JP2015118866A - Manufacturing apparatus of electrode assembly and manufacturing method of electrode assembly - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing apparatus of electrode assembly and a manufacturing method of electrode assembly which allows for suppression of spring back when releasing application of a load.SOLUTION: A manufacturing apparatus 50 of an electrode assembly has a pair of holding members 51, 61 for holding an electrode assembly 14 from both flat surfaces 44 in the lamination direction, and female screw 55 and bolt 57 capable of holding the pair of holding members 51, 61 in a state for holding the electrode assembly 14, and fixing the interval of the pair of holding members 51, 61. Furthermore, the manufacturing apparatus 50 includes a first recess 68, a second recess 69 and third recesses 60, 70 in each holding member 51, 61, and they expose a part of the flat surface 44 so as to stick a first holding tape and a second holding tape to both flat surfaces of the electrode assembly 14.

Description

  The present invention relates to an electrode assembly manufacturing apparatus and an electrode assembly manufacturing method for adjusting the thickness of an electrode assembly in a stacking direction and holding the electrode assembly with a holding tape.

  A vehicle such as an EV (Electric Vehicle) or a PHV (Plug in Hybrid Vehicle) is equipped with a secondary battery such as a lithium ion battery as a power storage device that stores power supplied to an electric motor serving as a prime mover. A secondary battery includes, for example, an electrode assembly in which a rectangular positive electrode and a negative electrode each having an active material layer formed on both surfaces are stacked with a separator interposed therebetween. Among secondary batteries, when manufacturing a square secondary battery, a positive electrode, a separator, and a negative electrode are stacked to form an electrode assembly, and then the electrode assembly is in a state in which a load is applied in the stacking direction. (See, for example, Patent Document 1).

  In the multilayer nonaqueous electrolyte battery disclosed in Patent Document 1, the multilayer electrode body (electrode assembly) includes a plurality of positive electrodes (positive electrodes) and negative electrodes (negative electrodes) stacked with a separator interposed therebetween, and an adhesive tape. It is held in the stacking direction by (holding tape). In the production of the laminated electrode body, the positive electrode, the separator, and the negative electrode are conveyed to a predetermined position by an adsorption device, and the laminated positive electrode, separator, and negative electrode are pressed by the adsorption device to apply a load, thereby adjusting the thickness. And an adhesive tape is affixed on a part of laminated electrode body exposed from the adsorption | suction apparatus with the load applied. In addition, as for an adhesive tape, the both ends side of the longitudinal direction is affixed on the both ends surface of the lamination direction of a laminated electrode body. After adhering the adhesive tape, the laminated electrode body is manufactured by releasing the load applied by the adsorption device. In the laminated electrode body, displacement of the positive electrode and the negative electrode in the direction along the surface of the active material layer and displacement in the lamination direction are suppressed by the adhesive tape, and the laminated state is maintained.

JP 2008-204706 A

  However, in the manufacturing method disclosed in Patent Document 1, when the application of the load by the adsorbing device is released after the adhesive tape is applied, the positive electrode, the negative electrode, and the separator are spring-backed. The thickness of the body in the stacking direction tends to increase. Then, the adhesive tape is pulled in the longitudinal direction, and a strong force is applied to the adhesive tape. As a result, the adhesive tape is peeled off from the active material layer or the laminated state is shifted. In order to prevent the above-described inconvenience from occurring even when this spring back occurs, it is conceivable to use an adhesive tape having a high adhesive strength. However, there is a possibility that the tension applied to the adhesive tape becomes too strong, the active material layer is pulled by the adhesive tape, and the active material is peeled off from the surface of the active material layer.

  An object of the present invention is to provide an electrode assembly manufacturing apparatus and an electrode assembly manufacturing method capable of suppressing springback when load application is released.

  An apparatus for manufacturing an electrode assembly for solving the above problem is an apparatus for manufacturing an electrode assembly in which a positive electrode having an active material layer and a negative electrode are stacked with a separator interposed therebetween, A pair of clamping members that sandwich the electrode assembly from both flat surfaces in the stacking direction, and a pair of holding members that can hold the electrode assembly in a state of sandwiching the electrode assembly, and hold the gap between the pair of clamping members fixed The gist of the present invention is to include a member and a recess provided in each of the clamping members and exposing a part of both the flat surfaces of the electrode assembly.

  According to this, it is possible to stick the holding tape to the electrode assembly in a state where the electrode assembly is sandwiched between the sandwiching members by the recesses of the sandwiching member. Further, the interval between the holding members can be fixed by the holding member. For this reason, after applying the holding tape to the electrode assembly and then releasing the applied load to the electrode assembly, the holding member receives a strong force to spring back the electrode assembly and suppresses the spring back. . As a result, it is possible to suppress a strong force from the springback from being applied to the holding tape.

  In addition, the electrode assembly manufacturing apparatus includes a pressing member that includes a pressing member capable of moving forward and backward with respect to the clamping member, and the pressing member applies a load in the stacking direction to the electrode assembly via the clamping member. It is preferable to provide.

  According to this, it is possible to apply a load to the electrode assembly from the pressing member of the load applying device in a state where the electrode assembly is sandwiched between the pair of clamping members. In addition, after the interval between the pair of sandwiching members is fixed by the holding member, the electrode assembly and the sandwiching member can be separated from the load applying device by retracting the pressing member, and each can be placed separately. it can. Since the electrode assembly is clamped by the clamping member, the springback is reduced with time. Therefore, the electrode assembly and the clamping member and the load applying device can be separately placed, so that the spring back of the electrode assembly can be reduced, and the load applying device can suppress the spring back. You can avoid being occupied.

  Further, in the electrode assembly manufacturing apparatus, each of the clamping members includes a plurality of projecting portions that project along the decentered plane and away from the side surfaces connected to the decentered plane in a state of sandwiching the electrode assembly. The holding member includes a female screw portion provided at a protruding portion of one clamping member, and a bolt inserted into the protruding portion of the other clamping member and screwed into the female screw portion.

According to this, the space | interval between a pair of clamping members is fixable in the state to which the load was provided by screwing a volt | bolt in an internal thread part.
In the electrode assembly manufacturing apparatus, it is preferable that the clamping members are made of metal and the bolts are made of resin.

  According to this, when the bolt is screwed into the female thread portion of the clamping member, even if the bolt is rubbed against the female thread portion, foreign matter is hardly generated, and foreign matter is mixed into the electrode assembly manufactured by the electrode assembly manufacturing apparatus. This can be suppressed.

  A method of manufacturing an electrode assembly for solving the above problem is a method of manufacturing an electrode assembly in which a positive electrode and a negative electrode are stacked with a separator interposed therebetween, the positive electrode and the negative electrode A step of laminating a negative electrode with the separator interposed therebetween, a step of sandwiching the electrode assembly from both flat surfaces in the laminating direction by a pair of sandwiching members, and the electrode sandwiched by a pair of sandwiching members A step of applying a load to the assembly in the stacking direction, a step of fixing the interval between the pair of clamping members with a holding member, and a step of releasing the application of the load while maintaining the interval between the pair of clamping members; A step of adhering a holding tape to both of the flat surfaces across the side surfaces connected to the both flat surfaces of the electrode assembly from the recesses of the pair of holding members while maintaining the distance between the pair of holding members; After a lapse of time, a pair of clamps And summarized in that comprises a step of releasing the fixing of the spacing between the wood, the.

  According to this, since the gap between the pair of clamping members is fixed for a predetermined time by the clamping member and the holding member, the thickness of the electrode assembly in the stacking direction is maintained for a predetermined time, and the springback is reduced with the passage of time. To go. For this reason, the spring back of the electrode assembly when the clamping by the clamping member is released is reduced, and it is possible to suppress a strong force from being applied to the holding tape. In addition, even after releasing the load, the interval between the pair of holding members is fixed for a predetermined time by the holding member and the holding member, so even if the load is released, the load is applied while reducing the springback. Therefore, a decrease in production efficiency of the power storage device can be suppressed.

  According to the present invention, it is possible to suppress the springback when releasing the load.

The disassembled perspective view which shows the secondary battery of embodiment. The perspective view which shows the external appearance of the secondary battery of embodiment. The disassembled perspective view which shows the component of an electrode assembly. The disassembled perspective view which shows the clamping member and bolt of the manufacturing apparatus of an electrode assembly. The perspective view which shows the state which clamped the electrode assembly with a pair of clamping member. The side view which shows the state which provided the load with the load provision apparatus. The side view which shows the state which tightened the volt | bolt. The top view which shows the state which affixed the holding tape on the electrode assembly. The perspective view which shows the state which affixed the holding tape on the electrode assembly. The top view which shows another example of the manufacturing apparatus of an electrode assembly.

Hereinafter, an embodiment in which an electrode assembly manufacturing apparatus and an electrode assembly manufacturing method are embodied will be described with reference to FIGS.
As shown in FIG. 1 and FIG. 2, the secondary battery 10 is a lithium ion secondary battery, and includes a metal case 11 that forms the outline of the secondary battery 10. The case 11 includes a bottomed rectangular parallelepiped container 12 having an opening 12a on one surface and a lid 13 that closes the opening 12a. The container 12 has a rectangular bottom plate 12b, a short side wall 12c erected from a pair of opposed short side edges of the bottom plate 12b, and a long side wall 12d erected from a pair of opposed long side edges of the bottom plate 12b. Is provided. The case 11 contains an electrode assembly 14 and an electrolytic solution (not shown) as an electrolyte. The electrode assembly 14 has a rectangular parallelepiped shape as a whole, corresponding to the internal space of the container 12 having a rectangular parallelepiped shape.

  As shown in FIG. 3, the electrode assembly 14 is made of a rectangular sheet-like positive electrode 21 and a rectangular sheet-like negative electrode 24, and is made of resin and is porous so that ions related to electrical conduction (lithium ions) can pass therethrough. And a separator 27 formed of a material film. The positive electrode 21 has a rectangular positive electrode metal foil (aluminum foil in the present embodiment) 22 and a rectangular positive electrode active material layer 23 provided on both surfaces (surfaces) of the positive electrode metal foil 22. . Around the positive electrode active material layer 23, a positive electrode uncoated portion 22 d having no active material is formed on the surface of the positive electrode metal foil 22. A positive electrode current collecting tab 31 is provided on a part of the first side (upper side) 22 c of the positive electrode 21 so as to project a part of the positive electrode metal foil 22. In the positive electrode 21, the opposite side of the first side 22c provided with the positive current collecting tab 31 is the second side 22e, and the pair of sides connecting the first side 22c and the second side 22e is the third side. 22f.

  The negative electrode 24 has a rectangular negative electrode metal foil (copper foil in this embodiment) 25 and a rectangular negative electrode active material layer 26 provided on both surfaces (surfaces) of the negative electrode metal foil 25. . Around the negative electrode active material layer 26, a negative electrode uncoated portion 25d having no active material is formed on the surface of the negative electrode metal foil 25. A negative electrode current collecting tab 32 is provided on a part of the first side (upper side) 25 c of the negative electrode 24 so as to project a part of the negative electrode metal foil 25.

  In the negative electrode 24, the opposite side of the first side (upper side) 25c provided with the negative current collecting tab 32 is the second side 25e, and the pair of sides connecting the first side 25c and the second side 25e is the first side. 3 side 25f. In the separator 27, a side disposed on the positive electrode current collecting tab 31 and negative electrode current collecting tab 32 side is a first side 27c, and a side opposite to the first side 27c is a second side 27e. In the separator 27, a pair of sides connecting the first side 27c and the second side 27e are defined as a third side 27f.

  The lengths of the two adjacent sides of the negative electrode active material layer 26 (the length in the longitudinal direction and the length in the short direction) are the lengths of the two sides of the positive electrode active material layer 23 (the length in the longitudinal direction). The length in the direction and the length in the short direction). That is, the negative electrode active material layer 26 is set to a size that can cover the surface of the positive electrode active material layer 23. Further, since the positive electrode uncoated portion 22d and the negative electrode uncoated portion 25d are formed around the positive electrode active material layer 23 and the negative electrode active material layer 26, the separator 27 is formed on the surface of the negative electrode active material layer 26 and the positive electrode. Both surfaces of the active material layer 23 can be covered.

  As shown in FIG. 1, the positive electrode 21, the negative electrode 24, and the separator 27 are arranged at positions where the positive electrode current collecting tabs 31 are arranged in a line along the stacking direction and do not overlap with the positive electrode current collecting tabs 31. The negative electrode current collecting tabs 32 are stacked so as to be arranged in a line along the stacking direction. The electrode assembly 14 includes a tab-side end surface 36 formed by gathering the first sides 22c, 25c, and 27c. In the tab-side end surface 36, the positive current collecting tabs 31 and the negative current collecting tabs 36 are provided. The electric tab 32 is bent in a state of being collected (bundled) within a range from one end to the other end in the stacking direction of the electrode assembly 14. The positive current collecting tabs 31 are electrically connected by welding the portions where the positive current collecting tabs 31 are overlapped, and the positive electrode conductive member 41 a is connected to the positive current collecting tab 31. A positive electrode terminal 41 b for taking out electricity from the electrode assembly 14 is connected to the positive electrode conductive member 41 a.

  Similarly, the negative electrode current collecting tabs 32 are electrically connected by welding the portions where the negative electrode current collecting tabs 32 overlap, and the negative electrode current collecting tabs 32 are connected to the negative electrode conductive members 42a. A negative electrode terminal 42b for taking out electricity from the electrode assembly 14 is connected to the negative electrode conductive member 42a. The positive terminal 41b and the negative terminal 42b penetrate the lid 13 and protrude out of the case 11, and the positive terminal 41b and the negative terminal 42b are insulated from the lid 13 by the insulating ring 13b.

  When the length of the electrode assembly 14 along the stacking direction is the thickness of the electrode assembly 14, the thickness of the electrode assembly 14 is adjusted so that the thickness is slightly smaller than the inner dimension of the case 11. The electrode assembly 14 includes a bottom surface 37 in which the second sides 22e, 25e, and 27e are gathered together, and the bottom surface 37 is located on the opposite side of the tab-side end surface 36 with the electrode assembly 14 interposed therebetween. . Furthermore, the electrode assembly 14 includes a pair of side surfaces 38 in which the third sides 22f, 25f, and 27f are gathered together. The pair of side surfaces 38 are two surfaces of the electrode assembly 14 that are connected to the bottom surface 37 and exclude both the flat surfaces 44 in the stacking direction.

  In the electrode assembly 14, a large number of positive electrodes 21, negative electrodes 24, and separators 27 are held in a mutually positioned state by a first holding tape 45 and a second holding tape 47. The electrode assembly 14 is held by the first holding tape 45 and the second holding tape 47 so that the electrode assembly 14 does not disassemble in the stacking direction when the electrode assembly 14 is inserted into the container 12 from the opening 12a. This is to improve the insertability.

  The electrode assembly 14 is manufactured so that the entire surface of the positive electrode active material layer 23 faces the negative electrode active material layer 26 with the separator 27 interposed therebetween, from the viewpoint of suppressing a decrease in energy density in the secondary battery 10. Yes. Further, the positive electrode active material layer 23 and the negative electrode active material layer 26 are manufactured so as not to face each other beyond the edge of the separator 27. In order to prevent the electrode assembly 14 thus manufactured with high precision from being displaced in the stacking direction or the direction along the flat plane 44, the electrode assembly 14 includes the first holding tape 45 and the second holding tape. 47. The electrode assembly 14 is held by the first holding tape 45 and the second holding tape 47 after the thickness is adjusted.

  Two first holding tapes 45 are attached to the tab side end surface 36 side and the bottom surface 37 side of the electrode assembly 14 from the tab side end surface 36 side and the bottom surface 37 side. The first holding tape 45 has a strip shape and is attached in a U-shaped cross section. The first holding tape 45 is covered so that both ends in the longitudinal direction are attached to the both flat surfaces 44 of the electrode assembly 14 and part of the tab-side end surface 36 and the bottom surface 37. In the electrode assembly 14, the two first holding tapes 45 are separated in the width direction of the electrode assembly 14 when the direction perpendicular to the stacking direction along the tab side end surface 36 and the bottom surface 37 is defined as the width direction.

  A second holding tape 47 is attached to each side surface 38 that is both sides in the width direction of the electrode assembly 14 so as to cover each side surface 38. Each second holding tape 47 has a strip shape and is attached in a U-shaped cross section. The second holding tape 47 is covered so that both ends in the longitudinal direction are attached to the both flat surfaces 44 of the electrode assembly 14 and part of the side surface 38 is straddled. The first and second holding tapes 45 and 47 are made of polypropylene (PP) or polyfinylene sulfide (PPS) with an adhesive layer provided on one surface, and are made of a material that is not easily torn. The

Next, the electrode assembly manufacturing apparatus 50 will be described.
The electrode assembly manufacturing apparatus 50 is used for adjusting the thickness of the electrode assembly 14 and for attaching the first holding tape 45 and the second holding tape 47 to the electrode assembly 14 after the thickness adjustment.

  As shown in FIGS. 4 and 6, the electrode assembly manufacturing apparatus 50 includes a pair of clamping members 51 and 61 made of a metal plate, and a load applying apparatus 66 that applies a load in the stacking direction to the electrode assembly 14. Is provided. Of the pair of sandwiching members 51 and 61, the sandwiching member disposed on the lower side and supporting the electrode assembly 14 is defined as one sandwiching member 51, and the sandwiching member placed on the flat surface 44 of the electrode assembly 14 is the other. The clamping member 61 is described.

  The pair of sandwiching members 51 and 61 have first mating surfaces 52a and 62a on one side surface extending in the longitudinal direction, respectively, and second mating surfaces 52b and 62b on the other side surface. The lengths of the first mating surfaces 52 a and 62 a along the longitudinal direction of the sandwiching member 51 are longer than the lengths of the second mating surfaces 52 b and 62 b along the longitudinal direction of the sandwiching member 51. It is the length along the short direction of the clamping members 51 and 61, and the length between the first mating surfaces 52a and 62a and the second mating surfaces 52b and 62b is the shortest distance K1.

  As shown in FIG. 5, the length between the tab-side end surface 36 and the bottom surface 37 of the electrode assembly 14 is the shortest distance K2. In this case, the shortest distance K1 between the clamping members 51 and 61 is the same as the shortest distance K2 of the electrode assembly 14.

  As shown in FIG. 4, the sandwiching members 51, 61 include a pair of projecting portions 54, 64 on both ends in the longitudinal direction, and each projecting portion 54, 64 extends in the short direction of the sandwiching members 51, 61. It is provided at intervals. Of the pair of clamping members 51, 61, one clamping member 51 is provided with a female screw portion 55 as a holding member near the tip of each projection 54, and the other clamping member 61 is near the tip of each projection 64. An insertion hole 56 is provided.

  The electrode assembly manufacturing apparatus 50 includes a resin bolt 57 as a holding member, and the bolt 57 is inserted in a state where the electrode assembly 14 is sandwiched between one clamping member 51 and the other clamping member 61. It is inserted into the hole 56 and screwed into the female screw portion 55. The state where the electrode assembly 14 is sandwiched between the clamping members 51, 61 can be held by screwing the bolt 57 to the female thread portion 55, and the distance between the pair of clamping members 51, 61 can be fixed. Yes.

  The clamping members 51 and 61 have end surfaces 53 and 63 that are positioned between the projecting portions 54 and 64 that face each other in the lateral direction and extend in the lateral direction. In the clamping members 51 and 61, it is the length along a longitudinal direction, and let the length between a pair of end surfaces 53 and 63 be the shortest distance K3.

  As shown in FIG. 5, the length between the pair of side surfaces 38 in the electrode assembly 14 is the shortest distance K4. In this case, the shortest distance K3 between the clamping members 51 and 61 is shorter than the shortest distance K4 of the electrode assembly 14.

  As shown in FIG. 4, the sandwiching members 51, 61 are recessed from the first mating surfaces 52 a, 62 a toward the side surfaces of the two projecting portions 54, 64 connected to the first mating surfaces 52 a, 62 a. The recesses 58 and 68 are provided. The sandwiching members 51 and 61 include second recesses 59 and 69 that are recessed from the second mating surfaces 52b and 62b toward the two projecting portions 54 and 64 connected to the second mating surfaces 52b and 62b. . The sandwiching members 51 and 61 include third recesses 60 and 70 that are recessed from the tips of the projecting portions 54 and 64 facing in the lateral direction toward the end surfaces 53 and 63.

  As shown in FIG. 6, the load applying device 66 included in the electrode assembly manufacturing apparatus 50 includes an electrode assembly in a state where the electrode assembly 14 is sandwiched between one clamping member 51 and the other clamping member 61. A load is applied to the electrode assembly 14 from the other holding member 61 placed on the three-dimensional body 14. The load applying device 66 includes a pressing member 66 a that is a pressing device, and the pressing member 66 a can move forward and backward with respect to the holding members 51 and 51. The load applied to the electrode assembly 14 by the load applying device 66 is managed by the pressing member 66a. Further, when a load is applied to the electrode assembly 14 by the load applying device 66, the interval between the pair of clamping members 51 determined by the load application is fixed and maintained by screwing the bolt 57 into the female thread portion 55. Be able to.

Next, the manufacturing method of the electrode assembly 14 will be described together with the operation.
First, the lamination process of the electrode assembly 14 is performed. One clamping member 51 is set, and the positive electrode 21, the separator 27, and the negative electrode 24 are laminated on the clamping member 51 by a laminating device (not shown). During the lamination, the positive electrode 21, the negative electrode 24, and the separator 27 have the first sides 22c, 25c, and 27c along the first mating surface 52a of the sandwiching member 51, and the second sides 22e, 25e, 27e is laminated along the second mating surface 52b. The positive electrode 21, the negative electrode 24, and the separator 27 are stacked so that their third sides 22 f, 25 f, 27 f are parallel to the end surface 53 at positions protruding from both end surfaces 53. By being laminated in this way, the positive electrode active material layer 23 of the positive electrode 21 and the negative electrode active material layer 26 of the negative electrode 24 are opposed to each other with the separator 27 interposed therebetween, and the positive electrode is formed from the edge of the separator 27. The active material layer 23 and the negative electrode active material layer 26 are laminated so as not to protrude.

  As a result, the electrode assembly 14 is formed on one clamping member 51. The electrode assembly 14 has a tab-side end surface 36 that is flush with the first mating surface 52a and a bottom surface 37 that is the second mating surface. It is flush with 52 b and both side surfaces 38 protrude from both end surfaces 53. When this position is a predetermined position, in a state where the electrode assembly 14 is formed at a predetermined position of the clamping member 51, a pair of protruding portions 54 protrude from both side surfaces 38 of the electrode assembly 14, and the female screw portion 55 Is exposed.

  Next, as shown in FIG. 5, a step of sandwiching the electrode assembly 14 between the pair of sandwiching members 51 and 61 from the stacking direction is performed. In a state where the electrode assembly 14 is formed at a predetermined position on the holding member 51, the other holding member 61 is placed on the flat surface 44 of the electrode assembly 14. The other clamping member 61 has a first mating surface 62 a flush with the tab side end surface 36, a second mating surface 62 b flush with the bottom surface 37, and both end surfaces 63 on both sides of the electrode assembly 14. Mounted in a state of being retreated from the surface 38. The other holding member 61 is placed such that a pair of protrusions 64 protrude from both side surfaces 38 of the electrode assembly 14 and the insertion hole 56 is positioned outward from the side surface 38.

  Then, a bolt 57 is inserted into each insertion hole 56 of the other clamping member 61, and the bolt 57 is screwed into each female screw portion 55 of the one clamping member 51. Then, the electrode assembly 14 can be clamped from both sides in the stacking direction by the pair of clamping members 51 and 61. Note that the bolt 57 is screwed into a state where it can be tightened without being screwed into the female screw portion 55 strongly. Therefore, the movement of the pair of clamping members 51 and 61 in the direction along the flat plane 44 is restricted by the screwing of the bolt 57 to the female screw portion 55. Further, in a state where the electrode assembly 14 is sandwiched between the pair of sandwiching members 51 and 61, the two first concave portions 58 and 68 of the sandwiching members 51 and 61 expose the flat surface 44 near the tab side end surface 36. Due to the two second recesses 59 and 69, the flat surface 44 near the bottom surface 37 is exposed. Further, the flat surfaces 44 near both side surfaces 38 are exposed by the third recesses 60 and 70 of the clamping members 51 and 61.

Next, a step of applying a load to the sandwiched electrode assembly 14 in the stacking direction is performed.
As shown in FIG. 6, the pressing member 66 a of the load applying device 66 advances toward the other holding member 61, and the load applying device 66 is predetermined in the stacking direction to the electrode assembly 14 via the other holding member 61. Apply the load. Then, the other holding member 61 moves toward the one holding member 51 along the axial direction of the bolt 57 and is pressed against the electrode assembly 14. As a result, the thickness of the electrode assembly 14 decreases. Then, after the electrode assembly 14 is stabilized, the bolts 57 are tightened with the load applied by the load applying device 66. Then, the electrode assembly 14 is sandwiched between the pair of sandwiching members 51 and 61, and the distance between the pair of sandwiching members 51 and 61, that is, the thickness of the electrode assembly 14 is fixed by the bolt 57 and the female screw portion 55. Maintained. As a result, the thickness of the electrode assembly 14 is maintained in a compressed state, and when the positive electrode 21, the negative electrode 24, and the separator 27 are maintained in a compressed state, the electrode assembly 14 is compressed with time. The springback is gradually reduced.

  Next, in the state where the electrode assembly 14 is clamped by the pair of clamping members 51, 61 by the screwing of the female screw portion 55 and the bolt 57, that is, in the state where the distance between the pair of clamping members 51, 61 is maintained. The process of canceling the provision of That is, with the bolt 57 still screwed into the female thread portion 55, the pressing member 66a of the load applying device 66 is retracted to release the load applied to the electrode assembly 14.

  As shown in FIG. 7, even when the load application by the load application device 66 is released, the distance between the pair of clamping members 51 and 61 is maintained by the screwing of the bolt 57 and the female screw portion 55. For this reason, even after releasing the load, the electrode assembly 14 continues to be in a compressed thickness, and the positive electrode 21, the negative electrode 24, and the separator 27 are adapted to the compressed shape, and the spring back is released. It will be gradually reduced.

  Next, while maintaining the clamping state with the bolt 57 and the female screw portion 55, the load applying device 66 is removed, the load applying device 66 and the electrode assembly 14 are placed separately, and the holding tapes 45 and 47 are attached to the electrode assembly 14. The process of sticking is performed.

  As shown in FIGS. 8 and 9, the first holding tape 45 is attached to the flat surface 44 near the tab side end surface 36 exposed from the two first recesses 58 and 68, and two locations on the tab side end surface 36 side are provided. The electrode assembly 14 is held in all directions along the stacking direction and the flat plane 44. The first holding tape 45 is also attached to the flat surface 44 near the bottom surface 37 exposed from the two second recesses 59 and 69, and the electrode assembly 14 is placed in the stacking direction and at the two positions on the bottom surface 37 side. Hold in all directions along the plane 44. Further, the second holding tape 47 is attached to the flat surfaces 44 near the both side surfaces 38 exposed from the third recesses 60, 70, and the electrode assembly 14 is placed in the stacking direction and the flat surfaces 44 from both side surfaces 38. Hold in all directions along.

  Then, after a predetermined time has elapsed since the load is applied to the electrode assembly 14, a step of releasing the clamping by the bolt 57 and the female screw portion 55 is performed. That is, the step of releasing the bolt 57 from the female screw portion 55 and releasing the state in which the interval between the pair of holding members 51 and 61 is fixed is performed, and the state in which the electrode assembly 14 is held is released. As a result, the electrode assembly 14 held by the first holding tape 45 and the second holding tape 47 is manufactured.

According to the above embodiment, the following effects can be obtained.
(1) By fixing the distance between the pair of clamping members 51 and 61 by screwing the bolt 57 and the female screw portion 55, the electrode assembly 14 is maintained at a compressed thickness even after the load is released. The In order to reduce the spring back of the electrode assembly 14, it is effective to continue the compressed state of the electrode assembly 14 for a predetermined time. In the embodiment, the distance between the pair of clamping members 51 and 61 can be fixed by the bolts 57 regardless of whether or not a load is applied, and the state where the electrode assembly 14 is compressed can be continued. Therefore, after the first holding tape 45 and the second holding tape 47 are attached to the electrode assembly 14, when the holding by the pair of holding members 51 and 61 is released after a predetermined time has elapsed, the positive electrode 21, the negative electrode 24, And the spring back of the separator 27 can be suppressed. Therefore, it is possible to suppress a strong force from being applied to the first holding tape 45 and the second holding tape 47 due to the spring back. As a result, it is not necessary to use a strong adhesive tape for the first holding tape 45 and the second holding tape 47, and the active material is not lost from the positive electrode active material layer 23 or the negative electrode active material layer 26 due to a strong tension. .

  (2) The first holding tape 45 and the second holding tape 47 can suppress the displacement of the electrode assembly 14 in the stacking direction and in all directions along the flat plane 44. Therefore, when the electrode assembly 14 is inserted into the container 12, the electrode assembly 14 is not disassembled in the stacking direction, and the insertion property is improved. Further, the entire surface of the positive electrode active material layer 23 can be maintained facing the negative electrode active material layer 26 with the separator 27 interposed therebetween, and a reduction in energy density of the secondary battery 10 can be suppressed. Furthermore, the positive electrode active material layer 23 and the negative electrode active material layer 26 do not cross the edge of the separator 27, and a short circuit can be suppressed.

  (3) Even if the electrode assembly 14 is sandwiched between the pair of clamping members 51 and 61 and the female screw portion 55 and the bolt 57 are screwed together, the first concave portions 58 and 68, the second concave portions 59 and 69, and the third A part of the electrode assembly 14 can be exposed by the recesses 60 and 70. Therefore, the first holding tape 45 and the second holding tape 47 can be attached to the electrode assembly 14 while the electrode assembly 14 is sandwiched between the pair of holding members 51 and 61. Therefore, when the 1st holding tape 45 and the 2nd holding tape 47 are stuck on the electrode assembly 14 laminated | stacked accurately, it can suppress that the electrode assembly 14 shifts | deviates to the direction along the flat surface 44. FIG.

  (4) The electrode assembly manufacturing apparatus 50 includes a load applying device 66 in addition to the pair of clamping members 51 and 61. Therefore, after the electrode assembly 14 is sandwiched between the pair of sandwiching members 51 and 61, a load can be applied to the electrode assembly 14 by the load applying device 66, and the electrode assembly using the electrode assembly manufacturing apparatus 50 can be applied. The solid 14 can be easily compressed. Further, it is not necessary to compress the electrode assembly 14 with the bolt 57, and when the bolt 57 and the female screw portion 55 are screwed together, a strong force does not act on the screwed portion, so that the generation of foreign matter can be suppressed. .

  (5) For example, if the bolt 57 is made of metal, there is a possibility that foreign matter may be generated due to the metal rubbing when the bolt 57 is screwed into the female screw portion 55. However, although the female screw portion 55 is made of metal, the bolt 57 is made of resin, so that the generation of foreign matters at the time of screwing can be suppressed, and foreign matters can be prevented from entering the electrode assembly 14.

  (6) A state in which a load is applied to the electrode assembly 14 by applying a load to the electrode assembly 14 by the load applying device 66 and then holding the pair of holding members 51 and 61 between the bolt 57 and the female screw portion 55. Can be retained. Therefore, the electrode assembly 14 and the clamping members 51 and 61 can be separated from the load applying device 66 and placed separately. Since the springback is reduced with time, the electrode assembly 14 and the load applying device 66 can be placed separately so that the load applying device 66 suppresses the springback while reducing the springback. Can be avoided.

In addition, you may change the said embodiment as follows.
In the embodiment, the bolt 57 is made of resin, but the material of the bolt 57 is not limited to resin, and may be made of metal.

  In the embodiment, the holding member is embodied as the female screw portion 55 and the bolt 57, but is not limited thereto. For example, the pair of sandwiching members 51 and 61 may be held in a state of being wrapped and sandwiched between, for example, rubber and an annular band, or the pair of sandwiching members 51 and 61 may be sandwiched by a U-shaped clip. It may be held.

  ○ As a holding member, a male screw is erected from the protruding portion 54 of one clamping member 51, and a nut is screwed into the male screw inserted into the insertion hole 56 of the other clamping member 61 to clamp the clamping members 51, 61. You may make it do.

The load applying device is not limited to the press device, and may be a simple weight, or may apply a predetermined load by torque management of the bolt 57.
○ The positions of the protrusions 54 and 64 may be changed. For example, as shown in FIG. 10, the protruding portions 54 and 64 may be protruded from the first mating surfaces 52a and 62a and the second mating surfaces 52b and 62b of the holding members 51 and 61, respectively. In this case, since the positive electrode current collection tab 31 and the negative electrode current collection tab 32 protrude from the protrusions 54 and 64 on the first mating surfaces 52a and 62a side, the pair of protrusions 54 and 64 are formed of the positive electrode current collection tabs. 31 and the negative electrode current collection tab 32 are arranged inside.

  When configured in this manner, the projecting portions 54 and 64 project so as to be orthogonal to the first mating surfaces 52a and 62a and the second mating surfaces 52b and 62b extending in the longitudinal direction of the holding members 51 and 61. For this reason, when the bolt 57 is screwed into the female screw portion 55 of the protruding portion 54, the clamping members 51 and 61 are less likely to warp in the longitudinal direction.

In the clamping members 51 and 61, the position where the recess is formed may be changed as appropriate.
The number of positive electrodes 21 and negative electrodes 24 constituting the electrode assembly 14 may be changed as appropriate.

  In the embodiment, the positive electrode 21 has the positive electrode active material layer 23 on both sides of the positive electrode metal foil 22, but may have the positive electrode active material layer 23 only on one side of the positive electrode metal foil 22. . Similarly, although the negative electrode 24 has the negative electrode active material layer 26 on both surfaces of the negative electrode metal foil 25, the negative electrode active material layer 26 may be provided on only one surface of the negative electrode metal foil 25.

  O You may actualize as a nickel-hydrogen secondary battery as an electrical storage apparatus, or an electric double layer capacitor.

  DESCRIPTION OF SYMBOLS 14 ... Electrode assembly, 21 ... Positive electrode, 23 ... Positive electrode active material layer, 24 ... Negative electrode, 26 ... Negative electrode active material layer, 27 ... Separator, 38 ... Side surface, 44 ... Flat surface, 45 ... 1st holding tape, 47 ... second holding tape, 50 ... electrode assembly manufacturing apparatus, 51, 61 ... clamping member, 54,64 ... projecting part, 55 ... female screw part as holding member, 57 ... bolt as holding member, 58,68 ... 1st recessed part, 59, 69 ... 2nd recessed part, 60, 70 ... 3rd recessed part, 66 ... Load application apparatus, 66a ... Pressing member.

Claims (5)

An apparatus for manufacturing an electrode assembly in which a positive electrode having an active material layer and a negative electrode are laminated with a separator interposed therebetween,
A pair of clamping members that sandwich the electrode assembly from both flat surfaces in the stacking direction;
A holding member capable of holding a pair of clamping members in a state of sandwiching the electrode assembly, and fixing a distance between the pair of clamping members;
An apparatus for manufacturing an electrode assembly, comprising: a recess provided in each of the clamping members and exposing a part of each of the flat surfaces of the electrode assembly.   2. The electrode assembly according to claim 1, further comprising a pressing member capable of moving forward and backward relative to the clamping member, wherein the pressing member includes a load applying device that applies a load in the stacking direction to the electrode assembly via the clamping member. Manufacturing equipment.   Each of the clamping members includes a plurality of projecting portions that project along the flat surface and away from the side surface connected to the flat surface in a state where the electrode assembly is sandwiched, and the holding member is one clamping member 3. The electrode assembly according to claim 1, further comprising: a female thread portion provided in the projecting portion of the first and second bolts, and a bolt inserted into the projecting portion of the other holding member and screwed into the female thread portion. manufacturing device.   4. The apparatus for manufacturing an electrode assembly according to claim 3, wherein each of the clamping members is made of metal, and the bolt is made of resin. A method of manufacturing an electrode assembly in which a positive electrode and a negative electrode are stacked with a separator interposed therebetween,
Laminating the positive electrode and the negative electrode with the separator interposed therebetween;
Sandwiching the electrode assembly from a pair of clamping members from both flat surfaces in the stacking direction;
Applying a load in the stacking direction to the electrode assembly sandwiched between a pair of sandwiching members;
Fixing the interval between the pair of sandwiching members with a holding member;
Releasing the application of the load while maintaining a distance between the pair of sandwiching members;
A step of sticking a holding tape to both the flat surfaces across the side surfaces connected to both the flat surfaces of the electrode assembly from the recesses of the pair of holding members while maintaining the distance between the pair of the holding members;
And a step of releasing fixing of the interval between the pair of clamping members after a predetermined time has elapsed.