JPS6369151A - Redox cell - Google Patents

Abstract

PURPOSE:To obtain a redox cell having high efficiency and large output by inserting a partition every tens of cells into cell stacks, and supplying and exhausting an electrolyte every partitioned cell stack. CONSTITUTION:In a substack 16, a positive solution and a negative solution are supplied to a positve chamber 20 and a negative chamber 22, which are partitioned with partitions 17, from a positive solution inlet manifold 32 and a negative solution inlet manifold 33 respectively. The positive solution and negative solution are gathered in a positive solution outlet 36 and a negative solution outlet 37 in a solution supply and exhaust part 23 through a positive solution outlet manifold 34 and a negative solution outlet manifold 35, and exhausted by a positive solution exhaust header 39 and a negative solution exhaust header 40 through a solution exhaust pipe 38. Electrical insulators are mounted to solution supply and exhaust pipelines.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a redox battery in which a large number of cells are stacked, and more specifically, a large number of cells are divided and partitioned into a plurality of stacked units, and each stacked unit is supplied and discharged. This invention relates to a redox battery that uses liquid.

[Conventional technology]

Electric power is easy to convert into various types of energy and easy to control.
Since there is no environmental pollution during consumption, the proportion of energy consumption is increasing every year. A unique feature of electricity supply is that production and consumption occur simultaneously. Within this constraint, the power industry is required to transmit high-quality power at a constant frequency and voltage with high reliability while responding quickly to fluctuations in power consumption, but in reality, the output is Nuclear power generation and new thermal power generation, which are difficult to change but have high efficiency, should be operated at the highest efficiency rating possible, and the large increase in daytime power demand should be covered by hydropower generation, etc., which are suitable for generating electricity in response to fluctuations in power consumption. Currently, surplus electricity is generated at night.

For this reason, pumped storage power generation is used to store surplus electricity at night from economically viable nuclear power generation and cutting-edge thermal power generation.
Location conditions for pumped storage power generation are becoming increasingly difficult.

Due to the above-mentioned circumstances, various types of secondary batteries have been researched as a method for storing electricity, which is a highly versatile energy without environmental pollution. Redox batteries are attracting attention.

An overview of this principle will be explained using Figure 9.
FIG. 9 shows a power storage system using a two-tank redox battery. In this figure, 1 is a power plant, 2 is substation equipment, 3 is a load, 4 is an inverter, 5 is a redox battery, and this redox battery 5 is a tank 6.
, a flow-through type electrolytic cell 8, and the like.

The flow-through electrolytic cell 8 is partitioned by a diaphragm 9, and has a positive electrode liquid chamber 1 inside.
0a and a negative electrode liquid chamber 10b are provided, the positive electrode liquid chamber 10a accommodates a positive electrode 11 and a positive electrode liquid, for example, a liquid such as a hydrochloric acid solution containing Fe ions, while the negative electrode liquid chamber 10b contains a negative electrode 12,
A pump 13a is provided between the tank 6 and the positive electrode chamber 10a, and a circulation path for the positive electrode is provided between the tank 6 and the positive electrode chamber 10a. 14, and also the tank 7 and the negative electrode liquid chamber +
A pump 13b is provided between Ob, and a negative electrode liquid circulation path 15 is formed between the tank 7 and the negative electrode liquid chamber 10b.

In the above configuration, power is generated at the power station 1, and the substation (12
The electric power transmitted to 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, charging is performed while the pumps 13a and 13b circulate the positive and negative electrode liquids through the positive electrode chamber +Oa and the negative electrode chamber 10b. For example, when Fe ions are used in the positive electrode solution and Cr ions are used in the negative electrode solution, the reactions that occur in the flow-through electrolytic cell 8 are reactions on the charging side in the following formulas +1) to (3).

Discharge Discharge In this way, electrical power is stored in the positive and negative electrolytes.

Next, if the supplied power is less than the demand power, pump I 32.13b pumps the positive and negative electrolytes into the positive and negative electrolyte chambers.
+1 while circulating through Oa and the negative electrode liquid chamber 10b.
Discharge is performed by the reaction on the discharge side in Equations 1 to (3), orthogonal conversion is performed by the inverter 4, and power is supplied to the load 3 via the substation equipment 2.

[Problem that the invention seeks to solve]

In the redox battery, the electromotive force per single cell is approximately 1
Since the voltage is low, it is necessary to connect the single cells in series to increase the voltage. However, in the single-pole connection method in which single cells are connected with busbars, the efficiency decreases significantly due to ohmic loss in a part of the busbar, so multi-pole A method is adopted in which the cells themselves are stacked using the formula connection method. This stacked electrolytic cell is called a stack. Each cell in the stack is in fluid communication through a manifold for supplying and discharging electrolyte, but because each cell has a different potential, ions flow through this channel according to the potential gradient, a so-called shunt current. This has the disadvantage that it generates a current due to this, resulting in electrical loss.

It is known that the electrical loss described above increases as the number of stacked cells increases, as shown in Figure 10, and as the manifold diameter increases, as shown in Figure 11. Methods to reduce losses are being considered.

Simply reducing the manifold diameter is not a good idea because it increases the pressure loss of the liquid and increases the power consumption of the pump. On the other hand, by providing an enlarged diameter section in the piping and making the manifold diameter smaller as the cell at the end increases depending on the liquid flow rate, it is possible to reduce the shunt current without increasing the pump power. A battery has also been devised (Japanese Unexamined Patent Publication No. 60-37652). However, this method
Assembly accuracy is strict, and manufacturing costs only increase (
, maintenance is inconvenient due to cell incompatibility.

Furthermore, Japanese Patent Application Laid-Open No. 59-127378 proposes a method for preventing leakage current by blowing air bubbles into the manifold, but in order to prevent air bubbles from entering the cells, the cell structure becomes complicated, and This is difficult to realize because there is a high possibility that the distribution of liquid to each cell will be non-uniform due to variations in the behavior of the bubbles.

From the above points, practical measures include increasing the cell electrode area and increasing the net current (by doing so, relatively reducing the proportion of shunt current loss in the manifold section, and Without increasing the number of cell layers,
A method is adopted in which the shunt current loss is kept within a predetermined value or less.

Batteries for power storage equipment installed in distribution substations include:
The total energy efficiency must be 70% or more (
Moonlight project development target performance), to achieve this, it is necessary to achieve efficiency of 80% or more at the DC end, excluding auxiliary equipment such as inverters and pumps, and to increase the electrode area (6000cm).
+j) If 50 cells are laminated, the shunt current loss will be over 10%, and considering energy loss due to internal battery resistance, it will be difficult to achieve the above efficiency of 80%. There is also a report that the maximum number of cells is about 20 to 30 cells (1988 "Research results for the development of new battery power storage systems; New Energy Development Organization)".

However, the final required DC voltage is several hundred to 1,000 volts or more due to the specifications of the orthogonal converter, so in the above-mentioned stack, it is necessary to connect several dozen or more stacks in series using bus bars. In equipment for power distribution substations, battery units of several MW are required, but the number of stacks required ranges from several hundred to more than one foundation per unit.

In this way, a stack with a small number of laminated layers requires a huge number of stacks, and therefore, parts other than the cell body among the materials composing the stack, such as end plates, leads, stack fasteners MN, and bus bars, etc. Expenses increase.

Furthermore, since each stack requires access for maintenance and inspection, the installation area becomes enormous.

The present invention has been made in pursuit of the above points, and aims to provide a more compact, high-performance, low-cost battery equipment by increasing the number of stacked cells without increasing shunt current loss. That is.

[Means and effects for solving the problem] No. 1 of the present application
The redox battery of the invention consists of a large number of cells stacked by a bipolar connection method, in which the large number of cells is divided into a plurality of stacked units, and a liquid partition consisting of a conductor and a frame is provided between each stacked unit. It is characterized in that a plate is inserted to partition the stack, and a liquid supply pipe and a liquid discharge pipe are connected to each stacked unit.

Further, the redox battery of the second invention of the present application is a redox battery consisting of a large number of cells stacked by a bipolar connection method, in which the large number of cells is divided into a plurality of stacked units, and a conductor and a frame are placed between each stacked unit. A book characterized in that a liquid partition plate consisting of a body is inserted to partition the layer, a liquid supply pipe and a liquid discharge pipe are connected to each laminated unit, and an electrical insulating device is attached to the liquid supply pipe and/or the liquid discharge pipe. In the redox battery of the invention, it is preferable that the laminated units have an integrally portable structure, and it is also preferable that the electrical insulating device has the function of a flow meter.

In addition, an insulating device may be attached to each substack as shown in Figures 1 and 2, but it is not possible to connect equipotential substacks with the same header as shown in Figure 5. , insulation can also be achieved by installing an insulating device between each header and the main pipe. Although only the positive electrode liquid supply is shown in FIG. 5, the positive electrode liquid discharge, negative electrode liquid supply, and drainage may be similarly connected.

In the redox battery of the present invention, a liquid partition plate consisting of a conductive plate, a frame, etc. is inserted every 10 to 100 cells, preferably every 20 to 50 cells, and each partitioned laminated unit (hereinafter referred to as a substack) is Supply and drain fluid. Additionally, electrical isolation devices may be installed on the piping connected to each substack. In this case, since each substack is electrically insulated, no matter how much the number of cells in the stack is increased, the shunt current loss remains at an amount corresponding to the number of substack layers. Therefore, it is possible to dramatically increase the number of stacked cells while maintaining efficiency, and it is possible to significantly reduce the installation area and cost.

Conventionally, increasing the number of laminated layers made it difficult to distribute liquid evenly to each cell, and it was not possible to adjust this from the outside. Since the flow rate can be monitored and adjusted for each substack, substantially equal distribution of liquid can be achieved.

As the above-mentioned flowmeter, for example, a known rotary flowmeter as shown in FIG. 6 (ta+, mountain), (C1, fdl) can be used.

Furthermore, if the substack is made integrally portable, it is easy to assemble the device, and the voltage of each substack is
It is also preferable in terms of maintenance and management because it is possible to monitor the liquid flow rate and replace the entire substack if there is an abnormality.

(Example) Preferred examples and comparative examples of the present invention will be described in detail below with reference to the drawings. However, the shapes of the components described in this example, their relative positions, etc. Unless otherwise stated, the scope of the present invention is not intended to be limited thereto, and these are merely illustrative examples.

Example 1 FIGS. 1 to 3 show an example of the structure of a redox battery of the present invention. In the figure, the substack 16 includes a liquid partition plate 17, a bipolar plate 18, a positive electrode chamber 20, a diaphragm 21, a negative electrode chamber 22, and a liquid supply/discharge section 23. The positive electrode liquid and the negative electrode liquid are supplied to and discharged from the substack 16 from the positive electrode liquid supply header 24 and the negative electrode liquid supply header 25 via a liquid supply pipe 29 having a flow M control valve 26, a flow meter 27, an insulating device 28, etc. The positive electrolyte population 30 and the negative electrolyte population 31 of the section 23 are introduced.

In the substack 16, the positive electrode liquid and the negative electrode liquid are supplied from the positive electrode liquid inlet manifold 32 and the negative electrode liquid inlet manifold 33 to the positive electrode chamber 20 and the negative electrode chamber 22 in the section partitioned by the liquid partition plate 17, and then to the positive electrode liquid outlet manifold. 34 and the liquid supply/discharge part 23 via the negative electrode liquid outlet manifold 35
It is collected at the positive electrode liquid outlet 36 and the negative electrode liquid outlet 37 , and is discharged through the positive electrode liquid discharge header 39 and the negative electrode liquid discharge header 40 through the liquid discharge pipe 38 .

Note that the insulating device 28 and the fL quantity meter 27 can be of a dual-purpose type as described later. Further, the liquid partition plate 17 and the bipolar plate 18 may have an integral structure in which electrodes are bonded to both surfaces thereof.

In this way, in the battery of the present invention, since each substack 16 is insulated, high voltage can be achieved with high lamination, compared to conventional batteries where one stack has as many layers as the substack of the present invention. As a result, the space required for access and accessory equipment such as a stack holding device can be significantly reduced. 41 is a hydraulic stack tightening device.

Example 2 and Comparative Example 1 Figures 6(a), fb), (C1, and d+) show examples of electrical insulating devices. In addition to increasing the size, the increase in pressure loss is suppressed by adopting a rotating mechanism.In addition, the same effect can be expected with plunger one-type and rotary one-type types.These can control the flow rate by monitoring the rotation speed, etc. It can also function as a meter.

Table 1 shows a comparison of shunt current loss when these insulating devices were attached (Example 2) and when no insulating device was attached (Comparative Example 1). In the examples, for the oval gear type (Fig. 4 (a)) and the roots type (Fig. 4 mountain),
There is little current loss by itself, and most of the current loss is in the manifold section within the substack. The turbine meter method (Fig. 4 (C)) and the tube flow monitor method (Fig. 4 (d)) have somewhat inferior insulation performance, but performance can be improved by improving manufacturing accuracy and reducing the clearance. Expected to be usable. In both cases, 360
This is the value for the case of 〇−×30 cell substack×4 series.

Table 1 On the other hand, in Comparative Example 1, the piping channels connecting the substacks have almost no insulation function, so the current loss through this channel is large, and the features of the substack system according to the present invention cannot be fully utilized. He will not survive.

Embodiment 3 FIG. 4 shows an example of an integrally portable structure. Each cell has several positioning holes 44, and by stacking them along several positioning and supporting rods 45 vertically attached to the liquid supply/discharge section 23, positioning can be easily performed with high precision. .

The thus stacked cells are fixed to the liquid supply/discharge section 23 with one touch by several sets of hinges 46 and spring hooks 42 attached to the final end cell or end block, and are integrated as a substack 16. Ru. Since the seal between each cell is performed by the hydraulic stack tightening device 41 shown in Fig. 1, the fixing force of the spring type hook 42 is sufficient to prevent the substack 16 from coming apart during assembly into the stack or during transportation. is sufficient. Note that instead of the spring type hook, spring wire, play turn buckle, etc. can also be used. 43 is an eye bolt.

Example 4 and Comparative Example 2 Table 2 shows a comparison of the battery configurations and the required floor space of the battery room between the method of the present invention (Example 4) and the conventional method (Comparative Example 2) for equipment of the same scale.

Table 2 The dimensions of each cell are the same for both types, but in the conventional method, it is difficult to use a hydraulic tightening device in terms of cost and space, so it is difficult to tighten flanges and bolt nuts. This assumes that the method is adopted.

As is clear from Table 2, in the method of the present invention, it is possible to increase the number of stacked cells by more than 10 times compared to the conventional method, and the number of stacks constituting a unit can be reduced by 1/1.
It can be consolidated to 10 or less, and the installation area can be reduced to 1/4 or less.

Example 5 and Comparative Example 3 Table 3 shows the method of the present invention (Example 5) and the conventional method (Comparative Example 3) for stacks in which the same number of cells of the same size are laminated.
) shows the efficiency. According to Table 3, the method of the present invention:
It can be seen that even if the number of laminated layers is increased compared to the conventional method, the shunt current loss does not increase, so high efficiency can be maintained.

The reason why the pump power loss is higher in the conventional method than in the method of the present invention is that the liquid supply in the method of the present invention is distributed to four locations, whereas in the conventional method, the loss of power is higher in the conventional method than in the method of the present invention. As shown, the pressure loss at the manifold increases because it is concentrated in one location.

Table 3 Example 6 and Comparative Example 4 The flow distribution of each cell in the stack of 120 cells shown in FIG. Show how they are different. Note that FIG. 8(a) shows a conventional battery, and FIG. 8(bl) shows a battery of the present invention.

The flow rate distribution tends to decrease as cells move away from the liquid introduction part, but according to the method of the present invention, the substack (
Since the flow rate can be adjusted externally for every 30 cells, the fluctuation range is small.

On the other hand, in the conventional method, the imbalance in flow rate distribution is large, and the flow rate at the extreme end is about 50% of the average flow rate. As charging and discharging progress, the active material concentration in the electrolyte gradually decreases, but if it decreases to an extreme level, for example, during charging, hydrogen gas generation side reactions occur in the negative electrode liquid, resulting in a decrease in efficiency.
Stable operation becomes difficult. For this reason, measures have been taken to set a lower limit on the active material concentration and to terminate charging or discharging at that point. However, as in Comparative Example 4, when there is a cell in the stack 49 with an extremely low flow rate, the reaction amount (or current) is the same for each cell, so only the cell with a low flow rate
The concentration of the active material decreases quickly, and if you continue charging and discharging any longer, side reactions will occur as mentioned above, so charging and discharging must be stopped at that point, and therefore the active material cannot be used. rate decreases, and the apparent storage capacity fi (KW
I() will decrease.

〔Effect of the invention〕

As explained above, the present invention achieves high efficiency and high output by inserting a liquid partition plate every several tens of cells in a battery stack and configuring the liquid to be supplied and drained for each partitioned stacked unit. It is possible to provide a redox battery of 100%, and the merits of scale due to the increased size have the effect of reducing costs and reducing the installation area. Further, in the case of a configuration in which an electrical insulating device is attached to the supply/drainage piping, the above-mentioned effects are further exhibited.

[Brief explanation of the drawing]

FIG. 1 is an explanatory front view showing an example of the stack configuration of the redox battery of the present invention, FIG. 2 is an explanatory cross-sectional view taken along the line A-A in FIG. Part 4 is an explanatory diagram showing an example of an integrally portable battery of the present invention, Figure 5 is an explanatory diagram showing an example of a location for installing an insulating device, and Figure 6 is an explanatory diagram showing an example of a location for installing an insulating device. Fig. 7 is a diagram showing the flow rate distribution of each cell in the battery of the present invention in Example 6 and the conventional battery in Comparative Example 4, and Fig. 8 is a diagram showing the conventional battery in Comparative Example 4. , and an explanatory diagram showing the battery of the present invention in Example 6, FIG. 9 is an explanatory diagram of a power storage system using a redox battery, and FIG. 1O is a diagram showing the relationship between the number of stacked cells and shunt current loss. Figure il1 is a diagram showing the relationship between manifold diameter and shunt current loss. 1...-power plant, 2...-substation equipment, 3--load, 4
-Inverter, 5... Redox battery, 6.7-...
Tank, 8 - flow type electrolytic cell, 9 - diaphragm, 1 Qa - positive electrode liquid chamber, 10 kl - one negative electrode liquid chamber, 11 - positive electrode, 12 -...
-Negative electrode, 13a, I S b-pump, 14.15-circulation path, 16-...substack (layer unit), 17...
-Liquid partition plate, 18--Bipolar plate, 20-Positive electrode chamber,
21-diaphragm, 22--negative electrode chamber, 23-liquid supply/discharge section,
24--Positive electrode liquid supply hesodar, 25--Negative electrode liquid supply heso-ge 126-Flow N control valve, 27--Flow meter, 28-.
・Insulator, 29--Liquid supply pipe, 30--Positive electrode liquid inlet, 31--Negative electrode liquid inlet, 32--Positive electrode liquid inlet manifold, 33--Negative electrode liquid inlet manifold, 34--Positive electrode liquid outlet Manifold, 35...-Negative electrode liquid outlet manifold, 3
6--Positive electrode liquid outlet, page 37-Winding liquid outlet, 38--Liquid discharge pipe, 39-Positive electrode liquid discharge hesoge 14--Negative electrode liquid discharge hooder, 41--Hydraulic stack tightening device, 42・
- Buff type hook, 43- Eye bolt, 44- Positioning hole, 45- Positioning and support rod, 46- Hinge,
47... Positive electrode liquid supply main tube, 48-bus bar, 49...
- Stack applicant Kawasaki Heavy Industries Co., Ltd.

Claims (1)

[Claims] 1. In a redox battery consisting of a large number of cells stacked by a bipolar connection method, the large number of cells are divided into a plurality of stacked units, and a liquid partition consisting of a conductor and a frame is provided between each stacked unit. A redox battery characterized by inserting a plate into the partition and connecting a liquid supply pipe and a liquid discharge pipe to each laminated unit. 2 Claim 1 in which the laminated unit has an integrally transportable structure
Redox battery as described in section. 3. In a redox battery consisting of a large number of cells stacked using a bipolar connection method, the large number of cells is divided into multiple stacked units, and a liquid partition plate consisting of a conductor and a frame is inserted between each stacked unit to partition the cells. A redox battery, characterized in that a liquid supply pipe and a liquid discharge pipe are connected to each stacked unit, and an electrical insulating device is attached to the liquid supply pipe and/or the liquid discharge pipe. 4. The redox battery according to claim 3, wherein the electrical insulating device also has the function of a flowmeter.