{"schema_version":1,"experiment_id":"eoa_inverse_innovation_exp09_archetype_breadth150_20260804","cell_id":"invariant_mode_decomposition_design__chemistry_materials","arm":"BREADTH_PROBE_ONE_SHOT","candidate_id":"invariant_mode_decomposition_design__chemistry_materials__P1","proposal_index":1,"version":0,"title":"Modal Control of Coupled Degradation During Silicon–Graphite Cell Formation","problem":"During formation cycling of silicon–graphite lithium-ion cells, engineers tune current, voltage holds, temperature, and rest periods against individual measurements such as capacity or impedance. Yet solid-electrolyte-interphase growth, lithium consumption, electrode swelling, impedance, and capacity slippage evolve as coupled combinations. A formation recipe can therefore look acceptable on every single-variable limit while repeatedly amplifying a hidden degradation direction that becomes visible only after subsequent cycles.","actors":["Cell-formation process engineer","Battery materials scientist","Electrochemical test technician","Pilot-line quality engineer","Cell safety owner"],"observable_state":"After each standardized formation segment, each pilot cell has a traceable state vector comprising charge and discharge capacity, coulombic inefficiency, differential-capacity peak positions, pulse-derived resistance, relaxation time constants, thickness change, and temperature excursion. The diagnostic signature of the problem is a repeatable joint movement across several of these measurements whose amplitude grows from one segment to the next even though no individual measurement has yet crossed its release limit.","consequence":"Cells can leave formation with a coupled degradation process still growing, producing avoidable lithium loss, swelling, impedance growth, or early capacity decline during later qualification while coordinate-by-coordinate recipe adjustments obscure which combination is being amplified.","affected_objective":"Select a formation protocol that damps safety- and durability-relevant coupled state changes while preserving required electrochemical formation, with unexplained residual behavior kept visible.","intervention":"On an instrumented pilot lot, define one formation segment as the transformation from one diagnostic state vector to the next. Fit a bounded local linear transition model separately within a declared temperature, cell-design, and state-of-charge window; eigendecompose it; and rank modes by estimated gain, persistence, safety consequence, and stability across cells. For any weakly damped or growing mode, perform a predeclared modal sensitivity sweep using only approved small changes to formation current, voltage-hold duration, rest duration, and chamber temperature. Choose the protocol change whose measured state displacement projects against that mode without materially exciting other concerning modes. Reconstruct held-out transitions, retain residuals, and suspend modal control when reconstruction error, mode drift, or mode coupling exceeds preset limits.","structural_mapping":[{"archetype_element":"Transformation Scope","domain_realization":"One approved formation segment mapping pre-segment electrochemical, mechanical, and thermal measurements to the next diagnostic snapshot."},{"archetype_element":"State-Vector Definition","domain_realization":"Capacity, coulombic inefficiency, differential-capacity features, resistance, relaxation constants, thickness, and temperature, with units and sensor provenance retained."},{"archetype_element":"Invariant Mode Basis","domain_realization":"Approximately invariant combinations of measured cell-state changes under repeated formation segments."},{"archetype_element":"Modal Gain Spectrum","domain_realization":"Estimated eigenvalues indicating whether each coupled formation-state direction decays, persists, oscillates, reverses, or grows."},{"archetype_element":"Dominant Mode Selection Rule","domain_realization":"A mode becomes action-relevant only if its gain or persistence clears a predeclared threshold, it is stable across resampling, and its mapped variables carry durability or safety significance."},{"archetype_element":"Stable/Unstable Mode Partition","domain_realization":"Modes are classified as damped, weakly damped, persistent, oscillatory, or growing within the declared formation window."},{"archetype_element":"Modal Intervention Map","domain_realization":"Small approved changes in current, voltage-hold time, rest time, and temperature are mapped to their projections on action-relevant modes."},{"archetype_element":"Reconstruction Residual Check","domain_realization":"Predicted post-segment state is compared with held-out measured state; omitted chemistry, nonlinear behavior, and sensor anomalies remain explicit residuals."},{"archetype_element":"Mode Drift Monitor","domain_realization":"Mode direction, gain, and reconstruction error are rechecked across lots and after material, electrolyte, equipment, or ambient changes."},{"archetype_element":"Interpretation Scope Contract","domain_realization":"Modes are treated as local empirical dynamics for the tested cell design and formation window, not as universal electrochemical species or reaction pathways."}],"mechanism_mapping":[{"mechanism_slug":"eigendecomposition_workflow","role":"Extracts coupled directions and scalar gains from the fitted local formation-state transition matrix.","counterfactual_removal":"Without eigendecomposition, decisions revert to separate measurement trends and cannot identify the jointly amplified direction."},{"mechanism_slug":"modal_sensitivity_sweep","role":"Tests which approved protocol perturbation damps the concerning mode and whether it excites another mode.","counterfactual_removal":"Without the sweep, a mode may be recognized but there is no empirical map from available controls to that mode."},{"mechanism_slug":"residual_reconstruction_test","role":"Checks the modal model on withheld segment transitions and exposes behavior not represented by selected modes.","counterfactual_removal":"Without residual testing, a convenient low-order decomposition could govern formation despite missing nonlinear or unmeasured degradation."},{"mechanism_slug":"spectral_gap_monitor","role":"Determines whether selected action-relevant modes remain distinguishable from neighboring modes across resampling and lots.","counterfactual_removal":"Without this monitor, unstable rotations among nearly equal modes could be mistaken for persistent physical structure."}],"causal_chain":["Repeated formation segments transform a multivariate electrochemical, mechanical, and thermal cell state.","Coupled degradation can align with a direction not visible in any single measured coordinate.","A fitted local transition model makes that repeated transformation explicit.","Eigendecomposition reveals whether the coupled direction is damped, persistent, or growing and maps it back to measured variables.","A bounded sensitivity sweep identifies an approved protocol perturbation whose state response opposes the concerning mode.","Applying that perturbation during a pilot formation run should reduce the mode's post-segment amplitude if the model is causally useful.","Held-out reconstruction, residual, cross-cell stability, and drift checks determine whether the modal interpretation remains fit for use."],"baseline":"The baseline is the current approved formation recipe, evaluated with the same diagnostic schedule and existing coordinate-level release limits. Engineers investigate excursions measurement by measurement and adjust one formation parameter at a time, without estimating a repeated state-transition operator or testing control effects in modal coordinates.","nearest_rivals":["Multivariate statistical process control, which can flag correlated excursions but does not necessarily model their gain under repeated formation segments or select controls by modal damping.","Principal-component monitoring of formation data, which ranks variance but need not distinguish growing from decaying directions under the segment-to-segment transformation.","Design-of-experiments recipe optimization, which estimates factor-to-outcome effects but can omit the evolving internal state and its stable or unstable modes.","Electrochemical equivalent-circuit fitting, which provides interpretable parameters but does not by itself decompose the repeated joint evolution of electrochemical, thermal, and mechanical state."],"remaining_contrastive_claim":"The candidate is specifically a closed-loop use of a segment-to-segment transformation: identify a coupled state direction by its scalar response under repetition, test available controls in that modal direction, and retain reconstruction and drift limits. Merely finding correlated variables, fitting cell parameters, or optimizing an endpoint does not instantiate that causal structure.","authority_safety":{"decision_authority":"The battery materials scientist may recommend a pilot protocol; the formation process owner and cell safety owner must jointly approve parameter bounds and execution. Existing production release authority remains unchanged.","authorized_first_step":"Run an offline analysis and then, only if its predeclared checks pass, a small instrumented pilot using already-qualified equipment, cells designated for development, and protocol perturbations inside existing safety and equipment envelopes.","excluded_actions":["Changing production formation recipes","Releasing pilot cells for sale or field use","Exceeding validated voltage, current, temperature, pressure, or swelling limits","Suppressing existing alarms, interlocks, inspections, or release tests","Treating a statistical mode as an identified chemical reaction without independent evidence"],"halt_rollback":"Stop the pilot on any existing safety alarm, abnormal swelling or heating, residual-limit breach, unstable mode estimate, or excitation of another concerning mode. Return subsequent cells to the approved baseline recipe, quarantine affected development cells, preserve raw data, and require safety-owner review before resumption."},"negative_tests":{"strongest_counterevidence":"The allegedly growing mode changes direction or gain substantially under cell resampling, disappears when sensor drift and normalization are corrected, lacks a spectral separation from neighboring modes, or fails to reconstruct held-out segment transitions.","problem_falsifier":"Under the baseline recipe, cross-cell data show no repeatable coupled direction that grows or remains weakly damped within the declared formation window; later qualification failures are instead explained by a single observable defect, random manufacturing variation, or behavior outside the measured transformation.","intervention_falsifier":"A protocol perturbation predicted to oppose the concerning mode does not reduce its subsequent amplitude relative to concurrent baseline cells, or it reduces the fitted amplitude only through measurement scaling while raw durability- and safety-relevant trajectories do not move consistently.","risks":["A local linear model may conceal nonlinear thresholds or irreversible side reactions.","Nearly equal eigenvalues may make mode direction unstable and intervention mapping unreliable.","Sensor normalization, missing data, or shared temperature drift may create an artificial mode.","Damping one measured mode may excite an unmeasured or residual degradation pathway.","Small development-lot variation may cause overfitting to particular cells, electrolyte batches, or equipment.","The mathematical mode may be given an unjustified chemical interpretation."]},"next_evidence_step":"Using one existing instrumented development dataset, predeclare the state variables, formation window, normalization, gain threshold, spectral-gap rule, reconstruction-error budget, and cross-cell resampling criterion. Fit the transition model on part of the cells and test mode stability and one-step reconstruction on held-out cells. If those checks pass, run one bounded pilot lot split between the approved baseline and a single safety-approved perturbation selected by the modal sensitivity map; compare the predeclared modal-amplitude trajectory and all existing safety measurements, without changing production practice.","prior_art_status":"UNSEARCHED","diversity_from_prior_proposals":"Not assessed because runtime isolation prohibits inspecting other proposals; this candidate was derived solely from the supplied archetype and chemistry-and-materials domain card.","revision_record":{"parent_version":null,"progress_targets_addressed":[],"conceptual_changes":[],"operational_changes":[],"evidence_changes":[],"claim_changes":[]}}