Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
  • H01M8/04082—Arrangements for control of reactant parameters, e.g. pressure or concentration
  • H01M8/04089—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
  • H01M8/04298—Processes for controlling fuel cells or fuel cell systems
  • H01M8/04694—Processes for controlling fuel cells or fuel cell systems characterised by variables to be controlled
  • H01M8/04701—Temperature
  • H01M8/04708—Temperature of fuel cell reactants
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
  • H01M8/04298—Processes for controlling fuel cells or fuel cell systems
  • H01M8/04694—Processes for controlling fuel cells or fuel cell systems characterised by variables to be controlled
  • H01M8/04746—Pressure; Flow
  • H01M8/04753—Pressure; Flow of fuel cell reactants
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
  • H01M8/04298—Processes for controlling fuel cells or fuel cell systems
  • H01M8/04694—Processes for controlling fuel cells or fuel cell systems characterised by variables to be controlled
  • H01M8/04828—Humidity; Water content
  • H01M8/04835—Humidity; Water content of fuel cell reactants
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
  • H01M8/04298—Processes for controlling fuel cells or fuel cell systems
  • H01M8/04992—Processes for controlling fuel cells or fuel cell systems characterised by the implementation of mathematical or computational algorithms, e.g. feedback control loops, fuzzy logic, neural networks or artificial intelligence
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/10—Fuel cells with solid electrolytes
  • H01M2008/1095—Fuel cells with polymeric electrolytes
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/30—Hydrogen technology
  • Y02E60/50—Fuel cells

Definitions

• the subject invention relates to a controlled gas conditioning for a reaction gas of a fuel cell and a method for controlling a gas conditioning for a fuel cell for operating the fuel cell.
• Fuel cells are seen as the energy source of the future, especially for mobile use in vehicles of any kind.
• PEMFC proton exchange membrane fuel cell
• the proton exchange membrane fuel cell (PEMFC) has emerged as one of the most promising technologies because they operate at low temperatures can offer high response times, has a high power density and can be operated emission-free (reactants only hydrogen and oxygen).
• a fuel cell uses for the anode and for the cathode depending on a reaction gas, for example, oxygen 0 2 (or air) and hydrogen H 2 , which react electrochemically to generate electricity.
• a reaction gas for example, oxygen 0 2 (or air) and hydrogen H 2 , which react electrochemically to generate electricity.
• oxygen 0 2 or air
• hydrogen H 2 which react electrochemically to generate electricity.
• a conditioning of the reaction gases is not mandatory for operation of a fuel cell.
• the big problem for the gas conditioning is that the mentioned four influencing factors are dependent on each other due to physical (eg thermodynamic) relationships and have non-linear behavior.
• This problem is often circumvented by the fact that the components of the gas conditioning and the control concept for the gas conditioning are coordinated.
• a fairly simple control based on maps, characteristics, characteristic points, etc., together with simple controllers (such as PI D controller) is sufficient for a large part.
• simple controllers such as PI D controller
• the parameters of the control are provided with correction factors as a function of the SoH. If you want to fully exploit the possibilities of a fuel cell, such a simple regulation of gas conditioning is often not sufficient.
• (high) dynamic operation is understood to mean, in particular, a rapid response of the control, ie, that the control is able to follow also rapid changes in the setpoint variables of the control with the lowest possible control deviation.
• (high) dynamic operation is understood to mean, in particular, a rapid response of the control, ie, that the control is able to follow also rapid changes in the setpoint variables of the control with the lowest possible control deviation.
• the invention is based on the fact that the highly nonlinear and coupled multivariable system resulting from the mathematical modeling of the gas conditioning unit can be decoupled and linearized by applying the Lie derivatives.
• a controller can then be designed using conventional linear control theory.
• the gas conditioning unit can be accurately modeled with respect to the influencing variables, which is a prerequisite for an accurate, rapid control of the influencing variables.
• FIG. 1 shows a test stand for a fuel cell with gas conditioning according to the invention
• FIG. 2 shows the variation of the output variables with changing input variables of the coupled multivariable system
• FIG. 3 shows a controller according to the invention with two degrees of freedom for the gas conditioning
• the invention will be explained below with reference to FIG. 1 without restriction of generality using the example of a test bench 1 for a proton exchange membrane (PEMFC) fuel cell 2.
• PEMFC proton exchange membrane
• the fuel cell 2 could also be used as an electrical supply in a machine or plant. Gas conditioning and control would then be implemented in this machine or plant. If, in the following, the operation of a fuel cell 2 is discussed, it is therefore always understood to mean the operation of the fuel cell 2 on a test bench 1 and the real operation of the fuel cell 2 in a machine or installation.
• the fuel cell 2 is constructed in the example of Figure 1 on the test bench 1 and is operated at the test stand 1.
• the fuel cell 2 comprises a cathode C which is supplied with a first reaction gas, for example oxygen, also in the form of air, and an anode A, which is supplied with a second reaction gas, for example hydrogen H 2 .
• the two reaction gases are separated from each other inside the fuel cell 2 by a polymer membrane. Between cathode C and anode A, an electrical voltage U can be tapped.
• This basic structure and function of a fuel cell 2 are well known, which is why will not be discussed further here.
• At least one reaction gas is conditioned in a gas conditioning unit 3.
• the pressure p, the relative humidity ⁇ , the temperature T and the mass flow rh of the conditioned reaction gas are set - in FIG. 1 these four influencing variables are indicated at the inlet of the cathode C.
• at least three, preferably all four, of these four influencing variables are conditioned.
• “Conditioning” here means that the value of an influencing variable is regulated to a predefined value, a setpoint variable. For example, this influencing variable can be kept constant.
• a moistening device 4 for moistening the reaction gas for adjusting a relative humidity ⁇ of the reaction gas
• a tempering 5 for temperature control of the reaction gas to adjust a temperature T of the reaction gas
• a mass flow controller 6 for controlling the mass flow rh of the reaction gas
• a pressure control device 7 for controlling the Provided pressure p of the reaction gas.
• a gas source 8 is provided for the reaction gas, which is connected to the gas conditioning unit 3 or is also arranged in the gas conditioning unit 3.
• the gas source 8 is for example a pressure accumulator with compressed, dry reaction gas, for example air.
• ambient air can also be treated as gas source 8 when using air, for example filtered, compressed, dried, etc.
• the tempering device 5 is, for example, an electrical heating and cooling device or a heat exchanger.
• a device as described in AT 516 385 A1 can also be used.
• the moistening device 4 comprises a steam generator 9, a mass flow controller 10 for the steam and a mixing chamber 11.
• a mass flow controller 10 for the water vapor and also as a mass flow controller 6 for the reaction gas, conventional, suitable, commercially available, controllable mass flow controller can be used.
• the mixing chamber 11 the water vapor is mixed with the gas originating from the gas source 8 to form the conditioned reaction gas for the fuel cell 2.
• a humidifier 4 water could be supplied to the gas from the gas source 8, for example injected.
• a pressure control device 7 a back pressure valve is used in this example, which adjusts the pressure p of the reaction gas via the controllable opening cross-section.
• the back pressure valve 7 is disposed in the gas conditioning unit 3 downstream of the fuel cell 2. This makes it possible to regulate the pressure in front of the fuel cell 2, whereby the Pressure control of any pressure losses in the other components of the gas conditioning unit 3 is unaffected.
• reaction gas is in a reaction gas line 12 which is connected to the fuel cell 2, or to the cathode C or anode A of the fuel cell 2, therefore with a certain temperature T, a certain relative humidity ⁇ , a certain pressure p and a certain mass flow.
• the moistening device 4, mass flow regulating device 6, tempering device 5 and pressure regulating device 7 can be controlled via a respective manipulated variable.
• the manipulated variables are calculated by a control unit 15, in which a controller R is implemented.
• the humidifier 4 via the mass flow controller 10 for the water vapor with the
• the mass flow of gas and water vapor from the mixing chamber 1 1 is given by the total mass m in the
• U denotes the internal energy and h the specific enthalpy of the gas (here and below marked by index G), the water vapor (here and in the following marked by index S) and the reaction gas (here and in the following without index) to the mixing chamber 1 1 and u, denotes the specific internal energy of the gas and the water vapor.
• the specific enthalpy h of a gas is known to be the product of the specific heat capacity c p at constant pressure and the temperature T of the gas.
• the latent heat r 0 is additively added.
• the internal energy u, of a gas is the product of the specific heat capacity c v at constant volumes and the temperature T of the gas.
• the latent heat r 0 is additively added. If one puts all this into the energy balance and one takes into account the mass balance one obtains the following system equation which describes the temperature dynamics of the gas conditioning unit 3.
• R denotes in a known manner the gas constant for gas (index G), water vapor (index S) or for the Reaction gas (without index).
• the volume V preferably designates not only the volume of the mixing chamber 1 1, but also the volumes of the piping in the gas conditioning unit 3.
• the pressure p and the mass flow m of the reaction gas are also significantly influenced by the back pressure valve 7, which are modeled as follows can.
• the relative humidity ⁇ is through
• pw (T) denotes the saturation partial pressure, given for example by.
• the parameters can be from Plant
• T G, o and A 0 are predetermined offset quantities.
• the non-linearity results from the system functions f (x), g (x) from the equation of state and the system function h (x) from the output equation, which are each dependent on the state vector x.
• the model of the gas conditioning unit 3 is not only non-linear, but the individual
• a controller For the coupled, non-linear, MIMO system, a controller must now be designed with which the gas conditioning unit 3 can be regulated. There are many possibilities for this, with a preferred controller design being described below.
• the first step is the nonlinear, coupled multivariable system decoupled and linearized.
• the output ie an output variable y j , is derived in time in the form, whereby
• the degree of the jth output y denotes the following notation with the Lie derivatives.
• Input v and the output variables in the output vector y of the multivariable system is decoupled and can be construed as a chain of integrators. If a new synthetic input variable Vj is integrated öj times after the time, the output variable yj of the multivariable system is obtained.
• a well-known regulator R with two degrees of freedom (Two-Degree-of-Freedom (2DoF) controller), which consists of a
• Feedforward controller FW and a Fe edback controller FB exists and is shown for example in Figure 3.
• the feedforward controller is the reference variable behavior (trajectory tracking)
• a new input value Vj of the decoupled, linear multivariable system 20 corresponds to the ö j th derivative of the output This results in the feedforward part of the controller R as derivatives of the setpoints Each setpoint of the setpoint vector
• the feedback controller FB receives in a known manner a control error vector e as a deviation between the setpoints Setpoint vector and the current actual values
• Back controller can be used to correct the error and there are sufficient methods known to determine such a controller.
• a simple feedback controller FB will be described below.
• the feedback controller FB sets to the relative degree and it will be the following
• the controller parameters of the feedback controller FB can then be set,
• desired poles are preferably placed to the left of the imaginary axis to ensure stability. In this way, the controller parameters can be determined.
• the state variables x in the gas conditioning unit 3 can be measured, preferably at each sampling instant of the control.
• the state variables x can also be estimated by an observer from the input quantities u and / or output quantities y, preferably again at each sampling instant of the control.
• the state variables x can also be calculated in a different, simple way.
• the non-linear multivariable system described above is diffe- rentially flat.
• the state variables x can be simply calculated from the time course of the setpoint variables y dmd and do not have to be measured or estimated. This is indicated in Figure 3 by the index F at the state variables x.
• the time course of the desired values for example, by the test run to be performed
• the state variables x F can thus be calculated in advance offline from the time profile of the desired values and are then available for the control
• a regulator R is designed as described above, which has a good reference variable behavior, and is stable and robust, that is essentially insensitive to disturbances. This is achieved, for example, mainly by the choice of the poles of the feedback controller FB.
• an already parameterized controller R can also be used.
• a temporal Sollierenverlauf for the output variables T, p, ⁇ , m serving as set values. This setpoint course may result from the actual operation of the fuel cell 2, may be predetermined or may be determined by a test run for testing the fuel cell 2 on a test bench.
• a trajectory along which the fuel cell 2 and the gas conditioning should be performed can be calculated, for example, in a fuel cell control unit.
• the fuel cell control unit also provides the operating points from the real operation before. Criteria for the trajectory are, for example, a rapid transition, wherein the transient course should not damage the fuel cell 2.
• the state variables x F (t) can thus be calculated in advance offline from the time profile of the setpoint variables y d m d (t). Alternatively, the state variables x F (t) can also be calculated or measured online at each sampling instant of the control (that is, at each instant at which new manipulated variables are calculated).
• the sampling time for the control is typically in the millisecond range, for example, the control is operated on a test bench 1 with 100 Hz (10 ms sampling time).
• the gas conditioning unit 3 is then acted upon by the desired time course y dmd (t), for example according to the test run.
• y dmd y dmd
• the tempering device 5 Q [0 - 9kW], adjusting range of the mass flow control device 6
• the poles of the feedback controller FB were for the outputs yj with relative
• Fig.4 left is the predetermined setpoint course shown.
• the input quantities u are shown, which are set by the controller R.
• the left-hand diagram also shows the output quantities y calculated in the simulation.
• the controller R calculates the combination of the new input variables v, which result in the input variables u, which must be set with the actuators of the gas conditioning unit 3, at each sampling instant.
• the applications of the controlled gas conditioning unit 3 for the gas conditioning of a reaction gas of a fuel cell 2 are manifold.
• the gas conditioning can in particular both on a test bench (stack or cell test stand), but also in a fuel cell system, for example in a vehicle (ship, train, plane, car, truck, bicycle, motorcycle, etc.), in a power plant (also in combined heat and power), in emergency power systems, in a handheld device, to any device in which fuel cell systems can be installed.
• the gas conditioning can thus be used both in real operation of a fuel cell in a fuel cell system, but also on a test bed for testing or developing a fuel cell.
• gas conditioning can also be used for other applications, for example for conditioning the intake air of an internal combustion engine, again in real operation or on a test bench. But it could also be used to condition gases in process technology, process engineering or medical technology. Similarly, gas conditioning could also be used in metrology to precisely condition a sample gas for accurate measurement.

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• 2016
  • 2016-07-20 AT ATA50663/2016A patent/AT518518B1/de not_active IP Right Cessation
• 2017
  • 2017-07-17 US US16/318,338 patent/US10714766B2/en not_active Expired - Fee Related
  • 2017-07-17 CN CN201780044244.1A patent/CN109690850B/zh not_active Expired - Fee Related
  • 2017-07-17 EP EP17743004.8A patent/EP3488480A1/de not_active Withdrawn
  • 2017-07-17 KR KR1020197004915A patent/KR102408594B1/ko active Active
  • 2017-07-17 JP JP2019502570A patent/JP6943943B2/ja not_active Expired - Fee Related
  • 2017-07-17 CA CA3031405A patent/CA3031405A1/en active Pending
  • 2017-07-17 WO PCT/EP2017/067999 patent/WO2018015336A1/de not_active Ceased

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