Maxell, Ltd. v. Amperex Technology Limited

Opinion

Case: 23-2256 Document: 39 Page: 1 Filed: 01/23/2025

NOTE: This disposition is nonprecedential.

United States Court of Appeals for the Federal Circuit ______________________

MAXELL, LTD., Appellant

v.

AMPEREX TECHNOLOGY LIMITED, Appellee ______________________

2023-2256, 2023-2258 ______________________

Appeals from the United States Patent and Trademark Office, Patent Trial and Appeal Board in Nos. IPR2021- 01440, IPR2021-01443.

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2023-2257 ______________________ Case: 23-2256 Document: 39 Page: 2 Filed: 01/23/2025

Appeal from the United States Patent and Trademark Office, Patent Trial and Appeal Board in No. IPR2021- 01441. ______________________

Decided: January 23, 2025 ______________________

ERIK SHALLMAN, Vinson & Elkins LLP, Austin, TX, ar- gued for appellant. Also represented by CORBIN CESSNA, JEFFREY TA-HWA HAN, HILARY L. PRESTON; ERIC JOSEPH KLEIN, PAIGE HOLLAND WRIGHT, Dallas, TX.

BRADY COX, Alston & Bird LLP, Dallas, TX, argued for appellee. Also represented by KIRK T. BRADLEY, CHRISTOPHER TIMOTHY LAWN DOUGLAS, NICHOLAS CHRISTOPHER MARAIS, Charlotte, NC. ______________________

Before LOURIE, REYNA, and CHEN, Circuit Judges. LOURIE, Circuit Judge. Maxell, Ltd. appeals from three decisions of the U.S. Patent Trial and Appeal Board (“the Board”) holding claims 1–5 of U.S. Patent 8,691,446 (“the ’446 patent”), claims 1–5 of U.S. Patent 9,350,019 (“the ’019 patent”), and claims 1–11 of U.S. Patent 9,077,035 (“the ’035 patent”) un- patentable as obvious. 1 Amperex Tech. Ltd. v. Maxell, Ltd., No. IPR2021-01440 (P.T.A.B. Mar. 28, 2023) (“’1440 Deci- sion”), Appeal No. 23-2256, J.A. 1–42; Amperex Tech. Ltd.

1 Appeal No. 23-2256 (relating to the ’446 patent) and Appeal No. 23-2258 (relating to the ’019 patent) were consolidated for briefing. Appeal No. 23-2257 (relating to the ’035 patent) was briefed separately. Because the issues across the appeals largely overlap, we address all three to- gether. Case: 23-2256 Document: 39 Page: 3 Filed: 01/23/2025

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v. Maxell, Ltd., No. IPR2021-01443 (P.T.A.B. Mar. 28, 2023), Appeal No. 23-2256, J.A. 43–85; Amperex Tech. Ltd. v. Maxell, Ltd., No. IPR2021-01441 (P.T.A.B. Mar. 28, 2023) (“’1441 Decision”), Appeal No. 23-2257, J.A. 1–44. 2 For the following reasons, we affirm. BACKGROUND Maxell owns the ’446 patent, the ’019 patent, and the ’035 patent, which are each generally directed to recharge- able lithium-ion batteries. The patents seek to address problems associated with basic lithium cobalt oxide (LiCoO2) electrode materials, such as structural decay, re- liability, and gas generation, by incorporating cathode ma- terials that contain at least two lithium-containing transition metal oxides having different average particle sizes. See, e.g., ’446 patent, Abstract. For example, claim 1 of the ’446 patent recites: 1. A nonaqueous secondary battery comprising: a positive electrode having a positive electrode mix- ture layer, a negative electrode, and a nonaqueous electrolyte, wherein the positive electrode contains, as an active material, at least two lithium- containing transition metal oxides having different average particle sizes, wherein said at least two lithium-contain- ing transition metal oxides having differ- ent average particle sizes have different compositions of elements between them,

2 For simplicity, we cite the ’1440 Decision on issues pertaining to both the ’446 and ’019 patents and the ’1441 Decision on issues pertaining to the ’035 patent. Case: 23-2256 Document: 39 Page: 4 Filed: 01/23/2025

said lithium-containing transition metal oxide having the smallest average particle size is a lithium-containing transition metal oxide represented by the formula (1): LixM1yM2zM3vO2 (1) wherein M1 represents at least one transi- tion metal element selected from Co, Ni and Mn, M2 represents Mg and at least one metal element selected from the group con- sisting of Ti, Zr, Ge, Nb, Al and Sn, M3 rep- resents an element other than Li, M1 and M2, and x, y, z and v are numbers satisfying the equations respectively: 0.97≤x<1.02, 0.8≤y<1.02, 0.002≤z≤0.05, and 0≤v≤0.05, the positive electrode mixture layer has a density of at least 3.5 g/cm3, and the nonaqueous electrolyte contains a com- pound having at least two nitrile groups in the molecule. Id. col. 28 ll. 35–60. All three patents recite the limitation that the “lith- ium-containing transition metal oxide having the smallest average particle size is a lithium-containing transition metal oxide represented by the formula (1): LixM yM zM vO2.” See, e.g., id. col. 28 ll. 44–48. Relevant 1 2 3

to these appeals is the identity of M2 in that formula. Each of the ’446 and ’035 patents claims that M2 “represents Mg and at least one metal element selected from the group con- sisting of Ti, Zr, Ge, Nb, Al and Sn.” Id. col. 28 ll. 50–52; ’035 patent, col. 29 ll. 33–35. Similarly, the ’019 patent claims that M2 “represents Mg, or Mg and at least one metal element selected from the group consisting of Ti, Zr, Ge, Nb, Al and Sn.” ’019 patent, col. 28 ll. 54–56. Accord- ingly, all three patents recite that M2 can be represented by Mg and Al. Case: 23-2256 Document: 39 Page: 5 Filed: 01/23/2025

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In addition to the cathode material, the patents seek to enhance thermal stability of the battery through the use of additives in the nonaqueous electrolyte. Each of the ’446 and ’019 patents claims that the electrolyte “contains a compound having at least two nitrile groups in the mole- cule.” ’446 patent, col. 28 ll. 59–60; ’019 patent, col. 28 ll. 65–67. The ’035 patent claims that the electrolyte “con- tains a fluorine-containing organic solvent.” ’035 patent, col. 29 ll. 53–54. Amperex Technology Limited (“Amperex”) petitioned for, and the Board instituted, inter partes review (“IPR”) of all claims of the ’446, ’035, and ’019 patents. Amperex ar- gued, inter alia, that claims 1–5 of the ’446 patent and claims 1–5 of the ’019 patent are invalid because, at the time of the invention, they would have been obvious over U.S. Patent Application Publication 2006/0257745 (“Choi”) 3 in combination with U.S. Patent Application 2005/0208371 (“Kim”), and that claims 1–11 of the ’035 pa- tent are invalid because, at the time of the invention, they would have been obvious over Choi in combination with U.S. Patent Application 2004/0197667 (“Noh”). Choi, which relates to “lithium batteries having high voltage stability, thermal stability and high rate discharge characteristics,” discloses a cathode material for a lithium battery that includes large and small diameter materials. Choi, Abstract, ¶ 2. The small diameter material can have the formula LixCo1-y-zNiyMzO2-αXα, where M “is selected from the group consisting of Al, Ni, Mn, Cr, Fe, Mg, Sr, V, rare earth elements and mixtures thereof.” Choi, ¶¶ 31–32. Choi further discloses that the battery includes

3 In each of the ’446 and ’019 patent IPR, Amperex cited Chinese Patent Application Publication 1822414, the Chinese counterpart to Choi. For simplicity, we cite to the U.S. publication of Choi. Case: 23-2256 Document: 39 Page: 6 Filed: 01/23/2025

an electrolytic solution that can comprise benzonitrile and acetonitrile, i.e., mononitrile solvents. Id. ¶ 61. Kim relates to improving thermal stability of cathode materials, such as lithium-containing transition metal ox- ide, through “a protection layer formed by a complex be- tween the surface of a cathode active material and an aliphatic nitrile compound.” Kim, Abstract, ¶ 8. The ali- phatic nitrile compound can be succinonitrile, i.e., a dini- trile compound. Id. ¶ 32. Noh relates to improving the discharge and thermal stability of lithium batteries using an electrolyte of “lith- ium salts, an organic solvent with a high boiling point, and a carbonate-based additive compound having substituents selected from the group consisting of a halogen, a cyano (CN), and a nitro (NO2).” Noh, Abstract. The carbonate- based additive compound can include, for example, a fluor- inated aromatic hydrocarbon, such as fluorobenzene and fluorotoluene. Id. ¶ 49. The Board determined that Amperex had established that a person of ordinary skill in the art “would have been motivated by a desire for increased thermal stability and improved discharged characteristics” to combine Choi with each of Kim and Noh to arrive at the claimed inventions of the challenged patents. ’1440 Decision, J.A. 10; ’1441 De- cision, J.A. 11. Specifically, the Board found that Amperex had presented undisputed testimony that improving ther- mal stability is critical to battery safety, and that even Maxell agreed that each of Choi, Kim, and Noh is directed to improving the thermal stability and discharge charac- teristics of lithium batteries. ’1440 Decision, J.A. 11; ’1441 Decision, J.A. 12. The Board further noted the parties’ agreement that the references teach different ways of achieving those goals. While Choi teaches improving ther- mal stability through a composite cathode material having large and small diameter particles, each of Kim and Noh teaches improving thermal stability through electrolytic Case: 23-2256 Document: 39 Page: 7 Filed: 01/23/2025

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additives. ’1440 Decision, J.A. 11–12; ’1441 Decision, J.A. 12–13. The Board found that, given that Kim and Noh taught cathode materials similar to those of Choi, and that Choi taught electrolyte materials similar to those of Kim and Noh, a person of ordinary skill in the art would have been motivated to combine the improved electrolytes of Kim and Noh with the improved cathode materials of Choi, and done so with a reasonable expectation of success. ’1440 Decision, J.A. 12–22; ’1441 Decision, J.A. 13–24. Having found that Amperex satisfied its burden of es- tablishing a motivation to combine the references, the Board turned to its obviousness analysis. The only dispute between the parties relevant here was whether a person of ordinary skill in the art would have selected Mg and Al from Choi in the claimed amount to arrive at the claimed inventions. See ’1440 Decision, J.A. 22; ’1441 Decision, J.A. 25. The Board found that undisputed evidence, including unrebutted expert testimony, which was corroborated with various secondary references, established that a person of ordinary skill in the art would have been motivated to in- corporate Mg and Al into a cathode to impart conductivity and structural enhancements, respectively. ’1440 Deci- sion, J.A. 24–29; ’1441 Decision, J.A. 27–32. In light of that unrebutted evidence, the Board rejected Maxell’s argu- ments that Mg and Al are just one of 600 possible pairs of elements that could have been selected from Choi such that Amperex must have improperly relied on hindsight to ar- rive at that combination. ’1440 Decision, J.A. 27–28; ’1441 Decision, J.A. 30–31. The Board further found that Amperex had established by preponderant evidence that Choi teaches a molar amount of M2, i.e., 0≤z≤0.5, that encompasses the claimed range, i.e., 0.002≤z≤0.05, therefore establishing a prima fa- cie case of obviousness for that limitation. ’1440 Decision, J.A. 29–30; ’1441 Decision, J.A. 32–33. Moreover, the Board found that undisputed evidence established that the molar amount of M2 would have been understood to be a Case: 23-2256 Document: 39 Page: 8 Filed: 01/23/2025

result-effective variable that a person of ordinary skill in the art would have been motivated and capable of optimiz- ing through routine experimentation. ’1440 Decision, J.A. 30–35 (citing expert testimony and supporting second- ary references); ’1441 Decision, J.A. 33–38 (same). Finding that a preponderance of evidence established that a person of ordinary skill in the art would have arrived at a cathode material that falls within the scope of the claims, the Board held that Amperex had met its burden in showing that the claims would have been obvious over the asserted prior art. Accordingly, the Board held all claims unpatentable under 35 U.S.C. § 103. Maxell timely appealed. We have jurisdiction under 28 U.S.C. § 1295(a)(4)(A). DISCUSSION Maxell raises two arguments on appeal. First, it ar- gues that the Board’s motivation-to-combine analyses were not supported by substantial evidence because, inter alia, a generic goal to improve thermal stability of a battery is not enough to induce one of ordinary skill to combine Choi with each of Kim and Noh when the references undisput- edly teach different ways of achieving that goal. Second, it argues that, even if there had been a motivation to combine the references, the Board’s obviousness analyses were not supported by substantial evidence because selecting Mg and Al in the claimed amounts from Choi to arrive at the claimed invention would have been akin to selecting the “proverbial needle in the haystack.” See Appeal No. 23-2256, Oral Arg. at 3:53–4:12, available at https:// oralarguments.cafc.uscourts.gov/default.aspx?fl=23-2256_ 01072025.mp3. We disagree and address each argument in turn. I Substantial evidence supports the Board’s findings that a person of ordinary skill in the art would have been Case: 23-2256 Document: 39 Page: 9 Filed: 01/23/2025

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motivated to combine Choi with each of Kim and Noh to arrive at a lithium battery having improved thermal sta- bility and discharge characteristics. In reaching that de- termination, the Board relied on the express teachings of the references and the undisputed testimony of Amperex’s expert witness, as well as the corroboration of that testi- mony by various supporting references. See, e.g., ’1440 De- cision, J.A. 10–22. Maxell’s primary argument on this issue is that “a gen- eral expectation of further improvement is not a sufficient basis for a motivation to combine.” Reply Br. 5. 4 Specifi- cally, it is Maxell’s position that a person of ordinary skill in the art would not have been motivated to combine Choi with Kim and Noh “because Choi already sufficiently ad- dresses the problems that Kim [and Noh] seek[] to solve: thermal stability and discharge characteristics.” Maxell Br. 34. This argument is unpersuasive. While we gener- ally agree that, without more, the mere motivation to “build something better” may not always be enough to com- bine various references, that is not the case here. See id. at 37 (citing ActiveVideo Networks, Inc. v. Verizon Commc’ns, Inc., 694 F.3d 1312, 1328 (Fed. Cir. 2012)). In contrast with ActiveVideo, where there was no rela- tion of the alleged motivation “to any specific combination of prior art elements,” 694 F.3d at 1328, the Board thor- oughly explained, relying on expert testimony, how Am- perex had established that a person of ordinary skill in the art would have combined the specific cathode material of Choi, which was designed to improve thermal stability of the battery, with the specific electrolyte of Kim and Noh, which too were designed to improve thermal stability. See ’1440 Decision, J.A. 11–20. The Board therefore did not

4 Unless otherwise indicated, references to the brief- ing are to those filed in connection with Appeal No. 23-2256. Case: 23-2256 Document: 39 Page: 10 Filed: 01/23/2025

rely on the mere fact that the references were each gener- ally directed to improving thermal stability. Moreover, Maxell’s argument that the fact that the ref- erences use different means to solve the same problem would have disincentivized combination misses the mark. Under the circumstances of this case, it is the very fact that the references teach different means that would have led a person of ordinary skill in the art to combine them. As Am- perex’s expert explained: A person of ordinary skill [would] seek out a cath- ode that would provide as much [thermal stability] as possible . . . . But a person of ordinary skill would also have understood that the electrolyte is an important part of the battery, and that inclusion of a proper electrolyte to impart properties of the battery that would enhance . . . thermal resistance to temperature excursions would [be desired]. So [the person of ordinary skill in the art] would have sought out Choi and Kim [and Noh] as a combina- tion to achieve the desired battery with the desired characteristics. ’1440 Decision, J.A. 19. In other words, the fact that the references teach discrete means to achieve the same goal in batteries that are otherwise very similar is entirely con- sistent with a motivation to combine because each of the cathode material of Choi and electrolyte of Kim or Noh, in- dependently, would have been expected to increase ther- mal stability. Accordingly, we conclude that the Board’s motivation- to-combine findings were supported by substantial evi- dence. II Maxell next argues that, even if a person of ordinary skill in the art would have combined Choi with each of Kim Case: 23-2256 Document: 39 Page: 11 Filed: 01/23/2025

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and Noh, the Board did not support its obviousness deter- mination with substantial evidence. Again, we disagree. Maxell’s argument is essentially that Choi discloses numerous options for the M2 component of its cathode ma- terial such that arriving at the selection of Mg and Al, which falls within the scope of the challenged claims, would be akin to finding a needle in a haystack. This argument, however, ignores the fact that Maxell does not specifically claim that needle, i.e., a cathode material wherein M2 is Mg and Al. Rather, the challenged claims recite a haystack of their own, in which Mg and Al are just one possible combi- nation. See, e.g., ’446 patent, col. 28 ll. 50–52. Maxell’s arguments therefore lack persuasion insofar as this case does not involve the patentability of a claim to a species where the prior art discloses only a genus encompassing that species. Cf. In re Baird, 16 F.3d 380, 382 (Fed. Cir. 1994) (“The fact that a claimed compound may be encom- passed by a disclosed generic formula does not by itself ren- der that compound obvious.”). We conclude that substantial evidence otherwise sup- ports the Board’s obviousness determination. The Board relied on ample evidence to explain why a person of ordi- nary skill in the art would have been specifically motivated to select Mg and Al from Choi. In particular, the Board relied not only on expert testimony, but explained how that testimony itself was supported by the disclosures of addi- tional literary references, such as Tukamoto 5 (teaching that Mg doping of a lithium cobalt oxide cathode can sig- nificantly increase conductivity), Madhavi 6 (teaching that

5 H. Tukamoto & A.R. West, Electronic Conductivity of LiCoO2 and Its Enhancement by Magnesium Doping, 144 J. ELECTROCHEM. SOC’Y 3164 (1997), J.A. 2913–18. 6 S. Madhavi et al., Cathodic properties of (Al, Mg) co-doped LiNi0.7Co0.3O2, 152 SOLID STATE IONICS 199 (2002), J.A. 2926–32. Case: 23-2256 Document: 39 Page: 12 Filed: 01/23/2025

Mg and Al doping of a lithium cobalt oxide cathode im- proves thermal stability), and Sato 7 (claiming a lithium co- balt oxide cathode material comprising at least one of Mg and Al). Those disclosures, pre-dating the priority date of the challenged claims and teaching the specific selection of Al and Mg—a selection that Maxell does not dispute falls within the scope of the challenged claims—constitutes sub- stantial evidence supporting the Board’s determination that it would have been obvious to arrive at the claimed cathode materials. Maxell further challenges the Board’s treatment of the claimed amount of the M2 component, arguing that Choi’s range, i.e., 0≤z≤0.5, is so broad, encompassing a very large number of distinct compositions, such that it cannot render obvious the claimed range of 0.002≤z≤0.05. We disagree. Choi’s range entirely encompasses the claimed range. “[A] prior art reference that discloses a range encompassing a somewhat narrower claimed range is sufficient to establish a prima facie case of obviousness.” In re Peterson, 315 F.3d 1325, 1330 (Fed. Cir. 2003). And here, Maxell provides no argument as to why the claimed range is critical or other- wise meaningfully different from that of Choi. Cf. Genen- tech, Inc. v. Hospira, Inc., 946 F.3d 1333, 1341 (Fed. Cir. 2020) (noting that one way to rebut obviousness of an over- lapping range is to show “that there is something special or critical about the claimed range.” (citation omitted)). In- stead, Maxell argues that, for the claimed range to overlap with the prior art, a person of ordinary skill in the art would first have to particularly select Al and Mg from the materials disclosed in Choi, and only then select a molar concentration within the claimed range, falling on the lower end of Choi’s range. But because we have already concluded that substantial evidence supports a motivation to particularly select Mg and Al from Choi, we are unmoved

7 U.S. Patent Application Publication 2005/0266315. Case: 23-2256 Document: 39 Page: 13 Filed: 01/23/2025

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by Maxell’s argument on this issue. And, in any event, the Board found, based on testimony and documentary sources, that the lower end of Choi’s range had particularly desirable features. ’1440 Decision, J.A. 30–34. CONCLUSIONS We have considered Maxell’s remaining arguments and find them unpersuasive. For the foregoing reasons, the Board’s decisions holding claims 1–5 of the ’446 patent, claims 1–5 of the ’019 patent, and claims 1–11 of the ’035 patent invalid as obvious are affirmed. AFFIRMED