Fuel cell impedance measuring device

Abstract

The embodiment of the utility model provides a fuel cell impedance measuring device, the fuel cell comprises a single cell, the impedance measuring device comprises a DC-DC converter, a shunt and a signal processing module, the DC-DC converter, the shunt and the fuel cell are connected in series, and the DC-DC converter applies current in a series loop; the shunt is provided with a first voltage acquisition module in parallel to acquire the first voltage of the shunt, the battery single piece is provided with a second voltage acquisition module in parallel to acquire the second voltage of the battery single piece, and the signal processing module receives the first voltage and the second voltage and sends the first voltage and the second voltage to the shunt. And calculating to obtain the resistance value of the single battery piece. According to the method, the voltage of the shunt and the voltage of the single cell are acquired, the impedance is calculated according to the Ohm law, and the impedance value change of the resistor element and the capacitor element in the equivalent circuit of the single fuel cell or the whole stack is acquired in real time, so that the method is relatively simple to implement, and the detection cost is reduced.

Description

Technical Field

[0001] The present application relates to the field of fuel cell detection technology, and in particular to a fuel cell impedance measurement device. Background Art

[0002] Fuel cell engines in the new energy industry have been widely adopted in recent years for applications in automobiles, ships, and stationary power sources due to their water-only emissions, zero pollution, increased range, rapid hydrogen refueling, and higher energy conversion efficiency, unlike internal combustion engines, which are not limited by the Carnot cycle. Fuel cell impedance is a key factor affecting its power generation efficiency, and measuring it can indirectly reveal its internal operating state.

[0003] Commercial AC impedance analyzers and other devices currently on the market are expensive, bulky, and have stringent operating voltage and current requirements, making them unable to meet the requirements of existing fuel cell systems and difficult to implement in large-scale on-vehicle applications. Furthermore, Hall-effect or mutual inductance current sensors are expensive, utilize the magnetic effect of coils, have complex structures, low accuracy, low current resistance, and demanding operating environments, making them unsuitable for use in fuel cell environments. Summary of the Invention

[0004] In view of this, an object of the embodiments of the present application is to provide a fuel cell impedance measurement device to solve the technical problem of high detection costs of existing measurement devices.

[0005] In a first aspect, an embodiment of the present application provides a fuel cell impedance measurement device, wherein the fuel cell includes a plurality of battery cells arranged in series, wherein the impedance measurement device includes: a DC-DC converter, a shunt and a signal processing module, the DC-DC converter, the shunt and the fuel cell are sequentially connected in series through wires to form a series circuit, and the DC-DC converter is used to apply a disturbance current in the series circuit; the shunt is arranged on one side of the negative pole of the fuel cell, and the shunt is provided with a first voltage acquisition module in parallel, and the first voltage acquisition module acquires the first voltage of the shunt, and the battery cell is provided with a second voltage acquisition module in parallel, and the second voltage acquisition module acquires the second voltage of the battery cell, and the signal processing module is used to receive the first voltage and the second voltage, and calculate the resistance value of the battery cell based on the first voltage and the second voltage.

[0006] The above-mentioned fuel cell impedance measurement device, wherein the signal processing module includes a signal receiving unit and a signal processing unit, the signal receiving unit is respectively communicated with the first voltage acquisition module and the second voltage acquisition module, and the signal receiving unit receives the first voltage and the second voltage; the first voltage acquisition unit is communicated with the signal processing unit, and the signal processing unit is used to calculate the resistance value of the battery cell based on the first voltage and the second voltage.

[0007] The above-mentioned fuel cell impedance measurement device, wherein the signal processing module also includes a control and monitoring unit, which is communicatively connected to the DC-DC converter, and is used to control the DC-DC converter to apply a disturbance current. The control and monitoring unit is also communicatively connected to the first voltage acquisition unit and the second voltage acquisition unit respectively, and is also used to control the first voltage acquisition unit and the second voltage acquisition unit to acquire corresponding voltages. The control and monitoring unit is also communicatively connected to the signal processing unit, and is used to obtain the resistance value of the battery cell.

[0008] The above-mentioned fuel cell impedance measurement device further includes a power control chip, which is used to control the on and off of the current of the first voltage acquisition unit, the second voltage acquisition unit, the signal processing unit or the control monitoring unit.

[0009] In the above-mentioned fuel cell impedance measurement device, the DC-DC converter is further used to be connected to a load, and when the power switch of the DC-DC converter is turned off, the DC-DC converter releases electrical energy to the load.

[0010] The above-mentioned fuel cell impedance measurement device, wherein the shunt includes a shunt resistor and two connecting wires, one end of each connecting wire is connected to the corresponding end of the shunt resistor by a fixed bolt, and the other end is connected to the first voltage acquisition module and the second voltage acquisition module respectively.

[0011] In the above-mentioned fuel cell impedance measurement device, each battery cell is provided with a second voltage acquisition unit in parallel, the signal receiving unit is communicatively connected with each second voltage acquisition unit to obtain the resistance value of each battery cell, and the signal processing unit is used to obtain the resistance values of all the battery cells.

[0012] In the above-mentioned fuel cell impedance measurement device, the conductive wire is one or more of a copper busbar, an aluminum busbar, and a zinc-copper alloy wire.

[0013] This application collects the voltage of the shunt and a single battery cell, calculates the impedance according to Ohm's law, and obtains the impedance value changes of the resistance and capacitance elements in the equivalent circuit of the fuel cell cell or the entire stack in real time. It can accurately predict the overall working state of the fuel cell cell or the fuel cell stack. It is relatively simple to implement and can be commercialized and installed in vehicles, thereby reducing the detection cost.

[0014] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0016] Figure 1 A first layout diagram of a fuel cell impedance measurement device provided in an embodiment of the present application is shown.

[0017] Figure 2 A second layout diagram of a fuel cell impedance measurement device provided in an embodiment of the present application is shown. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] 1. Fuel cell; 11. Battery cell; 2. DC-DC converter; 3. Shunt; 4. Wire; 5. Communication module; 6. Signal processing module; 61. Signal receiving unit; 62. Signal processing unit; 63. Control and monitoring unit; 7. Power control chip; 8. Fixing bolts; 9. Load. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of this application.

[0021] According to the operating principles and performance characteristics of fuel cells, water generated by reactions within the fuel cell stack needs to be removed by air flow. If this liquid water is not promptly removed, it can obstruct the flow path, a phenomenon known as flooding, leading to reduced stack performance. However, to improve drainage capacity, consistently using a high air flow rate can easily dry out the flow path and the surface of the proton exchange membrane, causing the membrane to dry out, which also reduces performance. Furthermore, when the system structure is unreasonable and the number of cells increases, the phenomenon of cell voltage inconsistency becomes more pronounced. Therefore, it is necessary to monitor the operating status of the fuel cell cells in real time to promptly and effectively determine whether a cell is experiencing flooding or membrane drying. Research has found that by acquiring the impedance changes of the resistor and capacitor elements in the equivalent circuit of a fuel cell cell or the entire stack in real time, it is possible to accurately predict the overall operating status of a fuel cell cell or fuel cell stack. This application collects the voltages of the current divider 3 and individual cell cells 11 and calculates the impedance according to Ohm's law. This approach is relatively simple to implement and can be commercialized and installed in vehicles, thereby reducing testing costs.

[0022] like Figure 1 As shown, the fuel cell impedance measuring device of an embodiment of the present application, the fuel cell 1 includes a plurality of battery cells 11 arranged in series, the impedance measuring device includes: a DC-DC converter 2, a shunt 3 and a signal processing module 51, the DC-DC converter 2, the shunt 3 and the fuel cell 1 are sequentially connected in series through a wire 4 to form a series circuit, the DC-DC converter 2 is used to apply an AC disturbance current in the series circuit; the shunt 3 is arranged on one side of the negative electrode of the fuel cell 1, the shunt 3 is provided with a first voltage acquisition module in parallel to collect the first voltage of the shunt 3, any one of the battery cells 11 is provided with a second voltage acquisition module in parallel to collect the second voltage of the single battery cell 11, the signal processing module 6 is used to receive the first voltage and the second voltage, and calculate the resistance value of the single battery cell 11 based on the first voltage and the second voltage.

[0023] In conjunction with the above embodiment, the fuel cell 1 is obtained by connecting multiple battery cells 11 in series. The power of the fuel cell 1 is the sum of the power of all battery cells 11. The fuel cell 1 mainly includes a complete fuel cell system including a stack system, an air system, a hydrogen system, a cooling system, and an electrical system. This system converts the chemical energy of the fuel into electrical energy, thereby providing power for vehicles, ships, power grids, etc. The impedance measurement device can detect the impedance of a single battery cell 11, or it can detect the impedance of all battery cells 11 and calculate the sum of the impedances of all battery cells 11 to obtain the impedance of the fuel cell 1.

[0024] The impedance measuring device may include a DC-DC converter 2, a shunt 3, and a signal processing module 6. The DC-DC converter 2 is a switching power supply chip that can utilize the energy storage characteristics of capacitors and inductors to perform high-frequency switching through a controllable switch (MOSFET, etc.) to store the electrical energy input by the fuel cell 1 in the capacitor (inductor). When the switch is disconnected, the electrical energy is released to the load, thereby providing electrical energy to the load 9. The output power or voltage capacity of the DC-DC converter 2 is related to the duty cycle (the ratio of the switch conduction time to the entire switch cycle) and can be used for boosting and bucking. The shunt 3 may be a resistor shunt, which is a small resistor used to measure current. It is made based on the principle that a voltage is generated across the resistor when current passes through the resistor. It has the characteristics of high precision, fast response speed, low cost, simple use, and high current resistance.

[0025] The DC-DC converter 2, shunt 3, and fuel cell 1 are sequentially connected via wires 4 to form a series circuit. The DC-DC converter 2 is adaptable to different load voltage settings and can apply a disturbing AC current signal to the busbar copper bar in the series circuit, and then to the battery cell 11 and shunt 3. The signal processing module 6 can be a CVM (cell voltage monitor), which receives and processes the voltage signals of the fuel cell 1 cell and the shunt 3. It can synchronously measure the voltages of the battery cell 11 and the shunt 3, and calculate the current based on the collected voltages, thereby obtaining the required impedance.

[0026] The signal processing module 6 may include a signal receiving unit 61, a signal processing unit 62, a first voltage acquisition module, a second voltage acquisition module, and a control and monitoring unit 63. The first voltage acquisition module is arranged in parallel with the shunt 3 and is used to acquire a first voltage across the shunt 3. The second voltage acquisition module is arranged in parallel with a battery cell 11 and is used to acquire a second voltage across the battery cell 11. The first and second voltage acquisition modules may be voltmeters or multimeters. The signal receiving unit 61 receives voltage signals from the first and second voltage acquisition modules. The signal processing unit 62 obtains the voltage signals from the first and second voltage acquisition modules and calculates the impedance of the battery cell 11 according to Ohm's law. Specifically, since the resistance of the shunt 3 is known, after obtaining the first voltage across the shunt 3, the current flowing through the shunt 3 can be obtained according to Ohm's law. Since the shunt 3 is arranged in series with each battery cell 11, the battery value flowing through the shunt 3 is recorded as the current value of the battery cell 11. After obtaining the second voltage of a single battery cell 11, the resistance value of the battery cell 11 can be obtained according to Ohm's law, and this resistance value is the impedance of the battery cell 11.

[0027] The control and monitoring unit 63 is a control and detection module for the fuel cell 1, which is communicatively connected to the signal processing unit 62, the first voltage acquisition module, the second voltage acquisition module and the DC-DC converter 2. It can not only send control instructions for detecting impedance, but also determine whether a single chip or the entire fuel cell 1 is flooded or too dry by obtaining impedance information, thereby monitoring the working status of the fuel cell.

[0028] Furthermore, the conductor 4 can be a copper busbar, an aluminum busbar, a copper-zinc alloy, or other highly conductive metal or alloy. Considering cost-effectiveness and durability, the conductor 4 in this application is preferably a copper busbar. The shunt 3 includes a shunt resistor and two connecting wires. The two ends of the shunt resistor are connected to the copper busbar via the two connecting wires, and the ends of each connecting wire are fixed to the copper busbar via fixing bolts 8.

[0029] like Figure 2 As shown, in the embodiment of the present application, the resistor of the shunt 3 is connected in series with the negative electrode of the output copper busbar of the fuel cell 1. Because the resistance of the shunt 3 is small near the negative electrode and the shunt itself, it is not exposed to the high voltage output of the fuel cell. In this way, when the voltage across the shunt is collected by connecting it to the impedance measurement device of the fuel cell 1 through a wiring harness, the internal design layout of the voltage collection channel of the shunt 3 does not need to be overly considered during the design of the impedance measurement device of the fuel cell 1. Even if the low-voltage power supply and communication module 5 of the impedance measurement unit of the fuel cell 1 are arranged close to the voltage collection module, because the collection channel directly contacts the negative voltage electrode of the fuel cell 1, there will be no voltage of hundreds of volts or even thousands of volts reaching the collection module, and there will be no risk of breakdown of the low-voltage power supply, communication module 5, and power control chip 7 of the impedance measurement unit of the fuel cell 1. This avoids the situation where the shunt 3 is placed at the high-voltage positive electrode of the fuel cell 1 without considering the voltage tolerance of the low-voltage power supply module and communication module 5 within the impedance measurement unit during system layout, resulting in the low-voltage portion of the fuel cell impedance measurement device being damaged during operation or after a period of operation, thereby disrupting normal function.

[0030] The above embodiment measures the impedance of one battery cell 11 . Alternatively, all battery cells 11 of the fuel cell 1 may be connected in parallel to the second voltage acquisition module. By acquiring the impedance of all battery cells 11 , the overall impedance of the fuel cell 1 can be obtained.

[0031] In addition, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application generally described and shown in the drawings here can be arranged and designed in various configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present application.

Claims

1. A fuel cell impedance measurement device, wherein the fuel cell comprises a plurality of battery cells arranged in series, characterized in that: The impedance measurement device includes: a DC-DC converter, a shunt and a signal processing module. The DC-DC converter, the shunt and the fuel cell are sequentially connected in series through wires to form a series circuit. The DC-DC converter is used to apply a disturbance current in the series circuit. The shunt is arranged on one side of the negative electrode of the fuel cell. The shunt is provided with a first voltage acquisition module in parallel. The first voltage acquisition module acquires a first voltage of the shunt. The battery cell is provided with a second voltage acquisition module in parallel. The second voltage acquisition module acquires a second voltage of the battery cell. The signal processing module is used to receive the first voltage and the second voltage, and calculate the resistance value of the battery cell based on the first voltage and the second voltage.

2. The fuel cell impedance measurement device according to claim 1, characterized in that: The signal processing module includes a signal receiving unit and a signal processing unit, wherein the signal receiving unit is respectively connected to the first voltage acquisition module and the second voltage acquisition module for communication, and the signal receiving unit receives the first voltage and the second voltage; The first voltage acquisition unit is in communication with the signal processing unit, and the signal processing unit is configured to calculate the resistance of the battery cell according to the first voltage and the second voltage.

3. The fuel cell impedance measurement device according to claim 2, characterized in that: The signal processing module also includes a control and monitoring unit, which is communicatively connected to the DC-DC converter and is used to control the DC-DC converter to apply a disturbance current. The control and monitoring unit is also communicatively connected to the first voltage acquisition unit and the second voltage acquisition unit, respectively, and is also used to control the first voltage acquisition unit and the second voltage acquisition unit to acquire corresponding voltages. The control and monitoring unit is also communicatively connected to the signal processing unit and is used to obtain the resistance value of the battery cell.

4. The fuel cell impedance measurement device according to claim 3, characterized in that: It also includes a power control chip, which is used to control the on and off of the current of the first voltage acquisition unit, the second voltage acquisition unit, the signal processing unit or the control monitoring unit.

5. The fuel cell impedance measurement device according to claim 2, characterized in that: The DC-DC converter is further configured to be connected to a load. When the power switch of the DC-DC converter is disconnected, the DC-DC converter releases electrical energy to the load.

6. The fuel cell impedance measurement device according to claim 5, characterized in that: The shunt includes a shunt resistor and two connecting wires, one end of each connecting wire is connected to the corresponding end of the shunt resistor through a fixed bolt, and the other end is connected to the first voltage acquisition module and the second voltage acquisition module respectively.

7. The fuel cell impedance measurement device according to claim 6, characterized in that: Each battery cell is provided with a second voltage acquisition unit in parallel, the signal receiving unit is communicatively connected with each second voltage acquisition unit to obtain the resistance value of each battery cell, and the signal processing unit is used to obtain the resistance values of all the battery cells.

8. The fuel cell impedance measurement device according to claim 4, characterized in that: The conductors are one or more of copper busbars, aluminum busbars, and zinc-copper alloy wires.

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