{ "node": { "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" ] } }, "edges": [ { "id": "edge:usedIn/term:state-of-health/workflow:native-battery-capacity-health", "source": "term:state-of-health", "target": "workflow:native-battery-capacity-health", "type": "usedIn", "properties": { "sourceFile": "wiki-blocks.json" } }, { "id": "edge:usedIn/term:state-of-health/workflow:native-battery-resistance-health", "source": "term:state-of-health", "target": "workflow:native-battery-resistance-health", "type": "usedIn", "properties": { "sourceFile": "wiki-blocks.json" } }, { "id": "edge:belongsTo/term:state-of-health/topic:topic-state", "source": "term:state-of-health", "target": "topic:topic-state", "type": "belongsTo", "properties": { "sourceFile": "terms.json" } }, { "id": "edge:relatedTo/term:state-of-health/term:capacity-fade", "source": "term:state-of-health", "target": "term:capacity-fade", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:relatedTo/term:state-of-health/term:impedance-rise", "source": "term:state-of-health", "target": "term:impedance-rise", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:relatedTo/term:state-of-health/term:end-of-life", "source": "term:state-of-health", "target": "term:end-of-life", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:relatedTo/term:state-of-health/term:remaining-useful-life", "source": "term:state-of-health", "target": "term:remaining-useful-life", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:relatedTo/term:state-of-health/term:state-of-charge", "source": "term:state-of-health", "target": "term:state-of-charge", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:relatedTo/term:state-of-health/term:state-of-certified-energy", "source": "term:state-of-health", "target": "term:state-of-certified-energy", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:mentions/state-of-health/nominal-capacity", "source": "term:state-of-health", "target": "term:nominal-capacity", "type": "mentions", "properties": { "sourceFile": "terms.json", "method": "build_glossary.mention_index + mentions", "field": "definition", "meaning": "Text mention; not a causal claim" } }, { "id": "edge:explainedIn/term:state-of-health/lesson:fundamentals/capacity-and-c-rate/", "source": "term:state-of-health", "target": "lesson:fundamentals/capacity-and-c-rate/", "type": "explainedIn", "properties": { "sourceFile": "terms.json", "url": "https://lemonergy.com/learn/fundamentals/capacity-and-c-rate/#real-cells" } }, { "id": "edge:illustratedBy/term:state-of-health/visual:health", "source": "term:state-of-health", "target": "visual:health", "type": "illustratedBy", "properties": { "sourceFile": "visual-pages.json" } } ], "neighbors": [ { "id": "workflow:native-battery-capacity-health", "type": "Workflow", "label": "Capacity health index worked example", "properties": { "id": "native-battery-capacity-health", "title": "Capacity health index worked example", "kind": "studio", "summary": "Endpoint-normalized health index with raw value and out-of-reference flag.", "steps": [ "Review the block inputs, units and model limits.", "Open the Studio example and run its bundled model.", "Compare the output channels with the numerical checks; change one input and run again." ], "example": "Use the defaults below with Measured capacity (Ah) = 1.8 Ah. At 0 s, Clipped health index is 0.5 1 (fraction). Additional checks are listed below.", "observe": "Inspect the outputs and numerical checks on the block reference page.", "limits": "This endpoint-normalized index is not the same quantity as capacity retention. The endpoint choice determines its interpretation. The example verifies numerical behavior for synthetic parameters. Cell characterization and validation for an intended use are separate tasks.", "url": "https://design.lemonergy.com/cosim.html?example=block-battery-capacity-health", "label": "Open Studio example", "evidence": [ "docs/glossary/native-block-verification.json" ] } }, { "id": "workflow:native-battery-resistance-health", "type": "Workflow", "label": "Resistance health index worked example", "properties": { "id": "native-battery-resistance-health", "title": "Resistance health index worked example", "kind": "studio", "summary": "Endpoint-normalized health index with raw value and out-of-reference flag.", "steps": [ "Review the block inputs, units and model limits.", "Open the Studio example and run its bundled model.", "Compare the output channels with the numerical checks; change one input and run again." ], "example": "Use the defaults below with Measured resistance (ohm) = 0.075 1. At 0 s, Clipped health index is 0.5 1 (fraction). Additional checks are listed below.", "observe": "Inspect the outputs and numerical checks on the block reference page.", "limits": "This endpoint-normalized index is not the same quantity as capacity retention. The endpoint choice determines its interpretation. The example verifies numerical behavior for synthetic parameters. Cell characterization and validation for an intended use are separate tasks.", "url": "https://design.lemonergy.com/cosim.html?example=block-battery-resistance-health", "label": "Open Studio example", "evidence": [ "docs/glossary/native-block-verification.json" ] } }, { "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: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", "capacity-retention" ], "lesson": "fundamentals/battery-aging/#chain", "url": "https://lemonergy.com/learn/glossary/capacity-fade/", "mentions": [ "active-material", "sei" ] } }, { "id": "term:impedance-rise", "type": "Term", "label": "Impedance rise", "properties": { "id": "impedance-rise", "name": "Impedance rise", "aka": [ "resistance growth", "power fade" ], "section": "topic-aging", "definition": "An increase in a cell’s internal resistance as it ages. It costs voltage under load and therefore power, even while the stored charge is still there.", "related": [ "internal-resistance", "sei", "cei", "state-of-power", "state-of-health" ], "lesson": "fundamentals/battery-aging/#crystals", "url": "https://lemonergy.com/learn/glossary/impedance-rise/", "mentions": [ "closed-circuit-voltage" ] } }, { "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: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": [] } }, { "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": "term:state-of-certified-energy", "type": "Term", "label": "State of certified energy", "properties": { "id": "state-of-certified-energy", "name": "State of certified energy", "abbr": "SOCE", "section": "topic-state", "definition": "A vehicle battery’s present usable energy, read from the on-board monitor, as a percentage of the usable energy certified when new. UN GTR 22 requires at least 80 % after 5 years or 100 000 km and 70 % after 8 years or 160 000 km; Euro 7 raises the second figure to 72 % for cars.", "formula": "SOCE = E_usable,now / E_usable,certified × 100 %", "unit": "%", "related": [ "state-of-health", "state-of-energy", "warranty", "usable-capacity", "electric-vehicle" ], "example": { "title": "Compare retained and certified usable energy", "text": "A battery delivering 54 kWh in the relevant assessment against a 60 kWh certified reference has SOCE = 90%. Keep the required assessment conditions and reference definition consistent." }, "url": "https://lemonergy.com/learn/glossary/state-of-certified-energy/", "mentions": [] } }, { "id": "term:nominal-capacity", "type": "Term", "label": "Nominal capacity", "properties": { "id": "nominal-capacity", "name": "Nominal capacity", "aka": [ "rated capacity" ], "section": "topic-ratings", "definition": "The charge a cell is rated to deliver under specified test conditions — current, temperature, rest and voltage limits — usually in ampere-hours.", "unit": "Ah", "related": [ "ampere-hour", "c-rate", "capacity-test", "usable-capacity", "state-of-health" ], "lesson": "fundamentals/capacity-and-c-rate/#nominal-capacity", "url": "https://lemonergy.com/learn/glossary/nominal-capacity/", "mentions": [] } }, { "id": "lesson:fundamentals/capacity-and-c-rate/", "type": "Lesson", "label": "Lesson 2 · Capacity and C-rate", "properties": { "url": "https://lemonergy.com/learn/fundamentals/capacity-and-c-rate/" } }, { "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)
" } } ] }