JP6946656B2 - Power storage module - Google Patents

Description

The present invention relates to a power storage module.

There is known a power storage module having a laminate in which a positive electrode is provided on one side of an electrode plate and a bipolar electrode is provided on the other side. For example, in Patent Document 1, in a bipolar battery (storage module) in which a laminated body is housed in a battery exterior material, a current collector (electrode plate) of a bipolar electrode is laminated via a seal layer. Further, in the laminated body, the seal layer is provided so as to surround the peripheral edge portion of the current collector, and the adjacent seal layers are further adhered to each other.

Japanese Unexamined Patent Publication No. 2005-190713

In the above-mentioned power storage module, improvement in airtightness is desired. Therefore, it is conceivable to provide a second seal layer (second seal portion) that surrounds the side surfaces of all the seal layers (first seal portion) and holds all the seal layers.

However, when the second seal portion surrounding all the first seal portions is formed by injection molding, the periphery of the first seal portion cannot be pressed by a mold or the like, so that the second seal portion cannot be pressed by injection molding. Due to the flow of the resin, the outer edge portion of the first seal portion arranged on the end side in the stacking direction of the laminated body may be rolled up. In such a case, the second seal portion cannot sufficiently surround the rolled-up first seal portion, or the rolled-up portion may not be filled with the resin of the second seal portion. A gap may be formed between the 1st seal portion and the 2nd seal portion, which may reduce the airtightness of the power storage module.

An object of the present invention is to provide a power storage module capable of suppressing a decrease in airtightness.

The power storage module according to the present invention is a power storage device having a bipolar electrode including a positive electrode layer provided on a first surface of an electrode plate and a negative electrode layer provided on a second surface opposite to the first surface. , The bipolar electrode group in which the bipolar electrodes are laminated via the separator, and the terminal in which the bipolar electrode group is arranged at both ends in the stacking direction via the separator, and the positive electrode layer or the negative electrode layer is provided only on the first surface of the electrode plate. The electrode plates are laminated at regular intervals by arranging the frame-shaped first seal portions having the electrodes and joined to the peripheral edge of the electrode plates in contact with each other in the stacking direction. The laminated body, the frame-shaped protrusion protruding from the peripheral edge of the second surface of the terminal electrode in the stacking direction, and the side surface of the laminated body are surrounded, and the first seal portion and the protruding portion are integrally joined. A second seal portion is provided, and the protruding portion includes a first structure formed by a part of the first seal portion, a second structure formed by a resin member different from the first seal portion, and a first. It is one of the third structures formed by the resin members fixed to the seal portions, and in the case of the first structure, the most of the first seal portions in the laminated body, which are arranged at both ends in the stacking direction of the laminated body. The thickness of the outer seal portion is larger than the thickness of the first seal portion arranged between the outermost seal portions in the stacking direction, and in the case of the second structure, the thickness of the resin member is larger than the thickness of the first seal portion. In the case of the third structure, the total value of the thickness of the resin member and the thickness of the first seal portion to which the resin member is fixed is larger than the thickness of the first seal portion.

The power storage module includes a frame-shaped protrusion that protrudes from the peripheral edge of the terminal electrode in the stacking direction, and the second seal portion integrally joins the first seal portion and the protrusion. Further, this protruding portion includes a part of the first seal portion (first structure), a resin member different from the first seal portion (second structure), and a resin member fixed to the first seal portion (third structure). ) Is formed by any of. In the case of the first structure, the thickness of the outermost seal portion of the laminated body is larger than the thickness of the first seal portion arranged between the outermost seal portions, and in the case of the second direction, the thickness of the resin member is the first seal. It is larger than the thickness of the portion, and in the case of the third structure, the total value of the thickness of the resin member and the thickness of the first seal portion to which the resin member is fixed is larger than the thickness of the first seal portion. With the protrusions formed in this way, it is possible to form portions having higher rigidity than other portions at both ends of the laminated body in the stacking direction. Therefore, even when the second seal portion surrounding the side surface of such a laminated body is formed by injection molding, for example, the seal portion holding the peripheral edge portion of the electrode plate arranged in the outermost layer may be rolled up. It is suppressed. Therefore, the protrusion and the first seal can be sufficiently connected by the second seal. As described above, it is possible to suppress a decrease in the airtightness of the power storage module.

In the power storage module according to the present invention, the thickness of the terminal electrode may be larger than the thickness of the electrode plate of the bipolar electrode. With this configuration, the rigidity of the terminal electrode, which is the electrode plate closest to the protruding portion, can be made higher than the rigidity of the electrode plate of the bipolar electrode. Therefore, when the second seal portion is formed by injection molding, the outermost layer is formed. It is further suppressed that the seal portion (first seal portion and the protruding portion) holding the peripheral edge portion of the arranged electrode plate is rolled up.

In the power storage module according to the present invention, the electrode plate is provided with a surface treatment portion for strengthening the bonding with the first seal portion, and in the electrode plate of the bipolar electrode, the surface treatment portion is the first surface and the second surface. It is provided on only one of the surfaces, and the one surface may be arranged in the same direction as each other in the stacking direction. With this configuration, the joint between the electrode plate and the first seal portion can be strengthened while minimizing the portion forming the surface treatment portion.

In the power storage module according to the present invention, in the terminal electrode, the surface treatment portion may be provided on only one of the first surface and the second surface. With this configuration, it is possible to further strengthen the connection between the terminal electrode and the protruding portion while minimizing the portion forming the surface treated portion.

In the power storage module according to the present invention, one side of the terminal electrode may be the second side. As described above, the frame-shaped protrusions protrude from the second surface of the terminal electrode in the stacking direction. As a result, the surface-treated portion can strengthen the bond between the terminal electrode (electrode plate) and the resin member.

In the power storage module according to the present invention, one surface of the terminal electrode and one surface of the electrode plate of the bipolar electrode may be arranged in the same direction in the stacking direction. In this case, since the surface treatment portion is provided on the surfaces of all the electrode plates of the laminated body arranged in the same direction, it is possible to suppress a decrease in the airtightness of the power storage module by a simple configuration.

According to the present invention, it is possible to suppress a decrease in airtightness due to curling up of the first seal portion.

FIG. 1 is a schematic cross-sectional view showing an embodiment of a power storage device including a power storage module. FIG. 2 is a schematic cross-sectional view showing the power storage module of FIG. FIG. 3 is an enlarged cross-sectional view of the peripheral edge of the terminal electrode and the peripheral edge of the bipolar electrode. FIG. 4 is an enlarged cross-sectional view of the surface of the current collector plate and the surface-treated portion. FIG. 5 is an enlarged cross-sectional view of the peripheral edge portion of the terminal electrode and the peripheral edge portion of the bipolar electrode according to the modified example. FIG. 6 is an enlarged cross-sectional view of the peripheral edge portion of the terminal electrode and the peripheral edge portion of the bipolar electrode according to the modified example. FIG. 7 is a schematic cross-sectional view showing a power storage module according to a modified example. FIG. 8 is a schematic cross-sectional view showing a power storage module according to a modified example. FIG. 9 is a schematic cross-sectional view showing a power storage module according to a modified example.

Hereinafter, the power storage module according to the embodiment of the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same elements or the corresponding elements may be designated by the same reference numerals, and duplicate description may be omitted. Further, in each figure, the Cartesian coordinate system S defined by the X-axis, the Y-axis, and the Z-axis may be shown.

The power storage device 10 shown in FIG. 1 is used as a battery for various vehicles such as forklifts, hybrid vehicles, and electric vehicles. The power storage module 12 is, for example, a bipolar battery. Examples of the power storage module 12 include a secondary battery such as a nickel hydrogen secondary battery and a lithium ion secondary battery, but may be an electric double layer capacitor. In the following description, a nickel-metal hydride secondary battery will be illustrated.

The plurality of power storage modules 12 are laminated via a conductor 14 such as a metal plate to form an array 11. The conductor 14 is one metal body arranged between the electricity storage modules 12 and 12 adjacent to each other, and is arranged in contact with both the electricity storage modules 12 and 12 adjacent to each other. The conductor 14 is formed of, for example, a metal material such as aluminum or copper. When the conductor 14 is viewed from the stacking direction (Z direction), the power storage module 12 and the conductor 14 have, for example, a rectangular shape. When viewed from the stacking direction, the conductor 14 is smaller than the power storage module 12, but may be the same as or larger than the power storage module 12. The conductor 14 is electrically connected to the adjacent power storage module 12. As a result, the plurality of power storage modules 12 are connected in series in the stacking direction.

The conductors 14 are also arranged on the outside of the power storage modules 12 located at both ends in the stacking direction of the power storage modules 12. That is, the conductors 14 are also arranged at both ends of the array 11 in the stacking direction. In the stacking direction, the positive electrode terminal 24 is connected to the conductor 14 located at one end, and the negative electrode terminal 26 is connected to the conductor 14 located at the other end. The positive electrode terminal 24 may be integrated with the conductor 14 to be connected. The negative electrode terminal 26 may be integrated with the conductor 14 to be connected. The positive electrode terminal 24 and the negative electrode terminal 26 extend in a direction (X direction) intersecting the stacking direction. The positive electrode terminal 24 and the negative electrode terminal 26 can be used to charge and discharge the power storage device 10.

The conductor 14 can also function as a heat sink for releasing the heat generated in the power storage module 12. By allowing a refrigerant such as air to pass through the plurality of through holes 14a provided inside the conductor 14, the heat generated in the power storage module 12 can be efficiently released to the outside. Each through hole 14a extends in a direction (Y direction) intersecting the stacking direction, for example.

The power storage device 10 may include a restraint member 15 that restrains the power storage modules 12 and the conductors 14 that are alternately stacked in the stacking direction. The restraint member 15 includes a pair of restraint plates 16 and 17 and a connecting member (bolt 18 and nut 20) for connecting the restraint plates 16 and 17 to each other. An insulating film 22 such as a resin film is arranged between the restraint plates 16 and 17 and the conductor 14. Each of the restraint plates 16 and 17 is made of, for example, a metal such as iron.

When viewed from the stacking direction, the restraint plates 16 and 17 and the insulating film 22 have, for example, a rectangular shape. The insulating film 22 is larger than the conductor 14, and the restraint plates 16 and 17 are larger than the power storage module 12. When viewed from the stacking direction, an insertion hole 16a through which the shaft portion of the bolt 18 is inserted is provided at a position outside the power storage module 12 at the edge portion of the restraint plate 16. Similarly, when viewed from the stacking direction, an insertion hole 17a through which the shaft portion of the bolt 18 is inserted is provided at a position outside the power storage module 12 at the edge portion of the restraint plate 17. When the restraint plates 16 and 17 have a rectangular shape when viewed from the stacking direction, the insertion holes 16a and the insertion holes 17a are located at the corners of the restraint plates 16 and 17.

One restraint plate 16 is abutted against the conductor 14 connected to the negative electrode terminal 26 via the insulating film 22, and the other restraint plate 17 has the insulating film 22 attached to the conductor 14 connected to the positive electrode terminal 24. It is struck through. For example, the bolt 18 is passed through the insertion hole 16a from one restraint plate 16 side toward the other restraint plate 17, and a nut 20 is screwed into the tip of the bolt 18 protruding from the other restraint plate 17. ing. As a result, the insulating film 22, the conductor 14, and the power storage module 12 are sandwiched and unitized, and a restraining load is applied in the stacking direction.

As shown in FIG. 2, the power storage module 12 includes a laminate 30 having a bipolar electrode group 33 in which a plurality of bipolar electrodes 32 are laminated. When viewed from the stacking direction of the bipolar electrode group 33 (the Z direction, which is the same as the stacking direction of the power storage module 12 and the conductor 14), the laminated body 30 has, for example, a rectangular shape. A separator 40 is arranged between the bipolar electrodes 32, 32 adjacent to each other. That is, the bipolar electrodes 32 of the bipolar electrode group 33 are laminated via the separator 40.

The bipolar electrode 32 includes an electrode plate 34, a positive electrode layer 36 provided on the first surface 34s of the electrode plate 34, and a negative electrode layer 38 provided on the second surface 34t opposite to the first surface 34s. include. In the laminated body 30, the positive electrode layer 36 of one bipolar electrode 32 faces the negative electrode layer 38 of one of the bipolar electrodes 32 adjacent to each other in the stacking direction with the separator 40 interposed therebetween, and the negative electrode layer 38 of one bipolar electrode 32 is It faces the positive electrode layer 36 of the other bipolar electrode 32 that is adjacent to each other in the stacking direction with the separator 40 in between.

In the laminated body 30, terminal electrodes 35 having a positive electrode layer 36 or a negative electrode layer 38 provided only on the first surface 34s of the electrode plate 34 are arranged at both ends in the stacking direction. Specifically, in the stacking direction, a terminal electrode 35 (negative electrode side terminal electrode) in which the negative electrode layer 38 is arranged on the inner side surface (first surface 34s) is arranged at one end of the laminated body 30, and at the other end. , The terminal electrode 35 (positive electrode side terminal electrode) in which the positive electrode layer 36 is arranged is arranged on the inner side surface (first surface 34s). The thickness D1 of the terminal electrode 35 is larger than the thickness D2 of the electrode plate 34 of the bipolar electrode 32. The thickness D1 of the terminal electrode 35 is, for example, 250 to 1000 μm. In this embodiment, the "thickness" means the length (dimensions) in the stacking direction (Z direction).

The negative electrode layer 38 of the negative electrode side terminal electrode faces the positive electrode layer 36 of the uppermost bipolar electrode 32 via the separator 40. The positive electrode layer 36 of the positive electrode side terminal electrode faces the negative electrode layer 38 of the lowermost bipolar electrode 32 via the separator 40. The electrode plates 34 of the terminal electrodes 35 are connected to adjacent conductors 14 (see FIG. 1).

In the laminated body 30, a frame-shaped first seal portion 52 that holds the peripheral edge portion 34a of the electrode plate 34 is joined to the peripheral edge portion 34a of the electrode plate 34. The first sealing portion 52 is provided in the laminated body 30 from one surface of the electrode plate 34 of the bipolar electrode 32 (the first surface 34s on which the positive electrode layer 36 is formed) to the end surface of the electrode plate 34 on the peripheral edge portion 34a. .. When viewed from the stacking direction, each of the first seal portions 52 is provided over the entire circumference of the peripheral edge portion 34a of each electrode plate 34. The first seal portions 52, 52 adjacent to each other are arranged in contact with each other in the stacking direction. The laminated body 30 is in a state in which the electrode plates 34 are laminated at regular intervals by arranging the first seal portions 52 in contact with each other in this way. The first seal portions 52 and 52 that are adjacent to each other are not joined at the portions that are in contact with each other, but are joined to each other by the second seal portion 54 that will be described later.

The first sealing portion 52 is welded on a surface extending outside the other surface (second surface 34t on which the negative electrode layer 38 is formed) of the electrode plate 34 of each bipolar electrode 32. As a result, the peripheral portion 34a of the electrode plate 34 of each bipolar electrode 32 is buried and held in the first seal portion 52. Similar to the peripheral edge portion 34a of the electrode plate 34 of each bipolar electrode 32, the peripheral edge portion 34a of the electrode plate 34 arranged at both ends of the laminated body 30 is also welded (fixed) to the first seal portion 52 or the first seal portion 52. ) Is held in a state of being buried in the resin member 56 (described later). As a result, an internal space V that is airtightly partitioned by the electrode plates 34, 34 and the first seal portion 52 is formed between the electrode plates 34, 34 that are adjacent to each other in the stacking direction. The internal space V contains an electrolytic solution (not shown) composed of an alkaline solution such as an aqueous potassium hydroxide solution.

The power storage module 12 includes frame-shaped protrusions 50 provided at both ends of the laminated body 30 in the stacking direction. The protruding portion 50 projects from the peripheral edge portion 35a of the terminal electrode 35 in the stacking direction. The protruding portion 50 is formed by a resin member 56 welded to the first sealing portion 52. The case where the protruding portion 50 is formed by the resin member 56 welded to the first sealing portion 52 is referred to as a "third structure". The "first structure" and the "second structure" will be described later.

The resin member 56 is arranged so as to overlap the first seal portion 52 when viewed from the stacking direction, and is welded to the first seal portion at a portion in contact with the first seal portion 52. However, the resin member 56 and the first seal portion 52 are not limited to the configuration in which they are welded to each other, and may be adhered to each other, for example. The resin member 56 is provided from one surface of the terminal electrode 35 (the first surface 34s for the positive electrode side terminal electrode and the second surface for the negative electrode side terminal electrode) to the end surface of the electrode plate 34 at the peripheral edge portion 35a. The total value D5 of the thickness D4 of the resin member 56 arranged at the other end of the laminate and the thickness D3 of the first seal portion 52 to which the resin member 56 is welded is larger than the thickness D3 of the first seal portion 52. Further, the total value D51 of the thickness D41 of the resin member 56 arranged at one end of the laminated body and the thickness D3 of the first seal portion 52 to which the resin member 56 is welded is larger than the thickness D3 of the first seal portion 52. .. Each of the total values D5 and D51 is, for example, 1.5 to 2.0 times the thickness D3 of the first seal portion 52. Each of the thicknesses D4 and D41 of the resin member 56 is, for example, 100 to 500 μm, and each of the total values D5 and D51 is, for example, 300 to 1000 μm.

The power storage module 12 includes a second seal portion that holds the laminated body 30 and the resin member 56 on the side surface 30a of the laminated body 30 extending in the stacking direction. The second seal portion 54 is configured to surround the side surface 30a of the laminated body 30. The side surface 54a of the second seal portion 54 has, for example, a rectangular shape when viewed from the stacking direction. In this case, the side surface 54a is composed of four rectangular surfaces.

The second seal portion 54 is a tubular portion extending over the entire length of the laminated body 30 in the stacking direction. The second seal portion 54 covers the outer surface of the first seal portion 52 and the resin member 56 on the inner surface extending in the stacking direction of the bipolar electrode 32. The second seal portion 54 is integrally formed with the first seal portion 52 and the resin member 56 by injection molding.

The electrode plate 34 is, for example, a rectangular metal leaf made of nickel. The peripheral edge portion 34a of the electrode plate 34 is an uncoated region in which the positive electrode active material and the negative electrode active material are not coated, and the uncoated region is a region buried and held in the first seal portion 52. ing. Examples of the positive electrode active material constituting the positive electrode layer 36 include nickel hydroxide. Examples of the negative electrode active material constituting the negative electrode layer 38 include a hydrogen storage alloy. The formation region of the negative electrode layer 38 on the second surface 34t of the electrode plate 34 is slightly larger than the formation region of the positive electrode layer 36 on the first surface 34s of the electrode plate 34. The electrode plate 34 may be formed of Ni-plated iron foil or a conductive resin.

The separator 40 is formed in a sheet shape, for example. Examples of the material forming the separator 40 include a porous film made of a polyolefin resin such as polyethylene (PE) and polypropylene (PP), a woven fabric made of polypropylene and the like, and a non-woven fabric. Further, the separator 40 may be reinforced with a vinylidene fluoride resin compound or the like.

The first seal portion 52, the second seal portion 54, and the resin member 56 are formed of, for example, an insulating resin. Examples of the resin material constituting each of the first seal portion 52, the second seal portion 54, and the resin member 56 include polypropylene (PP), polyphenylene sulfide (PPS), modified polyphenylene ether (modified PPE), and the like. Is done.

As shown in FIG. 3, the electrode plate 34 has a surface treatment portion 60 that strengthens the bonding with the first seal portion 52. In the electrode plate 34 of the bipolar electrode 32, the surface treatment portion 60 is provided only on one surface (first surface 34s). In the terminal electrode 35, the surface treatment portion 60 is provided only on one surface (the first surface 34s of the positive electrode side terminal electrode and the second surface 34t of the negative electrode side terminal electrode). One surface of the terminal electrode 35 and one surface of the electrode plate 34 of the bipolar electrode 32 are arranged in the same direction as each other in the stacking direction. Therefore, the surface treatment unit 60 is provided on the surfaces of all the electrode plates 34 of the laminated body 30 arranged in the same direction. The surface treatment portion 60 is formed in the entire region of one surface of all the electrode plates 34 of the laminated body 30. However, the surface treatment portion 60 may be formed in a region where either one of the frame-shaped first seal portion 52 and the frame-shaped resin member 56 is arranged. The surface treatment unit 60 can be formed by an electroplating layer obtained by electroplating the electrode plate 34.

An example of the electrolytic plating treatment will be described with reference to FIG. The electrolytic plating layer is a roughened plating layer formed on the surface of the electrolytic foil constituting the electrode plate 34. The electrolytic foil is obtained, for example, by immersing the drum and the anode in an electrolytic solution containing nickel cations and allowing a predetermined current to flow between the drum and the anode to deposit nickel on the surface of the drum. When nickel is deposited on the drum surface, a fine convex portion 34d is formed on the surface of the electrolytic foil opposite to the drum.

The electroplating layer is obtained by depositing nickel on the surface of the electrolytic foil on the drum until it has a certain thickness. When nickel is deposited on the surface of the electrolytic foil on the drum, nickel is deposited on the convex portion 34d of the electrolytic foil. Specifically, current concentration is generated in the convex portion 34d, and nickel is selectively deposited so that the convex portion 34d is the base end 62. The surface treatment portion 60 is formed by the plurality of protrusions 61 grown in this way. The above process is an electrolytic plating process.

The surface-treated portion 60 shown in FIG. 4 has a plurality of protrusions 61 protruding from one surface in the stacking direction by electroplating. Each protrusion 61 reaches the tip along the stacking direction with the convex portion 34d as the base end. The protrusions 61 are arranged along the directions intersecting the stacking directions (X direction and Y direction).

The protrusion 61 contains a plurality of substantially spherical precipitated metals (impartments) formed by electroplating. In the protrusion 61, the deposited metals overlap each other, so that the base end 62 (length (dimension) in the direction intersecting the stacking direction) of the protrusion 61 is larger than the width of the protrusion 61 at the base end 62. 64 is formed. That is, the protrusion 61 has a shape that becomes thicker from the base end 62 side toward the tip end 63 side. The position of the enlarged portion 64 on the protrusion 61 does not necessarily have to be the tip 63, but is located at least on the tip 63 side of the base end 62. The position of the enlarged portion 64 on the protrusion 61 may be different for each protrusion 61 depending on the overlapping mode of the deposited metal.

A part 52a of the first seal portion 52 is interposed between the protrusions 61 and 61 adjacent to each other. Specifically, the first seal portion 52 formed of the resin is molded so that a part 52a of the first seal portion 52 is interposed between the protrusions 61 at the time of molding. As a result, the protrusions 61 and 61 adjacent to each other restrict the movement of a part 52a of the intervening first seal portion 52 in the direction away from the base end 62. In other words, the cross-sectional shape between the protrusions 61 and 61 adjacent to each other is an undercut shape that exerts an anchor effect.

In the power storage module 12 described above, as shown in FIG. 2, the thickness D4 of the resin member 56 arranged at the other end of the laminated body 30 and the thickness D3 of the first seal portion 52 to which the resin member 56 is welded The total value D5 is larger than the thickness D3 of the first seal portion 52. Further, the total value D51 of the thickness D41 of the resin member 56 arranged at one end of the laminated body 30 and the thickness D3 of the first seal portion 52 to which the resin member 56 is welded is larger than the thickness D3 of the first seal portion 52. .. With the protruding portion 50 formed in this way, it is possible to form portions having higher rigidity than other portions at both ends of the laminated body 30 in the stacking direction. Therefore, even when the second seal portion 54 surrounding the side surface 30a of the laminated body 30 is formed by injection molding, for example, the peripheral portion 34a of the electrode plate 34 (termination electrode 35) arranged in the outermost layer is formed. It is suppressed that the seal portion (the first seal portion 52 and the resin member 56) holding the seal portion (the first seal portion 52 and the resin member 56) is rolled up. Therefore, the protrusion 50 and the first seal 52 can be sufficiently connected to each other by the second seal 54. As described above, it is possible to suppress a decrease in the airtightness of the power storage module 12.

Further, in the power storage module 12, the thickness D1 of the terminal electrode 35 is larger than the thickness D2 of the electrode plate 34 of the bipolar electrode 32. With this configuration, the rigidity of the terminal electrode 35, which is the electrode plate 34 closest to the protruding portion 50, can be made higher than the rigidity of the electrode plate of the bipolar electrode 32. Therefore, when the second seal portion 54 is formed by injection molding. In addition, the first seal portion 52 and the resin member 56 holding the peripheral edge portion 34a of the terminal electrode 35 are further suppressed from being rolled up.

As shown in FIG. 3, in the power storage module 12, the electrode plate 34 is provided with a surface treatment portion 60 for strengthening the bonding with the first seal portion 52, and the surface of the electrode plate 34 of the bipolar electrode 32 is provided. The processing unit 60 is provided on only one of the first surface 34s and the second surface 34t, and the one surfaces are arranged in the same direction as each other in the stacking direction. With this configuration, the joint between the electrode plate 34 and the first seal portion 52 can be strengthened while minimizing the portion forming the surface treatment portion 60. Further, since the surface treatment portion 60 is formed in the entire region on one surface, the bonding between the electrode plate 34 and the positive electrode active material or the negative electrode active material can be strengthened.

In the terminal electrode 35 of the power storage module 12, the surface treatment unit 60 is provided on only one of the first surface 34s and the second surface 34t. With this configuration, the joint between the terminal electrode 35 and the protruding portion 50 can be strengthened while minimizing the portion forming the surface treatment portion 60.

Further, as shown in FIG. 3, in the power storage module 12, one surface of the terminal electrode 35 and one surface of the electrode plate 34 of the bipolar electrode 32 are arranged in the same direction in the stacking direction. With this configuration, since the surface treatment unit 60 is provided on the surfaces of all the electrode plates 34 of the laminated body 30 arranged in the same direction, it is possible to suppress a decrease in the airtightness of the power storage module 12 with a simple configuration. ..

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment.

In the above embodiment, all the electrode plates 34 of the laminated body 30 have been described by exemplifying a configuration in which the surface treatment portion 60 is provided on one surface arranged in the same direction as each other, as shown in FIG. In addition, the electrode plate 34 of the laminated body 30 may include an electrode plate 34A having a surface treatment portion 60 provided on one surface arranged in a direction different from that of the other electrode plates 34. In the power storage module 12A shown in FIG. 5, in the terminal electrode 35, the surface treatment unit 60 has one surface facing outward in the stacking direction of the laminated body 30 (second surface 34t on each of the positive electrode side terminal electrode and the negative electrode side terminal electrode). ). In other words, the end electrode 35 may be provided with the surface treatment portion 60 on one surface arranged in different directions (opposite directions).

In the power storage module 12A, one side of each of the terminal electrodes 35 is a second side 34t. As described above, the frame-shaped protrusion 50 protrudes from the second surface 34t of the terminal electrode 35 in the stacking direction. That is, the surface treatment portion 60 is provided on one surface of each of the terminal electrodes 35 on the side where the resin member 56 is arranged. As a result, the surface treatment portion 60 can strengthen the bond between the terminal electrode 35 (electrode plates 34, 34A) and the resin member 56.

Further, in the above-described embodiment and the modified example, the configuration in which the surface treatment portion 60 is provided on only one surface of all the electrode plates 34 of the laminated body 30 has been described as an example, but the electrode plates 34 of the laminated body 30 have been described. An electrode plate 34B having surface treatment portions 60 on both sides may be included in a part of the electrode plate 34B. In the power storage module 12B shown in FIG. 6, the end electrode 35 arranged at one end of the laminated body 30 and the electrode plates 34 of all the bipolar electrodes 32 are provided with the surface treatment portion 60 on only one surface. In the terminal electrode 35 arranged at the other end of the laminated body 30, surface treatment portions 60 are provided on both sides. According to the power storage module 12B, the surface treatment unit 60 can strengthen the bonding between the terminal electrode 35 and the resin member 56 and the bonding between the terminal electrode 35 and the first seal portion 52. Therefore, the decrease in airtightness of the power storage module 12B can be further suppressed.

Further, in the above embodiment and the modified example, the frame-shaped protrusions 50 provided at both ends of the laminated body 30 are formed by the resin member 56 welded to the first seal portion 52, which is the "third structure". However, as shown in FIG. 7, the protruding portion may be a protruding portion 50C formed by a resin member 56C different from the first sealing portion 52 (second structure).

In the power storage module 12C shown in FIG. 7, the thickness D6 of the resin member 56C is different from the thickness D4 of the resin member 56. Further, the resin member 56C is the same as the resin member 56 in other configurations. However, unlike the above embodiment, the resin member 56C may not be welded to the first seal portion 52, or may be welded to the first seal portion 52. The thickness D6 of the resin member 56C is larger than the thickness D3 of the first seal portion 52. The thickness D6 of the resin member 56C is, for example, 1.5 to 2.0 times the thickness D3 of the first seal portion 52. The thickness D6 of the resin member 56C is, for example, 300 to 1000 μm.

In such a power storage module 12C, the thickness D6 of the resin member 56C is larger than the thickness D3 of the first seal portion 52. With the protruding portion 50C formed in this way, it is possible to form portions having higher rigidity than other portions at both ends of the laminated body 30 in the stacking direction. Therefore, even with this configuration, it is possible to suppress a decrease in the airtightness of the power storage module 12C.

Further, in the power storage module 12D shown in FIG. 8, a protruding portion 50 is provided at one end of the laminated body 30 in the stacking direction, and a protruding portion 50C is provided at the other end. As described above, the power storage module may include the protrusion 50 formed by the third structure and the protrusion 50C formed by the second structure. Protrusions may be formed at one end and the other end of the laminated body 30 by different structures.

Further, in the power storage module 12E shown in FIG. 9, the peripheral edge portion 34a of the electrode plate 34 of the bipolar electrode 32 is arranged in the first seal portion 52. As described above, the first sealing portion 52 may be provided from each of the first surface 34s and the second surface 34t of the electrode plate 34 of the bipolar electrode 32 to the end surface of the electrode plate 34 at the peripheral edge portion 34a. At this time, the power storage module 12E includes a protruding portion 50E, and the second seal portion 54 integrally joins the first seal portion 52. The protruding portion 50E is formed by a part of the outermost sealing portion 52E, which is the first sealing portion 52 arranged at both ends of the laminated body 30 in the stacking direction (first structure). The thickness D7 of the outermost seal portion 52E is larger than the thickness D3 of the first seal portion 52 arranged inside the outermost seal portion 52E in the stacking direction. The thickness D7 of the outermost seal portion 52E is, for example, 1.5 to 2.0 times the thickness D3 of the first seal portion 52 arranged inside the outermost seal portion 52E in the stacking direction. The thickness D7 of the outermost sealing portion 52E is, for example, 300 to 1000 μm.

In such a power storage module 12E, the thickness D7 of the outermost seal portions 52E arranged at both ends of the laminated body 30 in the stacking direction is the thickness D7 of the first seal portion 52 arranged between the outermost seal portions 52E in the stacking direction. It is larger than the thickness D3. With the protruding portion 50E formed in this way, it is possible to form portions having higher rigidity than other portions at both ends of the laminated body 30 in the stacking direction. Further, the protrusion 50E can be formed only by forming the thickness D7 of the outermost seal portion 52E of the first seal portion 52 to be larger than the thickness D3 of the other first seal portion 52. Therefore, the decrease in airtightness of the power storage module 12E can be suppressed by a simple configuration.

Further, in the above-described embodiment and modified example, the structure formed by the electrolytic plating layer (roughened plating layer) obtained by the electrolytic plating treatment on the electrode plate 34 as the surface treatment portion 60 has been described as an example. The processing unit 60 may be formed by etching the electrode plate 34.

Further, the electrode plate 34 does not have to have the surface treatment portion 60. The electrode plate 34 and the first seal portion 52, the resin member 56, or the resin member 56C may be adhered to each other by, for example, an adhesive.

Further, in the above-described embodiment or modified example, the power storage device 10 including the power storage module has been described with reference to an example of a nickel-metal hydride secondary battery, but a lithium ion secondary battery may also be used. In this case, the positive electrode active material is, for example, a composite oxide, metallic lithium, sulfur or the like. The negative electrode active material is, for example, graphite, highly oriented graphite, mesocarbon microbeads, carbon such as hard carbon or soft carbon, alkali metals such as lithium and sodium, metal compounds, SiOx (0.5 ≦ x ≦ 1.5). Such as metal oxides, boron-added carbon, and the like.

12, 12A, 12B, 12C, 12D, 12E ... Power storage module, 30 ... Laminate, 30a ... Side surface, 32 ... Bipolar electrode, 33 ... Bipolar electrode group, 34, 34B ... Electrode plate, 34a ... Peripheral part, 34s ... First 1st surface, 34t ... 2nd surface, 35 ... Terminal electrode, 36 ... Positive electrode layer, 38 ... Negative electrode layer, 40 ... Separator, 50, 50C, 50E ... Protruding part, 52 ... 1st sealing part, 52E ... Outermost sealing part , 54 ... Second seal portion, 56, 56C ... Resin member, 60 ... Surface treatment portion, D1, D2, D3, D4, D41, D6, D7 ... Thickness, D5, D51 ... Total value.

Claims (7)

A bipolar electrode having a positive electrode layer provided on the first surface of an electrode plate having a first surface and a second surface opposite to the first surface and a negative electrode layer provided on the second surface is provided in one direction. A terminal electrode in which a positive electrode layer or a negative electrode layer is provided only on one of the laminated bipolar electrode group and the first surface and the two surfaces of the electrode plate, and a negative electrode layer is provided only on the second surface of the electrode plate. The bipolar electrode group has a first terminal electrode provided with the above and a second terminal electrode provided with a positive electrode layer only on the first surface of the electrode plate, and the bipolar electrode group stacks the first surface in a stacking direction. The bipolar electrode in a state where one side and the second surface are directed to the other side in the stacking direction is laminated via a separator, and the first terminal electrode is in a state where the first surface is directed to the one side. The second terminal electrode is arranged at one end of the bipolar electrode group via a separator, and the second terminal electrode is the other end of the bipolar electrode group with the second surface facing the other side. The electrode plates are laminated at regular intervals by arranging the first seal portions in the shape of a frame, which are arranged in the portions via a separator and are joined to the peripheral edge portion of the electrode plates, in a state of being in contact with each other in the lamination direction. The laminated body that is in the state of being
A frame-shaped first protruding portion protruding from the peripheral edge portion of the first surface of the first terminal electrode to the one side.
A frame-shaped second protruding portion projecting from the peripheral edge portion of the second surface of the second terminal electrode to the other side,
A second seal portion that surrounds the side surface of the laminate and integrally joins the first seal portion, the first protrusion portion, and the second protrusion portion is provided.
Said first protrusion and said second protrusion, the second structure being formed by a different resin member from the first structure or the first sealing portion is formed by a portion of said first sealing portion can be,
In the case of the first structure, the thickness of the outermost sealing portions arranged at both ends of the laminated body in the laminating direction of the first sealing portion in the laminated body is the thickness of the outermost sealing portion in the laminating direction. It is larger than the thickness of the first seal portion arranged between them.
For the second structure, the thickness of the resin member, the not larger than the first seal portion of the thickness, a charge reservoir module. The power storage module according to claim 1, wherein the thickness of the electrode plate of the first terminal electrode and the second terminal electrode is larger than the thickness of the electrode plate of the bipolar electrode. The electrode plate is a metal foil and has a surface-treated portion that strengthens the bond with the first seal portion.
The power storage according to claim 1 or 2, wherein in the electrode plates of all the bipolar electrodes, the surface treatment portion is provided only on the first surface or is provided only on the second surface. module. In the electrode plate of the first terminal electrode, the surface treatment portion is provided on only one of the first surface and the second surface.
The power storage module according to claim 3, wherein in the electrode plate of the second terminal electrode, the surface treatment portion is provided on only one of the first surface and the second surface. In the electrode plate of the first terminal electrode, the surface treatment portion is provided only on the first surface, and in the electrode plate of the second terminal electrode, the surface treatment portion is provided only on the second surface. its dependent, power storage module according to claim 4. In the electrode plates of the bipolar electrode, the first terminal electrode, and the second terminal electrode, the surface treatment portions are all provided on the first surface, or all are provided on the second surface. , The power storage module according to claim 4. In the electrode plate of the first terminal electrode, the surface treatment portion is provided on at least the first surface, and in the electrode plate of the second terminal electrode, the surface treatment portion is provided on at least the second surface. The power storage module according to claim 3.

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