Battery of microtubular solid oxide fuel cells
The perforated plate design in MT-SOFCs addresses thermal stress and oxygen transport issues, enhancing power and safety by improving gas exchange and temperature uniformity, suitable for portable power applications.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- TOPAZ LLC (TOPAZ LLC)
- Filing Date
- 2025-12-26
- Publication Date
- 2026-07-02
AI Technical Summary
Existing microtubular solid oxide fuel cells (MT-SOFCs) face challenges in maintaining optimal operating temperature and oxygen transport efficiency due to thermal stress and stagnant zones, leading to reduced electrical power and safety concerns, especially in compact designs.
Incorporating a perforated plate transversely to the MT-SOFC axis with controlled gaps and a central fuel reformer, enhancing gas exchange and temperature uniformity, while using a housing with spacers to separate anode and cathode regions, ensuring efficient oxidizer flow and heat distribution.
This design increases electrical power, reliability, and safety by maintaining uniform temperature and reducing stagnant zones, while minimizing device size and weight, suitable for portable power sources.
Smart Images
Figure RU2025000435_02072026_PF_FP_ABST
Abstract
Description
[0001] Microtubular solid oxide fuel cell battery.
[0002] The invention relates to energy and can be used in the development of efficient power plants based on high-temperature solid oxide fuel cells (SOFCs). The operating principle of a solid oxide fuel cell is to convert the energy of the chemical reaction between the fuel and oxidizer into electrical energy, without intermediate conversion into thermal and mechanical energy. The operating temperature range of a SOFC is determined by the optimal ionic conductivity temperature of the electrolyte layer and the electrode materials, which is typically 700-1000°C.
[0003] Solid oxide fuel cells (SOFCs) come in a variety of geometric shapes. The most common SOFC geometries are planar and microtubular. A disadvantage of planar geometry is low mechanical resistance to thermal stress due to uneven heating of the fuel cell stack elements. Due to the need to reduce temperature differences in planar SOFC stack elements, the start-up time for such devices can reach 4 hours or more. Tubular SOFCs and stacks eliminate this drawback due to the compensation of thermomechanical loads due to the axial symmetry of the layered structure of such fuel cells. Reducing the diameter of tubular fuel cells to a few millimeters allows for a reach-operating temperature time of 1-3 minutes without cell failure. Tubular SOFCs with a diameter less than 6 mm may be referred to as "microtubular solid oxide fuel cells" (MT-SOFCs).
[0004] Electrically connected MT-SOFCs constitute a fuel cell stack. Most MT-SOFC stack designs have the cathode region on the outside of the fuel cells and rely on the supply of oxidizer to the cathode region of the stack by arranging a flow of atmospheric oxygen. To achieve maximum electrical power from an MT-SOFC stack within the limited dimensions of the stack, it is necessary to arrange the fuel cells as close as possible to one another, thereby increasing the active area of the fuel cells per unit volume. However, reducing the distance between MT-SOFCs negatively impacts oxygen transport to the reaction zone in the cathode region due to the formation of stagnant zones within the cathode volume, reducing the stack's electrical power due to oxygen transport limitations.
[0005] Thus, in order to increase the battery power simultaneously with increasing the packing density of MT-SOFC, it is necessary to ensure acceptable air flow to each MT-SOFC in the battery with a reduction in the volume of stagnant zones inside the cathode region of the battery.
[0006] One of the fuels for generators based on solid fuel oxide fuel cells (SOFCs) is syngas, which can be generated directly in the hot zone of the electrochemical generator. The fuel-air mixture enters a fuel processor—a reformer—located in the central part of the MT-SOFC stack. Through a catalytic partial oxidation reaction, the mixture of the initial organic fuel and air is converted into syngas. The hydrocarbon oxidation reaction generates heat, thereby heating and maintaining the operating temperature of the MT-SOFCs located around the reformer.
[0007] Without the use of additional heat exchangers, the oxidizer flow directed to the cathode region of the stack reduces the temperature of all or individual MT-SOFCs, which negatively impacts the power characteristics of the entire stack. However, maintaining the operating temperature of MT-SOFCs by increasing heat dissipation through increased fuel-air mixture flow rate can lead to an undesirable increase in the temperature gradient within the stack, as well as to some MT-SOFCs exceeding their optimal operating temperature range.
[0008] The use of additional heating equipment (EP 1852930 A1) is also known, which heats the device to speed up the startup process. The heating device is an electric heater. Electric heating is very energy-intensive and disadvantageous in a mobile application due to the limited amount of electrical energy provided by the battery. Furthermore, the use of additional units increases the size of the device itself.
[0009] A device is known from a patent document (DE 102020119019 A1) in which, in order to start a battery, the ignition of a fuel-air mixture is used, in particular, when it reaches the lower end of a microtube using an ignition device.
[0010] The main drawback of this device is its fire hazard. The technical result achieved by the claimed technical solution is to increase the power of the MT-SOFC battery and enhance its reliability and safety while maintaining the overall device size.
[0011] The said technical result is achieved due to the fact that the MT-SOFC stack includes a housing with microtubular solid oxide fuel cells placed therein, distributed throughout the internal volume of the housing and secured by means of at least one spacer (dividing) partition, forming separated cathode and anode spaces within the housing, as well as a central tubular element for supplying fuel gas with a fuel reformer (fuel processor) located therein. The MT-SOFC stack is equipped with at least one perforated plate with openings for the MT-SOFC, located within the housing transversely to the MT-SOFC, wherein the tubes are placed / arranged in the openings of the plate with a gap (with the formation of a gap between the tube and the plasma) of 0.1 - 2 mm. The walls of the housing additionally contain openings for the supply and removal of the oxidizer.
[0012] The proposed invention is illustrated by graphic materials.
[0013] Fig. 1 shows a schematic representation of the MT-SOFC battery without an additional plate.
[0014] Fig. 2 is a schematic representation of an MT-SOFC battery with one additional plate.
[0015] Positions in Fig.1 and Fig.2:
[0016] 1 - battery supporting structure (housing);
[0017] 2 - MT-TOTE;
[0018] 3 - fuel processor (reformer);
[0019] 4 - plate with holes;
[0020] 5 - spacer plate
[0021] 6 - anode region;
[0022] 7 - cathode region
[0023] 8 - distribution zone, in which the fuel gas, coming from the reformer, is distributed and then enters the MT-SOFC;
[0024] black arrows - direction of fuel gas flow;
[0025] white arrows - direction of oxidizer flow.
[0026] Fig. 1 and 2 show a MT-SOFC battery, which includes a battery supporting structure (housing) 1 with microtubular solid oxide fuel cells (MT-SOFC) 2 placed therein. The cells 2 are distributed throughout the internal volume of the housing and are fixed by means of at least one spacer (dividing) partition 5, forming separated anode 6 and cathode 7 spaces within the housing. A central tubular element is formed in the central part of the battery with a fuel reformer 3 (fuel processor) located within it. The central tubular element serves to supply fuel gas.
[0027] To address the problems described in analogs, it is proposed to incorporate at least one metal or ceramic perforated plate in the MT-SOFC battery design, positioned transversely to the MT-SOFC axis. The size of each perforation hole exceeds the outer diameter of the MT-SOFC (to create a gap) or exceeds the size of the zone occupied by a group of several MT-SOFCs, allowing the oxidizer to pass in close proximity to the MT-SOFC. Using at least one such plate directs the oxidizer flow toward the surface of the MT-SOFC cathode layer, thereby reducing the thickness of the near-wall laminar layer of oxidizer flow.
[0028] Plate 4 is in direct contact (rigidly fixed) with the wall of housing 1 or the tubular element housing fuel reformer 3. Using plate 4, which is in thermal contact with fuel reformer 3, increases the electrical power of the entire MT-SOFC stack by increasing the effective gas exchange area of the MT-SOFC and uniformly distributing heat across the stack. Heat transfer (heat output) from the reformer walls increases, thereby further equalizing the temperature fields within the MT-SOFC stack. This also allows for an expanded operating range for the incoming fuel-air mixture flow into the reformer and, correspondingly, the synthesis gas flow leaving it, without the risk of irreversible degradation of the reformer catalyst due to overheating. Using plate 4 also reduces the weight and dimensions of the reformer and increases its service life.
[0029] Furthermore, in addition to increasing the power of the MT-TOTE battery, the use of plates allows for increased reliability and fire and explosion safety of the device while maintaining its dimensions.
[0030] The described technology can be used to create portable (wearable) autonomous power sources of low power and high energy capacity (due to the use of organic fuel) for the wide market of consumer electronics and small robotics.
Claims
Invention formula 1. An MT-SOFC battery comprising a housing with microtubular solid oxide fuel cells placed therein, distributed throughout the internal volume of the housing by means of at least one spacer (dividing) partition with the formation of separated cathode and anode spaces inside the housing, as well as a central tubular element for supplying fuel gas with a fuel reformer (fuel processor) located inside it, wherein the battery is equipped with at least one perforated plate with openings for the MT-SOFC, placed inside the housing transversely to the MT-SOFC, wherein the MT-SOFC are placed / arranged in the openings of the plate with a gap (with the formation of a gap).
2. A battery according to item 1, characterized in that the walls of the housing are provided with openings for the supply and removal of oxidizer.
3. A battery according to claim 1, characterized in that at least one plate has direct thermal contact with the wall of the housing or the tubular element with the fuel reformer located inside it.