JPH0680262U - Current collector for zinc-bromine battery - Google Patents

Abstract

(57) [Abstract] [Purpose] Preventing "warpage" of the collector electrode due to thermal stress and external force and increasing bending strength, maintaining good water-tightness of electrolyte and improving battery performance. Provided is a collector electrode of a zinc-bromine battery. [Structure] The current collecting electrode 7 is configured by arranging the current collecting mesh 6 inside the laminated carbon plastic electrodes 15c and 15d and integrating them based on a heat pressing means under a predetermined temperature and pressure condition. . An insulating layer obtained by cutting off the manifold portion is welded to one surface of this carbon plastic electrode, and a hollow cylinder made of an insulating material is formed in a hole opened in the manifold portion of the carbon plastic electrode during manufacturing. The shape joint is inserted and fixed in a liquid-tight state.

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 to the storage tank as an oily precipitate, and at the time of discharging it is pumped into the unit cell. It is inserted 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 dendrites on the negative electrode zinc side and promoting uniform electrodeposition. And 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 to the negative electrode and reacting with zinc.

This zinc-bromine battery mainly has a bipolar type electrode, a battery body in which a plurality of cells (cells) are electrically stacked in series, an electrolytic solution storage tank, and an electrolytic solution storage tank 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 main body that constitutes the above zinc-bromine battery. 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, the positive electrode manifold 10 formed at the upper and lower two corners of the frame 2 a of each intermediate electrode 1 and 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% and a total energy efficiency of about 70% in a 50 KW class battery.

On the other hand, as shown in FIG. 7, the collector electrode 7 has a carbon plastic electrode 15 and a brass collector mesh 6 which are sequentially stacked on the insulating frame 16 to have a predetermined temperature and pressure. It is integrally manufactured based on the heat pressing means under the conditions. Reference numeral 6a denotes a terminal piece for extracting electric power, which is led out from the current collecting mesh 6, and this terminal piece 6a is taken out through a slit 16a formed in the insulating frame 16.

Usually, in order to manufacture the above-mentioned current collecting electrode 7, on the sheet-like insulating frame members 16b, 16b stacked as shown in FIG. 8, a hole portion having the same thickness as the insulating frame member 16b is formed. A plurality of insulating frame members 16c, 16c in which 17 is frame-shaped are laminated, and a carbon plastic electrode 15a, a brass current collecting mesh 6 and a carbon plastic electrode 15b are placed in the hole 17. They are sequentially assembled in a sandwich form, and are manufactured integrally by using a die (not shown) based on heat pressing means under predetermined temperature and pressure conditions. At the time of assembling to the battery body, the terminal piece 6a for taking out electric power derived from the current collecting mesh 6 is led out to the outside through the carbon plastic 15a and the insulating frame member 16b, and is connected to a current collecting bus bar (not shown). It is connected. The arrow A in FIG. 8 indicates the liquid contact side, and the arrow B indicates the back side.

[0011]

[Problems to be solved by the device]

 However, in the structure of the current collecting electrode 7 used in such a conventional zinc-bromine battery, the "warping" phenomenon is apt to occur in the current collecting electrode 7 when the temperature is lowered after molding by the heat pressing means, and There is a problem in that the above-mentioned “warpage” may occur due to the force applied from the device and the flatness of the current collecting electrode may be reduced.

That is, the conventional collecting electrode 7 has different thermal expansion coefficients in the thickness direction from the carbon plastic electrodes 15a and 15b, the collecting mesh 6 and the insulating frame members 16b and 16c, which are the constituent members. In addition, due to the difference in the structure and material between the liquid contact side A and the back surface side B of the current collecting electrode 7, the shrinkage rate of each material when the temperature is lowered naturally also differs, so that the obtained current collecting electrode is likely to bend. It is in a state.

Therefore, when such a collecting electrode 7 is assembled to the battery body and bolted and then the operation of the battery is started, the flatness of the collecting electrode 7 itself is lowered due to thermal stress or external force. There is a problem that the electrolyte leaks and the stored electric power is lost.

Further, a means for increasing the tightening force of the bolt passed between the tightening end plates 8 and 8 shown in FIG. 6 in order to enhance the sealing property is also considered, but if the bolt is excessively tightened, When applying a force, there is a problem that stress destruction occurs in other integrally laminated components.

On the other hand, the insulating frame members 16b and 16c are made of high-density polyethylene mixed with an inorganic filler, and there is a foreign surface between the insulating frame members 16b and 16c and the carbon plastic that is the material of the electrode portion, so that mechanical There is a problem that the resistance to pulling and bending is weak. In particular, when the battery is in operation, the electrolyte is circulated. At this time, the pressure applied to the collector electrode 7 may change and a bending force may be applied. When such a force is repeatedly applied, cracks may occur at the interface. This causes a problem that liquid leakage is likely to occur.

The present invention has been made in view of the above points, and eliminates a warp phenomenon of a current collecting electrode and a cause of a characteristic defect such as electrolyte leakage due to the warp phenomenon, which eliminates the cause of the battery. It is an object of the present invention to provide a current collecting electrode for a zinc-bromine battery that can improve performance.

[0017]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention forms a battery body by forming a single cell by stacking a separator plate on a rectangular flat plate-shaped intermediate electrode and stacking a plurality of the single cells. A collector electrode having a collector mesh, a pair of tightening end plates and a laminated end plate for pressing located inside the tightening end plates are arranged at both ends of the main body. In a current collector electrode of a zinc-bromine battery that is integrally laminated and fixed by tightening bolts, the current collector electrode has a current collecting mesh disposed inside the laminated carbon plastic electrode, and the current is kept at a predetermined temperature. The structure is integrated based on the heat press means under pressure conditions.

An insulating layer obtained by cutting out a manifold portion is welded to one surface of the carbon plastic electrode, and a hole formed in the manifold portion of the carbon plastic electrode is made of an insulating material. A hollow cylindrical joint is inserted and fixed in a liquid-tight manner.

[0019]

[Action]

 According to such a current collecting electrode, since only the carbon plastic electrode is used as the material of the current collecting electrode, the liquid contact side and the back side of the current collecting electrode have the same structure, and therefore the difference in thermal expansion coefficient is caused. For example, the “warp” phenomenon of the collector electrode due to the difference in shrinkage ratio of each material when the temperature is lowered does not occur, and the electrolyte leakage due to the decrease in flatness is prevented. Furthermore, since there is no interface due to foreign matter in the electrode material, the resistance to mechanical tension and bending becomes strong, and cracks do not occur even if the pressure applied to the current collecting electrode changes during circulation of the electrolyte. .

When the obtained collecting electrode is laminated on other members constituting the battery main body and tightened and fixed by using bolts, the water-tightness of the carbon plastic electrode is improved and the sealing property of the electrolyte is improved. Is sufficiently retained, and the performance as a battery can be improved.

[0021]

【Example】

 An embodiment of a current collecting electrode of a zinc-bromine battery according to the present invention will be described below in detail with reference to the drawings, in which the same reference numerals are given to the same components as the conventional components.

In the structure of the collecting electrode 7 shown in FIG. 1, 15c is a carbon plastic electrode having a thickness of approximately 3 mm, 15d is a carbon plastic electrode having a thickness of approximately 1 mm, and a brass-made electrode 15c is provided between the carbon plastics 15c and 15d. The current collecting mesh 6 of is arranged.

Then, a current collecting electrode 7 is obtained by using a die (not shown) and integrating them by a heat pressing means under a predetermined temperature and pressure condition. At the time of assembling to the battery main body, the terminal piece 6a for taking out the electric power, which is led out from the current collecting mesh 6, is led out to the outside through the inside of the carbon plastic 15c, and is connected to the current collecting bus bar not shown. The arrow A in FIG. 1 indicates the liquid contact side of the collector electrode 7, and the arrow B indicates the back side.

The present embodiment is structurally characterized in that substantially only the carbon plastic electrode is used as the material of the collecting electrode. In other words, the structures of the current collecting electrode 7 on the liquid contact side A and the back surface side B are made of the same material except for the current collecting mesh 6.

2 (A) and 2 (B) show the structure of the current collecting electrode 7 when it is assembled to the battery main body, and the insulating property of the hole portion 10a serving as the manifold is maintained and the inside of the battery main body is maintained. In order to insulate the channel (see FIG. 6), an insulating layer 18 made of polyethylene resin or the like in which the hole 10a is cut off is welded to one surface of the carbon plastic electrode portion 15e.

In order to confirm the occurrence of “warpage” of the obtained current collecting electrode 7, the current collecting electrode 7 obtained in this example and the conventional current collecting electrode 7 (see FIGS. 7 and 8) were examined. After each molding, it was sandwiched by a large aluminum plate (thickness of about 3 mm), a weight of 50 kg was applied for 24 hours, and it was left in a free state for 24 hours. The amount of warpage of the electrode 7 was measured. For the measurement, as shown in FIG. 4, the collecting electrode 7 was placed on the surface plate 20 and the measured value X by the hide gauge 25 was used.

As a result, the average X measurement value of the conventional collector electrode was 27.2 mm, whereas the average X measurement value of the collector electrode 7 obtained in this example was 2.3 mm. , "War" was confirmed to be remarkably improved.

5 (A), (B), (C), and (D) are schematic views showing a specific manufacturing process of the present invention. First, as shown in FIG. 3A, a carbon plastic electrode 15f having a built-in current collecting mesh 6 is manufactured in advance by using press molding means. From the current collecting mesh 6, a terminal piece 6a is led out to the back side. Next, as shown in FIG. 3B, holes 10a 1 and 10a 2 are opened in the portion of the carbon plastic electrode 15f which will be the manifold portion.

Next, as shown in FIG. 3C, hollow cylindrical joints 21 and 21 made of an insulating material are inserted into the holes 10a and 10a in a liquid-tight state with an O-ring 22 interposed therebetween. Then, as shown in FIG. 3D, a nut 23 is screwed and fixed to the threaded portions 21a, 21a of the cylindrical joint 21. Then, in the place where the conventional insulating frame portion was present, the insulating layer 18 is formed by adhering a material in which a fluorine-based grease is applied to a polyethylene sheet.

The current collecting electrode for a zinc-bromine battery according to this example is manufactured in this manner, and the current collecting electrode obtained according to this example has “warpage” caused by a difference in thermal expansion coefficient. It was confirmed that there is a significant difference from the conventional collector electrode in terms of ease of production.

[0031]

[Effect of device]

 As described in detail above, since the current collecting electrode according to the present invention uses substantially only carbon plastic electrodes as the material of the current collecting electrode, the structure on the liquid contact side and the back surface side of the current collecting electrode is It is the same, and the "warpage" phenomenon caused by the difference in shrinkage ratio of each material when the temperature drops after molding by the heat press means does not occur, and the flatness as a current collecting electrode can be maintained. it can.

In particular, since the carbon plastics, which is the material of the electrode part, does not have an interface due to foreign matter, the resistance to mechanical pulling or bending is increased, and when the electrolyte is circulated during operation of the battery, current collection is performed. Even if the pressure applied to the electrode changes and the bending force is repeated, there is no risk of cracks at the interface or power loss due to liquid leakage.

According to the present invention, the warping phenomenon of the current collecting electrode and the cause of characteristic defects such as liquid leakage of the electrolyte due to the warping phenomenon are eliminated, and the obtained current collecting electrode constitutes the battery body. When laminated on another member and fastened with bolts, the water-tightness of the carbon plastic electrode becomes good and the electrolyte sealing property is sufficiently retained, which improves the battery performance. it can.

Further, since the structure of the current collecting electrode itself is simplified, the production is facilitated, the cost is reduced, and the possibility that voids or the like are generated in the electrode is eliminated, resulting in a high yield and a component. Can improve the quality of.

[Brief description of drawings]

FIG. 1 is an exploded cross-sectional view of main parts for explaining a specific embodiment of the present invention.

FIG. 2 (A) is a side sectional view of the obtained current collecting electrode. FIG. 2B is the same plan view.

FIG. 3 is a plan view showing measurement points of “warpage” in the present embodiment.

FIG. 4 is a schematic side view of a gauge for measuring the above “warpage”.

FIG. 5 is a schematic view showing a specific manufacturing process of the collector electrode according to the present embodiment.

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

FIG. 7 is a cross-sectional view of essential parts showing a structural example of a conventional collector electrode.

FIG. 8 is an exploded cross-sectional view of a main part showing an example of a conventional assembling structure of a collecting electrode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Intermediate electrode 1a ... Electrode part 1b ... Frame 3 ... Separator 4 ... Packing 5 ... Spacer mesh 6 ... Current collecting mesh 6a ... Terminal piece 7 ... Current collecting electrode 8 ... Tightening end plate 9 ... Laminated end plate 10 ... Positive electrode Manifold 10a ... Hole portion 11 ... Negative electrode manifold 12 ... Channel 13 ... Micro channel 15c, 15d, 15f ... Carbon plastic electrode 15e ... Carbon plastic electrode portion 20 ... Surface plate 21 ... Cylindrical joint 23 ... Nut 25 ... Hyde gauge

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuharu Namiki 2-1-1-17 Osaki, Shinagawa-ku, Tokyo Inside the Meidensha Co., Ltd.

Claims (3)

[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 at both ends of the battery main body,
By arranging a current collecting electrode having a current collecting mesh, a pair of tightening end plates and a laminated end plate for pressing located inside the tightening end plates, and bolting between the both tightening end plates. In a current collector electrode of a zinc-bromine battery that is integrally laminated and fixed, the current collector electrode has a current collecting mesh disposed inside a laminated carbon plastic electrode, and heat is collected under predetermined temperature and pressure conditions. A current collecting electrode for a zinc-bromine battery, characterized by being integrated based on a pressing means. 2. The current collecting electrode for a zinc-bromine battery according to claim 1, wherein an insulating layer obtained by cutting off a manifold portion is welded to one surface of the carbon plastic electrode. 3. A hollow cylindrical joint made of an insulating material is inserted and fixed in a liquid-tight state into a hole formed in the manifold portion of the carbon plastic electrode. 2. A zinc-bromine battery current collecting electrode according to claim 2.