Developers often moan that battery technology improvements are not keeping pace with product needs, but there’s a good reason for that

By Richard Quinnell, editor-in-chief

Instances of
batteries catching fire or even exploding have highlighted a serious design
challenge facing creators of mobile devices, electric vehicles, drones, and the
like. Battery technology falls far short of the ideal that developers desire. A
great deal of research has been and is being done toward creating the ideal
battery, but breakthroughs remain elusive. One reason for the situation is that
there are many different, and conflicting, goals to optimize.

One of the key
characteristics that developers seek is a high energy density. But even this
basic quantity remains a bit elusive. Depending on the application, the term
may refer to total energy in terms of deliverable watt hours per unit volume,
per unit weight, or both. Lead-acid batteries, for instance, can store a lot of
energy but are relatively heavy, which creates a problem when using them to
power electric vehicles due to the need to carry all of that weight around. The
ideal battery, of course, would be both small and lightweight while offering substantial
reserves of energy.

Image source: Pixabay.

A second key
question is if the battery can be recharged. Not all battery chemistry is a
reversible reaction. Alkaline and silver-oxide batteries, for instance, cannot
be reliably recharged, whereas lithium-ion and lead-acid batteries can be. The
ability to recharge a battery is highly desirable in many applications, though,
as it can eliminate the need to remove and replace batteries that become
exhausted.

There are other
desirable characteristics beyond energy density to consider in a battery
design as well. 

What is the
battery’s terminal voltage at full charge, and how does it change as it
discharges? That can make a difference in how many battery cells must be
connected in series or whether regulators are needed to provide an appropriate
voltage to run electronics reliably throughout the battery’s discharge curve.

How much current
can the battery reliably source? Pull energy out of a battery too quickly and
it heats up due to its internal resistance, which both wastes capacity and
creates a fire or explosion hazard. But some designs, such as wireless IoT
devices that communicate in bursts, need only a trickle of current sometimes
and a surge of current at other times.

The flip side of
that question is how quickly a battery can be recharged. This only applies to
batteries with reversible chemistry, of course, but is essentially the same heating
problem as drawing current out. Too quick a recharge can permanently damage the
battery. A related recharge question is how many times the chemistry can be
reliably reversed. Rechargeable batteries will “wear out,” storing less and
less energy over time.

Then there are
the secondary characteristics to consider. Are poisonous, corrosive, reactive,
or rare materials involved? Does the battery have a liquid component such that
there is a leakage concern? What is the battery’s self-discharge rate? How do
any of its primary specifications (voltage, capacity) change with temperature? Will
it even operate at all at high or low temperature extremes? Can the battery be
fabricated to occupy an odd shape or to be flexible?

Abuse-Tolerant_Li-ion_Battery_Fig-2

This abuse-tolerant battery will still function even when cut in
half. Image source: U of MD.

There is also the
question of whether or not a battery is the right approach in the first place.
Much research is going into the creation of fuel cells as an alternative to
batteries. These are chemical reactions that produce electricity while
irreversibly consuming their “fuels.” The classic example is the hydrogen fuel
cell used in manned spacecraft. It combines hydrogen and oxygen to produce
water as the byproduct of generating electrical current.

This multitude of
questions and considerations has driven battery developers in as many different
research directions, as the below survey of recent battery articles from across
the AspenCore network shows. There are promising results for batteries that
optimize for one or more of these characteristics. As of yet, however, no one
has found a result that addresses them all. Depending on your application’s
need, then, you may or may not see hope in these development efforts. But the
search will undoubtedly continue for the ideal battery, and in the meantime, there are some techniques offered in the articles below that you can apply to
mitigate drawbacks in current battery technology.

World’s
first rechargeable proton battery may be an eco-friendly alternative to Li-ion
— Researchers
believe that the proton battery has the potential to displace Li-ion batteries.

Advanced
battery packages empower next-generation systems
— Engineers
have more and more choices when designing and specifying their battery packs.

How
saltwater batteries can be used for safe, clean energy storage

Saltwater batteries hold powerful advantages in applications in which size and
weight are less important factors.

Will
fuel cells replace batteries in cost efficiency and portable applications?

— Fuel-cell maker MyFC predicts that fuel cells
will surpass batteries in energy density and cost efficiency in a few years.

Energy-storage
options: abundant alternatives and tricky tradeoffs

A look at batteries for grid-level energy storage.

Comparing
common battery types for mobile devices

A look at lithium-ion, lithium-polymer, nickel-cadmium, nickel-metal hydride,
and other battery technologies.

Researchers
Print Stretchable Battery to Light Wearables
— Researchers
recently demonstrated a newly formulated zinc-silver-oxide rechargeable battery
technology that can be printed on fabric.

Scientists
discover new battery material for super-fast charging and stable operation
— Researchers
are developing anodes made from lithium titanate hydrate, a fast-charging
water-bearing compound.

Solid-State Batteries Aim to Top Li-ion — Solid-state batteries could allow individual chips to be self-powered.

Startup
aims to bring sodium-ion batteries to mass production by 2020

French company Tiamat is dedicated to the development and production of
alternatives to lithium-ion batteries.

New
Li-ion battery design continues working after it’s cut in half or dunked in
seawater
— Research results in an abuse-tolerant
battery design.

Keeping
it safe: the lithium-ion battery

A look at the methods used to help make Li-ion batteries safer.

Nanodiamonds
Found to Prevent Lithium Battery Fires
— Scientists
think they have a solution to what caused Note 7 battery fires.

Testing
IoT Devices: Battery Life
— A
TechOnLine webinar from Rhode & Schwarz on effective ways to test and
analyze battery life consumption by IoT devices.