Stack Rack System

Abstract

The present invention relates to a cell stack unit (20) for a redox flow battery, which comprises a plurality of battery core stacks (12), each of which similarly comprises a plurality of battery cells, stacked along a stacking direction (S) to form at least one battery column (10), connected within the at least one battery column (10) by connection elements (14), the connection elements being provided between pairs of core stacks (12), and the battery cells adapted to generate electricity through a redox reaction of two types of energy storage electrolyte solutions; and a rack (22) extending on both sides of the at least one battery column (10) in the stacking direction (S), the rack (22) having at least one first end plate (14). The present invention also relates to a redox flow battery comprising a battery stack unit (20) including a rack (22) having a first end plate (16a) arranged to support at least one battery column (10) at a first end in a stacking direction (S), a tensioning system (30) provided on the rack (22) and adapted to tension the at least one battery column (10) by at least one second end plate (16b) toward the first end plate (16a) at a second end of the battery column in the stacking direction (S), a fluid system adapted to supply two types of energy storage electrolyte solutions from respective reservoir containers to the battery cells, and an electrical system (36) adapted to output power generated in the battery cells.

Description

[Technical Field]

[0001] The present invention relates to a cell stack unit for a redox flow battery and a redox flow battery including such a cell stack unit. [Background technology]

[0002] A redox flow battery is a well-known type of electrochemical cell in which two energy-storing electrolyte solutions are pumped along separate sides of a membrane in each flow chamber, resulting in ions being transported through the membrane separating the two solutions into the interior of the battery, and a voltage being applied between the positive and negative current collectors assigned to each of the two solution flow chambers.

[0003] Redox flow batteries may therefore be used in similar scenarios to fuel cells or rechargeable batteries, with the advantage that the corresponding electrolyte solutions can be easily stored in tanks of any size, so that there are no fundamental technical limits to the achievable capacity, especially if replaceable and refillable tanks are used.

[0004] Examples of redox flow batteries and related techniques and methods are known, for example, from the prior art documents US Pat. No. 5,629,299, ... and US Pat. No. 5,629,299.

[0005] Here, Patent Document 1 describes a flow battery unit and an energy storage system in which the necessary components are assembled monolithically without requiring high modularity. In particular, the piping for supplying the electrolyte solution is fixedly arranged around the cell stack unit, making it difficult to easily replace or access individual battery cells. Similarly, Patent Document 2 discloses a cell frame for a redox flow battery and a redox flow battery in which four core stacks are mounted between a pair of end plates. The corresponding frame is very bulky since it includes the fluid delivery system for the cell stack, which reduces the flexibility of the entire system.

[0006] Furthermore, Patent Document 3 discloses a double-stack redox flow battery in which a battery stack consisting of two core stacks is arranged between a pair of end plates. Again, the rack of the system is very large and complex to manufacture. Patent Document 4 relates to a system and method for a redox flow battery in which the battery stacks are individually connected to a fluid supply system. Here, the rack merely serves to hold the battery stack in place, but does not contribute to compressing the individual batteries, which must be addressed by additional means.

[0007] Therefore, all redox flow batteries and cell stack units known from the prior art are disadvantageous with respect to their flexibility, modularity and integration, and there is a need for an improved redox flow battery and cell stack unit for that purpose that is suitable for outputting large power while at the same time maintaining a largely modular and economical design. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Chinese Utility Model No. 210723236 [Patent Document 2] US Patent Application Publication No. 2008 / 081247 [Patent Document 3] U.S. Patent Application Publication No. 2021 / 359331 [Patent Document 4] International Publication No. 2016 / 007555 Summary of the Invention

[0009] For this purpose, the battery stack unit for the redox flow battery according to the present invention comprises a plurality of battery core stacks, each of which similarly comprises a plurality of battery cells, the plurality of battery cells being stacked along a stacking direction to form at least one battery column, and being connected within the at least one battery column by connection elements, the connection elements being provided between pairs of the battery core stacks, and the battery cells being adapted to generate power through a redox reaction of two kinds of energy storage electrolyte solutions. The battery stack further includes a rack extending on both sides of at least one battery column in a stacking direction, the rack having at least one first end plate disposed thereon and arranged to support the at least one battery column at a first end in the stacking direction; a tensioning system disposed on the rack (22), the tensioning system adapted to pull the at least one battery column by the at least one second end plate toward the first end plate at a second end of the battery column in the stacking direction; a fluid system adapted to supply two types of energy storage electrolyte solutions to the battery cells from respective reservoir containers; and an electrical system adapted to output power generated in the battery cells.

[0010] By adopting such a design for a cell stack unit for a redox flow battery, theoretical power output values ​​of 50 or even 100 kW or more can be realized due to the modularization of battery cells into battery core stacks and battery columns. Furthermore, by integrating multiple battery cells into interchangeable battery core stacks, a high degree of standardization and modularization can be achieved, and prefabricated and tested components and modules can be employed to reduce installation and mounting efforts. Furthermore, structural materials and peripheral components can also be reduced due to the modular and highly efficient design of the cell stack unit of the present invention.

[0011] Furthermore, in the event of a malfunction of a battery core stack, the battery core stack can be easily serviced in the cell stack unit of the present invention. The battery core stack can be quickly and efficiently replaced with a corresponding replacement unit, even if it is already installed. The corresponding replacement unit can be tested for proper operation before replacement. In summary, the modular design of the cell stack unit of the present invention allows for economical integration of modular battery core stacks that are easy and inexpensive to manufacture into cell stack units with high potential power output, reducing the required piping and electrical wiring effort.

[0012] In a specific embodiment of the battery stack unit according to the present invention, the stacking direction of at least one battery column can correspond to a substantially horizontal or vertical direction, which allows easy access to the individual battery core stacks from the side of the battery stack unit, thus improving the maintainability of the battery stack unit and facilitating the installation of the corresponding redox flow battery.

[0013] In particular, the battery core stacks of the cell stack unit according to the present invention can be configured as self-contained modules that can be individually inserted into a rack. To this end, each core stack can be equipped with all necessary interface components, in particular for the supply of electrolyte solution, electrical wiring, and possibly a cooling assembly for cooling the battery core stack during its operation. These interface components can, if necessary, also include a tensioning system that exerts attachment forces, particularly directed in the stacking direction, pressure forces from electrode felts or gaskets, etc., to ensure the structural integrity of each core stack with its cells. To provide an inexpensive solution, the tensioning system does not necessarily have to exert pressure-induced forces during leak tests or normal operation.

[0014] To further enhance the modularity and maintainability of the battery stack unit of the present invention, one first and / or second end plate may be provided for each battery column. In such an embodiment, each battery column would be individually compressed and removed if one of its battery core stacks needed to be replaced. However, alternative embodiments are contemplated in which one first and / or second end plate is provided for each of a plurality of battery columns.

[0015] In a specific embodiment of the present invention, the fluid system may include a pair of manifold lines for each of the two electrolyte solutions, each pair including a feed line and a return line, and a pair of branch lines for each of the two electrolyte solutions and each battery column. By adopting this type of fluid system, the piping effort required to supply the electrolyte solution to all the battery cells of the cell stack unit is minimized, and the modularization of the battery core stack is also considered.

[0016] In particular, each pair of branch lines of a battery column may penetrate at least one first end plate of the corresponding at least one battery column to further reduce the installation effort. Alternatively, the pair of branch lines may be guided outside the at least one battery column, and preferably each core stack is individually connected to a respective branch line. In such an embodiment, the branch lines may be located outside the battery column, which, on the one hand, increases the required installation space and may hinder access to the battery core stacks from each side, but, on the other hand, may facilitate the installation and surface connection of the individual battery core stacks in each battery column due to their easier connection to the fluid system.

[0017] Furthermore, the fluid system may also include a separate pump for each of the electrolyte solutions. By allocating the two pumps to a cell stack unit, the resulting redox flow battery requires fewer external components for operation, making it more flexible and independent.

[0018] Furthermore, in the battery stack unit according to the present invention, the fluid system may further include a collecting basin for leaked electrolyte solution, and preferably a leak sensor is provided in the collecting basin, which can prevent the electrolyte solution from leaking out of the battery stack unit. In order to prevent further damage to the system and ensure the proper operation of the battery stack unit, a corresponding leak sensor can be further provided at an appropriate position, allowing early detection and recovery of possible malfunctions in the fluid system.

[0019] Furthermore, the fluid system may also include at least one sensor unit, such as a pressure sensor and / or a temperature sensor, preferably provided in one of the manifold lines; the fluid system may also include a heat exchanger; at least one current and / or voltage sensor may be provided in at least one of the core stacks; and / or the battery stack unit may also include at least one structure-borne sound sensor. All of the above sensor types may further serve to ensure proper operation of the battery stack unit by detecting any malfunctions or undesirable operating conditions of the battery stack unit and in particular its fluid system. The data collected by the individual sensor units may be transferred to a corresponding control unit adapted for further processing of the data, such as the control unit of a corresponding redox flow battery described below.

[0020] To further facilitate electrical wiring of the individual battery core stacks within at least one cell column, they may be alternately oriented with opposite polarities, such that each pair of positive and negative terminals of adjacent battery core stacks are positioned adjacent to one another and can be contacted, for example, by a single current collector element, thereby further reducing the number of components in the electrical system and facilitating its installation.

[0021] In particular, the electrical system may include at least one pair of bus bars extending along the stacking direction to which each core stack or a group of series-connected core stacks can be connected, preferably from below, via the current collectors. This feature also enhances the modularity and maintainability of the battery stack unit according to the present invention, thereby contributing to the optimization of the electrical system.

[0022] To enable connection of the battery stack to a higher voltage grid or DC bus, the battery stack unit according to the present invention may further comprise a power conversion system. It may be particularly beneficial if the power conversion system is located near the battery stack itself to reduce wiring length. This may be achieved by positioning one or more corresponding electrical cabinets directly beside or above the battery stack, in particular mounted on the same rack or skid. Thus, cable length and associated electrical losses can be reduced. The same applies to electrical fuses and switches.

[0023] In a specific embodiment of the battery stack unit of the present invention, the rack may be configured as a frame extending around at least one battery column, with two longitudinal sides extending along the stacking direction and two transverse sides extending perpendicular thereto. One of the two transverse sides may be provided with at least one first end plate, the other of the two transverse sides may be provided with a tensioning system, and / or the rack may be provided with attachment points for moving the battery stack unit, for example, by an external crane. Such a rack design may ensure sufficient mechanical stability and rigidity of the battery stack unit while allowing access to the individual battery core stacks from at least one side, thereby reducing the overall weight and material required to assemble the battery stack unit of the present invention.

[0024] Although various types of battery cells can in principle be employed in the cell stack unit according to the invention, in particular, in a particularly efficient embodiment, all of the battery cells may be formed substantially identically and / or the effective area of ​​at least one of the battery cells in a cross section relative to the stacking direction may be less than 2500 cm 2 Below, especially 1000cm 2 It can be the following:

[0025] According to a second aspect, the present invention relates to a redox flow battery, comprising a cell stack unit according to the present invention as described above, at least two reservoir containers for an electrolyte solution for energy storage coupled to a fluid system of the cell stack unit, and a control unit adapted to control and / or monitor the operation of the redox flow battery. The control unit may, for example, receive sensor data from the sensor unit and may control the power output and the electrolyte supply to the individual battery cells during operation of the battery. Furthermore, the at least two reservoir containers may be replaceable, so that when the energy stored in them is depleted, they can be replaced with freshly filled reservoir containers, in order to enable a substantially continuous operation of the redox flow battery according to the present invention. [Brief explanation of the drawings]

[0026] [Figure 1] 2A-2C are two views of one battery column that can be employed in a battery stack unit according to the present invention. [Figure 2] FIG. 1 shows a battery stack unit according to the present invention employing a plurality of battery columns shown in front view. [Figure 3] 3 is an isometric view of the battery stack unit of FIG. 2 with a portion of its battery core stack removed. [Figure 4] FIG. 4 is a schematic diagram of a redox flow battery according to the present invention employing the cell stack unit of FIGS. 2 and 3. DETAILED DESCRIPTION OF THE INVENTION

[0027] Further features and advantages of the present invention will become more apparent from the following description of the embodiments thereof taken in conjunction with the accompanying drawings.

[0028] 1 shows an isometric view and a schematic side view of a battery column used in a cell stack unit of a redox flow battery and including a plurality of individual battery core stacks 12, the battery column generally designated by the reference numeral 10. Here, each of the individual battery core stacks 12 similarly includes a plurality of battery cells stacked along a stacking direction S. Between each pair of adjacent battery core stacks 12, a respective connection element 14 including an electrical current collector is provided, which is surface-connected to the adjacent battery core stack 12 by alternately orienting the battery core stacks 12 with respect to their polarities within the battery column 10, so that the positive and negative terminals of each of the adjacent battery core stacks 12 face each other and can be surface-connected to a single connection element 14, reducing the amount of electrical wiring required. The connection element 14 may be divided into two functional units, each of which serves as a fixed stack enclosure for a given side of the core stack 12.

[0029] As can be seen in FIG. 1 , first and second end plates 16 a and 16 b are provided on the battery column 10 at both ends thereof in the stacking direction S, thereby enabling improved integration of the battery column 10 within a battery stack unit 20, as described below. As can be seen from the left side of FIG. 1 , the first end plate 16 a is further equipped with two pairs of branch lines 18 of the fluid system of the battery stack unit 20, which pass through the first end plate 16 a and enable the supply of two electrolyte solutions to each battery cell of each battery core stack 12 within the battery column 10. For this purpose, the individual battery core stacks 12 and the connection elements 14 themselves are also provided with fluid conduits that enable the propagation of the electrolyte solutions throughout the battery column 10. Corresponding fluid conduits 14 a provided on the visible connection elements 14 are also shown schematically in FIG. 1 .

[0030] For illustrative purposes, the schematic side view on the right side of Figure 1 shows only two battery core stacks 12 and three connection elements of the battery column 10. Here, arrows 12a indicate that a lightweight tensioning system is provided on each individual battery core stack 12 to absorb attachment forces into the respective core stack 12 and ensure the structural integrity of the core stack 12 outside the battery column, for example, before the battery column is inserted or in the case of replacement. Furthermore, the schematic side view shows protective element 14b, which is omitted in the isometric view on the left side of Figure 1 and which covers the connection elements 14 from above in the configuration shown in Figure 2 and described below. The stacking direction S corresponds to the horizontal direction, with multiple core stacks 12 positioned one above the other.

[0031] The protective elements 14b are sealed to the respective core stacks 12 and prevent fluids from contacting the connection elements 14 from above. Thus, the protective elements 14b act as a safety feature, particularly in the event that leakage of electrolyte solution occurs in one of the core stacks 12 of the battery column 10, the leakage may subsequently fall and cause damage, such as a short circuit, to one of the connection elements 14 of the battery column below. In response, the leaked electrolyte solution is directed away from the core stacks 12 and the connection elements 14 by suitable channels or grooves and into a recovery recess (not shown).

[0032] 2 and 3, a battery stack unit 20 is shown in a front view and an isometric view, respectively, with some battery core stacks removed in FIG. 3. As can be seen from FIGS. 2 and 3, in the battery stack unit 20, a total of four identical battery columns 10 are installed in parallel within a rack 22 extending on both sides of the battery columns 10 with respect to the stacking direction S of the battery columns 10. The rack 22 is configured as a frame extending around the battery columns 10, with the frame having two respective longitudinal sides 24 extending along the stacking direction S and first and second transverse sides 26 and 28 extending perpendicular to the stacking direction S. It can be seen that the first end plate 16a of each battery column 10 is fixedly mounted to the first transverse side 26 of the rack 22, while the second transverse side 28 is provided with a tensioning system 30 adapted to individually compress each second end plate 16b of the four battery columns 10 along the stacking direction S to compress the respective battery core stacks 12 within each battery column 10.

[0033] 3, in which a particular battery core stack 12 is removed, an individual battery core stack 12 can be removed from its respective battery column 10 and replaced in the event of a malfunction of one or more of its battery cells by loosening the tensioning system 30 for the corresponding battery column 10. The battery core stacks 12 may therefore be provided as self-contained modules, individually insertable into the rack 22 between the respective connection elements 14 and easily removable therefrom.

[0034] The core stack 12 of each battery column 10 can be positioned, moved, and guided to an end position by a system of rails or hanging gears, which are omitted from the drawing, to improve the visibility of the remaining components. To prevent damage caused by possible leakage in the event of a malfunction or accident or when replacing the core stack 12, a device for protecting the current collectors and terminal electrodes from leakage originating from the same battery column 10 or a protective cover may be installed as described above. This improves maintainability and increases the expected lifespan of the battery column 10.

[0035] 2 and 3, the cell stack unit 20 further comprises two pumps 32, one for each of the two solutions supplied to the individual battery cells. For this purpose and to guide the solutions to the branch lines 18 already mentioned above, the fluid system of the cell stack unit 20 further comprises a pair of manifold lines, one for each of the two electrolyte solutions, each of the pairs also comprising a feed line and a return line. The manifold line pairs are arranged in a fluid supply unit 34 attached to the first transverse surface 26 of the rack 22 and are individually connected to all of the branch lines 18 as shown in FIGS. 2 and 3.

[0036] 2 and 3, but as already briefly mentioned above, the cell stack unit 20 may further comprise, as part of its fluid system, a collection recess for leaked electrolyte solution and a leak sensor provided in the collection recess or in any other suitable position in the cell stack unit 20 where a possible leak can be detected. The fluid system may also further comprise at least one additional sensor unit, such as a pressure sensor and / or a temperature sensor, which may be provided, for example, in one of the manifold lines in the fluid supply unit 34, and / or the fluid system may comprise, for example, a heat exchanger, for increasing the thermal efficiency of the cell stack unit 20, as part of the fluid supply unit 34.

[0037] As well as the fluid system adapted to supply the battery cells with two types of energy storage electrolyte solutions, the cell stack unit 20 is also provided with an electrical system 36 adapted to output the electrical power generated by the individual battery cells, which comprises pairs of bus bars 38 extending along the stacking direction S of the core stacks 12, by means of which each core stack 12 is connected from below by dedicated current collectors 40 and at their output faces connected to power electronic components (not shown).

[0038] Finally, in Figure 4 a schematic diagram of a redox flow battery 100 is given, comprising the cell stack unit 20 of Figures 2 and 3 as its central piece. The battery 100 further comprises two reservoir containers 102 for storing electrolyte solutions coupled to the fluid system of the cell stack unit 20 and in particular to the pump 32 and its fluid supply unit 34. Still further, a control unit 104 is provided which controls the operation of the cell stack unit 20, for example by appropriately operating the pump 32 and receiving output data of any sensor units provided in the cell stack unit 20 and monitoring its operation.

Claims

1. A cell stack unit (20) for a redox flow battery (100), comprising: a plurality of battery core stacks (12), each similarly comprising a plurality of battery cells, stacked along a stacking direction (S) to form at least one battery column (10), connected within the at least one battery column (10) by connection elements (14), the connection elements being provided between pairs of the core stacks (12), the battery cells being adapted to generate electricity through a redox reaction of two types of energy storage electrolyte solutions; a rack (22) extending on both sides of the at least one battery column (10) in the stacking direction (S), the rack (22) being provided with at least one first end plate (16a), the first end plate being arranged to support the at least one battery column (10) at a first end in the stacking direction (S); a tensioning system (30) provided on the rack (22), the tensioning system (30) adapted to pull the at least one battery column (10) toward the first end plate (16a) at a second end of the battery column with respect to the stacking direction (S) by at least one second end plate (16b); a fluid system adapted to supply two energy storage electrolyte solutions to the battery cells from respective reservoir containers (102); an electrical system (36) adapted to output the electrical power generated in the battery cell; A battery stack unit (20) comprising:

2. The battery stack unit (20) according to claim 1, wherein the stacking direction (S) of the at least one battery column (10) corresponds to a substantially horizontal or vertical direction.

3. The battery stack unit (20) according to claim 1 or 2, wherein the battery core stack (12) is configured as a built-in module that can be individually inserted into the rack (22).

4. The battery stack unit (20) according to any one of claims 1 to 3, wherein one respective first and / or second end plate (16a, 16b) is provided for each battery column (10).

5. The fluid system comprises: a respective pair of manifold lines (34) for each of the two electrolyte solutions, each of the pairs comprising a feed line and a return line; a respective pair of branch lines (18) for each of the two electrolyte solutions and each battery column (10); The battery stack unit (20) according to any one of claims 1 to 4, comprising:

6. 6. The battery stack unit (20) of claim 5, wherein each of the pair of branch lines (18) of the battery column passes through the at least one first end plate (16a).

7. 6. The battery stack unit (20) according to claim 5, wherein the pair of branch lines are guided outside the at least one battery column, and preferably each of the core stacks is individually connected to the respective branch line.

8. The cell stack unit (20) according to any one of claims 1 to 7, wherein the fluid system comprises a respective pump (32) for each of the two electrolyte solutions.

9. 9. The cell stack unit (20) according to any one of claims 1 to 8, wherein the fluid system further comprises a recovery recess for leaked electrolyte solution, preferably the recovery recess being provided with a leakage sensor.

10. the fluid system preferably comprises at least one sensor unit, such as a pressure sensor and / or a temperature sensor, provided in one of the manifold lines, and / or the fluid system comprises a heat exchanger; At least one of the core stacks (12) is provided with at least one current and / or voltage sensor; and / or The battery stack unit (20) according to any one of claims 1 to 9, wherein the battery stack unit (20) comprises at least one structure-borne sound sensor.

11. The battery stack unit (20) of any one of claims 1 to 10, wherein the core stacks (12) within a battery column (10) are oriented with alternating opposite polarities.

12. 12. The battery stack unit (20) according to claim 1, wherein the electrical system (36) comprises at least a pair of bus bars (38) extending along the stacking direction (S), and the pair of bus bars connects each of the core stacks (12) or groups of core stacks (12) connected in series, preferably from below.

13. the rack (22) is configured as a frame extending around the at least one battery column and having two longitudinal sides (24) extending along the stacking direction (S) and two transverse sides (26, 28) extending perpendicular thereto, one of the two transverse sides (26) being provided with the at least one first end plate (16a) and the other of the two transverse sides (28) being provided with the tensioning system (30); and / or The battery stack unit (20) according to any one of claims 1 to 12, wherein the rack (22) is provided with attachment points for moving the battery stack unit (20), for example, by an external crane.

14. All of the battery cells are formed substantially identically, and / or the effective area of ​​at least one of the battery cells in a cross section with respect to the stacking direction (S) is 2500 cm ２ Below, especially 1000 cm ２ The battery stack unit (20) according to any one of claims 1 to 13, wherein:

15. A battery stack unit (20) according to any one of claims 1 to 14; At least two reservoir containers (102) for an energy storage electrolyte solution, coupled to the fluid system of the battery stack unit; a control unit (104) adapted to control and / or monitor the operation of the redox flow battery (100); A redox flow battery (100) comprising:

Images