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Researchers Create Sodium Battery In Industry Standard "18650" Format (gizmag.com)
Zothecula sends word that a French team has developed a battery using sodium ions in the usual "18650" format. Gizmag reports: "A team of researchers in France has taken a major step towards powering our devices with rechargeable batteries based on an element that is far more abundant and cheaper than lithium. For the first time ever, a battery has been developed using sodium ions in the industry standard "18650" format used in laptop batteries, LED flashlights and the Tesla Model S, among other products."
It seems like we're getting announcements about revolutionary world changing never seen before astounding new battery designs every day, but nothing ever comes to market.
Maybe it's time to question what the fuck is wrong with the shitty "journalism" that tries and make huge stories out of nothing.
Using sodium ions?
So, they would be (re)charged with "a salt in battery"?
The idea on many small battery cells is that the standard size makes them available from multiple suppliers, reducing risk, and the gaps between the cells due to the packing fraction provide a conduit for cooling.
Telsa does have a lifecycle plan to refurbish packs from cars for use in the home; at least in the press photos, the home packs are a different form factor, so I wonder if they break up the packs to cull outright broken cells and then reconstitute the good ones into wall units. Since the breakdown is a function of electrode area, having the area in smaller pieces might help with reuse.
"Because Science" is one step from "Because old book". Try "Because of my experiment testing my falsifiable assertion".
If you want an actual answer instead of just an excuse to bag on Tesla ... Smaller cells have more surface area to dump heat, which is crucial when recharging. In other words, the mass of the casing (which is not large) is actively being used for thermal management. Additionally, in the manufacturing process, smaller cells have a lower reject rate and allow both a much more repairable battery pack than custom cells and improve the performance as cells degrade. The packing density for these cells is pretty good, (85%) and smaller cells allows tailoring to custom shapes, though Tesla doesn't take advantage of that, having roughly rectangular packs.
Lithium is about as abundant as chlorine. Concentrated deposits occur all over the world with proven reserves of about 14 million tonnes and annual production of 36,000 tonnes. It would be really hard to run out (or create scarcity) of lithium.
I don't read your sig. Why are you reading mine?
Assuming a linear-ish discharge curve over a 70% discharge, 1.44Wh D cell to 18.5Wh (equivalent) C cell is not a 2x capacity increase.
I want battery technology to increase an order of magnitude every year too, ... but come on. We've made enormous strides.
You, yourself, can buy low-resistance, low-self-discharge lithium ion batteries at 250Wh/kg. And they're cheap. Compare that to 30Wh/kg NiCD batteries of 30 years ago.
A government is a body of people notably ungoverned - AC
More importantly, the 7000 little batteries actually make the system more efficient than 7 large ones. Because of the massive amount of power the motors have (50+ kW), using more cells in series means higher voltages. And higher voltages means lowered currents which mean less wasted power in IIR losses. Double the voltage, halve the current, one-quarter the loss. It's why transmission lines are high voltage, why data centers usually get 208V or higher (besides three-phase) at the racks, etc.
7 lithium batteries only gets you 28V. If we use 56kW, that's nearly 2000A you have to draw - you probably will have to use the chassis split down the middle to carry that kind of current. 7000 lithium batteries as 7x1000 (4000V) series packs means drawing 14A from each pack, or 98A total. Of course, no one runs that high a pack voltage - safety reasons - it's usually closer to 480V or so, which is a large current but still manageable.