{
  "node": {
    "id": "term:heat-pump",
    "type": "Term",
    "label": "Heat pump",
    "properties": {
      "id": "heat-pump",
      "name": "Heat pump",
      "aka": [
        "coefficient of performance"
      ],
      "section": "topic-thermal",
      "definition": "A refrigerant circuit run to move heat from a colder place to a warmer one, delivering two to three units of heat per unit of electricity in mild winter conditions. In an electric vehicle it warms the cabin and battery from outside air and the waste heat of the motor and inverter, saving winter range compared with resistive heaters.",
      "related": [
        "refrigerant-loop",
        "battery-heating",
        "preconditioning",
        "range",
        "chiller",
        "thermoelectric-cooling"
      ],
      "url": "https://lemonergy.com/learn/glossary/heat-pump/",
      "mentions": [
        "inverter",
        "electric-vehicle"
      ]
    }
  },
  "edges": [
    {
      "id": "edge:4723",
      "source": "term:heat-pump",
      "target": "topic:topic-thermal",
      "type": "belongsTo",
      "properties": {
        "sourceFile": "terms.json"
      }
    },
    {
      "id": "edge:4724",
      "source": "term:heat-pump",
      "target": "term:refrigerant-loop",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:4725",
      "source": "term:heat-pump",
      "target": "term:battery-heating",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:4726",
      "source": "term:heat-pump",
      "target": "term:preconditioning",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:4727",
      "source": "term:heat-pump",
      "target": "term:range",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:4728",
      "source": "term:heat-pump",
      "target": "term:chiller",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:4729",
      "source": "term:heat-pump",
      "target": "term:thermoelectric-cooling",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:mentions/heat-pump/inverter",
      "source": "term:heat-pump",
      "target": "term:inverter",
      "type": "mentions",
      "properties": {
        "sourceFile": "terms.json",
        "method": "build_glossary.mention_index + mentions",
        "field": "definition",
        "meaning": "Text mention; not a causal claim"
      }
    },
    {
      "id": "edge:mentions/heat-pump/electric-vehicle",
      "source": "term:heat-pump",
      "target": "term:electric-vehicle",
      "type": "mentions",
      "properties": {
        "sourceFile": "terms.json",
        "method": "build_glossary.mention_index + mentions",
        "field": "definition",
        "meaning": "Text mention; not a causal claim"
      }
    }
  ],
  "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:refrigerant-loop",
      "type": "Term",
      "label": "Refrigerant loop",
      "properties": {
        "id": "refrigerant-loop",
        "name": "Refrigerant loop",
        "aka": [
          "vapour-compression cycle",
          "air-conditioning circuit",
          "evaporator",
          "condenser",
          "compressor",
          "R1234yf",
          "R744"
        ],
        "section": "topic-thermal",
        "definition": "A closed vapour-compression circuit: a compressor raises refrigerant pressure and temperature, a condenser rejects that heat to air, an expansion valve drops the pressure, and an evaporator absorbs heat as the refrigerant boils. Batteries draw on it through a chiller or through refrigerant plates that act as evaporators; R1234yf and CO₂ (R744) are the usual refrigerants.",
        "related": [
          "chiller",
          "heat-pump",
          "heat-exchanger",
          "radiator",
          "thermal-management"
        ],
        "url": "https://lemonergy.com/learn/glossary/refrigerant-loop/",
        "mentions": []
      }
    },
    {
      "id": "term:battery-heating",
      "type": "Term",
      "label": "Battery heating",
      "properties": {
        "id": "battery-heating",
        "name": "Battery heating",
        "aka": [
          "battery heater",
          "pulse heating",
          "AC heating",
          "internal heating",
          "self-heating cell"
        ],
        "section": "topic-thermal",
        "definition": "Warming a cold battery before charging or use. External methods use electric heaters, a heat pump or warm coolant; internal methods heat the cell through its own resistance with alternating current or rapid charge–discharge pulses. Experimental self-heating cells embed a nickel foil that takes them from −20 °C to 0 °C in about 20 seconds.",
        "related": [
          "preconditioning",
          "heat-pump",
          "joule-heating",
          "lithium-plating",
          "operating-temperature",
          "thermal-management"
        ],
        "url": "https://lemonergy.com/learn/glossary/battery-heating/",
        "mentions": []
      }
    },
    {
      "id": "term:preconditioning",
      "type": "Term",
      "label": "Preconditioning",
      "properties": {
        "id": "preconditioning",
        "name": "Preconditioning",
        "section": "topic-thermal",
        "definition": "Warming or cooling the battery to its preferred temperature before a fast charge or a hard drive, using the vehicle’s own heaters and pumps. Navigating to a charger triggers it in many cars, because a cold pack cannot accept high current safely.",
        "related": [
          "thermal-management",
          "fast-charging",
          "lithium-plating",
          "operating-temperature"
        ],
        "url": "https://lemonergy.com/learn/glossary/preconditioning/",
        "mentions": [
          "charger"
        ]
      }
    },
    {
      "id": "term:range",
      "type": "Term",
      "label": "Range",
      "properties": {
        "id": "range",
        "name": "Range",
        "section": "topic-applications",
        "definition": "How far an electric vehicle travels on a full charge: usable energy divided by consumption per kilometre. Cold weather, speed and heating cut it, and the gap between official and real range is usually consumption, not battery capacity.",
        "unit": "km",
        "related": [
          "usable-capacity",
          "state-of-energy",
          "electric-vehicle",
          "energy-density",
          "energy-consumption-per-distance",
          "road-load-power"
        ],
        "url": "https://lemonergy.com/learn/glossary/range/",
        "mentions": []
      }
    },
    {
      "id": "term:chiller",
      "type": "Term",
      "label": "Chiller",
      "properties": {
        "id": "chiller",
        "name": "Chiller",
        "section": "topic-thermal",
        "definition": "A heat exchanger in which evaporating refrigerant from the air-conditioning circuit cools the battery coolant below ambient temperature. A radiator can only bring coolant close to outside air temperature; the chiller is what lets a pack fast-charge on a 35 °C day. Stationary storage containers use packaged chiller units for the same job.",
        "related": [
          "refrigerant-loop",
          "coolant",
          "radiator",
          "heat-exchanger",
          "fast-charging",
          "thermal-management"
        ],
        "url": "https://lemonergy.com/learn/glossary/chiller/",
        "mentions": [
          "stationary-storage"
        ]
      }
    },
    {
      "id": "term:thermoelectric-cooling",
      "type": "Term",
      "label": "Thermoelectric cooling",
      "properties": {
        "id": "thermoelectric-cooling",
        "name": "Thermoelectric cooling",
        "abbr": "TEC",
        "aka": [
          "Peltier cooling",
          "Peltier element",
          "Peltier module"
        ],
        "section": "topic-thermal",
        "definition": "Solid-state heat pumping by the Peltier effect: current through junctions of semiconductor elements moves heat from one face to the other, and reversing the current reverses the direction. Peltier modules hold small test cells at a set temperature in laboratory fixtures, but their efficiency, usually a coefficient of performance below 1, is too low for vehicle packs.",
        "related": [
          "heat-pump",
          "heat-sink",
          "thermal-management",
          "testing"
        ],
        "url": "https://lemonergy.com/learn/glossary/thermoelectric-cooling/",
        "mentions": []
      }
    },
    {
      "id": "term:inverter",
      "type": "Term",
      "label": "Inverter",
      "properties": {
        "id": "inverter",
        "name": "Inverter",
        "aka": [
          "power conversion system",
          "PCS"
        ],
        "section": "topic-pack",
        "definition": "The power electronics that turn the battery’s DC into AC for a motor or the grid, and back again for charging. In stationary storage it is called the power conversion system and its rating in kW or MW sets the system’s power independently of the battery’s energy.",
        "related": [
          "pre-charge",
          "dc-dc-converter",
          "stationary-storage",
          "energy-management-system",
          "direct-current",
          "iec-62477-1"
        ],
        "url": "https://lemonergy.com/learn/glossary/inverter/",
        "mentions": []
      }
    },
    {
      "id": "term:electric-vehicle",
      "type": "Term",
      "label": "Electric vehicle",
      "properties": {
        "id": "electric-vehicle",
        "name": "Electric vehicle",
        "abbr": "EV",
        "aka": [
          "BEV",
          "battery electric vehicle"
        ],
        "section": "topic-applications",
        "definition": "A vehicle driven by an electric motor from a battery charged from the grid. A battery electric vehicle has no engine; it is the largest market for lithium-ion cells and the driver of most pack technology.",
        "related": [
          "hybrid-vehicle",
          "range",
          "pack",
          "regenerative-braking",
          "maritime-battery",
          "industrial-vehicle-battery"
        ],
        "url": "https://lemonergy.com/learn/glossary/electric-vehicle/",
        "mentions": []
      }
    }
  ]
}