CA3182832A1 - A universal frame for a redox flow battery stack - Google Patents

Abstract

A universal frame for a redox flow battery stack has a frame with a front frame and a back frame. The frame has an input port, an outlet port, and at least one flow chamber in fluid communication with the input port and outlet port. The at least one flow chamber is positioned in an interior of the frame. An interior surface of front frame and back frame has an input electrolyte flow channel in communication with the input port and an output electrolyte flow channel in fluid communication with the outlet port. The input electrolyte flow channel and the output electrolyte flow channel in fluid communication with the at least one flow chamber. Interior channel covers contact the interior surface of the front frame and the back frame to cover the input and output electrolyte flow channels. A membrane is held between the front frame and the back frame.

Description

TITLE
[0001] A Universal Frame for a Redox Flow Battery Stack FIELD OF THE DISCLOSURE

[0002] The present application relates generally to a frame for a redox flow battery stack.
BACKGROUND

[0003] This section provides background information to facilitate a better understanding of the various aspects of the invention. It should be understood that the statements in this section of this document are to be read in this light, and not as admissions of prior art.

[0004] Redox flow batteries are a type of rechargeable battery that utilizes ion transfer inside of cells to recharge and discharge electricity. Flow batteries may be used like fuel cells or like rechargeable batteries. While other carriers may be used, vanadium ions are commonly used as charge carriers.
Redox flow batteries tend to have a number of advantages over conventional rechargeable batteries including independent scaling of power and energy by altering stack size, long cycle and calendar lives, potentially lower cost.
BRIEF SUMMARY

[0005] There is provided a universal frame for a redox flow battery stack that has a frame. The frame has a front frame and a back frame. The frame has an input port that extends through the front frame to the back frame and an outlet port that extends through the front frame to the back frame. At least one flow chamber is provided in fluid communication with the input port and the outlet port. The at least one flow chamber is positioned in an interior of the frame. The interior surface of each of the front frame and the back frame has an input electrolyte flow channel and an output electrolyte flow channel.
The at least one flow chamber is in fluid communication with the input electrolyte flow channel and the output electrolyte flow channel. The input electrolyte flow channel is in fluid communication with the input port and the output electrolyte flow channel is in fluid communication with the outlet port. A first Date Regue/Date Received 2022-11-29 felt is positioned interior to and adjacent the front frame and a second felt is positioned interior to and adjacent the back frame. The first felt and the second felt are sized such that each of the first felt and the second felt correspond in size to the at least one flow chamber. A first interior channel cover is positioned interior to the front frame. The first interior channel cover has a first flow chamber cutout sized to correspond to the size of the flow chamber. The first interior channel cover contacts the interior surface of the front frame such that the input electrolyte flow channel and the output electrolyte flow channel are covered. A second interior channel cover is positioned interior to the back frame. The second interior channel cover has a second flow chamber cutout sized to correspond to the size of the flow chamber. The second interior channel cover contacts the interior surface of the back frame such that the input electrolyte flow channel and the output electrolyte flow channel are covered. A
membrane is positioned centrally between the first interior channel cover and the second interior channel cover. The membrane is in contact with the first felt and the second felt. The membrane acts as an ion exchange membrane such that free electrons pass from a first side to a second side to create an electric charge between a negative and a positive electrolyte.

[0006] In one embodiment, the at least one flow chamber is divided into at least two portions by at least one chamber separator.

[0007] In one embodiment, at least two flow equalizer slots are positioned between the input electrolyte flow channel and the at least one flow chamber. The size of the flow equalizer slots may be uniform or may vary.

[0008] In one embodiment, the at least two flow equalizer slots positioned between the input electrolyte flow channel and the at least one flow chamber are sized such that the flow equalizer slots having the shortest distance of fluid travel from the input port are smaller in size than the flow equalizer slots having the longest distance of fluid travel from the input port, each of the at least two flow equalizer slots increasing in size as the distance of fluid travel from the input port increases and decreasing in size as the distance of fluid travel from the input port decreases.

[0009] In another embodiment, the at least flow equalizer slots are sized such that the at least two flow equalizer slots increase in size as the at least two flow equalizers are positioned closer to a central point Date Regue/Date Received 2022-11-29 of the frame and the at least two flow equalizers decrease in size as the at least two flow equalizers are positioned towards an edge of the frame.

[0010] In one embodiment, at least two flow equalizer slots are positioned between the output electrolyte flow channel and the at least one flow chamber. The size of the flow equalizer slots may be uniform or may vary.

[0011] In one embodiment, the at least two flow equalizer slots positioned between the output electrolyte flow channel and the at least one flow chamber are sized such that the flow equalizer slots having the shortest distance of fluid travel to the output port are smaller in size than the flow equalizer slots having the longest distance of fluid travel to the output port, each of the at least two flow equalizer slots increasing in size as the distance of fluid travel to the output port increases and decreasing in size as the distance of fluid travel to the output port decreases.

[0012] In another embodiment, the at least flow equalizer slots are sized such that the at least two flow equalizer slots increase in size as the at least two flow equalizers are positioned closer to a central point of the frame and the at least two flow equalizers decrease in size as the at least two flow equalizers are positioned towards an edge of the frame.

[0013] In one embodiment, the input electrolyte flow channel is positioned opposite to the at least one flow chamber to the output electrolyte flow channel.

[0014] In one embodiment, the frame has an input flow connection extending through the front frame and the back frame for creating a fluid connection to a second frame.

[0015] In one embodiment, the frame has an output flow connection extending through the front frame and the back frame for creating a fluid connection to a second frame.

[0016] In one embodiment, a seal is provided along a flow path created between the input port and the outlet port. The seal seals the front frame to the first interior channel cover and the seal sealing the back frame to the second interior channel cover.

[0017] In one embodiment, a bipolar recess is positioned on exterior surface of each of the front frame and the back frame for maintaining the position of a bipolar plate in relation to the frame.

Date Regue/Date Received 2022-11-29

[0018] In one embodiment, a bipolar seal is provided to seal between the exterior surface of each of the front frame and the back frame of the frame and the bipolar plate.

[0019] In one embodiment, a plurality of rod holes are provided along a periphery and through the frame for stacking at least two frames together.

[0020] In one embodiment, an input fluid flow is divided into a first input stream and a second input stream by an input notch. The input notch being positioned on a central point of an input longitudinal divider. The input longitudinal divider divides the input electrolyte flow channel into an input upper portion and an input lower portion such that the fluid flow continues around a first end and a second end of the input longitudinal divider.

[0021] In one embodiment, the at least two flow equalizer slots positioned between the input electrolyte flow channel and the at least one flow chamber are sized such that the at least two flow equalizer slots increase is size as the at least two flow equalizers are positioned closer to the input notch and the at least two flow equalizers decrease in size as the at least two flow equalizers are positioned towards an edge of the frame.

[0022] In one embodiment, an input fluid flow is divided into a first outlet stream and a second outlet stream by an outlet notch. The outlet notch being positioned on a central point of an outlet longitudinal divider. The outlet longitudinal divider divides the outlet electrolyte flow channel into an outlet upper portion and an outlet lower portion such that the fluid flow continues around a first end and a second end of the outlet longitudinal divider.

[0023] In one embodiment, the at least two flow equalizer slots positioned between the outlet electrolyte flow channel and the at least one flow chamber are sized such that the at least two flow equalizer slots increase in size as the at least two flow equalizers are positioned closer to the outlet notch and the at least two flow equalizers decrease in size as the at least two flow equalizers are positioned towards an edge of the frame.

[0024] In one embodiment, the at least two flow equalizer slots positioned between the input electrolyte flow channel and the at least one flow chamber are mirrored by the at least two flow Date Regue/Date Received 2022-11-29 equalizer slots positioned between the outlet electrolyte flow channel and the at least one flow chamber.
BRIEF DESCRIPTION OF THE DRAWINGS

[0025] These and other features will become more apparent from the following description in which references are made to the following drawings, in which numerical references denote like parts. The drawings are for the purpose of illustration only and are not intended to in any way limit the scope of the invention to the particular embodiments shown.

[0026] FIG. 1 is a perspective view of the interior surface of the front frame and the back frame.

[0027] FIG. 2 is a perspective view of an exterior surface of the front frame and the back frame.

[0028] FIG. 3 is an exploded view of the frame.

[0029] FIG. 4 is an exploded view of a stack of frames.

[0030] FIG. 5 is a perspective view of the input electrolyte flow channel.

[0031] FIG. 6 is a perspective view of the outlet electrolyte flow channel.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] A universal frame for a redox flow battery stack, generally identified by reference numeral 10, will now be described with reference to FIG. 1 through FIG. 6.

[0033] Referring to FIG. 3, a universal frame 10 for a redox flow battery stack has a frame 12. Frame 12 has a front frame 14 and a back frame 16 that are fixedly attached to each other. Frame 12 has an input port 18 that extends through front frame 14 to back frame 16 and an output port 20 that extends through front frame 14 to back frame 16. Flow chamber 22 is provided in fluid communication with input port 18 and outlet port 20. Referring to FIG. 1, flow chamber 22 is positioned in an interior of frame 12 such that flow chamber 22 extends into both front frame 14 and back frame 16. In the embodiment shown, there is a single flow chamber 22 that is divided into three portions 22a, 22b, and 22c by two chamber separators 23a and 23b. It will be understood by a person skilled in the art that multiple flow chambers 22 may be included within frame 12 and each flow chamber 22 may be divided into multiple portions by chamber separators.

Date Regue/Date Received 2022-11-29

[0034] Referring to FIG. 2, front frame 14 and back frame 16 each have an input electrolyte flow channel 24 and an output electrolyte flow channel 26 positioned in an interior surface 21. Flow chamber 22 is in fluid communication with input electrolyte flow channel 24 and output electrolyte flow channel 26. Input electrolyte flow channel 24 is in fluid communication with input port 18 and output electrolyte flow channel 26 is in fluid communication with output port 20. In the embodiment shown, input electrolyte flow channel 24 is positioned adjacent a top 25 of front frame 14 and back frame 16 and output electrolyte flow channel 26 is positioned opposite to input electrolyte flow channel 26 by being positioned adjacent a bottom 27 of front frame 14 and back frame 16. It will be understood by a person skilled in the art that input electrolyte flow channel 24 may be positioned adjacent top 25, bottom 27, or either peripheral edge 29a and 29b and output electrolyte flow channel 26 may be positioned adjacent top 25, bottom 27, or either peripheral edge 29a and 29b but may not be positioned in the same place as input electrolyte flow channel 26.

[0035] Referring to FIG. 3, frame 12 has a first felt 66 and a second felt 68.
First felt 66 is positioned interior to and adjacent front frame 14 and second felt 68 is positioned interior to and adjacent back frame 16. First felt 66 and second felt 68 are each sized such that first felt 66 and second felt 68 correspond in size to flow chamber 22. A first interior channel cover 70 is positioned interior to front frame 14. First interior channel cover 70 has a first flow chamber cutout 72 sized to correspond to the size of flow chamber 22. First interior channel cover 70 contacts interior surface 21 of front frame 14 such that input electrolyte flow channel 24 and output electrolyte flow channel 26 are covered. A
second interior channel cover 74 is positioned interior to back frame 16.
Second interior channel cover 74 has a second flow chamber cutout 76 sized to correspond to the size of flow chamber 22. Second interior channel cover 74 contacts interior surface 21 of back frame 16 such that input electrolyte flow channel 24 and output electrolyte flow channel 26 are covered. A membrane 78 is positioned centrally between first interior channel cover 70 and second interior channel cover 74.
Membrane 78 is in contact with first felt 66 and second felt 68. Membrane 78 acts as an ion exchange membrane such that free electrons pass from a first side 80 to a second side 82 to create an electric charge between a negative and a positive electrolyte.

[0036] First felt 66 and second felt 68 are preferably made of carbon fiber which allows electrolyte to spread over membrane 78 and transfer free electrons to bipolar plate 48 in contact with first felt 66 or Date Regue/Date Received 2022-11-29 second felt 68. One of first interior channel cover 70 and second interior channel cover 74 may have a cutout 84 to allow for attachment of membrane 78. Membrane 78 is sandwiched between first interior channel cover 70 and second interior channel cover 74 to help create a barrier between positive and negative electrolyte within frame 12.

[0037] Flow equalizer slots 28 may be positioned between input electrolyte flow channel 24 and flow chamber 22. Flow equalizer slots 28 may also be positioned between output electrolyte flow channel 26 and flow chamber 22. Flow equalizer slots 28 are designed to equalize flow distribution across the entire width of flow chamber 22, including portions 22a, 22b, and 22c when flow chamber 22 is separated by chamber separators 23a and 23b. It will be understood by a person skilled in the art that the number of flow equalizer slots 28 may vary depending upon user preferences, however at least two flow equalizer slots 28 are required. In the embodiment shown, flow equalizer slots 28 are sized such that the size of flow equalizer slots 28 increases as the flow equalizer slots 28 are positioned closer to a central point 30 of frame 12 and decrease in size as flow equalizer slots 28 are positioned towards peripheral edges 29a and 29b of frame 12. Flow equalizer slots 28 are designed to help create a uniform flow across the entire width of flow chamber 22 between input electrolyte flow channel 24 and flow chamber 22 and outlet electrolyte flow channel 26 and flow chamber 22.

[0038] Referring to FIG. 5, in the embodiment shown, input fluid flow may be divided into a first input streams 31a and a second input stream 31b by an input notch 32. Input notch 32 is positioned on a central point of an input longitudinal divider 33. Input longitudinal divider 33 divides input electrolyte flow channel 24 into an upper portion 35 and a lower portion 37 such that fluid flow continues around a first end 39 and a second end 41 of the input longitudinal divider 33. Flow equalizer slots 28 may be sized such that the size of flow equalizer slots 28 having the shortest distance of fluid travel from input port 18 are smaller in size than flow equalizer slots 28 having the longest distance of fluid travel from input port 18. The smallest flow equalizer slots 28 have the shortest distance of fluid travel from input port 18 and each consecutive flow equalizer slot 28 increases in size as the distance of fluid travel from input port 18 increases. In the embodiments shown, the distance of fluid travel from input port 18 is shortest adjacent peripheral edges 29a and 29b of frame 12 and the distance of fluid travel increases towards a center of frame 12, the center of frame corresponding to the positioning of notch 32 in lower portion 37 of input electrolyte flow channel 24. Flow equalizer slots 28 are sized such that the size of flow equalizer slots 28 closer to input notch 32 are smaller in size than those flow equalizer slots 28 positioned towards peripheral edges 29a and 29b of frame 12. The smallest flow equalizer slot 28 is Date Regue/Date Received 2022-11-29 adjacent input notch 32 with each consecutive flow equalizer slot 28 increasing in size as the distance to input notch 32 increases. It will be understood by a person skilled in the art that the size of flow equalizer slots 28 and the amount of size increase may be based upon user preferences.

[0039] In the embodiment shown in FIG. 6, outlet fluid flow is divided into a first outlet stream 43a and a second outlet stream 43b by an outlet notch 45. Outlet notch 45 is positioned on a central point of an outlet longitudinal divider 47. Outlet longitudinal divider 47 divides outlet electrolyte flow channel 26 into an upper section 49 and a lower portion 51 such that fluid flow continues around a first end 53 and a second end 54 of the outlet longitudinal divider 47. Flow equalizer slots 28 may be sized such that the size of flow equalizer slots 28 having the shortest distance of fluid travel to output port 20 are smaller in size than flow equalizer slots 28 having the longest distance of fluid travel to output port 20. The smallest flow equalizer slots 28 have the shortest distance of fluid travel to output port 20 and each consecutive flow equalizer slot 28 increases in size as the distance of fluid travel to output port 20 increases. In the embodiments shown, the distance of fluid travel to output port 20 is shortest adjacent peripheral edges 29a and 29b of frame 12 and the distance of fluid travel increases towards a center of frame 12, the center of frame corresponding to the positioning of outlet notch 45 in lower portion 51 of output electrolyte flow channel 26. Flow equalizer slots 28 are sized such that the size of flow equalizer slots 28 closer to outlet notch 45 are smaller in size than those flow equalizer slots 28 positioned towards peripheral edges 29a and 29b of frame 12. The smallest flow equalizer slot 28 is adjacent outlet notch 45 with each consecutive flow equalizer slot 28 increasing in size as the distance to outlet notch 45 increases. It will be understood by a person skilled in the art that the size of flow equalizer slots 28 and the amount of size increase may be based upon user preference.

[0040] In the embodiment shown in FIG. 1, flow equalizer slots 28 positioned between input electrolyte .. flow channel 24 and flow chamber 22 are mirrored by flow equalizer slots 28 positioned between outlet electrolyte flow channel 26 and flow chamber 22.

[0041] Referring to FIG. 1 and 2, when multiple frames 12 are stacked together, an input flow connection 34 and an output flow connection 36 may be provided to create a fluid connection between adjacent frames 12, shown in FIG. 4. Referring to FIG. 3, input flow connection 34 extends through front frame 14 and back frame 16 to facilitate the flow of fluid between stacked frames 12. Input flow connection 34 of first frame 12 may be fluidly connected to input port 18 of second frame 12. Output Date Regue/Date Received 2022-11-29 flow connection 36 extends through front frame 14 and back frame 16 to facilitate the flow of fluid between stacked frames 12. Output flow connection 36 of first frame 12 may be fluidly connected to output port 20 of second frame 12.

[0042] Referring to FIG. 3, to help prevent leaks of fluid out of frame 12, a seal 38 is provided along the length of a flow path 40 that is created between input port 18 and output port 20. Seal 38 seals interior surface 21 of front frame 14 to first interior channel cover 70 and seals interior surface 21 of back frame 16 to second interior channel cover 74.

[0043] Referring to FIG. 2, a bipolar recess 44 may be positioned on an exterior surface 46 of each of front frame 14 and back frame 16 for assisting in maintaining the position of a bipolar plate 48, shown in FIG. 4, in relation to frame 12. A bipolar seal 50 may also be provided to create a seal between bipolar recess 44 on exterior surface 46 of front frame 14 or back frame 16 and bipolar plate 48.

[0044] Referring to FIG. 4, when a stack of frames 12 is created, rods 50 may be used to position frames 12 in a fixed relation relative to each other. Rods 50 may pass through rod holes 52 provided along a periphery of frame 12. Rods 50 are held in place by washers 56 and nuts 58. It will be understood by a person skilled in the art that the number of rods 50 and rod holes 52 that are used may vary based upon user preference. Generally, the use of multiple rods and rod holes 52 will result in a more robust stack than using a single rod 50 and rod hole 52 when stacking at least two frames together. In the embodiment shown, five frames 12 are stacked together between a pair of end caps 60 and end cap doors 62. A current collector 64 is positioned adjacent to each of end caps 60 and in contact with end cap doors 62. Bipolar plate 48 is positioned adjacent the first frame 12 in the stack and in contact with one of the current collectors 64. Current collectors 64 allow electrical current to travel into and out of stack of frames 12.

[0045] Any use herein of any terms describing an interaction between elements is not meant to limit the interaction to direct interaction between the subject elements, and may also include indirect interaction between the elements such as through secondary or intermediary structure unless specifically stated otherwise.

[0046] In this patent document, the word "comprising" is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded. A

Date Regue/Date Received 2022-11-29 reference to an element by the indefinite article "a" does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one of the elements.

[0047] It will be apparent that changes may be made to the illustrative embodiments, while falling within the scope of the invention. As such, the scope of the following claims should not be limited by the preferred embodiments set forth in the examples and drawings described above, but should be given the broadest interpretation consistent with the description as a whole.
Date Regue/Date Received 2022-11-29

Claims (20)

What is claimed is:

1. A universal frame for a redox flow battery stack, comprising:
a frame having a front frame and a back frame, the frame having an input port that extends through the front frame to the back frame, an outlet port that extends through the front frame to the back frame, and at least one flow chamber in fluid communication with the input port and the outlet port, the at least one flow chamber being positioned in an interior of the frame;
each of the front frame and the back frame having an input electrolyte flow channel and an output electrolyte flow channel positioned in an interior surface, the at least one flow chamber being in fluid communication with the input electrolyte flow channel and the output electrolyte flow channel, the input electrolyte flow channel being in fluid communication with the input port, and the output electrolyte flow channel being in fluid communication with the output port;
a first felt positioned interior to and adjacent the front frame and a second felt positioned interior to and adjacent the back frame; the first felt and the second felt being sized such that each of the first felt and the second felt correspond in size to the at least one flow chamber;
a first interior channel cover positioned interior to the front frame, the first interior channel cover having a first flow chamber cutout sized to correspond to the size of the flow chamber, the first interior channel cover contacting the interior surface of the front frame such that the input electrolyte flow channel and the output electrolyte flow channel are covered;
a second interior channel cover positioned interior to the back frame, the second interior channel cover having a second flow chamber cutout sized to correspond to the size of the flow chamber, the second interior channel cover contacting the interior surface of the back frame such that the input electrolyte flow channel and the output electrolyte flow channel are covered;
a membrane positioned centrally between the first interior channel cover and the second interior channel cover, the membrane being in contact with the first felt and the second felt, the membrane acting as an ion exchange membrane such that free electrons pass from a first side to a second side to create an electric charge between a negative and a positive electrolyte.

2. The universal frame for a redox flow battery stack of claim 1 wherein the at least one flow chamber is divided into at least two portions by at least one chamber separator.

Date Regue/Date Received 2022-11-29

3. The universal frame for a redox flow battery stack of claim 1 wherein at least two flow equalizer slots are positioned between the input electrolyte flow channel and the at least one flow chamber.

The universal frame for a redox flow battery stack of claim 3 wherein the at least two flow equalizer Its positioned between the input electrolyte flow channel and the at least one flow chamber are sized ch that the size of the flow equalizer slots having the shortest distance of fluid travel from the input rt are smaller in size than the flow equalizer slots having the longest distance of fluid travel from the )ut port, each of the at least two flow equalizer slots increasing in size as the distance of fluid travel )m the input port increases and decreasing in size as the distance of fluid travel from the input port creases.

The universal frame for a redox flow battery stack of claim 3 wherein the at least two flow equalizer Its positioned between the input electrolyte flow channel and the at least one flow chamber are sized ch that the at least two flow equalizer slots increase in size as the at least two flow equalizer slots are sitioned closer to a central point of the frame and the at least two flow equalizers decrease in size as ?. at least two flow equalizers are positioned towards an edge of the frame.

The universal frame for a redox flow battery stack of claim 1 wherein at least two flow equalizer slots ?. positioned between the output electrolyte flow channel and the at least one flow chamber.

The universal frame for a redox flow battery stack of claim 6 wherein the at least two flow equalizer Its positioned between the output electrolyte flow channel and the at least one flow chamber are ed such that the size of the flow equalizer slots having the shortest distance of fluid travel to the tput port are smaller in size than the flow equalizer slots having the longest distance of fluid travel to ?. output port, each of the at least two flow equalizer slots increasing in size as the distance of fluid ivel to the output port increases and decreasing in size as the distance of fluid travel to the output rt decreases.

The universal frame for a redox flow battery stack of claim 6 wherein the at least two flow equalizer sluts positioned between the output electrolyte flow channel and the at least one flow chamber are sized such that the at least two flow equalizers increase in size as the at least two flow equalizers are Date Regue/Date Received 2022-11-29 positioned closer to a central point of the frame and the at least two flow equalizers decrease in size as the flow equalizers are positioned towards an edge of the frame.

9. The universal frame for a redox flow battery stack of claim 1 wherein the input electrolyte flow channel is positioned opposite to the at least one flow chamber to the output electrolyte flow channel.

10. The universal frame for a redox flow battery stack of claim 1 wherein the frame has an input flow connection extending through the front frame and the back frame for creating a fluid connection to a second frame.

11. The universal frame for a redox flow battery stack of claim 1 wherein the frame has an output flow connection extending through the front frame and the back frame for creating a fluid connection to the second frame.

12. The universal frame for a redox flow battery stack of claim 1 wherein a seal is provided along a flow path created between the input port and the outlet port, the seal sealing the front frame to the first interior channel cover and the seal sealing the back frame to the second interior channel cover.

13. The universal frame for a redox flow battery stack of claim 1 wherein a bipolar recess is positioned on an exterior surface of each of the front frame and the back frame for maintaining the position of a bipolar plate in relation to the frame.

14. The universal frame for a redox flow battery stack of claim 1 wherein a bipolar seal is provided to seal between the exterior surface of each of the front frame and the back frame of the frame and the bipolar plate.

15. The universal frame for a redox flow battery stack of claim 1 wherein a plurality of rod holes are provided along a periphery and through the frame for stacking at least two frames together.

16. The universal frame for a redox flow battery stack of claim 1 wherein an input fluid flow is divided into a first input stream and a second input stream by an input notch, the input notch being positioned on a central point of an input longitudinal divider, the input longitudinal divider dividing the input Date Regue/Date Received 2022-11-29 electrolyte flow channel into an input upper portion and an input lower portion such that the fluid flow continues around a first end and a second end of the input longitudinal divider.

17. The universal frame for a redox flow battery stack of claim 16 wherein the at least two flow equalizer slots positioned between the input electrolyte flow channel and the at least one flow chamber are sized such that the at least two flow equalizer slots increase in size as the at least two flow equalizers are positioned closer to the input notch and the at least two flow equalizers decrease in size as the at least two flow equalizers are positioned towards an edge of the frame.

18. The universal frame for a redox flow battery stack of claim 16 wherein an outlet fluid flow is divided into a first outlet stream and a second outlet stream by an outlet notch, the outlet notch being positioned on a central point of an outlet longitudinal divider, the outlet longitudinal divider dividing the outlet electrolyte flow channel into an outlet upper portion and an outlet lower portion such that the fluid flow continues around a first end and a second end of the outlet longitudinal divider.

19. The universal frame for a redox flow battery stack of claim 18 wherein the at least two flow equalizer slots positioned between the outlet electrolyte flow channel and the at least one flow chamber are sized such that the at least two flow equalizer slots increase in size as the at least two flow equalizers are positioned closer to the outlet notch and the at least two flow equalizers decrease in size as the at least two flow equalizers are positioned towards an edge of the frame.

20. The universal frame for a redox flow battery stack of claim 19 wherein the at least two flow equalizer slots positioned between the input electrolyte flow channel and the at least one flow chamber are mirrored by the at least two flow equalizer slots positioned between the outlet electrolyte flow channel and the at least one flow chamber.