Apple invention uses ferrofluids to enhance induction charging performance
As part of continued research into efficient wireless chargers -- perhaps powerful enough to rival Lightning -- Apple on Tuesday received a patent for an induction charging method that uses ferrofluids to reduce or negate energy loss typical of such systems.
Outlined in Apple's U.S. Patent No. 9,479,007 for an "Induction charging system," published by the U.S. Patent and Trademark Office, the method improves energy transmission by disposing a layer of ferrofluids between an inductive unit's transceiver and receiver coils.
Most inductive chargers work on the same principle: induced current. The method involves sending energy from a charging station to a battery powered device through an inductive coupling.
More specifically, an induction coil in the charger -- primary coil -- creates an alternating electromagnetic field, which is converted back into an electrical current by the receiving coil -- secondary coil -- in the mobile device. Apple's own Apple Watch employs a variation of this technology to charge up in a relatively fast and reliable manner.
Source: USPTO
Compared to wired, or direct contact, charging methods, inductive chargers are generally less efficient and require larger internal components to operate. In addition, the sensitive inductive coils must be aligned correctly to achieve a good coupling, as poor matings decrease efficiency and could lead to troublesome thermal issues. With Apple Watch, for example, the coupling issue is addressed by disposing magnets in both the charger cable and watch to ensure a decent fit.
Today's invention aims to bypass the pitfalls above by installing a helper layer of ferrofluids in either the charger or portable device.
Ferrofluids are liquids that contain ferromagnetic particles suspended in a carrier fluid, typically water or an organic solvent. The particles are able to move freely within the liquid and, importantly, become magnetized when exposed to a magnetic field, allowing gravitation toward magnetic flux.
Applied adjacent to an induction charging system, a contained ferrofluid layer can greatly increase energy transfer performance by minimizing the effects of coil misalignment. In practice, the ferrofluid is attracted to, and shaped, by generated magnetic flux to a position between the transmit and receive -- primary and secondary -- coils.
Diagram illustrating ferrofluid layer (25) focusing flux (15) between coils (14 and 19).
In some embodiments, the ferrofluid layer can create a bridge between the two coils, which in turn creates a preferential path across which the magnetic flux travels, Apple says. Focusing flux between the two coils mitigates loss due to misalignment, thereby increasing electromagnetic energy transfer efficiency and potentially decreasing charge times.
The document goes on to explain in detail various working embodiments of the present invention.
As with any patent, it is unclear if Apple intends to market a ferrofluid-enhanced inductive charger in a future product. That being said, almost all Apple products could benefit from inductive charging technology, from Apple Watch to iPhone to the latest MacBooks and accessories.
After a successful rollout of wireless charging options from Samsung, Apple users eagerly anticipate the feature to land in a next-generation iPhone. Recent reports suggest an inductive charging iPhone could arrive sooner rather than later, as Apple is reportedly in the process of vetting manufacturers of wireless chips capable of charging its smartphone flagship.
Apple's ferrofluid enhanced inductive charging invention was first filed for in February 2014 and credits Eric S. Jol, Ibuki Kamei and Warren Z. Jones as its inventors.
Outlined in Apple's U.S. Patent No. 9,479,007 for an "Induction charging system," published by the U.S. Patent and Trademark Office, the method improves energy transmission by disposing a layer of ferrofluids between an inductive unit's transceiver and receiver coils.
Most inductive chargers work on the same principle: induced current. The method involves sending energy from a charging station to a battery powered device through an inductive coupling.
More specifically, an induction coil in the charger -- primary coil -- creates an alternating electromagnetic field, which is converted back into an electrical current by the receiving coil -- secondary coil -- in the mobile device. Apple's own Apple Watch employs a variation of this technology to charge up in a relatively fast and reliable manner.
Source: USPTO
Compared to wired, or direct contact, charging methods, inductive chargers are generally less efficient and require larger internal components to operate. In addition, the sensitive inductive coils must be aligned correctly to achieve a good coupling, as poor matings decrease efficiency and could lead to troublesome thermal issues. With Apple Watch, for example, the coupling issue is addressed by disposing magnets in both the charger cable and watch to ensure a decent fit.
Today's invention aims to bypass the pitfalls above by installing a helper layer of ferrofluids in either the charger or portable device.
Ferrofluids are liquids that contain ferromagnetic particles suspended in a carrier fluid, typically water or an organic solvent. The particles are able to move freely within the liquid and, importantly, become magnetized when exposed to a magnetic field, allowing gravitation toward magnetic flux.
Applied adjacent to an induction charging system, a contained ferrofluid layer can greatly increase energy transfer performance by minimizing the effects of coil misalignment. In practice, the ferrofluid is attracted to, and shaped, by generated magnetic flux to a position between the transmit and receive -- primary and secondary -- coils.
Diagram illustrating ferrofluid layer (25) focusing flux (15) between coils (14 and 19).
In some embodiments, the ferrofluid layer can create a bridge between the two coils, which in turn creates a preferential path across which the magnetic flux travels, Apple says. Focusing flux between the two coils mitigates loss due to misalignment, thereby increasing electromagnetic energy transfer efficiency and potentially decreasing charge times.
The document goes on to explain in detail various working embodiments of the present invention.
As with any patent, it is unclear if Apple intends to market a ferrofluid-enhanced inductive charger in a future product. That being said, almost all Apple products could benefit from inductive charging technology, from Apple Watch to iPhone to the latest MacBooks and accessories.
After a successful rollout of wireless charging options from Samsung, Apple users eagerly anticipate the feature to land in a next-generation iPhone. Recent reports suggest an inductive charging iPhone could arrive sooner rather than later, as Apple is reportedly in the process of vetting manufacturers of wireless chips capable of charging its smartphone flagship.
Apple's ferrofluid enhanced inductive charging invention was first filed for in February 2014 and credits Eric S. Jol, Ibuki Kamei and Warren Z. Jones as its inventors.
Comments
As long as the unit you set your device on has to be plugged in, you aren't really "wireless",
and you're still confined to a certain radius based on that cord length anyway...
So, are the economies of space gained by removing the lightning or whatever connector from the equation,
really not counterbalanced by whatever internal receptors receive and convey the charge?
Or is the only real difference and benefit, closing that portal to incursion of moisture & dust?
2) What power option wouldn't be confined to a radius?
- Just that much easier (small conveniences are still nice). Just lay onto a mat or holder and walk away. Magnets line it up for correct contact.
- The end of cord is something more substantial (holder, mat), so cords aren't flopping and falling. Looks neater.
- The device being charged (e.g. iPhone) will become more reliable, waterproof, etc. Less likely to break the connector, hit cord & pull off table, etc.
- While current induction tech requires very close proximity & aligned coils, physical contact isn't mandatory, so some small amount of distance for "wireless" charging is possible and we see some early solutions getting a bit of distance (though clearly efficiency goes down per the inverse square law).
- Technology may start to be built into furniture / surfaces, so the clutter goes down and convenience goes up.
Important not to get too caught up in the hype though. The inverse square law for energy dissipation over distance means that only very low level charging can occur any distance (even a few meters) from the source. Batteries and the ability for a strong charge will remain important for the foreseeable future. "Safe" fast charging will be more useful than wireless charging.
2) effectively, solar - just kidding, 'none' is the answer, which is why I'm asking, why get all excited about inductive charging, when you're still effectively tied to that base?
Agreed!
ive never liked wireless charging for anything that has a large battery. For the watch is fine, but for 3,000MWH batteries, it's too inefficient. So far, it's been more of a marketing point than a truly useful technology for phones. Whether this increases coupling enough for it to work really well, is something I can't say. But, it's interesting that Apple is pursuing this course.
You're right about the square law, but maybe not. It depends on how it's done. While free dissipation will obey the square law, the energy radiation can be focused. It looks as though this technology helps with that, as well as with the alignment problem, by providing a path for the energy to flow more directly. These devices are in direct contact, after all, so there isn't much of that diffusion taking place anyway. If we held the charger an inch away, much dissipation would occur, and the losses would be tremendous.
I still think Mike1's point may have validity. Halfway charging your device one time, 75% the next, 40% the next, may turn out to be different from 2% then 8% then 3% etc. Apple's battery care standards don't really address that particular sort of partial-cycle charging. If anyone knows of actual studies that do address it, I'd very much appreciate being directed to them...
So much to learn, so little ability to...uh...what was I saying?