Inside the OPPO Find X5 Pro’s cooling system, the secret star of this flagship phone

The OPPO Find X5 Pro is a phone with several showpiece features that compete for the spotlight. It has an advanced 120Hz OLED screen with ultra-high peak brightness and a dynamic variable refresh rate. Super-powered SUPERVOOC technology replenishes its battery in a flash whether you use a cable or wireless pad. Its camera takes low-light photography and video to a whole new level.

These are the stars of the show. But just as every pop star has a team working behind them, and all of us rely on a support network of friends and family, the OPPO Find X5 Pro is backed up by something just as important. This is the OPPO Find X5 Pro’s cooling system.

It is what lets the OPPO Find X5 Pro keep a cool head in any situation. You won’t feel its back heat up uncomfortably when playing a rich 3D game. You won’t have to stop recording 4K video because the phone overheats. A great cooling system unlocks the full potential of a powerful phone.

PC-grade cooling in a miniature shell

Perfecting cooling in a phone is not a simple process either. The OPPO Find X5 Pro cannot use a fan like a full-size PC. It uses a full passive cooling solution, generating zero noise. And all its pieces have to slot in around the core components in a precision-crafted case less than 9mm thick.

Imagine having to fit a week’s worth of clothes into a suitcase that is already full. This was the challenge for OPPO’s engineers. However, the OPPO Find X5 Pro cooling system is not treated as a pure logistical block puzzle. Each step of the process is guided by the human body’s perception of temperature. There can be no hot spot on the phone’s back your fingers will notice, no heat build-up to distract from whatever you choose to do with your OPPO Find X5 Pro.

The phone’s cooling system’s ultimate goal is to go unnoticed and uncredited. But perhaps it is time to give the OPPO Find X5 Pro’s cooling some credit and figure out how this unlikely goal was achieved.

OPPO vapor chamber design

A vapor chamber is the heart of the phone’s cooling system. From the outside this may simply look like a thin sheet of metal, but there’s an intricate little world inside its walls.

The vapor chamber is an ultra-thin copper cave injected with a very small amount of liquid. As heat from the components underneath conducts through the chamber’s bottom, this liquid evaporates and spreads throughout the chamber. It condenses on the outer walls, spreading the heat it held over a much larger surface area, dissipating the heat in the process.

The larger a vapor chamber is, the wider and more effectively it can move heat away from the components that generate it, like the primary processor. OPPO has managed to increase its size by 75% over the previous generation.

It almost completely covers the battery and SoC, the main processor, which is exactly where you want such a chamber to sit. When fast-charging or playing a console-grade game, any heat generated is quickly spread across a huge area so it can dissipate almost unnoticed, out through the phone’s back.

But the vapor chamber is only a single part of a whole one-way circulatory system that runs through the phone. Advanced materials engineering is used to pull warmth away from all the key components.

The display driver and display panel, the SoC and wireless charging coil are some of the heat-generating areas that require extra attention. OPPO developed bespoke solutions for these components based around three materials: copper, graphite and graphene.

Advanced materials engineering

Copper is the traditional material for cooling components. However, when devising heat management for the display, OPPO’s R&D team found they could improve both heat dispersal and the resilience of the screen by using a copper sheet sandwiched with an ultra-thin layer of graphite.

It helps keep the display cool while it delivers searing brightness at 120Hz, and also dramatically improves the drop resilience of the OPPO Find X5 Pro by increasing structural integrity.

The other hot zones in a phone, like the motherboard and battery coil, did not need the same level of structural support, letting OPPO R&D dig even further into possible solutions. They landed on a graphene film, where the carbon from graphite is arranged in a single-atom layer, which dramatically improves strength and conductivity.

Graphene is a wonder material, but producing it on a mass scale is no easy task. To turn graphite into graphene involves a process called sintering, where the graphite is heated at temperatures up to 3100 degrees centigrade. Such high temperatures were unattainable for mass industrial production. OPPO is the first in the industry to achieve it, resulting in the highest quality, most conductive graphene film.

Following years of experimentation and fine tuning, OPPO has achieved a 50% improvement in thermal conductivity of the graphene film compared to its first-generation process, for industry-leading performance.

The compromise-free cooling system lowers the OPPO Find X5 Pro heat to a comfortable range even when running a 90/120 Hz high refresh game, and keeps the phone cool while charging.

More than passive cooling

Its pioneering approach does not stop there. OPPO has also developed an active solution to enhance the Find X5 Pro’s cooling performance.

OPPO created the new Ice-skin* case to keep the phone cool while protecting it. The core of the case is Glacier Mat, an innovative material that achieves a self-replenishing cooling cycle without using any power at all.

Glacier Mat is a hydrogel layer co-developed with Wuhan University, one of the top universities in China.  Hydrogel pulls moisture from the air, which is then evaporated through the heat generated by the device. It is an ideal material to bring the heat out from the device. However, ordinary hydrogel cannot replenish water after evaporation so it can’t be used as a long-term cooling solution.

Glacier Mat is different, and OPPO engineers took inspiration from our skin’s sweat production to solve the problem. Glacier Mat is a modified hydrogel that can re-absorb moisture from the air at low temperatures, after the water initially held is evaporated through the process of cooling the OPPO Find X5 Pro, creating a circular cooling cycle. Although it sounds simple, it cost OPPO’s engineers a great deal of effort to put this theory into practice and mass production in less than half a year.

Testing shows a 2-3 degree drop in phone temperature when gaming with the Ice-skin case attached. A cooler phone improves comfort during play, and ensures the highest frame rates for smoother experience. The most important part: the Ice-skin case achieves all this with minimal weight, zero power use and zero noise.

The phone buyer typically does not have to concern themselves with the work put into figuring out how to arrange different materials to dissipate heat, for the most defect-free result. However, it has a key role in letting OPPO Find X5 Pro owners play games, film videos and experience the full power of a supernova-bright AMOLED display without needing to worry about overheating. Carefully designed cooling is the unseen hero of this revolutionary smartphone.

*Only available in China for now