Device for mechanical conditioning of PEM stacks

Abstract

Device (1) for mechanically conditioning PEM stacks (S) each having an anode chamber and a cathode chamber, comprising - a hot water supply line (2V) providing hot water, - a cold water supply line (4V) providing cold water, - a mixed water return (8), - at least one, preferably two or more, stack receptacles (7), each suitable for receiving a PEM stack (S) to be conditioned, comprising a stack inlet (16) via which mixed water can be supplied to the anode chamber and / or the cathode chamber, and a stack outlet (17) via which the mixed water can be discharged from the anode chamber and / or the cathode chamber via the mixed water return (8), and - at least two adjustable mixing valves (6), each assigned to a stack receptacle (7), with a hot water inlet (6H) fluidically connected to the hot water supply (2V), a cold water inlet (6K) fluidically connected to the cold water supply (4V) and a mixed water outlet (6M) fluidically connected to the stack inlet (16) of the associated stack receptacle (7), via which mixed water from hot water and cold water mixed according to the setting of the respective mixing valve (6) can be provided at the stack inlet (16) of the associated stack receptacle (7).

Description

The present invention relates to a device for the mechanical conditioning of PEM stacks, each of which has an anode chamber and a cathode chamber.PEM stacks (proton exchange membrane stacks) are central components of a PEM electrolyser and serve for the electrochemical cleavage of water into hydrogen and oxygen. A PEM stack is typically composed of a multiplicity of stacked individual cells of plate-shaped components, which are arranged between two clamping plates (end plates) and are prestressed fluidically tightly against one another by means of clamping devices-for example by screws or spring packs.In the context of industrial production and quality assurance, fully assembled PEM stacks undergo what is known as mechanical conditioning. In this case, the anode chamber and the cathode chamber of the PEM stack are typically acted upon by temperature-controlled water (process water). The aim of this process is to specifically provocate setting processes in the PEM stack in order subsequently to readjust the clamping device in such a way that the desired prestress is again achieved and the operational reliability of the stack is thus ensured in the long term. At the same time, the application of water enables a tightness test of the stack under conditions close to operation.Usually, the mechanical conditioning takes place over a period of several days and requires devices which guarantee temperature control. Devices of this type for the mechanical conditioning of PEM stacks are already known from the prior art.Against this background, the object of the invention is to provide a device for the mechanical conditioning of PEM stacks which is distinguished by improved feasibility, in particular with regard to the possibility of conditioning a plurality of PEM stacks simultaneously and efficiently.This object is achieved by the device according to the invention for the mechanical conditioning of PEM stacks according to claim 1, each having an anode chamber and a cathode chamber.The device according to the invention for the mechanical conditioning of PEM stacks each having an anode chamber and a cathode chamber comprisesa hot water supply,a cold water supply,a mixed water return,at least one or a plurality, preferably two or more, stack receptacles, each suitable for receiving a PEM stack to be conditioned, comprising a stack inlet via which a mixed water can be supplied to the anode chamber and / or the cathode chamber, and a stack outlet via which the mixed water can be discharged from the anode chamber and / or the cathode chamber via the mixed water return, andat least two adjustable mixing valves each assigned to a stack receptacle, having a hot water inlet fluidically connected to the hot water inlet, a cold water inlet fluidically connected to the cold water inlet and a mixed water outlet fluidically connected to the stack inlet of the associated stack receptacle, via which mixed water of hot water and cold water mixed according to the setting of the respective mixing valve can be provided at the stack inlet of the associated stack receptacle.Through the synergistic interaction of the features according to the invention, the temperature of the mixed water, which flows through the PEM stacks accommodated in the stack receptacles, can be adjusted individually for each PEM stack in a simple and precise manner.It has been found that undesirable thermal shocks of the PEM stack can be avoided and the longevity of the PEM stack can thus be promoted if, at the beginning of the conditioning, the stack is charged with low-viscosity mixed water of, for example, 20 to 40° during a warm-up phase for a period of (in particular) approximately 30 to 90 minutes, before the mixed water temperature is raised to approximately 60 to 80° C. during the operating temperature phase of (in particular) approximately 2 to 3 days.The device according to the invention now makes it possible for each PEM stack to be able to undergo the appropriate temperature control over the entire conditioning period and for PEM stacks to also be simultaneously conditioned, which are in different conditioning phases and therefore are intended to be supplied with mixed water of different temperature control. The load on the conditioning device can thus be increased, since it is now possible to start conditioning a further stack in the warm-up phase, although the other stacks accommodated in the device are already conditioned in the operating temperature phase.Some features and aspects of the device according to the invention are explained and defined in more detail below:Mechanical conditioning of a PEM stack is understood in the present case to mean the charging of the anode chamber and / or the cathode chamber of the PEM stack with temperature-controlled water, while the anodes and / or the cathodes of the PEM stack are (in particular) not charged with electric current.In the present case, hot water and cold water are to be understood as meaning in each case water, in particular demineralized water (demineralized water), or a mixture of (demineralized) water and other liquids, such as, for example, an antifreeze agent or an alkali.Fluids include flowable media, especially fluid media. Gases and liquids.Hot water is provided via the hot water supply line at a temperature of in particular 60 to 70° C., cold water is provided via the cold water supply line at a temperature of in particular 5 to 20° C.The formulation that two components, for example the hot water feed and the hot water feed of a mixing valve, are fluidically connected to one another expresses that, under suitable operating conditions and in particular with a suitable switching of any valves, a fluid can flow from one of the two components to the other component.Each mixing valve can be supplied with hot water and with cold water and provides a mixed water at its mixed water outlet, i.e. a mixture of the hot water and the cold water, wherein the proportion of the hot water and the cold water in the mixed water can be adjusted by adjusting the mixing valve.According to a first preferred embodiment of the invention, the device comprisesat least two inlet temperature sensors, each assigned to a stack receptacle and arranged in the respective stack inlet and suitable for detecting an actual inlet temperature of the (mixed) feed stream flowing past, anda control device operatively connected to the inlet temperature sensors and the mixing valves, whereina corresponding setpoint inlet temperature of the mixed water can be stored in the control device for each stack receptacle, andthe control unit is configured to actuate the mixing valves in each case on the basis of the actual inlet temperatures detected by the inlet temperature sensors in such a way that the actual inlet temperature of the mixed water flowing through the respective stack inlet approaches the associated stored setpoint inlet temperature.In this way, each PEM stack to be conditioned can be supplied with individually temperature-controlled mixed water in a simple and reliable manner in order to enable a precise conditioning. In a very particularly advantageous manner, a time-dependent target inflow temperature profile can be stored in the control unit for each stack intake, and the control unit can be configured such that, based on the actual inflow temperatures detected by the inflow temperature sensors, the mixing valves are each controlled such that the actual inflow temperature of the mixed water flowing through the respective stack inflow approaches the associated stored target inflow temperature according to the time-dependent target inflow temperature profile.The setpoint feed temperature profile can be configured in particular such that, at the beginning of the conditioning, the stack during a warm-up phase (in particular for a period of about 30 to 90 minutes) is the setpoint feed temperature in particular 20 to 40°, before the setpoint feed temperature is subsequently raised to in particular 60 to 80° C. during an operating temperature phase of about 2 to 3 days.An approach of an actual temperature to a target temperature is to be understood as meaning that the difference between the actual and the target temperature is reduced until they only deviate from one another by a defined (relatively small) tolerance interval.The undesired propagation of contaminants in the process water circuit of the device can be prevented by the device being used.at least two inflow conductance sensors, each of which is arranged in one of the stack inlets and is suitable for detecting an actual inflow conductance, and / orat least two sequence conductance sensors, each of which is arranged in one of the stack sequences and is suitable for detecting an actual sequence conductance, andat least two controllable shut-off valves, each of which is arranged in one of the stack inlets and / or one of the stack outlets and is suitable for shutting off the flow of mixed water through the associated stack inlet and / or stack outlet, whereinthe conductance sensors and the shut-off valves are operatively connected to the control unit,the control device is suitable for receiving the actual inflow conductances and / or the actual outflow conductances and is configured to actuate the associated shut-off valve in such a way that the mixed water flow is shut off by the associated stack inflow and / or stack outflow when a (stored) maximum conductance is exceeded by one of the actual inflow conductances and / or one of the actual outflow conductances.The conductance of a water is a measure of the ability of the water to conduct electrical current. It is typically measured in micro-siemens per centimeter (μS / cm) and indicates how many dissolved ions are present in the water. These ions can be both positively charged cations and negatively charged anions. A high conductivity value in the process water of a PEM stack during the mechanical conditioning indicates the presence of dissolved ionic impurities.Since these contaminants can impair the efficiency and service life of a PEM stack, during the joint conditioning of a plurality of PEM stacks, the propagation of these contaminants from one contaminated PEM stack to the adjacent uncontaminated PEM stacks is to be prevented by shutting off the "associated shut-off valve", that is to say that shut-off valve which is associated with the stack receptacle in which the overwriting of the maximum conductance has been determined, so that the circulation of (process) water through the contaminated PEM stack is prevented.It is provided in a particularly advantageous manner that the device according to the inventiona hot water container, which is fluidically connected to the hot water supply, for supplying hot water, anda cold water container for providing cold water, which is fluidically connected to the cold water inlet, whereinthe mixed water return line is fluidically connected to the hot water container and / or the cold water container and optionallythe hot water container and / or the cold water container have a venting valve.Alternatively, it can be provided that the device has a stratified water reservoir which is fluidically connected to the hot water supply line, the cold water supply line and the mixed water return line.A stratified water store (also referred to as a stratified store) is a water store which is designed to store the water contained in the store in a temperature-stratified manner, that is to say to "layer" thermally. In this case, water layers with different temperature levels are kept as stable as possible within the storage volume in order to efficiently use the heat content and to minimize the temperature losses.Furthermore, it can be provided that the deviceat least one pump arranged in the hot water supply and / or in the cold water supply, and / ora flow heater device arranged in the hot water supply, and / ora heating device arranged in the hot water container.In this case, in particular the hot water container and the cold water container or the stratified water store are arranged geodetically below the stack outlets and / or below the stack inlets of the stack receptacles.In this way, the mixed water can flow back via the stack outlets along a gradient through the mixed water return line and / or via the stack inlets along a gradient through the hot water feed or the hot water return or the cold water feed or the cold water return.A particularly efficient conditioning device can be realized ifthe hot water supply line and a hot water return line form a hot water circuit, andthe cold water supply and a cold water return form a cold water circuit, and in particularthe device has a heat exchanger between the hot water return and the cold water supply.The mixed water volume flows through the stack receptacles can be individually adapted and regulated if the device has at least two throttle devices, which are each arranged in one of the stack inlets.In this way, identical mixed water volume flows can be made possible across all stack receptacles-despite different pressure losses and line lengths up to the individual stack receptacles. The mixing devices can be designed in such a way that they can carry over the task of the throttle devices-for example, in that the mixing devices in the hot water inlet and in the cold water inlet each have a proportional valve which permits a continuous setting between fully open and fully closed.The undesired propagation of contaminants in the process water circuit of the device can be prevented very particularly reliably if the device is designed to be closed.a hot water bypass, which fluidically connects the hot water supply line to the mixed water return line, and a hot water bypass valve, anda cold water bypass, which fluidically connects the cold water supply to the mixed water return, and has a cold water bypass valve, whereinthe bypass valves are operatively connected to the control unit, andthe control device is configured to actuate the bypass valves in such a way that hot water can be conveyed from the hot water supply line through the hot water bypass into the mixed water return line and cold water can be conveyed from the cold water supply line through the cold water bypass into the mixed water return line when the maximum conductance is exceeded by one of the actual supply conductances and / or one of the actual discharge conductances.PEM stacks to be conditioned can be mounted in the device and disassembled again in a particularly simple and reliable manner bythe stack inlets and the stack outlets each comprise a coupling plate, andthe stack receptacles have actuators which are each assigned to one of the coupling plates and are configured to move the coupling plates in each case into a pressed-on position and a lifted-off position, wherein in the pressed-on position a fluidic tight connection is produced between the respective PEM stack and the stack inlet and the stack outlet of the associated stack receptacle.In order to promote a setting of the PEM stacks to be conditioned even further during the conditioning phase, it can be provided that the coupling plates and the at least one actuator of a stack receptacle each form a clamping device, by means of which a (time-variable) clamping force can be applied to the received PEM stack.The maximum clamping force is advantageously between 10 and 30 t force equivalent, in particular between 15 and 25 t force equivalent, wherein a t force equivalent corresponds to the weight force of a metric ton mass (1000 kg) under the standard gravitational acceleration.It is also beneficial to provoking setting movements within the PEM stack to be conditioned ifthe stack inlets each have a pressure fluctuation device which is configured to apply a water pressure fluctuation to the mixed water which can be supplied via the respective stack inlet to the anode chamber and / or the cathode chamber of the associated PEM stack, andthe pressure fluctuation devices in particular each have a compression piston and a compression volume connected fluidically to the mixed water outlet of the associated mixing valve, and the size of the compression volume can be varied by means of the compression piston.The water pressure fluctuation is at least 1 bar, preferably at least 5 bar.It has been found that it can be particularly advantageous if only the cathode chamber, but not the anode chamber, is exposed to the pressure fluctuations, in particular if the PEM stacks are designed for overpressure electrolysis systems. In the case of overpressure electrolysis systems, the cathode side is under an overpressure of 20 bar or more with respect to the anode side during operation, in order to make it possible for the stack inlets to each have an anode shut-off valve which is arranged downstream of the respective pressure fluctuation device and by means of which, in the closed state, a supply (inflow) of mixed water through the stack inlet into the anode chamber of the associated PEM stack can be prevented.In this way, the water pressure fluctuation can be selectively exerted only on the cathode chamber, in order to further speed up the settling behavior in this way.The spread of contaminants in the process water of the device during conditioning can be prevented when the device is being conditioned.a water treatment device, arranged in particular in the mixed water return, for filtering impurities from the mixed water, andoptionally having a water treatment bypass.The water treatment device can be designed in particular as a mixed bed filter. The water treatment bypass allows the process water to be routed past the water treatment device.A particularly simple and thorough venting of the PEM stacks to be conditioned at the beginning of the conditioning can be realized by arranging the stack inlets geodetically below the stack outlets.The mixed water is thus conveyed "from bottom to top" through the PEM stacks. In this way, the air in the PEM stacks at the beginning of the conditioning process can be easily and thoroughly removed / expelled.The present invention enables a method for the mechanical conditioning of PEM stacks each having an anode chamber and a cathode chamber by means of an apparatus for the mechanical conditioning according to the invention, having the following steps:providing the PEM stacks to be conditioned in the device for mechanical conditioning, wherein the PEM stacks are each accommodated in a stack receptacle and a mixed water can be supplied to the anode chamber and / or the cathode chamber via a stack inlet and the mixed water can be discharged from the anode chamber and / or the cathode chamber via a stack outlet,storing setpoint inlet temperatures of the mixed water for the stack receptacles in the control unit,detecting actual inlet temperatures of the mixed water flowing through the stack receptacles by the inlet temperature sensors and transmitting the actual inlet temperatures to the control device, andcontrolling the mixing valves by the control device in each case in such a way that the actual inflow temperature of the mixed water flowing through the respective stack inflow approaches the associated stored setpoint inflow temperature.It should be expressly mentioned at this point that the above-described advantageous embodiments of the conditioning device can be used in the method.Preferably, the method further comprises the steps of:storing time-dependent setpoint inlet temperature profiles for the stack recordings in the control unit; andcontrolling the mixing valves by the control device in each case in such a way that the actual inflow temperature of the mixed water flowing through the respective stack inflow approaches the associated stored setpoint inflow temperature according to the associated time-dependent setpoint inflow temperature profile.Furthermore, it can be provided that the method comprises the following steps:storing a maximum conductance in the control device,detecting actual inflow conductances and / or actual outflow conductances of the mixed water flowing through the stack receptacles by inflow conductance sensors and / or outflow conductance sensors and transmitting the actual conductances to the control device, anddetecting an exceeding of the maximum conductance by one of the actual conductances by the control device, activating a shut-off valve by the control device in such a way that the mixed water flow is shut off by the associated stack inlet and / or stack outlet.In addition, the method can preferably comprise the following steps:storing time-variable clamping force profile profiles for the stack receptacles in the control device, andapplying clamping forces, in particular time-variable clamping forces, to the PEM stacks according to the deposited clamping force profile by means of clamping devices, and / orstoring time-variable pressure fluctuation profiles for the stack recordings in the control unit,applying water pressure fluctuations to the mixed water, which can be supplied via the stack feeds to the anode chambers and / or the cathode chambers of the PEM stacks to be conditioned, in accordance with the stored pressure fluctuation profiles by means of pressure fluctuation devices.Two exemplary embodiments of the device according to the invention are explained in more detail below with reference to the drawings. Figure shows FIG. 1 shows a schematic circuit diagram of a first exemplary embodiment of the device according to the invention, FIG. 2 shows a schematic circuit diagram of a second exemplary embodiment of the device according to the invention, and FIG. 3 shows a flow chart to illustrate a method according to the invention.The first exemplary embodiment of a device 1 according to the invention for mechanical conditioning (conditioning device) illustrated in FIG. 1 is suitable for accommodating three PEM stacks S, each having an anode chamber and a cathode chamber. However, a conditioning device according to the invention is also conceivable which can accommodate significantly more PEM stacks, for example 10 to 20.The conditioning device 1 comprises a hot water circuit 2 with a hot water container 3, a cold water circuit 4 with a cold water container 5, three mixing valves 6, three stack receptacles 7, a mixed water return 8 with a water treatment device 9 together with a water treatment bypass 10 and a control unit 11.The hot water circuit 2 has a hot water supply line 2V and a hot water return line 2R, both of which open into the hot water container 3. By means of a hot water pump 12 arranged in the hot water supply 2V, hot water can be circulated in the hot water circuit 2 and provided in the hot water supply 2V. In the hot water supply 2V, a flow heater 13 is disposed to further heat hot water flowing therethrough, and in the hot water tank 3, a heater 14 is disposed. Temperature sensors 13S are arranged upstream and downstream of the flow heater device 13 in order to detect the temperature of the water flowing past and to transmit it to the control unit 11.The cold water circuit 4 is constructed largely analogously to the hot water circuit 3 and has a cold water supply 4V, a cold water return 4R and a cold water pump 15 arranged in the cold water supply 4V.The three stack receptacles 7 are each suitable for receiving a PEM stack S to be conditioned and comprise a stack inlet 16 via which a mixed water can be supplied to the anode chamber and the cathode chamber, and a stack outlet 17 via which the mixed water can be discharged from the anode chamber and the cathode chamber.The adjustable mixing valves 6 each have a hot water inlet 6H which is fluidically connected to the hot water inlet 2V, a cold water inlet 6K which is fluidically connected to the cold water inlet 4V, and a mixed water outlet 6M which is fluidically connected to the stack inlet 16 of the associated stack receptacle 7, via which mixed water of hot water and cold water mixed according to the setting of the respective mixing valve 6 can be provided at the stack inlet 16 of the associated stack receptacle 7.Between the mixing valves 7 and the associated stack inlets 16 there are arranged in each case an inlet temperature sensor 18 and a throttle device 19.The stack inlets 16 and the stack outlets 17 each have a coupling plate 20 by means of which a fluidic tight connection to the PEM stacks S can be produced. The stack receptacles 7 each have an actuator 21, which is assigned to the coupling plate 20 of the associated stack inlet 16 and is configured to move the associated coupling plate 20 into a pressed-on position and a lifted-off position, wherein in the pressed-on position a fluidic tight connection is produced between the respective PEM stack S and the associated stack inlet 16 and the associated stack outlet 17 and in the lifted-off position the associated PEM stack S can be removed from the stack receptacle 7.The stack inlet 16, the stack outlet 17 and the actuator 21 of a stack receptacle 7 form a clamping device by means of which a clamping force that can be changed over time can be applied to the received PEM stack S.The actuator 21 may be a pneumatic or a hydraulic actuator. Other types of actuators, e.g. electric motors, are possible.The inlet temperature sensors 18 are each suitable for detecting an actual inlet temperature of the mixing water flowing past and for transmitting it to the control unit 11.The stack outlets 17 are each fluidically connected to the mixed water return 8, wherein a outlet conductance sensor 22, an outlet temperature sensor 23 and a shut-off valve 24 are each arranged between the stack outlets 17 and the mixed water return 8.In the hot water supply 2V and the cold water supply 4V, a supply conductance sensor 25 is arranged upstream of the respective pump 12, 15.The conductance sensors 22, 25 are each suitable for detecting the actual conductance of the water flowing past and for transmitting it to the control unit 11. The shut-off valves 24 are suitable for shutting off and thus preventing the flow of mixed water (mixed water flow) through the associated stack outlet 17.The mixed water return 8 is connected fluidically to the hot water container 3 and the cold water container 5.The conditioning device 1 further comprises a hot water bypass 26 fluidly connecting the hot water supply line 2V to the mixed water return line 8 and having a hot water bypass valve 27, and a cold water bypass 28 fluidly connecting the cold water supply line 4V to the mixed water return line 8 and having a cold water bypass valve 29.The mixing valves 6, the sensors 18, 22, 23, 25, the throttle devices 19, the shut-off valves 24, the bypass valves 27, 29 and the pumps 12, 15 are operatively connected to the control unit 11.In the control unit 11, a maximum conductance and time-dependent setpoint inlet temperature profiles for the individual stack receptacles 7 are stored.The control unit 11 is configured to actuate the mixing valves 6 in such a way that the actual inflow temperature of the mixed water flowing through the respective stack inflow 16 approaches the associated stored setpoint inflow temperature according to the associated time-dependent setpoint inflow temperature profile.The control unit 11 is further configured to receive the actual conductances and, if the maximum conductance is exceeded by one of the actual outflow conductances, to actuate the associated shut-off valve 24 in such a way that the mixed water flow is shut off by the associated stack outflow 17. If the maximum conductance is exceeded by one of the actual forward conductances, the control device 11 is configured to actuate the bypass valves 27, 29 in such a way that hot water is conveyed from the hot water forward 2V through the hot water bypass 27 into the mixed water return 8 and cold water is conveyed from the cold water forward 4V through the cold water bypass 28 into the mixed water return 8 in order to keep the contaminated water (process water) away from the PEM stacks S in this way.The second exemplary embodiment according to FIG. 2 differs from the first exemplary embodiment according to FIG. 1 essentially in that the device 1 has a stratified water store 30 instead of a hot water container 3 and a cold water container 5. In order to avoid repetitions, therefore, only the essential differences between the two exemplary embodiments will be discussed below. Similar or identical components are provided with identical reference numerals in both exemplary embodiments.The stratified water storage 30 is fluidically connected to the hot water supply line 2V, the hot water return line 2R, the cold water supply line 4V, the cold water return line 4R and the mixed water return line 8. In the upper region of the stratified water storage 30, a heating device 14 is arranged. In FIG. 2, a series of optional heat exchangers 31 are drawn in, with the aid of which thermal energy can be shifted between the hot water circuit and the cold water circuit or can be decoupled from the hot water circuit, the cold water circuit or the mixed water return or coupled into the latter, in order to increase the energy efficiency of the conditioning apparatus 1.The flow diagram according to FIG. 3 describes in more detail a method 100 for the mechanical conditioning of PEM stacks S each having an anode chamber and a cathode chamber by means of a device 1 according to the invention for the mechanical conditioning:First, in step 110, the PEM stacks S to be conditioned are provided in the device 1 for mechanical conditioning, wherein the PEM stacks S are each accommodated in a stack receptacle 7, and a mixed water can be supplied to the anode chamber and the cathode chamber via a stack inlet 16, and a mixed water can be discharged from the anode chamber and the cathode chamber via a stack outlet 17.According to step 120, setpoint inlet temperatures of the mixed water for the stack receptacles 7 are stored in the control unit 11 by virtue of time-dependent setpoint inlet temperature profiles for the stack receptacles 7 being stored (step 125).The conditioning of the PEM stacks S then starts by starting the pumps 12, 15 and providing hot water and cold water in the respective pre-runs 2V, 4V.According to step 130, the actual inlet temperatures of the mixed water flowing through the stack receptacles 7 are detected by the inlet temperature sensors 18 and transmitted to the control unit 11.Based thereon, in steps 140, 145, the mixing valves 6 are each controlled by the control unit 11 in parallel in such a way that the actual inflow temperature of the mixed water flowing through the respective stack inflow 16 approaches the associated stored setpoint inflow temperature according to the associated time-dependent setpoint inflow temperature profile.According to step 150, a maximum conductance which is not to be exceeded is stored in the control device 11.During the conditioning process, according to step 160, actual outflow conductances of the mixed water flowing through the stack receptacles 7 are detected by outflow conductance sensors 22 and transmitted to the control unit 11.If, according to step 170, an exceeding of the maximum conductance by one of the actual conductances is determined by the control unit 11, a shut-off valve 24 is controlled by the control unit 11 in such a way that the mixed water flow is shut off by the associated stack outlet 17.According to step 180, time-variable clamping force profile profiles for the stack holders 7 are stored in the control unit 11 and, according to step 190, time-variable clamping forces are applied to the PEM stacks according to the stored clamping force profile profiles by means of clamping devices.In addition, according to step 200, time-variable pressure fluctuation profiles for the stack receptacles 7 are stored in the control unit 11 and, according to step 210, water pressure fluctuations are applied to the mixed water, which can be supplied via the stack inlets 16 to the anode chambers and the cathode chambers of the PEM stacks to be conditioned, by means of pressure fluctuation devices according to the stored pressure fluctuation profiles.List of reference characters1 Device 2 Hot water circuit 2V Hot water supply line 2R Hot water return line 3 Hot water container 4 Cold water circuit 4R Cold water return line 4V Cold water supply line 5 Cold water container 6 Mixing valve 6H Hot water inlet line 6K Cold water inlet line 6M Mixed water outlet line 7 Stack receptacle 8 Mixed water return line 9 Water treatment device 10 Water treatment bypass line 11 Control device 12 Hot water pump 13 Flow heater device 13S Temperature sensor 14 Heating device 15 Cold water pump 16 Stack inlet line 17 Stack outlet line 18 Inlet temperature sensor 19 Throttle device 20 Coupling plate 21 Actuator 22 Outlet conductance sensor 23 Outlet temperature sensor 24 Shut-off valve 25 Inlet conductance sensor 26 Hot water bypass line 27 Hot water bypass valve 28 Cold water bypass line 29 Cold water bypass valve 30 Layer Water Storage 31 Heat Exchangers S PEM Stack

Claims

Device (1) for the mechanical conditioning of PEM stacks (S) each having an anode chamber and a cathode chamber, comprising - a hot water feed (2V) providing hot water, - a cold water feed (4V) providing cold water, - a mixed water return (8), - at least one, preferably two or more, stack receptacles (7), each suitable for receiving a PEM stack (S) to be conditioned, comprising a stack inlet (16), via which a mixed water can be supplied to the anode chamber and / or to the cathode chamber, and a stack outlet (17), via which the mixed water can be discharged from the anode chamber and / or the cathode chamber via the mixed water return (8), and - at least two, each assigned to a stack receptacle (7), Adjustable mixing valves (6) having a hot water inlet (6H) which is fluidically connected to the hot water inlet (2V), a cold water inlet (6K) which is fluidically connected to the cold water inlet (4V), and a mixed water outlet (6M) which is fluidically connected to the stack inlet (16) of the associated stack receptacle (7) and via which the mixed water of hot water and cold water mixed according to the setting of the respective mixing valve (6) can be provided at the stack inlet (16) of the associated stack receptacle (7).Device (1) according to Claim 1, comprising - at least two inlet temperature sensors (18), each assigned to a stack receptacle (7) and arranged in the respective stack inlet (16) and suitable for detecting an actual inlet temperature of the mixing water flowing past, and - a control unit (11) operatively connected to the inlet temperature sensors (18) and the mixing valves (6), wherein - an associated setpoint inlet temperature of the mixing water can be stored in the control unit (11) for each stack receptacle (7), and - the control unit (11) is configured to actuate the mixing valves (6) in each case on the basis of the actual inlet temperatures detected by the inlet temperature sensors (18), the actual inlet temperature of the mixed water flowing through the respective stack inlet (16) approaches the associated stored setpoint inlet temperature.Device (1) according to one of the preceding claims, comprising - at least two inlet conductance sensors, which are each arranged in one of the stack inlets (16) and are suitable for detecting an actual inlet conductance and / or - at least two outlet conductance sensors (22), which are each arranged in one of the stack outlets (17) and are suitable for detecting an actual outlet conductance, and - at least two controllable shut-off valves (24), which are each arranged in one of the stack inlets (16) and / or one of the stack outlets (17) and are suitable for shutting off the mixed water flow through the associated stack inlet (16) and / or stack outlet (17), wherein - the conductance sensors (22) and the shut-off valves (24) are operatively connected to the control unit (11), - the control unit (11) is suitable for receiving the actual inflow conductances and / or the actual outflow conductances and is configured to actuate the associated shut-off valve (24) in such a way that the mixed water flow is shut off by the associated stack inflow (16) and / or stack outflow (17) if a maximum conductance is exceeded by one of the actual inflow conductances and / or one of the actual outflow conductances.Device (1) according to one of the preceding claims, comprising - a hot water container (3) fluidically connected to the hot water supply (2V) for supplying hot water, and - a cold water container (5) fluidically connected to the cold water supply (4V) for supplying cold water, wherein - the mixed water return line (8) is fluidically connected to the hot water container (3) and / or the cold water container (5) and optionally - the hot water container (3) and / or the cold water container (5) have a venting valve.Device (1) according to one of the preceding claims, comprising a stratified water store (30) which is fluidically connected to the hot water supply line (2V), the cold water supply line (4V) and the mixed water return line (8).Device (1) according to one of the preceding claims, comprising - at least one pump (12, 15) arranged in the hot water supply (2V) and / or in the cold water supply (4V), and / or - a flow heater device (13) arranged in the hot water supply (2V), and / or - a heating device (14) arranged in the hot water container (3).Device (1) according to one of Claims 4 to 6, wherein the hot water container (3) and the cold water container (5) or the stratified water store (30) are arranged geodetically below the stack outlets (16) and / or below the stack inlets (17) of the stack receptacles (7).Device (1) according to one of the preceding claims, wherein - the hot water supply line (2V) and a hot water return line (2R) form a hot water circuit (2), and - the cold water supply line (4V) and a cold water return line (4R) form a cold water circuit (4), and in particular - the device (1) has a heat exchanger (30) between the hot water return line (2R) and the cold water supply line (4V).Device (1) according to one of the preceding claims, comprising at least two throttle devices (19), which are each arranged in one of the stack inlets (16).Device (1) according to one of the preceding claims, comprising - a hot water bypass (26), which fluidically connects the hot water supply (2V) to the mixed water return (8), and has a hot water bypass valve (27), and - a cold water bypass (28), which fluidically connects the cold water supply (4V) to the mixed water return (8), and has a cold water bypass valve (29), wherein - the bypass valves (27, 29) are operatively connected to the control unit (11), and - the control unit (11) is configured to actuate the bypass valves (27, 29) in such a way if the maximum conductance is exceeded by one of the actual inflow conductances and / or one of the actual outflow conductances, hot water can be conveyed from the hot water supply (2V) through the hot water bypass (26) into the mixed water return (8) and cold water from the cold water supply (4V) through the cold water bypass (28) into the mixed water return (8).Device (1) according to one of the preceding claims, wherein - the stack inlets (16) and the stack outlets (17) each comprise a coupling plate (20), and - the stack receptacles (7) have actuators (21) which are each assigned to one of the coupling plates (20) and are configured to move the coupling plates (20) in each case into a pressed-on position and a lifted-off position, wherein in the pressed-on position a fluidic tight connection is produced between the respective PEM stack (S) and the stack inlet (16) and the stack outlet of the associated stack receptacle.Device (1) according to claim 11, wherein the coupling plates (20) and the at least one actuator (21) of a stack holder (7) each form a clamping device, by means of which a clamping force, which can be changed in particular over time, can be applied to the received PEM stack (S).Device (1) according to one of the preceding claims, wherein - the stack inlets (16) each have a pressure fluctuation device which is configured to apply a water pressure fluctuation to the mixed water which can be fed via the respective stack inlet (16) to the anode chamber and / or the cathode chamber of the associated PEM stack (S), and - the pressure fluctuation devices each have, in particular, a compression piston and a compression volume which is fluidically connected to the mixed water outlet (6M) of the associated mixing valve (6), and the size of the compression volume can be varied by means of the compression piston.Device (1) according to claim 13, wherein the stack inlets (16) each have an anode shut-off valve which is arranged downstream of the respective pressure fluctuation device and by means of which, in the closed state, a supply of mixed water through the stack inlet (16) into the anode chamber of the associated PEM stack can be prevented.Device (1) according to one of the preceding claims, comprising - a water treatment device (9), which is arranged in particular in the mixed water return (8), for filtering impurities from the mixed water, and - optionally a water treatment bypass (10).Device (1) according to one of the preceding claims, wherein the stack inlets (16) are arranged geodetically below the stack outlets (17).

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