With the rise of electric vehicles, lithium batteries have become an increasingly important part of our daily lives. As convenient as they may be, lithium batteries require proper care and storage to ensure safety and longevity. In this comprehensive guide, as a professional lithium battery packs manufacturer, I’ll share my top tips on how to store lithium batteries correctly based on the latest research and industry standards.
Why Proper Lithium Battery Storage Matters
Before jumping into the storage specifics, it’s worth understanding why paying attention to storage conditions is so critical for lithium batteries.
Unlike lead-acid batteries, lithium-ion and lithium polymer batteries are far more sensitive to suboptimal handling. Issues like overcharging, excessive heat, internal shorts, and physical damage can all contribute to a condition called “thermal runaway”.
Essentially, the battery enters an uncontrolled state leading to overheating, gassing, bloating, leakage, and in extreme cases even fire or explosion. Yikes!
Once a battery goes into thermal runaway, the chemical reactions are almost impossible to stop. So prevention is key by always adhering to safe usage and storage.
By following the simple best practices below, you can avoid accelerated aging of your batteries and keep them running safely for years.
How to Safely Store Lithium Battery
Store Lithium Batteries at Moderate Temperatures
The number one environmental factor in lithium battery storage is temperature control. Both extreme heat and extreme cold should be avoided.
The ideal storage temperature range for lithium batteries is 15°C to 25°C or 59°F to 77°F. This temperature band allows the sensitive chemical components inside the battery to remain most stable.
Storing lithium batteries above 30°C/86°F causes accelerated self-discharging and aging especially if kept at higher temperatures for extended periods
On the other end of the spectrum, freezing temperatures below 0°C/32°F can significantly reduce a lithium battery’s power delivery and ability to hold charge.
So find an indoor storage location such as a closet or pantry that roughly fits in that 15°C to 25°C/59°F to 77°F goldilocks zone. Avoid placing batteries next to heat sources like radiators or appliances.
If environment temperature variations exceed that optimal zone during winter or summer months, consider a temperature-controlled storage container to shield your lithium batteries from both temperature and humidity extremes.
Keep Batteries Between 40-50% Charge Level
Much like temperature exposure, the current charge level or “state of charge” (SoC) also plays a role in preserving lithium battery lifespan and safety characteristics.
I recommend keeping stored lithium batteries at a 40-50% SoC rather than fully charged or fully drained. This middle ground charge helps stabilize battery chemistry and prevents cell voltage dropping too low over time which can lead to premature capacity loss.
Before packing batteries away for storage, use a voltmeter to check each cell or battery pack’s current voltage level and refer to the product manual for the equivalent SoC percentage.
Top up charging closer to 50% if the current reading falls below 40%. Likewise for long-term storage beyond 3-4 months, check voltages quarterly and recharge as needed.
Bulk chargers can help streamline simultaneous charging and discharging for lithium battery banks rather than handling each battery or cell individually.
Maintaining an approximate 50% charge ensures stored batteries remain primed for quick deployment when needed rather than requiring a full recharge. But also prevents electrical strain that continuously “topping off” at 100% SoC would cause.
Use Non-Conductive Dividers During Storage
One of the inherent risks with any energy storage technology is the possibility of uncontrolled energy release. In the context of lithium batteries, that means explosions or fires triggered by short circuits.
While rare, shorts can occur if battery terminals touch conductive materials resulting in rapid heating and thermal runaway.
To prevent accidental shorts, properly store lithium cells, packs, or modules in non-conductive racks or shelving. Many battery storage cabinets and containers also have dedicated cutout slots or dividers to keep each unit safely separated.
If stacking battery units, use non-conductive spacers between layers and avoid placing any metal objects or loose hardware nearby that could fall onto the terminals.
Keep a Battery Fire Extinguisher Handy
Speaking of lithium battery fires, having the right type of suppression equipment on hand, just in case, is never a bad idea.
While major battery storage facilities are required to install automated sprinkler systems, even a single consumer-grade lithium pack contains enough stored energy to fuel a very hot and persistent blaze.
Carbon dioxide, dry chemical, and even water extinguishers can extinguish lithium battery surface fires under certain conditions if applied quickly and thoroughly enough.
However, the most recommended type of suppressant for lithium energy fires is a Class D extinguisher or Lith-X powder which emits a graphite-based thermal absorbing powder.
So keep an appropriate fire extinguisher near any substantial lithium energy storage setup (just avoid actually spraying batteries preemptively).
And perhaps even more importantly, make sure everyone in the household knows how to properly operate installed extinguishers in case of emergency.
Carefully Inspect Before Returning to Service
Any batteries that have remained unused in storage for more than a few months should get a thorough inspection prior to going back into service. Here’s a checklist of what to examine:
- Bloating or deformation suggests gassing and imminent failure risk from swelling cells. Safely discharge and dispose of.
- Corrosion around terminals hints at humidity exposure degrading insulating seals. Clean gently or replace pack.
- White powder deposits flag overheating and material breakdown internally within cells. Retire battery.
- Low voltage under load indicates diminished pack capacity, though still safe if above minimum cut-off threshold according to product specs.
Closely monitoring storage conditions, maintaining moderate temperatures year-round, keeping batteries 50% charged, and preventing accidental shorts or impacts goes a long way in extending lithium battery lifespan and staying hazard-free. But even with great care, lithium cells don’t last forever.
Carefully inspect batteries that have been stored or unused for over 6 months before charging or installation to catch any damage or degradation issues ahead of time.
The Future of Safer Lithium Batteries
As global lithium battery installations continue rising each year, particularly massive grid storage arrays, so too has the pressure to develop intrinsically safer battery chemistries.
The inherent risk with lithium cells comes from the flammable electrolytes required to enable conductivity between the positive and negative electrodes.
Next generation lithium cells may replace this combustible electrolyte liquid with safer polymer materials or even solid-state ceramics which can virtually eliminate many failure risks altogether.
Several promising technologies currently under commercial development could reach market over the next 5 years promising better resilience against spikes in temperature and current.
Of course any new battery chemistry ushers in its own unique handling considerations which manufacturers intend to clearly communicate as new formats emerge.
Though still firmly established as the dominant lightweight rechargeable battery for the foreseeable future, ongoing lithium innovation may soon simplify storage and charging requirements.
But in the meantime following these best practices allows conveniently storing lithium batteries while optimizing lifespan, performance, and most critically of all, safety.
So stay tuned for safer batteries as this pivotal technology continues rapidly evolving!
