Stack arrangement for an electrochemical plant, electrochemical plant

Abstract

The invention relates to a stack arrangement (1) for an electrochemical plant, in particular an electrolysis system or a fuel cell system, comprising at least one stack (2) and a metallic lattice structure (3) surrounding the at least one stack (2), which is spaced apart on all sides from the at least one stack (2). The invention further relates to an electrochemical system, in particular an electrolysis system or a fuel cell system, with a stack arrangement according to the invention.

Description

[0001] The present invention relates to a stack arrangement for an electrochemical plant, which may in particular be an electrolysis system or a fuel cell system.

[0002] The preferred application area of ​​the invention is electrochemical systems, in particular electrolysis systems or fuel cell systems, so that the invention further relates to an electrochemical system with a stack arrangement according to the invention. State of the art

[0003] The market for equipment and technologies used to produce "green" hydrogen through electrolysis is growing rapidly and steadily. Driven by the goal of decarbonization, this growth will continue to accelerate and increase in importance in the coming years. Currently, plans are underway for large-scale, industrial-scale hydrogen production through electrolysis. The aim is to develop plants capable of operating at capacities exceeding 1 GW.

[0004] The production of hydrogen through electrolysis requires electrical energy. This energy is stored in the hydrogen and can be released again at a later time using fuel cells, or used for other purposes, for example to power a fuel cell vehicle.

[0005] The electrochemical reaction for producing hydrogen through electrolysis takes place in an electrolysis cell. The electrochemical reaction for releasing the electrical energy stored in the hydrogen occurs in a fuel cell. To increase performance, multiple electrolysis cells or fuel cells are stacked on top of each other and connected to form a so-called "stack." The stack forms the core of every electrochemical system. In addition, the electrochemical system requires other components. In the case of an electrolysis system, these can include, in particular, the following components: - Power supply equipment comprising a transformer, a converter, a rectifier, - an electrolyte circuit for supplying the stack with an electrolyte, for example with water, in particular with deionized water, wherein the electrolyte circuit may include, in addition to the necessary piping, a pump, a heat exchanger and / or an electrolyte treatment system, such as an ion exchanger, - Gas treatment equipment, such as a water separator, a dryer and / or a compressor - Control and / or regulation devices as well as - Security technology.

[0006] A fuel cell system typically comprises various subsystems that supply the stack with the reaction gases hydrogen and oxygen, as well as a coolant to dissipate the waste heat generated during operation. Each subsystem is in turn composed of several components.

[0007] During the operation of an electrochemical plant, leaks in the stack or a connected component can lead to the escape of gas, a gas mixture, and / or a liquid. If the escaping gas contains hydrogen, it can combine with the oxygen in the ambient air to form an explosive gas mixture, so the immediate vicinity of the stack is usually actively ventilated. This ventilation ensures dilution and gas exchange, thus reducing the hydrogen concentration to a minimum in the event of a gas leak. If a conductive liquid, such as water, escapes, there is a risk of a short circuit if it comes into contact with an electrically conductive surface of the stack. If water escapes in the form of water vapor, it can condense on the surface of the stack and thus also lead to a short circuit.The risk of condensation is particularly high when the ambient air temperature falls below the dew point and / or a cold start is performed, requiring the stack to warm up first. Active ventilation of the immediate surroundings of the stack further exacerbates this problem.

[0008] The present invention is concerned with minimizing the risk of a short circuit on the surface of a stack of an electrochemical plant in order to ensure safe operation of the electrochemical plant.

[0009] To solve the problem, the stack arrangement with the features of claim 1 is proposed. Advantageous embodiments of the invention are described in the dependent claims. Furthermore, an electrochemical system with a stack arrangement according to the invention is described. Disclosure of the invention

[0010] A stack arrangement for an electrochemical plant, in particular an electrolysis system or a fuel cell system, is proposed. The proposed stack arrangement comprises at least one stack and a metallic lattice structure surrounding the at least one stack, which is spaced apart on all sides from the at least one stack.

[0011] Due to the complete separation of the grid structure from the at least one stack, there is no contact between the grid structure and the at least one stack. The distance is sufficiently large to prevent contact even through condensation forming on the grid structure. This lack of contact ensures that no short circuit occurs. The grid structure thus increases the operational safety of the stack arrangement. The grid structure also serves as contact protection, further enhancing safety.

[0012] Since the metallic grid structure of the stack arrangement inherently operates at a lower temperature than the at least one stack, water vapor contained in the ambient air condenses on the grid structure and not on the surface of the at least one stack. At the same time, the spaces within the grid structure ensure sufficient ventilation and cooling of the at least one stack. The grid structure is preferably fine-meshed so that condensate can reliably form on its surface. This also increases the surface area available for condensation.

[0013] According to a preferred embodiment of the invention, the metallic lattice structure is coated, at least in certain areas, with a hydrophilic material, for example, silica gel. The hydrophilic coating increases the condensate absorption capacity of the metallic lattice structure, thus further minimizing the risk of water vapor condensing on the surface of the at least one stack. It also prevents condensate from dripping onto the metallic lattice structure. The coating with the hydrophilic material therefore contributes to drying the air surrounding the at least one stack.

[0014] Since the absorption of water by a hydrophilic material, such as silica gel, is reversible, the coating made of such a hydrophilic material can be periodically regenerated, for example, by applying heat. This periodic regeneration of the hydrophilic material ensures that its water absorption capacity is maintained. During a regeneration phase, adsorption or drying of the ambient air can be ensured using a fixed bed and / or a bed of a hydrophilic material, particularly silica gel. The effectiveness of the drying process can be monitored and, if necessary, controlled using humidity sensors.

[0015] In a further development of the invention, it is proposed that the stack arrangement comprises an enclosure that encloses a volume containing the at least one stack and the metallic lattice structure surrounding the stack. The enclosure defines a specific volume for the at least one stack and the lattice structure, so that in the event of leaks, critical hydrogen accumulations can only occur within this volume. However, these can be effectively prevented by targeted ventilation of the volume.

[0016] Preferably, the enclosure therefore includes a ventilation device for actively ventilating the volume. This active ventilation leads to gas exchange within the volume, thus reliably preventing critical accumulations of hydrogen. The ventilation device can comprise at least one fan by means of which a defined air mass flow can be supplied to the volume. The at least one fan is preferably arranged in the area of ​​an inlet and / or an outlet of the enclosure.

[0017] The active ventilation of the volume enclosed by the housing also contributes to convection cooling of the metallic grid structure. This ensures that the temperature of the metallic grid structure is lower than the temperature at the surface of the at least one stack, and that any water vapor carried by the airflow reliably condenses on the surface of the metallic grid structure and not on the surface of the at least one stack.

[0018] Advantageously, the metallic grid structure is connected to a cooling device for active cooling. The advantage of active cooling of the grid structure is that even during a cold start of the stack arrangement, it can be ensured that the temperature at the surface of the grid structure is lower than the temperature at the surface of the at least one stack. The cooling device for active cooling of the grid structure can, for example, comprise a heat exchanger, preferably through which a coolant from a cooling circuit flows.

[0019] Furthermore, it is proposed that the metallic grid structure incorporate a device for the targeted drainage of condensate. This targeted drainage prevents droplet formation and the resulting droplets from falling onto the at least one stack. For example, a device for the targeted drainage of condensate could be provided in the form of at least one guide plate.

[0020] According to a further preferred embodiment of the invention, the stack arrangement includes a collection container for collecting liquids, in particular condensate. The container can then be emptied periodically to completely remove the liquids. Preferably, the collection container is arranged below the metallic grid structure so that gravity can be used to collect the liquids in the collection container.

[0021] Furthermore, an electrochemical plant, in particular an electrolysis system or a fuel cell system, with a stack arrangement according to the invention is proposed. The stack arrangement according to the invention increases the safety during operation of the electrochemical plant.

[0022] A stack arrangement according to the invention is explained in more detail below with reference to the accompanying drawing or figure. This shows, by way of example, a schematic representation of a stack arrangement according to the invention for an electrolysis system. Detailed description of the drawing

[0023] The stack arrangement 1 according to the invention, as shown in the figure, comprises a stack 2 surrounded by a metallic lattice structure 3. The metallic lattice structure 3 maintains a distance from the stack 2 on all sides. This means that there is no contact between the metallic lattice structure 3 and the stack 2.

[0024] The stack 2 and the metallic grid structure 3 are contained within a volume 5, which is enclosed by a housing 4. The housing has an inlet 8 and an outlet 9 for an air mass flow, which is supplied to the volume 5 for ventilation by means of a ventilation device 6, comprising at least one fan 7.

[0025] Due to the principle of operation, during the operation of the stack arrangement 1, the metallic lattice structure 3 is cooler than the surface of the stack 2. Water vapor carried by the air used to ventilate volume 5 therefore condenses on the metallic lattice structure 3 and not on the surface of the stack 2. A short circuit is thus reliably prevented.

[0026] In phases where the temperature difference between the surface of the grid structure 3 and the surface of the stack 2 is not very large, for example during a cold start of the stack arrangement 1, the temperature at the surface of the grid structure 3 can be further reduced by means of convection cooling generated by the ventilation device 6. Alternatively or additionally, the grid structure 3 can be connected to a cooling device (not shown) for active cooling.

[0027] To prevent condensate that forms on the surface of the metallic lattice structure 3 from forming droplets that could fall onto the stack 2, the lattice structure 3 can be coated with a hydrophilic material, such as silica gel. The coating (not shown) increases the water absorption capacity, thus counteracting droplet formation.

Claims

[1] Stack arrangement (1) for an electrochemical plant, in particular an electrolysis system or a fuel cell system, comprising at least one stack (2) and a metallic lattice structure (3) surrounding the at least one stack (2), which is spaced apart on all sides from the at least one stack (2). [2] Stack arrangement (1) according to claim 1, characterized by , that the metallic lattice structure (3) is coated at least in some areas with a hydrophilic material, for example with silica gel. [3] Stack arrangement (1) according to claim 1 or 2, characterized by , that the stack arrangement (1) comprises an enclosure (4) which encloses a volume (5) in which the at least one stack (2) and the metallic lattice structure (3) surrounding the stack (2) are contained. [4] Stack arrangement (1) according to claim 3, characterized by, that the enclosure (4) has a ventilation device (6) for active ventilation of the volume (5), wherein the ventilation device preferably comprises at least one blower (7), which is further preferably arranged in the area of ​​an inlet (8) and / or an outlet (9) of the enclosure (4). [5] Stack arrangement (1) according to any one of the preceding claims, characterized by , that the metallic grid structure (3) is connected to a cooling device for active cooling, wherein the cooling device preferably comprises a heat exchanger which is further preferably supplied with a coolant of a cooling circuit. [6] Stack arrangement (1) according to any one of the preceding claims, characterized by , that the metallic grid structure (3) has a device for the targeted drainage of condensate, for example in the form of at least one guide plate. [7] Stack arrangement (1) according to any one of the preceding claims, characterized by, that the stack arrangement (1) has a collection container for collecting liquids, in particular condensate, wherein the collection container is preferably arranged below the metallic grid structure (3). [8] Electrochemical system, in particular electrolysis system or fuel cell system, with a stack arrangement (1) according to any of the preceding claims.

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