Around 85% of all lead produced goes into lead-acid batteries.
Despite having been in use for over 160 years, the lead-acid battery is nevertheless widely used and is still a growing market. While lithium-ion batteries are increasingly replacing traditional lead-ion batteries, in some applications there remains a need for the humble lead-acid battery.
The
end use of lead-acid batteries is dominated by use in the automotive and other
transportation (i.e. forklift trucks) industries. Each car battery contains
around 12kg of lead, and with an estimated 1.4bn cars currently in the world
that is over 16.8Mt of lead in circulation which will be able to be recycled in
the future, and, with the average lifecycle of a car battery is 3-4 years the
future is not too distant.
Uninterruptable
Power Source (UPS) applications is another large user of lead-acid batteries.
In systems such as back-up generators batteries spend most of their time idle.
When they are used the UPS must discharge its batteries very rapidly and at a
high current until the generators come online. When power is restored, the UPS
recharges the batteries, then enter another extended waiting period. Lead-acid
batteries are well suited to this type of intermittent use.

Recycling
Process
Almost
100% of material in an ULAB can be recycled and infinitely reused with no
degradation or loss of future performance. Schemes have also been implemented
to make it financially rewarding to recycle ULABs giving them an extremely high
recycling rate of over 90% in many countries.

The
recycling of lead acid batteries involves two main steps: breaking and
separation, and secondary lead refining.
The
first step of the recycling process is battery breaking, literally breaking
open the batteries in a hammermill and extracting and sorting the component
parts including lead paste, metallic plates and connectors, polypropylene and
other plastics, and acid electrolyte.
The
lead, in the form of lead metal and paste, from the breaking and separation
process, is refined in a secondary lead smelting process, that produces lead in
bullion form.
The
sulfuric acid can be converted to sodium sulphate which is commonly used in
fertilisers and laundry detergents and the plastic polypropylene container is
output as pellets for reuse in new battery containers and other plastic
products.
In
the recycling process there is less than 3% of the battery which is not able to
be recycled and is sent to the landfill.
Benefits
of Battery Recycling
Recycling
keeps more than 130 million lead-acid batteries out of landfills each year.
Approximately 80% of a lead-acid battery consists of recycled materials, which
include lead and plastic components. The major benefits of recycling ULABs
include; ensuring unsafe and environmentally damaging materials are properly
handled and do not enter the environment. Recovering expensive metals and materials which
also helps to ensure a consistent supply and helps to drive down the cost of
new batteries.
Risks/Hazards
Recycling
of ULABs is not only vital for supporting the future supply, but also for
environmental reasons. Lead is high toxic, there are currently no known levels
of lead exposure that are considered safe. If any lead enters the atmosphere it
can lead to huge consequences to both the environment and health leading to birth
defects, delayed development, neurological problems and even death.
Lead-acid
batteries are covered under the Basel Convention on the Control of
Transboundary Movements of Hazardous Wastes and Their Disposal is an
international treaty that was designed to reduce the movements
of hazardous waste between nations, and specifically to prevent
transfer of hazardous waste from developed to less developed
countries. The Convention entered into force in May 1992. This sets out guidelines
to improve recycling of old batteries and protect human health and the
environment.
Future
Recycling Growth
Lead-acid
batteries will play an essential part in the global transition to green energy
sources. With ambitious global targets to achieve the 2015 Paris Agreement of
limiting global warming to well below 2C, preferably to 1.5C, compared to
pre-industrial levels, new low carbon emitting and green energy solutions are
booming. With countries such as India, who are developing rapidly, having much
later net-zero targets than the rest of the world, lead usage is predicted to
continue to grow.
In
traditional internal combustion engine (ICE) vehicles lead-acid batteries are
used as a starting battery. The application is called starting, lighting, and
ignition (SLI). Although the growth of electric modes of transportation will
eventually result in fewer ICE vehicles, production of low-cost gasoline and
diesel-powered cars in places such as India and Asia will keep demand high for
decades to come.
In
electric vehicles (EVs) lithium-ion batteries are the batteries of choice to
power the traction motors, however, many continue to use lead-acid batteries to
power the microprocessors that start up the system, and, to operate lighting
and audio, and entertainment systems. The low voltage lead-acid battery is
typically kept charged using a DC to DC converter which converts the
high-voltage (typically 300-600V) from the lithium-ion battery pack to the
low-voltage (12V) that maintains the charge of the lead-acid battery.
In
intermittent renewables energy source like wind and solar an energy storage
system is required to make them effective. This is because of the need to store
the electricity when it is produced (i.e. when the wind is blowing or the sun
is shining) as the supply is not guaranteed. The low cost of lead-acid
batteries makes them a popular choice to store renewable energy for both
small-scale home use and grid-scale industrial use.
Lead-acid is
frequently used in off-grid applications such as isolated microgrids,
particularly where upfront costs can be a barrier. There is work being done to
replace these batteries with zinc-ion or lithium-ion but the low-cost and high
availability/reliability of lead-acid batteries mean they will still be used
for years to come.
