JP2020031023A - Power storage module and manufacturing method for power storage module - Google Patents

Abstract

To provide a power storage module capable of reducing a quantity of discharged electrolyte.SOLUTION: A power storage module 2 comprises: an electrode stack body 15; electrolytes arranged in a plurality of internal spaces V provided in the electrode stack body 15; a frame body 16 disposed to surround the electrode stack body 15 and having a plurality of communication holes 25 allowed to respectively communicate with the plurality of internal spaces V; and a pressure adjustment valve 12 provided on the frame body 16 and having a plurality of communication holes 37 allowed to respectively communicate with the plurality of communication holes 25. Respective openings 37h of the communication holes 37 do not overlap respective openings 25h of the communication holes 25.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a power storage module and a method for manufacturing a power storage module.

  As a conventional battery module, for example, a thin battery as described in Patent Document 1 is known. The thin battery described in Patent Document 1 has a positive electrode, a negative electrode and a bipolar electrode having a current collector, a separator and an electrolyte layer containing an electrolytic solution, and is arranged on one main surface of the current collector so as to surround the positive electrode. A first seal portion, a second seal portion disposed on the other main surface of the current collector so as to surround the negative electrode, and a tube penetrating the second seal portion are provided. One end of the tube faces the internal space defined by the separator, the current collector, and the second seal portion, and the other end of the tube faces the external space of the second seal portion. Gas generated inside the battery is discharged to the outside of the battery via the tube.

JP 2010-287451 A

  In the above prior art, the tube functions as a valve that discharges gas in the internal space when the pressure in the internal space increases. On the other hand, when the gas in the internal space is discharged, the electrolyte may be discharged to the outside. When the electrolytic solution is discharged to the outside, the electrolytic solution in the internal space may be reduced and the battery characteristics may be deteriorated.

  Therefore, an object of the present invention is to provide a power storage module capable of reducing the discharge amount of an electrolyte and a method for manufacturing the power storage module.

  The power storage module according to the present invention includes an electrode stack including a plurality of bipolar electrodes stacked on each other, an electrolytic solution disposed in a plurality of internal spaces provided in the electrode stack, and an electrode stack disposed so as to surround the electrode stack. And a frame having a plurality of first communication holes communicated with each of the plurality of internal spaces, and a pressure provided in the frame and having a plurality of second communication holes respectively communicated with the plurality of first communication holes. A first communication hole in the first surface of the frame body on the side of the pressure adjustment valve, and a second communication hole in the second surface of the pressure adjustment valve on the side of the frame body. The hole is open, and the opening of the second communication hole on the second surface does not overlap with the opening of the first communication hole on the first surface when viewed from a first direction intersecting the first surface.

  In this power storage module, the frame provided so as to surround the electrode stack has a first communication hole communicating with the internal space in which the electrolytic solution is arranged. Further, the pressure regulating valve provided in the frame has a second communication hole that communicates with the first communication hole. Therefore, when the pressure in the internal space increases, the gas in the internal space is discharged through the first communication hole and the second communication hole, and the pressure in the internal space is adjusted. In particular, in this power storage module, the opening of the second communication hole on the second surface of the pressure regulating valve corresponds to the opening of the first communication hole on the first surface when viewed from the direction intersecting the first surface of the frame. Not duplicate. In other words, the opening of the second communication hole is shifted with respect to the opening of the first communication hole. Therefore, when this power storage module is used (installed), the opening of the second communication hole of the pressure adjustment valve located on the outer side can be arranged vertically above the opening of the first communication hole. Therefore, according to this power storage module, the discharge amount of the electrolytic solution can be reduced.

  In the power storage module according to the present invention, the frame includes a plurality of first portions provided on a peripheral portion of each bipolar electrode, and a frame-shaped second portion provided to surround the electrode stack and the first portion. A first portion includes a first surface, the second portion has a plurality of third communication holes that are communicated with the plurality of first communication holes, and includes a first portion and a second portion. A third communication hole may be opened in the third surface on the side, and the second communication hole may be connected to the first communication hole via the third communication hole. Thus, the frame may be configured to include the first portion and the second portion.

  In the power storage module according to the present invention, as viewed from the first direction, the opening of the second communication hole on the second surface may not overlap with the opening of the third communication hole on the third surface. In this case, the opening of the second communication hole of the pressure regulating valve does not overlap with the opening of the third communication hole of the second portion located on the outer side in addition to the opening of the first communication hole of the first portion. Therefore, the discharge amount of the electrolytic solution can be reliably reduced.

  In the power storage module according to the present invention, a first joining protrusion for joining the frame and the pressure regulating valve to each other is formed on one of the second surface and the third surface. The joining first end surface of the one joining projection may be inclined with respect to one surface. In this case, the frame and the pressure regulating valve are joined using the inclined end surface of the joining projection. As a result, the frame and the pressure regulating valve are inclined with respect to each other. As a result, a configuration in which the opening of the second communication hole of the pressure adjusting valve does not overlap with the opening of the first communication hole of the frame body can be easily and reliably realized.

  In the power storage module according to the present invention, the other of the second surface and the third surface is provided with a second joining projection for joining the frame and the pressure regulating valve to each other. The joining second end surface of the joining projection is inclined with respect to the other surface, and the inclination angle of the first end surface and the inclination angle of the second end surface are such that the first end surface and the second end surface are joined to each other. Then, the angle between the second surface and the third surface may be set to be larger than each of the inclination angle of the first end surface and the inclination angle of the second end surface. In this case, the frame and the pressure regulating valve are joined using the inclined end surfaces of the joining projections provided on both the frame and the pressure regulating valve. Therefore, the angle between the frame and the pressure regulating valve (the angle between the third surface and the second surface) can be distributed to the inclination angles of the end surfaces of the respective joining projections. Therefore, when a fixed angle is formed between the frame and the pressure regulating valve, the inclination angle of the end face of each joining projection can be made relatively small. As a result, it is possible to suppress an increase in the amount of protrusion of the joining protrusion, and to form the joining protrusion with high accuracy by, for example, injection molding.

  The method for manufacturing a power storage module according to the present invention includes an electrode stack including a plurality of bipolar electrodes stacked on each other, an electrolytic solution disposed in a plurality of internal spaces provided in the electrode stack, and surrounding the electrode stack. And a pressure regulating valve having a plurality of second communication holes, and a frame body having a plurality of first communication holes communicated with each of the plurality of internal spaces. Preparing the second step, and after the first and second steps, joining the pressure regulating valve to the frame so that each of the first communication hole and each of the second communication hole communicate with each other. And a joining projection for connecting the frame and the pressure regulating valve to each other is formed on at least one of the frame and the pressure regulating valve. In the third step, the joining projection is formed. Using the inclined end face of Opening of the second communicating hole in the force regulating valve so as not to overlap is arranged above the opening of the first communication holes in the frame member, to join the frame and the pressure control valve with each other.

  According to this manufacturing method, as described above, it is possible to manufacture a power storage module capable of reducing the discharge amount of the electrolytic solution. In particular, in this manufacturing method, when joining the pressure regulating valve to the frame, the inclined end surface of the joining projection provided on at least one of the frame and the pressure regulating valve is used. Therefore, a configuration in which the opening of the second communication hole of the pressure regulating valve does not overlap with the opening of the first communication hole of the frame body can be easily and reliably realized.

  The power storage module according to the present invention includes an electrode stack including a plurality of bipolar electrodes stacked on each other, an electrolytic solution disposed in a plurality of internal spaces provided in the electrode stack, and an electrode stack disposed so as to surround the electrode stack. And a frame having a plurality of first communication holes communicated with each of the plurality of internal spaces, and a pressure provided in the frame and having a plurality of second communication holes respectively communicated with the plurality of first communication holes. A first communication hole in the first surface of the frame body on the side of the pressure adjustment valve, and a second communication hole in the second surface of the pressure adjustment valve on the side of the frame body. The hole is open, and the opening of the second communication hole on the second surface does not overlap with the position of the liquid surface of the electrolyte on the first surface when viewed from a first direction intersecting the first surface.

  In this power storage module, the frame provided so as to surround the electrode stack has a first communication hole communicating with the internal space in which the electrolytic solution is arranged. Further, the pressure regulating valve provided in the frame has a second communication hole that communicates with the first communication hole. Therefore, when the pressure in the internal space increases, the gas in the internal space is discharged through the first communication hole and the second communication hole, and the pressure in the internal space is adjusted. In particular, in this power storage module, when viewed from the direction intersecting the first surface of the frame, the opening of the second communication hole in the second surface of the pressure regulating valve is located on the first surface at the position of the liquid level of the electrolyte. Is not duplicated. Therefore, when this power storage module is used (installed), the opening of the second communication hole of the pressure regulating valve located on the outer side is positioned vertically above the liquid surface of the electrolyte on the first surface of the frame. Can be placed. Therefore, according to this power storage module, the discharge amount of the electrolytic solution can be reduced.

  Advantageous Effects of Invention According to the present invention, it is possible to provide a power storage module capable of reducing the amount of discharged electrolyte and a method for manufacturing the power storage module.

FIG. 1 is a schematic cross-sectional view illustrating a power storage device including a battery module according to one embodiment. FIG. 2 is a schematic cross-sectional view of the power storage module shown in FIG. FIG. 2 is a schematic perspective view of the power storage module shown in FIG. FIG. 4 is an exploded perspective view (including a partial cross section) showing a part of the power storage module shown in FIGS. FIG. 5 is an enlarged view of a cross section of FIG. 4. It is a figure showing one process of an electric storage module manufacturing method concerning one embodiment. It is a figure showing one process of an electric storage module manufacturing method concerning one embodiment. It is a figure showing one process of an electric storage module manufacturing method concerning one embodiment.

  Hereinafter, an embodiment will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same reference numerals are used for the same or equivalent elements, and duplicate description may be omitted. Further, in each drawing, an orthogonal coordinate system defined by an X axis, a Y axis, and a Z axis may be shown.

  FIG. 1 is a schematic cross-sectional view illustrating a power storage device including a battery module according to one embodiment. In FIG. 1, a power storage device 1 is used as a battery of a vehicle such as a forklift, a hybrid vehicle, and an electric vehicle. The power storage device 1 includes a plurality (here, three) of power storage modules 2. The power storage module 2 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. In the following description, a nickel-metal hydride secondary battery is exemplified.

  The plurality of power storage modules 2 are stacked via a metal conductive plate 3. The conductive plates 3 are also arranged outside the power storage modules 2 located at both ends in the stacking direction (here, the Z-axis direction). The power storage module 2 and the conductive plate 3 have, for example, a rectangular shape (rectangular shape in plan view) when viewed from the laminating direction. The conductive plate 3 is electrically connected to an adjacent power storage module 2. Thus, the plurality of power storage modules 2 are connected in series in the stacking direction.

  A positive electrode terminal 4 is connected to the conductive plate 3 located at one end (here, the lower end) in the stacking direction. A negative electrode terminal 5 is connected to the conductive plate 3 located at the other end (here, the upper end) in the stacking direction. The positive electrode terminal 4 and the negative electrode terminal 5 extend in a direction (here, the X-axis direction) intersecting (orthogonal) with the laminating direction. By providing such a positive electrode terminal 4 and a negative electrode terminal 5, charging and discharging of the power storage device 1 can be performed.

  The conductive plate 3 can also function as a heat radiating plate for releasing heat generated in the power storage module 2. The conductive plate 3 is provided with a plurality of gaps 3a extending in a direction (here, the Y-axis direction) intersecting (or orthogonal) with the laminating direction and the extending direction of the positive electrode terminal 4 and the negative electrode terminal 5. By passing a coolant such as air through these gaps 3a, heat from the power storage module 2 can be efficiently released to the outside.

  In addition, the power storage device 1 includes a restraining unit 6 that restrains the power storage module 2 and the conductive plate 3 in the stacking direction. The restraining unit 6 includes a pair of restraining plates 7 that sandwich the power storage module 2 and the conductive plate 3 in the stacking direction, and a plurality of sets of bolts 8 and nuts 9 that fasten the restraining plates 7 to each other.

  The constraint plate 7 is formed of a metal such as iron. An insulating film 10 such as a resin film is disposed between each of the constraint plates 7 and the conductive plate 3. The constraint plate 7 and the insulating film 10 have, for example, a rectangular shape in a plan view. With the shaft 8a of the bolt 8 inserted through the insertion hole 7a provided in each restraint plate 7, the nut 9 is screwed into the tip of the shaft 8a, so that the power storage module 2, the conductive plate 3, and the insulating film 10 is subjected to a constraint load in the stacking direction.

  FIG. 2 is a schematic sectional view of the power storage module shown in FIG. FIG. 3 is a schematic perspective view of the power storage module shown in FIG. 2 and 3, the power storage module 2 has a structure in which a plurality of cells (for example, 24 cells) are stacked (a plurality of cells). The power storage module 2 includes a module main body 11 and a plurality (four in this case) of pressure regulating valves 12 attached to one side surface of the module main body 11.

  The module body 11 has an electrode stack 15 including a plurality of bipolar electrodes (a plurality of electrodes) 13 stacked on each other. As an example, the stacking direction of bipolar electrodes 13 matches the stacking direction of power storage module 2. The bipolar electrodes 13 are stacked with a separator 14 interposed therebetween. That is, the electrode stack 15 includes a plurality of separators 14 alternately stacked with the bipolar electrodes 13. Further, the module body 11 has a frame 16 arranged so as to surround the electrode stack 15.

  The bipolar electrode 13 and the separator 14 have, for example, a rectangular shape in a plan view. The separator 14 is disposed between the bipolar electrodes 13 adjacent in the laminating direction. The bipolar electrode 13 includes an electrode plate 17 serving as a current collector, a positive electrode 18 formed on an upper surface 17 a (one surface) of the electrode plate 17, and a negative electrode 19 formed on a lower surface 17 b (the other surface) of the electrode plate 17. And The electrode plate 17 is made of metal, for example, nickel or a nickel-plated steel plate. The electrode plate 17 is a rectangular metal foil made of, for example, nickel.

  The positive electrode 18 of the bipolar electrode 13 faces the negative electrode 19 of one of the bipolar electrodes 13 adjacent in the laminating direction with the separator 14 interposed therebetween. The negative electrode 19 of the bipolar electrode 13 faces the positive electrode 18 of the other bipolar electrode 13 adjacent in the stacking direction with the separator 14 interposed therebetween.

  A positive electrode side termination electrode (electrode) 20 is disposed on the lowermost layer of the electrode laminate 15. The positive terminal electrode 20 has an electrode plate 17 and a positive electrode 18 formed on an upper surface 17 a of the electrode plate 17. On the uppermost layer of the electrode laminate 15, a negative electrode side termination electrode (electrode) 21 is disposed. The negative terminal electrode 21 has an electrode plate 17 and a negative electrode 19 formed on a lower surface 17 b of the electrode plate 17. The positive electrode 18 of the positive terminal electrode 20 faces the negative electrode 19 of the lowermost bipolar electrode 13 with the separator 14 interposed therebetween. The negative electrode 19 of the negative terminal electrode 21 faces the positive electrode 18 of the uppermost bipolar electrode 13 with the separator 14 interposed therebetween. The electrode plates 17 of the positive terminal electrode 20 and the negative terminal electrode 21 are connected to the adjacent conductive plates 3 (see FIG. 1) in the laminating direction.

  The positive electrode 18 is formed by applying a positive electrode active material to one surface of the electrode plate 17. As the positive electrode active material, for example, nickel hydroxide coated with a cobalt (Co) oxide is used. The negative electrode 19 is formed by applying a negative electrode active material to the other surface of the electrode plate 17. As the negative electrode active material, for example, a hydrogen storage alloy is used. The peripheral portion 17c of the electrode plate 17 is an uncoated area where the positive electrode active material and the negative electrode active material are not applied.

  The separator 14 is disposed between the positive electrode 18 and the negative electrode 19, and separates the positive electrode 18 from the negative electrode 19. The separator 14 is smaller than the electrode plate 17 and larger than the positive electrode 18 and the negative electrode 19 when viewed from the laminating direction. The separator 14 is formed in a sheet shape, for example. The separator 14 is formed of a porous film made of a polyolefin resin such as polyethylene (PE) or polypropylene (PP), or a nonwoven fabric or a woven fabric made of PE, PP, methylcellulose, or the like. The separator 14 may be reinforced with a vinylidene fluoride resin compound or the like. In addition, the shape of the separator 14 is not particularly limited to the sheet shape, and may be a bag shape.

  The frame body 16 is disposed around the electrode laminate 15, and includes a plurality of primary seal portions (plural first portions) 22 provided on a peripheral portion 17 c of each electrode plate 17, and the electrode laminate 15 and the primary seal portion. And a secondary seal portion (second portion) 23 provided around the primary seal portion 22 so as to surround the primary seal portion 22.

  Each primary seal portion 22 is arranged for each electrode plate 17 along the laminating direction. The primary seal part 22 is formed in a frame shape. The primary seal portion 22 is joined to the peripheral portion 17c of the electrode plate 17 by, for example, heat welding.

  An internal space V formed by the electrode plate 17 and the primary seal portion 22 is provided between the electrode plates 17 adjacent in the laminating direction. Therefore, a plurality of internal spaces V are provided in the electrode laminate 15. An alkaline electrolyte is disposed (injected) in the internal space V including the inside of the separator 14. As the alkaline electrolytic solution, for example, an alkaline solution containing a potassium hydroxide aqueous solution or the like is used. The primary seal part 22 seals the internal space V. Each cell of the power storage module 2 includes two electrode plates 17, a positive electrode 18, a negative electrode 19, a separator 14, and a primary seal portion 22, and has an internal space V.

  The secondary seal part 23 has a square tubular shape. The secondary seal part 23 further seals the internal space V. The secondary seal part 23 is joined to the primary seal part 22. The secondary seal portion 23 is formed by, for example, injection molding or the like. The primary seal portion 22 and the secondary seal portion 23 are formed of, for example, a resin such as polypropylene (PP), polyphenylene sulfide (PPS), or modified polyphenylene ether (modified PPE).

  Here, FIG. 4 is an exploded perspective view (including a partial cross section) showing a part of the power storage module. FIG. 5 is an enlarged view of a cross section of FIG. As shown in FIGS. 3 to 5, a plurality of (here, four) attachment regions 24 to which the pressure regulating valve 12 is attached are provided on one wall portion 16 a constituting the frame body 16. A plurality of (here, six) communication holes 25 (a plurality of first communication holes) are provided in each of the attachment regions 24 of the primary seal portion 22. The communication holes 25 are arranged in two rows and three rows (two rows in the Y-axis direction and three rows in the Z-axis direction) in the mounting area 24. Therefore, the communication holes 25 are arranged in eight rows and three stages in the wall 16a. The communication holes 25 are respectively connected to the respective internal spaces V of different cells.

  That is, the frame 16 has a plurality of communication holes 25 communicating with each of the plurality of internal spaces V. The communication hole 25 opens in the internal space V and a surface (first surface) 22 s of the frame body 16 on the pressure regulating valve 12 side. The surface 22s is a surface of the primary seal portion 22 on the pressure regulating valve 12 side (secondary seal portion 23 side).

  In each of the attachment regions 24 of the secondary seal portion 23, a plurality (here, six) of communication holes 26 (a plurality of third communication holes) respectively connected to the communication holes 25 are provided. That is, the secondary seal portion 23 has a plurality of communication holes 26 that communicate with the plurality of communication holes 25. The communication hole 26 is open to a surface 23r on the inner space V side (primary seal portion 22 side) of the secondary seal portion 23 and a surface (third surface) 23s on the pressure regulating valve 12 side. The surface 23s is an outer surface of the frame 16. The communication hole 26 is formed in a tapered shape so that the width gradually increases from the surface 23r to the surface 23s. The communication holes 26 are arranged in two rows and three stages in the mounting area 24.

  The communication holes 25 and 26 function as liquid injection holes for injecting the electrolyte into the internal space V. The communication holes 25 and 26 serve as flow paths through which gas generated in the internal space V flows after the electrolyte is injected.

  A joining projection (first joining projection) 27 is provided on a surface 23 s of the secondary seal portion 23. The joining projection 27 is used to join the module main body 11 and the pressure adjustment valve 12. The joining projection 27 forms a plurality of (here, six) flow paths 28 through which the gas from each internal space V flows, in cooperation with the communication hole 26. The channels 28 are arranged in two rows and three stages in each of the mounting areas 24. The flow path 28 has a rectangular shape in a cross section cut in a direction perpendicular to the X-axis direction. The flow paths 28 in one row are shifted from the flow paths 28 in the other row in the stacking direction (Z-axis direction).

  The joining projection 27 has a frame portion 29 that forms the flow channel 28 in one row, and a frame portion 30 that forms the flow channel 28 in the other row. The frame portions 29 and 30 have the same shape and are shifted from each other in the Z-axis direction. A gap extending in the Z-axis direction is formed between the frame portions 29 and 30.

  The pressure regulating valve 12 has a case 33, a plurality of (here, six) valve bodies 34, and a cover 35. The case 33 is formed of, for example, a resin such as PP, PPS, or modified PPE. The case 33 has a bottom wall 36. In the bottom wall portion 36 (that is, the pressure regulating valve 12), a plurality of (in this case, six) communication holes penetrating from the surface (second surface) 36s of the bottom wall portion 36 on the frame 16 side to the cover 35 side. 37 (a plurality of second communication holes) are provided. The surface 36s is an outer surface of the pressure regulating valve 12. These communication holes 37 communicate with the communication holes 25 via the communication holes 26. The communication hole 37 has a circular shape in a cross section cut in a direction perpendicular to the X-axis direction (see FIG. 5). The communication hole 37 is opened inside the case 33 (a housing recess 44a described later) and on the surface 36s.

  A substantially frame-shaped joining projection (second joining projection) 38 is provided on the surface 36s. The joining projection 38 is used to join the module main body 11 and the pressure adjusting valve 12. Further, the joining projections 38 form a plurality (here, six) of flow paths 39 through which the gas from the internal space V flows. The frame 16 and the pressure regulating valve 12 are joined by joining the joining projection 27 and the joining projection 38. The joining protrusion 38 has a shape and dimensions corresponding to the joining protrusion 27. Therefore, the flow path 39 has a rectangular shape in a cross section cut in a direction perpendicular to the X-axis direction. The flow paths 39 in one row are shifted in the Z-axis direction with respect to the flow paths 39 in the other row.

  The joining projection 38 has a frame portion 40 that forms the flow channel 39 in one row, and a frame portion 41 that forms the flow channel 39 in the other row. The frame portions 40 and 41 have the same shape and are shifted from each other in the Z-axis direction. A gap extending in the Z-axis direction is formed between the frame portions 40 and 41.

  Note that the case 33 has an inner wall portion 44 that forms a plurality (here, six) of housing recesses 44 a that house the valve body 34. The inner wall 44 is integrated with the bottom wall 36. The accommodation recess 44a has a circular shape in a cross section cut in a direction perpendicular to the X-axis direction. The accommodation recess 44a can communicate with the communication hole 37.

  The valve body 34 is housed in the housing recess 44 a so as to close the communication hole 37. The valve body 34 is a columnar member formed of an elastic body such as rubber. The valve element 34 opens and closes the communication hole 37. A gap G is provided between the outer surface of the valve body 34 and the inner wall surface of the inner wall portion 44 (see FIG. 6).

  The cover 35 is a plate-like member that closes the opening of the case 33. The cover 35 is formed of, for example, a resin such as PP, PPS, or modified PPE. The cover 35 is joined to the opening end surface of the case 33 by heat welding. The cover 35 also functions as a pressing member that presses the plurality of valve bodies 34 against the bottom wall 36 of the case 33. A housing space S communicating with the housing recess 44a is provided between the inner wall portion 44 of the case 33 and the cover 35. The cover 35 is provided with a plurality of (two in this case) exhaust ports 45. The exhaust port 45 communicates with the accommodation space S.

  In such a pressure regulating valve 12, the communication hole 37 communicates with the internal space V of the module body 11 through the communication hole 26 of the secondary seal part 23 and the communication hole 25 of the primary seal part 22. When the pressure in the internal space V is lower than the set pressure, the communication hole 37 is maintained in a closed state in which the communication hole 37 is closed by the valve body 34. When the pressure in the internal space V rises and becomes equal to or higher than the set pressure, the valve body 34 is elastically deformed so as to be separated from the bottom wall portion 36, and the communication hole 37 is released from the closed state. As a result, the gas from the internal space V is discharged from the exhaust port 45 through the gap between the outer surface of the valve body 34 and the inner wall surface of the inner wall portion 44 and the housing space S.

  Here, as described above, the communication hole 25 is opened in the surface 22 s of the frame body 16 (primary seal portion 22) on the pressure adjustment valve 12 side (see FIG. 5). A communication hole 37 is opened in a surface 36s of the pressure regulating valve 12 (bottom wall portion 36) on the frame 16 side. The openings of the communication hole 37 and the communication hole 25 communicating with each other do not overlap with each other when viewed from a first direction (here, the X-axis direction) intersecting (perpendicular to) the surface 22s. That is, as viewed from the first direction, the opening 37h of the communication hole 37 on the surface 36s does not overlap with the opening 25h of the communication hole 25 (communicating with the communication hole 37) on the surface 22s.

  Further, as described above, the communication hole 26 is opened in the surface 23 s of the secondary seal portion 23 on the pressure regulating valve 12 side. When viewed from the first direction, the openings of the communication hole 26 and the communication hole 25 communicating with each other do not overlap with each other. That is, when viewed from the first direction, the opening 37h of the communication hole 37 on the surface 36s does not overlap with the opening 26h of the communication hole 26 (communicating with the communication hole 37) on the surface 23s.

  Here, that the openings do not overlap each other when viewed from the first direction means that the openings are shifted from each other when viewed from the first direction and their outer edges do not overlap. Here, when viewed from the first direction, the opening 37h and the opening 25h (and the opening 26h) are shifted from each other in the stacking direction (Z-axis direction) (the opening 37h is located vertically above the opening 25h). There). Further, that the openings do not overlap each other when viewed from the first direction means that a region different from the opening is interposed between the openings when viewed from the first direction.

  In the power storage module 2, a configuration in which the above-described opening 37h does not overlap with the openings 25h and 26h can be realized by an arbitrary mode. In the present embodiment, the frame 16 and the pressure adjustment valve 12 are inclined. It is realized by joining. This will be described more specifically. In the power storage module 2, as described above, the joining protrusion 27 is formed on the outer surface 23 s of the secondary seal portion 23, which is the outer surface of the frame 16. The end surface (first end surface) 27s of the joining projection 27 is inclined at an inclination angle α with respect to the surface 23s. The end face 27a is an end face for joining with the pressure regulating valve 12 (joining projection 38).

  A joining projection 38 is formed on a surface 36 s of the bottom wall portion 36, which is an outer surface of the pressure regulating valve 12. The end surface (second end surface) 38a of the joining projection 38 is inclined at an inclination angle β with respect to the surface 36s. The end face 38a is an end face for joining with the frame 16 (joining projection 27). The frame body 16 and the pressure regulating valve 12 are inclined by being joined to each other by using their inclined end surfaces 27a and 38a.

  In particular, the inclination angle α of the end surface 27a and the inclination angle β of the end surface 38a are such that when the end surfaces 27a and 38a are joined to each other, the angle γ between the surfaces 23s and 36s becomes the inclination angle α and the inclination angle β. It is set to be larger than each. Here, the angle γ is the sum of the value of the inclination angle α and the value of the inclination angle β. Thereby, the frame 16 and the pressure adjusting valve 12 are joined at an angle, and a configuration in which the opening 37h does not overlap with the openings 25h and 26h can be realized.

  Here, the relationship between the frame 16 and the pressure regulating valve 12 may be defined by the opening and the level of the electrolytic solution. For example, as viewed from a first direction intersecting the surface 22s on the pressure regulating valve 12 side of the frame 16 (primary seal portion 22), the communication hole on the surface 16s on the frame body 16 side of the pressure regulating valve 12 (bottom wall portion 36). The opening 37h of the 37 does not overlap the position P1 of the liquid surface of the electrolytic solution R on the surface 22s. Furthermore, when viewed from the first direction, the opening 37h of the communication hole 37 on the surface 36s does not overlap with the position P3 of the liquid surface of the electrolytic solution R on the surface 23s. Such a relationship can be realized, for example, by using the bonding protrusions 27 and 38 as described above.

  Subsequently, an example of a power storage module manufacturing method for manufacturing the power storage module 2 will be described. In this manufacturing method, first, a first step of preparing the module main body 11 and a second step of preparing the pressure adjusting valve 12 are performed. The order of the first step and the second step is not limited. Subsequently, after the first step and the second step, the communication holes 25 and 26 on the module main body 11 side and the communication holes 37 on the pressure regulating valve 12 side communicate with each other in the frame 16 so as to communicate with each other. A third step of joining the pressure regulating valve 12 is performed.

  In the third step, the opening 37h of the communication hole 37 in the pressure regulating valve 12 is changed to the openings 25h, 26h of the communication holes 25, 26 in the frame 16 using the inclined end surfaces 27a, 38a of the joining projections 27, 38. The frame 16 and the pressure regulating valve 12 are joined to each other so as not to overlap (or so that the opening 37h of the communication hole 37 does not overlap the positions P1 and P3 of the liquid surface of the electrolytic solution R). More specifically, in the third step, as shown in FIG. 6, first, the module main body 11 and the pressure adjusting valve 12 are arranged so that the joining projections 27 and 38 face each other, and The heating plate 46 is arranged between the pressure control valve 12 and the pressure control valve 12.

  Next, as shown in FIG. 7, the end faces 27a and 38a are brought into contact with the hot plate 46 to melt the end faces 27a and 38a. Then, as shown in FIG. 8, while the end surfaces 27 a and 38 a are being melted, the joining protrusions 27 and 38 are pressed together, so that the joining protrusions 27 and 38 are welded to each other. As a result, the joining projections 27 and 38 are joined to each other, the pressure adjusting valve 12 is provided on the module main body 11, and the power storage module 2 is obtained.

  As described above, in the power storage module 2, the frame 16 has the communication hole 25 that communicates with the internal space V in which the electrolyte is disposed. The pressure regulating valve 12 provided on the frame 16 has a communication hole 37 that communicates with the communication hole 25. Therefore, when the pressure in the internal space V increases, the gas in the internal space V is discharged through the communication holes 25 and the communication holes 37, and the pressure in the internal space V is adjusted. In particular, in the power storage module 2, the opening 37 h of the communication hole 37 in the surface 36 s of the pressure regulating valve 12 overlaps with the opening 25 h of the communication hole 25 in the surface 22 s when viewed from the direction intersecting the surface 22 s of the frame 16. I haven't. In other words, the opening 37h of the communication hole 37 is shifted with respect to the opening 25h of the communication hole 25. Therefore, when the power storage module 2 is used (installed), the opening 37h of the communication hole 37 of the pressure regulating valve 12 located on the outer side can be disposed vertically above the opening 25h of the communication hole 25. Therefore, according to the power storage module 2, the discharge amount of the electrolytic solution can be reduced.

  In the power storage module 2, the frame 16 surrounds the plurality of primary seal portions 22 provided on the peripheral portion 17 c of each electrode (such as the bipolar electrode 13), and the electrode laminate 15 and the primary seal portion 22. And a frame-shaped secondary seal portion 23 provided in the main body. The primary seal portion 22 includes a surface 22s. The secondary seal portion 23 has a plurality of communication holes 26 that communicate with the plurality of communication holes 25. A communication hole 26 is opened in a surface 23 s of the secondary seal portion 23 on the side of the pressure regulating valve 12. The communication hole 37 is connected to the communication hole 25 via the communication hole 26. Thus, the frame 16 may be configured to include the primary seal portion 22 and the secondary seal portion 23.

  In the power storage module 2, the opening 37h of the communication hole 37 on the surface 36s does not overlap with the opening 26h of the communication hole 26 on the surface 23s when viewed from the first direction. Therefore, the opening 37h of the communication hole 37 of the pressure regulating valve 12 is not only the opening 25h of the communication hole 25 of the primary seal portion 22 but also the opening 26h of the communication hole 26 of the secondary seal portion 23 located on the outer side. Not duplicate. Therefore, the discharge amount of the electrolytic solution can be reliably reduced.

  In the power storage module 2, a joining protrusion 27 for joining the frame body 16 and the pressure adjustment valve 12 to each other is formed on the surface 23 s. The joining end surface 27a of the joining projection 27 is inclined with respect to the surface 23s. Therefore, the frame 16 and the pressure regulating valve 12 are joined using the inclined end surface 27a of the joining projection 27. Thereby, the frame 16 and the pressure regulating valve 12 are in a state of being inclined with respect to each other. As a result, a configuration in which the opening 37h of the communication hole 37 of the pressure regulating valve 12 does not overlap the opening 25h of the communication hole 25 of the frame 16 or the like can be easily and reliably realized.

  Further, in the power storage module 2, a joining protrusion 38 for joining the frame body 16 and the pressure regulating valve 12 to each other is provided on the surface 36s. The joining end surface 38a of the joining projection 38 is inclined with respect to the surface 36s. The inclination angle α of the end surface 27a and the inclination angle β of the end surface 38a are defined as follows: when the end surface 27a and the end surface 38a are joined to each other, the angle γ between the surface 36s and the surface 23s becomes the inclination angle α and the inclination angle β. It is set to be larger than each.

  In this case, the frame 16 and the pressure regulating valve 12 are joined using the inclined end surfaces 27a, 38a of the joining projections 27, 38 provided on both the frame 16 and the pressure regulating valve 12. . For this reason, the angle between the frame 16 and the pressure regulating valve 12 can be distributed to the inclination angles α and β of the end faces 27 a and 38 a of the respective joint projections 27 and 38. Therefore, when a fixed angle is formed between the frame 16 and the pressure regulating valve 12, the respective inclination angles α and β can be relatively reduced. As a result, an increase in the amount of protrusion of the joining protrusions 27 and 38 can be suppressed, and the joining protrusions 27 and 38 can be formed with high precision by, for example, injection molding.

  Furthermore, according to the power storage module manufacturing method according to the present embodiment, as described above, the power storage module 2 that can reduce the discharge amount of the electrolyte can be manufactured. In particular, in this manufacturing method, when joining the pressure adjusting valve 12 to the frame 16, the inclined end face of the joining projection provided on at least one of the frame 16 and the pressure adjusting valve 12 is used. Therefore, a configuration in which the opening 37h of the communication hole 37 of the pressure regulating valve 12 does not overlap with the openings 25h and 26h of the communication holes 25 and 26 of the frame 16 can be easily and reliably realized.

  In the power storage module 2, the frame 16 has a communication hole 25 that communicates with the internal space V in which the electrolyte R is disposed. The pressure regulating valve 12 provided on the frame 16 has a communication hole 37 that communicates with the communication hole 25. Therefore, when the pressure in the internal space V increases, the gas in the internal space V is discharged through the communication holes 25 and the communication holes 37, and the pressure in the internal space V is adjusted. In particular, in the power storage module 2, when viewed from the direction intersecting the surface 22 s of the frame 16, the opening 37 h of the communication hole 37 in the surface 36 s of the pressure regulating valve 12 is located at the position of the liquid surface of the electrolytic solution R on the surface 22 s. Does not overlap with P1. Therefore, when using (installing) the power storage module 2, the opening 37 h of the communication hole 37 of the pressure regulating valve 12 located on the outer side is set to be more vertical than the liquid surface of the electrolytic solution R on the surface 22 s of the frame 16. Can be placed above. Therefore, according to the power storage module 2, the discharge amount of the electrolytic solution R can be reduced.

  The above embodiment has described one embodiment of the present invention. Therefore, the present invention is not limited to the above-described power storage module 2 and the manufacturing method thereof, and can be arbitrarily changed.

  For example, in the above embodiment, both the secondary seal portion 23 and the pressure regulating valve 12 are provided with joining projections having inclined end surfaces. However, one of the surface 23s of the secondary seal portion 23 and the surface 36s of the pressure regulating valve 12 may be provided with a joining projection having an inclined end surface. That is, the other of the surface 23 s of the secondary seal portion 23 and the surface 36 s of the pressure regulating valve 12 may not be provided with the joining projection, or may be provided with the joining projection, but the end face of the joining projection is provided. Need not be inclined.

  Further, in the above-described embodiment, the inclination between the frame 16 (that is, the module main body 11) and the pressure regulating valve 12 is provided by utilizing the inclination of the end surfaces 27a and 38a of the joining projections 27 and 38, and the opening 37h is provided. Has been described in which the openings do not overlap the openings 25h and 26h. However, for example, the opening 37h may be prevented from overlapping the openings 25h and 26h by forming the joining projection 38 so that the flow path 39 is bent while the end face 27a and the end face 38a are parallel. Further, the opening 37h may not be overlapped with the openings 25h and 26h by another configuration.

  The above embodiment will be additionally described below.

[Appendix 1]
An electrode stack including a plurality of bipolar electrodes stacked on each other,
An electrolytic solution arranged in a plurality of internal spaces provided in the electrode laminate,
A frame body arranged to surround the electrode stack and having a plurality of first communication holes communicated with the plurality of internal spaces,
A pressure regulating valve provided on the frame body and having a plurality of second communication holes respectively connected to the plurality of first communication holes;
With
The first communication hole is opened in a first surface of the frame body on the side of the pressure adjustment valve,
The second communication hole is opened on a second surface of the pressure regulating valve on the side of the frame,
As viewed from a first direction intersecting the first surface, the opening of the second communication hole in the second surface does not overlap with the position of the electrolyte surface on the first surface.
Power storage module.
[Appendix 2]
The frame includes a plurality of first portions provided at a peripheral portion of each of the bipolar electrodes, and a frame-shaped second portion provided so as to surround the electrode laminate and the first portion. ,
The first portion includes the first surface;
The second portion has a plurality of third communication holes connected to the plurality of first communication holes,
The third communication hole is opened on a third surface of the second portion on the side of the pressure regulating valve,
The second communication hole communicates with the first communication hole via the third communication hole.
The power storage module according to supplementary note 1.
[Appendix 3]
As viewed from the first direction, the opening of the second communication hole on the second surface does not overlap with the position of the electrolyte surface on the third surface.
The power storage module according to supplementary note 2.
[Appendix 4]
On one of the second surface and the third surface, a first joining protrusion for joining the frame body and the pressure regulating valve to each other is formed,
A first end face for joining of the first joining projection is inclined with respect to the one face,
The power storage module according to Supplementary Note 2 or 3.
[Appendix 5]
On the other of the second surface and the third surface, a second joining protrusion for joining the frame and the pressure regulating valve to each other is provided,
The joining second end surface of the second joining projection is inclined with respect to the other surface,
The inclination angle of the first end face and the inclination angle of the second end face are such that when the first end face and the second end face are joined to each other, the angle between the second face and the third face is It is set to be larger than each of the inclination angle of the first end face and the inclination angle of the second end face,
The power storage module according to supplementary note 4.
[Appendix 6]
An electrode stack including a plurality of bipolar electrodes stacked on each other, an electrolytic solution disposed in a plurality of internal spaces provided in the electrode stack, and an electrode disposed so as to surround the electrode stack; A first step of preparing a module body having a frame body having a plurality of first communication holes communicated with the respective spaces;
A second step of preparing a pressure regulating valve having a plurality of second communication holes;
A third step of joining the pressure regulating valve to the frame so that each of the first communication hole and each of the second communication hole communicate with each other after the first step and the second step. ,
With
At least one of the frame and the pressure regulating valve is formed with a joining projection for connecting the frame and the pressure regulating valve to each other,
In the third step, using the inclined end surface of the joining projection, so that the opening of the second communication hole in the pressure regulating valve is disposed above the position of the liquid surface of the electrolyte and does not overlap, Joining the frame and the pressure regulating valve to each other,
A method for manufacturing a power storage module.

  2 ... power storage module, 12 ... pressure regulating valve, 13 ... bipolar electrode (electrode), 16 ... frame, 22 ... primary seal part (first part), 22s ... surface (first surface), 23 ... secondary seal part (Second part), 23s ... surface (third surface), 25 ... communication hole (first communication hole), 25h, 26h, 37h ... opening, 26 ... communication hole (third communication hole), 27 ... joining projection (First joining projection), 27a ... end face (first end face), 36s ... face (second face), 37 ... communication hole (second communication hole), 38 ... joining projection (second joining projection), 38a: end face (second end face), α, β: inclination angle.

Claims (7)

An electrode stack including a plurality of bipolar electrodes stacked on each other,
An electrolytic solution arranged in a plurality of internal spaces provided in the electrode laminate,
A frame body arranged to surround the electrode stack and having a plurality of first communication holes communicated with the plurality of internal spaces,
A pressure regulating valve provided on the frame body and having a plurality of second communication holes respectively connected to the plurality of first communication holes;
With
The first communication hole is opened in a first surface of the frame body on the side of the pressure adjustment valve,
The second communication hole is opened on a second surface of the pressure regulating valve on the side of the frame,
When viewed from a first direction intersecting the first surface, the opening of the second communication hole on the second surface does not overlap with the opening of the first communication hole on the first surface.
Power storage module. The frame includes a plurality of first portions provided at a peripheral portion of each of the bipolar electrodes, and a frame-shaped second portion provided so as to surround the electrode laminate and the first portion. ,
The first portion includes the first surface;
The second portion has a plurality of third communication holes connected to the plurality of first communication holes,
The third communication hole is opened on a third surface of the second portion on the side of the pressure regulating valve,
The second communication hole communicates with the first communication hole via the third communication hole.
The power storage module according to claim 1. When viewed from the first direction, the opening of the second communication hole on the second surface does not overlap with the opening of the third communication hole on the third surface.
The power storage module according to claim 2. On one of the second surface and the third surface, a first joining protrusion for joining the frame body and the pressure regulating valve to each other is formed,
A first end face for joining of the first joining projection is inclined with respect to the one face,
The power storage module according to claim 2. On the other of the second surface and the third surface, a second joining protrusion for joining the frame and the pressure regulating valve to each other is provided,
The joining second end surface of the second joining projection is inclined with respect to the other surface,
The inclination angle of the first end face and the inclination angle of the second end face are such that when the first end face and the second end face are joined to each other, the angle between the second face and the third face is It is set to be larger than each of the inclination angle of the first end face and the inclination angle of the second end face,
The power storage module according to claim 4. An electrode stack including a plurality of bipolar electrodes stacked on each other, an electrolytic solution disposed in a plurality of internal spaces provided in the electrode stack, and an electrode disposed so as to surround the electrode stack; A first step of preparing a module body having a frame body having a plurality of first communication holes communicated with the respective spaces;
A second step of preparing a pressure regulating valve having a plurality of second communication holes;
A third step of joining the pressure regulating valve to the frame so that each of the first communication hole and each of the second communication hole communicate with each other after the first step and the second step. ,
With
At least one of the frame and the pressure regulating valve is formed with a joining projection for connecting the frame and the pressure regulating valve to each other,
In the third step, the opening of the second communication hole in the pressure regulating valve is disposed above the opening of the first communication hole in the frame body by using the inclined end surface of the joining projection, and is overlapped. Not to join the frame and the pressure regulating valve to each other,
A method for manufacturing a power storage module. An electrode stack including a plurality of bipolar electrodes stacked on each other,
An electrolytic solution arranged in a plurality of internal spaces provided in the electrode laminate,
A frame body arranged to surround the electrode stack and having a plurality of first communication holes communicated with the plurality of internal spaces,
A pressure regulating valve provided on the frame body and having a plurality of second communication holes respectively connected to the plurality of first communication holes;
With
The first communication hole is opened in a first surface of the frame body on the side of the pressure adjustment valve,
The second communication hole is opened on a second surface of the pressure regulating valve on the side of the frame,
As viewed from a first direction intersecting the first surface, the opening of the second communication hole in the second surface does not overlap with the position of the electrolyte surface on the first surface.
Power storage module.

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