{ "node": { "id": "term:ultra-high-precision-coulometry", "type": "Term", "label": "Ultra-high-precision coulometry", "properties": { "id": "ultra-high-precision-coulometry", "name": "Ultra-high-precision coulometry", "abbr": "UHPC", "aka": [ "high-precision coulometry", "coulometry", "high-precision charger" ], "section": "topic-testing", "definition": "Measuring the charge into and out of a cell with chargers accurate to a few hundredths of a percent, at a temperature held within about ±0.1 °C, so that coulombic efficiency resolves to 0.01 % or better. Side-reaction rates then show within weeks, ranking electrolyte additives and materials long before cycle-life tests would finish.", "related": [ "coulombic-efficiency", "cycler", "electrolyte-additive", "cycle-life-test", "isothermal-calorimetry" ], "url": "https://lemonergy.com/learn/glossary/ultra-high-precision-coulometry/", "mentions": [ "electrolyte" ] } }, "edges": [ { "id": "edge:5362", "source": "term:ultra-high-precision-coulometry", "target": "topic:topic-testing", "type": "belongsTo", "properties": { "sourceFile": "terms.json" } }, { "id": "edge:5363", "source": "term:ultra-high-precision-coulometry", "target": "term:coulombic-efficiency", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:5364", "source": "term:ultra-high-precision-coulometry", "target": "term:cycler", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:5365", "source": "term:ultra-high-precision-coulometry", "target": "term:electrolyte-additive", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:5366", "source": "term:ultra-high-precision-coulometry", "target": "term:cycle-life-test", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:5367", "source": "term:ultra-high-precision-coulometry", "target": "term:isothermal-calorimetry", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:mentions/ultra-high-precision-coulometry/electrolyte", "source": "term:ultra-high-precision-coulometry", "target": "term:electrolyte", "type": "mentions", "properties": { "sourceFile": "terms.json", "method": "build_glossary.mention_index + mentions", "field": "definition", "meaning": "Text mention; not a causal claim" } }, { "id": "edge:5369", "source": "term:ultra-high-precision-coulometry", "target": "visual:efficiency", "type": "illustratedBy", "properties": { "sourceFile": "visual-pages.json" } } ], "neighbors": [ { "id": "topic:topic-testing", "type": "Topic", "label": "Testing methods", "properties": { "id": "topic-testing", "name": "Testing methods", "lede": "The measurements and test procedures that characterise a cell or pack, from capacity and pulse tests to abuse and environmental tests.", "context": "Record specimen, state, instrument, temperature and timing.", "example": "Resistance immediately after a current step can differ from a ten-second value because slower polarization contributes.", "lesson_url": "https://lemonergy.com/learn/fundamentals/capacity-and-c-rate/", "lesson_label": "Open capacity measurements" } }, { "id": "term:coulombic-efficiency", "type": "Term", "label": "Coulombic efficiency", "properties": { "id": "coulombic-efficiency", "name": "Coulombic efficiency", "abbr": "CE", "section": "topic-ratings", "definition": "Charge delivered on discharge divided by charge put in on the previous charge. A healthy lithium-ion cell exceeds 99.9 %; the missing fraction is lithium lost to side reactions, so CE is an early and sensitive aging signal.", "formula": "CE = Q_discharge / Q_charge", "unit": "%", "related": [ "energy-efficiency", "loss-of-lithium-inventory", "sei", "formation" ], "example": { "title": "Compare charge in and charge out", "text": "If a defined test charges 5.00 Ah and subsequently discharges 4.95 Ah over the chosen voltage window, its coulombic efficiency is 99%. 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Laboratory cyclers resolve microvolts; production formation cyclers handle thousands of cells at once.", "related": [ "testing", "capacity-test", "potentiostat", "formation", "cycler-file-formats" ], "url": "https://lemonergy.com/learn/glossary/cycler/", "mentions": [] } }, { "id": "term:electrolyte-additive", "type": "Term", "label": "Electrolyte additive", "properties": { "id": "electrolyte-additive", "name": "Electrolyte additive", "aka": [ "VC", "FEC" ], "section": "topic-electrolytes", "definition": "A compound added to the electrolyte at a few percent to improve one property — vinylene carbonate and fluoroethylene carbonate build a tougher SEI, others suppress gassing or overcharge. 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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": "term:isothermal-calorimetry", "type": "Term", "label": "Isothermal calorimetry", "properties": { "id": "isothermal-calorimetry", "name": "Isothermal calorimetry", "aka": [ "isothermal microcalorimetry", "IMC", "heat-flow calorimetry" ], "section": "topic-testing", "definition": "Holding a cell at constant temperature inside a calorimeter and measuring the heat it gives off, down to microwatts, while it cycles or rests. It separates reversible entropic heat from irreversible losses and reveals the parasitic heat of slow side reactions, a quick indicator of how long a cell will last.", "related": [ "heat-generation", "entropy-coefficient", "thermal-characterisation", "accelerating-rate-calorimetry", "ultra-high-precision-coulometry" ], "url": "https://lemonergy.com/learn/glossary/isothermal-calorimetry/", "mentions": [] } }, { "id": "term:electrolyte", "type": "Term", "label": "Electrolyte", "properties": { "id": "electrolyte", "name": "Electrolyte", "section": "topic-electrolytes", "definition": "The ion-conducting medium between the electrodes. In a liquid-electrolyte cell it fills the pores of both electrodes and the separator, so it is not a separate structural layer.", "related": [ "lithium-salt", "carbonate-solvent", "electrolyte-additive", "ionic-conductivity", "solid-electrolyte", "ionic-liquid-electrolyte" ], "lesson": "fundamentals/cell-architecture/#electrolyte", "example": { "title": "Ions and electrons", "text": "Electrolyte carries ions between electrodes; the external circuit carries electrons. The two paths serve different roles." }, "url": "https://lemonergy.com/learn/glossary/electrolyte/", "mentions": [ "separator" ] } }, { "id": "visual:efficiency", "type": "Visual", "label": "Charge efficiency versus energy efficiency", "properties": { "title": "Charge efficiency versus energy efficiency", "summary": "Returning most of the charge does not return the same fraction of energy.", "readout": "99% × 92% = 91.08% energy efficiency.", "formula": "η_energy = η_charge × V̄_discharge / V̄_charge", "note": "Matched cycle and measurement boundaries; auxiliary loads omitted.", "software": { "status": "reference", "label": "Reference concept", "body": "For matching cycle boundaries, energy efficiency = charge efficiency × mean discharge/charge voltage ratio. The core nominal-energy helper does not calculate cycle efficiency.", "href": "../fundamentals/capacity-and-c-rate/" }, "html": "
Recovered energy
Recovered energyEnergy put in (Wh) versus Energy recovered (Wh). Ideal 100%; Selected efficiencies. Interpretation follows the graphs.00252550507575100100Energy put in (Wh)Energy recovered (Wh)
Ideal 100%Selected efficiencies (dashed)
" } } ] }