Manufacturing method for electrode film and manufacturing device for electrode film

Abstract

Provided are a manufacturing method for an electrode film and a manufacturing device for an electrode film, the manufacturing method including a step for supplying an electrode material to a support body to be conveyed and a step for bringing a plurality of molding members sequentially into contact with the electrode material conveyed together with the support body and thereby forming an electrode film including the electrode material on the support body, wherein: the plurality of molding members include at least a first molding member and a second molding member that comes into contact with the electrode material after the first molding member; contact angles, which are the angles formed by the support body and the surfaces of the molding members contacted by the electrode material, are such that the contact angle in the first molding member is less than the contact angle in the second molding member; and the shortest distances between the molding members and the support body are such that the shortest distance in the first molding member is greater than the shortest distance in the second molding member.

Description

Method for manufacturing electrode film and manufacturing apparatus for electrode film

[0001] The present disclosure relates to a method for manufacturing an electrode film and a manufacturing apparatus for an electrode film.

[0002] In a quasi-solid battery, an electrode film can be formed without going through a drying process by previously mixing an electrolyte into an active material and a conductive assistant. Also, since the electrode film of a quasi-solid battery can be formed without including a binder, it is attracting attention as a battery with excellent recyclability.

[0003] In a coating process of forming an electrode material film on a current collector foil as a support, a solid content including an active material and a conductive assistant contained in the electrode material adheres to the current collector foil due to the viscosity, surface tension, etc. of the electrolyte contained in the electrode material, thereby forming a film.

[0004] In order to form an electrode film using a slurry-like electrode material for a quasi-solid battery, it is disclosed to apply the slurry-like electrode material using a frame and a blade (Patent Document 1 or Patent Document 2).

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2017-533548 Patent Document 2: Japanese Patent Application Laid-Open No. 2021-530829

[0006] From the viewpoint of improving battery performance, it is required to coat an electrode material with a higher solid content concentration and a higher yield stress in a film form. However, in the conventional method, a support, equipment, etc. with a larger pressure and strength are required, and coating is difficult.

[0007] The present disclosure has been made in view of the above circumstances. The problem to be solved by one embodiment of the present disclosure is to provide a method for manufacturing an electrode film and a manufacturing apparatus for an electrode film that appropriately form a film of an electrode material having a high yield stress.

[0008] Specific means for solving the above problems include the following aspects.

[0009] <1> A method for manufacturing an electrode film, comprising the steps of supplying an electrode material to a support being transported, and forming an electrode film containing the electrode material on the support by sequentially bringing a plurality of molded members into contact with the electrode material being transported together with the support, wherein the plurality of molded members include at least a first molded member and a second molded member that contacts the electrode material after the first molded member, and the contact angle formed by the surface of the molded member that the electrode material contacts and the support is such that the contact angle of the first molded member is smaller than the contact angle of the second molded member, and the shortest distance between the molded member and the support is such that the shortest distance of the first molded member is greater than the shortest distance of the second molded member. <2> The method for manufacturing an electrode film according to <1>, wherein the first molded member that the electrode material contacts has a contact angle in the range of 1° to 10°. <3> The method for manufacturing an electrode film according to <1> or <2>, wherein the difference between the contact angle of the first molded member and the contact angle of the second molded member is in the range of 2° to 6°, and the difference between the shortest distance of the first molded member and the shortest distance of the second molded member is in the range of 20 μm to 200 μm. <4> The method for manufacturing an electrode film according to any one of <1> to <3>, wherein at least one of the plurality of molded members vibrates in the range of 10 kHz to 100 kHz. <5> The method for manufacturing an electrode film according to any one of <1> to <4>, wherein at least one of the plurality of molded members vibrates with an amplitude in the range of 1 μm to 60 μm. <6> The method for manufacturing an electrode film according to any one of <1> to <5>, wherein the electrode material has a yield stress of 50 kPa or more. <7> An electrode film manufacturing apparatus comprising a transport means for transporting a support and an electrode material, and a plurality of molding members that contact the electrode material transported together with the support, wherein the plurality of molding members include at least a first molding member and a second molding member, the first molding member and the second molding member are arranged in this order from upstream in the transport direction, the contact angle formed by the surface of the molding member that contacts the electrode material and the support is such that the contact angle of the first molding member is smaller than the contact angle of the second molding member, and the shortest distance between the molding member and the support is such that the shortest distance of the first molding member is greater than the shortest distance of the second molding member.

[0010] According to one embodiment of the present disclosure, it is possible to provide a method for manufacturing an electrode film and an apparatus for manufacturing an electrode film that can appropriately produce an electrode film of an electrode material with a high yield stress.

[0011] Figure 1 is an explanatory diagram illustrating the contact angle θ and the shortest distance T. Figure 2 is an explanatory diagram illustrating the contact angle θ and the shortest distance T when the molded member is used in two stages. Figure 3 is an explanatory diagram illustrating the contact angle θ and the shortest distance T when the molded member is used in four stages.

[0012] Embodiments of this disclosure will be described below with reference to the drawings. This disclosure is not limited to the embodiments described below and can be implemented with appropriate modifications within the scope of the purpose of this disclosure. Components indicated by the same reference numerals in each drawing are considered to be the same component. Specific components and reference numerals that are duplicated in each drawing may not be described. Some components may be given reference numerals in each drawing. The sizes of the components in each drawing are conceptual and are not limited to the relative sizes of the components.

[0013] In this disclosure, a numerical range expressed using "~" means a range that includes the numbers before and after "~" as the lower and upper limits. In numerical ranges described in stages in this disclosure, the upper or lower limit stated in one numerical range may be replaced with the upper or lower limit of another numerical range described in stages. Also, in numerical ranges described in this disclosure, the upper or lower limit stated in one numerical range may be replaced with the values ​​shown in the examples.

[0014] In this specification, "orthogonal" does not mean exactly 90°, but rather 90° ± 10°, preferably 90° ± 5°.

[0015] In this disclosure, the term "process" includes not only independent processes but also processes that are not clearly distinguishable from other processes, as long as their intended purpose is achieved. In this disclosure, the amount of each component in a composition means the total amount of multiple substances present in the composition, unless otherwise specified, if multiple substances corresponding to each component are present in the composition. In this disclosure, two or more preferred embodiments or combinations of forms are referred to as more preferred embodiments or forms.

[0016] "Semi-solid battery" means a secondary battery having an electrode layer in which an electrolyte is mixed with an electrode active material and a conductive additive. In this disclosure, "transport direction" means the direction in which the electrode film, etc., is transported, and "width direction" means the direction perpendicular to the transport direction (the width direction of the electrode film, etc.). In this disclosure, "electrode material" means the material that becomes an electrode film after film formation, and is the object to be formed.

[0017] The background to the embodiments of this disclosure will be explained. Electrode materials for electrode films in quasi-solid-state batteries have the characteristics of being able to form an electrode film without using a drying process by mixing an electrolyte with the electrode active material and conductive additive in advance, and containing little binder. From the viewpoint of improving battery performance, there is a need to coat electrode materials with a higher solid content and a higher yield stress in a film form. Specifically, in some cases, an electrode material with a high solid content and, for example, a yield stress of 50 kPa or more is used to form a film. In this case, with conventional coating methods, a large pressure is applied to the electrode material during coating, causing the contained electrolyte to seep out onto the surface of the electrode material, making it impossible to maintain the desired amount of liquid, which can affect the performance of the manufactured battery.

[0018] The inventors diligently studied methods for appropriately coating electrode materials with high yield stress into a film, and focused on the application of a molded member to the electrode material. They then discovered a method to reduce the force required to deform the electrode film applied to the support by increasing the angle between the surface of the molded member in contact with the electrode material and the support, and decreasing the distance between the surface of the molded member and the support, as the application of the molded member progresses through multiple stages, thereby completing the embodiments of this disclosure.

[0019] The mechanism by which the above effects are obtained is not clear, but it is presumed to be as follows: When using an electrode material with a high yield stress to form an electrode film, the first molding member used during film formation (for example, the first molding member) has a small contact angle, which is the angle between the contact surface of the molding member that contacts the electrode material and the support, and the distance between the molding member and the support is increased. This allows the electrode material to be coated onto the support with good adhesion, even if the film thickness is high. Then, the contact angle of the molding member is gradually increased and the distance between the molding member and the support is gradually decreased toward the downstream side in the transport direction, thereby thinning the electrode material to the desired thickness. This makes it possible to form an electrode film with excellent adhesion to the support, a thin thickness, and the desired electrolyte volume without applying high pressure. By using multiple molding members in a multi-stage configuration, the balance between pressing force and frictional force between the support and the electrode material can be appropriately adjusted at each stage, making it possible to form a thin film of electrode material with a high yield stress.

[0020] <Method for Manufacturing an Electrode> An embodiment of the method for manufacturing an electrode includes a step of supplying electrode material to a support that is being transported (hereinafter also referred to as the electrode material supply step) and a step of forming an electrode film containing electrode material on a support by bringing a plurality of molded members into contact with the electrode material being transported together with the support (hereinafter also referred to as the electrode film formation step). The plurality of molded members include at least a first molded member and a second molded member that contacts the electrode material after the first molded member. The contact angle formed by the surface of the molded member that contacts the electrode material and the support is such that the contact angle of the first molded member is smaller than the contact angle of the second molded member, and the shortest distance between the molded member and the support is such that the shortest distance of the first molded member is greater than the shortest distance of the second molded member.

[0021] The process includes an electrode material supply step and an electrode film formation step. The contact angle formed between the surface of the molded member that the electrode material contacts and the support is smaller in the first molded member than in the second molded member, and the shortest distance between the molded member and the support is greater in the first molded member than in the second molded member. This allows for the appropriate formation of an electrode material with a high yield stress. "Appropriately forming a film" means that a continuous film with good adhesion to the support is formed without applying high pressure (for example, a vertical load of 1 ton or more), and includes the formation of an electrode film of good quality, such as high uniformity of film thickness.

[0022] (Electrode Material Supply Process) The electrode material supply process is a process of supplying electrode material to a support being transported. As the support, conventional supports used for quasi-solid-state batteries, such as current collector foil and temporary support, can be used. The electrode material can be prepared by mixing an electrode active material, a conductive additive, and an electrolyte. From the viewpoint of improving battery performance, the effects of the electrode film manufacturing method, which is one embodiment of this disclosure, are more pronounced when using an electrode material with a higher solid content concentration and a higher yield stress.

[0023] The electrode material is preferably an electrode material for the positive electrode layer containing an electrode active material such as a metal oxide. Positive electrode materials with a high solid content have a high yield stress and are difficult to deform, so the effects of the electrode film manufacturing method according to one embodiment of this disclosure are more pronounced. The electrode material is preferably an electrode material for the positive electrode layer of a quasi-solid-state battery. Electrode materials for the positive electrode layer of a quasi-solid-state battery have a low binder content but a high solid content, making them particularly difficult to coat into a thin film. According to the electrode film manufacturing method according to one embodiment of this disclosure, even when using an electrode material for the positive electrode layer of a quasi-solid-state battery, it is possible to coat it with a desired film thickness.

[0024] The electrode material preferably has a high solid content concentration including the electrode active material and conductive additive, and a yield stress of, for example, 50 kPa or more, more preferably 100 kPa or more, and even more preferably 120 kPa or more. According to one embodiment of the electrode manufacturing method of this disclosure, electrode materials having these yield stresses can be coated.

[0025] The yield stress of an electrode material is the yield stress (unit: kPa) measured using a rotational viscometer. Specifically, it is measured as follows: The mixed electrode material is placed in a container (e.g., a cylindrical cup), and pressure of approximately 0.1 MPa to 1 MPa is applied from above using a jig or similar device to compact it so that there are no gaps between the electrode materials, thereby preparing the sample for measurement. A precision rotational viscometer with a vane-type spindle (e.g., Brookfield Soft Solid Tester, RST-SST) is used, and the probe is inserted into the sample for measurement (i.e., the compacted electrode material). The stress change is read while rotating at a constant speed, and the yield stress is measured. The temperature during measurement is room temperature (i.e., 25°C).

[0026] Conventional methods can be used to supply electrode material to the support being transported. For example, a method can be used to supply string-shaped electrode material onto the positioned current collector foil.

[0027] (Electrode Film Formation Process) The electrode film formation process is a process of forming an electrode film containing electrode material on a support by sequentially bringing multiple molding members into contact with the electrode material, which is transported together with the support. By using multiple molding members and applying the molding members in multiple stages, electrode material with a high solid content and high yield stress can be gradually stretched and thinned to form a film. In this disclosure, applying one molding member to the electrode material is referred to as one stage. Therefore, sequentially applying two molding members is referred to as two stages.

[0028] The molding member is applied to the electrode material in a manner that levels the conveyed electrode material from above. The shape of the molding member is not limited as long as it can contact the electrode material and level it from above. To level electrode material with a high yield stress from above, a plate-shaped molding member may be used, which has a rectangular cross-section along the direction perpendicular to the conveying direction and extends in the direction perpendicular to the conveying direction (see Figure 1). The material of the molding member may be any material that can properly level the conveyed electrode material from above. It may also be surface-treated, such as with a coating, to enable proper leveling of the electrode material. The molding member includes a blade.

[0029] Multiple molding members are used. Depending on the type of electrode material, the desired electrode film thickness, etc., two or more molding members can be used in any number. Therefore, molding members can be applied to the electrode material in two or more stages at any stage.

[0030] Multiple molded members may be used in a continuous manner, where multiple molded members are placed one at a time along the transport path to continuously contact the electrode material being transported. Alternatively, multiple molded members may be used in a batch manner, where one of the multiple molded members is placed along the transport path to bring it into contact with the electrode material, then the transport is stopped, and in the next transport, another molded member is placed along the transport path to bring it into contact with the electrode material.

[0031] Furthermore, "transported electrode material" means the relative movement of the electrode material with respect to the molding member. In other words, "transported electrode material" includes both cases where the electrode material is transported and cases where the electrode material is not transported. Specifically, this includes cases where the electrode material is transported and the position of the molding member is fixed in the transport direction, and cases where the electrode material is not transported and its position is fixed in the transport direction, and the molding member moves in the opposite direction to the transport direction. In either case, it is included in the method for manufacturing an electrode film, which is one embodiment of this disclosure, and the effects of the method for manufacturing an electrode film, which is one embodiment of this disclosure, are achieved by the relative movement of the electrode material with respect to the molding member.

[0032] The multiple molded members include at least a first molded member and a second molded member positioned downstream in the transport direction and contacting the electrode material after the first molded member. That is, the first molded member and the second molded member are applied to the electrode material in the order of the first molded member and the second molded member. The contact angle, which is the angle formed between the surface of the molded member that contacts the electrode material and the support, is such that the contact angle of the first molded member is smaller than the contact angle of the second molded member, and the shortest distance between the molded member and the support is such that the shortest distance of the first molded member is greater than the shortest distance of the second molded member.

[0033] The contact angle is the angle formed between a surface of the molded member that comes into contact with the electrode material and the support. The molded member includes a tip that comes into contact with the electrode material when leveling the conveyed electrode material from above, and a contact surface that includes the tip and comes into contact with the electrode material.

[0034] As shown in Figure 1, the molding member 11 includes a tip portion 12 and a contact surface 13, and the tip portion 12 and contact surface 13 contact the electrode material 14. The electrode material 14 is placed on a support 15. The electrode material 14 and the support 15 are transported in direction y, and the position of the molding member 11 in direction y, which is the transport direction, and the direction b of the contact surface 13 are fixed. The molding member 11 and the electrode material 14 extend in direction x, which is the direction towards the back of the paper.

[0035] The angle formed between the contact surface 13 of the molded member 11, which the electrode material 14 contacts, and the support 15 is the contact angle θ between direction a and direction b, where b is the direction of the contact surface 13 and a is the direction of the support. The shortest distance between the molded member 11 and the support 15 is the distance T between the tip portion 12 and the support 15, and is the width of the gap between the tip portion 12 and the support 15.

[0036] Figure 2 shows the case where two molded members are arranged sequentially in the transport direction y (arrow direction). In the first molded member 11-1, the angle formed between the contact surface 13-1 of the first molded member 11-1, which the electrode material 14-1 contacts, and the support 15 is the contact angle θ1 between direction a and direction b-1, where b-1 is the direction of the contact surface 13-1 and a is the direction of the support. In the second molded member 11-2, the angle formed between the contact surface 13-2 of the second molded member 11-2, which the electrode material 14-2 contacts, and the support 15 is the contact angle θ2 between direction a and direction b-2, where b-2 is the direction of the contact surface 13-2 and a is the direction of the support. When the multiple molding members include a first molding member 11-1 and a second molding member 11-2 that contacts the electrode material 14-2 after the first molding member 11-1, the contact angle θ1 of the first molding member 11-1 is smaller than the contact angle θ2 of the second molding member 11-2.

[0037] The shortest distance between the first molded member 11-1 and the support 15 is the distance T1 between the tip portion 12-1 and the support 15, and is the width of the gap between the tip portion 12-1 and the support 15. Similarly, the shortest distance between the second molded member 11-2 and the support 15 is the distance T2 between the tip portion 12-2 and the support 15, and is the width of the gap between the tip portion 12-2 and the support 15. The distance T1 between the first molded member 11-1 and the support 15 is greater than the distance T2 between the second molded member 11-2 and the support 15.

[0038] As described above, the contact angle θ formed by the contact surface of the electrode material 14 on the molded member 11 and the support 15 is such that the contact angle θ1 in the first molded member 11-1 is smaller than the contact angle θ2 in the second molded member 11-2, and the shortest distance between the molded member and the support is such that the shortest distance T1 in the first molded member 11-1 is larger than the shortest distance T2 in the second molded member 11-2. As a result, an electrode material 14 with a high yield stress can be appropriately formed. The thickness of the electrode material 14-2 before the second molded member 11-2 comes into contact with the electrode material 14-2 is the same as the distance T1 in the first molded member 11-1, and the thickness of the electrode material 14-2 after coming into contact with the second molded member 11-2 is the same as the distance T2. Therefore, since T1 > T2, the film thickness of the electrode material 12 can be gradually reduced.

[0039] By using a first molding member 11-1 and a second molding member 11-2 with different contact angles θ, the direction of the force applied during coating can be changed from pressing against the support 15 to spreading it by gradually increasing the contact angle θ. Furthermore, by gradually decreasing the shortest distance T between the first molding member 11-1 and the second molding member 11-2, the electrode material 14 can be prevented from peeling off the support 15, and the force required for coating can be reduced.

[0040] By using multiple molding members 11, it becomes possible to apply and then spread the electrode material 14, which is a material with a high yield stress. That is, the lower the contact angle θ, the greater the force with which the molding member 11 presses the electrode material 14. The stronger the force with which the electrode material 14 is pressed against the support 15, the higher the stress within the electrode material 14, causing the electrolyte to seep out and increasing the frictional force with the support 15. This makes it easier for an interface to form between the support 15 and the electrode material 14, increasing the frictional force and adhesion force with the support 15, but also increasing the burden on the device. Therefore, the electrode material 14 is applied first to ensure adhesion between the electrode material 14 and the substrate. Then, from the next step onward, the frictional force with the support 15 is reduced, and the burden on the device is also reduced, while appropriately thinning the film thickness of the electrode material 12 attached to the support 15 in stages.

[0041] As described above, according to the method for manufacturing an electrode according to an embodiment of the present disclosure, an electrode material with a high yield stress can be appropriately formed into a film.

[0042] The forming member 11 that the electrode material 14 first contacts preferably has a contact angle θ within the range of 1° to 10°. More preferably, the contact angle θ is within the range of 4° to 7°. When within the above range, the electrode material 14, which is a material with a high yield stress, can be more reliably applied to the support 15.

[0043] Further, from the perspective of appropriate coating of the electrode material 14 with a high yield stress, the difference between the contact angle θ1 in the first forming member 11-1 and the contact angle θ2 in the second forming member 11-2 is preferably within the range of 2° to 6°, and more preferably within the range of 3° to 5°.

[0044] Further, from the perspective of appropriate coating of the electrode material 14 with a high yield stress, the difference between the shortest distance T1 in the first forming member 11-1 and the shortest distance T2 in the second forming member 11-2 is preferably within the range of 20 μm to 200 μm, and more preferably within the range of 50 μm to 100 μm.

[0045] Further, from the perspective of appropriate coating of the electrode material 14 with a high yield stress, the difference between the contact angle θ1 in the first forming member 11-1 and the contact angle θ2 in the second forming member 11-2 is within the range of 2° to 6°, and the difference between the shortest distance T1 in the first forming member 11-1 and the shortest distance T2 in the second forming member 11-2 is preferably within the range of 20 μm to 200 μm.

[0046] From the perspective of appropriate coating of the electrode material 14 with a high yield stress, the contact angle θ of the forming member 11 at each stage is preferably 1° to 45°, and more preferably 4° to 20°. Further, from the perspective of appropriate coating of the electrode material 14 with a high yield stress, the shortest distance T between the forming member 11 at each stage and the support 15 is preferably 100 μm to 600 μm, and more preferably 200 μm to 300 μm.

[0047] Two or more forming members can be used in any number, that is, the multi-stage can be two or more stages. From the perspective of appropriate coating of the electrode material 14 with a large yield stress, the number of stages is preferably 3 to 6 stages, and more preferably 4 to 5 stages. As an example, when forming a film of the electrode material 14 with a yield stress of 50 kPa to 200 μm, it can be 3 to 4 stages.

[0048] For example, the electrode material 14 may be coated on the support 15 using the forming member 11 in four stages. As shown in FIG. 3, the first forming member 11-1, the second forming member 11-2, the third forming member 11-3, and the fourth forming member 11-4 can be sequentially arranged along the conveying direction y.

[0049] The angle formed by the contact surface 13-3 that the forming member 11-3 has and with which the electrode material 14-3 contacts and the support 15 is the contact angle θ3 formed by the direction a of the support and the direction b-3 of the contact surface 13-3. Also, the angle formed by the contact surface 13-4 that the forming member 11-4 has and with which the electrode material 14-4 contacts and the support 15 is the contact angle θ2 formed by the direction a of the support and the direction b-4 of the contact surface 13-4. The contact angle θ has the relationship of θ1 < θ2 < θ3 < θ4.

[0050] The shortest distance between the forming member 11-3 and the support 15 is the distance T3 between the tip 12-3 and the support 15, which is the width of the gap between the tip 12-3 and the support 15. Also, the shortest distance between the forming member 11-4 and the support 15 is the distance T4 between the tip 12-4 and the support 15, which is the width of the gap between the tip 12-4 and the support 15. The distance T has the relationship of T1 > T2 > T3 > T4.

[0051] When using the forming member 11 in four stages, from the perspective of appropriate coating of the electrode material 14, the electrode material 14 preferably has a yield stress of 40 kPa to 120 kPa.

[0052] When using the molding member 11 shown in Figure 3 in four stages, molding members 11-1 and 11-2 are applied in batch mode, and then molding members 11-3 and 11-4 are applied in a continuous mode. Multiple molding members 11 can be used in any combination of batch and continuous modes. Multiple molding members 11 may all be used in batch mode, or multiple molding members 11 may all be used in a continuous mode. In this case, a molding member having multiple molding members 11 as a single unit may be used.

[0053] Furthermore, from the viewpoint of uniformity of the coating film of the electrode material 14, at least one of the multiple molded members 11 may be vibrated. As means for vibrating the molded members 11, mechanical vibrations such as ultrasonic vibrations and low-frequency vibrations, electromagnetic vibrations, vibrations using piezoelectric elements, etc., can be used. From the viewpoint of uniformity of the coating film of the manufactured electrode film, it is preferable to vibrate one or more of the multiple molded members 11, more preferably two or more molded members 11, even more preferably more than half of the multiple molded members 11, and particularly preferable to vibrate all of the multiple molded members 11.

[0054] From the viewpoint of uniformity of the coating film on the electrode material 14, it is preferable that at least one of the multiple molded members 11 vibrates in the range of 10 kHz to 100 kHz, and more preferably in the range of 15 kHz to 30 kHz. From the viewpoint of uniformity of the coating film on the electrode material 14, it is preferable that at least one of the multiple molded members 11 vibrates with an amplitude in the range of 1 μm to 60 μm, and more preferably with an amplitude in the range of 10 μm to 40 μm. From the viewpoint of uniformity of the coating film on the electrode material 14, it is preferable that at least one of the multiple molded members 11 vibrates in the range of 10 kHz to 100 kHz and with an amplitude in the range of 1 μm to 60 μm.

[0055] From the viewpoint of being able to realize at least one of the above-mentioned frequencies and amplitudes, ultrasonic vibration is preferred as the vibration means. The multiple molding members 11 may each vibrate at the same frequency, or they may vibrate at different frequencies. Furthermore, the multiple molding members 11 may each vibrate at the same amplitude, or they may vibrate at different amplitudes. They may also vibrate while changing the frequency or amplitude.

[0056] <Electrode Film Manufacturing Apparatus> An electrode film manufacturing apparatus, which is one embodiment of the present disclosure, comprises a transport means and a plurality of molding members. The transport means transports a support and an electrode material. The plurality of molding members come into contact with the electrode material transported together with the support. The plurality of molding members include at least a first molding member and a second molding member. The first molding member and the second molding member are arranged in this order from upstream in the transport direction, and the contact angle formed by the surface of the molding member that comes into contact with the electrode material and the support is such that the contact angle of the first molding member is smaller than the contact angle of the second molding member, and the shortest distance between the molding member and the support is such that the shortest distance of the first molding member is greater than the shortest distance of the second molding member.

[0057] According to an electrode film manufacturing apparatus, which is one embodiment of the present disclosure, electrode materials with high yield stress can be appropriately formed into electrode films.

[0058] An electrode film manufacturing apparatus, which is one embodiment of the present disclosure, is an apparatus for realizing the electrode film manufacturing method described above. As the transport means, a transport means conventionally known in the manufacture of electrode films can be used. The molded members and the like are the same as those described in the electrode film manufacturing method.

[0059] The present disclosure will be described in more detail below based on the examples. The materials, amounts used, proportions, processing content, and processing procedures shown in the following examples can be modified as appropriate, as long as they do not deviate from the spirit of the present disclosure. Therefore, the scope of the present disclosure should not be interpreted as being limited by the examples shown below.

[0060] (Examples 1, 2 and 1) As shown in Figure 2, electrode films were manufactured from electrode material 14 using a two-step method with a molded member 11. The electrode material 14 was manufactured using the following positive electrode material and negative electrode material to produce electrode films for the positive electrode and negative electrode, respectively. Three types of positive electrode material were used, with yield stresses of approximately 20 kPa, approximately 50 kPa, and approximately 80 kPa. Three types of negative electrode material were used, with yield stresses of approximately 10 kPa, approximately 30 kPa, and approximately 50 kPa. Note that "approximately" in the yield stress means within ±20%. Specifically, the contact angle and shortest distance at each of the two stages of molded member 11-1 and molded member 11-2 are shown in Table 1. Since neither molded member 11-1 nor molded member 11-2 was vibrated, "-" is written in the "Ultrasonic Vibration" column of Table 1. The transport speed, i.e., the coating speed, was 3 m / min.

[0061] (Examples 3 to 5) As shown in Figure 3, electrode films were manufactured from electrode material 14 using a four-step method with a molded member 11. Similar to Example 1, electrode films for the positive electrode and negative electrode were manufactured using the following electrode materials for the positive electrode and negative electrode, respectively. Three types of electrode materials were used for the positive electrode, with yield stresses of approximately 20 kPa, approximately 50 kPa, and approximately 80 kPa. Three types of electrode materials were used for the negative electrode, with yield stresses of approximately 10 kPa, approximately 30 kPa, and approximately 50 kPa. Note that "approximately" in the yield stress means within ±20%. Specifically, the contact angle and shortest distance at each of the four stages of molded member 11-1, molded member 11-2, molded member 11-3, and molded member 11-4 are shown in Table 1. Some of the molded members were vibrated with ultrasonic vibration. If vibration was applied, "Yes" was written in the "Ultrasonic Vibration" column of Table 1; if vibration was not applied, "-" was written in the "Ultrasonic Vibration" column of Table 1. The transport speed, i.e., the coating speed, was 3 m / min. In Examples 4 and 5, where ultrasonic vibration was applied, the vibration was performed under conditions of a frequency of 20 kHz and an amplitude of 40 μm.

[0062] The electrode material 14 was manufactured using the following procedure.

[0063] =Electrode material for positive electrode= A mixture of 45 g of ethylene carbonate, 10 g of propylene carbonate, and 45 g of diethyl carbonate was mixed, and 13.4 g of 0.9 mol / L LiPF6 solution (electrolyte) was added to it. Then, 2.3 g of vinylene carbonate (VC) was added to prepare electrolyte X1. 2 g of conductive additive (Ketjenbrak: "Carbon ECP600JD" manufactured by Lion Specialty Chemicals) and 174 g of positive electrode active material (iron phosphate: "LFP NCO M121" manufactured by Aleees) were mixed in a mixer (Awatori Rentaro ARE-310, manufactured by Thinky Co., Ltd.) at 1500 rpm (revolutions per minute) for 30 seconds to prepare compound Y1 (176 g). Electrolyte solution X1 (64 g) was added to the kneaded mixture Y1 (176 g), and stirred at 1500 rpm for 120 seconds using an Awatori Rentaro (manufactured by Shinki Co., Ltd.) to obtain an electrode material for a positive electrode with a yield stress of approximately 50 kPa.

[0064] By changing the mixing ratio of electrolyte X1, a positive electrode material with a yield stress of approximately 20 kPa was obtained. Furthermore, by changing the mixing ratio of electrolyte X1, a positive electrode material with a yield stress of approximately 80 kPa was obtained.

[0065] =Negative electrode material= 6.3 g of conductive additive ("C-NERGY SUPER C45" manufactured by Imerys Graphite & Carbon) and 152.5 g of negative electrode active material ("MESOPHASE GRAPHITE POWDER A (MGP-A)" manufactured by China Steel Chemical Corporation) were mixed in a mixer (Awatori Rentaro ARE-310, manufactured by Thinky Co., Ltd.) at 900 rpm (revolutions per minute) for 5 seconds to prepare a mixture Y2 (158.8 g). Electrolyte X1 (81.2 g) was added to mixture Y2 (158.8 g) and mixed in an Awatori Rentaro (manufactured by Thinky Co., Ltd.) at 900 rpm for 18 seconds to obtain a negative electrode material with a yield stress of approximately 10 kPa. By changing the mixing ratio of electrolyte X1, a negative electrode material with a yield stress of approximately 30 kPa was obtained. Furthermore, by changing the mixing ratio of electrolyte X1, a negative electrode material with a yield stress of approximately 50 kPa was obtained.

[0066] (Evaluation Method) The obtained electrode films were visually inspected and evaluated according to the following evaluation criteria. The evaluation results are shown in Table 1.

[0067] =Evaluation Criteria= 5: A continuous electrode film is obtained with the desired thickness. 4: A continuous electrode film is obtained, but the thickness is slightly too thick. 3: Partial defects are observed within the film. 2: The electrode film initially adhered to the support, but some parts of the electrode film peeled off from the support. 1: The electrode film does not adhere to the support.

[0068]

[0069] The method for manufacturing electrode films described herein demonstrates that electrode materials with high yield stress can be appropriately fabricated.

[0070] The disclosure of Japanese Patent Application No. 2024-171855, filed on 30 September 2024, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually noted to be incorporated by reference.

Claims

1. A method for manufacturing an electrode film, comprising the steps of: supplying an electrode material to a support being transported; and forming an electrode film containing the electrode material on the support by sequentially bringing a plurality of molded members into contact with the electrode material being transported together with the support, wherein the plurality of molded members include at least a first molded member and a second molded member that contacts the electrode material after the first molded member, and the contact angle formed by the surface of the molded member that contacts the electrode material and the support is such that the contact angle of the first molded member is smaller than the contact angle of the second molded member, and the shortest distance between the molded member and the support is such that the shortest distance of the first molded member is larger than the shortest distance of the second molded member.

2. The method for manufacturing an electrode film according to claim 1, wherein the molded member that the electrode material first contacts has a contact angle within the range of 1° to 10°.

3. The method for manufacturing an electrode film according to claim 1, wherein the difference between the contact angle in the first molded member and the contact angle in the second molded member is within the range of 2° to 6°, and the difference between the shortest distance in the first molded member and the shortest distance in the second molded member is within the range of 20 μm to 200 μm.

4. The method for manufacturing an electrode film according to claim 1, wherein at least one of the plurality of molded members vibrates in the range of 10 kHz to 100 kHz.

5. The method for manufacturing an electrode film according to claim 1, wherein at least one of the plurality of molded members vibrates with an amplitude in the range of 1 μm to 60 μm.

6. The method for manufacturing an electrode film according to claim 1, wherein the electrode material has a yield stress of 50 kPa or more.

7. An electrode film manufacturing apparatus comprising: a transport means for transporting a support and an electrode material; and a plurality of molding members that contact the electrode material transported together with the support, wherein the plurality of molding members include at least a first molding member and a second molding member, the first molding member and the second molding member are arranged in this order from upstream in the transport direction, the contact angle formed by the surface of the molding member that contacts the electrode material and the support is such that the contact angle of the first molding member is smaller than the contact angle of the second molding member, and the shortest distance between the molding member and the support is such that the shortest distance of the first molding member is greater than the shortest distance of the second molding member.

Images