JPS6316573A - Electrolyte tank of electrolyte flow type battery - Google Patents

Abstract

PURPOSE:To enhance the reliability on the leakage of an electrolyte which is important in comparison with a non-important electrolyte by housing a tank for the important electrolyte in a tank for the non-important electrolyte. CONSTITUTION:A tank 21 for a negative solution 17, that is an important electrolyte, is housed in a tank 22 for a positive solution 18, a non-important electrolyte. Even if the inside tank 21 breaks to cause the leakage, thus the important solution or negative solution 17 leaks out only in the outer tank 22. Since the negative solution 17 does not leak outside, the safety and reliability are widely facilitated without causing the leakage danger to the outside world.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an electrolyte tank for a flow-through electrolyte battery having a flow-through electrolytic cell.

[Prior art]

In this specification, the term ``important'' with respect to electrolytes refers to the fact that the electrolyte is highly dangerous or expensive, and thus would have a significant adverse effect if leaked, and ``non-important.'' ” indicates that the degree of adverse effect is small compared to “important” electrolytes.

BACKGROUND OF THE INVENTION Electrolyte flow type batteries are attracting attention as secondary batteries for power storage equipment in order to respond to fluctuations in power demand or to stabilize unstable power generation such as solar thermal power generation.

Here, an overview of the principle of a redox flow battery as an example of a flow-through battery will be explained using FIG. 2.

FIG. 2 shows the charging and discharging states of a power storage system using a redox flow battery.

In the figure, 1 is the power plant, 2 is the substation equipment, 3 is the load, and 4
5 is an inverter, 5 is a redox battery, and is composed of two tanks 6, 7, pumps 8 and 9, and a flow-through electrolytic cell 10. vM, the visible electrolytic cell 10 has a positive electrode 11 and a negative electrode 12,
and a diaphragm 13 separating both electrodes, the diaphragm 13
Is there a positive electrode in the left and right rooms separated by ? 1I14, negative electrode liquid 1
5 is accommodated.

The positive electrode liquid I4 is a hydrochloric acid solution containing Fe ions, and the negative electrode liquid 1 is a hydrochloric acid solution containing Fe ions.
5 shows an example in which a salt M solution containing Cr ions is used.

Next, the effect will be explained.

Electric power generated at the power plant 1 and transmitted to the substation equipment 2 is transformed to an appropriate voltage and supplied to the load 3.

On the other hand, when surplus power is generated at night, the inverter 4 performs AC/DC conversion and charges the redox battery 5. In this case, as shown in Fig. 2, the pump 8.9 is
Charging is performed while gradually circulating the negative electrode liquid 14,15. When Fe ions are used in the positive electrode solution 14 and C ions are used in the negative electrode solution 15, the reactions that occur in the flow-through electrolytic cell 10 are reactions on the charging side in equations +11 to (3) above.

In this way, electric power is accumulated in the positive electrode liquid 14 and the negative electrode liquid I5.

On the other hand, when the supplied power is less than the demanded power, the reaction on the discharge side in equations (11 to (3) above) is performed, the impark 4 performs orthogonal conversion, and the load is Power is supplied to 3.

[Problem that the invention seeks to solve]

Regarding the electrolyte tank of the flow-through type battery including the redox flow battery described above, when both the positive electrode and the negative electrode are electrolyte flow-type electrodes and an electrolyte tank is required for each electrolyte of the positive electrode and the negative electrode, Conventionally, separate tanks were provided for the positive electrode liquid and the negative electrode liquid.

If electrolytic solution leaks from these tanks, there is a risk that the electrolytic solution will directly leak into the room or premises where the tank is stationary.

In the case of the above-mentioned flow-through type battery, the positive and negative electrode liquids are different, and the price of the liquid, the danger of the leaked liquid, the difficulty of disposal, etc. depend on the battery active materials they contain. The importance of preventing leakage also differs. However, in conventional flow-through batteries, tanks with the same specifications are used in most cases, even if the positive and negative electrolytes are different electrolytes.
The same level of consideration is given to preventing electrolyte leakage.

For example, as shown in FIG. 3, the electrolyte tanks 21 and 22 each contain a hydrochloric acid solution of iron chloride as the positive electrode liquid 18 and a negative electrode liquid 17.
These are the positive and negative electrolyte tanks of a redox flow battery using a hydrochloric acid solution of chromium chloride. or,
Tanks 21, 22 are of the same specification. 19.20
is a pump.

When comparing the positive electrode solution 18 and negative electrode solution 17 of the redox flow battery shown in Fig. 4 with iron and chromium, which are the battery active materials contained in them, the price of chromium is currently higher than that of iron. Furthermore, due to the background of hexavalent chromium pollution, chromium would have a large impact on the public if it were to leak.Thus, the importance of preventing leakage is greater for the anode liquid 17 containing chromium ions. Regardless, in the case of Figure 4, the reliability of leakage for the negative electrode solution 17, which is an important electrolyte, and the positive electrode solution 18, which is a non-important electrolyte, is the same, and leakage from the tank does not occur for either solution. If this happens, the electrolyte will leak into the room or onto the premises.

Therefore, if the negative electrode liquid 17, which is an important electrolyte, leaks, there is a problem in that it will have a large effect on the surroundings, such as anxiety, and will also cause a large economic loss.

The present invention solves the above-mentioned problems in the conventional ones, and reduces leakage of important electrolytes (i M
It is an object of the present invention to provide an electrolyte tank for an electrolyte flow type battery that has improved performance and can be realized by a calendar-like structure.

c. Means for Solving Problems] The present invention, as a means for solving the above-mentioned problems of the conventional ones, supplies a positive electrode electrolyte and a negative electrode electrolyte respectively stored in tanks to a flow-through type electrolytic cell. In the electrolyte tank of an electrolyte flow type battery that performs charging and discharging, a tank containing an important electrolyte of higher importance is housed in a tank of another less important electrolyte. It is an object of the present invention to provide an electrolyte tank for an electrolyte flow type battery having the following characteristics.

[For production]

Since the present invention is constructed as described above, even if the important electrolytic solution of high importance stored inside leaks, it will only leak into the non-important electrolytic solution of low importance outside. , it is possible to prevent danger without leaking to the outside world. Furthermore, the important electrolyte that has leaked into the non-important electrolyte can be separated and recovered, so the expensive important electrolyte can be reused.

In addition, there is one tank each for the positive and negative electrode electrolytes,
In the case of one tank 2, where the electrolyte is circulated, the liquid level in both tanks does not change, so if you keep the liquid levels inside and outside almost the same, there will be a wall between the inner and outer tanks containing the important electrolyte. Since the liquid pressures of the two are almost equal and balanced, it prevents large stress from occurring due to pressure differences, making it possible to create a tank with a relatively simple, lightweight structure and high strength, making it reliable against damage and leakage. You can increase your sexuality.

In the case of a two-tank system with two tanks each for positive and negative electrolytes, the outer tank for non-critical electrolyte is changed to the non-critical electrolyte on the side where the level increases or decreases in the same way as the level of the inner important electrolyte increases or decreases. If you select a liquid tank and combine it with this, you can get the same effect.

〔Example〕

To explain an embodiment of the present invention using the drawings, in FIG. 1, a tank 21 for the negative electrode solution 17, which is an important electrolyte, is accommodated in a tank 22 for the positive electrode solution 18, which is a non-important electrolyte. ing. The tank 21 is the tank 6a or 6b in FIG. 2, and the tank 22 is the tank 7a or 7 in FIG.
Corresponds to b.

Any combination of the inside and outside may be used, but if the tank 7b is housed in the tank 6a and the tank 7a is housed in the tank 6b in such a combination that the liquid level inside and outside increases and decreases in the same way, the wall of the tank 7a or 7b will be removed. The liquid level inside and outside is always almost the same, the pressure is balanced, and the tank 73 or 7b has a simple and lightweight structure, has a high proof strength, and is highly reliable.

In such a structure, even if the inner tank 21 is damaged and leaks, the negative electrode liquid 17, which is an important electrolyte, will only leak into the outer tank 22 and will not leak to the outside world. It poses no danger and is highly safe (highly reliable).

In the above embodiments, a redox flow battery was used as the flow-through type battery, but the present invention can be applied to all flow-through type batteries that require an electrolyte tank for each of the positive and negative electrode electrolytes. is possible.

In addition, positive electrode liquid and negative J! i? Even when the electrolytes fi and are the same, the present invention can be applied to reduce the possibility of electrolyte leakage throughout the system. This clearly reduces the possibility of leakage into the room or premises compared to the conventional case where separate tanks are provided, and furthermore, the importance of leakage prevention between the positive and negative electrode fluids is significantly reduced. If the electrolyte with a higher degree of leakage prevention is placed in the inner tank of a double tank, there is a possibility that the electrolyte with a higher degree of leakage prevention will leak into the room or onto the premises. This makes it relatively small, and has an extremely large practical effect.

[Brief explanation of the drawing]

Figure 1 is a detailed explanatory diagram of the present invention, Figure 2 is a redox
FIG. 3 is an explanatory diagram illustrating charging and discharging states of a power storage system using a flow battery, and FIG. 3 is an explanatory diagram of a conventional example. ■...Jun 1! Power supply, 2... Substation equipment, 3... Load, 4... Inverter, 5... Redox flow battery, 6.7... Tank, 8, 9... Pump, 1
0... Flow type electrolytic cell, 11... Positive electrode, 12... Negative electrode, 13... Separation 1, 14... Positive electrode liquid, 1... Negative electrode liquid, 17... Negative electrode liquid, l8... Positive electrode liquid, 19.2
0...pump, 21.22...tank.

Claims (1)

[Scope of Claims] 1. In an electrolyte tank of a flow-through electrolyte battery in which charging and discharging are performed by supplying a positive electrode electrolyte and a negative electrode electrolyte stored in the respective tanks to a flow-through electrolyte tank, the one with higher importance An electrolyte tank for an electrolyte flow type battery, characterized in that a tank for an important electrolyte is accommodated in a tank for a less important electrolyte. 2. There are two tanks each for the positive electrode electrolyte and two tanks for the negative electrode electrolyte, and the tank for the important electrolyte is placed in the tank for the non-important electrolyte whose liquid level increases and decreases at the same time. A tank according to claim 1 housed in a tank.