A device for improving the adaptability of air-cooled fuel cell stack to low temperature environment

Abstract

A device for improving the adaptability of an air-cooled fuel cell stack to a low-temperature environment includes a shell, one end of the shell is provided with an opening, a partition is provided in the shell along the axial direction of the opening, the partition divides the middle part of the inner cavity of the shell into an air inlet channel and an exhaust channel, a stack is provided on one side of the partition and at the entrance of the exhaust channel, a fan is provided in the exhaust channel, a baffle is provided in the shell, a rotating shaft is fixedly connected to the baffle, and a rotating shaft rotation drive mechanism is provided between the rotating shaft and the shell. The device for improving the adaptability of an air-cooled fuel cell stack to a low-temperature environment of the present invention recycles the heat released by the fuel cell itself during operation without additional heating, so that the fuel cell can maintain a higher operating temperature in a low-temperature environment, operate stably, and break the limitation of the low-temperature environment on the air-cooled fuel cell. The higher intake temperature makes the temperature of the front and rear sides of the fuel cell stack more uniform, which can increase its service life.

Description

Technical Field

[0001] The present invention relates to the field of electricity, in particular to an air-cooled fuel cell, and specifically to a device for improving the adaptability of an air-cooled fuel cell stack to a low-temperature environment. Background Art

[0002] Proton exchange membrane fuel cell is a device that directly converts the chemical energy of hydrogen and oxygen in the air into electrical energy. It has the advantages of high energy conversion efficiency, no pollution, low noise, safety and reliability, etc., which has attracted widespread attention and has been widely used in many fields. The existing fuel cell structures are mainly divided into two categories: cathode open fuel cell and cathode closed fuel cell. The cathode closed fuel cell has a special cooling channel, water pump, radiator, cooling water tank, etc. The system has good environmental adaptability and stability, but the cooling system greatly increases the complexity of the battery stack structure and control system. It is generally used in relatively large fuel cell systems, such as automotive, backup power supply, etc. The cathode open fuel cell, which is what we call air-cooled fuel cell, has a special structural design. The air is inhaled through the fan, which is not only used as the reaction gas of the fuel cell, but also can take away the heat generated by the reaction to cool the battery, combining air supply and system heat dissipation into one, simplifying the system, and is particularly suitable for applications that are sensitive to weight, such as portable fuel cells and drones. However, the stoichiometric ratio of the air flow on the cathode side of this type of battery is generally high, with more than ten times or even hundreds of times the stoichiometric ratio of air flowing through the battery. This type of fuel cell is greatly affected by the ambient temperature of use, especially in a low-temperature environment. Due to the inhalation of a large amount of low-temperature air, the fuel cell system dissipates too much heat, and the fuel cell cannot maintain a suitable operating temperature. When the operating temperature of the fuel cell stack is too low, the moisture generated by the fuel cell air side cannot be discharged from the cathode in time, causing the cathode to flood, resulting in performance degradation or even reverse polarity, and even ice on the cathode side, making it impossible for the fuel cell to operate for a long time at low temperatures. The ambient temperature of air-cooled fuel cell products currently reported is mostly between 0-40°C, which cannot meet the use in low-temperature environments. In addition, even above zero degrees Celsius, if the room temperature is low, such as below 10°C, the air-cooled fuel cell stack will cause uneven temperatures on the air intake and outlet sides of the stack due to the low air intake temperature. The uneven stack temperature will not only affect the performance output of the fuel cell, but also damage the life of the fuel cell. Patent WO2014 / 184549A1 submitted by Smart Energy Co., Ltd. mentioned the use of plasma discharge fans to change the exhaust gas of the open cathode of the stack multiple times to preheat the stack, and CN104662722A mentioned the use of multiple sets of fans to change the air intake and outlet of the cathode of the stack, and to preheat the stack multiple times. However, the cathode cooling air duct of the stack mentioned in the two patents is used to input fresh air and return the preheated circulating air at the same time, which can easily lead to uneven airflow on the cathode side, and the concentration of the cathode side of the stack is quite different, which affects the performance and life of the stack. In order to achieve this function, multiple sets of fans are required to cooperate, and the structure is very complicated. It is not suitable for portable fuel cell systems with relatively low power and only 1-2 small fans. Summary of the invention

[0003] The purpose of the present invention is to provide a device for improving the adaptability of an air-cooled fuel cell stack to a low-temperature environment. The device for improving the adaptability of an air-cooled fuel cell stack to a low-temperature environment is intended to solve the technical problem in the prior art that air-cooled fuel cells cannot operate for a long time in a low-temperature environment.

[0004] A device for improving the adaptability of an air-cooled fuel cell stack to a low-temperature environment of the present invention comprises a shell, one end of the shell is provided with an opening, a partition is provided in the shell along the axial direction of the opening, the partition divides the middle part of the inner cavity of the shell into an air inlet channel and an exhaust channel, a stack is provided on one side of the partition and at the entrance of the exhaust channel, the air inlet of the stack is arranged opposite to the closed end of the shell and is connected to the air inlet channel, a fan is provided in the exhaust channel, a baffle is provided in the shell, the baffle is located between the baffle and the opening of the shell, a rotating shaft is fixedly connected to the baffle, the rotating shaft is perpendicular to the axial direction of the opening of the shell, the rotating shaft is connected to the shell, and a rotating shaft rotation drive mechanism is provided between the rotating shaft and the shell.

[0005] Furthermore, the shaft rotation drive mechanism includes a controller and a motor, the motor and the shell are fixedly arranged relative to each other, the shaft is connected to the output shaft of the motor through a transmission mechanism, the control end of the motor is connected to the signal output end of the controller, a temperature sensor is arranged outside the shell, and the signal output end of the temperature sensor is connected to the signal input end of the controller.

[0006] Furthermore, the baffle includes a first baffle and a second baffle, the first baffle and the second baffle are respectively arranged in the exhaust channel and the air inlet channel, the rotating shaft includes a first rotating shaft and a second rotating shaft, the first baffle and the second baffle are respectively fixedly connected to the first rotating shaft and the second rotating shaft.

[0007] Furthermore, the shaft rotation drive mechanism includes a controller, a first motor and a second motor. The first shaft is connected to the output shaft of the first motor through a first transmission mechanism, and the second shaft is connected to the output shaft of the second motor through a second transmission mechanism. The control end of the motor is connected to the signal output end of the controller. A temperature sensor is provided outside the shell, and the signal output end of the temperature sensor is connected to the signal input end of the controller.

[0008] Alternatively, the baffle is composed of a large-diameter baffle, and the diameter of the large-diameter baffle is larger than the diameter of the exhaust passage and the diameter of the air inlet passage.

[0009] Furthermore, the inner wall of the closed end of the shell is a concave arc surface.

[0010] Compared with the prior art, the effect of the present invention is positive and obvious. A device for improving the adaptability of an air-cooled fuel cell stack to a low-temperature environment of the present invention recycles the heat released by the fuel cell itself during operation without additional heating, so that the fuel cell can maintain a higher operating temperature in a low-temperature environment, operate stably, and break the limitation of the low-temperature environment on air-cooled fuel cells. The higher intake temperature makes the temperature of the front and rear sides of the fuel cell stack more uniform, which can increase its service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the flat state of the first baffle and the second baffle in a device for improving the adaptability of an air-cooled fuel cell stack to a low-temperature environment of the present invention.

[0012] Figure 2 It is a schematic diagram of the state after the first baffle and the second baffle in the device for improving the adaptability of an air-cooled fuel cell stack to a low-temperature environment of the present invention are rotated.

[0013] Figure 3 It is a schematic diagram of the state after the large diameter baffle in the device for improving the adaptability of an air-cooled fuel cell stack to a low-temperature environment of the present invention is rotated. DETAILED DESCRIPTION

[0014] The present invention is further described below in conjunction with the accompanying drawings and embodiments, but the present invention is not limited to these embodiments, and all similar structures and similar variations of the present invention should be included in the protection scope of the present invention.

[0015] Example 1

[0016] like Figure 1 , Figure 2 and Figure 3 As shown, a device for improving the adaptability of an air-cooled fuel cell stack to a low-temperature environment of the present invention comprises a shell 6, an opening is provided at one end of the shell 6, a partition 8 is provided in the shell 6 along the axial direction of the opening, the partition 8 divides the middle part of the inner cavity of the shell 6 into an air inlet channel 7 and an exhaust channel 2, a stack 4 is provided on one side of the partition 8 and at the entrance of the exhaust channel 2, the air inlet of the stack 4 is arranged opposite to the closed end of the shell 6 and is connected to the air inlet channel 7, a fan 3 is provided in the exhaust channel 2, a baffle is provided in the shell 6, the baffle is located between the baffle 8 and the opening of the shell 6, a rotating shaft is fixedly connected to the baffle, the rotating shaft is perpendicular to the axial direction of the opening of the shell 6, the rotating shaft is connected to the shell 6, and a rotating shaft rotation driving mechanism is provided between the rotating shaft and the shell 6.

[0017] Furthermore, the shaft rotation drive mechanism includes a controller and a motor, the motor is fixedly arranged relative to the shell 6, the shaft is connected to the output shaft of the motor through a transmission mechanism, the control end of the motor is connected to the signal output end of the controller, and a temperature sensor is arranged outside the shell 6, and the signal output end of the temperature sensor is connected to the signal input end of the controller.

[0018] Furthermore, the baffle includes a first baffle 1 and a second baffle 9, which are respectively arranged in the exhaust channel 2 and the air inlet channel 7, and the rotating shaft includes a first rotating shaft and a second rotating shaft, and the first baffle 1 and the second baffle 9 are respectively fixedly connected to the first rotating shaft and the second rotating shaft.

[0019] Furthermore, the shaft rotation drive mechanism includes a controller, a first motor and a second motor. The first shaft is connected to the output shaft of the first motor through a first transmission mechanism, and the second shaft is connected to the output shaft of the second motor through a second transmission mechanism. The control end of the motor is connected to the signal output end of the controller. A temperature sensor is provided outside the shell 6, and the signal output end of the temperature sensor is connected to the signal input end of the controller.

[0020] Alternatively, the baffle is composed of a large-diameter baffle 10 , and the diameter of the large-diameter baffle 10 is larger than the diameter of the exhaust passage 2 and the diameter of the air inlet passage 7 .

[0021] Furthermore, the inner wall of the closed end of the shell 6 is a concave arc surface 5.

[0022] Specifically, the fan 3, the battery stack 4, the controller, the motor, the transmission mechanism, the temperature sensor, etc. in this embodiment all adopt well-known solutions in the prior art, which are well known to those skilled in the art and will not be described in detail here.

[0023] The working principle of this embodiment:

[0024] like Figure 1 As shown, the air inlet channel 7 and the air outlet channel 2 of the device are separated. When the ambient temperature is very high, or the air inlet temperature does not need to be adjusted, the first baffle 1 and the second baffle 9 are laid flat, and then air enters from the air inlet channel 7, passes through the concave arc surface 5 and enters the fuel cell stack 4. A small part of the air oxygen enters the fuel cell stack 4 and is consumed by the fuel cell stack 4. As a reactant, it passes through the gas diffusion layer and enters the cathode of the fuel cell, where an electrochemical reaction occurs to generate water. In addition, most of the air is heat exchanged to extract the waste heat generated in the fuel cell stack 4, which can take away the heat of the fuel cell stack 4 and then be discharged from the exhaust channel 2 through the fan 3.

[0025] like Figure 2As shown, in a low-temperature environment, after the fuel cell is successfully started at low temperature, the angle of the first baffle 1 can be adjusted to adjust the opening ratio of the exhaust channel 2, and the angle of the second baffle 9 can be adjusted to adjust the opening ratio of the air inlet channel 7. Part or all of the hot air discharged by the stack 4 is changed by the first baffle 1 and enters the air inlet channel 7 of the fuel cell, and merges with the incoming fresh air in the air inlet channel 7 to achieve oxygen replenishment, and then is sucked into the stack 4. By adjusting the position of the first baffle 1 and the second baffle 9, the mixing ratio of fresh air intake and hot air discharged by the stack 4 can be achieved, thereby controlling the temperature of the stack 4 intake, achieving normal operation of the stack 4 in a low-temperature environment, and fresh air is constantly replenished into the stack 4 intake, which can avoid a small amount of air from circulating multiple times inside the fuel cell, resulting in too low oxygen concentration, so as to meet different power outputs. Of course, different stacks 4, different power outputs, and different ambient temperatures will have different requirements for the mixing ratio of hot air and cold air, and the rotation angles of the first baffle 1 and the second baffle 9 will be different, and the opening ratio of the air inlet channel 7 or the exhaust channel 2 will also be different, which should be adjusted according to actual conditions. The operating temperature of the air-cooled fuel cell stack 4 is generally 40 o C-65 o C. Under different power and current output, the suitable operating temperature of the fuel cell stack 4 will be slightly different, but the overall operating temperature is between 40-75 o Within C range.

[0026] In addition, if Figure 3 As shown, only a large-diameter baffle 10 is provided. By adjusting the angle of the large-diameter baffle 10, mixing of the incoming air and the outgoing air in the air inlet passage 7 can also be achieved, which is also within the scope of protection of the present invention.

[0027] The present invention can also monitor the temperature of the operating environment through a temperature sensor. The controller intelligently adjusts the angles of the first baffle 1, the second baffle 9 and the large diameter baffle 10 through the first motor, the second motor and the third motor according to the temperature provided by the temperature sensor. The stack exhaust control valve and the exhaust pipe can be arranged in the air inlet channel 7 to avoid ice blockage when used in a low temperature environment.

[0028] The operating results of the present invention in different parameters and environments are as follows:

[0029] At -40 o C environment, the position of the second baffle 9 is adjusted so that the opening area of ​​the exhaust channel 2 accounts for 20% of the overall area of ​​the exhaust channel 2, and the remaining hot air passes through the second baffle 9 to block the air inlet channel 7, and the opening ratio of the air inlet channel 7 is also 20%. The temperature of the battery stack 4 during operation is 65 o C, the stack 4 outputs 100W, and the stack 4 intake temperature can be maintained at 40 oC, and ran continuously for 20 hours. The internal temperature of the fuel cell stack 4 was uniform, the output was stable, and the performance did not decrease.

[0030] At -20 o C environment, adjust the position of the second baffle 9 so that the opening area of ​​the exhaust channel 2 accounts for 30% of the total area of ​​the exhaust channel 2, and the remaining hot air passes through the blockage and enters the air inlet channel 7. The opening of the air inlet channel 7 accounts for 30%. The temperature of the battery stack 4 during operation is 55 o C, the stack 4 output is 80W, and the stack 4 intake temperature can be maintained at 35 o C, and run continuously for 24 hours. The internal temperature of the battery stack 4 is uniform, the output is stable, and the performance does not decrease.

[0031] At room temperature 5 o C environment, the position of the second baffle 9 is adjusted so that the opening area of ​​the exhaust channel 2 accounts for 50%, and the remaining hot air passes through the blockage and enters the air inlet channel 7. The opening area of ​​the air inlet channel 7 accounts for 30%. The temperature of the battery stack 4 during operation is 55 o C, the stack 4 output is 80W, and the stack 4 intake temperature can be maintained at 30 o C, and continuously run for 10 hours. The temperature inside the stack 4 is uniform, the output is stable, and the performance is improved by 20% compared with when the second baffle 9 and the baffles of the air inlet channel 7 are both placed flat.

[0032] In -20 o C environment, adjust the position of the second baffle 9 so that the opening area of ​​the exhaust channel 2 accounts for 30% of the total area of ​​the exhaust channel 2, and the opening area of ​​the air inlet channel 7 accounts for 30% of the total area of ​​the exhaust channel 2. The operating temperature of the battery stack 4 is 65 o C, the stack 4 outputs 100W, and the stack 4 intake temperature can be maintained at 35 o C, and run continuously for 24 hours. The internal temperature of the battery stack 4 is uniform, the output is stable, and the performance does not decrease.

[0033] It should be understood that the present invention is not only applicable to low temperature environments, but any application improved according to the above description for changing the intake temperature of the stack 4 or stabilizing the internal temperature of the stack 4 shall fall within the protection scope of the claims attached to the present invention. In addition, the application of changing the intake temperature by mixing the hot air discharged from the stack 4 with the incoming air shall also fall within the protection scope of the claims attached to the present invention even if the mixing position and mixing method are different.

Claims

1. A device for improving the adaptability of an air-cooled fuel cell stack to a low-temperature environment, comprising a housing (6), characterized in that: An opening is provided at one end of the shell (6), and a partition (8) is provided in the shell (6) along the axial direction of the opening. The partition (8) divides the middle part of the inner cavity of the shell (6) into an air inlet channel (7) and an air exhaust channel (2). A battery stack (4) is provided on one side of the partition (8) and at the entrance of the air exhaust channel (2). The air inlet of the battery stack (4) is arranged opposite to the closed end of the shell (6) and is connected to the air inlet channel (7). A fan (3) is provided in the air exhaust channel (2). A baffle is provided in the shell (6), and the baffle is located between the baffle (8) and the opening of the shell (6). A rotating shaft is fixedly connected to the baffle, and the rotating shaft is perpendicular to the axial direction of the opening of the shell (6). The rotating shaft is connected to the shell (6), and a rotating shaft rotation drive mechanism is provided between the rotating shaft and the shell (6); the rotating shaft rotation drive mechanism comprises a controller and a motor. The motor and the housing (6) are relatively fixedly arranged, the rotating shaft is connected to the output shaft of the motor through a transmission mechanism, the control end of the motor is connected to the signal output end of the controller, a temperature sensor is arranged outside the housing (6), and the signal output end of the temperature sensor is connected to the signal input end of the controller; a stack exhaust control valve and an exhaust pipe are arranged in the air inlet channel (7); the inner wall of the closed end of the housing (6) is an arc surface (5) or a plane, and at least one protrusion or recessed portion is arranged on the inner wall; the baffle comprises a first baffle (1) and a second baffle (9), the first baffle (1) and the second baffle (9) are respectively arranged in the exhaust channel (2) and the air inlet channel (7), the rotating shaft comprises a first rotating shaft and a second rotating shaft, and the first baffle (1) and the second baffle (9) are respectively fixedly connected to the first rotating shaft and the second rotating shaft.

2. The device for improving the low temperature environment adaptability of an air-cooled fuel cell stack according to claim 1, characterized in that: The shaft rotation drive mechanism comprises a controller, a first motor and a second motor, the first shaft is connected to the output shaft of the first motor via a first transmission mechanism, the second shaft is connected to the output shaft of the second motor via a second transmission mechanism, the control end of the motor is connected to the signal output end of the controller, a temperature sensor is arranged outside the housing (6), and the signal output end of the temperature sensor is connected to the signal input end of the controller.

3. A device for improving the adaptability of an air-cooled fuel cell stack to a low-temperature environment, comprising a housing (6), characterized in that: An opening is provided at one end of the shell (6), and a partition (8) is provided inside the shell (6) along the axial direction of the opening. The partition (8) divides the middle part of the inner cavity of the shell (6) into an air inlet channel (7) and an air exhaust channel (2). A battery stack (4) is provided on one side of the partition (8) and at the entrance of the air exhaust channel (2). The air inlet of the battery stack (4) is arranged opposite to the closed end of the shell (6) and is connected to the air inlet channel (7). A fan (3) is provided in the air exhaust channel (2). A baffle is provided inside the shell (6), and the baffle is located between the baffle (8) and the opening of the shell (6). A rotating shaft is fixedly connected to the baffle, and the rotating shaft is perpendicular to the axial direction of the opening of the shell (6). The rotating shaft is connected to the shell (6), and a rotating shaft rotation drive is provided between the rotating shaft and the shell (6). Mechanism; the shaft rotation drive mechanism comprises a controller and a motor, the motor and the housing (6) are fixedly arranged relative to each other, the shaft is connected to the output shaft of the motor through a transmission mechanism, the control end of the motor is connected to the signal output end of the controller, a temperature sensor is arranged outside the housing (6), and the signal output end of the temperature sensor is connected to the signal input end of the controller; a stack exhaust control valve and an exhaust pipe are arranged in the air inlet channel (7); the inner wall of the closed end of the housing (6) is an arc surface (5) or a plane, and at least one protrusion or recessed portion is arranged on the inner wall, and the baffle is composed of a large diameter baffle (10), and the diameter of the large diameter baffle (10) is larger than the diameter of the exhaust channel (2) and the diameter of the air inlet channel (7).

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