Electricity storage device and method for manufacturing the electricity storage device

Abstract

An electricity storage device (1, 101, 201) in which a plurality of electrodes (10, 212), in which a positive electrode layer (13) is provided on one surface of a collector plate (11) and a negative electrode layer (15) is provided on the other surface of the collector plate (11), are stacked via separators (17, 220), the electricity storage device (1, 101, 201) comprising: a plurality of spacers (21, 121) arranged along peripheral edges of the collector plates (11) between the collector plates (11) adjacent to one another in a stacking direction; and a resin frame (25, 125) covering outer peripheries of the plurality of spacers (21, 121) when viewed from the stacking direction, wherein the spacer (21, 121) has a first portion (241) overlapping with the resin frame (25, 125) when viewed from the stacking direction and a second portion (242) extending inward from the resin frame (25, 125) when viewed from the stacking direction, wherein the first portion (241) is bonded to the resin frame (25, 125), wherein the second portion (242) is bonded to the collector plate (11), wherein the resin frame (25, 125) is formed by injection molding, wherein an outer periphery (21b, 121b) of the spacer (21, 121) and an inner peripheral surface of the resin frame (25, 125) are integrated by welding, and wherein the resin frame (25, 125) collectively covers the outer peripheries of the plurality of spacers (21, 121).

Description

Technical field

[0001] The present invention relates to an electricity storage device and a method for manufacturing the electricity storage device. State of the art

[0002] In the prior art, an electricity storage device having a bipolar electrode is known. For example, a battery disclosed in JP 2010-212092 A includes a plurality of electrodes in which a positive electrode layer electrically coupled to one surface of a collector is formed, and a negative electrode layer electrically coupled to a surface on the opposite side of the collector is formed. These electrodes are stacked over an electrolyte layer constituting an electricity-generating element. For the purpose of preventing fluid communication due to leakage of the electrolytic solution from the electrolyte layer, a sealing portion is disposed on the outer peripheral portion of the battery.

[0003] US 2004 / 0 253 512 A1 discloses a bipolar battery. It comprises a bipolar electrode and an electrolyte layer. The bipolar electrode includes a current collector, a positive electrode layer formed on one surface of the current collector, and a negative electrode layer formed on the other surface of the current collector. The bipolar electrode is sequentially laminated to provide a series connection across the electrolyte layer to form a stacked structure. The positive electrode layer, the negative electrode layer, and the electrolyte layer are encapsulated with a resin portion.

[0004] US 2006 / 0 292 443 A1 discloses a bipolar battery. It has a positive electrode unit, a negative electrode unit, at least one bipolar electrode unit stacked therebetween, an electrolyte layer separating each adjacent electrode unit, and a gasket positioned around each electrolyte layer for sealing the electrolyte layer in conjunction with the adjacent electrode units. The bipolar battery also includes a shell for maintaining the seal created by the gaskets.

[0005] JP 2005-259379 A discloses a bipolar battery having a battery element 21 with bipolar electrodes 11 stacked therein, each bipolar electrode 11 being formed by forming a positive electrode layer 15 on one side of a collector 13 and a negative electrode layer 17 on the other side thereof. The battery includes bipolar electrode frame complexes in which each peripheral edge constituting the respective bipolar electrodes 11 is held by two frames 1a, 1b, respectively, and each of the frames of the bipolar frame complexes adjacent to each other in the stacking direction of the battery element is connected in the stacking direction of the battery element to form a frame stack.

[0006] DE 603 ​​02 634 T2 discloses a bipolar battery and insulation. JP 2001-155 973 A discloses an electrochemical capacitor according to the prior art. Summary of the inventionTechnical problem

[0007] Generally, in a battery having a structure in which bipolar electrodes are stacked in the stacking direction, the electrodes arranged adjacent to each other in the stacking direction may contact each other, and thus, a short circuit may occur. Therefore, in the battery disclosed in Patent Literature 1, for example, short circuits are prevented by insulating adjacent electrodes using sealing portions.

[0008] However, the sealing portion disclosed in JP 2010-212092 A is mainly intended to prevent leakage of an electrolytic solution, and the sealing portion is pressed by a predetermined amount in the stacking direction. In this case, in order to maintain the height of the stacked body to be uniform, it is necessary to strictly adjust the amount of compression of each sealing portion, and transverse shaping becomes difficult. Therefore, the accuracy requirement for the component is increased, resulting in an increase in manufacturing costs.

[0009] An object of the present invention is to provide an electricity storage device and a method for manufacturing an electricity storage device capable of suppressing a short circuit between electrodes at a low cost. Solution to the problem

[0010] According to one aspect of the disclosure, there is provided an electricity storage device in which the plurality of electrodes, in which a positive electrode layer is provided on one surface of a collector plate and a negative electrode layer is provided on the other surface of the collector plate, are stacked via separators, the electricity storage device comprising: a plurality of spacers arranged along peripheral edges of the collector plates between the collector plates adjacent to each other in a stacking direction; and a resin frame covering outer peripheries of the plurality of spacers.

[0011] In such an electricity storage device, short circuits between collector plates are suppressed by a plurality of spacers arranged between the collector plates adjacent to each other in the stacking direction. Furthermore, by covering the outer peripheries of the plurality of spacers, the peripheral edges of the stacked plurality of electrodes are formed in a liquid-tight manner, and thus, leakage of an electrolytic solution can be prevented. With such a configuration, it is unnecessary to consider the amount of compression and the like, so the accuracy requirement of each component does not increase. Therefore, it is possible to suppress short circuits between electrodes at a low cost.

[0012] Furthermore, in one aspect, the spacer and the resin frame may be formed with the same material. Furthermore, in one aspect, the spacer and the resin frame may be formed with different materials. For example, in a case where it is desired to integrate the spacer and the resin frame by welding or the like, it is desirable that the spacer and the resin frame be formed with the same material.

[0013] Furthermore, in one aspect, the outer periphery of the collector plate may be disposed within the spacer. According to such a configuration, it is possible to bond the spacer and the collector plate in a fluid-tight manner.

[0014] Furthermore, in one aspect, the outer periphery of the collector plate may be disposed within the resin frame. According to such a configuration, it is possible to more reliably connect the resin frame and the collector plate in a fluid-tight manner.

[0015] Furthermore, in one aspect, the outer periphery of the spacer may have a convex shape toward the resin frame. According to such a configuration, it is possible to further suppress contact between the collector plates adjacent to each other.

[0016] Furthermore, in one aspect, a distal end of the outer periphery of the spacer may extend to a position outside the outer periphery of the collector plate. According to such a configuration, it is possible to reliably suppress contact between the adjacent collector plates.

[0017] Furthermore, in one aspect, an inner peripheral surface of the resin frame may have a concave shape corresponding to the convex shape of the outer periphery of the spacer. According to such a configuration, the spacer and the resin frame can be easily brought into close contact with each other.

[0018] Furthermore, in one aspect, a cut line or incision continuous with the outer periphery may be formed on the peripheral edge of the collector plate. Since the peripheral edge of the collector plate can be easily moved through the incision, it is possible to suppress the occurrence of wrinkles or unevenness and the like.

[0019] Furthermore, in one aspect, the spacer has a first portion that overlaps with the resin frame when viewed from the stacking direction, and a second portion that extends inward from the resin frame when viewed from the stacking direction. The first portion may be bonded to the resin frame, and the second portion may be connected to the collector plate. Since the rigidity of the collector plate can be improved by the second portion being connected to the collector plate, it is possible to suppress deformation of the electricity storage device due to an external force such as internal pressure.

[0020] Furthermore, in one aspect, the second portion does not need to overlap with either the positive electrode layer or the negative electrode layer when viewed from the stacking direction, and the second portion may have a portion that overlaps with the separator when viewed from the stacking direction. According to such a configuration, since an area where the spacer and the separator overlap with each other can be properly secured, it is possible to effectively suppress a short circuit between the collector plates.

[0021] Furthermore, in one aspect, the spacer and the resin frame may be formed of the same material. For example, in a case where the spacer and the resin frame are integrated by welding or the like, it is desirable that the spacer and the resin frame be formed of the same material.

[0022] Furthermore, in one aspect, the spacer may be formed into a frame shape when viewed from the stacking direction. According to such a configuration, it is possible to simplify the shape of the spacer.

[0023] Furthermore, in one aspect, the electricity storage device may further include a connecting portion that connects end portions of the spacers adjacent to each other in the stacking direction. According to such a configuration, by providing the connecting portion, it is possible to suppress warping of the spacer. As a result, it is possible to effectively suppress occurrence of stacking misalignment of the plurality of electrodes. Furthermore, in one aspect, a protrusion amount of the spacer from an end surface of the collector plate facing in a direction intersecting the stacking direction may be equal to or greater than a thickness of the spacer in the stacking direction. According to such a configuration, it is possible to relax restrictions on a design method at the time of forming the resin frame.For example, it is easy to join the resin frame to the spacer by hot-plate welding using the protrusion portion (i.e., the first portion) of the spacer having a protrusion amount equal to or greater than a predetermined value, as described above.

[0024] Furthermore, in one aspect, the resin frame may be formed by injection molding. Furthermore, in one aspect, the resin frame may be formed by hot-plate welding to the spacer. According to such a configuration, it is possible to form the peripheral edges of the stacked plurality of electrodes in a liquid-tight manner through the resin frame, and accordingly, it is possible to prevent leakage of an electrolytic solution.

[0025] Furthermore, according to one aspect of the invention, there is provided a method for manufacturing an electricity storage device, comprising the processes of: fixing spacers to peripheral edges of collector plates in electrodes in which a positive electrode layer is provided on one surface of the collector plate and a negative electrode layer is provided on the other surface of the collector plate; stacking a plurality of electrodes to which the spacers are fixed; and forming a resin frame by injection molding or hot-plate welding on the spacers to cover outer peripheries of the spacers fixed to the stacked plurality of electrodes.

[0026] According to such a method of manufacturing an electricity storage device, the spacers are fixed to the peripheral edges of the collector plates, and then the electrodes are stacked such that the respective spacers are arranged between the collector plates adjacent to each other in the stacking direction. With this spacer, a short circuit between the collector plates is suppressed. Furthermore, by the resin frame collectively covering the outer peripheries of the plurality of spacers, the peripheral edges of the stacked plurality of electrodes are formed in a liquid-tight manner, and thus, leakage of an electrolytic solution is prevented. Since the resin frame is formed to the spacer by injection molding or hot-plate welding, it is possible to easily manufacture the resin frame. Therefore, it is possible to suppress the short circuit between the electrodes at a low cost.

[0027] Furthermore, in one aspect, the manufacturing method may further include a process of joining end portions of the spacers adjacent to each other in the stacking direction before the process of forming the resin frame. According to such a configuration, it is possible to form the resin frame in a state where warping of the spacers is suppressed. As a result, it is possible to suppress stacking misalignment of a plurality of electrodes. Advantageous effects of the invention

[0028] According to one aspect of the electricity storage device and the method for manufacturing the electricity storage device, it is possible to suppress a short circuit between the electrodes at a low cost. Brief description of the drawings Fig. 1 is a cross-sectional view schematically illustrating an electricity storage device according to a first embodiment. Fig. Figure 2 is a plan view schematically illustrating a bipolar electrode. Fig. 3 is a view illustrating a manufacturing process of the electricity storage device. Fig. 4 is a view illustrating a manufacturing process of the electricity storage device. Fig. 5 is a cross-sectional view schematically illustrating an electricity storage device according to a second embodiment. Fig. 6. is a cross-sectional view schematically illustrating an electricity storage device according to a third embodiment. Fig. 7 is a cross-sectional view showing an electricity storage module incorporating the electricity storage device of Fig. 6, schematically represents. Fig. 8 is a cross-sectional view taken along a line VIII-VIII of Fig. 7 is taken. Fig. 9 is a view illustrating hot element welding of a second sealing portion to a first sealing portion. Fig. 10 is a view schematically showing an example of a connecting portion. Description of embodiments

[0029] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. For simplicity, substantially the same elements are denoted by the same reference numerals, and their descriptions may be omitted. [First embodiment]

[0030] Fig. 1 is a cross-sectional view schematically illustrating a configuration of an electric storage device according to an embodiment of the present invention. Fig. Fig. 2 is a plan view schematically illustrating a bipolar electrode used in the electricity storage device. An electricity storage device 1 used in Fig. 1 is, for example, a secondary battery such as a nickel-hydrogen secondary battery or a lithium-ion secondary battery, or an electric double-layer capacitor. The electricity storage device 1 is used as a battery of various vehicles, such as a forklift, a hybrid vehicle, and an electric vehicle. In the following description, a nickel-hydrogen secondary battery is illustrated.

[0031] As in Fig. As shown in Figure 1, the electricity storage device 1 includes a plurality of bipolar electrodes 10, a frame 20, and a pair of restricting plates 30A and 30B. The bipolar electrode 10 includes a collector plate 11, a positive electrode layer 13 provided on one surface 11a of the collector plate 11, and a negative electrode layer 15 provided on the other surface 11b (surface opposite to the one surface 11a of the collector plate 11) of the collector plate 11. The collector plate 11 is a metal foil made of nickel, for example, and has a rectangular shape in a plan view, as shown in Fig. 2. The thickness of the collector plate 11 is, for example, approximately 0.1 µm to 1000 µm. As the positive electrode active material constituting the positive electrode layer 13, nickel hydroxide and the like can be exemplified. As the negative electrode active material constituting the negative electrode layer 15, a hydrogen storage alloy and the like can be exemplified.

[0032] As in Fig. 2, a peripheral edge 11c of the collector plate 11 is an uncoated area that is not coated with the positive electrode active material and the negative electrode active material. The formation area of ​​the negative electrode layer 15 on the other surface 11b of the collector plate 11 may be slightly larger than the formation area of ​​the positive electrode layer 13 on the one surface 11a of the collector plate 11. On the peripheral edge 11c of the collector plate 11, notches 11e are formed continuously from an outer periphery 11d. In this embodiment, the notches 11e are formed at the four corners of the collector plate 11. The notch 11e is formed from the vertex of the corner to the position within the uncoated area and does not reach the negative electrode layer 15.

[0033] The plurality of bipolar electrodes 10 are stacked via separators 17. In a state where the plurality of bipolar electrodes are stacked, the positive electrode layer 13 of one bipolar electrode 10 faces the negative electrode layer 15 of one bipolar electrode 10 adjacent in the stacking direction with the separator 17 interposed therebetween, and the negative electrode layer 15 of one bipolar electrode 10 faces the positive electrode layer 13 of the other bipolar electrode 10 adjacent in the stacking direction with the separator 17 interposed therebetween. In this embodiment, the negative electrode layer 15 provided on the other surface 11b of each bipolar electrode 10 is covered with the sheet-shaped separator 17.Therefore, by stacking the plurality of bipolar electrodes 10 in the same direction with respect to the stacking direction, the separator 17 is arranged between the positive electrode layer 13 and the negative electrode layer 15 of the adjacent bipolar electrodes 10.

[0034] As a material constituting the separator 17, a porous film made of a polyolefin resin such as polyethylene (PE) or polypropylene (PP), a woven or nonwoven fabric made of polypropylene, polyethylene terephthalate (PET), methylcellulose, or the like, etc., are exemplified. Furthermore, the separator 17 may be reinforced with a vinylidene fluoride resin compound.

[0035] A collector plate 18 provided with only the positive electrode layer 13 is placed on a surface of one stacked end (stacked end on the upper side in Fig. 1) of the stacked bipolar electrodes 10. The positive electrode layer 13 of the collector plate 18 faces the negative electrode layer 15 of the bipolar electrode 10 as the uppermost layer across the separator 17. In addition, a collector plate 19 provided with only the negative electrode layer 15 is stacked on the other stacked end (stacked end on the lower side in Fig. 1) of the stacked bipolar electrodes 10. The negative electrode layer 15 is covered with the separator 17. The negative electrode layer 15 of the collector plate 19 faces the positive electrode layer 13 of the bipolar electrode 10 as the lowermost layer across the separator 17. Similar to the collector plate 17, the collector plates 18 and 19 are metal foils made of, for example, nickel and have a rectangular shape in a plan view.

[0036] The peripheral edge 11c of the collector plate 11 is held by the frame 20 in a state where it is embedded in the inner wall of the frame 20. Therefore, a space partitioned by the collector plates 11 and 11 and the inner wall of the frame 20 is formed between the collector plates 11 and 11 adjacent to each other in the stacking direction. This space contains an electrolytic solution (not shown) made of an alkaline solution such as an aqueous potassium hydroxide solution.

[0037] Similar to the collector plate 11 of the bipolar electrode 10, peripheral edges 18c and 19c of the collector plates 18 and 19 are held by the frame 20 in a state where they are embedded in the inner wall of the frame 20. Furthermore, the collector plates 18 and 19 may be formed to be thicker than the collector plate 11 of the bipolar electrode 10.

[0038] The frame 20 is formed by a plurality of spacers 21 and a resin frame 25 and has a rectangular tubular shape. In this embodiment, the inner wall of the frame 20 is formed by the plurality of spacers 21, and the outer wall of the frame 20 is formed by the resin frame 25.

[0039] The spacer 21 is formed with an insulating resin and has a rectangular frame shape. An inner periphery 21a of the spacer 21 is located inside the outer periphery 11d of the collector plate 11 of the bipolar electrode 10, and an outer periphery 21b of the spacer 21 is located outside the outer periphery 11d of the collector plate 11. The spacer 21 has a predetermined thickness in the stacking direction of the bipolar electrodes 10. The thickness of the spacer 21 is substantially equal to a sum of the thickness of the bipolar electrode 10 and the thickness of the separator, and is, for example, 0.1 to 0.5 mm. The spacer 21 holds the peripheral edge 11c of the collector plate 11 of the bipolar electrode 10. That is, the outer periphery 11d of the collector plate 11 is disposed within the spacer 21. In this embodiment, the peripheral edge 11c of the collector plate 11 is arranged at the center of the spacer 21 in the thickness direction.For example, the peripheral edge 11c of the collector plate 11 and the spacer 21 are bonded by thermocompression bonding or the like. In a state where the plurality of bipolar electrodes 10 are stacked, the plurality of spacers 21 are also stacked. In this state, a portion (the portion facing the other bipolar electrode side) of the spacer 21 that holds one bipolar electrode 10 and a portion (the portion facing one bipolar electrode side) of the spacer 21 that holds the other bipolar electrode 10 are arranged between the bipolar electrodes 10 and 10 adjacent to each other in the stacking direction.

[0040] Similar to the collector plate 11 of the bipolar electrode 10, the peripheral edges 18c and 19c of the collector plates 18 and 19 are held by the spacer 21. A portion of the spacer 21 holding the collector plate 18 and a portion of the spacer 21 holding the collector plate 11 are disposed between the collector plate 18 and the collector plate 11 adjacent to the collector plate 18. A portion of the spacer 21 holding the collector plate 19 and a portion of the spacer 21 holding the bipolar electrode 10 are disposed between the collector plate 19 and the collector plate 11 adjacent to the collector plate 19.

[0041] The resin frame 25 has a rectangular tubular shape and collectively covers the outer peripheries of the plurality of spacers 21. The plurality of spacers 21 and the resin frame 25 are integrated by welding or the like, for example. The resin constituting the resin frame 25 may be the same as the resin constituting the spacer 21. As such a resin, polypropylene (PP), polyphenylene sulfide (PPS), modified polyvinyl ether (modified PPE), and the like can be exemplified.

[0042] The pair of restriction plates 30A and 30B restrict the plurality of bipolar electrodes 10 and the collector plates 18 and 19 in the stacking direction. In addition, the pair of restriction plates 30A and 30B also restricts the frame 20. A positive electrode terminal 33 is connected to one restriction plate 30A. A negative electrode terminal 35 is connected to the other restriction plate 30B. It is possible to perform charging and discharging of the electricity storage device 1 through the positive electrode terminal 33 and the negative electrode terminal 35.

[0043] The restriction plates 30A and 30B are provided with through holes 37 for penetrating bolts 36 extending in the stacking direction. The bolt 36 is inserted from the restriction plate 30A toward the restriction plate 30B. A nut 38 is screwed onto the distal end of the bolt 36. Therefore, the restriction plates 30A and 30B apply a restriction load to the plurality of bipolar electrodes 10 including the separator 17, the collector plate 18, the collector plate 19, and the frame 20. As a result, the interior of the frame 20 is sealed.

[0044] Hereinafter, a method for manufacturing the above-described electricity storage device 1 will be described.

[0045] The method of manufacturing the electricity storage device 1 according to this embodiment includes a first process of fixing the spacers 21 to the peripheral edges 11c of the collector plates 11 in the bipolar electrodes 10, a second process of stacking the plurality of bipolar electrodes 10 to which the spacers 21 are fixed, and a third process of forming the resin frame 25 on the outer sides of the spacers 21 fixed to the stacked bipolar electrodes 10.

[0046] Fig. 3 is a view illustrating the first process. In the first process, the separator 17 is fixed to the bipolar electrode 10 with the collector plate 11, the positive electrode layer 13, and the negative electrode layer 15. Then, the spacer 21 is fixed to the peripheral edge 11c of the collector plate 11 in the bipolar electrode 10. As shown in a section (a) of Fig. 3, in this embodiment, a half spacer piece 22 having a rectangular frame shape in which the spacer 21 is divided in the thickness direction is provided. An inner periphery 22a of the half spacer piece 22 is located inside the outer periphery 11d of the collector plate 11 of the bipolar electrode 10, and an outer periphery 22b of the half spacer piece 22 is located outside the outer periphery 11d of the collector plate 11. The half spacer pieces 22 are arranged on one surface 11a and the other surface 11b of the collector plate 11 of the bipolar electrode 10, respectively. The peripheral edge 11c of the collector plate 11 is located between the pair of half spacer pieces 22 and 22. Then, as shown in a section (b) of Fig. 3, by applying pressure to the pair of half spacer pieces 22 and 22 while heating them, the collector plate 11 and the pair of half spacer pieces 22 and 22 are thermocompression bonded, and the pair of half spacer pieces 22 and 22 are thermocompression bonded to each other. Therefore, the bipolar electrode 10 is held by the spacer 21.

[0047] Fig. 4 is a view illustrating the second process and the third process. Subsequently, by the second process, the plurality of bipolar electrodes 10 to which the spacers 21 are fixed are stacked. In the second process, a predetermined number of the bipolar electrodes 10 to which the spacers 21 are fixed by the first process are stacked. In this case, the bipolar electrodes 10 are stacked such that the directions of the positive electrode layer 13 and the negative electrode layer 15 of all the bipolar electrodes 10 are the same. A collector plate 18 is arranged at the end portion of the stacked bipolar electrode 10 on the negative electrode layer 15 side. Furthermore, a collector plate 19 is arranged at the end portion of the stacked bipolar electrode 10 on the positive electrode layer 13 side.Similar to the bipolar electrodes 10, the spacers 21 are fixed to the peripheral edges 18c and 19c of the collector plates 18 and 19.

[0048] In the subsequent third process, a resin frame 25 is formed on the outside of the plurality of spacers 21, which holds the plurality of bipolar electrodes 10 and the collector plates 18 and 19 that are stacked. In the third process, the resin frame 25 is formed by injection molding. As shown in Fig. 4, a mold K is fixed to the outer peripheries of the stacked spacers 21, and a resin is injected into the mold K. In this embodiment, the outer peripheries 21b of the spacers 21 are exposed inside the mold K. For this reason, the resin injected into the mold K and the outer peripheries 21b of the spacers 21 are welded and integrated. Therefore, the resin frame 25 is formed, which collectively covers the outer peripheries 21b of all the spacers 21. That is, the frame 20 is formed by the spacers 21 and the resin frame 25. Then, the electric storage device 1 is formed by constraining the plurality of bipolar electrodes 10 with the separators 17, the collector plate 18, the collector plate 19 and the frame 20 using the pair of constraining plates 30A and 30B.

[0049] In the electricity storage device 1 described above, the collector plates 11 are prevented from coming into direct contact with each other by the plurality of spacers 21 arranged between the collector plates 11 adjacent to each other in the stacking direction, and thus short circuiting is prevented. Furthermore, the outer peripheries 11d of the stacked plurality of collector plates 11 are formed in a liquid-tight manner by the resin frame 25 collectively covering the outer peripheries 21b of the plurality of spacers 21, and thus leakage of an electrolytic solution is prevented. In the prior art, it is necessary to strictly adjust the amount of compression of the sealing portion that insulates between the adjacent electrodes.However, in the configuration described above, since it is not necessary to consider the amount of compression or the like, the accuracy requirement of each component is not increased. Therefore, it is possible to suppress the short circuit between the electrodes at low cost.

[0050] Furthermore, according to the method for manufacturing the electricity storage device 1 described above, the spacers 21 are fixed to the peripheral edges 11c of the collector plates 11, and then the bipolar electrodes 10 are stacked. As a result, the spacers 21 are arranged between the collector plates 11 adjacent to each other in the stacking direction. For example, when injection molding is performed to form the resin frame 25 in a state where the spacers 21 are not arranged, there is a concern that the peripheral edges 11c of the adjacent collector plates 11 are moved by the injected resin. In this case, there is a concern that the moved peripheral edges 11c are in contact with each other. Furthermore, there is a concern that the injected resin may flow and reach the positive electrode layer 13 or the negative electrode layer 15.In this embodiment, by disposing the spacers 21 in advance before resin injection, contact between the collector plates 11 is suppressed. Furthermore, the spacers 21 prevent the resin from penetrating toward the positive electrode layer 13 side and the negative electrode layer 15 side. Furthermore, since the resin frame 25 is formed by injection molding, the resin frame 25 can be easily manufactured. Therefore, it is possible to suppress a short circuit between the electrodes at low cost.

[0051] Furthermore, since the spacer 21 and the resin frame 25 are formed of the same material, in the process of forming the resin frame 25 by injection molding, the spacer 21 and the resin frame 25 are integrated by welding. Therefore, it is possible to more effectively suppress electrolytic solution leakage.

[0052] Furthermore, the outer periphery 11d of the collector plate 11 is disposed in the spacer 21. According to such a configuration, it is possible to bond the spacer 21 and the collector plate 11 in a liquid-tight manner.

[0053] Furthermore, cuts 11e continuous with the outer periphery 11d are formed on the peripheral edge 11c of the collector plate 11. In the embodiment, the cuts 11e are formed at four corners of the collector plate 11 in a rectangular shape. Therefore, the peripheral edge 11c of the collector plate 11 is divided into four sections corresponding to the sides, and the four sections move independently of each other. Therefore, occurrence of wrinkles, twists, or the like on the collector plate 11 at the time of attaching the spacer 21 or the like is suppressed. [Second embodiment]

[0054] An electricity storage device according to this embodiment is mainly different from the electricity storage device 1 according to the first embodiment in terms of the shape of the spacer. Hereinafter, differences from the first embodiment will be mainly described, and the same elements and components are denoted by the same reference numerals, and a detailed description thereof will be omitted.

[0055] Fig. 5 is a cross-sectional view schematically illustrating the electricity storage device according to this embodiment. As in Fig. 5, an electricity storage device 101 includes a plurality of bipolar electrodes 10, a frame 120, and a pair of restricting plates 30A and 30B.

[0056] The frame 120 is formed by a plurality of spacers 121 and a resin frame 125 and has a rectangular tubular shape. The spacer 121 is formed with an insulating resin and has a rectangular frame shape. The spacer 121 has a predetermined thickness in the stacking direction of the bipolar electrode 10. Similar to the first embodiment, the thickness of the spacer 121 is substantially equal to the thickness of the bipolar electrode 10. The center of the outer periphery 121b of the spacer 121 in the thickness direction has a convex shape toward the resin frame 125. In the illustrated example, the outer periphery 121b of the spacer 121 is inclined to protrude toward the resin frame 125 side at the center in the thickness direction. The distal end of the outer periphery 121b of the spacer 121 extends to a position outside the outer periphery 11d of the collector plate 11.

[0057] The spacer 121 is arranged between the bipolar electrodes 10 adjacent to each other in the stacking direction. Furthermore, the spacer 121 is arranged on the peripheral edge 11c of the collector plate 11 of the bipolar electrode 10. That is, the peripheral edge 11c of the collector plate 11 is located between a pair of spacers 121 and 121 arranged on one side and the other side in the stacking direction. Furthermore, as shown in the drawing, the outer periphery 11d of the collector plate 11 is not located between the spacers 121 but extends to the resin frame 125 side. Furthermore, the spacers 121 are also arranged between the collector plate 18 and the bipolar electrode 10, and between the collector plate 19 and the bipolar electrode 10.

[0058] The resin frame 125 has a rectangular tubular shape and collectively covers the outer peripheries 121b of the plurality of spacers 121. The plurality of spacers 121 and the resin frame 125 are integrated by, for example, welding or the like. The outer peripheries 11d of the collector plates 11 in the bipolar electrode 10 are embedded in the resin frame 125. In addition, the outer peripheries of the collector plates 18 and 19 are also embedded in the resin frame 125. The resin constituting the resin frame 125 may be the same as or different from the resin constituting the spacer 121. As such a resin, polypropylene (PP), polyphenylene sulfide (PPS), a modified polyethylene ether (modified PPE), and the like can be exemplified.

[0059] Similar to the resin frame 25 of the first embodiment, the resin frame 125 can be formed by injection molding. Therefore, the inner peripheral surface of the resin frame 125 has a concave shape corresponding to the convex shape of the outer periphery 121b of the spacer 121. The electricity storage device 110 is manufactured by constraining the plurality of bipolar electrodes 10 with the separators 17, the collector plate 18, the collector plate 19, and the frame 120 by using the constraining plates 30A and 30B.

[0060] In such an electricity storage device 101, similar to the electricity storage device 1 of the first embodiment, the collector plates 11 are suppressed from being in direct contact with each other by the plurality of spacers 121 arranged between the collector plates 11 adjacent to each other in the stacking direction. Furthermore, the outer peripheries 11d of the stacked plurality of collector plates 11 are formed in a liquid-tight manner by the resin frame 125 collectively covering the outer peripheries 121b of the plurality of spacers 121, and accordingly, leakage of an electrolytic solution is prevented. In particular, since the outer peripheries 11d of the collector plates 11 are arranged in the resin frame 125, it is possible to bond the resin frame 125 and the collector plates 11 in a liquid-tight manner even more reliably.

[0061] Furthermore, the outer periphery 121b of the spacer 121 protrudes toward the resin frame 125. Furthermore, the distal end of the outer periphery 121b of the spacer 121 extends to a position outside the outer periphery 11d of the collector plate 11. With such a configuration, it is possible to reliably prevent the collector plates 11 and 11, which are adjacent to each other, from contacting each other.

[0062] In addition, since the inner peripheral surface of the resin frame 125 has a concave shape corresponding to the convex shape of the outer periphery 121b of the spacer 121, it is possible to easily allow the spacer 121 and the resin frame 125 to be in close contact with each other.

[0063] In addition, even in a case where the spacer 121 and the resin frame 125 are formed with different materials, it is possible to suppress leakage of an electrolytic solution and the like because the outer peripheries 11d of the collector plates 11 are embedded in the resin frame 125.

[0064] The embodiments of the present invention have been described in detail with reference to the drawings, but the specific configuration is not limited to the embodiments.

[0065] For example, in the first embodiment, the example in which the peripheral edge 11c of the collector plate 11 is held in the spacer 21 is disclosed, but the present invention is not limited to this. For example, the spacers may be welded only to one surface of the collector plate to form a unit, and then the units are stacked. [Third Embodiment]

[0066] An electricity storage device 201 according to a third embodiment will be described with reference to Fig. 6 to 10. The electricity storage device 201 shown in Fig. 6 is used as a battery of various vehicles, such as a forklift, a hybrid vehicle, and an electric vehicle. The electricity storage device 201 includes a plurality of (three in this embodiment) electricity storage modules 202, however, the electricity storage device 201 may have a single electricity storage module 202. The electricity storage module 202 is a bipolar battery. The electricity storage module 202 is, for example, a secondary battery such as a nickel-hydrogen secondary battery or a lithium-ion secondary battery, however, the electricity storage module 202 may be an electric double-layer capacitor. In the following description, a nickel-hydrogen secondary battery is illustrated.

[0067] A plurality of electricity storage modules 202 can be stacked via a conductive plate 203, such as a metal plate. When viewed from a stacking direction D1 (Z direction) of the electricity storage module 202, the electricity storage module 202 and the conductive plate 203 have, for example, a rectangular shape. The conductive plate 203 is also arranged on the outer sides of the electricity storage modules 202 located at both ends in the stacking direction D1. The conductive plate 203 is electrically connected to the adjacent electricity storage modules 202. Therefore, the plurality of electricity storage modules 202 are connected in series in the stacking direction D1. In the stacking direction D1, a positive electrode terminal 204 is connected to the conductive plate 203 located at one end. A negative electrode terminalNegative electrode 205 is connected to a conductive plate 203 located at the other end. The positive electrode terminal 204 may be integrated with the conductive plate 203 to be connected. The negative electrode terminal 205 may be integrated with the conductive plate 203 to be connected. The positive electrode terminal 204 and the negative electrode terminal 205 extend in a direction (X direction) intersecting the stacking direction D1. It is possible to perform charging and discharging of the electricity storage device 201 through the positive electrode terminal 204 and the negative electrode terminal 205.

[0068] The conductive plate 203 can also function as a heat dissipation plate for dissipating the heat generated in the electricity storage module 202. A coolant such as air passes through the plurality of gaps 203a provided inside the conductive plate 203, making it possible to efficiently dissipate heat from the electricity storage module 202 to the outside. Each of the gaps 203a extends, for example, in a direction (Y direction) intersecting the stacking direction D1. When viewed from the stacking direction D1, the conductive plate 203 is smaller than the electricity storage module 202, but the conductive plate 203 may be equal to or larger than the electricity storage module 202.

[0069] The electricity storage device 201 may include a restricting member 206 that restricts the alternately stacked electricity storage modules 202 and conductive plates 203 in the stacking direction D1. The restricting member 206 includes a pair of restricting plates 206A and 206B and connecting members (bolt 207 and nut 208) for connecting the restricting plates 206A and 206B to each other. An insulating film 209, such as a resin film, is interposed between each of the restricting plates 206A and 206B and the conductive plate 203. Each of the restricting plates 206A and 206B is formed with, for example, a metal such as iron. When viewed from the stacking direction D1, each of the restricting plates 206 and 206B and the insulating film 209 has a rectangular shape. The insulating film 209 is larger than the conductive plate 203.The restriction plates 206A and 206B are larger than the electricity storage modules 202. When viewed from the stacking direction D1, an insertion hole H1 into which a shaft portion of the screw 207 is inserted is provided at the edge portion of the restriction plate 206A at a position outside the electricity storage module 202. Similarly, when viewed from the stacking direction D1, an insertion hole H2 into which the shaft portion of the screw 207 is inserted is provided at the edge portion of the restriction plate 206B at a position outside the electricity storage module 202. In a case where each of the restriction plates 206A and 206B has a rectangular shape when viewed from the stacking direction D1, the insertion hole H1 and the insertion hole H2 are located at corners of the restriction plates 206A and 206B.

[0070] One restriction plate 206A abuts against the conductive plate 203, which is connected to the negative electrode terminal 205 via the insulating film 209. The other restriction plate 206B abuts against the conductive plate 203, which is connected to the positive electrode terminal 204 via the insulating film 209. For example, the screw 206 is passed through the insertion hole H1 and the insertion hole H2 from one side of one restriction plate 206A to the other restriction plate 206B side. The nut 208 is threadably engaged with the distal end of the screw 207 projecting from the other restriction plate 206B. Therefore, the insulating film 209, the conductive plate 203 and the electricity storage module 202 are held and united, and a restraining load is applied in the stacking direction D1.

[0071] Fig. 7 is a cross-sectional view schematically illustrating the electricity storage module 202 constituting the electricity storage device 201. Fig. 8 is a cross-sectional view taken along a line VIII-VIII of Fig. 7 is taken. As in Fig. As shown in Figure 7, the electricity storage module 202 includes a stacked body 210 in which a plurality of bipolar electrodes (electrodes) 212 are stacked. When viewed from the stacking direction D1 of the bipolar electrodes 212, the stacked body 210 has, for example, a rectangular shape. A separator 220 may be disposed between the adjacent bipolar electrodes 212.

[0072] The bipolar electrode 212 includes an electrode plate 214 (collector plate), a positive electrode 216 (positive electrode layer) provided on one surface of the electrode plate 214, and a negative electrode 218 (negative electrode layer) provided on the other surface of the electrode plate 214. In the stacked body 210, the positive electrode 216 of one bipolar electrode 212 faces the negative electrode 218 of one bipolar electrode 212 adjacent in the stacking direction D1 with the separator 220 interposed therebetween, and the negative electrode 218 of the bipolar electrode 212 faces the positive electrode 216 of the other bipolar electrode 212 adjacent in the stacking direction D1 with the separator 220 interposed therebetween.

[0073] In the stacking direction D1, the electrode plate 214 (negative electrode side terminal electrode) with the negative electrode 218 arranged on the inside thereof is arranged at one end of the stacked body 210. The electrode plate 214 (positive electrode side terminal electrode) with the positive electrode 216 arranged on the inside thereof is arranged at the other end of the stacked body 210. The negative electrode 218 of the negative electrode side terminal electrode faces the positive electrode 216 of the bipolar electrode 212 of the uppermost layer across the separator 212. The positive electrode 216 of the positive electrode side terminal electrode faces the negative electrode 218 of the bipolar electrode 212 of the lowermost layer across the separator 220. The electrode plates 214 of the terminal electrodes are connected to the adjacent conductive plates 203 (refer to Fig. 6).

[0074] The electricity storage module 202 includes a frame 230 surrounding the side surface of the stacked body 210 extending in the stacking direction D1. The frame 230 may include a first sealing portion 240 (spacer) bonded to the peripheral edge portion 214a of the electrode plate 214 and a second sealing portion 250 (resin frame) provided around the first sealing portion 240 when viewed from the stacking direction D1.

[0075] A first sealing portion 240 is provided for each bipolar electrode 212. The first sealing portion 240 is formed in a frame shape (a rectangular frame shape in this embodiment) when viewed from the stacking direction D1, and is provided over the entire circumference of the peripheral edge portion of the electrode plate 214. The first sealing portion 240 includes a first portion 241 overlapping with the second sealing portion 250 when viewed from the stacking direction D1, and a second portion 242 extending inward from the second sealing portion 250 when viewed from the stacking direction D1.

[0076] The first portion 241 is a portion of the first sealing portion 240 on the outer peripheral side and is provided to be continuous from the outside of the second portion 242. The first portion 241 is embedded in the second sealing portion 250 to be bonded to the second sealing portion 250. The space between the first portions 241 adjacent to each other in the stacking direction D1 is filled with the second sealing portion 250. As described later, the first portion 241 and the second sealing portion 250 are bonded by, for example, injection molding or hot-plate welding. The length L of the first portion 241 is greater than or equal to the thickness T of the first portion 241 in the stacking direction D1 (L ≥ T).Herein, the length L of the first portion 241 corresponds to the protrusion amount of the first sealing portion 240 from the side end portion 214b (the end surface facing the direction intersecting the stacking direction D1) of the electrode plate 214.

[0077] The second portion 242 is a portion on the inner peripheral side of the first sealing portion 240. The second portion 242 is bonded to the electrode plate 214. As shown in Fig. 7, in this embodiment, a surface of the second portion 242 in the stacking direction D1 and the edge portion of the side surface of the electrode plate 214 on the side where the positive electrode 214 is provided are joined by, for example, welding. In addition, the second portion 242 is formed so as not to overlap with any of the positive electrode 216 and the negative electrode 218 when viewed from the stacking direction D1. That is, when viewed from the stacking direction D1, the width of the second portion 242 in the direction perpendicular to the stacking direction D1 is set such that a gap is formed between the inner surface 240a (i.e., the inner surface of the second portion 242) of the first sealing portion 240 and each of the positive electrode 216 and the negative electrode 218.

[0078] The second portion 242 has a portion that overlaps with the separator 222 when viewed from the stacking direction D1. In this embodiment, a step portion 243 having a smaller thickness in the stacking direction D1 than the other portion of the first sealing portion 240 is formed in the inner portion of the second portion 242. The step portion 243 is provided on the other surface (the surface opposite to the surface bonded to the electrode plate 214) of the second portion 242 in the stacking direction D1. A peripheral edge portion 220a of the separator 220 is disposed in the step portion 243. That is, in this embodiment, the step portion 243 corresponds to the above-described portion that overlaps with the separator 220.

[0079] In addition, Fig. 7, the height (length in the stacking direction D1) of the step portion 243 is set to be equal to the height of the separator 220. However, the height of the step portion 243 may be greater than the height of the separator 220 or may be smaller than the height of the separator 220. Furthermore, it is not necessary to provide the step portion 243 in the second portion 242, and the separator 220 may be arranged to overlap with at least a part of the second portion 242. In addition, in Fig. 7, the first sealing portion 240 bonded to one electrode plate 214 and the other electrode plate 214 adjacent to the one electrode plate 214 on the positive electrode 216 side of the one electrode plate 214 are separated from each other with the separator 220 interposed therebetween. However, the thickness T of the first sealing portion 240 may be set such that the first sealing portion 240 and the other electrode plate 214 are in contact with each other.

[0080] The second sealing portion 250 is a tubular member extending in the stacking direction D1 as an axial direction. The second sealing portion 250 is formed in a rectangular frame shape when viewed from the stacking direction D1 (referring to Fig. 8). The second sealing portion 250 extends over the entire length of the stacked body 210 in the stacking direction D1 (referring to Fig. 7). The first portions 241 of the plurality of first sealing portions 240 arranged in the stacking direction D1 are embedded in the second sealing portion 250. The inner surface 250a of the second sealing portion 250 is in contact with the side end portion 214b of the electrode plate 214. An internal space, which is airtightly partitioned by the electrode plates 214 and 214, the first sealing portion 240, and the second sealing portion 250, is formed between the electrode plates 214 and 214 adjacent to each other in the stacking direction D1. The internal space contains an electrolytic solution (not shown) made of, for example, an alkaline solution such as an aqueous potassium hydroxide solution.

[0081] The electrode plate 214 is a rectangular metal foil made of nickel, for example. The peripheral edge portion 214a and the side end portion 214b of the electrode plate 214 are uncoated areas that are not coated with the positive electrode active material and the negative electrode active material. Nickel hydroxide, for example, can be exemplified as the positive electrode active material constituting the positive electrode 216. A hydrogen storage alloy, for example, can be exemplified as the negative electrode active material constituting the negative electrode 218. The formation area of ​​the negative electrode 218 on the other surface of the electrode plate 214 is slightly larger than the formation area of ​​the positive electrode 216 on one surface of the electrode plate 214.

[0082] The separator 220 is formed, for example, in a sheet shape. The separator 220 has, for example, a rectangular shape. The separator 220 is made of a porous resin. The separator 220 is made, for example, of a nonwoven fabric, which is a type of porous resin. As a material constituting the separator 220, a porous film made of a polyolefin resin such as polyethylene (PE) or polypropylene (PP), a woven fabric made of polypropylene, or the like, and the like are exemplified. In addition, the separator 220 may be reinforced with a vinylidene fluoride resin compound or the like. In addition, the separator 220 is not limited to a sheet shape, and a bag-shaped separator may be used.

[0083] As the resin material constituting the frame 230 (the first sealing portion 240 and the second sealing portion 250), for example, polypropylene (PP), polyphenylene sulfide (PPS), modified polyphenylene ether (modified PPE), or the like can be exemplified.

[0084] Next, a method for manufacturing the electricity storage device 201 (mainly, the electricity storage module 202) will be described. The method for manufacturing the electricity storage device 201 according to this embodiment includes the first process of fixing the second portions 242 of the first sealing portions 240 to the peripheral edge portions 214a of the electrode plates 214a in the bipolar electrodes 212, a second process of stacking the plurality of bipolar electrodes 212 to which the first sealing portions 240 are fixed, and a third process of forming the second sealing portion 250 on the outer sides of the first sealing portions 240 fixed to the stacked bipolar electrodes 212.

[0085] In the first process, the second portions 242 of the first sealing portions 240 are fixed to the peripheral edge portions 214a of the electrode plates 214 provided with the positive electrode 216 and the negative electrode 218 by welding or the like. Then, the peripheral edge portion 220a of the separator 220 is arranged on the step portion 243 provided in the second portion 242.

[0086] In the second process, the plurality of bipolar electrodes 212 to which the first sealing portions 240 are fixed by the first process are stacked. Therefore, the stacked body 210 is formed (referring to Fig. 7). When the second process is completed, the second sealing portion 250 is not formed.

[0087] In the third process, the second sealing portion 250 is formed such that the first portion 241 (i.e., the portion protruding outward from the side end portion 214b of the electrode plate 214 when viewed from the stacking direction D1) of the first sealing portion 240 is embedded in the second sealing portion 250. The second sealing portion 250 can be formed by injection molding similar to the method described in the first embodiment (referring to Fig. 4). Alternatively, the second sealing portion 250 may be formed by hot-element welding of the first portion 241 of the first sealing portion 240.

[0088] Fig. 9 is a view illustrating the hot-plate welding of the second sealing portion 250 to the first sealing portion 240. Hereinafter, as an example, the second sealing portion 250, which is formed in a rectangular frame shape when viewed from the stacking direction D1, is divided into four plate-shaped members 251 corresponding to respective sides of the rectangular frame when viewed from the stacking direction D1. Then, one plate-shaped member 251 is welded to a portion corresponding to one side of the first sealing portion 240, which is formed in a rectangular frame shape when viewed from the stacking direction D1, by hot-plate welding. Specifically, as shown in Fig. As shown in Fig. 9, a molten portion 251a of the plate-shaped member 251, which is molten by surface heating, is pressed against the first portion 241 of the first sealing portion 240 in a direction facing the outer surface 240b of the first sealing portion 240. Accordingly, the first portion 241 is welded to the plate-shaped member 251 to be embedded in the molten portion 251a. Such hot-plate welding is performed for each of the four sides of the first sealing portion 240. Therefore, the four plate-shaped members 251 are welded to the first portion 241 and are formed into a rectangular frame shape to surround the periphery of the stacked body 210.In the first sealing portion 240, a protrusion amount (i.e., the length L of the first portion 241) of the first sealing portion 240 from the side end portion 214b of the electrode plate 214 is ensured to be equal to or greater than a certain value (L ≥ T), so that the above-described hot-melt welding work is simplified. Finally, the second sealing portion 250 is formed by bonding the end portions of the adjacent plate-shaped members 251 by welding or the like. However, the procedure for forming the second sealing portion 250 by hot-melt welding is not limited to the above-described procedure. For example, the second sealing portion 250 may be divided into two plate-shaped members formed in an L-shape to correspond to two adjacent sides of a rectangular frame viewed from the stacking direction D1.In this case, the respective plate-shaped members formed in an L-shape are welded to portions corresponding to the two adjacent sides of the first sealing portion 240 by hot-plate welding, and the end portions of the plate-shaped members are bonded to each other by welding or the like, so that the second sealing portion 250 can be formed.

[0089] Through the first to third processes described above, electricity storage module 202 is formed (referring to Fig. 7). A plurality of (three in this embodiment) electricity storage modules 202 are provided by the same processes. Thereafter, as in Fig. 7, the electricity storage device 201 is manufactured by constraining the electricity storage modules 202, the conductive plates 203, and the insulating films 209 by the constraining member 206.

[0090] In the electricity storage device 201 described above, the first sealing portion 240 (spacer) has a first portion 241 that overlaps with the second sealing portion 250 (resin frame) when viewed from the stacking direction D1, and a second portion 242 that extends inward from the second sealing portion 250 when viewed from the stacking direction D1. The first portion 241 is bonded to the second sealing portion 250. The second portion 242 is bonded to the electrode plate 214 (collector plate). According to such a configuration, since the rigidity of the electrode plate 214 can be improved by the second portion 242 bonded to the electrode plate 214, it is possible to suppress deformation of the electricity storage device 201 due to an external force such as internal pressure.

[0091] Furthermore, the second portion 242 does not overlap with any of the positive electrode 214 (positive electrode layer) and the negative electrode 218 (negative electrode layer) when viewed from the stacking direction D1, and the second portion 242 has a portion that overlaps with the separator 220 when viewed from the stacking direction D1. In this embodiment, the second portion 242 has the step portion 243 as a portion that overlaps with the separator 220. According to such a configuration, since the range in which the first sealing portion 240 and the separator 220 overlap with each other can be properly secured, it is possible to effectively suppress a short circuit between the electrode plates 214 adjacent to each other in the stacking direction D1.

[0092] Furthermore, the first sealing portion 240 and the second sealing portion 250 may be formed with the same material. For example, in a case where the first sealing portion 240 and the second sealing portion 250 are integrated by welding (injection molding or hot plate welding, or the like) as described above, it is desirable that the first sealing portion 240 and the second sealing portion 250 be formed with the same material.

[0093] Furthermore, the first sealing portion 240 is formed into a frame shape (a rectangular frame shape in this embodiment) when viewed from the stacking direction D1. With such a configuration, it is possible to simplify the shape of the first sealing portion 240.

[0094] Furthermore, a protrusion amount (i.e., the length L of the first portion 241) of the first sealing portion 240 from the side end portion 214b (the end surface facing a direction intersecting the stacking direction D1) of the electrode plate 214 is equal to or greater than a thickness of the first sealing portion 240 in the stacking direction D1. According to such a configuration, it is possible to alleviate restrictions on a design method at the time of forming the second sealing portion 250. As described above, it is easy to bond the second sealing portion 250 to the first sealing portion 240 by hot-plate welding using the protrusion portion (i.e., the first portion 241) of the first sealing portion 240 having a protrusion amount (length L) equal to or greater than a predetermined value.

[0095] Furthermore, as described above, the second sealing portion 250 may be formed by injection molding or may be formed by hot-melt welding to the first sealing portion 240. According to such a configuration, it is possible to form the peripheral edge of the stacked plurality of bipolar electrodes 212 in a liquid-tight manner by the second sealing portion 250, and it is possible to prevent leakage of an electrolytic solution. [Modified example of the third embodiment]

[0096] In the third embodiment, the electricity storage module 202 may further include a connecting portion 260 that connects end portions (peripheral edge portions) of the first sealing portion 240 adjacent to each other in the stacking direction D1. Fig. 10 is a view schematically illustrating an example of the connecting portion 260 (portion surrounded by a dashed line figure 10). The connecting portion 260 can be formed, for example, by forming molten portions by heating the outer surfaces 240b (refer to Fig. 9) of the adjacent first sealing portions 240 and bonding the fused portions formed in the corresponding adjacent first sealing portions 240. By forming such a bonding portion 260, it is possible to suppress warping of the peripheral edge portion of the first sealing portion 240 in the stacking direction D1, and accordingly, it is possible to effectively suppress the occurrence of stacking misalignment of the plurality of bipolar electrodes 212.

[0097] In the method of manufacturing the electrode storage device 201, in the case of forming the connecting portion 260, a process of connecting the end portions of the first sealing portion 240 adjacent to each other in the stacking direction D1 is performed before the above-described third process. In this process, for example, the above-described heat treatment and bonding processing of molten portions are performed, so that the connecting portion 260 is formed. According to such a configuration, the second sealing portion 250 can be formed in the third process in a state where warpage of the peripheral edge portion of the first sealing portion 240 in the stacking direction D1 is suppressed. As a result, it is possible to effectively suppress occurrence of stacking misalignment of the plurality of bipolar electrodes 212.

[0098] In addition, the connecting portion 240 connecting the adjacent first sealing portions 240 may not be provided over the entire circumference of the peripheral edge portion of the first sealing portion 240, but may be provided at a portion of the peripheral edge portion of the first sealing portion 240. For example, the connecting portion 260 may be provided in a dot shape at certain intervals on the peripheral edge portion of the first sealing portion 240. In addition, in the example of Fig. 10 a gap between the inner surface 260a of the connecting portion 260 and the side end portion 214b of the electrode plate 214. However, the inner surface 260a of the connecting portion 260 and the side end portion 214b of the electrode plate 214 may be in contact with each other. List of reference symbols

[0099] 1, 101, 201: electricity storage device, 10, 212: bipolar electrode, 11: collector plate, 13: positive electrode layer, 15: negative electrode layer, 17, 220: separator, 21, 121: spacer, 25, 125: resin frame, 202: electricity storage module, 214: electrode plate (collector plate), 216: positive electrode (positive electrode layer), 218: negative electrode (negative electrode layer), 230: frame, 240: first sealing portion (spacer), 241: first portion, 242: second portion, 250: second sealing portion (resin frame), 260: connecting portion.

Claims

[1] An electricity storage device (1, 101, 201) in which a plurality of electrodes (10, 212), in which a positive electrode layer (13) is provided on one surface of a collector plate (11) and a negative electrode layer (15) is provided on the other surface of the collector plate (11), are stacked via separators (17, 220), the electricity storage device (1, 101, 201) comprising: a plurality of spacers (21, 121) arranged along peripheral edges of the collector plates (11) between the collector plates (11) adjacent to one another in a stacking direction; and a resin frame (25, 125) covering outer peripheries of the plurality of spacers (21, 121) when viewed from the stacking direction, wherein the spacer (21, 121) has a first portion (241) overlapping with the resin frame (25, 125) when viewed from the stacking direction and a second portion (242) extending inward from the resin frame (25, 125) when viewed from the stacking direction, wherein the first portion (241) is bonded to the resin frame (25, 125), wherein the second portion (242) is bonded to the collector plate (11), wherein the resin frame (25, 125) is formed by injection molding, wherein an outer periphery (21b, 121b) of the spacer (21, 121) and an inner peripheral surface of the resin frame (25, 125) are integrated by welding, and wherein the resin frame (25, 125) collectively covers the outer peripheries of the plurality of spacers (21, 121). [2] Electricity storage device according to claim 1, wherein the second portion (242) does not overlap with either of the positive electrode layer (13) and the negative electrode layer (15) when viewed from the stacking direction, and wherein the second portion (242) has a portion overlapping with the separator (17, 220) when viewed from the stacking direction. [3] The electricity storage device according to claim 1 or 2, wherein the spacer (21, 121) and the resin frame (25, 125) are formed with the same material. [4] The electricity storage device according to any one of claims 1 to 3, wherein the spacer (21, 121) is formed in a frame shape when viewed from the stacking direction. [5] The electricity storage device according to any one of claims 1 to 4, further comprising a connecting portion (260) connecting end portions of the spacers (21, 121) adjacent to each other in the stacking direction. [6] The electricity storage device according to any one of claims 1 to 5, wherein a protrusion amount of the spacer (21, 121) from an end surface of the collector plate (11) facing in a direction intersecting the stacking direction is equal to or larger than a thickness of the spacer (21, 121) in the stacking direction. [7] An electricity storage device (1, 101, 201) in which a plurality of electrodes (10, 212), in which a positive electrode layer (13) is provided on one surface of a collector plate (11) and a negative electrode layer (15) is provided on the other surface of the collector plate, are stacked via separators (17, 220), the electricity storage device (1, 101, 201) comprising: a plurality of spacers (21, 121) arranged along peripheral edges of the collector plates (11) between the collector plates (11) adjacent to one another in a stacking direction; and a resin frame (25, 125) covering outer peripheries of the plurality of spacers (21, 121), wherein an outer periphery of the collector plate (11) is arranged in the resin frame (25, 125), wherein the outer periphery of the spacer (21, 121) has a convex shape towards the resin frame (25, 125), and wherein the resin frame (25, 125) collectively covers the outer peripheries of the plurality of spacers (21, 121). [8] The electricity storage device according to claim 7, wherein the spacer (21, 121) and the resin frame (25, 125) are formed with the same material. [9] The electricity storage device according to claim 7, wherein the spacer (21, 121) and the resin frame (25, 125) are formed with different materials. [10] An electricity storage device according to any one of claims 7 to 9, wherein a distal end of the outer periphery of the spacer (21, 121) extends to a position outside the outer periphery of the collector plate (11). [11] The electricity storage device according to any one of claims 7 to 10, wherein an inner peripheral surface of the resin frame (25, 125) has a concave shape corresponding to the convex shape of the outer periphery of the spacer (21, 121). [12] An electricity storage device according to any one of claims 7 to 11, wherein a continuous cut is formed from the outer periphery on the peripheral edge of the collector plate (11). [13] A method of manufacturing an electricity storage device (1, 101, 201), comprising the following processes: fixing spacers (21, 121) to peripheral edges of collector plates (11) in electrodes (10, 212) in which a positive electrode layer (13) is provided on one surface of the collector plate (11) and a negative electrode layer (15) is provided on the other surface of the collector plate (11); stacking a plurality of electrodes (10, 212) to which the spacers (21, 121) are fixed; fixing a mold (K) to the outer peripheries (21b, 121b) of the stacked spacers (21, 121) so that the outer peripheries (21b, 121b) are exposed within the mold (K), and forming a resin frame (25, 125) by injection molding so as to collectively cover outer peripheries of the spacers (21, 121) fixed to the stacked plurality of electrodes (10, 212). [14] A method of manufacturing an electricity storage device according to claim 13, further comprising a process of joining end portions of the adjacent spacers (21, 121) before the process of forming the resin frame (25, 125).

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