Apparatus and method for forming a converged portion

Abstract

To provide a molding device of a current collecting bundle part capable of properly suppressing deformation of an electrode group structure and properly inserting a binding tool into an internal space of the electrode group structure.SOLUTION: In an embodiment, there is provided a forming device for forming a current collector bundling part in which a plurality of current collector band parts are bundled in a projecting part of a current collector in an electrode group structure in which the current collector projects, and the forming device includes a holding jig and a binding jig. The pressing jig abuts on the electrode group structure from the inner peripheral side in the internal space of the electrode group structure to press the innermost peripheral sheet portion of the electrode group structure from the inner peripheral side. The binding jig is used to form the current collector bundle portion, and is inserted into the internal space of the electrode group structure in a state where the innermost peripheral sheet portion is pressed by the pressing jig.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] An embodiment of the present invention relates to a molding device and a molding method for a current collecting bundle portion. [Background technology]

[0002] The electrode group of a battery includes a positive electrode and a negative electrode as electrodes, and the current collectors of the electrodes protrude from the electrode group. Furthermore, in the electrode group, a current collecting bundle portion bundling a plurality of current collecting band portions is formed on the protruding portion of the current collector. In a battery or the like, the current collecting bundle portion is electrically connected to a terminal via a conductive member such as a lead.

[0003] In manufacturing an electrode assembly, for example, an electrode assembly is formed by winding a stacked structure in which two electrode sheets (a positive electrode sheet and a negative electrode sheet) and two separator sheets are stacked. At this time, the electrode assembly is formed in a state in which the current collectors of the electrode sheets protrude in the axial direction (length direction) along the winding axis. In manufacturing an electrode assembly, after forming the electrode assembly, pressure is applied to the electrode assembly using a press or the like to compress the electrode assembly in the thickness direction. In parallel with the application of pressure to the electrode assembly, a bundling jig presses the protruding portions of the current collectors from within the internal space of the electrode assembly, thereby bundling multiple current collecting band portions and forming current collecting bundle portions for each of the electrodes (positive and negative electrodes). The bundling jig used to form the current collecting bundle portions is inserted into the internal space after the electrode assembly is formed and before pressure is applied to the electrode assembly.

[0004] In the manufacture of an electrode group, during the process from the formation of the electrode group structure to the start of forming the current collecting bundle part, loosening occurs in the wound portion of the electrode group structure due to temporary pressing, preheating, transportation, etc. For this reason, the innermost peripheral sheet portion of the electrode group structure is prone to slippage just before the start of forming the current collecting bundle part, and the electrode group structure is prone to deformation due to the slippage of the innermost peripheral sheet portion. In the manufacture of an electrode group, from the viewpoint of properly forming the current collecting bundle part, etc., it is required to appropriately suppress deformation of the electrode group structure, such as at the stage just before the start of forming the current collecting bundle part, and to properly insert a binding jig into the internal space. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-120281 Summary of the Invention [Problem to be solved by the invention]

[0006] The problem that the present invention aims to solve is to provide a molding device and molding method for a current collecting bundle portion that appropriately suppresses deformation of the electrode group structure and enables a binding jig to be appropriately inserted into the internal space of the electrode group structure. [Means for solving the problem]

[0007] According to an embodiment, there is provided a molding device for molding a current collecting bundle portion in which a plurality of current collecting band portions are bundled around a protruding portion of an electrode group structure having a protruding current collector, the molding device including a pressing jig and a bundling jig. The pressing jig abuts against the electrode group structure from the inner periphery side in the internal space of the electrode group structure, thereby pressing down the innermost sheet portion of the electrode group structure from the inner periphery side. The bundling jig is used to form the current collecting bundle portion and is inserted into the internal space of the electrode group structure with the innermost sheet portion being pressed down by the pressing jig. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view schematically showing an example of an electrode group produced in an embodiment. [Figure 2] FIG. 2 is a cross-sectional view schematically showing the example electrode group of FIG. 1 in a cross section perpendicular or substantially perpendicular to the width direction. [Figure 3] FIG. 3 is a perspective view illustrating an example of a process for forming an electrode group structure in the embodiment. [Figure 4] FIG. 4 is a block diagram showing an example of the configuration of a forming device that performs processing related to the formation of the current collecting bundle portion on the electrode group structure in the embodiment. [Figure 5] FIG. 5 is a cross-sectional view schematically showing an example of an electrode group structure immediately before the start of forming of the current collecting bundle portion in an embodiment, in a cross section perpendicular or substantially perpendicular to the length direction (axial direction). [Figure 6] FIG. 6 is a flowchart schematically illustrating an example of processing performed in the control unit and the like of the molding device in the embodiment. [Figure 7] FIG. 7 is a schematic diagram showing an example of the change in state of the electrode group structure and its vicinity from when the electrode group structure is transported to the molding device until just before the pressure section starts applying pressure to the electrode group structure in the embodiment. [Figure 8] FIG. 8 is a cross-sectional view that schematically shows the state α4 of the example of FIG. 7 in a cross section perpendicular or substantially perpendicular to the longitudinal direction of the electrode group structure. [Figure 9] Figure 9 is a cross-sectional view schematically showing an example of a state in an embodiment immediately after the pressure applying unit starts applying pressure to the electrode group structure after state α5 in Figure 7, in a cross-section perpendicular or approximately perpendicular to the width direction of the electrode group structure. [Figure 10] FIG. 10 is a cross-sectional view schematically showing an example of a state in which a current collecting bundle portion is formed using a bundling jig after the state of FIG. 9 in an embodiment, in a cross section perpendicular or approximately perpendicular to the width direction of the electrode group structure. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described with reference to the drawings.

[0010] The present embodiment relates to an electrode group used in a battery or the like, and particularly to a manufacturing process for the electrode group. FIGS. 1 and 2 schematically show an example of an electrode group 1 manufactured in the embodiment. As shown in FIGS. 1 and 2, the electrode group 1 has a length direction (direction indicated by arrow L), a width direction (direction indicated by arrow W) that intersects (orthogonal or approximately orthogonal to) the length direction, and a thickness direction (direction indicated by arrow T) that intersects (orthogonal or approximately orthogonal to) both the length direction and the width direction. The dimension of the electrode group 1 along the thickness direction is smaller than the dimension of the electrode group 1 along the length direction and the dimension of the electrode group 1 along the width direction. Note that FIG. 1 shows a perspective view, and FIG. 2 shows a cross section that is orthogonal or approximately orthogonal to the width direction.

[0011] The electrode group 1 includes a pair of electrodes, a positive electrode and a negative electrode. In the electrode group 1, the positive electrode and the negative electrode have opposite polarities. In addition, in the electrode group 1, a separator is interposed between the positive electrode and the negative electrode. In the electrode group 1, the separator is made of an electrically insulating material and electrically insulates the positive electrode from the negative electrode.

[0012] In the electrode group 1, each of the electrodes (positive electrode and negative electrode) includes a current collector such as a current collector foil, and an active material-containing layer coated (supported) on the surface of the current collector. In each of the electrodes, the active material-containing layer may be coated on only one side of the current collector, or may be coated on both sides of the current collector. In addition, in the electrode group 1, the current collector of each of the electrodes (positive electrode and negative electrode) includes an uncoated portion 11 where the active material-containing layer is not coated (supported). In the uncoated portion 11, the active material-containing layer is not coated on either side of the current collector. In the following description, the positive electrode current collector, active material-containing layer, and uncoated portion 11 will also be referred to as the "positive electrode current collector," the "positive electrode active material-containing layer," and the "positive electrode uncoated portion," respectively. The negative electrode current collector, active material-containing layer, and uncoated portion 11 are also referred to as the "negative electrode current collector," the "negative electrode active material-containing layer," and the "negative electrode uncoated portion," respectively.

[0013] In the example shown in Figures 1 and 2, in the electrode group 1, the uncoated portions 11 of a pair of electrodes protrude in opposite directions from each other. That is, in the electrode group 1, the positive electrode uncoated portion (uncoated portion 11 of the positive electrode) protrudes to one side in the longitudinal direction of the electrode group 1 relative to the negative electrode and the separator. In addition, in the electrode group 1, the negative electrode uncoated portion (uncoated portion 11 of the negative electrode) protrudes to the opposite side in the longitudinal direction of the electrode group 1 relative to the positive electrode and the separator from the side from which the positive electrode uncoated portion protrudes. Therefore, in the electrode group 1, the positive electrode uncoated portion forms a protruding portion of the positive electrode current collector, and the negative electrode uncoated portion forms a protruding portion of the negative electrode current collector.

[0014] 1 and 2, two current collecting bundle portions 12 are formed in each of a pair of uncoated portions 11, i.e., in each of the positive electrode uncoated portion and the negative electrode uncoated portion. In each of the current collecting bundle portions 12, a plurality of current collecting band portions 13 are stacked in the thickness direction of the electrode group 1, and the plurality of current collecting band portions 13 are bundled together. In each of the current collecting bundle portions 12 in the positive electrode uncoated portion, each of the plurality of bundled current collecting band portions 13 is formed from the positive electrode current collector. In each of the current collecting bundle portions 12 in the negative electrode uncoated portion, each of the plurality of bundled current collecting band portions 13 is formed from the negative electrode current collector. In each of the pair of uncoated portions 11, the two current collecting bundle portions 12 are formed spaced apart from each other in the thickness direction of the electrode group 1.

[0015] In a battery such as a secondary battery, the electrode group 1 having the above-described configuration is housed inside an exterior part. Examples of the exterior part include a metal container and a laminate film. In addition, in the battery, an electrolyte is held in the electrode group 1 housed inside the exterior part. The electrolyte may be, for example, an electrolytic solution, a gel electrolyte, or a solid electrolyte.

[0016] In addition, in a battery, a positive electrode terminal and a negative electrode terminal are formed as a pair of terminals on an exterior part or the like. Each current collecting bundle part 12 in the uncoated positive electrode part is electrically connected to the positive electrode terminal via a conductive member such as a positive electrode lead therebetween, and each current collecting bundle part 12 in the uncoated negative electrode part is electrically connected to the negative electrode terminal via a conductive member such as a negative electrode lead therebetween. Therefore, in a battery, each current collecting bundle part 12 is electrically connected to a corresponding one of the pair of terminals.

[0017] In the example shown in FIGS. 1 and 2 , a clip member (backup lead) 15 is attached to each of the current collecting bundle portions 12 in each of a pair of uncoated portions 11. Each of the clip members 15 is formed from a conductive material, and each of the current collecting bundle portions 12 is sandwiched by the clip members 15 from both sides in the thickness direction of the electrode group 1. In the battery, each of the current collecting bundle portions 12 in each of the uncoated portions 11 is joined to a corresponding one of the positive electrode lead and the negative electrode lead while being sandwiched by the clip members 15. Note that in one example, the clip members 15 are not provided, and the clip members 15 are not attached to each of the current collecting bundle portions 12. In this case, in the battery, each of the current collecting bundle portions 12 in each of the uncoated portions 11 is directly joined to a corresponding one of the positive electrode lead and the negative electrode lead.

[0018] The manufacture of the electrode group 1 will be described below. In the manufacture of the electrode group 1, first, an electrode group structure is formed. Fig. 3 is a perspective view illustrating an example of a process for forming an electrode group structure 20 in an embodiment. As shown in Fig. 3 etc., the electrode group structure 20 also has a defined length direction (direction indicated by arrow L), width direction (direction indicated by arrow W), and thickness direction (direction indicated by arrow T), similar to the electrode group 1.

[0019] 3, an electrode group structure 20 is formed from two electrode sheets, a positive electrode sheet 21A and a negative electrode sheet 21B, and two separator sheets 22. In the electrode group 1 formed from the electrode group structure 20, the positive electrode sheet 21A forms a positive electrode, and the negative electrode sheet 21B forms a negative electrode. In the electrode group 1 formed from the electrode group structure 20, the separator sheet 22 forms a separator that electrically insulates the positive electrode and the negative electrode.

[0020] In forming the electrode group structure 20, a stacked structure is formed by stacking the positive electrode sheet 21A, the negative electrode sheet 21B, and the separator sheet 22. Then, the stacked structure formed by stacking four sheets is wound to form the electrode group structure 20. The electrode group structure 20 formed by winding the stacked structure has a winding axis C as the central axis of winding. In the electrode group structure 20, the winding axis C is along the length direction. For this reason, in the electrode group structure 20, the length direction is also referred to as the "axial direction."

[0021] In the electrode group structure 20, a circumferential direction is defined as the direction around the winding axis C. In addition, in the electrode group structure 20, a radial direction that intersects both the axial direction (length direction) and the circumferential direction is defined. In the electrode group structure 20, the side approaching the winding axis C in the radial direction corresponds to the inner peripheral side, and the side away from the winding axis C in the radial direction corresponds to the outer peripheral side. An internal space 23 is formed inside the electrode group structure 20. The internal space 23 is covered from the outer peripheral side by the wound portion of the stacked structure. In the electrode group structure 20, the wound portion covers the internal space 23 over the entire circumferential direction.

[0022] In the electrode group structure 20 obtained by winding the stacked structure, a plurality of sheet portions are stacked radially in the wound portion. Therefore, the wound portion of the electrode group structure 20 has an innermost sheet portion 25 as the innermost sheet portion. The innermost sheet portion 25 is adjacent to the internal space 23 from the outer periphery side. The innermost sheet portion 25 is also formed from one of the two electrode sheets.

[0023] 3, four sheets are stacked in the stack in the order of negative electrode sheet 21B, separator sheet 22, positive electrode sheet 21A, and separator sheet 22. In the electrode group structure 20, the innermost sheet portion 25 is formed from a portion of the negative electrode sheet 21B. In one example, four sheets are stacked in the stack in the order of positive electrode sheet 21A, separator sheet 22, negative electrode sheet 21B, and separator sheet 22. In the electrode group structure 20, the innermost sheet portion 25 is formed from a portion of the positive electrode sheet 21A.

[0024] As shown in FIG. 3 and other figures, the positive electrode sheet 21A, which serves as the positive electrode, includes a current collector (positive electrode current collector) 26A and an active material-containing layer (positive electrode active material-containing layer) 27A coated on the surface of the current collector 26A. The current collector 26A of the positive electrode sheet 21A includes an uncoated portion (positive electrode uncoated portion) where the active material-containing layer 27A is not coated. The negative electrode sheet 21B, which serves as the negative electrode, includes a current collector (negative electrode current collector) 26B and an active material-containing layer (negative electrode active material-containing layer) 27B coated on the surface of the current collector 26B. The current collector 26B of the negative electrode sheet 21B includes an uncoated portion (negative electrode uncoated portion) where the active material-containing layer 27B is not coated.

[0025] Furthermore, in the electrode group structure 20, the current collectors 26A, 26B of the electrode sheets (positive electrode sheet 21A and negative electrode sheet 21B) protrude in the axial direction (lengthwise direction) along the winding axis C. That is, in the electrode group structure 20, the uncoated portion of the current collector 26A of the positive electrode sheet 21A protrudes toward one side in the lengthwise direction (axial direction) relative to the negative electrode sheet 21B and the separator sheet 22, and the uncoated portion of the current collector 26B of the negative electrode sheet 21B protrudes toward the side opposite to the side from which the current collector 26A protrudes in the lengthwise direction relative to the positive electrode sheet 21A and the separator sheet 22. Due to this configuration, in the electrode group structure 20, the current collectors 26A, 26B of the electrode sheets each have a protruding portion 28 protruding in the lengthwise direction.

[0026] In manufacturing the electrode group 1, once the electrode group structure 20 is formed as described above, a preliminary press (preliminary pressure) treatment and a preheat treatment are performed on the formed electrode group structure 20 in this order. Then, the electrode group structure 20 that has undergone the preheat treatment is transported to a molding device that forms the current collecting bundle portion 12. In the embodiment and the like, the molding device performs treatments related to forming the current collecting bundle portion 12 onto the respective protruding portions 28 of the current collectors 26A, 26B. In the embodiment and the like, a pressurizing unit such as a press machine is provided in the molding device that performs treatments related to forming the current collecting bundle portion 12. In the molding device, the pressurizing unit applies pressure to the electrode group structure 20, thereby compressing the electrode group structure 20 in the thickness direction.

[0027] 4 shows an example of the configuration of a forming device 30 that performs processing related to the formation of the current collecting bundle portion 12 on the electrode group structure 20 in an embodiment. In FIG. 4, the configuration of the forming device 30 is shown schematically in a block diagram. As shown in FIG. 4, the forming device 30 includes a control unit 31, a holding jig 32, a bundling jig 33, a pressure unit 35, jig moving units 36 and 37, and an imaging unit 38. The control unit 31 controls the overall operation of the forming device 30 and controls operations related to the formation of the current collecting bundle portion 12.

[0028] The control unit 31 includes a processor or integrated circuit (control circuit) including a CPU (Central Processing Unit), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or the like, and a storage medium such as a memory. The control unit 31 may include only one integrated circuit or the like, or may include multiple integrated circuits or the like. The control unit 31 performs processing by executing programs or the like stored in a storage medium or the like. Control by the control unit 31 may be performed by an integrated circuit or the like of a single computer, or may be performed by integrated circuits or the like of multiple computers working together. Furthermore, control by the control unit 31 may be performed by a server or the like in a cloud environment.

[0029] The pressure applying unit 35 is, for example, a press machine or the like, and applies pressure to the electrode group structure 20 by operating. When a process related to the formation of the current collecting bundle unit 12 is being performed, the control unit 31 controls the operation of the pressure applying unit 35. Furthermore, each of the jig moving units 36, 37 is a driving member such as an electric motor, and is driven, for example, by supplying electricity. In the example of FIG. 4 , the holding jig 32 is moved by driving the jig moving unit 36, and the bundling jig 33 is moved by driving the jig moving unit 37. When a process related to the formation of the current collecting bundle unit 12 is being performed, the control unit 31 controls the driving of the jig moving units 36, 37, thereby controlling the movement of each of the holding jig 32 and the bundling jig 33. As a result, the positions of each of the holding jig 32 and the bundling jig 33 are adjusted.

[0030] The photographing unit 38 is, for example, a camera, an image sensor, or the like. In the example of FIG. 4 , the photographing unit 38 photographs the electrode group structure 20 transported to the forming device 30. In the forming device 30, the photographing unit 38 photographs an image of the electrode group structure 20 including the innermost circumferential sheet portion 25 in the photographed range. The control unit 31 controls operations related to the forming of the current collecting bundle portion 12 based on the photographed image of the electrode group structure 20. For example, the control unit 31 controls the movement of the pressing jig 32 and adjusts the position of the pressing jig 32 based on the photographed image of the electrode group structure 20.

[0031] Here, in the manufacture of the electrode group 1, as described above, in the process from when the electrode group structure 20 is formed until the start of treatment by the molding device 30, that is, in the process from when the electrode group structure 20 is formed until the start of forming the current collecting bundle portion 12, the electrode group structure 20 is subjected to a preliminary press (preliminary pressure) treatment, a preheating treatment, and the like. In addition, in the manufacture of the electrode group 1, it is necessary to transport the electrode group structure 20 from an apparatus that performs the preliminary press treatment to an apparatus that performs the preheating treatment, and to transport the electrode group structure 20 from the apparatus that performs the preheating treatment to the molding device 30, and the like. Therefore, in the process from when the electrode group structure 20 is formed until the start of treatment by the molding device 30, an external force acts on the electrode group structure 20 due to the preliminary press treatment, transportation, and the like, and thermal expansion, thermal contraction, and the like occur in the electrode group structure 20 due to the thermal load of the preheating treatment.

[0032] Since the electrode group 1 is manufactured as described above, loosening occurs in the wound portion of the electrode group structure 20 during the process from when the electrode group structure 20 is formed until when the molding of the current collecting bundle part 12 begins. For this reason, in the electrode group structure 20 immediately before the start of processing by the molding device 30, that is, in the electrode group structure 20 immediately before the molding of the current collecting bundle part 12 begins, the innermost circumferential sheet part 25 is prone to slipping, and the electrode group structure 20 is prone to deformation due to the slippage of the innermost circumferential sheet part 25.

[0033] FIG. 5 schematically shows an example of the electrode group structure 20 immediately before the start of forming the current collecting bundle portion 12 in the embodiment and the like. FIG. 5 shows the electrode group structure 20 in a cross section perpendicular or substantially perpendicular to the longitudinal direction (axial direction). In the example of FIG. 5, the innermost circumferential sheet portion 25 is formed by a part of an electrode sheet 21α, which is one of the positive electrode sheet 21A and the negative electrode sheet 21B. The electrode sheet 21α defines the longitudinal direction. In the electrode group structure 20, four sheets are wound with the longitudinal direction of the electrode sheet 21α aligned along the circumferential direction of the electrode group structure 20.

[0034] The electrode sheet 21α also has an edge E1 that forms one end in the longitudinal direction. In the electrode group structure 20, the edge E1 of the electrode sheet 21α forms the inner peripheral edge of the wound portion. In the electrode group structure 20, the edge E1 (inner peripheral edge of the wound portion) of the electrode sheet 21α extends along the length direction (axial direction). In the electrode group structure 20, the innermost peripheral sheet portion 25 is formed by a one-round portion of the electrode sheet 21α that extends from the edge E1 around the entire circumference.

[0035] Here, the end of the innermost circumferential sheet portion 25 opposite to the edge E1 is defined as the edge position E2. As described above, the innermost circumferential sheet portion 25 extends around the entire circumferential direction of the electrode group structure 20. Therefore, the edge position E2 is not shifted, or is barely shifted, from the edge E1 in the circumferential direction of the electrode group structure 20. In other words, the edge position E2 is located at the same or approximately the same angular position as the edge E1 in the circumferential direction of the electrode group structure 20.

[0036] The innermost sheet portion 25 also has a pair of folding positions B1, B2. The innermost sheet portion 25 is folded at each of the folding positions B1, B2. In the innermost sheet portion 25, the folding position (first folding position) B1 is located away from the folding position (second folding position) B2 in the width direction of the electrode group structure 20. The folding position B2 faces the folding position B1 with the internal space 23 therebetween, and is located at an angle of 180° or approximately 180° away from the folding position B1 in the circumferential direction of the electrode group structure 20. In the innermost sheet portion 25, the folding position B1 is at one end position in the width direction of the electrode group structure 20, and the folding position B2 is at the end position opposite the folding position B1 in the width direction of the electrode group structure 20.

[0037] The innermost sheet portion 25 extends around one periphery in the circumferential direction of the electrode group structure 20 from the edge E1 to the edge position E2, passing through the turn-back positions B1 and B2 in this order. In the innermost sheet portion 25, the extension length from the edge E1 to the turn-back position (first turn-back position) B1 is shorter than the extension length from the edge E1 to the turn-back position (second turn-back position) B2. The difference between the extension length from the edge E1 to the turn-back position B1 and the extension length from the edge E1 to the turn-back position B2 corresponds to the extension length of the semi-circular portion 41 that extends around half the circumference between the turn-back positions B1 and B2.

[0038] 5 , in the electrode group structure 20 immediately before the formation of the current collecting bundle portion 12 begins, due to slippage of the innermost circumferential sheet portion 25, a part of the innermost circumferential sheet portion 25 floats relative to the adjacent sheet portion 42 adjacent to the outer circumferential side of the innermost circumferential sheet portion 25. As a result, a gap 43 is formed between the innermost circumferential sheet portion 25 and the adjacent sheet portion 42 at the part where the innermost circumferential sheet portion 25 floats. The adjacent sheet portion 42 is formed, for example, by a part of a separator sheet 22α, which is one of the two separator sheets 22.

[0039] 5, in the innermost sheet portion 25, a floating start position Q1 is formed in a semicircular portion 41 between folded-back positions B1 and B2, where the innermost sheet portion 25 begins to float relative to the adjacent sheet portion 42. In the innermost sheet portion 25, an extending portion from the floating start position Q1 to the edge E1, including the folded-back position B1, floats relative to the adjacent sheet portion 42. In the innermost sheet portion 25, a gap 43 is formed between the extending portion from the floating start position Q1 to the edge E1 and the adjacent sheet portion 42. In addition, in the innermost sheet portion 25, an extending portion from the floating start position Q1 to the edge E2, including the folded-back position B2, does not float relative to the adjacent sheet portion 42 and is in contact with the adjacent sheet portion 42.

[0040] Furthermore, in a configuration in which the innermost sheet portion 25 extends from the edge E1, passing through the turn-back positions B1 and B2 in this order, in the semicircular portion 41 between the turn-back positions B1 and B2, the lift start position Q1 tends to be formed closer to the turn-back position B2 than to the turn-back position B1. That is, in the semicircular portion 41 of the innermost sheet portion 25, the lift start position Q1 tends to be formed more easily in the quarter-circumference portion closer to the turn-back position B2 than in the quarter-circumference portion closer to the turn-back position B1.

[0041] FIG. 6 is a flowchart schematically illustrating an example of processing performed in the control unit 31 and the like of the forming apparatus 30 in the embodiment. FIG. 6 illustrates an example of processing from when the electrode group structure 20 that has been subjected to the preliminary pressing process and the preheating process is transported to the forming apparatus 30 to when the current collecting bundle portion 12 is formed on the transported electrode group structure 20. As shown in FIG. 6 and other figures, in the forming apparatus 30, an image of the transported electrode group structure 20 is captured by the photographing unit 38. At this time, the image is captured by the photographing unit 38 with the innermost circumferential sheet portion 25 included in the photographing range. The photographing unit 38 photographs the electrode group structure 20 from one side in the longitudinal direction of the electrode group structure 20. The control unit 31 acquires the photographed image including the innermost circumferential sheet portion 25 in the photographing range (S101).

[0042] The control unit 31 performs image analysis and image processing on the acquired photographed image to identify a lift start position Q1 of the innermost circumferential sheet portion 25 for the photographed electrode group structure 20 (S102). The control unit 31 may also perform image analysis and image processing on the photographed image to identify the edge E1 and folded-back positions B1, B2, etc. of the innermost circumferential sheet portion 25. The control unit 31 then drives the jig moving unit 36 ​​to insert the holding jig 32 into the internal space 23 (S103). At this time, the holding jig 32 is inserted into the internal space 23 from one side in the longitudinal direction of the electrode group structure 20. Furthermore, when the holding jig 32 is inserted into the internal space 23, it is inserted into the internal space 23 without coming into contact with the electrode group structure 20.

[0043] Then, the control unit 31 controls the driving of the jig moving unit 36 ​​to adjust the position of the inserted pressing jig 32 in the internal space 23, and abuts the pressing jig 32 against the innermost peripheral sheet portion 25 of the electrode group structure 20 at the adjusted position (S104). At this time, the position of the pressing jig 32 in the internal space 23 is adjusted by, for example, moving the pressing jig 32 in one or more of the length direction, width direction, and thickness direction of the electrode group structure 20. Furthermore, the control unit 31 adjusts the position of the pressing jig 32 based on, for example, the images captured by the imaging unit 38 and the results of image analysis of the captured images.

[0044] The holding jig 32 inserted into the internal space 23 abuts against the electrode group structure 20 from the inner circumferential side, and thereby the innermost circumferential sheet portion 25 is held down from the inner circumferential side by the holding jig 32. Based on the captured image, etc., the control unit 31 adjusts the position of the holding jig 32 in the internal space 23, for example, so that the folding position (first folding position) B1 and the lift start position Q1 are both held down by the holding jig 32. That is, based on the captured image, the analysis results of the image analysis of the captured image, etc., the control unit 31 controls the driving of the jig moving unit 36 ​​to adjust the position at which the holding jig 32 abuts on the innermost circumferential sheet portion 25 of the electrode group structure 20.

[0045] With the innermost peripheral sheet portion 25 being held down from the inner peripheral side by the holding jig 32, the control unit 31 drives the jig moving unit 37 to insert the binding jig 33 into the internal space 23 of the electrode group structure 20 (S105). At this time, the binding jig 33 is inserted into the internal space 23 from the length direction of the electrode group structure 20. Then, after the binding jig 33 has been inserted into the internal space 23, the control unit 31 drives the jig moving unit 36 ​​to remove the holding jig 32 from the internal space 23 (S106). At this time, the binding jig 33 is not removed from the internal space 23, but remains inserted in the internal space 23.

[0046] Then, in response to the removal of the pressing jig 32 from the internal space 23, the control unit 31 operates the pressing unit 35 to apply pressure to the electrode group structure 20 from the pressing unit 35 (S107). The application of pressure from the pressing unit 35 compresses the electrode group structure 20 in the thickness direction. Then, in parallel with the application of pressure to the electrode group structure 20 by the pressing unit 35, the control unit 31 drives the jig moving unit 37 to press the protruding portions 28 of the current collectors 26A, 26B from the internal space 23 with the bundling jig 33 (S108). As a result, the multiple current collecting band portions 13 are bundled in the protruding portions 28 of each of the current collectors 26A, 26B, and a current collecting bundle portion 12 is formed. Therefore, the bundling jig 33 is used to form the current collecting bundle portion 12 in the protruding portions 28 of each of the current collectors 26A, 26B.

[0047] 7 schematically shows an example of changes in the state of the electrode group structure 20 and its vicinity from when the electrode group structure 20 is conveyed to the molding apparatus 30 until immediately before the pressure unit 35 starts applying pressure to the electrode group structure 20 in the embodiment. In the example of FIG. 7, the states change in the order of states α1, α2, α3, α4, and α5. In addition, in the example of FIG. 7, two pressing jigs 32A and 32B are provided as the pressing jig 32, and a pair of bundling jigs 33A and 33B are used as the bundling jig 33. In the example of FIG. 7, the electrode group structure 20 is shown as viewed from one side in the thickness direction.

[0048] 7 , in state α1, the electrode group structure 20 transported to the forming apparatus 30 is photographed by the photographing unit 38 with the innermost sheet portion 25 included in the photographing range. Then, in state α1, the photographed image is subjected to image analysis or the like to identify the lift start position Q1, the edge E1, and the folded-back positions B1 and B2 of the innermost sheet portion 25. In state α1, the pressing jigs 32A and 32B and the bundling jigs 33A and 33B are placed in standby positions and are not inserted into the internal space 23 of the electrode group structure 20. In the example of FIG. 7 , in state α1 where the pressing jigs 32A and 32B and the bundling jig 33B are placed in standby positions, the pressing jigs 32A and 32B and the bundling jig 33B are placed away from the electrode group structure 20 on the side from which the negative electrode current collector 26B protrudes in the longitudinal direction, and the bundling jig 33A is placed away from the electrode group structure 20 on the side from which the positive electrode current collector 26A protrudes in the longitudinal direction.

[0049] Then, when image analysis of the captured images and the like are completed, in state α2, the pressing jigs 32A and 32B are moved from their standby positions and inserted into the internal space 23 of the electrode group structure 20 (arrow A1). At this time, the pressing jigs 32A and 32B are inserted into the internal space 23 in a state where they are not in contact with the wound portion of the electrode group structure 20. In the example of FIG. 7 , the pressing jigs 32A and 32B are inserted into the internal space 23 of the electrode group structure 20 from the side in the longitudinal direction from which the negative electrode current collector 26B protrudes. Also in state α2, the binding jigs 33A and 33B are arranged at the standby position without moving from the standby position.

[0050] Then, when the pressing jigs 32A and 32B are inserted into the internal space 23, in state α3, the positions of the pressing jigs 32A and 32B are adjusted. The adjustment of the positions of the pressing jigs 32A and 32B is performed by one or more of moving the pressing jigs 32A and 32B in the width direction of the electrode group structure 20 (arrow A2), moving the pressing jigs in the length direction of the electrode group structure 20 (arrow A3), and moving the pressing jigs 32A and 32B in the thickness direction of the electrode group structure 20. Then, in state α3, the pressing jigs 32A and 32B are brought into contact with the innermost peripheral sheet portion 25 of the electrode group structure 20 at the adjusted positions. As a result, the innermost peripheral sheet portion 25 is pressed down from the inner periphery by the pressing jigs 32A and 32B, respectively.

[0051] In the internal space 23, each of the pressing jigs 32A and 32B is movable in the longitudinal direction of the electrode group structure 20 in a range from the protruding portion 28 of the positive electrode current collector 26A to the protruding portion 28 of the negative electrode current collector 26B. That is, in the internal space 23, each of the pressing jigs 32A and 32B is movable to a region on the inner circumferential side of the protruding portion 28 of the positive electrode current collector 26A and is also movable to a region on the inner circumferential side of the protruding portion 28 of the negative electrode current collector 26B. Furthermore, in the internal space 23, each of the pressing jigs 32A and 32B is capable of contacting the innermost circumferential sheet portion 25 over the entire length (total length) or almost the entire length between the base position of the protruding portion 28 of the positive electrode current collector 26A and the base position of the protruding portion 28 of the negative electrode current collector 26B in the longitudinal direction of the electrode group structure 20.

[0052] Then, in state α4, with the innermost sheet portion 25 held down by the holding jigs 32A and 32B, the binding jigs 33A and 33B are inserted into the internal space 23 of the electrode group structure 20 (arrow A4). In the example of FIG. 7 , the binding jig 33A is inserted into the internal space 23 from the side in the longitudinal direction from which the protruding portion 28 of the positive electrode current collector 26A protrudes, and is inserted up to a region on the inner periphery of the protruding portion 28 of the positive electrode current collector 26A. Then, the binding jig 33B is inserted into the internal space 23 from the side in the longitudinal direction from which the protruding portion 28 of the negative electrode current collector 26B protrudes, and is inserted up to a region on the inner periphery of the protruding portion 28 of the negative electrode current collector 26B.

[0053] In one example, only one bundling jig 33 is used instead of the pair of bundling jigs 33A and 33B. In this example, as in state α4, the innermost peripheral sheet portion 25 is held down by the holding jigs 32A and 32B, and then the single bundling jig 33 is inserted into the internal space 23 of the electrode group structure 20. In this example, the bundling jig 33 is inserted into the internal space 23 from the side from which the protruding portion 28 of the positive electrode current collector 26A in the longitudinal direction protrudes, or from the side from which the protruding portion 28 of the negative electrode current collector 26B in the longitudinal direction protrudes.

[0054] 8 is a schematic cross-sectional view of the exemplary state α4 of FIG. 7 , which is perpendicular or substantially perpendicular to the longitudinal direction of the electrode group structure 20. As shown in FIG. 8 and other figures, the bundling jigs 33A and 33B are inserted into the internal space 23 without contacting the pressing jigs 32A and 32B inserted in the internal space 23. Therefore, in the state α4 in which the pressing jigs 32A and 32B and the bundling jigs 33A and 33B are inserted into the internal space 23, the bundling jigs 33A and 33B do not contact the pressing jigs 32A and 32B. Furthermore, in the state α4, the bundling jigs 33A and 33B inserted into the internal space 23 do not contact the wound portion of the electrode group structure 20.

[0055] 7 and 8, the holding jig 32A holds down the innermost sheet portion 25 at the turn-back position (first turn-back position) B1 and its vicinity. The holding jig 32B holds down the innermost sheet portion 25 at the lift-up start position Q1 and its vicinity. Therefore, in the half-circumference portion 41 extending over half the circumference between the turn-back positions B1 and B2, the portion corresponding to the lift-up start position Q1 is held down by the holding jig 32B. In the example shown in FIGS. 7 and 8, the lift-up start position Q1 is formed in the quarter-circumference portion closer to the turn-back position B2 in the half-circumference portion 41, and the portion corresponding to the lift-up start position Q1 in the quarter-circumference portion closer to the turn-back position B2 is held down by the holding jig 32B. In a preferred example, the holding jig 32A holds down the turn-back position B1 and its vicinity, and then, with the turn-back position B1 held down, the holding jig 32B holds down the lift-up start position Q1 and its vicinity.

[0056] In one example, the photographing unit 38 is not provided, and no photographed image of the electrode group structure 20 is taken. In this case, design information of the electrode group structure 20 is stored in a storage medium or the like of the control unit 31. Then, the control unit 31 specifies a folding position (first folding position) B1 of the innermost circumferential sheet portion 25 based on the design information. Then, the control unit 31 adjusts the position of the pressing jig 32A in the internal space 23 so that the pressing jig 32A holds down the innermost circumferential sheet portion 25 at and near the folding position B1.

[0057] Furthermore, in this example, the control unit 31 estimates a portion of the innermost sheet portion 25 that is likely to float relative to the adjacent sheet portion 42 based on design information and the like, and estimates a position that is likely to be the float start position Q1. Then, the control unit 31 adjusts the position of the holding jig 32B in the internal space 23 so that the holding jig 32B holds the innermost sheet portion 25 at the position estimated to be the float start position Q1. Therefore, in the semi-circumferential portion 41 that extends over half the circumference between the folding positions B1 and B2, the portion that corresponds to the position estimated to be the float start position Q1 is held down by the holding jig 32B.

[0058] Furthermore, as described above, in the semicircular portion 41 of the innermost sheet portion 25, the lift start position Q1 tends to be formed in the quarter-circular portion closer to the turn-back position B2. For this reason, in one example, the control unit 31 estimates, based on design information or the like, a position in the semicircular portion 41 closer to the turn-back position B2 that is likely to be the lift start position Q1. The control unit 31 adjusts the position of the holding jig 32B in the internal space 23 so that the holding jig 32B holds the innermost sheet portion 25 at the position estimated to be the lift start position Q1. As a result, the portion of the semicircular portion 41 closer to the turn-back position B2 that corresponds to the position estimated to be the lift start position Q1 is held down by the holding jig 32B.

[0059] 7 , in state α4, the bundling jigs 33A and 33B are inserted into the internal space 23, and then in state α5, the pressing jigs 32A and 32B are each removed from the internal space 23 of the electrode group structure 20 (arrow A5). Note that in state α5, the bundling jigs 33A and 33B are not removed from the internal space 23, but are maintained inserted in the internal space 23. Then, in the molding device 30, in response to the removal of the pressing jigs 32A and 32B from the internal space 23 in state α5, pressure is applied to the electrode group structure 20 by the pressurizing unit 35.

[0060] 9 schematically shows an example of a state immediately after the application of pressure to the electrode group structure 20 by the pressure unit 35 begins after state α5 in FIG. 7 in an embodiment. In FIG. 9, the electrode group structure 20 is shown in a cross section perpendicular or substantially perpendicular to the width direction. In the example in FIG. 9, the pressure unit 35 includes a pair of press plates 51, 52, and the press plate (movable press plate) 52 is movable relative to the press plate (fixed press plate) 51.

[0061] In the pressure unit 35, pressure is applied to the electrode group structure 20 by sandwiching the electrode group structure 20 between press plates 51 and 52. At this time, the press plate 51 is brought into contact with the electrode group structure 20 from one side in the thickness direction, and the press plate 52 is brought into contact with the electrode group structure 20 from the side opposite the press plate 51 in the thickness direction. Then, the press plate 52 presses the electrode group structure 20, thereby applying pressure to the electrode group structure 20 from one side (outside) in the thickness direction (arrow F1). As a result, the electrode group structure 20 is compressed in the thickness direction.

[0062] In addition, when the electrode group structure 20 is sandwiched between the press plates 51, 52, each of the press plates 51, 52 abuts against the electrode group structure 20 between the base position of the protruding portion 28 of the positive electrode current collector 26A and the base position of the protruding portion 28 of the negative electrode current collector 26B in the longitudinal direction of the electrode group structure 20. Therefore, the press plates 51, 52 do not come into contact with the protruding portion 28 of the positive electrode current collector 26A or the protruding portion 28 of the negative electrode current collector 26B.

[0063] Furthermore, when the application of pressure by the pressure unit 35 begins, the control unit 31 controls the operation of the pressure unit 35 to compress the electrode group structure 20 until the dimension (thickness) X of the electrode group structure 20 along the thickness direction becomes the specified thickness Xref. FIG. 9 shows a state in which the electrode group structure 20 is compressed to the specified thickness Xref. Furthermore, while the electrode group structure 20 is compressed to the specified thickness Xref, the control unit 31 adjusts the positions of the binding jigs 33A and 33B in the internal space 23, for example, to prevent the binding jigs 33A and 33B from contacting the wound portion of the electrode group structure 20. Therefore, while the electrode group structure 20 is being compressed to the specified thickness Xref, the binding jigs 33A and 33B do not come into contact with the protruding portions 28 of the positive electrode current collector 26A and the negative electrode current collector 26B.

[0064] In the molding device 30, the electrode group structure is compressed to a specified thickness Xref by applying pressure using the pressure unit 35, and then a current collecting bundle portion 12 is formed on the protruding portion 28 of the positive current collector 26A using a bundling jig 33A, and a current collecting bundle portion 12 is formed on the protruding portion 28 of the negative current collector 26B using a bundling jig 33B. Even during the process of forming the current collecting bundle portion 12, the electrode group structure 20 is sandwiched between press plates 51 and 52, and pressure is applied to the electrode group structure 20 from the pressure unit 35. Therefore, in parallel with the application of pressure to the electrode group structure 20 by the pressure unit 35, the bundling jigs 33A and 33B are used to bundle the multiple current collecting band portions 13.

[0065] FIG. 10 schematically illustrates an example of a state in which the current collecting bundle portion 12 is formed using bundling jigs 33A and 33B after the state illustrated in FIG. 9 in an embodiment. In FIG. 10, the electrode group structure 20 is shown in a cross section perpendicular or substantially perpendicular to the width direction. As illustrated in FIG. 10 and other figures, in the molding device 30, the electrode group structure 20 is sandwiched between the press plates 51 and 52 even after the electrode group structure 20 has been compressed to the specified thickness Xref. The press plates 52 then press the electrode group structure 20, thereby applying pressure to the electrode group structure 20 from one side (outside) in the thickness direction (arrow F2). After the electrode group structure 20 has been compressed to the specified thickness Xref, the control unit 31 controls the operation of the press unit 35 to adjust the magnitude of the pressure applied to the electrode group structure 20 from the press unit 35 to the specified pressure Pref.

[0066] 10 , in parallel with the application of pressure to the electrode group structure 20 at the specified pressure Pref, the control unit 31 moves each of the binding jigs 33A and 33B inserted into the internal space 23 along the thickness direction (arrow A6). At this time, each of the binding jigs 33A and 33B moves along the thickness direction between the position indicated by the solid line and the position indicated by the dashed line in FIG. 10 . As a result of the binding jig 33A moving as described above in the region on the inner periphery of the protruding portion 28 of the positive current collector 26A, the protruding portion 28 of the positive current collector 26A is pressed by the binding jig 33A from the inside in the thickness direction, i.e., from the internal space 23. As a result, in the protruding portion 28 of the positive current collector 26A, the multiple current collecting band portions 13 are bundled by the binding jig 33A by the binding jig 33A, and a current collecting bundle portion 12 is formed.

[0067] Furthermore, in the region on the inner periphery of the protruding portion 28 of the negative electrode current collector 26B, the binding jig 33B moves as described above, and thus the protruding portion 28 of the negative electrode current collector 26B is pressed by the binding jig 33B from the inside in the thickness direction, i.e., from the internal space 23. As a result, in the protruding portion 28 of the negative electrode current collector 26B, the binding jig 33B bundles together the multiple current collecting band portions 13, forming a current collecting bundle portion 12. In the example of FIG. 10 , in each of the protruding portions 28 of the positive electrode current collector 26A and the negative electrode current collector 26B, the current collecting bundle portions 12 are formed at a portion adjacent to the side where the press plate 51 is located with respect to the internal space 23 and at a portion adjacent to the side where the press plate 52 is located with respect to the internal space 23.

[0068] 9 and 10 , in the application of pressure from the pressure applying unit 35 to the electrode group structure 20, after the electrode group structure 20 has been compressed to the specified thickness Xref, the magnitude of the pressure applied to the electrode group structure 20 is set to the specified pressure Pref. However, in one example, pressure may be applied to the electrode group structure 20 at the specified pressure Pref from the start of application of pressure to the electrode group structure 20.

[0069] In another example, instead of the pair of binding tools 33A and 33B, only one binding tool 33 is used. Then, in parallel with the application of pressure to the electrode group structure 20 at the specified pressure Pref, one of the protruding portions 28 of the positive electrode current collector 26A and the negative electrode current collector 26B is pressed from the internal space 23 by the binding tool 33. As a result, in one of the protruding portions 28 of the positive electrode current collector 26A and the negative electrode current collector 26B, the binding tool 33 bundles multiple current collecting band portions 13 together to form a current collecting bundle portion 12. In this example, after the current collecting bundle portion 12 is formed in one of the protruding portions 28 of the positive electrode current collector 26A and the negative electrode current collector 26B, the binding tool 33 is removed from the internal space 23. Then, the binding jig 33 is inserted again into the internal space 23 from the side where the other protruding portions 28 of the positive electrode current collector 26A and the negative electrode current collector 26B protrude. Then, in parallel with the application of pressure to the electrode group structure 20 at the specified pressure Pref, the other protruding portions 28 of the positive electrode current collector 26A and the negative electrode current collector 26B are pressed from the internal space 23 by the binding jig 33. As a result, the multiple current collecting band portions 13 are also bundled by the binding jig 33 at the other protruding portions 28 of the positive electrode current collector 26A and the negative electrode current collector 26B, forming a current collecting bundle portion 12.

[0070] In the embodiments and the like, the electrode group 1 is formed by forming the current collecting bundle parts 12 on the electrode group structure 20 as described above. In addition, in manufacturing a battery including the electrode group 1, for example, a clip member 15 is attached to each of the current collecting bundle parts 12 formed as described above. In manufacturing the battery, each of the current collecting bundle parts 12 formed on the protruding portion 28 of the positive electrode current collector 26A is joined to, for example, a positive electrode lead, and electrically connected to a positive electrode terminal via the positive electrode lead. In manufacturing the battery, each of the current collecting bundle parts 12 formed on the protruding portion 28 of the negative electrode current collector 26B is joined to, for example, a negative electrode lead, and electrically connected to a negative electrode terminal via the negative electrode lead.

[0071] As described above, in the embodiments and the like, the electrode group structure 20 is conveyed to the molding device 30, and in the internal space 23 thereof, the pressing jig 32 is brought into contact with the electrode group structure 20 from the inner periphery, thereby pressing the innermost sheet portion 25 of the electrode group structure 20 from the inner periphery by the pressing jig 32. Then, with the innermost sheet portion 25 pressed by the pressing jig 32, the bundling jig 33 used to form the current collecting bundle portion 12 is inserted into the internal space 23 of the electrode group structure 20. By pressing the innermost sheet portion 25 by the pressing jig 32, deformation of the electrode group structure 20 due to slippage of the innermost sheet portion 25, etc., is appropriately suppressed, even in a state in which the electrode group structure 20 is prone to deformation immediately before the start of molding of the current collecting bundle portion 12.

[0072] For example, in the electrode group structure 20 immediately before the start of forming the current collecting bundle section 12, a phenomenon in which the inner electrodes deform inward (sometimes referred to as "center drop") due to slippage of the innermost sheet portion 25 or the like is likely to occur as a deformation of the electrode group structure 20. When the above-mentioned "center drop" occurs, parts of the innermost sheet portion 25 that are separated in the thickness direction across the internal space 23 come into contact with each other, blocking part of the internal space 23. In the embodiment and the like, the innermost sheet portion 25 is held down by the holding jig 32, thereby appropriately suppressing the occurrence of "center drop" and the like in the electrode group structure 20 immediately before the start of forming the current collecting bundle section 12. Furthermore, in the embodiment and the like, the binding jig 33 is inserted into the internal space 23 while the deformation of the electrode group structure 20 is suppressed by the holding jig 32, so that the binding jig 33 can be appropriately inserted into the internal space 23.

[0073] By properly inserting the binding jig 33 into the internal space 23, the application of pressure by the pressure unit 35 and the pressing of the protruding portions 28 of the current collectors (26A, 26B) from the internal space 23 by the binding jig 33 as described above reduces the occurrence of defects in the molding of the current collecting bundle part 12. Reducing the occurrence of defects in the molding of the current collecting bundle part 12 improves the yield in the manufacture of the electrode group 1. Furthermore, by properly molding the current collecting bundle part 12, in the manufacture of a battery including the electrode group 1, the occurrence of defects in the process of attaching the clip members 15 to the current collecting bundle part 12 and in the process of joining the current collecting bundle part 12 to the leads by ultrasonic bonding or the like is reduced. This also improves the yield in the manufacture of the battery.

[0074] In one example of the embodiments, an image of the electrode group structure 20 including the innermost sheet portion 25 in its imaging range is captured by the imaging unit 38. The control unit 31 then controls the driving of the jig moving unit 36 ​​based on the captured image, thereby adjusting the position at which the holding jig 32 abuts on the electrode group structure 20 in the internal space 23. With this configuration, it is possible to appropriately identify, based on the captured image, the lift-off start position Q1 at which the innermost sheet portion 25 begins to lift off relative to the adjacent sheet portion 42. This makes it possible to adjust the position of the holding jig 32 in the internal space 23 so that the holding jig 32 holds the innermost sheet portion 25 at the lift-off start position Q1, and the holding jig 32 holds the innermost sheet portion 25 at an appropriate position. Therefore, deformation of the electrode group structure 20 due to slippage of the innermost sheet portion 25, etc., immediately before the start of forming the current collecting bundle portion 12, is further appropriately suppressed.

[0075] In one example of the embodiments, two holding jigs 32A and 32B are used, with the holding jig 32A holding the innermost circumferential sheet portion 25 at and near the folded-back position (first folded-back position) B1. The holding jig 32B holds the innermost circumferential sheet portion 25 at and near the lift-up start position Q1. This further appropriately suppresses deformation of the electrode group structure 20 due to slippage of the innermost circumferential sheet portion 25, etc., immediately before starting to form the current collecting bundle portion 12.

[0076] In a preferred example, the holding jig 32A holds down the folding position B1 and its vicinity, and then, with the folding position B1 held down, the holding jig 32B holds down the lift start position Q1 and its vicinity. This further appropriately suppresses deformation of the electrode group structure 20 due to slippage of the innermost circumferential sheet portion 25, etc., immediately before the start of forming the current collecting bundle part 12.

[0077] According to at least one of these embodiments or examples, the pressing jig abuts against the electrode group structure from the inner periphery side in the internal space of the electrode group structure, thereby pressing down the innermost sheet portion of the electrode group structure from the inner periphery side. Then, the bundling jig is inserted into the internal space of the electrode group structure with the innermost sheet portion being pressed down by the pressing jig. An object of the present invention is to provide a molding device and a molding method for a current collecting bundle portion that appropriately suppresses deformation of the electrode group structure and enables the bundling jig to be appropriately inserted into the internal space of the electrode group structure.

[0078] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0079] 1...electrode group, 12...current collecting bundle portion, 13...current collecting band portion, 20...electrode group structure, 21A...positive electrode sheet, 21B...negative electrode sheet, 23...internal space, 25...innermost sheet portion, 26A...positive electrode current collector, 26B...negative electrode current collector, 28...protruding portion, 30...molding device, 31...control portion, 32...holding jig, 33...binding jig, 35...pressure portion, 36, 37...jig moving portion, 38...photographing portion.

Claims

1. A forming device for forming a current collecting bundle portion in which a plurality of current collecting band portions are bundled together on a protruding portion of a current collector in an electrode group structure having a protruding current collector, the device comprising: a pressing jig that presses an innermost peripheral sheet portion of the electrode group structure from the inner peripheral side by contacting the electrode group structure from the inner peripheral side in the internal space of the electrode group structure; a bundling jig that is used to form the current collecting bundle portion and is inserted into the internal space of the electrode group structure while the innermost sheet portion is being held down by the holding jig; A molding device comprising:

2. a pressure applying unit that applies pressure to the electrode group structure in response to the pressing jig being removed from the internal space, thereby compressing the electrode group structure in a thickness direction, the bundling jig presses the protruding portion of the current collector from the internal space in parallel with the application of the pressure to the electrode group structure by the pressure unit, thereby bundling the plurality of current collecting band portions. The molding apparatus of claim 1.

3. a jig moving unit that is driven to move the holding jig; an imaging unit that captures an image including the innermost sheet portion in the electrode group structure in an imaging range; a control unit that adjusts the position at which the holding jig abuts on the electrode group structure in the internal space by controlling the drive of the jig moving unit based on the captured image of the imaging unit; The molding apparatus of claim 1 or 2, further comprising:

4. 1. A method for forming a current collecting bundle portion in an electrode group structure having a protruding current collector, in which a plurality of current collecting band portions are bundled together at a protruding portion of the current collector, comprising: a pressing jig is brought into contact with the electrode group structure from an inner circumferential side in the internal space of the electrode group structure, thereby pressing an innermost sheet portion of the electrode group structure from the inner circumferential side with the pressing jig; inserting a bundling jig used to form the current collecting bundle portion into the internal space of the electrode group structure while the innermost sheet portion is being held down by the holding jig; A molding method comprising:

5. After inserting the binding jig into the internal space, removing the holding jig from the internal space; compressing the electrode group structure in a thickness direction by applying pressure to the electrode group structure in response to removing the holding jig from the internal space; bundling the plurality of current collecting band portions by pressing the protruding portion of the current collector from the internal space with the bundling jig in parallel with the application of the pressure to the electrode group structure; The molding method of claim 4 further comprising:

Images