JP3141599B2 - Current collecting electrode of zinc-bromine battery and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolyte circulation type laminated secondary battery, and more particularly to a current collecting electrode which is a component of a zinc-bromine battery.

[0002]

2. Description of the Related Art A zinc-bromine battery is a secondary battery in which bromine is used as a positive electrode active material and zinc is used as a negative electrode active material.
It is used for storing electric power at night when power demand is small and releasing it during the day.

[0003] The bromine generated on the positive electrode side during charging reacts with the bromine complexing agent added to the electrolytic solution, returns to the storage tank as an oily precipitate, and is discharged into the unit cell by a pump during discharging. It is sent and reduced. The component of the electrolyte is ZnBr ₂
An aqueous solution, a salt such as NH ₄ Cl for lowering resistance, Pb, Sn, quaternary ammonium salts for preventing dendrite on the negative electrode zinc side and promoting uniform electrodeposition, and a bromine complexing agent is there. A separator is interposed between the positive electrode and the negative electrode to prevent self-discharge caused by bromine generated at the positive electrode diffusing into the negative electrode and reacting with zinc.

The chemical reaction of this zinc-bromine battery is as follows:

[0005]

Embedded image At the time of charging: positive electrode: 2Br ⁻ → Br ₂ + 2e ⁻ , negative electrode: Zn
⁺⁺ + 2e ⁻ → Zn Discharge… Positive electrode: 2Br ⁻ ← Br ₂ + 2e ⁻ , Negative electrode: Zn
⁺⁺ + 2e ⁻ ← Represented by Zn.

This zinc-bromine battery mainly has a bipolar type electrode, a battery body in which a plurality of unit cells (single cells) are electrically stacked in series, an electrolytic solution storage tank, and an electrolytic solution between them. It is composed of a pump and a piping system for circulating the liquid.

FIG. 6 is an exploded perspective view showing an example of a battery main body constituting the zinc-bromine battery. An insulating frame 1b is arranged on the outer periphery of an electrode portion 1a of a bipolar plate-like bipolar intermediate electrode 1. Similarly, the rectangular flat separator plate 2
Has a frame 2 a 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.

[0008] At both ends of the stacked battery main body, a collecting electrode 7 having a collecting mesh 6, a pair of tightening end plates 8,
A holding laminated end plate 9 located on the inside thereof is arranged. Then, a bolt (not shown) is passed between the two tightening end plates 8 and 8, and the bolts are tightened to form a battery body integrally laminated and fixed.

In each unit cell of the battery body constructed as described above, each intermediate electrode 1 and the frame 2a of the separator plate 2 are provided.
Positive electrode manifold 10 formed at the upper and lower two corners of
Then, the electrolyte flows in and out of the negative electrode manifold 11 through the channel 12 and the micro channel 13 provided in the frame 2a of the separator plate 2, respectively.

[0010] The zinc-bromine battery thus constructed is
It has been confirmed that the battery efficiency of a 50 kW class battery is about 80%, and the total energy efficiency is about 70%.

As shown in FIGS. 7 and 8, the current collecting electrode 7 incorporates a carbon plastic electrode 15 into a hole 17 formed in a sheet-like insulating frame member 16 and utilizes a mold (not shown). Then, they are integrally manufactured based on heat press means under predetermined temperature and pressure conditions. As the conditions of the heat press, for example, 150 ° C. and 55 kg / cm ² are employed. The carbon plastic electrode 15 is a member formed by mixing polyethylene and carbon graphite, and has corrosion resistance to bromine.

Reference numeral 6 denotes a brass current collecting mesh integrally incorporated in the carbon plastic electrode 15, and a power take-out terminal strip 6a derived from the current collecting mesh 6.
Are led out through the slits 14 formed in the insulating frame member 16 and 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]

However, in the case of the current collecting electrode 7 used in such a conventional zinc-bromine battery, a difference in material between the back side a and the liquid contact side b with respect to the electrolyte is taken into consideration. It is inevitable that a difference occurs between the heat shrinkage and the coefficient of linear expansion. Particularly, when the temperature is lowered, the warp occurs in the insulating frame member 16 due to the difference in the heat shrinkage, and the flatness of the current collecting electrode May be reduced.

When the flatness of the current collecting electrode 7 is reduced, as described with reference to FIG. 6, when the clamping end plates 8 constituting the battery body are tightened with bolts, the current collecting electrode 7 7 easily leaks from the interface of No. 7, causing a loss of stored power. If the tightening force of the bolt is increased to eliminate the liquid leakage, there is a problem that the cracks are easily generated in the constituent members due to the stress concentrated on the interface.

As a countermeasure against the above, a means for minimizing a load change by attaching a disc spring to a bolt is usually used. However, since the expansion displacement due to a temperature change cannot be absorbed, the tightening pressure is reduced. There is a concern that the ascending may cause breakage with a time delay due to creep, and there remains a problem that it is not always sufficient as a measure for preventing cracks.

The insulating frame material 16 is generally made of a mixture of talc and polyethylene resin, and has a smaller "elongation" at break than pure polyethylene resin, which is a cause of the cracks. I have.

Further, since the carbon plastic electrode 15 is a member formed by mixing polyethylene and carbon graphite as described above in order to enhance conductivity,
It contains a large amount of an inorganic filler, has poor adhesion to the insulating frame material 16, has a property that the electrode itself is hard and brittle, and lacks the ability to follow mechanical strain due to external force, and the cracks occur, This is also a factor that easily causes breakage.

The collector electrode 7 has a positive pressure that is pressed from the carbon plastic electrode side by the pressure of the pump.
Since negative pressure pulling the carbon plastic generated when draining the electrolytic solution is applied alternately, consideration for fatigue fracture is required.

The present invention has been made in view of the above points, and has been described in connection with a warp phenomenon caused by heat shrinkage of a current collecting electrode and a cause of inducing characteristic defects such as electrolyte leakage due to the warp phenomenon. It is an object of the present invention to provide a current-collecting electrode for a zinc-bromine battery which eliminates the problem and has improved anti-fatigue properties.

[0020]

According to the present invention, in order to achieve the above object, a single plate is formed by stacking a separator plate on a rectangular flat intermediate electrode, and a plurality of such single cells are laminated to form a battery body. A zinc-bromine having a pair of current collecting electrodes and a clamped end plate arranged at both ends of the battery body, and integrally fixed by bolting between the clamped end plates. According to a first aspect of the present invention, there is provided a collector electrode for a battery, comprising: an insulator filled and welded in a large number of holes opened at appropriate positions in an iron plate surrounded by an insulating frame located at an outer peripheral portion. A metal-insulator-integrated frame member, and an electrode portion formed by laminating the metal-insulator-integrated frame member, a carbon plastic electrode, and a current collecting mesh and integrally forming the same by a heat press means, with an insulating frame interposed by packing. Into the hole of the material Zinc has a with the structure - to provide a structure of collecting electrode bromine battery. A plurality of bolts projecting rearward from a predetermined position of the iron plate are provided, and a nut hole into which the bolt can be screwed is formed at a predetermined position of the insulating frame material. Further, the present invention provides a current collecting electrode structure using a stainless steel plate instead of the iron plate.

According to a second aspect of the present invention, an iron plate or a stainless steel plate having a hole is disposed inside the frame, and an insulator is filled in the hole of the iron plate or the stainless plate.
A metal-insulator-integrated frame member integrally welded by heat pressing means using a mold is preliminarily manufactured, and a laminate of a carbon plastic electrode, a current collecting mesh and the metal-insulator-integrated frame member is heat-pressed. By forming an integrated electrode part by the above, this electrode part is inserted into the hole of the insulating frame material with a packing interposed, and the two tightening end plates constituting the zinc-bromine battery are bolted, whereby Provided is a method for manufacturing a current-collecting electrode of a zinc-bromine battery in which an electrode portion and an insulating frame material are sealed in a liquid-tight manner.

[0022]

According to the current collecting electrode and the method of manufacturing the same, the electrode portion mainly composed of the carbon plastic and the metal-insulator integrated frame member and the insulating frame material are substantially formed as separate bodies. The sealing performance between the two is maintained by the tightening force of the bolt using the packing. Therefore, the occurrence of "warpage" of the current collecting electrode due to heat shrinkage or the like is prevented, and the leakage of the electrolytic solution due to such warpage, generation of cracks due to excessive bolt tightening, and breakage of the electrode portion and the insulating frame material. Is obtained.

In addition, a relatively thick metal is provided in the electrode portion.
Since the insulator-integrated frame member is interposed, the mechanical strength of the obtained current collecting electrode itself is increased, and the effect of reducing the fatigue rupture due to the alternating application of positive pressure and negative pressure to the current collecting electrode. There is.

By using a stainless steel plate in place of the iron plate constituting the metal-insulator integrated frame member, in addition to the above-mentioned effects, current collection by bromine contained in the electrolyte due to the corrosion resistance of the stainless steel plate itself. Electrode corrosion is effectively prevented.

Also, while a plurality of bolts projecting from the predetermined position of the iron plate to the rear side are provided,
By forming a nut hole into which the above-mentioned bolt can be screwed, the electrode portion is inserted into the hole portion 17 of the insulating frame material via a packing, and the bolt is screwed into the nut hole, so that the current collecting electrode is formed. Itself is fixed by bolts and nut holes,
The effect is obtained that the desired sealing property is ensured on the current collecting electrode itself.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, various embodiments of a current collecting electrode of a zinc-bromine battery according to the present invention will be described in detail by assigning the same reference numerals to the same components as those shown in FIG. Will be described.

FIG. 1 is an exploded sectional view of a main part showing a first embodiment of a current collecting electrode 7 according to the present invention. 15a, 15 in the figure
Reference numeral a denotes two carbon plastic electrodes having a thickness of 1 mm. A current collecting mesh 6 made of brass is arranged on the back side a of the carbon plastic electrodes 15a, 15a. A 1 m carbon plastic electrode 15b is arranged.

The above carbon plastic electrode 15
The metal-insulator-integrated frame member 18 which is a characteristic component of the present invention is disposed on the back side a of b, and the back side a of the metal-insulator-integrated frame member 18 is made of Teflon. The packing 19 and the insulating frame material 16 are arranged. or,
The terminal piece 6a taken out of the current collecting mesh 6 is made of carbon plastic 15b, a metal-insulator integrated frame member 18,
It is guided to the outside of the insulating frame member 16 through a hole previously opened in the packing 19 and the insulating frame member 16.

The concrete structure of the above-mentioned metal-insulator integrated frame member 18 will be described with reference to the plan views shown in FIGS. That is, the metal-insulator integrated frame member 18 is
An insulating frame 21 located at an outer peripheral portion;
It is composed of an iron plate 22 having a large number of holes 22a and a insulator 23 which is integrally welded in a state filled in the holes 22a. In the embodiment, the thickness of the metal-insulator integrated frame member 18 is 5 mm or more.

Prior to assembling the current collecting electrode 7, the metal-insulator-integrated frame member 18 is provided with an iron plate 22 having a hole 22a opened in the frame 21 in advance. Is filled with the insulator 23 in the hole 22a of
It is preliminarily manufactured by performing a heat press at about 50 ° C. and about 55 kg / cm ² so as to be integrally welded.

At the time of assembling the current collecting electrode 7, first, in order to manufacture an electrode portion, using a metal mold (not shown), the carbon plastic electrodes 15 a, 15 a, the current collecting mesh 6, and the metal-insulator integrated frame member 18. And carbon plastic 15b, and heat-pressing means, for example, 150 ° C. to 180 °
The molding is performed integrally at a temperature of 55 ° C. and a pressing pressure of 55 kg / cm ² .

Next, the above-mentioned electrode portion is inserted into the hole portion 17 of the insulating frame member 16 with the packing 19 interposed therebetween, whereby the current collecting electrode 7 according to the first embodiment of the present invention is obtained. When assembling the obtained current collecting electrode 7 to the battery main body, a bolt (not shown) passed between the tightening end plates 8, 8 located outside the pair of laminated end plates 9 shown in FIG. Thereby, the electrode portion and the insulating frame member 16 are sealed in a liquid-tight manner, and the hermeticity with respect to the electrolytic solution is kept good.

Therefore, according to the first embodiment, the electrode portion mainly composed of the carbon plastic electrodes 15a and 15b and the metal-insulator integrated frame member 18 and the insulating frame member 16 are substantially separate bodies. It is a great feature that the sealing performance between the two is maintained by the tightening force of the bolt using the packing 19.

According to the current collecting electrode 7, since the electrode portions having different coefficients of thermal expansion and the insulating frame member 16 are separate bodies,
The occurrence of the "warp" phenomenon of the current collecting electrode 7 due to heat shrinkage or the like is prevented, and the leakage of the electrolytic solution due to such "warp", the generation of cracks due to excessive bolt tightening, the electrode portion and the insulating frame are prevented. The effect that the material is not broken can be obtained. In addition, by adopting Teflon as the packing 19, the corrosion resistance against the electrolytic solution containing bromine can be enhanced.

The metal-insulator-integrated frame member 18 is made of carbon plastic since the insulator 23 is filled in the hole 22a of the iron plate 22 arranged inside the frame 21 and is integrally welded. Interfacial adhesion with the electrode
With the presence of the iron plate 22, the carbon plastic 15a,
Good weldability with 15b.

Further, it is considered that the "warpage" occurs due to the difference in thermal expansion coefficient between the carbon plastics 15a and 15b constituting the electrode portion and the iron plate 22 constituting the metal-insulator integrated frame member 18. In such a case, the thickness of the iron plate 22 is
By making the thicknesses a and 15b larger than the thickness, the thermal expansion of the carbon plastic electrodes 15a and 15b is absorbed by the iron plate 22, and the warpage is prevented from occurring.

Further, a relatively thick metal is provided in the electrode portion.
Since the insulator-integrated frame member 18 is interposed, the thickness of the obtained current collecting electrode 7 itself becomes 8 mm or more. As the thickness increases, the mechanical strength increases and the built-in iron plate 22 increases the overall strength. This is also useful from the viewpoint of reducing the fatigue rupture caused by alternately applying positive pressure and negative pressure by the pump to the current collecting electrode 7.

Next, a second embodiment of the present invention will be described. Although the basic structure is the same as that of the first embodiment, the second embodiment is characterized in that a stainless steel plate is used instead of the iron plate 22 shown in FIGS. Then, similarly to the first embodiment, an insulating frame 21 is provided at a position surrounding the stainless steel plate.
And a large number of holes 22 opened in the stainless steel plate.
a is filled with the insulator 23 and welded together by a heat press means to obtain an electrode portion. Other configurations and assembling methods are the same as those of the first embodiment.

According to the second embodiment, the "warp" phenomenon of the current collecting electrode 7 due to the thermal shrinkage of the stainless steel plate and the carbon plastics 15a and 15b is prevented, and the leakage of the electrolytic solution and the bolts are prevented. The same effect as in the first embodiment that cracks are not generated or broken due to tightening is obtained, and since the stainless steel itself has higher corrosion resistance than the iron plate, corrosion of the current collecting electrode due to bromine contained in the electrolytic solution is caused. Is effectively prevented.

Next, a third embodiment of the present invention will be described with reference to FIGS. Since the basic configuration is the same as that of the first embodiment, the same reference numerals are given and displayed.

That is, 15a and 15a are carbon plastic electrodes, 6 is a current collecting mesh made of brass, and a carbon plastic electrode 15b is disposed on the back side a of the current collecting mesh 6. On the back side a of the carbon plastic electrode 15b, a metal-insulator integrated frame member 18a having a structure similar to that of the above-described example is arranged.

The metal-insulator integrated frame member 18a is
As shown in the liquid-contact side plan views of FIGS. 3 and 4 and the rear-side plan view of FIG. 5, an insulating frame 21 located on the outer peripheral portion;
An iron plate 22 at a position surrounded by the frame 21 and having a large number of holes 22a opened, and an insulator 23 integrally welded in a state of being filled in the holes 22a.
And a plurality of bolts 24 (four in the illustrated example) projecting from the predetermined position of the iron plate 22 in the direction of the back side a.

Reference numeral 19 denotes a Teflon packing disposed on the back side a of the metal-insulator-integrated frame member 18a, and reference numeral 16 denotes an insulating frame member disposed on the back side a of the packing 19.
At predetermined positions of the insulating frame member 16, the bolts 24, 2
Nut holes 25, 25 into which the screw 4 can be screwed are formed.

According to the third embodiment, the carbon plastic electrodes 15a, 15a, the current collecting mesh 6, the metal
Insulator-integrated frame member 18a and carbon plastic 1
5b are laminated, and an electrode part integrally formed by heat press means is obtained. Then, this electrode part is inserted into the hole 17 of the insulating frame member 16 with the packing 19 interposed therebetween, and the bolts 24, 24
Is screwed into the nut holes 25, 25 to obtain the integrally fixed current collecting electrode 7. Therefore, in the third embodiment, the current collecting electrode 7 itself has the bolts 24 and 24 and the nut holes 2.
The current collecting electrode 7 itself has a characteristic that a desired sealing property is secured. The operation and operation when assembling the obtained collecting electrode 7 to the battery body are the same as those in the first embodiment.

Next, a fourth embodiment of the present invention will be described. Although the basic configuration is the same as that of the third embodiment, the fourth embodiment is characterized in that a stainless steel plate is used instead of the iron plate 22 employed in the third embodiment.

According to the fourth embodiment, the "warp" phenomenon of the current collecting electrode 7 due to the heat shrinkage of the stainless steel plate and the carbon plastics 15a and 15b is prevented, and the leakage of the electrolytic solution and the bolts are prevented. In addition to the effect of preventing the occurrence of cracks and breakage due to tightening, the corrosion resistance of the stainless steel itself works effectively, and the corrosion of the current collecting electrode due to bromine can be prevented.

[0047]

As described above in detail, the current-collecting electrode of the zinc-bromine battery according to the present invention has an electrode portion mainly composed of a carbon plastic and a metal-insulator integrated frame member;
Because the insulating frame material is configured as a substantially separate body,
The sealing force between the bolts is maintained by the tightening force of the bolts with the packing interposed, and the occurrence of "warpage" of the current collecting electrode due to heat shrinkage and the like is eliminated, and leakage of the electrolyte and excessive bolt tightening are caused. The effect that cracks are not generated and the insulating frame material is not broken is obtained. In addition, since the relatively thick metal-insulator-integrated frame member is interposed in the electrode portion, the mechanical strength of the obtained current collecting electrode itself is increased, and the positive and negative pressures on the current collecting electrode are increased. The effect of reducing the fatigue rupture due to the alternate application of.

On the other hand, by using a stainless steel plate instead of the iron plate constituting the metal-insulator integrated frame member, the corrosion resistance of the stainless steel plate itself causes corrosion of the current collecting electrode due to bromine contained in the electrolytic solution. Can be prevented, and a plurality of bolts projecting from the predetermined position of the iron plate to the back side,
With the nut hole drilled at a predetermined position in the insulating frame material, the bolt is screwed into the nut hole after inserting the electrode portion into the hole portion of the insulating frame material with the packing interposed between The effect that the sealing property of this is ensured is obtained.

Therefore, according to the present invention, the warping phenomenon caused by the heat shrinkage of the collecting electrode and the cause of the characteristic failure such as the leakage of the electrolytic solution caused by the warping phenomenon are eliminated, and the mechanical strength is reduced. An enhanced zinc-bromine battery collector electrode is provided.

[Brief description of the drawings]

FIG. 1 is an exploded cross-sectional view showing a main part of a first embodiment of a current collecting electrode according to the present invention.

FIG. 2 is a plan view on the liquid contact side of a metal-insulator integrated frame member 18 which is a component of FIG.

FIG. 3 is an exploded cross-sectional view showing a main part of a second embodiment of the current collecting electrode according to the present invention.

4 is a plan view on the liquid contact side of a metal-insulator-integrated frame member 18a that is a component of FIG. 3;

FIG. 5 is a rear plan view of a metal-insulator integrated frame member 18a that is a component of FIG. 3;

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

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

FIG. 8 is a cross-sectional view of a main part showing a structural example of a conventional current collecting electrode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 6 ... Current-collecting mesh 6a ... Terminal piece 7 ... Current-collecting electrode 15a, 15b ... Carbon-plastic electrode 16 ... Insulating frame material 17 ... Hole 18, 18a ... Metal-insulator integrated frame member 19 ... Packing 21 ... Frame 22 ... Iron plate 22a ... Hole 23 ... Insulator 24 ... Bolt 25 ... Nut hole

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-62-17956 (JP, A) JP-A-58-197671 (JP, A) JP-A-57-119480 (JP, A) JP-A-59-119480 5565 (JP, A) JP-A-1-187762 (JP, A) JP-A-6-60055 (JP, U) JP-A-6-15264 (JP, U) JP-A-6-20701 (JP, U) Hikaru Hei 3-26965 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01M 4/86-4/96 H01M 12/08

Claims (4)

(57) [Claims] 1. A single cell is formed by laminating a separator plate on a rectangular flat intermediate electrode, and a plurality of the single cells are stacked to form a battery body. In the current-collecting electrode of a zinc-bromine battery in which the power electrode and the fastening end plate are arranged and the two fastening end plates are A metal-insulator-integrated frame member composed of an insulator filled and welded in a number of holes opened at appropriate positions on an iron plate surrounded by the frame, and a metal-insulator-integrated frame member and carbon A collector for a zinc-bromine battery, wherein a plastic electrode and a current collecting mesh are laminated and an electrode part integrally formed by heat press means is inserted into a hole of an insulating frame material with a packing interposed therebetween. Electrode. 2. A method according to claim 1, wherein a plurality of bolts projecting rearward from a predetermined position of the iron plate are provided, and a nut hole into which the bolt can be screwed is formed at a predetermined position of the insulating frame material. The current collecting electrode of the zinc-bromine battery according to claim 1. 3. The current-collecting electrode for a zinc-bromine battery according to claim 1, wherein a stainless steel plate is used in place of the iron plate. 4. An iron plate or a stainless steel plate having a hole opened inside the frame body, an insulator is filled in the hole of the iron plate or the stainless steel plate, and heat press means using a mold is used. A metal-insulator-integrated frame member integrally welded is preliminarily manufactured, and an electrode portion is formed by integrating a carbon plastic electrode, a current collecting mesh, and a laminate of the metal-insulator-integrated frame member by heat pressing means. hand,
This electrode portion is inserted into the hole of the insulating frame material with a packing interposed therebetween, and both the fastening end plates constituting the zinc-bromine battery are bolted together, so that the electrode portion and the insulating frame material are liquid-tightly sealed. A method for producing a current-collecting electrode for a zinc-bromine battery, wherein the current-collecting electrode is sealed.