Apple's Patent Background

Apple's patent overview starts off by stating that the US is reliant on fossil fuels which has forced the government to maintain complicated political and military relationships with unstable governments in the Middle East, and has also exposed our coastlines and our citizens to the associated hazards of offshore drilling. These problems have led to an increasing awareness and desire on the part of consumers to promote and use renewable energy sources.

The Environmental Assessment Tool (EPEAT) is presently used to produce data that helps consumers evaluate the environmental friendliness of electronic products. Moreover, the EPEAT score for an electronic product could be increased by providing a renewable energy source for the product.

As a consequence of this increased consumer awareness, electronics manufacturers have become very interested in developing renewable energy sources for their products, and they have been exploring a number of promising renewable energy sources such as the hydrogen fuel which is used in hydrogen fuel cells. Hydrogen fuel cells have a number of advantages. Such fuel cells and associated fuels can potentially achieve high volumetric and gravimetric energy densities, which could potentially enable continued operation of portable electronic devices for days or even weeks without refueling. However, it is extremely challenging to design hydrogen fuel cell systems which are sufficiently portable and cost-effective to be used with portable electronic devices.

Apple's Proposed Solution

Apple's invention generally relates to the design of a fuel cell system which is capable of both providing power to and receiving power from a rechargeable battery in a portable computing device. This eliminates the need for a bulky and heavy battery within the fuel cell system, which could significantly reduce the size, weight and cost of the fuel cell system. This fuel cell system includes a fuel cell stack which converts fuel into electrical power. It also includes a controller which controls operation of the fuel cell system. The fuel cell system additionally includes a power link that transfers electrical power between the fuel cell system and the portable computing device, and a communication link that provides communication between the portable computing device and the controller for the fuel cell system. The controller could regulate both the electrical power provided by the fuel cell system to the portable computing device and the electrical power provided by the rechargeable battery to the fuel cell system. More details regarding the summary of this system could be found in the patent application.

A Future Fuel Cell System for iOS Devices and the MacBook

Apple's patent FIG. 1A provides an external view of a portable fuel cell system 100 which includes a fuel cell housing 101, which contains a power module with a fuel cell stack. The fuel cell housing is configured to receive a detachable fuel cartridge 104, which contains a suitable fuel, such as sodium borohydride (NaBH.sub.4). Moreover, the fuel cell housing could provide power to a portable electronic device through a special interface 110, which is later confirmed to be Apple's MagSafe.

Converts Hydrogen or Hydrocarbon Fuels into Electric Current

In Apple's patent FIG. 1B shown below they illustrate some of the internal structures of the fuel cell system 100 noted above in FIG. 1A. More specifically, the fuel cell system includes a fuel cell stack 102 which produces electrical power by converting a source fuel, such as hydrogen or a hydrocarbon, into an electric current and a waste product.

The fuel cell stack comprises a stack of fuel cells, wherein each a fuel cell contains an anode, a cathode, and an electrolyte between the anode and cathode. Electricity may be generated by two chemical reactions within the fuel cell. First, a catalyst at the anode oxidizes the fuel to produce positively charged ions and negatively charged electrons. The electrolyte may allow ions from the oxidation process to pass through to the cathode while blocking passage of the electrons. The electrons may thus be used to drive a load connected to the fuel cell before recombining with the ions and a negatively charged atom (e.g., oxygen) at the cathode to form a waste product such as carbon dioxide and/or water.

The fuel cells within the fuel cell stack may include electrochemical cells that convert a source fuel into electric current and a waste product. For example, the fuel cells may be proton exchange membrane (PEM) fuel cells that use hydrogen as a fuel. The hydrogen may be catalytically split into protons and electrons at the anode of each PEM fuel cell. The protons may pass through an electrically insulating membrane electrode assembly (MEA) to the cathode of the PEM fuel cell, while the electrons may travel through a load to the cathode. The protons and electrons may then react with oxygen atoms at the cathode to form water molecules as a waste product.

Alternative Fuel Cell Sources & Stacking Fuel Cells

Beyond Hydrogen or Hydrocarbons, Apple states that Alternative fuel cells may correspond to solid oxide fuel cells, molten carbonate fuel cells, direct methanol fuel cells, alkaline fuel cells, and/or other types of fuel cells.

Additionally, Apple states that due to individual fuel cells not being able to generate a voltage (e.g., 0.5-0.7 volts for PEM fuel cells) enough power to drive some components in a portable electronic device (e.g., processors, peripheral devices, backlights, displays, Universal Serial Bus (USB) ports, etc.), the fuel cells may be electrically connected in a series configuration. For example, a set of 25 PEM fuel cells may be connected in series within the fuel cell stack to increase the voltage of the fuel cell stack to roughly 12.5-17.5 volts. This increased voltage may then be used to drive components with operating voltages which are at or below the voltage of the fuel cell stack.

Power from the fuel cell stack feeds into circuitry 106 that performs control functions and performs direct-current (DC)-to-DC conversion operations before the power feeds through the MagSafe connector to power portable electronic device 120. The power could also be directed to an internal rechargeable battery 108, which is configured to store excess power generated by fuel cell stack 102.

Power Link: MagSafe or Wireless

Note that interface 110 may provide physical links for both power and communication. However, in an alternative embodiment, interface 110 may provide a single physical connection for the power link and a wireless bi-directional data link. In other embodiments, the power link may also be wireless.

Daisy-Chained and/or Operate as a Standalone Device

In an alternative configuration, portable the fuel cell system could be "daisy-chained" so that it is connected to another fuel cell system which may or may not be connected in turn to another computer system or computing device. Moreover, portable the fuel cell system could also operate as a standalone device, wherein it operates to charge up internal battery 108.

Apple's patent FIG. 2A illustrates details more of the internal structure of a fuel cell system; patent FIG. 2B illustrates how the fuel cell system could use two DC/DC converters. During operation, the master control board (212) receives power from the fuel cell stack and converts the power using a first DC/DC converter 280 into a battery voltage which is suitable for charging the internal battery. Next, a second DC/DC converter 282 converts the battery voltage into a voltage suitable for powering a portable electronic device, and this voltage is fed into the MagSafe board 224, which feeds the power to the portable computing device through the MagSafe interface. Obviously MagSafe is Apple's preferred interface but do state that USB could be used.

Fuel Cell System Coupled to an External Power Source

Apple's patent FIG. 4 illustrates a fuel cell system 400 which uses an external battery to store operating power

Note that, because the capacity of a rechargeable battery of an external electronic device (e.g., a laptop) could be sufficiently large, regulating a fuel cell operating parameter by directly charging an external battery with the fuel cell allows the control process to be highly reliable.

Apple's patent FIG. 5 shown below presents a flow chart illustrating how a fuel cell system could use an external rechargeable battery on a portable electronic device to maintain hydrogen pressure around a set-point.

Both of Apple's patent applications were originally filed in Q3 2010 by inventors Vijay Iyer and Bradley Spare. Apple's second patent on this topic covered the same territory but put emphasis on the new fuel cell system also being cost-effective.

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Other Noteworthy Patent Applications Published Today

For those of you who are interested in knowing every technical detail about Apple’s Magic TrackPad, you’re in luck. Two of Apple’s detailed patent applications have been published today for your review.   

Apple’s patent application number 20110310536 covers the moveable foot of the Magic TrackPad which is shown above in figures 7 and 9. The second patent application is number 20110310029 covering the main technology behind the multitouch Magic TrackPad. Here are two temporary links to these patents which are good for 24-48 hours: One, Two.

Notice: Patently Apple presents a detailed summary of patent applications with associated graphics for journalistic news purposes as each such patent application is revealed by the U.S. Patent & Trade Office. Readers are cautioned that the full text of any patent application should be read in its entirety for full and accurate details. Revelations found in patent applications shouldn't be interpreted as rumor or fast-tracked according to rumor timetables. Apple's patent applications have provided the Mac community with a clear heads-up on some of Apple's greatest product trends including the iPod, iPhone, iPad, iOS cameras, LED displays, iCloud services for iTunes and more. About Comments: Patently Apple reserves the right to post, dismiss or edit comments.

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