Obviousness

This analysis will assess the obviousness of US patent 12015118 under 35 U.S.C. § 103, considering combinations of prior art references and the motivation a person having ordinary skill in the art (PHOSITA) would have had to combine them. The analysis will focus on the independent claims (Claims 1, 10, and 19) as they broadly define the invention.

A PHOSITA is considered to have ordinary creativity and common sense and their knowledge includes both explicit teachings and what the art reasonably suggests. Motivation to combine prior art can stem from various factors, including market forces, known needs or problems in the field, and a general desire to improve on existing technology. This includes a general motivation to increase energy efficiency, which is not inherently suspect. Obviousness determinations require clear, fact-based reasoning to support the motivation to combine.

The patent US12015118 addresses the safety problem of lithium-ion batteries being punctured by external forces, specifically aiming to avoid internal short circuits, particularly the dangerous positive electrode current collector-negative electrode active material layer short circuit, while maintaining high energy density.

The "Prior art keywords" listed on US12015118B2 include "active material," "lithium," "layer," "material layer," and "nickel cobalt." This suggests that prior art in these areas is relevant.

Potential Combinations of Prior Art and Motivation to Combine

Combination 1: US9543568B2 (Sung et al.) + General Knowledge in Battery Safety

• US9543568B2 (Sung et al.): This patent explicitly discloses an "electrode including a multi-layered electrode active material layer and a secondary battery including the same." It states that forming an electrode active layer as a multi-layered coating can improve performance by decreasing battery resistance and notes that "researches on lithium secondary batteries having a high energy density are actively conducted." Sung et al. also teach that each layer of the multi-layered structure can be formed using the same or different active material components, and that an active material layer making direct contact with the collector or the uppermost layer can use an active material with better electric conductivity or an electrode slurry with more conductive materials or a more uniform particle size.

• Motivation to Combine: A PHOSITA, aware of the ongoing need to improve lithium-ion battery safety and energy density (as highlighted in US12015118's background), would be motivated to apply the multi-layered electrode concept taught by Sung et al. to enhance safety, particularly against internal short circuits. The general desire to improve prior art, address known problems, and increase energy efficiency are all valid motivations. The concept of providing a coating with higher resistivity on the current collector surface to prevent direct contact during nail penetration is a known approach to avoid dangerous short circuits. US12015118 itself mentions that "preferentially avoiding such a short circuit mode of the positive electrode current collector-negative electrode active material layer is the most direct means for improving the safety of the lithium-ion battery penetrating through nails." The PHOSITA would consider applying a layer, as taught by Sung et al., specifically for this safety purpose.

  The "active material layer 3" (first active material layer) in US12015118 is described as being formed between the current collector and the second active material layer to increase adhesion and protect the current collector, preventing short circuits during nail penetration. Sung et al. already discusses forming a multi-layered electrode with specific active materials for the layer making direct contact with the collector to improve electrical conductivity or particle uniformity. It would be an obvious design choice for a PHOSITA, given the safety concerns, to select materials and parameters for this inner layer (the "first layer" of US12015118) to primarily provide mechanical protection and electrical insulation properties (i.e., higher resistivity), rather than solely focusing on conductivity or particle uniformity, while still being an active material. This adaptation would be driven by the clear motivation to improve battery safety against internal short circuits.

Combination 2: US20240088354A1 (Yang et al.) + US9543568B2 (Sung et al.)

• US20240088354A1 (Yang et al.): This patent application describes a battery electrode with a "layered structure" and specifically mentions "a first coating adjacent to the first metal foil" and "a second coating adjacent to the second metal foil." It also discusses "improving burring and short circuit protection." The abstract also mentions a thermoplastic polymer layer between metal foils and coatings, and the specification further describes a "first lithium cobalt oxide coating adjacent to the first aluminum foil" and a "second lithium cobalt oxide coating adjacent to the second aluminum foil."
• US9543568B2 (Sung et al.): As discussed above, Sung et al. teaches the general concept of multi-layered active material layers for improved battery performance.
• Motivation to Combine: Yang et al. explicitly teaches a layered structure for electrodes with the goal of improving short circuit protection. Sung et al. provides a broader teaching of multi-layered active material layers. A PHOSITA would be motivated to combine the specific short-circuit protection aspects of Yang et al. with the general multi-layering principles of Sung et al. to achieve a more robust and safer electrode design. The general desire to improve the safety and performance of lithium-ion batteries would drive this combination.

Combination 3: US9543568B2 (Sung et al.) + Stanford Researchers' Work on Interfacial Layers (from 2018)

• US9543568B2 (Sung et al.): Again, the teaching of a multi-layered electrode active material layer.
• Stanford Researchers' Work (from 2018): Stanford researchers developed "high ionic conductivity thin films (LiAlO2, LiAlF4) to stabilize lithium ion battery electrodes without sacrificing power density." These "atomic layer deposited interfacial layer reduces side reactions between electrolyte and electrode when operated at a wide electrochemical window, maintains power density, and improves energy density – making a safer battery." These thin films are "electrochemically inert, chemically stable, lithium ion conductive and can be applied to various battery cathodes." They successfully tested this on NMC-811 and LiCoO2 electrodes.
• Motivation to Combine: The Stanford research, published prior to the priority date of US12015118 (which is February 26, 2018), clearly demonstrates a motivation to create safer batteries by using interfacial layers that improve stability, maintain power density, and improve energy density. A PHOSITA, seeking to enhance battery safety and performance, would look to implement such protective interfacial layers. Combining this knowledge with Sung et al.'s teaching of multi-layered active material layers would be a logical step. The interfacial layers described by Stanford could be incorporated as one of the active material layers (e.g., the first active material layer of US12015118) or as a coating within such a multi-layered structure to provide enhanced safety features, such as preventing direct contact between the current collector and the negative electrode active material during a nail penetration event. The known problem of internal short circuits and the desire for safer, higher energy density batteries would strongly motivate this combination.

Obviousness of Specific Claim Limitations

• "A particle size of 90% accumulative volume of the first material is less than 40 μm": US12015118 states that "in the granularity distribution of the positive electrode active material of the first active material layer on a volume basis, a particle size that reaches volume accumulation of 90% from a small particle size (Dv90) ranges below 40 μm." The patent further explains that smaller particles in the first active material layer are desired "to achieve higher coverage and adhesion on the positive electrode current collector (aluminum foil)." A PHOSITA would understand that smaller particle sizes generally lead to better coverage and adhesion for coatings. Given the clear motivation to protect the current collector (as established above), selecting a particle size for the first active material layer that ensures good coverage and adhesion, such as a Dv90 less than 40 μm, would be an obvious design choice. The examples in US12015118 itself demonstrate various Dv50 and Dv90 values for the first active material layer, with results showing good nail penetration performance within the specified range (e.g., Examples 1-20, 22-29, 31-44, 45-50 all have Dv90 equal to or less than 40 μm and 9/10 or 10/10 PASS rate).
• "A total compaction density of the first layer and the second layer is greater than 3.2 g/cc": US12015118 explicitly states that "To ensure the energy density of a lithium-ion battery, it is required that the positive electrode has a higher compaction density, the compaction density of the first active material layer is greater than 2.8 g/cc, the compaction density of the second active material layer is greater than 3.3 g/cc and the compaction density of the all active material layers is greater than 3.2 g/cc." Achieving higher compaction density in battery electrodes is a well-known goal in the art for increasing energy density. A PHOSITA would recognize the importance of compaction density for energy density and would strive to achieve high compaction densities for both individual layers and the overall active material layer. The specific values provided, therefore, represent optimization within known engineering principles for improving battery performance, rather than an inventive step.

Conclusion on Obviousness

Based on the above, the independent claims of US12015118, particularly Claim 1, appear to be obvious in light of combinations of prior art references. The core concept of a multi-layered active material layer for battery electrodes was known (Sung et al.). The motivation to use such layering to enhance safety and prevent short circuits, especially at the interface with the current collector, was a recognized problem in the field, and solutions involving protective layers or coatings were also known (Yang et al., Stanford researchers). A PHOSITA, driven by the persistent need for safer and higher energy density lithium-ion batteries, would have been motivated to combine these teachings. The specific parameters related to particle size (Dv90 < 40 μm) and compaction density (> 3.2 g/cc) represent optimizing known features within expected ranges to achieve desired battery performance and safety, which would be considered within the ordinary skill of a person in the art.