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 .
DETAILED ACTION
Election/Restriction
Restriction to one of the following inventions is required under 35 U.S.C. 121:
I. Claims 1-15, drawn to A method of welding a metal foil, classified in B23K 26/21.
II. Claims 16-21, drawn to A component for a battery, classified in H01M 50/536.
The inventions are independent or distinct, each from the other because:
Inventions I and II are related as process of making and product made. The inventions are distinct if either or both of the following can be shown: (1) that the process as claimed can be used to make another and materially different product or (2) that the product as claimed can be made by another and materially different process (MPEP § 806.05(f)). In the instant case the product as claimed can be made by another and materially different process. For example, the battery of Group II, in which a metal foil stack is welded to a metal substrate by a plurality of weld nuggets, could be made by a laser welding process that uses a single beam rather than a composite beam having a center beam and a surrounding annular beam; by a composite-beam process in which the center beam is on for 15 microseconds or for 600 microseconds rather than for between 20 and 500 microseconds; by a composite-beam process in which the peak power of the center beam is 0.45 kilowatt rather than at least 0.5 kilowatt; or by an altogether different joining process such as ultrasonic welding, resistance welding, or soldering. Restriction for examination purposes as indicated is proper because all the inventions listed in this action are independent or distinct for the reasons given above and there would be a serious search and/or examination burden if restriction were not required because one or more of the following reasons apply:
The inventions have acquired a separate status in the art in view of their separate classification, as set forth above. Group I is classified in B23K 26/21, whereas Group II is classified in H01M 50/536. A search of the classification in which one group is classified would not encompass the classification in which the other group is classified, and a proper search of each group therefore requires a separate field of search. Accordingly, there would be a serious search burden if restriction were not required (MPEP § 808.02).
Applicant is advised that the reply to this requirement to be complete must include (i) an election of an invention to be examined even though the requirement may be traversed (37 CFR 1.143) and (ii) identification of the claims encompassing the elected invention.
The election of an invention may be made with or without traverse. To reserve a right to petition, the election must be made with traverse. If the reply does not distinctly and specifically point out supposed errors in the restriction requirement, the election shall be treated as an election without traverse. Traversal must be presented at the time of election in order to be considered timely. Failure to timely traverse the requirement will result in the loss of right to petition under 37 CFR 1.144. If claims are added after the election, applicant must indicate which of these claims are readable upon the elected invention.
Should applicant traverse on the ground that the inventions are not patentably distinct, applicant should submit evidence or identify such evidence now of record showing the inventions to be obvious variants or clearly admit on the record that this is the case. In either instance, if the examiner finds one of the inventions unpatentable over the prior art, the evidence or admission may be used in a rejection under 35 U.S.C. 103 or pre-AIA 35 U.S.C. 103(a) of the other invention.
During a telephone conversation with Gunn, J. on 06/25/2026, a provisional election was made without traverse to prosecute the invention of the methods of laser welding a metal foil stack, claims 1-15. Affirmation of this election must be made by applicant in replying to this Office action. Claims 16-21 withdrawn from further consideration by the examiner, 37 CFR 1.142(b), as being drawn to a non-elected invention.
Applicant is reminded that upon the cancelation of claims to a non-elected invention, the inventorship must be corrected in compliance with 37 CFR 1.48(a) if one or more of the currently named inventors is no longer an inventor of at least one claim remaining in the application. A request to correct inventorship under 37 CFR 1.48(a) must be accompanied by an application data sheet in accordance with 37 CFR 1.76 that identifies each inventor by his or her legal name and by the processing fee required under 37 CFR 1.17(i).
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claim(s) 1-8 and 11-15 are rejected under 35 U.S.C. 103 as being unpatentable over Närhi et al. (US 2021/0299785 A1; hereinafter “Narhi”) in view of Nagel et al. (WO 2022/179760 A1; hereinafter “Nagel”).
Claim 1: Närhi is directed to the field of laser welding a stack of thin metal foils to a much thicker metal tab in the manufacture of lithium-ion battery cells, in which each foil stack must be electrically connected to a metal tab that protrudes from the cell ([0001], [0004]). Närhi states that the mechanical attachment and electrical connection of each foil to the respective tab is critical for the integrity, reliability, and performance of the battery, that joining multiple thin metal foils to a much thicker metal tab is challenging, and that the completed joint must be strong, durable, and have low electrical resistance through the full thickness of the foil stack and the tab ([0005], [0007]). Närhi discloses a method for laser welding a metal foil stack to a metal substrate — a stack of metal foils 22 is welded to a metal tab 24 ([0020]) — comprising the following limitations;
Clamping a stack of metal foils against a support surface of a metal substrate. Närhi assembles the foils into a stack and compresses “the stack of foils and the tab” with a clamp 26 to form the workpiece ([0020]), the surface of tab 24 serving as the support surface.
Irradiating the stack with a beam of laser pulses to weld the stack to the substrate. Närhi forms each weld “by delivering a pulse of laser radiation through each core” onto the workpiece ([0038]).
The beam being a composite beam including a center beam and an annular beam surrounding the center beam. Närhi’s focused beam 18 includes “a center beam and a concentric annular beam” ([0008]; FIG. 1B; center core 40 and annular core 44).
A peak power of the center beam being at least 0.5 kilowatt for each of the laser pulses. Närhi’s center-beam power P2 is in the range of 1300–1600 W (copper) and 1450–1750 W (aluminum) ([0030], [0036]) — e.g., 1450 W and 1600 W in the worked examples ([0026], [0032]) — each exceeding 0.5 kW.
The center beam being on for a duration of between 20 and 500 microseconds for each of the laser pulses. Närhi’s center-beam duration T2 is “between about 0.1 milliseconds and about 5 milliseconds” ([0030], [0036]); the lower end (0.1 ms = 100 µs) falls within the claimed range. Where a claimed range overlaps a range disclosed in the prior art, a prima facie case of obviousness exists (MPEP 2142).
Focusing the composite beam such that a largest transverse 1/e² extent of the center beam is less than 150 micrometers at the stack. Närhi’s focused center beam has “a diameter of about 140 µm” at the workpiece ([0025]), which is less than 150 µm.
Scanning — limitation (a), top surface. Närhi scans the composite beam such that an initial series of pulses are incident at a series of mutually distinct locations on the top surface of the top-most foil facing away from the support surface: beam scanner 30 “translates focused beam 18 laterally between the plurality of locations-to-be-welded” ([0038]), the welds being formed “at 42 locations along two staggered rows” on the front (outside) surface of the stack ([0026], [0037]; FIGS. 3A–3B).
Närhi does not expressly disclose limitation (b) — that a series of the laser pulses are incident at a series of mutually distinct locations on a side of the stack, the side being between the support surface and the top surface. Närhi welds only the top (front) surface of the stack.
Nagel is analogous art. Nagel is in the same field of endeavor as Närhi and as the claimed invention, namely laser welding a stack of metal foils to a metal substrate as applied to the production of lithium-ion battery cells (pg. 1, lines 11–14), and is directed to the same problem confronted by Närhi, namely that joining multiple thin metal foils to a much thicker metal tab is challenging and that the completed joint must be strong, durable, and have low electrical resistance (pg. 2, lines 17–21). Nagel teaches irradiating the side of the stack: “serially tracing a plurality of lateral paths along the metal-foil edges” (claim 1), the edges 120E forming “a side of the stack” on the substrate surface (pg. 5, lines 28–32), with the beam “incident along a direction that is at an oblique angle with respect to the metal-substrate surface” (pg. 8, lines 15–19). Nagel further teaches that welding the side of the stack in this manner “increases the area accessible for laser welding… allowing for the formation of a stronger laser-weld joint” (pg. 8, lines 18–21). Närhi likewise teaches that “a larger number and higher density of welds will provide a stronger joint with higher electrical conductivity” ([0037]). Both Närhi and Nagel weld battery foil stacks to metal substrates using the same composite laser beam, having a center beam and a surrounding annular beam, generated by the same commercially available fiber laser (Närhi [0019]–[0020]; Nagel pg. 12, lines 9–15).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of Närhi by scanning the composite beam such that, after the initial series of laser pulses has been delivered to mutually distinct locations on the top surface of the top-most foil, a subsequent series of the laser pulses is delivered to mutually distinct locations on the side of the stack, in the manner taught by Nagel. One of ordinary skill in the art would have been motivated to make this modification in order to increase the area over which the foil stack is welded to the metal substrate and thereby to form a stronger joint having higher electrical conductivity because both references weld battery foil stacks to metal substrates using the same composite center-and-annular laser beam, so that the side irradiation could be carried out with the same laser and scanner already taught by Närhi.
Claim 2: Närhi discloses that at least some of the laser pulses form a weld nugget that penetrates into the metal substrate — the center beam “forms a keyhole… that penetrates through all the foils and the tab” ([0023]), i.e., into the substrate.
Claim 3: Nagel teaches arranging the metal foils such that the side of the stack is orthogonal to the support surface to within 10 degrees — in the no-slant configuration the side is “essentially perpendicular to” the substrate surface, “slant angle 320A being 90 degrees, or between 80 and 90 degrees” (pg. 13, lines 25–28) — and directing the composite beam onto the stack at an oblique angle with respect to the support surface (pg. 8, lines 15–19). It would have been obvious to combine these teachings for the reasons given for claim 1; further, directing a single scanned beam onto both the top surface and the orthogonal side of the stack (claim 1) necessarily requires oblique incidence relative to the support surface.
Claim 4: The combination renders obvious the oblique angle being between 30 and 60 degrees. Nagel teaches that the side may be slanted at a “slant angle 320A… in the range between 10 and 80 degrees” with the beam incident near-normal to that side (pg. 9, lines 10–13), such that the angle of incidence relative to the support surface overlaps the claimed range.
Claim 5: Närhi discloses that the support surface extends beyond the side of the stack. As shown in FIG. 1A, metal tab 24, against which the stack of metal foils 22 is clamped by clamp 26, extends laterally beyond the side of foil stack 22, such that the support surface of tab 24 extends beyond the side of the stack ([0020]).
Claims 6 and 7: Närhi forms the welds at discrete, mutually spaced locations (“42 locations along two staggered rows,” [0026]; FIGS. 3A–3B showing separated weld nuggets) using a center beam of about 140 µm ([0025]). It would have been obvious to space the incidence locations of the center beam at a center-to-center distance of at least 100 micrometers (claim 6), which likewise exceeds the largest transverse 1/e² dimension of the center beam (claim 7), so that adjacent welds do not overlap and the foils between welds are not subjected to excessive or sustained heating — a routine design choice yielding the predictable result of discrete, non-overlapping welds.
Claim 8: The combination renders obvious sequentially tracing, with the composite beam, a plurality of paths parallel to an interface corner between the side and the support surface, each path closer than each preceding path to the interface corner. Nagel traces a plurality of lateral paths parallel to the foil edges, “each subsequent lateral path… closer to the metal-tab surface than any preceding” path (pg. 6, lines 9–13), i.e., progressively closer to the interface corner. In the combination of claim 1, the composite beam welds both the top surface (Närhi) and the side (Nagel); accordingly, at least one path is traced during the initial series on the top surface and at least one path is traced during the subsequent series on the side.
Claim 11: Nagel teaches a center beam having a 1/e² diameter “in the range between 15 and 100 µm” (pg. 12, lines 6–9), the lower portion (15–50 µm) being at most 50 micrometers as claimed. Närhi teaches a center-beam peak power of at least 1 kilowatt (P2 of 1450–1600 W; [0026], [0032]) and a center-beam duration T2 of “between about 0.1 milliseconds and about 5 milliseconds” ([0030], [0036]), the lower end (100 µs) falling within the claimed 50–200 microseconds. It would have been obvious to select a center-beam extent of at most 50 µm as taught by Nagel, together with Närhi’s power and duration, to concentrate the keyhole and form the narrow, deep-penetration welds desired for foil-to-substrate joining.
Claim 12: Närhi discloses, for each pair of laser pulses, turning on the annular beam before the center beam — in the copper method the annular beam is “ramped up to a first power P1 and… sustained… for a first time T1” to preheat the surface, and “towards the end of first time T1, the power of the center beam is ramped up” ([0022]–[0023]).
Claim 13: Närhi discloses, for each pair of laser pulses, turning off the center beam before the annular beam — in the aluminum method the center beam is “sustained for a second time T2… and then… ramped down,” while the annular beam is sustained for a longer first time T1, “the first time being longer than the second time” ([0009], [0031]).
Claim 14: Närhi discloses a stack of “between 20 and 100 individual foils” ([0036]) and teaches that the welded area “is easily scaled by changing the number of individual welds,” with a larger number providing a stronger joint ([0037]); Nagel contemplates a stack height of “1 and 3 mm” (pg. 9, lines 11-12). It would have been obvious to provide a stack of at least 100 metal foils in order to increase the storage capacity of the battery cell — a result the references teach is achievable by scaling the number of foils and welds.
Claim 15: Närhi discloses that each foil has “a thickness between about 5 µm and about 15 µm” ([0036]), which is at most 20 micrometers as claimed (Nagel likewise teaches 5–30 µm, pg. 5, lines 3-5).
Claims 9 and 10 are rejected under 35 U.S.C. 103 as being unpatentable over Närhi in view of Nagel, and further in view of Freitag et al. (US 2010/0326967 A1; hereinafter “Freitag”).
Claims 9 and 10: Närhi in view of Nagel teaches the method of claim 8, in which the composite beam sequentially traces a plurality of paths parallel to the interface corner between the side of the stack and the support surface, each path being closer to the interface corner than each preceding path, such that the last of those paths to be traced is a final path nearest the interface.
Nagel teaches that it is at that interface that the foil stack is joined to the metal substrate: the connecting step traces a path along the interface between the initial laser-weld joint and the metal-substrate surface, and it is this step that forms the robust, high-quality electrical connection between the metal foils and the metal substrate, the conductivity and robustness of which are to be maximized (pg. 7, lines 14–19; pg. 11, lines 20–24). Närhi teaches that “a larger number and higher density of welds will provide a stronger joint with higher electrical conductivity” ([0037]). Närhi further delivers the laser pulses to mutually distinct incidence locations by means of a beam scanner 30, which may include galvanometer-actuated mirrors that enable rapid movement of the focus between locations ([0021], [0038]).
Närhi and Nagel do not expressly disclose repeating the tracing of the final path using a different set of incidence locations of the center beam (claim 9), interlaced with the incidence locations used during the sequential tracing (claim 10).
Freitag is analogous art. Freitag is in the same field of endeavor as Närhi, as Nagel, and as the claimed invention, namely laser welding the metal components of electrochemical devices such as batteries and capacitors ([0002], [0004]), and Freitag is directed to the same problem, namely how to obtain the weld penetration required along a weld path without the heat of welding accumulating to the point of damaging the workpiece ([0005], [0008]).
Freitag teaches welding a path in two passes. In a first welding pass, the laser is intermittently turned on and off while traversing the path, thereby forming a first set of intermittent welds spaced from one another by unwelded sections ([0011], [0049]–[0050]; FIG. 6). In a second welding pass along that same path, the laser is again intermittently turned on and off, with the beam directed to the unwelded sections, thereby forming a second set of intermittent welds ([0011], [0051]; FIG. 7). Each weld of the second pass begins at the end point of a weld of the first pass and ends at the beginning point of the next weld of the first pass, so that the welds of the second pass occupy the gaps between the welds of the first pass and the two sets together form a continuous weld seam ([0012], [0052]; claim 1).
Freitag also teaches the reason for welding a path in this manner. The separated weld segments of the first pass have sufficient unwelded distance between them to limit the amount of heat generated at any given weld location, and the unwelded portions between those segments are welded only after sufficient time has passed to allow for heat dissipation, thereby limiting the peak temperature produced anywhere along the seam ([0033]). Traversing the path twice allows the heat generated at any given segment to cool before an adjoining segment is welded ([0034]). Freitag teaches that this two-pass approach holds the peak temperature below the point at which damage occurs while still achieving the necessary weld penetration and microstructure throughout the entire welded seam ([0008]), and that it thereby enables greater weld penetration at the interface being welded without incurring the damaging higher temperatures that a single pass would produce ([0063]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of Närhi in view of Nagel by tracing the final path a second time after the step of sequentially tracing has been completed, and by delivering the laser pulses of that second tracing to a different set of incidence locations of the center beam, positioned in the gaps between, and thus interlaced with, the incidence locations used during the first tracing of that final path, in the manner taught by Freitag.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ATEF A SHAT whose telephone number is (571)270-0364. The examiner can normally be reached 8am-5pm.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Michael Cleveland can be reached at 5712721418. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/ATEF A SHAT/Examiner, Art Unit 1712
/MICHAEL B CLEVELAND/Supervisory Patent Examiner, Art Unit 1712
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