{ "node": { "id": "term:volt", "type": "Term", "label": "Volt", "properties": { "id": "volt", "name": "Volt", "abbr": "V", "section": "topic-units", "definition": "The SI unit of electric potential difference: one joule of energy per coulomb of charge. A lithium-ion cell sits around 3–4 V; packs reach hundreds of volts by putting cells in series.", "unit": "V", "related": [ "voltage", "nominal-voltage", "series-parallel" ], "url": "https://lemonergy.com/learn/glossary/volt/", "mentions": [ "coulomb", "joule" ] } }, "edges": [ { "id": "edge:156", "source": "term:volt", "target": "workflow:ohm-circuit", "type": "usedIn", "properties": { "sourceFile": "wiki-blocks.json" } }, { "id": "edge:183", "source": "term:volt", "target": "topic:topic-units", "type": "belongsTo", "properties": { "sourceFile": "terms.json" } }, { "id": "edge:184", "source": "term:volt", "target": "term:voltage", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:185", "source": "term:volt", "target": "term:nominal-voltage", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:186", "source": "term:volt", "target": "term:series-parallel", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:mentions/volt/coulomb", "source": "term:volt", "target": "term:coulomb", "type": "mentions", "properties": { "sourceFile": "terms.json", "method": "build_glossary.mention_index + mentions", "field": "definition", "meaning": "Text mention; not a causal claim" } }, { "id": "edge:mentions/volt/joule", "source": "term:volt", "target": "term:joule", "type": "mentions", "properties": { "sourceFile": "terms.json", "method": "build_glossary.mention_index + mentions", "field": "definition", "meaning": "Text mention; not a causal claim" } }, { "id": "edge:189", "source": "term:volt", "target": "visual:voltage", "type": "illustratedBy", "properties": { "sourceFile": "visual-pages.json" } }, { "id": "edge:190", "source": "term:volt", "target": "reference:bipm-si", "type": "cites", "properties": { "sourceFile": "wiki-references.json", "scope": "direct technical reference" } } ], "neighbors": [ { "id": "workflow:ohm-circuit", "type": "Workflow", "label": "Relate current and voltage", "properties": { "id": "ohm-circuit", "title": "Relate current and voltage", "kind": "studio", "summary": "Conserving components solve constitutive relations and node balance.", "steps": [ "Inspect source and resistor in the RC example.", "Compare branch current with resistor voltage." ], "example": "A 1 V drop across 2 Ω implies 0.5 A.", "observe": "Topology sets individual element voltages.", "limits": "The RC example includes a capacitor: transient current varies and source voltage is not always resistor voltage.", "url": "https://design.lemonergy.com/cosim.html?example=physical-rc", "label": "Open the electrical circuit", "evidence": [ "js/physical-network.js", "js/studio-examples.js" ] } }, { "id": "topic:topic-units", "type": "Topic", "label": "Units and electrical basics", "properties": { "id": "topic-units", "name": "Units and electrical basics", "lede": "The quantities every datasheet is written in, and how they relate.", "context": "Use consistent units and cell/pack basis.", "example": "10 A for 30 min transfers 5 Ah. At constant 3.6 V this is 18 Wh; varying voltage requires integration.", "lesson_url": "https://lemonergy.com/learn/fundamentals/capacity-and-c-rate/", "lesson_label": "Open capacity and C-rate" } }, { "id": "term:voltage", "type": "Term", "label": "Voltage", "properties": { "id": "voltage", "name": "Voltage", "aka": [ "terminal voltage" ], "section": "topic-units", "definition": "The potential difference between a cell’s two terminals. It comes from the chemical difference between the electrodes, moves with state of charge, and sags under load because of internal resistance.", "unit": "V", "related": [ "open-circuit-voltage", "nominal-voltage", "internal-resistance", "ir-drop" ], "lesson": "fundamentals/cell-anatomy/#voltage", "url": "https://lemonergy.com/learn/glossary/voltage/", "mentions": [ "state-of-charge" ] } }, { "id": "term:nominal-voltage", "type": "Term", "label": "Nominal voltage", "properties": { "id": "nominal-voltage", "name": "Nominal voltage", "section": "topic-ratings", "definition": "A representative average voltage of a cell over a full discharge, such as 3.6–3.7 V for an oxide/graphite cell or about 3.2 V for LFP/graphite. Multiplied by capacity, it gives nominal energy.", "unit": "V", "related": [ "nominal-energy", "open-circuit-voltage", "voltage-window", "lfp" ], "lesson": "fundamentals/capacity-and-c-rate/#energy", "url": "https://lemonergy.com/learn/glossary/nominal-voltage/", "mentions": [ "graphite" ] } }, { "id": "term:series-parallel", "type": "Term", "label": "Series and parallel connection", "properties": { "id": "series-parallel", "name": "Series and parallel connection", "aka": [ "xSyP" ], "section": "topic-pack", "definition": "Cells in series add their voltages; cells in parallel add their capacities and share current. A pack is described as, for example, 96s4p: 96 groups in series, each of 4 cells in parallel. Series strings need balancing; parallel groups self-balance through their shared terminals.", "formula": "V = n_s·V_cell, Q = n_p·Q_cell", "related": [ "module", "cell-balancing", "pack-voltage", "volt", "fuse" ], "lesson": "fundamentals/battery-basics/#cell-module-pack", "example": { "title": "Assemble an ideal 4s2p pack", "text": "Eight identical 3.6 V, 5 Ah cells arranged as four series groups with two cells in parallel give 14.4 V nominal, 10 Ah and 144 Wh. Interconnect losses, cell variation and usable voltage limits are additional constraints." }, "url": "https://lemonergy.com/learn/glossary/series-parallel/", "mentions": [] } }, { "id": "term:coulomb", "type": "Term", "label": "Coulomb", "properties": { "id": "coulomb", "name": "Coulomb", "abbr": "C", "section": "topic-units", "definition": "The SI unit of electric charge; one ampere flowing for one second. Battery engineers prefer the ampere-hour, which is 3600 coulombs, because cells deliver their charge over hours.", "unit": "C", "related": [ "ampere-hour", "faradays-constant" ], "url": "https://lemonergy.com/learn/glossary/coulomb/", "mentions": [ "ampere", "electric-charge" ] } }, { "id": "term:joule", "type": "Term", "label": "Joule", "properties": { "id": "joule", "name": "Joule", "abbr": "J", "section": "topic-units", "definition": "The SI unit of energy; one watt for one second. Battery energy is almost always quoted in watt-hours instead, and 1 Wh equals 3600 J.", "unit": "J", "related": [ "watt-hour", "energy" ], "url": "https://lemonergy.com/learn/glossary/joule/", "mentions": [ "watt" ] } }, { "id": "visual:voltage", "type": "Visual", "label": "Voltage under load", "properties": { "title": "Voltage under load", "summary": "Discharge current creates an ohmic drop below open-circuit voltage.", "readout": "5 A through 20 mΩ gives 0.1 V ohmic drop.", "formula": "V_terminal = OCV − I_discharge R", "note": "Chosen OCV curve; no chemistry calibration, hysteresis or voltage cutoff.", "software": { "status": "studio", "label": "Voltage relationship in Studio", "body": "The native battery calculates terminal voltage from OCV and resistance. The curve here is an illustrative OCV relationship, not a fitted cell dataset.", "href": "https://design.lemonergy.com/cosim.html?example=charging-home" }, "html": "
Illustrative OCV and loaded voltage
Illustrative OCV and loaded voltageSOC (%) versus Voltage (V). Open circuit; Under load. Interpretation follows the graphs.1.802.42253.05503.67754.3100SOC (%)Voltage (V)
Open circuitUnder load (dashed)
" } }, { "id": "reference:bipm-si", "type": "Reference", "label": "The International System of Units (SI), 9th edition", "properties": { "title": "The International System of Units (SI), 9th edition", "publisher": "Bureau International des Poids et Mesures", "url": "https://doi.org/10.59161/AUEZ1291", "type": "Metrology reference", "scope": "Definitions of SI units and coherent derived units; 2026 revision.", "year": 2026, "accessed": "2026-10-27" } } ] }