{ "node": { "id": "term:cycle-aging", "type": "Term", "label": "Cycle aging", "properties": { "id": "cycle-aging", "name": "Cycle aging", "section": "topic-aging", "definition": "Degradation caused by charging and discharging: mechanical strain in the particles, fresh SEI on cracked surfaces and, at high rate or low temperature, lithium plating. 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New surfaces consume electrolyte to form fresh SEI, and fragments that lose contact no longer store lithium.", "related": [ "cycle-aging", "loss-of-active-material", "silicon-anode", "single-crystal", "depth-of-discharge" ], "lesson": "fundamentals/battery-aging/#cracking", "url": "https://lemonergy.com/learn/glossary/particle-cracking/", "mentions": [ "electrolyte", "sei" ] } }, { "id": "term:lithium-plating", "type": "Term", "label": "Lithium plating", "properties": { "id": "lithium-plating", "name": "Lithium plating", "section": "topic-aging", "definition": "Lithium metal depositing on the negative-electrode surface instead of intercalating into it. It is promoted by charging at low temperature or high current.", "related": [ "dendrite", "fast-charging", "intercalation", "np-ratio", "dead-lithium", "electrodeposition" ], "lesson": "fundamentals/battery-aging/#plating", "url": "https://lemonergy.com/learn/glossary/lithium-plating/", "mentions": [] } }, { "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: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:sei", "type": "Term", "label": "Solid–electrolyte interphase", "properties": { "id": "sei", "name": "Solid–electrolyte interphase", "abbr": "SEI", "section": "topic-aging", "definition": "A film of electrolyte reaction products on the negative-electrode particles — graphite, and also silicon or lithium metal. It protects the electrode from further reaction but grows slowly for the whole life of the cell, consuming cyclable lithium.", "related": [ "passivation", "formation", "calendar-aging", "loss-of-lithium-inventory", "cei" ], "lesson": "fundamentals/battery-aging/#sei", "url": "https://lemonergy.com/learn/glossary/sei/", "mentions": [ "electrode", "graphite", "electrolyte" ] } }, { "id": "term:c-rate", "type": "Term", "label": "C-rate", "properties": { "id": "c-rate", "name": "C-rate", "section": "topic-ratings", "definition": "Current divided by nominal capacity, in reciprocal hours. 1C on a 20 Ah cell is 20 A; 2C is 40 A. C-rate lets you compare loads on cells of different sizes.", "formula": "C-rate = I / Q_nominal", "unit": "h⁻¹", "related": [ "nominal-capacity", "ideal-duration", "current", "e-rate", "fast-charging" ], "lesson": "fundamentals/capacity-and-c-rate/#c-rate", "example": { "title": "Convert a rating into amperes", "text": "For a 5 Ah cell, 0.5C means 2.5 A, 1C means 5 A and 2C means 10 A. Dividing 2.5 A by 5 Ah returns 0.5 h⁻¹, conventionally written 0.5C." }, "url": "https://lemonergy.com/learn/glossary/c-rate/", "mentions": [] } }, { "id": "term:energy-throughput", "type": "Term", "label": "Energy throughput", "properties": { "id": "energy-throughput", "name": "Energy throughput", "aka": [ "lifetime throughput", "MWh throughput", "charge throughput", "Ah throughput" ], "section": "topic-ratings", "definition": "The total energy a battery has delivered, or charged and discharged, over its life, counted in kWh or MWh. Discharged energy divided by usable energy gives equivalent full cycles. Stationary-storage and electric-bus warranties often set a throughput limit alongside years, because aging tracks the energy cycled as well as time.", "unit": "kWh, MWh", "related": [ "equivalent-full-cycle", "warranty", "cycle-life", "stationary-storage", "levelized-cost-of-storage", "electric-bus" ], "url": "https://lemonergy.com/learn/glossary/energy-throughput/", "mentions": [ "kilowatt-hour" ] } }, { "id": "lesson:fundamentals/battery-aging/", "type": "Lesson", "label": "Lesson 4 · Battery aging", "properties": { "url": "https://lemonergy.com/learn/fundamentals/battery-aging/" } }, { "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)
" } }, { "id": "reference:edge-degradation", "type": "Reference", "label": "Lithium ion battery degradation: what you need to know", "properties": { "title": "Lithium ion battery degradation: what you need to know", "publisher": "Physical Chemistry Chemical Physics", "url": "https://doi.org/10.1039/D1CP00359C", "type": "Review article", "scope": "Degradation mechanisms, modes, operational effects and their interactions.", "year": 2021, "accessed": "2026-10-27" } } ] }