Electrochemical cell systems with thermal energy reservoirs and related methods

Abstract

An electrochemical cell system (100) comprising: an electrochemical cell arrangement (10); a control unit (20) configured to operate the electrochemical cell arrangement (10) only as an electrolytic cell or as a fuel cell; a heating unit (40) located outside the electrochemical cell arrangement (10), the heating unit being thermally coupled to the electrochemical cell arrangement (10) and the heating unit being configured to alternately store heat from the electrochemical cell arrangement (10) to the heating unit (40) and supply heat from the heating unit (40) to the electrochemical cell arrangement (10); and a transfer arrangement (30) configured to alternately transfer heat from the electrochemical cell arrangement (10) to the heating unit (40) and from the heating unit (40) to the electrochemical cell arrangement (10).

Description

Technical Field

[0001] The subject matter disclosed herein relates to an electrochemical cell system with a thermal energy storage and a method for transferring heat between an electrochemical cell and the thermal energy storage. Background Art

[0002] An electrochemical cell is a device capable of generating electrical energy from a chemical reaction or using electrical energy to cause a chemical reaction. Generally, electrochemical cells that process chemicals or fuels for energy purposes (i.e., fuel cells) and electrochemical cells that use energy for water splitting purposes (i.e., electrolyzers) include at least three main components, which are arranged in a layer structure, represented as two electrodes and an electrolyte located between them.

[0003] Different types of electrochemical cells are currently known and can be classified, for example, by their operating temperature (high-temperature cells, medium-temperature cells, and low-temperature cells). For example, solid oxide cells (SOCs) belong to high-temperature cells and operate in a temperature range typically from 500 °C to 1000 °C; proton conducting ceramic cells (PCCs) operate in a temperature range typically from 400 °C to 700 °C. As mentioned above, electrochemical cells can operate to generate electrical energy (i.e., as fuel cells) or can use electrical energy to cause a chemical reaction (i.e., as electrolyzers). For example, solid oxide electrolyzers use electrical energy to split water ( = W) to produce hydrogen ( = H2) and oxygen ( = O2), while solid oxide fuel cells use fuel (usually hydrogen or a fluid containing a high percentage of hydrogen) and an oxidant (usually oxygen) to generate electrical energy ( = EE) and steam (which may also be other exhaust streams).

[0004] It should be noted that electrolysis reactions are generally endothermic reactions and thus require thermal energy, while fuel cells generally operate as an exothermic process (especially exothermic reactions) and thus generate energy. However, high-temperature cells and medium-temperature cells require higher temperatures to operate compared to normal low-temperature cell conditions (e.g., above 500 °C). For example, due to their higher operating temperature, solid oxide electrolyzers can operate in three different electrolysis modes: endothermic, thermoneutral, or exothermic. However, after the cell stops operating, the temperature of the cell will decrease and may even reach room temperature. Therefore, the transient time of the cell (e.g., during startup) may be long. For example, it may take several hours to reach the operating temperature.

[0005] There are known regenerative solid oxide cells, i.e., cells that can operate reversibly as electrolyzers and fuel cells (see, e.g., patent documents US2016 / 0248137 A1, US 2013 / 112569A1, and US2004 / 081859A1). In particular, in a regenerative solid oxide cell, excess heat can be stored during the exothermic fuel cell mode, and heat can be released during the endothermic electrolysis mode to help maintain the reaction zone of the cell at the operating temperature. According to the report "Optimization & Demonstration of a Solid Oxide Regenerative Fuel Cell System" prepared for the National Energy Technology Laboratory of the US Department of Energy, it is known that heat storage inside the regenerative solid oxide cell is carried out, in particular, by using a phase change material (= PCM) integrated into the cell stack to perform heat storage inside the regenerative solid oxide cell. According to the paper "Improving Hybrid Efficiency and Flexibility by Integrating Thermal Energy Storage into the Fuel Cell System" by Tucker et al., it is known that heat storage inside the solid oxide cell is carried out, in particular, by using an interconnect material (usually stainless steel) as a heat energy storage device. The purpose of internal heat storage and exchange in the cell is to provide the heat necessary to maintain the reaction zone at the operating temperature during electrolysis, and it strongly depends on the operating state of the cell because it only operates when the cell is in the operating state (i.e., switched on). Summary of the Invention

[0006] There is a desire to have an electrochemical cell system that has a plurality of cells optimized to operate only as an electrolyzer or only as a fuel cell, and the electrochemical cell system has a faster start-up time. In particular, the electrochemical cell system can raise the temperature of the cell before the next start-up so that at the start-up, the temperature in the cell is substantially the operating temperature of the cell, thereby improving cell performance. In addition, there is a desire to have an electrochemical cell system that includes a heating unit that can operate independently of the operation of the system, i.e., can exchange heat with the cell when the cell is in the operating state (i.e., switched on) and when the cell is not in the operating state (i.e., switched off).

[0007] According to one aspect, the subject matter disclosed herein relates to a system for an electrochemical cell, the system for the electrochemical cell comprising: an electrochemical cell arrangement; a control unit configured to operate the electrochemical cell arrangement as an electrolytic cell only or as a fuel cell only; a heating unit located outside the electrochemical cell arrangement, the heating unit being thermally coupled to the electrochemical cell arrangement and the heating unit being configured to alternately store heat from the electrochemical cell arrangement in the heating unit and supply heat from the heating unit to the electrochemical cell arrangement; and a transfer arrangement configured to alternately transfer heat from the electrochemical cell arrangement to the heating unit and from the heating unit to the electrochemical cell arrangement. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] When considered in conjunction with the accompanying drawings, the disclosed embodiments of the invention and many of its attendant advantages become better understood, so that a more comprehensive understanding thereof can be readily obtained, wherein:

[0009] Figure 1 A simplified diagram showing a first general embodiment of the innovative electrochemical cell system

[0010] Figure 2 showing the operation as an electrolytic cell during the charging phase of the heating unit Figure 1 of the embodiment

[0011] Figure 3 showing the operation as a fuel cell during the charging phase of the heating unit Figure 1 of the embodiment

[0012] Figure 4 A simplified diagram showing a second embodiment of the innovative electrochemical cell system with a steam generation system during the discharge phase of the heating unit, and

[0013] Figure 5 a simplified diagram showing a third embodiment of the innovative electrochemical cell system with an external energy source during the discharge phase of the heating unit. DETAILED DESCRIPTION

[0014] According to one aspect, the subject matter disclosed herein relates to an electrochemical cell system that consumes at least electrical energy and water to generate at least hydrogen (=H2) or consumes at least a fuel containing hydrogen (=H2) and an oxidant to generate at least electrical energy when the electrochemical cell operates, and the electrochemical cell system is provided with a heat storage (outside the electrochemical cell), which is adapted to transfer heat to and from the electrochemical cell to reduce the start-up time of the cell and is thus adapted to follow variable loads, such as a renewable energy system. When the electrochemical cell operates, the heat storage can be charged (i.e., the heat storage receives and stores heat), and when the electrochemical cell does not operate, the heat storage can be discharged (i.e., the heat storage supplies heat to the electrochemical cell). Advantageously, the innovative electrochemical cell system can use the heat storage to keep the electrochemical cell at a high temperature, preferably at the operating temperature, or raise the cell temperature before the cell operates in order to reduce the start-up time of the cell. The heat transfer between the electrochemical cell and the heat storage can be carried out by conduction and / or convection and / or radiation by means of a suitable manner.

[0015] According to another aspect, the subject matter disclosed herein relates to a method for transferring heat between an electrochemical cell and a heat storage, the heat storage being located outside the electrochemical cell and being chargeable and dischargeable independently of the operating mode of the electrochemical cell.

[0016] It should be noted that for the purposes of the present disclosure, an "electrochemical cell system" is a system that includes an electrochemical cell that can process chemicals or fuels for energy purposes (i.e., a fuel cell) or use energy for water splitting purposes (i.e., an electrolyzer). In particular, as will be better explained hereinafter, when the electrochemical cell system is configured to operate as an electrolyzer, the electrochemical cell system can perform the electrolysis of water (especially steam) to produce at least hydrogen, or the electrochemical cell system can perform the co-electrolysis of CO2 and water (especially steam) to at least produce syngas containing hydrogen. For example, the electrochemical cell system can include a solid oxide cell (=SOC) or a proton conducting ceramic cell (=PCC). However, other types of cells can be used, especially high-temperature or medium-temperature cells, such as cells having an operating temperature above 100°C, preferably above 200°C.

[0017] Reference will now be made in detail to the embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. The examples and the drawings are provided in an explanatory manner of the present disclosure, and these examples and drawings should not be construed as limiting the present disclosure. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made to the present disclosure without departing from the scope or essence of the present disclosure. In the following description, like reference numerals are used for the drawings of the embodiments to indicate elements performing the same or similar functions. In addition, for the sake of clarity, some references may not be repeated in all the drawings.

[0018] Figure 1 A simplified diagram of a first embodiment of an innovative electrochemical cell system 100 is shown, hereinafter referred to as "electrochemical cell system 100" or simply "system 100". Figure 2 and Figure 3 respectively show a first embodiment of the innovative electrochemical cell system 100 operating as an electrolytic cell during the charging phase of the heating unit and a first embodiment of the innovative electrochemical cell system 100 operating as a fuel cell during the charging phase of the heating unit. The following will be with reference to Figure 4 and Figure 5 described second and third embodiments of the innovative electrochemical cell systems 200 and 300.

[0019] By way of non-limiting reference to Figure 1 , system 100 includes an electrochemical cell arrangement 10, which includes a plurality of electrochemical cells; generally, each electrochemical cell is in the form of a stack 11, and all the electrochemical cells are electrically coupled to each other. In particular, the figure shows three electrochemical stacks 11-1, 11-2 and 11-3 including a plurality of cells; however, any number of electrochemical cells and stacks can be considered. Advantageously, the electrochemical cell arrangement 10 includes medium-temperature cells or high-temperature cells; according to one possibility, the electrochemical cell arrangement 20 includes a plurality of solid oxide cells (=SOCs).

[0020] Advantageously, each cell of the electrochemical cell arrangement includes a semiconductor material in the anode and / or cathode and / or electrolyte of the cell. In particular, the anode and / or cathode and / or electrolyte can be or can include an n-type or p-type semiconductor layer.

[0021] Advantageously, the cells of the electrochemical cell arrangement are at least solid at room temperature. In particular, if solid oxide cells (=SOCs) or proton-conducting ceramic cells (=PCCs) are used, the cells of the electrochemical cell arrangement are in a solid state at both room temperature and the operating temperature.

[0022] Advantageously, the electrolyte of the electrochemical cell arrangement is ion-permeable at least at the operating temperature. For example, if a solid oxide cell (= SOC) is used, the electrolyte is permeable to the ion O - and if a proton-conducting ceramic cell (= PCC) is used, the electrolyte is permeable to the ion H + . However, as mentioned above, other types of cells can be used, in particular medium-temperature or high-temperature cells.

[0023] It should be noted that the electrochemical cell system can operate in two different modes: as an electrolytic cell or as a fuel cell. In other words, the electrochemical cell arrangement is not configured to switch between the operating mode as an electrolytic cell and the operating mode as a fuel cell, but only between the operating mode (where the electrochemical cell operates as an electrolytic cell or as a fuel cell) and the non-operating mode (where the electrochemical cell does not operate). When the electrochemical cell system operates in the electrolytic cell mode, the system consumes at least electrical energy and steam to generate at least hydrogen, and when the electrochemical cell system operates in the fuel cell mode, the system consumes at least hydrogen (or any suitable fuel containing hydrogen, such as methane) and an oxidant (such as air) to generate at least electrical energy.

[0024] System 100 also includes a control unit 20, which is configured to operate the electrochemical cell arrangement 10 only as an electrolytic cell or only as a fuel cell. As a non-limiting example, the control unit 10 can be a computer, a programmable controller, a microprocessor or a similar device. As will be better explained below, the control unit 20 can be programmed to operate the electrochemical cell arrangement 10, for example, according to a predetermined schedule and / or a predetermined operating mode. As will be better explained below, the control unit 20 can be configured to operate and possibly control other elements of the system 100.

[0025] According to one embodiment, especially when the electrochemical cell arrangement 10 operates as an electrolytic cell (e.g., see Figure 2 ), the electrochemical cell arrangement 10 is configured to receive at least electrical energy (= EE) from an external energy source, advantageously a renewable energy source such as a solar power plant or a wind power plant. Considering that, generally speaking, the generation of renewable electricity from renewable energy sources is variable and / or intermittent, for example, it can depend on the amount of sunlight at a given location and time or on the wind speed, air density and turbine characteristics (and other factors), the electrochemical cell arrangement 10 can also be configured to operate intermittently.

[0026] According to another embodiment, especially when the electrochemical cell arrangement 10 operates as a fuel cell (e.g., see Figure 3),The electrochemical cell arrangement 10 can be configured to generate electrical energy (= EE) starting at least from hydrogen or a suitable fuel containing hydrogen (e.g., methane). It is considered that, generally speaking, the electrical energy demand is not constant over time (i.e., it is intermittent and / or has a variable load profile), and the electrochemical cell arrangement 10 can also be configured to operate intermittently.

[0027] Advantageously, the control unit 20 can be programmed to control the electrochemical cell arrangement 10 according to a predetermined strategy. For example, if the electrochemical cell arrangement 10 receives electrical energy from a solar power generation device, the control unit 20 can control the operation of the electrochemical cell arrangement based on the times of sunrise and sunset: according to one example, the electrochemical cell arrangement 10 can be turned on at 8:00 and turned off at 18:00. However, since electrochemical cells typically have a high operating temperature, e.g., above 500 °C, the electrochemical cell arrangement 10 requires time to reach the operating temperature (so-called "start-up time") after being switched on, thus reducing the performance of the system.

[0028] The system 100 also includes a heating unit 40, which is located outside the electrochemical cell arrangement 10, which is thermally coupled to the electrochemical cell arrangement 10 and which is configured to alternately store heat from the electrochemical cell arrangement 10 in the heating unit 40 and supply heat from the heating unit 40 to the electrochemical cell arrangement 10. As a non-limiting example, the heating unit 40 can be a heat storage tank using a heat storage medium (e.g., molten salt, phase change material, metal mixture or the like) or a similar device for storing thermal energy. In particular, and as will be better explained below, the heating unit 40 can store heat from the electrochemical cell arrangement 10 and possibly from an external energy source (see, e.g., Figure 5 the external energy source 360 in ) and supply heat to the electrochemical cell arrangement 10 independently of the operating mode of the electrochemical cell arrangement 10 (discharge phase). In particular, in the case where the electrochemical cell arrangement 10 is operating (i.e., switched on) and in the case where the electrochemical cell arrangement 10 is not operating (i.e., switched off), the heating unit 40 can both store and supply heat, and / or in the case where the electrochemical cell arrangement 10 is operating as an electrolytic cell and in the case where the electrochemical cell arrangement 10 is operating as a fuel cell, the heating unit 40 can both store and supply heat.

[0029] According to one possibility, when the electrochemical cell arrangement 10 is operating, for example, with non-limiting reference to the previous example, between 8:00 and 18:00, in particular during the entire operating time or during one or more time intervals of the operating time, the heating unit 40 can store heat. According to one possibility, when the electrochemical cell arrangement 10 is not operating, for example, with non-limiting reference to the previous example, between 18:00 and 8:00, the heating unit 40 can supply heat to the electrochemical cell arrangement 10. Advantageously, the heating unit 40 is configured to supply heat to the electrochemical cell arrangement 10 just before activating the electrochemical cell arrangement 10, for example from 6:00 to 8:00, or generally speaking, during a suitable time interval, in order to heat the electrochemical cell arrangement 10 so as to reach the operating temperature of the electrochemical cell at the activation time.

[0030] Advantageously, the control unit 20 is further configured to control the operation of the heating unit 40. In particular, the control unit 20 can be configured to control the heat stored in the heating unit 40, for example the charge / discharge state of the heating unit 40. Advantageously, the heating unit 40 is arranged around the electrochemical cell arrangement 10. More advantageously, the electrochemical cell system further includes an insulating housing that is arranged around the heating unit 40.

[0031] The electrochemical cell system 100 further includes a transfer arrangement 30 that is configured to alternately transfer heat from the electrochemical cell arrangement 10 to the heating unit 40 and from the heating unit 40 to the electrochemical cell arrangement 10. As will be better explained hereinafter, the transfer arrangement 30 is configured to transfer heat by conduction and / or convection and / or radiation. Advantageously, the control unit 20 is further configured to operate the transfer arrangement 30 so as to alternately activate and deactivate the transfer arrangement 30. In particular, when the transfer arrangement 30 is activated, heat transfer between the heating unit 40 and the electrochemical cell arrangement 30 is allowed; in other words, when the transfer arrangement 30 is activated, the heating unit 40 can store energy from the electrochemical cell arrangement 30 or supply energy to the electrochemical cell arrangement.

[0032] To transfer heat by conduction, the transfer arrangement 30 advantageously includes a solid device that is mechanically coupled to the electrochemical cell arrangement 10 and the heating unit 40, and the solid device is configured to transfer heat by conduction between the electrochemical cell arrangement 10 and the heating unit 40. According to one possibility, the electrochemistry can be in the form of one or more rods or plates; advantageously, the solid device is a plurality of rods or plates. When a charge / discharge phase of the heating unit 40 is required, the solid device is in contact with the electrochemical cell arrangement 10, particularly may be located between each electrochemical cell, so as to transfer heat between the heating unit 40 and the electrochemical cell arrangement 10. Alternatively, when heat exchange between the heating unit 40 and the electrochemical cell arrangement 10 is not required, the solid device is moved away in a manner that avoids contact with the electrochemical cell arrangement 10 and heat exchange. Advantageously, the control unit 20 can adjust the position of the solid device. More advantageously, the position of each rod or plate can be adjusted independently to allow for a finer adjustment of the heat transferred between the heating unit 40 and the electrochemical cell arrangement 10.

[0033] To transfer heat by convection, the transfer arrangement 30 advantageously includes a fluid circuit that is configured to circulate a fluid between the electrochemical cell arrangement 10 and the heating unit 40 and transfer heat between the electrochemical cell arrangement 10 and the heating unit 40 by convection. According to one possibility, the fluid is an inert gas (e.g., nitrogen or carbon dioxide or argon) or a molten salt or a phase change material (=PCM) or a liquid metal. Advantageously, the fluid circuit also includes a mechanical operator (e.g., a fan or a pump) and may also include a control valve to adjust the amount of fluid circulating in the fluid circuit.

[0034] To transfer heat by radiation, the transfer arrangement 30 advantageously includes an emission / absorption layer that is arranged around the electrochemical cell arrangement 10 and is configured to selectively transfer heat between the electrochemical cell arrangement 10 and the heating unit 40 by radiation (which can be emitted or absorbed). It should be noted that the emission / absorption layer can receive heat from the electrochemical cell arrangement 10 and supply it to the heating unit 40 (i.e., it operates as an emission layer during the charging phase of the heating unit 40) and can receive heat from the storage heating unit 40 and supply it to the electrochemical cell arrangement 10 (i.e., it operates as an absorption layer during the discharge phase of the heating unit 40). According to one possibility, the transfer arrangement 30 further includes an insulating layer (or a reflective layer) to adjust the heat transferred between the heating unit 40 and the electrochemical cell arrangement 10. Advantageously, the control unit 20 can adjust the position of the insulating layer such that when the insulating layer is completely or partially located between the heating unit 40 and the electrochemical cell arrangement 10, the heat exchange between them completely or partially stops.

[0035] As described above, the electrochemical cell arrangement 10 can operate as an electrolytic cell or a fuel cell. In Figure 2 , an electrochemical cell system 100 is shown when operating as an electrolytic cell, particularly during the charging phase of the heating unit 40. The electrochemical cell arrangement 10 has at least two inlets and two outlets; in particular, the electrochemical cell arrangement 10 is configured to receive at least electrical energy EE (preferably electrical energy from a renewable energy source) at a first inlet and steam S at a second inlet as inputs. The electrochemical cell arrangement 10 is configured to supply at least oxygen O2 at a first outlet and hydrogen H2 at a second outlet as outputs. According to another possibility (not shown in any figure), the electrochemical cell arrangement 10 is also configured to receive carbon dioxide CO2 at a third inlet and supply syngas containing hydrogen at the second outlet as an output. It should be noted that other flue gases may be generated by the electrochemical cell arrangement 10, which depends, for example, on the purity of the inlet streams.

[0036] In Figure 3 , an electrochemical cell system 100 is shown when operating as a fuel cell, particularly during the charging phase of the heating unit 40. The electrochemical cell arrangement 10 has at least two inlets and two outlets; in particular, the electrochemical cell arrangement 10 is configured to receive at least oxygen O2 or air (particularly ambient air) at a first inlet and hydrogen H2 or a suitable fuel containing hydrogen at a second inlet as inputs. It should be noted that the hydrogen H2 provided at the second inlet can be pure hydrogen (or substantially pure, e.g., having a purity of 95% or higher) or can be mixed with other substances (particularly carbon (e.g., which can be provided in the form of a hydrocarbon fuel (e.g., methane))). The electrochemical cell arrangement 10 is configured to supply at least electrical energy EE at a first outlet and steam S at a second outlet as outputs. It should be noted that other flue gases may be generated by the electrochemical cell arrangement 10, which depends, for example, on the purity of the hydrogen and / or on the oxidant (oxygen or air) used.

[0037] A second embodiment 200 of the electrochemical cell system will be described below with the aid of Figure 4 . It should be noted that Figure 4 The elements 210, 211, 220, 230, and 240 in Figure 1 can be the same as or similar to the elements 10 (electrochemical cell arrangement), 11 (electrochemical cell stack), 20 (control unit), 30 (transfer arrangement), and 40 (heating unit) in Figure 4 , and perform the same or similar functions. It should also be noted that Figure 4 The electrochemical cell system 200 is shown operating as an electrolytic cell, particularly during the discharging phase of the heating unit 240, as will be apparent from the following.

[0038] By way of non - limiting reference Figure 4 , the electrochemical cell system 100 may further include a steam generation system 250, which is configured to receive water W as an input and generate steam S as an output. In particular, the steam generation system 250 is thermally coupled to the heating unit 240 such that the heating unit 240 can supply heat to the steam generation system 250 to generate steam S.

[0039] Advantageously, the control unit 220 is further configured to control the operation of the steam generation system 250. In particular, the control unit 220 may be configured to control the heat transferred from the heating unit 240 to the steam generation system 250, for example, to control the amount of steam S generated by the steam generation system 250.

[0040] The third embodiment 300 of the electrochemical cell system will be described hereinafter by means of Figure 5 . It should be noted that Figure 5 the elements 310, 311, 320, 330 and 340 in Figure 1 may be the same as or similar to the elements 10 (electrochemical cell arrangement), 11 (electrochemical cell stack), 20 (control unit), 30 (transfer arrangement) and 40 (heating unit) in Figure 5 , and perform the same or similar functions. It should also be noted that

[0041] By way of non - limiting reference Figure 5 , the electrochemical cell arrangement 310 is configured to receive a pre - heated input, in particular fuel and oxidant (e.g., hydrogen and oxygen) at a temperature far above ambient temperature. According to one possibility, the steam S generated by the electrochemical cell arrangement 310 as an output is still at a high temperature, and its heat can be used to pre - heat the input of the electrochemical cell arrangement 310. In particular, the flow of steam S can supply heat to the fuel and oxidant used as the input of the electrochemical cell arrangement 310; for example, the electrochemical cell system 300 may include a dedicated heat exchanger 355 in which heat exchange occurs between steam S and the input (in particular hydrogen H2 (or a suitable fuel containing hydrogen) and oxygen O2). It should be noted that the heat exchanger 355 may be located outside the electrochemical cell arrangement 310 or integrated into the electrochemical cell arrangement. It should also be noted that after the heat exchange, the steam S at the outlet of the heat exchanger 355 may be low - temperature steam S or a mixture of steam S and water W or liquid water W.

[0042] Alternatively or in addition, the heating unit 340 may further provide heat to preheat the input received by the electrochemical cell arrangement 310. In particular, the heating unit 340 may be thermally coupled to the fuel and oxidant that serve as the input of the electrochemical cell arrangement 310; for example, the heating unit may supply heat to a dedicated heat exchanger 355 in which heat exchange occurs.

[0043] By non-limiting reference Figure 5 , the electrochemical cell arrangement 310 further includes an external energy source 360 that is thermally coupled to the heating unit 340, in particular a waste heat source and / or a renewable energy source. Advantageously, the external energy source 360 is configured to generate heat and, in particular, to supply heat to the heating unit 340. Advantageously, the heating unit 340 is configured to store the heat received from the external energy source.

[0044] According to another aspect, the subject matter disclosed herein relates to a method of transferring heat between an electrochemical cell arrangement 10 and a heating unit 40, the electrochemical cell arrangement including a plurality of electrochemical cells, the heating unit being located outside the electrochemical cells. The method includes the following steps:

[0045] - During the charging phase of the heating unit 40, storing heat from the electrochemical cell arrangement 10 in the heating unit 40,

[0046] - During the discharging phase of the heating unit 40, supplying heat from the heating unit 40 to the electrochemical cell arrangement 10, and

[0047] - Controlling the operation of the electrochemical cell arrangement 10 by a control unit 20, the control unit 20 causing the electrochemical cell arrangement 10 to switch between an operating mode and a non-operating mode.

[0048] It should be noted that the operating mode of the electrochemical cell arrangement 10 is only as an electrolytic cell or only as a fuel cell; in other words, the electrochemical cell arrangement 10 is not configured to switch between an operating mode as an electrolytic cell and an operating mode as a fuel cell, but only between an operating mode (wherein the electrochemical cell operates as an electrolytic cell or as a fuel cell) and a non-operating mode (wherein the electrochemical cell does not operate).

[0049] It should also be noted that the charging phase and the discharging phase of the heating unit 40 are performed independently of the operating mode of the electrochemical cell arrangement 10. In particular, the heating unit 40 can be charged and discharged both when the electrochemical cell arrangement 10 operates as an electrolytic cell and when the electrochemical cell operates as a fuel cell and / or when the electrochemical cell arrangement 10 is operating and when the electrochemical cell arrangement 10 is not operating.

[0050] It should also be noted that the step of storing heat and the step of supplying heat are carried out by conduction and / or convection and / or radiation. Advantageously, the step of storing heat and the step of supplying heat are carried out by a transfer arrangement 30 which is configured to alternately transfer heat (by conduction and / or convection and / or radiation) from the electrochemical cell arrangement 10 to the heating unit 40 and from the heating unit 40 to the electrochemical cell arrangement 10. It should be noted that the heating unit 40 can also store heat from an external heat source (for example, from a waste heat source or a renewable energy source).

Claims

1. An electrochemical cell system (100, 200, 300), the electrochemical cell system comprising: - An electrochemical cell arrangement (10, 210, 310), the electrochemical cell arrangement comprising a plurality of cells, - A control unit (20, 220, 320), the control unit being configured to operate the electrochemical cell arrangement (10, 210, 310) either only as an electrolytic cell or only as a fuel cell, - A heating unit (40), the heating unit being thermally coupled to the electrochemical cell arrangement (10, 210, 310) and the heating unit being configured to alternately store heat from the electrochemical cell arrangement (10, 210, 310) in the heating unit (40, 240, 340) and supply heat from the heating unit (40, 240, 340) to the electrochemical cell arrangement (10, 210, 310), and - A transfer arrangement (30, 230, 330), the transfer arrangement being configured to alternately transfer heat from the electrochemical cell arrangement (10, 210, 310) to the heating unit (40, 240, 340) and from the heating unit (40, 240, 340) to the electrochemical cell arrangement (10, 210, 310), wherein the heating unit (40, 240, 340) is located outside the electrochemical cell arrangement (10, 210, 310), wherein the transfer arrangement (30, 230, 330) is configured to transfer heat by conduction and / or convection and / or radiation.

2. The electrochemical cell system (100, 200, 300) according to claim 1, wherein each cell of the electrochemical cell arrangement (10, 210, 310) comprises a semiconductor material, the semiconductor material being located in the anode and / or cathode and / or electrolyte of the cell.

3. The electrochemical cell system (100, 200, 300) according to claim 1, wherein the cells of the electrochemical cell arrangement (10, 210, 310) are at least in a solid state at room temperature.

4. The electrochemical cell system (100, 200, 300) according to claim 2, wherein the electrolyte of the electrochemical cell arrangement (10, 210, 310) is at least ion-permeable at the cell operating temperature.

5. The electrochemical cell system (100, 200, 300) according to claim 1, wherein the control unit (20, 220, 320) is further configured to operate the transfer arrangement (30, 230, 330) so as to alternately turn on and off the transfer arrangement (30, 230, 330).

6. The electrochemical cell system (100, 200, 300) according to claim 1, wherein the heating unit (40, 240, 340) is arranged around the electrochemical cell arrangement (10, 210, 310).

7. The electrochemical cell system (100, 200, 300) according to claim 1, wherein the electrochemical cell system further comprises an insulating housing, and the insulating housing is arranged to surround the heating unit (40, 240, 340).

8. The electrochemical cell system (100, 200, 300) according to claim 1, wherein the transfer arrangement (30, 230, 330) comprises a solid device, the solid device being mechanically coupled to the electrochemical cell arrangement (10, 210, 310) and the heating unit (40, 240, 340), and the solid device being configured to transfer heat by conduction between the electrochemical cell arrangement (10, 210, 310) and the heating unit (40, 240, 340).

9. The electrochemical cell system (100, 200, 300) according to claim 1, wherein the transfer arrangement (30, 230, 330) comprises a fluid circuit, the fluid circuit being configured to circulate a fluid between the electrochemical cell arrangement (10, 210, 310) and the heating unit (40, 240, 340), and the fluid circuit being configured to transfer heat by convection between the electrochemical cell arrangement (10, 210, 310) and the heating unit (40, 240, 340).

10. The electrochemical cell system (100, 200, 300) according to claim 9, wherein the fluid is an inert gas or a molten salt or a phase change material or a liquid metal.

11. The electrochemical cell system (100, 200, 300) according to claim 1, wherein the transfer arrangement (30, 230, 330) comprises an emission / absorption layer, the emission / absorption layer being arranged to surround the electrochemical cell arrangement (10, 210, 310), and the emission / absorption layer being selectively configured to transfer / receive heat by radiation between the electrochemical cell arrangement (10, 210, 310) and the heating unit (40, 240, 340).

12. The electrochemical cell system (100, 200, 300) according to claim 1, wherein the electrochemical cell arrangement (10, 210, 310) has at least two inlets and two outlets, wherein, When the electrochemical cell arrangement (10, 210) operates as an electrolytic cell, the electrochemical cell arrangement (10, 210) is configured to receive at least electrical energy (EE) at a first inlet and steam (S) at a second inlet as inputs, and supply at least oxygen (O2) at a first outlet and hydrogen (H2) or a suitable syngas containing hydrogen at a second outlet as outputs, and wherein, when the electrochemical cell arrangement (10, 310) operates as a fuel cell, the electrochemical cell arrangement (10, 310) is configured to receive at least oxygen (O2) or air at a first inlet and hydrogen (H2) or a suitable fuel containing hydrogen at a second inlet as inputs, and supply at least electrical energy (EE) at a first outlet and a fluid containing steam (S) at a second outlet as outputs.

13. The electrochemical cell system (300) according to claim 1, wherein the electrochemical cell system further comprises an external energy source (360) thermally coupled to the heating unit (340), in particular a waste heat source and / or a renewable energy source, wherein the external energy source (360) is configured to generate heat, wherein the heating unit (340) is configured to store heat from the external energy source (360).

14. The electrochemical cell system (200) according to claim 1, wherein the electrochemical cell system further comprises a steam generation system (250) thermally coupled to the heating unit (240), wherein the steam generation system (250) is configured to receive water (W) as an input and generate steam (S) as an output, wherein the heating unit (240) is configured to supply heat to the steam generation system (250) to generate steam (S).

15. The electrochemical cell system (200) according to claim 14, wherein the steam (S) generated by the steam generation system (250) is supplied to the electrochemical cell arrangement (210).

16. The electrochemical cell system (300) according to claim 12, wherein the heating unit (340) is thermally coupled to an input of the electrochemical cell arrangement (310), wherein the heating unit (340) is configured to supply heat to the input received by the electrochemical cell arrangement (310) so as to preheat the input.

17. A method for transferring heat between an electrochemical cell arrangement (10) and a heating unit (40), the electrochemical cell arrangement comprising a plurality of cells, the heating unit being external to the cells, the method comprising the following steps: - storing heat from the electrochemical cell arrangement (10) in the heating unit (40) during a charging phase of the heating unit (40), - supplying heat from the heating unit (40) to the electrochemical cell arrangement (10) during a discharging phase of the heating unit (40), - controlling the operation of the electrochemical cell arrangement (10) by a control unit (20), the control unit (20) causing the electrochemical cell arrangement (10) to switch between an operating mode and a non-operating mode, wherein the operating mode of the electrochemical cell arrangement (10) is either only as an electrolytic cell or only as a fuel cell, wherein the charging phase and the discharging phase of the heating unit (40) are performed independently of the operating mode of the electrochemical cell arrangement (10), wherein the step of storing heat and the step of supplying heat are performed by conduction and / or convection and / or radiation.

18. The method according to claim 17, wherein the step of storing heat and the step of supplying heat are performed by a transfer arrangement (30), the transfer arrangement being configured to alternately transfer heat from the electrochemical cell arrangement (10) to the heating unit (40) and from the heating unit (40) to the electrochemical cell arrangement (10).

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