H a r s h E nv iro nm ents LiSOCL2
LiSOCL2
Li Metal Oxide
Li Metal Oxide
LiFeS2
LiMnO2
Primary Cell
Bobbin-type with Hybrid Layer Capacitor
Bobbin-type
Modified for high capacity
Modified for high power
Alkaline
Lithium Iron Disulfate
CR123A
Energy Density (Wh/1)
1,420
1,420
370
Power
Very High
Low
Very High
185
600
650
650
Very High
Low
High
Voltage
3.6 to 3.9 V
3.6 V
Moderate
4.1 V
4.1 V
1.5 V
1.5 V
Pulse Amplitude
Excellent
3.0 V
Small
High
Very High
Low
Moderate
Passivation
Moderate
None
High
Very Low
None
N/A
Fair
Moderate
Performance at Elevated Temp.
Excellent
Fair
Excellent
Excellent
Low
Moderate
Fair
Performance at
Excellent
Fair
Moderate
Excellent
Low
Moderate
Poor
Operating life
Excellent
Excellent
Excellent
Excellent
Moderate
Moderate
Fair
Self-Discharge Rate
Very Low
Very Low
Very Low
Very Low
Very High
Moderate
High
-55°C to 85°C, can be extended to 105°C for a short time
-80°C to 125°C
-45°C to 85°C
-45°C to 85°C
-0°C to 60°C
-20°C to 60°C
0°C to 60°C
Low Temp.
Operating Temp.
Table 1: Each battery chemistry offers unique features, including varying temperature ranges. These chemistries include alkaline, iron disulfate (LiFeS2), lithium manganese dioxide (LiMNO2), and lithium thionyl chloride (LiSOCl2) batteries.
Designing a wireless device to be as small as possible without compromising performance or system functionality is always a challenge. Intelligent power management approaches are required to use battery power efficiently and cost effectively, especially in extreme environments.
Start by thinking small A common practice is to specify batteries that are overly large or that deliver unneeded capacity to achieve the required battery operating life. But selecting an oversized battery carries hidden costs, including the expense of transporting batteries to remote, hard-to-access locations, where the labor and logistical expenses can be high. Increasingly restrictive UN and IATA shipping regulations can further add to these transportation costs. A compact, lightweight, long-life power supply can offer other tangible benefits. For example, scientists conducting experiments to monitor the changing size and position of ice flows in the Arctic Ocean want the device to be as small and lightweight as possible in order to be deployed by helicopter. Conversely, a utility linemen carrying line fault sensors up and down utility poles seeks a compact, lightweight solution that reduces fatigue. Of course, specifying an undersized battery to achieve product miniaturization goals could result in excessive battery replacements throughout the life of the device.
Oceantronics’ hybrid lithium pack provides the same operating life with smaller size for use in GPS/ice buoys. The original battery pack (left) used 380 alkaline D cells (54 kg). The new battery pack (right) uses 32 lithium thionyl chloride D cells and for hybrid layered capacitors (3.2 kg). 84
DESIGN WORLD
Harsh Environments 10-16_Vs6.LL.indd 84
October 2016
Extreme temperatures can impact battery performance Many primary battery chemistries are available, each offering unique performance features, including varying temperature ranges. These chemistries include alkaline, iron disulfate (LiFeS2), lithium manganese dioxide (LiMNO2), and lithium thionyl chloride (LiSOCl2) batteries (see Table 1). Exposure to extreme temperatures reduces both battery
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10/7/16 2:02 PM