In the drone market, all forecasts show growth in commercial and military applications. But when you look at the demands for security and performance to excel in these markets, there are significant challenges to surmount when it comes to designing and building a robust, reliable power source for these unmanned aerial vehicles (UAVs).

Whether these drones are delivering packages and essential supplies in remote locations, or capturing aerial imagery, OEMs may run into some challenges when launching a commercial or military-grade aircraft, such as:

  • Limitations in charge capacity limit the distance these vehicles can travel
  • Lack of standards in the current drone market
  • Lack of safety standards in the drone battery market

These challenges offer opportunities. Not just an opportunity to grow as an OEM, but an opportunity to lead, and emerge as the standard-bearer.

For example, the market hasn’t matured to a point where industry standards are in place, but they are coming. Thus, UAV makers that set serious intentions about making inroads in military and commercial markets have an opportunity to put their stakes in the ground and build their reputation on the tenets of ruggedness, performance, and longevity.

Safety is paramount in the design of a drone. Most drone manufacturers are more than willing to invest in safety systems to safeguard their customers’ investment and provide a better quality drone. Managing costs still takes high priority, but when it comes to mission-critical UAVs, the expense will not be secondary to safety. These machines have a mission, or they may be riding on a brand’s already established reputation. Casualties due to a failure in mechanical and thermal design are simply not options and must be minimized.

The battery industry is evolving and new chemistries and technologies are emerging which will help make safer, longer flights possible. When you’re engaging with a company that designs the battery solution for your UAV, you will want to choose one that understands the design considerations needed for the application and has the experience and capabilities to build a safe, intelligent, and high-quality battery management system. Here are some insights about the battery design process to consider as you prepare for your entry into the commercial and military UAV market.

Military-grade UAV DroneHow to build a safer, more reliable UAV power system

The power source for a commercial or military-grade UAV will succeed when the end-user and other affected people don’t have serious concerns about its reliability, its safety, and whether it can complete its task.

With that in mind, the most important quality of the power source — the battery pack — is one that keeps the drone in the air for as long as possible. Maximizing flight time takes top priority in military and commercial applications. But designing that safe, reliable power system is more complex than it would appear when it comes to aviation.

Power source

First, you’ll need to identify the best battery type for flight applications. Unlike a stationary object, a large, heavy battery is counterproductive to powering aircraft. A heavy battery would consume an excess of energy to maintain the aircraft’s lift and velocity, canceling its benefits.

Thus, identifying the right battery starts with finding the chemistry & format that yields the optimal performance solution. At Inventus Power, we work with our customers to identify the ideal chemistry and form factor needed for the intended application and discuss various tradeoffs that they may need to consider. For drone applications where battery weight affects performance, we may recommend a lithium polymer cell because it has a high energy/weight ratio and offers flexibility in size versus a cylindrical or prismatic cell. However, the tradeoff will be in the battery’s mechanical design which will need to account for possible mechanical and thermal issues. Cylindrical and prismatic format cells may also be implemented depending on the design criteria.

Electrical system performance

In a drone application, electrical system performance is another key consideration. Here are a few to think about:

  • Discharge: Does the drone require the torque of a high-rate discharge battery to keep it in flight in challenging conditions? Or in a particular application, is there still value in sacrificing the airtime gained from a mid-rate battery?
  • Charging requirements: When a mission outlasts battery life, removable batteries get the aircraft back in the air instantly, versus grounding the entire unit for several hours in a charger.
  • Current sourcing: Can the battery meet the supply needs of high current motors used in demanding commercial and military applications?
  • Housing design: Which lightweight material can best take shock, impact, and vibration for the battery housing?

Designing a safe, flightworthy BMS

The design of the battery management system (BMS) goes hand-in-hand with safe operation. The goal is to protect the end-user's investment, along with preventing casualties. Using best practices in thermal and mechanical design is critical to safeguarding the device from having the power cut out mid-flight or bursting into flame.

For example, placing the battery pack near a hot zone such as the circuit board can create conditions for overheating and, worse, thermal runaway of the battery cells. Correct placement and using thermal insulating material are ways to minimize the possibility of this worst-case scenario.

Anticipating BMS performance needs

Commercial Drone Drop Delivery When the craft is airborne, gathering footage, or transporting items for drop delivery, the power source should never be in doubt. Not only is this a very large investment at stake, but so are the property and lives on the ground.

A battery management system with built-in processing and software conveys mission-critical and accurate information about battery life and available energy, so they can safely and successfully guide the drone to job completion.

When designing a top-performing battery for an unmanned aircraft used for commercial and military applications, here are some things that can be  monitored, communicated, and managed through the battery management system:

Cell Management

This is controlled through the BMS and can provide cell balancing as well as pack balancing depending on the battery pack configuration. Managing and balancing these cells maximizes the overall battery life and provides greater power efficiency during operation.

Fuel gauge

Measures and can transmit real-time data to the ground on remaining energy so the operator can plan and adjust the mission with greater precision. The fuel gauge will also automatically adjust its measurements to compensate for the aging and eventual degradation of the battery pack over time.

Real-time clock

Provides accurate time measurements for operations that require precision in timing, such as making a delivery or capturing a moment via aerial imagery.

Protection circuit module

Located in the circuit board, the PCM monitors various sensors in the BMS to ensure the battery and its surrounding systems don’t overheat and trigger thermal runaway. A robust BMS is constantly monitoring for these conditions by taking multiple measures, including:

  • Over voltage protection
  • Under voltage protection
  • Over current protection
  • Short circuit protection
  • Over temperature protection
  • Primary, secondary, and tertiary protection circuitry
  • Cell voltage monitoring & recording
  • Cell lifecycle recording

Superior BMS communication with the end-user (and within the device)

Being prepared for thermal runaway is critical, even if it’s less likely to occur in a battery that’s designed with a sophisticated BMS, constructed with the best materials, and built to quality standards. Because, unlike a ground vehicle, the standard battery shut-off response in a fault condition will surely destroy this $50,000+ aircraft. That’s why UAVs should have an extra layer of protection in the form of software control that initiates an emergency landing to safely get the aircraft on the ground.

Ready to grow, ready to lead

Growing market opportunities in the U.S. drone market mean increasing focus on performance and safety. High-quality mechanical and electronic design in the battery pack is key to producing the best in class.

Finding the right battery partner will be key in ensuring success in the growing UAV market. As a global leader in advanced battery systems, Inventus Power may just be the partner you need to bring your drone to life. We have over 60 years of battery industry experience working across a broad range of markets and applications. Our technical expertise in battery pack design and BMS development coupled with our emphasis on safety and quality aligns well with the needs of the commercial and military UAV industry.

Contact us today to start a conversation!