Fuel cell polar plate structure design method, fuel cell polar plate and fuel cell thereof

Abstract

The invention discloses a fuel cell polar plate structure design method, a fuel cell polar plate and a fuel cell thereof.The fuel cell polar plate structure design method comprises the steps that the relation between polar plate structure parameters and the fluid flow velocity is determined; carrying out preliminary design on the structural parameters; determining the flow of fluid flowing through the polar plate; determining the flow area of the fluid; determining a flow rate of the fluid; judging whether the flow velocity meets a set threshold value or not; if yes, the flow field design of the polar plate is reasonable; and if not, re-designing the structural parameters of the polar plate. According to the method, more comprehensive design parameters are extracted, the relation between the fluid flow velocity and the structural parameters of the fuel cell polar plate is established, the constraint relation of the parameters is comprehensively weighed, the logic of polar plate structural design is cleared, primary and secondary design is distinguished, and design development of the polar plate and comparison and optimization of different design schemes are guided.

Description

Technical Field

[0001] The invention belongs to the technical field of fuel cells, and in particular relates to a fuel cell plate structure design method, a fuel cell plate and a fuel cell thereof. Background Art

[0002] A fuel cell is a power generation device that converts the chemical energy in fuel and oxidant directly into electrical energy. When a fuel cell is working, the anode reactant (such as hydrogen) is input to the anode electrode side, and the cathode reactant (such as oxygen) is input to the cathode electrode side. The anode reactant and the cathode reactant undergo a redox reaction at the interface between the electrode and the electrolyte, generating current and outputting electrical energy. Since fuel cells generate water and release a large amount of heat during operation, it is necessary to discharge the generated water in a timely manner and dissipate the heat of the fuel cell at the same time. Otherwise, the performance and life of the fuel cell will be seriously affected.

[0003] The function of the bipolar plate of a fuel cell is to provide reaction media for the electrochemical reaction, such as hydrogen and air, to dissipate heat from the fuel cell through circulating coolant, and to discharge the water generated during the reaction. Therefore, the flow field structure design of the fuel plate is crucial. On the one hand, the structural design of the plate is related to the supply of reactants, the discharge of products and heat in the fuel cell, and directly affects the performance and reliability of the fuel cell; on the other hand, the structural design of the plate directly determines the difficulty of processing and forming the plate and the manufacturing cost. Therefore, it is necessary to conduct corresponding research on the structural design of the plate of the fuel cell.

[0004] A Chinese patent (publication number CN1287477C) provides a bipolar plate whose flow field length is three to eight times longer than the square root of the area of ​​the bipolar plate. In the invention, the extension of the flow field length is achieved by a bent multi-channel serpentine structure. In the bent area, the local pressure loss of the gas increases, the pressure drop is uneven, and at the bend, due to the rapid change of the fluid space, liquid water is not easy to discharge.

[0005] A Chinese patent (publication number CN103636041B) discloses a multi-channel serpentine flow field structure, and a plate structure in which the gas flow channel cross-sectional area decreases from the upstream of the gas inflow to the downstream of the gas outflow. In this invention, although the gas flow channel cross-sectional area is reduced to increase the gas flow rate and thus improve the drainage capacity, it poses a huge challenge to the plate forming process, increasing the difficulty and cost of manufacturing the plate.

[0006] The Chinese patent (publication number CN102017253B) discloses a multi-channel serpentine structure plate with a gradually decreasing cross-section. From the direction of fluid inflow to the direction of fluid outflow, the groove-shaped reaction gas flow channel is set to be curved or a mixture of straight and folded parts, with multiple 90° bends, and the cross-sectional areas of the flow channels in different areas are set to be different. In this invention, in the area where the flow channel bends upward, the liquid water generated in the battery is not easy to discharge due to the obstruction of the flow channel wall and the effect of gravity.

[0007] The electrode plate of the above invention constructs the flow channel by adopting a gradually changing flow channel cross-sectional area or a curved serpentine flow field structure, but it also brings problems such as difficulty in electrode plate manufacturing and increased cost. Moreover, an inappropriate flow channel configuration will have the opposite effect and form an obstacle to drainage.

[0008] The design of various structural parameters of the plate is crucial. The existing bipolar plate design has not formed a systematic design, has not comprehensively considered the various constraints of the fuel cell plate, cannot grasp the key influencing factors, has low development efficiency, and cannot achieve the expected results.

[0009] There are various structural forms of existing electrode plates. A common method is to increase the gas flow rate in the flow field by changing the cross-sectional area of ​​the flow field. Due to the limitations of the electrode forming process and manufacturing cost, the cross-sectional area of ​​the flow field changes slightly, the gas flow rate is not significantly increased, and the electrode manufacturing is difficult and costly. Another method is to use a serpentine flow field and bend the flow channel to increase the flow channel length. Because the flow channel has multiple corners, the local pressure drop of the fluid increases, and the pressure drop of the bipolar plate increases significantly, which is not conducive to the matching integration of the fuel cell system. In addition, at the corners of the flow channel, liquid water is not easy to discharge, resulting in battery flooding and a sharp decline in battery performance. Summary of the invention

[0010] In view of the above problems, the present invention discloses a method for designing a fuel cell plate structure, comprising:

[0011] Determine the relationship between plate structural parameters and fluid flow rate;

[0012] Conducting preliminary design of the structural parameters;

[0013] determining a flow rate of a fluid flowing through the plate;

[0014] determining a flow area of ​​the fluid;

[0015] determining a flow rate of the fluid;

[0016] It is determined whether the flow velocity meets the set threshold; if so, the flow field design of the electrode plate is reasonable; if not, the structural parameters of the electrode plate are redesigned.

[0017] Furthermore, the structural parameters include: the angle θ between the flow field and the horizontal direction, the flow field length a, the flow field width b, the flow field period P, the groove width w and the flow field depth d;

[0018] Among them, the structural parameters meet the following conditions:

[0019] a / b ≥ 1; or

[0020] P / w ≥ 2; or

[0021] P / d ≥ 2.5; or

[0022] a ≥ square root of total plate area; or

[0023] a·P / (w·d·cosθ)≥300.

[0024] Furthermore, the specific steps of performing preliminary design on the structural parameters are as follows:

[0025] Set the flow field period P0, groove width w0, and flow field depth d0;

[0026] Set the angle θ0 between the flow field and the horizontal direction;

[0027] Set the flow field length a0 in the active area and the flow field width b0 in the active area.

[0028] Furthermore, the flow rate of the fluid is determined by the following formula:

[0029]

[0030] Where Q is the flow rate of the fluid; λ is the stoichiometric ratio of the oxidant or fuel; j is the current density of the fuel cell; c is the concentration of the oxidant or fuel; z is the compressibility factor of the gas; n is the number of moles of electrons transferred per mole of substance undergoing electrochemical reaction; F is the Faraday constant; V m is the molar volume of the gas.

[0031] Furthermore, the flow area of ​​the fluid is determined by the following formula:

[0032]

[0033] Where A is the flow area of ​​the fluid.

[0034] Furthermore, the flow rate of the fluid is determined by the following formula:

[0035]

[0036] Where v is the flow velocity of the fluid.

[0037] The present invention also discloses a fuel cell plate prepared by the above-mentioned fuel cell plate structure design method, comprising: a gas flow field, an oxidant inlet, an oxidant outlet, a coolant inlet, a coolant outlet, a fuel outlet, a fuel inlet and a cooling water flow field;

[0038] The gas flow field is arranged on one side of the fuel cell plate;

[0039] The cooling water flow field is arranged on the other side of the fuel cell plate;

[0040] The oxidant inlet, coolant inlet and fuel outlet are arranged in parallel at one end of the fuel cell plate;

[0041] The oxidant outlet, coolant outlet and fuel inlet are arranged in parallel at the other end of the fuel cell plate.

[0042] Furthermore, the gas flow field includes a plurality of first protrusions and a plurality of first grooves;

[0043] The first protrusion and the first groove are arranged at intervals;

[0044] The sum of the width of the first protrusion and the width of the first groove is the flow field period P;

[0045] The depth of the first groove is d;

[0046] Among them, P / d≥2.5.

[0047] Furthermore, the cooling water flow field includes a plurality of second protrusions and a plurality of second grooves;

[0048] The second protrusion and the second groove are arranged at intervals;

[0049] The sum of the width of the second protrusion and the width of the second groove is the flow field period P;

[0050] The depth of the second groove is d;

[0051] Among them, P / d≥2.5.

[0052] Furthermore, a / b ≥ 1; or

[0053] P / w ≥ 2; or

[0054] a ≥ square root of total plate area; or

[0055] a·P / (w·d·cosθ)≥300.

[0056] The invention also discloses a fuel cell, comprising the fuel cell polar plate and membrane electrode assembly.

[0057] Compared with the prior art, the embodiments of the present invention have at least the following advantages:

[0058] 1) Extract more comprehensive design parameters, establish the relationship between the fluid flow rate and structural parameters of the fuel cell plate, comprehensively weigh the constraints of various parameters, clarify the logic of plate structure design, distinguish the primary and secondary, and guide the design and development of the plate and the comparison and optimization of different design schemes;

[0059] 2) By designing the flow channel structural parameters, the fluid flow rate in the plate flow field can be increased. On the one hand, it can reduce the manufacturing difficulty and cost of the bipolar plate. On the other hand, it can increase the fluid flow rate in the flow channel, improve the drainage capacity, improve the performance and specific power of the fuel cell, and enable the fuel cell stack to operate under low stoichiometric ratio conditions.

[0060] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0062] Figure 1 A flow chart showing a method for designing a fuel cell plate structure according to an embodiment of the present invention is shown;

[0063] Figure 2 A schematic cross-sectional view of a flow field of a fuel cell plate according to an embodiment of the present invention is shown;

[0064] Figure 3 A schematic structural diagram of a cathode plate according to an embodiment of the present invention is shown;

[0065] Figure 4 A schematic structural diagram of an anode plate according to an embodiment of the present invention is shown;

[0066] Figure 5 A schematic cross-sectional view of a fuel cell according to an embodiment of the present invention is shown;

[0067] Figure 6 A flow rate comparison schematic diagram according to an embodiment of the present invention is shown;

[0068] Figure 7 A performance comparison diagram according to an embodiment of the present invention is shown.

[0069] Reference numerals: 1, gas flow field; 10, air flow field; 11, first protrusion; 12, first groove; 100, cathode plate; 101, first oxidant inlet; 102, first oxidant outlet; 103, first coolant inlet; 104, first coolant outlet; 105, first fuel outlet; 106, first fuel inlet; 107, first cooling flow field;

[0070] 2. Cooling water flow field; 20. Hydrogen flow field; 21. Second protrusion; 22. Second groove; 200. Anode plate; 201. Second oxidant inlet; 202. Second oxidant outlet; 203. Second coolant inlet; 204. Second coolant outlet; 205. Second fuel outlet; 206. Second fuel inlet; 207. Second cooling flow field;

[0071] 300, membrane electrode assembly; 301, cathode side; 302, anode side;

[0072] 400. Cooling flow field. DETAILED DESCRIPTION

[0073] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0074] Figure 1 FIG. 1 is a flow chart showing a method for designing a fuel cell plate structure according to an embodiment of the present invention. Figure 1 As shown, a fuel cell plate structure design method proposed by the present invention comprises the following steps:

[0075] Step S1: determining the relationship between the plate structure parameters and the fluid flow rate;

[0076] Step S2: Preliminary design of the structural parameters;

[0077] Step S3: determining the flow rate of the fluid flowing through the electrode plate;

[0078] Step S4: determining the flow area of ​​the fluid;

[0079] Step S5: determining the flow rate of the fluid;

[0080] Step S6: determine whether the flow rate meets the set threshold; if so, the flow field design of the electrode plate is reasonable; if not, redesign the structural parameters of the electrode plate (ie, return to step S2).

[0081] Among them, the relationship between the plate structure parameters and the fluid flow rate is:

[0082]

[0083] v is the fluid velocity in the flow field;

[0084] a is the flow field length of the discontinuous flow field active area, or the path length of the fluid flow in the continuous flow field active area;

[0085] b is the flow field width of the discontinuous flow field active area, or the channel width of the fluid flowing in the same direction in the continuous flow field active area;

[0086] w is the groove width;

[0087] d is the flow field depth;

[0088] P is the sum of the width of the protrusion and the width of the groove, that is, the flow field period;

[0089] θ is the angle between the flow field and the horizontal direction, 0°≤θ<90°.

[0090] According to the logical relationship between the plate structure parameters: the flow velocity v can be changed by changing the flow field length a, flow field period P, flow field width w, flow field depth d and the angle θ between the flow field and the horizontal direction in the active area.

[0091] The fluid flow rate in the flow field is proportional to the flow field period P and inversely proportional to the flow field depth. Therefore, the flow field period P can be increased or the flow field depth d can be reduced to increase the fluid flow rate and enhance the drainage capacity, thereby reducing the mass transfer polarization of the fuel cell stack and increasing the output voltage of the fuel cell stack. At the same time, it can enable the fuel cell stack to adapt to the operating conditions of low stoichiometric ratio and reduce the auxiliary power consumption of the system.

[0092] In some embodiments, the structural parameters include: the angle θ between the flow field and the horizontal direction, the flow field length a, the flow field width b, the flow field period P, the groove width w and the flow field depth d;

[0093] Among them, the structural parameters meet the following conditions:

[0094] a / b ≥ 1; or

[0095] P / w ≥ 2; or

[0096] P / d ≥ 2.5; or

[0097] a ≥ square root of total plate area; or

[0098] a·P / (w·d·cosθ)≥300.

[0099] After theoretical research and a lot of practice, the relationship between the above structural parameters was obtained. When the structural parameters meet the above relationship, the fluid flow rate in the fuel cell plate can reach a threshold value, achieving the purpose of rapid drainage.

[0100] In some embodiments, the specific steps of performing preliminary design of the structural parameters are as follows:

[0101] According to the balance between the flow field forming process capability and the manufacturing difficulty, and the balance between the flow field performance and the manufacturing cost, the flow field period P0, the groove width w0, and the flow field depth d0 are set; for example, the flow field structure parameters of the cathode plate 100 and the anode plate 200 are designed to be the same, the flow field period P0 = 2.0 mm, the groove width w0 = 1.0 mm, and the flow field depth d0 = 0.5 mm;

[0102] According to the interface design requirements of the flow field, the angle θ0 between the flow field and the horizontal direction is set; illustratively, the angle θ0 between the flow field and the horizontal direction is 0°;

[0103] According to the output power requirement of the fuel cell, the flow field length a0 in the active area and the flow field width b0 in the active area are set; illustratively, the flow field length a0 = 240 mm and the flow field width b0 = 100 mm.

[0104] In some embodiments, according to Faraday's law, the current density is proportional to the transferred charge and the reactant consumption per unit area, and the flow rate of the fluid is determined by the following formula:

[0105]

[0106] Where Q is the flow rate of the fluid; λ is the stoichiometric ratio of the oxidant or fuel; j is the current density of the fuel cell; c is the concentration of the oxidant or fuel; z is the compressibility factor of the gas; n is the number of moles of electrons transferred per mole of substance undergoing electrochemical reaction; F is the Faraday constant; V m is the molar volume of the gas.

[0107] According to the preliminary plate design of S2, the method described in S3 was adopted, and λ=2, z=1, c=21% were taken to calculate the air flow rate under different current densities as shown in Table 1, and λ=1.5, z=1, c=1 were taken to calculate the hydrogen flow rate under different current densities as shown in Table 1.

[0108] Table 1 Flow rate at different current densities

[0109]

[0110] In some embodiments, the area of ​​fluid flow is calculated by the product of the cross-sectional area of ​​the grooves of the flow field and the number of grooves, and the flow area of ​​the fluid is determined by the following formula:

[0111]

[0112] Where A is the flow area of ​​the fluid.

[0113] The cross-sectional area of ​​a single flow channel is calculated by the product of the groove width and the flow field depth w·d, and the ratio of the flow field width to the flow field period is calculated by To calculate the number of flow channels.

[0114] According to the preliminary plate design of S2, the fluid flow area A = 25mm is calculated using the method described in S4. 2 .

[0115] In some embodiments, the flow rate of the fluid is calculated by the ratio of the flow rate to the fluid flow area, and the flow rate of the fluid is determined by the following formula:

[0116]

[0117] Where v is the flow velocity of the fluid.

[0118] Based on the air flow rate, hydrogen flow rate and the above formula at different current densities, the flow rate of the fluid is calculated. The specific calculation results are shown in Table 2.

[0119] Table 2 Flow rate of fluids at different current densities

[0120]

[0121]

[0122] For the results calculated by the above method, if the requirements of air flow rate ≥ 0.2 m / s and hydrogen flow rate ≥ 0.1 m / s are met, the flow field design parameters are reasonable and the detailed design of the flow field structure can be carried out.

[0123] The present invention provides a method for designing a fuel cell plate structure. By establishing a relationship between a structural parameter of a fuel cell and a fluid flow rate, a method is provided for the structural design of a fuel cell plate. By the method, key structural parameters that affect the flow rate in a fuel cell plate are proposed, and the flow rate of the fluid can be changed by designing the structural parameters, that is, by designing the ratio of the flow field length and width of an active area of ​​the plate; or the ratio of the plate flow field period to the groove width of a gas flow channel; or the ratio of the plate flow field period to the flow channel depth. Without increasing the manufacturing difficulty and cost of a bipolar plate, the gas flow rate of the flow field can be significantly improved, the drainage power can be enhanced, the battery can be prevented from being flooded, the mass transfer polarization of the battery can be reduced, the battery performance can be improved, and the battery can be adapted to low stoichiometric ratio operating conditions, thereby improving the power density of a battery stack.

[0124] like Figure 2 As shown, the present invention also discloses a fuel cell plate prepared by the above-mentioned fuel cell plate structure design method, comprising: a gas flow field 1, an oxidant inlet, an oxidant outlet, a coolant inlet, a coolant outlet, a fuel outlet, a fuel inlet and a cooling water flow field 2;

[0125] The gas flow field 1 is arranged on one side of the fuel cell plate;

[0126] The cooling water flow field 2 is arranged on the other side of the fuel cell plate;

[0127] The oxidant inlet, coolant inlet and fuel outlet are arranged in parallel at one end of the fuel cell plate;

[0128] The oxidant outlet, coolant outlet and fuel inlet are arranged in parallel at the other end of the fuel cell plate.

[0129] In some embodiments, the gas flow field 1 includes a plurality of first protrusions 11 and a plurality of first grooves 12;

[0130] The first protrusion 11 and the first groove 12 are arranged at intervals;

[0131] The sum of the width of the first protrusion 11 and the width of the first groove 12 is the flow field period P;

[0132] The depth of the first groove 12 is d;

[0133] Among them, P / d≥2.5.

[0134] The first protrusion 11 is used to support the fuel cell plate;

[0135] The first groove 12 is used for gas circulation.

[0136] In some embodiments, the cooling water flow field 2 includes a plurality of second protrusions 21 and a plurality of second grooves 22;

[0137] The second protrusion 21 and the second groove 22 are arranged at intervals;

[0138] The sum of the width of the second protrusion 21 and the width of the second groove 22 is the flow field period P;

[0139] The depth of the second groove 22 is d;

[0140] Among them, P / d≥2.5.

[0141] The second protrusion 21 is used to support the fuel cell plate;

[0142] The second groove 22 is used for cooling water to flow.

[0143] The structural parameters of the gas flow field 1 and the cooling water flow field 2 may be the same or different.

[0144] In some embodiments, a / b ≥ 1; or

[0145] P / w ≥ 2; or

[0146] a ≥ square root of total plate area; or

[0147] a·P / (w·d·cosθ)≥300.

[0148] The fuel cell plates are divided into a cathode plate 100 and an anode plate 200 .

[0149] The cathode plate 100 is used to transport air;

[0150] The anode plate 200 is used to transport hydrogen.

[0151] like Figure 3 As shown, the cathode plate 100 includes: an air flow field 10, a first oxidant inlet 101, a first oxidant outlet 102, a first coolant inlet 103, a first coolant outlet 104, a first fuel outlet 105, a first fuel inlet 106 and a first cooling flow field 107; the air flow field 10 is composed of a plurality of spaced grooves;

[0152] The air flow field 10 is arranged on one side of the cathode plate 100;

[0153] The first cooling flow field 107 is disposed on the other side of the cathode plate 100;

[0154] The first oxidant inlet 101, the first coolant inlet 103 and the first fuel outlet 105 (arranged in sequence from top to bottom) are arranged in parallel at one end of the cathode plate 100;

[0155] The first oxidant outlet 102 , the first coolant outlet 104 and the first fuel inlet 106 (arranged in sequence from bottom to top) are arranged in parallel at the other end of the cathode plate 100 .

[0156] An air flow field 10, for air circulation;

[0157] A first oxidant inlet 101 for air to flow into the fuel cell plate;

[0158] A first oxidant outlet 102 for air to flow out of the fuel cell plate;

[0159] A first coolant inlet 103, for cooling water to flow into the fuel cell plate;

[0160] A first coolant outlet 104, for cooling water to flow out of the fuel cell plate;

[0161] A first fuel outlet 105, for hydrogen to flow out of the fuel cell plate;

[0162] A first fuel inlet 106 for hydrogen to flow into the fuel cell plate;

[0163] The first cooling flow field 107 is used for cooling water to flow inside the fuel cell plate.

[0164] like Figure 4 As shown, the anode plate 200 includes: a hydrogen flow field 20, a second oxidant inlet 201, a second oxidant outlet 202, a second coolant inlet 203, a second coolant outlet 204, a second fuel outlet 205, a second fuel inlet 206 and a second cooling flow field 207; the hydrogen flow field 20 is composed of a plurality of spaced grooves;

[0165] The hydrogen flow field 20 and the second cooling flow field 207 are respectively arranged on both sides of the anode plate 200;

[0166] The second oxidant inlet 201, the second coolant inlet 203 and the second fuel outlet 205 (arranged in sequence from bottom to top) are arranged in parallel at one end of the anode plate 200;

[0167] The second oxidant outlet 202 , the second coolant outlet 204 and the second fuel inlet 206 (arranged in sequence from top to bottom) are arranged in parallel at the other end of the anode plate 200 .

[0168] A hydrogen flow field 20, used for hydrogen flow;

[0169] A second oxidant inlet 201 for air to flow into the fuel cell plate;

[0170] A second oxidant outlet 202 for air to flow out of the fuel cell plate;

[0171] A second coolant inlet 203, for cooling water to flow into the fuel cell plate;

[0172] A second coolant outlet 204 for cooling water to flow out of the fuel cell plate;

[0173] A second fuel outlet 205 for hydrogen to flow out of the fuel cell plate;

[0174] A second fuel inlet 206 for hydrogen to flow into the fuel cell plate;

[0175] The second cooling flow field 207 is used for cooling water to flow inside the fuel cell plates.

[0176] In some embodiments, the cathode plate 100 and the anode plate 200 are made of stainless steel or titanium alloy metal sheets by stamping, which have the advantages of high conductivity, corrosion resistance, and easy processing and forming. The cathode plate 100 and the anode plate 200 can also be made of conductive materials such as graphite.

[0177] In some embodiments, the first cooling flow field 107 of the cathode plate 100 and the second cooling flow field 207 of the anode plate 200 are relatively combined to form a cooling flow field 400 .

[0178] like Figure 5 As shown, the present invention also discloses a fuel cell, comprising the cathode plate 100, the anode plate 200 and the membrane electrode assembly 300 mentioned above;

[0179] The cathode plate 100, the anode plate 200, the membrane electrode assembly 300, the cathode plate 100 and the anode plate 200 are arranged in sequence;

[0180] Specifically, the first cooling flow field 107 side of the cathode plate 100 abuts against the second cooling flow field 207 of the anode plate 200 (the first oxidant inlet 101 is connected to the second oxidant inlet 201 correspondingly, the first oxidant outlet 102 is connected to the second oxidant outlet 202 correspondingly, and the inlets and outlets of other coolants and fuels are also connected to each other correspondingly, which will not be repeated), the hydrogen flow field 20 side of the anode plate 200 abuts against the anode side 302 of the membrane electrode assembly 300, the cathode side 301 of the membrane electrode assembly 300 abuts against the air flow field 10 side of the cathode plate 100, and the first cooling flow field 107 side of the cathode plate 100 abuts against the second cooling flow field 207 of the anode plate 200.

[0181] If the fuel cell plate is formed by stamping, the above design method determines the structure of the cooling flow field 400 of the plate;

[0182] The fuel cell is formed by stacking the above-mentioned fuel cell plates on both sides of a membrane electrode assembly 300, wherein the cathode plate 100 is placed on the cathode side 301 of the membrane electrode assembly 300, and the anode plate 200 is placed on the anode side 302 of the membrane electrode assembly 300.

[0183] Based on the above-mentioned fuel cell plate structure design method, a fuel cell plate was prepared and prepared into a fuel cell embodiment, and a fuel cell comparative example was also prepared at the same time. The specific data are shown in Table 3.

[0184] Table 3 Plate structure parameters of the embodiments and comparative examples

[0185]

[0186] The other structural parameters are the same: flow field length a = 240 mm, flow field width b = 100 mm, P / w = 2, and the angle between the flow field and the horizontal direction θ = 0°;

[0187] like Figure 6 As shown, the air flow rate of the fuel cell of the embodiment and the comparative example is compared, both of which take λ=2, z=1. The step S5 is used to calculate the air flow rate of the fuel cell of the embodiment and the comparative example at different current densities. The flow rate of P / d=4 is greater than the flow rate of P / d=2.4. It can be seen that with the increase of the sum of the width of the protrusion and the width of the groove P, or the decrease of the depth d of the groove, the flow rate in the flow field is significantly improved. Therefore, the liquid water in the flow field can be quickly discharged from the battery by the airflow to avoid the battery flooding phenomenon; moreover, the increase of the sum of the width of the protrusion and the width of the groove P, or the decrease of the depth d of the groove, can greatly reduce the manufacturing difficulty and cost of the plate, especially for the plate formed by stamping of metal sheets, as the width-to-depth ratio of the stamping increases, the difficulty of stamping is significantly reduced. The fuel cell performance of the two design schemes is compared below.

[0188] like Figure 7 As shown, it is a performance comparison between the fuel cell of the embodiment and the fuel cell of the comparative example. In the embodiment, as the flow velocity in the flow field increases, the liquid water in the flow field is quickly discharged, and the mass transfer polarization in the stack is reduced. The performance of the stack of the embodiment in the high electric density area is significantly higher than that of the comparative example.

[0189] Based on the above analysis, among the above comparative design schemes, the design scheme with P / d≥2.5, i.e., the present embodiment, is selected. The structural parameter of P / d=4 is better. On the one hand, compared with the comparative example P / d=2.4 design scheme, the present embodiment can significantly increase the flow rate, improve the drainage capacity, and reduce the mass transfer polarization in the high current density area; on the other hand, compared with the comparative example P / d=2.4 design scheme, the present embodiment can greatly reduce the manufacturing difficulty and cost of the electrode plate.

[0190] The fuel cell plate structure design method, fuel cell plate and fuel cell thereof proposed in the present invention extract more comprehensive design parameters, establish the relationship between the fluid flow rate and the structural parameters of the fuel cell plate, comprehensively weigh the constraint relationship of each parameter, clarify the logic of the plate structure design, distinguish the primary from the secondary, guide the design and development of the plate and the comparison and optimization of different design schemes; the fluid flow rate in the plate flow field is improved by designing the flow channel structural parameters, which can reduce the manufacturing difficulty and cost of the bipolar plate on the one hand, and increase the fluid flow rate in the flow channel on the other hand, improve the drainage capacity, improve the performance and specific power of the fuel cell, and make the fuel cell stack adapt to the operation under low stoichiometric ratio conditions.

[0191] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for designing a fuel cell plate structure, characterized in that: include: Determine the relationship between plate structural parameters and fluid flow rate; Conducting preliminary design of the structural parameters; determining a flow rate of a fluid flowing through the plate; determining a flow area of ​​the fluid; determining a flow rate of the fluid; It is determined whether the flow velocity meets the set threshold; if so, the flow field design of the electrode plate is reasonable; if not, the structural parameters of the electrode plate are redesigned.

2. The method for designing a fuel cell plate structure according to claim 1, characterized in that: The structural parameters include: the angle θ between the flow field and the horizontal direction, the flow field length a, the flow field width b, the flow field period P, the groove width w and the flow field depth d; Among them, the structural parameters meet the following conditions: a / b ≥ 1; or P / w ≥ 2; or P / d ≥ 2.5; or a ≥ square root of total plate area; or a·P / (w·d·cosθ)≥300.

3. The method for designing a fuel cell plate structure according to claim 1, characterized in that: The specific steps of carrying out preliminary design of the structural parameters are as follows: Set the flow field period P0, groove width w0, and flow field depth d0; Set the angle θ0 between the flow field and the horizontal direction; Set the flow field length a0 in the active area and the flow field width b0 in the active area.

4. The method for designing a fuel cell plate structure according to claim 1, characterized in that: The flow rate of the fluid is determined by the following formula: Where Q is the flow rate of the fluid; λ is the stoichiometric ratio of the oxidant or fuel; j is the current density of the fuel cell; C is the concentration of the oxidant or fuel; z is the compressibility factor of the gas; n is the number of moles of electrons transferred per mole of substance undergoing electrochemical reaction; F is the Faraday constant; V m is the molar volume of the gas.

5. The method for designing a fuel cell plate structure according to claim 1, characterized in that: The flow area of ​​the fluid is determined by the following formula: Where A is the flow area of ​​the fluid.

6. The method for designing a fuel cell plate structure according to claim 1, characterized in that: The flow rate of the fluid is determined by the following formula: Where v is the flow velocity of the fluid.

7. A fuel cell plate manufactured by the fuel cell plate structure design method according to any one of claims 1 to 6, characterized in that: include: A gas flow field (1), an oxidant inlet, an oxidant outlet, a coolant inlet, a coolant outlet, a fuel outlet, a fuel inlet and a cooling water flow field (2); The gas flow field (1) is arranged on one side of the fuel cell plate; The cooling water flow field (2) is arranged on the other side of the fuel cell plate; The oxidant inlet, coolant inlet and fuel outlet are arranged in parallel at one end of the fuel cell plate; The oxidant outlet, coolant outlet and fuel inlet are arranged in parallel at the other end of the fuel cell plate.

8. The fuel cell plate according to claim 7, characterized in that: The gas flow field (1) comprises a plurality of first protrusions (11) and a plurality of first grooves (12); The first protrusion (11) and the first groove (12) are arranged at intervals; The sum of the width of the first protrusion (11) and the width of the first groove (12) is the flow field period P; The depth of the first groove (12) is d; Among them, P / d≥2.

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9. The fuel cell plate according to claim 8, characterized in that: The cooling water flow field (2) comprises a plurality of second protrusions (21) and a plurality of second grooves (22); The second protrusion (21) and the second groove (22) are arranged at intervals; The sum of the width of the second protrusion (21) and the width of the second groove (22) is the flow field period P; The depth of the second groove (22) is d; Among them, P / d≥2.

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10. The fuel cell plate according to claim 7, characterized in that: a / b ≥ 1; or P / w ≥ 2; or a ≥ square root of total plate area; or a·P / (w·d·cosθ)≥300.

11. A fuel cell, characterized in that: The fuel cell plate and membrane electrode assembly (300) include any one of claims 7 to 10.

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