JPH0582033B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a battery having a flow-through type electrolytic cell, that is, a battery system that stores and/or transforms electric power using a flow-through type battery.

[Prior art]

Electricity is easy to convert into various forms of energy, easy to control, and does not pollute the environment when consumed, so its share in energy consumption is increasing every year. Until now, most of this electricity has been generated through hydroelectric power, thermal power generation, and nuclear power generation. However, in the future, it is thought that the proportion of power generation by solar power generation, wind power generation, etc. will increase in response to the increase in power consumption, resource conservation, and environmental pollution issues during power generation. Furthermore, in order to use electricity in remote or remote areas, where up until now it was necessary to install power transmission lines over long distances or to generate electricity in-house using a diesel engine or other device that transports fuel, it is now possible to use independent power generation facilities. It is thought that solar power generation, wind power generation, etc. will be replaced.

On the other hand, a unique feature of power supply is that it must be supplied in a manner that responds promptly to power consumption. Therefore, solar power generation, wind power generation, etc.
Since the amount of power generated is affected by factors such as wind,
At least on the ground, it cannot be a sufficient power supply source on its own, but in combination with some kind of power storage equipment,
For the first time, it becomes a stable power supply source.

Various types of power storage equipment can be considered to be combined with the above-mentioned solar power generation, wind power generation, etc., but among them, a particularly effective one is a battery having an electrolyte flow type electrolytic cell, that is, a flow type battery. In other words, with commercially available batteries, a reaction occurs depending on the current even when the current is weaker than the rated value, it is possible to respond to a voltage smaller than the rated value by switching the number of cells, and it is possible to generate electricity just by using the amount of electrolyte. It has great compatibility, such as being able to determine the storage amount and having a transformer function that makes the input voltage and output voltage different, so it is suitable for power storage in combination with power generation equipment that has large fluctuations in generated power, such as solar power generation and wind power generation. As a facility, it can be said to be excellent.

Here, as an example of a flow-through battery, an overview of the principle of a redox flow battery is shown in Figure 1.
This will be explained using FIG.

FIG. 1 shows a charging state of a power charging/discharging system using a redox flow battery, and FIG. 2 similarly shows a discharging state.

In these figures, 1 is a charging power source, 2 is a load, 3 is an inverter, and 4 is a redox battery, which is composed of tanks 5a, 5b, 6a, 6b, pumps 7, 8, and a flow-through type electrolytic cell 9. Flow type electrolytic cell 9
is equipped with a positive electrode 10, a negative electrode 11, and a diaphragm 12 separating the two electrodes, and a positive electrode liquid 13 and a negative electrode liquid 14 are housed in left and right chambers partitioned by the diaphragm 12.
An example is shown in which the positive electrode liquid 13 is a hydrochloric acid solution containing Fe ions, and the negative electrode liquid 14 is a hydrochloric acid solution containing Cr ions.

Next, the effect will be explained.

The power transmitted from charging power source 1 is redox
The voltage is transformed to an appropriate voltage by the flow battery 4, AC/DC conversion is performed by the inverter 3, and the voltage is supplied to the load 2. On the other hand, when surplus power is generated, the redox flow battery 4 is charged. In this case, the first
from tank 5b to tank 5a as shown in the figure.
Positive and negative electrode liquids 1 are pumped from a to 6b with pumps 7 and 8.
Charging is performed while gradually feeding 3 and 14. When Fe ions are used in the positive electrode solution 13 and Cr ions are used in the negative electrode solution 14, the reactions that occur in the flow-through electrolytic cell 9 are reactions on the charging side in the following equations (1) to (3).

Positive electrode side: Fe ³⁺ +e discharge――→ ←―― Charge Fe ²⁺ …(1) Negative electrode side: Cr ²⁺ discharge――→ ←―― Charge Cr ³⁺ +e …(2) Total reaction: Fe ³⁺ +Cr ²⁺ discharge――→ ←―― Charge Fe ²⁺ +Cr ³⁺ …(3) In this way, power is transferred to the positive electrode liquid 13 and the negative electrode plate 1.
It is accumulated in 4.

On the other hand, if the supplied power is less than the demanded power, the reactions on the discharge side in equations (1) to (3) above are performed,
Orthogonal transformation is performed by the inverter 3 and power is supplied to the load 2.

[Problem that the invention seeks to solve]

Incidentally, the flow-through type battery including the above-described redox flow battery requires movable parts such as a pump for circulating the electrolyte and power for operating the movable parts. In a flow-through type battery, this pump power becomes a loss, reducing the overall efficiency of the battery. In addition, when multiple cells or stacks (collected batteries) are connected in series, shunt current (leakage current due to liquid junction) occurs, which becomes a loss and reduces the overall efficiency of the battery. .

When using a flow-through battery for power storage and/or voltage transformation for solar power generation, wind power generation, etc., the generated power (KW) fluctuates widely, and therefore the battery input power (KW) fluctuates widely. However, even if the input power decreases, unless the power and shunt current decrease in proportion to the input power, the efficiency of the battery with respect to the input power will decrease. The same applies when the load side power (KW), that is, the battery output (KW) fluctuates during discharging. Therefore, in response to fluctuations in input power and output power, the amount of electrolyte circulation can be varied by switching the number of pumps in operation, controlling speed, etc., reducing the pump power, and reducing the number of stacks (polymerized batteries) used. It is conceivable to reduce the value of shunt current by switching.

However, when charging and discharging with extremely small input power or output power compared to the rated charge/discharge power (KW) of the battery, there are problems with pump control, concerns about hydrogen generation in the battery, etc. It will be difficult to respond using methods alone. Furthermore, as mentioned above, in the method of switching the number of pumps in operation in response to fluctuations in charging and discharging power, there are restrictions on the frequency and interval of starting and stopping the pumps, and fluctuations in generated power and/or required load power It is not always possible to respond instantly, and the generated power and/or
There will be times when the required load power and the charging/discharging power of the circulation type battery do not match.

By the way, conventional solar power generation or wind power generation,
Examples of combinations with flow-through batteries (for example,
17thIECEC, 829103, DESIGN FLEXIBILITY
OF REDOX FLOW SYSTEMS), the weaknesses of the above-mentioned flow-through type batteries, namely the weak generated power and/or
Or, no particular countermeasures have been taken for the reduction in efficiency during charging and discharging with load power and the poor followability to fluctuations in generated power and/or load power.

The present invention solves these problems of conventional flow-through type batteries and provides an electrolyte flow-type battery system that can respond quickly and accurately to fluctuations in generated power or load power. It is intended for this purpose.

A second object of the present invention is to provide an electrolyte flow type battery system that can charge and discharge with high efficiency even weak generated power or load power.

[Means for solving problems]

The present invention provides an electrolyte flow type electrolytic cell and an electrolyte flow type battery having a movable part such as a pump when used for power storage and/or voltage transformation such as solar power generation and wind power generation. By combining batteries with lead-acid batteries, etc. that do not require moving parts such as pumps, charging circuits and discharging circuits for the lead-acid batteries are used to buffer short-term fluctuations in generated power such as solar power and short-term fluctuations in load power. The electrolyte flow type battery system is characterized in that the electrolyte flow type battery system is connected in parallel to the charging circuit and the discharging circuit of the electrolyte flow type battery, and as an important feature, an electrolyte flow type electrolytic cell and a pump are provided. A lead-acid battery that does not require the electrolyte flow type battery and moving parts such as a pump when used for power storage and/or voltage transformation for solar power generation, wind power generation, etc. In the case of low input and low output, where the efficiency including the pump power of the electrolyte flow type battery is significantly reduced, the pump can be charged and discharged only by the storage battery, etc., by using a timer to avoid starting and stopping the pump. An object of the present invention is to provide an electrolyte flow type battery system characterized by performing the following.

〔Example〕

A comparative explanation of a conventional system and an improved system according to the present invention will be given below with reference to the drawings.

3 and 4 are diagrams showing the concept of using a flow-through type battery as a power storage device for solar power generation or wind power generation, and FIG. 3 shows a system in which the present invention is not applied, and FIG. 4 shows each system to which the present invention is applied.

In Figures 3 and 4, 15 is a power generation device such as a solar power generation device or a wind power generation device, 16 is a flow-through type battery, 17 is an inverter (DC/AC converter), 18 is a load, and 19 is a movable device such as a pump. Each shows a battery such as a lead-acid battery that does not require parts.

FIG. 5 shows the relationship between time and power in the case of charging in an embodiment to which the present invention is applied, and FIG. 6 shows the relationship between time and power in the case of discharging in the embodiment to which the present invention is applied.
Shows the relationship between time and power. In Figure 5, the shaded area indicates the charging area with a lead-acid battery, etc.
The other parts show the flow-through battery charging part. or,
In FIG. 6, the shaded area shows the discharge area in a lead-acid battery or the like, and the other areas show the discharge area in a flow-through type battery. In addition, in this example, two 500W redox flow batteries stack (collected batteries) are used as circulating type batteries, totaling 1KW, and as a power generation device,
Four 200W solar panels provide a total of 800W, and one 500W lead-acid battery is used.

First, FIG. 5 will be described in detail below. Detects that the solar power generation power, that is, the charging power of the entire battery (redox flow battery and lead-acid battery) has reached point A, and after holding it for △T time with the timer, confirms and starts the first set of stacks. Or stop it. Similarly, it is detected that the charging power has reached point B, and this is confirmed after ΔT time, and the second set of stacks is started or stopped. Then,
At time T ₁ , the generated power becomes A and the timer operates, but since it takes time to confirm △T, the generated power (shaded area) up to T ₁ ' is generated not by the redox flow battery but by the lead-acid battery. It will be charged.
Similarly, at T ₁₀ , the generated power becomes A, but △
After T time, at time T ₁₀ ', the first set of stacks is stopped, and the lead-acid battery is charged with electric power smaller than A after T ₁₀ '.

If the present invention is not applied and a lead-acid battery is not provided, A on the left side of T ₁ ' and on the right side of T ₁₀ ' in the figure
For smaller power, do not charge or
Alternatively, the first set of flow-through type batteries (rated at 500W) is charged with low efficiency (in this case, a timer for starting and stopping the first set is not provided).In other words, the present invention enables charging with weak charging power. On the other hand, it becomes possible to perform charging with high efficiency.

On the other hand, it is necessary to provide a timer to avoid frequent starting and stopping of the pump within a short period of time. If there is no timer, the second set of stacks will stop at T ₃ , T ₅ , and T ₇ , and T ₄ , T ₆ , and
The second set of stacks will start at T ₈ , but by providing a timer, △T
The second set of stops will not occur until confirmation is made at time T ₃ ′, T ₅ ′, and T ₇ ′, so in reality,
The second set will continue to operate,
This avoids starting and stopping due to short-term power fluctuations such as from T ₃ to T ₄ , from T ₅ to T ₆ , and from T ₇ to T ₈ . By providing this timer, the power reaches the value of B, the starting power of the second set, at time T ₂ , but the second set actually starts at time T ₂ ', which is △T time later. Become. Then, between T ₂ and T ₂ ', the generated power (shaded area) exceeding the first set's capacity of 500 W is charged by the lead-acid battery.

That is, by applying the present invention and providing a lead-acid battery, it is possible to charge the generated power that exceeds the capacity of the first set during the timer confirmation time ΔT.
The overall charging efficiency can be increased.

If the present invention is not applied and a lead-acid battery or the like is not provided, the generated power exceeding the capacity of the first set during the confirmation time ΔT by the timer will not be charged.

Next, FIG. 6 will be described in detail below. Detects that the load power, that is, the discharge power of the entire battery (redox flow battery and lead-acid battery) has reached point a, and after holding it for △t time with a timer, confirms and starts or stops the first set of stacks. I do. Similarly, it is detected that the discharge power has reached point b, and this is confirmed after Δt time, and the second set of stacks is started or stopped. Therefore, at time t ₁ , the load power exceeds a and the timer is activated, but since it takes time to confirm △t, the load power (shaded area) up to t ₁ ' is not due to the redox flow battery. , discharged by a lead-acid battery. Similarly, at time t ₈ , the load power becomes less than a, but after time △t
At time t ₈ ', the first set of stacks stops, and the lead-acid battery discharges a smaller amount of power than a after t ₈ '.

If the present invention is not applied and a lead-acid battery is not provided, the power smaller than a on the left side of t ₁ ' and on the right side of t ₈ ' in the figure will not be discharged, or the first set of A flow-through type battery (rated at 500W) results in low-efficiency discharge (in this case, there is no timer for starting and stopping the first set). That is, according to the present invention, it is possible to perform highly efficient discharge with weak discharge power.

On the other hand, in order to avoid frequent starting and stopping of the pump for a short period of time, during discharging as well as during charging,
It is necessary to provide a timer. If there was no timer, the second set of stacks would stop at t ₃ and t ₅ , and the second set of stacks would start at t ₄ and t ₆ , but by providing a timer, The second set of stops will not be performed until confirmation is made at t ₃ ′ and t ₅ ′ after △t time, so
In reality, the second set continues to operate continuously to avoid starting and stopping due to short-term power fluctuations from t ₃ to t ₄ and from t ₅ to t ₆ . By providing this timer, the power reaches the value b of the second set of starting power at time t ₂ , but in reality, △
The second set will be activated at time t ₂ ' after t hours. Then, between t ₂ and t ₂ ', the load power (shaded area) exceeding the capacity of the first set of 500 W is discharged by the storage battery.

That is, by applying the present invention and providing a lead-acid battery, it is possible to discharge even a load power exceeding the capacity of the first set during the confirmation time Δt by the timer, and stable discharge can be performed as a whole. becomes possible. If the present invention is not applied and a lead-acid battery or the like is not provided, the load power exceeding the capacity of the first set will not be discharged, that is, will not be supplied during the confirmation time Δt by the timer.

〔Effect of the invention〕

The present invention relates to an electrolyte flow type battery system that stores and/or transforms power generated by solar power generation, wind power generation, etc. using a flow type battery having an electrolyte flow type electrolyzer. By connecting a battery that does not require moving parts such as a pump so that its charging circuit and discharging circuit are parallel to the charging circuit and discharging circuit of the above-mentioned flow-through type battery, short-term power generation such as solar power can be achieved. The buffering of fluctuations and short-term fluctuations in load power can be carried out, and in addition, when the charging power or discharging power is lower than a predetermined low power, moving parts such as pumps such as lead-acid batteries are required. By charging or discharging only with a battery that does not have a battery, it can be used for charging and discharging weak generated power such as solar power and weak load power, and it has stable control and high efficiency charging and discharging. is obtained, and has an extremely large practical effect.

In addition, when using electrolyte flow type battery systems for power storage and voltage transformation, electrolyte flow is necessary for short-term input/output fluctuations, that is, fluctuations in charging power and/or discharging power, and for low input/output. This prevents efficiency from decreasing due to a relatively large proportion of loss due to moving parts such as pumps in a type battery, reduces auxiliary power loss, and enables stable economical operation.

[Brief explanation of the drawing]

Figure 1 shows the charging state of a power charging/discharging device using a redox flow battery, Figure 2 also shows the discharging state, and Figures 3 and 4 show the power generation by solar power or wind power. FIG. 3 is a diagram showing the concept when a flow-through type battery is used as a power storage device, and FIG. 3 shows a system in which the present invention is not applied, and
Figure 4 shows the system when the present invention is applied.
FIG. 5 is a graph showing the relationship between time and power in the case of charging in an embodiment to which the present invention is applied, and FIG. 6 is a graph showing the relationship between time and power in the case of discharging in the embodiment to which the present invention is applied. It is a graph showing the relationship between. 1... Charging power supply, 2... Load, 3... Inverter, 4... Redox flow battery, 5a, 5
b, 6a, 6b... Tank, 7, 8... Pump,
9...Flow type electrolytic cell, 10...Positive electrode, 11...Negative electrode, 12...Diaphragm, 13...Positive electrode liquid, 14...Negative electrode liquid, 15...Power generator, 16...Flow type battery,
17...Inverter, 18...Load, 19...Lead acid battery.

Claims (1)

[Scope of Claims] 1. When using an electrolyte flow type battery having an electrolyte flow type electrolytic cell and a moving part such as a pump for power storage and/or voltage transformation such as solar power generation or wind power generation,
By combining the electrolyte flow type battery with a lead-acid battery that does not require moving parts such as a pump, the lead-acid battery can be charged in order to buffer short-term fluctuations in generated power such as solar power and short-term fluctuations in load power. An electrolyte flow type battery system, characterized in that a circuit and a discharge circuit are respectively connected in parallel to a charging circuit and a discharge circuit of the electrolyte flow type battery. 2. When using an electrolyte flow type electrolytic cell and an electrolyte flow type battery having a moving part such as a pump for power storage and/or voltage transformation for solar power generation, wind power generation, etc.,
By combining the electrolyte flow type battery with a lead-acid battery etc. that does not require moving parts such as a pump, in the case of low input and low output where the efficiency including the pump power is significantly reduced in the electrolyte flow type battery, the above-mentioned method can be used. An electrolyte flow type battery system characterized in that charging and discharging is performed only by the storage battery, etc., while avoiding starting and stopping of the pump using a timer.