In thermal runaway, failures spreads from one component to another and leads to system-wide problems, so it is critical to identify problems using techniques such as hot spot detection.
As technology progresses, electronics are getting increasingly powerful and compact. This climbing performance-to-size ratio is good news for end users’ convenience and cost, but it can also introduce some reliability concerns. Thermal runaway is one of the most prominent of these issues today.
Product design, production mistakes and poor implementation practices can all lead to electronic components failing. Realistically, some of that failure is inevitable to an extent, but basic fixes and replacements can often mitigate these rare, smaller issues. In thermal runaway, this failure spreads from one component to another and leads to system-wide problems, so it is critical to prevent it as much as possible.
What Is Thermal Runaway?
Thermal runaway is a phenomenon where excessive heat in a component leads to exponentially rising temperatures across the entire device. It causes lithium-ion batteries to overheat, leading to more than 100 fires in New York City in 2021 alone. While today’s lithium-ion batteries catch fire less often than earlier models, thermal runaway is still prevalent.
Runaway occurs when a component like a battery or a microprocessor emits more heat than its surroundings can dissipate. Consequently, temperatures in surrounding parts will likewise rise. This increased heat speeds the chemical reaction rates within the device, which pushes temperatures even further, creating a destructive cycle of overheating.
As electronics like Internet of Things (IoT) devices become increasingly compact, internal temperatures can rise faster. Because components are closer, excess heat from one can more easily increase the reaction rate in another, leading to thermal runaway.
This exponential rise in temperature eventually causes component malfunction, often breaking the entire device. If the process happens quickly enough, it can lead to more dramatic side effects like fires or explosions. With experts predicting IoT connections to almost double by 2030, addressing this issue is becoming increasingly crucial.
Identifying Hot Spots to Prevent Thermal Runaway
Thermal runaway is a serious but preventable issue. One of the best ways to address and prevent it is by identifying hot spots — areas of the circuit that are more likely to experience high temperatures. Focusing on these areas throughout the product lifecycle can minimize risks and reduce the damage if an issue does occur.
The first step to identifying hot spots is determining these areas in product design. Lithium-ion batteries — which generate heat when delivering power and charging — are some of the most common. Other typical hot spots in electronics include components with high or complex workloads like microcontrollers.
Once manufacturers know which components are most likely to experience high heat, they should design the device around cooling these areas. Which cooling methods are most effective depends on the product in question, so it is essential to consider the device’s form factor, power consumption and end-use environment.
Larger systems can accommodate cooling hardware like fans, heatsinks, liquid cooling tubes or fins for convection cooling. However, small IoT devices may need more space for these extra components, so manufacturers must consider other methods.
Because vertically mounted power supplies transfer more heat to other components, opting for a horizontal design instead can help. Using parts with lower power needs will also help, as these alternatives will generate less heat as they operate. Thermally conductive gels, pads and films can help dissipate heat in the absence of larger metal heatsinks.
Industrial-grade, larger electronics work better with other heat dissipation methods. Fans may not be applicable in harsher environments where moving parts are vulnerable to breaking, but metal heatsinks and liquid cooling offer a more robust solution. Spreading components out over a larger horizontal surface area will also improve conduction cooling and prevent heat transfer.
Hot spots can also arise from production errors, so manufacturers should look for them in quality control. One of the most effective ways is to run electronics in a controlled environment under a thermal imaging system. The results from these tests can reveal where issues typically occur, informing any necessary design or production process changes.
If several tested devices feature loose bolts that cause hotspots from increased movement, manufacturers can revisit the part of the line that fixes these components. They may need to recalibrate the machine, train employees differently or take other steps to prevent these mistakes in the future.
Automating these quality checks with artificial intelligence (AI) is often the best way forward. These technologies remove human error from the equation and can analyze thermal images faster than human employees. AI is also better at noticing trends in large datasets than people, so as manufacturers create more products, these models will provide more insight into how to improve them.
Even well-designed products can experience high temperatures as end users apply them in various situations. Consequently, it is vital to continue monitoring circuit hot spots throughout implementation to aid timely adjustments and prevent thermal runaway.
On-device temperature monitoring technologies near hot spots can continuously gather and analyze temperature data. When a component’s heat nears unacceptable levels, these systems can signal changes throughout the device to compensate for it.
In larger systems with appropriate hardware and power, that could look like increasing fan speed. Smaller devices could use software-based fixes like distributing workloads or cutting off parts of the circuit to prevent runaway.
Providing end users with guidance on proper usage will help prevent thermal issues from user error. Overcharging is one of the most common causes of runaway in practical use, so informing users of appropriate charging times is crucial. Lights or beeping that indicate sufficient charging can help remind end users to unplug devices. Other information — like tips for where to place appliances and why to keep them away from other high-heat machines — will also help.
Finding Hot Spots Is Key to Addressing Thermal Runaway
Thermal runaway threatens device longevity and user safety in some cases. Electronics manufacturers must address this issue to avoid these outcomes — that begins with identifying hot spots in the device.
When companies understand where high heat arises in their products, they can take appropriate steps to mitigate it. Repeated monitoring throughout quality control and implementation will offer more assurance that electronics perform as intended. Manufacturers and end users can then rest assured that their devices are safe.
|Emily Newton is a technology and industrial journalist who enjoys discovering how the IoT is impacting different industries. Emily is editor in chief of Revolutionized – an online magazine exploring trends in science, technology and industry. Subscribe to her newsletter to keep up with the latest.
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