PTAB

IPR2015-01243

Snap On Inc v. Milwaukee Electric Tool Corp

Key Events

Petition

petition

Title: Lithium-Based Battery Pack for a High Current Draw, Hand Held Power Tool
Brief Description: The ’173 patent discloses a rechargeable, lithium-based battery pack designed for use with hand-held power tools. The invention centers on a battery pack with a housing, terminals, a locking mechanism to connect to a power tool, and a plurality of battery cells capable of producing an average discharge current of at least 20 amps.

Prior Art Relied Upon: Sato (Japanese Publication No. JP 2002-110254) and Kanai (Application # 2003/0134189).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner argued that Kanai discloses the fundamental structural elements of the claimed invention, including a battery pack for a hand-held power tool with a housing, a plurality of cells, terminals, and a locking assembly. However, Kanai’s cells are not explicitly taught as meeting the 20-amp discharge limitation. Sato was asserted to cure this deficiency by disclosing high-performance lithium-ion cells of a standard "18650" size that are capable of producing a discharge current well over 20 amps (e.g., 22.9 to 30.6 amps).
- Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine Sato's high-current cells with Kanai's battery pack structure. The motivation stemmed from the known industry trend of improving power tool performance. This combination represented a simple substitution of a known, improved component (Sato's cells) into a conventional system (Kanai's pack) to achieve a predictable result—a more powerful battery.
- Expectation of Success: A POSITA would have a high expectation of success because both Sato and Kanai teach the use of the same standard 18650 cylindrical cell geometry, making the substitution physically straightforward and functionally predictable.

Prior Art Relied Upon: Fohr (European Publication No. EP 1 266 725 A1), Sato (Japanese Publication No. JP 2002-110254), and Hallaj (Patent 6,468,689).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner asserted Fohr teaches a base combination of a hand-held power tool with a detachable, rechargeable battery pack that may contain lithium cells and can achieve a continuous current of 20 to 30 amps. Hallaj teaches specific configurations for packaging multiple cylindrical cells into a battery module. Sato again provides the disclosure of high-discharge (over 20 amp) lithium-ion cells.
- Motivation to Combine: A POSITA seeking to build Fohr's high-current battery pack would look to known high-performance cells, such as those in Sato. Hallaj provides a known method for arranging such cells. The motivation was to combine these known elements—a tool system (Fohr), high-performance cells (Sato), and a packaging design (Hallaj)—each performing its known function to create a predictable and more powerful end product.

Prior Art Relied Upon: Johnson (Application # 2004/0257038).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner argued that the Johnson publication is prior art under §102(b) because the ’173 patent is not entitled to its claimed priority date, as explained in the Key Technical Contentions below. Johnson is the publication of an application from which the ’173 patent claims to be a continuation. Petitioner contended that since the Patent Owner had previously argued during prosecution that the claims of the ’173 patent were fully supported by the specification that published as Johnson, the Johnson publication must necessarily teach every element of the claims and therefore anticipates them.
Additional Grounds: Petitioner asserted an additional obviousness challenge against claims 1-5 and 7-13 based on Brotto (Patent 7,273,159), arguing Brotto teaches all elements of the claimed battery pack for a power tool.

Petitioner relied on claim constructions adopted in a related district court litigation involving the ’173 patent for several key terms.
"battery cells being capable of producing an average battery pack discharge current greater than or equal to approximately 20 amps": Construed as the battery cells, when configured in a pack, being capable of producing a current reasonably close to 20 amps or greater over the course of delivering their entire rated capacity. Petitioner argued this limitation is met by prior art cells capable of producing the required current for time periods consistent with the intended use of a hand-held power tool.

A central technical contention was that the ’173 patent is not entitled to an effective filing date prior to December 9, 2008, the filing date of its immediate parent application.
Petitioner argued that the earlier provisional applications (filed in 2002) fail the written description requirement because they do not mention or discuss battery cells capable of producing a 20-amp discharge current.
Furthermore, Petitioner contended that the parent applications fail the enablement requirement for the open-ended claim range of "greater than or equal to approximately 20 amps." The specifications allegedly provide only a conclusory statement of this capability without teaching a POSITA how to make and use a battery that could achieve currents across the full scope of the claim (e.g., 100 amps or more). This alleged priority defect is critical, as it makes the Johnson and Brotto references available as prior art.

Petitioner requests institution of an inter partes review and cancellation of claims 1-13 of Patent 7,944,173 as unpatentable.