the uneven height difference of the second active material layer.

  According to the all solid production method of the present invention, the surface area of the one active material layer is increased by forming the line-shaped second active material layer on the continuous first active material layer, and the electrolyte layer, Since the all-solid battery is manufactured by sequentially applying the three active material layers, it is possible to manufacture an all-solid battery having excellent performance at low cost and with high productivity.

It is a figure which shows schematic structure of a lithium ion battery module. It is a flowchart which shows the module manufacturing method in this embodiment. It is a figure which shows typically the mode of the 1st active material coating liquid application | coating by a knife coat method. It is a figure which shows typically the mode of the 1st active material coating liquid application | coating by a nozzle scan method. It is a figure which shows typically the mode of the 2nd negative electrode active material application | coating by a nozzle scan method. It is a figure which shows typically the mode of material application | coating by a spin coat method. It is a figure which shows typically the mode of positive electrode active material application | coating by a knife coat method.

  FIG. 1 is a diagram showing a schematic structure of a lithium ion battery module. More specifically, FIG. 1A is a perspective view schematically showing a lithium ion battery module 1 as an example of an all-solid battery manufactured by the manufacturing method according to the present invention. FIG. 1B is a diagram showing a cross-sectional structure of the battery module 1. The lithium ion battery module 1 includes a first negative electrode active material layer 12a that is substantially flat and continuous on a negative electrode current collector 11, and a second negative electrode active material layer formed in a plurality of line patterns spaced apart from each other. 12b, the solid electrolyte layer 13, the positive electrode active material layer 14, and the positive electrode collector 15 are laminated | stacked in order. In this specification, the X, Y, and Z coordinate directions are defined as shown in FIG.

  As will be described in detail later, the second negative electrode active material layer 12b has a line-and-space structure in which a large number of linear patterns extending along the Y direction are arranged at regular intervals in the X direction. On the other hand, the solid electrolyte layer 13 is a continuous thin film formed of a solid electrolyte and having a substantially constant thickness, and the negative electrode active material layers 12a and 12b are formed on the negative electrode current collector 11 as described above. Almost the entire top surface of the laminate is uniformly covered so as to follow the irregularities on the surface of the laminate.

  Moreover, the lower surface side of the positive electrode active material layer 14 has an uneven structure along the unevenness of the upper surface of the solid electrolyte layer 13, but the upper surface is substantially flat. And the positive electrode collector 15 is laminated | stacked on the upper surface of the positive electrode active material layer 14 formed in this substantially flat shape, and the lithium ion battery module 1 is formed. The lithium ion battery module 1 is appropriately provided with a tab electrode, or a plurality of modules are stacked to constitute a lithium ion battery.

Here, as a material constituting each layer, a known material as a constituent material of the lithium ion battery can be used. As the positive electrode current collector 15 and the negative electrode current collector 11, for example, an aluminum foil or a copper foil is used. Each can be used. As the positive electrode active material may be, for example, LiCoO ₂ (lithium cobaltate), LiMnO ₂ (lithium manganese oxide) and mixtures thereof. As the negative electrode active material, for example, a mixture of Li ₄ Ti ₅ O ₁₂ (lithium titanate) and graphite can be used. Further, as the solid electrolyte layer 13, for example, a borate ester polymer electrolyte can be used. The material of each functional layer is not limited to these.

  The lithium ion battery module 1 having such a structure is thin and easy to bend. In addition, since the negative electrode active material layers 12a and 12b have a three-dimensional structure having irregularities as illustrated, the surface area with respect to the volume is increased, so that the surface area facing the positive electrode active material layer 14 via the thin solid electrolyte layer 13 is increased. Can be made large, and high efficiency and high output can be obtained. Thus, the lithium ion battery having the above-described structure is small and can obtain high performance.

  Next, a method for manufacturing the above-described lithium ion battery module 1 will be described. Conventionally, this type of module has been formed by laminating thin film materials corresponding to each functional layer. However, this manufacturing method has a limit in increasing the density of the module. Moreover, in the manufacturing method of above-mentioned patent document 1, there are many processes, it takes time for manufacture, and isolation | separation between each functional layer is difficult. On the other hand, in the manufacturing method described below, the lithium ion battery module 1 having the above-described structure can be manufactured with a small number of steps and using an existing processing apparatus.

  FIG. 2 is a flowchart showing the module manufacturing method in this embodiment. In this manufacturing method, first, a metal foil, such as a copper foil, to be the negative electrode current collector 11 is prepared (step S101). Since thin copper foils are difficult to transport and handle, it is preferable to improve transportability, for example, by attaching one side to a carrier such as a glass plate.

Subsequently, a first active material coating liquid containing a first negative electrode active material is applied to one surface of the copper foil by an appropriate application method, for example, a knife coating method (step S102). The “first negative electrode active material” is a particulate negative electrode active material having the composition exemplified above, and has a relatively large specific surface area of the particles. For example, lithium titanate having a specific surface area of 10 to 20 m ² / g or more is preferable. The particle diameter is preferably about 1 to 7 μm, but may be larger, for example, 10 to 20 μm or more. As the coating liquid, in addition to the first negative electrode active material, for example, acetylene black as a conductive auxiliary agent, polyvinylidene fluoride (PVDF) as a binder, N-methylpyrrolidone (NMP) as a solvent, and the like. A mixture can be used.

  FIG. 3 is a diagram schematically showing the state of applying the first active material coating solution by the knife coating method. A coating apparatus (knife coater) for applying a coating liquid by a knife coating method is configured to be movable in the X direction, and discharge nozzle 21 that discharges the first active material coating liquid, and the coating liquid discharged from the discharge nozzle 21 Is provided with a knife-like blade 22 for leveling the negative electrode current collector 11 along the surface of the negative electrode current collector 11 and a moving mechanism 24 for horizontally moving a support block 23 supporting the blade 22 in the Y direction. When the discharge nozzle 21 moving in the X direction discharges the first active material coating liquid onto the negative electrode current collector 11, the blade 22 whose lower end is supported with a predetermined gap from the surface of the negative electrode current collector 11 is supported as a support block. The coating liquid is leveled on the negative electrode current collector 11 by moving horizontally in the Y direction by the operation of the moving mechanism 24 together with 23, and a thin and uniform first negative electrode active material on the upper surface of the negative electrode current collector 11 A laminate is formed by forming the layer 12a. As the knife coater, for example, the one described in JP-A-07-289973 can be used.

  In addition, about the method of forming the 1st negative electrode active material layer 12a, it is not limited to the above-mentioned knife coat method, For example, a doctor blade method may be used. In addition to this, it is possible to apply various known coating apparatuses suitable for forming a thin and smooth film, such as a curtain coater, a fountain coater (die coater), a bar coater, and a spin coater. Moreover, as shown below, it is good also by the application | coating using the nozzle dispensing method, especially the nozzle scan method which moves the nozzle which discharges a coating liquid, and a coating target object relatively.

  FIG. 4 is a diagram schematically showing the state of the application of the first active material coating solution by the nozzle scanning method. In the application by the nozzle scan method, the discharge nozzle 27 that continuously discharges the first active material application liquid is reciprocally scanned in the Y direction on the negative electrode current collector 11, and the position is gradually changed in the X direction for each scan. I will change it. At this time, the feed pitch of the discharge nozzles 27 in the X direction is made substantially equal to the width of the coating liquid 28 discharged from the discharge nozzles 27. The discharge port diameter of the discharge nozzle 27 can be, for example, about 0.2 to 1 mm. This also makes it possible to form the first active material layer 12 a on almost the entire surface of the negative electrode current collector 11.

  In the application by the nozzle scanning method, periodic irregularities corresponding to the nozzle feed pitch appear on the upper surface of the first active material layer 12a obtained by the application depending on the viscosity and the scanning speed of the application liquid. There is. This is not a demerit in the present embodiment, but rather has the following advantages.

  That is, as described above, the lithium ion battery module 1 manufactured by the manufacturing method of this embodiment includes the first negative electrode active material layer 12a and the second negative electrode active material layer 12b formed later by coating. It functions as a negative electrode active material layer as a whole, and its surface performance is increased by complicating the surface shape and increasing the surface area. As described above, if the upper surface of the first negative electrode active material layer 12a has a concavo-convex structure, the surface shape becomes more complicated, and the surface area of the negative electrode active material layer can be increased to improve performance.

  Thus, the laminated body 100 by which the 1st negative electrode active material layer 12a is formed in the upper surface of the copper foil 11 which is a negative electrode collector by hardening the coating liquid apply | coated by the appropriate method by drying or baking. Composed. Alternatively, a photo-curable resin may be added to the coating solution and cured by light irradiation after coating. The thickness of the first negative electrode active material layer 12a thus formed is suitably about 50 to 100 μm.

  By forming an active material layer 12a by applying an active material having a large specific surface area, the effective surface area of the active material layer 12a can be increased, and the performance as a battery can be improved. However, a coating liquid containing particles having a large specific surface area is likely to cause clogging of the nozzle 21 or 27 because the fluidity of the particles is low. In order to prevent this, it is desirable to set the nozzle outlet diameter in consideration of the specific surface area and particle diameter of the active material. For example, it is preferable to set it to at least about 10 times the particle diameter of the negative electrode active material. In addition, it is desirable to reduce the viscosity of the coating solution (for example, 5 to 10 Pa · s) so that the discharged solution spreads uniformly on the copper foil 11.

Returning to the flowchart of FIG. 2, the description of the module manufacturing method in this embodiment will be continued. Subsequently, a second active material coating liquid containing a second negative electrode active material is applied to the upper surface of the active material layer 12a thus formed by a nozzle scan method (step S103). The “second negative electrode active material” has the same composition as the first negative electrode active material described above, but has a smaller specific surface area of the particles. For example, lithium titanate having a specific surface area of about 1 to 5 m ² / g can be used. Moreover, as a particle diameter suitable for the continuous discharge from a micro nozzle, the thing of 1-7 micrometers is preferable. The components other than the active material may be the same as the first active material coating solution, but may be a coating solution having a higher viscosity (for example, 50 to 100 Pa · s). Since particles having a smaller specific surface area tend to have lower viscosity at the same concentration, the viscosity can be appropriately adjusted by reducing the solvent component.

  FIG. 5 is a diagram schematically showing the state of application of the second negative electrode active material by the nozzle scanning method. More specifically, FIG. 5 (a) is a view of the state of application by the nozzle scanning method as viewed from the X direction, and FIGS. 5 (b) and 5 (c) are views of the same state as viewed from the Y direction and obliquely from above. It is. The nozzle 31 used in this step has a structure in which a large number of discharge ports 311 having an opening area smaller than that of the nozzle 21 (FIG. 3) or 27 (FIG. 4) from which the first active material coating solution is discharged are arranged in the X direction. Have. The dimension of the discharge port 311 is desirably about 10 times the particle diameter of the second negative electrode active material, that is, about 10 to 70 μm. The negative active material layer 12a formed on the copper foil 11 is obtained by moving the nozzle 31 for discharging the second active material coating liquid 32 in the arrow direction Dn2 relative to the laminate 100. The coating is applied in a line shape spaced apart from each other in the X direction and extending along the Y direction. A laminate in which a second negative electrode active material layer 12b in a line shape is formed on a substantially flat first negative electrode active material layer 12a by curing the second active material coating liquid by drying, baking or light irradiation. 101 is formed.

  The second negative electrode active material contained in the second active material coating liquid has high fluidity because the specific surface area of the particles is small, and does not clog the discharge port 311 having a small opening area. In addition, by using a high-viscosity coating liquid, the spread of the coating liquid after ejection is reduced, and a concavo-convex pattern having a high ratio of height to width in the cross section, that is, an aspect ratio can be formed. As typical dimensions of the second negative electrode active material layer 12b, for example, the width and height of each line and the space between the lines can all be about 20 to 100 μm.

  At this time, the substantially flat first negative electrode active material layer 12a and the second negative electrode active material layer 12b having a concavo-convex pattern are raised with respect to the surface of the substantially flat copper foil 11, and are substantially the same. The first and second negative electrode active material layers 12a and 12b having the composition function as a negative electrode active material layer as a unit. In this case, compared to an active material layer having a flat top surface, the surface area relative to the amount of active material used can be greatly increased. Can be obtained. Further, in the flat first negative electrode active material layer 12a, the surface area is increased by applying particles having a large specific surface area, while in the second negative electrode active material layer 12b, particles having a small specific surface area are used. The surface area can be increased by forming an uneven pattern while preventing clogging.

Returning to FIG. 2 again, the description of the flowchart will be continued. An electrolyte coating solution is applied to the upper surface of the laminate 101 formed in this way, for example, by spin coating (step S104). As the electrolyte coating solution, a mixture of the above-described polymer electrolyte material, for example, a resin such as polyethylene oxide or polystyrene, for example, LiPF ₆ (lithium hexafluorophosphate) as a supporting salt, and, for example, diethylene carbonate as a solvent, etc. Can be used.

  FIG. 6 is a diagram schematically showing the state of material application by spin coating. A laminate 101 formed by laminating the first and second negative electrode active material layers 12a and 12b on the copper foil 11 is a rotary stage 42 that is rotatable around a rotation axis in the vertical direction (Z direction) in a predetermined rotation direction Dr. Placed substantially horizontally. Then, the rotation stage 42 rotates at a predetermined rotation speed, and the coating solution 43 containing the polymer electrolyte material is discharged toward the laminated body 101 from the nozzle 41 provided at the upper position on the rotation axis of the rotation stage 42. . The coating liquid dropped on the laminate 101 spreads around by centrifugal force, and excess liquid is shaken off from the end of the laminate 101. By doing so, the upper surface of the laminated body 101 is covered with a thin and uniform coating solution, and the solid electrolyte layer 13 is formed by curing this. In the spin coating method, the film thickness can be controlled by the viscosity of the coating solution and the rotation speed of the rotary stage 42, and the unevenness is also applied to the object having a concavo-convex structure on the surface such as the laminate 101. There is also a sufficient track record in forming a thin film with a uniform thickness.

  The thickness of the solid electrolyte layer 13 is arbitrary, but it is necessary that the positive and negative active material layers be reliably separated and that the internal resistance be less than an allowable value. For example, it can be set to 20 to 50 μm. From the viewpoint of not destroying the significance of the unevenness of the negative electrode active material layer 12b provided to increase the surface area, the thickness of the solid electrolyte layer 13 (symbol t13 in FIG. 1B) is the negative electrode active material layer. It is desirable that it is thinner than the height difference of the irregularities of 12b (symbol t12 in FIG. 1B).

  The description of the flowchart of FIG. 2 will be continued. For the laminate formed by laminating the copper foil 11, the negative electrode active material layers 12a and 12b, and the solid electrolyte layer 13 thus formed, an appropriate method, for example, a knife used for forming the first active material layer 12a. A coating solution containing a positive electrode active material is applied by a coating method to form the positive electrode active material layer 14 (step S105). As the coating solution, for example, a mixture of the positive electrode active material and the above-described conductive additive, binder, solvent, and the like can be used.

  FIG. 7 is a diagram schematically showing a state of applying the positive electrode active material by the knife coating method. When the coating liquid containing the positive electrode active material is discharged from the nozzle (not shown) onto the surface of the laminate, the blade 52 moves the upper surface of the laminate in the arrow direction Dn3 with its lower end in contact with the coating liquid. Thereby, the upper surface of the coating liquid 54 is leveled flat.

  In this way, by applying the coating liquid 54 containing the positive electrode active material to the laminate 102 while leveling with the blade 52, the lower surface has irregularities along the irregularities of the solid electrolyte layer 13, while the upper surface is substantially flat. An active material layer 14 is formed on a laminate 102 formed by laminating a negative electrode current collector 11, first and second negative electrode active material layers 12 a and 12 b, and a solid electrolytic layer 13. The thickness of the positive electrode active material layer 14 is suitably 20 to 100 μm, which is about the same as that of the second negative electrode active material layer 12b.

  Returning to FIG. 2, a metal foil, for example, an aluminum foil, which becomes the positive electrode current collector 15 is laminated on the upper surface of the positive electrode active material layer 14 thus formed (step S106). At this time, it is desirable to overlap the positive electrode current collector 15 on the upper surface of the positive electrode active material layer 14 formed in the previous step S105 before it is cured. By doing so, the positive electrode active material layer 14 and the positive electrode current collector 15 can be bonded to each other and bonded together. Moreover, since the upper surface of the positive electrode active material layer 14 is leveled, it is easy to stack the positive electrode current collector 15 without any gap. As described above, the lithium ion battery module 1 shown in FIG. 1A can be manufactured.

  As described above, in this embodiment, the first active material coating liquid is applied to the entire upper surface of the negative electrode current collector 11 to form the substantially flat negative electrode active material layer 12a, and then the linear negative electrode active material layer 12b. Is formed by a nozzle dispensing method. And the electrolyte coating liquid is apply | coated on it, the solid electrolyte layer 13 is formed, and the positive electrode active material coating liquid is apply | coated on it, and the positive electrode active material layer 14 is formed. Thus, since the coating liquid used as the material of each functional layer is piled up in order, the number of processes is small, and the lithium ion battery module 1 can be manufactured with high productivity in a short time.

  Since the first and second active material layers 12a and 12b have substantially the same composition, they function as a negative electrode active material layer having a large surface area as a whole. Here, in the flat first negative electrode active material layer 12a, particles having a large specific surface area are used to increase the surface area, while in the second negative electrode active material layer 12b, a large number of lines are arranged. The surface area is increased by the fine uneven pattern formed by. For the first active material coating liquid containing particles having a large specific surface area, the nozzle 21 or 27 having a discharge opening having a large opening area, and for the second active material coating liquid containing particles having a small specific surface area, the discharge port 311 having a small opening area. In each case, the negative electrode active material layer having a high productivity and a large surface area can be formed without causing clogging of the nozzles.

  Here, since the application by the nozzle dispensing method is applied to the formation of the negative electrode active material layer 12b that needs to form the uneven pattern, various patterns can be formed in a short time. Also, the nozzle dispensing method can be suitably applied to the creation of a fine pattern. In this manufacturing method, it is only necessary to create the fine pattern only in the application process of the second active material coating solution, and if the application can be performed uniformly in the subsequent application process, it is not necessary to create a fine pattern. .

  The solid electrolyte layer 13 is desirably a thin and uniform film following the irregularities on the upper surfaces of the negative electrode active material layers 12a and 12b. Therefore, the spin coating method is applied for the formation. According to the spin coating method, it is possible to form a thin and uniform film in a short time by dropping the coating liquid 43 while rotating the laminate 101 that is the object to be processed.

  Further, regarding the positive electrode active material layer 14, it is desirable that the lower surface follows the unevenness and the upper surface is flat. Therefore, the object is achieved by applying a knife coating method in which the coating liquid 54 is leveled by the blade 52. Moreover, before the coating liquid 54 applied in this way is cured, the positive electrode active material layer 14 and the positive electrode current collector 15 formed by curing the coating liquid 54 are overlapped by overlapping the aluminum foil that becomes the positive electrode current collector 15. It can be adhered without gaps.

  The lithium ion battery thus formed is thin and easy to bend, and the positive electrode active material and the negative electrode active material face each other over a wide area through a thin solid electrolyte layer, so that high output can be obtained. It is.

  As described above, in this embodiment, the copper foil as the negative electrode current collector 11 corresponds to the “base material” of the present invention. The first negative electrode active material having a large specific surface area among the negative electrode active materials corresponds to the “first active material” of the present invention, and the first negative electrode active material layer 12a is the “first active material layer” of the present invention. Is equivalent to. Therefore, step S102 in FIG. 2 corresponds to the “first active material layer forming step” of the present invention.

  Further, in this embodiment, the second negative electrode active material having a small specific surface area corresponds to the “second active material” of the present invention, and the second negative electrode active material layer 12b is the “second active material layer” of the present invention. Is equivalent to. Therefore, step S103 in FIG. 2 corresponds to the “second active material layer forming step” of the present invention.

  The solid electrolyte layer 13 corresponds to the “electrolyte layer” of the present invention, and step S104 in FIG. 2 corresponds to the “electrolyte layer forming step” of the present invention. Further, the positive electrode active material and the positive electrode active material layer 14 correspond to the “third active material” and the “third active material layer” of the present invention, and step S105 of FIG. This corresponds to the “layer formation step”. Further, the aluminum foil as the positive electrode current collector 15 corresponds to the “conductive film” of the present invention, and step S106 in FIG. 2 corresponds to the “current collector stacking process” of the present invention.

  The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention. For example, in the above embodiment, particles having a large specific surface area are used as the first active material and particles having a smaller specific surface area are used as the second active material. However, the present invention is not limited to this. The substances may be the same.

  For example, the coating method applied in each step is not limited to the above, and other coating methods may be applied as long as they meet the purpose of the step. For example, in the above-described embodiment, the spin coating method is applied to form the solid electrolyte layer 13, but any other method can be used as long as it can form a thin film that follows the unevenness of the surface to be coated. For example, a coating solution containing a polymer electrolyte may be applied by a spray coating method.

  Further, for example, in the above embodiment, the knife coating method or the nozzle dispensing method is used to form the first negative electrode active material layer 12a, but the present invention is not limited to this. That is, since the first negative electrode active material layer 12a may be formed uniformly on the entire surface of the copper foil 11, it may be applied using another known method such as a spin coating method.

  In addition, the first negative electrode active material layer 12a is desirably formed so as to continuously cover almost the entire surface of the base material (copper foil 11), that is, so that the surface of the base material is not exposed. It is not a requirement. Therefore, you may form the 1st negative electrode active material layer 12a itself in the surface shape which has a concavo-convex pattern more positively. By doing so, it is possible to further increase the surface area of the negative electrode active material layer formed by integrating the first and second negative electrode active material layers. Here, in the case where the first negative electrode active material layer 12a is formed into a line-shaped uneven pattern, if the extending direction and the arrangement pitch are different from those of the second negative electrode active material layer 12b, the negative electrode active as a whole will be described. The surface shape of the material layer becomes more complicated, and the surface area can be increased.

  Further, for example, in the above embodiment, the knife coating method is applied to form the positive electrode active material layer 14, but the lower surface in contact with the surface to be coated follows the unevenness, and the upper surface can be finished substantially flat. Any other application method may be used as long as it is possible. In order to achieve such an object, it is desirable that the viscosity of the coating solution is not so high. In other words, if the viscosity of the coating solution is appropriately selected, the lower surface may be uneven and the upper surface may be omitted by other coating methods. It is possible to finish it flat, and it may be applied by each of the application methods mentioned as suitable application methods for forming the first negative electrode active material layer 12a.

  In the above embodiment, the negative electrode active material layer, the solid electrolyte layer, the positive electrode active material layer, and the positive electrode current collector are sequentially laminated on the negative electrode current collector. On the contrary, on the positive electrode current collector, The positive electrode active material layer, the solid electrolyte layer, the negative electrode active material layer, and the negative electrode current collector may be laminated in this order. In the above embodiment, the negative electrode active material layer has a two-layer structure of particles having different specific surface areas, but the positive electrode active material layer may have such a two-layer structure.

  Further, the materials such as the current collector, active material, and electrolyte exemplified in the above embodiment are only examples, and are not limited thereto, and other materials used as a constituent material of the lithium ion battery are used. Even in the case of manufacturing a lithium ion battery, the manufacturing method of the present invention can be preferably applied. Further, the present invention is not limited to the lithium ion battery, and the present invention can be applied to the manufacture of all chemical batteries (all solid batteries) using other materials.

  The present invention can be suitably applied to an all-solid battery manufacturing technology, and is particularly suitable for manufacturing a low-cost, small-sized, high-power battery with excellent productivity.

11 Negative electrode current collector (base material)
12a First negative electrode active material layer (first active material layer)
12b Second negative electrode active material layer (second active material layer)
13 Solid electrolyte layer (electrolyte layer)
14 Positive electrode active material layer (third active material layer)
15 Positive electrode current collector (conductive film)
S102 1st active material layer formation process S103 2nd active material layer formation process S104 Electrolyte layer formation process S105 3rd active material layer formation process S106 Current collector lamination process

Claims (7)

A first active material layer forming step of forming a continuous first active material layer by applying a coating solution containing a first active material on a surface of a substrate substantially flatly ;
Said from a discharge port formed in a nozzle moves relative to the surface of the substrate by discharging a coating solution containing a second active material of the first active material and the electrode, the said first active material layer A second active material layer forming step of forming a second active material layer by applying the coating liquid in a plurality of lines separated from each other;
A coating solution containing a polymer electrolyte is applied to the surface of a laminate formed by laminating the first active material layer and the second active material layer on the surface of the base material, and substantially follows the irregularities on the surface of the laminate. An electrolyte layer forming step of forming an electrolyte layer having irregularities formed,
A third active material layer forming step of forming a third active material layer by applying a coating liquid containing a third active material opposite to the first active material on the surface of the electrolyte layer. A method for producing an all-solid battery.   The method for producing an all solid state battery according to claim 1, wherein the second active material has a specific surface area smaller than a specific surface area of the first active material.   The manufacturing method of the all-solid-state battery of Claim 1 or 2 which coat | covers the coating liquid containing a said 2nd active material, after hardening the coating liquid containing a said 1st active material. The second active material, method for manufacturing the all-solid-state cell according to any one of claims 1 to 3 having the first active material and the same or substantially the same composition. In the first active material layer forming step, the first active material is applied from the discharge port of the nozzle that has a discharge port having a larger opening area than the discharge port of the nozzle and moves relative to the surface of the substrate. The manufacturing method of the all-solid-state battery in any one of Claim 1 thru | or 4 which discharges a liquid.   When the coating liquid applied in the third active material layer forming step is in an uncured state, a current collector for superimposing a conductive film serving as a current collector corresponding to the third active material on the layer of the coating liquid The manufacturing method of the all-solid-state battery in any one of Claim 1 thru | or 5 further provided with a body lamination process.   The manufacturing method of the all-solid-state battery in any one of Claim 1 thru | or 6 which makes thickness of the said electrolyte layer thinner than the height difference of the unevenness | corrugation of the said 2nd active material layer.

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