Obviousness

US patent 11923498, titled "Lithium-ion battery having desirable safety performance," introduces specific insulating glue layers in a lithium-ion battery design that utilizes recesses for accommodating leads in the positive and negative electrode active material layers. An analysis under 35 U.S.C. § 103 suggests that the claimed invention would have been obvious to a person having ordinary skill in the art (POSITA) based on combinations of existing prior art, motivated by known safety concerns.

Primary Prior Art for Recessed Lead Structure

The patent itself acknowledges the existence of prior art disclosing the fundamental structure of recessed leads. Specifically, it states: "Chinese patent publication numbers CN 202495523U and CN 201087907Y each discloses a lithium-ion battery which defines a recess on a positive plate and/or the negative plate to receive a lead therein." This establishes that the concept of creating recesses in the active material layers (positive and/or negative) to embed leads and thereby reduce battery thickness and improve energy density was known in the art prior to the priority date of US11923498 (January 17, 2014).

Problem Addressed by US11923498

The present patent explicitly identifies a deficiency in these prior art recessed lead designs: "there is no insulating layer provided on the positive area corresponding to the positive recess or the negative recess, internal short circuit and lithium precipitation may potentially occur to the lithium-ion battery, which will inevitably affect the safety performance of the lithium-ion battery." This statement highlights the known problem of internal short circuits and lithium precipitation arising from the lack of insulation in these recessed areas.

Secondary Prior Art for Insulating Layers and Safety

A POSITA would be motivated to address these identified safety issues using known solutions for electrical insulation in lithium-ion batteries. Several cited prior art documents, by their titles, suggest a general understanding of enhancing electrical insulation in batteries:

• US20110027636A1 (Lg Chem, Ltd.) is titled "Battery having enhanced electrical insulation capability."
• JP2007165224A (Matsushita Electric Ind Co Ltd) is titled "Non-aqueous electrolyte secondary battery."
• US20070172736A1 (Masato Fujikawa) is titled "Lithium secondary battery."

Assuming these references (or others in the extensive "Citations" list predating 2014-01-17 that focus on battery safety or insulation) disclose the use of insulating layers or glue to prevent internal short circuits or lithium precipitation in lithium-ion batteries, they would provide the necessary secondary reference(s).

Obviousness Argument

A combination of the teachings from CN 202495523U or CN 201087907Y with the general knowledge of enhancing electrical insulation in batteries, as evidenced by references like US20110027636A1, would render the claims of US11923498 obvious.

1. Starting Point: A POSITA would begin with a lithium-ion battery design featuring recessed positive and negative leads, as taught by CN 202495523U and CN 201087907Y, to achieve the recognized benefits of increased energy density.
2. Identified Problem: The patent itself clearly articulates the "long-felt need" or "known problem" associated with these recessed designs: the potential for internal short circuits and lithium precipitation due to the absence of insulating layers in critical areas around the leads and recesses.
3. Motivation to Combine: Faced with this known safety deficiency, a POSITA would be strongly motivated to implement known insulating techniques to mitigate the risks. The objective of improving safety by preventing internal short circuits and lithium precipitation is a common goal in battery technology. Therefore, applying conventional insulating materials, such as glue layers, to cover exposed conductive parts and active material edges in the recessed areas would be a logical and predictable design modification.
4. Specific Claim Features:
   • First insulating glue layer on the positive lead (Claim 1, 9, 17): Covering the top surface (and lower surface, as clarified by the detailed description and Claim 9) of the positive lead with an insulating glue layer to prevent short circuits is a straightforward application of insulation principles. The detailed description states that the insulating glue layer formed on the lower surface of the positive lead "entirely covers the blank positive current collector in the first recess," which directly addresses preventing shorts from exposed current collector material.
   • Second insulating glue layer on the positive electrode active material layer opposite the second recess (Claim 1, 9, 17): Placing an insulating glue layer on the surface of the positive active material layer corresponding to the negative lead's recess is a direct response to preventing short circuits and lithium precipitation in that specific opposing area.
   • Dimensions of the second insulating glue layer (Claim 1, 9, 17): The requirement that the second insulating glue layer has a width and length larger than the second recess is a matter of routine engineering for ensuring complete and effective coverage and insulation of the critical area.

Conclusion

Given that the core problem (internal short circuit and lithium precipitation in recessed lead designs) was recognized, and the general solution (using insulating layers to prevent such issues) was known in the art, a POSITA would have been motivated to combine the recessed lead structure of references like CN 202495523U and CN 201087907Y with conventional insulating measures to improve safety. The specific placement and sizing of the insulating glue layers as claimed in US11923498 represent predictable design choices within the skill of an ordinary artisan seeking to address known safety concerns in a recessed electrode design. Therefore, the claims of US11923498 are likely obvious under 35 U.S.C. § 103.