{
  "node": {
    "id": "term:voltage-hysteresis",
    "type": "Term",
    "label": "Voltage hysteresis",
    "properties": {
      "id": "voltage-hysteresis",
      "name": "Voltage hysteresis",
      "section": "topic-charging",
      "definition": "The difference between the open-circuit voltage reached from charging and from discharging at the same state of charge. It is small for most lithium-ion chemistries but large for LFP and silicon, and it limits how precisely voltage can give SOC.",
      "related": [
        "open-circuit-voltage",
        "ocv-soc-curve",
        "lfp",
        "silicon-anode",
        "energy-efficiency"
      ],
      "url": "https://lemonergy.com/learn/glossary/voltage-hysteresis/",
      "mentions": [
        "state-of-charge"
      ]
    }
  },
  "edges": [
    {
      "id": "edge:1143",
      "source": "term:voltage-hysteresis",
      "target": "topic:topic-charging",
      "type": "belongsTo",
      "properties": {
        "sourceFile": "terms.json"
      }
    },
    {
      "id": "edge:1144",
      "source": "term:voltage-hysteresis",
      "target": "term:open-circuit-voltage",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:1145",
      "source": "term:voltage-hysteresis",
      "target": "term:ocv-soc-curve",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:1146",
      "source": "term:voltage-hysteresis",
      "target": "term:lfp",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:1147",
      "source": "term:voltage-hysteresis",
      "target": "term:silicon-anode",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:1148",
      "source": "term:voltage-hysteresis",
      "target": "term:energy-efficiency",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:mentions/voltage-hysteresis/state-of-charge",
      "source": "term:voltage-hysteresis",
      "target": "term:state-of-charge",
      "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-charging",
      "type": "Topic",
      "label": "Charging and discharging",
      "properties": {
        "id": "topic-charging",
        "name": "Charging and discharging",
        "lede": "How current goes in and comes out, and the limits that stop it.",
        "context": "Separate regulation from availability.",
        "example": "The same CC–CV law can operate overnight or during a short depot stop.",
        "lesson_url": "https://lemonergy.com/learn/fundamentals/capacity-and-c-rate/",
        "lesson_label": "Open charging quantities"
      }
    },
    {
      "id": "term:open-circuit-voltage",
      "type": "Term",
      "label": "Open-circuit voltage",
      "properties": {
        "id": "open-circuit-voltage",
        "name": "Open-circuit voltage",
        "abbr": "OCV",
        "section": "topic-state",
        "definition": "The voltage across a cell’s terminals when no current flows and the cell has rested long enough for the voltage to settle. It depends on state of charge and temperature, and a cell whose open-circuit voltage falls unusually fast in storage may have an internal short.",
        "unit": "V",
        "related": [
          "ocv-soc-curve",
          "relaxation",
          "voltage-hysteresis",
          "k-value",
          "internal-short-circuit"
        ],
        "lesson": "fundamentals/cell-production/#finishing",
        "url": "https://lemonergy.com/learn/glossary/open-circuit-voltage/",
        "mentions": [
          "state-of-charge"
        ]
      }
    },
    {
      "id": "term:ocv-soc-curve",
      "type": "Term",
      "label": "OCV–SOC curve",
      "properties": {
        "id": "ocv-soc-curve",
        "name": "OCV–SOC curve",
        "section": "topic-state",
        "definition": "The characteristic relation between a cell’s open-circuit voltage and its state of charge, measured once at low current and stored in the BMS. A steep curve, as for NMC, makes SOC easy to read from voltage; LFP’s flat curve does not.",
        "related": [
          "open-circuit-voltage",
          "state-of-charge",
          "coulomb-counting",
          "lfp",
          "voltage-plateau",
          "ocv-test"
        ],
        "url": "https://lemonergy.com/learn/glossary/ocv-soc-curve/",
        "mentions": [
          "bms"
        ]
      }
    },
    {
      "id": "term:lfp",
      "type": "Term",
      "label": "LFP",
      "properties": {
        "id": "lfp",
        "name": "LFP",
        "aka": [
          "lithium iron phosphate",
          "LiFePO₄"
        ],
        "section": "topic-chemistries",
        "definition": "A positive electrode material, LiFePO₄, giving cells a nominal voltage around 3.2 V, long cycle life and good thermal stability, but less energy per kilogram than nickel-rich oxides. Its flat voltage curve makes state of charge hard to read from voltage alone.",
        "related": [
          "cathode-active-material",
          "nmc",
          "lmfp",
          "ocv-soc-curve",
          "cycle-life"
        ],
        "lesson": "fundamentals/cell-anatomy/#voltage",
        "example": {
          "title": "Chemistry is not the whole datasheet",
          "text": "Two LFP products can differ in format, loading, capacity and current limits. Their cathode family alone does not make them interchangeable."
        },
        "url": "https://lemonergy.com/learn/glossary/lfp/",
        "mentions": [
          "electrode",
          "positive-electrode",
          "nominal-voltage",
          "discharge-curve",
          "state-of-charge"
        ]
      }
    },
    {
      "id": "term:silicon-anode",
      "type": "Term",
      "label": "Silicon anode",
      "properties": {
        "id": "silicon-anode",
        "name": "Silicon anode",
        "aka": [
          "silicon-graphite",
          "SiOx"
        ],
        "section": "topic-components",
        "definition": "A negative electrode that uses silicon, which alloys with lithium and stores roughly ten times more charge per gram than graphite but swells by up to 300 %. Today it is blended into graphite at a few percent to limit the swelling.",
        "related": [
          "graphite",
          "alloying",
          "particle-cracking",
          "swelling",
          "self-healing-binder"
        ],
        "example": {
          "title": "Read the mixture basis",
          "text": "A silicon-containing electrode may be a blend rather than pure silicon. A silicon percentage needs a clear mass basis."
        },
        "url": "https://lemonergy.com/learn/glossary/silicon-anode/",
        "mentions": [
          "electrode",
          "negative-electrode"
        ]
      }
    },
    {
      "id": "term:energy-efficiency",
      "type": "Term",
      "label": "Energy efficiency",
      "properties": {
        "id": "energy-efficiency",
        "name": "Energy efficiency",
        "aka": [
          "round-trip efficiency"
        ],
        "section": "topic-ratings",
        "definition": "Energy out divided by energy in over a full cycle. It is lower than coulombic efficiency because the charge voltage sits above the discharge voltage; cells reach 95–98 %, and a full storage system 85–92 % after power electronics and cooling.",
        "unit": "%",
        "related": [
          "coulombic-efficiency",
          "voltage-hysteresis",
          "ir-drop",
          "stationary-storage",
          "voltage-efficiency"
        ],
        "url": "https://lemonergy.com/learn/glossary/energy-efficiency/",
        "mentions": []
      }
    },
    {
      "id": "term:state-of-charge",
      "type": "Term",
      "label": "State of charge",
      "properties": {
        "id": "state-of-charge",
        "name": "State of charge",
        "abbr": "SOC",
        "section": "topic-state",
        "definition": "How full a cell is, as a fraction of its available capacity. State of charge, like temperature, affects how fast a stored cell ages.",
        "unit": "%",
        "related": [
          "depth-of-discharge",
          "ocv-soc-curve",
          "coulomb-counting",
          "state-of-health",
          "bms"
        ],
        "lesson": "fundamentals/battery-aging/#storage-soc",
        "example": {
          "title": "Interpret a charge inventory",
          "text": "If available capacity is 5 Ah and 3 Ah remains by the chosen estimator, SOC is 60%. A different estimate of available capacity changes this percentage, so compare SOC values only with the capacity convention recorded."
        },
        "url": "https://lemonergy.com/learn/glossary/state-of-charge/",
        "mentions": [
          "usable-capacity"
        ]
      }
    }
  ]
}