JP6398529B2 - Method for manufacturing electrode storage separator - Google Patents

Description

  The present invention relates to a method for manufacturing an electrode storage separator in which a rectangular sheet-like electrode is stored between separator members facing each other, and the separator member has a joint portion that joins portions protruding from the sides of the electrode.

  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. As this type of secondary battery, for example, a battery having a stacked electrode assembly in which a rectangular sheet-like positive electrode, a rectangular sheet-like negative electrode, and a separator for insulating them are alternately stacked. Are known. However, since the laminated structure undergoes a manufacturing process in which the positive electrode, the negative electrode, and the separator are sequentially stacked, the number of stacking processes increases. Therefore, there are problems that the tact time of production is long and the productivity is not good. Thus, for example, an electrode storage separator in which a positive electrode is previously stored in a bag-like separator is known.

  As an example of the manufacturing method of such an electrode storage separator, electrodes are arranged in advance between the facing separator members, and the portions protruding from the sides constituting the outer shape of the electrodes in the pair of separator members are There is a method of sandwiching and welding with a welding tool (for example, see Patent Document 1). In such a manufacturing method, when the separator members are welded together, it is necessary to weld only the separator member without sandwiching the electrodes between the welding tools.

  In the electrode storage separator manufacturing facility, the position where the welding tool contacts the separator member is mechanically determined, so it is almost constant, but the electrode sandwiched between the separator members is placed due to misalignment, etc. Misalignment is likely to occur. For this reason, arrangement | positioning of an electrode is performed so that a fixed clearance may be vacated from the position where a welding tool contacts a separator member.

  As a result, the size of the electrode that can be stored in the electrode storage separator is reduced by the amount of clearance, which leads to a decrease in the energy density of the secondary battery. Therefore, for example, as in Patent Document 2, a part of the pair of separator members is joined in advance, and the electrode is inserted between the pair of separator members that are partly bag-shaped. It is also conceivable to reduce clearance by avoiding pinching with welding tools.

  In the manufacturing method of the bag-shaped separator (electrode storage separator) disclosed in Patent Document 2, as shown in FIG. 9, two adjacent separator fusion sides 82 and 83 among the four separator sides of the porous film 81 are used. Heat-sealed portions 82a and 83a are formed. One separator fusion side 82 is fused by three thermal fusion portions 82a, and the other separator fusion side 83 is fused by a central thermal fusion portion 83a.

  Further, the insertion port sides 84 and 85 that are the remaining two separator sides constitute an insertion port 88 that allows the electrode 90 to be inserted into the bag-shaped separator 80. In addition, a heat fusion part 84a is formed in a part of one insertion port side part 84. The insertion port 88 includes a first insertion port 88a formed on the side of one insertion port side portion 84 and a second insertion port 88b formed on the side of the other insertion port side portion 85. .

  Then, in a state where a plurality of heat-sealing portions 82a, 83a, 84a are formed in advance and are partially bag-shaped, the electrode 90 is connected to the first insertion port 88a and the second insertion port 88b from the short side. And are inserted into the bag-shaped separator 80 so as to straddle both insertion openings. Subsequently, the electrode 90 in a state where the short side is partially inserted and tilted is rotated and inserted until the long side and the short side of the electrode 90 come into contact with the heat fusion portions 82a, 83a, and 84a. Thereafter, when a heat fusion part is formed in the insertion port side 84 or the insertion port side 85, the electrode 90 is accommodated between the pair of porous films 81, and the bag-shaped separator 80 is manufactured.

JP 2013-178951 A Japanese Patent No. 5287255

  However, in the manufacturing method of Patent Document 2, when the electrode 90 is inserted between the pair of porous films 81, the active material layer of the electrode 90 may be rubbed against the inner surface of the porous film 81, and the electrode 90 is damaged. There is a risk of receiving.

  The present invention has been made to solve the above-described problems, and the object thereof is to reduce the clearance between the joint and the electrode and to suppress the electrode from being damaged by the separator member. It is providing the manufacturing method of an electrode storage separator.

  In the electrode storage separator manufacturing method for solving the above-described problems, a rectangular sheet-like electrode is stored between the separator members facing each other, and the portions of the separator member that protrude from the sides of the electrode are joined to each other. In the manufacturing method of the electrode storage separator having the joined portion, the long separator members facing each other and having the gap between the opposing surfaces widened, the separator members are arranged on the lower side in the vertical direction. A first joining step in which a part is joined to form a first joined part along a side of the electrode; and the electrode is placed between the opposing surfaces of the separator member on the upper side in the vertical direction from the first joined part. An electrode placement step in which the edge along the lower side of the electrode in the vertical direction is brought into contact with the inner end of the first joint, and is positioned above the first joint in the vertical direction; One and summarized in that comprises a second bonding step of forming a second junction with at least joining said separator members together in a portion along the opposite side edges of the electrode.

  According to this, in a 1st joining process, a part of the vertical direction lower side of the separator members in the state which extended the space | interval is joined, and it joins by a 1st junction part. For this reason, even after the first joining step, the pair of separator members is in a state where the interval between the opposing surfaces is widened in the vertical direction above the first joining portion. For this reason, even if an electrode is dropped in the case of an electrode arrangement | positioning process, it can suppress that an electrode contacts the opposing surface of a separator member, and can suppress that an electrode receives damage by a separator member.

  In the electrode placement step, the edge along the side of the electrode is brought into contact with the inner end of the first joint portion. For this reason, there is almost no clearance between the inner end of the first joint and the edge of the electrode. Therefore, when the electrode storage separator of the same area is used as a reference, the clearance is eliminated on at least one side as compared to the case where there is a clearance between all sides of the electrode and the joint portion along the side. As a result, the external size of the electrode can be increased, and the energy density can be increased in the power storage device in which the electrode storage separator is used.

In addition, regarding the method for manufacturing the electrode storage separator, the electrode may be a positive electrode.
According to this, the electrode storage separator insulates between the positive electrode and the negative electrode. Of the positive electrode and the negative electrode, the positive electrode has a smaller outer size than the negative electrode. If the outer size of the positive electrode can be increased, the facing area of the active material layer can be increased without changing the outer size of the negative electrode in a limited power storage device case, thereby increasing the energy density. be able to.

  Moreover, about the manufacturing method of an electrode storage separator, after joining the said separator members in the part along the remaining edge | side of an electrode and forming a junction part, the cutting process of cut | disconnecting a pair of said separator member is included. May be.

According to this, the electrode storage separator can be manufactured one by one.
Moreover, about the manufacturing method of an electrode storage separator, a pair of said separator member is extended in an up-down direction in the state in which a longitudinal direction becomes diagonal with respect to a perpendicular direction, and is an electrode along the longitudinal direction of the said separator member in a said 1st joining process. The first joint may be formed along one side and another side that intersects the one side and extends in the short direction of the separator member.

  According to this, the 1st junction part is formed in the L shape to a separator member. Moreover, since the separator member extending obliquely with respect to the vertical direction is formed in an L shape, the edge of the electrode can be received by the corner portion of the L shape at the first joint portion, and the displacement of the electrode can be regulated. it can.

  ADVANTAGE OF THE INVENTION According to this invention, it can suppress that an electrode receives damage by a separator member, reducing the clearance between a junction part and an electrode.

The perspective view which shows the secondary battery of embodiment. The disassembled perspective view which shows the component of an electrode assembly. (A) is a top view which shows the electrode storage separator of embodiment, (b) is a top view which shows the electrode storage separator of a comparative example. 4A is a sectional view taken along the line 4a-4a of FIG. 3A showing the electrode storage separator of the embodiment, and FIG. 4B is a sectional view taken along the line 4b-4b of FIG. 3B showing the electrode storage separator of the comparative example. (A) is a schematic diagram showing a state in which the distance between a pair of separator members is widened, (b) is a schematic diagram showing a state in which a first welded portion is formed, and (c) is a state in which a positive electrode is dropped. (D) is a schematic diagram showing a state in which a distance between a pair of separator members is narrowed, (e) is a schematic diagram showing a state in which a second welded portion is formed, and (f) is a third welded portion. The schematic diagram which shows the state which formed. The top view which shows the state which welded a pair of separator member. The top view which shows another example of a 1st welding part. The top view which shows the manufacturing method of another example. The figure which shows background art.

Hereinafter, an embodiment embodying an electrode storage separator will be described with reference to FIGS.
As shown in FIG. 1, the secondary battery 10 includes a metal case 11 constituting an outer shell. The case 11 includes a bottomed rectangular parallelepiped case main body 12 having an opening on one surface and a lid 13 that closes the opening. The case 11 contains an electrode assembly 14 and an electrolytic solution (not shown) as an electrolyte. The secondary battery 10 is a lithium ion battery.

  As shown in FIG. 2, the electrode assembly 14 has a stacked configuration in which an electrode storage separator 27 that stores a positive electrode 21 as an electrode and a plurality of negative electrodes 24 are alternately stacked. The positive electrode 21 has a rectangular sheet-like positive electrode metal foil (in this embodiment, an aluminum foil) 22 and a rectangular positive electrode active material layer 23 provided on both surfaces of the positive electrode metal foil 22. The positive electrode active material layers 23 on both surfaces of the positive electrode metal foil 22 have the same planar shape and the same thickness, and face each other with the positive electrode metal foil 22 in between. The positive electrode 21 has a positive electrode uncoated portion 22d in which the positive electrode active material layer 23 is not provided and the positive electrode metal foil 22 is exposed along the first side 22c.

  And in the positive electrode 21, the positive electrode tab 31 protrudes in a part of 1st side 22c used as one side (long side) of the positive electrode uncoated part 22d. The positive electrode tab 31 extends with a constant width along the protruding direction from the first side 22c of the positive electrode uncoated portion 22d. In the positive electrode 21, a long side that is opposite to the first side 22c provided with the positive electrode tab 31 is defined as a second side 22e. Further, in the positive electrode 21, of the pair of sides (short sides) connecting the first side 22c and the second side 22e, one short side is defined as the first side side 22f, and the other side is defined as the second side. The side is 22 g.

  The negative electrode 24 includes a rectangular sheet-like negative electrode metal foil (copper foil in the present embodiment) 25 and a rectangular negative electrode active material layer 26 provided on both surfaces of the negative electrode metal foil 25. The negative electrode active material layers 26 on both sides of the negative electrode metal foil 25 have the same planar shape and the same thickness. The negative electrode 24 has a negative electrode uncoated portion 25d in which the negative electrode active material layer 26 is not provided and the negative electrode metal foil 25 is exposed along the first side 25c.

  And in the negative electrode 24, the negative electrode tab 32 protrudes in a part of 1st side 25c used as one side (long side) of the negative electrode uncoated part 25d. The negative electrode tab 32 extends with a constant width along the protruding direction from the first side 25c of the negative electrode uncoated portion 25d. In the negative electrode 24, a long side that is opposite to the first side 25c provided with the negative electrode tab 32 is defined as a second side 25e. Further, in the negative electrode 24, one of the pair of sides (short sides) connecting the first side 25c and the second side 25e is the first side 25f, and the other side is the second side. The side is 25 g.

  In the bag-shaped electrode storage separator 27, one side (long side) extending along the first side 22c of the positive electrode 21 is defined as a first side 27c, the opposite side of the first side 27c, and the first side of the positive electrode 21 A side (long side) extending along the second side 22e is defined as a second side 27e. In the electrode storage separator 27, a side (short side) that connects the first side 27c and the second side 27e and extends along the first side 22f of the positive electrode 21 is defined as a first side 27f. A side (short side) extending along the second side 22g is defined as a second side 27g.

  The negative electrode 24 and the electrode storage separator 27 are arranged such that the positive electrode tabs 31 are arranged in a row along the stacking direction, and the negative electrode tabs 32 are arranged in a row along the stacking direction at a position not overlapping the positive electrode tab 31. Are laminated as shown. The positive electrode tab 31 and the negative electrode tab 32 are 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. Each positive electrode tab 31 is electrically connected by welding a portion where the positive electrode tabs 31 overlap, and a positive electrode terminal 43 is electrically connected to the positive electrode tab 31. Similarly, the negative electrode tabs 32 are electrically connected by welding the portions where the negative electrode tabs 32 overlap, and the negative electrode tabs 46 are welded to the negative electrode tabs 32.

  Here, in the positive electrode 21 and the negative electrode 24, the lengths of the two adjacent sides of the negative electrode active material layer 26 (the length along the long side and the length along the short side) are the positive electrode active material layer 23. Are set longer than the lengths of the two adjacent sides (the length along the long side and the length along the short side). That is, the negative electrode active material layer 26 is set to a size that can cover the entire surface of the positive electrode active material layer 23. The lengths of the first side 25c and the second side 25e of the negative electrode 24 are set longer than the lengths of the first side 22c and the second side 22e of the positive electrode 21. Furthermore, the length of the first side 25 f and the second side 25 g of the negative electrode 24 is set longer than the length of the first side 22 f and the second side 22 g of the positive electrode 21. That is, the size of the negative electrode 24 in plan view is slightly larger than the size of the positive electrode 21 in plan view.

  The positive electrode 21 and the negative electrode 24 formed in this way are formed on the entire surface of the positive electrode active material layer 23 and the negative electrode active material layer 26 via the electrode storage separator 27 from the viewpoint of suppressing a decrease in energy density in the secondary battery 10. They are stacked so as to face each other.

Next, the electrode storage separator 27 will be described in detail.
The electrode storage separator 27 is formed in a bag shape by joining a pair of separator members 28 by thermal welding. The pair of separator members 28 face each other. Further, the pair of separator members 28 has a rectangular shape having a size that covers both surfaces of the positive electrode 21 and the same size. The electrode storage separator 27 has a storage portion 27a formed of a pair of separator members 28, and the positive electrode 21 is stored in the storage portion 27a. The pair of separator members 28 include a protruding portion 30 that protrudes from the first side 22c, the second side 22e, the first side 22f, and the second side 22g of the positive electrode 21 in a stacked state. That is, the separator member 28 includes a protruding portion 30 that is a portion protruding from each side of the positive electrode 21.

  The electrode storage separator 27 includes a first welded portion 39a as a first joint portion formed by thermally welding the protruding portions 30 facing each other, and a second welded portion 39b as a second joint portion. The third welded portion 39c as a third joined portion and the fourth welded portion 39d as a fourth joined portion are provided.

  The first welded portion 39 a is a welded portion along the first side 22 f of the positive electrode 21, and is formed with a constant width along the entire first side 27 f of the electrode storage separator 27. The second welded portion 39 b is a welded portion along the second side 22 g of the positive electrode 21, and is formed with a constant width along the entire second side 27 g of the electrode storage separator 27.

  The third welded portion 39 c is a welded portion along the first side 22 c of the positive electrode 21, and is formed with a constant width along the portion of the first side 27 c of the electrode storage separator 27 excluding the positive electrode tab 31. Has been. The fourth welded portion 39 d is a welded portion along the second side 22 e of the positive electrode 21, and is formed with a constant width along the entire second side 27 e of the electrode storage separator 27.

  As shown in FIGS. 3A and 4A, the entire edge of the positive electrode 21 along the first side 22f is in contact with the inner end of the first welded portion 39a. There is almost no clearance between the edge along the one side 22f and the inner end of the first welded portion 39a. On the other hand, in the electrode storage separator 27, the edge along the second side 22g of the positive electrode 21 is located away from the inner end of the second welded portion 39b, and the edge along the second side 22g A clearance S exists between the inner end of the second welded portion 39b.

  Further, as shown in FIG. 3A, in the electrode storage separator 27, the edge along the first side 22c of the positive electrode 21 is located away from the inner end of the third welded portion 39c, and the first A clearance S exists between the edge along the side 22c and the inner end of the third welded portion 39c. Similarly, in the electrode storage separator 27, the edge along the second side 22e of the positive electrode 21 is located away from the inner end of the fourth welded portion 39d, and the edge along the second side 22e; A clearance S exists between the inner end of the fourth welded portion 39d.

  In the clearance S along the three sides of the positive electrode 21, the distance from the edge of the three sides to the inner end of the welded portion is the same, and all the clearances S have the same size. In the electrode storage separator 27, only the edge along the first side 22f of the positive electrode 21 is in contact with the inner end of the first welded portion 39a, and the other edges along the other three sides are opposite welded portions. Are stored in the storage portion 27a with a certain clearance S between them.

  As shown in FIG. 5A, the clearance S formed in the electrode storage separator 27 is welded between the opposing separator members 28 with the welding tools 61, 62, 63 and welded. , 63 are clearances that are secured in order to weld only the separator member 28 without sandwiching the positive electrode 21. This is because the positions where the welding tools 61, 62, 63 contact the separator member 28 are determined mechanically constant, but a positional shift or the like occurs when the positive electrode 21 is arranged. This is because the welding tool 61, 62, 63 is arranged at a certain distance from the position where the welding tool 61, 62, 63 contacts the separator member 28.

  3A and 4A show the electrode storage separator 27 of the present embodiment in which the edge along the first side 22f is in contact with the inner end of the first welded portion 39a. On the other hand, FIG. 3B and FIG. 4B show an electrode storage separator 70 of a comparative example. The electrode storage separator 70 of the comparative example secures a certain clearance S between the first side 71f of the positive electrode 71 and the inner end of the first welded portion 39a, and also has other three sides facing each other. A certain clearance S is ensured between the two parts. That is, in the electrode storage separator 70 of the comparative example, all four sides of the positive electrode 71 are surrounded by the clearance S.

  The electrode storage separator 27 of the present embodiment and the electrode storage separator 70 of the comparative example use the same size separator member 28, respectively, except for the first side 22 f and 71 f on the same plane of the separator member 28. It arrange | positions in the state which ensured the clearance S in the position. In this case, in the electrode storage separator 27 of the present embodiment, the length of the positive electrode 21 is such that there is no clearance S between the edge along the first side 22f and the inner end of the first welded portion 39a. The length L1 of the side can be extended in the long side direction. For this reason, compared with the long side length L2 of the positive electrode 71 accommodated in the electrode storage separator 70 of the comparative example, the long side length L1 of the positive electrode of the present embodiment can be increased. Therefore, if the length of the short side is the same in the positive electrode 21 of the embodiment and the positive electrode 71 of the comparative example, the external size of the positive electrode 21 of the embodiment is larger than the positive electrode 71 of the comparative example.

Next, a method for manufacturing the electrode storage separator 27 will be described.
As shown in FIG. 5A, the manufacturing facility 50 for the electrode storage separator 27 includes a pair of conveying rollers 51 facing each other. The pair of transport rollers 51 changes the direction of the separator member 28 so that the separator member 28 transported in the horizontal direction along each transport roller 51 is transported downward. The pair of transport rollers 51 can approach or separate from each other along the horizontal direction, and the pair of transport rollers 51 allows the separator members 28 transported downward to approach or separate from each other.

  The manufacturing facility 50 includes a pressing roller 52 disposed on the lower side in the vertical direction than the transport roller 51. The pair of pressing rollers 52 can approach or separate from each other along the horizontal direction, and the pair of pressing rollers 52 approach each other to bring the separator members 28 conveyed downward toward each other.

  The manufacturing facility 50 includes a first welding tool 61 disposed on the lower side in the vertical direction than the pressing roller 52. The pair of first welding tools 61 can approach or separate from each other along the horizontal direction. When the pair of welding tools 61 approach each other, the opposed separator members 28 are sandwiched, and heat is applied to heat the separator members 28 together. In the present embodiment, the first welding tool 61 forms the first welded portion 39 a in the electrode storage separator 27. As shown by a two-dot chain line in FIG. 6, the first welding tool 61 has a portion where the heat is applied over the entire short side of the separator member 28. Further, the pair of first welding tools 61 are separated from each other by separating the separator members 28 from each other and forming the first welded portion 39a.

  As shown in FIG. 5A, the manufacturing facility 50 includes a second welding tool 62 disposed on the upper side in the vertical direction than the first welding tool 61 and on the lower side in the vertical direction than the conveying roller 51. Is provided. The pair of second welding tools 62 is arranged at a position away from the first welding tool 61 by a certain distance along the vertical direction. The certain distance is a distance between the first welded portion 39a and the second welded portion 39b along the long side of the electrode storage separator 27.

  The pair of second welding tools 62 can approach or be separated from each other along the horizontal direction. When the pair of second welding tools 62 approach each other, the opposed separator members 28 are sandwiched, and heat is applied to heat the separator members 28 together. In the present embodiment, the second welding tool 62 forms the second welded portion 39 b in the electrode storage separator 27. As shown by a two-dot chain line in FIG. 6, the second welding tool 62 has a length that extends over the entire short side of the separator member 28. Further, the pair of second welding tools 62 are separated from each other, so that the second welding tool 62 is separated from each separator member 28 after the second welding portion 39b is formed.

  As shown in FIG. 5A, the manufacturing facility 50 includes a third welding tool 63 disposed on the lower side in the vertical direction than the first welding tool 61. The pair of third welding tools 63 can approach or be separated along the horizontal direction. When the pair of third welding tools 63 approach each other, the opposed separator members 28 are sandwiched, and heat is applied to heat the separator members 28 together. In the present embodiment, the third welding tool 63 forms the third and fourth welded portions 39c and 39d in the electrode storage separator 27. Further, as shown by a two-dot chain line in FIG. 6, the pair of third welding tools 63 has third and fourth welded portions 39 c and 39 d that are heated along the longitudinal direction of the separator member 28. It has a length that can form. The pair of third welding tools 63 are separated from each other, so that the third and fourth welding tools 63 are separated from the separator members 28 after the third and fourth welding portions 39c and 39d are formed.

Next, a method for manufacturing the electrode storage separator 27 using the manufacturing facility 50 will be described.
The manufacturing method of the electrode storage separator 27 includes a first bonding step, an electrode arrangement step, and a second bonding step, and preferably includes a third bonding step and a cutting step.

  First, in a state where the pair of separator members 28 is conveyed downward from the horizontal direction by the pair of conveyance rollers 51, the pair of conveyance rollers 51 are separated from each other, and the opposing surfaces of the separator member 28 are separated.

  Then, as shown in FIG. 5A, each pressing roller 52 is brought closer to each separator member 28, and the pair of pressing members 52 is brought closer to each other. Then, in the pair of separator members 28, a part of the lower side in the vertical direction approaches each other.

  Next, as shown in FIG. 5 (b), the pair of first welding tools 61 are brought close to the separator members 28, and the pair of separator members 28 are moved partly vertically below the pressing roller 52. Sandwich. Then, a pair of separator members 28 are heat-welded, and the 1st welding part 39a is formed over the whole short side direction of the separator member 28. FIG. And the 1st welding part 39a is formed in a part of vertical direction lower side in a pair of separator member 28, and a 1st joining process is completed. When the first joining step is completed, the pair of separator members 28 increases the interval between the opposing surfaces above the first welded portion 39a in the vertical direction.

  Next, as shown in FIG. 5C, in the separator member 28 that is spaced by the conveying roller 51, the positive electrode 21 is interposed between the separator members 28 on the upper side in the vertical direction from the first welding portion 39 a. Drop. At this time, the positive electrode 21 is dropped so that the first side 22 f of the positive electrode 21 is on the lower side in the gravity direction and the long side of the positive electrode 21 is along the vertical direction. Then, the positive electrode 21 falls due to its own weight, and the edge along the first side 22 f that is the lower side in the vertical direction of the positive electrode 21 contacts the inner end of the first welded portion 39 a. As a result, the electrode placement process is completed.

  Next, as shown in FIG. 5D, the transport rollers 51 are brought close to the separator members 28, and the pair of separator members 28 are moved closer by the pair of transport rollers 51. Then, the pair of separator members 28 comes close to the positive electrode 21 supported on the first welded portion 39 a, and the positive electrode 21 is sandwiched between the pair of separator members 28. At this time, the pair of transport rollers 51 is positioned above the second side 22g of the positive electrode 21, and the separator member 28 that is not welded between the transport rollers 51 and the second side 22g. Existing.

  And as shown in FIG.5 (e), a pair of 2nd welding tool 62 is made to approach each separator member 28, a perpendicular direction lower side than the conveyance roller 51 in a separator member 28, and a 2nd side edge The portion located vertically above 22 g is sandwiched by the second welding tool 62. At this time, the second welding tool 62 sandwiches the separator member 28 at a position with a clearance S from the edge along the second side 22g. This is to prevent the second welding tool 62 from pinching the edge along the second side 22g. Therefore, the second welding tool 62 is positioned above the first welding portion 39a in the vertical direction and joins the separator members 28 at a portion along the opposite side of the first side 22f.

  Then, the pair of separator members 28 are thermally welded to form the second welded portion 39b over the entire short side direction of the separator member 28, and the second joining step is completed. Therefore, the positive electrode 21 is closed on the outside of the first side 22f and the outside of the second side 22g by the first weld 39a and the second weld 39b.

  Next, as shown in FIG. 5 (f), the pair of separator members 28 are conveyed downward along the vertical direction by the conveying roller 51, and are held between the first welded portion 39 a and the second welded portion 39 b. The positive electrode 21 thus moved is moved to a position facing the third welding tool 63. And a pair of 3rd welding tools 63 are made to approach each separator member 28, and in the separator member 28, the part along the 1st edge | side 22c and the 2nd edge | side 22e of the positive electrode 21 is 3rd welding tool. 63.

  At this time, the third welding tool 63 sandwiches the separator member 28 at a position with a clearance S from the edge along the first side 22 c and the second side 22 e of the positive electrode 21. This is to prevent the third welding tool 63 from pinching the edges along the first side 22c and the second side 22e.

  Then, the pair of separator members 28 are thermally welded, the third welded portion 39c is formed along the first side 22c of the positive electrode 21, and the fourth welded portion 39d is formed along the second side 22e. It is formed. As a result, the third bonding step is completed, and the positive electrode 21 is closed around the four sides along the outer shape of the positive electrode 21 by the first to fourth welded portions 39a to 39d, and the pair of separator members 28 are formed in a bag shape. To be molded.

  Thereafter, as shown by a two-dot chain line in FIG. 6, in the pair of separator members 28, a portion outside the first welded portion 39 a and a portion outside the second welded portion 39 b are sandwiched by the cutting device 54. The cutting process is performed while cutting. As a result, a portion including the first to fourth welded portions 39a to 39d and the storage portion 27a that stores the positive electrode 21 is cut out from the separator member 28, and the electrode storage separator 27 is manufactured.

According to the above embodiment, the following effects can be obtained.
(1) In manufacture of the electrode storage separator 27, after forming the 1st welding part 39a in the separator member 28 conveyed toward the downward direction of a perpendicular direction, the positive electrode 21 is provided between the separator members 28 which expanded the space | interval. Was dropped. For this reason, when the positive electrode 21 is disposed between the pair of separator members 28, the positive electrode 21 is less likely to be in sliding contact with the separator member 28, and the active material layer 23 is not easily damaged due to the positive electrode active material layer 23 being rubbed.

  (2) In the manufacture of the electrode storage separator 27, the positive electrode 21 is dropped between the separator members 28 having a wide interval, and the edge along the first side 22f is abutted against the inner end of the first welded portion 39a. The clearance S between them was eliminated. For this reason, compared with the case where the clearance S exists between all the four sides of the positive electrode 21 and the facing joint, the outer size of the positive electrode 21 can be increased by the amount of the clearance S being lost. it can. As a result, in the secondary battery 10, the area of the positive electrode active material layer 23 facing the negative electrode active material layer 26 can be increased, and the energy density of the secondary battery 10 can be increased.

  (3) The pair of separator members 28 are welded by the first to fourth welded portions 39a to 39d so as to surround the four sides of the positive electrode 21, and then the pair of separator members 28 are cut by the cutting process to form electrodes. The storage separator 27 was obtained. For this reason, the electrode storage separator 27 can be manufactured one by one.

  (4) After a pair of separator members 28 are welded to each other and the first welded portion 39a supports the edge along the first side 22f, a clearance S is provided between the remaining three sides and the welded portion. The 2nd-4th welding part 39b-39d was formed so that it could do. For this reason, the positive electrode 21 is not sandwiched between the first to third welding tools 61 to 63.

  (5) In general, in a method in which an electrode is sandwiched in advance between a pair of separator members and a welding part is formed with a welding tool, many of the causes of the problem that the electrode is sandwiched between welding tools are Misalignment. In the present embodiment, the first welded portion 39a is formed in advance, and after positioning the edge along the first side 22f of the positive electrode 21 by the first welded portion 39a, the remaining three sides 2nd-4th welding parts 39b-39d are formed along. Therefore, it is possible to reduce the clearance and increase the outer size of the positive electrode 21 while reducing the possibility that the positive electrode 21 is sandwiched by the welding tool.

In addition, you may change the said embodiment as follows.
As shown in FIG. 7, the separator member 28 is conveyed in the vertical direction with the longitudinal direction thereof being oblique with respect to the vertical direction, and in the first joining step, the first side 22 f of the positive electrode 21, You may form the L-shaped 1st welding part 39f along two sides with the 2nd edge | side 22e as a 1st junction part.

  In this case, in the first joining step, the first welded portion 39f is formed in an L shape that intersects the longitudinal direction of the separator member 28 along the short direction. When configured in this way, when the positive electrode 21 is dropped in the electrode placement step, the edge along the first side 22f and the edge along the second side 22e of the positive electrode 21 are L-shaped first welds. It contacts the inner end of the portion 39f. Therefore, in the first joining step, the second side 22e, which is one side of the positive electrode 21 along the longitudinal direction of the separator member 28, intersects the second side 22e and extends in the short direction of the separator member 28. A first welded portion 39f is formed along the first side 22f, which is another side.

  As a result, the positive electrode 21 is supported by the first welded portion 39f at two sides positioned on the lower side in the vertical direction. In other words, the positive electrode 21 receives the corner where the second side 22e and the first side 22f intersect by the L-shaped corner of the first welded portion 39f, thereby restricting the displacement of the positive electrode 21. can do. As a result, when forming the welded portion along the remaining two sides, the positive electrode 21 is difficult to move, and the positive electrode 21 can be prevented from being sandwiched between the welding tools.

  In the embodiment, the cutting process is performed every time one electrode storage separator 27 is manufactured, but a series of manufacturing processes including a first bonding process, an electrode arrangement process, a second bonding process, and a third bonding process. After performing the steps, the above-described series of manufacturing steps may be repeated without performing the cutting step.

  In this case, as shown in FIG. 8, a plurality of electrode storage separators 27 are formed along the longitudinal direction of the separator member 28. The plurality of electrode storage separators 27 are bent from between the positive electrodes 21 adjacent to each other in the longitudinal direction of the separator member 28 to form a zigzag shape, and the negative electrode 24 is sandwiched between the electrode storage separators 27 to form an electrode assembly. Can be formed.

  In the embodiment, after the second bonding step, the third bonding step is performed to form the first to fourth welded portions 39a to 39d and the electrode storage separator 27, but this is not restrictive. For example, in the second bonding step, the second to fourth welded portions 39b to 39d other than the first welded portion 39a may be formed in a lump. In this case, the third joining step is omitted. Therefore, after forming the first welded portion by the first joining step, the order of forming the other welded portions may be appropriately changed as long as the second welded portion is formed along the opposite side.

  In the embodiment, in the electrode arrangement step, the positive electrode 21 is dropped so that the long side direction of the positive electrode 21 is along the vertical direction, but the short side direction of the positive electrode 21 is along the vertical direction, and the second side 22e is The positive electrode 21 may be dropped so as to be positioned at the lower end in the vertical direction. In this case, it is preferable that the positive electrode tab 31 protrudes from the long side of the positive electrode 21.

  In the embodiment, in the electrode placement step, the positive electrode 21 is dropped so that the first side 22f of the positive electrode 21 is located at the lower end in the vertical direction, but conversely, the second side 22g of the positive electrode 21 The positive electrode 21 may be dropped so that is positioned at the lower end in the vertical direction.

  ○ The method of forming the joint portion where the pair of separator members 28 are joined is embodied by welding. However, the method is suitable for adhesion for forming the adhesive portion as the joint portion and fusion for forming the fusion portion as the joint portion. It may be changed.

In the embodiment, the welded portion is formed along the entire side of the positive electrode 21, but the welded portion may be formed in spots along the side of the positive electrode 21.
The electrode storage separator 27 may be one that encloses the negative electrode 24.

The positive electrode 21 may have the positive electrode active material layer 23 only on one side.
The negative electrode 24 may have the negative electrode active material layer 26 only on one side.
The secondary battery 10 is a lithium ion secondary battery, but is not limited thereto, and may be another secondary battery. In short, any material may be used as long as ions move between the positive electrode active material and the negative electrode active material and transfer charge.

-It may be embodied in a power storage device such as an electric double layer capacitor.
Next, the technical idea that can be grasped from the above embodiment and other examples will be described below.
(A) A power storage device including an electrode assembly in which a positive electrode and a negative electrode are stacked in a state in which the positive electrode and the negative electrode are insulated by a separator, and one of the positive electrode and the negative electrode is wrapped with a separator. 5. An electrical storage device comprising an electrode storage separator, wherein the electrode storage separator is the electrode storage separator according to claim 1.

  21... Positive electrode as electrode, 22 c. First side as one side of electrode, 22 f. First side as a lower side in the vertical direction, 22 g... Second side as an opposite side and another side. , 27... Electrode storage separator, 28... Separator member, 30... Protruded portion, 39 a... First welding portion as the first joining portion, 39 b... Second welding as the second joining portion 39c, a third welded portion as the joint portion, 39d, a fourth welded portion as the joint portion, 39f, a first welded portion as the first joint portion.

Claims (5)

A rectangular sheet-like electrode is housed between separator members facing each other, and the separator housing member is a method for producing an electrode housing separator having a joined portion that joins portions protruding from the sides of the electrode,
Facing each other and sandwiching the elongated pair of separators portion material conveyed vertically downward while being spaced apart opposing faces arranged pair of pressing rollers, each other said pair of pressing rollers The opposing surfaces of the separator members are brought closer to each other by bringing them closer together, and the approached separator members are joined at a part vertically below the pressing roller, and the first joining along the side of the electrode A first joining step for forming a portion;
After the pair of pressing rollers are separated from each other, the gap between the opposing surfaces of the pair of separator members is widened in the vertical direction above the first joint portion, and then, in the vertical direction above the first joint portion. An electrode placement step in which the electrode is dropped between the opposing surfaces of the separator member, and an edge along the lower side in the vertical direction of the electrode is brought into contact with the inner end of the first joint portion;
A second joining step that is located vertically above the first joint and that joins the separator members at least along the opposite side of the side of the electrode to form a second joint. The manufacturing method of the electrode storage separator containing. A pair of transport rollers for transporting the pair of separator members are arranged vertically above the pressing roller;
The pair of transport rollers are separated from each other during the period from the start of the first joining step to the completion of the electrode placement step, thereby separating the opposing surfaces of the separator member from each other, and the second The opposing surfaces of the separator members are brought closer to each other by approaching each other at the start of the joining process,
The manufacturing method of the electrode storage separator of Claim 1 which forms a said 2nd junction part in the perpendicular direction lower side rather than the said conveyance roller in the separator members made to approach in the said 2nd joining process. The method for manufacturing an electrode storage separator according to claim 1, wherein the electrode is a positive electrode. The cutting process which cut | disconnects a pair of said separator member, after joining the said separator members in the part in alignment with the remaining edge | side of the said electrode, and forming a junction part . method of producing an electrode housing separator according to one paragraph. The pair of separator members extend in the vertical direction in a state where the longitudinal direction is oblique to the vertical direction, and in the first joining step, one side of the electrode along the longitudinal direction of the separator member intersects the one side, In addition, the first joint portion is formed along another side extending in the short direction of the separator member. In the electrode placement step, the electrode is dropped and dropped in a state where the longitudinal direction is oblique to the vertical direction. The one side of the electrode along the longitudinal direction of the separator member that becomes the lower side of the electrode in the vertical direction, and another side of the electrode that intersects the one side and extends in the short direction of the separator member The manufacturing method of the electrode storage separator as described in any one of Claims 1-4 which makes the edge of this electrode along these contact | abut to the inner edge end of a said 1st junction part .