WP-72-08 Datasheet, PDF (5/12 Pages) Cymbet Corporation – The 8 Key Competitive Advantages of Solid State Batteries

Executive Briefing
Avoiding an Energy Storage Crisis
They also create a liability risk. Two recent studies published in
Pediatrics, using different sets of data, both showed a rise in the
rate of serious poisonings from battery ingestion among children
over the last 25 years. This increase corresponded to the growing
use of lithium ion coin cell batteries in consumer electronics, with
the most dramatic increase coming since the introduction of
larger, more powerful 20-millimeter coin cells.^{xiii, xiv}
Rechargeable conventional batteries are also limited by low
charge-cycle life. They typically need to be replaced several
times over the life of a product. This increases customer
maintenance costs, lowers reliability, and makes conventional
batteries unsuitable for zero-maintenance applications, such as
remote monitoring sensors that employ energy harvesting
techniques.
Drawbacks of Supercapacitors
• High self-discharge rate
• Slow charging
• Spark hazard
• Output voltage proportional to
charge
• Capacity adversely affected by
temperature, voltage and age
• Generally ill-suited to reflow
solder assembly
Chemical batteries and
supercapacitors are becoming
obsolete for many applications
in the face of continued
miniaturization, integration and
sophistication of new electronics
products, as well as more
stringent customer demands.
Supercapacitors have a different set of drawbacks.
Among these drawbacks are high self-discharge and spark
hazard. Very low internal resistance results in self-discharge on
the order of 10 to 20% per day, and extremely rapid discharge
(sparking) if shorted. Power systems employing supercapacitors
end up being over-designed to compensate for losses and for
safety, resulting in a larger device footprint and added cost.
The high self-discharge rate also makes supercapacitors a poor
component choice when long-term energy storage is required.
Another drawback: supercapacitor output voltage is linearly
proportional to charge (i.e., voltage decays with discharge). For
example, a 3.3V supercapacitor delivers 3.3V when fully
charged, but only 1.65V when charged to 50% capacity. That's
well below the level at which many devices will operate. As a
result, a boost circuit on the backup power rail is often needed,
which adds to circuit complexity, device volume and cost.
Yet another limitation of supercapacitors is that their capacity is
usually degraded by exposure to high temperatures, making
them generally ill-suited for reflow solder assembly. Reflow
tolerant supercapacitors can cost as up to twice as much as
those not rated to reflow temperatures. Non-rated supercaps
require SMT sockets and hand soldering, which adds to material
and labor costs and reduces product life and reliability.
In short, chemical batteries and supercapacitors are becoming
obsolete for many applications in the face of continued
miniaturization, integration and sophistication of new
electronics products, as well as more stringent customer
demands.
©2013 Cymbet Corporation
WP-72-08
www.cymbet.com
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