LITHIUM ION BATTERY
STORAGE & MAINTENANCE CHAR GING
The following applies to the storage/shelf life of Lithium Ion cells and batteries.
The storage temperature range for Lithium Ion cells and batteries is -20°C to +60°C (-4°F to 140°F).
The recommended storage temperature range is 0°C to 30°C (32°F to 86°F). At this storage temperature
range, the battery will require a maintenance charge within a nine (9) to twelve (12) month period. A
detailed maintenance charge schedule, based on storage temperature, is located at the end of this
white paper.
Lithium Ion rechargeable batteries should be stored at 50% to 60% state-of-charge (SOC).
The shelf life of a lithium ion cell/battery is a function of the self discharge, temperature, battery age and
state-of-charge (SOC) conditions imposed upon the cell/battery. As the storage temperature and SOC
increase, the resultant capacity upon discharge decreases and the impedance of the cell(s) increases.
The shelf life is almost cut in half by holding the cell/battery at 100% SOC at temperatures between 30C
and 60C as opposed to 50% SOC at the same temperature range. The effect is not as pronounced at
room temperature, with the shelf life roughly 75% at a 100% SOC condition as opposed to 50% at
elevated temperatures.
In other words, the shelf life would be approximately four months (at 100% SOC) to nine months (at 50%
SOC) at a storage temperature of -20°C to 30°C (-4°F to 86°F), provided that the cell/battery has been
operated under recommended charge, discharge and storage conditions. After that point, the cell/battery
would need a maintenance charge to return it back to its recommended original storage voltage (SOC).
We do not recommend float charging lithium ion batteries, since the current will eventually decay the
surface films on the electrode and electrolyte, shortening cycle life significantly. Float charging can harm
lithium ion chemistry and is not recommended. The recommended and preferred charging method for
rechargeable Lithium Ion batteries is a modified constant current / constant potential charger.
Please see Figure 1 below, showing independent testing performed by Motorola for the Lithium Ion
18650 cell. The Lithium Ion 18650 cell is the cell that is used by battery manufacturers for manufacture of
the rechargeable Land Warrior (PB-LW, PB-LWH & LI Series) and BB-2590/U (XX90 format) batteries
and other battery configurations.
The following data is what has been observed specific to the lithium ion 18650 cells used in the
rechargeable Land Warrior and BB-2590/U (XX90 format) batteries and other battery
configurations at an elevated storage temperature of 60°C (140°F).
% CAPACITY REMAINING
100% SOC
Storage Time
2 Wks.
1 Month
2 Months
3 Months
6 Months
9 Months
C/5 Rate
90%
87%
83%
80%
C Rate
90%
87%
83%
80%
50% SOC
C/5 Rate
98%
90%
88%
85%
80%
80%
C Rate
98%
90%
88%
83%
80%
80%
Creating Technology Solutions, LLC | P.O. Box 5827 | Titusville, FL 32783
Tel 321-418-3055 | Fax 321-418-3044 | www.crtes.com | CAGE Code: 6Y7W5
©2014 Creating Technology Solutions | All information subject to change without notice | April 2014 | Rev.00
The information contained herein is for reference only and does not constitute a warranty of performance
LITHIUM ION BATTERY
STORAGE & MAINTENANCE CHAR GING
Back-up / Storage testing: Moli 2.2Ah 18650: No charge Maintainence
30 C
45 C
60 C
Percent of initial capacity (%)
100.0
98.0
96.0
94.0
92.0
90.0
3.9
4.0
4.1
3.9
Storage time
4.0
4.1
3.9
Storage voltage (V)
4.0
4.1
(weeks)
Aft
er
Aft
0w
er
ee
Aft
2w
ks
er
ee
of
6w
ko
s to
ee
fs
rag
ks
tor
e
ag
of
e
sto
rag
e
Figure 1
High Temperature & High State-of Charge (SOC) Degradation Performance
Creating Technology Solutions, LLC | P.O. Box 5827 | Titusville, FL 32783
Tel 321-418-3055 | Fax 321-418-3044 | www.crtes.com | CAGE Code: 6Y7W5
©2014 Creating Technology Solutions | All information subject to change without notice | April 2014 | Rev.00
The information contained herein is for reference only and does not constitute a warranty of performance
LITHIUM ION BATTERY
STORAGE & MAINTENANCE CHAR GING
STORAGE MAINTENANCE RECHARGE SCHEDULE
WHEN STORED AT RECOMMENDED 50% to 60% STATE-OF-CHARGE (SOC)
Storage Temperature
Relative Humidity
-20°C to 30°C (-4°F to 86°F)
-20°C to 35°C (-4°F to 95°F)
-20°C to 40°C (-4°F to 104°F)
-20°C to 45°C (-4°F to 113°F)
-20°C to 50°C (-4°F to 122°F)
-20°C to 55°C (-4°F to 137°F)
-20°C to 60°C (-4°F to 140°F)
45% to 85%
45% to 85%
45% to 85%
45% to 85%
45% to 85%
45% to 85%
45% to 85%
Freshening Recharge
within 1 year
within 9 months
within 6 months
within 1 month
within 1 week
within 1 week
within 1 week
In Summary:
1. As storage temperature and stat-of-charge (SOC) increases, retained capacity decreases.
2. The lost capacity is due to degradation reactions in the cell that are accelerated by
temperature and consume lithium ions on the anode surface.
3. Recommended storage is at 50% to 60% state-of-charge (SOC) and 0°C to 30°C (32°F to
86°F).
4. Maintenance charge at a temperature range of 0° C to +45° C (32°F to +113°F).
5. Maintenance charge using a modified constant current / constant potential charger.
While considerable effort has been taken to accurately represent the information contained herein, Creating
Technology Solutions does not guarantee its accuracy or completeness and Creating Technology Solutions
disclaims any obligation to update such information. Creating Technology Solutions makes no
representations or warranties as to the completeness, adequacy or reliability of this information and shall
not be held liable for any lack of the foregoing. Furthermore, the information does not constitute legal
advice on battery storage and maintenance charging and should not be considered legal advice, nor
substitute for obtaining battery storage and maintenance charging advice directly from Creating Technology
Solutions engineers.
Creating Technology Solutions, LLC | P.O. Box 5827 | Titusville, FL 32783
Tel 321-418-3055 | Fax 321-418-3044 | www.crtes.com | CAGE Code: 6Y7W5
©2014 Creating Technology Solutions | All information subject to change without notice | April 2014 | Rev.00
The information contained herein is for reference only and does not constitute a warranty of performance
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