{ "node": { "id": "term:calendar-aging", "type": "Term", "label": "Calendar aging", "properties": { "id": "calendar-aging", "name": "Calendar aging", "section": "topic-aging", "definition": "Degradation that happens with time even when a cell is not cycled — in storage, for example. 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It protects the electrode from further reaction but grows slowly for the whole life of the cell, consuming cyclable lithium.", "related": [ "passivation", "formation", "calendar-aging", "loss-of-lithium-inventory", "cei" ], "lesson": "fundamentals/battery-aging/#sei", "url": "https://lemonergy.com/learn/glossary/sei/", "mentions": [ "electrode", "graphite", "electrolyte" ] } }, { "id": "term:arrhenius", "type": "Term", "label": "Arrhenius law", "properties": { "id": "arrhenius", "name": "Arrhenius law", "section": "topic-aging", "definition": "The rule that a rate constant is proportional to exp(−Ea/RT), so a thermally activated reaction speeds up steeply with temperature. 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It is set by calendar aging, which runs fastest at high temperature and high state of charge.", "unit": "years", "related": [ "calendar-aging", "cycle-life", "end-of-life", "self-discharge", "calendar-life-test" ], "url": "https://lemonergy.com/learn/glossary/calendar-life/", "mentions": [ "state-of-charge" ] } }, { "id": "lesson:fundamentals/battery-aging/", "type": "Lesson", "label": "Lesson 4 · Battery aging", "properties": { "url": "https://lemonergy.com/learn/fundamentals/battery-aging/" } }, { "id": "visual:film", "type": "Visual", "label": "Diffusion-limited film growth", "properties": { "title": "Diffusion-limited film growth", "summary": "Four times the elapsed time gives twice the film thickness in this model.", "readout": "At four reference time units, thickness is 2× the reference thickness.", "formula": "δ / δ_ref = √[(t / t_ref) A]", "note": "Normalized analytical relation, not a capacity-loss or SOH prediction.", "software": { "status": "implemented", "label": "Implemented in battery-core", "body": "parabolic_film_thickness uses reference thickness × √(relative time × acceleration). Converting film thickness to capacity loss requires a calibrated relationship.", "href": "../fundamentals/battery-aging/" }, "html": "
Relative film growth
Relative film growthTime / reference time versus Thickness / reference thickness. Selected acceleration; Reference conditions. Interpretation follows the graphs.002448612816Time / reference timeThickness / referencethickness
Selected accelerationReference conditions (dashed)
" } }, { "id": "reference:edge-degradation", "type": "Reference", "label": "Lithium ion battery degradation: what you need to know", "properties": { "title": "Lithium ion battery degradation: what you need to know", "publisher": "Physical Chemistry Chemical Physics", "url": "https://doi.org/10.1039/D1CP00359C", "type": "Review article", "scope": "Degradation mechanisms, modes, operational effects and their interactions.", "year": 2021, "accessed": "2026-10-27" } } ] }