Designing the Perfect Battery

The first “battery” dates back thousands of years to 250 BC, when a primitive structure designed by the Parthians used copper and iron in a clay jar to electroplate silver, but it wasn’t until much later that we were able to control the production of electricity.

In 1800, Alessandro Volta stacked discs of copper and zinc, separated with cloth soaked in salt water, and managed to produce a continuous current, creating what is widely considered to be the first true battery.

Since then, scientists have been on a mission to develop the perfect battery; investigating new chemistries, structures and charging methodologies to maximize both performance and safety.

What is it that makes a battery “good”? It seems obvious – it needs to be safe, cheap, efficient, small enough to be used in handheld devices, powerful, rapidly charging and with a long lifetime.

But looking deeper into battery chemistries, it’s clear that the design and manufacturing processes require extensive optimization to balance the huge power requirements of modern technology with the miniaturized structures needed to match the size, structure and design requirements of devices such as electric scooters and mobile phones.

In this listicle, we explore five key factors that must be considered when developing new batteries, which will enable us to design bigger, better and safer batteries.

1. Longer lifecycles for everyday use

During its lifetime, a battery will undergo hundreds, if not thousands, of charge/discharge cycles, with some users potentially not following guidance and leaving devices on charge for extended periods of time or recharging before charge has run out. Over time, the battery loses its ability to return to its original capacity, and once its total capacity declines to ~80% of the original capacity, its life is considered to be over.

Lithium-ion (Li-ion) batteries have a longer lifecycle than other battery chemistries, with up to 2,000 charge/discharge cycles before losing capacity, which is critical in reducing the environmental impact of electronic devices, and positions Li-ion batteries as the preferred choice.

Accurately predicting battery life requires intricate knowledge of battery chemistry and behavior under a range of conditions. There are modeling tools available that support the prediction of aging in batteries, but these come with limitations, requiring a deep understanding of all parameters.

Combining reaction calorimetry, which determines the heat generation profile and performance characteristics, with safety testing using adiabatic calorimetry can provide a complete picture on battery thermal stability, including its life cycle.

2. High Coulombic efficiency to maximize performance

Coulombic efficiency is the ratio between the amount of energy released during the operation of the battery compared to the energy accumulated in the charged battery. It is often considered to be the most important consideration in understanding the performance of a battery.

Li-ion batteries are generally some of the most efficient at around 99%, with energy only lost as a result of internal resistance. As such, Li-ion batteries are considered to be the gold standard in the chemistry industry, offering a high energy efficiency, while also keeping within the critical parameters.

3. Safety precautions to minimize risk of explosions

The greatest risk in batteries is that of a thermal runaway. During battery operation, heat can accumulate, resulting in a temperature increase. If dissipation methods are not able to efficiently remove this heat, high temperatures can result in the acceleration of internal chemical reactions, including decompositions, resulting in more heat, and triggering a positive feedback loop known as a thermal runaway. Additionally, the accompanying build up of flammable gases can lead to an explosion.

These thermal runaways can be avoided, or at least mitigated, with the right tools. During design and manufacturing processes, researchers must evaluate the energy released by the battery under both standard and extreme use conditions, enabling the implementation of suitable thermal management systems.

4. Increasing energy density to reduce size

Energy density refers to the amount of energy a battery can store per unit of mass and is therefore crucial when designing smaller batteries that are equally as powerful as their giant counterparts. For example, increasing energy density in electric vehicles could allow users to travel further without increasing the size of the battery, saving space, weight and manufacturing costs.

However, when increasing the energy density of a device, we are also increasing the dangers associated with failure – increased volumes of electrolyte and power can lead to much larger, more damaging thermal runaways.

Research into novel battery chemistries such as lithium iron phosphate or lithium titanate, both of which have a lower energy density and higher temperature tolerance than Li-ion batteries, is enabling the development of smaller batteries for use in EVs.

5. Ensuring high performance at all temperatures

The impact of external temperatures on battery performance should not be underestimated; in moderation, higher temperatures are known to increase performance, while lower temperatures have a negative impact.

However, outside of standard or optimal working temperatures, there can be drastic impacts on battery performance. Extreme temperatures can accelerate the degradation of battery components, further increasing the risk of thermal runaways.

Adiabatic calorimetry plays a crucial part in determining the safe limits of operation for a battery, measuring the energy produced during a reaction, and allowing manufacturers to safely expand the optimum temperature zones of operation.

Destructive testing can also be used to identify the temperature at which a battery will descend into an uncontrolled thermal runaway, and also determines the maximum temperature the battery will reach in the event it does catch fire, facilitating the incorporation of suitable protective measures.

Are we ready for the perfect battery?

By carefully balancing these key parameters, we can continue to advance battery performance and safety, enabling the development of more powerful, compact devices for use in mobile devices, electric vehicles and energy storage facilities.

Most important of these is increasing energy density – the huge demand for miniaturized batteries in both industry and everyday life brings with it a much higher risk of thermal runaway, and as such requires appropriate thermal management strategies.

With more investment and research in the space, we will continue to expand the realms of possibility for energy storage and use as we continue in our mission to design the perfect battery.