Conditioning method for conditioning an electrochemical cell system

Abstract

The present invention relates to a conditioning method (100) for conditioning an electrochemical cell system (203). The conditioning method (100) comprises the following method steps: - mounting (103) the electrochemical cell system (203) on a test bench (200), - connecting (105) a temperature-control circuit (209) of the electrochemical cell system (203) to a temperature-control circuit (205) of the test bench (200), - starting up (107) the electrochemical cell system (203), - operating (109) the electrochemical cell system (203) on the test bench (200) for a predefined duration at at least one predefined operating point, - shutting down, with active cooling (111), the electrochemical cell system (203), - disconnecting (112) the temperature-control circuit (209) of the electrochemical cell system (203) from the temperature-control circuit (205) of the test bench (200), - shutting down, with passive cooling (113), the electrochemical cell system (203), - removing (115) the electrochemical cell system (203) from the test bench (200), wherein, during the passive cooling of the electrochemical cell system (203), the temperature-control medium of the temperature-control circuit (205) of the test bench (200) is heated.

Description

[0001] R.415621

[0002] - 1 -

[0003] Description

[0004] title

[0005] Conditioning process for conditioning an electrochemical cell system

[0006] The presented invention relates to a conditioning method for conditioning an electrochemical cell system according to the attached claims.

[0007] State of the art

[0008] The manufacturing process for producing an electrochemical cell system is generally completed by a conditioning procedure, during which the electrochemical cell system is put into operation for the first time. For an electrochemical cell system designed as a fuel cell system, such a conditioning procedure is known, for example, from DE 10 2022 200 187 A1. Particularly in PEM (polymer electrolyte membrane) cell systems, oxide deposits and impurities originating from the manufacturing process are removed from the catalyst surfaces during this conditioning procedure.Furthermore, it is known, for example, from DE 10 2013 101 829 A1, that a cell system designed as a fuel cell system is heated to at least a predetermined operating temperature during the conditioning process, whereby the fuel cell system acquires its final chemical and physical properties, in particular with regard to the humidification of the membrane of the PEM fuel cells. Similar conditioning processes exist for other electrochemical cells, for example, for PEM electrolysis cells.

[0009] A conditioning process for an electrochemical cell system is usually time-consuming, as it takes, for example, 30 minutes. Task of continuous R.415621

[0010] - 2 -

[0011] Further developments aim to minimize the time required for the conditioning process. This reduces the manufacturing costs for the cell system.

[0012] Disclosure of the invention

[0013] The presented invention relates to a conditioning process for conditioning an electrochemical cell system. The conditioning process comprises the following steps:

[0014] - Arranging the electrochemical cell system on a test bench,

[0015] - Connecting a temperature control circuit of the electrochemical cell system with a temperature control circuit of the test bench,

[0016] - Starting up the electrochemical cell system,

[0017] - Operating the electrochemical cell system for a specified duration at at least one specified operating point on the test bench,

[0018] - Shutdown with active cooling of the electrochemical cell system,

[0019] - Separating the temperature control circuit of the electrochemical cell system from the temperature control circuit of the test bench,

[0020] - Shutdown with passive cooling of the electrochemical cell system,

[0021] - Dismantling the electrochemical cell system from the test bench. During the passive cooling of the electrochemical cell system, a temperature control medium from the test bench's temperature control circuit is heated.

[0022] By heating the temperature control medium in separate temperature control circuits, the medium is already prepared for the conditioning process of the next cell system in the production line. This can save several minutes in the entire conditioning process of each individual cell system. R.415621

[0023] - 3 -

[0024] Furthermore, the energy consumption of the conditioning process can be reduced if the temperature control medium is cooled to only 30°C to 40°C during active cooling. During passive cooling, the cell system is therefore separated from the test bench's temperature control medium; cooling then occurs passively through natural convection due to the temperature difference with the surroundings.

[0025] When the next cell system is mounted on the test bench, the temperature control medium does not need to be heated from room temperature to the target temperature, for example, approximately 80°C, but is already heated to this target temperature, so that both temperature control circuits can be connected immediately. The next cell system is therefore heated or conditioned particularly quickly thanks to the already heated temperature control medium.

[0026] By using external heat energy, i.e., heat energy provided from a heat source outside the cell system, such as a heating element of the test bench, the time required to heat the cell system and, consequently, the amount of fuel consumed for conditioning can be minimized.

[0027] Preferably, during shutdown with passive cooling, the temperature control medium of the test bench's temperature control circuit is heated to 70°C to 80°C. This ensures that the temperature control medium is already at the target temperature for the next cell system's startup.

[0028] Advantageously, the process step of actively cooling the electrochemical cell system begins above a temperature of 60°C. This means that active cooling of the cell system from approximately 75°C to approximately 60°C is already carried out during the shutdown process.

[0029] In advantageous embodiments of the conditioning process, the entire shutdown of the electrochemical cell system takes approximately 3-5 minutes, whereby the temperature control circuit of the electrochemical cell system is already separated from the temperature control circuit of the R.415621 after 1-2 minutes.

[0030] - 4 -

[0031] The test bench is separated. This means that active cooling only lasts 1-2 minutes, after which the cell system is passively cooled.

[0032] It may also be provided that when connecting the temperature control circuit of the electrochemical cell system to the temperature control circuit of the test bench, a predetermined overpressure is set in the connected circuit and reduced to a predetermined normal value after a predetermined duration.

[0033] An overpressure displaces any air remaining in the temperature control circuit of the cell system. A subsequent reduction in pressure minimizes the mechanical load on the cell system.

[0034] It may also be provided that, after the cell system has been operated for the specified duration at the specified operating point on the test bench, the temperature control medium is drained from the cell system and directed into a heat buffer for use in the next cell system.

[0035] By diverting the temperature control medium heated during the conditioning process into a heat buffer or thermally insulated buffer storage tank, thermal energy provided by the cell system during the conditioning process can be at least partially stored and used to condition further cell systems.

[0036] A particularly preferred electrochemical cell system is a fuel cell system or electrolysis cell system, especially a PEM fuel cell system or PEM electrolysis cell system. Especially in PEM cell systems, conditioning of the membrane and catalyst layers is required and determines the performance and lifetime of the cells.

[0037] Further advantages, features, and details of the invention will become apparent from the following description, in which exemplary embodiments of the invention are described in detail with reference to the drawings. (See R.415621)

[0038] - 5 - the features mentioned in the claims and in the description can each be essential to the invention individually or in any combination.

[0039] They show:

[0040] Figure 1 shows a schematic representation of a possible configuration of the presented conditioning procedure.

[0041] Figure 2 shows a schematic representation of a test rig for carrying out conditioning procedures.

[0042] Figure 1 schematically illustrates a conditioning procedure 100 for conditioning an electrochemical cell system 203 on a test bench 200.

[0043] The conditioning process 100 for an electrochemical cell system 203 comprises an assembly step 103, in which the cell system 203 is mounted on the test stand 200, a connection step 105, in which a temperature control circuit 209 of the cell system 203 is connected or fluidly coupled to a temperature control circuit 205 of the test stand 200, a start-up step 107 of the cell system 203, an operating step 109, in which the cell system 203 is operated for a predetermined duration at at least one predetermined operating point on the test stand 200, a shutdown with active cooling 111 of the cell system 203, a disconnection 112 of the temperature control circuit 209 of the electrochemical cell system 203 from the temperature control circuit 205 of the test stand 200, and a shutdown with passive cooling 113 of the electrochemical cell system 203 and a step to dismantle 115 the electrochemical cell system 203 from the test stand 200.

[0044] According to the invention, the shutdown of the electrochemical cell system 203 is divided into a first part with active cooling 111 and a second part with passive cooling 113. Between these two phases, the temperature control circuit 209 of the electrochemical cell system 203 is separated from the temperature control circuit 205 of the test bench 200. During passive cooling 113, R.415621

[0045] - 6 - The temperature control medium of the temperature control circuit 205 of the test bench 200 is heated again for the conditioning process of the next electrochemical cell system, preferably to 70°C to 80°C. This ensures that the required warm temperature of the temperature control medium – preferably 70°C to 80°C – of the temperature control circuit 205 of the test bench 200 is available very quickly for the start-up 107 of the next electrochemical cell system 203. During the active cooling 111 of the electrochemical cell system 203, the temperature of the temperature control medium of the temperature control circuit 205 of the test bench 200 is lowered, preferably to 30°C to 40°C. If the temperature control circuit 209 of the cell system 203 is connected or fluidly coupled to the temperature control circuit 205 of the test bench 200, the temperature control medium of the test bench 200 flows through the cell system 203 and heats or cools it according to the temperature differences.

[0046] Typically, before operating step 109, the electrochemical cell system 203 is powered up 107, and after operating step 109, it is powered down 111, 113. The power-up and power-down of the electrochemical cell systems 203 are usually characterized by switching the operating media on or off and increasing or decreasing the electrical voltages. During power-up 107, the electrochemical cell system 203 is heated to operating temperature (approx. 60°C to 80°C), and during power-down 111, 113, it is cooled down from this operating temperature (for example, to 40°C).

[0047] The shutdown process 111, 113 is characterized, among other things, by a complete reduction of the electrical voltages of all individual cells of the electrochemical cell system 203. This typically takes even longer than actively cooling the cell system 203 from its operating temperature (approx. 65°C to 75°C) to about 40°C. According to the invention, active cooling is no longer performed for the entire duration of the shutdown process 111, 113, but preferably only for a maximum duration of 2 minutes. Afterward, the temperature control circuit 209 of the electrochemical cell system 203 is disconnected from the temperature control circuit 205 of the test bench 200, and the further R.415621

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[0049] Shutdown of cell system 203 is now only achieved through passive cooling via free convection to the environment.

[0050] While the shutdown process involving passive cooling 113 of a newly conditioned first cell system 203 is still underway, the temperature control medium of the temperature control circuit 205 of the test rig 200 can simultaneously be heated, preferably to approximately 80°C, for a second cell system 203 that is yet to be conditioned. The temperature of the temperature control medium of the temperature control circuit 205 preferably remains between 30°C and 90°C.

[0051] Figure 2 schematically depicts a test bench 200. The test bench 200 comprises a holder 201 for holding a respective electrochemical cell system 203, a temperature control circuit 205 in which a temperature control medium circulates, an interface 207 for fluid coupling of the temperature control circuit 205 of the test bench 200 with the temperature control circuit 209 of the electrochemical cell system 203, and a computing unit 211 with an interface for communication with the cell system 203. The computing unit 211 is configured to operate the cell system 203 for a predetermined duration at a predetermined operating point of the operating step 109, as well as to control the startup 107 and shutdown 111, 113 of the cell system 203.

[0052] Interface 207 has a first valve 207a and a second valve 207b for coupling and disconnecting the temperature control circuit 205 of the test bench 200 with the temperature control circuit 209 of the electrochemical cell system 203. With separate temperature control circuits 205 and 209, the temperature control medium thus passes through a bypass to the electrochemical cell system 203 and can be heated or cooled without affecting it.

[0053] In preferred embodiments of the conditioning process, the shutdown of the electrochemical cell system 203 with active cooling 111 takes approximately 1-2 minutes, during which the cell system 203 is cooled from approximately 70°C to approximately 40°C. Afterwards, the two R.415621

[0054] - 8 -

[0055] Temperature control circuits 205 and 209 are separated from each other, i.e., the two valves 207a and 207b are closed; the temperature control circuit 205 of the test bench 200 is therefore running in bypass mode, and the temperature control medium in the temperature control circuit 205 of the test bench 200 can accordingly be heated again from approximately 30°C to approximately 80°C for the conditioning of the next cell system 203.

[0056] Meanwhile, the anode and cathode of the first cell system 203 can continue to be purged with inert gas or air without stress, for example for a period of 2-3 minutes, before the cell system 203 is removed from the test stand.

[0057] 200 is dismantled 115. The entire shutdown period 111, 113 of the cell system 203 therefore preferably lasts approximately 3-5 minutes.

Claims

R.415621 - 9 - Claims 1. Conditioning process (100) for conditioning an electrochemical cell system (203) comprising the following process steps: - Arranging (103) the electrochemical cell system (203) on a Test bench (200), - Connecting (105) a temperature control circuit (209) of the electrochemical cell system (203) to a temperature control circuit (205) of the test bench (200), - Starting up (107) the electrochemical cell system (203), - Operating (109) the electrochemical cell system (203) for a specified duration at at least one specified operating point on the test bench (200), - Shutdown with active cooling (111) of the electrochemical cell system (203), - Separation (112) of the temperature control circuit (209) of the electrochemical cell system (203) from the temperature control circuit (205) of the test bench (200), - Shutdown with passive cooling (113) of the electrochemical cell system (203), - Dismantling (115) the electrochemical cell system (203) from the test stand (200), characterized in that during the passive cooling of the electrochemical cell system (203) a temperature control medium of the temperature control circuit (205) of the test stand (200) is heated.

2. Conditioning method (100) according to claim 1 characterized in that during shutdown with passive cooling (113) the temperature control medium of the temperature control circuit (205) of the test bench (200) is heated to 70°C to 80°C. R.415621 - 10 - 3. Conditioning method (100) according to claim 1 or 2 characterized in that the active cooling (111) of the electrochemical cell system (203) begins above a temperature of 60°C 4. Conditioning method (100) according to one of the preceding claims characterized in that the shutdown (111 , 113) of the electrochemical cell system (203) takes about 3-5 minutes, wherein after 1-2 minutes the temperature control circuit (209) of the electrochemical cell system (203) is separated from the temperature control circuit (205) of the test bench (200).

5. Conditioning method (100) according to one of the preceding claims characterized in that when connecting the temperature control circuit (209) of the electrochemical cell system (203) with the temperature control circuit (205) of the test bench (200), a predetermined overpressure is set in the connected circuit and reduced to a predetermined normal value after a predetermined duration.

6. Conditioning method (100) according to one of the preceding claims characterized in that the electrochemical cell system (203) is a fuel cell system or electrolysis cell system, in particular a PEM fuel cell system or PEM electrolysis cell system.

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