{ "node": { "id": "term:cycle-life", "type": "Term", "label": "Cycle life", "properties": { "id": "cycle-life", "name": "Cycle life", "section": "topic-ratings", "definition": "The number of full charge–discharge cycles a cell completes before its capacity falls to a stated fraction, usually 80 %, of its initial value under defined conditions. LFP cells reach several thousand cycles; high-energy NMC fewer.", "unit": "cycles", "related": [ "end-of-life", "capacity-fade", "depth-of-discharge", "calendar-life", "equivalent-full-cycle", "cycle-life-test" ], "url": "https://lemonergy.com/learn/glossary/cycle-life/", "mentions": [] } }, "edges": [ { "id": "edge:1006", "source": "term:cycle-life", "target": "topic:topic-ratings", "type": "belongsTo", "properties": { "sourceFile": "terms.json" } }, { "id": "edge:1007", "source": "term:cycle-life", "target": "term:end-of-life", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:1008", "source": "term:cycle-life", "target": "term:capacity-fade", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:1009", "source": "term:cycle-life", "target": "term:depth-of-discharge", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:1010", "source": "term:cycle-life", "target": "term:calendar-life", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:1011", "source": "term:cycle-life", "target": "term:equivalent-full-cycle", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:1012", "source": "term:cycle-life", "target": "term:cycle-life-test", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:1013", "source": "term:cycle-life", "target": "visual:health", "type": "illustratedBy", "properties": { "sourceFile": "visual-pages.json" } } ], "neighbors": [ { "id": "topic:topic-ratings", "type": "Topic", "label": "Capacity, energy, power and ratings", "properties": { "id": "topic-ratings", "name": "Capacity, energy, power and ratings", "lede": "The numbers that size a cell and let two cells be compared.", "context": "Separate nameplate ratings from test results.", "example": "5 Ah at 3.6 V gives 18 Wh nominally. Integrated measured terminal power may give a different result.", "lesson_url": "https://lemonergy.com/learn/fundamentals/capacity-and-c-rate/", "lesson_label": "Open capacity and C-rate" } }, { "id": "term:end-of-life", "type": "Term", "label": "End of life", "properties": { "id": "end-of-life", "name": "End of life", "abbr": "EOL", "section": "topic-state", "definition": "The point at which a cell no longer meets its application’s requirement, conventionally 80 % of initial capacity or a doubling of resistance. It is a definition for warranties and tests, not a point where the cell stops working.", "related": [ "state-of-health", "beginning-of-life", "cycle-life", "second-life", "knee-point" ], "url": "https://lemonergy.com/learn/glossary/end-of-life/", "mentions": [] } }, { "id": "term:capacity-fade", "type": "Term", "label": "Capacity fade", "properties": { "id": "capacity-fade", "name": "Capacity fade", "section": "topic-aging", "definition": "The loss of charge a cell can store and deliver, for example through lithium locked into the SEI or active material that has cracked out of service.", "related": [ "loss-of-lithium-inventory", "loss-of-active-material", "state-of-health", "knee-point" ], "lesson": "fundamentals/battery-aging/#chain", "url": "https://lemonergy.com/learn/glossary/capacity-fade/", "mentions": [ "active-material", "sei" ] } }, { "id": "term:depth-of-discharge", "type": "Term", "label": "Depth of discharge", "properties": { "id": "depth-of-discharge", "name": "Depth of discharge", "abbr": "DOD", "section": "topic-state", "definition": "How much of a cell’s capacity is used in a cycle. Deep cycles cause more mechanical stress in the active materials than shallow ones.", "unit": "%", "related": [ "state-of-charge", "cycle-life", "particle-cracking", "usable-capacity" ], "lesson": "fundamentals/battery-aging/#cracking", "url": "https://lemonergy.com/learn/glossary/depth-of-discharge/", "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:equivalent-full-cycle", "type": "Term", "label": "Equivalent full cycle", "properties": { "id": "equivalent-full-cycle", "name": "Equivalent full cycle", "abbr": "EFC", "section": "topic-ratings", "definition": "Total charge throughput divided by nominal capacity, so that many shallow cycles count as the equivalent number of full ones. It lets cycle life be compared across different duty cycles.", "formula": "EFC = ΣQ_throughput / (2·Q_nominal)", "related": [ "cycle-life", "depth-of-discharge", "cycle" ], "example": { "title": "Count partial throughput", "text": "For a 5 Ah reference capacity, 20 Ah of total absolute charge-plus-discharge throughput corresponds to 20/(2 × 5) = 2 EFC. If counting discharge throughput only, use its matching convention without the factor of two." }, "url": "https://lemonergy.com/learn/glossary/equivalent-full-cycle/", "mentions": [ "nominal-capacity", "energy-throughput" ] } }, { "id": "term:cycle-life-test", "type": "Term", "label": "Cycle-life test", "properties": { "id": "cycle-life-test", "name": "Cycle-life test", "aka": [ "cycling test", "endurance test" ], "section": "topic-testing", "definition": "Repeating a defined charge and discharge cycle at fixed temperature until capacity reaches the end-of-life criterion, with a reference performance test every few hundred cycles. Conditions — rate, depth of discharge, voltage window, temperature — decide the result, so they are always quoted with it.", "related": [ "cycle-life", "reference-performance-test", "accelerated-aging", "depth-of-discharge", "iec-62660" ], "url": "https://lemonergy.com/learn/glossary/cycle-life-test/", "mentions": [ "voltage-window" ] } }, { "id": "visual:health", "type": "Visual", "label": "Capacity loss and resistance growth", "properties": { "title": "Capacity loss and resistance growth", "summary": "Energy capability and power capability can degrade differently.", "readout": "At the illustrated endpoint: 80% initial capacity and 140% initial resistance.", "formula": "Capacity ratio = Q_now/Q_initial; resistance ratio = R_now/R_initial", "note": "Chosen qualitative trends. The exposure axis is not predicted cycles or years.", "software": { "status": "reference", "label": "Reference concept", "body": "battery-core supplies individual aging relationships, not a calibrated SOH or remaining-life estimator. The selected trends are illustrations and do not predict cycles or years.", "href": "../fundamentals/battery-aging/" }, "html": "
Chosen degradation trends
Chosen degradation trendsRelative life exposure versus Relative to beginning of life (%). Capacity retained; Resistance. Interpretation follows the graphs.50087.50.251250.51630.752001Relative life exposureRelative to beginning oflife (%)
Capacity retainedResistance (dashed)
" } } ] }