{ "node": { "id": "term:remaining-useful-life", "type": "Term", "label": "Remaining useful life", "properties": { "id": "remaining-useful-life", "name": "Remaining useful life", "abbr": "RUL", "section": "topic-state", "definition": "A prediction of how many cycles, or how much time, a battery has left before reaching end of life. It is estimated from the trend of state of health, and is uncertain near a knee point where fade accelerates.", "related": [ "state-of-health", "end-of-life", "knee-point", "cycle-life" ], "url": "https://lemonergy.com/learn/glossary/remaining-useful-life/", "mentions": [] } }, "edges": [ { "id": "edge:1273", "source": "term:remaining-useful-life", "target": "topic:topic-state", "type": "belongsTo", "properties": { "sourceFile": "terms.json" } }, { "id": "edge:1274", "source": "term:remaining-useful-life", "target": "term:state-of-health", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:1275", "source": "term:remaining-useful-life", "target": "term:end-of-life", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:1276", "source": "term:remaining-useful-life", "target": "term:knee-point", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:1277", "source": "term:remaining-useful-life", "target": "term:cycle-life", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:1278", "source": "term:remaining-useful-life", "target": "visual:health", "type": "illustratedBy", "properties": { "sourceFile": "visual-pages.json" } } ], "neighbors": [ { "id": "topic:topic-state", "type": "Topic", "label": "State estimation", "properties": { "id": "topic-state", "name": "State estimation", "lede": "The quantities a battery management system estimates but cannot measure directly.", "context": "Distinguish internal states from noisy measurement estimates.", "example": "Current-sensor bias accumulates in coulomb counting. Exact model SOC does not establish real estimator accuracy.", "lesson_url": "https://lemonergy.com/learn/fundamentals/capacity-and-c-rate/", "lesson_label": "Open charge balance" } }, { "id": "term:state-of-health", "type": "Term", "label": "State of health", "properties": { "id": "state-of-health", "name": "State of health", "abbr": "SOH", "section": "topic-state", "definition": "A summary of how far a cell has aged, often expressed through remaining capacity or increased resistance compared with when it was new. By convention a cell has reached end of life at 80 % of its rated capacity.", "unit": "%", "related": [ "capacity-fade", "impedance-rise", "end-of-life", "remaining-useful-life", "state-of-charge", "state-of-certified-energy" ], "lesson": "fundamentals/capacity-and-c-rate/#real-cells", "url": "https://lemonergy.com/learn/glossary/state-of-health/", "mentions": [ "nominal-capacity" ] } }, { "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:knee-point", "type": "Term", "label": "Knee point", "properties": { "id": "knee-point", "name": "Knee point", "aka": [ "rollover", "sudden death" ], "section": "topic-aging", "definition": "The point in a capacity-versus-cycles curve where slow, roughly linear fade turns into rapid loss. It usually marks the onset of lithium plating or electrolyte dry-out, and a cell past its knee is unpredictable and should be retired.", "related": [ "capacity-fade", "lithium-plating", "electrolyte-dry-out", "remaining-useful-life", "end-of-life" ], "url": "https://lemonergy.com/learn/glossary/knee-point/", "mentions": [ "electrolyte" ] } }, { "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": [] } }, { "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)
" } } ] }