Electric pile of fuel cell, fuel cell and electric device

Abstract

The invention provides an electric pile of a fuel cell, the fuel cell and an electric device. The electric pile comprises an anode collector plate, a cathode collector plate and an electric pile core arranged between the anode collector plate and the cathode collector plate, the reactor core comprises a near-anode reactor core close to the anode collector plate, a middle reactor core and a near-cathode reactor core close to the cathode collector plate, which are sequentially stacked; the near-anode reactor core, the middle reactor core and the near-cathode reactor core respectively and independently comprise at least one single battery which is connected in series and arranged in a stacked manner; and the flow channel volumes of the anode flow channels and the cathode flow channels in the near-anode reactor core and the near-cathode reactor core are greater than those of the anode flow channels and the cathode flow channels in the middle reactor core. In the fuel cell stack, the cathode flow channels and the anode flow channels of the single cells in the near-anode reactor core and the near-cathode reactor core have smaller flow resistance, more heat can be generated during low-temperature cold start, internal icing is prevented, and the fuel cell can realize lossless low-temperature cold start within ideal duration.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of fuel cells, and relates to a fuel cell stack, in particular to a fuel cell stack, a fuel cell and an electric device. BACKGROUND

[0002] A proton exchange membrane fuel cell is a clean, efficient and green power supply. The fuel cell converts chemical energy into electrical energy through the reaction of hydrogen and oxygen at the anode and cathode, has high energy conversion efficiency, small working noise, no emission and many other advantages, and has great application potential in the fields of automobiles, fixed power stations, portable power generation devices, submarines and space shuttles.

[0003] However, there are still some problems to be solved in the popularization and application of fuel cells, among which the low-temperature cold start success rate and starting speed below 0℃ are the main limitations. Specifically, in an environment below 0℃, the icing inside the stack will cause the gas transmission channel of the gas diffusion layer to be blocked, resulting in mass transfer loss. Secondly, the icing will cover the electrochemical three-phase active sites in the catalyst layer, causing the reaction active area to decrease. In addition, the icing and ice melting cycle will cause permanent damage to the fuel cell membrane electrode material, leading to irreversible decay, and in severe cases, significantly reducing the performance and life of the battery.

[0004] Therefore, it is crucial to develop a suitable fuel cell stack structure to enable the fuel cell to achieve lossless low-temperature cold start within a desired time. However, the fuel cell electrocatalysis disclosed in the prior art still cannot fully optimize the low-temperature cold start performance of the fuel cell.

[0005] CN103825037A discloses a fuel cell cold start rapid heating system, which comprises a hydrogen delivery pipeline and a fuel cell stack, the hydrogen delivery pipeline delivers hydrogen into the flow channel on the anode side of the fuel cell stack, further comprises a heater, a temperature meter and a battery control system; the heater is arranged on the hydrogen delivery pipeline to heat the hydrogen; the temperature meter is arranged inside the fuel cell stack to measure the temperature of the stack; the data acquisition end of the battery control system is connected with the temperature meter, and the output end is connected with the heater, and the opening and closing of the heater is controlled according to the temperature of the stack measured by the temperature meter.

[0006] CN107154503A discloses a long-life fuel cell stack module that can be quickly cold started. The overall structure is stacked in order: front end plate, front end current collecting plate, front end composite end plate, sealing gasket, fuel cell stack, sealing gasket, rear end composite end plate, rear end current collecting plate, electric heating isolation plate and rear end plate are stacked together, and then bundled and compressed with a bundling type fixing belt with elastic stress memory capability; finally, fixed through elastic elements, fastening bolts and studs.

[0007] For example, CN115000461A discloses a cold start system and a low-temperature cold start control method for a hydrogen fuel cell stack. The core components of the cold start system include a stack, a bipolar heater, an exhaust gas turbine, and a water-cooled PTC. The stack is connected to the bipolar heater and the exhaust gas turbine, respectively, and the PTC is connected in series with the stack.

[0008] In summary, existing fuel cell stacks all have certain shortcomings, including difficulty in effectively suppressing icing within individual cells during cold starts, resulting in suboptimal low-temperature cold-start performance for practical applications. Therefore, developing and designing a novel fuel cell stack, fuel cell, and electric motor is crucial. Summary of the Invention

[0009] To address the shortcomings of existing technologies, the present invention aims to provide a fuel cell stack, a fuel cell, and an electric device. In the stack, the cathode and anode flow channels of the individual cells in the near-anode and near-cathode cores have lower flow resistance, which can generate more heat during low-temperature cold starts and prevent internal icing. Therefore, the stack can achieve good start-up at low temperatures, and the fuel cell containing the stack can achieve non-destructive low-temperature cold starts within an ideal time.

[0010] To achieve this objective, the present invention adopts the following technical solution:

[0011] In a first aspect, the present invention provides a fuel cell stack, the fuel cell stack including an anode current collector, a cathode current collector, and a stack core disposed between the anode current collector and the cathode current collector;

[0012] The fuel cell stack core includes a near-anode core, a middle core, and a near-cathode core stacked sequentially near the anode current collector; each of the near-anode core, middle core, and near-cathode core independently includes at least one single cell stacked in series.

[0013] The flow channels of the anode and cathode channels in the near-anode core and near-cathode core are respectively larger than the flow channels of the anode and cathode channels in the central core.

[0014] As those skilled in the art will know, compared to the single cells inside the fuel cell stack core (i.e., the single cells in the middle core), the single cells at both ends of the fuel cell stack core (i.e., the single cells in the near-anode core and the near-cathode core) have poor heat preservation and slow temperature rise because they are close to the current collectors (close to the anode current collector and the cathode current collector, respectively). During cold starts, the single cells are more prone to icing and reverse polarity, which can lead to cold start failure.

[0015] Therefore, this invention provides a novel fuel cell stack in which the flow channels of the anode and cathode in the near-anode core (close to the anode current collector) and near-cathode core (close to the cathode current collector) are larger than those in the middle of the stack core. Consequently, the cathode and anode flow channels of the individual cells in the near-anode and near-cathode cores have lower flow resistance, allowing for more hydrogen or air flow during stack shutdown and purging. This facilitates the removal of moisture from the bipolar plate channels and / or membrane electrode assembly (MEA) within the individual cells. Simultaneously, the bound water content in the proton exchange membrane of the MEA in the near-anode and near-cathode cores is lower than that in the individual cells in the middle of the stack core, resulting in higher internal resistance. Therefore, during low-temperature cold starts, the individual cells in the near-anode and near-cathode cores can generate more heat, preventing internal icing. Thus, the stack can achieve good startup at low temperatures, and the fuel cell containing this stack can achieve non-destructive low-temperature cold starts within an ideal timeframe.

[0016] Preferably, the flow channel volume of the anode flow channel of a single cell in the near-anode core and near-cathode core is larger than the flow channel volume of the anode flow channel of a single cell in the central core.

[0017] Preferably, the flow channel volume of the anode flow channel of the single cell in the near-anode core and near-cathode core.

[0018] Preferably, the flow channel volume of the cathode flow channel of a single cell in the near-anode core and near-cathode core is greater than the flow channel volume of the cathode flow channel of a single cell in the central core.

[0019] Preferably, the flow channel volume of the cathode flow channel of the single cell in the near-anode core and near-cathode core is 1.05 to 1.5 times the flow channel volume of the cathode flow channel of the single cell in the central core.

[0020] Preferably, the flow channel depth and / or cross-sectional area of ​​the anode flow channel of the single cell in the near-anode core and near-cathode core are greater than the flow channel depth and / or cross-sectional area of ​​the anode flow channel of the single cell in the central core.

[0021] Preferably, the flow channel depth and / or cross-sectional area of ​​the cathode flow channel of the single cell in the near-anode core and near-cathode core are greater than the flow channel depth and / or cross-sectional area of ​​the cathode flow channel of the single cell in the central core.

[0022] Preferably, the flow channel volume of the cooling channels in the near-anode core and near-cathode core is smaller than the flow channel volume of the cooling channels in the central core.

[0023] In this invention, the flow channel volume of the cooling channels in the near-anode core and near-cathode core is smaller than that in the central core. Therefore, compared to the central core, the near-anode core and near-cathode core have greater flow resistance and lower coolant flow rate, resulting in less heat removal. This is beneficial for maintaining the temperature of individual cells in the near-anode core and near-cathode core, suppressing internal icing of individual cells in the anode core and near-cathode core, thereby improving the low-temperature cold start performance of the fuel cell stack and facilitating the non-destructive low-temperature cold start of the fuel cell containing the stack within an ideal timeframe.

[0024] Preferably, the flow channel volume of the cooling channel of the single cell in the near-anode core and near-cathode core is smaller than the flow channel volume of the cooling channel of the single cell in the central core.

[0025] Preferably, the flow channel volume of the cooling channel of the single cell in the near-anode core and near-cathode core is 0.6 to 0.95 times that of the cooling channel volume of the single cell in the central core.

[0026] Preferably, the channel depth and / or cross-sectional area of ​​the cooling channels for individual cells in the near-anode core and near-cathode core are smaller than the channel depth and / or cross-sectional area of ​​the cooling channels for individual cells in the central core.

[0027] Preferably, in the near-anode core, the middle core, and the near-cathode core, the components of a single cell all include a bipolar plate and a membrane electrode.

[0028] The reverse polarity resistance of the membrane electrodes in the single cells of the near-anode core and near-cathode core is greater than that of the membrane electrodes in the single cells of the central core.

[0029] In the fuel cell stack provided by this invention, the membrane electrode in the single cell in the near-anode core and near-cathode core has anti-reverse polarity performance, thereby allowing the single cell to be in a state of voltage below 0V for a short time during low-temperature cold start, thereby further improving the low-temperature cold start performance of the fuel cell stack.

[0030] Preferably, in the near-anode core and near-cathode core, the membrane electrode in the single cell contains anti-reverse polarity material; in the middle core, the membrane electrode in the single cell does not contain anti-reverse polarity material.

[0031] Preferably, the anti-reverse polarity material includes any one or a combination of at least two of IrO2, RuO2, NiO, or CoO.

[0032] Preferably, based on the mass fraction of the membrane electrode, the mass fraction of the anti-reverse electrode material in the membrane electrode is 0.1% to 10% of the amount of the anti-reverse electrode material as the anode Pt / C catalyst.

[0033] Preferably, in the near-anode core and the near-cathode core, the number of individual cells is 1 to 5, respectively.

[0034] Preferably, the number of individual cells in the fuel cell stack core is 10 to 700.

[0035] Preferably, the fuel cell stack further includes an anode end plate disposed on the side of the anode current collector away from the fuel cell stack core, and a cathode end plate disposed on the side of the cathode current collector away from the fuel cell stack core.

[0036] In a second aspect, the present invention provides a fuel cell comprising the stack described in the first aspect.

[0037] Thirdly, the present invention provides an electric device comprising the fuel cell described in the second aspect.

[0038] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] This invention provides a novel fuel cell stack in which the flow channels of the anode and cathode in the near-anode core (close to the anode current collector) and near-cathode core (close to the cathode current collector) are larger than those in the middle of the stack core. Therefore, the cathode and anode flow channels of the individual cells in the near-anode and near-cathode cores have lower flow resistance, allowing more hydrogen or air to flow during stack shutdown and purging. This facilitates the removal of moisture from the bipolar plate channels and / or membrane electrode assembly (MEA) within the individual cells. Simultaneously, the bound water content in the proton exchange membrane of the MEA in the near-anode and near-cathode cores is lower than that in the individual cells in the middle of the stack core, resulting in higher internal resistance. Consequently, during low-temperature cold starts, the individual cells in the near-anode and near-cathode cores can generate more heat, preventing internal icing. Therefore, the stack can achieve good startup at low temperatures, and the fuel cell containing this stack can achieve non-destructive low-temperature cold starts within an ideal timeframe. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the structure of a fuel cell stack provided in one embodiment of the present invention.

[0042] Figure 2 This is a schematic diagram of the structure of a single cell in a near-anode core and a near-cathode core provided in one embodiment of the present invention.

[0043] Figure 3 This is a schematic diagram of the structure of a single cell in the central core of the present invention, provided in one embodiment of the present invention.

[0044] Figure 4 The curves show the changes in the coolant inlet temperature and coolant outlet temperature of the fuel cell stack over time in Example 1.

[0045] Figure 5 The curves show the changes in the coolant inlet temperature and coolant outlet temperature of the fuel cell stack over time in Example 2.

[0046] Wherein, 1-cathode end plate; 2-cathode current collector plate; 3-pile core; 4-anode current collector plate; 5-anode end plate; 3-1-first anode flow channel; 3-2-first cooling flow channel; 3-3-first cathode flow channel; 3-4-first membrane electrode; 3-5-second anode flow channel; 3-6-second cooling flow channel; 3-7-second cathode flow channel; 3-8-second membrane electrode. Detailed Implementation

[0047] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0048] The "range" disclosed in this invention can be defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of the specific range. This type of range definition can include or exclude endpoints; any endpoint can be independently included or excluded, and they can be arbitrarily combined, meaning any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for specific parameters, it is understood that ranges of 60~110 and 80~120 are also expected. Furthermore, if minimum range values ​​1 and 2 are listed, and maximum range values ​​3, 4, and 5 are also listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this invention, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0" and "5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is described as an integer ≥2, it is equivalent to listing integers such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. For instance, when a parameter is described as an integer selected from "2~10", it is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0049] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions.

[0050] The term "embodiment" as used in this invention means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this invention can be combined with other embodiments.

[0051] In this invention, open-ended technical features or solutions described using terms such as "comprising" do not exclude additional members beyond those listed unless otherwise specified. They can be considered as providing both closed-ended features or solutions comprised of the listed members and open-ended features or solutions that include additional members beyond the listed members. For example, A includes a1, a2, and a3. Unless otherwise specified, it may also include other members or exclude additional members. This can be considered as providing both technical features or solutions where "A is composed of a1, a2, and a3" or "A is selected from a1, a2, and a3," and technical features or solutions where "A includes not only a1, a2, and a3, but also other members."

[0052] In this invention, unless otherwise specified, the features or solutions corresponding to "and / or" include any one of two or more of the related listed items, as well as any and all combinations of the related listed items. These arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "A and / or B" represents a group consisting of A, B, and "a combination of A and B". "Containing A and / or B" can mean "containing A, containing B, and containing A and B", or "containing A, containing B, or containing A and B", and can be appropriately understood according to the context.

[0053] In this invention, the terms "first aspect," "second aspect," "third aspect," "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," "fourth," etc., serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on the quantity.

[0054] In one implementation, such as Figure 1As shown, the present invention provides a fuel cell stack, the fuel cell stack including an anode current collector 4, a cathode current collector 2, and a fuel cell stack core 3 disposed between the anode current collector 4 and the cathode current collector 2;

[0055] The fuel cell stack core 3 includes a near-anode core, a middle core, and a near-cathode core stacked sequentially near the anode current collector 4; the near-anode core, the middle core, and the near-cathode core each independently include at least one single cell stacked in series.

[0056] The flow channels of the anode and cathode channels in the near-anode core and near-cathode core are respectively larger than the flow channels of the anode and cathode channels in the central core.

[0057] As those skilled in the art will know, compared to the single cells inside the fuel cell stack core 3 (i.e., the single cells in the middle core), the single cells at both ends of the fuel cell stack core 3 (i.e., the single cells in the near-anode core and the near-cathode core) have poor heat preservation and slow temperature rise because they are close to the current collectors (close to the anode current collector 4 and the cathode current collector 2, respectively). During cold start, the single cells are more prone to icing and reverse polarity, which leads to cold start failure.

[0058] Therefore, this invention provides a novel fuel cell stack in which the flow channels of the anode and cathode in the near-anode core (close to the anode current collector 4) and the near-cathode core (close to the cathode current collector 2) are larger than those in the anode and cathode flow channels located in the middle of the stack core 3, respectively. Thus, the cathode and anode flow channels of the individual cells in the near-anode and near-cathode cores have lower flow resistance, allowing more hydrogen or air to flow during stack shutdown and purging. This facilitates the removal of moisture from the bipolar plate flow channels and / or membrane electrode assembly (MEA) within the individual cells. Simultaneously, the bound water content in the proton exchange membrane of the MEA in the near-anode and near-cathode cores is lower than that in the individual cells in the middle of the stack core 3, resulting in higher internal resistance. Consequently, during low-temperature cold starts, the individual cells in the near-anode and near-cathode cores can generate more heat, preventing internal icing. Therefore, the stack can achieve good startup at low temperatures, and the fuel cell containing this stack can achieve non-destructive low-temperature cold starts within an ideal timeframe.

[0059] In some implementations, such as Figure 2 and Figure 3 As shown, the flow channel volume of the anode flow channel (first anode flow channel 3-1) of the single cell in the near-anode core and near-cathode core is greater than the flow channel volume of the anode flow channel (second anode flow channel 3-5) of the single cell in the middle core.

[0060] In some embodiments, the flow channel volume of the anode flow channel (first anode flow channel 3-1) of the single cell in the near-anode core and near-cathode core is 1.05 to 1.5 times the flow channel volume of the anode flow channel (second anode flow channel 3-5) of the single cell in the middle core. For example, it can be 1.05 times, 1.10 times, 1.15 times, 1.20 times, 1.25 times, 1.30 times, 1.35 times, 1.40 times, 1.45 times or 1.50 times, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0061] In some embodiments, the flow channel volume of the cathode flow channel (first cathode flow channel 3-3) of the single cell in the near-anode core and near-cathode core is greater than the flow channel volume of the cathode flow channel (second cathode flow channel 3-7) of the single cell in the middle core.

[0062] In some embodiments, the flow volume of the cathode flow channel (first cathode flow channel 3-3) of the single cell in the near-anode core and near-cathode core is 1.05 to 1.5 times the flow volume of the cathode flow channel (second cathode flow channel 3-7) of the single cell in the middle core. For example, it can be 1.05 times, 1.10 times, 1.15 times, 1.20 times, 1.25 times, 1.30 times, 1.35 times, 1.40 times, 1.45 times or 1.50 times, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0063] In some embodiments, the channel depth and / or cross-sectional area of ​​the anode channel (first anode channel 3-1) of the single cell in the near-anode core and near-cathode core are greater than the channel depth and / or cross-sectional area of ​​the anode channel (second anode channel 3-5) of the single cell in the middle core.

[0064] In some embodiments, the channel depth and / or cross-sectional area of ​​the cathode channel (first cathode channel 3-3) of the single cell in the near-anode core and near-cathode core are greater than the channel depth and / or cross-sectional area of ​​the cathode channel (second cathode channel 3-7) of the single cell in the middle core.

[0065] In some embodiments, the flow channel volume of the cooling channels in the near-anode core and near-cathode core is smaller than the flow channel volume of the cooling channels in the central core.

[0066] In this invention, the flow channel volume of the cooling channels in the near-anode core and near-cathode core is smaller than that in the central core. Therefore, compared to the central core, the near-anode core and near-cathode core have greater flow resistance and lower coolant flow rate, resulting in less heat removal. This is beneficial for maintaining the temperature of individual cells in the near-anode core and near-cathode core, suppressing internal icing of individual cells in the anode core and near-cathode core, thereby improving the low-temperature cold start performance of the fuel cell stack and facilitating the non-destructive low-temperature cold start of the fuel cell containing the stack within an ideal timeframe.

[0067] In some embodiments, the channel volume of the cooling channel (first cooling channel 3-2) of the single cell in the near-anode core and near-cathode core is smaller than the channel volume of the cooling channel (second cooling channel 3-6) of the single cell in the middle core.

[0068] In some embodiments, the channel volume of the cooling channel (first cooling channel 3-2) of the single cell in the near-anode core and near-cathode core is 0.6 to 0.95 times the channel volume of the cooling channel (second cooling channel 3-6) of the single cell in the middle core. For example, it can be 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90 or 0.95 times, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0069] In some embodiments, the channel depth and / or cross-sectional area of ​​the cooling channels (first cooling channels 3-2) of the single cells in the near-anode core and near-cathode core are smaller than the channel depth and / or cross-sectional area of ​​the cooling channels (second cooling channels 3-6) of the single cells in the central core.

[0070] In some embodiments, in the near-anode core, the middle core, and the near-cathode core, the components of a single cell all include a bipolar plate and a membrane electrode.

[0071] The reverse polarity resistance of the membrane electrodes (first membrane electrodes 3-4) in the single cells of the near-anode core and near-cathode core is greater than that of the membrane electrodes (second membrane electrodes 3-8) in the single cells of the middle core.

[0072] In the fuel cell stack provided by the present invention, the membrane electrode (first membrane electrode 3-4) in the single cell in the near anode core and near cathode core has anti-reverse polarity performance, thereby allowing the single cell to be in a state of voltage below 0V for a short time during low temperature cold start, thereby further improving the low temperature cold start performance of the fuel cell stack.

[0073] In some embodiments, in the near-anode core and near-cathode core, the membrane electrode (first membrane electrode 3-4) in the single cell contains anti-reverse polarity material; in the middle core, the membrane electrode (second membrane electrode 3-8) in the single cell does not contain anti-reverse polarity material.

[0074] In some embodiments, the anti-reverse polarity material includes any one or a combination of at least two of IrO2, RuO2, NiO or CoO. Typical but non-limiting combinations include combinations of IrO2 and RuO2, combinations of RuO2 and NiO, or combinations of RuO2, NiO and CoO.

[0075] In some embodiments, the mass fraction of the anti-reverse electrode in the membrane electrode is 0.1% to 10% of the anode Pt / C catalyst, with the mass fraction of the membrane electrode being 100%.

[0076] In some embodiments, the number of individual cells in the near-anode core and the near-cathode core is independently 1 to 5, for example, 1, 2, 3, 4 or 5 cells.

[0077] In some embodiments, the number of individual cells in the fuel cell stack core 3 is 10 to 700, for example, 10, 20, 40, 80, 100, 150, 200, 250, 300, 300, 350, 400, 450, 500, 550, 600, 650, or 700 cells, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0078] In some embodiments, the fuel cell stack further includes an anode end plate 5 disposed on the side of the anode current collector 4 away from the fuel cell stack core 3, and a cathode end plate 1 disposed on the side of the cathode current collector 2 away from the fuel cell stack core 3.

[0079] In another embodiment, the present invention provides a fuel cell comprising the stack described in the first aspect.

[0080] In another embodiment, the present invention provides an electric device comprising the fuel cell described in the second aspect.

[0081] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0082] Example 1

[0083] This embodiment provides a fuel cell stack, which includes an anode end plate 5 and a cathode end plate 1, an anode current collector 4 and a cathode current collector 2 disposed between the anode end plate 5 and the cathode end plate 1, and a stack core 3 (including 50 single cells) disposed between the anode current collector 4 and the cathode current collector 2.

[0084] The fuel cell stack core 3 includes a near-anode core, a middle core, and a near-cathode core stacked sequentially near the anode current collector 4; the near-anode core includes one single cell stacked in series, the middle core includes 48 single cells stacked in series, and the near-cathode core includes one single cell stacked in series.

[0085] The flow channel volume of the anode flow channel (first anode flow channel 3-1) of the single cell in the near-anode core and near-cathode core is 1.1 times the flow channel volume of the anode flow channel (second anode flow channel 3-5) of the single cell in the middle core. That is, the cross-sectional area of ​​the flow channel of the anode flow channel (first anode flow channel 3-1) of the single cell in the near-anode core and near-cathode core is 1.1 times the cross-sectional area of ​​the flow channel of the anode flow channel (second anode flow channel 3-5) of the single cell in the middle core.

[0086] The flow channel volume of the cathode flow channel (first cathode flow channel 3-3) of the single cell in the near-anode core and near-cathode core is 1.1 times the flow channel volume of the cathode flow channel (second cathode flow channel 3-7) of the single cell in the middle core. That is, the cross-sectional area of ​​the cathode flow channel (first cathode flow channel 3-3) of the single cell in the near-anode core and near-cathode core is 1.1 times the cross-sectional area of ​​the cathode flow channel (second cathode flow channel 3-7) of the single cell in the middle core.

[0087] The flow channel volume of the cooling channel (first cooling channel 3-2) of the single cell in the near-anode core and near-cathode core is 0.9 times the flow channel volume of the cooling channel (second cooling channel 3-6) of the single cell in the middle core. That is, the cross-sectional area of ​​the cooling channel (first cooling channel 3-2) of the single cell in the near-anode core and near-cathode core is 0.9 times the cross-sectional area of ​​the cooling channel (second cooling channel 3-6) of the single cell in the middle core.

[0088] In the near-anode core, middle core, and near-cathode core, each single cell component includes a bipolar plate and a membrane electrode; in the near-anode core and near-cathode core, the membrane electrode (first membrane electrode 3-4) in the single cell contains anti-reverse polarity material; in the middle core, the membrane electrode (second membrane electrode 3-8) in the single cell does not contain anti-reverse polarity material.

[0089] Example 2

[0090] This embodiment provides a fuel cell stack, which includes an anode end plate 5 and a cathode end plate 1, an anode current collector 4 and a cathode current collector 2 disposed between the anode end plate 5 and the cathode end plate 1, and a stack core 3 (including 50 single cells) disposed between the anode current collector 4 and the cathode current collector 2.

[0091] The fuel cell stack core 3 includes a near-anode core, a middle core, and a near-cathode core stacked sequentially near the anode current collector 4; the near-anode core includes three single cells connected in series and stacked, the middle core includes 44 single cells connected in series and stacked, and the near-cathode core includes three single cells connected in series and stacked.

[0092] The flow channel volume of the anode flow channel (first anode flow channel 3-1) of the single cell in the near-anode core and near-cathode core is 1.2 times the flow channel volume of the anode flow channel (second anode flow channel 3-5) of the single cell in the middle core. That is, the flow channel depth of the anode flow channel (first anode flow channel 3-1) of the single cell in the near-anode core and near-cathode core is 1.2 times the flow channel depth of the anode flow channel (second anode flow channel 3-5) of the single cell in the middle core.

[0093] The flow channel volume of the cathode flow channel (first cathode flow channel 3-3) of the single cell in the near-anode core and near-cathode core is 1.2 times the flow channel volume of the cathode flow channel (second cathode flow channel 3-7) of the single cell in the middle core. That is, the flow channel depth of the cathode flow channel (first cathode flow channel 3-3) of the single cell in the near-anode core and near-cathode core is 1.2 times the flow channel depth of the cathode flow channel (second cathode flow channel 3-7) of the single cell in the middle core.

[0094] The flow channel volume of the cooling channel (first cooling channel 3-2) of the single cell in the near-anode core and near-cathode core is 0.9 times the flow channel volume of the cooling channel (second cooling channel 3-6) of the single cell in the middle core. That is, the flow channel depth of the cooling channel (first cooling channel 3-2) of the single cell in the near-anode core and near-cathode core is 0.9 times the flow channel depth of the cooling channel (second cooling channel 3-6) of the single cell in the middle core.

[0095] In the near-anode core, middle core, and near-cathode core, each single cell component includes a bipolar plate and a membrane electrode; in the near-anode core and near-cathode core, the membrane electrode (first membrane electrode 3-4) in the single cell contains anti-reverse polarity material; in the middle core, the membrane electrode (second membrane electrode 3-8) in the single cell does not contain anti-reverse polarity material.

[0096] Example 3

[0097] This embodiment provides a fuel cell stack, which includes an anode end plate 5 and a cathode end plate 1, an anode current collector 4 and a cathode current collector 2 disposed between the anode end plate 5 and the cathode end plate 1, and a stack core 3 (including 20 single cells) disposed between the anode current collector 4 and the cathode current collector 2.

[0098] The fuel cell stack core 3 includes a near-anode core, a middle core, and a near-cathode core stacked sequentially near the anode current collector 4; the near-anode core includes one single cell stacked in series, the middle core includes 18 single cells stacked in series, and the near-cathode core includes one single cell stacked in series.

[0099] The flow channel volume of the anode flow channel (first anode flow channel 3-1) of the single cell in the near-anode core and near-cathode core is 1.05 times the flow channel volume of the anode flow channel (second anode flow channel 3-5) of the single cell in the middle core. That is, the flow channel depth of the anode flow channel (first anode flow channel 3-1) of the single cell in the near-anode core and near-cathode core is 1.05 times the flow channel depth of the anode flow channel (second anode flow channel 3-5) of the single cell in the middle core.

[0100] The flow volume of the cathode flow channel (first cathode flow channel 3-3) of the single cell in the near-anode core and near-cathode core is 1.05 times the flow volume of the cathode flow channel (second cathode flow channel 3-7) of the single cell in the middle core. That is, the flow depth of the cathode flow channel (first cathode flow channel 3-3) of the single cell in the near-anode core and near-cathode core is 1.05 times the flow depth of the cathode flow channel (second cathode flow channel 3-7) of the single cell in the middle core.

[0101] The flow channel volume of the cooling channel (first cooling channel 3-2) of the single cell in the near-anode core and near-cathode core is 0.95 times the flow channel volume of the cooling channel (second cooling channel 3-6) of the single cell in the middle core, that is: the flow channel depth of the cooling channel (first cooling channel 3-2) of the single cell in the near-anode core and near-cathode core is 0.90 times the flow channel depth of the cooling channel (second cooling channel 3-6) of the single cell in the middle core;

[0102] In the near-anode core, middle core, and near-cathode core, each single cell component includes a bipolar plate and a membrane electrode; in the near-anode core and near-cathode core, the membrane electrode (first membrane electrode 3-4) in the single cell contains anti-reverse polarity material; in the middle core, the membrane electrode (second membrane electrode 3-8) in the single cell does not contain anti-reverse polarity material.

[0103] Example 4

[0104] This embodiment provides a fuel cell stack, which includes an anode end plate 5 and a cathode end plate 1, an anode current collector 4 and a cathode current collector 2 disposed between the anode end plate 5 and the cathode end plate 1, and a stack core 3 (including 700 single cells) disposed between the anode current collector 4 and the cathode current collector 2.

[0105] The fuel cell stack core 3 includes a near-anode core, a middle core, and a near-cathode core stacked sequentially near the anode current collector 4; the near-anode core includes 5 single cells connected in series and stacked, the middle core includes 690 single cells connected in series and stacked, and the near-cathode core includes 5 single cells connected in series and stacked.

[0106] The flow channel volume of the anode flow channel (first anode flow channel 3-1) of the single cell in the near-anode core and near-cathode core is 1.5 times the flow channel volume of the anode flow channel (second anode flow channel 3-5) of the single cell in the middle core. That is, the cross-sectional area of ​​the flow channel of the anode flow channel (first anode flow channel 3-1) of the single cell in the near-anode core and near-cathode core is 1.5 times the cross-sectional area of ​​the flow channel of the anode flow channel (second anode flow channel 3-5) of the single cell in the middle core.

[0107] The flow channel volume of the cathode flow channel (first cathode flow channel 3-3) of the single cell in the near-anode core and near-cathode core is 1.5 times the flow channel volume of the cathode flow channel (second cathode flow channel 3-7) of the single cell in the middle core. That is, the cross-sectional area of ​​the cathode flow channel (first cathode flow channel 3-3) of the single cell in the near-anode core and near-cathode core is 1.5 times the cross-sectional area of ​​the cathode flow channel (second cathode flow channel 3-7) of the single cell in the middle core.

[0108] The flow channel volume of the cooling channel (first cooling channel 3-2) of the single cell in the near-anode core and near-cathode core is 0.6 times the flow channel volume of the cooling channel (second cooling channel 3-6) of the single cell in the middle core. That is, the cross-sectional area of ​​the cooling channel (first cooling channel 3-2) of the single cell in the near-anode core and near-cathode core is 0.6 times the cross-sectional area of ​​the cooling channel (second cooling channel 3-6) of the single cell in the middle core.

[0109] In the near-anode core, middle core, and near-cathode core, each single cell component includes a bipolar plate and a membrane electrode; in the near-anode core and near-cathode core, the membrane electrode (first membrane electrode 3-4) in the single cell contains anti-reverse polarity material; in the middle core, the membrane electrode (second membrane electrode 3-8) in the single cell does not contain anti-reverse polarity material.

[0110] Example 5

[0111] This embodiment provides a fuel cell stack where the flow channel volume of the anode flow channel (first anode flow channel 3-1) of the single cell in the near-anode and near-cathode cores is 1.01 times the flow channel volume of the anode flow channel (second anode flow channel 3-5) of the single cell in the middle core. That is, the cross-sectional area of ​​the flow channel of the anode flow channel (first anode flow channel 3-1) of the single cell in the near-anode and near-cathode cores is 1.01 times the cross-sectional area of ​​the flow channel of the anode flow channel (second anode flow channel 3-5) of the single cell in the middle core.

[0112] Furthermore, the flow channel volume of the cathode flow channel (first cathode flow channel 3-3) of the single cell in the near-anode core and near-cathode core is 1.01 times the flow channel volume of the cathode flow channel (second cathode flow channel 3-7) of the single cell in the middle core. That is, except that the cross-sectional area of ​​the cathode flow channel (first cathode flow channel 3-3) of the single cell in the near-anode core and near-cathode core is 1.01 times the cross-sectional area of ​​the cathode flow channel (second cathode flow channel 3-7) of the single cell in the middle core, all other aspects are the same as in Example 1.

[0113] Example 6

[0114] This embodiment provides a fuel cell stack, which is the same as that in Embodiment 1, except that the flow channel volume of the cooling channel (first cooling channel 3-2) of the single cell in the near anode core and near cathode core is the same as the flow channel volume of the cooling channel (second cooling channel 3-6) of the single cell in the middle core.

[0115] Example 7

[0116] This embodiment provides a fuel cell stack, except that the flow channel volume of the cooling channel (first cooling channel 3-2) of the single cell in the near-anode core and near-cathode core is 0.99 times the flow channel volume of the cooling channel (second cooling channel 3-6) of the single cell in the middle core, that is, the cross-sectional area of ​​the cooling channel (first cooling channel 3-2) of the single cell in the near-anode core and near-cathode core is 0.99 times the cross-sectional area of ​​the cooling channel (second cooling channel 3-6) of the single cell in the middle core is the same as that in Embodiment 1.

[0117] Example 8

[0118] This embodiment provides a fuel cell stack, which is the same as in Embodiment 1 except that the membrane electrode in each cell in the near-anode core, near-cathode core and middle core does not contain anti-reverse polarity material.

[0119] Comparative Example 1

[0120] This comparative example provides a fuel cell stack, except that the flow channel volume of the anode flow channel (first anode flow channel 3-1) of the single cell in the near-anode core and near-cathode core is the same as the flow channel volume of the anode flow channel (second anode flow channel 3-5) of the single cell in the middle core. That is, the flow channel depth and flow channel cross-sectional area of ​​the anode flow channel (first anode flow channel 3-1) of the single cell in the near-anode core and near-cathode core are the same as the flow channel depth and flow channel cross-sectional area of ​​the anode flow channel (second anode flow channel 3-5) of the single cell in the middle core.

[0121] Furthermore, the flow channel volume of the cathode flow channel (first cathode flow channel 3-3) of the single cell in the near-anode core and near-cathode core is the same as the flow channel volume of the cathode flow channel (second cathode flow channel 3-7) of the single cell in the middle core. That is, the flow channel depth and flow channel cross-sectional area of ​​the cathode flow channel (first cathode flow channel 3-3) of the single cell in the near-anode core and near-cathode core are the same as the flow channel depth and flow channel cross-sectional area of ​​the cathode flow channel (second cathode flow channel 3-7) of the single cell in the middle core, and all other aspects are the same as in Example 1.

[0122] Comparative Example 2

[0123] This comparative example provides a fuel cell stack in which the flow channel volume of the anode flow channel (first anode flow channel 3-1) of the single cell in the near-anode and near-cathode cores is 0.9 times the flow channel volume of the anode flow channel (second anode flow channel 3-5) of the single cell in the middle core. That is, the cross-sectional area of ​​the flow channel of the anode flow channel (first anode flow channel 3-1) of the single cell in the near-anode and near-cathode cores is 0.9 times the cross-sectional area of ​​the flow channel of the anode flow channel (second anode flow channel 3-5) of the single cell in the middle core.

[0124] The flow channel volume of the cathode flow channel (first cathode flow channel 3-3) of the single cell in the near-anode core and near-cathode core is 0.9 times the flow channel volume of the cathode flow channel (second cathode flow channel 3-7) of the single cell in the middle core. That is, except that the cross-sectional area of ​​the cathode flow channel (first cathode flow channel 3-3) of the single cell in the near-anode core and near-cathode core is 0.9 times the cross-sectional area of ​​the cathode flow channel (second cathode flow channel 3-7) of the single cell in the middle core, all other aspects are the same as in Example 1.

[0125] The coolant inlet and outlet temperatures of the fuel cell stacks provided in the above embodiments and comparative examples were tested during operation. The curves showing the change of coolant inlet and outlet temperatures of the stack in Example 1 over time are shown below. Figure 4 As shown in the figure, the curves of the coolant inlet temperature and coolant outlet temperature of the fuel cell stack in Example 2 as a function of time are as follows: Figure 5 As shown.

[0126] Low-temperature cold start tests were conducted on fuel cells containing the stacks provided in the above embodiments and comparative examples at -5℃, -10℃ and -20℃ respectively. The test method was as follows: starting from the point where the current output by the fuel cell was greater than 0, the duration from start-up to the output voltage reaching 90% of the rated voltage was recorded, and the voltage decay rate after start-up was monitored to evaluate the cold start capability. The successful start-up time of the fuel cell was obtained as shown in Table 1.

[0127] Table 1

[0128]

[0129] From Table 1 and Figures 1-5 We can obtain:

[0130] (1) The fuel cells containing the stacks provided in Examples 1 to 4 exhibit superior low-temperature cold start performance;

[0131] (2) By comparing Example 1 and Example 5, it can be seen that in the present invention, when the flow channel volume of the anode flow channel of the single cell in the near anode core and near cathode core is 1.05 to 1.5 times that of the anode flow channel of the single cell in the middle core, and the flow channel volume of the cathode flow channel of the single cell in the near anode core and near cathode core is 1.05 to 1.5 times that of the cathode flow channel of the single cell in the middle core, the fuel cell exhibits better low-temperature cold start performance. This is because the single cells on both sides have a large gas flow rate, which can make the water content of the proton membrane of the single cells on both sides lower during the purging process, that is, the internal resistance is greater, and more heat is generated during the start-up process, which is conducive to the successful start-up.

[0132] (3) By comparing Example 1 and Example 6, it can be seen that in the present invention, when the flow volume of the cooling channel in the near anode core and near cathode core is smaller than that in the middle core, the near anode core and near cathode core have greater flow resistance and smaller flow rate of coolant compared to the middle core, and less heat is carried away. This is beneficial to achieve heat preservation of single cells in the near anode core and near cathode core, suppress internal icing of single cells in the anode core and near cathode core, thereby improving the low-temperature cold start performance of the stack and facilitating the non-destructive low-temperature cold start of the fuel cell containing the stack within the ideal time.

[0133] (4) By comparing Example 1 and Example 7, it can be seen that in the present invention, when the flow channel volume of the cooling channel of the single cell in the near anode core and near cathode core is 0.6 times to 0.95 times that of the cooling channel volume of the single cell in the middle core, the fuel cell exhibits better low-temperature cold start performance. This is because the flow rate of the single cell coolant on both sides is less, and less heat is carried away, which is beneficial to cold start.

[0134] (5) By comparing Example 1 and Example 8, it can be seen that in the present invention, when the membrane electrode in the single cell of the near anode core and near cathode core of the fuel cell provided by the present invention contains anti-reverse polarity material, it has anti-reverse polarity performance, thereby allowing the single cell to be in a state of voltage below 0V for a short time during low temperature cold start, thereby further improving the low temperature cold start performance of the fuel cell.

[0135] (6) By comparing Example 1 with Comparative Examples 1 and 2, it can be seen that the present invention provides a novel fuel cell stack. In the stack, the flow channel volumes of the anode flow channel and the cathode flow channel in the near-anode core near the anode current collector 4 and the near-cathode core near the cathode current collector 2 are respectively larger than the flow channel volumes of the anode flow channel and the cathode flow channel located in the middle of the stack core 3. Therefore, the cathode flow channel and anode flow channel of the single cell in the near-anode core and the near-cathode core have smaller flow resistance, allowing more hydrogen or air to be allowed during stack shutdown and purging. The improved flow facilitates the drainage of moisture from the bipolar plate channels and / or membrane electrode assembly within each cell. Simultaneously, it results in lower bound water content in the proton exchange membranes of the membrane electrodes in the near-anode and near-cathode cores compared to the single cells in the middle of the stack core 3, leading to greater internal resistance. Consequently, during low-temperature cold starts, the single cells in the near-anode and near-cathode cores can generate more heat, preventing internal icing. Therefore, the stack can achieve good startup at low temperatures, and the fuel cell containing the stack can achieve non-destructive low-temperature cold starts within an ideal timeframe.

[0136] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A fuel cell stack, characterized in that, The fuel cell stack includes an anode current collector, a cathode current collector, and a fuel cell stack core disposed between the anode current collector and the cathode current collector; The fuel cell stack core includes a near-anode core, a middle core, and a near-cathode core that are stacked sequentially near the anode current collector. The near-anode core, the middle core, and the near-cathode core each independently include at least one single cell stacked in series; The flow channels of the anode and cathode channels in the near-anode core and near-cathode core are respectively larger than the flow channels of the anode and cathode channels in the central core.

2. The fuel cell stack according to claim 1, characterized in that, The flow channel volume of the anode flow channel of a single cell in the near-anode core and near-cathode core is larger than the flow channel volume of the anode flow channel of a single cell in the middle core. Preferably, the flow channel volume of the anode flow channel of the single cell in the near-anode core and near-cathode core is 1.05 to 1.5 times the flow channel volume of the anode flow channel of the single cell in the central core; Preferably, the flow channel volume of the cathode flow channel of a single cell in the near-anode core and near-cathode core is larger than the flow channel volume of the cathode flow channel of a single cell in the central core. Preferably, the flow channel volume of the cathode flow channel of the single cell in the near-anode core and near-cathode core is 1.05 to 1.5 times the flow channel volume of the cathode flow channel of the single cell in the central core.

3. The fuel cell stack according to claim 2, characterized in that, The channel depth and / or cross-sectional area of ​​the anode flow channel of the single cell in the near-anode core and near-cathode core are greater than the channel depth and / or cross-sectional area of ​​the anode flow channel of the single cell in the middle core. Preferably, the flow channel depth and / or cross-sectional area of ​​the cathode flow channel of the single cell in the near-anode core and near-cathode core are greater than the flow channel depth and / or cross-sectional area of ​​the cathode flow channel of the single cell in the central core.

4. The fuel cell stack according to claim 1, characterized in that, The flow channel volume of the cooling channels in the near-anode core and near-cathode core is smaller than the flow channel volume of the cooling channels in the central core.

5. The fuel cell stack according to claim 4, characterized in that, The flow channel volume of the cooling channel of the single cell in the near-anode core and near-cathode core is smaller than the flow channel volume of the cooling channel of the single cell in the central core. Preferably, the flow channel volume of the cooling channel of the single cell in the near-anode core and near-cathode core is 0.6 to 0.95 times that of the cooling channel volume of the single cell in the central core.

6. The fuel cell stack according to claim 5, characterized in that, The channel depth and / or cross-sectional area of ​​the cooling channels for individual cells in the near-anode core and near-cathode core are smaller than the channel depth and / or cross-sectional area of ​​the cooling channels for individual cells in the central core.

7. The fuel cell stack according to claim 1, characterized in that, In the near-anode core, middle core, and near-cathode core, each single cell component includes a bipolar plate and a membrane electrode. The reverse polarity resistance of the membrane electrodes in the single cells of the near-anode core and near-cathode core is greater than that of the membrane electrodes in the single cells of the central core. Preferably, in the near-anode core and near-cathode core, the membrane electrode in the single cell contains anti-reverse polarity material; in the middle core, the membrane electrode in the single cell does not contain anti-reverse polarity material. Preferably, the anti-reverse polarity material comprises any one or a combination of at least two of IrO2, RuO2, NiO, or CoO; Preferably, the mass fraction of the anti-reverse electrode in the membrane electrode is 0.1% to 10% of the anode Pt / C catalyst, based on the mass fraction of the membrane electrode as 100%.

8. The fuel cell stack according to any one of claims 1 to 7, characterized in that, In the near-anode core and near-cathode core, the number of individual cells is independently 1 to 5. Preferably, the number of individual cells in the fuel cell stack core is 10 to 700. Preferably, the fuel cell stack further includes an anode end plate disposed on the side of the anode current collector away from the fuel cell stack core, and a cathode end plate disposed on the side of the cathode current collector away from the fuel cell stack core.

9. A fuel cell, characterized in that, The fuel cell includes the stack as described in any one of claims 1 to 8.

10. An electric device, characterized in that, The electric device includes the fuel cell of claim 9.

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