DCT
6:21-cv-00845
Maxell Ltd v. Zhuhai CosMX Battery Co Ltd
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Maxell Holdings, Ltd. (Japan)
- Defendant: Zhuhai CosMX Battery Co., Ltd. (China)
- Plaintiff’s Counsel: Vinson & Elkins LLP
- Case Identification: 6:21-cv-00845, W.D. Tex., 08/13/2021
- Venue Allegations: Plaintiff alleges venue is proper because Defendant is not a resident of the United States and may therefore be sued in any judicial district. The complaint also alleges Defendant conducts substantial business in Texas.
- Core Dispute: Plaintiff alleges that Defendant’s lithium-ion batteries infringe four patents related to the chemical composition of battery electrodes, electrolyte additives, and the physical structure of battery separators.
- Technical Context: The technology concerns improvements in the energy density, safety, and cycle life of lithium-ion batteries, which are fundamental power sources for a vast range of consumer electronics.
- Key Procedural History: The complaint alleges that Plaintiff provided Defendant with notice of infringement for at least two of the patents-in-suit via a letter dated May 19, 2020, which offered to engage in licensing discussions.
Case Timeline
| Date | Event |
|---|---|
| 2006-10-26 | Earliest Priority Date for U.S. Patent No. 8,691,446 |
| 2006-10-26 | Earliest Priority Date for U.S. Patent No. 9,350,019 |
| 2007-03-20 | Earliest Priority Date for U.S. Patent No. 9,077,035 |
| 2007-10-03 | Earliest Priority Date for U.S. Patent No. 9,166,251 |
| 2014-04-08 | U.S. Patent No. 8,691,446 Issues |
| 2015-07-07 | U.S. Patent No. 9,077,035 Issues |
| 2015-10-20 | U.S. Patent No. 9,166,251 Issues |
| 2016-05-24 | U.S. Patent No. 9,350,019 Issues |
| 2020-05-19 | Plaintiff allegedly sent notice letter to Defendant |
| 2021-08-13 | Complaint Filed |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 8,691,446 - "Nonaqueous Secondary Battery And Method Of Using The Same," issued April 8, 2014
The Invention Explained
- Problem Addressed: The patent describes a need to increase the electric capacity of lithium-ion batteries beyond what is achievable with conventional lithium cobalt oxide (LiCoO₂) chemistry, particularly when charging to higher voltages. Charging conventional batteries to higher voltages can cause the crystalline structure of the active material to decay, shortening the battery's cycle life and deteriorating its thermal stability (US 8,691,446 B2, col. 1:49-2:6).
- The Patented Solution: The invention proposes a nonaqueous secondary battery that combines three key features: (1) a positive electrode containing a lithium-containing transition metal oxide doped with specific elements like Mg, Ti, or Al; (2) a positive electrode mixture layer with a high density of at least 3.5 g/cm³ to increase the amount of active material; and (3) a nonaqueous electrolyte containing a compound with at least two nitrile groups. The nitrile compound allegedly forms a protective film on the positive electrode, suppressing reactions with the electrolyte and preventing gas generation, thereby improving safety and storage characteristics at high temperatures (’446 Patent, Abstract; col. 6:26-40).
- Technical Importance: This combination of material chemistry, physical density, and electrolyte additives was aimed at enabling lithium-ion batteries with higher energy density and improved stability, which are critical for increasingly power-hungry portable electronics (’446 Patent, col. 1:11-34).
Key Claims at a Glance
- The complaint asserts independent claim 1 (Compl. ¶66).
- Claim 1 Elements:
- A nonaqueous secondary battery comprising a positive electrode, a negative electrode, and a nonaqueous electrolyte.
- The positive electrode contains at least two lithium-containing transition metal oxides with different average particle sizes and different elemental compositions.
- The lithium-containing transition metal oxide with the smallest average particle size is represented by a specific chemical formula (1) with defined elemental ratios.
- The positive electrode mixture layer has a density of at least 3.5 g/cm³.
- The nonaqueous electrolyte contains a compound having at least two nitrile groups in the molecule.
U.S. Patent No. 9,350,019 - "Nonaqueous Secondary Battery And Method Of Using The Same," issued May 24, 2016
The Invention Explained
- Problem Addressed: As a divisional of the application that led to the ’446 Patent, this patent addresses the same technical challenge: improving the capacity, cycle life, and safety of lithium-ion batteries, especially when operating at higher voltages (US 9,350,019 B2, col. 1:49-2:6).
- The Patented Solution: The solution is structurally similar to that of the ’446 patent, focusing on a positive electrode with mixed active materials and a specific electrolyte. However, the claims of the ’019 patent introduce a more specific limitation on the chemical composition. In addition to the requirements of using mixed oxides and a nitrile-containing electrolyte, asserted claim 1 specifies that the content of magnesium (Mg) in the smallest-particle-size oxide must be within a narrow range of 0.15% to less than 2% by mole, based on the amount of the primary transition metal element (’019 Patent, col. 27:26-33).
- Technical Importance: This invention reflects a more granular approach to optimizing battery performance by precisely controlling the amount of a specific stabilizing element (Mg) within the cathode material’s crystal structure.
Key Claims at a Glance
- The complaint asserts independent claim 1 (Compl. ¶84).
- Claim 1 Elements:
- A nonaqueous secondary battery with a positive electrode, a negative electrode, and a nonaqueous electrolyte.
- The positive electrode contains at least two lithium-containing transition metal oxides with different average particle sizes.
- The smallest average particle size oxide is represented by a specific chemical formula (1).
- A specific content of Mg in the formula (1) oxide is claimed: from 0.15% by mole to less than 2% by mole based on the amount of the metal element M¹.
- The positive electrode mixture layer has a density of at least 3.5 g/cm³.
- The nonaqueous electrolyte contains a compound having at least two nitrile groups.
U.S. Patent No. 9,077,035 - "Nonaqueous Secondary Battery And Method Of Using The Same," issued July 7, 2015
- Technology Synopsis: This patent is directed to a nonaqueous secondary battery having a positive electrode that comprises at least two lithium-containing transition metal oxides with different average particle sizes. The invention specifies distinct chemical formulas and particle size ranges for the smallest and largest particle size oxides and further requires the electrolyte to contain a fluorine-containing organic solvent to improve performance and stability (US 9,077,035 B2, Abstract; col. 33:2-34).
- Asserted Claims: Claim 1 (Compl. ¶102).
- Accused Features: The complaint alleges that the positive electrodes of the accused battery cells contain mixed-particle-size oxides and that their electrolytes contain a fluorine-containing organic solvent, meeting the limitations of the asserted claim (Compl. ¶105, ¶107, ¶109).
U.S. Patent No. 9,166,251 - "Battery Separator And Nonaqueous Electrolyte Battery," issued October 20, 2015
- Technology Synopsis: This patent discloses a battery separator with a multilayer structure designed to enhance battery safety at high temperatures. The separator comprises a "heat-resistant layer" containing specific heat-resistant fine particles and a "shutdown layer" made of a thermoplastic resin that melts in a specific temperature range (135° C. to 150° C.) to close its pores and stop ion flow, thereby preventing thermal runaway. The patent claims specific thicknesses, particle sizes, and compositions for these layers (US 9,166,251 B2, Abstract; col. 40:8-51).
- Asserted Claims: Claims 1 and 10 (Compl. ¶121).
- Accused Features: The complaint alleges that the separators within the accused battery cells embody the claimed multilayer structure, including a heat-resistant layer and a shutdown layer with the specified physical and functional properties (Compl. ¶125, ¶128, ¶131).
III. The Accused Instrumentality
- Product Identification: The accused products are lithium-ion battery ("LIB") cells manufactured by Defendant CosMX, including at least model numbers CA575576G-1, CA486566G, and CA395876G (Compl. ¶18, ¶56).
- Functionality and Market Context: These LIB cells are rechargeable power sources incorporated into various consumer electronic products, such as the Dell d/b/a Alienware 99Wh Type 9NJM1 notebook battery, the HP KC04XL laptop battery, and the Asus ZenFone Live L1 smartphone (Compl. ¶18). The complaint provides a photograph of a disassembled Dell notebook battery, identifying the accused CosMX LIB Cell No. CA575576G-1 inside (Compl. p. 6). Defendant CosMX is positioned in the complaint as one of the world's top suppliers of polymer lithium-ion batteries for major electronics companies (Compl. ¶15).
IV. Analysis of Infringement Allegations
U.S. Patent No. 8,691,446 Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a positive electrode contains, as an active material, at least two lithium-containing transition metal oxides having different average particle sizes | The accused cells allegedly contain a positive electrode active material with at least two lithium-containing transition metal oxides that have different average particle sizes. | ¶69 | col. 8:35-44 |
| said at least two lithium-containing transition metal oxides... have different compositions of elements between them | The accused cells' transition metal oxides allegedly have different elemental compositions. | ¶69 | col. 9:8-9 |
| said lithium-containing transition metal oxide having the smallest average particle size is a lithium-containing transition metal oxide represented by the formula (1)... | The smallest particle size oxide in the accused cells allegedly satisfies the specific elemental ratios defined in Formula (1) of the patent. | ¶69 | col. 9:60-10:5 |
| the positive electrode mixture layer has a density of at least 3.5 g/cm³ | The positive electrode mixture layer in the accused cells allegedly has a density of at least 3.5 g/cm³. A photo of an accused HP battery cell is provided as evidence (Compl. p. 8). | ¶69 | col. 8:58-61 |
| the nonaqueous electrolyte contains a compound having at least two nitrile groups in the molecule | The electrolyte in the accused cells allegedly contains a compound with at least two nitrile groups. A photo of an accused Asus smartphone cell is provided as evidence (Compl. p. 12). | ¶69 | col. 6:26-29 |
U.S. Patent No. 9,350,019 Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| the positive electrode contains, as an active material, at least two lithium-containing transition metal oxides having different average particle sizes | The positive electrode active material in the accused cells allegedly contains at least two lithium-containing transition metal oxides with different average particle sizes. | ¶87 | col. 8:35-44 |
| said lithium-containing transition metal oxide having the smallest average particle size is a lithium-containing transition metal oxide represented by the formula (1)... | The smallest particle size oxide in the accused cells is alleged to conform to the elemental ratios specified in Formula (1). | ¶87 | col. 9:60-10:5 |
| a content of Mg in the formula (1) is from 0.15% by mole to less than 2% by mole based on an amount of the metal element M¹ | The amount of magnesium in the smallest particle size oxide in the accused cells allegedly falls within the claimed molar percentage range. | ¶87 | col. 27:26-33 |
| the positive electrode mixture layer has a density of at least 3.5 g/cm³ | The positive electrode mixture layer in the accused cells is alleged to have a density of at least 3.5 g/cm³. | ¶87 | col. 8:58-61 |
| the nonaqueous electrolyte contains a compound having at least two nitrile groups in the molecule | The electrolyte in the accused cells is alleged to contain a compound with at least two nitrile groups. | ¶87 | col. 6:26-29 |
- Identified Points of Contention:
- Evidentiary Questions: The complaint’s allegations regarding the specific chemical compositions, elemental ratios, and physical densities of the accused batteries are made "upon information and belief" and based on "preliminary analysis" (Compl. ¶69, ¶87). A central point of contention will be whether Plaintiff can prove through discovery and expert testing that the accused products actually meet these highly specific claim limitations.
- Scope Questions: For both the ’446 and ’019 patents, a key question will be whether the specific mixture of lithium-containing transition metal oxides used in the accused products falls within the scope of the chemical formulas recited in the claims, including the specific ranges for each element.
V. Key Claim Terms for Construction
The Term: "average particle size"
- Context and Importance: The claims of the ’446, ’019, and ’035 patents all require the use of at least two active materials having "different average particle sizes." The method for measuring this property is therefore critical to determining infringement. Practitioners may focus on this term because different measurement techniques could yield different results, potentially moving an accused product in or out of the claim scope.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The term itself is generally understood in the art, which might support using any commercially reasonable measurement standard.
- Evidence for a Narrower Interpretation: The specification of the ’446 Patent explicitly defines "average particle size" as a "50% diameter value (d₅₀), that is, an median diameter, read from an integral fraction curve based on volumes," and identifies a specific piece of equipment (MICROTRAC particle size analyzer HRA 9320) for making the measurement (’446 Patent, col. 8:46-52). This detailed definition provides strong evidence for a narrow and specific construction.
The Term: "positive electrode mixture layer has a density of at least 3.5 g/cm³"
- Context and Importance: This limitation from the ’446 and ’019 patents sets a specific, quantitative threshold for a physical property of the accused product. The determination of infringement will depend on whether the accused products meet this numerical requirement, making the methodology for measuring density a crucial issue.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: A party could argue for any standard industry method for measuring electrode density.
- Evidence for a Narrower Interpretation: The ’446 Patent specification provides a detailed, multi-step procedure for measuring this density, involving cutting a sample, weighing it on an electronic balance, measuring its thickness at ten points with a micrometer, calculating the volume, and then dividing the weight by the volume (’446 Patent, col. 8:1-19). This explicit instruction on how to determine the claimed value will likely be central to how the court construes this term.
VI. Other Allegations
- Indirect Infringement: The complaint alleges both induced and contributory infringement for all four asserted patents. Inducement is based on allegations that CosMX sells the LIBs with knowledge and intent that its customers will incorporate them into infringing end-products for sale in the U.S., supported by actions such as creating distribution channels and providing technical support (Compl. ¶75, ¶93, ¶112, ¶134). Contributory infringement is based on allegations that the accused LIBs are a material part of the patented inventions, are not staple articles of commerce, and are especially designed for use in an infringing manner (Compl. ¶76, ¶94, ¶113, ¶135).
- Willful Infringement: The complaint alleges willful infringement for all asserted patents. For the ’446 and ’019 patents, willfulness is based on alleged pre-suit knowledge stemming from a May 19, 2020 notice letter (Compl. ¶65, ¶83). For the ’035 and ’251 patents, willfulness is based on knowledge acquired no later than the date of service of the complaint (Compl. ¶101, ¶120).
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of evidentiary proof: can the Plaintiff, through reverse engineering and expert analysis, demonstrate that the internal chemistry and physical structure of Defendant's mass-produced battery cells meet the highly specific quantitative limitations recited in the patent claims—including precise elemental ratios, particle size distributions, electrode densities, and separator properties? The complaint's phrasing suggests these facts are not yet definitively established.
- A key question for damages will be one of willfulness: given the alleged pre-suit notice for two of the patents, did the Defendant act with objective recklessness by continuing its allegedly infringing conduct after May 2020? The answer will determine the potential for enhanced damages.
- A central technical question will be one of structural and functional correspondence: for the ’251 patent, does the separator in the accused products perform as a true "multilayer structure" with distinct "heat-resistant" and "shutdown" layers that operate within the claimed temperature ranges, or does it function in a fundamentally different way?