While 99% of the tablets out there are all fully symmetrical devices, I’d like Eve to shake things up a bit.
Asymmetrical design means one side of the device is not a mirror of the opposite side. While no tablet is fully symmetric (otherwise you’d have two power and volume buttons), in term of weight distribution and dimensions, they are fully symmetrical.
Note that asymmetrical is not something totally new. Some tablets have existed with this design, namely the Sony Tablet S and Lenovo Yoga Tablet
Xperia Tablet S
Lenovo Yoga Tablet
As you can see on both those devices, if they are laid flat on the table, the screen does not lay flat, instead it forms an angle. That’s a pretty good indication that the design is asymmetric.
To fully understand the benefit, we need to talk about the concept of weight distribution and the basics of lever.
As you can see in the GIF above, the closer the center of mass to the lever, the lighter it feels. It translates directly to when you are holding the tablet as well.
The heaviest component of a tablet is the battery (excluding the display, of course, which cannot be moved anywhere), so in this case it makes sense to move it as close as possible to your hand to minimize the distance.
Or to take an extreme example, imagine holding the Lenovo tablet above, but from the thin side, I am sure it would be much harder to hold, due to the lever effect above.
The second benefit is the lower center of mass when you prop up the kickstand. To understand this, we need to go back to high school physics again, mainly the tipping point.
Have you ever wondered why a Jeep has much higher body roll than a Ferrari? This is the reason! Having the center of mass as low as possible is critical in a car, which is why electric cars generally handle better than a gasoline car of the similar class, due to the battery being mounted right on the floor of the car, instead of the engine.
Back to tablets, remember how people are complaining that detachables feel top-heavy when used as a laptop? This is exactly why. Generally laptop’s center of mass is around 0.4 inch / 10 mm above the ground, while a 2-in-1 like the Surface Pro or Eve V in laptop mode can easily reach 2-4 inch / 50-100 mm, depending on the kickstand angle, or up to 10x.
As you can see, the tablet with lower center of gravity will not tip over, even on extreme angle. It will give the user a sense of confidence in handling the product
Here is another magic of low center of mass in roll over test…
Enough with the physics, now get to economics.
While most tablet batteries now use non-standard form factors or shapes, some even come in exotic terraced system, standard cylindrical batteries are almost a commodity item. You can find it on (older) laptops, battery banks, all the way to Tesla vehicles.
Inside every Tesla vehicle, there are thousands of laptop battery cells inside. Pictured is the Tesla Model S 70/70D (70 kWh)
And there is a good reason why Tesla chose this battery, it has the cheapest $/kWh rating, which allows Teslas to reach further range than any other electric car. Like seriously cheap, you can get one cell for less than $5. Smart move, Elon!
In addition, it also has the highest density among other form factors, since the form factor is already well-researched.
The most popular battery cell size is no doubt the 18650 form factor, where the name comes from the 18mm diameter and 65mm height. It also the battery used in the Lenovo and Tesla above.
Alternatively, there is the new type 2170 or 21700 with 21mm diameter and 70mm that’s used in the Tesla Model 3. It has even higher density at the size that virtually feels similar.
With that in mind, I designed the concept with 23 mm thickness on the thickest part (21700 battery), to account for worst-case scenario. For the concept, I used 10" form factor, but you can easily scale it down to 8" or up to 12-13"
Oh one more thing, the space next to the battery, which is still around 15mm thick, can be used to store the pen. How about that? Finally a pen can be stored in the tablet!
The 21700 cell is the most interesting one due to its density of up to 18.5 Wh per cell. On a 10" tablet, you can fit up to three of those cells for a total capacity of 55 Wh, 15% larger than the V, and larger virtually any tablet out there. Remember, this is on a 10" tablet that’s just as big as the non-Pro iPad.
Despite the extra capacity, the weight of 69gr would total to just 207gr, or approximately the same as the battery on the V.
With 18650 cells, you could get up to 3.5 Ah per cell, which means 13 Wh per cell. That still gives you a decent 39 Wh for a 10" tablet (3 cells), still larger than 32 Wh in the iPad and 28 Wh in the Surface Go. On the other hand, we could get 52 Wh on a 12" tablet (4 cells). The weight is around 48 grams per cell, so 144 grams for 3 cells (10") or 192 grams for 4 cells (12")
tldr: By mounting a standardized cylindrical cells on the edge of the tablet, instead of the standard rectangular cell around the center, you could get these benefits
- Feels lighter to hold with one hand
- Less top-heavy in laptop mode
- Higher battery capacity
- Lower battery cost
- Pen storage
- Possibly also easier to design the product with removable battery in mind.