JP3351442B2 - Storage type temperature difference battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel redox temperature difference battery having a normal power generation function and a power storage function when there is a temperature difference, and enabling discharge when the temperature difference disappears. In particular, the present invention relates to a temperature difference battery that is effective as a backup power supply for waste heat utilization and cogeneration.

[0002]

2. Description of the Related Art Conventionally, as a thermoelectric converter for converting heat energy into electric energy, an electrochemical temperature difference battery has been known. FIG. 3 shows the structure of this conventional temperature difference battery. It is. That is, in a conventional electrochemical temperature difference battery, an electrode made of the same material is contained in a solution 2 containing a redox counter ion that performs a reversible charge transfer reaction on the electrode, and a low-temperature medium 4 and a high-temperature medium 5 are provided between the two electrodes. A temperature difference is given, and the electrode is provided as a low-temperature electrode 1 and a high-temperature electrode 3, and a potential difference, that is, a thermoelectromotive force is generated between the two electrodes. For example, when potassium ferrocyanide and potassium ferricyanide are used as the redox pair compound and water is used as the solvent, a negative thermoelectromotive force is generated, and the following reaction occurs in the low-temperature electrode 1 and the high-temperature electrode 3. The high-temperature electrode side becomes the negative electrode and the low-temperature electrode side becomes the positive electrode.

[0003] ^{_{Fe (CN) 6 3- + e}} - → Fe (CN)
₆ ^4- (cold electrode side, a positive ^{_{electrode) Fe (CN) 6 4- →}} Fe (CN) 6 3- + e - ( hot electrode side, the negative electrode) wherein the ^4- Fe (CN) ₆ at a low temperature of the positive electrode In the case of a high-temperature negative electrode, Fe (CN) ₆ ^3- is generated, and each product circulates internally by diffusion, convection, etc., and moves to the counter electrode, whereby a steady reaction occurs and a current flows. In the temperature difference battery system having such a configuration, when the operation is stopped and the temperature difference between the positive and negative electrodes disappears, the thermoelectromotive force also disappears, and it is impossible to extract power. In addition, since water is used as a solvent as in the above system, there is a disadvantage that the high-temperature electrode side temperature cannot be increased to 100 ° C. or higher.

[0004]

SUMMARY OF THE INVENTION In order to solve the problem that the conventional redox temperature difference battery does not have a power storage function and is difficult to use at a high temperature, the present invention provides a high-temperature side electrode and a low-temperature electrode. Each redox pair generated at the side electrode is arranged in a molten state, and further, the redox pair is accumulated by disposing an ion-conductive solid electrolyte,
By holding the concentration difference and forming a concentration difference battery, in addition to a normal power generation function when there is a temperature difference, by providing a power storage function, a storage type temperature difference battery having a discharge function when the temperature difference disappears is provided. To provide.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a method for forming a halo between a high-temperature electrode and a low-temperature electrode arranged at different temperatures, the oxidation-reduction potential of which varies with temperature.
A redox pair compound having a gen ion as an anion is disposed in a molten state and further does not pass through the redox pair.
A temperature difference battery in which a halogen ion conductive solid electrolyte is disposed, wherein two discharge electrodes are disposed between the halogen ion conductive solid electrolyte and the high temperature electrode, and between the halogen ion conductive solid electrolyte and the low temperature electrode. It is a storage type temperature difference battery characterized by the following. More specifically, in the energy storage type temperature difference battery of the present invention, the redox pair compound whose oxidation-reduction potential changes with temperature is melted between the high-temperature side electrode and the low-temperature side electrode set at a temperature equal to or higher than the melting point. By utilizing the fact that a thermoelectromotive force is generated when arranged, the respective redox pairs generated by the high-temperature side electrode and the low-temperature side electrode are accumulated, the concentration difference is enlarged, and a concentration difference battery is formed. The two discharge electrodes disposed between the conductive solid electrolyte and the high and low temperature electrodes are characterized by exhibiting a normal power generation function when there is a temperature difference, a power storage function, and a discharge function when the temperature difference disappears. Further, the present battery system is characterized in that it can be used at a high temperature because a solvent such as water is not used.

[0006]

The power storage type temperature difference battery of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows the configuration of a storage battery of the present invention. The low-temperature electrode 1 is heated by a low-temperature medium 4 and a high-temperature medium 5 with a temperature difference higher than the melting point of redox compound. Between the redox and the compound 12 in which the oxidation-reduction potential changes between temperature and the high-temperature electrode 3 depending on the temperature
In addition, an ion conductive solid electrolyte 6 that does not pass through the redox pair is disposed, and a low temperature region side discharge electrode 7 and a low temperature region side discharge electrode 8 are disposed between the ion conductive solid electrolyte 6 and the high and low temperature electrodes.

First, the ion conductive solid electrolyte 6 and the high and low temperature
Redox in low temperature area 9 and high temperature area 10 between electrodes
Redox versus Compound 12 in molten state with equal concentration of pairs
When inserted, it is proportional to the temperature difference between high-temperature electrode 3 and low-temperature electrode 1.
An electromotive force is generated. Here, the low-temperature side discharge electrode 7
And the high-temperature region side discharge electrode 8 is opened, and the high-temperature electrode 3
When the low-temperature electrode 1 is connected, the reaction described below is performed.
Current flows. That is, if the thermoelectromotive force is positive,
Compound with the general formula ML_Z, ML_{Z + n}When expressed as
In this form, the redox pair compound has a Z valence and a (Z + n) valence
Positive redox ion pair (M^{Z +}, M^{Z + n}) And monovalent shade
Ion (L^-) To separate the electrodes 3 and 1
Above, M^{Z +} → M^{(Z + n) +} + Ne^- Low temperature electrode ・ ・ ・ (1) M^{(Z + n) +} + Ne^- → M^{Z +} High-temperature electrode: The reaction shown in (2) proceeds and current flows. here
In the storage type temperature difference battery system of the present invention, the redox pair
Without, L^-Ion-conductive solid electrolysis that transmits only ions
Quality on the cold side electrode^{Z +}Consumption of
With M^{(Z + n) +}Accumulates and M on the hot side electrode
^{(Z + n) +}M with consumption of^{Z +}Accumulates and M at both electrodes
^{Z +}, M^{(Z + n) +}The density difference of each increases. like this
Ionic conductive solid electrolyte that does not permeate the redox couple
By providing the low-temperature side electrode, M ^{(Z + n) +}, High temperature side power
M at the pole^{Z +}Increases, and this concentration difference is maintained.
It becomes possible.

The concentration difference between these two polar regions is increased until the electromotive force between the high and low temperature electrodes due to the temperature difference becomes 0 V, and the charging reaction is completed here.

Next, a conventional power generation method when there is a temperature difference between the high and low temperature electrodes, as shown in FIG. Load 11 between the side discharge electrode 7 and the high temperature range side discharge electrode 8.
Should be connected. Here, the ion conductive solid electrolyte 6
The distance between the two discharge electrodes sandwiching is preferably as short as possible. If the two discharge electrodes are electrically insulated, they may be in contact with the ion-conductive solid electrolyte. By reducing the distance between the discharge electrodes in this way, it is possible to make the temperature difference between the discharge electrodes extremely small. Therefore, an electromotive force is generated between the discharge electrodes due to the concentration difference of the redox pair between the low-temperature side discharge electrode 7 and the high-temperature side discharge electrode 8 created by the connection between the high and low temperature electrodes. It becomes possible. The reaction of the redox couple in the normal power generation state is shown in FIG.
In the low temperature zone side discharge electrodes ^{7, M (Z + n)} + + ne - reaction → M Z ⁺ ··· (3) is, in the high temperature region side discharge electrodes ^{8, M Z + → M (} Z + n) + + ne ^- reaction of (4) is reacted in a direction density difference in each region disappears proceeds, power generation is performed.

On the other hand, in the low-temperature electrode 1 and the high-temperature electrode 3, the reactions of the equations (1) and (2) proceed in a direction to maintain the formed concentration difference. Here, the concentration difference between the low-temperature region 9 and the high-temperature region 10 in the normal power generation state is determined by the reaction of the equations (3) and (4) between the discharge electrodes to which the load 11 is connected. Is maintained. in this way,
As long as the temperature difference between the high-temperature electrode 3 and the low-temperature electrode 1 is maintained by the high-temperature medium 5 and the low-temperature medium 4, the reactions represented by the equations (1) to (4) progress steadily, and steady power generation becomes possible. In addition, by maintaining this concentration difference, it becomes possible to develop a power storage function.

Next, when the temperature difference between the high and low temperature electrodes has disappeared, the connection between the high and low temperature electrodes may be immediately disconnected and the connection may be made to be in an open state, whereby the reverse reaction of the equations (1) and (2) is performed. Can be stopped, and the reactions of the equations (3) and (4) can be discharged until the redox-to-concentration in the low temperature region 9 and the high temperature region 10 become equal.

As described above, the power storage type temperature difference battery of the present invention has a normal power generation function and a power storage function when there is a temperature difference, and a discharge function when the temperature difference disappears.

The redox pair used in the storage type temperature difference battery of the present invention can generate and use a conventional redox temperature difference battery that generates a positive or negative thermoelectromotive force. Those having a large value are preferred. For example, Fe ²⁺ / Fe ³⁺ , Cu ⁺ / Cu ²⁺ , Te ²⁺ / T
Redox pairs such as e ⁴⁺ , Hg ⁺ / Hg ²⁺ , Sn ²⁺ / Sn ⁴⁺ are preferably used. Further, as an anion for constituting a compound using these redox counter ions, C.I.
l ^-, Br ^- halogen ion and the like are suitably used. The battery system of the present invention is not limited to only these,
Any redox couple that can generate a thermoelectromotive force and form a molten salt upon heating can be used.

In the present invention, in order to obtain a molten salt of the redox compound at a desired temperature, an additive such as aluminum chloride generally used in molten salt electrolysis may be added.

The ion-conductive solid electrolytes for accumulating redox pairs include PbCl ₂ -based solid electrolytes, SrCl ₂ -based solid electrolytes, and BaCl ₂ -based solid electrolytes that do not allow redox counter ions to pass through and have halogen ion conductivity. An electrolyte, a PbBr ₂ -based solid electrolyte, an SrBr ₂ -based solid electrolyte, or the like may be used.

The discharge electrode used in the present invention preferably has a structure that does not hinder the passage of ionic species other than the redox counter ion that passes through the ion-conductive solid electrolyte 6, and is a porous metal having a low electric resistance. , Porous carbon, a metal sheet having a net structure, or the like can be used. Further, a metal may be bonded to both surfaces of the ion-conductive solid electrolyte by vapor deposition or the like, and this may be used as a discharge electrode. However,
The discharge electrode used in the present invention is not limited to the above-mentioned materials, and may be a material having low electric resistance and not obstructing passage of ionic species other than a redox pair.

The material for the high and low temperature electrode used in the present invention is not particularly limited, and any material having a current collecting function, such as a metal material or a carbon material having good conductivity can be used.

[0019]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

Example 1 As shown in FIG.
As quality 6, BaCl having a thickness of 0.1 mm_TwoBased solid electrolyte
And a low-temperature side discharge of 80 mesh platinum steel on both sides
The electrode 7 and the high-temperature-side discharge electrode 8 are connected to a redox-compound
CuCl and CuCl as 12_TwoArrange equimolar compounds of
And a 0.1 mm thick platinum plate on the outside
It was arranged as pole 1 and hot electrode 3. Where the low-temperature side
Discharge electrode 7, high temperature side discharge electrode 8, low temperature electrode 1, and high temperature
The cross-sectional area of the electrode 3 is 2.25 cm ^Two(1.5 × 1.5c
m), the ion-conductive solid electrolyte 6 and the low-temperature side discharge
Electrode 7 and ion-conductive solid electrolyte 6 and high-temperature side discharge electrode
8 between the low-temperature region side discharge electrode 7 and the low-temperature electrode 1
The distance between the high-temperature region side discharge electrode 8 and the high-temperature electrode 3 is 1 mm.
Is 1 mm, redox vs. compound is 0.2
25cm^Three(1.5 × 1.5 × 0.1 cm).

Next, the low-temperature medium 4 is set so that the temperatures of the low-temperature electrode 1 and the high-temperature electrode 3 become 500 ° C. and 800 ° C., respectively.
The temperature was controlled with the high-temperature medium 5 (in this embodiment, hot air was used). At this time, the copper ion redox pair showed a positive electromotive force, the low-temperature electrode 1 side became a negative electrode, and the high-temperature electrode 3 side became a positive electrode, and an electromotive force of 150 mV was generated. First, initial charging is performed using this electromotive force. The low temperature range side discharge electrode 7 and the high-temperature region side discharge electrodes 8 and an open state, connecting the low-temperature electrode 1 and the hot electrode 3 a current rapidly flows, the low temperature zone 9 Cu ²⁺
Was accumulated, Cu ⁺ was accumulated in the high-temperature region 10, and the concentration difference between the two regions was increased. After a few minutes, the electromotive force of the low-temperature electrode 1 and the high-temperature electrode 3 became 0V. On the other hand, the open electromotive force of the low-temperature side discharge electrode 7 and the high-temperature area side discharge electrode 8 in this initial charging process increases rapidly with the charging time, and when the electromotive force of the low-temperature electrode 1 and the high-temperature electrode 3 becomes 0V. To 138 mV. Next, constant-current discharge was performed with the low-temperature electrode 1 and the high-temperature electrode 3 connected to obtain a steady power generation state.
The voltage between the discharge electrode 8 and the high-temperature region side discharge electrode 8 showed a constant voltage value of 115 mV, and then a constant current discharge of 20 mA showed a constant voltage value of 92 mV.
Further, the low-temperature electrode 1 and the high-temperature electrode 3 are set at 500 ° C. so that the temperature difference between the two electrodes disappears,
When the high-temperature electrode 3 is opened and the discharge of 20 mA is continued between the low-temperature-area discharge electrode 7 and the high-temperature-area discharge electrode 8, the discharge of 2.5 h is continued and the capacity of 50 mAh is maintained even after the temperature difference disappears. It became clear that it had.

From the above results, it was found that the storage type temperature difference battery of the present invention was a battery having a normal power generation function when there was a temperature difference, a power storage function, and a discharge function after the temperature difference disappeared.

[0023]

The battery of the present invention is filled with a redox couple in a molten state between a high-temperature electrode and a low-temperature electrode, and provided with an ion-conductive solid electrolyte and two discharge electrodes. It has a steady-state power generation function, a power storage function, and a discharge function when the temperature difference disappears, and is extremely useful as a backup power supply for exhaust heat utilization and cogeneration.

Further, in the present invention, a much larger temperature difference can be obtained as compared with a conventional aqueous solution type temperature difference battery, and thus a large electromotive force can be obtained.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a configuration example of a storage type temperature difference battery according to the present invention.

FIG. 2 is a conceptual diagram showing a normal power generation principle of a power storage type temperature difference battery according to the present invention.

FIG. 3 is a conceptual diagram showing a configuration example of a conventional temperature difference battery.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Low temperature electrode 2 Redox pair containing solution 3 High temperature electrode 4 Low temperature medium 5 High temperature medium 6 Ion conductive solid electrolyte 7 Low temperature region side discharge electrode 8 High temperature region side discharge electrode 9 Low temperature region 10 High temperature region 11 Load 12 Melting redox pair compound

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01M 14/00

Claims (1)

(57) [Claims] Between 1. A different temperatures arranged the hot electrode and the cold electrode, Ha redox potential varies with temperature
A temperature difference battery in which a redox pair compound having a logen ion as an anion is disposed in a molten state, and a halogen ion conductive solid electrolyte that does not pass through the redox pair is disposed, wherein the halogen ion conductive solid electrolyte and a high-temperature electrode are disposed. And an energy storage type temperature difference battery comprising two discharge electrodes disposed between a halogen ion conductive solid electrolyte and a low temperature electrode.