JP2595549Y2 - Sealed zinc-bromine battery - 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 sealed 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 a bromine complexing agent added to the electrolytic solution and returns as an oily precipitate to the positive electrode side storage tank. It is sent inside 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, and quaternary ammonium salts for preventing dendrite on the negative electrode zinc side and promoting uniform electrodeposition, and a bromine complexing agent. It is. 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]

[Chemical Formula 1] During charging: positive electrode: 2Br ⁻ → Br ₂ + 2e ⁻ , negative electrode: Zn ⁺⁺ + 2e ⁻ → Zn Discharging: positive electrode: 2Br ⁻ ← Br ₂ + 2e ⁻ , negative electrode: Zn ⁺⁺ + 2e ⁻ ← Zn It is represented by

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. The product of the number of layers of the intermediate electrode 1 and the separator plate 2 and the battery electromotive force is the battery voltage.

[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%.

FIG. 7 is a schematic diagram for explaining the operation principle of the zinc-bromine battery. In FIG. 7, reference numeral 14 denotes a positive electrode storage tank, and a positive electrode electrolyte 15 and bromine are stored in the positive electrode storage tank 14. The complex compound 16 is stored. Reference numeral 17 denotes a negative electrode storage tank in which a negative electrode electrolyte 18 is stored. The positive electrode electrolyte 15 is supplied to the positive electrode pump 19.
As shown in the figure, a single cell is circulated from the positive electrode manifold 10 of the battery body through the four-way valve 20 and returned to the positive electrode side storage tank 14 through the four-way valve 20, while the negative electrode electrolyte 18 is With the driving of the side pump 21, the gas flows from the negative electrode manifold 11 of the battery body through the single cell separated by the separator 3 and returns to the negative electrode storage tank 17.

[0012]

However, in such a conventional zinc-bromine battery, since the configuration of the battery itself is divided into an electrolyte storage tank, a battery main body, and a piping system, the electrolytic solution from a joint or the like is not used. There is a problem that the liquid leaks easily, a dead space between the components increases, and the apparatus becomes large.

That is, since this battery is structured to operate by circulating the electrolyte, there is a concern that liquid leakage may occur when the tightening pressure of the joints connecting the piping systems or the bolts with the bolts decreases. Also, in order to transport the positive electrode electrolyte and the negative electrode electrolyte, two pumps, a positive electrode side pump and a negative electrode side pump installed outside the battery body, are required,
Along with the problem of the dead space, there is a problem that a large amount of auxiliary equipment energy is required and the running cost is increased. Furthermore, since the electrolytic solution flows through the positive and negative electrode manifolds in the battery body, there is also a problem that the shunt current effect lowers Coulomb efficiency.

The present invention has been made in view of the above points, there is no leakage of electrolyte due to pipes or joints, the current efficiency can be increased, and the dead space between each component is minimized. It is an object of the present invention to provide a sealed zinc-bromine battery capable of reducing the size of the device.

[0015]

In order to achieve the above object, the present invention provides an electrode tank which is housed at an appropriate position in a sealed battery tank and has an electrolyte circulation hole formed in a bottom wall thereof, A pump for feeding the electrolyte storage area and the electrolyte to the electrode tank formed below the tank, and alternately inserted and disposed in the electrode tank, and an upper end protruding above the sealed battery tank; The sealed zinc-bromine battery is composed of a positive electrode side intermediate electrode and a negative electrode side intermediate electrode connected in parallel for each positive electrode and negative electrode and connected to a plus terminal and a minus terminal, respectively.

The intermediate electrode on the negative electrode side is supported by a substantially rectangular insulating frame, and a separator with a post is provided on both the front and back surfaces of the intermediate electrode while maintaining an appropriate gap. In order to supply zinc ions to the intermediate electrode on the negative electrode side, a porous film is used. Further, on both surfaces of the intermediate electrode on the positive electrode side, an active layer in which activated carbon fibers are adhered by a lamination process is formed.

[0017]

According to this sealed zinc-bromine battery, the electrode tank is housed in the sealed battery tank during assembly, and the negative electrode-side intermediate electrode and the positive electrode side intermediate electrode are inserted and arranged in this electrode tank. Then, the upper end of each of these intermediate electrodes is connected in parallel for each of the positive electrode and the negative electrode above the sealed battery tank, connected to the plus terminal and the minus terminal, respectively, and a predetermined amount of electrolyte is filled in the battery tank. Thus, the intended sealed zinc-bromine battery is completed.

Then, the electrolyte stored in the electrolyte storage area flows into the electrode tank with the driving of the pump, and returns to the electrolyte storage area through the electrolyte circulation hole. The generated bromine reacts with the bromine complexing agent added to the electrolyte to form an oily precipitate, which is returned to the electrolyte storage area through the electrolyte circulation hole, and is pumped into the electrode tank during discharge. Be reduced. Zinc ions are supplied to the intermediate electrode on the negative electrode side through a porous film formed on the separator, and the obtained power is taken out from the plus terminal and the minus terminal.

[0019]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view of a sealed zinc-bromine battery according to the present invention. FIG. 1 is a longitudinal sectional view of a main part showing a basic embodiment of a sealed zinc-bromine battery 40 according to the present invention. In the figure, reference numeral 22 denotes a sealed battery tank. The electrode tank 23 is stored on a support bracket 22a protruding from an appropriate position on a wall surface. Electrolyte circulation holes 23a, 23a are opened in the bottom wall of the electrode tank 23.

In the electrode tank 23, positive electrode-side intermediate electrodes 24 and negative electrode-side intermediate electrodes 25 are alternately inserted and arranged.
2 and are connected in parallel for each of the positive electrode and the negative electrode, and are connected to the plus terminal 26 and the minus terminal 27, respectively. In this embodiment, carbon plastic electrodes are used as the intermediate electrodes 24 and 25.

A space 31 is defined below the electrode tank 23 by a partition wall 28, and a pump 29 is provided in the space 31. A pipe 36 led out from the pump 29 extends upward through the support bracket 22a. Reference numeral 32 denotes an electrolyte solution storage area formed below the electrode tank 23, and the electrolyte solution stored in the electrolyte solution storage area 32 is sucked into the pump 29 from the suction pipe 30.

The specific structure of each of the above components will be described below. FIGS. 2A and 2B show the intermediate electrode 2 on the negative electrode side.
5, the intermediate electrode 25 is supported by a substantially rectangular insulating frame 33, and a separator 34 with a post 34a is disposed on both front and back surfaces of the intermediate electrode 25 with an appropriate gap therebetween. ing. The post 34a has a function of regulating the position of the separator 34 and maintaining the space formed between the post 34a and the intermediate electrode 25. The separator 34 uses a porous film for supplying zinc ions to the negative electrode-side intermediate electrode 25 as described later.

FIGS. 3A and 3B show the structure of the intermediate electrode 24 on the positive electrode side. Active layers 24a are attached to both surfaces of the intermediate electrode 24. FIG. As the active layer 24a, for example, a layer to which activated carbon fibers are attached by a lamination process is used.

FIG. 4 shows the structure of the electrode tank 23. The electrode tank 23 is formed of a box having an open top, and a plurality of electrolytes are provided on the bottom wall of the electrode tank 23 as described above. Circulation holes 23a, 23a are opened.

FIG. 5 shows the structure of the sealed battery tank 22 when the electrode tank 23 is removed. The upper wall of the battery tank 22 has the upper ends of the intermediate electrodes 24 and 25 sealed. Holes 35, 35 for projecting above the battery tank 22 are opened. The arrangement of the pump 29 and its attached parts is as described with reference to FIG.

The electrode tank 23 shown in FIG. 4 is housed in the sealed battery tank 22 shown in FIG. 5, and the negative electrode-side intermediate electrode 25 shown in FIGS. Of the intermediate electrodes 24 are inserted and arranged with respect to each other.
25 is connected in parallel for each of the positive electrode and the negative electrode above the sealed battery tank 22 and connected to the plus terminal 26 and the minus terminal 27, respectively, and the battery tank 22 is filled with a predetermined amount of electrolyte. Thus, the sealed zinc-bromine battery 40 according to the present embodiment is completed.

According to this configuration, the electrolyte stored in the electrolyte storage area 32 is supplied to the pipe 36 along with the driving of the pump 29.
And rises as shown by the arrow C in FIG.
Flows into. Then, after flowing through the electrode tank 23, it is returned to the electrolyte storage area 32 through the electrolyte circulation hole 23 a.

The usual components of the electrolytic solution are a ZnBr ₂ aqueous solution, a salt such as NH ₄ Cl for lowering the resistance, and P which promotes uniform electrodeposition by preventing dendrite on the zinc side of the negative electrode.
b, Sn, quaternary ammonium salts and a bromine complexing agent. Then, bromine generated at the positive electrode side intermediate electrode 24 at the time of charging reacts with the bromine complexing agent added to the electrolytic solution to form an oily precipitate from the electrolytic solution circulating hole 23a through the electrolytic solution storage area 3.
2 and is discharged into the electrode tank 23 by the pump 29 at the time of discharge to be reduced. Since the separator 34 is formed using a porous film, zinc ions are supplied to the intermediate electrode 25 on the negative electrode side through the porous film. The obtained electric power can be taken out from the plus terminal 26 and the minus terminal 27.

[0029]

As described in detail above, according to the sealed zinc-bromine battery of the present invention, the configuration of the battery itself is divided into a battery main body, a piping system, an electrolyte storage tank, and the like as in the conventional case. Therefore, even when used for a long period of time, the leakage of the electrolyte does not occur, and the dead space between the components is minimized, so that the apparatus can be miniaturized.

In addition, bromine generated at the positive electrode side intermediate electrode during charging reacts with the bromine complexing agent added to the electrolytic solution and is stored as an oily precipitate in the electrolytic solution storage area. Has the effect that almost no occurrence occurs.

Further, since only one pump for feeding the electrolyte is required, the space saving effect and the auxiliary equipment energy are minimized, and the running cost can be reduced. Further, since the electrolytic solution does not flow through the positive and negative electrode manifolds as in the related art, a decrease in Coulomb efficiency due to a shunt current effect is eliminated, and an effect of increasing battery efficiency is exhibited.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part showing an embodiment of a sealed zinc-bromine battery according to the present invention.

FIG. 2A is a front sectional view showing the structure of a negative electrode-side intermediate electrode according to the present embodiment. FIG. 2B is a side view thereof.

FIG. 3A is a front sectional view showing a structure of a positive electrode side intermediate electrode according to the present embodiment. FIG. 3B is a side view of the same.

FIG. 4 is a sectional view showing the structure of the electrode tank according to the present embodiment.

FIG. 5 is an essential part cross-sectional view showing the structure of the battery tank according to the embodiment.

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

FIG. 7 is a schematic diagram showing the operation principle of a zinc-bromine battery.

[Explanation of symbols]

 Reference numeral 22: sealed battery tank 23 ... electrode tank 23a ... electrolyte circulation hole 24 ... intermediate electrode (on the positive electrode side) 25 ... intermediate electrode (on the negative electrode side) 26 ... plus terminal 27 ... minus terminal 28 ... partition wall 29 ... pump 30 ... Suction pipe 32 ... Electrolyte storage area 33 ... Insulating frame 34 ... Separator 34a ... Post 35 ... Hole

Claims (4)

(57) [Scope of request for utility model registration] 1. A sealed battery tank, an electrode tank housed at an appropriate position in the sealed battery tank and having an electrolyte circulation hole opened in a bottom wall, and an electrolytic cell formed below the electrode tank. A liquid storage area and a pump for feeding the electrolytic solution to the electrode tank, and alternately inserted and disposed in the electrode tank, the upper end protruding above the sealed battery tank, and connected in parallel for each of the positive electrode and the negative electrode A sealed zinc-bromine battery comprising a positive electrode side intermediate electrode and a negative electrode side intermediate electrode connected to a positive terminal and a negative terminal, respectively. 2. The intermediate electrode on the negative electrode side is supported by a substantially rectangular insulating frame, and a post-mounted separator is disposed on both front and back surfaces of the intermediate electrode while maintaining an appropriate gap.
The sealed zinc-bromine battery according to the above description. 3. The sealed zinc-bromine battery according to claim 1, wherein a porous film is used as the separator to supply zinc ions to the intermediate electrode on the negative electrode side. 4. The sealed zinc-bromine battery according to claim 1, wherein an active layer having activated carbon fibers attached thereto by lamination is formed on both surfaces of the intermediate electrode on the positive electrode side.