Battery Blues

To date primary cell batteries have been the most popular way to power low cost devices. However, they have limitations that have required the battery industry to look at more innovative ways of powering devices. One of the key market areas that are helping to drive small battery innovation forward is the Internet of Things (IoT).

Current battery trends in rechargeable cells require batteries to have a lower discharge rate for several reasons; to increase the length of time the charge can be held but also the ability to be trickle charged by the range of energy harvesting chargers now available.  Energy harvesting is an exciting prospect to obtain energy from the environment. This can be from solar, heat or from the device itself, through vibration. Conversely, often fast discharge functionality is also needed to support the very high currents for pulse type communications typically found in older cellular systems.

Industrial IoT (IIoT) brings it with several additional challenges. The battery technology needs to be low cost, a small physical footprint and able to operate across a range of environments. Industrial rated batteries are required operate over wide temperature ranges both high and low and typical electronics specs for the industrial space quote temperature ranges of -40°C up to 100°C or more. So the chosen battery technology needs support these ranges. But industrial locations also often have high humidity, a variety of vibrations and some are in total darkness, if they are unmanned. To add more complications, Lithium metal primary batteries are classed as dangerous goods and are restricted on flights as there can be a risk of becoming flammable in some circumstances.

For rechargeables, Lithium-ion batteries have been the main workhorse of battery technologies over recent years – however they are now experiencing additional pressures from external influences. As the number of battery powered devices increases, the issue of disposal of the batteries is becoming more of a concern. It has been recognised the current issues of disposal around plastics will soon be followed on by safe battery disposal as a key concern as more devices such as mobile phones and cars continue to increase their battery usage. Many products have benefitted from the advancement in smaller, lower-power battery technologies, as seen in the mobile phone space, but the trend here is for larger batteries to support the increased range of activities, whilst being able to maintain a day long charge.

The current poor environmental footprint of batteries, with respect to the levels of toxic metals and chemicals, is becoming more of a focus for EU regulations with more emphasis on safe disposal. More responsibility is being put back onto the battery manufacturers who are having to finance the cost of collecting, treating and recycling all collected batteries, which will ultimately put additional pricing costs on the batteries themselves. The cost of the underlying metals used are also increasing due to the rising demand from electrical and hybrid cars. A very worrying trend is the cost of Lithium itself is expected to increase x4 in the next 5 years according to the EU.

As these increasing pressures are being applied to Lithium based batteries, more companies are looking at how they can either reduce the size, or in some cases remove the battery completely from their small devices. Harvesting energy is key to turning this into a reality. There are a wide range of energy harvesting options including thermal, solar and vibration. All these aspects could be leveraged in an industrial location as more of an energy source than a hindrance. 8power is looking at how tailored solutions can be incorporated into sensing devices to maximise the power that can be harvested from the environment. Some instances such as for outside plant equipment monitoring, a small photovoltaic cell can power a wireless sensor; whereas a larger piece of rotating plant equipment can create enough vibration to power more sophisticated and much higher power systems.

There is an abundance of energy in the environment and we need to have solutions that take advantage of this. At 8power we believe that our energy harvesting eliminates the need for battery replacement and recharging. This not only makes great economic sense, it also helps the environment by reducing the cycle of metal mining and disposal. It is a true “win-win”.