Method for manufacturing an energy storage device, recording device, and apparatus for manufacturing an energy storage device

Abstract

To provide a power storage device manufacturing method and apparatus which are capable of predicting individual differences in electrode materials to be used in cells in advance and grasping them afterwards.SOLUTION: A first cord 18 is formed along a length direction in an unformed region 16a of a current collector 16 of a lithium ion secondary battery. A first inspection device and a second inspection device use the first cord 18 to record inspection information in a recording device while identifying the position of an active material layer 17. As a result, it is possible to subsequently obtain the inspection information on the active material layer 17 corresponding to the position of first cord 18 in the length direction of the current collector 16, which makes it possible to predict or subsequently grasp individual differences in electrode materials used in cells.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a power storage device, a recording device, and a power storage device manufacturing apparatus.

Background Art

[0002] Japanese Patent Application Laid-Open No. 2015-16708 discloses a method for manufacturing an electrode formed by cutting an electrode material having a coating portion of an active material composite and an exposed portion of a metal foil on at least one surface of a long metal foil. In such a manufacturing method, a strip body is formed by cutting the electrode material into strip shapes. By stacking a plurality of such strip bodies, an electrode is manufactured. In such a manufacturing method, the coating portion of the electrode material is inspected to check whether there is a defective portion in the coating portion. When there is a defective portion in the coating portion, a mark is attached to the exposed portion. When cutting the electrode material, by detecting the mark with a mark detection device, it is possible to determine whether there is a defective portion in the coating portion. A portion including the coating portion determined to have a defective portion in the electrode material is not cut as a strip body and is not used for manufacturing an electrode. Further, since the mark is attached outside the region cut as a strip body in the electrode material, the strip body does not include the mark. Thereby, an electrode can be manufactured using only strip bodies that do not include a defective portion in the coating portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the electrode manufacturing method described above, the thickness of the active material mixture is not perfectly uniform during the coating process. As a result, individual differences occur in the electrode material used in the final assembled cell. Such individual differences cannot be predicted in advance or identified afterward. [Means for solving the problem]

[0005] The method for manufacturing an energy storage device disclosed herein includes the steps of: attaching a first identifier to a predetermined unformed region along the length of a strip-shaped current collector at predetermined intervals to identify the location of the region; forming an active material layer on the portion of the strip-shaped current collector excluding the unformed region; and recording inspection information obtained by checking the state of the active material layer while identifying the position of the strip-shaped current collector in association with the first identifier.

[0006] According to this method for manufacturing an energy storage device, it becomes possible to retrospectively acquire inspection information of the active material layer corresponding to the position where the first identifier is attached in the longitudinal direction of the current collector. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a perspective view of the lithium-ion secondary battery 10. [Figure 2] Figure 2 is a schematic longitudinal cross-sectional view along the line II-II in Figure 1. [Figure 3] Figure 3 is a schematic diagram of the electrode body 20. [Figure 4] Figures 4(a) to 4(f) are schematic diagrams of the manufacturing process of the electrode sheet 15. [Figure 5] Figure 5 is a schematic diagram of the energy storage device manufacturing apparatus 1. [Figure 6] Figure 6 shows an example of a database DT being constructed by the recording device 210. [Figure 7] Figure 7 is a flow chart showing the manufacturing method of the lithium-ion secondary battery 10. [Figure 8]Figure 8 is a flowchart showing a method for manufacturing a lithium-ion secondary battery 10 in a different order than the flowchart shown in Figure 7. [Modes for carrying out the invention]

[0008] The disclosures herein are explained below. Unless otherwise specified, the disclosures herein are not intended to limit the inventions described in the claims of this application. The drawings are schematic and do not necessarily reflect the actual objects. In addition, components and parts that perform the same function are appropriately denoted by the same reference numerals, and redundant explanations are omitted. In this specification, notations such as "X~Y" indicating a numerical range mean "X or more and Y or less" unless otherwise specified.

[0009] The disclosure herein relates to a method for manufacturing an energy storage device. The method for manufacturing an energy storage device disclosed herein is used, for example, to manufacture a lithium-ion secondary battery. The electrodes of the lithium-ion secondary battery are, for example, an aluminum or aluminum alloy positive electrode current collector and a copper or copper alloy negative electrode current collector.

[0010] <Lithium-ion secondary battery 10> Figure 1 is a perspective view of the lithium-ion secondary battery 10. Figure 2 is a schematic longitudinal cross-sectional view along the line II-II in Figure 1. Figure 3 is a schematic diagram of the electrode body 20. In Figure 2, the interior of the lithium-ion secondary battery 10 is exposed along one wide side of the roughly rectangular battery case 41. In Figure 2, the electrode body 20 is further shown in a partially broken cross-sectional view. The lithium-ion secondary battery 10 shown in Figure 2 is a so-called sealed battery in which the battery case 41 housing the electrode body 20 is sealed. In this embodiment, the battery case 41 is made of a roughly rectangular, rectangular metal case. The symbol X in the drawings indicates the direction of the long side of the battery case 41. The symbol Y (see Figure 1) indicates the direction of the short side perpendicular to the direction of the long side. The symbol Z indicates the height direction perpendicular to the direction of the short side and the direction of the long side. The structure of the battery case 41 is not limited to this form. For example, the battery case 41 may be a cylindrical case, or it may be a so-called bag-shaped laminate case that covers the electrode body 20.

[0011] As shown in Figure 2, the lithium-ion secondary battery 10 comprises an electrode body 20 and a battery case 41. The battery case 41 has a case body 41a having an opening 41a1 and a sealing plate 41b that closes the opening 41a1 of the case body 41a. The electrode body 20 is housed in the case body 41a. Internal terminals 55, 65 and external terminals 51, 61 are attached to the sealing plate 41b via a gasket 70 and an insulator 80. In this embodiment, the internal terminal 55 is connected to the positive electrode current collector 21a of the electrode body 20. The external terminal 51 is connected to the internal terminal 55 and constitutes the positive electrode terminal 50 outside the battery case 41. The internal terminal 65 is connected to the negative electrode current collector 22a (see Figure 3) of the electrode body 20. The external terminal 61 is connected to the internal terminal 65 and constitutes the negative electrode terminal 60 outside the battery case 41.

[0012] <Electrode body 20> As shown in Figure 3, in the electrode body 20, a positive electrode element 21 and a negative electrode element 22 face each other via a separator. The positive electrode element 21 comprises a positive electrode current collector 21a and a positive electrode active material layer 21b formed on the positive electrode current collector 21a and containing positive electrode active material. The negative electrode element 22 comprises a negative electrode current collector 22a and a negative electrode active material layer 22b formed on the negative electrode current collector 22a and containing negative electrode active material. The positive electrode element 21 and the negative electrode element 22 may each be in the form of a sheet. In this case, the positive electrode element may be a sheet-like member in which the positive electrode active material layer 21b is formed on both sides of a positive electrode current collector 21a composed of metal foil of a predetermined width and thickness. The negative electrode element may be a sheet-like member in which the negative electrode active material layer 22b is formed on both sides of a negative electrode current collector 22a composed of metal foil of a predetermined width and thickness. The sheet-like positive electrode element 21 is referred to as the positive electrode sheet. The sheet-like negative electrode sheet is referred to as the negative electrode sheet.

[0013] For example, the electrode body 20 may be a so-called wound electrode body. The electrode body 20 is composed of a positive electrode sheet 21 as a positive electrode element, a negative electrode sheet 22 as a negative electrode element, and separator sheets 31 and 32 as separators. The positive electrode sheet 21, the first separator sheet 31, the negative electrode sheet 22, and the second separator sheet 32 ​​are each long, strip-shaped members that are wound together while overlapping and aligning in both the length and width directions. The electrode body 20 is housed in the battery case 41, covered with an insulating film (not shown in the figure).

[0014] The positive electrode sheet 21 and the negative electrode sheet 22 are formed, for example, by cutting an electrode sheet wound in a roll. As shown in Figure 4(b), the electrode sheet 15 comprises a current collector 16 and an active material layer 17. Figures 4(a) to 4(f) are schematic diagrams of the manufacturing process of the electrode sheet 15. Details of Figures 4(a) to 4(f) will be described later.

[0015] The current collector 16 is a long, strip-shaped metal member. A metal material having the required conductivity can be used as the current collector 16. For example, aluminum, aluminum alloys, etc., can be used as the positive electrode current collector. For example, copper, copper alloys, etc., can be used as the negative electrode current collector. An active material layer 17 is formed on at least one surface of the strip-shaped current collector 16. In this embodiment, the active material layer 17 is formed on one side of the current collector 16. The active material layer 17 is a layer containing electrode active material. For example, a lithium transition metal composite oxide can be used as the positive electrode active material. For example, carbon materials, silicon-based materials, and mixed oxides thereof can be used as the negative electrode active material. The electrode active material layer may contain additives other than electrode active material, such as binders and conductive materials.

[0016] The electrode sheet 15 is formed by coating the current collector 16 with an electrode mixture slurry that will become the active material layer 17, and then drying it. The electrode mixture slurry is a paste-like substance formed by mixing a positive electrode active material or a negative electrode active material, a conductive material, a binder, etc., in a solvent. The electrode mixture slurry is applied by a coating device 102 (see Figure 5), which will be described later. The current collector 16 has an unformed region 16a. The unformed region 16a is located at a predetermined position along the length of the current collector 16. In this embodiment, the unformed region 16a is located at both ends in the width direction of the current collector 16. The electrode mixture slurry is applied to the current collector 16, excluding the unformed region 16a. As a result, the active material layer 17 is formed on the part of the current collector 16 excluding the unformed region 16a.

[0017] <Positive electrode sheet 21> The positive electrode sheet 21 is formed by using a positive electrode current collector as the current collector 16 and forming a positive electrode active material layer as the active material layer 17 in the electrode sheet 15 described above. As shown in FIG. 3, the positive electrode sheet 21 has a positive electrode active material layer 21b containing a positive electrode active material formed on one side of a positive electrode current collector 21a having a predetermined width and thickness, excluding an unformed portion 21a1 set with a constant width at one end in the width direction. A plurality of positive electrode tabs 21t are intermittently provided at predetermined positions along the length direction of the positive electrode sheet 21 in the unformed portion 21a1. The plurality of positive electrode tabs 21t each project toward the width direction of the positive electrode sheet 21.

[0018] For example, in the lithium ion secondary battery 10, the positive electrode active material layer 21b releases lithium ions during charging and absorbs lithium ions during discharging. Examples of the positive electrode active material include lithium transition metal composite materials. Various positive electrode active materials other than lithium transition metal composite materials have been proposed, and are not limited to lithium transition metal composite materials unless otherwise specified. The positive electrode active material layer 21b may be formed by coating and drying an electrode binder slurry. Further, in the present embodiment, a positive electrode protective layer 21p is provided on the positive electrode current collector 21a (unformed portion 21a1) at the edge of the positive electrode active material layer 21b. The positive electrode protective layer 21p is a layer that protects the unformed portion 21a1 and may be a layer containing an inorganic filler (for example, alumina).

[0019] 〈Negative electrode sheet 22〉 The negative electrode sheet 22 is such that in the above-described electrode sheet 15, a negative electrode current collector is used as the current collector 16, and a negative electrode active material layer is formed as the active material layer 17. The negative electrode sheet 22 has a negative electrode active material layer 22b containing a negative electrode active material formed on one side of a negative electrode current collector 22a having a predetermined width and thickness, excluding an unformed portion 22a1 set with a certain width at one edge in the width direction. In the present embodiment, a plurality of negative electrode tabs 22t are intermittently provided at predetermined positions along the length direction of the negative electrode sheet 22 in the unformed portion 22a1. The plurality of negative electrode tabs 22t each project toward the width direction of the negative electrode sheet 22. In the present embodiment, the positions where the plurality of negative electrode tabs 22t are provided are determined so that the positions of the plurality of negative electrode tabs 22t align in the wound state.

[0020] For the negative electrode current collector 22a, a material having required resistance properties such as electrolyte resistance and oxidation resistance is used in consideration of the operating potential of the negative electrode. For example, in the lithium-ion secondary battery 10, copper or a copper alloy mainly made of copper is generally used for the negative electrode current collector 22a. In the sheet-like negative electrode element 22, a copper foil mainly made of copper or copper may be used for the negative electrode current collector 22a. As the negative electrode active material contained in the negative electrode active material layer 22b, a material that can occlude a charge carrier during charging and release the charge carrier during discharging is used. For example, in a lithium-ion secondary battery, it is a material such as natural graphite that can occlude lithium ions during charging and release the lithium ions occluded during charging during discharging. The negative electrode active material has generally been variously proposed in addition to natural graphite and is not particularly limited. The negative electrode active material layer 22b may be, for example, in a state of a composite material in which such a negative electrode active material, a conductive material, a binder, etc. are mixed in a solvent, coated, and dried.

[0021] For the separator sheets 31 and 32, for example, a porous resin sheet through which an electrolyte having required heat resistance can pass is used. Various proposals have been made for the separator sheets 31 and 32, and they are not particularly limited. The separator sheets 31 and 32 may have functional layers such as an adhesive layer or a heat resistance layer (Heat Resistance Layer: HRL) on the surface of a base material made of a porous resin sheet. The heat resistance layer is, for example, a layer containing inorganic fillers such as alumina, silica, boehmite, magnesia, titania, etc., and a binder such as PVdF. The heat resistance layer may also serve as an adhesive layer.

[0022] Here, as shown in FIG. 3, the width Ln of the negative electrode active material layer 22b is formed wider than the width Lp of the positive electrode active material layer 21b, for example. The width Ls of the separator sheets 31 and 32 is wider than the negative electrode active material layer 22b. That is, as shown in FIG. 3, Lp < Ln < Ls. The positive electrode sheet 21, the first separator sheet 31, the negative electrode sheet 22, and the second separator sheet 32 are aligned in the length direction and are stacked and wound in order. Here, the negative electrode active material layer 22b covers the positive electrode active material layer 21b with the separator sheets 31 and 32 interposed therebetween. The negative electrode active material layer 22b is covered with the separator sheets 31 and 32. The positive electrode tab 21t of the positive electrode current collector 21a and the negative electrode tab 22t of the negative electrode current collector 22a are provided so as to protrude from the separator sheets 31 and 32 in opposite directions in the width direction. The positive electrode protective layer 21p faces the edge of the negative electrode sheet 22 on the side opposite to the side where the negative electrode tab 22t is provided through the separator sheets 31 and 32.

[0023] As shown in Figure 2, the electrode body 20 is flattened along a plane including the winding axis WL (see Figure 3) so that it can be housed in the case body 41a of the battery case 41. Along the winding axis WL of the electrode body 20, a positive electrode tab 21t is positioned on one side and a negative electrode tab 22t is positioned on the opposite side. Here, the electrode body 20 is exemplified as a wound electrode body in which a positive electrode sheet 21, a first separator sheet 31, a negative electrode sheet 22, and a second separator sheet 32 ​​are stacked and wound together. The configuration of the electrode body 20 is not limited to such a wound electrode body. The electrode body 20 may also be a so-called laminated electrode body in which a positive electrode sheet and a negative electrode sheet of a predetermined shape are stacked with a separator sheet in between, although this is not shown in the figures.

[0024] <Battery case 41> The battery case 41 houses the electrode body 20. In this embodiment, the battery case 41 has a case body 41a and a sealing plate 41b. The case body 41a is a bottomed member having an opening 41a1 on one side facing the bottom surface, and in this embodiment, it has a roughly rectangular parallelepiped shape with one side open. The sealing plate 41b is a plate material that is fitted into the opening 41a1 of the case body 41a. In this embodiment, the case body 41a and the sealing plate 41b are made of aluminum or an aluminum alloy mainly composed of aluminum, respectively, from the viewpoint of weight reduction and ensuring the required rigidity. In the embodiment shown in Figure 1, a wound-type electrode body 20 is exemplified, but the structure of the electrode body 20 is not limited to this form. The structure of the electrode body 20 may be, for example, a laminated structure in which a positive electrode sheet and a negative electrode sheet are alternately stacked with a separator sheet in between. Also, multiple electrode bodies 20 may be housed inside the battery case 41.

[0025] The battery case 41 may contain an electrolyte (not shown). A non-aqueous electrolyte can be used, which is obtained by dissolving a supporting salt in a non-aqueous solvent. Examples of non-aqueous solvents include carbonate-based solvents such as ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate. An example of a supporting salt is a fluorine-containing lithium salt such as LiPF6.

[0026] <Case body 41a> As shown in Figure 2, the case body 41a has a roughly rectangular shape with one side open. The case body 41a has a bottom portion 42 that forms a roughly rectangular bottom, a pair of wide portions 43, 44 (see Figure 1), and a pair of narrow portions 45, 46. The pair of wide portions 43, 44 each rise from the long side of the bottom portion 42. The pair of narrow portions 45, 46 each rise from the short side of the bottom portion 42. An opening 41a1 is formed on one side of the case body 41a, surrounded by the pair of wide portions 43, 44 and the pair of narrow portions 45, 46.

[0027] <Sealing plate 41b> The sealing plate 41b seals the opening 41a1 of the case body 41a. In this embodiment, as shown in Figure 1, the sealing plate 41b is rectangular in plan view. In this embodiment, the sealing plate 41b is provided with an electrolyte injection hole 41b1 and a safety valve 41b3. The electrolyte injection hole 41b1 is closed by attaching the sealing member 41b2 after the sealing plate 41b is attached to the opening 41a1 of the case body 41a and electrolyte is injected into the case body 41a. Figure 2 shows the sealing plate 41b assembled to the opening 41a1 of the case body 41a and welded. In Figure 2, the sealing member 41b2 is not attached to the sealing plate 41b. The safety valve 41b3 is thin-walled and is the part that ruptures when the pressure inside the battery case 41 exceeds a predetermined level.

[0028] As shown in Figure 2, a positive terminal 50 and a negative terminal 60 are attached to the sealing plate 41b. The positive terminal 50 has an external terminal 51 and an internal terminal 55. The negative terminal 60 has an external terminal 61 and an internal terminal 65. The internal terminals 55 and 65 are each attached to the inside of the sealing plate 41b via an insulator 80. The external terminals 51 and 61 are each attached to the outside of the sealing plate 41b via a gasket 70. The internal terminals 55 and 65 extend into the inside of the case body 41a. The unformed portion 21a1 of the positive current collector 21a and the unformed portion 22a1 of the negative current collector 22a of the electrode body 20 are attached to the internal terminals 55 and 65, which are attached to both sides of the sealing plate 41b in the direction of its long side.

[0029] The internal terminals 55 and 65 are made of metal. For the positive electrode internal terminal 55, aluminum or an aluminum alloy may be used to improve the bonding strength with the positive electrode tab 21t. For the negative electrode internal terminal 65, copper or a copper alloy may be used to improve the bonding strength with the negative electrode tab 22t and to provide the required resistance to electrolytes, oxidation, etc.

[0030] The external terminals 51 and 61 are made of metal. The metal used for the external terminals 51 and 61 is appropriately selected depending on the type of external connecting component such as a busbar. For example, aluminum, aluminum alloy, copper, copper alloy, etc., can be used for the external terminals 51 and 61. The external terminals 51 and 61 may be constructed by joining multiple metals by dissimilar metal joining. Although not shown in the figures, mounting holes are formed in the sealing plate 41b. An insulator 80 is attached to the inside of the sealing plate 41b through the mounting holes, and a gasket 70 is attached to the outside of the sealing plate 41b. A shaft portion is provided on one of the internal terminals 55 and 65 and the external terminals 51 and 61, and is inserted through the mounting hole with the gasket 70 and insulator 80 in between. The internal terminals 55 and 65 and the external terminals 51 and 61 are joined by the shaft portion inserted through the mounting hole.

[0031] The gasket 70 and insulator 80 should preferably be made of materials with excellent chemical resistance and weather resistance. In this embodiment, tetrafluoroethylene perfluoroalkyl vinyl ether copolymer (PFA) is used for the gasket 70. However, the material used for the gasket 70 is not limited to PFA. For example, polypropylene (PP), polyethylene (PE), polyphenylene sulfide resin (PPS), etc., may be used for the gasket 70. Polyphenylene sulfide resin (PPS) is used for the insulator 80. However, the material used for the insulator 80 is not limited to PPS.

[0032] During manufacturing, the lithium-ion secondary battery 10 has a gasket 70 and an insulator 80 attached to the sealing plate 41b, and the positive electrode terminal 50 and negative electrode terminal 60 are attached to it. Next, the electrode body 20 is attached to the sealing plate 41b by joining the positive electrode tab 21t to the internal terminal 55 of the positive electrode terminal 50 and the negative electrode tab 22t to the internal terminal 65 of the negative electrode terminal 60. Then, while inserting the electrode body 20 into the case body 41a through the opening 41a1, the sealing plate 41b is fitted into the opening 41a1 (see Figure 1) of the case body 41a. At this time, the winding axis WL (see Figure 3) of the electrode body 20 is positioned along the long side direction X of the case body 41a. The positive electrode tab 21t of the electrode body 20 is oriented toward the narrow surface portion 45. The negative electrode tab 22t is oriented toward the narrow surface portion 46. Then, as shown in Figure 2, the peripheral edge of the sealing plate 41b is joined to the edge of the opening 41a1 of the case body 41a. Such joining may be done, for example, by continuous welding without gaps. Such welding can be achieved, for example, by laser welding.

[0033] The battery case 41 may house multiple electrode bodies 20. Various structures can be employed for the internal terminals 55, 65, external terminals 51, 61, gasket 70, and insulator 80. For example, the internal terminals 55, 65, external terminals 51, 61, gasket 70, and insulator 80 should have structures appropriate to the structure of the electrode bodies 20 housed within them. In addition, one of the positive terminal 50 and the negative terminal 60 may be provided with a mechanism (CID (Current Interrupt Device)) that generates gas internally during overcharging, thereby interrupting the current as the internal pressure increases.

[0034] The above describes the configuration of the lithium-ion secondary battery 10 that will be manufactured.

[0035] Incidentally, the positive electrode sheet 21 and the negative electrode sheet 22 are formed, for example, by coating a long, strip-shaped current collector 16 with an active material mixture. In the manufacture of the cell, the required length of electrode sheet 15 is cut from a long, strip-shaped electrode sheet 15 and incorporated into the electrode body 20. The inventors of the present invention considered that if the thickness of the active material layer 17 along the length direction of the electrode sheet 15 used in the cell could be determined retrospectively during or after the cell assembly, it would be possible to improve the quality of the electrode body 20 assembly and predict individual differences in batteries.

[0036] Therefore, the inventors considered including the following steps in the method for manufacturing an energy storage device. Step A: Step of attaching a first code 18 to a predetermined unformed region 16a along the length of a strip-shaped current collector 16 at predetermined intervals to identify the location. Step B: Step of forming an active material layer 17 in the portion of the strip-shaped current collector 16 excluding the unformed region 16a. Process C: An inspection process that records inspection information obtained by identifying the position of the strip-shaped current collector 16 in conjunction with the first code 18, and inspecting the state of the active material layer 17.

[0037] According to this method for manufacturing energy storage devices, it becomes possible to retrospectively acquire inspection information of the active material layer 17 corresponding to the position where the first code 18 is attached along the length of the current collector 16. Therefore, the thickness of the active material composite along the length of the electrode sheet 15 used in the cell can be retrospectively determined during or after the cell is assembled. This makes it possible, for example, to predict or retrospectively determine individual differences in the electrode material used in the cell.

[0038] Figures 4(a) to 4(f) are schematic diagrams of the manufacturing process of the electrode sheet 15, as described above. Figure 4(a) shows the process of applying a first code 18 to a predetermined unformed region 16a along the length of the strip-shaped current collector 16 at predetermined intervals to identify its position on the strip-shaped current collector 16. Here, the cutting line CL, shown by the dashed line, is a line indicating the position to be cut when forming tabs 21t and 22t (see Figure 3). In this specification, forming tabs 21t and 22t by cutting the cutting line CL will be referred to as tab cutting. Details of the first code 18 will be described later. Figure 4(b) shows the process of forming the active material layer 17 in the portion of the strip-shaped current collector 16 excluding the unformed region 16a. Also, in the state shown in Figure 4(b), inspection information is recorded, which identifies the position of the strip-shaped current collector 16 in conjunction with the first code 18, while inspecting the state of the active material layer 17. Figure 4(c) shows the process of cutting the electrode sheet 15 in half in the width direction from the state shown in Figure 4(b).

[0039] Here, the unformed region 16a comprises a tab-forming region 16aa and a code-engraving region 16ab. The tab-forming region 16aa is the region of the unformed region 16a that becomes the tabs 21t and 22t (see Figure 3) described later when the code-engraving region 16ab is cut off. A first code 18 is formed in the code-engraving region 16ab. The first code 18 is an example of a first identifier in the present invention. The first code 18 is, for example, a two-dimensional code such as a QR code (registered trademark). The first code 18 may also be, for example, a one-dimensional code (barcode). Here, a one-dimensional code has multiple straight lines extending in one direction. Therefore, when forming a one-dimensional code, it is necessary to stop the transport of the electrode sheet 15 as appropriate, which is inefficient. Therefore, although the first code 18 may be a one-dimensional code, it is preferable that it be a two-dimensional code. Alternatively, the first identifier may be a predetermined mark or the like.

[0040] The first code 18 is applied at predetermined intervals along the length of the electrode sheet 15. The first code 18 is formed, for example, by laser light. In this embodiment, the first code 18 is applied, for example, every 1m along the length of the electrode sheet 15. The first code 18 is applied to the code marking area 16ab. The first code 18 has information for identifying the location on the current collector 16 where the first code 18 is formed. The information for identifying the location on the current collector 16 where the first code 18 is formed will be referred to as identification information. The identification information is registered as a sequence of numbers, for example, starting from the first code 18 attached to the front end of the electrode sheet 15, starting from 0, 1, 2, 3...

[0041] Furthermore, the inventors considered including the following steps in the method for manufacturing an energy storage device. Step D: Tab-cutting process, which involves reading the first code 18 of the strip-shaped current collector 16, identifying the position of the strip-shaped current collector 16, and performing a tab cut in the unformed region 16a. Process E: A process of attaching the second code 19 to predetermined positions on the tabs 21t and 22t formed in the tab cutting process. Process F: A winding process in which the second code 19 is read and the strip-shaped current collector 16 that has undergone tab-cutting is wound up.

[0042] Figure 4(d) is a schematic diagram showing the tab-cutting process in which tab cuts are made in the unformed region 16a. Figure 4(e) is a schematic diagram showing the process of attaching the second code 19 to predetermined positions on the tabs 21t and 22t formed in the tab-cutting process. Figure 4(f) is a diagram showing the process of reading the second code 19 and winding up the strip-shaped current collector 16 that has undergone the tab-cutting process.

[0043] The second code 19 is applied at predetermined intervals along the length of the electrode sheet 15. The second code 19 is an example of a second identifier in the present invention. The second code 19 is applied to predetermined positions on the tabs 21t and 22t formed by tab cutting. That is, the second code 19 is applied to the tab-forming region 16aa. The second code 19, like the first code 18, each has identification information. Furthermore, the second code 19 is linked to the identification information of all the first codes 18 contained in the positive electrode sheet 21 and the negative electrode sheet 22. The second code is a two-dimensional code, such as a QR code (registered trademark). However, like the first code 18, it may also be a one-dimensional code.

[0044] Furthermore, the inventors considered including the following steps in the method for manufacturing an energy storage device. Process G: A process of housing the electrode body 20 in the battery case 41 while reading the second code 19 of the electrode body 20 obtained in the winding process. Step H: Step to obtain the unique number assigned to the battery case 41. Step I: A process of recording the unique number of the battery case 41 and the second code of the electrode body 20 housed in the battery case 41, by linking them together.

[0045] Here, the battery case 41 (see Figure 2) in this embodiment is assumed to have a unique number. The unique number is a number that allows each battery case 41 to be identified individually, and is a unique number determined, for example, by the date of manufacture or the order in which they were manufactured. Although not shown in the illustration, for example, the unique number is engraved on the outer surface of the battery case 41. The unique number is read, for example, by a camera. The unique number may be assigned to the battery case 41 in advance, or it may be assigned by the energy storage device manufacturing apparatus 1 described later. However, the method of identifying the battery case 41 is not limited to this. To identify the battery case 41, for example, a unique barcode or the like may be printed on it.

[0046] <Energy Storage Device Manufacturing Equipment 1> Figure 5 is a schematic diagram of the energy storage device manufacturing apparatus 1. The method for manufacturing the energy storage device described above can be realized with the energy storage device manufacturing apparatus 1 shown in Figure 5. The energy storage device manufacturing apparatus 1 shown in Figure 5 will be described below. Here, the energy storage device manufacturing apparatus 1 is assumed to manufacture a lithium-ion secondary battery 10 (see Figure 1). The energy storage device manufacturing apparatus 1 comprises a code application line 1a and an electrode manufacturing line 1b. The code application line 1a comprises an unwinding roll 100, a first laser marking device 101, a coating device 102, and a winding roll 103. The electrode manufacturing line 1b comprises an unwinding roll 104, a first inspection device 105, a compression device 106, a second inspection device 107, a halving device 108, a cutting device 109, a second laser marking device 110, and a winding roll 111. Furthermore, the energy storage device manufacturing apparatus 1 is equipped with a control device 200, and the control device 200 is connected to each of the devices 100 to 111.

[0047] The electrode sheet 15 is wound onto unwinding rolls 100 and 104. The electrode sheet 15 is transported along a predetermined transport path and wound onto winding rolls 103 and 111. The unwinding rolls 100 and 104 and the winding rolls 103 and 111 may be attached to an auto-splice device that switches between rolls that have completed unwinding and winding and new rolls, respectively. In this embodiment, the unwinding roll 100 and the winding roll 103 are driven by a transport device 150. The unwinding roll 104 and the winding roll 111 are driven by a transport device 170. Although detailed illustrations are omitted, in the energy storage device manufacturing apparatus 1, guide rolls 120 are arranged along a predetermined transport path, and the electrode sheet 15 is transported along this transport path. Although not shown in the illustrations, guide rolls, dancer rolls, feed rolls, etc., may be appropriately arranged along the transport path. The transport device 150, the various devices 100-111 incorporated into the energy storage device manufacturing apparatus 1, the transport device 170, etc., are each configured to be controlled by the control device 200.

[0048] In this embodiment, the coating device 102, the first inspection device 105, the second inspection device 107, the half-cutting device 108, the second laser engraving device 110, and the winding roll 111 are each provided with sensors (not shown) for reading the first code 18. A sensor is also attached near the unwinding roll 104, and this sensor is connected to the compression device 106 and the cutting device 109 by wire or wireless connection. This sensor can be implemented, for example, by a camera. Furthermore, the energy storage device manufacturing apparatus 1 includes a winding device (not shown) and an assembly device (not shown) downstream of the winding roll 111. The winding device is a device that winds the positive electrode sheet 21, the negative electrode sheet 22, and the separator sheets 31, 32 (see Figure 2) in layers to create the electrode body 20. The assembly device may also be equipped with a sensor for reading the first code 18. The assembly apparatus is a device for manufacturing a lithium-ion secondary battery 10 by housing the prepared electrode body 20 in a battery case 41 (see Figure 1) and performing procedures such as injecting electrolyte. However, the assembly method using the winding apparatus and assembly apparatus is the same as known technology, so it is omitted from the illustration.

[0049] <Conveying devices 150, 170> The conveying devices 150 and 170 each convey the electrode sheets 15. Although not particularly limited, the conveying speed of the electrode sheets 15 can be set to approximately 10 m / min to 160 m / min in the code application line 1a and the electrode manufacturing line 1b. In this embodiment, motors are used as the conveying devices 150 and 170. The conveying devices 150 and 170 drive the rotation of the unwinding rolls 100 and 104 and the winding rolls 103 and 111 so that the electrode sheets 15 can be conveyed at a predetermined conveying speed. The rotational speeds of the unwinding rolls 100 and 104 and the winding rolls 103 and 111 driven by the conveying device 150 may be controlled by the control device 200. The rotational speeds of the unwinding rolls 100 and 104 and the winding rolls 103 and 111 can be controlled according to a predetermined program so that the conveying speed of the electrode sheets 15 remains constant. The rotational speeds of the unwinding rolls 100, 104 and the winding rolls 103, 111 can be controlled, for example, according to the amount of electrode sheet 15 wound on the unwinding rolls 100, 104 and the winding rolls 103, 111. The energy storage device manufacturing apparatus 1 may also include stepped rollers, etc.

[0050] <First laser engraving device 101> The first laser engraving apparatus 101 is an apparatus for forming a first code 18 on an electrode sheet 15. The first laser engraving apparatus 101 is an example of a first identifier assignment apparatus in the present invention. The first laser engraving apparatus 101 is equipped with a laser emission unit (not shown) and forms a desired first code 18. The first laser engraving apparatus 101 forms a first code 18 having identification information on the electrode sheet 15. Note that the method of assigning a QR code (registered trademark) to the electrode sheet 15 is not limited to engraving with laser light. The apparatus for assigning the first code 18 may, for example, be one that prints a QR code (registered trademark).

[0051] <Coating device 102> The coating apparatus 102 is an apparatus for coating the current collector 16 with an active material layer 17. The coating apparatus 102 is an example of an active material layer forming apparatus in the present invention. The coating apparatus 102 applies the prepared electrode mixture slurry to the current collector 16. When the positive electrode sheet 21 is manufactured in the electrode manufacturing line 1b, the current collector 16 is the positive electrode current collector, and the active material layer 17 is the positive electrode active material layer. When the negative electrode sheet 22 is manufactured in the electrode manufacturing line 1b, the current collector 16 is the negative electrode current collector, and the active material layer 17 is the negative electrode active material layer. Known coating apparatuses can be used to coat the electrode active material layer to the current collector. Examples of coating apparatuses include slit coaters, gravure coaters, die coaters, comma coaters, etc. The current collector 16 can be supported by a backup roll, and the active material layer 17 can be coated on the side opposite to the side supported by the backup roll. The active material layer 17 may be coated on both sides of the current collector 16. The coating apparatus may be equipped with a drying device for drying the active material layer 17 coated on the current collector 16. As the drying device, a device that dries the active material layer 17 using hot air, infrared rays, etc., may be used. In this embodiment, the coating apparatus 102 is configured to read the first code 18 using a sensor and then coat the electrode material slurry. The coating apparatus 102 also links the identification information of the read first code 18 with information on the coating conditions and transmits it to the control device 200. The coating conditions are, for example, the amount of electrode material slurry to be applied.

[0052] <First inspection device 105> The first inspection device 105 is a device that measures the width and inline film thickness of the active material layer 17 coated on the current collector 16 upstream of the compressor 106. In this embodiment, the first inspection device 105 is configured to read the first code 18 using a sensor before performing the measurement. The first inspection device 105 measures the width and film thickness of the portion of the current collector 16 where the active material layer 17 is formed. However, the first inspection device 105 is not particularly limited as long as it can inspect the active material layer 17. In this embodiment, the first inspection device 105 is a device that can measure the width and film thickness without contact. The first inspection device 105 is configured to inspect the active material layer 17 at the same position as the first code 18 in the longitudinal direction of the current collector 16. The first inspection device 105 may measure one location, multiple locations, or the entire width of the electrode sheet 15. The first inspection device 105 links the identification information of the first code 18 with the inspection information and transmits it to the control device 200.

[0053] <Compression device 106> The compression device 106 is a device that compresses the electrode sheet 15 being transported by the transport device 150. The active material layer 17 of the electrode sheet 15 can be compressed vertically by the compression device 106 to adjust it to the required thickness and density. The compression device 106 is configured to read the first code 18 using a sensor located near the unwinding roll 104 and the amount of the electrode sheet 15 being transported. When the transport distance of the first code 18, read by the sensor near the unwinding roll 104, reaches a predetermined distance, the compression device 106 recognizes that the first code 18 has reached the compression device 106. At this time, the compression device 106 acquires identification information of the first code 18 from the sensor. The compression device 106 may also be equipped with an encoder for measuring the transport distance of the electrode sheet 15. The compression device 106 has a pair of rolling rolls 106a and 106b. The electrode sheet 15 is sandwiched between a pair of rolling rolls 106a and 106b. The active material layer 17 is compressed by being rolled through the gap between the pair of rolling rolls 106a and 106b. The pair of rolling rolls 106a and 106b are each connected to a vertically movable press cylinder (not shown). By raising and lowering the press cylinder, the gap between the pair of rolling rolls 106a and 106b is changed. The length of the gap between the pair of rolling rolls 106a and 106b, the linear pressure applied to the electrode sheet 15 by the pair of rolling rolls 106a and 106b, and the speed of the electrode sheet 15 as it passes through the pair of rolling rolls 106a and 106b, i.e., the rotational speed of the pair of rolling rolls 106a and 106b, are controlled by the control device 200. The compression device 106 transmits to the control device 200 the identification information of the read first code 18 and the information of the control conditions described above, linked together.

[0054] <Second inspection device 107> The second inspection device 107 is the same as the first inspection device 105, except that it is located downstream of the compressor 106. A detailed explanation is omitted here. The information obtained from inspecting the active material layer 17 using the first inspection device 105 or the second inspection device 107 will be referred to as inspection information. The first inspection device 105 and the second inspection device 107 are examples of inspection devices in the present invention.

[0055] <Half cutting device 108> The halving device 108 is a device that cuts the electrode sheet 15, which is transported by the conveying device 150, at the center of the electrode sheet 15 in the width direction, and is also called a slitter. The halving device 108 transmits the slit width, which is the length from one end of the electrode sheet 15 to the center in the width direction, to the control device 200. After passing through the cutting device 109, one half of the electrode sheet 15 and the other half are wound onto different winding rolls 111.

[0056] <Cutting device 109> The cutting device 109 is a device that performs tab cutting of the electrode sheet 15 from the front end side in the longitudinal direction of the electrode sheet 15. The cutting device 109 is an example of a tab cutting device in the present invention. In this embodiment, the cutting device 109 performs cutting by laser light. The cutting device 109 is configured to read the first code 18 before performing tab cutting. The method by which the cutting device 109 reads the first code 18 is the same as that of the compression device 106. The cutting device 109 transmits the identification information of the first code 18 along with the conditions for performing tab cutting to the control device 200. The conditions for performing tab cutting are, for example, the degree of output of the laser light. By passing through the cutting device 109, a positive electrode sheet 21 or a negative electrode sheet 22 is generated.

[0057] <Second laser engraving device 110> The second laser marking device 110 is a device that forms a second code 19 on the tab-cut electrode sheet 15. The second laser marking device 110 is an example of a second identifier assignment device. The method by which the second laser marking device 110 assigns the second code 19 is the same as that of the first laser marking device 101, so a detailed explanation is omitted here.

[0058] <Control device 200> The control device 200 may be, for example, a microcomputer. The control device 200 includes, for example, a communication interface, a CPU (Central Processing Unit), ROM (Read Only Memory), and RAM (Random Access Memory). The control device 200 is connected to each device of the energy storage device manufacturing apparatus 1, and is connected to the first laser engraving device 101, the coating device 102, the first inspection device 105, the compression device 106, the second inspection device 107, the halving device 108, the cutting device 109, the second laser engraving device 110, and the conveying device 150, and is configured to control each of them.

[0059] The control device 200 has a recording device 210. The recording device 210 is a device that records the identification information of the first code 18 and the inspection information linked together. The recording device 210 also stores the identification information of the second code 19 and the position on the current collector 16 where the second code 19 is assigned, linked together. The recording device 210 is a device that records information such as that of a hard disk drive. The recording device 210 records the information linked to the identification information of the first code 18 transmitted from each device connected to the control device 200, for each piece of identification information, and builds a database. Figure 6 is a diagram showing an example of the database DT built by the recording device 210. The configuration of the recording device 210 is not particularly limited. The recording device 210 may be an external server device such as a cloud server.

[0060] The manufacturing apparatus 1 for the electrode sheet 15 has been described above. Next, the manufacturing method for the lithium-ion secondary battery 10 will be described. Figure 7 is a flow chart showing the manufacturing method for the lithium-ion secondary battery 10. The manufacturing method for the lithium-ion secondary battery 10 disclosed herein includes a first identifier assignment step S1, a coating step S2, a first inspection step S3, a compression step S4, a second inspection step S5, a halving step S6, a tab cutting step S7, a second identifier assignment step S8, a winding step S9, and an assembly step S10.

[0061] In the first identifier assignment step S1, a first code 18 is assigned to the electrode sheet 15 unwound from the unwinding roll 100. The first code 18 is formed by the first laser marking device 101. When the first laser marking device 101 forms the first code 18, it assigns identification information to the first code 18. At this time, the control device 200 records the identification information in the database DT of the recording device 210.

[0062] In the coating process S2 shown in Figure 7, the coating device 102 forms an active material layer 17 on the current collector 16. The coating device 102 reads the first code 18, identifies its location, and applies the electrode mixture slurry. The coating conditions at this time are controlled by the control device 200. The coating device 102 links the identification information of the first code 18 with the coating conditions at that location and transmits it to the control device 200. The control device 200 records the coating conditions linked to the identification information of the first code 18 recorded in the database DT (see Figure 6).

[0063] After the coating process S2, the electrode sheet 15 is wound onto the winding roll 103 and moved to the unwinding roll 104. The method of moving the electrode sheet 15 wound onto the winding roll 103 is not particularly limited, but for example, it may be carried to the unwinding roll 104 by an operator. The carried electrode sheet 15 is then unwound from the unwinding roll 104.

[0064] In the first inspection step S3, the position of the strip-shaped current collector 16 is identified in association with the first code 18, and inspection information of the state of the active material layer 17 is recorded. In this embodiment, the width and inline thickness of the active material layer 17 are measured by the first inspection device 105, and the width and inline thickness of the active material layer 17 at the longitudinal position to which the first code 18 is assigned are sent to the control device 200 in association with the identification information of the first code 18. The control device 200 is configured to record the width and inline thickness of the active material layer 17 at the longitudinal position to which the first code 18 is assigned in the database DT in association with the identification information of the first code 18.

[0065] In the compression process S4, the active material layer 17 is compressed by the compression device 106. The compression device 106 reads the identification information of the first code 18 at the location to be compressed before compressing. After the first code 18 is read by a sensor located near the unwinding roll 104, the compression device 106 recognizes that the amount of electrode sheet 15 being transported has reached a predetermined distance and obtains the identification information of the first code 18 from the sensor. The compression device 106 compresses the rolling rolls 106a and 106b under predetermined conditions. The compression device 106 links the identification information of the read first code 18 with the compression conditions at that location and transmits it to the control device 200. The compression device 106 transmits, for example, the value of the linear pressure to the control device 200.

[0066] In the second inspection step S5, the position of the strip-shaped current collector 16 is identified in association with the first code 18, and inspection information of the state of the active material layer 17 is recorded. In this embodiment, the width and inline thickness of the active material layer 17 are measured by the second inspection device 107, and the width and inline thickness of the active material layer 17 at the longitudinal position to which the first code 18 is assigned are sent to the control device 200 in association with the identification information of the first code 18. The control device 200 is configured to record the width and inline thickness of the active material layer 17 at the longitudinal position to which the first code 18 is assigned in the database DT in association with the identification information of the first code 18.

[0067] In the half-cutting process S6, the electrode sheet 15 is cut in the center in the width direction by the half-cutting device 108. At this time, the half-cutting device 108 transmits the slit width conditions to the control device 200.

[0068] In the tab-cutting process S7, the cutting device 109 performs tab cutting on the electrode sheet 15. The cutting device 109 reads the identification information of the first code 18 engraved on the tab-forming region 16aa to be tab-cut, and performs tab cutting while identifying its position. That is, tab cutting is performed while identifying the longitudinal position on the electrode sheet 15. The method by which the cutting device 109 obtains the identification information of the first code 18 is the same as in the compression process S4. The cutting device 109 links the read identification information of the first code 18 with the cutting conditions and transmits it to the control device 200. The cutting conditions include, for example, the degree of laser light output during tab cutting. The code-engraved region 16ab is cut off and discarded by the tab-cutting process.

[0069] In the second identifier assignment step S8, a second code 19 is assigned to the tab formed in the tab cutting process S7. If the sheet being formed is the positive electrode sheet 21, the second code 19 is assigned to tab 21t (see Figure 2). If the sheet being formed is the negative electrode sheet 22, the second code 19 is assigned to the location corresponding to tab 22t (see Figure 2). The method for assigning the second code 19 is, for example, by laser light, similar to the first code 18. The database DT stores the identification information of the second code 19 and its position on the current collector 16, linked together. For example, the identification number and the distance from the front end of the current collector 16 in the longitudinal direction to the second code 19 are stored together.

[0070] In the winding process S9, as shown in Figure 3, the tab-cut positive electrode sheet 21 and the negative electrode sheet 22 are overlapped and wound together with separator sheets 31 and 32 in between. This creates the electrode body 20. At this time, it is preferable that the winding device reads the second code 19 formed on the tab 21t of the positive electrode sheet 21 and the tab 22t of the negative electrode sheet 22. This allows inspection information of the active material layer 17 along the longitudinal direction of the positive electrode sheet 21 and the negative electrode sheet 22 contained in the electrode body 20 to be acquired retrospectively through the second code 19, even after the winding process S9.

[0071] In the assembly process S10 shown in Figure 7, the electrode body 20 is housed and sealed in the battery case 41 by a known method. Furthermore, the assembly process S10 is preferably configured to allow the reading of a unique number assigned to the battery case 41. The read unique number is sent to the control device 200. The control device 200 is configured to associate this unique number with the second code 19 contained in the electrode body 20 housed in the battery case 41 and record this information in the database DT. The assembly device associates the unique number with the identification number of the second code 19 and houses the electrode body 20 in the battery case 41. Once the electrode body 20 is housed and sealed in the battery case 41, electrolyte injection, initial charging, and aging processes are performed. Here, during electrolyte injection and initial charging, the amount of electrolyte to be injected and the initial charging time are calculated based on the information recorded in the database DT in association with the identification information of the first code 18. For example, if the measured film thickness is relatively large, the amount of electrolyte that the electrode body 20 can absorb increases, so the amount of electrolyte injected is increased. Also, for example, if the film density is relatively large, the electrode body 20 becomes less able to absorb the electrolyte, so the amount of electrolyte injected is increased. The amount of electrolyte injected may be determined by the operator while looking at the inspection information in the database DT, or it may be automatically calculated by the control device 200 using the inspection information in the database DT. The aging process can be performed by known methods.

[0072] The manufacturing flow for the lithium-ion secondary battery 10 is not limited to the order described above. For example, the electrode sheet 15 may be wound up after the halving process but before the tab cutting process. In this case, the tab cutting process and the application of the second code 19 are performed while the halved electrode sheet 15 is being unwound, and the assembly process is then carried out.

[0073] Furthermore, the location where the second code 19 is applied is not limited to tabs 21t and 22t. The second code 19 may be applied to the outer portion of the wound electrode body 20. Alternatively, the second code 19 may be applied to the outside when the lithium-ion secondary battery 10 is assembled.

[0074] As described above, in the embodiment described above, the first code 18 is formed at equal intervals along the length of the current collector 16 in the unformed region 16a. In the first inspection step S3 and the second inspection step S5, the inspection information of the active material layer 17 is recorded in the recording device 210 while the position in the length of the current collector 16 is identified by the first code 18. As a result, the database DT of the recording device 210 records the inspection information of the active material layer 17 at each position of the current collector 16, linked to identification information. It is possible to retrospectively identify the inspection information of the active material layer 17 corresponding to the position to which the first code 18 is attached, making it possible to predict or retrospectively understand individual differences in the electrode material used in the cell.

[0075] In the embodiment described above, the identification information of the first code 18 is obtained using a sensor provided near the unwinding roll 104 and the amount of the electrode sheet 15 being transported, and then tab cutting is performed. The second code 19 is attached to predetermined positions on the tabs 21t and 22t formed by the tab cutting process. In this case, information linked to the first code 18 can be obtained through the identification information of the second code 19. Therefore, inspection information of the active material layer 17 along the longitudinal direction of the positive electrode sheet 21 and negative electrode sheet 22 after tab cutting can be obtained retrospectively through the identification information of the second code 19.

[0076] Note that the second code 19 may be assigned before tab cutting. Figure 8 is a flowchart showing a method for manufacturing a lithium-ion secondary battery 10 in a different order than the flowchart shown in Figure 7. Steps S1 to S6, S9 and S10 are the same as in the flowchart shown in Figure 7. As shown in Figure 8, the second identifier assignment step S8 may be performed before the tab cutting process step S7. That is, after the second code 19 is assigned, tabs 21t and 22t are formed by the tab cutting process. At this time, it is preferable to read the first code 18 and the second code 19 and associate and store them in accordance with their positions along the longitudinal direction of the positive electrode sheet 21 and the negative electrode sheet 22. In this case as well, after tab cutting is performed, inspection information of the active material layer 17 along the longitudinal direction of the positive electrode sheet 21 and the negative electrode sheet 22 after tab cutting, which is associated with the first code 18, can be obtained through the identification information of the second code 19.

[0077] The above-described embodiment further includes a winding step in which the tab-cut positive electrode sheet 21 and negative electrode sheet 22 are wound up while reading the second code 19. In this case, inspection information of the active material layer 17 corresponding to the position where the first code 18 was attached to the long, strip-shaped positive electrode sheet 21 and negative electrode sheet 22 can be obtained from the electrode body 20 through the identification information of the second code 19. Therefore, inspection information of the active material layer 17 along the length direction of the positive electrode sheet 21 and negative electrode sheet 22 contained in the electrode body 20 can be obtained retrospectively.

[0078] In the embodiment described above, the process further includes the steps of housing the wound electrode body 20 in the battery case 41, obtaining a unique number assigned to the battery case 41, and recording the unique number and the second code 19 of the electrode body 20 housed in the battery case 41 in the recording device 210. In this case, identification information of the second code 19 of the electrode body 20 housed in the battery case 41 can be obtained through the unique number of the battery case 41. Furthermore, inspection information of the active material layer 17 corresponding to the position where the first code 18 was attached to the long, strip-shaped positive electrode sheet 21 and negative electrode sheet 22 can be obtained through the identification information of the second code 19. For this reason, after the electrode body 20 is housed in the battery case 41, inspection information of the active material layer 17 along the length direction of the positive electrode sheet 21 and negative electrode sheet 22 contained in the electrode body 20 housed in the battery case 41 can be obtained through the unique number of the battery case 41.

[0079] The above-described embodiment further includes the steps of housing the wound electrode body 20 in the battery case 41 and determining the amount of electrolyte to be injected and the initial charging time based on the information recorded in association with the identification information of the first code 18. For example, the required amount of electrolyte and the optimal length of the initial charging time change depending on the thickness of the film thickness formed on the electrode body 20 during coating. By determining the amount of electrolyte and the length of the initial charging time based on the information recorded in association with the identification information of the first code 18, the quality of the manufactured lithium-ion secondary battery 10 can be maintained.

[0080] In the embodiment described above, the database DT of the recording device 210 records the identification information of the first code 18 and the inspection results performed by the first inspection device 105 and the second inspection device 107 in association with each other. By reading the first code 18, the positions of the positive electrode current collector 21a and the negative electrode current collector 22a used in the electrode body 20 can be identified on the current collector 16, and inspection information of the active material layer 17 at those positions can be obtained.

[0081] In the embodiment described above, the second code 19 is formed on tabs 21t and 22t. The second code 19 has identification information. The identification information of the second code 19 is recorded in the database DT of the recording device 210. By reading the second code 19 when the electrode body 20 is formed, the position of the active material layer 17 contained in the electrode body 20 on the current collector 16 can be verified. By verifying the position of the active material layer 17 contained in the electrode body 20, inspection information of the active material layer 17 at that position can be obtained.

[0082] In the embodiment described above, the database DT of the recording device 210 records the identification information of the second code 19 and the inspection information of the active material layer 17 at that location, linked together. Furthermore, the tabs 21t and 22t on which the second code 19 is formed are different from the code marking area 16ab and are part of the electrode body 20. Therefore, by reading the second code 19 contained in the electrode body 20, it is possible to identify the positions of the positive electrode current collector 21a and the negative electrode current collector 22a used in the electrode body 20 on the current collector 16, and to obtain inspection information of the active material layer 17 at that location. For example, the inspection information can be used to estimate the amount of electrolyte to be injected into the lithium-ion secondary battery 10 and the initial charging time.

[0083] In the embodiment described above, the identification number of the second code 19 and the unique number of the battery case 41 are linked and recorded in the database DT of the recording device 210. Therefore, by reading the unique number of the battery case 41, the electrode body 20 housed in the battery case 41 can be identified.

[0084] In the embodiment described above, the database DT of the recording device 210 stores the identification number of the second code 19, the position of the current collector, and the inspection information of the active material layer 17 at that position, linked together. Therefore, by reading the unique number of the battery case 41, the identification number linked to that unique number can be identified, and from the identified identification number, the position of the strip-shaped current collector 16 and the inspection information of the active material layer 17 at that position can be further identified.

[0085] In the embodiment described above, the battery case 41 was assigned a unique number, but this is not the only possible configuration. The unique number may be assigned to the sealing plate 41b. In this case, as in the embodiment described above, the unique number and the second code 19 are linked and recorded in the recording device 210. Therefore, the identification information of the second code 19 of the electrode body 20 can be obtained through the unique number of the sealing plate 41b. Furthermore, the inspection information of the active material layer 17 corresponding to the position where the first code 18 was assigned to the elongated strip-shaped positive electrode sheet 21 and negative electrode sheet 22 can be obtained through the identification information of the second code 19. For this reason, after the electrode body 20 is housed in the battery case 41, the inspection information of the active material layer 17 along the length direction of the positive electrode sheet 21 and negative electrode sheet 22 contained in the electrode body 20 housed in the battery case 41 can be obtained through the unique number of the sealing plate 41b.

[0086] The inspection information included in the database DT described above is not limited to that mentioned above. The information included in database DT may include, for example, information such as the specific gravity of the electrode material slurry and the width to be applied. Database DT may also include the lot number of the current collector 16 used.

[0087] In the embodiments described above, the electrode sheet 15 had a first code 18 and a second code 19 formed on it, but it is not limited to this. The electrode sheet 15 may have only one of the first code 18 and the second code 19 formed on it.

[0088] Furthermore, in the configuration shown in Figure 5, the energy storage device manufacturing apparatus 1 is equipped with a first inspection device 105 and a second inspection device 107 before and after (upstream and downstream of) the compressor 106, respectively, but the apparatus is not limited to this configuration. For example, the inspection device may inspect the active material layer 17 after it has been compressed by the compressor 106. In other words, the energy storage device manufacturing apparatus 1 may not have a first inspection device 105, but may have a second inspection device 107.

[0089] The invention disclosed herein has been described in various ways. Unless otherwise specified, the embodiments and other details described herein do not limit the present invention. Furthermore, the embodiments of the invention disclosed herein can be modified in various ways, and each component and each process mentioned herein may be omitted or combined as appropriate, unless no particular problems arise.

[0090] In the embodiment described above, the identification information of the first code 18 was obtained using a sensor provided near the unwinding roll 104 and the amount of electrode sheet 15 being transported. However, the cutting device 109 may also be equipped with a sensor to read the first code 18. Tab cutting is performed while the electrode sheet 15 is being transported. In some cases, the electrode sheet 15 may break during tab cutting. At this time, the pass line is set while the electrode sheet 15 is transported at a relatively low speed. In order to determine the position of the electrode sheet 15 when setting the pass line, the first code 18 may be read using a sensor provided in the cutting device 109.

[0091] As described above, this specification includes the disclosures set forth in the following sections.

[0092] Section 1: A step of attaching a first identifier to a predetermined unformed region along the length of a strip-shaped current collector at predetermined intervals to identify the position on the strip-shaped current collector, A step of forming an active material layer in the portion of the strip-shaped current collector excluding the unformed region, An inspection step in which the position of the strip-shaped current collector is identified in association with the first identifier, and inspection information is recorded in which the state of the active material layer is inspected, A method for manufacturing an energy storage device, including [the specified element].

[0093] Section 2: A tab-cutting process involves reading the first identifier of the strip-shaped current collector, identifying the position of the strip-shaped current collector, and performing a tab cut in the unformed region; A step of attaching a second identifier to a predetermined position on the tab formed in the tab cutting process, A method for manufacturing an energy storage device according to claim 1, including the following:

[0094] Section 3: A second identifier assignment step involves assigning a second identifier to the region in the aforementioned unformed region where a tab is formed by tab cutting, A tab-cutting process is performed on the unformed region to which the second identifier has been assigned, A method for manufacturing an energy storage device according to claim 1, including the following: Section 4: A method for manufacturing an energy storage device according to claim 2 or 3, further comprising a winding step of reading the second identifier and winding the strip-shaped current collector that has undergone the tab-cutting process.

[0095] Section 5: The process of reading the second identifier of the electrode body obtained in the winding process and housing the electrode body in the battery case, A step of obtaining a unique number attached to the battery case, A step of recording the unique number of the battery case and the second identifier of the electrode body housed in the battery case, linked together. A method for manufacturing an energy storage device according to claim 4, including the following:

[0096] Item 6: The process of reading the second identifier of the electrode body obtained in the winding process and housing the electrode body in a battery case having an opening, The process involves sealing the opening with a sealing plate that has been assigned a unique number, A step of obtaining a unique number attached to the sealing plate, A step of recording the unique number of the sealing plate and the second identifier of the electrode body housed in the sealing plate, linked together. A method for manufacturing an energy storage device according to claim 4, including the following:

[0097] Section 7: The process of reading the second identifier of the electrode body obtained in the winding process and housing the electrode body in the battery case, A step of determining the amount of electrolyte to be injected and the initial charging time based on the information recorded in association with the first identifier. A method for manufacturing an energy storage device according to claim 4, including the method described in claim 4.

[0098] Section 8: A strip-shaped current collector has a predetermined unformed region along its length, and a first identifier for identifying the position on the strip-shaped current collector is provided at predetermined intervals. While identifying the position of the strip-shaped current collector in association with the first identifier, the inspection information of the active material layer formed on the strip-shaped current collector and A recording device configured to record data in a linked manner.

[0099] Section 9: The recording device according to claim 8, wherein a second identifier attached to a predetermined position on a tab formed in the unformed region of the strip-shaped current collector and the position of the strip-shaped current collector to which the second identifier is attached are further linked and recorded.

[0100] Section 10: The recording device according to claim 9, configured to acquire, based on the second identifier, the strip-shaped current collector and inspection information of the active material layer at a position along the longitudinal direction of the current collector.

[0101] Section 11: A second identifier is assigned to the tab of the electrode body made from the aforementioned strip-shaped current collector, The unique number assigned to the battery case in which the electrode body is housed, and The recording device according to claim 8, configured to further link and record the data.

[0102] Section 12: The recording device according to claim 11, configured to acquire, based on the unique number of the battery case, the position of the strip-shaped current collector used in the electrode body housed in the battery case, and inspection information of the active material layer at that position.

[0103] Section 13: A first identifier assigning device that assigns a first identifier to a strip-shaped current collector at predetermined intervals to an unformed region set in advance along the length direction, for the purpose of identifying the position on the strip-shaped current collector, An active material layer forming apparatus for forming an active material layer in the portion of the strip-shaped current collector excluding the unformed region, An inspection device that identifies the position of the strip-shaped current collector in association with the first identifier, and inspects the state of the active material layer, A recording device for recording inspection information obtained by the aforementioned inspection device, A device for manufacturing energy storage devices, equipped with the following features.

[0104] Section 14: A tab-cutting device that reads the first identifier of the strip-shaped current collector, identifies the position of the strip-shaped current collector, and performs a tab cut in the unformed region, A second identifier assigning device that assigns a second identifier to a predetermined position on a tab formed by the tab cutting device, and An apparatus for manufacturing an energy storage device according to claim 13, further comprising the above.

[0105] Section 15: A second identifier assigning device that assigns a second identifier to the region in the aforementioned unformed region where a tab is formed by tab cutting, A tab cutting device that performs the tab cutting on the unformed region to which the second identifier has been assigned by the second identifier assigning device, and An apparatus for manufacturing an energy storage device according to claim 13, further comprising the above.

[0106] Section 16: An apparatus for manufacturing an energy storage device according to claim 14 or 15, further comprising a winding device for reading the second identifier and winding up the strip-shaped current collector on which the tab cut has been performed.

[0107] Section 17: The energy storage device manufacturing apparatus according to claim 16, further comprising an assembly apparatus for housing the electrode body in the battery case, which associates the second identifier of the electrode body created by the winding apparatus with a unique number assigned to the battery case housing the electrode body.

[0108] Section 18: An assembly device that reads the second identifier of the electrode body created by the winding device, houses the electrode body in a battery case having an opening, and seals the opening with a sealing plate bearing a unique number, A recording device that records the unique number of the sealing plate and the second identifier of the electrode body housed in the sealing plate, linking them together. An apparatus for manufacturing an energy storage device according to claim 16, further comprising the above.

[0109] Section 19: An assembly device that reads the second identifier of the electrode body created by the winding device and houses the electrode body in a battery case, A control device that determines the amount of electrolyte to be injected and the initial charging time based on information recorded in association with the first identifier, An apparatus for manufacturing an energy storage device according to claim 16, further comprising: [Explanation of Symbols]

[0110] 1. Energy storage device manufacturing equipment 1a Code assignment line 1b Electrode manufacturing line 10. Lithium-ion secondary batteries (energy storage devices) 15 electrode sheets 16 Current collector 16a Unformed area 16aa Tab-forming region 16ab Code engraving area 17 Active material layer 18. First Code (First Identifier) 19. Second Code (Second Identifier) 20 Electrode body 21 Positive electrode sheet 21a Positive electrode current collector 21a1 Unformed part 21b Positive electrode active material layer 21p positive electrode protective layer 21t positive electrode tab 22 Negative electrode sheets 22a Negative electrode current collector 22a1 Unformed part 22b Negative electrode active material layer 22p negative electrode protective layer 22t negative electrode tab 31, 32 Separator Sheets 41 Battery case 41a Case body 41a1 opening 41b Sealing plate 41b1 Liquid injection hole 41b2 Sealing member 41b3 Safety valve 42 Bottom part 43,44 Wide surface section 45, 46 Narrow side part 50 Positive terminal 51, 61 External terminals 55, 65 Internal terminal 60 Negative terminal 61 External terminals 70 Gasket 80 Insulators 100, 104 unwinding rolls 101 Laser Engraving Machine 102 Coating apparatus 103, 111 Reel roll 106 Compressor 106a, 106b Rolling Rolls 108 Half cutting device 109 Cutting device 110 Laser engraving machine 120 rolls 150 Conveying device 200 Control device 210 Recording device CL cutting line DT Database S1 First identifier assignment process S2 Coating process S3 First Inspection Process S4 Compression Process S5 Second Inspection Process S6 Half cutting process S7 Tab cutting process S8 Second Identifier Assignment Process S9 Winding process S10 Assembly Process

Claims

1. A step of pre-setting an unformed region having a tab-forming region and a code-marking region along the length of a strip-shaped current collector, A step of attaching a first identifier for identifying the position of the strip-shaped current collector to the code marking area at predetermined intervals, A step of forming an active material layer in the portion of the strip-shaped current collector excluding the unformed region, An inspection step of recording inspection information obtained by identifying the position of the strip-shaped current collector in association with the first identifier, and inspecting the state of the active material layer, including the thickness of the active material layer, A sheet manufacturing step involves cutting off the code-marked area to which the first identifier is assigned from the unformed area, and attaching a second identifier having information linked to the first identifier to the tab-forming area, thereby producing an electrode sheet having multiple tabs to which the second identifier is assigned; A method for manufacturing an energy storage device, including [the specified element].

2. The aforementioned sheet manufacturing process is as follows: A tab-cutting process is performed to cut off the code-marked area by reading the first identifier of the strip-shaped current collector, identifying the position of the strip-shaped current collector, and performing a tab cut in the unformed area. A step of attaching the second identifier to a predetermined position on the tab formed in the tab cutting process, A method for manufacturing an energy storage device according to claim 1, including the method described in claim 1.

3. The aforementioned sheet manufacturing process is as follows: A second identifier assignment step involves assigning the second identifier to the tab-forming region in which a tab is formed by tab cutting, among the unformed region; A tab-cutting process is performed on the unformed region to which the second identifier has been assigned, thereby cutting off the code-marked region. A method for manufacturing an energy storage device according to claim 1, including the following:

4. A method for manufacturing an energy storage device according to claim 1, further comprising a winding step of manufacturing an electrode body by winding the electrode sheet while reading the second identifier in each of the plurality of tabs.

5. The process of reading the second identifier of the electrode body obtained in the winding process and housing the electrode body in the battery case, A step of obtaining a unique number attached to the battery case, A step of recording the unique number of the battery case and the second identifier of the electrode body housed in the battery case, linked together. A method for manufacturing an energy storage device according to claim 4, including the following:

6. The process of reading the second identifier of the electrode body obtained in the winding process and housing the electrode body in a battery case having an opening, The process involves sealing the opening with a sealing plate that has been assigned a unique number, A step of obtaining a unique number attached to the sealing plate, A step of recording the unique number of the sealing plate and the second identifier of the electrode body housed in the sealing plate, linked together. A method for manufacturing an energy storage device according to claim 4, including the following:

7. The process of reading the second identifier of the electrode body obtained in the winding process and housing the electrode body in the battery case, A step of determining the amount of electrolyte to be injected and the initial charging time based on the information recorded in association with the first identifier. A method for manufacturing an energy storage device according to claim 4, including the method described in claim 4.

8. A first storage means stores identification information of a first identifier that is attached to a pre-set unformed region along the length of a strip-shaped current collector and identifies the position on the strip-shaped current collector at predetermined intervals, A second storage means stores inspection information, including the film thickness of the active material layer formed on the strip-shaped current collector, while identifying the position of the strip-shaped current collector in association with the first identifier, A first linking means for recording the identification information of the first identifier and the inspection information in a linked manner, A third storage means is attached to a predetermined position on a tab formed in the unformed region of the strip-shaped current collector and stores identification information of a second identifier that identifies the position of the tab, A first linking means for recording the identification information of the first identifier, the inspection information, and the identification information of the second identifier in a linked manner, A recording device equipped with this device.

9. The recording device according to claim 8, wherein a second identifier attached to a predetermined position on a tab formed in the unformed region of the strip-shaped current collector and the position of the strip-shaped current collector to which the second identifier is attached are further linked and recorded.

10. The recording device according to claim 9, configured to acquire, based on the second identifier, the strip-shaped current collector and inspection information of the active material layer at a position along the longitudinal direction of the current collector.

11. A second identifier is assigned to the tab of the electrode body made from the aforementioned strip-shaped current collector, The unique number assigned to the battery case in which the electrode body is housed, and The recording device according to claim 8, configured to further link and record the data.

12. The recording device according to claim 11, configured to acquire, based on the unique number of the battery case, the position of the strip-shaped current collector used in the electrode body housed in the battery case, and inspection information of the active material layer at that position.

13. A setting device for pre-setting an unformed region having a tab-forming region and a code-marking region along the length of a strip-shaped current collector, A first identifier assigning device that assigns a first identifier for identifying the position of the strip-shaped current collector to the code marking area at predetermined intervals, An active material layer forming apparatus for forming an active material layer in the portion of the strip-shaped current collector excluding the unformed region, An inspection device that identifies the position of the strip-shaped current collector in association with the first identifier, and inspects the state of the active material layer, including the thickness of the active material layer, A recording device for recording inspection information obtained by the aforementioned inspection device, A tab-cutting device that cuts off the code-marked area to which the first identifier is assigned from the unformed area, A second identifier assigning device that assigns a second identifier having information associated with the first identifier to the tab forming region, thereby producing an electrode sheet having a plurality of tabs to which the second identifier is attached, A device for manufacturing energy storage devices, equipped with the following features.

14. The tab-cutting device reads the first identifier of the strip-shaped current collector, identifies the position of the strip-shaped current collector, and cuts off the code-marked area by performing a tab cut in the unformed area. The energy storage device manufacturing apparatus according to claim 13, wherein the second identifier assigning device assigns the second identifier to a predetermined position on the tab formed by the tab cutting device.

15. The second identifier assigns a second identifier to the tab-forming region in the unformed region where tabs are formed by tab cutting. The energy storage device manufacturing apparatus according to claim 13, wherein the tab cutting device cuts off the code-marked area by performing the tab cutting on the unformed area to which the second identifier has been assigned by the second identifier assigning device.

16. The energy storage device manufacturing apparatus according to claim 13, further comprising a winding device for manufacturing an electrode body by winding the electrode sheet while reading the second identifier in each of the plurality of tabs.

17. The energy storage device manufacturing apparatus according to claim 16, further comprising an assembly apparatus for housing the electrode body in the battery case, which links the second identifier of the electrode body created by the winding apparatus with a unique number assigned to the battery case housing the electrode body.

18. An assembly device that reads the second identifier of the electrode body created by the winding device, houses the electrode body in a battery case having an opening, and seals the opening with a sealing plate bearing a unique number, A recording device that records the unique number of the sealing plate and the second identifier of the electrode body housed in the sealing plate, linking them together. An apparatus for manufacturing an energy storage device according to claim 16, further comprising the above.

19. An assembly device that reads the second identifier of the electrode body created by the winding device and houses the electrode body in a battery case, A control device that determines the amount of electrolyte to be injected and the initial charging time based on information recorded in association with the first identifier, An apparatus for manufacturing an energy storage device according to claim 16, further comprising:

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