Risk Assessment, Storage, and Charging of Lithium-Ion Batteries

1. Purpose of this Guide

Lithium-ion batteries are highly efficient, but they must be handled, stored, and charged safely. This document provides practical advice for customers on carrying out risk assessments, setting up safe battery storage, and creating charging arrangements, including where unattended charging may be considered.

Disclaimer

This guidance is advisory only and must be adapted to each customer’s site and operational requirements. Responsibility for carrying out the risk assessment and implementing control measures rests with the customer.

2. Risk Assessment Requirements

Before setting up a battery store or charging area, customers should carry out a site-specific risk assessment. This should cover:

• Hazard Identification
  • Fire risk from thermal runaway.
  • Electrical faults in chargers.
  • Mechanical damage to cells (puncture, crushing).
  • Environmental factors (temperature, humidity, water ingress).
• Likelihood & Severity
  • Assess likelihood of failure (age of batteries, charging cycles, manufacturer guidance).
  • Assess severity (spread of fire, exposure to people, critical systems).
• Control Measures
  • Safe storage containers.
  • Fire suppression or detection systems.
  • Procedures for charging supervision.
  • Emergency response plan (evacuation, fire brigade notification).
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Tip: Customers may follow frameworks such as HSE guidance (UK), NFPA 855 (US), or local equivalents.

3. Battery Storage

• Dedicated Location
  • Use a dedicated battery store, separate from offices, sleeping areas, or combustible materials.
  • Ensure adequate ventilation to avoid gas buildup in case of venting.
• Battery Safes / Cabinets
  • Use metal fire-rated battery cabinets or safes designed for lithium-ion storage.
  • Where possible, store each battery in fire-resistant pouches or boxes.
  • Include signage: “Lithium-Ion Battery Store – Fire Risk”.
• Environmental Conditions
  • Keep between 10 °C and 30 °C.
  • Avoid direct sunlight, heaters, or damp areas.
• Segregation
  • Separate new, in-use, and end-of-life batteries.
  • Damaged or suspect batteries must be isolated in a fireproof container and disposed of via approved waste channels.

4. Charging Systems

• Approved Chargers Only
  • Always use the charger supplied or approved for the specific battery.
  • Avoid unverified “universal” chargers.
• Safe Charging Area
  • Place chargers in a dedicated, non-combustible area (e.g. metal bench, ceramic tile surface).
  • Keep away from flammable materials (paper, solvents, plastics).
• Ventilation & Space
  • Allow free air circulation around chargers.
  • Do not stack batteries while charging.
• Supervision
  • Ideally, charging should be attended.
  • If charging multiple units, stagger cycles to reduce load and monitoring requirements.

5. Unattended Charging Considerations

If a customer must charge unattended (e.g., overnight):

• Enhanced Risk Controls
  • Use fire-resistant charging cabinets designed for lithium-ion batteries.
  • Install smoke/heat detection and link to building alarms.
  • Ensure automatic shut-off (smart chargers with over-temperature and over-voltage protection).
  • Consider external storage/charging containers located away from main buildings.
• Policy & Monitoring
  • Formal approval from the organisation’s health & safety officer.
  • Documented procedure and risk acceptance.
  • Regular inspection of chargers and batteries for damage.

6. Emergency Planning

• Fire Response
  • In the event of smoke, hissing, or fire, evacuate immediately.
  • Do not attempt to extinguish a lithium-ion fire with water – use Class D or lithium-rated extinguishers if trained.
  • Always call emergency services.
• Incident Documentation
  • Record all incidents, even near-misses, in the site safety log.
  • Review and update risk assessment accordingly.

7. Summary Checklist

✔ Carry out a documented risk assessment.

✔ Store batteries in fire-resistant cabinets, away from heat and flammables.

✔ Use only approved chargers in a ventilated area.

✔ Supervise charging where possible; if not, implement additional safety controls.

✔ Plan for emergencies with alarms, extinguishers, and evacuation procedures.