JP2019067615A - Nickel hydrogen secondary battery - Google Patents

Abstract

To provide a nickel hydrogen secondary battery capable of preventing liquid shortage of an electrolyte.SOLUTION: A nickel hydrogen secondary battery 2 comprises: an electrode laminate 13 formed by laminating a plurality of bipolar electrodes 11; and a primary seal member 20 surrounding the electrode laminate 13. The bipolar electrode 11 includes: a positive electrode 16 formed onto an upper surface 15a of a nickel foil 15; and a negative electrode 17 formed onto a lower surface 15b of the nickel foil 15. In the undermost layer of the electrode laminate 13, a positive electrode side termination electrode 18 to which the positive electrode 16 is formed onto the upper surface 15a of the nickel foil 15 is arranged. In the uppermost layer of the electrode laminate 13, a negative electrode side termination electrode 19 to which the negative electrode 17 is formed in the lower surface 15b of the nickel foil 15 is arranged. An alkaline electrolyte F is implanted into an inner space V of the electrode laminate 13, and a liquid accumulation part 22 accumulating the electrolyte F and a communication part 23 communicating the inner space V positioned at a lower end of a lamination direction of the electrode laminate 13 and the liquid accumulation part 22 are provided in the primary seal member 20.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a nickel hydrogen secondary battery.

  Patent Document 1 describes a bipolar battery. The bipolar battery described in Patent Document 1 includes a plurality of bipolar electrodes in which a positive electrode is provided on one surface of a current collector and a negative electrode is provided on the other surface of the current collector, and is interposed between the positive electrode and the negative electrode. And an electrolyte that holds the solution. The positive electrode is provided on one side of the current collector located at one end of the bipolar battery, and the negative electrode is provided on one side of the current collector located at the other end of the bipolar battery. In addition, the bipolar battery has an absorption layer for absorbing the electrolytic solution provided between the current collectors so as to surround the periphery of the unit cell constituted by the positive electrode, the negative electrode and the electrolyte. Thereby, the leak of the electrolyte solution from a cell can be prevented.

JP 2005-317380 A

  However, when the bipolar battery as in the prior art is applied to a nickel hydrogen secondary battery, the following problems exist. That is, in the nickel-hydrogen secondary battery, a phenomenon in which the alkaline electrolytic solution creeps up the surface of the metal foil (current collector), a so-called alkaline creep phenomenon occurs. The alkaline creep phenomenon causes the electrolyte to move along the surface of the metal foil, and eventually leaks out from the minute gap between the metal foil and the seal member. As a result, the electrolytic solution may dry up and the output of the battery may be reduced.

  An object of the present invention is to provide a nickel-hydrogen secondary battery capable of preventing the liquid withering of an electrolytic solution.

  One embodiment of the present invention is a nickel-hydrogen secondary battery including an electrode stack body in which a plurality of bipolar electrodes are stacked via a separator, and a seal member arranged to surround the electrode stack body. Has a current collector containing nickel, a positive electrode formed on one side of the current collector, and a negative electrode formed on the other side of the current collector. The positive electrode side end electrode having the positive electrode formed on one side of the current collector is disposed to face the bipolar electrode with the separator interposed therebetween, and on the other side of the current collector on the other outermost layer of the electrode laminate. The negative electrode side end electrode on which the negative electrode is formed is disposed to face the bipolar electrode with the separator interposed therebetween, and the current collector, the positive electrode, and the negative electrode are disposed between the current collectors adjacent in the stacking direction in the electrode stack. , Separators and seal members A defined internal space is disposed, an alkaline electrolyte is injected into the internal space, and the seal member includes a liquid reservoir for storing the electrolytic solution, and a lamination direction of the electrode stack. It is characterized in that a communication portion is provided which causes one of the two internal spaces located at both ends to communicate with the liquid reservoir.

  As described above, in the seal member, the liquid reservoir portion for storing the alkaline electrolyte and the communication portion for communicating the fluid reservoir portion with either one of the two internal spaces located at both ends in the stacking direction of the electrode stack. And are provided. For this reason, the electrolyte injected into the internal space creeps up on the surface of the current collector due to the creep phenomenon (alkali creep phenomenon) of the alkaline electrolyte and leaks out from the minute gap between the current collector and the seal member. Therefore, even if the amount of the electrolyte present in one of the two inner spaces (one of the inner spaces) located at both ends in the stacking direction of the electrode stack decreases, the electrolyte stored in the liquid reservoir continues to communicate. Supply to one of the interior spaces. That is, the electrolyte solution is replenished from the liquid reservoir to the one internal space by an amount corresponding to the disappearance of the electrolyte existing in the one internal space due to the alkaline creep phenomenon. Thereby, the liquid withering of the electrolytic solution is prevented.

  The seal member includes a plurality of first seal frames for holding current collectors of bipolar electrodes, a second seal frame for holding current collectors of positive electrode side end electrodes, and a current collector of negative electrode side end electrodes. 3 seal frame, and at least one fourth seal frame disposed between the first seal frames adjacent in the stacking direction of the electrode stack, and disposed between the first seal frame and the second seal frame A fifth seal frame, and a sixth seal frame disposed between the first seal frame and the third seal frame, the first seal frame, the fourth seal frame, the fifth seal frame, and the sixth seal frame Are provided with liquid reservoir holes penetrating in the laminating direction of the electrode laminate and forming a part of the liquid reservoir, and the communicating portion is provided in the fifth seal frame or the sixth seal frame, It may be connected with the reservoir hole. Thus, the seal member includes a first seal frame having a liquid storage hole, a second seal frame, a third seal frame, a fourth seal frame having a liquid storage hole, and a fifth seal frame having a liquid storage hole. And a sixth seal frame having a liquid reservoir hole. The communication portion is provided to the fifth seal frame or the sixth seal frame. Thus, the seal member having the liquid reservoir and the communication portion can be easily formed.

  The communication portion may be provided in the fifth seal frame and connected to the liquid reservoir hole. When a current flows in the nickel-hydrogen secondary battery, the positively charged alkaline electrolyte creeps up on the surface of the current collector due to the alkaline creep phenomenon, so the electrolyte from the positive side termination electrode to the negative side termination electrode Is more likely to leak. For this reason, the electrolyte solution existing in the internal space corresponding to the positive electrode side termination electrode is easily eliminated. Therefore, by providing a communication part in the fifth seal frame disposed between the first seal frame for holding the current collector of the bipolar electrode and the second seal frame for holding the current collector of the positive electrode side end electrode, The electrolytic solution is replenished from the liquid reservoir to the internal space corresponding to the positive electrode side end electrode. Thereby, the liquid withering of the electrolytic solution in the internal space corresponding to the positive electrode side terminal electrode is reliably prevented.

  The positive electrode side end electrode may be disposed in the lowermost layer of the electrode stack, and the second seal frame may be disposed in the lowermost layer of the sealing member. In such a configuration, when the amount of the electrolyte present in the internal space corresponding to the positive electrode side end electrode decreases due to the alkaline creep phenomenon, the electrolyte is supplied from the liquid reservoir to the internal space corresponding to the positive electrode side terminal electrode by gravity. . Therefore, replenishment of the electrolytic solution to the internal space corresponding to the positive electrode side end electrode is performed simply and reliably.

  According to the present invention, it is possible to prevent the liquid withering of the electrolytic solution.

It is a schematic sectional drawing which shows the electrical storage apparatus provided with the nickel hydride secondary battery which concerns on one Embodiment of this invention. It is a schematic sectional drawing of the nickel-hydrogen secondary battery shown by FIG. It is a disassembled perspective view of the electrode laminated body and primary seal member which were shown by FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic cross-sectional view showing a power storage device provided with a nickel-hydrogen secondary battery according to an embodiment of the present invention. In FIG. 1, power storage device 1 is used as a battery of a vehicle such as, for example, a forklift, a hybrid car, and an electric car. The storage device 1 includes a nickel-hydrogen secondary battery 2 as a plurality (three in this case) of storage modules.

  The plurality of nickel-hydrogen secondary batteries 2 are stacked via a metal conductive plate 3. The up-down direction of power storage device 1 coincides with the stacking direction (Z-axis direction) of nickel-hydrogen secondary battery 2. The nickel-hydrogen secondary battery 2 and the conductive plate 3 have, for example, a rectangular shape (a rectangular shape in a plan view) when viewed from the stacking direction. The conductive plate 3 is also disposed outside the nickel hydrogen secondary battery 2 positioned at the upper end and the lower end. The conductive plate 3 is electrically connected to the adjacent nickel hydrogen secondary battery 2. Thereby, a plurality of nickel hydrogen secondary batteries 2 are connected in series in the stacking direction. The nickel-hydrogen secondary battery 2 will be described in detail later.

  The positive electrode terminal 4 is connected to the lowermost conductive plate 3. The negative electrode terminal 5 is connected to the conductive plate 3 positioned on the uppermost side. The positive electrode terminal 4 and the negative electrode terminal 5 extend in a direction (X-axis direction) perpendicular to the stacking direction. By providing such a positive electrode terminal 4 and a negative electrode terminal 5, charging and discharging of the storage device 1 can be performed.

  The conductive plate 3 can also function as a heat sink for releasing the heat generated in the nickel-hydrogen secondary battery 2. The conductive plate 3 is provided with a plurality of air gaps 3 a extending in a direction (Y-axis direction) perpendicular to the stacking direction and the extending direction of the positive electrode terminal 4 and the negative electrode terminal 5. By passing a refrigerant such as air through these air gaps 3a, the heat from the nickel-hydrogen secondary battery 2 can be efficiently released to the outside.

  The storage device 1 further includes a restraint unit 6 for restraining the nickel hydrogen secondary battery 2 and the conductive plate 3 stacked alternately in the stacking direction. The restraint unit 6 includes a pair of restraint plates 7 sandwiching the nickel-hydrogen secondary battery 2 and the conductive plate 3 in the stacking direction, and a plurality of sets of bolts 8 and nuts 9 for fastening the restraint plates 7 to each other. There is.

  The restraint plate 7 is made of metal such as iron. Insulating films 10 such as resin films are respectively disposed between the restraint plates 7 and the conductive plate 3. The constraining plate 7 and the insulating film 10 have, for example, a rectangular shape in plan view. The constraining plate 7 is larger than the nickel hydrogen secondary battery 2, the conductive plate 3 and the insulating film 10 when viewed from the stacking direction.

  At the edge portion of the restraint plate 7, a plurality of insertion holes 7 a for inserting the shaft portion 8 a of the bolt 8 are provided. The nut 9 is screwed to the tip end of the shaft portion 8 a in a state where the shaft portion 8 a of the bolt 8 is inserted through the insertion hole 7 a of each restraint plate 7, the nickel hydrogen secondary battery 2, the conductive plate 3 and the insulating film 10 are clamped by a pair of restraint plates 7. Thereby, the restraint load in the stacking direction is applied to the nickel hydrogen secondary battery 2, the conductive plate 3 and the insulating film 10.

  FIG. 2 is a schematic cross-sectional view of the nickel-hydrogen secondary battery 2. In FIG. 2, the nickel-hydrogen secondary battery 2 includes an electrode stack 13 in which a plurality of bipolar electrodes 11 are stacked via a separator 12, and a frame 14 surrounding the electrode stack 13. The vertical direction of the electrode stack 13 coincides with the stacking direction (Z-axis direction) of the electrode stack 13.

  The bipolar electrode 11 and the separator 12 have, for example, a rectangular shape in plan view. The separator 12 is disposed between the bipolar electrodes 11 adjacent in the stacking direction. The bipolar electrode 11 includes a nickel foil 15 as a current collector, a positive electrode 16 formed on the upper surface 15 a (one surface) of the nickel foil 15, and a negative electrode 17 formed on the lower surface 15 b (the other surface) of the nickel foil 15. And. The thickness of the positive electrode 16 and the negative electrode 17 may be the same as the thickness of the nickel foil 15 or may be different from the thickness of the nickel foil 15.

  The positive electrode 16 of the bipolar electrode 11 faces the negative electrode 17 of one of the bipolar electrodes 11 adjacent in the stacking direction with the separator 12 interposed therebetween. The negative electrode 17 of the bipolar electrode 11 faces the positive electrode 16 of the other bipolar electrode 11 adjacent in the stacking direction with the separator 12 interposed therebetween.

  The positive electrode side termination electrode 18 is disposed in the lowermost layer (one outermost layer) of the electrode stack 13. That is, the positive electrode side termination electrode 18 is an electrode located at the lowermost side in the direction of gravity in the electrode stack 13 and at the outermost layer in the lamination direction in the electrode stack 13. The positive electrode side terminal electrode 18 has a nickel foil 15 and a positive electrode 16 formed on the upper surface 15 a (one surface) of the nickel foil 15. The negative electrode side termination electrode 19 is disposed in the uppermost layer (the other outermost layer) of the electrode stack 13. That is, the negative electrode side termination electrode 19 is an electrode located at the uppermost side in the direction of gravity in the electrode stack 13 and the outermost layer in the stacking direction in the electrode stack 13. The negative electrode side terminal electrode 19 has a nickel foil 15 and a negative electrode 17 formed on the lower surface 15 b (the other surface) of the nickel foil 15. The positive electrode 16 of the positive electrode side termination electrode 18 faces the negative electrode 17 of the lowermost bipolar electrode 11 with the separator 12 interposed therebetween. The negative electrode 17 of the negative electrode side termination electrode 19 is opposed to the positive electrode 16 of the uppermost bipolar electrode 11 with the separator 12 interposed therebetween. The nickel foils 15 of the positive electrode side termination electrode 18 and the negative electrode side termination electrode 19 are connected to the conductive plates 3 (see FIG. 1) adjacent in the stacking direction.

  The nickel foil 15 is a metal foil containing nickel (Ni) as a main component. The nickel foil 15 may be made only of Ni, or Ni may contain a slight additive or the like. The nickel foil 15 is formed by stamping Ni into a thin paper by rolling.

  The positive electrode 16 is formed by applying a positive electrode active material to one surface of the nickel foil 15. As the positive electrode active material, for example, nickel hydroxide coated with cobalt (Co) oxide is used. The negative electrode 17 is formed by applying a negative electrode active material to the other surface of the nickel foil 15. For example, a hydrogen storage alloy is used as the negative electrode active material.

  The edge 15 c of the nickel foil 15 is an uncoated region to which the positive electrode active material and the negative electrode active material are not applied. The coating region of the negative electrode active material (formation region of the negative electrode 17) on the lower surface 15b of the nickel foil 15 is larger than the coating region of the positive electrode active material (formation region of the positive electrode 16) on the upper surface 15a of the nickel foil 15.

  The separator 12 is disposed between the positive electrode 16 and the negative electrode 17 and separates the positive electrode 16 and the negative electrode 17. The separator 12 is smaller than the nickel foil 15 and larger than the positive electrode 16 and the negative electrode 17 when viewed in the stacking direction. The separator 12 is formed in, for example, a sheet shape. The separator 12 is formed of a porous film made of a polyolefin resin such as polyethylene (PE) or polypropylene (PP), or a non-woven or woven fabric made of PE, PP, polyethylene terephthalate (PET) or methylcellulose. The separator 12 may be reinforced with a vinylidene fluoride resin compound or the like. The shape of the separator 12 is not particularly limited to a sheet, and may be a bag.

  The frame body 14 has a primary seal member 20 (seal member) disposed so as to surround the electrode stack 13 and a secondary seal member 21 disposed around the primary seal member 20. The primary seal member 20 and the secondary seal member 21 are made of, for example, a resin such as polypropylene (PP), polyphenylene sulfide (PPS) or modified polyphenylene ether (modified PPE).

  An internal space V defined by the nickel foil 15, the positive electrode 16, the negative electrode 17, the separator 12 and the primary seal member 20 is disposed between the nickel foils 15 adjacent to each other in the stacking direction of the electrode stack 13. The internal space V is formed in a liquid tight manner. An alkaline electrolyte F is injected into the internal space V. As the alkaline electrolyte solution F, for example, an alkaline solution containing a potassium hydroxide aqueous solution or the like is used.

  The primary seal member 20 seals the internal space V. The primary seal member 20 has a rectangular tube shape having a rectangular shape in a plan view. The primary seal member 20 is composed of a side wall 20a, a side wall 20b opposite to the side wall 20a, and a pair of side walls 20c opposite in a direction perpendicular to the opposite direction of the side walls 20a and 20b. The width of the side wall 20a is larger than the width of the side walls 20b and 20c.

  In the side wall 20a of the primary seal member 20, a liquid reservoir portion 22 for storing the electrolytic solution F, and a communication portion 23 for communicating the internal space V located at the lower end in the stacking direction of the electrode stack 13 and the liquid reservoir portion 22. And are provided. The liquid reservoir 22 is provided on the side wall 20 a so as to extend in the stacking direction. The liquid reservoir portion 22 has a rectangular shape (cross-sectional rectangular shape) in a cross section perpendicular to the stacking direction of the electrode stack 13. An internal space V located at the lower end in the lamination direction of the electrode stack 13 is an internal space V corresponding to the positive electrode side termination electrode 18.

  As also shown in FIG. 3, the primary seal member 20 includes a plurality of seal frames 24 (first seal frame) for holding the edge 15 c of the nickel foil 15 of the bipolar electrode 11 and a nickel foil of the positive electrode side termination electrode 18. A seal frame 25 (second seal frame) for holding the edge portion 15c of 15 and a seal frame 26 (third seal frame) for holding the edge portion 15c of the nickel foil 15 of the negative electrode side termination electrode 19; A plurality of seal frames 27 (fourth seal frames) disposed between the seal frames 24 adjacent to each other in the stacking direction in the stacking direction, and a seal frame 28 disposed between the seal frame 24 and the seal frame 25 of the lowermost layer. A fifth seal frame) and a seal frame 29 (sixth seal frame) disposed between the seal frame 24 and the seal frame 26 of the uppermost layer.

  The seal frames 24 and 27 are welded, the seal frames 24 and 28 are welded, the seal frames 24 and 29 are welded, the seal frames 25 and 28 are welded, and the seal frames 26 and 29 are welded. There is. The seal frames 24 to 29 are welded to the edge 15 c of the nickel foil 15.

  The seal frame 24 has a liquid reservoir forming area 24 a in which the liquid reservoir portion 22 is formed. The width of the reservoir formation area 24 a is larger than the width of the other area in the seal frame 24. In the reservoir formation region 24 a, a reservoir hole 30 is provided which penetrates in the stacking direction of the electrode stack 13 and forms a part of the reservoir portion 22. The liquid reservoir hole 30 has, for example, a rectangular shape in plan view extending in the Y-axis direction.

  The seal frames 25 and 26 respectively have areas 25 a and 26 a corresponding to the liquid reservoir forming area 24 a of the seal frame 24.

  The seal frame 27 has a liquid reservoir forming area 27 a in which the liquid reservoir portion 22 is formed, corresponding to the liquid reservoir forming area 24 a of the seal frame 24. In the reservoir formation region 27a, a reservoir hole 31 which penetrates in the stacking direction of the electrode stack 13 and which forms a part of the reservoir portion 22 is provided. The shape and size of the liquid reservoir hole 31 are the same as those of the liquid reservoir hole 30.

  The seal frame 28 has a liquid reservoir forming area 28 a in which the liquid reservoir portion 22 is formed, corresponding to the liquid reservoir forming area 24 a of the seal frame 24. In the reservoir formation region 28 a, a reservoir hole 32 which penetrates in the stacking direction of the electrode stack 13 and which forms a part of the reservoir portion 22 is provided. The shape and dimensions of the liquid reservoir holes 32 are the same as those of the liquid reservoir holes 30. Further, the communication portion 23 described above is provided in the liquid storage area 28a. The communication portion 23 is in communication with the liquid reservoir hole 32.

  The seal frame 29 has a liquid reservoir forming area 29 a in which the liquid reservoir portion 22 is formed, corresponding to the liquid reservoir forming area 24 a of the seal frame 24. A liquid reservoir hole 33 is formed in the liquid reservoir formation region 29 a so as to penetrate in the stacking direction of the electrode stack 13 and to form a part of the liquid reservoir portion 22. The shape and size of the liquid reservoir hole 33 are the same as those of the liquid reservoir hole 30.

  The secondary seal member 21 has a rectangular cylindrical shape. The secondary seal member 21 surrounds the primary seal member 20 and further seals the internal space V. The secondary seal member 21 is welded to the outer side surface, the upper surface and the lower surface of the primary seal member 20.

  In the nickel hydrogen secondary battery 2 as described above, when the current flows, the creep phenomenon (alkali creep phenomenon) of the alkaline electrolyte solution F occurs. The alkaline creep phenomenon is a phenomenon in which the alkaline electrolyte solution F creeps up on the surface of the nickel foil 15. Electrolyte solution F which crawled up the surface of nickel foil 15 leaks from a junction interface of nickel foil 15 and primary seal member 20. Leakage of the electrolyte solution F due to such an alkaline creep phenomenon occurs regardless of the sealability between the nickel foil 15 and the primary seal member 20, and can not be avoided electrochemically.

  At this time, since the positively charged alkaline electrolyte F creeps up on the surface of the nickel foil 15, the electrolyte F from the positive electrode side (the positive electrode side termination electrode 18 side) to the negative electrode side (the negative electrode side termination electrode 19 side) Is more likely to leak. Therefore, the electrolyte solution F present in the internal space V corresponding to the negative electrode side termination electrode 19 leaks to the outside of the nickel hydrogen secondary battery 2. However, since the electrolytic solution F leaked from the internal space V adjacent to the lower side enters the internal space V corresponding to the negative electrode-side termination electrode 19, the electrolytic solution F does not run out as a result. However, the electrolytic solution F present in the internal space V corresponding to the positive electrode side termination electrode 18 only leaks into the internal space V adjacent to the upper side. As a result, the electrolyte solution F existing in the internal space V corresponding to the positive electrode side termination electrode 18 becomes insufficient.

  With respect to such a defect, in the present embodiment, the primary seal member 20 includes the liquid reservoir portion 22 for storing the alkaline electrolyte solution F, and the internal space V located at the lower end in the stacking direction of the electrode stack 13 ( A communication portion 23 is provided for connecting the internal space V) corresponding to the positive electrode side end electrode 18 and the liquid reservoir 22. For this reason, the electrolytic solution F injected into the internal space V corresponding to the positive electrode side termination electrode 18 creeps up on the surface of the nickel foil 15 due to the alkaline creep phenomenon, and a minute gap between the nickel foil 15 and the primary seal member 20 Even if the electrolyte solution F existing in the internal space V corresponding to the positive electrode side terminal electrode 18 decreases by leakage, the electrolytic solution F stored in the liquid storage part 22 passes through the communication part 23 and the positive electrode side terminal electrode The internal space V corresponding to 18 is supplied. That is, the electrolyte F is supplied from the liquid reservoir 22 to the internal space V corresponding to the positive electrode side termination electrode 18 as much as the electrolyte F existing in the internal space V corresponding to the positive electrode side termination electrode 18 disappears due to the alkaline creep phenomenon. It will be replenished. Thereby, the liquid withering of the electrolyte solution F in the internal space V corresponding to the positive electrode side termination electrode 18 is prevented. As a result, it is possible to prevent the decrease in output of the nickel hydrogen secondary battery 2.

  Further, in the present embodiment, the primary seal member 20 includes the seal frame 24 having the liquid reservoir hole 30, the seal frame 25, the seal frame 26, the seal frame 27 having the liquid reservoir hole 31, the liquid reservoir hole 32, A seal frame 28 having a communicating portion 23 and a seal frame 29 having a liquid reservoir hole 33 are provided. As a result, the primary seal member 20 having the liquid reservoir 22 and the communication portion 23 can be easily formed.

  Further, in the present embodiment, the positive electrode side termination electrode 18 is disposed in the lowermost layer of the electrode stack 13, and the seal frame 25 holding the nickel foil 15 of the positive electrode side termination electrode 18 is the outermost of the primary seal member 20. It is arranged in the lower layer. In such a configuration, when the amount of electrolyte present in the internal space V corresponding to the positive electrode side termination electrode 18 decreases due to the alkaline creep phenomenon, electrolysis causes the electrolytic solution to flow from the liquid reservoir 22 to the internal space V corresponding to the positive electrode side termination electrode 18 by gravity. Liquid F is supplied. Therefore, replenishment of the electrolyte solution F to the internal space V corresponding to the positive electrode side termination electrode 18 is performed simply and reliably.

  The present invention is not limited to the above embodiment. For example, in the above embodiment, one liquid reservoir 22 is provided on the side wall 20a of the primary seal member 20. However, the present invention is not particularly limited to that configuration, and two liquid reservoirs 22 are provided on the side wall 20a of the primary seal member 20. More than one may be provided. Moreover, in the said embodiment, although the liquid storage part 22 is provided only in the side wall 20a of the primary sealing member 20, it is not restricted in particular to that form, either the liquid storage part 22 is also included in the side walls 20b and 20c of the primary sealing member 20. May be provided. In this case, the width of the side walls 20b and 20c may be the same as the width of the side wall 20a.

  Further, in the above embodiment, the liquid reservoir portion 22 has a rectangular cross-sectional shape, but the shape of the liquid reservoir portion 22 is not particularly limited to the cross-sectional rectangular shape, but is an oval cross-sectional shape or a cross-sectional perfect circular shape May be Further, the width dimension and the height dimension of the liquid reservoir 22 are not particularly limited.

  Further, in the above embodiment, the vertical direction of the electrode stack 13 coincides with the stacking direction (Z-axis direction) of the electrode stack 13, but the invention is not particularly limited to that form, and the vertical direction of the electrode stack 13 May coincide with the X axis direction or the Y axis direction.

  Furthermore, in the above embodiment, the communication portion 23 communicates the internal space V (the internal space corresponding to the positive electrode side end electrode 18) located at the lower end in the stacking direction of the electrode stack 13 with the liquid reservoir 22. However, it is not particularly limited to that form. For example, when the vertical direction of the electrode stack 13 coincides with the X-axis direction or the Y-axis direction, the communication portions 23 are provided on the seal frame 28 and positioned at both ends in the stacking direction of the electrode stack 13. The internal space V corresponding to the positive electrode side end electrode 18 which is one of the two internal spaces V may communicate with the liquid reservoir 22 or may be provided on the seal frame 29 and both ends of the electrode stack 13 in the lamination direction. The internal space V corresponding to the negative electrode side terminal electrode 19 which is the other of the two internal spaces V located in the and the liquid reservoir 22 may be communicated.

  In the above-mentioned embodiment, although primary seal member 20 has a plurality of seal frames 24 and a plurality of seal frames 27, the number of seal frames 24 and 27 is not particularly limited thereto. For example, the number of seal frames 24 may be two and the number of seal frames 27 may be one.

  Moreover, in the said embodiment, although the frame 14 has the secondary seal member 21 arrange | positioned around the primary seal member 20, such secondary seal member 21 does not need to be especially.

  Furthermore, although the nickel foil 15 is used as the current collector in the above embodiment, the current collector is not particularly limited to the nickel foil 15. For example, a nickel-plated steel plate in which a thin steel plate is plated with nickel It is also good.

  2 ... nickel hydrogen secondary battery, 11 ... bipolar electrode, 12 ... separator, 13 ... electrode laminate, 15 ... nickel foil (current collector), 15a ... top surface (one surface), 15b ... bottom surface (other surface), 16 ... Positive electrode, 17 ... Negative electrode, 18 ... Positive electrode side terminal electrode, 19 ... Negative electrode side terminal electrode, 20 ... Primary seal member (seal member), 22 ... Liquid storage part, 23 ... Communication part, 24 ... Seal frame (1st seal Frames, 25: seal frame (second seal frame), 26: seal frame (third seal frame), 27: seal frame (fourth seal frame), 28: seal frame (fifth seal frame), 29: seal Frame (sixth seal frame), 30: liquid reservoir hole, 31: liquid reservoir hole, 32: liquid reservoir hole, 33: liquid reservoir hole, F: electrolyte solution, V: internal space.

Claims (4)

In a nickel-hydrogen secondary battery, comprising: an electrode stack in which a plurality of bipolar electrodes are stacked via a separator; and a seal member arranged to surround the electrode stack.
The bipolar electrode includes a current collector containing nickel, a positive electrode formed on one side of the current collector, and a negative electrode formed on the other side of the current collector.
In one outermost layer of the electrode stack, a positive electrode side end electrode having the positive electrode formed on one surface of the current collector is disposed to face the bipolar electrode with the separator interposed therebetween.
In the other outermost layer of the electrode laminate, a negative electrode-side terminal electrode having the negative electrode formed on the other surface of the current collector is disposed to face the bipolar electrode with the separator interposed therebetween.
An internal space defined by the current collector, the positive electrode, the negative electrode, the separator, and the seal member is disposed between the current collectors adjacent in the stacking direction in the electrode stack.
An alkaline electrolyte is injected into the internal space,
The seal member includes a liquid reservoir for storing the electrolytic solution, and a communication portion for communicating one of the two internal spaces located at both ends in the stacking direction of the electrode stack with the liquid reservoir. And a nickel hydrogen secondary battery characterized by being provided. The seal member includes a plurality of first seal frames for holding the current collector of the bipolar electrode, a second seal frame for holding the current collector of the positive electrode side terminal electrode, and the negative electrode side terminal electrode A third seal frame for holding a current collector, at least one fourth seal frame disposed between the first seal frames adjacent to each other in the stacking direction of the electrode stack, the first seal frame, and A fifth seal frame disposed between the second seal frame and a sixth seal frame disposed between the first seal frame and the third seal frame;
A liquid reservoir hole which penetrates through the first seal frame, the fourth seal frame, the fifth seal frame, and the sixth seal frame in the laminating direction of the electrode stack and forms a part of the liquid reservoir portion Are provided respectively,
The nickel hydrogen secondary battery according to claim 1, wherein the communication portion is provided in the fifth seal frame or the sixth seal frame, and is connected to the liquid reservoir hole.   The nickel hydrogen secondary battery according to claim 2, wherein the communication portion is provided in the fifth seal frame and is connected to the liquid reservoir hole. The positive electrode side end electrode is disposed in the lowermost layer of the electrode stack,
The nickel hydrogen secondary battery according to claim 3, wherein the second seal frame is disposed in the lowermost layer of the seal member.

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