Low-temperature cold start system of fuel cell

Abstract

The utility model discloses a fuel cell low-temperature cold start system which comprises a first fuel cell stack and a heat management assembly used for controlling the internal temperature of the first fuel cell stack, the heat management assembly comprises a heating unit, the heating unit is connected with a second fuel cell stack in parallel, and the second fuel cell stack is connected with the first fuel cell stack in parallel. The power of the second fuel cell stack is smaller than that of the first fuel cell stack; and the air heater is used for heating the second fuel cell stack. By means of the scheme, the vehicle can enter the driving state as soon as possible, the in-situ waiting time of vehicle starting is shortened, and the vehicle using experience of customers in extremely cold areas is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of fuel cell cold start, in particular to a fuel cell low-temperature cold start system. Background Art

[0002] A hydrogen fuel cell is a power generation device that directly converts the chemical energy of hydrogen and oxygen into electrical energy. The anode and cathode are made of porous carbon or metal materials, and the electrolyte is a liquid or solid polymer that can conduct ions. When hydrogen enters the anode of the battery through a pipeline, under the action of a catalyst, the hydrogen molecules decompose into protons and electrons. The protons migrate to the cathode through the electrolyte, and the electrons flow through an external circuit to form an electric current, combining with oxygen to form water. However, when the fuel cell operates in a low-temperature environment, the moist moisture in the proton exchange membrane and the water generated by the cathode reaction can easily reach the freezing point, causing the proton exchange membrane and gas diffusion layer to be blocked, hindering the subsequent reaction. The phase change process of water freezing accompanied by volume expansion will also cause irreversible damage to the internal structure of the fuel cell stack, reducing the performance and life of the fuel cell.

[0003] In order to solve the low-temperature cold start problem of fuel cells, the current method is to use the discharge of the on-board lithium-ion battery to drive the PTC heater to heat the fuel cell. However, under working conditions in extremely cold areas, the discharge capacity of the lithium-ion battery is also very limited, and external discharge is even directly prohibited. The on-board control system is forced to execute a serial working mode of first performing PTC heating on the lithium-ion battery itself, and then discharging it to the outside to heat the fuel cell when the temperature rises to a certain value and has the discharge capacity. Due to the relatively large size of the lithium-ion battery and fuel cell system, the system components need to be heated on site, which takes too long, affecting the user experience of the vehicle terminal. Utility Model Content

[0004] The purpose of the utility model is to overcome the shortcomings of the prior art and provide a low-temperature cold start system for a fuel cell.

[0005] The purpose of this utility model is achieved through the following technical solutions:

[0006] The utility model provides a fuel cell low-temperature cold start system, comprising a first fuel cell stack and a thermal management component for controlling the internal temperature of the first fuel cell stack, the thermal management component comprising a heating unit, a second fuel cell stack connected in parallel to the heating unit, the power of the second fuel cell stack being less than the power of the first fuel cell stack; and a hot air blower for heating the second fuel cell stack.

[0007] The utility model has the following advantages:

[0008] This solution adds a second fuel cell stack heater with lower power to the system. Before starting under extremely cold conditions, the hot air blower provides hot air to the second fuel cell stack to complete the cold start of the low-power fuel cell stack first. When the low-power fuel cell stack reaches the rated operating condition, the heating cycle mode can be started to exchange the converted heat of the heating unit to the inside of the first fuel cell stack until the temperature difference between the liquid inlet and the liquid outlet of the first fuel cell stack is small and the absolute temperature reaches the low-load starting temperature threshold of the first fuel cell stack. The first fuel cell stack is started. The above solution can enable the vehicle to enter a drivable state as soon as possible, shorten the waiting time for the vehicle to start, and improve the car-using experience of customers in extremely cold areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0010] Figure 1 This is a schematic structural diagram of the low-temperature cold start system for a fuel cell according to the present invention. DETAILED DESCRIPTION

[0011] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0012] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but rather merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0013] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0014] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0015] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the product of the present invention is typically placed when in use, or are the orientations or positional relationships commonly understood by those skilled in the art. These terms are intended solely to facilitate the description of the present invention and to simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like are used solely to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0016] It should also be noted that, in the description of this utility model, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; direct connections, indirect connections through an intermediate medium, and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on the specific circumstances.

[0017] The utility model discloses a fuel cell low temperature cold start system, such as Figure 1 As shown, the system includes a first fuel cell stack 4, a thermal management component, a second fuel cell stack 9, and a hot air blower 8. The thermal management component is used to control the internal temperature of the first fuel cell stack and includes a heating unit 7; the second fuel cell stack 9 is connected in parallel to the heating unit; and the hot air blower 8 is used to heat the second fuel cell stack.

[0018] The power of the second fuel cell stack is less than that of the first fuel cell stack. Generally, the power of the first fuel cell stack 4 is greater than or equal to 100 kW and less than or equal to 300 kW. The power of the second fuel cell stack is a small-volume power source module, fully utilizing the onboard hydrogen resources. The second fuel cell stack preferably has a power greater than or equal to 5 kW and less than or equal to 10 kW, so that it can quickly complete a cold start and reach the rated operating state with the cooperation of the hot air blower.

[0019] The thermal management component is used to control the internal temperature of the first fuel cell stack, which can be implemented using existing technology. For example, Figure 1As shown, the thermal management component includes a water supply unit, a data acquisition unit, a thermostat 6, a heat dissipation unit 10, and a heating unit. The water supply unit is used to supply water to the first fuel cell stack 4. The data acquisition unit is used to collect the temperatures at the liquid inlet and outlet of the first fuel cell stack 4. For example, a first temperature sensor 3 and a second temperature sensor 5 can be installed at the liquid inlet and outlet of the first fuel cell stack 4, respectively, to collect the inlet and outlet temperatures. The thermostat automatically adjusts the amount of water entering the radiator based on the cooling water temperature, changing the water circulation range to adjust the cooling system's heat dissipation capacity and ensure that the engine operates within the appropriate temperature range. The thermostat has two outlets. The thermostat's inlet is connected to the liquid outlet of the first fuel cell stack 4. The first outlet of the thermostat is connected to the heating unit 7, and the second outlet is connected to the heat dissipation unit 10. The outlets of the heat dissipation unit and the heating unit 7 are connected to the water supply unit to form a circulation loop.

[0020] The heating unit may be a PTC heater.

[0021] In order to facilitate the replenishment of water in the circulation loop, the water supply unit includes a water supply tank 1 and a water pump 2 connected to the water supply tank. In order to further realize the liquid level detection in the water supply tank and timely replenishment, the water supply tank 1 is provided with a liquid level sensor.

[0022] In order to improve the heat dissipation performance of the heat dissipation unit, an electronic brushless fan is provided on the heat dissipation unit 10 .

[0023] Using the above solution, the cold start method is divided into two steps. The first step is to concentrate power to complete a rapid cold start of a low-power fuel cell, namely the second fuel cell stack 9, and wait for the low-power fuel cell to reach the rated operating conditions. The second step is to start the cold start of the high-power fuel cell, namely the first fuel cell stack. The lithium-ion battery can heat its own system at the same time to meet the buffer fuel cell power requirements at a faster speed, thereby improving the vehicle's system startup and power loading performance as a whole, and helping to expand the applicable scenarios of fuel cell vehicles.

[0024] Specifically, before the high-power automotive fuel cell stack is started under extremely cold conditions, the heating wire inside the hot air blower is energized and heated to provide hot air to the low-power fuel cell stack, giving priority to completing the cold start of the small-power fuel cell. After the small-power fuel cell reaches the rated operating condition, the second liquid outlet of the thermostat is closed, the first liquid outlet is opened, and the water pump is started to drive the water circuit to the heating circulation mode, and the heat converted by the PTC heater is exchanged to the inside of the fuel cell until the difference between the stack inlet temperature and the outlet temperature is small and the absolute temperature reaches the low-load starting temperature threshold of the high-power fuel cell. The high-power fuel cell is started, and the dual heat sources cooperate to make the temperature of the high-power fuel cell continue to rise to the rated operating temperature point. After the high-power fuel cell enters the normal working mode, the cold start is completed, the hot air blower and the low-power fuel cell are turned off, the PTC heater stops working, the first liquid outlet of the thermostat is closed, the second liquid outlet is opened, and the water circuit is switched to the heat dissipation circulation mode.

[0025] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A fuel cell low-temperature cold start system, comprising a first fuel cell stack (4) and a thermal management component for controlling the internal temperature of the first fuel cell stack, the thermal management component comprising a heating unit (7), characterized in that: A second fuel cell stack (9) is connected in parallel to the heating unit, the power of the second fuel cell stack being less than the power of the first fuel cell stack; It also includes a hot air blower (8) for heating the second fuel cell stack.

2. A fuel cell low-temperature cold start system according to claim 1, characterized in that: The heating unit is a PTC heater.

3. A fuel cell low-temperature cold start system according to claim 1 or 2, characterized in that: The thermal management assembly further comprises: a water supply unit for supplying water to the first fuel cell stack (4); A data acquisition unit for acquiring the temperature of the liquid inlet and the liquid outlet of the first fuel cell stack (4); a thermostat (6) whose liquid inlet is connected to the liquid outlet of the first fuel cell stack (4), and the heating unit (7) is connected to the first liquid outlet of the thermostat; A heat dissipation unit (10) is connected to the second liquid outlet of the thermostat, and the liquid outlets of the heat dissipation unit and the heating unit (7) are in communication with the water supply unit.

4. A fuel cell low-temperature cold start system according to claim 3, characterized in that: The water supply unit comprises a water supply tank (1) and a water pump (2) connected to the water supply tank, and a liquid level sensor is provided on the water supply tank (1).

5. A fuel cell low-temperature cold start system according to claim 3, characterized in that: The heat dissipation unit (10) is provided with an electronic brushless fan.

6. A fuel cell low-temperature cold start system according to claim 1, characterized in that: The power of the first fuel cell stack (4) is greater than or equal to 100 kW and less than or equal to 300 kW.

7. A fuel cell low-temperature cold start system according to claim 1 or 6, characterized in that: The power of the second fuel cell stack (9) is greater than or equal to 5 kW and less than or equal to 10 kW.

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