{ "node": { "id": "term:temperature-sensor", "type": "Term", "label": "Temperature sensor", "properties": { "id": "temperature-sensor", "name": "Temperature sensor", "abbr": "NTC", "aka": [ "thermistor" ], "section": "topic-thermal", "definition": "Usually a negative-temperature-coefficient thermistor glued to a busbar or cell surface, with a few per module. Because sensors read the surface, the hottest point inside a cell can run several degrees higher than the BMS sees.", "unit": "°C", "related": [ "bms", "thermal-management", "operating-temperature", "derating", "thermocouples-rtds", "virtual-temperature-sensor" ], "url": "https://lemonergy.com/learn/glossary/temperature-sensor/", "mentions": [ "busbar" ] } }, "edges": [ { "id": "edge:2863", "source": "term:temperature-sensor", "target": "topic:topic-thermal", "type": "belongsTo", "properties": { "sourceFile": "terms.json" } }, { "id": "edge:2864", "source": "term:temperature-sensor", "target": "term:bms", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:2865", "source": "term:temperature-sensor", "target": "term:thermal-management", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:2866", "source": "term:temperature-sensor", "target": "term:operating-temperature", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:2867", "source": "term:temperature-sensor", "target": "term:derating", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:2868", "source": "term:temperature-sensor", "target": "term:thermocouples-rtds", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:2869", "source": "term:temperature-sensor", "target": "term:virtual-temperature-sensor", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:mentions/temperature-sensor/busbar", "source": "term:temperature-sensor", "target": "term:busbar", "type": "mentions", "properties": { "sourceFile": "terms.json", "method": "build_glossary.mention_index + mentions", "field": "definition", "meaning": "Text mention; not a causal claim" } }, { "id": "edge:2871", "source": "term:temperature-sensor", "target": "visual:derating", "type": "illustratedBy", "properties": { "sourceFile": "visual-pages.json" } } ], "neighbors": [ { "id": "topic:topic-thermal", "type": "Topic", "label": "Thermal management and heat transfer", "properties": { "id": "topic-thermal", "name": "Thermal management and heat transfer", "lede": "How heat is made, moved and removed in cells and packs, and the hardware that keeps a battery at the right temperature.", "context": "Select spatial detail for the question.", "example": "Equal total heat in different layouts can produce different gradients. Average temperature can miss a hot spot.", "lesson_url": "https://lemonergy.com/learn/fundamentals/battery-aging/", "lesson_label": "Open temperature and aging" } }, { "id": "term:bms", "type": "Term", "label": "Battery management system", "properties": { "id": "bms", "name": "Battery management system", "abbr": "BMS", "section": "topic-pack", "definition": "The electronics and software that keep a battery inside its safe window: measuring every cell voltage and many temperatures, estimating SOC and SOH, balancing cells, computing current limits, controlling the contactors and reporting over the vehicle network.", "related": [ "state-of-charge", "cell-balancing", "state-of-power", "cell-supervision-circuit", "contactor", "can-bus" ], "lesson": "fundamentals/battery-basics/#cell-module-pack", "url": "https://lemonergy.com/learn/glossary/bms/", "mentions": [ "state-of-health", "cell-voltage" ] } }, { "id": "term:thermal-management", "type": "Term", "label": "Thermal management", "properties": { "id": "thermal-management", "name": "Thermal management", "abbr": "TMS", "aka": [ "battery thermal management system", "BTMS" ], "section": "topic-thermal", "definition": "Keeping cells in their comfortable range, roughly 15–35 °C, and within a few degrees of each other: liquid cooling plates, refrigerant plates or immersion for heat removal, and heaters or waste heat for warming before fast charging in the cold.", "related": [ "cooling-plate", "thermal-interface-material", "operating-temperature", "heat-generation", "preconditioning", "temperature-sensor" ], "url": "https://lemonergy.com/learn/glossary/thermal-management/", "mentions": [ "fast-charging" ] } }, { "id": "term:operating-temperature", "type": "Term", "label": "Operating temperature", "properties": { "id": "operating-temperature", "name": "Operating temperature", "section": "topic-ratings", "definition": "The temperature range a cell may be charged and discharged in, typically 0–45 °C for charging and −20–60 °C for discharging. Charging below 0 °C risks lithium plating; above the range the cell ages fast and may vent.", "unit": "°C", "related": [ "lithium-plating", "arrhenius", "thermal-management", "datasheet" ], "lesson": "fundamentals/battery-aging/#temperature", "url": "https://lemonergy.com/learn/glossary/operating-temperature/", "mentions": [] } }, { "id": "term:derating", "type": "Term", "label": "Derating", "properties": { "id": "derating", "name": "Derating", "section": "topic-pack", "definition": "Reducing the allowed charge or discharge power as the battery approaches a limit — low temperature, high temperature, high or low SOC, or age. It is how a BMS keeps the cells safe while letting the vehicle do as much as it can.", "related": [ "state-of-power", "bms", "operating-temperature", "fast-charging", "limp-home-mode" ], "url": "https://lemonergy.com/learn/glossary/derating/", "mentions": [ "state-of-charge" ] } }, { "id": "term:thermocouples-rtds", "type": "Term", "label": "Thermocouples, RTDs and fibre-optic sensors", "properties": { "id": "thermocouples-rtds", "name": "Thermocouples, RTDs and fibre-optic sensors", "aka": [ "thermocouple", "RTD", "Pt100", "resistance temperature detector", "fibre Bragg grating", "FBG" ], "section": "topic-thermal", "definition": "Temperature sensors used alongside the NTC thermistors of a BMS. Thermocouples, junctions of two dissimilar wires such as type K or T, are cheap, small and standard in cell testing, good to about ±1–2 °C; platinum RTDs such as the Pt100 reach a few tenths of a degree; fibre-optic sensors ignore electrical noise and can sit inside a cell.", "related": [ "temperature-sensor", "thermography", "testing", "bms" ], "url": "https://lemonergy.com/learn/glossary/thermocouples-rtds/", "mentions": [] } }, { "id": "term:virtual-temperature-sensor", "type": "Term", "label": "Virtual temperature sensor", "properties": { "id": "virtual-temperature-sensor", "name": "Virtual temperature sensor", "aka": [ "soft sensor", "core temperature estimation", "sensorless temperature estimation" ], "section": "topic-state", "definition": "A temperature computed rather than measured: a thermal model fed with current, coolant temperature and the readings of nearby sensors infers the temperature of cells, or cell cores, that carry no sensor. Packs often fit one thermistor for several cells, and a large cell’s core runs hotter than its surface under load, so derating depends on such estimates.", "related": [ "temperature-sensor", "thermal-model", "derating", "bms", "digital-twin" ], "url": "https://lemonergy.com/learn/glossary/virtual-temperature-sensor/", "mentions": [] } }, { "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": [] } }, { "id": "visual:derating", "type": "Visual", "label": "The limit sets the permitted current", "properties": { "title": "The limit sets the permitted current", "summary": "A requested current is clipped wherever an active limit is lower.", "readout": "Requested current: 8 A. At 50 °C the chosen limit permits 5 A.", "formula": "I_command = min(I_requested, I_limit)", "note": "Breakpoints are invented teaching values, not operating limits for a particular battery.", "software": { "status": "reference", "label": "Reference concept", "body": "A BMS can combine temperature, voltage and equipment limits. The selected breakpoints illustrate logic only; actual limits must be cell-specific.", "href": "https://lemonergy.com/wiki/charging-strategies/" }, "html": "
Illustrative temperature current limit
Illustrative temperature current limitTemperature (°C) versus Current (A). Limit; Permitted command. Interpretation follows the graphs.0-1037.5625942.51260Temperature (°C)Current (A)
LimitPermitted command (dashed)
" } } ] }