Electrochemical cell system with thermal energy storage and related methods

Abstract

1. An electrochemical cell system comprising: an electrochemical cell apparatus; a control unit configured to operate the electrochemical cell apparatus only as an electrolysis cell or only as a fuel cell; a thermal unit external to the electrochemical cell apparatus and thermally coupled to the electrochemical cell apparatus, the thermal unit configured to alternately store heat from the electrochemical cell apparatus to the thermal unit and supply heat from the thermal unit to the electrochemical cell apparatus; and a transfer device configured to alternately transfer heat from the electrochemical cell apparatus to the thermal unit and from the thermal unit to the electrochemical cell apparatus.

Description

[Technical Field]

[0001] The subject matter disclosed herein relates to electrochemical cell systems with thermal energy storage and methods for transferring heat between the electrochemical cell and the thermal energy storage. [Background technology]

[0002] An electrochemical cell is a device that can generate electrical energy from a chemical reaction or use electrical energy to drive a chemical reaction. Typically, 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) comprise at least three main components arranged in a layered structure represented by two electrodes and an electrolyte therebetween.

[0003] Different types of electrochemical cells are currently known and can be classified, for example, by their operating temperature (high-temperature cells, intermediate-temperature cells, and low-temperature cells). For example, solid oxide cells (SOCs) belong to the high-temperature category and typically operate in the temperature range of 500°C to 1000°C, while proton-conducting ceramic cells (PCCs) typically operate in the temperature range of 400°C to 700°C. As already mentioned above, electrochemical cells may operate to generate electrical energy (i.e., as fuel cells) or may use electrical energy to drive chemical reactions (i.e., as electrolyzers). For example, solid oxide electrolyzers use electrical energy to split water (=W) to produce hydrogen (=H) and oxygen (=O), while solid oxide fuel cells use a fuel (typically hydrogen or a fluid containing a high proportion of hydrogen) and an oxidant, typically oxygen, to generate electrical energy (=EE) and steam (and possibly other exhaust streams).

[0004] It should be noted that electrolysis reactions are typically endothermic and therefore require thermal energy, while fuel cells typically operate on exothermic processes, particularly exothermic reactions, thus generating energy. However, high-temperature and intermediate-temperature cells require higher temperatures to operate relative to typical low-temperature cell conditions (e.g., above 500°C). For example, due to its higher operating temperature, a solid oxide electrolyzer can operate in three different electrolysis modes: endothermic, thermoneutral, or exothermic. However, after cell shutdown, the cell temperature will attempt to decrease and may even reach room temperature. Therefore, the transient time of the cell, for example during start-up, can be long, taking several hours to reach operating temperature.

[0005] There are known regenerative solid oxide cells, i.e., cells that can reversibly operate as electrolyzers and fuel cells (see, for example, US Patent Application Publication Nos. 2016 / 0248137 A1, 2013 / 112569 A1, and 2004 / 081859 A1). In particular, regenerative solid oxide cells can store excess heat during exothermic fuel cell mode and release heat during endothermic electrolysis mode to help maintain the cell's reaction zone at operating temperature. From the report "Optimization & Demonstration of a Solid Oxide Regenerative Fuel Cell System" prepared for the US Department of Energy's National Energy Technology Laboratory, it is known to store heat within regenerative solid oxide cells, in particular by using a phase change material (=PCM) integrated into the cell stack to provide heat storage within the regenerative solid oxide cell. From the paper "Improving Hybrid Efficiency and Flexibility by Integrating Thermal Energy Storage into the Fuel Cell System" by Tucker et al., it is known to store heat internally in a solid oxide cell, in particular by using the interconnect material, typically stainless steel, as thermal energy storage. The purpose of the internal heat storage and exchange within the cell is to provide the heat necessary to maintain the reaction zone at operating temperature during electrolysis, and it only operates when the cell is operating (i.e., on), and is therefore highly dependent on the operating state of the cell. Summary of the Invention

[0006] It would be desirable to have an electrochemical cell system having multiple cells optimized to operate solely as electrolyzers or solely as fuel cells, having faster start-up times, and in particular the ability to increase the temperature of the cells prior to subsequent start-up so that the temperature within the cells is substantially at the operating temperature of the cells at start-up, thereby improving cell performance. It would also be desirable to have an electrochemical cell system that includes a thermal unit that can operate independently of system operation, i.e., that can exchange heat with the cells both when the cells are operating (i.e., on) and when the cells are not operating (i.e., off).

[0007] According to one aspect, the subject matter disclosed herein relates to a system of electrochemical cells comprising an electrochemical cell apparatus, a control unit configured to operate the electrochemical cell apparatus only as an electrolysis cell or only as a fuel cell, a thermal unit external to the electrochemical cell apparatus and thermally coupled to the electrochemical cell apparatus and configured to alternately store heat from the electrochemical cell apparatus to the thermal unit and supply heat from the thermal unit to the electrochemical cell apparatus, and a transfer device configured to alternately transfer heat from the electrochemical cell apparatus to the thermal unit and from the thermal unit to the electrochemical cell apparatus. [Brief explanation of the drawings]

[0008] A more complete understanding of the disclosed embodiments of this invention and many of the attendant advantages thereof will be readily obtained as the same become better understood by reference to the following detailed description when considered in connection with the accompanying drawings. [Figure 1] 1 shows a simplified diagram of a first general embodiment of an innovative electrochemical cell system. [Figure 2] 2 shows a simplified diagram of the embodiment of FIG. 1 when operating as an electrolytic cell during the charging phase of the thermal unit. [Figure 3] 2 shows a simplified diagram of the embodiment of FIG. 1 when operating as a fuel cell during the charging phase of the thermal unit. [Figure 4]1 shows a simplified diagram of a second embodiment of an innovative electrochemical cell system with a vapor generation system during the discharge phase of a thermal unit. [Figure 5] 1 shows a simplified diagram of a third embodiment of an innovative electrochemical cell system with an external energy source during the discharge phase of the thermal unit. DETAILED DESCRIPTION OF THE INVENTION

[0009] According to one aspect, the subject matter disclosed herein relates to an electrochemical cell system that consumes at least electrical energy and water to produce at least hydrogen (=H2) or consumes a fuel containing at least hydrogen (=H2) and an oxidant to produce at least electrical energy when the electrochemical cell is operating, and is provided with a thermal storage unit (external to the electrochemical cell) adapted to transfer heat to and from the electrochemical cell to reduce the start-up time of the cell and thus comply with a variable load, such as a renewable energy system. The thermal storage unit may be charged when the electrochemical cell is operating (i.e., the thermal storage unit receives and stores heat) and may be discharged when the electrochemical cell is not operating (i.e., the thermal storage unit provides heat to the electrochemical cell). Advantageously, the innovative electrochemical cell system can use the thermal storage unit to keep the electrochemical cell at an elevated temperature, preferably at an operating temperature, or to increase the cell temperature before operation of the cell to reduce the start-up time of the cell. Heat transfer between the electrochemical cell and the thermal storage unit can be achieved by conduction and / or convection and / or irradiation by suitable means.

[0010] In accordance with another aspect, the subject matter disclosed herein relates to a method for transferring heat between an electrochemical cell and a thermal reservoir that is external to the electrochemical cell and that can be charged and discharged independently of the operating mode of the electrochemical cell.

[0011] It should be noted that for the purposes of this disclosure, an "electrochemical cell system" is a system comprising electrochemical cells that can process chemicals or fuels for energy purposes (i.e., a fuel cell) or that can use energy for water splitting purposes (i.e., an electrolyzer). In particular, as better explained below, when the electrochemical cell system is configured to operate as an electrolyzer, the electrochemical cell system can perform electrolysis of water, particularly steam, to produce at least hydrogen, or the electrochemical cell system can perform co-electrolysis of CO and water, particularly steam, to produce a synthesis gas that includes at least hydrogen. For example, the electrochemical cell system may include a solid oxide cell (=SOC) or a proton-conducting ceramic cell (=PCC). However, other types of cells may also be used, particularly high-temperature or medium-temperature cells, e.g., cells having an operating temperature greater than 100°C, preferably greater than 200°C.

[0012] Next, embodiments of the present disclosure will be described in detail, examples of which are illustrated in the drawings. The examples and drawings are provided as an explanation of the present disclosure and should not be construed as limiting the present disclosure. Indeed, 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 spirit of the present disclosure. In the following description, like reference numerals are used in the illustrative drawings of the embodiments to indicate elements that perform the same or similar functions. Moreover, for clarity of illustration, some reference numerals may not be repeated in all figures.

[0013] Figure 1 shows a simplified diagram of a first embodiment of an innovative electrochemical cell system 100, hereinafter referred to as "electrochemical cell system 100" or simply "system 100." Figures 2 and 3 show a first embodiment of the innovative electrochemical cell system 100 operating as an electrolysis cell during the charging phase of the thermal unit and a first embodiment of the innovative electrochemical cell system 100 operating as a fuel cell during the charging phase of the thermal unit, respectively. Second and third embodiments of innovative electrochemical cell systems 200 and 300 are described below with reference to Figures 4 and 5.

[0014] 1, system 100 includes an electrochemical cell apparatus 10 including a plurality of electrochemical cells, typically in the form of a stack 11, all of which are electrically coupled to one another. 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 is contemplated. Advantageously, electrochemical cell apparatus 10 includes intermediate-temperature or high-temperature cells, and possibly electrochemical cell apparatus 20 includes a plurality of solid oxide cells (=SOC).

[0015] Advantageously, each cell of the electrochemical cell arrangement comprises 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 may be or comprise an n-type or p-type semiconductor layer.

[0016] Advantageously, the cells of the electrochemical cell device are in a solid state at least at room temperature, especially when solid oxide cells (=SoC) or proton conducting ceramic cells (=PCC) are used, the cells of the electrochemical cell device are in a solid state both at room temperature and at the operating temperature.

[0017] Advantageously, the electrolyte of the electrochemical cell device is permeable to ions at least at the operating temperature. For example, if a solid oxide cell (=SOC) is used, the electrolyte is permeable to ions O - On the other hand, if a proton conducting ceramic cell (=PCC) is used, the electrolyte is permeable to ions H + However, as mentioned above, other types of cells may also be used, in particular medium-temperature or high-temperature cells.

[0018] It should be noted that the electrochemical cell system can operate in two different modes: as an electrolysis cell or as a fuel cell. In other words, the electrochemical cell device is not configured to switch between an operating mode as an electrolysis cell and an operating mode as a fuel cell, but rather is configured to switch only between an operating mode (in which the electrochemical cell operates as an electrolysis cell or a fuel cell) and a non-operating mode (in which the electrochemical cell does not operate). When the electrochemical cell system operates in the electrolysis cell mode, the system consumes at least electrical energy and steam to produce at least hydrogen, while when operating in the fuel cell mode, the system consumes at least hydrogen (or any suitable fuel containing hydrogen, e.g., methane) and an oxidant, e.g., air, to produce at least electrical energy.

[0019] The system 100 further includes a control unit 20 configured to operate the electrochemical cell apparatus 10 solely as an electrolysis cell or solely as a fuel cell. By way of non-limiting example, the control unit 10 may be a computer, programmable controller, microprocessor, or similar device. As better described below, the control unit 20 may be programmed to operate the electrochemical cell apparatus 10 according to, for example, a predetermined time schedule and / or a predetermined operating mode. As better described below, the control unit 20 may be configured to operate and possibly control other elements of the system 100.

[0020] According to one embodiment, particularly when the electrochemical cell apparatus 10 operates as an electrolysis cell (see, e.g., FIG. 2), the electrochemical cell apparatus 10 is configured to receive at least electrical energy (EE) from an external energy source, advantageously a renewable energy source, such as a solar or wind power plant. Considering that renewable electricity generation from renewable energy sources is generally variable and / or intermittent, e.g., may depend on the amount of sunlight at a given location and time, or wind speed, air density, and turbine characteristics (among other factors), the electrochemical cell apparatus 10 may be configured to operate intermittently.

[0021] According to another embodiment, particularly when the electrochemical cell apparatus 10 operates as a fuel cell (see, for example, FIG. 3), the electrochemical cell apparatus 10 may be configured to generate electrical energy (=EE) starting from at least hydrogen or a suitable fuel containing hydrogen, such as methane. Given that electrical energy demand is generally not constant over time (i.e., is intermittent and / or has a variable load profile), the electrochemical cell apparatus 10 may also be configured to operate intermittently.

[0022] Advantageously, the control unit 20 may be programmed to control the electrochemical cell apparatus 10 according to a predetermined strategy. For example, if the electrochemical cell apparatus 10 receives electrical energy from a solar power plant, the control unit 20 may control the operation of the electrochemical cell apparatus based on the times when the sun rises and sets. According to one example, the electrochemical cell apparatus 10 may be turned on at 8:00 and turned off at 18:00. However, since electrochemical cells typically have high operating temperatures, e.g., higher than 500°C, the electrochemical cell apparatus 10 takes time to reach its operating temperature after being switched on (the so-called "start-up time"), thus reducing the performance of the system.

[0023] The system 100 further comprises a thermal unit 40 external to the electrochemical cell apparatus 10, the thermal unit 40 being thermally coupled to the electrochemical cell apparatus 10 and configured to alternately store heat from the electrochemical cell apparatus 10 to the thermal unit 40 and supply heat from the thermal unit 40 to the electrochemical cell apparatus 10. By way of non-limiting example, the thermal unit 40 may be a thermal storage tank using a heat storage medium (e.g., molten salt, phase change material, metal mixture, etc.) or a similar device for storing thermal energy. In particular, as better explained below, the thermal unit 40 may store heat from the electrochemical cell apparatus 10, and possibly from an external energy source (e.g., see external energy source 360 ​​in FIG. 5 ), (charging phase), and supply heat to the electrochemical cell apparatus 10 (discharging phase) independently of the operating mode of the electrochemical cell apparatus 10. In particular, the thermal unit 40 can store heat and provide heat both when the electrochemical cell device 10 is operating (i.e., on) and when the electrochemical cell device 10 is not operating (i.e., off), and / or the thermal unit 40 can store heat and provide heat both when the electrochemical cell device 10 is operating as an electrolysis cell and when the electrochemical cell device 10 is operating as a fuel cell.

[0024] According to one possibility, the thermal unit 40 can store heat when the electrochemical cell apparatus 10 is operating, for example, between 8:00 and 18:00, referring to the previous example but not limited thereto, particularly during the entire operating time or during one or more time intervals during the operating time. According to one possibility, the thermal unit 40 can supply heat to the electrochemical cell apparatus 10 when the electrochemical cell apparatus 10 is not operating, for example, between 18:00 and 8:00, referring to the previous example but not limited thereto. Advantageously, the thermal unit 40 is configured to supply heat to the electrochemical cell apparatus 10 just before turning on the electrochemical cell apparatus 10, for example, between 6:00 and 8:00, or generally at a suitable time interval, to heat the electrochemical cell apparatus 10 to reach the operating temperature of the electrochemical cell at the time of turning on the electrochemical cell apparatus 10.

[0025] Advantageously, the control unit 20 is further configured to control the operation of the thermal unit 40. In particular, the control unit 20 may be configured to control the amount of heat stored in the thermal unit 40, for example the charge / discharge state of the thermal unit 40. Advantageously, the thermal unit 40 is arranged around the electrochemical cell apparatus 10. More advantageously, the electrochemical cell system further comprises an insulating enclosure arranged around the thermal unit 40.

[0026] The electrochemical cell system 100 further comprises a transfer device 30 configured to transfer heat alternately from the electrochemical cell device 10 to the thermal unit 40 and from the thermal unit 40 to the electrochemical cell device 10. As will be better explained below, the transfer device 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 device 30 to alternately turn it on and off. In particular, when the transfer device 30 is turned on, heat transfer between the thermal unit 40 and the electrochemical cell device 30 is possible; in other words, when the transfer device 30 is turned on, the thermal unit 40 can store energy from the electrochemical cell device 30 or supply energy to the electrochemical cell device 30.

[0027] To transfer heat by conduction, the transfer device 30 advantageously comprises solid-state devices mechanically coupled to the electrochemical cell apparatus 10 and the thermal unit 40 and configured to transfer heat by conduction between the electrochemical cell apparatus 10 and the thermal unit 40. Possibly, the electrochemical apparatus may be in the form of one or more rods or plates, and advantageously, the solid-state devices are a plurality of rods or plates. When the charge / discharge phase of the thermal unit 40 is required, the solid-state devices may be in contact with the electrochemical cell apparatus 10, in particular, located between each electrochemical cell, to transfer heat between the thermal unit 40 and the electrochemical cell apparatus 10. Alternatively, when heat exchange between the thermal unit 40 and the electrochemical cell apparatus 10 is not required, the solid-state devices are spaced apart in such a way as to avoid contact with the electrochemical cell apparatus 10 and avoid heat exchange. Advantageously, the control unit 20 can adjust the position of the solid-state devices. More advantageously, the position of each rod or plate can be adjusted independently to allow for finer adjustment of the amount of heat transferred between the thermal unit 40 and the electrochemical cell apparatus 10.

[0028] To transfer heat by convection, the transfer device 30 advantageously comprises a fluid circuit configured to circulate a fluid between the electrochemical cell arrangement 10 and the thermal unit 40 and to transfer heat by convection between the electrochemical cell arrangement 10 and the thermal unit 40. Possibly, 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 further comprises a mechanically operated machine (e.g., a fan or a pump) and possibly also a control valve to regulate the amount of fluid circulating in the fluid circuit.

[0029] In order to transfer heat by irradiation, the transfer device 30 advantageously comprises an emitting / absorbing layer arranged around the electrochemical cell device 10 and configured to selectively transfer heat by radiation (which can be emitted or absorbed) between the electrochemical cell device 10 and the thermal unit 40. It should be noted that the emitting / absorbing layer can receive heat from the electrochemical cell device 10 to the thermal unit 40 (i.e., operate as an emitting layer during the charging phase of the thermal unit 40) and can supply heat from the thermal storage unit 40 to the electrochemical cell device 10 (i.e., operate as an absorbing layer during the discharging phase of the thermal unit 40). Possibly, the transfer device 30 further comprises an insulating layer (or a reflective layer) to adjust the amount of heat transferred between the thermal unit 40 and the electrochemical cell device 10. Advantageously, the control unit 20 can adjust the position of the insulating layer when it is located wholly or partially between the thermal unit 40 and the electrochemical cell device 10 so that heat exchange between them is completely or partially stopped.

[0030] As previously mentioned, the electrochemical cell apparatus 10 can operate as either an electrolysis cell or a fuel cell. FIG. 2 illustrates the electrochemical cell system 100 when operating as an electrolysis cell, particularly during the charging phase of the thermal unit 40. The electrochemical cell apparatus 10 has at least two inlets and two outlets. Specifically, the electrochemical cell apparatus 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 apparatus 10 is configured to provide 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 of the figures, the electrochemical cell apparatus 10 is further configured to receive carbon dioxide CO2 as input at a third inlet and provide a hydrogen-containing synthesis gas as output at a second outlet. It should be noted that other flue gases may be produced by the electrochemical cell apparatus 10, depending, for example, on the purity of the inlet stream.

[0031] FIG. 3 illustrates the electrochemical cell system 100 when operating as a fuel cell, particularly during the charging phase of the thermal unit 40. The electrochemical cell device 10 has at least two inlets and two outlets. Specifically, the electrochemical cell device 10 is configured to receive as inputs at least oxygen O or air, particularly ambient air, at a first inlet and hydrogen H or a suitable fuel containing hydrogen at a second inlet. It should be noted that the hydrogen H provided at the second inlet may be pure hydrogen (or substantially pure, e.g., having a purity of 95% or greater) or may be mixed with other substances, particularly carbon (e.g., provided in the form of a hydrocarbon fuel, e.g., methane). The electrochemical cell device 10 is configured to provide as outputs at least electrical energy EE at a first outlet and steam S at a second outlet. It should be noted that other flue gases may be produced by the electrochemical cell device 10, depending, for example, on the purity of the hydrogen and / or the oxidant (oxygen or air) used.

[0032] A second embodiment of an electrochemical cell system 200 is described below with reference to Figure 4. It should be noted that elements 210, 211, 220, 230, and 240 in Figure 4 may be identical to or similar to elements 10 (electrochemical cell apparatus), 11 (electrochemical cell stack), 20 (control unit), 30 (transmitter), and 40 (thermal unit), respectively, in Figure 1, and may perform the same or similar functions. It should also be noted that the electrochemical cell system 200 in Figure 4 is shown operating as an electrolytic cell, particularly during the discharge phase of thermal unit 240, as will become apparent below.

[0033] 4, the electrochemical cell system 100 may further include a steam generation system 250 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 thermal unit 240 such that the thermal unit 240 can provide heat to the steam generation system 250 to generate the steam S.

[0034] 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 amount of heat transferred from the thermal unit 240 to the steam generation system 250, e.g., to control the amount of steam S generated by the steam generation system 250.

[0035] A third embodiment of an electrochemical cell system 300 is described below with reference to Figure 5. It should be noted that elements 310, 311, 320, 330, and 340 in Figure 5 may be the same as or similar to elements 10 (electrochemical cell apparatus), 11 (electrochemical cell stack), 20 (control unit), 30 (transmitter), and 40 (thermal unit), respectively, in Figure 1, and may perform the same or similar functions. It should also be noted that electrochemical cell system 300 in Figure 5 is shown operating as a fuel cell, particularly during the discharge phase of thermal unit 340, as will become apparent below.

[0036] Referring non-limitingly to FIG. 5 , the electrochemical cell apparatus 310 is configured to receive preheated inputs, particularly fuel and oxidant (e.g., hydrogen and oxygen) at temperatures significantly higher than ambient temperature. Possibly, the steam S generated by the electrochemical cell apparatus 310 as output is still at a high temperature, and its heat can be utilized to preheat the input of the electrochemical cell apparatus 310. In particular, the flow of steam S can provide heat to the fuel and oxidant used as inputs to the electrochemical cell apparatus 310; for example, the electrochemical cell system 300 can include a dedicated heat exchanger 355 in which heat is exchanged between the steam S and the inputs, particularly hydrogen H (or a suitable fuel containing hydrogen) and oxygen O. Note that the heat exchanger 355 can be external to the electrochemical cell apparatus 310 or integrated with the electrochemical cell apparatus 310. Note also that the steam S at the outlet of the heat exchanger 355 can be lower-temperature steam S or a mixture of steam S and water W or liquid water W.

[0037] Alternatively or additionally, the thermal unit 340 may further provide heat to preheat the inputs received by the electrochemical cell apparatus 310. In particular, the thermal unit 340 may be thermally coupled to the fuel and oxidant used as inputs to the electrochemical cell apparatus 310; for example, the thermal unit may supply heat to a dedicated heat exchanger 355 where the heat exchange occurs.

[0038] 5, the electrochemical cell arrangement 310 further comprises an external energy source 360, in particular a waste heat source and / or a renewable energy source, thermally coupled to the thermal unit 340. Advantageously, the external energy source 360 ​​is configured to generate heat, in particular to provide heat to the thermal unit 340. Advantageously, the thermal unit 340 is configured to store heat received from the external energy source.

[0039] According to another aspect, the subject matter disclosed herein relates to a method for transferring heat between an electrochemical cell apparatus 10 comprising a plurality of electrochemical cells and a thermal unit 40 external to the electrochemical cells, the method comprising: - storing heat from the electrochemical cell arrangement 10 in the thermal unit 40 during the charging phase of the thermal unit 40; - supplying heat from the thermal unit 40 to the electrochemical cell arrangement 10 during the discharge phase of the thermal unit 40; - controlling the operation of the electrochemical cell apparatus 10 through the control unit 20, where the control unit 20 switches the electrochemical cell apparatus 10 between an operating mode and a non-operating mode.

[0040] It should be noted that the operating mode of the electrochemical cell device 10 is only as an electrolysis cell or only as a fuel cell; in other words, the electrochemical cell device 10 is not configured to switch between an operating mode as an electrolysis cell and an operating mode as a fuel cell, but is configured to switch only between an operating mode (where the electrochemical cell operates as an electrolysis cell or a fuel cell) and a non-operating mode (where the electrochemical cell is not operating).

[0041] It should also be noted that the charging and discharging phases of the thermal unit 40 occur independently of the operating mode of the electrochemical cell apparatus 10. In particular, the thermal unit 40 can be charged and discharged both when the electrochemical cell apparatus 10 is operating as an electrolysis cell and when the electrochemical cell is operating as a fuel cell, and / or when the electrochemical cell apparatus 10 is operating and when the electrochemical cell apparatus 10 is not operating.

[0042] It is also noted that the steps of storing and supplying heat are performed by conduction and / or convection and / or radiation. Advantageously, the steps of storing and supplying heat are performed via a transfer device 30 configured to alternately transfer heat (by conduction and / or convection and / or radiation) from the electrochemical cell apparatus 10 to the thermal unit 40 and from the thermal unit 40 to the electrochemical cell apparatus 10. It is noted that the thermal unit 40 can further store heat from an external heat source, for example a waste heat source or a renewable energy source.

Claims

1. An electrochemical cell system (100, 200, 300) comprising: an electrochemical cell device (10, 210, 310) comprising a plurality of cells; a control unit (20, 220, 320) configured to operate said electrochemical cell device (10, 210, 310) only as an electrolysis cell or only as a fuel cell; a thermal unit (40) thermally coupled to the electrochemical cell device (10, 210, 310), configured to alternately store heat from the electrochemical cell device (10, 210, 310) to the thermal unit (40, 240, 340) and supply heat from the thermal unit (40, 240, 340) to the electrochemical cell device (10, 210, 310); a transfer device (30, 230, 330) configured to transfer heat alternately from the electrochemical cell device (10, 210, 310) to the thermal unit (40, 240, 340) and from the thermal unit (40, 240, 340) to the electrochemical cell device (10, 210, 310), the thermal unit (40, 240, 340) is external to the electrochemical cell device (10, 210, 310); The electrochemical cell system (100, 200, 300), wherein the transfer device (30, 230, 330) is configured to transfer heat by conduction and / or convection and / or radiation.

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

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

4. 3. The electrochemical cell system (100, 200, 300) of claim 2, wherein the electrolyte of the electrochemical cell device (10, 210, 310) is permeable to ions at least at cell operating temperatures.

5. 2. The electrochemical cell system of claim 1, wherein the control unit is further configured to operate the transmission device to alternately turn the transmission device on and off.

6. 2. The electrochemical cell system (100, 200, 300) of claim 1, wherein the thermal unit (40, 240, 340) is disposed around the electrochemical cell device (10, 210, 310).

7. The electrochemical cell system (100, 200, 300) of claim 1, further comprising an insulating enclosure disposed around the thermal unit (40, 240, 340).

8. 2. The electrochemical cell system of claim 1, wherein the transfer device comprises a solid-state device mechanically coupled to the electrochemical cell apparatus and the thermal unit, the solid-state device configured to transfer heat by conduction between the electrochemical cell apparatus and the thermal unit.

9. 2. The electrochemical cell system of claim 1, wherein the transfer device comprises a fluid circuit configured to circulate a fluid between the electrochemical cell device and the thermal unit, the fluid circuit configured to transfer heat by convection between the electrochemical cell device and the thermal unit.

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

11. 2. The electrochemical cell system of claim 1, wherein the transfer device comprises an emitting / absorbing layer disposed around the electrochemical cell device, the emitting / absorbing layer being selectively configured to transfer / receive heat by radiation between the electrochemical cell device and the thermal unit.

12. the electrochemical cell device (10, 210, 310) has at least two inlets and two outlets; When the electrochemical cell apparatus (10, 210) operates as an electrolysis cell, the electrochemical cell apparatus (10, 210) is configured to receive as inputs at least electrical energy (EE) at a first inlet and steam (S) at a second inlet, and to provide as outputs at least oxygen (O2) at a first outlet and hydrogen (H2) or a suitable synthesis gas comprising hydrogen at a second outlet; 10. The electrochemical cell system of claim 1, wherein when the electrochemical cell device operates as a fuel cell, the electrochemical cell device is configured to receive as inputs at least oxygen (O2) or air at a first inlet and hydrogen (H2) or a suitable fuel comprising hydrogen at a second inlet, and to provide as outputs at least electrical energy (EE) at a first outlet and a fluid comprising steam (S) at a second outlet.

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

14. a steam generating system (250) thermally coupled to the thermal unit (240); the steam generation system (250) is configured to receive water (W) as an input and to generate steam (S) as an output; The electrochemical cell system (200) of claim 1, wherein the thermal unit (240) is configured to provide heat to the steam generation system (250) to generate steam (S).

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

16. the thermal unit (340) is thermally coupled to the input of the electrochemical cell device (310); 13. The electrochemical cell system (300) of claim 12, wherein the thermal unit (340) is configured to provide heat to an input received by the electrochemical cell device (310) to preheat the input.

17. A method for transferring heat between an electrochemical cell device (10) including a plurality of cells and a thermal unit (40) external to the cells, comprising: - storing heat from the electrochemical cell device (10) in the thermal unit (40) during the charging phase of the thermal unit (40); - supplying heat from said thermal unit (40) to said electrochemical cell device (10) during the discharge phase of said thermal unit (40); - controlling the operation of the electrochemical cell device (10) by a control unit (20), the control unit (20) switching the electrochemical cell device (10) between an operating mode and a non-operating mode, the electrochemical cell device (10) operates only as an electrolysis cell or only as a fuel cell; the charging and discharging phases of the thermal unit (40) are performed independently of the operating mode of the electrochemical cell device (10); A method wherein the steps of storing heat and providing heat are performed by conduction and / or convection and / or radiation.

18. 20. The method of claim 17, wherein the steps of storing heat and supplying heat are performed through a transfer device (30) configured to transfer heat alternately from the electrochemical cell device (10) to the thermal unit (40) and from the thermal unit (40) to the electrochemical cell device (10).

Images