KR102205629B1 - Secondary battery using carbon dioxide and complex electric power generation system having the same - Google Patents

Abstract

According to the present invention, in a secondary battery capable of charging and discharging, in a secondary battery capable of charging and discharging, a first electrolyte that is an aqueous electrolyte accommodated in a first reaction space, and a cathode at least partially immersed in the first electrolyte A cathode portion having a; And an anode portion having a second electrolyte that is an aqueous electrolyte accommodated in the second reaction space, and an anode that is at least partially immersed in the second electrolyte, and in a discharging process, the temperature of the first electrolyte and the second electrolyte is It is maintained at 60°C to 80°C, and carbon dioxide gas is introduced into the first electrolyte, hydrogen ions and bicarbonate ions are generated by the reaction of water in the first electrolyte and the carbon dioxide gas, and the hydrogen ions and the cathode are There is provided a secondary battery in which electrons are bonded to generate hydrogen gas.

Description

A secondary battery that produces hydrogen using carbon dioxide and a complex power generation system equipped with the same {SECONDARY BATTERY USING CARBON DIOXIDE AND COMPLEX ELECTRIC POWER GENERATION SYSTEM HAVING THE SAME}

The present invention relates to a secondary battery, and more particularly, to provide a secondary battery using carbon dioxide and a complex power generation system having the same.

With the recent industrialization, emissions of greenhouse gases are continuously increasing, and carbon dioxide accounts for the largest proportion of greenhouse gases. Carbon dioxide emissions by industry type are the largest from energy sources such as power plants, and carbon dioxide from cement/steel/refining industries including power generation accounts for half of the world's generation. The field of carbon dioxide conversion/utilization can be largely divided into chemical conversion, biological conversion, and direct use, and the technical categories can be categorized into catalysts, electrochemistry, bioprocessing, light utilization, inorganic (carbonic acid), and polymers. Since carbon dioxide is generated in various industries and processes, and carbon dioxide reduction cannot be achieved with one technology, various approaches for carbon dioxide reduction are required.

Currently, the DOE (Department Of Energy) of the US Department of Energy is promoting multi-faceted technology development with interest in CCUS technology that combines CCS (Carbon Capture & Storage) and CCU (CC & Utilization) as a technology to reduce carbon dioxide. Although CCUS technology is recognized as an effective GHG reduction method, it faces the problems of high investment costs, the possibility of releasing harmful trapping agents to the atmosphere, and low technology maturity. In addition, from an energy and climate policy perspective, CCUS provides a means to substantially reduce GHG emissions, but there are many complementary items in the realization of the technology. Accordingly, there is a need to develop a new concept of breakthrough technology that more efficiently captures, stores, and utilizes carbon dioxide.

As a prior patent document related to the technical field of the present invention, Laid-Open Patent Publication No. 10-2015-0091834 discloses a liquid cathode portion including a sodium mixture solution and a cathode impregnated with a sodium-containing solution; An anode portion including a liquid organic electrolyte, an anode impregnated in the liquid organic electrolyte, and a negative active material positioned on the anode surface; And a solid electrolyte positioned between the cathode portion and the cathode portion. And a hydrogen discharging part connected to the cathode part to withdraw hydrogen generated from the cathode part during discharge to the outside.

Republic of Korea Patent Publication No. 10-2015-0091834 "Carbon dioxide capture secondary battery" (2015.08.12.)

An object of the present invention is to provide a secondary battery that produces hydrogen when discharged using carbon dioxide, which is a greenhouse gas, as a raw material.

Another object of the present invention is to provide a secondary battery with improved discharging capacity while producing hydrogen upon discharging with removal of carbon dioxide.

In order to achieve the above object of the present invention, according to an aspect of the present invention, in a secondary battery capable of charging and discharging, a first electrolyte that is an aqueous electrolyte accommodated in a first reaction space, and at least in the first electrolyte A cathode portion having a cathode partially locked; And an anode portion having a second electrolyte that is an aqueous electrolyte accommodated in the second reaction space, and an anode that is at least partially immersed in the second electrolyte, and in a discharging process, the temperature of the first electrolyte and the second electrolyte is It is maintained at 60°C to 80°C, and carbon dioxide gas is introduced into the first electrolyte, hydrogen ions and bicarbonate ions are generated by the reaction of water in the first electrolyte and the carbon dioxide gas, and the hydrogen ions and the cathode are There is provided a secondary battery in which electrons are bonded to generate hydrogen gas.

In order to achieve the above object of the present invention, according to another aspect of the present invention, in a secondary battery capable of charging and discharging, a first electrolyte that is an aqueous electrolyte accommodated in a first reaction space, and at least in the first electrolyte A cathode portion having a cathode partially locked; A carbon dioxide processing unit including the first electrolyte solution accommodated in an accommodation space communicating with the first reaction space; And an anode portion having a second electrolyte that is an aqueous electrolyte accommodated in the second reaction space, and an anode that is at least partially immersed in the second electrolyte, and in a discharging process, the temperature of the first electrolyte and the second electrolyte is It is maintained at 60°C to 80°C, and carbon dioxide gas is introduced into the first electrolyte in the accommodation space, hydrogen ions and bicarbonate ions are generated by a reaction of water of the first electrolyte and the carbon dioxide gas, and the cathode part The hydrogen ions and electrons of the cathode are combined to generate hydrogen gas, and the carbon dioxide processing unit separates non-ionized carbon dioxide gas from the carbon dioxide gas flowing into the first electrolyte in the accommodation space from the first electrolyte, A secondary battery is provided that is not supplied to the cathode.

In order to achieve the above object of the present invention, according to another aspect of the present invention, in a secondary battery capable of charging and discharging, an electrolyte solution which is an aqueous electrolyte accommodated in a reaction space; A cathode at least partially immersed in the electrolyte; And an anode in which at least a portion is immersed in the electrolyte, and in a discharging process, the temperature of the electrolyte is maintained at 60°C to 80°C, and carbon dioxide gas is introduced into the electrolyte, and the water of the electrolyte and the carbon dioxide gas react Hydrogen ions and bicarbonate ions are generated by this, and the hydrogen ions and electrons of the cathode are combined to generate hydrogen gas.

In order to achieve the above object of the present invention, according to another aspect of the present invention, in a secondary battery capable of charging and discharging, an aqueous electrolyte accommodated in a reaction space and a receiving space communicating with the reaction space includes an electrolyte; A cathode at least partially immersed in the electrolyte in the reaction space; And an anode at least partially immersed in the electrolyte in the reaction space, and in the discharging process, the temperature of the electrolyte is maintained at 60°C to 80°C, and carbon dioxide gas is introduced into the electrolyte solution in the accommodation space. Hydrogen ions and bicarbonate ions are generated by the reaction of water and the carbon dioxide gas, hydrogen ions and electrons of the cathode are combined in the reaction space to generate hydrogen gas, and carbon dioxide flowing into the aqueous electrolyte in the accommodation space A secondary battery is provided that prevents the non-ionized carbon dioxide gas from being supplied to the reaction space by being separated from the electrolyte in the accommodation space.

In order to achieve the above object of the present invention, according to another aspect of the present invention, the secondary battery for generating hydrogen by using carbon dioxide as fuel in the discharge process; A reformer for producing hydrogen-rich reformed gas from hydrogen-containing fuel and generating carbon dioxide as a by-product; A fuel cell receiving reformed gas produced from the reformer as fuel; And a carbon dioxide supply unit for supplying carbon dioxide generated by the reformer to the secondary battery.

In order to achieve the above object of the present invention, according to another aspect of the present invention, the secondary battery for generating hydrogen by using carbon dioxide as fuel in the discharge process; A reformer for producing hydrogen-rich reformed gas from a hydrogen-containing reactor; A fuel cell receiving reformed gas produced from the reformer as fuel; And a hydrogen supply unit additionally supplying hydrogen generated in the secondary battery as fuel of the fuel cell.

In order to achieve the above object of the present invention, according to another aspect of the present invention, the secondary battery for generating hydrogen by using carbon dioxide as fuel in the discharge process; A reformer for producing hydrogen-rich reformed gas from hydrogen-containing fuel and generating carbon dioxide as a by-product; A fuel cell receiving reformed gas produced from the reformer as fuel; A carbon dioxide supply unit for supplying carbon dioxide generated in the reformer to the secondary battery; And a hydrogen supply unit additionally supplying hydrogen generated in the secondary battery as fuel of the fuel cell.

According to the present invention, all the objects of the present invention described above can be achieved. Specifically, in a secondary battery that includes a cathode and a metal anode immersed in an aqueous electrolyte electrolyte, and generates hydrogen gas by introducing carbon dioxide gas into the electrolyte during the discharging process, the temperature of the electrolyte has a maximum current density of about twice that of room temperature. By maintaining the optimum temperature of 60 ℃ to 80 ℃ shown, the performance of the composite power generation system including the secondary battery and the secondary battery is greatly improved.

1 is a schematic diagram showing a discharge state of a secondary battery producing hydrogen using carbon dioxide according to a first embodiment of the present invention.
2 is a graph showing half-cell experiment results according to the temperature of an electrolyte solution for the secondary battery of the embodiment shown in FIG. 1.
3 is a graph showing an HER initiation region for each temperature in the graph of FIG. 2.
4 is a graph showing HER voltage for each temperature at a current density of 10 mA/cm 2 in the graph of FIG. 2.
5 is a graph showing a result of a single cell experiment according to a temperature of an electrolyte solution for the secondary battery of the embodiment shown in FIG. 1.
6 is a schematic diagram showing a discharge state of a secondary battery producing hydrogen using carbon dioxide according to a second embodiment of the present invention.
7 is a schematic diagram showing a discharge state of a secondary battery producing hydrogen using carbon dioxide according to a third embodiment of the present invention.
8 is a schematic diagram showing a discharge state of a secondary battery producing hydrogen using carbon dioxide according to a fourth embodiment of the present invention.
9 is a schematic diagram showing a discharge state of a secondary battery producing hydrogen using carbon dioxide according to a fifth embodiment of the present invention.
10 is a schematic diagram showing a discharge state of a secondary battery that produces hydrogen using carbon dioxide according to a sixth embodiment of the present invention.
11 is a schematic diagram showing a discharge state of a secondary battery producing hydrogen using carbon dioxide according to a seventh embodiment of the present invention.
12 is a schematic diagram showing a discharge state of a secondary battery that produces hydrogen using carbon dioxide according to an eighth embodiment of the present invention.
13 is a diagram showing a schematic configuration of a hybrid power generation system including a secondary battery for producing hydrogen using carbon dioxide according to an embodiment of the present invention.

Hereinafter, the configuration and operation of an embodiment of the present invention will be described in detail with reference to the drawings.

1 shows a configuration of a secondary battery for producing hydrogen using carbon dioxide according to a first embodiment of the present invention. Referring to FIG. 1, the secondary battery 100 includes a cathode unit 110, an anode unit 150, and a connection unit 190 connecting the cathode unit 110 and the anode unit 150. The secondary battery 100 produces hydrogen (H ₂ ), which is an eco-friendly fuel, by using carbon dioxide gas (CO ₂ ), which is a greenhouse gas, as a raw material in the discharge process.

The cathode part 110 includes a first reaction vessel 110a providing a first reaction space 111 therein, a first electrolyte 115 that is an aqueous electrolyte contained in the first reaction space 111, and a first A cathode 118 in which at least a portion of the electrolyte 115 is immersed is provided. As the first electrolyte 115, an alkaline aqueous solution (in this embodiment, one obtained by eluting CO ₂ from a strong basic solution of ₁ M KOH is used), sea water, tap water, distilled water, and the like may be used. In this embodiment, the temperature of the first electrolyte solution 115 is preferably 60 to 70°C, and most preferably 70°C. The cathode 118 is an electrode for forming an electric circuit, and may be carbon paper, carbon fiber, carbon felt, carbon cloth, metal foam, metal thin film, or a combination thereof, and a platinum catalyst may also be used. In the case of catalysts, in addition to platinum catalysts, all other catalysts that can be generally used as hydrogen evolution (HER) catalysts, such as carbon-based catalysts, carbon-metal-based complex catalysts, and perovskite oxide catalysts, are also included. A first inlet 112, a first outlet 113, and a first connector 114 communicating with the first reaction space 111 are formed in the first reaction vessel 110a. The first inlet 112 is positioned below the first reaction space 111 so as to be positioned below the water surface of the first electrolyte 115. The first outlet 113 is positioned above the first reaction space 111 so as to be positioned above the water surface of the first electrolyte 115. Carbon dioxide, which is used as a raw material in the discharging process, flows into the first reaction space 111 through the first inlet 112, and the first electrolyte 115 may also flow if necessary. The gas generated during the charging/discharging process is discharged to the outside through the first discharge port 113. Although not shown, the first inlet 112 and the first outlet 113 may be selectively opened and closed by a valve or the like during charging and discharging in a timely manner. The first connector 114 is located below the water surface of the first electrolyte 115, and the connection part 190 is connected to the first connector 114. In the cathode 110, a carbon dioxide elution reaction occurs during the discharge process.

The anode unit 150 includes a second reaction vessel 150a providing a second reaction space 151 therein, a second electrolyte solution 155 that is an aqueous electrolyte contained in the second reaction space 151, and a second An anode 158 in which at least a portion of the electrolyte 155 is immersed is provided. As the second electrolyte solution 155, a high concentration alkaline solution is used, for example, 1M KOH or 6M KOH may be used. In this embodiment, the temperature of the second electrolyte solution 155 is preferably 60°C to 80°C, and most preferably 70°C. The anode 158 is an electrode made of a metal material constituting an electric circuit. In this embodiment, it will be described that zinc (Zn) or aluminum (Al) is used as the anode 158. Further, as the anode 158, an alloy containing zinc or aluminum may be used. Additionally, vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), and copper (Cu) may be used as the anode 158, at which time acidic or basic The solution may be used as the second electrolyte solution 155. A second connector 154 communicating with the second reaction space 151 is formed in the anode part 150. The second connector 154 is located below the water surface of the second electrolyte 155, and the connector 190 is connected to the second connector 154.

The connection unit 190 includes a connection passage 191 connecting the cathode unit 110 and the anode unit 150, and an ion transfer member 192 installed inside the connection passage 191.

The connection passage 191 extends between the first connector 114 formed in the cathode part 110 and the second connector 154 formed in the anode part 150 so that the first reaction space 111 of the cathode part 110 ) And the second reaction space 151 of the anode unit 150 are communicated with each other. The ion transfer member 192 is installed inside the connection passage 191.

The ion transfer member 192 has a generally disk shape and is installed in a form that blocks the interior of the connection passage 191. The ion transfer member 192 has a porous structure and allows only the movement of ions between the cathode portion 110 and the anode portion 150. In this embodiment, it is described that the material of the ion transport member is glass, but the present invention is not limited thereto, and other materials having a porous structure may be used, and this also falls within the scope of the present invention. In this embodiment, the ion transfer member 192 has a pore size of 40 to 90 microns corresponding to G2 grade, 15 to 40 microns corresponding to G3 grade, 5 to 15 microns corresponding to G4 grade, Porous glass of 1 to 2 microns corresponding to G5 can be used. The ion transfer member 192 transfers only ions, thereby eliminating ionic imbalance occurring in the discharge process.

Now, the discharging process of the secondary battery 100 described above based on the configuration will be described in detail. 1 shows a discharge process of the secondary battery 100 together. Referring to FIG. 1, carbon dioxide gas is injected into the first electrolyte solution 115 through a first inlet 112, and a chemical elution reaction of carbon dioxide as shown in [Reaction Formula 1] is performed in the cathode unit 110.

[Scheme 1]

_{H 2 O (l) + CO} 2 (g) → H + (aq) + HCO 3 - (aq)

That is, in the cathode unit 110, the carbon dioxide gas (CO ₂ ) supplied to the cathode unit 110 is spontaneously reacted with water (H ₂ O) of the first electrolyte solution 115 to form a hydrogen cation (H ⁺ ) and bicarbonate. (HCO ₃ ^-) is generated.

In addition, in the cathode unit 110, an electrical reaction as shown in [Reaction Formula 2] is performed.

[Scheme 2]

^{2H + (aq) + 2e -} → H 2 (g)

That is, hydrogen cations at the cathode portion (110) (H ⁺⁾ are electron (e ^-) is a hydrogen gas (H ₂₎ generated receives. The generated hydrogen gas is discharged to the outside through the first outlet 113.

In addition, in the cathode unit 110, a complex hydrogen generation reaction as shown in the following [Scheme 3] is performed.

[Scheme 3]

_{2H 2 O (l) + 2CO} 2 (g) + 2e - → H 2 (g) + 2HCO 3 - (aq)

In addition, in the anode unit 150, when the anode 158 is zinc (Zn), an oxidation reaction as shown in [Reaction Formula 4] is performed.

[Scheme 4]

^{Zn + 4OH - → Zn (OH} ) 4 2 - + 2e - (E 0 = -1.25 V)

_{^{Zn (OH) 4 2 - →}} ZnO + H 2 O + 2OH -

As a result, when the anode 158 is zinc (Zn), the overall reaction equation performed in the discharge process is as follows [Reaction equation 5].

[Scheme 5]

Zn + 2CO _{2 ^{+ 2H 2 O + 2OH - →}} ZnO + 2HCO 3 - (aq) + H 2 (g) (E 0 = 1.25 V)

If, in the case where the anode 158 in the anode unit 150 is aluminum (Al), an oxidation reaction as shown in [Reaction Formula 5] is performed.

[Scheme 5]

^{Al + 3OH - → Al (OH} ) 3 ^{+ 3e - (E 0 = -2.31} V)

As a result, when the anode 158 is aluminum (Al), the overall reaction equation made in the discharging process is as follows [Scheme 7].

[Scheme 7]

2Al + 6CO _{2 ^{+ 6H 2 O + 6OH - →}} 2Al (OH) 3 _{^{+ 6HCO 3 - (aq) +}} 3H 2 (g) (E 0 = 2.31 V)

As a result, as can be seen from [Scheme 6] and [Scheme 7], hydrogen ions generated by carbon dioxide eluted from the first electrolyte 115 during discharge receive electrons from the cathode 18 Is reduced to, is discharged through the first discharge port 113, and the metal anode 158 is changed into an oxide form.

FIG. 2 is a graph showing the results of a half-cell experiment according to the temperature of the electrolyte solutions 115 and 155 for the secondary battery of the embodiment shown in FIG. 1, and FIG. 3 is a graph of FIG. It is a graph showing an area, and FIG. 4 is a graph showing HER voltage for each temperature at a current density of 10 mA/cm 2 in the graph of FIG. 2.

Referring to FIGS. 2 to 4, the HER initiation region improves from room temperature (RT) to a 45°C section as the temperature increases, and then gradually decreases after 45°C. In addition, when comparing the HER voltage at a current density of 10 mA/cm 2, the performance is improved as the temperature increases from room temperature (RT), but from 60° C., it tends to be saturated.

5 is a graph showing the results of a single cell experiment according to the temperature of the electrolyte solutions 115 and 155 for the secondary battery of the embodiment shown in FIG. 1. Referring to FIG. 5, it is confirmed that the cathode voltage at which the hydrogen generation reaction occurs shows a similar trend to the half-cell performance results shown in FIGS. 2 to 4. In the case of the anode voltage at which the oxidation reaction occurs, the oxidation result is improved due to the temperature increase, and it is confirmed that the electrode oxidation performance is saturated in the temperature range of 70°C to 80°C. Therefore, when considering the temperature-specific performance of the cathode and anode at the same time, it is confirmed to exhibit excellent performance in the electrolyte temperature range of 60°C to 80°C. In particular, the maximum current density is about 320mA/cm2 at a temperature of 70°C, at room temperature. It is confirmed to show the best performance by increasing about twice as much as about 160mA/cm2 measured. This is because the rate of hydrogen generation reaction and metal oxidation reaction is accelerated at the above temperature. At a temperature above 80°C, the carbon dioxide dissolution reaction rate is slowed and the amount of dissolution is small, resulting in a decrease in performance.

6 shows a discharging process of the configuration of a secondary battery that produces hydrogen using carbon dioxide according to a second embodiment of the present invention. Referring to FIG. 6, the secondary battery 100a includes a cathode unit 110, an anode unit 150, a connection unit 190 connecting the cathode unit 110 and the anode unit 150, and a carbon dioxide processing unit 120. ), and a carbon dioxide circulation supply unit 130, and a connection pipe 140 for communicating the cathode unit 110 and the carbon dioxide processing unit 120. Since the cathode unit 110, the anode unit 150, and the connection unit 190 are the same as those described in the embodiment shown in FIG. 1, detailed descriptions thereof will be omitted. The secondary battery 100a having the configuration shown in FIG. 6 also exhibits excellent performance in a temperature range of preferably 60°C to 80°C, more preferably 70°C, as described through FIGS. 2 to 5 do.

The carbon dioxide processing unit 120 includes a storage container 120a providing an accommodation space 121 therein, and a first electrolyte that is accommodated in the accommodation space 121 and is the same as the first electrolyte 115 of the cathode unit 110. An electrolyte solution 115 is provided. The receiving container 120a has a second inlet 122 through which carbon dioxide gas is introduced into the receiving space 121, a communication port 123 to which the connection pipe 140 is connected, and located above the receiving space 121. A second outlet 124 is formed.

The second inlet 122 is positioned above the communication port 123 in the receiving space 121, and is positioned below the water surface of the second outlet 124 and the first electrolyte 115. Carbon dioxide gas, which is used as a raw material in the discharge process, flows into the accommodation space 121 through the second inlet 122. The first electrolyte 115 may also be supplied through the second inlet 122 as needed. The second inlet 122 and the first outlet 113 may be selectively opened and closed at a suitable time by a valve or the like during charging and discharging.

The communication port 123 is located below the second inlet 122 in the receiving space 121, and a connection pipe 140 is connected to the communication port 123. The accommodation space 121 communicates with the first reaction space 111 through the communication port 123.

The second outlet 124 is positioned above the water surface of the second inlet 122 and the first electrolyte 115 in the receiving space 121. Carbon dioxide gas that has not been ionized because it is not dissolved in the first electrolyte solution 115 in the receiving space 121 through the second outlet 124 is discharged to the outside. The carbon dioxide gas discharged through the second outlet 124 is supplied to the second inlet 122 through the carbon dioxide circulation supply unit 130.

The carbon dioxide circulation supply unit 130 circulates the carbon dioxide gas discharged through the second outlet 224 to the second inlet 122 and supplies it again.

The connection pipe 140 connects the first inlet 112 of the first reaction space 111 and the communication port 123 of the accommodation space 121. The first reaction space 111 and the accommodation space 121 communicate with each other through a connection passage 141 formed inside the connection pipe 140.

The carbon dioxide gas that is not ionized because it is not dissolved in the first electrolyte 115 among the carbon dioxide introduced into the receiving space 121 of the carbon dioxide processing unit 120 through the second inlet 122 is the first reaction space of the cathode unit 110 Carbon dioxide gas that cannot move to 111 but rises and is collected in the space above the water surface of the first electrolyte 115 in the receiving space 121 and then discharged through the second discharge port 124 and discharged through the second discharge port 124 Is supplied to the receiving space 121 through the second inlet 122 by the carbon dioxide circulation supply unit 130 and is recycled. In addition, the carbon dioxide gas that is not ionized because it is not dissolved in the first electrolyte 115 among the carbon dioxide introduced into the receiving space 121 of the carbon dioxide processing unit 120 does not move to the first reaction space 111 of the cathode unit 110. Therefore, high-purity hydrogen in which carbon dioxide is not mixed may be discharged through the first discharge port 113.

The configuration of reference numerals not described in FIG. 6 is the same as the configuration indicated by the same reference numeral in the embodiment shown in FIG. 1.

7 is a schematic diagram illustrating a discharging process of a secondary battery according to a third embodiment of the present invention. Referring to FIG. 7, the secondary battery 200 includes a cathode part 210, an anode part 250, and a connection part 290 connecting the cathode part 210 and the anode part 250. The secondary battery 200 having the configuration shown in FIG. 7 also exhibits excellent performance in a temperature range of preferably 60°C to 80°C, more preferably 70°C as described through FIGS. 2 to 5. do.

The cathode part 210 includes a first reaction vessel 110a providing a first reaction space 111 therein, a first electrolyte solution 215 contained in the first reaction space 111, and a first electrolyte solution 215 ) Is provided with a cathode 118 that is at least partially submerged. As the first electrolyte 215, an aqueous potassium hydroxide solution (in this embodiment, one obtained by eluting CO ₂ in a strong basic solution of ₁ M KOH is used). Since the configurations of the first reaction vessel 110a and the cathode 118 are the same as the corresponding configurations in the embodiment shown in FIG. 1, detailed descriptions thereof will be omitted.

The anode unit 250 includes a second reaction vessel 150a providing a second reaction space 151 therein, a second electrolyte solution 255 contained in the second reaction space 151, and a second electrolyte solution 255. ) Is provided with an anode 158 that is at least partially submerged. As the second electrolyte 255, an aqueous potassium hydroxide solution is used, and, for example, 1M KOH or 6M KOH may be used. Since the configurations of the second reaction vessel 150a and the anode 158 are the same as the corresponding configurations in the embodiment shown in FIG. 1, detailed descriptions thereof will be omitted.

The connection part 290 includes a connection passage 191 connecting the cathode part 210 and the anode part 250, and an ion exchange membrane 292 installed inside the connection passage 191.

The connection passage 191 has the same configuration as the connection passage 191 shown in FIG. 1, and an ion exchange membrane 292 is installed inside the connection passage 191.

The ion exchange membrane 292 is installed to close the inside of the connection passage 191. The ion exchange membrane 292 allows only the movement of ions between the cathode portion 210 and the anode portion 250. Potassium ions (K ⁺ ) contained in the second electrolyte 255 are moved to the first electrolyte 215 by the ion exchange membrane 292. In this embodiment, as the ion exchange membrane 292, Nafion, which is a fluorine resin-based cation exchange membrane developed by DuPont, is used, but the present invention is not limited thereto, and potassium ions ( Anything that allows only the movement of K ⁺ ) is possible. The ion exchange membrane 292 transfers only ions, thereby eliminating ionic imbalance occurring in the discharge process.

The configuration of reference numerals not described in FIG. 7 is the same as the configuration indicated by the same reference numeral in the embodiment shown in FIG. 1.

8 is a schematic diagram showing a discharging process of a secondary battery according to a fourth embodiment of the present invention. Referring to FIG. 8, the secondary battery 200a includes a cathode part 210, an anode part 250, a connection part 290 connecting the cathode part 210 and the anode part 250, and a carbon dioxide processing part 120. ), and a carbon dioxide circulation supply unit 130, and a connection pipe 140 for communicating the cathode unit 210 and the carbon dioxide processing unit 120. The cathode part 210, the anode part 250, and the connection part 290 are the same as those described in the embodiment shown in FIG. 7, and the carbon dioxide processing part 120, the carbon dioxide circulation supply part 130, and the connection pipe 140 are Since the corresponding configuration shown in FIG. 6 is the same, a detailed description thereof will be omitted. The secondary battery 200a having the configuration shown in FIG. 8 also exhibits excellent performance in a temperature range of preferably 60°C to 80°C, more preferably 70°C as described through FIGS. 2 to 5 do. The configurations of reference numerals not described in FIG. 8 are the same as those indicated by the same reference numerals in the embodiment shown in FIG. 6.

9 is a schematic diagram illustrating a discharging process of a secondary battery according to a fifth embodiment of the present invention. Referring to FIG. 9, the secondary battery 300 includes a cathode part 210, an anode part 250, a cathode part 110, and a connection part 390 connecting the anode part 150. Since the cathode unit 210 and the anode unit 250 are the same as the corresponding configurations of the embodiment shown in FIG. 7, detailed descriptions thereof will be omitted. The secondary battery 300 having the configuration shown in FIG. 9 also exhibits excellent performance in a temperature range of preferably 60°C to 80°C, more preferably 70°C as described through FIGS. 2 to 5. do.

The connection part 390 includes a connection passage 191 connecting the cathode part 210 and the anode part 250, and an ion exchange membrane 392 installed inside the connection passage 291.

The connection passage 191 is the same as the connection passage 191 of the embodiment shown in FIG. 7, and an ion exchange membrane 392 is installed inside the connection passage 191.

The ion exchange membrane 392 is installed to close the inside of the connection passage 191. The ion exchange membrane 392 allows only the movement of ions between the cathode portion 210 and the anode portion 250. Hydroxide ions (OH ⁻ ) included in the first electrolyte solution 215 are moved to the second electrolyte solution 155 through the ion exchange membrane 392. In this embodiment, as the ion exchange membrane 392, Nafion, which is a fluorine resin-based cation exchange membrane developed by DuPont, is used, but the present invention is not limited thereto, and hydroxide ions ( all as long as it is possible that only) movement of the ^- OH. Hydroxide ions (OH ⁻ ) are transferred from the cathode unit 110 to the anode unit 150 by the ion exchange membrane 392, thereby eliminating ionic imbalance occurring in the discharge process.

The configuration of reference numerals not described in FIG. 9 is the same as the configuration indicated by the same reference numeral in the embodiment shown in FIG. 7.

10 is a schematic diagram showing a discharging process of a secondary battery according to a sixth embodiment of the present invention. Referring to FIG. 10, the secondary battery 300a includes a cathode part 210, an anode part 250, a connection part 390 connecting the cathode part 210 and the anode part 250, and a carbon dioxide treatment part 120. ), and a carbon dioxide circulation supply unit 130, and a connection pipe 140 for communicating the cathode unit 210 and the carbon dioxide processing unit 220. The cathode part 210, the anode part 250, and the connection part 390 are the same as those described in the embodiment shown in FIG. 9, and the carbon dioxide processing part 120, the carbon dioxide circulation supply part 130, and the connection pipe 140 are Since the corresponding configuration shown in FIG. 8 is the same, a detailed description thereof will be omitted. The secondary battery 300a having the configuration shown in FIG. 10 also exhibits excellent performance in a temperature range of preferably 60°C to 80°C, more preferably 70°C as described through FIGS. 2 to 5 Is done. The configuration of reference numerals not described in FIG. 10 is the same as the configuration indicated by the same reference numeral in the embodiment shown in FIG. 8.

In the embodiment shown in FIGS. 1 and 6, instead of the connection part 190, a salt bridge connecting the first electrolyte solution 115 and the second electrolyte solution 155 may be used, which is also within the scope of the present invention. Belong. When a salt bridge is used, a commonly used salt bridge internal solution such as potassium chloride (KCl) and sodium chloride (NaCl) may be used as the internal solution of the salt bridge. When the salt bridge is used, the discharge is in progress while the first electrolyte solution 115, the HCO ₃ ^- if it contains a (bicarbonate ions) is generated, the inner solution of the salt bridge is sodium chloride (NaCl) and sodium ion (Na ^+), as In order to balance the ions, sodium ions diffuse from the salt bridge and exist as ions in the form of an aqueous solution of sodium hydrogen carbonate (NaHCO ₃ ). Drying this solution additionally obtains a sodium carbonate solid product in the form of baking soda.

11 is a schematic diagram showing a discharge process of a secondary battery according to a ninth embodiment of the present invention. Referring to FIG. 11, the secondary battery 500 includes a reaction vessel 510 providing a reaction space 511 therein, an electrolyte solution 515 that is an aqueous electrolyte contained in the reaction space 511, and a reaction space 511. The cathode 118 is at least partially immersed in the electrolyte solution 115 and an anode 158 at least partially immersed in the aqueous electrolyte solution 115 in the reaction space 511. The secondary battery 500 produces hydrogen (H ₂ ), which is an eco-friendly fuel, by using carbon dioxide gas (CO ₂ ), which is a greenhouse gas, as a raw material in the discharge process.

The reaction vessel 510 provides a reaction space 511 in which the electrolyte solution 515 is contained and the cathode 118 and the anode 158 are accommodated. The reaction vessel 510 is provided with a first inlet 512 and a first outlet 513 communicating with the reaction space 511. The first inlet 512 is located below the reaction space 511 so as to be located below the water surface of the electrolyte solution 515. The first outlet 513 is positioned above the reaction space 511 so as to be positioned above the water surface of the electrolyte solution 515. Carbon dioxide gas, which is used as a raw material in the discharge process, flows into the reaction space 511 through the first inlet 512, and an electrolyte solution 515 may also be introduced if necessary. The gas generated in the charging/discharging process is discharged to the outside through the first discharge port 513. Although not shown, the first inlet 512 and the first outlet 513 may be selectively opened and closed by a valve or the like during charging and discharging in a timely manner. In the reaction space 511, a carbon dioxide elution reaction occurs during a discharge process.

The electrolyte solution 515, which is an aqueous electrolyte, is contained in the reaction space 511, and at least a portion of the cathode 118 and at least a portion of the anode 158 are immersed in the electrolyte solution 515. In this embodiment, it will be described that a basic solution or sea water is used as the electrolyte solution 115. The electrolyte solution 515 becomes weakly acidic by the carbon dioxide gas flowing through the first inlet 512 during the discharge process.

The cathode 118 is at least partially immersed in the electrolyte solution 515 in the reaction space 511. The cathode 118 is located relatively closer to the first inlet 512 than the anode 158 in the reaction space 511. The cathode 118 is an electrode for forming an electric circuit, and may be carbon paper, carbon fiber, carbon felt, carbon cloth, metal foam, metal thin film, or a combination thereof, and a platinum catalyst may also be used. In the case of catalysts, in addition to platinum catalysts, all other catalysts that can be generally used as hydrogen evolution (HER) catalysts, such as carbon-based catalysts, carbon-metal-based complex catalysts, and perovskite oxide catalysts, are also included. During discharge, a reduction reaction occurs in the cathode 118, and hydrogen is generated accordingly.

The anode 158 is at least partially immersed in the electrolyte solution 515 in the reaction space 511. The anode 158 is located relatively farther from the first inlet 512 than the cathode 118 in the reaction space 511. The anode 158 is an electrode made of a metal material constituting an electric circuit. In this embodiment, the anode 158 is used as vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), and nickel. (Ni), copper (Cu), aluminum (Al), or zinc (Zn) is described as being used. During discharge, an oxidation reaction occurs in the anode 158 according to a weakly acidic environment.

The secondary battery 500 of the configuration shown in FIG. 11 also exhibits excellent performance in a temperature range of preferably 60°C to 80°C, more preferably 70°C, as described through FIGS. 2 to 5. do.

Now, the discharging process of the secondary battery 100 described above based on the configuration will be described in detail. 11 shows a discharge process of the secondary battery 500 together. Referring to FIG. 11, during discharge, carbon dioxide gas is injected into an electrolyte solution 515 through a first inlet 512, and a chemical elution reaction of carbon dioxide as shown in [Reaction Formula 1] is performed in the reaction space 511. That is, the carbon dioxide supplied to the reaction chamber (511) (CO ₂₎ is water (H ₂ O) and spontaneous hydrogen cations through a chemical reaction (H ⁺⁾ and bicarbonate in the electrolyte (515) (HCO ₃ ^-) is generated.

In addition, in the cathode 118, an electrical reaction as in [Reaction Formula 2] is performed. That is, the cathode 118, the hydrogen cation in the vicinity (H ⁺⁾ are electron (e ^-) from the cathode (118) is takes the hydrogen (H ₂₎ gas is generated. The generated hydrogen (H ₂ ) gas is discharged to the outside through the first outlet 513.

In addition, around the cathode 118, a complex hydrogen generation reaction as shown in [Scheme 3] is performed.

In addition, in the anode 158, when the anode 158 is zinc (Zn), an oxidation reaction as shown in [Scheme 4] is performed.

As a result, when the anode 158 is zinc (Zn), the overall reaction equation made in the discharging process is the same as in [Scheme 5].

If the anode 158 is aluminum (Al), the oxidation reaction as in [Scheme 6] is performed.

As a result, when the anode 158 is aluminum (Al), the overall reaction equation made in the discharging process is the same as in [Scheme 7].

As a result, hydrogen ions generated by carbon dioxide eluted from the aqueous electrolyte electrolyte 515 during discharge receive electrons from the cathode 118 and are reduced to hydrogen gas, and are discharged through the first outlet 513, and the metal anode 158 changes to the form of oxide.

12 is a schematic diagram showing a discharging process of a secondary battery according to a tenth embodiment of the present invention. Referring to FIG. 12, the secondary battery 500a includes a reaction vessel 510 providing a reaction space 511 therein, an electrolyte solution 515 contained in the reaction space 511, and an electrolyte solution in the reaction space 511. A cathode 118 that is at least partially immersed in the 515, an anode 158 that is at least partially immersed in the electrolyte solution 515 in the reaction space 511, a carbon dioxide treatment unit 120, and a carbon dioxide circulation supply unit 130 and a connection pipe 140 connecting the reaction vessel 510 and the carbon dioxide treatment unit 120. The reaction vessel 510, the electrolyte solution 515, the cathode 118, and the anode 158 are the same as each of the corresponding configurations described in the embodiment shown in FIG. 11, and the carbon dioxide processing unit 120, the carbon dioxide circulation supply unit ( 130) and the connection pipe 140 are the same as each of the corresponding components shown in FIG. 6, and thus detailed descriptions thereof will be omitted. The secondary battery 500a of the configuration shown in FIG. 12 also exhibits excellent performance in a temperature range of preferably 60°C to 80°C, more preferably 70°C as described through FIGS. 2 to 5 Is done.

13 is a diagram showing a schematic configuration of a hybrid power generation system including a secondary battery for producing hydrogen using carbon dioxide according to an embodiment of the present invention. Referring to FIG. 13, the hybrid power generation system 1000 according to an embodiment of the present invention includes a secondary battery 100 that generates hydrogen gas (H ₂ ) using carbon dioxide gas (CO ₂ ) as a raw material during a discharge process, A reformer 300 that produces hydrogen-rich reformed gas from hydrogen-containing fuel and additionally generates carbon dioxide gas (CO ₂ ), a fuel cell 200 that generates electricity using hydrogen and oxygen, and a reformer 300 ), a carbon dioxide supply unit 400 supplying the carbon dioxide gas generated from the secondary battery 100 to the secondary battery 100, a hydrogen supply unit 500 supplying the hydrogen gas generated by the secondary battery 100 to the fuel cell, and the reformer 300 It includes a reformed gas supply unit 600 for supplying the reformed gas to the fuel cell 200.

The secondary battery 100 is the secondary battery 100 previously described with reference to FIG. 1, and uses carbon dioxide gas as a raw material in the discharging process and generates hydrogen gas as described in detail with reference to FIG. 1. The carbon dioxide gas supplied to the secondary battery 100 is carbon dioxide gas generated in the reformer 300 and supplied through the carbon dioxide supply unit 400. The hydrogen gas generated in the secondary battery 100 is supplied to the fuel cell 200 by the hydrogen supply unit 500. In the present embodiment, it is described that the secondary battery 100 shown in FIG. 1 is used in the complex power generation system, but unlike this, the secondary battery of the embodiment shown in FIGS. 6 to 12 may be used, and this is also the scope of the present invention. It belongs to.

The reformer 300 produces hydrogen-rich reformed gas from the hydrogen-containing fuel and additionally generates carbon dioxide gas. To this end, in this embodiment, it will be described that the reformer 300 is a methane-steam reformer that produces hydrogen (H ₂ ) by a reforming reaction between methane (CH ₄ ) and water vapor (H ₂ O).

The methane-steam reformer 300 occupies a significant portion of the hydrogen production process due to the advantages of inexpensive process cost and enabling mass production. The following [Scheme 8] relates to the reforming reaction of the methane-steam reformer 300.

[Scheme 8]

CH ₄ + H ₂ O -> CO + 3H ₂

CO + H ₂ O -> CO ₂ + H ₂

That is, carbon monoxide (CO) and hydrogen are produced by a chemical reaction between methane and water vapor, and hydrogen can be finally produced by a chemical reaction between carbon monoxide and water vapor continuously. Hydrogen produced in the methane-steam reformer 300 is supplied as fuel such as the fuel cell 200 by the reformed gas supply unit 600.

However, the methane-steam reformer 300 has many advantages described above, but as can be seen in [Reaction Equation 8], water vapor must be supplied from the outside for the operation of the process, and global warming as a by-product of hydrogen production There is a problem that carbon dioxide, which is the main cause of environmental problems, must be generated. However, in the case of the present invention, the carbon dioxide generated from the methane-steam reformer 300 is discharged to the atmosphere or transferred to a separate carbon dioxide capture and storage process, instead of being transferred to the carbon dioxide supply unit 400 for the discharge reaction of the secondary battery 100. By being delivered to the water-based secondary battery 100, it is possible to solve the problem of carbon dioxide generation, which is a necessary evil in the operation of the methane-steam reformer 300, as well as a system connecting the secondary battery 100 and the methane-steam reformer 300 As it is constructed, the redundant process may be omitted. Since the methane-steam reformer 300 is a known technology, a detailed description thereof will be omitted here.

The fuel cell 200 generates water and electric energy by a chemical reaction between hydrogen and oxygen. Although the fuel cell 200 has many advantages in terms of environment-friendliness, it must receive hydrogen extracted from the methane-steam reformer 300 or the like. However, in the case of the present invention, since the fuel cell 200 is constructed as a system with the secondary battery 100, the efficiency can be remarkably improved by receiving hydrogen gas generated during the discharging process of the secondary battery 100. .

The carbon dioxide supply unit 400 supplies carbon dioxide gas generated as a by-product in the reformer 300 to the secondary battery 100.

The hydrogen supply unit 500 supplies hydrogen gas generated as a by-product during the discharge process of the secondary battery 100 as fuel of the fuel cell 200.

The reformed gas supply unit 600 supplies the reformed gas produced in the reformer 300 as fuel of the fuel cell 200.

Although the present invention has been described through the above embodiments, the present invention is not limited thereto. The above embodiments may be modified or changed without departing from the spirit and scope of the present invention, and those skilled in the art will recognize that such modifications and changes also belong to the present invention.

100, 100a: secondary battery 110: cathode
111: first accommodation space 112: first inlet
113: first outlet 115: first aqueous solution
118: cathode 120: carbon dioxide processing unit
121: third accommodation space 122: second inlet
123: communication port 124: second outlet
130: carbon dioxide circulation supply unit 140: connection pipe
150: anode part 151: second accommodation space
155: second aqueous solution 158: anode
190: connection part 191: connection passage
192: ion transmission member

Claims (18)

In a secondary battery capable of charging and discharging,
A cathode portion including a first electrolyte solution, which is an aqueous electrolyte accommodated in the first reaction space, and a cathode at least partially immersed in the first electrolyte solution; And
An anode portion having a second electrolyte solution, which is an aqueous electrolyte accommodated in the second reaction space, and an anode at least partially immersed in the second electrolyte solution,
The material of the anode includes at least one metal selected from the group consisting of zinc, aluminum, vanadium, chromium, manganese, iron, cobalt, nickel and copper,
The first electrolyte and the second electrolyte are the same aqueous electrolyte,
During the discharging process, electrons are generated by the oxidation reaction of the metal in the anode part, and carbon dioxide gas is introduced into the first electrolyte in the cathode part, and hydrogen ions are reacted with the water in the first electrolyte and the carbon dioxide gas. And bicarbonate ions are generated, and the hydrogen ions and the electrons transferred to the cathode are combined to generate hydrogen gas,
In order to increase the maximum current density of the secondary battery, the temperature of the first electrolyte and the second electrolyte in the discharging process is 70° C. or higher to increase the hydrogen generation reaction of the cathode and the oxidation reaction of the anode, Secondary battery of 80 ℃ or less to maintain the reaction rate of dissolution of carbon dioxide. In a secondary battery capable of charging and discharging,
A cathode portion including a first electrolyte solution, which is an aqueous electrolyte accommodated in the first reaction space, and a cathode at least partially immersed in the first electrolyte solution;
A carbon dioxide processing unit including the first electrolyte solution accommodated in an accommodation space communicating with the first reaction space; And
An anode portion having a second electrolyte solution, which is an aqueous electrolyte accommodated in the second reaction space, and an anode at least partially immersed in the second electrolyte solution,
The material of the anode includes at least one metal selected from the group consisting of zinc, aluminum, vanadium, chromium, manganese, iron, cobalt, nickel and copper,
The first electrolyte and the second electrolyte are the same aqueous electrolyte,
During the discharging process, electrons are generated by the oxidation reaction of the metal in the anode part, and carbon dioxide gas is introduced into the first electrolyte in the cathode part, and hydrogen ions are reacted with the water in the first electrolyte and the carbon dioxide gas. And bicarbonate ions are generated, and the hydrogen ions and the electrons transferred to the cathode are combined to generate hydrogen gas,
In order to increase the maximum current density of the secondary battery, the temperature of the first electrolyte and the second electrolyte in the discharging process is 70° C. or higher to increase the hydrogen generation reaction of the cathode and the oxidation reaction of the anode, 80 ℃ or less to maintain the reaction rate of dissolution of carbon dioxide,
The carbon dioxide processing unit separates the non-ionized carbon dioxide gas of the carbon dioxide gas flowing into the first electrolyte in the accommodation space from the first electrolyte so that it is not supplied to the cathode. delete The method according to claim 1 or 2,
A connection passage for communicating the first reaction space and the second reaction space, and an ion transfer member having a porous structure installed in the connection passage to allow only movement of ions between the first electrolyte and the second electrolyte. Secondary battery. The method of claim 4,
The material of the ion transfer member is a secondary battery of glass. The method according to claim 1 or 2,
A secondary battery further comprising a connection passage for communicating the first reaction space and the second reaction space, and an ion exchange membrane installed in the connection passage to allow only movement of ions between the first electrolyte and the second electrolyte. . The method of claim 6,
The first electrolyte and the second electrolyte are potassium hydroxide aqueous solutions,
The ion exchange membrane is a secondary battery that allows potassium ions to move from the second reaction space to the first reaction space. The method of claim 6,
The first electrolyte and the second electrolyte are potassium hydroxide aqueous solutions,
The ion exchange membrane is a secondary battery that allows hydroxide ions to move from the first reaction space to the second reaction space. delete In a secondary battery capable of charging and discharging,
An electrolyte that is an aqueous electrolyte accommodated in the reaction space;
A cathode at least partially immersed in the electrolyte; And
It includes an anode at least partially immersed in the electrolyte,
The material of the anode includes at least one metal selected from the group consisting of zinc, aluminum, vanadium, chromium, manganese, iron, cobalt, nickel and copper,
In the discharging process, electrons are generated by the oxidation reaction of the metal at the anode, carbon dioxide gas is introduced into the electrolyte, hydrogen ions and bicarbonate ions are generated by the reaction of water in the electrolyte and the carbon dioxide gas, and the hydrogen Ions and the electrons moved to the cathode are combined to generate hydrogen gas,
In order to increase the maximum current density of the secondary battery, the temperature of the electrolyte solution in the discharging process is 70° C. or higher to increase the hydrogen generation reaction of the cathode and the oxidation reaction of the anode, and the dissolution reaction rate of carbon dioxide is maintained. Secondary battery below 80℃. In a secondary battery capable of charging and discharging,
An electrolyte that is an aqueous electrolyte accommodated in the reaction space and the accommodation space communicating with the reaction space;
A cathode at least partially immersed in the electrolyte in the reaction space; And
Includes an anode at least partially immersed in the electrolyte in the reaction space,
The material of the anode includes at least one metal selected from the group consisting of zinc, aluminum, vanadium, chromium, manganese, iron, cobalt, nickel and copper,
In the discharging process, electrons are generated by the oxidation reaction of the metal at the anode, carbon dioxide gas is introduced into the electrolyte, hydrogen ions and bicarbonate ions are generated by the reaction of water in the electrolyte and the carbon dioxide gas, and the hydrogen Ions and the electrons moved to the cathode are combined to generate hydrogen gas,
In order to increase the maximum current density of the secondary battery, the temperature of the electrolyte solution in the discharging process is 70° C. or higher to increase the hydrogen generation reaction of the cathode and the oxidation reaction of the anode, and the dissolution reaction rate of carbon dioxide is maintained. So that it is 80℃ or less,
A secondary battery configured to prevent non-ionized carbon dioxide gas from the carbon dioxide gas flowing into the aqueous electrolyte in the accommodation space from being separated from the electrolyte in the accommodation space and supplied to the reaction space. delete delete A secondary battery that generates hydrogen by using carbon dioxide as fuel during the discharge process;
A reformer for producing hydrogen-rich reformed gas from hydrogen-containing fuel and generating carbon dioxide as a by-product;
A fuel cell receiving reformed gas produced from the reformer as fuel; And
It includes a carbon dioxide supply unit for supplying the carbon dioxide generated in the reformer to the secondary battery,
The composite power generation system, wherein the secondary battery is a secondary battery according to any one of claims 1, 2, 10 and 11. The method of claim 14,
Hybrid power generation system further comprising a hydrogen supply unit for supplying the hydrogen generated in the secondary battery as fuel of the fuel cell. A secondary battery that generates hydrogen by using carbon dioxide as fuel during the discharge process;
A reformer for producing hydrogen-rich reformed gas from a hydrogen-containing reactor;
A fuel cell receiving reformed gas produced from the reformer as fuel; And
And a hydrogen supply unit for additionally supplying hydrogen generated in the secondary battery as fuel of the fuel cell,
The composite power generation system, wherein the secondary battery is a secondary battery according to any one of claims 1, 2, 10 and 11. A secondary battery that generates hydrogen by using carbon dioxide as fuel during the discharge process;
A reformer for producing hydrogen-rich reformed gas from hydrogen-containing fuel and generating carbon dioxide as a by-product;
A fuel cell receiving reformed gas produced from the reformer as fuel;
A carbon dioxide supply unit for supplying carbon dioxide generated in the reformer to the secondary battery; And
And a hydrogen supply unit for additionally supplying hydrogen generated in the secondary battery as fuel of the fuel cell,
The composite power generation system, wherein the secondary battery is a secondary battery according to any one of claims 1, 2, 10 and 11. The method of claim 17,
The reformer is a methane-steam reformer that produces hydrogen by a reforming reaction of methane (CH ₄ ) and water vapor (H ₂ O).

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