Battery electrode manufacturing device and battery electrode manufacturing method

Abstract

To improve the quality of an active material layer in a battery.SOLUTION: A battery electrode manufacturing device includes a supply unit that supplies an electrode composition containing an active material to a substrate film being transported, a pressing unit that compresses the electrode composition formed on the substrate film, an inspection unit that irradiates the substrate film and the electrode composition with X-rays and performs inspection using the X-rays, and a control unit that performs processing according to results obtained by the inspection unit.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a battery electrode manufacturing apparatus and a battery electrode manufacturing method. [Background technology]

[0002] Lithium ion batteries are high-capacity secondary batteries that have been used in a variety of applications in recent years. An electrode for a lithium ion battery is composed of an active material layer, a current collector layer, a separator, and a frame that encapsulates the active material layer (see, for example, Patent Document 1). The active material layer in a lithium ion battery can be formed, for example, by supplying an electrode composition to a strip-shaped substrate film and compressing it using a roll press or the like.

[0003] Although the active material layer is preferably formed with a uniform density, variations in density may occur due to various factors. For example, when an electrode composition on a substrate film is compressed by a roll press or the like, cracks may occur in the electrode composition, and the cracks may remain in the active material layer. Furthermore, for example, when the electrode composition is supplied to the substrate film, the supply amount may be reduced in some areas, causing depressions or cavities, which may result in variations in density in the active material layer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6633866 [Patent Document 2] Patent No. 3355097 [Patent Document 3] Patent No. 3680985 Summary of the Invention [Problem to be solved by the invention]

[0005] It is preferable to detect defects such as cracks, dents, and cavities during the manufacturing process and take appropriate measures when defects are detected. For example, it is preferable to take appropriate measures to improve the quality of the active material layer in the battery, such as rejecting the product as defective or adjusting the manufacturing method to reduce the risk of defects. For example, Patent Document 2 describes measuring the thickness of the active material applied to the electrode plate core material and feedback-controlling the shape of the doctor blade to adjust the amount of active material applied. Furthermore, Patent Document 3 describes monitoring the coating thickness of an electrode active material paste material applied to the current collector sheet surface after coating and drying, and coating the material using feedback control. However, even when measuring the thickness of the active material, some types of defects, such as cracks and cavities, cannot be detected.

[0006] The present invention has been made in consideration of the above circumstances, and aims to provide a battery electrode manufacturing apparatus and a battery electrode manufacturing method that can improve the quality of the active material layer in a battery. [Means for solving the problem]

[0007] In order to achieve the above object, the battery electrode manufacturing apparatus of the present invention comprises a supply unit that supplies an electrode composition containing an active material to a substrate film being transported, a pressure unit that compresses the electrode composition formed on the substrate film, an inspection unit that irradiates the substrate film and the electrode composition with X-rays and performs inspection using the X-rays, and a control unit that performs processing according to the results obtained by the inspection unit. [Effects of the Invention]

[0008] According to the battery electrode manufacturing apparatus and battery electrode manufacturing method of the present invention, the quality of the active material layer in the battery can be improved. [Brief explanation of the drawings]

[0009] [Figure 1]FIG. 1 is a cross-sectional view of a single cell of a battery manufactured using the battery electrode manufacturing apparatus of the embodiment. [Figure 2] FIG. 2 is a schematic diagram of a battery electrode manufacturing apparatus according to an embodiment. [Figure 3] FIG. 3 is a diagram showing an example of the configuration of an electrode composition supplying device according to an embodiment. [Figure 4] FIG. 4 is a diagram for explaining depressions formed in the electrode composition of the embodiment and their detection. [Figure 5] FIG. 5 is a diagram for explaining cavities generated in the electrode composition of the embodiment and their detection. [Figure 6A] FIG. 6A is a diagram for explaining the process performed by the replenishing device according to the embodiment. [Figure 6B] FIG. 6B is a diagram for explaining the process performed by the replenishing device according to the embodiment. [Figure 7] FIG. 7 is a diagram for explaining cracks that occur in the electrode composition of the embodiment and how to detect the cracks.

[0010] (First embodiment) Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the drawings used in the following description may show characteristic portions enlarged for the purpose of emphasizing the characteristic portions, and the dimensional ratios of the components may not be the same as in reality. Also, for the same purpose, some parts may be omitted in the drawings.

[0011] <Battery pack (secondary battery)> The battery electrode manufacturing apparatus and battery electrode manufacturing method according to the first embodiment are applied to the manufacture of lithium ion batteries, for example. Lithium ion batteries are used in the form of a modularized battery assembly formed by combining a plurality of lithium ion single cells (also referred to as single cells or battery cells), or in the form of a battery pack formed by combining a plurality of such battery assemblies and adjusting the voltage and capacity. While the following describes an example of a lithium ion secondary battery, the type of secondary battery according to the present invention is not limited to a lithium ion secondary battery and includes other secondary batteries.

[0012] <Single cell (battery cell)> 1 is a cross-sectional view of a single cell 10. The above-described battery pack can be produced by combining a plurality of single cells 10. For example, the single cell 10 has two electrodes 20 (battery electrodes), a positive electrode 20a and a negative electrode 20b, and a separator 30.

[0013] The separator 30 is disposed between the positive electrode 20a and the negative electrode 20b. In the assembled battery, the plurality of unit cells 10 are stacked with the positive electrode 20a and the negative electrode 20b facing in the same direction.

[0014] The separator 30 holds an electrolyte. As a result, the separator 30 functions as an electrolyte layer. The separator 30 is disposed between the electrode active material layers 22 of the positive electrode 20a and the negative electrode 20b, and prevents them from contacting each other. As a result, the separator 30 functions as a partition wall between the positive electrode 20a and the negative electrode 20b.

[0015] Examples of the electrolyte held in the separator 30 include an electrolytic solution or a gel polymer electrolyte. The use of these electrolytes ensures high lithium ion conductivity. Examples of the separator form include a porous sheet separator made of a polymer or fiber that absorbs and holds the electrolyte, and a nonwoven fabric separator.

[0016] The positive electrode 20a and the negative electrode 20b each have a current collector 21, an electrode active material layer 22, and a frame 35. The electrode active material layer 22 and the current collector 21 are arranged in this order from the separator 30 side. The frame 35 is frame-shaped (annular). The frame 35 surrounds the periphery of the electrode active material layer 22. The frame 35 of the positive electrode 20a and the frame 35 of the negative electrode 20b are welded to each other and integrated. Alternatively, the frame 35 of the positive electrode 20a and the frame 35 of the negative electrode 20b may be integrally fabricated from the beginning. That is, the frame 35 of the positive electrode 20a and the frame 35 of the negative electrode 20b may be fabricated separately and then integrated, or may be fabricated as a single member. In the following description, when it is necessary to distinguish between the electrode active material layers 22 of the positive electrode 20a and the negative electrode 20b, they will be referred to as the positive electrode active material layer 22a and the negative electrode active material layer 22b, respectively.

[0017] <Specific examples of positive electrode current collectors> The positive electrode current collector constituting the positive electrode current collector layer 21a can be a current collector used in known lithium-ion cells, such as a known metal current collector or a resin current collector composed of a conductive material and a resin (such as the resin current collectors described in JP 2012-150905 A and WO 2015 / 005116 A). From the viewpoint of battery characteristics, etc., the positive electrode current collector constituting the positive electrode current collector layer 21a is preferably a resin current collector.

[0018] Examples of metal current collectors include one or more metal materials selected from the group consisting of copper, aluminum, titanium, nickel, tantalum, niobium, hafnium, zirconium, zinc, tungsten, bismuth, antimony, alloys containing one or more of these metals, and stainless steel alloys. These metal materials may be used in the form of a thin plate, metal foil, or the like. Alternatively, the metal current collector may be formed by forming the above-mentioned metal material on the surface of a substrate made of a metal other than the above-mentioned metal materials by a method such as sputtering, electrodeposition, or coating.

[0019] The resin current collector preferably contains a conductive filler and a matrix resin. Examples of the matrix resin include, but are not limited to, polyethylene (PE), polypropylene (PP), and polymethylpentene (PMP). The conductive filler is not particularly limited as long as it is selected from materials having electrical conductivity. The conductive filler may be in the form of a fibrous conductive fiber.

[0020] The resin current collector may contain, in addition to the matrix resin and the conductive filler, other components (such as a dispersant, a crosslinking accelerator, a crosslinking agent, a colorant, an ultraviolet absorber, and a plasticizer). Furthermore, a plurality of resin current collectors may be stacked, or a resin current collector and a metal foil may be stacked.

[0021] The thickness of the positive electrode current collector layer 21a is not particularly limited, but is preferably 5 to 150 μm. When a plurality of resin current collectors are stacked to form the positive electrode current collector layer 21a, the total thickness after stacking is preferably 5 to 150 μm. The positive electrode current collector layer 21a can be obtained, for example, by melt-kneading a matrix resin, a conductive filler, and an optional filler dispersant to obtain a conductive resin composition, and then molding the resulting composition into a film using a known method.

[0022] <Specific examples of positive electrode active materials> The positive electrode active material layer 22a is preferably a non-binding mixture containing a positive electrode active material. Here, "non-binding" means that the positions of the positive electrode active materials in the positive electrode active material layer are not fixed, and the positive electrode active materials are not irreversibly fixed to each other. When the positive electrode active material layer 22a is a non-binding layer, the positive electrode active materials are not irreversibly fixed to each other, allowing separation without mechanical destruction of the interfaces between the positive electrode active materials. Even when stress is applied to the positive electrode active material layer 22a, the positive electrode active material moves, preventing destruction of the positive electrode active material layer 22a. The non-binding positive electrode active material layer 22a can be obtained by, for example, converting the positive electrode active material layer 22a into a positive electrode active material layer 22a containing a positive electrode active material and an electrolyte solution but not containing a binder. In this specification, "binder" refers to an agent that cannot reversibly fix the positive electrode active materials to each other or to the current collector. Such binders are used by dissolving or dispersing them in a solvent, and when the solvent is evaporated or distilled away, the surface solidifies without exhibiting any adhesiveness, and therefore cannot reversibly fix the positive electrode active materials together or the positive electrode active material to the current collector.

[0023] Examples of the positive electrode active material include, but are not limited to, composite oxides of lithium and transition metals, composite oxides containing two types of transition metal elements, and composite oxides containing three or more types of metal elements.

[0024] The positive electrode active material may be a coated positive electrode active material in which at least a portion of the surface thereof is coated with a coating material containing a polymer compound. When the periphery of the positive electrode active material is coated with a coating material, volume change of the positive electrode is alleviated, and expansion of the positive electrode can be suppressed.

[0025] As the polymer compound constituting the coating material, those described as resins for coating active materials in JP 2017-054703 A and WO 2015 / 005117 A, etc., can be suitably used.

[0026] The coating material may contain a conductive agent, which may be the same as the conductive filler contained in the positive electrode current collector layer 21a.

[0027] The positive electrode active material layer 22a may contain an adhesive resin. Examples of suitable adhesive resins include those described in JP 2017-054703 A, in which a small amount of organic solvent is mixed with a nonaqueous secondary battery active material coating resin to adjust its glass transition temperature below room temperature, and those described in JP 10-255805 A as adhesives. The adhesive resin refers to a resin that remains tacky even after drying by volatilizing the solvent components and remains tacky (i.e., adheres by application of slight pressure without using water, solvents, heat, etc.). On the other hand, a solution-drying electrode binder used as a binder refers to a material that dries and solidifies by volatilizing the solvent components, thereby firmly adhering and fixing active materials together. Therefore, the binder (solution-drying electrode binder) and the adhesive resin are different materials.

[0028] The positive electrode active material layer 22a may contain an electrolytic solution containing an electrolyte and a non-aqueous solvent. The electrolyte may be any of those used in known electrolytic solutions. The non-aqueous solvent may be any of those used in known electrolytic solutions. For example, a mixed solution of ethylene carbonate (EC) and dimethyl carbonate (DMC), or a mixed solution of ethylene carbonate (EC) and propylene carbonate (PC) may be used.

[0029] The positive electrode active material layer 22a may contain a conductive additive, which may be a conductive material similar to the conductive filler contained in the positive electrode current collector layer 21a.

[0030] The thickness of the positive electrode active material layer 22a is not particularly limited, but from the viewpoint of battery performance, it is preferably 100 to 700 μm, and more preferably 200 to 500 μm.

[0031] In this embodiment, the positive electrode composition supplied to form the positive electrode active material layer 22a is a wet powder containing a positive electrode active material and a nonaqueous electrolyte. The wet powder is preferably in a pendular or funicular state. Alternatively, the positive electrode composition may be a clay-like (semi-solid) positive electrode active material kneaded with an electrolyte.

[0032] The proportion of the non-aqueous electrolyte in the wet powder is not particularly limited, but in order to achieve a pendular or funicular state, in the case of a positive electrode, it is desirable that the proportion of the non-aqueous electrolyte be 0.20 to 40% by weight of the entire wet powder.

[0033] <Specific examples of negative electrode current collectors> The negative electrode current collector constituting the negative electrode current collector layer 21b can be appropriately selected from the same configuration as that described for the positive electrode current collector and can be obtained by the same method. From the viewpoint of battery characteristics, the negative electrode current collector layer 21b is preferably a resin current collector. The thickness of the negative electrode current collector layer 21b is not particularly limited, but is preferably 5 to 150 μm.

[0034] <Specific examples of negative electrode active materials> The negative electrode active material layer 22b is preferably a non-binding mixture containing a negative electrode active material. The reasons why the negative electrode active material layer is preferably a non-binding material and the method for obtaining the non-binding negative electrode active material layer 22b are the same as the reasons why the positive electrode active material layer 22a is preferably a non-binding material and the method for obtaining the non-binding positive electrode active material layer 22a.

[0035] The negative electrode active material may be, for example, a carbon-based material, a silicon-based material, or a mixture thereof, but is not particularly limited thereto.

[0036] The negative electrode active material may be a coated negative electrode active material in which at least a portion of the surface thereof is coated with a coating material containing a polymer compound. When the periphery of the negative electrode active material is coated with the coating material, volume change of the negative electrode is alleviated, and expansion of the negative electrode can be suppressed.

[0037] As the coating material, the same coating material as that constituting the coated positive electrode active material can be suitably used.

[0038] The negative electrode active material layer 22b contains an electrolytic solution containing an electrolyte and a non-aqueous solvent. The composition of the electrolytic solution can be preferably the same as that of the electrolytic solution contained in the positive electrode active material layer 22a.

[0039] The negative electrode active material layer 22b may contain a conductive additive, which may suitably be the same conductive material as that contained in the positive electrode active material layer 22a.

[0040] The negative electrode active material layer 22b may contain an adhesive resin, which may be the same as the adhesive resin that is an optional component of the positive electrode active material layer 22a.

[0041] The thickness of the negative electrode active material layer 22b is not particularly limited, but from the viewpoint of battery performance, it is preferably 100 to 700 μm, and more preferably 200 to 500 μm.

[0042] In this embodiment, the negative electrode composition supplied to form the negative electrode active material layer 22b is a wet powder containing a negative electrode active material and a nonaqueous electrolyte. The wet powder is preferably in a pendular or funicular state. Alternatively, the negative electrode composition may be a clay-like (semi-solid) negative electrode active material kneaded with an electrolyte.

[0043] The proportion of the non-aqueous electrolyte in the wet powder is not particularly limited, but in order to achieve a pendular or funicular state, in the case of a negative electrode, it is desirable that the proportion of the non-aqueous electrolyte be 0.20 to 40% by weight of the entire wet powder.

[0044] <Examples of separators> Examples of the electrolyte held in the separator 30 include an electrolytic solution and a gel polymer electrolyte. The use of these electrolytes ensures high lithium ion conductivity in the separator 30. The form of the separator 30 is, for example, a porous film made of polyethylene or polypropylene, but is not particularly limited thereto.

[0045] <Example of frame body> The frame 35 is not particularly limited as long as it is a material that is durable against the electrolyte, but for example, a polymer material is preferred, and a thermoplastic polymer material is more preferred. The material constituting the frame 35 may be any material that has insulating properties, sealing properties (liquid-tightness), heat resistance at battery operating temperatures, electrolyte resistance, etc., and a resin material is preferably used. More specifically, the frame 35 may be made of, for example, a polyolefin resin, a polyurethane resin, or a polyvinylidene fluoride resin, with polyolefin resin being preferred because of its high durability and ease of handling.

[0046] <Battery electrode manufacturing device and battery electrode manufacturing method> Next, a battery electrode manufacturing apparatus and a battery electrode manufacturing method (hereinafter simply referred to as manufacturing method) according to this embodiment will be described. For example, in the battery electrode manufacturing apparatus and the battery electrode manufacturing method, a positive electrode 20a and a negative electrode 20b are first manufactured. The manufacturing methods of the positive electrode 20a and the negative electrode 20b differ mainly in the electrode active material contained in the electrode active material layer 22. Here, the manufacturing methods of the positive electrode 20a and the negative electrode 20b will be collectively described as the manufacturing method of the electrode 20.

[0047] 2 is a schematic diagram of a battery electrode manufacturing apparatus 1000. For example, the battery electrode manufacturing apparatus 1000 includes a chamber 110, a conveying device 120, a control device 130, an electrode composition supplying device 140, a thickness measuring device 150, an X-ray generator 161, an X-ray detector 162, a replenishing device 170, a pressing device 180, a thickness measuring device 190, an X-ray generator 201, and an X-ray detector 202. Note that the following description will be given as an example in which the strip-shaped substrate film is a strip-shaped current collector 21B. The current collector 21B is, for example, a resin current collector.

[0048] The chamber 110 is a room whose interior can be maintained at a pressure lower than atmospheric pressure. The interior of the chamber 110 is reduced in pressure to a pressure lower than atmospheric pressure by a vacuum pump (not shown). Note that standard atmospheric pressure is approximately 1013 hPa (approximately 101 kPa).

[0049] For example, a current collector roll 21R is disposed outside the chamber 110, and a strip-shaped current collector 21B pulled out from the current collector roll 21R is transported into the chamber 110 through a slit. Hereinafter, the strip-shaped current collector 21B may be referred to as a current collector 21B. The current collector 21B is the current collector 21 described above before it is cut into a predetermined shape. The current collector 21B is transported at a predetermined speed by a transport device 120. The space outside the chamber 110 in which the current collector roll 21R is disposed may be at normal pressure, or may be reduced in pressure by a chamber different from the chamber 110.

[0050] In the following description, the transport direction in which current collector 21B is transported is referred to as the X direction, and the vertical direction is referred to as the Y direction. More specifically, the downstream side of the transport direction of current collector 21B corresponds to the +X direction, and the upstream side corresponds to the -X direction. Furthermore, the upper side in the vertical direction corresponds to the +Y direction, and the lower side corresponds to the -Y direction. When current collector 21B is transported horizontally, the X direction and the Y direction are perpendicular to each other. The Z direction, which is perpendicular to the X direction and the Y direction, corresponds to the width direction of current collector 21B.

[0051] The conveying device 120 conveys the current collector 21B in the +X direction. For example, the conveying device 120 is a belt conveyor that supports the current collector 21B from below. After the electrode composition 22c described below is supplied, the conveying device 120 conveys the current collector 21B carrying the electrode composition 22c. After the frame 35 described below is supplied, the conveying device 120 conveys the frame 35 and the current collector 21B carrying the electrode composition 22c. The conveying device 120 is an example of a conveying section.

[0052] The control device 130 is connected to the electrode composition supply device 140, thickness measurement device 150, X-ray generator 161, X-ray detector 162, replenishment device 170, press device 180, thickness measurement device 190, X-ray generator 201, and X-ray detector 202 via a network and controls these devices. While the specific configuration of the control device 130 is not particularly limited, for example, the control device 130 includes a processing circuit such as a CPU (Central Processing Unit) or an ASIC (Application Specific Integrated Circuit), and the processing circuit executes a predetermined program to control various devices. Although FIG. 2 illustrates a single control device 130, the control device 130 may be realized by combining multiple devices. For example, a control device 130 that controls the electrode composition supply device 140 and a control device 130 that controls the thickness measurement device 150 may be provided separately. The control device 130 is an example of an inspection unit and an example of a control unit. For example, the control device 130 irradiates an electrode having a current collector 21B and an electrode composition 22c with X-rays, performs an inspection using the X-rays, and further performs processing according to the results obtained by performing the inspection.

[0053] The electrode composition supplying device 140 is a device that supplies the electrode composition 22c to the current collector 21B transported by the transporting device 120. The electrode composition supplying device 140 is an example of a supplying section. Note that the combination of the current collector 21B and the electrode composition 22c is also simply referred to as an electrode, regardless of whether it is compressed by the pressing device 180 or not.

[0054] An example of the configuration of the electrode composition supply device 140 is shown in FIG. 3. For example, the electrode composition supply device 140 includes a wall member 143, a wall member 144, a roller 145, and a shutter 146. The wall member 143 and the wall member 144 form a hopper that holds the electrode composition 22c in its internal space. The shutter 146 opens and closes an opening at the bottom of the hopper, thereby achieving intermittent supply of the electrode composition 22c to the current collector 21B. That is, the electrode composition 22c is supplied while the opening is open, and the supply of the electrode composition 22c is stopped while the opening is closed. As a result, the electrode composition 22c is intermittently supplied onto the current collector 21B, as shown in FIG. 2, for example. The electrode composition 22c supplied onto the current collector 21B is compressed by the roller 145. For example, the roller 145 is a leveling roller that applies pressure sufficient to flatten the surface of the electrode composition 22c.

[0055] The amount of electrode composition 22c held in the hopper formed by wall member 143 and wall member 144 is controlled by hopper 141 and screw conveyor 142. Specifically, screw conveyor 142 supplies electrode composition 22c held in hopper 141 to the hopper formed by wall member 143 and wall member 144 while stirring it. This makes it possible to maintain the amount of electrode composition 22c held in the hopper formed by wall member 143 and wall member 144 while suppressing sticking of electrode composition 22c.

[0056] 3 is merely one example, and various modifications are possible. For example, one or both of the wall members 143 and 144 may be formed of a moving belt. In this case, by driving the moving belt, a downward force is applied to the electrode composition 22c in the hopper, thereby enabling the electrode composition 22c to be supplied more smoothly.

[0057] The thickness measuring device 150 is a device that measures the thickness of the electrode composition 22c on the current collector 21B. For example, the thickness measuring device 150 is a distance sensor that uses a laser or the like, and is disposed above (at a position on the +Y direction side of) the electrode composition 22c to be measured. Here, the current collector 21B is held at a constant height by the conveying device 120, and the lower surface (the surface on the -Y direction side) of the electrode composition 22c is in contact with the current collector 21B, so the height of the lower surface of the electrode composition 22c is known. Therefore, by measuring the height of the upper surface (the surface on the +Y direction side) of the electrode composition 22c with the thickness measuring device 150, the distance from the upper surface to the lower surface of the electrode composition 22c (i.e., the thickness) can be measured.

[0058] Similarly, thickness measuring device 190 is a device that measures the thickness of electrode composition 22c on current collector 21B. Thickness measuring device 150 measures the thickness of electrode composition 22c before it is compressed by press device 180, and thickness measuring device 190 measures the thickness of electrode composition 22c after it has been compressed by press device 180. Processing that is performed based on the measurement results by thickness measuring device 150 and thickness measuring device 190 will be described later.

[0059] The X-ray generator 161 is a device that generates X-rays for inspecting the electrode composition 22c on the current collector 21B. For example, the X-ray generator 161 is an X-ray tube that irradiates X-rays onto the electrode having the current collector 21B and the electrode composition 22c. The X-ray detector 162 is a device that detects X-rays that have passed through the current collector 21B and the electrode composition 22c. That is, the X-ray detector 162 performs inspection using the X-rays irradiated from the X-ray generator 161. For example, the X-ray detector 162 is an X-ray flat panel detector (FPD). Alternatively, the X-ray detector 162 may be a line sensor in which detecting elements are arranged in the width direction (Z direction). The control device 130 can use the X-ray generator 161 and the X-ray detector 162 to inspect the electrode composition 22c before it is compressed by the press device 180. X-ray generator 161 is an example of an X-ray irradiation unit, and X-ray detector 162 is an example of an X-ray detection unit. For example, as shown in Fig. 2, X-ray generator 161 is disposed on one side of an electrode having current collector 21B and electrode composition 22c, and X-ray detector 162 is disposed on the other side of the electrode.

[0060] Similarly, the control device 130 can use the X-ray generator 201 and the X-ray detector 202 to inspect the electrode composition 22c after it has been compressed by the press device 180. The X-ray generator 201 is an example of an X-ray irradiation unit, and the X-ray detector 202 is an example of an X-ray detection unit. Processing that is performed based on the results of the inspection using the X-ray generator 161, the X-ray detector 162, the X-ray generator 201, and the X-ray detector 202 will be described later.

[0061] The press device 180 compresses the electrode composition 22c supplied to the current collector 21B. For example, as shown in FIG. 2, the press device 180 has an upper roller 181 and a lower roller 182. The press device 180 sandwiches and compresses the electrode composition 22c supplied to the current collector 21B between the upper roller 181 and the lower roller 182. That is, the press device 180 performs roll pressing on the electrode composition 22c.

[0062] When performing the roll press, a release film may be used to prevent the electrode composition 22c from adhering to the roller. For example, a rolled release film is pulled out in synchronization with the conveyance speed of the electrode composition 22c and placed on top of the electrode composition 22c before the roll press. By performing the roll press with the release film sandwiched between the upper roller 181 and the electrode composition 22c, adhesion of the electrode composition 22c to the upper roller 181 is prevented. After the roll press, the release film is peeled off from the electrode composition 22c and can be collected, for example, by being wound up in a roll.

[0063] Although not shown in FIG. 2 , the battery electrode manufacturing apparatus 1000 may further include a frame supplying device. The frame supplying device supplies a frame 35 to the current collector 21B being transported. For example, the frame supplying device may have a robot arm and place a pre-manufactured frame 35 at a predetermined position on the current collector 21B being transported. Alternatively, the frame supplying device may manufacture the frame 35 on the current collector 21B. For example, the current collector 21B is used as a base material, and a predetermined material is ejected or applied in a predetermined shape onto the current collector 21B using a dispenser, a coater, or the like, to form the frame 35 on the current collector 21B.

[0064] As described above, the battery electrode manufacturing apparatus 1000 of Fig. 2 can manufacture electrodes such as the positive electrode 20a and the negative electrode 20b. Furthermore, the unit cell 10 can be manufactured by stacking the positive electrode 20a and the negative electrode 20b with the separator 30 sandwiched therebetween. The step of stacking the positive electrode 20a and the negative electrode 20b with the separator 30 sandwiched therebetween may be performed by the battery electrode manufacturing apparatus 1000, or may be performed by an apparatus different from the battery electrode manufacturing apparatus 1000.

[0065] For example, the battery electrode manufacturing apparatus 1000 manufactures the positive electrode 20a and the negative electrode 20b by performing the various steps described with reference to FIG. 2. Next, the battery electrode manufacturing apparatus 1000 supplies a separator 30 to the surface of the positive electrode 20a facing the positive electrode active material layer 22a, and then supplies the negative electrode 20b so that the separator 30 and the negative electrode active material layer 22b are in contact with each other, thereby manufacturing a single cell 10. Alternatively, the battery electrode manufacturing apparatus 1000 supplies a separator 30 to the surface of the negative electrode 20b facing the negative electrode active material layer 22b, and then supplies the positive electrode 20a so that the separator 30 and the positive electrode active material layer 22a are in contact with each other, thereby manufacturing a single cell 10. The separator 30 may be supplied continuously to the current collector 21B and the electrode composition 22c being transported along the transport direction (X direction), or may be supplied sheet by sheet after dividing the current collector 21B and the electrode composition 22c into predetermined units.

[0066] The electrode active material layer 22 in the positive electrode 20a and the negative electrode 20b manufactured by the battery electrode manufacturing apparatus 1000 preferably has a uniform density. However, due to various factors, defects may occur in the electrode composition 22c on the current collector 21B, resulting in variations in the density of the electrode active material layer 22. Furthermore, even if defects do not occur, the amount of electrode composition 22c supplied to the current collector 21B may be partially or entirely less or more. The amount of electrode composition 22c supplied to the current collector 21B is also referred to as basis weight. If the basis weight differs from the target value, the density of the electrode composition 22c after compression will also differ from the target value.

[0067] For example, when the electrode composition supply device 140 supplies the electrode composition 22c to the current collector 21B, the supply amount may be reduced in some areas, resulting in depressions as shown in FIG. 4. Although the electrode composition supply device 140 controls the electrode composition 22c applied to the current collector 21B to a constant thickness, it is not easy to control the behavior of the electrode composition 22c. Furthermore, when the electrode composition 22c is a wet powder, its tendency to solidify under pressure makes it particularly difficult to control its behavior. For this reason, even when the electrode composition 22c is supplied under appropriate conditions, there may be cases where the supply amount is reduced in some areas. Note that although depressions can be removed visually by compressing the electrode composition 22c using a press device 180, the areas where the depressions were present will have a lower density than other areas.

[0068] 4 can be detected based on the measurement results obtained by the thickness measurement device 150, for example, and appropriate measures can be taken. For example, the control device 130 can supply additional electrode composition 22c from a replenishing device 170, which will be described later, to the electrode composition 22c in which a dent has been detected to make up for the dent. Furthermore, for example, the control device 130 can remove the electrode composition 22c in which a dent has been detected from the production line as a defective product.

[0069] Defects in the electrode composition 22c do not only appear on the surface, such as dents, but can also occur internally. For example, when the electrode composition supply device 140 supplies the electrode composition 22c to the current collector 21B, if the supply amount is reduced in a certain area, a cavity as shown in Figure 5 may occur. Note that the cavity can be filled by compressing it with the press device 180, but the area where the cavity was located will have a lower density than the other areas.

[0070] Such internal cavities are difficult to detect based on the measurement results obtained by the thickness measurement device 150, but in the battery electrode manufacturing device 1000, the cavities can be detected from the results of an inspection using the X-ray generator 161 and the X-ray detector 162. When the current collector 21B is a resin current collector, X-rays are less obstructed by the current collector 21B, and therefore, X-ray inspection of the electrode composition 22c can be performed with high accuracy.

[0071] For example, the control device 130 causes the X-ray generator 161 to irradiate pulsed X-rays at the timing when the transported electrode composition 22c is positioned directly below the X-ray generator 161. The X-rays irradiated from the X-ray generator 161 pass through the electrode composition 22c and the current collector 21B and are detected by each pixel (detection element) of the X-ray detector 162. The X-ray detector 162 outputs a detection signal corresponding to the detected X-ray dose to the control device 130, and the control device 130 generates an X-ray image I1 using the detection signal. For example, the control device 130 performs current-to-voltage conversion, A / D conversion, parallel-to-serial conversion, etc. on the detection signal received from the X-ray detector 162 to generate the X-ray image I1 shown in FIG. 5.

[0072] The control device 130 then analyzes the X-ray image I1 to detect defects such as cavities. For example, the control device 130 compares the pixel value of each pixel in the X-ray image I1 with a threshold value and identifies a group of pixels whose pixel values ​​exceed the threshold value as defects. The defect detection process by the control device 130 may be performed using AI (Artificial Intelligence). For example, a machine learning model that is functional to detect defects based on image input is generated in advance, and the control device 130 detects defects such as cavities by inputting the X-ray image I1 into the machine learning model. Cavities may be tolerated if they are minute, and the control device 130 may learn the relationship between the cavities and the inspection results in a subsequent process to determine whether the product is good. Specific examples of the machine learning model are not particularly limited, and any classifier or discriminator such as a neural network, a support vector machine, or a random forest may be used.

[0073] 5, an example in which defects are detected by analyzing the X-ray image I1 has been described, but the embodiment is not limited to this. For example, the control device 130 may omit generating the X-ray image I1 and detect defects based on detection signals received from the X-ray detector 162. For example, the control device 130 can detect defects by comparing the detection signals with a threshold value.

[0074] As with dents, if a cavity is detected, appropriate measures can be taken. For example, the control device 130 can supply additional electrode composition 22c' from the replenishing device 170 to fill the cavity in the electrode composition 22c in which a cavity has been detected. Also, for example, the control device 130 can remove the electrode composition 22c in which a cavity has been detected from the production line as a defective product.

[0075] The replenishment process by the replenishment device 170 will be described with reference to Figures 6A and 6B. In summary, as shown in Figure 6A, when a depression is detected from the measurement results by the thickness measurement device 150 or a cavity is detected from the inspection results using the X-ray generator 161 and the X-ray detector 162, the replenishment device 170 supplies additional electrode composition 22c to the position where the depression or cavity is detected. Note that, hereinafter, the additional electrode composition 22c supplied from the replenishment device 170 will also be referred to as electrode composition 22c' in order to distinguish it from the electrode composition 22c on the current collector 21B.

[0076] 6B, the replenishing device 170 includes a hopper 171, a screw conveyor 172, and a geared motor 173. The hopper 171 holds the electrode composition 22c therein. The screw conveyor 172 receives a driving force from the geared motor 173 to transport the electrode composition 22c in the hopper 171 and supplies additional electrode composition 22c' onto the electrode composition 22c on the current collector 21B.

[0077] More specifically, the screw conveyor 172 shown in FIG. 6B has six lines arranged along the width direction (Z direction). The replenishing device 170 has six lines, which allows it to adjust the supply position in the Z direction, and adjust the supply timing to adjust the supply position in the X direction. That is, the replenishing device 170 supplies additional electrode composition 22c' from a line whose Z coordinate coincides with the position where a depression or cavity is detected, at a timing when the X coordinate of the discharge port of that line coincides with the position where the depression or cavity is detected. Note that FIG. 6B is merely an example, and various modifications are possible to the specific configuration of the replenishing device 170. For example, the discharge port for supplying the additional electrode composition 22c' may be configured to be movable at least in the width direction (Z direction), and the position of the discharge port may be aligned with the coordinate where the depression or cavity is detected to supply the additional electrode composition 22c'. As one example, the replenishing device 170 uses a robot arm having a discharge head at its tip that holds the electrode composition 22c' to align the position of the discharge outlet with the coordinates where the depression or cavity has been detected and supplies additional electrode composition 22c'. As another example, the replenishing device 170 is provided with a rail that extends in the width direction, and by running the discharge head that holds the electrode composition 22c' on the rail, the replenishing device 170 aligns the position of the discharge outlet with the coordinates where the depression or cavity has been detected and supplies additional electrode composition 22c'.

[0078] As described above, the replenishing device 170 can supply additional electrode composition 22c' to any position on the XZ plane corresponding to the detected depression or cavity. Note that, as shown in Figures 6A and 6B, the upper surface of the electrode composition 22c is partially raised by the amount of the additional electrode composition 22c' supplied, but the upper surface of the electrode composition 22c can be flattened by later compressing it with the pressing device 180.

[0079] The thickness measuring device 190 measures the thickness of the electrode composition 22c after compression by the press device 180. For example, the control device 130 can control the compression conditions in the press device 180 based on the measurement results by the thickness measuring device 190. That is, the control device 130 can feed back the measurement results by the thickness measuring device 190 to the compression conditions in the press device 180. For example, if the thickness of the electrode composition 22c after compression deviates from the target value, the control device 130 adjusts the roll gap and press pressure to eliminate the deviation.

[0080] Furthermore, when compression is performed by the press device 180, a portion of the electrode composition 22c may adhere to the upper roller 181. In this case, a dent is formed on the upper surface of the electrode composition 22c as shown in Fig. 4. If a dent is detected in the compressed electrode composition 22c, the control device 130 can take appropriate action, such as removing the electrode composition 22c from the production line as a defective product.

[0081] 7 may occur inside the electrode composition 22c when compressed by the press device 180. Such cracks are difficult to detect based on the measurement results of the thickness measurement device 190, but in the battery electrode manufacturing apparatus 1000, cracks can be detected from the results of an inspection using the X-ray generator 201 and the X-ray detector 202.

[0082] For example, the control device 130 causes the X-ray generator 201 to irradiate pulsed X-rays at a timing when the transported electrode composition 22c is positioned directly below the X-ray generator 201, thereby generating an X-ray image I2 shown in FIG. 7. The control device 130 then analyzes the X-ray image I2 to detect cracks. Alternatively, the control device 130 may omit generating the X-ray image I2 and detect defects based on the detection signal received from the X-ray detector 202.

[0083] Here, the control device 130 can control the compression conditions in the press device 180 according to the results of detecting cracks in the compressed electrode composition 22c. That is, the control device 130 can feed back the results of the inspection using the X-ray generator 201 and the X-ray detector 202 to the compression conditions in the press device 180. For example, if the frequency of cracks is high, the control device 130 can change the compression conditions to suppress the frequency of cracks, such as by changing the press speed or changing the press gap within the range of non-defective product specifications. Furthermore, electrode compositions 22c in which cracks are detected can be treated appropriately, such as by being removed from the production line as defective products.

[0084] It should be noted that cracks do not necessarily occur during compression by the press device 180, but may occur due to other factors. For example, cracks may occur when the electrode composition 22c is supplied to the current collector 21B by the electrode composition supply device 140 shown in FIG. 3 or when compression is performed by the roller 145. In such cases, it is not appropriate to change the compression conditions in the press device 180.

[0085] Whether or not a crack occurred during compression by the press device 180 can be determined based on the results of detecting cracks in the electrode composition 22c before compression and the results of detecting cracks in the electrode composition 22c after compression. For example, if a crack does not appear in an X-ray image collected using the X-ray generator 161 and the X-ray detector 162, but a crack appears in an X-ray image collected using the X-ray generator 201 and the X-ray detector 202, it can be assumed that the crack occurred during compression by the press device 180. Note that the control device 130 can determine the type of defect appearing in the X-ray image, for example, by pattern matching, and determine whether the defect is a crack or another defect such as a cavity. As with the defect detection process, the defect determination process by the control device 130 may be performed using AI.

[0086] As described above, the battery electrode manufacturing apparatus 1000 according to the first embodiment includes a conveying device 120 that conveys a strip-shaped current collector 21B, a current collector 21B that supplies an electrode composition 22c to the conveyed current collector 21B, and a control device 130 that inspects the electrode composition 22c on the current collector 21B using X-rays and performs processing according to the inspection results. With this configuration, the battery electrode manufacturing apparatus 1000 according to the first embodiment can improve the quality of the active material layer in a battery. That is, the control device 130 can detect not only surface defects such as dents, but also internal defects such as cavities and cracks, and perform appropriate processing depending on the situation.

[0087] For example, if a defect is detected before compression by the press device 180, additional electrode composition 22c' can be supplied from the replenishing device 170, thereby preventing low-density portions from occurring in the electrode active material layer 22. Furthermore, if a defect is detected after compression by the press device 180, or if it is difficult to address the problem by replenishing or the like, the product can be removed from the production line as a defective product. Furthermore, by feeding back the defect detection results to the compression conditions in the press device 180, the compression conditions can be optimized.

[0088] The above-described embodiment is merely an example, and various modifications are possible.

[0089] For example, although X-rays have been described as an example of radiation, inspections may be performed using other types of radiation. For example, instead of the X-ray generator 161, the X-ray detector 162, the X-ray generator 201, and the X-ray detector 202, a gamma ray inspection device or a beta ray inspection device may be provided.

[0090] Furthermore, some of the components shown in FIG. 2 may be omitted as appropriate. For example, either or both of the thickness measurement device 150 and the thickness measurement device 190 may be omitted. Surface defects, such as dents, on the electrode composition 22c can also be detected from the results of a radiological inspection. In the inspection using the X-ray generator 161 and the X-ray detector 162 described above, the X-rays are irradiated in only one direction, making it difficult to determine the Y-direction position of the defect and potentially making it impossible to distinguish between dents and cavities. However, as shown in FIG. 6A, a similar process may be performed regardless of the type of defect. Alternatively, X-rays may be irradiated from multiple directions to enable differentiation between dents and cavities. Furthermore, while FIG. 2 illustrates an example in which radiological inspection is performed twice, once before and once after compression by the press device 180, radiological inspection may be performed only once, either before or once after compression by the press device 180.

[0091] In the above-described embodiment, an example has been described in which the electrode composition 22c itself is inspected for structural defects such as dents, cavities, and cracks, but the embodiment is not limited to this. For example, the control device 130 may detect the presence of foreign matter such as metal based on the results of an inspection using radiation. If foreign matter is found to be present, the control device 130 may take action according to the inspection results, such as removing the foreign matter from the electrode composition 22c or rejecting the product as a defective product from the production line.

[0092] Furthermore, in the above-described embodiment, an example of inspecting for defects and foreign matter has been described, but the embodiment is not limited thereto. For example, the control device 130 may measure the amount of electrode composition 22c supplied onto the current collector 21B based on the results of the inspection using radiation. That is, the control device 130 may measure the basis weight of the electrode composition 22c. Here, for example, if the measured basis weight is partially reduced, additional electrode composition 22c can be supplied from the replenishing device 170, as in the case where a depression is detected. Furthermore, if the basis weight is reduced or increased overall, the control device 130 may perform feedback control to adjust the supply amount of electrode composition 22c. For example, the control device 130 can adjust the overall basis weight to approach the target value by adjusting the rotation speed of the moving belt provided in the electrode composition supply device 140 or the conveying speed of the current collector 21B by the conveying device 120.

[0093] In the above-described embodiment, the electrode composition 22c is compressed by the press device 180, and the roller 145 is described as a leveling roller that applies pressure to the extent that the surface of the electrode composition 22c is flattened. However, the electrode composition 22c may be compressed by the roller 145. For example, the electrode composition 22c may be compressed in two stages by the roller 145 and the press device 180. Alternatively, the press device 180 may be omitted, and the electrode composition 22c may be compressed only by the roller 145. In these cases, the roller 145 is an example of a pressure applying unit.

[0094] In the above-described embodiment, the strip-shaped substrate film on which the electrode composition 22c is placed is described as the strip-shaped current collector 21B, but this is not limited thereto. For example, instead of the strip-shaped current collector 21B shown in FIG. 2, a strip-shaped separator sheet or a strip-shaped release film may be used as the substrate film. The strip-shaped separator sheet can be later trimmed to form the separator 30 shown in FIG. 1.

[0095] For example, when a separator sheet is used as the base film, the electrode composition 22c is supplied onto the separator sheet, a frame 35 is supplied to the separator sheet in a position surrounding the electrode composition 22c, a current collector 21B is supplied to the surface of the electrode composition 22c opposite the separator sheet, and the separator sheet and the current collector 21B are trimmed to a predetermined shape, thereby producing the positive electrode 20a or the negative electrode 20b.

[0096] When a release film is used as the substrate film, electrode composition 22c is supplied onto the release film, frame 35 is supplied on the release film in a position surrounding electrode composition 22c, current collector 21B is supplied to the surface of electrode composition 22c opposite the release film, the release film is recovered, and then a separator sheet is supplied to the surface opposite current collector 21B, and current collector 21B and separator sheet are trimmed to a predetermined shape, thereby producing positive electrode 20a or negative electrode 20b. Note that instead of supplying a separator sheet and then trimming it, separator 30 may be supplied to electrode composition 22c.

[0097] Alternatively, the positive electrode 20a or the negative electrode 20b can be produced by supplying the electrode composition 22c onto a release film, supplying a frame 35 on the release film in a position surrounding the electrode composition 22c, supplying a separator sheet to the surface of the electrode composition 22c opposite the release film, and after recovering the release film, supplying the current collector 21B to the surface opposite the separator sheet, and trimming the separator sheet and the current collector 21B to a predetermined shape. Note that instead of supplying the current collector 21B and then trimming it, the current collector 21 trimmed to a predetermined shape may be supplied to the electrode composition 22c.

[0098] In the above-described embodiment, the electrode composition 22c is supplied in predetermined lengths by repeatedly starting and stopping the supply of the electrode composition 22c to the base film, but the embodiment is not limited to this. That is, the electrode composition 22c may be supplied to the base film continuously.

[0099] For example, a sheet of electrode composition 22c alone can be produced by continuously supplying electrode composition 22c onto a release film as a base film and compressing it, and then peeling electrode composition 22c from the release film. The sheet of electrode composition 22c alone can then be trimmed to a predetermined size and combined with a frame 35, a current collector 21B, and a separator 30 to produce positive electrode 20a or negative electrode 20b. The order in which frame 35, current collector 21B, and separator 30 are supplied to trimmed electrode composition 22c is arbitrary.

[0100] Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configurations are not limited to these embodiments, and modifications, combinations, deletions, and the like of the configurations are within the scope of the present invention. Furthermore, it goes without saying that the configurations shown in each embodiment can be appropriately combined and used. When using the lithium-ion secondary battery exemplified above, the secondary battery includes batteries using a liquid material as the electrolyte and batteries using a solid material as the electrolyte (so-called all-solid-state batteries). Furthermore, the battery in this embodiment includes batteries using a metal foil (metal current collector foil) as the current collector, and batteries using a so-called resin current collector made of a resin to which a conductive material has been added instead of the metal foil. When the resin current collector is used as a resin current collector for a bipolar electrode, a bipolar electrode may be formed by forming a positive electrode on one side of the resin current collector and a negative electrode on the other side. The battery in this embodiment includes a battery in which an electrode is formed by applying a positive electrode or negative electrode active material, etc. to a positive electrode or negative electrode current collector using a binder, and in the case of a bipolar battery, includes a battery in which a bipolar electrode is formed by applying a positive electrode active material, etc. to one surface of a current collector using a binder to form a positive electrode layer, and applying a negative electrode active material, etc. to the opposite surface using a binder to form a negative electrode layer. [Explanation of symbols]

[0101] 10: Single cell 20: Electrode 20a: Positive electrode 20b: Negative electrode 21, 21B: Current collector 21a: Positive electrode current collector layer 21b: Negative electrode current collector layer 21R: Current collector roll 22: Electrode active material layer 22a: Positive electrode active material layer 22b: Negative electrode active material layer 22c: Electrode composition 30: Separator 35:Frame body 110: Chamber 120:Transportation device 130: Control device 140: Electrode composition supply device 141: Hopper 142:Screw conveyor 143: Wall material 144: Wall material 145: Laura 146: Shutter 150: Thickness measuring device 161: X-ray generator 162: X-ray detector 170: Replenishment device 171: Hopper 172:Screw conveyor 173: Geared motor 180: Press equipment 181: Upper roller 182: Lower roller 190: Thickness measuring device 201: X-ray generator 202: X-ray detector 1000:Battery electrode manufacturing equipment

Claims

1. a supply unit that supplies an electrode composition containing an active material to the transported substrate film; a pressure unit that compresses the electrode composition formed on the substrate film; an inspection unit that irradiates the substrate film and the electrode composition with X-rays and performs an inspection using the X-rays; a control unit that executes processing according to the results obtained by the inspection unit; A battery electrode manufacturing apparatus comprising:

2. 2. The battery electrode manufacturing apparatus according to claim 1, wherein the inspection unit comprises an X-ray irradiation unit arranged on one side of the substrate film and the electrode composition, and an X-ray detection unit arranged on the other side of the substrate film and the electrode composition.

3. 2 . The battery electrode manufacturing apparatus according to claim 1 , wherein the inspection unit performs the inspection by irradiating the substrate film and the electrode composition before compression by the pressure unit with X-rays.

4. 4. The battery electrode manufacturing apparatus according to claim 3, wherein the inspection unit further performs the inspection by irradiating the base film and the electrode composition compressed by the pressure unit with X-rays.

5. 2. The battery electrode manufacturing apparatus according to claim 1, wherein, when a defect is detected in the electrode composition on the base film as a result of the inspection, or when the control unit measures the basis weight of the electrode composition measured as a result of the inspection and there is a portion where the basis weight is low, the control unit supplies additional electrode composition to compensate for the defect or the portion where the basis weight is low as the processing.

6. 6. The battery electrode manufacturing apparatus according to claim 5, wherein the defect is a cavity formed inside the electrode composition on the substrate film.

7. 5 . The battery electrode manufacturing apparatus according to claim 4 , wherein the control unit controls compression conditions in the pressure unit according to a result of detection of defects in the electrode composition after compression as the processing.

8. 8. The battery electrode manufacturing apparatus according to claim 7, wherein the defect is a crack that occurs in the electrode composition after compression.

9. 8. The battery electrode manufacturing apparatus according to claim 7, wherein the control unit controls compression conditions in the pressure unit according to the detection results of defects in the electrode composition before compression and the detection results of defects in the electrode composition after compression.

10. 2. The battery electrode manufacturing apparatus according to claim 1, wherein the inspection unit generates an X-ray image based on the X-ray detection result and analyzes the X-ray image to detect defects in the electrode composition on the substrate film.

11. 2. The battery electrode manufacturing apparatus according to claim 1, wherein the control unit further measures a thickness of the electrode composition on the substrate film, and executes the processing based on the thickness measurement result and the inspection result.

12. An electrode composition containing an active material is supplied to the substrate film being conveyed, compressing the electrode composition formed on the substrate film; irradiating the substrate film and the electrode composition with X-rays and performing an inspection using the X-rays; Execute a process according to the results obtained from the inspection A method for manufacturing an electrode for a battery, comprising:

13. 13. The method for manufacturing a battery electrode according to claim 12, wherein the inspection is performed using an X-ray irradiation unit arranged on one side of the substrate film and the electrode composition, and an X-ray detection unit arranged on the other side of the substrate film and the electrode composition.

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