Battery unit, battery frame, method for manufacturing a battery unit, and method for manufacturing a battery frame

Abstract

This avoids malfunctions in the current collector and improves yield. [Solution] A method for manufacturing a battery unit applicable to a battery having a laminated structure, comprising the steps of: placing a rectangular active material layer 5 on a current collector 3 formed in the shape of a film; forming a frame 7a on the current collector 3 that surrounds the outer circumference of the active material layer 5 using a material that is plastic and hardenable; and pressing the frame 7a while it is plastic, wherein the frame 7a is plastically deformed by the pressing.

Description

Technical Field

[0001] The present invention relates to a battery unit applied to a battery having a laminated structure, a battery frame, a method for manufacturing the battery unit, and a method for manufacturing the battery frame.

Background Art

[0002] In recent years, lithium-ion batteries, which are high-capacity secondary batteries, have been used in various applications. The electrodes of lithium-ion batteries are composed of an active material layer, a current collector layer, a separator, and a frame that encloses the active material layer. For example, Patent Document 1 discloses an invention that enables the production of a battery having a desired shape. This production method is a method for manufacturing a lithium-ion battery, in which a first exterior part having a predetermined shape is formed using a material laminating device, a first current collector is disposed on the first exterior part, and a first frame part for fixing the peripheral edge of the main part of the first current collector disposed on the first current collector to the first exterior part is formed using the material laminating device. Further, a separator having a shape included in the predetermined shape is positioned and disposed such that its peripheral edge overlaps the first frame part. Also, a second frame part for fixing the peripheral edge of the separator disposed on the first frame part to the first frame part is formed using the material laminating device. Further, a second current collector is positioned and disposed such that the peripheral edge of the main part overlaps the second frame part, and a second exterior part is formed on the second frame part and the second current collector using the material laminating device.

[0003] Also, Patent Document 2 discloses an invention related to a battery pack suitable for use in a high-pressure environment. This battery pack includes a stack unit composed of a stack of a positive current collector, a positive active material layer, a separator, a negative active material layer, and a negative current collector in this order, and two or more single batteries having an annular frame member disposed around the positive active material layer, the separator, and the negative active material layer between the positive current collector and the negative current collector. For each single battery constituting the battery pack, the difference in thickness between the part where the frame member exists and the part where the stack unit exists is 0.3 mm or less, and for each single battery constituting the battery pack, the gap between the frame member and the stack unit is 0.5 mm or less. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Patent No. 6888937 specification [Patent Document 2] Japanese Patent Publication No. 2021-118132 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, in batteries with a layered structure, if there is always a gap between the active material layer and the frame, the gap is susceptible to stress because there is nothing to support the current collector, which can cause the current collector to tear, stretch, break, or crack. Furthermore, when manufacturing the frame, conventional methods involved punching out a resin sheet of a predetermined thickness to match the shape of the active material layer, but this resulted in poor yield and wasted costs.

[0006] This invention has been made in view of these circumstances, and aims to provide a battery unit, a battery frame, a method for manufacturing a battery unit, and a method for manufacturing a battery frame that avoid problems occurring in the current collector and improve yield. [Means for solving the problem]

[0007] To achieve the above objectives, the present invention employs the following means. Specifically, the battery unit of the present invention is a battery unit applicable to a battery having a laminated structure, comprising a current collector formed in the form of a film, an active material layer placed on the current collector, and a frame surrounding the outer periphery of the active material layer on the current collector, wherein at least a part of the active material layer and the frame are in close contact.

[0008] In this way, since the active material layer and at least a part of the frame are in close contact, it is possible to prevent cracks or malfunctions from occurring in the current collector. [Effects of the Invention]

[0009] According to the present invention, since a configuration can be adopted in which at least a part of the active material layer and the frame (frame body) are in close contact, it is possible to prevent cracks or malfunctions from occurring in the current collector when the battery is constructed. Furthermore, it is possible to improve yield and reduce costs. [Brief explanation of the drawing]

[0010] [Figure 1] This figure shows the manufacturing state of the battery unit according to this embodiment. [Figure 2] Figure 1 shows a cross-sectional view of AA, illustrating the manufacturing procedure for the battery unit. [Figure 3] This figure shows a first application example of the manufacturing state of the battery unit according to this embodiment. [Figure 4] Figure 3 shows a cross-sectional view of the battery box (BB), illustrating the manufacturing procedure for the battery unit. [Figure 5] Figure 3 shows a cross-sectional view of the battery box (BB), illustrating the manufacturing procedure for the battery unit. [Figure 6] Figure 3 shows a cross-sectional view of the battery box (BB), illustrating the manufacturing procedure for the battery unit. [Figure 7] Figure 3 shows a cross-sectional view of the battery box (BB), illustrating the manufacturing procedure for the battery unit. [Figure 8] This figure shows a second application example of the manufacturing state of the battery unit according to this embodiment. [Figure 9] Figure 8 shows a cross-sectional view of the CC, illustrating the manufacturing procedure for the battery unit. [Figure 10] Figure 8 shows a cross-sectional view of the CC, illustrating the manufacturing procedure for the battery unit. [Figure 11] Figure 3 shows a cross-sectional view of the battery box (BB), illustrating the manufacturing procedure for the battery unit. [Figure 12]It is a photograph of the frame before and after pressing. [Figure 13] It is a photograph of the frame before and after pressing. [Figure 14] It is a photograph of the frame before and after pressing. [Figure 15] It is a photograph showing the state of the frame alone coated in a spiral shape. [Figure 16] It is a diagram showing a method for manufacturing a battery unit. [Figure 17] Among the methods for manufacturing a battery unit, it is a diagram showing the cutting process. [Embodiments for Carrying Out the Invention]

[0011] The inventors of the present invention have noted that in a battery having a laminated structure, when there is always a gap between the active material layer and the frame, there is nothing to support the current collector in the gap portion, so it is likely to be loaded, and the current collector may break, stretch, break, or cracks may occur in the current collector or it may break. Also, the inventors have noted that in the conventional method for manufacturing a frame, the yield is poor and unnecessary costs are incurred. By providing a frame (frame body) made of a material having plasticity and curability on the outer periphery of the active material layer, it has been found that problems occurring in the current collector can be avoided and the yield can be improved, leading to the present invention.

[0012] That is, the battery unit of the present invention is a battery unit applied to a battery having a laminated structure, and includes a current collector formed in a film shape, an active material layer placed on the current collector, and a frame surrounding the outer periphery of the active material layer on the current collector, and at least a part of the active material layer and the frame are in close contact.

[0013] Thereby, the inventors of the present invention have made it possible to prevent cracks and problems from occurring in the current collector by bringing at least a part of the active material layer and the frame into close contact. Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.

[0014] [Basic Form of Battery Unit] Figure 1 shows the manufacturing state of a battery unit according to this embodiment. In the battery unit according to this embodiment, an active material layer 5 is placed on a current collector 3 formed in the form of a film. A frame 7a is formed on the outer circumference of the active material layer 5 using a material that is both plastic and curable. The material for the frame is applied onto the current collector 3 from a nozzle 9a (only the tip is shown). The current collector 3 can be either a positive electrode current collector or a negative electrode current collector. The active material layer 5 contains an electrolyte solution containing an electrolyte and a non-aqueous solvent, and can be either a positive electrode active material layer or a negative electrode active material layer. The frame 7a can be made of a thermoplastic resin, a thermosetting resin, or an ultraviolet curing resin.

[0015] Figure 2 is a cross-sectional view of AA shown in Figure 1, illustrating the manufacturing procedure for the battery unit. In Figure 2(A), the frame 7a is applied with the active material layer 5 placed on top of the current collector 3. Next, as shown in Figure 2(B), the frame 7a is pressed with a press machine 11 while it is still plastic. As a result, as shown in Figures 2(B) and (C), the frame 7a undergoes plastic deformation and adheres tightly to the active material layer 5. Subsequently, as shown in Figure 2(D), the excess portion is cut off to complete the battery unit 1 in which the active material layer 5 and the frame 7a are tightly adhered.

[0016] [First application example] Figure 3 shows a first application example of the manufacturing state of a battery unit according to this embodiment. In Figure 3, the nozzle 9b is shown to have circled the outer circumference of the active material layer 5 on the current collector 3 at least once, in this case about twice. The present invention is not limited to this number of circles. By forming the frame 7b in a spiral shape in this way, voids 13 and gas flow paths 15a are formed.

[0017] Figure 4 is a cross-sectional view of BB shown in Figure 3, illustrating the manufacturing procedure for the battery unit. In Figure 4(A), with the active material layer 5 placed on the current collector 3, the frame 7d is wrapped around the outer circumference of the active material layer 5 and coated in a spiral pattern. Here, the cross-sectional shape of the frame 7d perpendicular to the longitudinal direction is dome-shaped (semi-circular). Next, as shown in Figure 4(B), the frame 7d, while still plastic, is pressed with a press machine 11. As a result, as shown in Figures 4(B) and (C), the frame 7d undergoes plastic deformation and adheres tightly to at least a portion of the active material layer 5. At this time, a gas channel 15a is formed. Subsequently, as shown in Figure 4(D), by cutting off the excess portion, at least a portion of the active material layer 5 and the frame 7d adhere tightly, completing the battery unit 14 with the gas channel 15a.

[0018] Figure 5 is a cross-sectional view of BB shown in Figure 3, illustrating the manufacturing procedure for the battery unit. In Figure 5(A), with the active material layer 5 placed on the current collector 3, the frame 7c is wrapped around the outer circumference of the active material layer 5 and applied in a spiral pattern. Here, the cross-sectional shape of the frame 7c perpendicular to the longitudinal direction is octagonal. Next, as shown in Figure 5(B), the frame 7c, while still plastic, is pressed with a press machine 11. As a result, as shown in Figures 5(B) and (C), the frame 7c undergoes plastic deformation and adheres tightly to at least a portion of the active material layer 5. At this time, a gas channel 15b is formed. Subsequently, as shown in Figure 5(D), by cutting off the excess portion, the active material layer 5 and at least a portion of the frame 7c adhere tightly, completing the battery unit 12 with the gas channel 15b.

[0019] Figure 6 is a cross-sectional view of BB shown in Figure 3, illustrating the manufacturing procedure for the battery unit. In Figure 6(A), with the active material layer 5 placed on the current collector 3, the frame 7b is wrapped around the outer circumference of the active material layer 5 and applied in a spiral pattern. Here, the cross-sectional shape of the frame 7b perpendicular to the longitudinal direction is circular. Next, as shown in Figure 6(B), the frame 7b, while still plastic, is pressed with a press machine 11. As a result, as shown in Figures 6(B) and (C), the frame 7b undergoes plastic deformation and adheres to at least a portion of the active material layer 5. At this time, a gas channel 15c is formed. Subsequently, as shown in Figure 6(D), by cutting off the excess portion, at least a portion of the active material layer 5 and the frame 7b adhere to each other, completing the battery unit 10 with the gas channel 15c.

[0020] Figure 7 is a cross-sectional view of BB shown in Figure 3, illustrating the manufacturing procedure for the battery unit. In Figure 7(A), with the active material layer 5 placed on the current collector 3, the frame 7e is wrapped around the outer circumference of the active material layer 5 and applied in a spiral pattern. Here, the cross-sectional shape of the frame 7e perpendicular to the longitudinal direction is rectangular. Grooves 8 are also provided on the sides of the frame 7e. Next, as shown in Figure 7(B), the frame 7e, while still plastic, is pressed with a press machine 11. As a result, as shown in Figures 7(B) and (C), the frame 7e undergoes plastic deformation and adheres tightly to at least a portion of the active material layer 5. At this time, the grooves 8 of the frame 7e are formed as gas flow paths 15d. Subsequently, as shown in Figure 7(D), by cutting off the excess portion, at least a portion of the active material layer 5 and the frame 7e adhere tightly, completing the battery unit 16 with gas flow paths 15d.

[0021] [Second application example] Figure 8 shows a second application example of the manufacturing state of the battery unit according to this embodiment. In Figure 8, the nozzles 9b and 9c are shown to have circled the outer circumference of the active material layer 5 on the current collector 3 at least once. Nozzles 9b and 9c are differently shaped nozzles. As in the example shown in Figure 3, the shape of the cross section perpendicular to the longitudinal direction of the frame 7b of nozzle 9b is circular. On the other hand, the shape of the cross section perpendicular to the longitudinal direction of the frame 7f of nozzle 9c is radial (including asterisk shape). The frames 7b and 7f are coated so as to be arranged alternately. By forming the frames 7b and 7f alternately and in a spiral pattern in this way, voids 13 and gas flow paths 15a are formed.

[0022] Figure 9 is a cross-sectional view of the CC shown in Figure 8, illustrating the manufacturing procedure for the battery unit. In Figure 9(A), with the active material layer 5 placed on the current collector 3, the frame bodies 7b and 7f are applied in a spiral pattern, alternately circling the outer circumference of the active material layer 5. Here, the cross-sectional shape of frame body 7b perpendicular to the longitudinal direction is circular. The cross-sectional shape of frame body 7f perpendicular to the longitudinal direction is radial (asterisk-shaped), making it more easily crushed when pressed. Next, as shown in Figure 9(B), the frame bodies 7b and 7f, while still plastic, are pressed with a press machine 11. As a result, as shown in Figures 9(B) and (C), the frame bodies 7b and 7f undergo plastic deformation, and they adhere closely to each other to form a frame body 7g, which adheres to at least a portion of the active material layer 5. At this time, a gas flow path 15e is also formed. Subsequently, as shown in Figure 9(D), by cutting off the excess portion, at least a part of the frame 7g, which consists of the active material layer 5 and the frame 7b and frame 7f, is brought into close contact, completing the battery unit 18 having a gas flow path 15e.

[0023] Figure 10 is a cross-sectional view of the CC shown in Figure 8, illustrating the manufacturing procedure for the battery unit. In Figure 10(A), with the active material layer 5 placed on the current collector 3, the frame bodies 7b and 7h are applied in a spiral pattern, alternately circling the outer circumference of the active material layer 5. Here, the cross-sectional shape of frame body 7b perpendicular to the longitudinal direction is circular. The cross-sectional shape of frame body 7h perpendicular to the longitudinal direction is hollow (donut-shaped). Furthermore, frame bodies 7b and 7h are positioned at a certain distance apart. Next, as shown in Figure 10(B), the frame bodies 7b and 7h, while still plastic, are pressed with a press machine 11. As a result, as shown in Figures 10(B) and (C), frame bodies 7b and 7h undergo plastic deformation, and they adhere closely to each other to form a frame body 7i, which then adheres to at least a portion of the active material layer 5. Furthermore, at this time, a gas channel 15f is formed. Subsequently, as shown in Figure 10(D), by cutting off the excess portion, at least a part of the frame 7i, which consists of the active material layer 5 and the frame 7b and frame 7h, is brought into close contact, and the battery unit 20 having the gas channel 15f is completed.

[0024] Figure 11 is a cross-sectional view of BB shown in Figure 3, illustrating the manufacturing procedure for the battery unit. In Figure 11(A), with the active material layer 5 placed on the current collector 3, the frame 7j is applied in a spiral pattern around the outer circumference of the active material layer 5. Here, the cross-sectional shape of the frame 7j perpendicular to the longitudinal direction is circular. Furthermore, the frame 7j are arranged at regular intervals. This reduces the number of rotations required for application, thereby shortening the processing time. Next, as shown in Figure 11(B), the frame 7j, while still plastic, is pressed with a press machine 11. As a result, as shown in Figures 11(B) and (C), the frame 7j undergoes plastic deformation, and the frame 7j adheres tightly to at least a portion of the active material layer 5. At this time, a gas flow path 15g is also formed. Subsequently, as shown in Figure 11(D), by cutting off the excess portion, at least a part of the active material layer 5 and the frame 7j become tightly attached, completing the battery unit 22 having a gas flow path 15g. Note that the frame 7j parts may also become tightly attached to each other after being pressed with the press machine 11.

[0025] [Third application example] The battery unit has been described above, but there is also a method of coating the frame without placing the active material layer 5 on the current collector 3. In this case, the frame is coated on the current collector without the active material layer, and then the active material layer is placed on top before pressing. In this specification, the frame may also be referred to as the frame body.

[0026] Figure 12 shows photographs of the frame before and after pressing. Here, the frame, which was coated in a spiral pattern, was pressed using a jig with a 300 μm gap against a total thickness of 400 μm, consisting of a 300 μm thick frame, a 50 μm thick current collector, and a 50 μm thick release film. In other words, it was pressed with a stroke of 100 μm. As a result, the thickness of the frame became 250 μm. This is thought to be due to a 50 μm springback. As shown in Figure 12, a slight gas flow path can be seen after pressing.

[0027] Figure 13 shows photographs of the frame before and after pressing. Here, the frame, which was coated in a spiral pattern, was pressed using a jig with a gap of 400 μm against a total thickness of 410 μm, consisting of a frame with a thickness of 310 μm, a current collector with a thickness of 50 μm, and a release film with a thickness of 50 μm. In other words, it was pressed with a stroke of 10 μm. As a result, the thickness of the frame became 300 μm. As shown in Figure 13, a gas flow path can be visually observed after pressing.

[0028] Figure 14 shows photographs of the frame before and after pressing. Here, the frame, which was coated in a spiral pattern, was pressed using a jig with a gap of 300 μm against a total thickness of 450 μm, consisting of a frame with a thickness of 350 μm, a current collector with a thickness of 50 μm, and a release film with a thickness of 50 μm. In other words, it was pressed with a stroke of 150 μm. As a result, the thickness of the frame became 300 μm. As shown in Figure 14, it can be seen that the frame is crushed after pressing and no gas flow path has been formed. Note that the gas flow path is not an essential component of the present invention, so no problem arises even in this example.

[0029] Figure 15 is a photograph showing the frame coated in a spiral pattern. Here, a material with plasticity and curability has been applied in five rotations. This frame, as an example, has a thickness of 5 to 700 μm (more preferably 50 to 500 μm) and a width of 1 to 50 mm (more preferably 5 to 20 mm).

[0030] [Fourth application example] The fourth application example is a configuration in which the active material layer 5 is coated along its edges on a single-sheet current collector film. Figure 16 shows a method for manufacturing a battery unit. First, the current collector film 30 is transported continuously. Next, the active material layer 5 is placed on the current collector film 30 at predetermined intervals. Next, a plastic and curable material is applied from the nozzle 9d. The present invention is not limited to this order; the plastic and curable material may be applied from the nozzle 9d first, and then the active material layer 5 may be placed. In this case, the material is applied as a frame 7k along a pair of opposing edges of the active material layer 5 parallel to the transport direction of the current collector film 30, to a thickness greater than the thickness of the active material layer. Next, the plastic and curable material is applied from the nozzle 9e as a frame 7m along the edges (width direction) other than the specific pair of edges, to a thickness greater than the thickness of the active material layer 5. Next, the frame 7k and frame 7m are pressed with the roller 32 while they are still plastic, so that their thicknesses match the thickness of the active material layer 5. At this time, the frame 7k and frame 7m are plastically deformed by the press and come into close contact with at least a portion of the active material layer 5. Alternatively, the frame 7k may be applied to a thickness smaller than the thickness of the active material layer.

[0031] Figure 17 shows the cutting process in the manufacturing method of the battery unit. After pressing as shown in Figure 16, the unnecessary portion in the longitudinal direction is cut off with a cutter 34 while pressing with a roller 33. The unnecessary portion in the width direction is then cut off with a cutter 35. Finally, the frame scraps 7n and the battery unit 24 are produced. Although an example using cutters 34 and 35 is shown here, the present invention is not limited to this, and a method such as cutting with a laser may also be used.

[0032] By applying the coating to the surface in this manner, it is possible to shorten the processing time compared to the circular coating method, which applies the coating in a spiral pattern. In addition, it has the effect of making it easier to achieve a uniform thickness in the width direction. The embodiments of the present invention have been described above, but the present invention is not limited to these, and for example, "surface coating" may be performed on "single sheets", and so-called "bead coating" may be applied to a "continuous conveying method".

[0033] Next, an overview of the batteries to which the battery unit and battery frame according to this embodiment are applied will be described. The batteries to which the battery unit and battery frame according to this embodiment are applied are, for example, lithium-ion batteries. Lithium-ion batteries are used in the form of battery packs that are modularized by combining multiple lithium-ion single cells (also referred to as single cells or battery cells), or in the form of battery packs that combine multiple such battery packs to adjust the voltage and capacity. The following examples show lithium-ion secondary batteries, but are not limited to lithium-ion secondary batteries and include other secondary batteries.

[0034] <Single cell (battery cell)> A single cell has two electrodes (battery electrodes), a positive electrode and a negative electrode, and a separator. A battery pack can be made by combining multiple single cells. The separator is placed between the positive electrode and the negative electrode. In a battery pack, multiple single cells are stacked with the positive electrode and negative electrode facing the same direction. The separator holds the electrolyte. Thus, the separator functions as an electrolyte layer. The separator is placed between the electrode active material layers of the positive electrode and the negative electrode, preventing them from coming into contact with each other. Thus, the separator functions as a partition between the positive electrode and the negative electrode.

[0035] Examples of electrolytes held in the separator include electrolyte solutions or gel polymer electrolytes. Using these electrolytes ensures high lithium ion conductivity. Examples of separator forms include porous sheet separators or nonwoven fabric separators made of polymers or fibers that absorb and retain the electrolyte.

[0036] The positive electrode and the negative electrode each comprise a current collector, an electrode active material layer, and a frame. In this specification, the current collector may be either a positive electrode current collector or a negative electrode current collector. The active material layer contains an electrolyte solution comprising an electrolyte and a non-aqueous solvent, and may be either a positive electrode active material layer or a negative electrode active material layer. The frame may be made of a thermoplastic resin, a thermosetting resin, or an ultraviolet curing resin.

[0037] The electrode active material layer and the current collector are arranged in this order from the separator side. The frame is frame-shaped (annular). The frame surrounds the electrode active material layer. The positive electrode frame and the negative electrode frame are welded together to form a single unit. Alternatively, the positive electrode frame and the negative electrode frame may be manufactured as a single unit from the beginning. That is, the positive electrode frame and the negative electrode frame may be manufactured separately and then integrated, or they may be manufactured as a single component. <Specific examples of positive electrode current collectors> As the positive electrode current collector constituting the positive electrode current collector layer, a known current collector used in lithium-ion single cells can be used. For example, a known metal current collector and a resin current collector composed of a conductive material and resin (such as the resin current collector described in Japanese Patent Publication No. 2012-150905 and International Publication No. 2015 / 005116, etc.) can be used. From the viewpoint of battery characteristics, etc., the positive electrode current collector constituting the positive electrode current collector layer is preferably a resin current collector.

[0038] 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 thin sheets or metal foils. Alternatively, a metal current collector may be used in which the above metal materials are formed on the surface of a substrate made of materials other than the above metal materials by methods such as sputtering, vapor deposition, plating, electrodeposition, or coating.

[0039] The resin current collector preferably contains a conductive filler and a matrix resin. Examples of the matrix resin include polyethylene (PE), polypropylene (PP), and polymethylpentene (PMP), but are not particularly limited. The conductive filler is not particularly limited as long as it is selected from conductive materials, but examples include metal fillers such as nickel, aluminum, stainless steel (SUS), silver, copper, titanium, platinum, gold, and mixtures thereof; non-conductive materials such as particulate ceramic materials and resin materials coated with a metallic conductive material by plating, etc.; and conductive carbon fillers such as graphite, carbon black, carbon nanotubes, and mixtures thereof. The conductive filler may also be conductive fibers, which have a fibrous shape.

[0040] The resin current collector may contain other components (dispersants, lubricants, crosslinking accelerators, crosslinking agents, colorants, UV absorbers, plasticizers, etc.) in addition to the matrix resin and conductive filler. Furthermore, multiple resin current collectors may be laminated together, or a resin current collector may be laminated with metal foil.

[0041] The thickness of the positive electrode current collector layer is not particularly limited, but is preferably 5 to 150 μm. When multiple resin current collectors are laminated and used as the positive electrode current collector layer, the overall thickness after lamination is preferably 5 to 150 μm. The positive electrode current collector layer can be obtained, for example, by melt-kneading a matrix resin, a conductive filler, and a filler dispersant used as needed to obtain a conductive resin composition, and then forming it into a film using a known method. <Specific examples of positive electrode active materials> The positive electrode active material layer is preferably a non-binding mixture containing the positive electrode active material. Here, "non-binding" means that the position of the positive electrode active material in the positive electrode active material layer is not fixed, and the positive electrode active material is not irreversibly fixed to each other. When the positive electrode active material layer is non-binding, the positive electrode active material is not irreversibly fixed to each other, so it can be separated without mechanically destroying the interface between the positive electrode active material, and even when stress is applied to the positive electrode active material layer, the movement of the positive electrode active material prevents the destruction of the positive electrode active material layer, which is preferable. A non-binding positive electrode active material layer can be obtained by methods such as making the positive electrode active material layer a positive electrode active material layer that contains the positive electrode active material and electrolyte but does not contain a binder. In this specification, "binder" means a chemical agent that cannot reversibly fix the positive electrode active material to each other or to the positive electrode active material and the current collector. Such binders are used dissolved or dispersed in a solvent, and solidify without exhibiting tackiness on the surface as the solvent evaporates or is removed. Therefore, they cannot reversibly fix the positive electrode active materials together or the positive electrode active materials together with the current collector.

[0042] Examples of positive electrode active materials include, but are not limited to, composite oxides of lithium and transition metals, composite oxides containing two transition metal elements, and composite oxides containing three or more metal elements.

[0043] The positive electrode active material may be a coated positive electrode active material in which at least a portion of its surface is coated with a coating material containing a polymer compound. When the area around the positive electrode active material is coated with a coating material, the volume change of the positive electrode is mitigated, and the expansion of the positive electrode can be suppressed.

[0044] As the polymer compound constituting the coating material, for example, those described as resins for coating active materials in Japanese Patent Publication No. 2017-054703 and International Publication No. 2015 / 005117 can be suitably used.

[0045] The coating material may contain a conductive agent. Preferably, a conductive agent similar to the conductive filler contained in the positive electrode current collector layer can be used.

[0046] The positive electrode active material layer may contain an adhesive resin. Suitable adhesive resins include, for example, a resin for coating non-aqueous secondary battery active materials described in Japanese Patent Publication No. 2017-054703, which is mixed with a small amount of organic solvent to adjust its glass transition temperature to below room temperature, and an adhesive described in Japanese Patent Publication No. 10-255805. Note that an adhesive resin refers to a resin that does not solidify even when the solvent component is evaporated and dried, and retains its adhesive properties (the property of adhering by applying slight pressure without using water, solvents, heat, etc.). On the other hand, a solution-drying type electrode binder used as a binder refers to a material that dries and solidifies by volatilizing the solvent component, firmly bonding and fixing the active materials together. Therefore, the binder (solution-drying type electrode binder) and the adhesive resin described above are different materials.

[0047] The positive electrode active material layer may contain an electrolyte solution comprising an electrolyte and a non-aqueous solvent. As the electrolyte, those used in known electrolyte solutions can be used. As the non-aqueous solvent, those used in known electrolyte solutions can be used. For example, a mixture of ethylene carbonate (EC) and dimethyl carbonate (DMC), or a mixture of ethylene carbonate (EC) and propylene carbonate (PC) can be used.

[0048] The positive electrode active material layer may contain a conductive additive. Suitable conductive additives include conductive materials similar to the conductive fillers contained in the positive electrode current collector layer.

[0049] The thickness of the positive electrode active material layer 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.

[0050] The positive electrode composition supplied to form the positive electrode active material layer is a wet powder comprising a positive electrode active material and a non-aqueous electrolyte. Furthermore, the wet powder is more preferably in a pendulous or funnicular state. Alternatively, the positive electrode composition may be a clay-like (semi-solid) material formed by kneading the electrolyte into the positive electrode active material.

[0051] The proportion of non-aqueous electrolyte in a wet powder is not particularly limited, but in order to achieve a pendulous or funnicular state, it is desirable that the proportion of non-aqueous electrolyte be 0.20 to 40% by weight of the total wet powder in the case of the positive electrode.

[0052] <Specific examples of negative electrode current collectors> The negative electrode current collector constituting the negative electrode current collector layer can be appropriately selected and used, similar to the configuration 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 is preferably a resin current collector. The thickness of the negative electrode current collector layer is not particularly limited, but is preferably 5 to 150 μm.

[0053] <Specific examples of negative electrode active materials> The negative electrode active material layer is preferably an unbound mixture containing the negative electrode active material. The reasons why it is preferable for the negative electrode active material layer to be an unbound mixture, and the methods for obtaining an unbound negative electrode active material layer, are the same as the reasons why it is preferable for the positive electrode active material layer to be an unbound mixture, and the methods for obtaining an unbound positive electrode active material layer.

[0054] As the negative electrode active material, for example, carbon-based materials, silicon-based materials, and mixtures thereof can be used, but are not particularly limited.

[0055] The negative electrode active material may be a coated negative electrode active material in which at least a portion of its surface is coated with a coating material containing a polymer compound. When the negative electrode active material is surrounded by a coating material, the volume change of the negative electrode is mitigated, and the expansion of the negative electrode can be suppressed.

[0056] As the coating material, a material similar to the coating material constituting the coated positive electrode active material can be suitably used.

[0057] The negative electrode active material layer contains an electrolyte solution comprising an electrolyte and a non-aqueous solvent. The composition of the electrolyte solution can preferably be the same as that of the electrolyte solution contained in the positive electrode active material layer.

[0058] The negative electrode active material layer may contain a conductive additive. Suitable conductive additives include those similar to those contained in the positive electrode active material layer.

[0059] The negative electrode active material layer may contain an adhesive resin. The same adhesive resin as that used in the positive electrode active material layer can be suitably used.

[0060] The thickness of the negative electrode active material layer 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.

[0061] The negative electrode composition supplied to form the negative electrode active material layer is a wet powder comprising a negative electrode active material and a non-aqueous electrolyte. Furthermore, the wet powder is more preferably in a pendulous or funnicular state. Alternatively, the negative electrode composition may be a clay-like (semi-solid) material formed by kneading the electrolyte into the negative electrode active material.

[0062] The proportion of non-aqueous electrolyte in a wet powder is not particularly limited, but in order to achieve a pendulous or funnicular state, it is desirable that the proportion of non-aqueous electrolyte be 0.20 to 40% by weight of the total wet powder in the case of the negative electrode.

[0063] <Specific examples of separators> Examples of electrolytes held in the separator include electrolyte solutions or gel polymer electrolytes. By using these electrolytes, the separator can achieve high lithium ion conductivity. Examples of separator forms include porous films made of polyethylene or polypropylene, but are not particularly limited.

[0064] <Specific examples of frames> The frame is made of a material that is malleable and curable, and has insulating properties, sealing properties (liquid-tightness), heat resistance at battery operating temperatures, and electrolyte resistance. For example, polymer materials are preferred, and thermoplastic resins, thermosetting resins, or UV-curing resins can be used, with thermoplastic resins being more preferred among them. More specifically, examples include polyolefin resins, polyurethane resins, and fluororesins, and polyolefin resins are preferred because they have high durability, are easy to handle and obtain, and are inexpensive.

[0065] (1) The battery unit described above is a battery unit applicable to a battery having a stacked structure, comprising a current collector formed in the shape of a film, an active material layer placed on the current collector, and a frame surrounding the outer circumference of the active material layer on the current collector, wherein at least a part of the active material layer and the frame are in close contact.

[0066] In this way, since the active material layer and at least a part of the frame are in close contact, it is possible to prevent cracks or malfunctions from occurring in the current collector.

[0067] (2) In addition, the battery unit described above may further include a gas flow path in the frame.

[0068] This configuration makes it possible to remove the gas generated within the cell.

[0069] (3) Furthermore, the battery frame of the present invention is a battery frame applicable to a battery having a laminated structure, comprising a frame body that surrounds the outer periphery of the active material layer on the same plane as the active material layer, and an adhesion portion on the surface of the frame body facing the active material layer that is in close contact with the active material layer.

[0070] This configuration ensures that the active material layer and the frame are in close contact, preventing cracks or malfunctions from occurring in the current collector when the battery is assembled.

[0071] (4) In addition, the battery frame may further include a gas flow path in the frame body.

[0072] This configuration makes it possible to release the gas generated within the cell when the battery is assembled.

[0073] (5) Furthermore, the present invention relates to a method for manufacturing a battery unit, which is applicable to a battery having a laminated structure, and includes the steps of: placing an active material layer on a current collector formed in the shape of a film; and forming a frame on the current collector that surrounds the outer periphery of the active material layer using a material that is plastic and curable.

[0074] In this way, by using a material that is both plastic and hardenable to form a frame surrounding the outer periphery of the active material layer on the current collector, it becomes possible to directly form the frame on the current collector, eliminating waste loss that occurs when punching out the inside during frame processing, and thus increasing yield.

[0075] (6) The method for manufacturing the battery unit may also include a step of pressing the frame while it is in a plastic state, and the frame may be plastically deformed by the pressing and come into close contact with at least a part of the active material layer.

[0076] In this way, there are areas where the active material layer and the frame are in close contact, which prevents cracks and malfunctions from occurring in the current collector.

[0077] (7) In addition, in the method for manufacturing the battery unit described above, the step of forming the frame may be to form the frame by discharging the material by placing at least one nozzle that dispenses the material along all or part of the outside of the active material layer.

[0078] In this way, since the plastic and hardening material is discharged along all or part of the outside of the active material layer, it is possible to prevent cracks or malfunctions from occurring in the current collector.

[0079] (8) In addition, the manufacturing method of the battery unit described above may involve selecting the nozzle outlet such that the cross-sectional shape of the surface perpendicular to the longitudinal direction of the frame is one of the following: circular, elliptical, dome-shaped, rectangular with grooves on the side, radial, hollow donut-shaped, or square.

[0080] Thus, by making the cross-sectional shape of the surface perpendicular to the longitudinal direction of the frame circular, elliptical, dome-shaped, rectangular with grooves on the sides, radial, hollow donut-shaped, or square, the frame and the active material layer can be more easily brought into close contact when the frame is pressed. Furthermore, if the cross-section is rectangular with grooves on the sides, radial, or hollow donut-shaped, a flow path is formed in the machine when the frame is pressed, making it possible to release the gas generated in the cell.

[0081] (9) In addition, the manufacturing method of the battery unit may also involve making the nozzle that dispenses the material circle around the outside of the active material layer multiple times, and forming the frame by making the circled material come into contact with each other or separate from each other.

[0082] With this configuration, when the frame is pressed, a gas channel is formed, making it possible to vent the gas generated inside the cell.

[0083] (10) In addition, in the method for manufacturing the battery unit described above, the step of forming the frame may include a first step of applying the material parallel to a specific pair of opposing sides of the active material layer, and a second step of applying the material along sides other than the specific pair of sides.

[0084] Thus, by going through the first and second steps when forming the frame, it is possible to shorten the processing time compared to the method of applying the material in a circular manner around the outer circumference of the active material layer. In addition, it becomes easier to make the thickness of the frame uniform in the width direction.

[0085] (11) In addition, in the method for manufacturing the battery unit described above, if the material overlaps at the four corners of the frame in the first and second steps, the material may be reapplied to the parts where the material does not overlap.

[0086] Thus, in the first and second steps, if the material overlaps at the four corners of the frame, only the overlapping portion will become thicker. However, since the material is reapplied to the parts where it does not overlap, it is possible to make the thickness of the frame uniform.

[0087] (12) In addition, in the method for manufacturing the battery unit described above, the material may be any one of a thermoplastic resin, a thermosetting resin, or an ultraviolet curing resin.

[0088] This configuration makes it possible to produce goods at a low cost and efficiently.

[0089] (13) The method for manufacturing the battery unit may further include the step of cutting off the unnecessary current collector and frame.

[0090] This configuration makes it possible to adjust the shape of the battery unit.

[0091] (14) The above-mentioned method for manufacturing a battery unit is a method for manufacturing a battery unit that is applied to a battery having a laminated structure, and includes the steps of: continuously transporting a strip-shaped current collector formed in the form of a film; placing a plurality of active material layers on the current collector at predetermined intervals; applying a material having plasticity and curability to the current collector along a pair of opposing sides of the active material layer parallel to the transport direction of the current collector; and forming a frame by applying the material along sides other than the specific pair of sides.

[0092] This configuration makes it possible to improve the productivity of battery units.

[0093] (15) The method for manufacturing the battery unit may also include a step of pressing the frame while it is in a plastic state, and the frame may be plastically deformed by the pressing and come into close contact with at least a part of the active material layer.

[0094] In this way, there are areas where the active material layer and the frame are in close contact, which prevents cracks and malfunctions from occurring in the current collector.

[0095] (16) In addition, in the method for manufacturing the battery unit described above, the material may be any one of a thermoplastic resin, a thermosetting resin, or an ultraviolet curing resin.

[0096] This configuration makes it possible to produce goods at a low cost and efficiently.

[0097] (17) The method for manufacturing the battery unit may further include the step of cutting off the unnecessary current collector and frame.

[0098] This configuration makes it possible to adjust the shape of the battery unit.

[0099] (18) Furthermore, the present invention relates to a method for manufacturing a battery frame, which is applicable to a battery having a laminated structure, and includes the step of forming a frame body that surrounds the outer periphery of the active material layer on a current collector using a material that is plastic and curable.

[0100] In this way, by using a material that is both plastic and hardenable to form a frame surrounding the outer periphery of the active material layer on the current collector, it becomes possible to directly form the frame on the current collector, eliminating waste loss that occurs when punching out the inside during frame processing, and thus increasing yield.

[0101] (19) The method for manufacturing the battery frame may also include a step of pressing the frame body while it is in a plastic state, and the frame body may be plastically deformed by the pressing and come into close contact with at least a part of the active material layer.

[0102] This configuration allows for a tight seal between the active material layer and at least a portion of the frame body, thus preventing cracks or malfunctions from occurring in the current collector when the battery is assembled.

[0103] (20) In addition, in the method for manufacturing the battery frame described above, the step of forming the frame body may be to form the frame body by discharging the material by placing at least one nozzle that discharges the material along all or part of the outside of the active material layer.

[0104] In this way, since the plastic and hardening material is discharged along all or part of the outside of the active material layer, it is possible to prevent cracks or malfunctions from occurring in the current collector.

[0105] (21) In addition, the method for manufacturing the battery frame may be used to select the nozzle outlet such that the cross-sectional shape of the surface perpendicular to the longitudinal direction of the frame body is circular, elliptical, dome-shaped, rectangular with grooves on the side, radial, hollow donut-shaped, or square.

[0106] Thus, by making the cross-sectional shape of the surface perpendicular to the longitudinal direction of the frame body one of the following: circular, elliptical, dome-shaped, rectangular with grooves on the sides, radial, hollow donut-shaped, or square, the frame body and the active material layer can be more easily brought into close contact when the frame body is pressed. Furthermore, if the cross-section is rectangular with grooves on the sides, radial, or hollow donut-shaped, a flow path is formed in the machine when the frame body is pressed, making it possible to vent the gas generated in the cell.

[0107] (22) In addition, the method for manufacturing the battery frame may be to form the frame body by making the nozzle that discharges the material circle around the outside of the active material layer multiple times, and by making the circled material come into contact with each other or separate from each other.

[0108] This configuration creates a gas flow path, making it possible to remove gas generated within the cell.

[0109] (23) In addition, in the method for manufacturing the battery frame described above, the step of forming the frame may include a first step of applying the material parallel to a specific pair of opposing sides of the active material layer, and a second step of applying the material along sides other than the specific pair of sides.

[0110] Thus, by going through the first and second steps when forming the frame, it is possible to shorten the processing time compared to the method of applying the material in a circular manner around the outer circumference of the active material layer. In addition, it becomes easier to make the thickness of the frame uniform in the width direction.

[0111] (24) In addition, in the method for manufacturing the battery frame described above, if the material overlaps at the four corners of the frame in the first and second steps, the material may be reapplied to the parts where the material does not overlap.

[0112] Thus, in the first and second steps, if the material overlaps at the four corners of the frame, only the overlapping portion will become thicker. However, since the material is reapplied to the parts where it does not overlap, it is possible to make the thickness of the frame uniform.

[0113] (25) In addition, in the method for manufacturing the battery frame described above, the material may be any one of thermoplastic resin, thermosetting resin, or ultraviolet curing resin.

[0114] This configuration makes it possible to produce goods at a low cost and efficiently. [Explanation of Symbols]

[0115] 1 Battery unit 3 Current collector 5 Active material layer 7a Frame 7b Frame 7c frame 7d frame 7e frame 7f frame 7g frame 7h frame 7i frame 7j frame 7k frame 7m frame 7n scrap wood 8 grooves 9a Nozzle 9b Nozzle 9c nozzle 9d nozzle 9e nozzle 10 Battery Units 11 Press machine 12 Battery Units 13 Cavity 14 Battery Unit 15a Gas flow path 15b Gas flow path 15c Gas flow path 15d Gas flow path 15e Gas flow path 15f Gas flow path 15g gas flow path 16 Battery Unit 18 Battery Unit 20 Battery Units 22 Battery Unit 24 Battery Unit 30 Current collector film 32 Laura 33 Laura 34 Cutter 35 Cutter

Claims

1. A battery unit applicable to a battery having a layered structure, A current collector formed in a film shape, The active material layer placed on the current collector, The current collector comprises a frame that surrounds the outer periphery of the active material layer, A battery unit in which the active material layer and at least a portion of the frame are in close contact.

2. The frame further comprises a gas channel. The battery unit according to claim 1.

3. A battery frame applicable to batteries having a layered structure, A frame body that surrounds the outer periphery of the active material layer, on the same plane as the active material layer, The frame body has an adhesion portion on the surface facing the active material layer, which adheres closely to the active material layer. A battery frame equipped with the following features.

4. The frame body further comprises a gas flow path. Battery frame according to claim 3.

5. A method for manufacturing a battery unit applicable to a battery having a layered structure, A process of placing an active material layer on a current collector formed in the form of a film, A step of forming a frame surrounding the outer periphery of the active material layer on the current collector using a material that is both plastic and hardenable, A method for manufacturing a battery unit, including [the specified part of the method].

6. The process includes pressing the frame while it is in a state of plasticity, The frame is plastically deformed by the press and comes into close contact with at least a portion of the active material layer. A method for manufacturing a battery unit according to claim 5.

7. The process of forming the frame is as follows: The frame is formed by discharging the material by positioning at least one nozzle that discharges the material along all or part of the outside of the active material layer. A method for manufacturing a battery unit according to claim 5.

8. The nozzle outlet is selected such that the cross-sectional shape of the surface perpendicular to the longitudinal direction of the frame is one of the following: circular, elliptical, dome-shaped, rectangular with grooves on the sides, radial, hollow donut-shaped, or square. A method for manufacturing a battery unit according to claim 7.

9. The nozzle that dispenses the material is made to circle the outside of the active material layer multiple times, The frame is formed by the material being arranged in a circle and coming into contact with or separating from each other. A method for manufacturing a battery unit according to claim 7.

10. The process of forming the frame is as follows: A first step of applying the material parallel to a specific pair of opposing sides of the active material layer, The process includes a second step of applying the material along sides other than the aforementioned specific pair of sides, A method for manufacturing a battery unit according to claim 5.

11. If the material overlaps at the four corners of the frame during the first and second steps, the material is reapplied to the portion where it does not overlap. A method for manufacturing a battery unit according to claim 10.

12. The aforementioned material is one of the following: a thermoplastic resin, a thermosetting resin, or an ultraviolet curing resin. A method for manufacturing a battery unit according to any one of claims 5 to 11.

13. The process further includes cutting off the unnecessary current collector and frame. A method for manufacturing a battery unit according to any one of claims 5 to 12.

14. A method for manufacturing a battery unit applicable to a battery having a layered structure, A process of continuously transporting a strip-shaped current collector formed in a film-like manner, The process involves placing multiple active material layers on the current collector at predetermined intervals, A step of applying a material having plasticity and curability to the current collector along a pair of opposing sides of the active material layer parallel to the transport direction of the current collector, A step of forming a frame by applying the material along sides other than the aforementioned specific pair of sides, A method for manufacturing a battery unit, including [the specified part of the method].

15. The process includes pressing the frame while it is in a state of plasticity, The frame is plastically deformed by the press and comes into close contact with at least a portion of the active material layer. A method for manufacturing a battery unit according to claim 14.

16. The aforementioned material is one of the following: a thermoplastic resin, a thermosetting resin, or an ultraviolet curing resin. A method for manufacturing a battery unit according to claim 14 or 15.

17. The process further includes cutting off the unnecessary current collector and frame. A method for manufacturing a battery unit according to claim 14 or 15.

18. A method for manufacturing a battery frame applicable to batteries having a layered structure, A process of forming a frame body that surrounds the outer periphery of the active material layer on a current collector using a material that is both plastic and hardenable, A method for manufacturing a battery frame, including the method described above.

19. The process includes pressing the frame body while it is in a state of plasticity, The frame body is plastically deformed by the press and comes into close contact with at least a portion of the active material layer. A method for manufacturing a battery frame according to claim 18.

20. The process of forming the frame body is as follows: The frame body is formed by discharging the material by positioning at least one nozzle that discharges the material along all or part of the outside of the active material layer. A method for manufacturing a battery frame according to claim 18.

21. The nozzle outlet is selected such that the cross-sectional shape of the surface perpendicular to the longitudinal direction of the frame body is one of the following: circular, elliptical, dome-shaped, rectangular with grooves on the sides, radial, hollow donut-shaped, or square. A method for manufacturing a battery frame according to claim 20.

22. The nozzle that dispenses the material is made to circle the outside of the active material layer multiple times, The frame body is formed by the material being arranged in a circle and coming into contact with or separating from each other. A method for manufacturing a battery frame according to claim 20.

23. The process of forming the frame is as follows: A first step of applying the material parallel to a specific pair of opposing sides of the active material layer, The process includes a second step of applying the material along sides other than the aforementioned specific pair of sides, A method for manufacturing a battery frame according to claim 18.

24. If the material overlaps at the four corners of the frame during the first and second steps, the material is reapplied to the portion where it does not overlap. A method for manufacturing a battery frame according to claim 23.

25. The aforementioned material is one of the following: a thermoplastic resin, a thermosetting resin, or an ultraviolet curing resin. A method for manufacturing a battery frame according to any one of claims 18 to 24.

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