Our lexicons list weird and wonderful batteries, but as with animal species, not all become house pets. A battery has stringent requirements. No less than eight requirements must be met to call a battery a battery. (See BU-104c: The Octagon Battery) Table 1 summarizes the less common batteries that serve various niche markets.
Chemistry |
Sodium-sulfur; Sodium-nickel-chloride (ZEBRA) |
Zinc-air |
Silver-zinc; |
Reusable Alkaline |
Type |
Molten-salt (Na) and sulfur (S). Economical with larger sizes, (Symbol NaS) |
Mainly primary; shares similarity with fuel cell |
Silver-zinc is rechargeable; silver-oxide is primary |
Disposable alkaline made reusable at a similar cost to regular types |
Voltage per cell |
2.58V |
1.40–1.65V |
1.60V |
1.50V |
Specific Energy |
90–120Wh/kg |
300–400Wh/kg |
250Wh/kg |
200Wh/kg, less with each subsequent recharge |
Activation |
Operate at |
Removal of seal enables airflow |
Instant |
Instant |
Charging |
Overnight charge |
Charging by replacement of zinc electrodes |
Similar to Li-ion |
Voltage limiting |
Discharging |
High power burst |
Low load |
Similar to Li-ion |
Low load (200–400mA) |
Cycle life |
3,000 cycles; |
Once activated, battery is being consumed |
Short cycle life; |
50, depending on DoD. Recharge often |
Maintenance |
Keep battery hot |
Only activate when needed |
Keep inventory low |
Do not discharge too low |
Failure modes |
Electrical shorts due to corrosion |
Sensitive to cold heat, humidity and air pollution |
Zinc electrode and separator decay; cycling causes dendrite formation |
50% capacity drop with 2nd charge; rising internal resistance |
Packaging |
Large systems of 10kWh and higher |
Mostly small sizes |
Button cells (silver-zinc) |
AA, AAA, C, D, 9V |
History |
Conceived by Germans in World War II; NaS gained new interest in 1970s |
“Breathing” discovered by Leclanché in 1878, offered to buyers in 1932 |
Spacecraft use because of high capacity. (Now replaced by Li-ion) |
Introduced in 1992, alternate to disposables. Leak-proof |
Applications |
Primary: One-shot missiles; Secondary: UPS, load- leveling, EV (Think City), delivery vans |
Hearing aids; large units for railway signaling, mines safety lamps |
Primary: Watches, memory backup; Secondary: Aerospace, missiles, military, TV cameras |
Flashlights, toys, entertainment devices |
Comments |
Heating consumes 14% of battery energy per day |
High capacity, low cost but only one-time use |
New designs show capacity gain over Li-ion: expensive raw material |
Regular alkaline should not be charged; danger of leakage, gas, explosion |
Detailed information is on BU-211: Alternate Battery Systems. All readings are estimated and may vary with different versions and newer developments.
Table 2 touches on semi-batteries. They are listed because of similarities with the electrochemical reaction of a real battery. What was once a unique device standing on its own is now merging with the battery, and the supercapacitor is such an example. The fuel cell has similarities also in that it is a battery in reverse. Overcharging a battery turns water into hydrogens and oxygen (gassing); the fuel cell produces electricity and water by combining hydrogens and oxygen.
Chemistry |
Supercapacitor |
Flow Battery |
Fuel Cell |
Type |
Double-layer capacitor. Stores energy by static charge as opposed to electrochemical reaction |
Rechargeable; pump operated, electrolyte stored in tank |
Combining hydrogen and oxygen produces electricity |
Voltage per cell |
Limited at 2.30–2.75V |
1.15–1.55V |
0.6–0.8V |
Specific Energy |
5Wh/kg (typical) |
40Wh/kg |
40Wh/kg |
Activation |
Instant |
sluggish ramp-up |
sluggish ramp-up |
Charging |
1–10s; simple charging, current stops when full |
Overnight charge |
Hydrogen feed through tank |
Discharging |
Very high power |
Low load current |
Low load current |
Cycle life |
1 million; 10–15 years |
10,000 cycles; 20 years. |
2,000–4,000h; stationary up to 40,000 hours |
Maintenance |
Low maintenance |
High |
High |
Failure modes |
Exceeding voltage limits lowers service life |
High corrosion. Vanadium keeps corrosion under control |
Stack damages by freezing and heat; capacity fade by cycling. |
Packaging |
Mostly in cylindrical formats |
Large systems; 20kWh and up |
Large, also portable |
Environment |
Broad temperature range. Non-toxic. |
Functions more like a refinery than a battery |
Must have correct moisture content. Cannot freeze. |
History |
GE experimented in 1956; Standard Oil discovered double layer in 1966; NEC commercialized it in 1978 |
First patent in 1954. Current types patented in 1986 |
William Grove, developed in 1839; space program 1960s |
Applications |
Memory backup, generator start, large MW systems. In competition with flywheel |
Large energy storage system; economical with large size |
Forklift, EV, UPS, portable usage in military |
Comments |
Expensive per Wh. Some argue to spend the money on a larger battery |
Capacity set by tank size; can be enlarged if so needed |
Clean but expensive; poor power band |
Readings are estimated and may vary with different versions and newer developments. All readings are estimated average at time of publication. Detailed information is on:
Comments
Looking for comments from the previous website?
Comments from the previous website are not compatible with our new commenting system but we have preserved them so our users can still reference and make use the information in them.