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    The Need for Thermal Management in Long Distance Qi Chargers

    • 4 min read

    The Need for Thermal Management in Long Distance Qi Chargers



    It seems that wireless chargers have been around for quite a few years now, yet people are still confused about their specs, features, and technical capabilities. The novelty of owning a wireless charger seems to have worn off over time, leaving people with questions regarding their specifications and potential issues.

    One question in particular always seems to rise and it involves their proclivity to heat up when used over long periods. This is also true foryour average long-distance Qi charger or charging station, as people who have had the pleasure of using them with high-end devices couldn’t help but notice how hot both the chargers and the phones would get during the charging process.

    Although wireless charging is generally considered more practical and convenient for a variety of reasons, the fact of the matter is that even when used at low intensity, they still tend to heat up quite a bit. 

    So this raises another question for the future – can manufacturers come up with a practical thermal management system for future releases or should we simply make peace with the fact that the whole process is meant to be rather hot?

    Now, it should be said that wireless charging is undeniably faster, easier, and more convenient than traditional wired charging. Some people take no issue with the high temperature as long as the process doesn’t pose any actual risks. 

    This sentiment is echoed by many of those who own wireless chargers at this point, but this doesn’t mean the subject isn’t worth talking about.

    Heat is a by-product of the wireless charging process

    We should perhaps try to understand from the get-go that wireless charging is a process that relies in part on a constant current flow between the charger and the target device. This whole process is prone to shifts in overall temperature no matter how well-made the charger is, although a better design can help improve the situation.

    Having said that, know that sudden temperature changes can result in poor performance for the device in the short run, not to mention the reduced battery life cycle. It also seems that many manufacturers consider thermal properties as a secondary design consideration when developing their chargers.

    This needs to change going forward becausenobody wants a long-distance Qi charger that can potentially ruin the phone’s battery long-term. Then again, a simple explanation for this seeming design flaw is the desire to constantly shrink the chargers and make them more accessible.

    We should also point out that major strides have been made in EV batteries, technologies that allow them to deliver more power and require less frequent charges. Even so, the ability to design an effective cooling system is still among the major challenges that manufacturers have to face with new releases.

    Commonly used battery thermal management methods

    It seems that the larger the battery size, the higher the rate of current flow and heat generation. This presents an interesting challenge for future chargers, and it’s an issue that current generation Qi chargers do not seem to address. For the most part, the most commonly used battery thermal management methods are:

    PCM –This refers to Phase Change Materials that absorb heat by charging from a solid to a liquid state. These materials are designed to absorb heat while presenting a minute change in overall temperature. One major downfall is the fact that volume changes can restrict their application when used repeatedly over extended periods.

    Fin cooling –Although it is a good idea to employ cooling fins for a more adequate temperature maintenance, this method also has its share of cons. For instance, cooling fins increase the surface, which in turn increases heat transfer rates. The thing about these fins is that they typically possess a high thermal conductivity, which can efficiently cool down the charger when used. The main issue here is the extra weight they bring to the charging station, which also translates into a more bulky build.

    Air cooling –At this point, this is the preferred method that most manufacturers prefer for a handful of reasons. The majority of long-distance Qi chargers employ an air cooling system in that they rely on regular airflow to handle all the cooling.As such, the air that runs over the surface of the charger carries away the heat dissipated by the device. Thus, the method is rather simplistic and reasonably effective.

    Liquid Cooling –A not-so-popular cooling method, some chargers do indeed employ liquid cooling for temperature management. Liquid has a higher heat conductivity compared to air, which means that the system can cool down a lot faster overall. Unfortunately, liquid cooling systems are very large and can render the charger highly impractical.

    Solving the thermal problem

    Every new technology presents challenges in its inception, it is the nature of new technologies everywhere. In regards to wireless charging, the challenges are more thermo-conductive rather than technological, which fortunately means that the solution that manufacturers need to come up with will likely be a simple one.

    Going forward, the main concern is how to minimize heat generation and how to spread it quickly once produced to prevent localized heating. The assertion here is that any change in charger architecture will need to first and foremost provide a practical solution to the heat generation problem before addressing the heat dissipation.

    At this point,a decent long-distance Qi charger generates a reasonable amount of heat when operational, but this can differ quite a lot from one charger to another. No two wireless chargers generate the same amount of heat, not unless they operate at similar parameters and handle an identical charge delivery.

    Although we don’t expect wireless chargers to plateau in regards to their technological capabilities, we can see how magnetic induction will soon enough require certain innovations to ensure that new chargers handle the ever-growing requirements of increasingly larger batteries. 

    All in all, we can assume that components that have worked for other chargers in the past will eventually have to be changed in favor of more heat-dissipating materials.