Are You Storing Lithium Batteries Correctly? 5 Best Practices for Battery Life and Safety

By Michael Adkins, Global OEM Sales Director

Lithium-ion batteries are used across industrial equipment, robotics, medical devices, portable electronics, energy storage systems, and other battery-powered products. Their high energy density, rechargeability, and power capability make lithium-ion technology an effective solution for a wide range of OEM applications.

But battery performance does not depend solely on how a battery is used.

How a lithium-ion battery is stored can have a significant impact on its capacity, service life, reliability, and safety.

For OEMs and organizations managing finished products, replacement batteries, service inventory, or spare battery packs, storage conditions should be treated as part of the battery lifecycle, not only a warehouse consideration.

State of Charge (SOC), temperature, humidity, storage duration, physical handling, and inventory management can all influence battery condition during storage.

Here are five important practices organizations should consider when developing a lithium-ion battery storage program.

1. Store Lithium-Ion Batteries at an Appropriate State of Charge

For many lithium-ion battery systems, long-term storage at a partial State of Charge is preferable to extended storage at either 100% SOC or a deeply discharged state.

A commonly used storage range for many lithium-ion systems is approximately 30% to 50% SOC, although the appropriate target should always be based on the recommendations for the specific cells and battery system.

Why does storage SOC matter?

Lithium-ion cells continue to age even when they are not being cycled. This is known as calendar aging.

Extended storage at a high State of Charge can accelerate degradation mechanisms within lithium-ion cells. Elevated cell voltage can increase electrochemical stress and contribute to long-term capacity loss and increases in internal resistance.

The opposite extreme can also create problems.

If a battery is stored at a very low SOC, normal self-discharge and the quiescent current consumed by battery electronics can eventually drive cell voltage below acceptable limits. Depending on the battery design, this may result in excessive discharge, BMS protection activation, or a battery that cannot be recovered through normal charging.

Battery storage best practice

Establish a defined storage SOC based on:

• Cell chemistry

• Cell manufacturer's recommendations

• Battery pack design

• BMS quiescent current

• Expected storage duration

• Storage temperature

• Operational readiness requirements

For many applications, maintaining a moderate SOC provides a practical balance between minimizing calendar aging and maintaining sufficient energy reserve to prevent excessive discharge during storage.

2. Control Battery Storage Temperature

Temperature is one of the most important variables affecting lithium-ion battery aging.

Chemical reactions responsible for cell degradation generally accelerate as temperature increases. When elevated temperature is combined with high SOC, calendar aging can become even more significant.

For many lithium-ion batteries, a moderate room-temperature environment—often approximately 10°C to 25°C (50°F to 77°F)—is preferable for extended storage. However, acceptable and recommended storage temperatures should always be verified against the specifications for the particular battery system.

Organizations should avoid prolonged exposure to conditions such as:

• Direct sunlight

• Hot vehicles

• Unconditioned shipping containers

• Areas near heat-producing equipment

• Warehouses experiencing prolonged temperature extremes

Why temperature control matters to OEMs

Storage-related degradation may not become apparent until the battery reaches the customer.

A battery can leave inventory with less usable capacity or increased internal resistance even though it has experienced few or no charge/discharge cycles.

That can translate into:

Reduced runtime → degraded product performance → premature replacement → warranty exposure → increased lifecycle cost

For organizations maintaining significant battery inventories, environmental control can therefore be both a reliability measure and a cost-control strategy.

3. Keep Batteries Dry and Control Humidity

Battery storage environments should protect batteries from water, condensation, and excessive humidity.

Moisture exposure can contribute to:

• Terminal corrosion

• Connector degradation

• Damage to battery electronics

• Contamination of electrical interfaces

• Reduced insulation performance

• Long-term reliability problems

Condensation deserves particular attention when batteries are moved between environments with substantially different temperatures.

A cold battery moved into a warm, humid environment may experience condensation on exposed surfaces or electrical connections.

Best practices for dry battery storage

Organizations should consider:

• Maintaining a controlled indoor storage environment

• Protecting batteries from direct water exposure

• Avoiding areas susceptible to condensation

• Using appropriate protective packaging

• Keeping electrical contacts clean and protected

• Following battery-specific humidity and environmental requirements

For custom OEM battery packs, enclosure sealing and ingress protection should also be considered during the original mechanical design process when the application requires environmental protection.

4. Protect Batteries from Physical Damage

Lithium-ion batteries should be handled and stored in a manner that minimizes the risk of mechanical damage.

Potential hazards include:

• Crushing

• Puncture

• Dropping or impact

• Excessive vibration

• Improper stacking

• Connector damage

• Enclosure deformation

Mechanical damage can affect cells, interconnects, wiring, BMS electronics, insulation, or the battery enclosure.

More importantly, significant cell damage can create internal defects that may not always be immediately visible.

Battery handling best practices

Stored batteries should be placed in packaging or fixtures designed to prevent movement, impact, short circuits, and excessive loading.

Heavy products should not be stacked on battery packs unless the packaging and battery design are specifically intended to support those loads.

Terminals and exposed electrical contacts should also be protected against accidental contact with conductive materials.

Battery storage procedures should therefore address electrical protection and mechanical protection, not simply warehouse temperature.

5. Monitor Batteries During Long-Term Storage

A battery placed into storage should not necessarily be assumed to remain in the same electrical condition indefinitely.

Lithium-ion cells naturally self-discharge, while the battery's BMS and other electronics may continue to consume a small amount of current even when the battery is not actively powering equipment.

Over an extended storage period, this can gradually reduce SOC.

The rate depends on factors including:

• Cell chemistry

• Initial SOC

• Battery temperature

• BMS architecture

• Electronics quiescent current

• Battery age

• Storage duration

Organizations maintaining long-term inventory should establish an inspection schedule appropriate for their battery system rather than relying on a universal interval.

Periodic checks may include:

• Pack voltage

• State of Charge

• Physical condition

• Connector and terminal condition

• BMS status

• Date placed into storage

• Lot or serial number

• Storage temperature history, where applicable

If SOC approaches the manufacturer's recommended minimum storage level, the battery may require maintenance charging according to the approved charging procedure.

Use FIFO Battery Inventory Management

Battery inventory should generally be managed using First In, First Out (FIFO) principles where practical.

FIFO helps prevent older battery inventory from remaining in storage while newer products are repeatedly shipped first.

For organizations managing large quantities of batteries, useful inventory records can include:

Manufacturing date → Receipt date → Initial SOC → Inspection history → Recharge history → Shipment date

This creates greater visibility into the actual age and storage history of battery inventory and can improve traceability when investigating field-performance issues.

Lithium Battery Storage Guidelines by Duration

Rather than applying the same inspection interval to every battery, organizations should establish requirements based on battery design, storage conditions, and expected duration.

Short-Term Storage: Maintain within manufacturer-approved SOC, temperature, and environmental limits. Protect terminals and battery enclosure from damage.

3–6 Months: Verify that storage conditions remain within specification and consider SOC/voltage verification based on battery self-discharge and BMS consumption.

6–12 Months: Establish periodic voltage/SOC and physical-condition inspections. Recharge according to the manufacturer's approved procedure when necessary.

1+ Years: Use a documented long-term storage program incorporating SOC monitoring, environmental controls, physical inspection, inventory rotation, and traceability.

Emergency/Reserve Batteries: Establish a maintenance schedule that balances storage-life optimization with the required readiness level for the application.

Engineering note: Storage SOC, temperature limits, inspection frequency, and maintenance-charging requirements should ultimately be determined from the specifications of the battery cells and complete battery system.

5 Common Lithium Battery Storage Mistakes

1. Storing Batteries Fully Charged for Extended Periods

Keeping lithium-ion cells at elevated voltage for prolonged periods can accelerate calendar aging.

If immediate full capacity is not required, a lower storage SOC may improve long-term capacity retention.

2. Allowing Batteries to Remain Deeply Discharged

A battery stored near its lower voltage limit can continue to lose charge through cell self-discharge and electronic quiescent current.

Eventually, cell voltage may fall below acceptable limits.

3. Exposing Batteries to Excessive Heat

High storage temperatures can accelerate degradation, particularly when combined with high SOC.

Warehouse temperature should therefore be considered part of battery inventory management.

4. Ignoring Inventory Age

Lithium-ion batteries age with time as well as cycling.

A battery that has never been used is not necessarily equivalent to a newly manufactured battery if it has spent years in storage.

5. Storing Damaged Batteries with Normal Inventory

Suspect or damaged batteries should not simply be returned to regular inventory.

Organizations should have procedures for identifying, isolating, evaluating, and appropriately handling batteries exhibiting abnormal conditions.

When Should a Lithium Battery Be Removed from Service or Quarantined?

Battery packs exhibiting signs of physical or thermal damage should be handled according to the manufacturer's procedures and applicable workplace requirements.

Potential warning signs include:

• Swelling or deformation

• Cracked or damaged housing

• Damaged connectors

• Corrosion

• Leakage

• Unusual odor

• Evidence of overheating

• Discoloration or melting

• Abnormal BMS faults

• Known impact, crushing, or puncture damage

A suspect battery should not automatically be recharged or returned to service without appropriate evaluation.

Disposition, transportation, and recycling should follow applicable manufacturer guidance and regulatory requirements.

Battery Storage Should Be Part of the Quality System

For organizations maintaining substantial battery inventory, storage should not be viewed solely as a warehouse function.

It can be incorporated into the organization's broader quality and battery lifecycle management system.

A documented program can define:

• Approved storage SOC

• Temperature and humidity limits

• Inspection frequency

• Maintenance-charging criteria

• Battery identification and traceability

• FIFO procedures

• Handling requirements

• Damaged-battery quarantine procedures

• End-of-life and recycling processes

These controls help maintain consistency between the condition of a battery when it leaves manufacturing and the condition of that battery when it eventually enters service.

The Engineering Behind Better Battery Storage

Proper lithium-ion battery storage is a relatively straightforward operational practice, but its impact can extend across the product lifecycle.

For OEMs and organizations managing battery-powered products, three principles are particularly important:

1. Maintain an appropriate storage State of Charge.

Avoid unnecessary extended storage at either very high or very low SOC.

2. Control the storage environment.

Temperature, moisture, and physical protection can significantly influence long-term battery condition.

3. Monitor long-term inventory.

Track battery age, SOC, condition, and storage history rather than assuming unused batteries do not age.

The appropriate storage strategy ultimately depends on the cell chemistry, battery architecture, BMS design, application, and expected storage duration.

That is why battery storage should be considered during battery system development—not after the product reaches the warehouse.

Custom Lithium Battery Engineering from Apex Mobile Power

At Apex Mobile Power, battery performance is considered across the complete product lifecycle from cell selection and BMS development to mechanical design, thermal management, manufacturing, storage, and field operation.

For OEMs, that means developing a battery system around the requirements of the actual application rather than treating the battery as a standalone commodity.

Understanding how a battery will be charged, operated, transported, stored, and maintained allows engineering teams to make better decisions during the initial design process and support more predictable performance throughout the life of the product.

Apex Mobile Power – The Power Behind Your Brand.

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