A contact fuel cell stack internal temperature measuring device and method

Abstract

The application provides a contact type fuel cell stack internal temperature measuring device and method, the device comprises a high-temperature-resistant insulating flexible printed board, an electric connector welding area, a heat collection area and a thermistor; wherein the high-temperature-resistant insulating flexible printed board is divided into two parts, one side is a temperature measuring area in an E shape, one side of the temperature measuring area is welded with the thermistor, the soldering pad of each thermistor comprises two welding points, one of the welding points is connected together and grounded, and the other welding point is led to the electric connector welding area through a printed conductor to interact with an external controller; on the other side of the temperature measuring area of the high-temperature-resistant insulating flexible printed board, the back surface of the position of each thermistor is provided with a copper-coated heat collection area surface, and the areas are not affected with each other in temperature measurement; the E-shaped structure part of the temperature measuring area of the high-temperature-resistant insulating flexible printed board is located in the fuel cell stack to measure the temperature. The application can make the temperature measurement more accurate and fast, and can real-time feedback the temperature distribution of different areas in the fuel cell stack.

Description

TECHNICAL FIELD

[0001] The application relates to a contact type fuel cell stack internal temperature measuring device and method, in particular to a proton exchange membrane fuel cell internal temperature distribution online detection technology, and belongs to the fuel cell field. BACKGROUND

[0002] The proton exchange membrane fuel cell is a power generation device for directly converting chemical energy into electric energy through hydrogen-oxygen chemical reaction. At present, the quality of the power supply system accounts for a large proportion in the spacecraft, for example, the power supply accounts for 16.6% of the total satellite mass of a certain small satellite launched by China. The cost of space launch is very high, and according to the launch technology in the 1990s, the cost of launching 1 kg of equipment into space is 20,000 US dollars. The fuel cell can become one of the energy choices for lunar exploration over the moon night and deep space exploration without sunlight due to the characteristics of high specific energy / specific power and silent power generation.

[0003] The space fuel cell is mainly applied to the environment including vacuum, microgravity or zero gravity, irradiation and other factors, which is quite different from the fuel cell system on the ground. Therefore, in the actual space application, due to the difference in the internal water and gas heat management parameters of the stack, the internal temperature of the stack is easily imbalanced due to the non-uniform reaction area or local membrane dryness and water flooding, irreversible damage such as local burning of the membrane electrode occurs, and the safety, reliability and long service life of the product are affected.

[0004] At present, most of the domestic patents adopt a test board of FR4 substrate, and a thermistor is embedded in the test board to realize temperature measurement. The substrate used in this measurement method generally has poor heat conduction effect, and has a certain hysteresis for the internal temperature sensing of the stack. Meanwhile, this method is equivalent to adding an additional dummy cell, which affects the overall size and sealing performance of the stack, and it is difficult to meet the existing space mechanics conditions. SUMMARY

[0005] The technical problem to be solved by the application is to overcome the shortcomings of the prior art, and provide a contact type fuel cell stack internal temperature measuring device and method, which improves the accuracy of the reaction gas temperature and membrane electrode temperature distribution detection in the fuel cell stack, and prevents the safety risk of membrane electrode burning caused by the local reaction temperature being too high in the stack.

[0006] The technical solution of the application is a contact type fuel cell stack internal temperature measuring device and method, and the device comprises:

[0007] The high-temperature-resistant insulating flexible printed board, the electric connector welding area, the heat collection area and the thermistor; wherein:

[0008] The area of the high-temperature-resistant insulating flexible printed board is divided into two parts according to functions, one side is a temperature measuring area, and the other side is an electric connector welding area;

[0009] The high-temperature-resistant and insulating flexible printed board has a plurality of soldering pads on one side of the temperature measuring area, each thermistor is soldered on one soldering pad, each soldering pad has two soldering points, one soldering point of each soldering pad is connected together and connected to ground through a through-hole pad of the printed conductor leading to the electric connector soldering area, and the other soldering point of each soldering pad is connected to an external controller through a printed conductor leading to the electric connector soldering area, and all signals are exchanged with the external controller through the electric connector soldering area;

[0010] The other side of the high-temperature-resistant and insulating flexible printed board, i.e. the back of each thermistor, is provided with a heat collection area, the surface of which is coated with copper, and each area is independent and does not affect temperature measurement.

[0011] The temperature measuring area of the high-temperature-resistant and insulating flexible printed board is in the shape of E, the thermistors and the heat collection areas are distributed on the three branches of the E, and the temperature measuring area is located inside the battery stack for temperature measurement.

[0012] Preferably, the thickness of the high-temperature-resistant and insulating flexible printed board ranges from 12.5 μm to 50 μm.

[0013] Preferably, the material of the printed conductor on the high-temperature-resistant and insulating flexible printed board is copper, and the thickness of the copper is 35 μm ± 10 μm.

[0014] Preferably, the thickness of the copper in each heat collection area is 35 μm ± 10 μm.

[0015] Preferably, the thermistors are temperature sensing elements, and the thermistors with negative temperature coefficient are used, the size of which is not greater than the gas flow channel in the battery stack, and the temperature measuring range should be able to meet the temperature of the cold start and high-temperature reaction of the stack.

[0016] Preferably, the electric connector soldering area uses an epoxy glass cloth laminate as a substrate, is located outside the battery stack, and is connected to the controller signal, and is connected to the controller through a soldered electric connector or directly soldered conductor.

[0017] Preferably, the high-temperature-resistant and insulating flexible printed board is made of polyimide material.

[0018] Preferably, the method for measuring the temperature in the contact-type fuel cell stack using the contact-type fuel cell stack temperature measuring device is as follows: the fuel cell stack includes a stack end plate, an insulating plate, a current collecting plate, a bipolar plate and a membrane electrode, the contact-type fuel cell stack temperature measuring device is placed between the bipolar plate and the current collecting plate of the battery stack; and the above structure is sequentially pressed into a whole stack.

[0019] The front of the contact type fuel cell stack internal temperature measuring device, i.e. the hot-wire thermistor side, faces the bipolar plate, and the heat collection area of the back of the contact type fuel cell stack internal temperature measuring device is close to the current collector plate; the signal on the electric connector welding area of the contact type fuel cell stack internal temperature measuring device is connected to the controller outside the device through a wire;

[0020] The controller provides a voltage reference source for temperature measurement and analog signal acquisition; after the hot-wire thermistor of the contact type fuel cell stack internal temperature measuring device converts the temperature signal into an electric signal, the signal is transmitted to the AD converter of the controller through the electric connector welding area via printed wires, the analog signal is converted into a digital signal by the MCU of the controller, and the current real-time temperature is obtained through the conversion formula of temperature and voltage signal.

[0021] Preferably, the hot-wire thermistor of the contact type fuel cell stack internal temperature measuring device converts the temperature signal into an electric signal, specifically:

[0022] The controller provides a pull-up resistor connected to the hot-wire thermistor, a hot-wire thermistor ground wire GND, and a temperature measurement circuit voltage reference source VCC; the pull-up resistor and the hot-wire thermistor are consistent in number and are connected in series one by one, one end of each pull-up resistor is connected to the temperature measurement circuit voltage reference source VCC, the other end of each pull-up resistor is connected in series with one hot-wire thermistor, and the other end of each hot-wire thermistor is connected to the ground wire; the resistance value of the hot-wire thermistor changes according to the change of the environmental temperature, thereby forming different resistance voltage division signals, and the resistance voltage division signals are the temperature signals.

[0023] Preferably, the high-temperature-resistant insulating flexible printed board of the contact type fuel cell stack internal temperature measuring device; the size of the E-shaped temperature measurement area and the distribution of the hot-wire thermistors are designed according to the size of the battery stack and the flow channel position of the bipolar plate, so as to ensure that the hot-wire thermistors can detect the temperature of the gas in the gas flow channel, and the distribution of the hot-wire thermistors can uniformly cover the entire side surface of the battery stack.

[0024] Compared with the prior art, the present application has the following advantages:

[0025] (1) The present application is designed for direct measurement of the gas reaction temperature and the membrane electrode temperature inside the stack, rather than indirect measurement of the average temperature inside the stack by the temperature of the cooling liquid, so that the temperature measurement is more accurate and faster, and the temperature distribution in different regions inside the stack can be fed back in real time to prevent local overheating and damage to the fuel cell due to inadequate control measures;

[0026] (2) The present application increases the heat collection area on the back of the hot-wire thermistor, increases the temperature sensing area of the hot-wire thermistor, and greatly improves the accuracy of temperature detection;

[0027] (3) The application adopts high-temperature-resistant insulating material such as polyimide for design, and sensing elements such as thermistors can be embedded in the flow channel, which can be well integrated in the stack, without affecting the size and sealing of the stack, and realizing the function of long-term online temperature detection. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 It is a schematic diagram of the front side of the device, i.e. the side of the welded thermistor;

[0029] Figure 2 It is a schematic diagram of the back side of the device, i.e. the side of the heat collection area;

[0030] Figure 3 It is a schematic diagram of the installation position of the device;

[0031] Figure 4 It is a schematic diagram of the temperature measurement circuit of the device.

[0032] BRIEF DESCRIPTION OF DRAWINGS:

[0033] 1, the welding area of the electrical connector, 2, the high-temperature-resistant insulating flexible printed board, 3, the thermistor, 4, the heat collection area, 5, the end plate of the stack, 6, the insulating plate of the stack, 7, the current collecting plate of the stack, 8, the in-stack temperature measurement device, 9, the bipolar plate, 10, the membrane electrode. DETAILED DESCRIPTION

[0034] The application will be described in detail below in combination with the drawings.

[0035] The contact type fuel cell stack temperature measurement device of the application comprises: a high-temperature-resistant insulating flexible printed board 2, a thermistor 3, a heat collection area 4 and an electrical connector welding area 1; a plurality of pads for welding thermistors are placed on the high-temperature-resistant insulating flexible printed board 2, the thermistors 3 are welded to the pads, each pad for welding thermistors contains two welding points, one welding point of each pad is connected together and led to the through-hole pad of the electrical connector area through the printed conductor, and the other point of each pad is led to the electrical connector area through the printed conductor respectively, and all signals are realized through the electrical connector area 1 and the outside of the device.

[0036] The connection mode of the above structure is that the proton exchange membrane fuel cell comprises a stack end plate 5, an insulating plate 6, a current collecting plate 7, a bipolar plate 9 and a membrane electrode 10, and the structure is sequentially press-bonded into a whole stack, wherein the contact type fuel cell stack temperature measuring device of the application is placed between the bipolar plate 9 and the current collecting plate 7 of the stack, and the front side of the device, i.e. the side containing the thermistors, faces the bipolar plate 9 and is embedded in the channel of the bipolar plate 9, and the back side of the device is close to the current collecting plate 7 as the heat collection area. The signals on the electrical connector area of the device are connected to the controller outside the device through wires, and the controller mainly provides a voltage reference source for temperature measurement and analog signal acquisition. After the thermistors of the device convert the temperature signals into electrical signals, the signals are transmitted to the AD converter of the controller through the printed wires, and the analog signal is converted into a digital signal through the MCU control.

[0037] Figure 1 The front side of the contact type fuel cell stack temperature measuring device of the application is the side on which the thermistors are welded. The side comprises an electrical connector welding area 1 with FR4 as the substrate, a high-temperature-resistant insulating flexible printed board 2 and thermistors RT1-RT9.

[0038] The electrical connector welding area 1 with FR4 as the substrate is the area of the device exposed to the outside of the stack and connected to the controller signal, and is also the rigid-flexible combination area of the whole device. The electrical connector can be welded here or the wires can be directly welded and connected to the controller.

[0039] The high-temperature-resistant insulating flexible printed board 2 can be composed of high-temperature-resistant insulating materials such as polyimide, and the thickness is controlled to be 12.5 μm-50 μm, so as to facilitate the integration of the fuel cell stack without affecting the compression rate and the stack leakage rate.

[0040] The thermistors RT1-RT9 are temperature sensing elements, and negative temperature coefficient thermistors are used to prevent the system from being damaged when the resistance is short-circuited to ground. Such resistors have the characteristics of small size and wide temperature measurement range, and ERTJZEG103FA produced by Matsushita Company of Japan is selected, which is packaged as 0201, the resistance is 10K@25℃, the precision is 1%, and the height is only 0.3mm.

[0041] Figure 2 The back side of the contact type fuel cell stack temperature measuring device of the application is the side containing the heat collection area 4. The heat collection area 4 corresponds to a block area on the back side of each thermistor, and the copper thickness of the block area is 35 μm. Each block area is independent and does not affect the temperature measurement between two block areas.

[0042] Figure 3The installation position of the contact type fuel cell stack internal temperature measuring device in the electric pile is shown in the schematic view; the internal temperature measuring device of the electric pile is located between the current collecting plate and the bipolar plate in the electric pile, and the front of the contact type fuel cell stack internal temperature measuring device of the application, i.e. the side welded with the thermistor, faces the bipolar plate, the thermistor is embedded into the channel of the bipolar plate, and the back of the device is close to the current collecting plate.

[0043] Figure 4 The temperature measuring principle diagram of the contact type fuel cell stack internal temperature measuring device is shown in the figure, RT1-RT9 represent thermistors respectively, X1 is the external electrical connector area of the contact type fuel cell stack internal temperature measuring device of the application, GND is the thermistor grounding wire, the pull-up resistors R1-R9 connected with the thermistors are all provided by the controller, and the pull-up resistors are all precision resistors, VCC is the temperature measuring circuit voltage reference source, the VCC voltage signal is connected to GND through the pull-up resistors and the thermistors, forming a resistance voltage division signal, one end of each pull-up resistor is connected to the temperature measuring circuit voltage reference source VCC, and the other end corresponds to a thermistor in series, the other end of each thermistor is connected to the grounding wire, the resistance value of the thermistor changes according to the change of the environmental temperature, thereby forming different resistance voltage division signals, the voltage signal is the temperature signal, the temperature signal is connected to the AD converter of the controller through the wire and the X1 electrical connector welding area 1, the analog signal is converted into a digital signal through the MCU, and the current real-time temperature can be obtained through the conversion formula of the temperature and the voltage signal.

[0044] The shape of the contact type fuel cell stack internal temperature measuring device of the application is E-shaped, part of which is located in the electric pile for temperature measurement, and the electrical connector welding area is located outside the electric pile and connected with the controller. The size of the E-shaped structure and the distribution of the thermistors are designed according to the size of the electric pile and the flow channel position of the bipolar plate, so as to ensure that the position measured by the thermistor is the temperature of the gas and can uniformly cover the entire side surface of the electric pile. Each bipolar plate contains oxygen flow channels and hydrogen flow channels, and the device of the application can be placed between the oxygen flow channels of the bipolar plate and the current collecting plate, or between the hydrogen flow channels of the bipolar plate and the current collecting plate, or both. The real-time temperature near the inlet and outlet of the hydrogen, oxygen and water flow channels or the temperature difference between the two ends of the electric pile can be measured at the same time.

[0045] Embodiment:

[0046] A contact type fuel cell stack internal temperature measuring device, comprising: a polyimide flexible plate and a plurality of negative temperature coefficient thermistors and a heat collection area of the thermistors; all the thermistor connection lines are wired on the polyimide flexible plate, finally gathered into the contact points of the connector, and connected with the controller uniformly.

[0047] The polyimide flexible plate is in the shape of E type, and the width and size can be adjusted according to the structure of the stack body, and is used for uniformly covering the inside of the stack;

[0048] The thickness of the polyimide flexible plate is controlled to be 12.5-50 mu m, and is compressed on the back side of the cathode flow field or the anode flow field of the fuel cell to be measured during use;

[0049] Based on the above scheme, the plurality of negative temperature coefficient thermistors selects 0201 package and its smaller package, the size cannot exceed the gas flow channel, and the temperature measurement range should be able to meet the temperature of the stack cold start and high temperature reaction;

[0050] Based on the above scheme, the plurality of negative temperature coefficient thermistors should be uniformly distributed on the E-shaped polyimide flexible plate;

[0051] Based on the above scheme, the heat collection area of the thermistor is designed as a metal reinforced area on the back of the thermistor, which is used for supporting the thermistor, and the contact area with the membrane electrode is increased through the metal to reduce the contact resistance and more accurately reflect the temperature in the stack;

[0052] Based on the above scheme, the thermistor connecting line is connected to the ground at one end, and is respectively led to the contact point of the connector through the wire at the other end, and the wire is selected to be 35 mu m thick copper;

[0053] Based on the above scheme, the connector is located outside the stack, and is a reinforced area of the polyimide flexible plate, and an FR4 substrate is used as a substrate to weld a wire or an electrical connector;

[0054] Through the plurality of uniformly distributed thermistors in the stack, the controller can obtain the distribution data of the gas and the internal temperature of the fuel cell during the reaction of the fuel cell through the calculation and real-time recording of the temperature measurement circuit.

[0055] The purpose of the present application is to make up for the above-mentioned defects and provide a contact type fuel cell stack temperature measurement method, which is used for improving the accuracy of the reaction gas temperature and the membrane electrode temperature distribution detection in the fuel cell stack, improving the accuracy of the online health control strategy of the fuel cell, and preventing the safety risk of the local reaction temperature being too high caused by water flooding and other reasons in the stack.

[0056] The contents not described in detail in the specification of the present application belong to the prior art known to those skilled in the art.

Claims

1. A contact-type fuel cell stack temperature measurement device, characterized in that... include: High-temperature resistant insulating flexible printed circuit board (2), electrical connector soldering area (1), heat collection area (4), thermistor (3); wherein: The area of ​​the high-temperature resistant insulating flexible printed circuit board (2) is divided into two parts according to function: one side is the temperature measurement area, and the other side is the electrical connector soldering area (1); Multiple pads are placed on one side of the temperature measuring area of ​​the high temperature resistant insulating flexible printed circuit board (2). Each thermistor (3) is soldered on a corresponding pad. Each pad contains two solder points. One of the solder points of each pad is connected together and led to the through-hole pad of the electrical connector soldering area (1) through the printed wire and connected to the ground wire. The other solder point of each pad is connected to the electrical connector soldering area (1) through the printed wire and connected to the external controller. All signals are interacted with the external controller through the electrical connector soldering area (1). On the other side of the temperature measuring area of ​​the high-temperature resistant insulating flexible printed circuit board (2), that is, on the back of the position of each thermistor (3), there is a heat collection area. The surface of this area is copper-plated. Each area is independent and does not affect the temperature measurement between any two areas. The temperature measuring area of ​​the high-temperature resistant insulating flexible printed circuit board (2) is E-shaped, and the thermistor (3) and heat collection area (4) are distributed on the three branches of the E. The temperature measuring area is located inside the battery stack for temperature measurement.

2. The contact-type fuel cell stack temperature measurement device according to claim 1, characterized in that: The thickness of the high-temperature resistant insulating flexible printed circuit board (2) ranges from 12.5μm to 50μm.

3. The contact-type fuel cell stack temperature measurement device according to claim 1, characterized in that: The conductor material printed on the high-temperature resistant insulating flexible printed circuit board (2) is copper, with a copper thickness of 35μm±10μm.

4. The contact-type fuel cell stack temperature measurement device according to claim 1, characterized in that: The copper thickness of each heat collection zone (4) is 35 μm ± 10 μm.

5. The contact-type fuel cell stack temperature measurement device according to claim 1, characterized in that: The thermistor (3) is a temperature sensing element. It adopts a negative temperature coefficient thermistor, and its size does not exceed the gas flow channel in the battery stack. The temperature measurement range should be able to meet the temperature during cold start and high temperature reaction of the battery stack.

6. The contact-type fuel cell stack temperature measurement device according to claim 1, characterized in that: The electrical connector welding area (1) is based on an epoxy glass cloth laminate, located outside the battery stack and connected to the controller signal. It is connected to the controller by welding electrical connectors or directly welding wires.

7. The contact-type fuel cell stack temperature measurement device according to claim 1, characterized in that: The high-temperature resistant insulating flexible printed circuit board (2) is made of polyimide material.

8. A method for measuring the temperature inside a contact fuel cell stack using the contact fuel cell stack temperature measuring device according to claim 1, characterized in that... include: The fuel cell stack includes a stack end plate (5), an insulating plate (6), a current collector (7), a bipolar plate (9), and a membrane electrode (10). The contact-type fuel cell stack internal temperature measuring device is placed between the bipolar plate (9) and the current collector (7) of the fuel cell stack. The above structures are pressed together in sequence to form a whole stack. The front of the temperature measurement device inside the contact fuel cell stack, i.e. the side with the welded thermistor facing the bipolar plate (9) and embedded in the channel of the bipolar plate (9), and the heat collection area on the back of the temperature measurement device inside the contact fuel cell stack is close to the current collector (7); the signal on the welding area (1) of the electrical connector of the temperature measurement device inside the contact fuel cell stack is connected to the controller outside the device through the wire. The controller provides a voltage reference source and analog signal acquisition for temperature measurement; the thermistor of the temperature measurement device in the contact fuel cell stack converts the temperature signal into an electrical signal, which is then transmitted to the controller's AD converter through the printed wires and the electrical connector soldering area (1). The controller's MCU converts the analog signal into a digital signal, and then the current real-time temperature is obtained through the temperature and voltage signal conversion formula.

9. The method for measuring temperature inside a contact fuel cell stack according to claim 8, characterized in that: The thermistor in the contact-type fuel cell stack temperature measurement device converts the temperature signal into an electrical signal, specifically: The controller provides pull-up resistors connected to the thermistor (3), the grounding wire GND of the thermistor, and the voltage reference source VCC of the temperature measuring circuit. The number of pull-up resistors is the same as that of the thermistor (3) and they are connected in series one by one. One end of each pull-up resistor is connected to the voltage reference source VCC of the temperature measuring circuit, and the other end is connected in series with a thermistor. The other end of each thermistor is connected to the grounding wire. The resistance value of the thermistor (3) changes according to the change of ambient temperature, thereby forming different resistance voltage divider signals. The resistance voltage divider signal is the temperature signal.

10. The method for measuring temperature inside a contact fuel cell stack according to claim 8, characterized in that: The high-temperature resistant insulating flexible printed circuit board (2) of the contact fuel cell stack temperature measurement device is designed according to the size of the E-shaped temperature measurement area and the distribution of the thermistors (3) based on the size of the fuel cell stack and the flow channel position of the bipolar plate (9). It is necessary to ensure that the thermistors (3) can detect the temperature of the gas in the gas flow channel and that the distribution of the thermistors (3) can uniformly cover the entire side of the fuel cell stack.

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