Design Optimization Minimizes Battery Environmental Impact

For many of the essential green technologies, such as electric vehicles (EVs) and solar and wind power infrastructure, we rely on one vital component: batteries. But this comes at a cost to the earth, as raw materials must be mined.

Alternative storage methods, such as more effective solid-state batteries and gravity batteries, are being developed. But for the time being, many applications—especially EVs—rely on lithium batteries.

So how can we reduce the environmental impact of our use of batteries? With careful design and component selection, we can ensure our systems get the most out of the batteries they use—by both reducing power consumption and optimising the power design of our systems. This enables us to use smaller battery sizes, extend battery life, and deliver better performance for the end user while reducing the environmental impact.

This article will explore some of the options available which can help engineers to develop highly optimised designs that maximise their batteries' operational efficiency and lifespan.

Development Tools for Batteries

Choosing a battery may seem like a relatively simple task: Engineers simply work out the power required for a design and select the best component that balances size, weight, cost, and energy capacity.

However, engineers can use development tools to make this task easier and get the most out of the batteries they specify. Development tools enable engineers to boost the end solution's performance without increasing battery size or requiring excessive redesign.

They also enable engineers to reduce overall power consumption through real-world component consumption analysis, thus extending overall battery life and reducing power consumption.

One such tool is the Power Profiler Kit II (PPK2) from Nordic Semiconductor (Figure 1). The PPK2 gives hardware and software engineers a simple method for measuring the average and dynamic power consumption in embedded systems, therefore providing the ability to debug the power usage of their solution.

The PPK2 has a high dynamic input range, which enables accurate current consumption measurements over the entire range of typical embedded applications, from 200nA to 1A. It can measure low sleep currents, higher active currents, and short current peaks.

The PPK2 also provides eight digital inputs that can be used as a low-end logic analyser. This makes it simple to link the power consumption to blocks of code being executed. The PPK2 can be connected to any Nordic development kit or custom board as a standalone unit, with no additional kits or debuggers.

Another example of a battery development tool is the Qoitech Otii Arc Pro Energy Optimisation Tool, which includes both hardware and software to enable designers to get the most out of batteries.

The Otii Arc Pro combines a power profiler, DC energy analyser, power supply, digital multimeter, source measure unit, and power debugger. It can precisely measure voltage and current and calculate power and energy as well as sync with software output. This means that engineers and developers can easily see what drains the energy in their devices under test, allowing them to optimise battery life.

The Otii Arc Pro also enables designers to match their choice of battery to the demands of their system. While battery datasheets provide basic information on typical capacity, their real behaviour is more complex—with variations based on factors such as how the load draws power and operating temperature. For example, peaks of high current will reduce the life of a coin cell battery more quickly than sustained, lower current draw; this means that adding a capacitor in parallel can be a useful tactic.

Qoitech’s testing has shown that a lack of optimisation means that on average, between 30 and 50 percent of battery capacity is not used. With at least 15 billion batteries thrown away each year, reducing this wasted capacity would have a significant impact on the environment.

Power-Saving Technologies

As well as optimising their choice of the battery itself, engineers need to design their systems to use as little power as possible. By improving efficiency and reducing power usage, they can reduce the requirements placed on the system’s battery, thus enabling smaller, lighter batteries to be used and lowering overall costs. 

There are multiple technologies and materials that can help achieve this goal of lower power usage. One of the most important is silicon carbide (SiC), which can be used as an alternative to silicon in semiconductors. SiC devices are enabling increased performance in EVs and solar power generation, improving power efficiency to deliver more energy from the same resources. SiC transistors can switch higher currents than silicon MOSFETs and can operate at higher frequencies.

In recent years, SiC power semiconductors have become increasingly popular, with their advantages outweighing their higher cost compared to other technologies. As well as efficiency, they support higher power density, thus enabling smaller power systems to be created.

For example, Infineon Technologies CoolSiC™ MOSFETs enable power density to increase by a factor of 2.5 compared to silicon IGBT-based solutions. One such device, the IMYH200R100M1H 2000V SiC trench MOSFET (Figure 2), is suitable for applications such as string inverters, solar power optimisers, and EV charging. It is designed to deliver increased power density without sacrificing reliability, even under demanding high-voltage and switching frequency conditions.

Click image to enlarge

Figure 2: Infineon CoolSiC MOSFETs. (Source: Mouser Electronics)

For EV charging, the high efficiency and compact size of SiC devices are a good fit, for both on-board chargers in a vehicle and off-board use in a charging station. By enabling greater efficiency and the use of higher voltages, SiC devices can help reduce the size of cabling, thus decreasing the amount of copper needed.

Conclusion

Batteries are a vital part of many technology products; but engineers need to be careful in how they specify and select them—both to minimise their environmental impact and to improve system designs by reducing power consumption and extending battery life.

By using battery development tools, design engineers can ensure they optimise their choice of battery and how their system uses the energy that it provides. And by picking the best components, such as SiC semiconductors, they can minimise the power consumption of their designs, thus reducing the demands on the battery.

Mouser Electronics