{ "node": { "id": "term:calendar-life-test", "type": "Term", "label": "Calendar-life test", "properties": { "id": "calendar-life-test", "name": "Calendar-life test", "aka": [ "storage test" ], "section": "topic-testing", "definition": "Storing cells at a matrix of temperatures and states of charge, typically 25–60 °C and 30–100 % SOC, with periodic reference tests, to fit the calendar-aging model. Months of data at high temperature are extrapolated to years at ambient through the Arrhenius law.", "related": [ "calendar-aging", "calendar-life", "arrhenius", "storage-soc", "accelerated-aging" ], "url": "https://lemonergy.com/learn/glossary/calendar-life-test/", "mentions": [ "state-of-charge" ] } }, "edges": [ { "id": "edge:3929", "source": "term:calendar-life-test", "target": "topic:topic-testing", "type": "belongsTo", "properties": { "sourceFile": "terms.json" } }, { "id": "edge:3930", "source": "term:calendar-life-test", "target": "term:calendar-aging", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:3931", "source": "term:calendar-life-test", "target": "term:calendar-life", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:3932", "source": "term:calendar-life-test", "target": "term:arrhenius", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:3933", "source": "term:calendar-life-test", "target": "term:storage-soc", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:3934", "source": "term:calendar-life-test", "target": "term:accelerated-aging", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:mentions/calendar-life-test/state-of-charge", "source": "term:calendar-life-test", "target": "term:state-of-charge", "type": "mentions", "properties": { "sourceFile": "terms.json", "method": "build_glossary.mention_index + mentions", "field": "definition", "meaning": "Text mention; not a causal claim" } }, { "id": "edge:3936", "source": "term:calendar-life-test", "target": "visual:film", "type": "illustratedBy", "properties": { "sourceFile": "visual-pages.json" } }, { "id": "edge:3937", "source": "term:calendar-life-test", "target": "reference:inl-ev-tests", "type": "cites", "properties": { "sourceFile": "wiki-references.json", "scope": "direct technical reference" } } ], "neighbors": [ { "id": "topic:topic-testing", "type": "Topic", "label": "Testing methods", "properties": { "id": "topic-testing", "name": "Testing methods", "lede": "The measurements and test procedures that characterise a cell or pack, from capacity and pulse tests to abuse and environmental tests.", "context": "Record specimen, state, instrument, temperature and timing.", "example": "Resistance immediately after a current step can differ from a ten-second value because slower polarization contributes.", "lesson_url": "https://lemonergy.com/learn/fundamentals/capacity-and-c-rate/", "lesson_label": "Open capacity measurements" } }, { "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. It is driven mainly by side reactions such as SEI growth and accelerates with temperature.", "related": [ "cycle-aging", "sei", "arrhenius", "square-root-of-time", "calendar-life" ], "lesson": "fundamentals/battery-aging/#whole-cell", "url": "https://lemonergy.com/learn/glossary/calendar-aging/", "mentions": [] } }, { "id": "term:calendar-life", "type": "Term", "label": "Calendar life", "properties": { "id": "calendar-life", "name": "Calendar life", "aka": [ "shelf life" ], "section": "topic-ratings", "definition": "How long a cell lasts in years, regardless of cycling, before it reaches its end-of-life criterion. 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": "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. Near room temperature many degradation reactions roughly double their rate for every +10 °C.", "formula": "k = A·exp(−Eₐ/RT)", "related": [ "activation-energy", "calendar-aging", "operating-temperature", "accelerated-aging", "celsius-kelvin" ], "lesson": "fundamentals/battery-aging/#arrhenius", "example": { "title": "Compare reaction-rate factors", "text": "For an illustrative activation energy of 40 kJ/mol, increasing temperature from 25 °C to 35 °C multiplies the modeled rate by about 1.69. Convert both temperatures to kelvin before evaluating the exponential." }, "notes": [ "A reaction-rate factor alone is not a prediction of battery lifetime." ], "url": "https://lemonergy.com/learn/glossary/arrhenius/", "mentions": [] } }, { "id": "term:storage-soc", "type": "Term", "label": "Storage state of charge", "properties": { "id": "storage-soc", "name": "Storage state of charge", "section": "topic-aging", "definition": "The state of charge at which a cell is kept when idle. Calendar aging rises with SOC because the negative electrode sits at a lower, more reactive potential, so cells are shipped and stored at 30–50 % rather than full.", "unit": "%", "related": [ "calendar-aging", "state-of-charge", "shipping-soc" ], "lesson": "fundamentals/battery-aging/#storage-soc", "url": "https://lemonergy.com/learn/glossary/storage-soc/", "mentions": [ "electrode", "negative-electrode" ] } }, { "id": "term:accelerated-aging", "type": "Term", "label": "Accelerated aging test", "properties": { "id": "accelerated-aging", "name": "Accelerated aging test", "section": "topic-testing", "definition": "Aging cells faster than in service — at higher temperature, higher SOC or higher rate — and extrapolating to real conditions with a model such as Arrhenius. The extrapolation only holds if acceleration does not change which mechanism dominates.", "related": [ "arrhenius", "calendar-aging", "cycle-aging", "aging-model", "reference-performance-test" ], "url": "https://lemonergy.com/learn/glossary/accelerated-aging/", "mentions": [ "state-of-charge" ] } }, { "id": "term:state-of-charge", "type": "Term", "label": "State of charge", "properties": { "id": "state-of-charge", "name": "State of charge", "abbr": "SOC", "section": "topic-state", "definition": "How full a cell is, as a fraction of its available capacity. State of charge, like temperature, affects how fast a stored cell ages.", "unit": "%", "related": [ "depth-of-discharge", "ocv-soc-curve", "coulomb-counting", "state-of-health", "bms" ], "lesson": "fundamentals/battery-aging/#storage-soc", "example": { "title": "Interpret a charge inventory", "text": "If available capacity is 5 Ah and 3 Ah remains by the chosen estimator, SOC is 60%. A different estimate of available capacity changes this percentage, so compare SOC values only with the capacity convention recorded." }, "url": "https://lemonergy.com/learn/glossary/state-of-charge/", "mentions": [ "usable-capacity" ] } }, { "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:inl-ev-tests", "type": "Reference", "label": "Battery Test Manual For Electric Vehicles, Revision 3", "properties": { "title": "Battery Test Manual For Electric Vehicles, Revision 3", "publisher": "Idaho National Laboratory", "url": "https://inldigitallibrary.inl.gov/sites/sti/sti/6492291.pdf", "type": "Test manual", "scope": "Performance characterization, pulse resistance/power, life testing and reference performance tests; historical 2015 edition.", "year": 2015, "authors": [ "Jon P. Christopherson" ], "accessed": "2026-10-27" } } ] }