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 § 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.
Claim(s) 1-5, 7, 12, and 16-19 is/are rejected under 35 U.S.C. 103 as being unpatentable over Okuda (WO 2017/073744 A1) in view of Yamada (JP 2018041555 A).
Claim 1. Okuda discloses a method for laser welding a stack of metal foils to a metal substrate (laser welding a stack of laminated tabs, abstract), comprising the steps of:
securing the stack of metal foils between a surface of the metal substrate (current collector 19) and a
interconnecting the metal foils with an initial laser-weld joint (weld W is formed on metal-foil edges, Fig. 8 and Fig. 9A), the interconnecting step including serially tracing a plurality of lateral paths along the metal-foil edges with a laser beam (laser beam moves in a plurality of lateral paths from P1 to P2 along the X-axis and shifted in the Z-axis, page 34-35, Fig. 8); and
connecting the stack of interconnected metal foils to the metal substrate by tracing (metal foils are connected by the weld W, Fig. 9A), with a laser beam, a path along the interface between the initial laser-weld joint and the metal-substrate surface (in the process of irradiating the energy beam linearly from position P1 to P2 and shifting the beam in the z-axis direction the boundary line Wa of the weld W extends from the weld W to the current collector 19).
Okuda does not explicitly disclose a subsequent weld along the interface between the weld and substrate surface.
Okuda discloses that the laser irradiates the metal foil edges linearly and shifts in the z-axis direction (page 34-35, Fig. 8). There would be two obvious methods of shifting the laser beam in the z-axis, one where the beam starts at the top of the stack and each subsequent beam shifts down the z-axis or the beam starts at the bottom of the stack and shifts up the z-axis. Therefore, it would have been obvious for one of ordinary skill in the art to try irradiating the laser beam and shifting it down the Z-axis, from the top to bottom.
If one of ordinary skill in the art started the beam at the top of the stack then the linear welds at the bottom of the stack would have formed a weld along the interface of the laser weld on the metal-foil edge and the current collector, reading on the limitation.
Okuda does not disclose a removable clamp.
Yamada discloses a welding jig for laser welding a tab stack of an electrode assembly (Fig. 3) wherein a suction shaft 115 (Fig. 4) presses on the tab stack (par. 44, Fig. 4) and can be lifted up vertically (par. 40).
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 Okuda to incorporate the teachings of Yamada and provide a suction shaft that presses on the tab stack. Doing so would have the benefit of prevent displacement of the tabs during welding (par. 13, Yamada).
Claim 2. Okuda in view of Yamada discloses the method of claim 1, wherein each of the lateral paths, when being traced, is closer to the metal-substrate surface than any preceding one of the lateral paths (see claim 1 mapping for each linear weld to move down the z-axis, getting closer to the substrate).
Claim 3. Okuda in view of Yamada discloses the method of claim 1, further comprising displacing the removable clamp from the stack of metal foils after the connecting step (suction shaft 115 goes into a released state after welding wherein the air cylinder 110 retracts, par. 43-44, Yamada).
Claim 4. Okuda in view of Yamada discloses the method of claim 1, wherein:
the securing step includes clamping the metal substrate and the stack of metal foils between the removable clamp and a backing plate (a holding state where the suction shaft presses the tab stacks, par. 44, Yamada); and
the method further comprises, after the connecting step, displacing the removable clamp from the backing plate to facilitate extraction of the metal substrate and the stack of metal foils as welded together by the interconnecting and connecting steps (suction shaft 115 goes into a released state after welding wherein the air cylinder 110 retracts, par. 43-44, Yamada).
Claim 5. Okuda in view of Yamada discloses the method of claim 1, wherein each tracing of a lateral path in the interconnecting step produces a weld line (laser beam moves in a plurality of lateral paths from P1 to P2 along the X-axis and shifted in the Z-axis, page 34-35, Fig. 8), and
Okuda in view of Yamada does not explicitly disclose wherein weld lines produced by pairs of adjacent lateral paths overlap spatially.
Okuda shows that the result of the plurality of lateral weld lines produces an uninterrupted solid weld (Fig. 9A). It would have been obvious to one of ordinary skill in the art that the plurality of lateral weld lines would overlap in order to produce an uninterrupted single solid weld.
Claim 7. Okuda in view of Yamada discloses the method of claim 1, wherein the laser beam in the connecting step scans a repeating two-dimensional scan pattern along the interface (the multiple linear welds at the bottom of the foil stack moves a lateral path and then shifts in the z-axis results in a repeating 2D pattern, page 34-35, Fig. 8).
Claim 12. Okuda in view of Yamada discloses the method of claim 1, wherein:
the securing step includes offsetting the metal-foil edges from each other such that the side of the stack is slanted in the direction toward the removable clamp (edge face 25c can be slanted, Fig. 8); and
the laser beam in each of the interconnecting and connecting steps is incident along a direction that is at an oblique angle with respect to the metal-substrate surface (angle of the laser beam is between 10-80 deg with respect to the X-Y plane, Fig. 6A).
Claim 16. Okuda in view of Yamada discloses the method of claim 1, wherein thickness of each of the metal foils is between 5 and 30 micrometers (thickness of the foil is between 5-30 um, page 30).
Claim 17. Okuda in view of Yamada discloses the method of claim 16, wherein the stack includes at least ten metal foils (tab laminate may be 0.6mm to 1 mm, with a tab thickness of 10 um, this stack would have at least 60 foils, page 30, par. 2).
Claim 18. Okuda in view of Yamada discloses the method of claim 16, wherein the metal foils are made of aluminum (aluminum foil, page 16, par. 3).
Claim 19. Okuda in view of Yamada discloses the method of claim 18, wherein the metal substrate is made of aluminum or an aluminum alloy (current collector can be formed of the same material as the foil, page 15, par. 2).
Claim(s) 6 is/are rejected under 35 U.S.C. 103 as being unpatentable over Okuda in view of Yamada as applied to claim 1 above, and further in view of Uchida (US 2018/0361504 A1).
Claim 6. Okuda in view of Yamada does not disclose the method of claim 1, wherein the connecting step includes melting a portion of the initial laser-weld joint closest to the metal-substrate surface without melting a portion of the initial laser-weld joint farthest from the metal-substrate surface.
Uchida discloses a laser welding stacked metal foils wherein the scanning laser beam has a diameter of 0.4 mm (par. 54).
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 Okuda in view of Yamada to incorporate the teachings of Uchida and have a laser beam with a diameter of 0.4 mm. Uchida shows that one of ordinary skill in the art would be capable of selecting a laser diameter within the range of 0.1 – 0.5 mm based on design constraints and specifications.
The combination of the prior art would result in the limitation because with a beam diameter of 0.4 mm and a stack thickness of 2.4 mm (page 31, par. 2), the latter weld lines at the bottom of the stack and substrate interface would not melt the welded portion at the top of the weld.
Claim(s) 8 is/are rejected under 35 U.S.C. 103 as being unpatentable over Okuda in view of Yamada as applied to claim 7 above, and further in view of Yang (US 2019/0061056 A1).
Claim 8. Okuda in view of Yamada does not disclose the method of claim 7, wherein the path traced by the laser beam in the connecting step oscillates across the interface in a circular or oval fashion.
Okuda discloses multiple oscillating welds on different edge faces (Fig. 7 and Fig. 11).
Yang discloses laser welding overlapping metal workpieces wherein the weld has multiple successive weld paths (78, Fig. 10) wherein each path the laser beam has an oscillating pattern (Fig. 12, par. 47).
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 Okuda in view of Yamada to incorporate the teachings of Yang and give each of the plurality of lateral welds an oscillating pattern. Doing so would have the benefit of enhancing the strength of the weld through the high travel speed and stirring of the keyhole (par. 14, Yang).
Claim(s) 13 is/are rejected under 35 U.S.C. 103 as being unpatentable over Okuda in view of Yamada as applied to claim 12 above, and further in view of Russ (US 2018/0175336 A1).
Claim 13. Okuda in view of Yamada discloses the method of claim 12, wherein thickness of each of the metal foils is between 5 and 30 micrometers (thickness of the foil is between 5-30 um, page 30), and
Okuda in view of Yamada does not disclose wherein the securing step produces an average offset, between the edges of each pair of adjacent metal foils, in the range between 20 and 200 micrometers, as averaged over the stack.
Russ discloses welding a stack of metal foil wherein the foil stack is inclined at an angle of between 0.5 deg to 20 deg (par. 14, Fig. 3).
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 Okuda in view of Yamada to incorporate the teachings of Russ and provide that the angle of inclination of the foil stack is between 0.5 deg to 20 deg. Russ demonstrates that one of ordinary skill in the art would be capable of producing an angled stack face based on design specification and constraints.
The combination of the prior art would result in at least an average offset between the edges of each pair of adjacent metal foil of 56 um based on a foil thickness of 10 um (thickness of the foil can be between 5-30 um, page 30, Okuda).
Claim(s) 14-15 is/are rejected under 35 U.S.C. 103 as being unpatentable over Okuda in view of Yamada and Russ as applied to claim 13 above, and further in view of Uchida (US 2018/0361504 A1).
Claim 14. Okuda in view of Yamada and Russ discloses the method of claim 13, wherein, in the interconnecting step, each of the lateral paths has a length of at least 5 millimeters (thickness of the welded stack may be up to 2.4 mm, page 31, par. 2, and the maximum area of the welded portion can be between 4 mm2– 40 mm2, page 28, which means the length of the weld can be at least 5 mm to form an area of 12 mm2) and
Uchida discloses a laser welding stacked metal foils wherein the scanning laser beam has a diameter of 0.4 mm (par. 54).
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 Okuda in view of Yamada to incorporate the teachings of Uchida and have a laser beam with a diameter of 0.4 mm. Uchida shows that one of ordinary skill in the art would be capable of selecting a laser diameter within the range of 0.1 – 0.5 mm based on design constraints and specifications.
Claim 15. Okuda in view of Yamada discloses the method of claim 13, wherein the connecting step includes forming a melt pool along the interface, width of the melt pool in dimension transverse to the interface being in the range between 0.1 and 2 millimeters
Uchida discloses a laser welding stacked metal foils wherein the scanning laser beam has a diameter of 0.4 mm (par. 54).
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 Okuda in view of Yamada to incorporate the teachings of Uchida and have a laser beam with a diameter of 0.4 mm. Uchida shows that one of ordinary skill in the art would be capable of selecting a laser diameter within the range of 0.1 – 0.5 mm based on design constraints and specifications.
This combination results in reading on the limitation because if the diameter of the laser beam that is melting the metal foil has a diameter of 0.4 mm then the width of the melt pool transverse to the interface would have a width between 0.1 and 2 mm.
Claim(s) 1 and 9 is/are rejected under 35 U.S.C. 103 as being unpatentable over Okuda (WO 2017/073744 A1) in view of Yamada (JP 2018/041555 A) and Tateyama (US 2018/0361506 A1).
Claim 1. Okuda discloses a method for laser welding a stack of metal foils to a metal substrate (laser welding a stack of laminated tabs, abstract), comprising the steps of:
securing the stack of metal foils between a surface of the metal substrate (current collector 19) and a
interconnecting the metal foils with an initial laser-weld joint (weld W is formed on metal-foil edges, Fig. 8 and Fig. 9A), the interconnecting step including serially tracing a plurality of lateral paths along the metal-foil edges with a laser beam (laser beam moves in a plurality of lateral paths from P1 to P2 along the X-axis and shifted in the Z-axis, page 34-35, Fig. 8); and
Okuda does not disclose a removable clamp.
Yamada discloses a welding jig for laser welding a tab stack of an electrode assembly (Fig. 3) wherein a suction shaft 115 (Fig. 4) presses on the tab stack (par. 44, Fig. 4) and can be lifted up vertically (par. 40).
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 Okuda to incorporate the teachings of Yamada and provide a a suction shaft that presses on the tab stack. Doing so would have the benefit of prevent displacement of the tabs during welding (par. 13, Yamada).
Okuda in view of Yamada does not disclose connecting the stack of interconnected metal foils to the metal substrate by tracing, with a laser beam, a path along the interface between the initial laser-weld joint and the metal-substrate surface.
Tateyama discloses a two step laser spot welding method wherein the first laser performs conduction welding over the face of the stacked metal foil (Fig. 6, claim 5) and then a second laser performs keyhole welding across the initial weld (Fig. 6, claim 5).
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 Okuda in view of Yamada to incorporate the teachings of Tateyama and provide a connecting step wherein a second laser performs keyhole welding across the initial weld. Doing so would have the benefit of reducing blowholes in the welds (par. 4, Tateyama).
Claim 9. Okuda in view of Yamada and Tateyama discloses the method of claim 1, wherein:
the laser beam in the interconnecting step forms the initial laser-weld joint by conduction welding (claim 5, Tateyama); and
the connecting step includes keyhole welding the stack of interconnected metal foils to the metal substrate (claim 5, Tateyama).
Claim(s) 10-11 is/are rejected under 35 U.S.C. 103 as being unpatentable over Okuda in view of Yamada and Tateyama as applied to claim 9 above, and further in view of Kangastupa (US 2020/0306878 A1).
Claim 10. Okuda in view of Yamada and Tateyama does not disclose the method of claim 9, wherein the laser beam in the interconnecting step is an annular laser beam.
Kangastupa discloses an apparatus for laser welding wherein a center and ring laser beam profiles are used to perform keyhole welding and heat conduction welding (par. 59, Fig. 1C) where the apparatus can give independent control of the power to the ring and center beams (par. 59).
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 Okuda in view of Yamada and Tateyama to incorporate the teachings of Kangastupa and provide annular and center beam for the purpose of hybrid keyhole and conduction welding. Doing so would have the benefit of reducing spatter (par. 36, Kangastupa).
Claim 11. Okuda in view of Yamada, Tateyama, and Kangastupa discloses the method of claim 9, wherein the laser beam in the connecting step includes a central laser beam and an annular laser beam (par. 59, Kangastupa).
Conclusion
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/SIMPSON A CHEN/ Examiner, Art Unit 3761
/ELIZABETH M KERR/ Primary Examiner, Art Unit 3761
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