DCT
3:24-cv-02122
Power Density Solutions LLC v. Google LLC
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Power Density Solutions, LLC (California)
- Defendant: Google LLC (Delaware)
- Plaintiff’s Counsel: WEEKS NELSON
- Case Identification: 3:24-cv-02122, S.D. Cal., 11/12/2024
- Venue Allegations: Plaintiff alleges venue is proper because Google has a regular and established place of business in the Southern District of California and has committed acts of alleged infringement in the District.
- Core Dispute: Plaintiff alleges that Defendant’s Google Tensor Processing Unit (TPU) servers, which use liquid cooling, infringe a patent related to apparatus and systems for cooling electronic components.
- Technical Context: The lawsuit concerns advanced liquid cooling technologies required for high-density, high-power computer chips, such as those used for artificial intelligence (AI) processing in large-scale data centers.
- Key Procedural History: The complaint does not mention any prior litigation, inter partes review (IPR) proceedings, or licensing history related to the patent-in-suit.
Case Timeline
| Date | Event |
|---|---|
| 1998-12-22 | ’901 Patent Priority Date |
| 2003-04-22 | ’901 Patent Issue Date |
| 2018-05-01 | Approx. launch of Accused (TPUv3) Products |
| 2024-11-12 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
- Patent Identification: U.S. Patent No. 6,552,901, "Apparatus and System for Cooling Electronic Circuitry, Heat Sinks, and Related Components," issued April 22, 2003.
- The Invention Explained:
- Problem Addressed: The patent describes the challenge of thermal constraints limiting the power density and efficiency of electronic components, particularly in space-constrained applications like transportation and high-performance computing. Traditional methods like cold plates or external spray cooling are described as cumbersome, complex, or inefficient. ('901 Patent, col. 1:15-41, 1:50-62).
- The Patented Solution: The invention proposes a system where the electronic component and/or its heat sink are engineered with internal passageways. A cooling fluid is supplied directly into these internal paths, cooling the component from the inside out via conduction, and then exits through ports or nozzles onto the exterior surface, providing further evaporative cooling. ('901 Patent, Abstract; col. 2:60-65). This design integrates the cooling mechanism into the component itself, aiming for more effective heat removal at the source. ('901 Patent, col. 1:53-59).
- Technical Importance: This approach sought to enable the creation of smaller, more powerful, and more cost-effective electronic systems by providing a more efficient method for removing the significant latent heat generated by high-density components. ('901 Patent, col. 1:42-44).
- Key Claims at a Glance:
- The complaint asserts independent claim 16. (Compl. ¶15).
- Essential elements of independent claim 16 include:
- An electronic component.
- A heat sink attached to the component.
- The heat sink has at least one interior passageway and at least one secondary passageway connecting the interior one to an exterior surface.
- A "means for supplying cooling fluid capable of phase change" to the interior passageway.
- A "means for adjusting the rate" of fluid flow so that substantially no fluid is vaporized within the interior passageway.
- A "means for collecting and recycling" the cooling fluid.
- The complaint reserves the right to assert other claims from the ’901 patent. (Compl. ¶16).
III. The Accused Instrumentality
- Product Identification: The "Google version 3 Tensor Processing Units ('TPU' or 'TPUv3') featuring server motherboards with tubing connected to chip heat sinks to facilitate liquid cooling of Google data centers and cloud servers" (the "Accused Devices"). (Compl. ¶8).
- Functionality and Market Context: The Accused Devices are specialized servers designed for AI workloads. (Compl. ¶9). The complaint alleges that their use of liquid cooling is a critical feature that enables Google's processors to run at 100% capacity for AI processing, a significant improvement over previous versions. (Compl. ¶9). The complaint alleges Google implemented this liquid-cooling process to meet the increasing computational demands of AI services, which generate significant heat. (Compl. ¶8). A visual in the complaint shows a motherboard with four distinct chip modules, each fitted with a heat sink and interconnected with tubing labeled "FLUID IN" and "FLUID OUT." (Compl., p. 4). This image depicts a system where a coolant circulates through tubing to heat sinks atop each TPUv3 ASIC chip to remove heat. (Compl. ¶10).
IV. Analysis of Infringement Allegations
The complaint references an infringement chart (Exhibit 2) that was not attached to the publicly filed document. The analysis below is based on the narrative allegations in the complaint.
’901 Patent Infringement Allegations
| Claim Element (from Independent Claim 16) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A system for cooling an electronic component comprising: at least one electronic component; a heat sink attached to said at least one electronic component; | The Accused Devices contain TPUv3 ASIC chips (electronic components), each with a heat sink sitting atop the chip. | ¶10 | col. 12:59-62 |
| said heat sink having at least one interior passageway within said heat sink and at least one secondary passageway in fluid communication with said at least one interior passageway connecting said interior passageway to an exterior surface of said heat sink; | The system brings liquid coolant to the chips, allowing it "to circulate through the tubing and heat sinks to remove heat from the chips." A supporting image shows tubing labeled "FLUID IN" and "FLUID OUT" connected to the heat sinks. | ¶10, p. 4 | col. 12:62-65; col. 13:10-15 |
| means for supplying cooling fluid capable of phase change to said interior passageway; | The complaint alleges Google's system brings "dielectric liquid" to the chips via tubing, as depicted in a photograph with a "FLUID IN" label pointing to the tubing assembly. | ¶10, p. 4 | col. 13:16-18 |
| means for adjusting the rate at which said cooling fluid passes through said interior passageway so that substantially no cooling fluid is vaporized within said interior passageway; | The complaint does not provide sufficient detail for analysis of this element. | col. 13:18-21 | |
| and means for collecting and recycling said cooling fluid. | The complaint alleges the coolant "circulate[s]" and a provided image shows tubing labeled "FLUID OUT," suggesting a collection and recirculation mechanism. | ¶10, p. 4 | col. 13:21-22 |
- Identified Points of Contention:
- Technical Questions: A central technical question will be whether the accused TPUv3 cooling system performs the function recited in the "means for adjusting the rate" limitation. The complaint provides no facts alleging that the system is designed or operated to ensure "substantially no cooling fluid is vaporized within said interior passageway." Evidence on how and where phase change occurs in Google's system will be critical.
- Scope Questions: The interpretation of the means-plus-function limitations under 35 U.S.C. § 112(f) will be a primary legal issue. The court will need to identify the structure disclosed in the ’901 patent that corresponds to the claimed functions (e.g., "means for adjusting the rate") and then determine if the accused Google system contains an equivalent structure. The complaint's visual evidence shows tubing and heat sinks, but discovery will be necessary to determine the internal structure and its correspondence to the patent's disclosure.
V. Key Claim Terms for Construction
- The Term: "means for adjusting the rate at which said cooling fluid passes through said interior passageway so that substantially no cooling fluid is vaporized within said interior passageway"
- Context and Importance: This means-plus-function term is critical because it defines a specific operational mode that distinguishes the invention from other cooling methods. It requires not just adjusting a flow rate, but doing so for the specific purpose of preventing vaporization inside the primary fluid path, implying that cooling within the "interior passageway" is primarily conductive. Infringement will depend on whether Google’s system has a corresponding structure that performs this identical function. Practitioners may focus on this term because the complaint offers no factual allegations to support it, suggesting it may be a key point of non-infringement.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The patent describes a system that accomplishes both conductive and evaporative cooling, which could suggest that the location of vaporization is not rigidly fixed. ('901 Patent, col. 3:1-4). A party might argue the "substantially no" language allows for some incidental vaporization.
- Evidence for a Narrower Interpretation: The claim language is specific about preventing vaporization within the interior passageway. The specification distinguishes the invention from less efficient traditional methods by highlighting more controlled heat removal. ('901 Patent, col. 3:5-15). The patent also describes managing openings and pressure to control cooling, suggesting a specific structural implementation is required to achieve the claimed function. ('901 Patent, col. 4:16-24).
VI. Other Allegations
The complaint does not contain explicit counts for indirect or willful infringement. It includes a request for attorneys' fees under 35 U.S.C. § 285. (Compl. ¶21).
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of claim scope and proof: Can Plaintiff demonstrate that the accused Google TPUv3 cooling system contains a structure corresponding to the patent's "means for adjusting the rate" of fluid flow to prevent internal vaporization? The complaint is silent on this highly specific functional requirement, making it a central evidentiary hurdle.
- A key question will be one of structural correspondence: Does the internal architecture of Google's heat sinks and tubing, once revealed in discovery, map onto the "interior passageway" and "secondary passageway" structures as defined by the claims and described in the ’901 patent specification?