In short
Store lithium-ion batteries at partial charge, in a cool and dry place, away from combustible materials, with damaged cells kept separate. Charge them where a failure would be noticed and contained rather than where it would block an escape route. Follow the manufacturer’s figures over any general rule of thumb.
This is where most of the practical risk sits, and where the cheapest improvements are available.
A workplace that changes nothing about its cabinets but moves charging out of the corridor, bans marketplace chargers and separates damaged packs has reduced its exposure more than one that buys a cabinet and carries on as before.
The four variables that matter
State of charge
A cell held at full charge ages faster and holds more energy that can be released if it fails. For anything going into storage for weeks or months, partial charge is the standard recommendation. Manufacturers publish their own figures and they differ between chemistries and product lines, so use the figure on the datasheet rather than a number from a forum. Detail on storage temperature and voltage.
Temperature
Cool and stable beats warm, and warm beats cycling between extremes. Heat accelerates the internal degradation that eventually causes failures, so the worst common storage locations are the ones nobody thinks about: a container in direct sun, a cupboard above a heater, a van left out in July. Cold is generally less damaging to store at, but charging a cold cell is its own hazard — bring packs to room temperature before charging.
Separation
Two kinds. Separation from combustibles, so a failure does not immediately have fuel — cardboard, packaging, timber and aerosols are the usual offenders in a stockroom. And separation between packs, so one failing does not take the shelf with it. Physical distance is the cheapest fire break available, and it costs floor space rather than money.
Condition
Damaged, swollen, dropped, water-affected and end-of-life packs are a different category and should not be stored with healthy stock. They need a defined quarantine location, and they fall under the Waste Batteries and Accumulators Regulations 2009 once they are waste. Decide where they go before you need somewhere to put one.
Charging at work
Charging is when a battery is most likely to fail, and when a fault has energy behind it. The controls are mostly about location and supervision rather than equipment.
- Charge away from escape routes, final exits, stairwells and sleeping accommodation. This is the single most consequential decision on the list.
- Use the charger supplied with the pack. Substandard and counterfeit chargers recur throughout UK incident reporting; Electrical Safety First publishes ongoing evidence on this.
- Avoid unattended overnight charging, or provide detection that alerts someone who can act.
- Do not charge damaged packs at all. A swollen pack going on charge is the scenario most likely to end badly.
- Where charging volume justifies it, a charging cabinet puts the activity inside a tested enclosure with managed ventilation and isolation.
Read next
- How to store lithium batteries — the step-by-step version of this page.
- Storage temperature and voltage — what the numbers actually mean.
- LiPo battery storage — pouch packs, storage mode, and what a “LiPo safe” bag is really doing.
- Battery cabinets — when containment is worth buying, and how to size it.
- Regulations — the duties that make these arrangements a legal matter rather than a preference.
Frequently asked questions
Can I store lithium batteries in a normal metal cupboard?
You can, and for small quantities of healthy packs kept away from combustibles it may be a reasonable control. What a plain cupboard does not do is contain a failure: it has no tested fire resistance, no managed ventilation and no barrier between packs. As quantity or energy content rises, the gap between “tidy” and “contained” starts to matter, which is the point at which a tested cabinet earns its cost.
Should batteries be stored fully charged or empty?
Neither. Full charge accelerates ageing and stores maximum energy; fully flat risks over-discharge, which can damage cells and make later charging hazardous. Partial charge is the general recommendation, with the specific figure taken from the manufacturer’s datasheet for that product.
Is it safe to store batteries in an outbuilding or shipping container?
It can be a good option because it separates the risk from occupied buildings, which is exactly what you want. The catch is temperature: an uninsulated container in summer can reach temperatures well outside any manufacturer’s storage range, and cycling between hot days and cold nights is worse for cells than a stable indoor space. If you go this route, address insulation, ventilation and monitoring rather than treating distance alone as the control.
How long can lithium batteries be stored?
Indefinitely in principle, but capacity falls over time and the rate depends on temperature and state of charge. For long-term storage, plan a periodic check: inspect for swelling or damage, and top packs back up to the recommended storage charge before they drift into over-discharge. Six-monthly is a common interval; the manufacturer’s guidance takes precedence.