apple: what lithium-ion battery limits could mean for iphone 5

Guest post by Noam KedemNoam Kedemis, vice president of Energy Marketing, Fremont, California-
Companies that make batteries for consumer electronics, electric cars, and storage applications.
Speculation about Apple\'s design of multiple products
The launch of the new iPad has greatly boosted the expected iPhone 5.
It\'s clear that Apple faces some pretty strict design trade-offs between feature settings, form factor and battery life.
The company has rolled it out in its usual engineering extravaganza, but even so, the new iPad is a bit thicker, heavier, and shorter battery life than its predecessor.
What does this mean for iPhone 5?
Others can speculate more subtly about the display and processor options Apple faces.
What I want to focus on is the battery.
From my point of view, the fundamental problem is that while Apple can always rely on
In the Silicon involved, lithium-ion (Li-ion)
Almost all the batteries powered by mobile devices are still: they use the same chemical platform as they did 20 years ago.
No change in battery chemistry, Li-
Ion will impose some restrictions on how Apple uses the design and spec sheet for the iPhone 5.
The new features or upgrades expected in the IPhone 5 that require the battery the most are the display, 4g LTE wireless connection, and a more powerful processor.
The leaked images showed that the retina display increased from three and a half to 4 inch;
This is not surprising because the average display of Android phones now exceeds 4 inch.
4g lte connection seems to be a no
It\'s also smarter considering the needs of mobile video, iCloud features and Android competitors.
We can also expect a faster version of the A5 processor with more powerful 3D graphics.
Each of these new features can generate more energy and generate more heat.
Both of these are challenges for Li. ion technology.
That\'s why the new iPad\'s battery is 70% larger and heavier than its predecessor, but the battery life is still shortened, and it\'s why Apple is facing some tough options for the iPhone 5.
The IPhone 5 will have to be much bigger than its predecessor.
Even if the larger screen makes it possible to increase the X and Y dimensions of the battery, the result may still be a shorter battery lifeIn terms of operation-
The time, cycle life, and calendar life of each charge.
This is because of Lee.
Battery technology is lacking in both energy density and thermal sensitivity.
Energy density determines the amount of running-
The time you can pack into a given size (volumetric)or weight (gravimetric)of a battery.
Unfortunately, Moore\'s law does not apply to batteries.
Since the first Li
In 1991, Ion batteries entered the market, and because of consumer demand for more features and higher performance, the number of transistors in the devices they powered increased by thousands of times. Li-
In the same period, the bulk energy density of ion batteries has only increased by 3 times, and it is increasingly difficult for battery manufacturers to squeeze more energy into it.
Improving packaging efficiency is a way to get higher energy density.
For exampleremovable Li-
The ion bag battery now used in most smartphone models eliminates the protective housing that users need
Replaceable battery.
They are just a sealed bag with carefully stacked or wrapped anode and cathode pieces, partitions between them, and-
Penetrate all these layers-
Liquid electrolyte.
By relying on the smartphone housing for protection, there is more room for active materials that actually store energy.
Packaging efficiency is where Apple may have a slight advantage in the iPhone 5.
There are two ways to place a battery in a smartphone.
One method is two layers of electronic equipment (
Screen and circuit)
\"Carve\" a space for the battery.
This is the way the iPhone 4S takes.
Another option is to use three layers: screen, circuit and battery such as the Motorola RAZR series (
Two RAZR, razr maxx).
At first glance, by allowing a larger battery, the three-tier approach seems to provide a longer run time
Time, but the narrower the battery in the engraving
The Out method actually provides a higher energy density. Li-
Built-in ion bag battery-
In printed circuit boards connected to positive and negative terminals of each unit, active protection against short circuit, overcharge and forced discharge is provided.
The narrow rectangular battery can place the PCB on the short edge, leaving more space for the active material, thus providing a higher energy density than the square battery.
My overall estimate is to keep the engravingout approach -
The X/Y ratio of the new iPhone battery is narrow, similar to the iPhone 4 S-
Compared to a three-tier approach using a more \"square\", it will provide limited but important battery energy density advantagesish” battery.
Another factor here is volume.
The larger screen means that Apple may try to make the iPhone 5 thinner than the iPhone 4S, and if not, a recent leak of thinner screens about integrated touch sensors indicates this.
This will be easier to relate to the engraving method currently used by Apple, especially given the company\'s skills to reduce PCB size in every generation of iPhone and iPad (
Usually by folding more functions into each chip and using an updated manufacturing process).
This method makes more room for batteries that maintain the best X/Y ratio and thickness to maintain maximum energy density and thus operateTime per charge.
Another major battery design problem, thermal sensitivity, is also not conducive to the three-layer design.
Standard Li-
Ion battery chemistry relies on a chemical compound that, unfortunately, reacts with residual moisture to produce the most corrosive hf in all chemical compounds.
Like all chemical reactions, with every 10 degrees Celsius increase in temperature, the process doubles and the smartphone heats up.
Hf will gradually reduce the performance of the battery, thus reducing the cycle and calendar life of the battery.
Reduced operation per charge and discharge cycle-
Until the battery does not last long enough between charges.
Even if you don\'t ride a bike, the battery life will reduce the running time. time.
Heat makes it all happen faster, which is one of the reasons why consumers are often \"locked\" before the phone cools down.
In addition, charging or discharging the battery also generates heat.
The higher power requirements of the IPhone 5 for new features will mean faster discharge.
The consumer\'s impatience requires charging as fast as possible, but when using the same charger as the early iPhone, the more powerful battery needed for the iPhone 5 naturally takes more time to charge.
Using a more powerful charger to reduce charging time can generate more heat and further reduce battery life.
The battery is designed in three layers, covering all heating parts.
A metal heat shield or heat sink can be used, but this adds weight and thickness. A two-
The layer design makes it easier for the hottest part of the device to stay away from the battery.
Perhaps this is a small advantage, but Apple is known for squeezing the last engineering advantage out of the design to keep the Apple experience going. (
Still, the battery for the new iPad is built in
In the hot hanger, the sensitivity of the current Li-is emphasized
Heated ion chemistry. )
Look further along this road
Beyond the iPhone 5)
Of course, there are other ways Apple can better address this double challenge.
Blow of energy density and thermal sensitivity.
An interesting Apple patent reveals ways to package battery materials to places that are currently unusable and away from heat, such as the iPhone border
Production components.
What is more hopeful is the possible changes in battery chemistry. There are already many ongoing research and some new solutions in the market.
One of them, Li
Imide, does not produce hf, so there has been a significant improvement in thermal stability and battery life.
It also effectively makes the battery thinner by eliminating most of the thickness expansion properties of the current Li-
During the service life, the ion bag cells forced the designer to sacrifice the cavity space to accommodate expansion.
Considering the speed of development of the consumer electronics market and the difficulty of maintaining a leading position in the competition, people hope that, the iPhone 5 will represent the last time Apple will remain dominant by relying primarily on the micromation of electronics and the improvement of packaging.
IPhone 6 should have at least one breakthrough technology in it --
Probably just a battery problem.
At the same time, the iPhone 5 will squeeze the ultimate out of both phones --layer carve-
Closer and closer to us, the larger screen and the additional PCB density provide greater real estate.
There will be more areas (X*Y)
The battery is in the best proportion for energy efficiency.
If Apple wants to keep the same running at least, it\'s necessary --
As I think they have to, 4 S for each iPhone charge.
All of this suggests that even with a higher size, Apple may be able to successfully further reduce the size of the new iPhone
Capacity battery, thanks in part to the best X-
Carved Y ratioout design.
This also means that, thanks to the larger screen size and the larger battery to meet the dizzying graphics performance and the better app response Apple users expect, the phone will have a heavier upgrade trigger.