{ "node": { "id": "term:busbar", "type": "Term", "label": "Busbar", "properties": { "id": "busbar", "name": "Busbar", "section": "topic-pack", "definition": "A rigid copper or aluminium conductor that joins cell terminals into series and parallel groups, and modules into the pack. Its cross-section is sized for current and heating, and its joints — welded or bolted — are a classic source of resistance and failure.", "related": [ "series-parallel", "terminal", "laser-welding", "internal-resistance", "wire-bonding" ], "url": "https://lemonergy.com/learn/glossary/busbar/", "mentions": [] } }, "edges": [ { "id": "edge:2898", "source": "term:busbar", "target": "topic:topic-pack", "type": "belongsTo", "properties": { "sourceFile": "terms.json" } }, { "id": "edge:2899", "source": "term:busbar", "target": "term:series-parallel", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:2900", "source": "term:busbar", "target": "term:terminal", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:2901", "source": "term:busbar", "target": "term:laser-welding", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:2902", "source": "term:busbar", "target": "term:internal-resistance", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:2903", "source": "term:busbar", "target": "term:wire-bonding", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:2904", "source": "term:busbar", "target": "visual:heat", "type": "illustratedBy", "properties": { "sourceFile": "visual-pages.json" } } ], "neighbors": [ { "id": "topic:topic-pack", "type": "Topic", "label": "Modules, packs and battery management", "properties": { "id": "topic-pack", "name": "Modules, packs and battery management", "lede": "From a single cell to a working battery system, and the electronics that keep it safe.", "context": "Make series/parallel architecture explicit.", "example": "Twelve 3.6 V, 5 Ah cells in 6s2p give 21.6 V, 10 Ah and 216 Wh nominally before other restrictions.", "lesson_url": "https://lemonergy.com/learn/fundamentals/cell-architecture/", "lesson_label": "Open cell architecture" } }, { "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:terminal", "type": "Term", "label": "Terminal", "properties": { "id": "terminal", "name": "Terminal", "section": "topic-components", "definition": "The external conductor through which current enters and leaves the cell: the can and cap of a cylindrical cell, two posts on a prismatic cell, or the sealed foil tabs of a pouch cell.", "related": [ "tab", "busbar", "voltage" ], "url": "https://lemonergy.com/learn/glossary/terminal/", "mentions": [ "cylindrical-cell", "prismatic-cell", "pouch-cell" ] } }, { "id": "term:laser-welding", "type": "Term", "label": "Laser welding", "properties": { "id": "laser-welding", "name": "Laser welding", "section": "topic-manufacturing", "definition": "Joining metal with a focused laser beam, used to seal cans, attach caps and connect busbars to cell terminals. It is fast and precise but sensitive to gaps and reflectivity, so copper joints need special wavelengths or beam shaping.", "related": [ "ultrasonic-welding", "tab-welding", "busbar", "can" ], "url": "https://lemonergy.com/learn/glossary/laser-welding/", "mentions": [] } }, { "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:wire-bonding", "type": "Term", "label": "Wire bonding", "properties": { "id": "wire-bonding", "name": "Wire bonding", "aka": [ "wire bond", "fusible link" ], "section": "topic-manufacturing", "definition": "Connecting each cell terminal to a busbar or collector plate with a thin aluminium wire, often a few hundred micrometres thick, attached ultrasonically at both ends. The wire can be sized to act as a fuse, so a cell that shorts internally is cut off from its parallel neighbours; Tesla’s cylindrical-cell packs are the best-known example.", "related": [ "ultrasonic-welding", "busbar", "fuse", "cylindrical-cell", "series-parallel" ], "url": "https://lemonergy.com/learn/glossary/wire-bonding/", "mentions": [] } }, { "id": "visual:heat", "type": "Visual", "label": "Current and resistive heating", "properties": { "title": "Current and resistive heating", "summary": "Double the current and ohmic heating increases fourfold.", "readout": "At 5 A: 0.5 W. At 10 A: 2 W.", "formula": "P_heat = I²R", "note": "Resistance is constant; reversible entropic heat and other losses are excluded.", "software": { "status": "reference", "label": "Reference concept", "body": "P = I²R is the ohmic contribution. The product Charge session can also use a lumped thermal model; the native Studio battery does not calculate temperature evolution.", "href": "https://design.lemonergy.com/" }, "html": "
Ohmic heating
Ohmic heatingCurrent magnitude (A) versus Heat rate (W). I²R. Interpretation follows the graphs.0025410615820Current magnitude (A)Heat rate (W)
I²R
" } } ] }