{
  "node": {
    "id": "term:ul-1973",
    "type": "Term",
    "label": "UL 1973",
    "properties": {
      "id": "ul-1973",
      "name": "UL 1973",
      "section": "topic-standards-stationary",
      "definition": "The North American safety standard for batteries in stationary storage, vehicle auxiliary power and light electric rail, covering cells, modules and the battery system with its management electronics. It centres on functional safety analysis of hardware and software alongside abuse tests, and a UL 1973 battery is what UL 9540 expects inside a complete energy storage system.",
      "related": [
        "ul-9540",
        "ul-9540a",
        "iec-62619",
        "stationary-storage",
        "bms",
        "ul-1741"
      ],
      "url": "https://lemonergy.com/learn/glossary/ul-1973/",
      "mentions": [
        "functional-safety"
      ]
    }
  },
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      "id": "edge:6439",
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        "meaning": "Related context; not a causal claim"
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      "source": "term:ul-1973",
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      "id": "edge:6443",
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      "id": "edge:6444",
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  "neighbors": [
    {
      "id": "topic:topic-standards-stationary",
      "type": "Topic",
      "label": "Stationary, industrial and product standards",
      "properties": {
        "id": "topic-standards-stationary",
        "name": "Stationary, industrial and product standards",
        "lede": "Safety and performance standards for portable, industrial and grid batteries, their electronics and their installation.",
        "context": "Match scope to product and installation.",
        "example": "A cell-level test does not establish fire performance or commissioning requirements for a complete installation.",
        "lesson_url": "https://lemonergy.com/learn/fundamentals/battery-basics/",
        "lesson_label": "Open battery basics"
      }
    },
    {
      "id": "term:ul-9540",
      "type": "Term",
      "label": "UL 9540",
      "properties": {
        "id": "ul-9540",
        "name": "UL 9540",
        "section": "topic-standards-stationary",
        "definition": "The North American product safety standard for a complete energy storage system — battery, inverter and controls together — as opposed to UL 9540A, which is the test method for its thermal-runaway behaviour. Listing to UL 9540 is what most US fire codes require for installation.",
        "related": [
          "ul-9540a",
          "nfpa-855",
          "stationary-storage",
          "inverter",
          "pas-63100"
        ],
        "url": "https://lemonergy.com/learn/glossary/ul-9540/",
        "mentions": []
      }
    },
    {
      "id": "term:ul-9540a",
      "type": "Term",
      "label": "UL 9540A",
      "properties": {
        "id": "ul-9540a",
        "name": "UL 9540A",
        "section": "topic-standards-stationary",
        "definition": "A test method, not a pass/fail standard, that characterises thermal runaway and propagation in stationary storage at cell, module, unit and installation level. Fire codes use its data to decide spacing and suppression for a storage site.",
        "related": [
          "thermal-propagation",
          "stationary-storage",
          "fire-suppression",
          "propagation-test",
          "nfpa-855"
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        "url": "https://lemonergy.com/learn/glossary/ul-9540a/",
        "mentions": [
          "thermal-runaway"
        ]
      }
    },
    {
      "id": "term:iec-62619",
      "type": "Term",
      "label": "IEC 62619",
      "properties": {
        "id": "iec-62619",
        "name": "IEC 62619",
        "section": "topic-standards-stationary",
        "definition": "The safety standard for secondary lithium cells and batteries in industrial applications — stationary storage, forklifts, rail and marine — covering cell abuse tests plus battery-system functions such as overcharge and thermal control. It is the industrial counterpart of IEC 62133 for portable and IEC 62660 for vehicles.",
        "related": [
          "iec-62133",
          "iec-62660",
          "stationary-storage",
          "conformity-assessment",
          "iec-63056",
          "en-62040-1"
        ],
        "url": "https://lemonergy.com/learn/glossary/iec-62619/",
        "mentions": [
          "overcharge"
        ]
      }
    },
    {
      "id": "term:stationary-storage",
      "type": "Term",
      "label": "Stationary storage",
      "properties": {
        "id": "stationary-storage",
        "name": "Stationary storage",
        "abbr": "BESS",
        "aka": [
          "battery energy storage system",
          "ESS"
        ],
        "section": "topic-applications",
        "definition": "Batteries installed in a fixed place — a container at a solar farm, a cabinet in a home — to shift energy in time or support the grid. LFP cells dominate because cost per cycle and safety matter more than mass.",
        "related": [
          "lfp",
          "energy-management-system",
          "inverter",
          "energy-arbitrage",
          "long-duration-storage",
          "ul-9540a"
        ],
        "url": "https://lemonergy.com/learn/glossary/stationary-storage/",
        "mentions": []
      }
    },
    {
      "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:ul-1741",
      "type": "Term",
      "label": "UL 1741",
      "properties": {
        "id": "ul-1741",
        "name": "UL 1741",
        "aka": [
          "UL 1741 SB",
          "UL 1741 SA"
        ],
        "section": "topic-standards-stationary",
        "definition": "The North American safety standard for inverters, converters, charge controllers and interconnection equipment used with distributed energy resources such as solar and battery storage. Its Supplement SB certifies grid-support functions, such as ride-through and voltage and frequency response, against the tests of IEEE 1547.1-2020, taking over from the earlier Supplement SA.",
        "related": [
          "inverter",
          "ul-9540",
          "stationary-storage",
          "frequency-regulation",
          "vehicle-to-grid"
        ],
        "url": "https://lemonergy.com/learn/glossary/ul-1741/",
        "mentions": []
      }
    },
    {
      "id": "term:functional-safety",
      "type": "Term",
      "label": "Functional safety",
      "properties": {
        "id": "functional-safety",
        "name": "Functional safety",
        "abbr": "ISO 26262",
        "aka": [
          "ASIL"
        ],
        "section": "topic-hvsafety",
        "definition": "The discipline, standardised for vehicles in ISO 26262, of making sure electronic failures do not cause harm. Battery functions such as overvoltage protection are classified by risk into ASIL levels A to D, which set how redundant and verified their hardware and software must be.",
        "related": [
          "bms",
          "high-voltage-interlock",
          "insulation-resistance",
          "fmea",
          "mcu",
          "iso-13849"
        ],
        "url": "https://lemonergy.com/learn/glossary/functional-safety/",
        "mentions": []
      }
    },
    {
      "id": "reference:ul-storage",
      "type": "Reference",
      "label": "Energy Storage System Testing and Certification",
      "properties": {
        "title": "Energy Storage System Testing and Certification",
        "publisher": "UL Solutions",
        "url": "https://www.ul.com/services/energy-storage-system-testing-and-certification",
        "type": "Official documentation",
        "scope": "System safety scope of UL 9540 and relationships to battery and power-conversion standards.",
        "accessed": "2026-10-27"
      }
    }
  ]
}