Rumor: iPhone 15 may use longer-lasting stacked batteries

AppleInsider

The iPhone 15 is rumored to use a "stacked battery" that could result in lower heat and a better overall battery life.

Renders of the iPhone 15 Pro

Battery technology advances often result in devices having more power available to use, among other improvements. According to one leaker, it seems the iPhone 15 will benefit from one major technological change.

Prolific Android leaker "@RgcloudS" posted a tweet about stacked battery development in Samsung devices, but also passes comment on Apple. While Samsung's "on track" to introduce a stacked battery for smartphones, the leaker writes "Apple used it on entire iP15 lineup," referencing the iPhone 15.

If true, this could result in a number of benefits to the iPhone 15 range when it comes to power, including faster charging, higher capacities, and a considerably extended battery life.

1/3
Stacked battery is on track, but limited

Most likely only for 24U & 24+
or just 24U

meanwhile,
apple used it on entire iP15 lineup

24U & 24+ have "rated" 5000 MaH

But 24U stacked structure is different
to make it cooler, they applied cooling gel. for 65W & stability https://t.co/8khM2oAToc

-- RGcloudS (@RGcloudS)

July 12, 2023

The leaker doesn't go into detail about Apple's own batteries but does discuss Samsung's prototype samples. Samsung's apparently still waiting for stacked battery equipment to arrive at a plant owned by subsidiary Samsung SDI.

What is a stacked battery?

A stacked battery is a specific method of producing battery cells, or at least in how the elements of a battery are assembled and packaged.

A battery is made up of positive electrodes and negative electrodes, produced in long strips. In a typical battery cell, these are rolled up in a "winding" process before being packaged.

A stacked battery cell instead uses the elements as well as separators, but folds them into zig-zagging layers instead of a roll., in what is referred to as lamination.

A stacked battery can be more dense than a wound battery [Grepow]

By using folded layers instead of a roll, the packaged cell has less wasted space compared to a wound cell, so more material is included and therefore it offers a higher capacity.

The layered construction also means the battery works as a multi-pole battery rather than a single-pole wound battery. This allows there to be less resistance in the battery itself, so there is far less heat generated when it is charged or discharged.

The heat is also generated more uniformly throughout the cell, instead of being focused on a single area. Spreading the heat across the battery means it won't get worn out as quickly compared to wound battery cells, extending its life.

The stacked battery is also capable of being charged and discharged at far higher rates. This equates to faster charging of devices, as well as the potential for those devices to draw more power from the battery if required.

While a relatively new technology for smartphones, the technology has already shown some promise in another field. It is commonly used to produce batteries for electric vehicles, a device that needs to massively draw power and to recharge as quickly as possible, and benefits greatly from higher densities.

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Skeptical

I heard they’re  using cold fusion. 

melgross

DeWalt introduced stacked batteries for their power tools a bit over two years ago. I have a 1.7 amp hour one and a 5 amp hour one. I don’t know anything about the ones proposed for phones, but the ones for power tools are replacing conventional cylindrical cells. So they’re smaller. But more importantly they have greater power draw. If a tool is designed for it, it can output a fair amount more power. Sometimes more than a third more. I can tell you from my own experience with them that it’s true.

but a phone isn’t an electric motor. And this isn’t replacing a battery of cylinders as it is in power tool batteries. So it’s hard to say what the difference will be. I don’t expect more than a modest improvement from this.

radarthekat

Skeptical said:

I heard they’re  using cold fusion. 

Apparently the future is fold fusion.  

h4y3s

Hi Mel. Appreciate the comments. I would speculate that the benefits will come as faster charging and a battery that lasts a few more years. (Just armchairing it)

Draco

Your schematic of a stacked battery is incorrect. You can't make bend radii that small without causing cell shorts. 

A stacked battery is made from individual bi-cells stacked, with tabs welded together at one end. Apple has been using both wound and stacked batteries for years, even in the iPhone. All other things being equal, the stacked design does have some advantage in terms of lower impedance which helps enable faster charging. 

melgross

h4y3s said:

Hi Mel. Appreciate the comments. I would speculate that the benefits will come as faster charging and a battery that lasts a few more years. (Just armchairing it)

Well, the PowerStack batteries that DeWalt sells have the same amount of amp hours, they can just deliver them faster. Charging is about the same, but for power they oils we have 15 minute fast chargers, and have for years. They haven’t been around long enough to judge how long they’ll last. It would be nice if the lasted longer, but who knows? A lot of Apple’s batteries last 1,000 charges to either the industry 70% level, or an 80% level. I forget which. That’s pretty good. Mt 14 Prp Max was bought the first day and the battery is still at 100%.

melgross

Draco said:

Your schematic of a stacked battery is incorrect. You can't make bend radii that small without causing cell shorts. 

A stacked battery is made from individual bi-cells stacked, with tabs welded together at one end. Apple has been using both wound and stacked batteries for years, even in the iPhone. All other things being equal, the stacked design does have some advantage in terms of lower impedance which helps enable faster charging. 

True. That’s the way it’s done in the power tool industry. I don’t see a major difference here.

bestkeptsecret

The speculated Red iPhone Pro Max looks more like the Zune Brown... I'll probably just buy the standard White one. 

melgross

bestkeptsecret said:

The speculated Red iPhone Pro Max looks more like the Zune Brown... I'll probably just buy the standard White one. 

I don’t think it will look anything like that.

gnuloki

melgross said:

but a phone isn’t an electric motor. And this isn’t replacing a battery of cylinders as it is in power tool batteries. So it’s hard to say what the difference will be. I don’t expect more than a modest improvement from this.

The whole battery gate fiasco where CPU speed was throttled due to the aged batteries being unable to deliver enough power is your difference. By boosting power levels that can be safely delivered this will effectively extend the lifetime of the battery.   

melgross

gnuloki said:

melgross said:

but a phone isn’t an electric motor. And this isn’t replacing a battery of cylinders as it is in power tool batteries. So it’s hard to say what the difference will be. I don’t expect more than a modest improvement from this.

The whole battery gate fiasco where CPU speed was throttled due to the aged batteries being unable to deliver enough power is your difference. By boosting power levels that can be safely delivered this will effectively extend the lifetime of the battery.   

Maybe, maybe not. When flatpack batteries allow higher discharge rates they do it at the expense of battery charge life. In other words, if a battery can deliver a third more energy at any given moment, it shortens the time between recharges. No matter what, the charge the battery stores remains the same. A 4,000 milliamp battery is still a 4,000 milliamp battery.  This really has nothing to do with the overall lifetime of the battery, just how much output it can deliver at any moment.

there are batteries that already have longer lifetimes. Apple uses them. Most batteries have a 500 full recharge rating. Some of the products Apple has uses batteries with a 1,000 full recharge rating. It’s the type of lithium that determines that. For example, for automotive use, batteries are designed to have less power capacity in exchange for a massive amount of full recharge cycles. Also, most auto batteries, such as those Tesla uses are not stacked, but cylindrical, despite what is being said. Some are of other configurations.