JPS5986164A - Redox flow type cell - Google Patents

Abstract

PURPOSE:To maintain concentration of redox aqueous solution at desired level by providing mechanism for mixing redox aqueous solution in main and sub tank and feeding to flow type battery jar. CONSTITUTION:Sub-tanks 2 having capacity of 1/10-1/20 are provided at inside and outside of main tank 1, and at initial charging stage only liquid 3 (iron compound hydrochloric acid solution, for example) from said sub-tank 2 is circulated from a line mixer 4 through pump 5 and flow type battery jar 6. When liquid of concentration of 0.4mol/l is fed through pump 5 to said jar 6, concentration of liquid discharged from said jar 6 through charging reaction will be 0.5mol/l and never vary even when returned to sub-tank 2. The liquid will overflow to main tank 1 by the amount corresponding to flow from main tank 1 to increase concentration of liquid in main tank 1 gradually. Consequently concentration of liquid in said jar 6 will be stable for long term.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to redox flow type batteries, and particularly to storage and supply of redox aqueous solutions.

Electrical engineering for redox flow batteries is defined by combining two types of redox systems as positive and negative active material liquids. During charging and charging of these batteries, changes in the concentration of redox water (A) greatly affect the power efficiency of the system, especially regarding overvoltage during charging and tit electrode reaction rate during discharging. There is a period of low output in the early stage of discharge, which reduces the overall efficiency of this system in continuous operation, and also has the drawback of interfering with connection to commercial power during discharge.

In order to eliminate such drawbacks, the present invention has made it possible to maintain the concentration of the redox aqueous solution supplied to the flow-through type battery tank at a constant desired value by using a main tank and a sub-tank.

The present invention will be explained below with reference to illustrated embodiments.

FIG. 1 shows changes in the concentration of the redox aqueous solution in the battery tank during charging and discharging in a normal one-stack/one-tank system. For example, if the charging and discharging time is 6 hours each, there are approximately 1 hour low output time periods at the beginning of charging and at the end of discharging.

FIG. 2 shows changes in the concentration of the redox aqueous solution in the flow-through type battery tank of the present invention.

FIG. 3 is a schematic diagram of a redox flow battery showing one embodiment of the present invention.

In Figure 3, for example, the main tank supervisor's internal and external contents jLI
A sub-tank 2 of /lo to l/20 is provided, and at the initial stage of charging, only the liquid 3 (for example, an iron compound hydrochloric acid aqueous solution) in this sub-tank 2 is distributed from the mixing tank or line mixer 4 to the pump 5 and the pump 1. It is circulated through the type battery tank 6. After about 15 minutes (3 cycles), the concentration of liquid 3 in sub tank 2 will be 0.
．． Increase to 5 mol / l. From this time onwards, from the secondary tank 2G and the main tank 1, g, smol/l liquid O, 2
moA! / l of liquid 7 to the flow rate adjustment valve 8 (2:1)
The mixture is supplied to mixing tank 4 at the ratio of 0.4 m
The OL/E liquid is passed through the pump 5 and flows into the flow-through type battery tank 6.

Thereafter, due to the charging reaction, the concentration of the liquid discharged from the flow-through type 7b tank 6 gradually increases to 0.510.times.17 g. Therefore, the concentration of the liquid in the flow-through battery tank 6C remains stable for a long period of time as shown in FIG. In this way, the initial charging period during which the battery output decreases can be shortened and power efficiency can be improved.

It goes without saying that the same effect can be obtained by using the main and auxiliary tanks to shorten the period during which the battery's output decreases in the early stage of discharge, improve power efficiency, and maintain stable output for a long period of time.

In addition, in FIG. 3, the main tank 9 and its liquid 10
, sub-tank 11 and its liquid 12, and other adjustment valves 8
', mixing tank 4', and pump 5' correspond to the already explained main tank 1 and its liquid 7, sub tank 2 and its liquid 3, other adjustment valves 8, mixing tank 4, and pump 5, and this system is It is a redox aqueous solution (for example, a hydrochloric acid aqueous solution of a chromium compound) that forms the battery, and the principle of operation is the same, it produces the same effect, and it aims to improve the power efficiency of the total battery system. be.

As mentioned above, as a measure to improve the power efficiency of redox flow batteries, it is not only effective to keep the circulating redox aqueous solution at a constant level of 16 degrees by providing one sub tank outside the main tank, but also to improve the power efficiency of redox flow batteries. , just 1/1 of the main tank
A capacity of 10 to 20 l/20 is sufficient, installation is easy, plant costs are low, long-term stable battery discharge output is guaranteed, connection to external commercial power system is stable during discharge, etc. It has great value.

[Brief explanation of the drawing]

Figure 1 is a characteristic diagram of the concentration change of the redox aqueous solution in the battery tank due to charging and discharging of a normal redox flow type battery. FIG. 3 is a schematic diagram of a lead/tux flow type battery showing one embodiment of the present invention. 1 is the main tank, 2 is the sub tank, 3 is the redox aqueous solution,
4. 4' is a mixing tank or line mixer, 6
7 is a flow-through battery tank, 7 is a Redox aqueous solution, 8.8I is a flow rate adjustment valve, 9 is a main tank, IO is a redox aqueous solution, 11 is a sub tank, 12 is a redox aqueous solution Figure 1 Figure 2 Time (hi)

Claims (1)

[Claims] In a redox flow type battery, a redox aqueous solution stored in a tank is supplied to a flow-type battery tank using a pump to perform oxidation-reduction and charge/discharge.The tank consists of a main tank and a sub tank, and the redox aqueous solution in each tank is adjusted to the appropriate level. A redox flow type battery characterized by comprising a mechanism for mixing the mixture with the liquid and supplying the mixture to a flow type battery tank.