Heat exchange device and fuel cell system

Abstract

The invention discloses a heat exchange device and system based on a fuel cell. According to the scheme, the heat exchange device is provided with a first-stage heat exchange module, a combustor and a second-stage heat exchange module; the hot side input end of the first-stage heat exchange module is connected with the tail gas output end of the electric pile, the hot side output end of the first-stage heat exchange module is connected with the input end of the combustor, the output end of the combustor is connected with the hot side input end of the second-stage heat exchange module, and the cold side output end of the second-stage heat exchange module is connected with the input end of the electric pile; the primary heat exchange module is arranged between the combustor and the tail gas output end of the electric pile, so that the temperature of the electric pile tail gas entering the combustor is reduced, the temperature of the tail gas during combustion of the combustor and the temperature of the output tail gas are further reduced, the heat-resistant requirements of the combustor and the heat exchange module are reduced, and the implementation cost is reduced; a first-stage heat exchange module and a second-stage heat exchange module are designed, so that the distribution quantity of tail gas output by the combustor is reduced, and the design difficulty is reduced; the embodiment of the invention can be widely applied to the technical field of fuel cells.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a heat exchange device and a fuel cell system. Background Art

[0002] Solid Oxide Fuel Cell (SOFC) is an all-solid-state chemical power generation device that directly converts the chemical energy of hydrocarbon fuels into electrical energy. Existing SOFC systems usually use a heat exchange network to recover energy from the exhaust gas emitted by the stack. The heat exchange network burns the exhaust gas through a burner and outputs high-temperature exhaust gas to heat the fuel, air and water required by the SOFC system, thereby improving power generation efficiency and energy utilization. However, the heating requirements for fuel, air and water are different, and the design of the high-temperature exhaust gas distribution ratio of the burner in the existing heat exchange network is difficult. At the same time, the high-temperature exhaust gas output by the burner in the existing heat exchange network can reach up to 900°C, and the burner is at risk of overheating, which places high requirements on the heat resistance of the burner and heat exchange components and has high implementation costs. Summary of the invention

[0003] The main purpose of the embodiments of the present invention is to provide a heat exchange device and a fuel cell system, which can reduce the difficulty of flow distribution design and reduce the implementation cost.

[0004] To achieve the above-mentioned purpose, one aspect of an embodiment of the present invention provides a heat exchange device, which is connected to a fuel cell stack and includes a primary heat exchange module, a burner, and a secondary heat exchange module; wherein:

[0005] The hot side input end of the first-stage heat exchange module is connected to the tail gas output end of the fuel cell stack, and the hot side output end of the first-stage heat exchange module is connected to the input end of the burner;

[0006] The output end of the burner is connected to the hot side input end of the secondary heat exchange module;

[0007] The cold side output end of the secondary heat exchange module is connected to the input end of the fuel cell stack.

[0008] In some embodiments, the secondary heat exchange module includes a diversion chamber, a first heat exchanger and a second heat exchanger; wherein,

[0009] The input end of the diverter cavity is connected to the output end of the burner, the first output end of the diverter cavity is connected to the first heat exchanger, and the second output end of the diverter cavity is connected to the second heat exchanger.

[0010] In some embodiments, the secondary heat exchange module includes a third heat exchanger and a fourth heat exchanger; wherein,

[0011] The hot side input end of the third heat exchanger is connected to the output end of the burner, and the hot side output end of the third heat exchanger is connected to the hot side input end of the fourth heat exchanger.

[0012] In some embodiments, the primary heat exchange module includes an evaporator; wherein,

[0013] The hot side input end of the evaporator is connected to the tail gas output end of the fuel cell stack, the cold side input end of the evaporator is connected to liquid water, and the hot side output end of the evaporator is connected to the input end of the burner.

[0014] In some embodiments, the device further comprises a pre-reformer, and the primary heat exchange module comprises a gas heat exchanger; wherein,

[0015] The hot side input end of the gas heat exchanger is connected to the exhaust gas output end of the fuel cell stack, the cold side input end of the gas heat exchanger is connected to the output end of the pre-reformer, the cold side output end of the gas heat exchanger is connected to the input end of the fuel cell stack, and the hot side output end of the gas heat exchanger is connected to the input end of the burner.

[0016] In some embodiments, the device further comprises a mixer, and the secondary heat exchange module comprises an air heat exchanger and an evaporator; wherein,

[0017] The output end of the burner is respectively connected to the hot side input end of the air heat exchanger and the hot side input end of the evaporator;

[0018] The cold side input end of the air heat exchanger is connected to an air source, and the cold side output end of the air heat exchanger is connected to the input end of the fuel cell stack;

[0019] The cold side input end of the evaporator is connected to liquid water, and the cold side output end of the evaporator is connected to the input end of the mixer;

[0020] The mixer is used to mix fuel and high-temperature water vapor; the first input end of the mixer is connected to the fuel source, the second input end of the mixer is connected to the output end of the water evaporator, and the output end of the mixer is connected to the input end of the pre-reformer;

[0021] The pre-reformer is used to reform the fuel to obtain reformed fuel; the output end of the pre-reformer is connected to the primary heat exchange module or the secondary heat exchange module.

[0022] In some embodiments, the tail gas output end of the fuel cell system includes an anode output end and a cathode output end.

[0023] In some embodiments, the anode output end is connected to the hot side input end of the primary heat exchange module, and the cathode output end is connected to the input end of the burner.

[0024] In some embodiments, the cathode output end is connected to the hot side input end of the primary heat exchange module, and the anode output end is connected to the input end of the burner.

[0025] To achieve the above-mentioned purpose, another aspect of an embodiment of the present invention provides a fuel cell system, the system comprising a fuel cell stack and a heat exchange network; wherein:

[0026] The fuel cell stack is used to generate electricity and produce fuel cell tail gas;

[0027] The heat exchange network includes any of the devices described above, and is used to exchange heat with the fuel according to the fuel cell tail gas.

[0028] Implementation of the embodiments of the present invention includes the following beneficial effects: This embodiment provides a heat exchange device and a fuel cell system, which includes a primary heat exchange module, a burner and a secondary heat exchange module, the hot side input end of the primary heat exchange module is connected to the exhaust gas output end of the fuel cell stack, the hot side output end of the primary heat exchange module is connected to the input end of the burner, the output end of the burner is connected to the hot side input end of the secondary heat exchange module, and the cold side output end of the secondary heat exchange module is connected to the input end of the fuel cell stack; by arranging a primary heat exchange module between the burner and the exhaust gas output end of the fuel cell stack, the high temperature of the fuel cell stack exhaust gas is used as the heat source of the primary heat exchange module, and the material input to the primary heat exchange module is heated and heated, while reducing the temperature of the fuel cell stack exhaust gas entering the burner, reducing the risk of overheating of the burner, and arranging the primary heat exchange module in front of the burner, reducing the difficulty of distributing the exhaust gas output by the burner, reducing the heat resistance requirements of the burner and the heat exchange module, and reducing the implementation cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a structural block diagram of a heat exchange device provided by an embodiment of the present invention;

[0030] Figure 2 is a structural block diagram of a mixer and a pre-reformer in a heat exchange device provided in an embodiment of the present invention;

[0031] Figure 3 It is a structural block diagram of a secondary heat exchange module in a heat exchange device provided in an embodiment of the present invention;

[0032] Figure 4 is a structural block diagram of a heat exchange device provided by an embodiment of the present invention;

[0033] Figure 5 is another structural block diagram of a heat exchange device provided by an embodiment of the present invention;

[0034] Figure 6 is a structural block diagram of another secondary heat exchange module in a heat exchange device provided in an embodiment of the present invention;

[0035] Figure 7 This is a structural block diagram of a battery stack connection in a heat exchange device provided in an embodiment of the present invention;

[0036] Figure 8 It is a structural block diagram of another type of battery stack connection in a heat exchange device provided in an embodiment of the present invention;

[0037] Fig. 9 It is a structural block diagram of a fuel cell system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0038] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The step numbers in the following embodiments are only provided for the convenience of explanation and description, and the order between the steps is not limited in any way. The execution order of each step in the embodiment can be adaptively adjusted according to the understanding of those skilled in the art.

[0039] In the following description, reference is made to “some embodiments”, which describe a subset of all possible embodiments, but it will be understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0040] In the following description, the terms "first\second\third" involved are merely used to distinguish similar objects and do not represent a specific ordering of the objects. It can be understood that "first\second\third" can be interchanged with a specific order or sequence where permitted, so that the embodiments of the present invention described herein can be implemented in an order other than that illustrated or described herein.

[0041] Unless otherwise defined, all technical and scientific terms used in the embodiments of the present invention have the same meanings as those commonly understood by those skilled in the art of the present invention. The terms used in the embodiments of the present invention are only for the purpose of describing the embodiments of the present invention and are not intended to limit the present invention.

[0042] See also Figure 1 , Figure 1 A heat exchange device based on a fuel cell system provided by an embodiment of the present invention includes a primary heat exchange module, a burner, and a secondary heat exchange module; wherein:

[0043] The hot side input end of the first-stage heat exchange module is connected to the tail gas output end of the fuel cell stack, and the hot side output end of the first-stage heat exchange module is connected to the input end of the burner;

[0044] The output end of the burner is connected to the hot side input end of the secondary heat exchange module;

[0045] The cold side output end of the secondary heat exchange module is connected to the input end of the fuel cell stack.

[0046] In some embodiments, a heat exchange device is connected to a fuel cell stack, and a hot side input end of a first-level heat exchange module in the heat exchange device is connected to an exhaust gas output end of the fuel cell stack, and the exhaust gas of the fuel cell output provides a heat source for the first-level heat exchange module, heats and raises the temperature of the material input into the first-level heat exchange module, and reduces the temperature of the exhaust gas of the stack; the hot side output end of the first-level heat exchange module is connected to an input end of a burner, and the first-level heat exchange module outputs the exhaust gas of the stack after heat exchange to the burner, and the exhaust gas of the stack burns in the burner to raise the temperature of the exhaust gas; the burner outputs the exhaust gas with increased temperature to a second-level heat exchange module connected to the burner, provides a heat source for the second-level heat exchange module, and heats and raises the temperature of the material input into the second-level heat exchange module; the second-level heat exchange module heats and raises the temperature of the input material through the high-temperature exhaust gas output from the burner, and outputs the heat-exchanged and heated material to the fuel cell stack, and the fuel cell generates electricity by performing an electrochemical reaction on the heat-exchanged and heated material.

[0047] See also Figure 2 In some embodiments, a heat exchange device based on a fuel cell system provided by an embodiment of the present invention further includes a mixer and a pre-reformer; wherein,

[0048] A mixer is used to mix fuel and high-temperature steam; a first input end of the mixer is connected to a fuel source, a second input end of the mixer is connected to the high-temperature steam, and an output end of the mixer is connected to an input end of the pre-reformer;

[0049] The pre-reformer is used to reform the fuel to obtain reformed fuel; the output end of the pre-reformer is connected to the primary heat exchange module or the secondary heat exchange module.

[0050] In some embodiments, a fuel cell uses hydrocarbon fuel to generate electricity. In order to improve the power generation efficiency of the fuel cell and avoid carbon deposition inside the fuel cell, a mixer and a pre-reformer are provided in the heat exchange device. The hydrocarbon fuel of the fuel cell reacts chemically with water to convert high-carbon hydrocarbons into low-carbon substances, which are then input into the fuel cell for electrochemical reaction. In this embodiment, the input end of the mixer is respectively connected to the fuel and the high-temperature water vapor, and the high-temperature water vapor is obtained by heat exchange and temperature increase of liquid water by a primary heat exchange module or a secondary heat exchange module according to the tail gas of the fuel cell stack or the tail gas of the burner; the mixer mixes the fuel and the high-temperature water vapor and outputs them to the pre-reformer; the input end of the pre-reformer is connected to the output end of the mixer, and receives the fuel-high-temperature water vapor mixture output by the mixer. The high-temperature water vapor mixture provides suitable temperature conditions for the pre-reforming reaction of the pre-reformer. The pre-reformer outputs the reformed fuel to the connected primary heat exchange module or the secondary heat exchange module, and the reformed fuel is heat exchanged and heated by the primary heat exchange module or the secondary heat exchange module to reach the temperature required for the electrochemical reaction of the fuel cell.

[0051] See also Figure 3 In some embodiments, the present invention provides a secondary heat exchange module in a heat exchange device based on a fuel cell system, comprising a flow divider, a first heat exchanger, and a second heat exchanger; wherein,

[0052] The input end of the diverter cavity is connected to the output end of the burner, the first output end of the diverter cavity is connected to the first heat exchanger, and the second output end of the diverter cavity is connected to the second heat exchanger.

[0053] In some embodiments, two different types of heat exchangers and a diverter cavity are provided in the secondary heat exchange module; the input end of the diverter cavity is connected to the output end of the burner, and the output end of the diverter cavity is respectively connected to the hot side input ends of two different types of heat exchangers to realize the parallel structure of the heat exchanger; the diverter cavity is structurally designed according to the heating requirements of the heat exchanger connected thereto to realize different distribution ratios of the high-temperature exhaust gas output by the burner, and the high-temperature exhaust gas output by the burner is simultaneously output to the heat exchanger with a parallel structure, and used as a heat source to respectively exchange heat with the first substance input into the first heat exchanger in the secondary heat exchange module, and the second substance input into the second heat exchanger in the secondary heat exchange module; the first heat exchanger and the second heat exchanger output the first substance and the second substance after heat exchange to a connected device, such as a fuel cell stack; the parallel structure of the heat exchanger is realized by the diverter cavity, and the maximum temperature of the substance after heat exchange and temperature increase of the heat exchanger output is closer to the high-temperature exhaust gas temperature output by the burner, realizing a larger output temperature range design.

[0054] See also Figure 4 In some embodiments, a primary heat exchange module of a heat exchange device based on a fuel cell system provided by an embodiment of the present invention includes an evaporator, and a secondary heat exchange module includes an air heat exchanger and a gas heat exchanger; wherein,

[0055] The hot side input end of the evaporator is connected to the tail gas output end of the fuel cell stack, the cold side input end of the evaporator is connected to liquid water, the hot side output end of the evaporator is connected to the input end of the burner, and the cold side output end of the evaporator is connected to the input end of the mixer;

[0056] The output end of the burner is connected to the hot side input end of the air heat exchanger and the hot side input end of the gas heat exchanger respectively;

[0057] The output end of the pre-reformer is connected to the cold side input end of the gas heat exchanger;

[0058] The cold side input end of the air heat exchanger is connected to the air source, and the cold side output end of the air heat exchanger is connected to the input end of the fuel cell stack;

[0059] The cold side output end of the gas heat exchanger is connected to the input end of the fuel cell stack.

[0060] In some embodiments, the evaporator is used as a primary heat exchange module, and the air heat exchanger and the gas heat exchanger are used as secondary heat exchange modules; the hot side input end of the evaporator is connected to the tail gas output end of the fuel cell stack, and the hot side output end of the evaporator is connected to the input end of the burner. The evaporator uses the high-temperature tail gas output by the stack as a heat source, heats and heats the liquid water input to the evaporator, outputs high-temperature water vapor, and outputs the stack tail gas with reduced temperature to the burner, and outputs the high-temperature water vapor to the connected mixer; the burner burns the stack tail gas with reduced temperature output by the evaporator to increase the tail gas temperature, and outputs the increased temperature tail gas to the hot side input end of the air heat exchanger and the hot side input end of the gas heat exchanger at the same time, providing a heat source for the air heat exchanger and the gas heat exchanger; the input of the mixer The end is connected to the fuel source, the fuel provided by the fuel source is mixed with the high-temperature water vapor output by the evaporator, and the mixed high-temperature water vapor and fuel are output to the pre-reformer, the pre-reformer reforms the high-temperature water vapor and fuel, and outputs the reformed fuel to the gas heat exchanger connected to the pre-reformer; the gas heat exchanger uses the high-temperature exhaust gas output by the burner as a heat source to heat exchange and heat up the reformed fuel, and then the gas heat exchanger outputs the heated reformed fuel to the stack input end; the cold side input end of the air heat exchanger is connected to a fan and other equipment to provide normal temperature air for the air heat exchanger, the air heat exchanger uses the high-temperature exhaust gas output by the burner as a heat source, heat exchanges and heats up the normal temperature air input by the cold side input end, and outputs the high temperature air to the stack input end of the fuel cell through the cold side output end.

[0061] See also Figure 5 In some embodiments, the present invention provides a heat exchange device based on a fuel cell system, wherein the primary heat exchange module includes a gas heat exchanger, and the secondary heat exchange module includes an air heat exchanger and an evaporator; wherein,

[0062] The hot side input end of the gas heat exchanger is connected to the tail gas output end of the fuel cell stack, the cold side input end of the gas heat exchanger is connected to the output end of the pre-reformer, the cold side output end of the gas heat exchanger is connected to the input end of the fuel cell stack, and the hot side output end of the gas heat exchanger is connected to the input end of the burner;

[0063] The output end of the burner is connected to the hot side input end of the air heat exchanger and the hot side input end of the evaporator respectively;

[0064] The cold side input end of the air heat exchanger is connected to the air source, and the cold side output end of the air heat exchanger is connected to the input end of the fuel cell stack;

[0065] The cold side input end of the evaporator is connected to liquid water, and the cold side output end of the evaporator is connected to the input end of the mixer.

[0066] In some embodiments, a gas heat exchanger is used as a primary heat exchange module, and an air heat exchanger and an evaporator are used as secondary heat exchange modules; the input end of the gas heat exchanger is connected to the tail gas output end of the fuel cell stack, and the high-temperature tail gas output from the tail gas output end of the fuel cell stack is used as a heat source to heat exchange and heat up the reformed fuel output from the output end of the pre-reformer; the input end of the pre-reformer is connected to the output end of the mixer, and the input end of the mixer is respectively connected to the fuel source and the cold side output end of the evaporator, and the fuel provided by the fuel source and the high-temperature water vapor output from the evaporator are mixed and output to the pre-reformer; the pre-reformer reforms the fuel and the high-temperature water vapor to obtain the reformed fuel, and outputs the reformed fuel to the gas heat exchanger; after the gas heat exchanger heats up the reformed fuel, the heated reformed fuel is output to the pre-reformer. The exhaust gas is output to the input end of the fuel cell stack, and the exhaust gas of the fuel cell stack that has been cooled by heat exchange is output to the connected burner; the burner burns and heats the exhaust gas of the fuel cell stack that has been cooled by heat exchange to obtain high-temperature exhaust gas, and outputs the high-temperature exhaust gas to the air heat exchanger and evaporator at the same time, providing heat source for the air heat exchanger and evaporator; the evaporator uses the high-temperature exhaust gas output by the burner as a heat source to heat and heat the liquid water input to the evaporator to obtain high-temperature water vapor, and outputs the high-temperature water vapor to the mixer; the air heat exchanger uses the high-temperature exhaust gas output by the burner as a heat source to heat and heat the normal-temperature air provided by the fan and other equipment into high-temperature air, and outputs the high-temperature air to the input end of the fuel cell stack, and the fuel cell uses the high-temperature air at the input end of the fuel cell stack and the high-temperature reforming fuel to perform electrochemical reaction to generate electricity.

[0067] See also Figure 6 In some embodiments, a secondary heat exchange module in a heat exchange device based on a fuel cell system provided by an embodiment of the present invention includes a third heat exchanger and a fourth heat exchanger; wherein,

[0068] The hot side input end of the third heat exchanger is connected to the output end of the burner, and the hot side output end of the third heat exchanger is connected to the hot side input end of the fourth heat exchanger.

[0069] In some embodiments, different types of heat exchangers in the secondary heat exchange module can be set to a series structure, and the hot side input end of any heat exchanger is connected to the output end of the burner, and the hot side output end of the heat exchanger is connected to the hot side input end of any other heat exchanger, and so on, to obtain a secondary heat exchange module with a series structure; the first heat exchanger in the series structure uses the high-temperature exhaust gas output by the burner as a heat source to heat exchange and heat up the substance (the third substance) input into the heat exchanger, and outputs the heat exchanged and cooled burner exhaust gas to the next connected heat exchanger, and the next heat exchanger uses the heat exchanged and cooled burner exhaust gas as a heat source to heat exchange and heat up the input substance (the fourth substance), until the burner exhaust gas is output to the last heat exchanger in the series structure, and is used as a heat source to heat exchange and heat up the substance input into the last heat exchanger; the exhaust gas temperature of the burner in the series-structured secondary heat exchange module is significantly reduced step by step, which can be applied to scenarios with low temperature requirements.

[0070] In some embodiments, the exhaust gas output end of a fuel cell system in a fuel cell-based heat exchange device system provided in an embodiment of the present invention includes an anode output end and a cathode output end; both the anode output end and the cathode output end output the stack exhaust gas, and the anode exhaust gas output from the anode output end and the cathode exhaust gas output from the cathode output end can be output to a primary heat exchange module for heat exchange; in this embodiment, the anode exhaust gas is used for heat exchange.

[0071] See also Figure 7 In some embodiments, the anode output end of a heat exchange device based on a fuel cell system provided by an embodiment of the present invention is connected to the hot side input end of a primary heat exchange module, and the cathode output end is connected to the input end of a burner.

[0072] In some embodiments, the anode exhaust gas output from the anode output end of the fuel cell stack and the cathode exhaust gas output from the cathode output end can both be used as heat sources for a primary heat exchange module for heat exchange; optionally, the anode output end of the fuel cell stack is connected to the hot side input end of the primary heat exchange module, the output anode exhaust gas is used as a heat source for the primary heat exchange module for heat exchange, and the anode exhaust gas after heat exchange and cooling is output to a burner; the cathode output end of the fuel cell stack is connected to the input end of the burner, and the cathode exhaust gas is output to the burner, where the burner burns and heats the input cathode exhaust gas and anode exhaust gas, and outputs high-temperature exhaust gas to the connected secondary heat exchange module.

[0073] See also Figure 8 In some embodiments, the cathode output end of a heat exchange device based on a fuel cell system provided by an embodiment of the present invention is connected to the hot side input end of a primary heat exchange module, and the anode output end is connected to the input end of a burner.

[0074] In some embodiments, the cathode output end of the fuel cell stack is connected to the hot side input end of the first-level heat exchange module, and the anode output end is connected to the input end of the burner. The cathode exhaust gas output from the cathode output end is used as a heat source for the first-level heat exchange module for heat exchange and cooling, and then output to the burner for combustion and temperature increase with the anode exhaust gas, and then output to the second-level heat exchange module through the output end of the burner. Since the flow rate of the cathode exhaust gas output from the cathode output end of the fuel cell stack is larger than that of the anode exhaust gas output from the anode output end, the average temperature difference of the heat transfer using the cathode exhaust gas as a heat source is larger, and the temperature drop of the cathode exhaust gas is smaller, thereby reducing the volume and design difficulty of the first-level heat exchange module.

[0075] Implementation of the embodiments of the present invention includes the following beneficial effects: the present embodiment provides a heat exchange device and system based on a fuel cell system, the device is provided with a primary heat exchange module, a burner and a secondary heat exchange module; the hot side input end of the primary heat exchange module is connected to the exhaust gas output end of the stack, and the hot side output end of the primary heat exchange module is connected to the input end of the burner; the output end of the burner is connected to the hot side input end of the secondary heat exchange module, and the cold side output end of the secondary heat exchange module is connected to the input end of the fuel cell stack; by providing a primary heat exchange module between the exhaust gas output end of the fuel cell stack and the burner, the exhaust gas temperature entering the burner is lowered by the primary heat exchange module, thereby reducing the combustion temperature of the burner and the output exhaust gas temperature, reducing the over-temperature risk of the burner, and improving the operating stability of the heat exchange device; at the same time, reducing the combustion temperature of the burner and the output exhaust gas temperature, reducing the heat resistance requirements of each component in the burner and the heat exchange module, and reducing the implementation cost of the heat exchange device.

[0076] like Fig. 9 As shown, an embodiment of the present invention further provides a fuel cell system, the system includes a fuel cell stack and a heat exchange network; wherein,

[0077] A fuel cell stack, used to generate electricity and produce fuel cell tail gas;

[0078] The heat exchange network includes any of the devices described above, and is used to exchange heat with the fuel according to the fuel stack exhaust gas.

[0079] The heat exchange network recovers energy from the high-temperature stack exhaust gas generated by the fuel cell, thereby improving the energy utilization rate of the fuel cell; the heat exchange network uses the high-temperature stack exhaust gas to reform the fuel input to the fuel cell, converting it into low-carbon substances, and uses the high-temperature stack exhaust gas to heat the fuel and air input to the fuel cell to the fuel cell stack operating temperature, thereby improving the efficiency of the fuel cell.

[0080] The above is a specific description of the preferred implementation of the present invention, but the invention is not limited to the embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A heat exchange device, characterized in that: The heat exchange device is connected to the fuel cell stack, and the device includes a primary heat exchange module, a burner, and a secondary heat exchange module; wherein, The hot side input end of the first-stage heat exchange module is connected to the tail gas output end of the fuel cell stack, and the hot side output end of the first-stage heat exchange module is connected to the input end of the burner; The output end of the burner is connected to the hot side input end of the secondary heat exchange module; The cold side output end of the secondary heat exchange module is connected to the input end of the fuel cell stack.

2. The device according to claim 1, characterized in that The secondary heat exchange module includes a diversion chamber, a first heat exchanger and a second heat exchanger; wherein, The input end of the diverter cavity is connected to the output end of the burner, the first output end of the diverter cavity is connected to the first heat exchanger, and the second output end of the diverter cavity is connected to the second heat exchanger.

3. The device according to claim 1, characterized in that The secondary heat exchange module includes a third heat exchanger and a fourth heat exchanger; wherein, The hot side input end of the third heat exchanger is connected to the output end of the burner, and the hot side output end of the third heat exchanger is connected to the hot side input end of the fourth heat exchanger.

4. The device according to claim 1, characterized in that The primary heat exchange module includes an evaporator; wherein, The hot side input end of the evaporator is connected to the tail gas output end of the fuel cell stack, the cold side input end of the evaporator is connected to liquid water, and the hot side output end of the evaporator is connected to the input end of the burner.

5. The device according to claim 1, characterized in that The device further comprises a pre-reformer, and the primary heat exchange module comprises a gas heat exchanger; wherein, The hot side input end of the gas heat exchanger is connected to the exhaust gas output end of the fuel cell stack, the cold side input end of the gas heat exchanger is connected to the output end of the pre-reformer, the cold side output end of the gas heat exchanger is connected to the input end of the fuel cell stack, and the hot side output end of the gas heat exchanger is connected to the input end of the burner.

6. The device according to claim 5, characterized in that The device further comprises a mixer, and the secondary heat exchange module comprises an air heat exchanger and an evaporator; wherein, The output end of the burner is respectively connected to the hot side input end of the air heat exchanger and the hot side input end of the evaporator; The cold side input end of the air heat exchanger is connected to an air source, and the cold side output end of the air heat exchanger is connected to the input end of the fuel cell stack; The cold side input end of the evaporator is connected to liquid water, and the cold side output end of the evaporator is connected to the input end of the mixer; The mixer is used to mix fuel and high-temperature water vapor; the first input end of the mixer is connected to the fuel source, the second input end of the mixer is connected to the output end of the water evaporator, and the output end of the mixer is connected to the input end of the pre-reformer; The pre-reformer is used to reform the fuel to obtain reformed fuel; the output end of the pre-reformer is connected to the primary heat exchange module or the secondary heat exchange module.

7. The device according to claim 1, characterized in that The tail gas output end of the fuel cell system includes an anode output end and a cathode output end.

8. The device according to claim 7, characterized in that The anode output end is connected to the hot side input end of the primary heat exchange module, and the cathode output end is connected to the input end of the burner.

9. The device according to claim 7, characterized in that The cathode output end is connected to the hot side input end of the primary heat exchange module, and the anode output end is connected to the input end of the burner.

10. A fuel cell system, characterized in that: The system includes a battery stack and a heat exchange network; wherein, The fuel cell stack is used to generate electricity and produce fuel cell tail gas; The heat exchange network comprises the device according to any one of claims 1 to 9, which is used to exchange heat with the fuel according to the fuel cell tail gas.

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