{ "node": { "id": "term:state-of-resistance", "type": "Term", "label": "State of resistance", "properties": { "id": "state-of-resistance", "name": "State of resistance", "abbr": "SoR", "aka": [ "SOH-R", "resistance state of health" ], "section": "topic-state", "definition": "The internal resistance of a cell compared with its value when new: the power half of state of health. It is quoted as a ratio or a percentage increase; a doubling of resistance is a common end-of-life criterion where power matters more than capacity, as in hybrids.", "formula": "SoR = R_now / R_BOL", "related": [ "state-of-health", "impedance-rise", "internal-resistance", "state-of-power", "state-of-capacity", "dcir" ], "example": { "title": "Compare resistance under the same test", "text": "If resistance measured under matching conditions increases from 10 mΩ at beginning of life to 15 mΩ, SoR = 1.5, or 150% of the initial resistance. It is not a remaining-capacity percentage." }, "url": "https://lemonergy.com/learn/glossary/state-of-resistance/", "mentions": [] } }, "edges": [ { "id": "edge:6502", "source": "term:state-of-resistance", "target": "topic:topic-state", "type": "belongsTo", "properties": { "sourceFile": "terms.json" } }, { "id": "edge:6503", "source": "term:state-of-resistance", "target": "term:state-of-health", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:6504", "source": "term:state-of-resistance", "target": "term:impedance-rise", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:6505", "source": "term:state-of-resistance", "target": "term:internal-resistance", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:6506", "source": "term:state-of-resistance", "target": "term:state-of-power", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:6507", "source": "term:state-of-resistance", "target": "term:state-of-capacity", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:6508", "source": "term:state-of-resistance", "target": "term:dcir", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:6509", "source": "term:state-of-resistance", "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: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:internal-resistance", "type": "Term", "label": "Internal resistance", "properties": { "id": "internal-resistance", "name": "Internal resistance", "abbr": "IR", "aka": [ "DC resistance", "DCIR" ], "section": "topic-units", "definition": "The resistance a cell presents to current, from its foils, electrolyte, interfaces and the reactions themselves. It converts part of the delivered energy into heat, sets the voltage drop under load, and rises as the cell ages; a large automotive cell has about a milliohm, a small cylindrical cell tens.", "unit": "mΩ", "related": [ "ohms-law", "ir-drop", "impedance-rise", "dcir", "area-specific-resistance", "resistance-capacity-product" ], "lesson": "fundamentals/battery-basics/#datasheet", "url": "https://lemonergy.com/learn/glossary/internal-resistance/", "mentions": [ "electrolyte", "cylindrical-cell" ] } }, { "id": "term:state-of-power", "type": "Term", "label": "State of power", "properties": { "id": "state-of-power", "name": "State of power", "abbr": "SOP", "section": "topic-state", "definition": "The maximum charge or discharge power a battery can deliver for the next few seconds without breaking a voltage, current or temperature limit. The BMS recomputes it continuously from SOC, temperature and resistance and sends it to the motor controller.", "unit": "W", "related": [ "power", "state-of-charge", "continuous-current", "derating", "bms", "state-of-function" ], "url": "https://lemonergy.com/learn/glossary/state-of-power/", "mentions": [] } }, { "id": "term:state-of-capacity", "type": "Term", "label": "State of capacity", "properties": { "id": "state-of-capacity", "name": "State of capacity", "abbr": "SoQ", "aka": [ "SOH-C", "capacity retention" ], "section": "topic-state", "definition": "The charge a cell or pack can still hold, as a percentage of its rated or beginning-of-life capacity: the capacity half of state of health. A cell measured at 82 Ah against a 100 Ah rating has an SoQ of 82 %, and the usual 80 % end-of-life convention is written against it.", "formula": "SoQ = Q_now / Q_rated × 100 %", "unit": "%", "related": [ "state-of-health", "capacity-fade", "state-of-resistance", "nominal-capacity", "end-of-life" ], "example": { "title": "Compare current and reference capacity", "text": "If present available capacity is 45 Ah and the selected rated reference is 50 Ah, SoQ is 90%. The reference temperature, current and voltage window belong with the number." }, "url": "https://lemonergy.com/learn/glossary/state-of-capacity/", "mentions": [] } }, { "id": "term:dcir", "type": "Term", "label": "DC internal resistance", "properties": { "id": "dcir", "name": "DC internal resistance", "abbr": "DCIR", "aka": [ "DC-IR", "pulse resistance" ], "section": "topic-testing", "definition": "Internal resistance measured from the voltage change during a current pulse of defined length, usually 10 s or 18 s. It is larger than the AC value because it includes charge-transfer and some diffusion, and it depends on SOC, temperature and pulse duration.", "unit": "mΩ", "related": [ "internal-resistance", "acir", "hppc", "impedance-rise" ], "url": "https://lemonergy.com/learn/glossary/dcir/", "mentions": [ "state-of-charge", "diffusion" ] } }, { "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)
" } } ] }