Patent Publication Number: US-2020280029-A1

Title: Power storage module

Description:
TECHNICAL FIELD 
     An aspect of the present invention relates to an electricity-storage module. 
     BACKGROUND ART 
     Patent Literature 1 discloses a bipolar battery. The bipolar battery includes a battery element including a plurality of sheets of bipolar electrodes which are stacked. The bipolar electrode includes a current collector, a positive electrode layer provided on one surface of the current collector, and a negative electrode layer provided on the other surface of the current collector. In addition, the bipolar battery includes a resin group that covers an outer side of the battery element. The resin group is provided to air-tightly maintain the battery element so that an electrolytic solution inside the battery and the like are not leaked to the outside. 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: Japanese Unexamined Patent Publication No. 2005-005163 
     SUMMARY OF INVENTION 
     Technical Problem 
     In the bipolar battery, for example, when an inner pressure rises, a load is canceled in the bipolar electrode located at an intermediate portion, but the load is not canceled in an outermost bipolar electrode, and thus there is a concern that the current collector and the resin group may be deformed. In this case, a gap occurs between the resin group and the current collector, and thus leakage of the electrolytic solution may occur or breakage of the resin group may occur. Particularly, in a case where the negative electrode layer is located on the outermost portion, and the electrolytic solution is composed of an aqueous alkali solution, leakage of the electrolytic solution from the gap is likely to occur due to a so-called alkali creep phenomenon. In this state, it is preferable to improve reliability by suppressing the leakage or breakage in an electricity-storage module such as the bipolar battery. 
     Here, an object of an aspect of the invention is to provide an electricity-storage module capable of improving reliability. 
     Solution to Problem 
     According to an aspect of the invention, there is provided an electricity-storage module including: a stacked body that includes a plurality of electrodes which are stacked along a first direction; and a sealing body that is provided to the stacked body so as to surround an edge portion of the electrodes. The electrodes include a plurality of bipolar electrodes, a negative terminal electrode, and a positive terminal electrode. The bipolar electrode includes an electrode plate, a positive electrode provided on a first surface of the electrode plate, and a negative electrode provided on a second surface of the electrode plate which is opposite to the first surface. The negative terminal electrode includes the electrode plate and a negative electrode provided on the second surface, and is disposed at one end of the stacked body in the first direction such that the second surface is an inner side of the stacked body. The positive terminal electrode includes the electrode plate and a positive electrode provided on the first surface, and is disposed at the other end of the stacked body in the first direction such that the first surface is an inner side of the stacked body. The sealing body includes a plurality of first sealing portions which are joined to edge portions of the electrodes, and a second sealing portion that is joined to the first sealing portions so as to surround the plurality of first sealing portions from an outer side. The second sealing portion includes a first overlapping portion that is provided on a third sealing portion so as to overlap the third sealing portion as one of the first sealing portions which is joined to an edge portion of the negative terminal electrode at the one end side of the stacked body. The first overlapping portion includes a regulation portion configured to regulate deformation of the third sealing portion along the first direction. 
     In the electricity-storage module, the sealing body is provided in the stacked body of the electrodes. The sealing body includes the first sealing portions joined to the edge portions of the electrodes, and the second sealing portion provided so as to surround the first sealing portions. On the other hand, the negative terminal electrode including the electrode plate and the negative electrode is disposed at the one end of the stacked body of the electrodes. In addition, the second sealing portion includes the first overlapping portion that is provided on the third sealing portion so as to overlap the third sealing portion that is one of the first sealing portions which is joined to the edge portion of the negative terminal electrode. In addition, the first overlapping portion includes the regulation portion configured to regulate deformation of the third sealing portion. According to this, at least on the negative terminal electrode side, deformation of the sealing body or the like is suppressed, and thus leakage or breakage is suppressed. As a result, according to the electricity-storage module, reliability is improved. 
     In the electricity-storage module according to the aspect of the invention, the second sealing portion may include a second overlapping portion provided on a fourth sealing portion so as to overlap the fourth sealing portion as one of the first sealing portions which is joined to an edge portion of the positive terminal electrode at the other end side of the stacked body, and the first overlapping portion may include a portion of which the thickness along the first direction is larger than the thickness of the second overlapping portion as the regulation portion. In this case, reliability can be improved with a simple configuration. In the electricity-storage module according to the aspect of the invention, the thickness of the first overlapping portion along the first direction may be equal to or greater than 300 μm and equal to or less than 3 mm 
     The electricity-storage module according to the aspect of the invention may further include a constraining member that is disposed at the one end side of the stacked body and is configured to apply a constraining load to the stacked body along the first direction, and the thickness of the regulation portion along the first direction may be two or more times the thickness of the first sealing portion along the first direction in a range in which an outer edge of the regulation portion in the first direction is located on a further inner side of the stacked body in comparison to an outer edge of the constraining member. In this case, reliability can be reliably improved while avoiding an increase in size. 
     In the electricity-storage module according to the aspect of the invention, the first overlapping portion may include a portion that extends toward the inner side of the stacked body so as to further overlap the electrode plate of the negative terminal electrode as the regulation portion. Even in this case, reliability can be improved with a simple configuration. 
     According to another aspect of the invention, there is provided an electricity-storage module including: a stacked body that includes a plurality of electrodes which are stacked along a first direction; and a sealing body that is provided to the stacked body so as to surround an edge portion of the electrodes. The electrodes include a plurality of bipolar electrodes, a negative terminal electrode, and a positive terminal electrode. The bipolar electrode includes an electrode plate, a positive electrode provided on a first surface of the electrode plate, and a negative electrode provided on a second surface of the electrode plate which is opposite to the first surface. The negative terminal electrode includes the electrode plate and a negative electrode provided on the second surface, and is disposed at one end of the stacked body in the first direction such that the second surface is an inner side of the stacked body. The positive terminal electrode includes the electrode plate and a positive electrode provided on the first surface, and is disposed at the other end of the stacked body in the first direction such that the first surface is an inner side of the stacked body. The sealing body includes a plurality of first sealing portions which are joined to edge portions of the electrodes, and a second sealing portion that is joined to the first sealing portions so as to surround the plurality of first sealing portions from an outer side. The second sealing portion includes a first overlapping portion that is provided on a third sealing portion so as to overlap the third sealing portion as one of the first sealing portions which is joined to an edge portion of the negative terminal electrode at the one end side of the stacked body. The first overlapping portion includes a first portion having a thickness equal to or larger than the thickness of the second sealing portion on a side surface that intersects the first direction of the stacked body. 
     In the electricity-storage module, the sealing body is provided to the stacked body of the electrodes. The sealing body includes the first sealing portions joined to the edge portions of the electrodes, and the second sealing portion provided so as to surround the first sealing portions. On the other hand, the negative terminal electrode including the electrode plate and the negative electrode is disposed at the one end of the stacked body of the electrodes. In addition, the second sealing portion includes the first overlapping portion that is provided on the third sealing portion so as to overlap the third sealing portion as one of the first sealing portions which is joined to the edge portion of the negative terminal electrode. In addition, the first overlapping portion includes the first portion having a thickness larger than the thickness of the second sealing portion on a side surface that intersects the first direction of the stacked body. According to this, at least on the negative terminal electrode side, deformation of the sealing body or the like is suppressed, and thus leakage or breakage is suppressed. As a result, according to the electricity-storage module, reliability is improved. 
     In the electricity-storage module according to the aspect of the invention, the second sealing portion may include a second overlapping portion provided on a fourth sealing portion so as to overlap the fourth sealing portion as one of the first sealing portions which is joined to an edge portion of the positive terminal electrode at the other end side of the stacked body, and the second overlapping portion may include a second portion having a thickness equal to or greater than the thickness of the second sealing portion on a side surface of the stacked body which intersects the first direction. In this case, even in the positive terminal electrode side, deformation of the sealing body or the like is suppressed, and thus leakage or breakage is suppressed. As a result, according to the electricity-storage module, reliability is reliably improved. 
     Here, in an electricity-storage module, hydrogen is generated on the negative electrode at the first charging due to water in an electrolytic solution. In a case where the negative electrode includes a hydrogen occluding alloy, the hydrogen is occluded to the negative electrode. However, a hydrogen absorbing state is unstable at an inner pressure at the time of typical use, and thus the negative electrode ejects a constant amount of hydrogen. According to this, it enters a state in which hydrogen exists in an inner space. In the electricity-storage module, there is a demand for suppression of transmission of the hydrogen (hydrogen transmission) to the outside. 
     Here, in the electricity-storage module according to the aspect of the invention, the first sealing portion may include an annular extension portion that extends from an edge portion of the electrode to an outer side of the electrode when viewed from the first direction, and the first portion and the second portion may be provided in an annular shape so as to cover the extension portion when viewed from the first direction. 
     In this case, in a region corresponding to the extension portion of the first sealing portion, an electrode is not interposed when viewed from the first direction, and it is considered that hydrogen transmission along the first direction is likely to occur. In contrast, in the electricity-storage module, a first portion and a second portion having a relatively large thickness are provided in a region that overlaps the extension portion when viewed from the first direction. Accordingly, hydrogen transmission from the region is suppressed, and thus reliability is more reliably improved. 
     Advantageous Effects of Invention 
     According to the aspects of the invention, it is possible to provide an electricity-storage module capable of improving reliability. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic cross-sectional view illustrating an embodiment of an electricity-storage device. 
         FIG. 2  is a schematic cross-sectional view illustrating an internal configuration of the electricity-storage module illustrated in  FIG. 1 . 
         FIG. 3  is a schematic cross-sectional view illustrating a joining interface between an electrode plate and a first resin portion. 
         FIG. 4  is an enlarged cross-sectional view of a part of an electricity-storage module according to a comparative example. 
         FIG. 5  is a view for describing a problem that occurs in the electricity-storage module of the comparative example. 
         FIG. 6  is a schematic cross-sectional view illustrating an internal configuration of an electricity-storage module according to a modification example. 
         FIG. 7  is a schematic cross-sectional view illustrating an internal configuration of an electricity-storage module according to another modification example. 
         FIG. 8  is an enlarged view of a main portion illustrated in  FIG. 7 . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, an embodiment of an electricity-storage module will be described with reference to the drawings. Note that, in description of the drawings, the same reference numeral will be given to the same elements or equivalent elements, and redundant description thereof may be omitted in some cases. 
       FIG. 1  is a schematic cross-sectional view illustrating an embodiment of an electricity-storage device. As illustrated in  FIG. 1 , an electricity-storage device  1  may be used, for example, as batteries of various vehicles such as a forklift, a hybrid vehicle, and electric vehicle. The electricity-storage device  1  includes a module stacked body  2  including a plurality of electricity-storage modules  4  which are stacked, and a constraining member  3  that applies a constraining load to the module stacked body  2  in a stacking direction thereof. 
     The module stacked body  2  includes the plurality of (here, three) electricity-storage modules  4 , and a plurality of (here, four) conductive plates  5 . Each of the electricity-storage modules  4  is a bipolar battery, and has a rectangular shape when viewed from a stacking direction. For example, the electricity-storage module  4  is a secondary battery such as a nickel-hydrogen secondary battery and a lithium ion secondary battery, or an electric double-layer capacitor. In the following description, the nickel-hydrogen secondary battery will be exemplified. 
     The electricity-storage modules  4  adjacent to each other in the stacking direction are electrically connected to each other through each of the conductive plates  5 . The conductive plate  5  is disposed between the electricity-storage modules  4  adjacent to each other in the stacking direction, and on an outer side of the electricity-storage modules  4  located at stacking ends. A positive electrode terminal  6  is connected to one of the conductive plates  5  disposed on an outer side of the electricity-storage modules  4  located at the stacking ends, and a negative electrode terminal  7  is connected to the other conductive plate  5  between the conductive plates  5  disposed on an outer side of the electricity-storage modules  4  located at the stacking ends. For example, the positive electrode terminal  6  and the negative electrode terminal  7  extend from edge portions of the conductive plates  5  in a direction that intersects the stacking direction. Charging and discharging of the electricity-storage device  1  are carried out by the positive electrode terminal  6  and the negative electrode terminal  7   
     A plurality of flow passages  5   a  through which a coolant such as air is circulated is provided inside the conductive plate  5 . For example, the flow passages  5   a  extend along a direction that intersects (is perpendicular) to the stacking direction and the extension direction of the positive electrode terminal  6  and the negative electrode terminal  7 . The conductive plate  5  has a function as a heat dissipation plate for dissipating heat generated in the electricity-storage module  4  by circulating the coolant through the flow passages  5   a  in addition to a function as a connection member that electrically connects the electricity-storage modules  4  to each other. Note that, in the example illustrated in  FIG. 1 , an area of the conductive plate  5  when viewed from the stacking direction is smaller than an area of the electricity-storage module  4 . However, the area of the conductive plate  5  may be equal to the area of the electricity-storage module  4  or may be greater than the area of the electricity-storage module  4  from the viewpoints of an improvement of heat dissipation. 
     The constraining member  3  includes a pair of end plates  8  between which the module stacked body  2  is interposed in a stacking direction, and a fastening bolt  9  and a nut  10  which fasten the end plates  8 . Each of the end plates  8  is a rectangular metal plate having an area that is slightly larger than the areas of the electricity-storage module  4  and the conductive plate  5  when viewed from the stacking direction. A film F having electrical insulation property is provided on an inner surface of the end plate  8  (a surface on the module stacked body  2  side). The end plate  8  and the conductive plate  5  are insulated by the film F 
     An insertion hole  8   a  is provided in an edge portion of the end plate  8  at a position on an outer side in comparison to the module stacked body  2 . The fastening bolt  9  passes through the insertion hole  8   a  of one of the end plates  8  toward the insertion hole  8   a  of the other end plate  8 , and the nut  10  is screwed to a tip end portion of the fastening bolt  9  that protrudes from the insertion hole  8   a  of the other end plate  8 . According to this, the electricity-storage module  4  and the conductive plate  5  are sandwiched by the end plates  8  to form a unit as the module stacked body  2 , and a constraining load is applied to the module stacked body  2  in the stacking direction. 
     Next, a configuration of the electricity-storage module  4  will be described in detail.  FIG. 2  is a schematic cross-sectional view illustrating an internal configuration of the electricity-storage module illustrated in  FIG. 1 . As illustrated in  FIG. 2 , the electricity-storage module  4  includes an electrode stacked body (stacked body)  11 , and a sealing body  12  that is formed from a resin and seals the electrode stacked body  11 . The electrode stacked body  11  includes a plurality of electrodes (a plurality of bipolar electrodes  14 , a single negative terminal electrode (electrode)  18 , and a single positive terminal electrode  19 ) which are stacked in a stacking direction D (first direction) through a separator  13 . Here, the stacking direction D of the electrode stacked body  11  matches the stacking direction of the module stacked body  2 . The electrode stacked body  11  includes a side surface  1  la that extends in the stacking direction D. 
     The bipolar electrode  14  includes an electrode plate  15 , a positive electrode  16  provided on a first surface  15   a  of the electrode plate  15 , and a negative electrode  17  that is provided on a second surface  15   b  of the electrode plate  15  which is opposite to the first surface  15   a.  The positive electrode  16  is a positive electrode active material layer that is formed by coating a positive electrode active material on the electrode plate  15 . The negative electrode  17  is a negative electrode active material layer that is formed by coating a negative electrode active material on the electrode plate  15 . In the electrode stacked body  11 , the positive electrode  16  of one of the bipolar electrodes  14  faces the negative electrode  17  of another bipolar electrode  14  adjacent in the stacking direction D with the separator  13  interposed therebetween. In the electrode stacked body  11 , the negative electrode  17  of one of the bipolar electrodes  14  faces the positive electrode  16  of another bipolar electrode  14  adjacent with the separator  13  interposed therebetween in the stacking direction D. 
     The negative terminal electrode  18  includes the electrode plate  15  and the negative electrode  17  provided on the second surface  15   b  of the electrode plate  15 . The negative terminal electrode  18  is disposed at one end in the stacking direction D such that the second surface  15   b  is an inner side (central side with respect to the stacking direction D) of the electrode stacked body  11 . The negative electrode  17  of the negative terminal electrode  18  faces the positive electrode  16  of the bipolar electrode  14  at the one end in the stacking direction D through the separator  13 . The positive terminal electrode  19  includes the electrode plate  15  and the positive electrode  16  provided on the first surface  15   a  of the electrode plate  15 . The positive terminal electrode  19  is disposed at the other end in the stacking direction D such that the first surface  15   a  is an inner side of the electrode stacked body  11 . The positive electrode  16  of the positive terminal electrode  19  faces the negative electrode  17  of the bipolar electrode  14  at the other end in the stacking direction D through the separator  13 . 
     A conductive plate  5  is in contact with the first surface  15   a  of the electrode plate  15  of the negative terminal electrode  18 . In addition, another conductive plate  5  adjacent to the electricity-storage module  4  is in contact with the second surface  15   b  of the electrode plate  15  of the positive terminal electrode  19 . A constraining load applied from the constraining member  3  is applied to the electrode stacked body  11  from the negative terminal electrode  18  and the positive terminal electrode  19  through the conductive plates  5 . That is, the conductive plates  5  function also as a constraining member that applies the constraining load to the electrode stacked body  11  along the stacking direction D. 
     For example, the electrode plate  15  is formed from a metal such as nickel and a nickel plated steel plate. As an example, the electrode plate  15  is rectangular metal foil formed from nickel. An edge portion  15   c  of the electrode plate  15  (edge portion of the bipolar electrode  14 , the negative terminal electrode  18 , and the positive terminal electrode  19 ) has a rectangular frame shape, and is an uncoated region that is not coated with the positive electrode active material and the negative electrode active material. Examples of the positive electrode active material that constitutes the positive electrode  16  include nickel hydroxide. Examples of the negative electrode active material that constitutes the negative electrode  17  include a hydrogen occluding alloy. In this embodiment, a formation region of the negative electrode  17  on the second surface  15   b  of the electrode plate  15  is slightly greater than a formation region of the positive electrode  16  on the first surface  15   a  of the electrode plate  15 . 
     For example, the separator  13  is formed in a sheet shape. Examples of the separator  13  include a porous film formed from a polyolefin-based resin such as polyethylene (PE) and polypropylene (PP), woven or nonwoven fabric formed from polypropylene, methyl cellulose, and the like. In addition, the separator  13  may be reinforced with a vinylidene fluoride resin compound or the like. Note that, the separator  13  is not limited to the sheet shape, and a bag-shaped separator may be used. 
     The sealing body  12  is formed from an insulating resin in a rectangular tube shape as a whole. The sealing body  12  is provided to the side surface  11  a of the electrode stacked body  11  so as to surround the edge portions  15   c.  The sealing body  12  holds the edge portion  15   c  at the side surface  11   a.  The sealing body  12  includes a plurality of first resin portions (a plurality of first sealing portions)  21  which are joined (welded as an example (the same shall apply hereinafter)) to a plurality of the edge portions  15   c,  and a single second resin portion (second sealing portion)  22  that is joined to the first resin portions  21  so as to surround the first resin portions  21  from an outer side along the side surface  11   a.    
     The first resin portions  21  have a rectangular annular shape and are continuously provided over the entire periphery of the edge portions  15   c  when viewed from the stacking direction D. Each of the first resin portions  21  is air-tightly joined to the first surface  15   a  of the electrode plate  15 . For example, the first resin portion  21  is joined with ultrasonic waves or heat. The first resin portion  21  is a film having a predetermined thickness (a length in the stacking direction D). An end surface of the electrode plate  15  is exposed from the first resin portion  21 . In the first resin portion  21 , a part on an inner side is located between the edge portions  15   c  of the electrode plates  15  adjacent to each other in the stacking direction D, and a part on an outer side extends from the electrode plate  15  to the outside. The first resin portion  21  is buried in the second resin portion  22  at a part on the outer side. The first resin portions  21  adjacent to each other along the stacking direction D are spaced apart from each other. 
     The second resin portion  22  is provided on an outer side of the electrode stacked body  11  and the first resin portions  21 , and constitutes an outer wall (casing) of the electricity-storage module  4 . For example, the second resin portion  22  is formed by resin injection molding, and extends over the entire length of the electrode stacked body  11  along the stacking direction D. The second resin portion  22  has a tubular shape (annular shape) that extends with the stacking direction D set as an axial direction. For example, the second resin portion  22  is joined to outer surfaces of the first resin portions  21  with heat at the time of the injection molding. 
     The second resin portion  22  seals a portion between the bipolar electrodes  14  adjacent to each other along the stacking direction D, a portion between the negative terminal electrode  18  and the bipolar electrode  14  adjacent to each other along the stacking direction D, and a portion between the positive terminal electrode  19  and the bipolar electrode  14  adjacent to each other along the stacking direction D in combination with the first resin portions  21 . According to this, an inner space V that is air-tightly partitioned is formed between the bipolar electrodes  14 , between the negative terminal electrode  18  and the bipolar electrode  14 , and between the positive terminal electrode  19  and the bipolar electrode  14 . For example, the inner space V stores an electrolytic solution (not illustrated) composed of an aqueous alkali solution such as an aqueous solution of potassium hydroxide. The separator  13 , the positive electrode  16 , and the negative electrode  17  are impregnated with the electrolytic solution. 
     For example, the first resin portions  21  and the second resin portion  22  may be constituted with polypropylene (PP), polyphenylene sulfide (PPS), and modified polyphenylene ether (modified PPE) which are insulating resins. 
       FIG. 3  is a schematic cross-sectional view illustrating a joining interface between the electrode plate and the first resin portions. As illustrated in  FIG. 3 , a surface of the electrode plate  15  is roughened. Here, the entire surface of the electrode plate  15  including the first surface  15   a,  the second surface  15   b,  and an end surface as illustrated in  FIG. 2  is roughened. For example, the surface of the electrode plate  15  is roughened by forming a plurality of protrusions  15   p  through electroplating processing. In this manner, in a case where the electrode plate  15  is roughened, at the joining interface between the electrode plate  15  and the first resin portion  21 , the first resin portion  21  in a molten state enters a concave portion formed through the roughening, and an anchor effect is exhibited. According to this, a coupling force between the electrode plate  15  and the first resin portion  21  can be improved. At least, in a case where the edge portion  15   c  in the first surface  15   a  is roughened, an effect of an improvement in the coupling force is obtained. For example, the protrusions  15   p  have a shape that expands from a base end side to a tip end side. In this case, a cross-sectional shape between the protrusions  15   p  adjacent to each other becomes an under-cut shape, and the anchor effect is likely to occur. Note that,  FIG. 3  is a schematic view, and the shape, density, and the like of the protrusions  15   p  are not particularly limited. 
     Description will be given with reference to  FIG. 2  again. As illustrated in  FIG. 2 , the second resin portion  22  includes a first overlapping portion  22   a  that is provided on a third resin portion  23  so as to overlap the third resin portion (third sealing portion)  23  as one of the first resin portions  21  which is joined to the edge portion  15   c  of the negative terminal electrode  18  at one end side of the electrode stacked body  11  in the stacking direction D. The first overlapping portion  22   a  is formed in a rectangular annular shape and overlaps the entire periphery of an outer edge portion of the third resin portion  23  when viewed from the stacking direction D. The first overlapping portion  22   a  is air-tightly joined to an outer surface of the third resin portion  23 . 
     In addition, the second resin portion  22  includes a second overlapping portion  22   b  provided on a fourth resin portion  24  so as to overlap the fourth resin portion (fourth sealing portion)  24  as one of the first resin portions  21  which is joined to the edge portion  15   c  of the positive terminal electrode  19  at the other end side of the electrode stacked body  11  in the stacking direction D. The second overlapping portion  22   b  is formed in a rectangular annular shape and overlaps the entire periphery of an outer edge portion of the fourth resin portion  24  when viewed from the stacking direction D. The second overlapping portion  22   b  is air-tightly joined to an outer surface of the fourth resin portion  24 . 
     The thickness Ta of the first overlapping portion  22   a  along the stacking direction D is larger than the thickness Tb of the second overlapping portion  22   b  along the stacking direction D. According to this, the rigidity of the first overlapping portion  22   a  as a whole becomes greater than the rigidity of the second overlapping portion  22   b  as a whole, and thus the first overlapping portion  22   a  is less likely to be relatively deformed. As a result, a regulation portion  25  configured to regulate deformation of the third resin portion  23  along the stacking direction D is constituted in the first overlapping portion  22   a.  That is, the first overlapping portion  22   a  includes a portion in which the thickness Ta along the stacking direction D is larger than the thickness Tb of the second overlapping portion  22   b  as the regulation portion  25 . Here, it is assumed that the entirety of the first overlapping portion  22   a  has the same thickness, and is set as the regulation portion  25 . 
     Here, the thickness of the regulation portion  25  along the stacking direction D (that is, the thickness Ta of the first overlapping portion  22   a ) is two or more times the thickness T 21  of the first resin portion  21  along the stacking direction D. However, an outer edge  25   e  of the regulation portion  25  in the stacking direction D is located on a further inner side of the electrode stacked body  11  in comparison to an outer edge  5   e  of the conductive plate  5  in the stacking direction D. That is, the thickness of the regulation portion  25  is two or more times the thickness T 21  of the first resin portion  21  in a range in which the outer edge  25   e  of the regulation portion  25  is located on a further inner side of the electrode stacked body  11  in comparison to the outer edge  5   e  of the conductive plate  5 . Note that, here, the first overlapping portion  22   a  (that is, the regulation portion  25 ) does not overlap the electrode plate  15  when viewed from the stacking direction D. 
     As an example, the thickness Ta is equal to or greater than  300  pm and equal to or less than 3 mm When the thickness Ta is greater than 3 mm, there is a concern that the thickness Ta may be larger than the thickness of the conductive plate  5  along the stacking direction D. In this case, the following problems may occur. That is, electrical connection between the electricity-storage modules  4  through the conductive plate  5  may be difficult. Heat dissipation (cooling property) of the electricity-storage module  4  using the conductive plate  5  deteriorates. In addition, the size of the electricity-storage module  4  increases. Deterioration is promoted due to concentration of a load to the first resin portion  21  and the second resin portion  22  (a pressure is less likely to be uniformly received on a surface). In other words, when the thickness Ta is set to 3 mm or less, it is possible to suppress occurrence of the problems. 
     On the other hand, in a case where the thickness Ta is  300  pm or greater (two or more times the thickness Tb), positioning when providing the conductive plate  5  becomes easy. In addition, in this case, a pressure-resistant strength is sufficiently secured, and thus deformation can be reliably regulated. 
     Next, an example of a method for manufacturing the electricity-storage device  1  will be described. In this method, first, the electricity-storage module  4  is manufactured. A method for manufacturing the electricity-storage module  4  includes a primary molding process, a stacking process, a secondary molding process, and an injection process. In the primary molding process, a predetermined number of the bipolar electrodes  14 , the negative terminal electrode  18 , and the positive terminal electrode  19  are prepared, and the first resin portions  21  are joined to the first surfaces  15   a  of the edge portions  15   c  of the electrode plates  15 . 
     In the stacking process, the bipolar electrodes  14 , the negative terminal electrode  18 , and the positive terminal electrode  19  are stacked through the separator  13  in such a manner that each of the first resin portions  21  is disposed between the edge portions  15   c  of the electrode plates  15 , thereby forming the electrode stacked body  11 . In the secondary molding process, the electrode stacked body  11  is disposed in an injection molding mold (not illustrated), and a molten resin is injected into the mold, thereby forming the second resin portion  22  so as to surround the first resin portions  21 . According to this, the sealing body  12  is formed on the side surface  11   a  of the electrode stacked body  11 . In the injection process, after the secondary molding process, an electrolytic solution is injected into the inner space V between the bipolar electrodes  14  and  14 . According to this, the electricity-storage module  4  is obtained. 
     Then, the obtained electricity-storage module  4  and the conductive plates  5  are stacked to form the module stacked body  2 , and the electricity-storage device  1  is manufactured through a process of constraining the module stacked body  2  with the constraining member  3 , and the like. 
     Next, an operation and an effect of the electricity-storage module  4  will be described.  FIG. 4  is an enlarged cross-sectional view of a part of an electricity-storage module according to a comparative example.  FIG. 5  is a view for describing a problem that occurs in the electricity-storage module of the comparative example. In an example illustrated in  FIG. 4  and  FIG. 5 , a sealing body  12 A is used instead of the sealing body  12 . The sealing body  12 A includes a second resin portion  22 A instead of the second resin portion  22 . A first overlapping portion  22 Aa of the second resin portion  22 A is thinner than the first overlapping portion  22   a  of the second resin portion  22 , and the regulation portion  25  is not provided. 
     Therefore, when a load is applied to the electrode plate  15  of the negative terminal electrode  18  in accordance with an increase in an inner pressure, there is a concern that the first resin portion  21  joined to the electrode plate  15  may be deformed. In this case, a gap occurs between the first resin portion  21  and the electrode plate  15  (for example, as illustrated in  FIG. 5 , a gap W is formed between the electrode plate  15  and the first resin portion  21 ), and thus there is a concern that leakage of an electrolytic solution L may occur through the gap. In addition, when deformation of the first resin portion  21  increases, there is a possibility that breakage of the first resin portion  21  may occur. The leakage of the electrolytic solution L may occur due to an alkali creep phenomenon, particularly, on the negative terminal electrode  18  side. 
     In the electricity-storage module, due to a so-called alkali creep phenomenon, the electrolytic solution L may be transferred onto the electrode plate  15  of the negative terminal electrode  18 , passes through the gap W between the first resin portion  21  of the sealing body  12 A and the electrode plate  15 , and is seeped to the first surface  15   a  side of the electrode plate  15 . In  FIG. 4 , a movement route of the electrolytic solution L in the alkali creep phenomenon is indicated by an arrow A. The alkali creep phenomenon may occur during charging and discharging of the electricity-storage device, and during no load due to an electrochemical factor, a fluid phenomenon, or the like. The alkali creep phenomenon occurs due to existence of a negative electrode potential, moisture, and a passage of the electrolytic solution L. 
     In contrast, according to the electricity-storage module  4 , leakage or breakage of the first resin portion  21  caused by the alkali creep phenomenon is suppressed, and thus reliability can be improved. That is, in the electricity-storage module  4 , the sealing body  12  is provided in the electrode stacked body  11 . The sealing body  12  includes the first resin portions  21  which are joined to the edge portions  15   c  of the electrodes (the bipolar electrodes  14 , the negative terminal electrode  18 , and the positive terminal electrode  19 ), and the second resin portion  22  provided so as to surround the first resin portions  21 . On the other hand, the negative terminal electrode  18  is disposed at one end of the electrode stacked body  11 . In addition, the second resin portion  22  includes the first overlapping portion  22   a  provided on the third resin portion  23  so as to overlap the third resin portion  23  as one of the first resin portions  21  which is joined to the edge portion  15   c  of the negative terminal electrode  18 . In addition, the first overlapping portion  22   a  includes the regulation portion  25  configured to regulate deformation of the third resin portion  23 . According to this, at least, deformation of the first resin portions  21  and the like is suppressed on the negative terminal electrode  18  side, and thus the leakage or the breakage is suppressed. Accordingly, according to the electricity-storage module  4 , reliability is improved. 
     In addition, in the electricity-storage module  4 , the second resin portion  22  includes the second overlapping portion  22   b  provided on the fourth resin portion  24  so as to overlap the fourth resin portion  24  as one of the first resin portions  21  which is joined to the edge portion  15   c  of the positive terminal electrode  19  at the other end side of the electrode stacked body  11 . In addition, the first overlapping portion  22   a  includes a portion in which the thickness Ta along the stacking direction D is larger than the thickness Tb of the second overlapping portion  22   b  as the regulation portion  25 . According to this, reliability can be improved with a simple configuration. 
     In addition, the electricity-storage module  4  includes the conductive plate  5  that is disposed at the one end side of the electrode stacked body  11  and is configured to apply a constraining load to the electrode stacked body  11  along the stacking direction D. In addition, the thickness Ta of the regulation portion  25  along the stacking direction D is two or more times the thickness T 21  of the first resin portion  21  along the stacking direction D in a range in which the outer edge  25   e  of the regulation portion  25  in the stacking direction D is located on a further inner side of the electrode stacked body  11  in comparison to the outer edge  5   e  of the conductive plate  5 . According to this, it is possible to reliably improve reliability while avoiding an increase in size. 
     The embodiment relates to an embodiment of the electricity-storage module according to an aspect of the invention. Accordingly, the electricity-storage module according to the aspect of the invention is not limited to the above-described electricity-storage module  4 , and can be an electricity-storage module obtained by arbitrarily modifying the electricity-storage module  4  in a range not changing the gist of the appended claims Next, a modification example of the electricity-storage module  4  will be described. 
       FIG. 6  is a schematic cross-sectional view illustrating an internal configuration of the electricity-storage module according to this modification example As illustrated in  FIG. 6 , here, as a regulation portion  26 , the first overlapping portion  22   a  includes a portion that extends toward an inner side of the electrode stacked body  11  so as to further overlap the electrode plate  15  (edge portion  15   c ) of the negative terminal electrode  18  in addition to the first resin portion  21  when viewed from the stacking direction D. In addition, as the regulation portion  26 , the first overlapping portion  22   a  includes a portion that extends toward an inner side of the electrode stacked body  11  of the positive terminal electrode  19  so as to further overlap the electrode plate  15  (edge portion  15   c ) of the positive terminal electrode  19  in addition to the first resin portion  21  when viewed from the stacking direction D. According to the regulation portions  26 , deformation of the first resin portions  21  is also regulated with a simple configuration, and thus reliability can be improved. In addition, here, with regard to the second overlapping portion  22   b  on the positive terminal electrode  19  side, the regulation portion  26  configured to regulate deformation of the first resin portion  21  is provided, and thus reliability can be further improved. 
     In addition, configurations may be redundantly employed between the electricity-storage module  4  illustrated in  FIG. 2 , and the electricity-storage module  4  illustrated in  FIG. 6 . That is, in the electricity-storage module  4  illustrated in  FIG. 2 , the second overlapping portion  22   b  may also be provided with the regulation portion  25  as in the first overlapping portion  22   a.  In this case, the thickness Ta of the first overlapping portion  22   a  may be substantially the same as the thickness Tb of the second overlapping portion  22   b.    
     In addition, in the electricity-storage module  4  illustrated in  FIG. 2 , the first overlapping portion  22   a  and/or the second overlapping portion  22   b  may extend toward an inner side of the electrode stacked body  11  so as to further overlap the electrode plate  15  while maintaining the thickness. In this case, the first overlapping portion  22   a  has functions of the regulation portion  25  and the regulation portion  26 , and the second overlapping portion  22   b  has function of the regulation portion  26 . In addition, the thickness and an extension length of the second overlapping portion  22   b  may be set to have functions of the regulation portion  25  and the regulation portion  26 . 
     Here,  FIG. 7  is a schematic cross-sectional view illustrating an internal configuration of an electricity-storage module according to another modification example. In the electricity-storage module  4  illustrated in  FIG. 7 , the first overlapping portion  22   a  includes a first portion P 1 . In addition, the second overlapping portion  22   b  includes a second portion P 2 . The first portion P 1  and the second portion P 2  are formed in an annular shape when viewed from the stacking direction D (first direction). The first portion P 1  and the second portion P 2  are portions having a thickness equal to or larger than the thickness (a dimension in a direction intersecting the stacking direction D) of the second resin portion  22  on the side surface  11   a  that intersects the stacking direction D of the electrode stacked body  11 . 
       FIG. 8  is an enlarged view of a main portion illustrated in  FIG. 7 . As illustrated in  FIG. 8 , the first resin portion  21  includes an annular extension portion  21   p  that extends from the edge portion  15   c  of the electrode plate  15  of an electrode (here, the negative terminal electrode  18 ) to an outer side of the electrode when viewed from the stacking direction D. The extension portion  21   p  is a portion that overlaps a region R between an outer end surface  15   e  of the electrode plate  15  and an inner side surface  22   e  of the second resin portion  22  when viewed from the stacking direction D. The inner side surface  22   e  is a surface that faces the end surface  15   e.  The electrode plate  15  is not disposed in the region R. 
     The first portion P 1  is provided in an annular shape so as to cover the extension portion  21   p  when viewed from the stacking direction D. The thickness (a dimension along the stacking direction D) TP of the first portion P 1  is equal to or larger than the thickness TS of the second resin portion  22  on the side surface  11   a  of the electrode stacked body  11 . Here, the first portion P 1  is provided in a part of the first overlapping portion  22   a  (may be provided at the entirety thereof). Accordingly, a corner portion C is provided between a base portion of the first overlapping portion  22   a  and the first portion P 1 . According to this, a shortest distance from the region R to the outside may be a distance DP from the outer edge portion of the extension portion  21   p  to the corner portion C. In this case, the distance DP is equal to or larger than the thickness TS. For example, the thickness TP and the distance DP is equal to or greater than 300 μm and equal to or less than 3 mm Note that,  FIG. 8  and description of the first portion P 1  with reference to  FIG. 8  is also true of the second portion P 2 . The first portion P 1  and the second portion P 2  can function as the above-described regulation portion. 
     As described above, in the electricity-storage module  4  according to this example, the sealing body  12  is provided in the electrode stacked body  11 . The sealing body  12  includes the first resin portions  21  joined to the edge portions  15   c  of respective electrodes, and the second resin portion  22  provided so as to surround the first resin portions  21 . On the other hand, the negative terminal electrode  18  including the electrode plate  15  and the negative electrode  17  is disposed at one end of the electrode stacked body  11 . In addition, the second resin portion  22  includes the first overlapping portion  22   a  that is provided on the third resin portion  23  so as to overlap the third resin portion  23  as one of the first resin portions  21  which is joined to the edge portion  15   c  of the negative terminal electrode  18 . 
     In addition, the first overlapping portion  22   a  includes the first portion P 1  having the thickness TP equal to or larger than the thickness TS of the second resin portion  22  on the side surface  11   a  that intersects the stacking direction D of the electrode stacked body  11 . According to this, deformation of the sealing body  12  and the like is suppressed at least on the negative terminal electrode  18  side, and thus leakage or breakage is suppressed. Accordingly, according to the electricity-storage module  4  of this example, reliability is also improved. 
     In addition, in the electricity-storage module  4  according to this example, the second resin portion  22  includes the second overlapping portion  22   b  that is provided on the fourth resin portion  24  so as to overlap the fourth resin portion  24  as one of the first resin portions  21  which is joined to the edge portion  15   c  of the positive terminal electrode  19  on the other end side of the electrode stacked body  11 . The second overlapping portion  22   b  includes the second portion P 2  having a thickness equal to or larger than the thickness TS of the second resin portion  22  on the side surface  11   a  of the electrode stacked body  11  which intersects the stacking direction D. According to this, even on the positive terminal electrode  19  side, deformation of the sealing body  12  or the like is suppressed, and thus leakage or breakage is suppressed. Accordingly, according to the electricity-storage module  4  of this example, reliability is reliably improved. 
     Here, in an electricity-storage module, hydrogen is generated on the negative electrode at the first charging due to water in an electrolytic solution. In a case where the negative electrode includes a hydrogen occluding alloy, the hydrogen is occluded to the negative electrode. However, a hydrogen absorbing state is unstable at an inner pressure at the time of typical use, and thus the negative electrode ejects a constant amount of hydrogen. According to this, it enters a state in which hydrogen exists in an inner space. In the electricity-storage module, there is a demand for suppression of transmission of the hydrogen (hydrogen transmission) to the outside. 
     In the electricity-storage module  4  according to this example, the first resin portion  21  includes the annular extension portion  21   p  that extends from the edge portion  15   c  of an electrode to an outer side of the electrode when viewed from the stacking direction D. In addition, the first portion P 1  and the second portion P 2  are provided in an annular shape so as to cover the extension portion  21   p  when viewed from the stacking direction D. 
     According to this, in the region R corresponding to the extension portion  21   p,  an electrode is not interposed when viewed from the stacking direction D, and it is considered that hydrogen transmission along the stacking direction D is likely to occur. In contrast, in the electricity-storage module  4  of this example, the first portion P 1  and the second portion P 2  having a relatively large thickness are provided in the region R that overlaps the extension portion  21   p  when viewed from the stacking direction D. Accordingly, hydrogen transmission from the region R is suppressed, and thus reliability is more reliably improved. 
     INDUSTRIAL APPLICABILITY 
     It is possible to provide an electricity-storage module capable of improving reliability. 
     REFERENCE SIGNS LIST 
       4 : electricity-storage module,  5 : conductive plate (constraining member),  5   e:  outer edge,  11 : electrode stacked body (stacked body),  12 : sealing body,  15 : electrode plate,  15   c:  edge portion,  16 : positive electrode,  17 : negative electrode,  18 : negative terminal electrode,  19 : positive terminal electrode,  21 : first resin portion (first sealing portion),  22 : second resin portion (second sealing portion),  22   a:  first overlapping portion,  22   b:  second overlapping portion,  23 : third resin portion (third sealing portion),  24 : fourth resin portion (fourth sealing portion),  25 ,  26 : regulation portion, Ta, Tb, T 21 : thickness, D: stacking direction (first direction).