Phosphoric acid fuel cell and application thereof
By using non-conductive hydrophobic polymer film sealing rings in phosphoric acid fuel cells, the acid migration path and ion bypass current are blocked, the acid migration problem between single cells is solved, the stability and life of the stack are improved, and the maintenance cost is reduced.
Patent Information
- Application Number
- CN202510651600.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-20
- Publication Date
- 2025-08-22
AI Technical Summary
In existing phosphoric acid fuel cells, acid migration between single cells leads to electrode corrosion and cross-penetration of reaction gases, shortening battery life, and serious problems are especially under high reaction gas pressure.
A non-conductive hydrophobic polymer film sealing ring is used to extend outward beyond the edge of the isolation plate assembly to form a sealing structure, blocking the acid migration path and ionic bypass current, and combining it with the runner plate through the hot pressing process to ensure airtightness.
Effectively block acid migration, avoid electrode submersion and cross-penetration of reaction gases, improve stack stability and service life, and reduce maintenance costs.
Smart Images
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Abstract
Description
Technical Field
[0001] The present application belongs to the technical field of phosphoric acid fuel cells, and in particular relates to a phosphoric acid fuel cell and its application. Background Art
[0002] Phosphoric acid fuel cells are electrochemical devices that directly convert the chemical energy in fuel into electrical energy through an electrochemical reaction between hydrogen and oxygen in the presence of an electrocatalyst. Phosphoric acid fuel cells have the characteristics of high energy conversion efficiency, zero carbon emissions, low noise, and environmental friendliness. They are widely used in stationary power plants. The key components of phosphoric acid fuel cells are primarily composed of electrode plate assemblies and separator plate assemblies. The separator plate assembly's primary function is to provide a gas flow channel, isolate the reactant gases, prevent hydrogen and oxygen from mixing, conduct heat from the stack reaction, collect and transmit current, and support the electrode plate assembly. The stack is formed by stacking multiple groups of single cell assemblies, each of which includes an anode flow channel plate, an anode electrode, a matrix layer, a cathode electrode, and a cathode flow channel plate. Gas distribution within the stack is achieved by the external gas hood of the stack, which guides and redistributes the reactant gases.
[0003] Phosphoric acid fuel cells typically store excess acid to compensate for acid losses due to evaporation into the reactant gas stream, absorption into cell components, and reactions with internal cell materials. This excess acid is stored in a reservoir plate, which can be a separate component or have the storage function integrated into the matrix layer of the electrode plate assembly. Phosphoric acid exists in liquid form during normal fuel cell operation, and a common problem is acid migration from one cell to an adjacent cell.
[0004] The carbonaceous material used at the edges of phosphoric acid fuel cell separators can oxidize due to chemical reactions when exposed to the air inlet and outlet confluence areas. The degree of oxidation depends on the electrochemical potential, the partial pressure of water vapor, and the local temperature. Typically, oxidation is higher at the cell's air inlet edge due to the higher temperature than at the air outlet edge. Oxidation is generally less severe at the edges exposed to the fuel reactant gases. Oxidation of the carbon material causes the separator edge material to become hydrophilic, leading to the formation of an acid film along the separator assembly edge. This acid film creates an ion bypass current path along the separator assembly edge. This bypass path allows protons (hydrogen ions) to flow from the anode end of a cell substack along the edge to the cathode end. A substack is a group of cells, typically consisting of several individual cells, sandwiched between cooling plates in a fuel cell stack. This bypass current has two consequences: First, it lowers the electrolyte potential, causing carbon corrosion at the anode end of the substack. This carbon corrosion problem is particularly severe in fuel cells operating at higher reactant gas pressures, as the electrode potential at high pressures is higher than at atmospheric pressure. Second, bypass currents can also cause anions (dihydrogen phosphate) to migrate from the cathode to the anode of a substack. Hydrogen ions and dihydrogen phosphate ions combine at the anode end of the substack, causing acid to be transported from the cathode to the anode of the substack—in other words, acid migration from one cell to the adjacent cell. This acid migration can have serious consequences: cells at the cathode end of the substack, starved of acid, experience reactant gas cross-permeation and lead to failure. Cells at the anode end of the substack, overloaded with acid, experience electrode flooding, further degrading performance and potentially leading to failure. This acid migration from one cell to another significantly shortens the fuel cell's lifespan, and is particularly severe for cells with smaller electrolyte reserves. Managing the liquid electrolyte within the fuel cell presents a significant design challenge.
[0005] Therefore, an effective design method is needed to avoid the migration of acid between single cells, improve the performance of the battery stack, and further extend the service life of the battery stack. Summary of the Invention
[0006] The purpose of the present application is to provide a phosphoric acid fuel cell and its application, aiming to solve the problem of acid migration between single cells in the prior art, avoid the cross-penetration of reaction gases caused by acid deficiency in single cells, and avoid the problem of electrode flooding due to excessive acid in single cells, which further causes the performance of single cells to deteriorate and affects the battery life.
[0007] To achieve the above application objectives, the technical solutions adopted in this application are as follows:
[0008] In a first aspect, the present application provides a phosphoric acid fuel cell that generates current through an electrochemical reaction between hydrogen and air, comprising:
[0009] A plurality of electrode plate assemblies, each electrode plate assembly comprising an anode electrode, a cathode electrode, and a matrix layer sandwiched between the anode electrode and the cathode electrode, wherein the matrix layer is filled with a liquid acidic electrolyte;
[0010] A plurality of separator plate assemblies, each separator plate assembly comprising an anode flow channel plate and a cathode flow channel plate, wherein the flat sides of the anode flow channel plate and the cathode flow channel plate are bonded by heat pressing with a sealing ring to form a sealed structure;
[0011] The sealing ring is made of a non-conductive hydrophobic polymer film and extends outward beyond at least one edge of the isolation plate assembly to physically block the acid migration path and the ion bypass current.
[0012] In some embodiments, one side of the anode flow channel plate is provided with a hydrogen flow channel groove and a sealing area, and the other side is a plane; one side of the cathode flow channel plate is provided with an air flow channel groove and a sealing area, and the other side is a plane.
[0013] In some embodiments, the hydrogen flow channel groove and the air flow channel groove are separated by a flow channel ridge.
[0014] In some embodiments, the sealing ring extends outwardly beyond the edge of the isolation plate assembly by a distance of 0.05 mm to 2.0 mm.
[0015] In some embodiments, the non-conductive hydrophobic polymer film is selected from polytetrafluoroethylene or fluorinated ethylene propylene.
[0016] In some embodiments, an edge of the separator plate assembly is vertically aligned with an edge of the electrode plate assembly.
[0017] In some embodiments, the planar sides of the anode flow channel plate and the cathode flow channel plate are combined with a sealing ring through a hot pressing process to form an airtight isolation structure.
[0018] In some embodiments, the extended portion of the seal ring blocks a fluid film formed by the acid along the edge of the separator plate assembly, thereby eliminating an ion bypass current path.
[0019] In a second aspect, the present application discloses a phosphoric acid fuel cell stack, comprising the phosphoric acid fuel cell described above.
[0020] The phosphoric acid fuel cell provided in the first aspect of the present application includes a plurality of electrode plate assemblies and a plurality of separator plate assemblies, wherein each separator plate assembly includes an anode flow channel plate and a cathode flow channel plate, and the planar sides of the anode flow channel plate and the cathode flow channel plate are bonded by heat-pressing a sealing ring to form a sealing structure; wherein the sealing ring is made of a non-conductive hydrophobic polymer film and extends outward beyond at least one edge of the separator plate assembly to physically block the acid migration path and the ion bypass current. This solves the problem of acid migration between single cells, avoids cross-penetration of reaction gases due to acid deficiency in single cells, and avoids electrode flooding due to excessive acid in single cells. It is conducive to eliminating ion bypass current, thereby significantly reducing acid loss or acid accumulation between single cells, avoiding electrode flooding or cross-penetration of reaction gases, and improving the stability and service life of the fuel cell stack; the design is simple, the production cost is low, and it is conducive to wide application.
[0021] The second aspect of the present application provides a fuel cell stack comprising the above-mentioned phosphoric acid fuel cell. By integrating an innovative isolation plate assembly design, the energy conversion efficiency and service life of the fuel cell stack are significantly improved, maintenance costs are reduced, and the stack is suitable for high-reliability application scenarios such as fixed power stations. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.
[0023] Figure 1 This is a schematic diagram of a battery stack provided in an embodiment of the present application;
[0024] Figure 2 This is a schematic diagram of acid migration between single cells in a battery stack provided by an embodiment of the present application;
[0025] Figure 3 is a schematic diagram of an isolation plate assembly provided in an embodiment of the present application;
[0026] Figure 4 is a schematic side view of an isolation plate assembly provided in an embodiment of the present application;
[0027] Figure 5 This is a schematic diagram of the hydrogen side of the isolation plate assembly provided in Example 1 of the present application;
[0028] Figure 6 This is a schematic diagram of the air side of the isolation plate assembly provided in Example 1 of the present application;
[0029] Figure 7 This is a schematic diagram of the sealing ring of the isolation plate assembly provided in Example 1 of the present application;
[0030] Figure 8 This is a schematic diagram of the hydrogen side of the isolation plate assembly provided in Example 2 of the present application;
[0031] Figure 9 This is a schematic diagram of the air side of the isolation plate assembly provided in Example 2 of the present application;
[0032] Figure 10 This is a schematic diagram of the sealing ring of the isolation plate assembly provided in Example 2 of the present application. DETAILED DESCRIPTION
[0033] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, the present application is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.
[0034] In this application, the term "and / or" describes the relationship between associated objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. A and B can be singular or plural. The character " / " generally indicates that the associated objects are in an "or" relationship.
[0035] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.
[0036] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. Some or all of the steps can be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.
[0037] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The singular forms "a", "an" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise.
[0038] The weights of the relevant components mentioned in the examples of this application may not only refer to the specific content of each component, but also represent the weight ratio between the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the examples of this application, it is within the scope disclosed in the examples of this application. Specifically, the mass described in the examples of this application may be a mass unit known in the chemical industry, such as μg, mg, g, kg, etc.
[0039] The terms "first" and "second" are used solely for descriptive purposes to distinguish objects, such as substances, from one another and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the technical features being referred to. For example, a first XX could also be referred to as a second XX, and similarly, a second XX could also be referred to as a first XX, without departing from the scope of the embodiments of this application. Thus, features defined as "first" or "second" may explicitly or implicitly include one or more of such features.
[0040] A first aspect of an embodiment of the present application provides a phosphoric acid fuel cell that generates current through an electrochemical reaction between hydrogen and air, comprising:
[0041] A plurality of electrode plate assemblies, each electrode plate assembly comprising an anode electrode, a cathode electrode, and a matrix layer sandwiched between the anode electrode and the cathode electrode, wherein the matrix layer is filled with a liquid acidic electrolyte;
[0042] A plurality of separator plate assemblies, each separator plate assembly comprising an anode flow channel plate and a cathode flow channel plate, wherein the flat sides of the anode flow channel plate and the cathode flow channel plate are bonded by heat pressing with a sealing ring to form a sealed structure;
[0043] The sealing ring is made of a non-conductive hydrophobic polymer film and extends outward beyond at least one edge of the isolation plate assembly to physically block the acid migration path and the ion bypass current.
[0044] The phosphoric acid fuel cell provided in the first aspect of the embodiment of the present application includes a plurality of electrode plate assemblies and a plurality of separator plate assemblies, wherein each separator plate assembly includes an anode flow channel plate and a cathode flow channel plate, and the planar sides of the anode flow channel plate and the cathode flow channel plate are bonded by heat-pressing with a sealing ring to form a sealing structure; wherein the sealing ring is made of a non-conductive hydrophobic polymer film and extends outward beyond at least one edge of the separator plate assembly to physically block the acid migration path and the ion bypass current. This solves the problem of acid migration between single cells, avoids cross-penetration of reaction gases due to acid deficiency in single cells, and avoids electrode flooding due to excessive acid in single cells. It is conducive to eliminating ion bypass current, thereby significantly reducing acid loss or acid accumulation between single cells, avoiding electrode flooding or cross-penetration of reaction gases, and improving the stability and service life of the fuel cell stack; the design is simple, the production cost is low, and it is conducive to wide application.
[0045] In some embodiments, the anode channel plate has a hydrogen flow groove and a sealing area on one side, and a flat surface on the other side. The cathode channel plate has an air flow groove and a sealing area on one side, and a flat surface on the other side. The hydrogen flow grooves of the anode channel plate and the air flow grooves of the cathode channel plate optimize gas distribution efficiency, while the sealing area on the flat surface is thermally bonded to form a stable seal, effectively isolating hydrogen and oxygen, preventing gas crosstalk, and improving the utilization rate of the reactant gases.
[0046] In some embodiments, the hydrogen flow channel groove and the air flow channel groove are separated by a flow channel ridge.
[0047] In some embodiments, the sealing ring extends outward beyond the edge of the separator plate assembly by 0.05 mm to 2.0 mm. This distance (0.05 mm to 2.0 mm) has been optimized to fully cover potential acid migration paths while avoiding compromising the compactness of the fuel cell stack due to excessive material thickness or extension, achieving a balance between efficient blocking and lightweight design.
[0048] In some embodiments, the non-conductive hydrophobic polymer film is selected from polytetrafluoroethylene or fluorinated ethylene propylene. Using polytetrafluoroethylene (PTFE) or fluorinated ethylene propylene (FEP) as the sealing material is both hydrophobic and chemically inert, allowing for long-term resistance to acidic environments. This prevents performance degradation of the sealing ring due to corrosion or moisture absorption, ensuring a long-term, stable physical blocking effect.
[0049] In some embodiments, the edge of the separator plate assembly is vertically aligned with the edge of the electrode plate assembly, thereby improving the overall sealing reliability of the fuel cell stack.
[0050] In some embodiments, the planar sides of the anode and cathode flow channel plates are bonded to a sealing ring through a hot pressing process to form an airtight isolation structure. This hot pressing process, combined with the sealing ring, creates an airtight isolation structure, avoiding the risks of conductivity or corrosion that may be introduced by traditional adhesives. It also strengthens the bond between the sealing ring and the flow channel plates, preventing interfacial separation under high temperatures or pressure fluctuations.
[0051] In some embodiments, the extended portion of the seal ring blocks the acid film formed along the edge of the separator assembly, thereby eliminating the path for ion bypass current. This extended portion directly blocks the formation of the acid film, eliminating the physical path for ion bypass current and extending the operational life of the fuel cell stack.
[0052] A second aspect of an embodiment of the present application discloses a phosphoric acid fuel cell stack, including the phosphoric acid fuel cell described above.
[0053] The second aspect of the present application provides the above-mentioned phosphoric acid fuel cell stack, which significantly improves the energy conversion efficiency and service life of the battery and reduces maintenance costs through the integrated innovative isolation plate assembly design, and is suitable for high-reliability application scenarios such as fixed power stations.
[0054] In some embodiments, phosphoric acid fuel cells such as Figure 1 As shown, 10 is the stack body, which is composed of several stacked single battery cells, with 1 and 2 each representing a single battery cell. 11 is the separator plate assembly, 12 is the anode flow plate (hydrogen), 13 is the cathode flow plate (air), 14 is the cathode electrode, 15 is the matrix layer, 16 is the anode electrode, 17 is the sealing area, 18 is the air flow area, and 19 is the hydrogen flow area. 14, 15, and 16 form the electrode plate assembly, and 12 and 13 form the separator plate assembly.
[0055] In some embodiments, the isolation plate assembly is Figure 3 and Figure 4 As shown, 11 is a separator assembly, 12 is an anode flow channel plate, 13 is a cathode flow channel plate, and 20 is a sealing ring. The sealing ring can be designed and optimized according to actual conditions.
[0056] The following describes the details in conjunction with specific embodiments.
[0057] Example 1
[0058] like Figures 5 to 7 As shown, this embodiment provides a separator design for a phosphoric acid fuel cell. Hydrogen flows into the anode flow channel plate 12 from one side of the flow channel and flows out from the other side of the flow channel. The flow channel plate is square, with a side length of 160mm and a thickness of 1mm. Air flows into the cathode flow channel plate 13 from one side of the flow channel and flows out from the other side of the flow channel. The flow channel plate is square, with a side length of 160mm and a thickness of 1mm. The sealing ring is square, with an outer length of 164mm and an inner length of 150mm. The thickness of the sealing ring is about 0.05mm, and the sealing ring material is polytetrafluoroethylene (PTFE). The sealing ring extends outward beyond the edges of the four sides of the separator plate assembly, and the extension distance beyond the edge is 2.0mm. The portion of the sealing ring extending beyond the edge provides a physical blockage of the acid migration route, prevents the formation of an acid fluid film at the edge of the separator plate assembly, and cuts off the ion bypass current path formed along the edge of the battery separator plate assembly. This further ensures the stability of the fuel cell performance and extends the service life of the stack.
[0059] Example 2
[0060] like Figures 8 to 10As shown, this embodiment provides a separator design for a phosphoric acid fuel cell. Hydrogen flows into the anode flow channel plate 12 from one side of the flow channel and flows out from the other side of the flow channel. The flow channel plate is square, with a side length of 160mm and a thickness of 1mm. Air flows into the cathode flow channel plate 13 from one side of the flow channel and flows out from the other side of the flow channel. The flow channel plate is square, with a side length of 160mm and a thickness of 1mm. The sealing ring is rectangular. The outer length of the sealing ring adjacent to the flow channel opening of the cathode flow channel plate is 160mm and the inner length is 150mm. The outer length of the sealing ring adjacent to the flow channel opening of the anode flow channel plate is 164mm and the inner length is 150mm. The thickness of the sealing ring is approximately 0.05mm, and the sealing ring material is polytetrafluoroethylene (PTFE). The sealing ring extends outward at the edges of the flow channel inlet and outlet of the cathode flow channel plate, and the extension distance beyond the edge is 2.0mm. The seal extends beyond the edge of the seal to physically block the acid migration path at the edge of the cathode channel plate, preventing the formation of an acid film at the edge of the separator plate assembly and cutting off the ion bypass current path formed along the edge of the battery separator plate assembly. This further ensures the stability of fuel cell performance and extends the service life of the stack.
[0061] In summary, the phosphoric acid fuel cell provided by the embodiment of the present application includes a plurality of electrode plate assemblies and a plurality of separator plate assemblies, wherein each separator plate assembly includes an anode flow channel plate and a cathode flow channel plate, and the planar sides of the anode flow channel plate and the cathode flow channel plate are hot-pressed and bonded to form a sealing structure through a sealing ring; wherein the sealing ring is made of a non-conductive hydrophobic polymer film and extends outward beyond at least one edge of the separator plate assembly to physically block the acid migration path and the ion bypass current. This solves the problem of acid migration between single cells, avoids cross-penetration of reaction gases due to acid deficiency in single cells, and avoids electrode flooding due to excessive acid in single cells. It is conducive to eliminating ion bypass current, thereby significantly reducing acid loss or acid accumulation between single cells, avoiding electrode flooding or cross-penetration of reaction gases, and improving the stability and service life of the fuel cell stack; the design is simple, the production cost is low, and it is conducive to wide application.
[0062] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.
Claims
1. A phosphoric acid fuel cell that generates current through an electrochemical reaction between hydrogen and air, characterized in that: include: A plurality of electrode plate assemblies, each electrode plate assembly comprising an anode electrode, a cathode electrode, and a matrix layer sandwiched between the anode electrode and the cathode electrode, wherein the matrix layer is filled with a liquid acidic electrolyte; A plurality of separator plate assemblies, each separator plate assembly comprising an anode flow channel plate and a cathode flow channel plate, wherein the flat sides of the anode flow channel plate and the cathode flow channel plate are bonded by heat pressing with a sealing ring to form a sealed structure; The sealing ring is made of a non-conductive hydrophobic polymer film and extends outward beyond at least one edge of the isolation plate assembly to physically block the acid migration path and the ion bypass current.
2. The phosphoric acid fuel cell according to claim 1, characterized in that One side of the anode flow channel plate is provided with a hydrogen flow channel groove and a sealing area, and the other side is a plane; one side of the cathode flow channel plate is provided with an air flow channel groove and a sealing area, and the other side is a plane.
3. The phosphoric acid fuel cell according to claim 2, characterized in that The hydrogen flow channel groove and the air flow channel groove are separated by a flow channel ridge.
4. The phosphoric acid fuel cell according to claim 1, characterized in that The distance that the sealing ring extends outward beyond the edge of the isolation plate assembly is 0.05 mm to 2.0 mm.
5. The phosphoric acid fuel cell according to claim 1, characterized in that The non-conductive hydrophobic polymer film is selected from polytetrafluoroethylene or fluorinated ethylene propylene.
6. The phosphoric acid fuel cell according to claim 1, characterized in that The edges of the separator plate assembly are vertically aligned with the edges of the electrode plate assembly.
7. The phosphoric acid fuel cell according to claim 1, characterized in that The plane sides of the anode flow channel plate and the cathode flow channel plate are combined with the sealing ring through a hot pressing process to form an airtight isolation structure.
8. The phosphoric acid fuel cell according to claim 1, characterized in that The extended portion of the seal ring blocks the fluid film formed by the acid along the edge of the separator plate assembly, thereby eliminating the ion bypass current path.
9. A phosphoric acid fuel cell stack, characterized in that: A phosphoric acid fuel cell comprising the phosphoric acid fuel cell according to any one of claims 1 to 8.