PTAB

IPR2025-00825

Shenzhen FbTech Electronics Ltd v. LithiumHub Technologies LLC

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: LITHIUM STARTER BATTERY AND SOLID STATE SWITCH THEREFOR
  • Brief Description: The ’994 patent discloses a lithium-based starter battery pack for vehicles. The invention purports to be a novel configuration of solid-state switches, arranged in parallel pairs, designed to increase current capabilities and provide protective cutoff and cell balancing functions. Petitioner argued that the challenged claims are not entitled to their asserted priority dates, making the effective filing date November 28, 2011.

3. Grounds for Unpatentability

Ground 1: Obviousness over Pevear, Porsche, and Poff - Claims 1, 4-9, 11-16, and 18-23 are obvious over Pevear in view of Porsche and Poff.

  • Prior Art Relied Upon: Pevear (Application # 2013/0101874), Porsche (a November 2009 press release), and Poff (Application # 2007/0145944).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Pevear taught the foundational elements of independent claim 1, including a lithium-ion automotive starter battery with a housing, rechargeable cells, and a circuit board with a power management system providing cell balancing and a cutoff function. Pevear’s cutoff circuit used two groups of parallel MOSFETs connected in series. Petitioner contended that Pevear, however, did not teach the specific limitation of "a plurality of pairs of solid state switches with each pair of solid state switches connected in a parallel configuration to another pair." To supply this missing element, Petitioner asserted that Poff disclosed an enhanced battery protection system with a conventional transistor pair and a redundant transistor pair connected in parallel, teaching the claimed parallel pair configuration. Furthermore, for limitations related to lithium iron phosphate cells (e.g., claims 8-9 and 15-16), Porsche was cited for teaching a lithium-ion starter battery using that specific, high-performance chemistry.
    • Motivation to Combine: A POSITA would combine Pevear and Poff to improve the reliability of Pevear’s cutoff circuit by incorporating Poff’s known redundant switch design, which was a finite and predictable solution for battery protection. A POSITA would also be motivated to use the specific lithium-iron-phosphate cells from Porsche in Pevear’s battery system to achieve the known benefits of that chemistry, such as improved performance and weight reduction in an automotive context.
    • Expectation of Success: Petitioner asserted a POSITA would have a high expectation of success, as the combination involved the simple substitution of one known cutoff circuit (Poff's) for another (Pevear's) to obtain predictable improvements in reliability.

Ground 2: Obviousness over Pevear, Porsche, Poff, and Wu - Claim 2 is obvious over Pevear, Porsche, Poff, and Wu.

  • Prior Art Relied Upon: Pevear (Application # 2013/0101874), Porsche (a November 2009 press release), Poff (Application # 2007/0145944), and Wu (Application # 2007/0080662).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground built upon the combination of Pevear, Porsche, and Poff from Ground 1. Petitioner argued that this primary combination taught all elements of claim 2 except for the "means for periodically measuring a load to detect a change in load impedance." Petitioner asserted that Wu, which discloses a master control module for a battery pack, explicitly taught this missing element by disclosing circuitry for di-electrical impedance detection.
    • Motivation to Combine: A POSITA would be motivated to incorporate Wu’s impedance detection functionality into the battery management system of the primary combination to enhance the protective features of the battery, as all references deal with protecting lithium-ion batteries.
    • Expectation of Success: Success would be expected because adding a known monitoring function (impedance detection from Wu) to an existing battery management system was a well-understood design choice.

Ground 3: Obviousness over Pevear, Porsche, Poff, and Kashine - Claim 3 is obvious over Pevear, Porsche, Poff, and Kashine.

  • Prior Art Relied Upon: Pevear (Application # 2013/0101874), Porsche (a November 2009 press release), Poff (Application # 2007/0145944), and Kashine (Application # 2003/0169021).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground also relied on the primary combination from Ground 1. Petitioner argued the combination did not explicitly teach claim 3's limitation of a "current monitor being connected to a current comparator and a set-reset latch" for turning off a switch upon a short circuit. Petitioner asserted that Kashine, which relates to secondary battery protection devices, taught this specific control mechanism, disclosing that an excess current signal is input to a latch, which in turn causes a logic circuit to turn off a switching element.
    • Motivation to Combine: A POSITA would have been motivated to incorporate Kashine’s specific short-circuit protection mechanism into the primary combination’s design as one of a finite number of predictable solutions for managing current flow and protecting the battery.
  • Additional Grounds: Petitioner asserted an additional obviousness challenge (Ground 4) against claims 10 and 17 based on the combination of Pevear, Porsche, Poff, and Shibano (Application # 2004/0096745). This ground relied on Shibano to teach the specific lithium-based cell chemistries recited in those claims, arguing it was a simple substitution of one known electrode material for another.

4. Key Claim Construction Positions

  • Petitioner noted that in a related ITC proceeding, the term “1 volt” in the preamble of claim 14 was construed to mean “12 volt.”
  • Petitioner also highlighted an ongoing dispute in the ITC proceeding as to whether the claim terms "a circuit board... configured to balance each individual cell" and "a circuit board... having a cutoff function incorporated therein" are means-plus-function limitations under §112.

5. Arguments Regarding Discretionary Denial

  • Petitioner argued that discretionary denial under Fintiv would be inappropriate. It was asserted that the parallel district court cases are stayed, and the co-pending ITC investigation does not substantially overlap with the Petition.
  • Specifically, Petitioner contended that several challenged claims (2, 3, 10, and 17) were not at issue in the ITC investigation. Moreover, the invalidity grounds and prior art references in the Petition (notably Pevear, Porsche, Kashine, and Shibano) differ significantly from those in the ITC proceeding, thus weighing against denial.

6. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-23 of the ’994 patent as unpatentable under 35 U.S.C. §103.