TWI587564B - Proton exchange membrane fuel cell - Google Patents

Description

Proton exchange membrane fuel cell

This invention relates to a fuel cell, and more particularly to a proton exchange membrane fuel cell.

At present, almost all technology products need to rely on electricity to operate, so there are different ways of energy conversion to convert energy scattered in various substances or environments into electrical energy. In addition to environmentally-friendly solar power, wind power, and hydropower generation, other high-efficiency power generation or power storage devices (batteries) are also the subject of intense research in the industry in place of natural resources and the production of polluted oil and thermal power.

In the research topic of new power generation equipment, it is mainly based on high energy conversion efficiency, easy to use, environmental protection benefits and industrial application breadth. Although it has been able to be used in vehicle power instead of fossil fuels, such as lead-acid batteries, nickel-hydrogen batteries, and lithium batteries, it still has high cost and long charging time.

With current technology development, fuel cells are a highly efficient, clean power source that can be used as a vehicle power and information product. The fuel cell directly converts the chemical energy of fuels such as alcohol, natural gas and hydrogen into redox, and its high-efficiency energy conversion and relatively low environmental pollution have become the emerging power generation methods. In addition, when the fuel is used up, it can be used immediately by filling the fuel. Among them, hydrogen fuel cells are the most environmentally friendly. Hydrogen fuel cells use hydrogen and oxygen as fuels and oxidants, respectively, and produce only by-products, water. Hydrogen fuel cells usually have a proton exchange membrane, so they are called proton exchange membrane fuel cells.

However, the power generation efficiency of a proton exchange membrane fuel cell is generally related to a gas diffusion layer in which a gas diffusion layer is used to pass hydrogen and oxygen molecules, and water generated by the reaction must be prevented from hindering subsequent reactions. The design of the gas diffusion layer is an important issue in the design of proton exchange membrane fuel cells.

In order to improve the power generation efficiency of a proton exchange membrane fuel cell, the present invention provides a proton exchange membrane fuel cell.

Embodiments of the present invention provide a proton exchange membrane fuel cell having an anode and a cathode, and supplying hydrogen and oxygen to an anode and a cathode, respectively, for generating electric power. The fuel cell includes an anode gas diffusion layer and a cathode gas diffusion layer. The anode gas diffusion layer includes a first carbon support layer, a first microporous layer, a second microporous layer, and a third microporous layer. The first carbon support layer is adjacent to the anode. The first microporous layer has thirty percent by weight of Teflon (polytetrafluoroethylene) and is adjacent to the first carbon support layer. The second microporous layer has twenty-five percent by weight of Teflon and is adjacent to the first microporous layer. And the third microporous layer has Teflon in a weight percentage of twenty, adjacent to the second microporous layer. The cathode gas diffusion layer includes a second carbon carrier layer, a fourth microporous layer, a fifth microporous layer, and a sixth microporous layer. The second carbon support layer is adjacent to the cathode. The fourth microporous layer has thirty percent by weight of Teflon and is adjacent to the second carbon support layer. The fifth microporous layer has twenty-five percent by weight of Teflon and is adjacent to the fourth microporous layer. The sixth microporous layer has twenty percent by weight of Teflon and is adjacent to the fifth microporous layer.

In summary, the proton exchange membrane fuel cell provided by the embodiment of the present invention can generate electricity by using hydrogen and oxygen, and has high energy conversion efficiency because it directly converts chemical energy into electrical energy. In addition, the proton exchange membrane fuel cell provided by the embodiments of the present invention can be applied to maintain the stability of performance under different humidification conditions.

The detailed description of the present invention and the accompanying drawings are to be understood by the claims The scope is subject to any restrictions.

Please refer to FIG. 1. FIG. 1 is a schematic diagram of a proton exchange membrane fuel cell 1 according to an embodiment of the present invention. The proton exchange membrane fuel cell 1 has an anode and a cathode. The proton exchange membrane fuel cell 1 supplies hydrogen (H ₂ ) and oxygen (O ₂ ) to the anode catalyst layer 14 and the cathode catalyst layer 15, respectively, for generating electric power and supplying it to the load 18. The proton exchange membrane fuel cell 1 includes a proton exchange membrane 13, an anode catalyst layer 14, a cathode catalyst layer 15, an anode gas diffusion layer 16, and a cathode gas diffusion layer 17.

The proton exchange membrane 13 is located between the anode catalyst layer 14 and the cathode catalyst layer 15. The anode catalyst layer 14 is adjacent to the first side of the proton exchange membrane 13. The cathode catalyst layer 15 is adjacent to the second side of the proton exchange membrane 13. The anode gas diffusion layer 16 is adjacent between the anode catalyst layer 14 and the anode current collector plate 11, and the cathode gas diffusion layer 17 is adjacent between the cathode catalyst layer 15 and the cathode collector plate 12. In general, the proton exchange membrane fuel cell 1 is coated with a pressurized package. In the present embodiment, the anode collector plate 11 and the cathode collector plate 12 are plated with a gold plated surface, and the anode collector plate 11 and the cathode are used. The outer side of the current collector plate 12 covers all the components with a fiberglass board (not shown). The overall structure can be locked with screws, for example, with eight screws (not shown) fixed with a torque of 2.45 Newton-meter, respectively, but the invention is not limited. Therefore, the components in Figure 1 are actually stacked directly without gaps.

The proton exchange membrane 13 is used to pass protons (H ⁺ ). The anode catalyst layer 14 decomposes hydrogen (H ₂ ) into electrons and protons. The cathode catalyst layer 15 combines protons with oxygen (O ₂ ) to produce water (H ₂ O). The anode catalyst layer 14 and the cathode catalyst layer 15 of the present embodiment are attached to the proton exchange membrane 13, for example, Nafion manufactured by Nan-Ya company. 212 having an anode catalyst layer 14 and a cathode catalyst layer 15. The combination of the proton exchange membrane 13 and the anode catalyst layer 14 and the cathode catalyst layer 15 is generally referred to as a Membrane Electrode Assembly (MEA). In the present embodiment, the anode catalyst layer 14 and the cathode catalyst layer 15 have platinum (Pt) of 0.2 and 0.4 mg/cm 2 , respectively. The thickness of the anode catalyst layer 14 and the cathode catalyst layer 15 are both five to ten micrometers (μm). Platinum is a catalyst that accelerates the rate of reaction, and hydrogen is reduced to protons and electrons in the anode catalyst layer 14, and electrons are attracted to the anode 11 and then through the load 18. The reaction formula of the reduction reaction in the anode catalyst layer 14 is H ₂ → 2H ⁺ + 2e ^- . Protons pass through the proton exchange membrane 13 from the first side of the proton exchange membrane 13 to the second side of the proton exchange membrane 13. The protons oxidize in the cathode catalyst layer 15 with oxygen and electrons received by the cathode 12 to produce water, and the reaction formula is 4H ⁺ + 4e ^- + O ₂ → 2H ₂ O. Further, cerium oxide (SiO ₂ ) may be added to the anode catalyst layer 14 and the cathode catalyst layer 15 to maintain water in the anode catalyst layer 14 and the cathode catalyst layer 15, and thereby increase the reaction efficiency.

The anode gas diffusion layer 16 includes a first carbon carrier layer 161, a first microporous layer 162, a second layer second microporous layer 163, and a third layer third microporous layer 164. The first carbon carrier layer 161 is adjacent to the anode collector plate 11. The first microporous layer 162 has thirty percent by weight of polytetrafluoroethylene (PTFE) and is adjacent to the first carbon support layer 161. The second layer of second microporous layer 163 has twenty-five percent by weight of Teflon and is adjacent to the first microporous layer 162. The third layer of the third microporous layer 164 has a weight percentage of twenty Teflon and is adjacent between the second layer of the second microporous layer 163 and the anode catalyst layer 14.

The cathode gas diffusion layer 17 includes a second carbon carrier layer 171, a fourth microporous layer 172, a fifth microporous layer 173, and a sixth microporous layer 174. The second carbon carrier layer 171 is adjacent to the cathode collector plate 12. The fourth microporous layer 172 has thirty percent by weight of Teflon and is adjacent to the second carbon support layer 171. The fifth microporous layer 173 has twenty-five percent by weight of Teflon and is adjacent to the fourth microporous layer 172. The sixth microporous layer 174 has twenty percent by weight of Teflon and is adjacent between the fifth microporous layer 173 and the cathode catalyst layer 15.

The above weight percentage is defined as the weight percentage of Teflon coated on the substrate, for example, 100 grams of the substrate, and 130 grams after coating the Teflon, indicating that the weight percentage of the microporous layer is 30. %.

Referring back to FIG. 1, in the present embodiment, the anode gas diffusion layer 16 and the manner of fabrication thereof have various embodiments, and the present invention is not limited thereto. For example, the first carbonaceous layer 162 and the second microporous layer 163 may be completed by using the pure carbon paper 34BA produced by SGL as the first carbon carrier layer 161 and sequentially coating the Teflon three times. And a third microporous layer 164. Similarly, the cathode gas diffusion layer 17 uses the carbon paper 34BA as the second carbon carrier layer 171, and sequentially coats the Teflon three times to complete the fourth microporous layer 172, the fifth microporous layer 173, and the sixth microporous layer. 174. The carbon paper 34BA is a micro-porous layer structure, and the thickness of the Teflon from the first to sixth microporous layers coated by the carbon paper 34BA is 50 to 100 micrometers, respectively. Between μm). The different weight percentages of Teflon represent different hydrophobicity, and the anode gas diffusion layer 16 and the cathode gas diffusion layer 17 become gradient micropores according to the weight percentage of different Teflon. -porous layer, GMPL).

The hydrophobicity of the anode gas diffusion layer 16 and the cathode gas diffusion layer 17 may have different effects depending on the relative humidity (RH) during operation. In the present embodiment, the hydrophobicity of the cathode gas diffusion layer 17 is taken as an example. The hydrophobicity of the anode gas diffusion layer 16 is the same as that of the cathode gas diffusion layer 17. Please refer to FIG. 2A. FIG. 2A is a schematic diagram of the cathode gas diffusion layer 17 operating at a high relative humidity. At high relative humidity, both the cathode catalyst layer 15 and the second carbon support layer 171 contain a relatively high proportion of water. At this time, the oxygen molecules (O ₂ ) pass through the second carbon carrier layer 171 and pass through the Teflon of the fourth to sixth microporous layers (172 to 174) to reach the cathode catalyst layer 15. However, since the weight percentage of Teflon of the fourth to sixth microporous layers (172 to 174) is gradually decreased, the fourth microporous layer 172 is more hydrophobic than the fifth microporous layer 173, and the fifth micro The pore layer 173 is more hydrophobic than the sixth microporous layer 174. As a result, however, the sixth microporous layer 174 can still retain more water so that the cathode catalyst layer 15 can maintain a higher humidity.

The water droplets in Fig. 2A represent the distribution of water within the cathode gas diffusion layer due to the difference in hydrophobicity. Similarly, the gradient caused by the different hydrophobicities of the fourth to sixth microporous layers (172 to 174) makes water less likely to diffuse toward the cathode catalyst layer 15. Thus, at higher relative humidity, the cathode catalyst layer 15 is less susceptible to the accumulation of water produced and reduces the rate of reaction.

Please refer to FIG. 2B. FIG. 2B is a schematic diagram of the cathode gas diffusion layer 17 operating at low relative humidity. At low relative humidity, both the cathode catalyst layer 15 and the second carbon support layer 171 contain a lower proportion of water. At this time, the oxygen molecules (O ₂ ) also pass through the second carbon carrier layer 171 and pass through the Teflon of the fourth to sixth microporous layers (172 to 174) to reach the cathode catalyst layer 15 . However, since the weight percentage of Teflon of the fourth to sixth microporous layers (172 to 174) is gradually decreased, the fourth microporous layer 172 is more hydrophobic than the fifth microporous layer 173, and the fifth micro The pore layer 173 is more hydrophobic than the sixth microporous layer 174. This causes the water generated by the cathode gas diffusion layer 15 to be less likely to diffuse to the fourth microporous layer 172. Thereby, the cathode gas diffusion layer 15 can be maintained at a relatively high humidity. The water droplets in Fig. 2B represent the distribution of water within the cathode gas diffusion layer 17 due to the difference in hydrophobicity. Similarly, the gradient caused by the different hydrophobicities of the fourth to sixth microporous layers (172 to 174) makes it easier for water to stay in the cathode catalyst layer 15. Thus, at a lower relative humidity, the cathode catalyst layer 15 tends to retain water and avoid a decrease in the reaction rate.

Similarly, under high humidity, the anode catalyst layer 14 can be prevented from flowing back to maintain proper humidity; at low humidity, the water generated by the anode catalyst layer 14 can be moderately retained in the third microporous layer 164. To maintain high humidity.

Further, the proton exchange membrane fuel cell 1 can also increase the flow field structure inside the anode collector plate 11 and the cathode collector plate 12, as shown in FIG. The proton exchange membrane fuel cell 3 is substantially identical to the proton exchange membrane fuel cell 1 of Fig. 1 except that the increased anode flow field plate 38 and cathode flow field plate 39 are used to transfer hydrogen and oxygen, respectively, to the anode gas diffusion layer. 16 and a cathode gas diffusion layer 17. The use of a flow field allows the fuel (here hydrogen) and the oxidant (here oxygen) to pass uniformly into the fuel cell, improving the performance of the fuel cell. The anode flow field plate 38 and the cathode flow field plate 39 in this embodiment are composed of graphite, but the present invention is not limited thereto. Further, the anode flow field plate 38 and the cathode flow field plate 39 may be integrated into the anode current collector plate 11 and the cathode current collector plate 12. In other words, the anode current collecting plate 11 and the cathode current collecting plate 12 can be designed in such a manner that the fuel and the oxidizing agent can pass uniformly in accordance with the needs of the flow field. After the above description, those skilled in the art should be able to infer the implementation of the flow field plate, which will not be described here.

The test platform for testing the performance of the proton exchange membrane fuel cell 3 of the present embodiment is the 850C test machine of the Scribner Associates company, and the 850C test abutment can measure not only the polarization curve (voltage versus current density curve), It is also possible to measure AC-impedance and understand the water content accordingly. The ratio of hydrogen gas and oxygen gas input to the anode current collector plate 11 and the cathode current collector plate 12 is two to one. The temperature of the proton exchange membrane fuel cell 3 was 80 °C. The incoming gas (hydrogen and oxygen) has a predetermined relative humidity, and the relative humidity of the gas in the proton exchange membrane fuel cell 1 can be changed by changing the temperature of the incoming gas. The relative humidity of the gas entering the proton exchange membrane fuel cell 3 is between 100% and 5%, and the proton exchange membrane fuel cell 3 of the present embodiment and the microporous layer 34BC produced and commercialized using SGL are diffused as a gas. The performance of the layers of fuel cells is compared to understand the effects of different relative humidity on the fuel cell. In the data sheet, the gradient microporous layer GMPL represents the proton exchange membrane fuel cell 3 of the present embodiment, and the 34BC represents a fuel cell using the microporous layer 34BC.

Referring to FIG. 4A, FIG. 4A is a polarization diagram of the proton exchange membrane fuel cell 3 and the fuel cell using the microporous layer 34BC operating at high humidity according to an embodiment of the present invention. As can be seen from Fig. 4A, the proton exchange membrane fuel cell 3 of the present embodiment is more effective than the fuel cell using the microporous layer 34BC at a relative humidity (RH) of 100 to 25 percent. The gradient microporous layer formed by the anode gas diffusion layer 16 and the cathode gas diffusion layer 17 prevents water from being excessively accumulated in the anode catalyst layer 14 and the cathode catalyst layer 15. Referring to FIG. 4B again, FIG. 4B is a diagram showing a fixed-frequency AC impedance diagram of the proton exchange membrane fuel cell 3 and the fuel cell using the microporous layer 34BC at a relative humidity of one hundred percent according to an embodiment of the present invention. As can be seen from FIG. 4B, the mass transfer resistance of the proton exchange membrane fuel cell 3 of the present embodiment is lower than that of the fuel cell using the microporous layer 34BC.

Regarding the fuel cell performance at a lower relative humidity, please refer to FIG. 5A, which illustrates the polarization of the proton exchange membrane fuel cell 3 and the fuel cell using the microporous layer 34BC operating at low relative humidity according to an embodiment of the present invention. Graph. As can be seen from Fig. 5A, the proton exchange membrane fuel cell 3 of the present embodiment is more effective than the fuel cell using the microporous layer 34BC at 30 to 5 percent relative humidity. The gradient microporous layer allows water to remain in the anode catalyst layer 14 and the cathode catalyst layer 15 to maintain humidity and thereby increase the reaction rate.

Referring to FIG. 5B again, FIG. 5B is a diagram showing a fixed-frequency AC impedance diagram of the proton exchange membrane fuel cell 3 and the fuel cell using the microporous layer 34BC operating at a relative humidity of five percent according to an embodiment of the present invention. Fig. 5B shows that the mass transfer resistance of the proton exchange membrane fuel cell 3 of the present embodiment is lower than that of the fuel cell using the microporous layer 34BC. This result is also because the anode catalyst layer 14 and the cathode catalyst layer 15 of the proton exchange membrane fuel cell 3 of the present embodiment retain a large amount of water.

To understand the effect of different hydrophobicity on the performance of the fuel cell, the weight percent of Teflon in the first to sixth microporous layers was varied to form another gradient microporous layer, designated GMPL2. The weight percentage of the Teflon from the fourth to sixth microporous layers of the cathode gas diffusion layer 17 was changed to 35 percent, 25 percent, and 15 percent, respectively. Similarly, the weight percentage of the Teflon of the first to third microporous layers (162 to 164) of the anode gas diffusion layer 16 is 35 percent, 25 percent, and percentage, respectively. Fifteen.

Referring to FIG. 6A, FIG. 6A is a graph showing the polarization of the proton exchange membrane fuel cell 3 and the fuel cell using the microporous layer 34BC at a humidity of 100% according to an embodiment of the present invention. It can be seen from Fig. 6A that the efficiency of using the gradient microporous layer GMPL2 is the worst among the three, because the permeability is the worst among the three, and the Teflon is in the first to third microporous layers. Too much (162-164) prevents the transfer of water from the catalyst layer to the gas diffusion layer, which in turn affects the reaction rate. Actually, the gas permeability of the microporous layer 34BC and the gradient microporous layer GMPL and GMPL2 were 2.1, 1.3, and 0.4 (cubic centimeters per square centimeter ‧ seconds), respectively. The gas permeability decreases as the weight percentage of the Teflon increases, and as the thickness of the gas diffusion layer becomes thicker, the longer the diffusion distance, the lower the gas permeability. High gas permeability is beneficial for performance, especially in the mass transfer region. It can be seen that there is an ideal weight percentage of Teflon to optimize the performance of the fuel cell. In the present embodiment, the weight percentage of the Teflon of the gradient microporous layer GMPL is the most desirable value.

In order to understand the influence of the change in relative humidity, please refer to FIG. 6A and FIG. 6B simultaneously. FIG. 6B is a view of the proton exchange membrane fuel cell 3 and the fuel cell using the microporous layer 34BC operating at a humidity of 100% according to an embodiment of the present invention. The polarization curve of thirty. 6A and 6B, when the humidity of the anode catalyst layer 14 and the cathode catalyst layer 15 is low or dehydrated, the performance of the fuel cell is lowered. Since the fuel cell using the microporous layer GMPL can maintain water in the anode catalyst layer 34 and the cathode catalyst layer 35, it is superior in performance to the fuel cell using the microporous layer 34BC.

In order to further understand the performance of the fuel cell in a steady state, please refer to FIG. 7A and FIG. 7B simultaneously. FIG. 7A is a current density map of the proton exchange membrane fuel cell 3 operating at 0.6 volts and different relative humidity, FIG. 7B is The fuel cell using the microvoid layer 34BC operates at a current density map of 0.6 volts and different relative humidity. At a relative humidity of one hundred percent, the fuel cell using the microvoided layer 34BC has a current density of 700 mA/cm 2 , while the fuel cell using the gradient microporous layer GMPL has a current density of 800 mA/cm 2 . As previously described, using a gradient hydrophobic layer of gradient microporous layer GMPL, water can be excluded from the catalyst layer to the gas diffusion layer and can constitute a path for gas transport to the catalyst layer. At a relative humidity of seventy-five percent and fifty percent, the current density of the fuel cell using the gradient microporous layer GMPL is still superior to that of the fuel cell using the microporous layer 34BC. The same is true even when the relative humidity is twenty-five percent. It is worth noting that the undershoot of the current density is a transient phenomenon of flooding due to excessive water produced by the reaction, and causes the diffusion of gas at that time to be blocked by water.

In order to confirm the difference in current density at low relative humidity, please refer to FIG. 8A and FIG. 8B again. FIG. 8A is a current density map of the proton exchange membrane fuel cell 3 operating at 0.6 volts and low relative humidity, and FIG. 8B is a micro-porosity layer. The 34BC fuel cell operates at a current density map of 0.6 volts and low relative humidity. As can be seen from FIGS. 8A and 8B, the fuel cell using the gradient microporous layer GMPL still has a higher current density than the fuel cell using the microporous layer 34BC at low relative humidity. As previously described, the gradient microporous layer GMPL can retain water in the catalyst layer while avoiding a reduction in reaction rate.

According to an embodiment of the present invention, the above-described proton exchange membrane fuel cell can remove water from the catalyst layer while avoiding a large overflow of water to cause a decrease in efficiency. At the same time, at low relative humidity, the gradient microporous layer can keep water in the catalyst layer, avoiding a decrease in reaction rate. In addition, the gradient microporous layer also provides a gas transport path that allows the steady state current density to be greater than that of a conventional proton exchange membrane fuel cell.

The above description is only an embodiment of the present invention, and is not intended to limit the scope of the invention.

1. . . Proton exchange membrane fuel cell

11. . . Anode collector board

12. . . Cathode collector board

13. . . Proton exchange membrane

14. . . Anode catalyst layer

15. . . Cathode catalyst layer

16. . . Anode gas diffusion layer

17. . . Cathode gas diffusion layer

18. . . load

161. . . First carbon carrier layer

162. . . First microporous layer

163. . . Second microporous layer

164. . . Third microporous layer

171. . . Second carbon carrier layer

172. . . Fourth microporous layer

173. . . Fifth microporous layer

174. . . Sixth microporous layer

38. . . Anode flow field plate

39. . . Cathode flow field plate

1 is a schematic view of a proton exchange membrane fuel cell according to an embodiment of the present invention.

2A is a schematic view showing a cathode gas diffusion layer used in a high humidity according to an embodiment of the present invention.

2B is a schematic view showing the cathode gas diffusion layer used in a low humidity state according to an embodiment of the present invention.

3 is a schematic view of a proton exchange membrane fuel cell according to an embodiment of the present invention.

4A is a polarization diagram of the operation of a proton exchange membrane fuel cell and a conventional proton exchange membrane fuel cell at a high relative humidity according to an embodiment of the present invention.

4B is a graph showing a fixed-frequency AC impedance of a proton exchange membrane fuel cell and a conventional proton exchange membrane fuel cell at a relative humidity of 100% according to an embodiment of the present invention.

5A is a polarization diagram of a proton exchange membrane fuel cell and a conventional proton exchange membrane fuel cell operating at low relative humidity according to an embodiment of the present invention.

5B is a diagram showing a fixed-frequency AC impedance diagram of a proton exchange membrane fuel cell and a conventional proton exchange membrane fuel cell operating at a relative humidity of five percent according to an embodiment of the present invention.

6A is a graph showing polarization curves of a proton exchange membrane fuel cell and a conventional proton exchange membrane fuel cell operating at a humidity of 100% according to an embodiment of the present invention.

6B is a graph showing polarization curves of a proton exchange membrane fuel cell and a conventional proton exchange membrane fuel cell operating at a humidity of 30% according to an embodiment of the present invention.

Figure 7A is a graph of current density at 0.6 volts and different relative humidity using a conventional proton exchange membrane fuel cell.

7B is a current density diagram of a proton exchange membrane fuel cell operating at 0.6 volts and different relative humidity according to an embodiment of the present invention.

Figure 8A is a current density plot of a proton exchange membrane fuel cell operating at 0.6 volts and low relative humidity using a conventional gas diffusion layer.

Figure 8B is a current density diagram of a proton exchange membrane fuel cell operating at 0.6 volts and low relative humidity, in accordance with an embodiment of the present invention.

1. . . Proton exchange membrane fuel cell

11. . . Anode collector board

12. . . Cathode collector board

13. . . Proton exchange membrane

14. . . Anode catalyst layer

15. . . Cathode catalyst layer

16. . . Anode gas diffusion layer

17. . . Cathode gas diffusion layer

18. . . load

161. . . First carbon carrier layer

162. . . First microporous layer

163. . . Second microporous layer

164. . . Third microporous layer

171. . . Second carbon carrier layer

172. . . Fourth microporous layer

173. . . Fifth microporous layer

174. . . Sixth microporous layer

Claims (9)

A proton exchange membrane fuel cell having an anode and a cathode, and supplying hydrogen and oxygen to the anode and the cathode, respectively, for generating electric power, the fuel cell comprising: an anode gas diffusion layer comprising: a first a carbon carrier layer adjacent to the anode; a first microporous layer having a weight percentage of Teflon (polytetrafluoroethylene) adjacent to the first carbon support layer; and a second microporous layer having a weight percentage Twenty-five Teflon adjacent to the first microporous layer; and a third microporous layer having twenty percent Teflon adjacent to the second microporous layer, wherein the second microporous layer is located Between the first microporous layer and the third microporous layer; a cathode gas diffusion layer comprising: a second carbon carrier layer adjacent to the cathode; a fourth microporous layer having a weight percentage of Teflon Adjacent to the second carbon support layer; a fifth microporous layer having twenty-five percent by weight of Teflon adjacent to the fourth microporous layer; and a sixth microporous layer having twenty percent by weight of ferric fluoride a dragon adjacent to the fifth microporous layer, wherein the a five microporous layer is disposed between the fourth microporous layer and the sixth microporous layer, wherein the anode gas diffusion layer and the cathode gas diffusion layer of the fuel cell both form a gradient micro-porous structure And the hydrophobicity of the third microporous layer and the sixth microporous layer are respectively lower than the second microporous layer and the fifth microporous layer The hydrophobicity of the second microporous layer and the fifth microporous layer is lower than that of the first microporous layer and the fourth microporous layer, respectively. The proton exchange membrane fuel cell of claim 1, wherein the first microporous layer, the second microporous layer, the third microporous layer, the fourth microporous layer, and the fifth micro The thickness of the aperture layer and the sixth microporous layer are between fifty and one hundred micrometers, respectively. The proton exchange membrane fuel cell of claim 1, wherein the fuel cell further comprises: an anode flow field plate for transferring hydrogen to the anode gas diffusion layer; and a cathode flow field plate. Used to deliver oxygen to the cathode gas diffusion layer. A proton exchange membrane fuel cell according to claim 1, wherein the anode catalyst layer of the fuel cell and the cathode catalyst layer have platinum (Pt). The proton exchange membrane fuel cell of claim 4, wherein the anode catalyst layer of the fuel cell and the cathode catalyst layer have cerium oxide for holding water in the anode catalyst layer and the cathode catalyst layer. And increase the reaction rate accordingly. The proton exchange membrane fuel cell of claim 1, wherein the anode gas diffusion layer of the fuel cell and the first carbon carrier layer and the second carbon carrier layer of the cathode gas diffusion layer are carbon paper and have micro A micro-porous structure for passing hydrogen and oxygen. The proton exchange membrane fuel cell of claim 4, wherein the third microporous layer and the sixth microporous layer have higher water retention than the second microporous layer and the fifth microporous layer, the second micro The water retention of the pore layer and the fifth microporous layer is higher than the first microporous layer and the fourth microporous layer. Such as the proton exchange membrane fuel cell of claim 1 of the patent scope, the fuel electric When the cell is in a high humidity state, the anode gas diffusion layer and the cathode gas diffusion layer prevent water from filling the anode catalyst layer and the cathode catalyst layer, thereby preventing the reaction rate of the fuel cell from being lowered. The proton exchange membrane fuel cell of claim 1, wherein the anode gas diffusion layer and the cathode gas diffusion layer retain water in the anode catalyst layer and the cathode catalyst layer in a low humidity state, The reaction rate of the fuel cell is prevented from decreasing.