DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 1-5 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Regarding claim 1, the recitation "plurality of canals of different depths" is indefinite because the specification provides no definition, boundaries, or objective standard for measuring these "depths" in a carbon-felt medium. The specification also fails to describe any etching process or parameter configurations capable of introducing variable depth characteristics to individual canals. This leaves the metes and bounds of the claim unclear; under a Broadest Reasonable Interpretation (BRI), a person of ordinary skill in the art (PHOSITA) would not be able to determine the boundaries of the claimed "different depths," particularly since the application's sole visual disclosure of this feature is a single figure (Fig. 3) showing an interdigitated configuration that appears visually uniform and planar. Because the metes and bounds of the variable depth limitation cannot be reasonably ascertained from the disclosure, the claim is indefinite. Appropriate correction is required.
Claim 1 further recites, “…and two connecting collector plates to provide external power which enters through said anode collector plate and said cathode collector plate, conducts said carbon-felt electrodes through said bipolar plates, and is used to process electrochemical redox with said cathode electrolyte and said anode electrolyte.”
This limitation is indefinite because the structural relationship, electrical path, and functional cooperation of the "two connecting collector plates" within the claimed power distribution and redox process are unclear and ambiguous. The claim language states that external power "enters through said anode collector plate and said cathode collector plate, conducts said carbon-felt electrodes through said bipolar plates..." which routes the current path directly through the anode/cathode collector plates, carbon felt, and bipolar plates. The claim fails to clarify what role the "two connecting collector plates" play in this pathway, despite introducing them as components "to provide external power." The specification provides no mechanical, electrical, or functional disclosure detailing how the two connecting collector plates operate to provide external power, nor how they interface with the electrolytes or the adjacent components in the stack. Therefore, the boundaries of the claim cannot be determined because one of ordinary skill in the art is left to speculate how these two additional connecting plates physically connect to the external power source, the anode/cathode collector plates, or the stack itself to facilitate the electrochemical redox reaction. For the purposes of examination, the Examiner interprets the limitation "two connecting collector plates..." as structurally distinct, additional plate elements situated within the battery stack.
Claims 2-5 are rejected by dependency.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 1-5 are rejected under 35 U.S.C. 103 as being unpatentable over Bhattarai (WO2022093117A1) and further in view of Hao (Hao et. al., Regulating flow field design on carbon felt electrode towards high power density operation of vanadium flow batteries. Chemical Engineering Journal, Volume 450, Part 2, (2022).), Nakaishi 2004 (US20040241544A1), Nakaishi 2008 (US20080081247A1), Soo (KR20200072822A), and Baddeloo (US20230187652A1).
Regarding claim 1, Bhattarai teaches:
A flow battery stack (redox flow battery stack, specification pg. 3 lines 5-16; Figs. 2-3) with a plurality of felt electrodes (first and second felt electrodes 36, specification, pg. 3 lines 5-16; Fig. 3).
However, Bhattarai does not expressly disclose that the plurality of felt electrodes are specifically carbon-felt electrodes, nor does Bhattarai expressly disclose wherein each said carbon-felt electrode is etched with a plurality of canals of different depths.
Hao teaches the regulation of flow field design on carbon felt to achieve high-performance vanadium flow batteries (pg. 2, col. 1, para. 2 lines 1-2). Specifically, Hao teaches that designing parallel or interdigitated flow fields (i.e., canals) on a carbon-felt electrode substantially reduces pressure drops, provides a well-distributed reactant flow, and promotes electrolyte velocity across the porous electrode, thereby mitigating concentration polarization at high current densities (pg. 2, col. 1, para. 2).
Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to modify the felt electrode of Bhattarai by both utilizing the carbon-felt material and etching interdigitated flow fields/canals, as taught by Hao, in order to optimize the flow dynamics and efficiency of the battery stack. Implementing the interdigitated canals of Hao onto the felt electrodes of Bhattarai would predictably reduce pressure drop, enhance the local mass transfer coefficient, and mitigate concentration polarization at high current densities, with the predictable result of a highly efficient flow battery stack.
Regarding the limitation of a plurality of canals of "different depths," consistent with the 112(b) rejection above, it is noted that the Applicant’s specification does not define "depth," provide critical threshold limitations, or describe a specific etching process necessary to achieve a distinct depth variation. Under the Broadest Reasonable Interpretation (BRI) consistent with the specification, the term "etched" is interpreted broadly to encompass any material removal or groove-line forming that results in fluid channels, and "depth" is interpreted according to its ordinary dictionary definition as the measurement from the top surface downward. Furthermore, the Applicant’s specification relies on a drawing of the carbon-felt electrode (Fig. 3) to depict this feature, which appears visually identical to the interdigitated canal configuration explicitly illustrated in Fig. 2 of Hao. Because the structural layout of the interdigitated canals in Hao matches the Applicant's disclosure, the flow fields of Hao inherently possess depths measured from the electrode surface. To the extent that the canals in Hao are formed into a fibrous felt matrix, variations in depth are either inherently present due to the non-uniform topography of porous felt or represent a matter of routine optimization. Modifying the depth of a fluid canal to tune pressure drops and mass transport coefficients is a well-known design variable in the art of flow batteries. Bhattarai further teaches:
two fastening parts (end plates 22, [0014]; Figs. 2-3), wherein each said fastening part is provided with a plurality of hanging holes (see annotated Fig. 3 below).
However, modified Bhattarai does not expressly teach wherein each of the two fastening parts (i.e. end plates) are provided with a plurality of springs.
Nakaishi 2004 discloses a cell stack for a redox flow battery (claim 1) that comprises a clamping mechanism for holding the cell frames and the electrodes in sandwich relation between both of the end plates ([0019]). Nakaishi 2004 further teaches that the clamping mechanism of the cell stack includes elastic members disposed around the outside of the rod-like members between the nuts of the clamping mechanism and the end plates for absorbing expansion and contraction of the cell stack ([0021]; Fig. 1). Nakaishi 2004 further discloses that the elastic member is a spring having a suitable spring constant for absorbing the thermal expansion and contraction, and the spring can be properly selected in accordance with the size of the cell frame, the number of cell frames stacked, and the number of rod-like members used for the clamping mechanism ([0021]; coil springs 13, [0062], Fig. 1).
Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to modify the fastening parts (i.e. end plates) of Bhattarai to include a plurality of springs, as taught by Nakaishi 2004, in order to absorb and manage the thermal expansion and contraction of the cell stack, thereby preventing structural damage. Bhattarai further discloses:
two flow-tube plates (flow frame 40 which includes a rectangular cavity, Fig. 3; a second flow frame 40 is included on the opposite side of the ion exchange membrane, specification, pg. 3 lines 5-16), wherein said flow-tube plates are located between said two fastening parts (a first and second flow frame 40 are arranged in between the end plates 22, specification, pg. 3 lines 5-16); and
each said flow-tube plate is provided with a plurality of electrolyte tubes that correspond to an electrolyte inlet and outlet (each of the flow frames 40 include an inlet 110 connected to a plurality of supply channels 112 (the electrolyte tubes) and an outlet 120 connected to a plurality of discharge channels 122 to direct the flow of electrolyte, specification, pg. 3 lines 25-36; flow frame is in Fig. 4).
Bhattarai further teaches a cathode electrolyte tank and an anode electrolyte tank (electrolyte tanks 14 hold a positive electrolyte and a negative electrolyte; specification, pg. 3 lines 25-36) wherein both the cathode and anode electrolytes flow into the flow battery stack through a cathode electrolyte inlet and anode electrolyte inlet, both of which correspond to inlet 110 of the flow frame 40. To separate the positive and negative electrolytes, the rectangular cavity 102 of the flow frame 40 is split into two sections by a divider 130 that runs between the supply side and the discharge side of the cavity, which eases handling and enhances uniform flow (specification, pg. 3 lines 47-58).
Bhattarai further teaches a plurality of electrolyte tubes (supply channels 112 and discharge channels 122 of the flow frame 40; see Fig. 4) to supply and discharge the cathode and anode electrolytes to the battery stack via commands from an electrical component (16), which may comprise control circuitry for the pumps which pump the positive and negative electrolytes through the battery stack (specification, pg. 2 lines 55-57). In operation, the cathode or anode electrolyte enters the cathode/anode electrolyte inlet (inlet 110) and flows through the supply channels 112 into the supply side of the rectangular cavity of the flow frame 40 (specification, pg. 3 lines 47-58). After the occurrence of a redox reaction (specification, pg. 1 lines 21-23), the cathode or anode electrolyte exits the rectangular cavity, flows through the discharge channels 122, and exits the flow frame through the outlet 120 to return to their respective cathode or anode electrolyte tanks (specification, pg. 3 lines 47-58).
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Flow Frame 40 in Fig. 4 from Bhattarai
The redox flow battery of Bhattarai differs from the claimed invention in that it utilizes only two ports for electrolyte entry (inlet 110) and exit (outlet 120) via the electrolyte tubes in the flow plate, whereas the claimed invention utilizes four respective, designated ports for the cathode electrolyte inlet, the cathode electrolyte outlet, the anode electrolyte inlet, and the anode electrolyte outlet.
Nakaishi 2008 discloses a cell stack for a redox flow battery comprising four separate, designated electrolyte ports on one side of a battery stack located in between two end plates (positive electrolyte supply port 46A, negative electrolyte supply port 46B, positive electrolyte discharge port 46A', and negative electrolyte discharge port 46B', [0068]; end plates 43, [0065]; see Fig. 6). Nakaishi 2008 further teaches that these separate, dedicated ports handle the positive and negative electrolytes independently during supply and discharge, which provides the known benefits of ease of maintenance and improved workability during assembly ([0068]).
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Fig. 6 of Nakaishi 2008
Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to modify the redox flow battery of Bhattarai by incorporating a four-port configuration (four separate positive/negative inlets and outlets corresponding to respective positive/negative electrolyte tubes) located on the peripheral sides of the flow plate of Bhattarai, as suggested by Nakaishi 2008, in order to achieve the predictable advantages taught by Nakaishi 2008, namely, improving ease of maintenance and enhancing workability during the assembly process by allowing independent handling of the separate fluid paths. This modification represents a combination of prior art elements according to known methods to yield predictable results, as well as the simple substitution of one known electrolyte port configuration for another to achieve predictable results with reasonable expectation of success, as both Bhattarai and Nakaishi 2008 operate within the identical field of redox flow batteries, utilize standard manifold/fluidic routing principles; further, the substitution of fluid ports does not alter the fundamental electrochemical operation of the underlying battery system.
In addition, a person of ordinary skill in the art would have further been motivated to make this modification because Nakaishi 2008 further teaches that utilizing separate, dedicated supply and discharge ports allows the ports to be able to be strategically arranged on an opposite surface of the cell stack from the electrical terminals. This configuration ensures that in the event of an electrolyte leak from the supply/discharge portions, the electrical terminals remain isolated from the leakage, minimizing the risk of accidental current passing through an unintended path ([0068]). Modified Bhattarai (the redox flow battery of Bhattarai was modified by Hao above to have canal-etched carbon felt electrodes) further teaches:
a plurality of bipolar plates (first bipolar plate 34, Fig. 3; a second bipolar plate is included on the opposite side of the ion exchange membrane 42, specification, pg. 3 lines 5-16), wherein said bipolar plates are located between said two fastening parts (both the first and second bipolar plates 34 are located in between the two end plates 22; specification, pg. 3 lines 5-16);
each said bipolar plate has a frame plate and an accommodation space which is provided on said frame plate (bipolar plate 34 is accommodated in the rectangular cavity of the flow frame 40 which is the frame plate, specification, pg. 3 lines 5-16; Fig. 3);
and said carbon felt electrodes are fixed in said accommodation space through said frame plate (felt electrode 36 is sized to be accommodated in the rectangular cavity of the flow frame 40, specification, pg. 3 lines 5-16; Fig. 3); and
a separating membrane (ion exchange membrane 42), wherein said separating membrane is located between said two bipolar plates to separate said cathode electrolyte and said anode electrolyte (ion exchange membrane 42 is located in between the first bipolar plate 34 on the one side of the ion exchange membrane 42 and the second bipolar plate on the opposite side of the ion exchange membrane 42, specification, pg. 3 lines 5-16; Fig. 3);
However, modified Bhattarai does not expressly teach a plurality of separating membranes.
Soo discloses a redox flow battery cell stack architecture designed to optimize electrical connection configurations ([0008]) comprising a plurality of electrode-collector assemblies aligned in one direction, a plurality of separators provided between the plurality of electrode-collector assemblies, and a pair of end plates provided at both ends of the plurality of electrode-collector assemblies (claim 1). Furthermore, Soo discloses that this multi-separator, multi-electrode stack configuration provides an assembly capable of implementing a parallel connection structure of a stack, enabling both series and parallel connections in a stack selectively as necessary, and thereby reducing series synthesis resistance, improving efficiency, and reducing shunt current ([0008]).
Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to modify redox flow battery of Bhattarai by substituting or expanding its single ion exchange separating membrane into a plurality of separating membranes arranged in a stack, as taught by Soo. A person of ordinary skill in the art looking to scale the power output or customize the voltage/current characteristics of the redox flow battery of Bhattarai would have been motivated to utilize a plurality of separators and electrodes in a stack structure to selectively enable series and parallel connections as necessary. Bhattarai further discloses:
a plurality of collector plates (current collector 34 is on one side of the ion exchange membrane 42 and another current collector is on the opposite side of the exchange membrane 42, specification, pg. 3 lines 5-16; Fig. 3), wherein said collector plates are located between said two fastening parts (both current collectors 34 are located in between the two end plates 22, specification, pg. 3 lines 5-16; Fig. 3);
Regarding the limitation “…and said collector plates comprises an anode collector plate, a cathode collector plate,” Bhattarai discloses two collector plates located between two end plates as described above. While Bhattarai does not explicitly label these current collectors as an "anode collector" and a "cathode collector," these functional labels are inherent to the structure. A flow battery stack requires opposing negative (anode) and positive (cathode) terminals to function. Because Bhattarai explicitly discloses two current collectors positioned on opposing sides of an ion exchange membrane to collect current from opposing felt electrodes, one current collector inherently functions as the anode collector plate and the other inherently functions as the cathode collector plate during battery operation.
However, modified Bhattarai does not expressly teach an additional two connecting collector plates to provide external power which enters through said anode collector plate and said cathode collector plate, conducts said carbon-felt electrodes through said bipolar plates, and is used to process electrochemical redox with said cathode electrolyte and said anode electrolyte.
Baddeloo discloses flow battery comprising a cell stack with a plurality of cells, wherein at the end of the cell stack, an additional current collector plate (current connector 300 is a conductive metal plate located next to an end plate in a cell stack, [0023]-[0024]) that comprises a plurality of individual metal plates ([0011]). Baddeloo further teaches that each individual metal plate is connected to a terminal stack dielectric cable by an individual wire, and the advantage of using multiple metal plates and multiple wires is that it allows control of the current and voltage to each tab (deformable tab 310 on the current connector 300, [0023]; Fig. 3), ensuring that equal current and voltage distribution is achieved in the stack’s end cells ([0012]).
Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to modify redox flow battery of Bhattarai to comprise two collector plates such that a collector plate is located next to the each of the two end plates, as taught by Baddeloo, in order to achieve the known benefits of more evenly distributed current and voltage within the cell stack.
Regarding claim 2, modified Bhattarai teaches all features of claim 1 as described above. In the rejection of claim 1, the redox flow battery of Bhattarai was modified by incorporating a four-port configuration (four separate positive/negative inlets and outlets corresponding to respective positive/negative electrolyte tubes) located on the peripheral sides of the flow plate of Bhattarai, as suggested by Nakaishi 2008.
Nakaishi 2008 discloses that the four separate, designated electrolyte ports are located on one side (i.e. the same side) of a battery stack (positive electrolyte supply port 46A, negative electrolyte supply port 46B, positive electrolyte discharge port 46A', and negative electrolyte discharge port 46B' are located on the same side of the cell stack, [0068]; see Fig. 6). Nakaishi 2008 teaches that grouping these dedicated ports handles the positive and negative electrolytes independently during supply and discharge, providing ease of maintenance and improved workability during assembly ([0068]).
Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to further modify the flow plate of Bhattarai by providing all four designated ports on the same peripheral side of Bhattarai's flow plate, as suggested by Nakaishi 2008, in order to achieve the known benefits of streamlined plumbing, ease of maintenance, and improved workability during assembly. Further, arranging the known four ports on the same peripheral side of the flow plate represents the mere selection of one of a predictable number of routine layout options to optimize space and port accessibility.
Regarding claim 3, modified Bhattarai teaches all feature of claim 1 as described above. Bhattarai further teaches where said cathode electrolyte and said anode electrolyte are injected from said cathode electrolyte tank and said anode electrolyte tank into the flow battery stack through an external pump (pumps which pump the positive and negative electrolytes to and from the electrolyte tanks 14, specification, pg. 2 lines 45-57).
Regarding claim 4, modified Bhattarai teaches all features of claim 1 as described above. Bhattarai further teaches where each said separating membrane is integrated with a sealing set (gasket 38 has a rectangular cavity corresponding to the felt electrode 36 and is located adjacent to the flow frame 40, specification, pg. 3 lines 10-12; the flow frame 40 has provision for the gasket 38 for sealing and has a rectangular cavity configured to accommodate the porous electrode and bipolar plate, specification, pg. 3 lines 38-40).
Regarding claim 5, modified Bhattarai teaches all features of claim 1 as described above. Bhattarai further teaches where said two fastening parts are detachably connected through a plurality of locking bolts (the battery stack 12 comprises a plurality of components which are planar layers arranged between two end plates 22, where the battery stack 12 is held together by a set of bolts 24; Fig. 2).
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ALEXIS R OSTWALT whose telephone number is (571)272-8650. The examiner can normally be reached Mon-Fri 7:30am-5pm.
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/A.R.O./Examiner, Art Unit 1789
/MARLA D MCCONNELL/Supervisory Patent Examiner, Art Unit 1789
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