JPH0682759U - Current collector for zinc-bromine battery - Google Patents

Abstract

(57) [Abstract] [Purpose] A zinc-bromine battery that prevents "warpage" of the collecting electrode due to thermal stress and external force and increases the mechanical strength of the collecting electrode itself to reduce fatigue rupture. It is intended to provide a collecting electrode. An insulating frame member 16 having a hole 17 into which an electrode part is inserted, and a metal made of an insulator filled and welded in a large number of holes 22a opened at appropriate positions of an iron plate or a stainless plate 22- Insulator integrated frame member 18, the metal-insulator integrated frame member 18 and carbon plastic electrode 15
a, 15b, 15c, and an electrode portion 30 integrally formed of a laminated body of the current collecting mesh 6 by a heat pressing means, and a packing 19 and an auxiliary sealing mechanism 31 are provided in the hole portion 17 of the insulating frame member 16. Thus, the current collecting electrode of the zinc-bromine battery having the electrode part 30 inserted therein is provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a collecting electrode which is a constituent member of an electrolyte circulating type laminated secondary battery, particularly a zinc-bromine battery.

[0002]

[Prior art]

 Zinc-bromine batteries are secondary batteries that use bromine as the positive electrode active material and zinc as the negative electrode active material. For example, this battery is used at night when power demand is low to solve the imbalance between day and night. It is used to store electricity and discharge it in the daytime.

Bromine generated on the positive electrode side at the time of charging reacts with the bromine complexing agent added to the electrolytic solution to be returned as an oily precipitate to the storage tank, and at the time of discharging it is pumped into the unit cell. It is sent and returned. The components of the electrolytic solution are a ZnBr ₂ aqueous solution, a salt such as NH ₄ Cl for reducing the resistance, and Pb, Sn, and quaternary ammonium salts for preventing dendrite on the negative electrode zinc side and promoting uniform electrodeposition. , With a bromine complexing agent. A separator is inserted between the positive electrode and the negative electrode to prevent self-discharge due to the bromine generated in the positive electrode diffusing into the negative electrode and reacting with zinc.

The chemical reaction of this zinc-bromine battery is

[0005]

[Chemical Formula 1] During charging: Positive electrode: 2Br ⁻ → Br ₂ + 2e ⁻ , Negative electrode: Zn ⁺⁺ + 2e ⁻ → Zn During discharging: Positive electrode: 2Br ⁻ ← Br ₂ + 2e ⁻ , Negative electrode: Zn ⁺⁺ + 2e ⁻ ← Zn It is represented by.

This zinc-bromine battery is mainly of a bipolar type and has a battery main body in which a plurality of cells (cells) are electrically stacked in series, an electrolytic solution storage tank, and a space between them. It consists of a pump and a piping system that circulates the electrolyte.

FIG. 6 is an exploded perspective view showing an example of a battery body constituting the above zinc-bromine battery, in which an insulating frame 1b is arranged on the outer periphery of an electrode portion 1a of a bipolar plate-shaped intermediate electrode 1 having a rectangular flat plate shape. Similarly, in the separator plate 2 having a rectangular flat plate shape, the frame body 2 a is formed on the outer periphery of the separator 3. The separator plate 2 and, if necessary, the packing 4 and the spacer mesh 5 are stacked on the intermediate electrode 1 to form a single cell, and a plurality of the single cells are laminated to form a battery body.

A collector electrode 7 having a collector mesh 6, a pair of tightening end plates 8 and a stacking end plate 9 for pressing, which is located inside the collector electrodes 7, are provided at both ends of the stacked battery bodies. It is arranged. Then, a bolt (not shown) is passed between both the tightening end plates 8 and 8 to fasten the bolt to form a battery body integrally laminated and fixed.

In each unit cell of the battery main body configured as described above, a positive electrode manifold 10 formed at two upper and lower corners of the intermediate electrode 1 and the frame body 2 a of the separator plate 2, The electrolyte solution flows in and out from the negative electrode manifold 11 through the channels 12 and the microchannels 13 provided in the frame body 2a of the separator plate 2, respectively.

It has been confirmed that the zinc-bromine battery configured as described above has a battery efficiency of about 80% in a 50 KW class battery and an overall energy efficiency of about 70%.

As shown in FIGS. 7 and 8, the current collecting electrode 7 has a carbon plastic electrode 15 incorporated in a hole 17 formed in a sheet-shaped insulating frame member 16, and a metal mold not shown is used. It is manufactured integrally by using a heat pressing means under predetermined temperature and pressure conditions. As conditions for this heat press, for example, 150 ° C. and 55 kg / cm ² are adopted. The carbon plastic electrode 15 is a member formed by mixing polyethylene and carbon graphite, and has corrosion resistance against bromine.

Reference numeral 6 denotes a brass current collecting mesh integrally incorporated in the carbon plastic electrode 15, and the terminal piece 6 a for extracting electric power, which is derived from the current collecting mesh 6, is formed on the insulating frame member 16. It is led out through the slit 14 and is connected to a current collecting bus bar (not shown). Arrow A in the figure indicates the back side of the battery body, and arrow B indicates the liquid contact side.

[0013]

[Problems to be solved by the device]

 However, in the case of the current collecting electrode 7 used in such a conventional zinc-bromine battery, the thermal contraction rate and the linear expansion coefficient are determined based on the difference in material between the back side A and the liquid contact side B with respect to the electrolytic solution. It is unavoidable that a difference occurs, and especially when the temperature decreases, the sheet-like insulating frame member 16 may "warp" due to the difference in the heat shrinkage ratio, which may reduce the flatness of the current collector electrode. Occurs.

When the flatness of the collector electrode 7 is reduced, as described in FIG. 6 above, when the clamp end plates 8, 8 constituting the battery body are tightened with bolts, the collector electrode 7 The liquid easily leaks from the interface of No. 7 and the stored electric power is lost. If the tightening force of the bolts is increased in order to eliminate this liquid leakage, there is a problem in that the stress concentrated on the interface easily causes the cracks in the constituent members.

As a countermeasure against the above, a means for attaching a disc spring to a bolt to minimize a load change is usually used. However, since the expansion displacement due to a temperature change cannot be absorbed, a tightening pressure There is a risk of time-delayed rupture due to creep associated with rising, and it remains a problem that it cannot be said to be sufficient as a crack prevention measure.

The insulating frame member 16 is generally made of a mixture of polyethylene resin and talc, and has a smaller “elongation” at break than a pure polyethylene resin, which also causes the cracks. ing.

Further, since the carbon plastic electrode 15 is a member formed by mixing polyethylene and carbon graphite as described above in order to enhance the conductivity, it contains a large amount of inorganic filler, and the insulating frame member 16 and In addition to its poor weldability, the electrode itself has the property of being hard and brittle, so that it lacks followability to mechanical strain due to an external force, and is a factor that cracks and breaks easily occur.

Further, the collector electrode 7 is alternately applied with a positive pressure which is pressed from the carbon plastic electrode side by the pressure of the pump and a negative pressure which is generated when the electrolytic solution is drained and which pulls the carbon plastic. Therefore, consideration for fatigue fracture is required.

The present invention has been made in view of the above points, and causes a warp phenomenon caused by thermal contraction of a current collecting electrode and a characteristic defect such as electrolyte leakage caused by the warp phenomenon. It is an object of the present invention to provide a current collecting electrode for a zinc-bromine battery that eliminates the cause and has improved anti-fatigue properties.

[0020]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention forms a single cell by stacking a separator plate on a rectangular flat plate-shaped intermediate electrode, and stacks a plurality of the single cells to form a battery main body. A pair of collector electrodes and a clamp end plate are arranged at both ends, and the clamp electrodes are clamped together by bolts between the clamp end plates so that they are integrally laminated and fixed. Frame member having a hole into which a part is inserted, a metal-insulator integrated frame member made of an insulator filled and welded in a large number of holes opened at appropriate positions of an iron plate, and this metal-insulation And a carbon plastic electrode, and an electrode part integrally formed by a heat press means with a laminated body of a carbon plastic electrode, and a packing and an auxiliary seal mechanism interposed in the hole of the insulating frame material. Zinc with electrode inserted- It is the structure of the collecting electrode of the unit cell. A stainless plate may be used instead of the iron plate.

The auxiliary seal mechanism includes a packing rib standing up along the hole of the insulating frame member, a side packing fitted to the upper part of the packing rib, and a holding plate arranged above the side packing. The packing rib, the side packing, and the pressing plate are connected to each other in a V-shaped cross section. Further, a plurality of bolts protruding from a predetermined position of the iron plate to the back side are provided, and a nut hole into which the bolt can be screwed is formed at a predetermined position of the insulating frame member.

[0022]

[Action]

 According to such a collecting electrode, the electrode part mainly composed of the carbon plastic and the metal-insulator integrated frame member and the insulating frame member are configured as substantially separate bodies, and the packing and the auxiliary seal mechanism are formed. The tightening force of the bolts used maintains the liquid tightness of both. Therefore, the occurrence of “warpage” of the collecting electrode due to heat shrinkage, etc. is prevented, the electrolyte leaks due to such warpage, the occurrence of cracks due to excessive bolt tightening and the breakage of the electrode part and insulating frame material. The effect of not occurring is obtained.

As the auxiliary sealing mechanism, a packing rib and a side packing and a pressing plate fitted to the upper part of the packing rib are adopted, and the upper and lower surfaces of each joint are V-shaped in cross section. The liquid tightness between the material and the electrode portion can be further enhanced.

Further, since the metal-insulator integrated frame member having a relatively large thickness is interposed in the electrode part, the mechanical strength of the obtained current collecting electrode itself is increased, and the positive pressure to the current collecting electrode is increased. This has the effect of reducing fatigue rupture due to the alternating application of negative pressure and negative pressure.

By using a stainless steel plate in place of the iron plate that constitutes the metal-insulator integrated frame member, in addition to the above-mentioned action, the corrosion resistance of the stainless steel plate itself collects electricity due to bromine contained in the electrolytic solution. Corrosion of the electrodes is effectively prevented.

[0026]

【Example】

 Hereinafter, referring to the drawings, a specific embodiment of a current collecting electrode of a zinc-bromine battery according to the present invention will be described in which the same components as those shown in FIGS. Detailed description.

FIG. 1 is an exploded cross-sectional view of an essential part showing the structure of the collector electrode 7 according to this embodiment. In the figure, 15a and 15a are carbon plastic electrodes having a thickness of 1 mm, and a brass current collecting mesh 6 is arranged on the back side A of these two carbon plastic electrodes 15a and 15a. A carbon plastic electrode 15b having a thickness of 1 mm is arranged on the back side A of the.

On the back side A of the carbon plastic electrode 15b, a metal-insulator integrated frame member 18, which is one of the characteristic constituent members of the present invention, is arranged, and A carbon plastic electrode 15c and a Teflon packing 19 are arranged on the back side A of the body frame member 18. An O-ring made of fluororubber can be used instead of the packing 19.

Reference numeral 16 is an insulating frame member arranged on the back side A of the packing 19. A hole 17 into which an electrode portion is inserted is formed in the insulating frame member 16, and bolts 24, 24 protruding from the metal-insulator integrated frame member 18 are provided at predetermined positions of the insulating frame member 16. Nut holes 25, 25 that can be screwed are provided.

The terminal piece 6 a taken out from the current collecting mesh 6 is preliminarily opened in the insulating frame member 16 from the carbon plastic electrode 15 b, the metal-insulator integrated frame member 18, the carbon plastic electrode 15 c and the packing 19. It passes through the hole and is guided to the outside of the insulating frame member 16.

A specific structure of the metal-insulator integrated frame member 18 will be described with reference to the liquid contact side plan view of FIG. 2 and the back side plan view of FIG. That is, the metal-insulator-integrated frame member 18 has an insulative frame member 21 located in the outer peripheral portion and a position surrounded by the frame member 21, and a large number of holes 22a are opened. The iron plate 22, the insulator 23 integrally welded in a state of being filled in the hole 22a, and a plurality of bolts 24, 24 protruding from a predetermined position of the iron plate 22 in the rear side A direction (illustrated example). 4) and. In this embodiment, the metal-insulator integrated frame member 18 has a thickness of 5 mm or more. Further, it is possible to use a stainless plate instead of the iron plate 22.

In this metal-insulator integrated frame member 18, an iron plate 22 having holes 22 a opened in advance is arranged inside the frame body 21 prior to the assembling of the collector electrode 7. The hole 23a is filled with the insulator 23 and heat-pressed at 150 ° C. and about 55 kg / cm ² by using a mold to integrally weld and prefabricate.

At the time of assembling the collector electrode 7, first, a metal mold (not shown) is used to manufacture the electrode portion. The carbon plastic electrodes 15a, 15a, the collector mesh 6, the carbon plastic electrode 15b, the metal- The insulator-integrated frame member 18 and the carbon plastic 15c are laminated and integrally molded under the conditions of heat pressing means, for example, 150 ° C. to 180 ° C. and a pressing pressure of 55 kg / cm ² .

FIG. 4 shows the structure of an auxiliary seal mechanism 31 provided between the insulating frame member 16 and the electrode section 30. The auxiliary seal mechanism 31 stands up from the insulating frame member 16 along the hole 17. The packing rib 33 is raised, the side packing 34 is fitted to the upper part of the packing rib 33, and the pressing plate 35 is arranged above the side packing 34. A fluorine-based rubber material is used for the side packing 34.

The packing rib 33 is formed integrally with the insulating frame member 16, and the side packing 34 and the holding plate 35 are separately prepared. Each of the joints of the packing rib 33, the side packing 34, and the holding plate 35 has a V-shaped cross section on both the upper and lower surfaces, and is configured to enhance liquid tightness.

Then, the bolt 24 protruding from the electrode portion 30 is inserted into the nut hole 25 with the packing 19 interposed therebetween, and is screwed and fixed by using the nut 26 arranged in the nut hole 25. The current collector 7 having the portion 30 screwed and fixed in the hole 17 of the insulating frame member 16 is obtained. FIG. 5 is a plan view of the obtained current collecting electrode 7. As shown in the drawing, the carbon plastic electrode 15a located at the center and the insulating frame member 16 are joined in a liquid-tight state with the auxiliary seal mechanism 31 interposed. Has been done.

When the obtained collector electrode 7 is assembled to the battery body, a bolt (not shown) inserted between the tightening end plates 8 located outside the pair of laminated end plates 9 shown in FIG. 6 is used. By tightening, the electrode portion 30 and the insulating frame member 16 are liquid-tightly sealed in the presence of the auxiliary sealing mechanism 31, and the hermeticity with respect to the electrolytic solution is maintained well.

Therefore, according to the present embodiment, the electrode portion mainly composed of the carbon plastic electrodes 15a, 15b, 15c and the metal-insulator integrated frame member 18 and the insulating frame member 16 are provided with the auxiliary seal mechanism 31 interposed therebetween. It is characterized in that it is assembled in a liquid-tight manner and the sealing performance is maintained by the tightening force of the bolt using the packing 19.

According to the current collecting electrode 7 of the present embodiment, the electrode portion 30 having a different coefficient of thermal expansion and the insulating frame member 16 are separate bodies, so that the current collecting electrode 7 caused by thermal contraction or the like is not formed. The function of preventing the occurrence of "warpage" and preventing the leakage of electrolyte due to such "warpage", the occurrence of cracks due to excessive bolt tightening, and the breakage of the electrode part and insulating frame material Is obtained. Further, by adopting the packing made of Teflon as the packing 19, the corrosion resistance to the electrolytic solution containing bromine can be enhanced.

Further, since the metal-insulator-integrated frame member 18 has the holes 23 a of the iron plate 22 arranged inside the frame body 21 filled with the insulator 23 and welded together, the carbon plastic The interfacial adhesion with the electrode is enhanced, and the presence of the iron plate 22 improves the weldability with the carbon plastics 15a and 15b.

Further, it is considered that the “warpage” occurs due to the difference in thermal expansion coefficient between the carbon plastics 15a, 15b, 15c forming the electrode portion and the iron plate 22 forming the metal-insulator integrated frame member 18. However, in such a case, by making the thickness of the iron plate 22 larger than the thickness of the carbon plastic electrodes 15a, 15b, 15c, the thermal expansion amount of the carbon plastic electrodes 15a, 15b, 15c is increased. 2, so that the warpage is prevented from occurring.

Further, since the metal-insulator-integrated frame member 18 having a relatively large thickness is interposed in the electrode portion, the thickness of the obtained collector electrode 7 itself becomes 8 mm or more, which increases the thickness. Accordingly, the mechanical strength is increased, and a rigid structure is obtained as a whole by the built-in iron plate 22, which reduces fatigue rupture due to alternating positive and negative pressures applied to the collector electrode 7 by the pump. It is useful to consider.

When stainless steel is used instead of the iron plate 22, this stainless steel itself has higher corrosion resistance than the iron plate, so that corrosion of the current collecting electrode due to bromine contained in the electrolytic solution is effectively prevented. The unique effect of being performed is obtained.

[0044]

[Effect of device]

 As described in detail above, according to the current collecting electrode of the zinc-bromine battery according to the present invention, the electrode portion mainly composed of carbon plastic and the metal-insulator integrated frame member and the insulating frame material are substantially formed. The electrode part is fixed to the insulating frame material with the packing and the auxiliary seal mechanism interposed, so that the sealability between the two is maintained, and the “sledding” of the current collecting electrode caused by heat shrinkage is caused. It is possible to obtain the effect that the occurrence of “” does not occur, the leakage of the electrolytic solution, the occurrence of cracks due to excessive bolt tightening and the breakage of the insulating frame material do not occur. In particular, a packing rib and a side packing and a pressing plate fitted on the upper part of the packing rib are used as an auxiliary sealing mechanism between the insulating frame member and the electrode section, and each joint has a cross-section V on both the upper and lower surfaces. By forming the character shape, the liquid tightness between the insulating frame member and the electrode portion can be further enhanced.

Further, since the relatively thick metal-insulator integrated frame member is interposed in the electrode portion, the mechanical strength of the obtained collecting electrode itself is increased, and the positive pressure to the collecting electrode is increased. This has the effect of reducing fatigue rupture due to the alternating application of negative pressure and negative pressure.

On the other hand, by using a stainless steel plate instead of the iron plate that forms the metal-insulator integrated frame member, the corrosion resistance of the stainless steel plate itself causes the collector electrode of the collector electrode due to the bromine contained in the electrolytic solution. Corrosion can be prevented, and the bolts projecting from the specified position on the iron plate to the back side and the nut holes drilled at the specified positions of the insulating frame material insulate the electrode part with the packing interposed. By inserting the bolt into the nut hole after inserting it into the hole of the frame member, it is possible to obtain a desired sealing property of the collector electrode itself.

Therefore, according to the present invention, the warping phenomenon caused by the heat shrinkage of the current collecting electrode and the cause of the characteristic failure such as the electrolyte leakage due to the warping phenomenon are eliminated, and the mechanical strength is eliminated. There is provided a zinc-bromine battery current collecting electrode having enhanced electrical characteristics.

[Brief description of drawings]

FIG. 1 is an exploded cross-sectional view of an essential part showing a collector electrode of a zinc-bromine battery according to the present invention.

FIG. 2 is a plan view of the metal-insulator integrated frame member, which is a component of FIG. 1, on the liquid contact side.

3 is a rear side plan view of the metal-insulator integrated frame member which is a component of FIG. 1. FIG.

FIG. 4 is an enlarged sectional view of an essential part showing the structure of an auxiliary seal mechanism adopted in this embodiment.

FIG. 5 is a plan view of a current collecting electrode obtained in this example.

FIG. 6 is an exploded perspective view of essential parts showing a battery body of a zinc-bromine battery.

FIG. 7 is a plan view showing a structural example of a conventional collector electrode.

FIG. 8 is a cross-sectional view of an essential part showing a structural example of a conventional collector electrode.

[Explanation of symbols]

 6 ... Current collecting mesh 6a ... Terminal piece 7 ... Current collecting electrode 15a, 15b, 15c ... Carbon plastic electrode 16 ... Insulating frame material 17 ... Hole part 18 ... Metal-insulator integrated frame member 19 ... Packing 21 ... Frame body 22 ... Iron plate 22a ... Hole 23 ... Insulator 24 ... Bolt 25 ... Nut hole 30 ... Electrode 31 ... Auxiliary sealing mechanism 33 ... Packing rib 34 ... Side packing 35 ... Holding plate

Claims (4)

[Scope of utility model registration request] 1. A rectangular flat plate-shaped intermediate electrode is laminated with a separator plate to form a single cell, and a plurality of the single cells are laminated to form a battery main body, and a pair of collectors are provided at both ends of the battery main body. In the collector electrode of the zinc-bromine battery, in which the electrode electrode and the tightening end plate are arranged, and the tightening end plates are bolted together to integrally fix them in layers, the hole where the electrode part is inserted An insulating frame member having a metal-insulator integrated frame member made of an insulator filled and welded in a large number of holes opened at appropriate positions of an iron plate, and the metal-insulator integrated frame member and carbon A structure in which a laminated body of a plastic electrode and a current collecting mesh is integrally formed by heat pressing means, and the electrode portion is inserted into the hole of the insulating frame member with a packing and an auxiliary sealing mechanism interposed. Zinc characterized by having The collector electrode of bromine battery. 2. The auxiliary seal mechanism is a packing rib that rises along a hole of an insulating frame member, a side packing fitted to an upper part of the packing rib, and a holding plate arranged above the side packing. The current collecting electrode for a zinc-bromine battery according to claim 1, wherein each of the joints of the packing rib, the side packing, and the pressing plate has a V-shaped cross section. 3. A plurality of bolts protruding from a predetermined position of the iron plate to the back side are provided, and a nut hole into which the bolt can be screwed is formed at a predetermined position of the insulating frame member. The current collecting electrode of the zinc-bromine battery according to claim 1. 4. The current collecting electrode for a zinc-bromine battery according to claim 1, wherein a stainless plate is used instead of the iron plate.