4680, the new battery cell form factor is here. And we believe we’ve found the specs of the first cells being produced. Any upcoming, improved battery chemestries can also be used in these cells for improved energy density. So, this a big deal for emtbs? Well, not really.
forgive me I might not get this right but i had checked out the 4680 specs a while back and IIRC the advantages aren’t based on density but the chemistry, charge/discharge rates and improved thermal properties. as well as that there was the way the cells were connected together to form the battery with anode/cathode-less form factor so there will be less losses.. there theres the change to nickel from cobalt..
Im only interested in this because im waiting for lifepo4 batteries etc to ‘get there’ and enable me to go off grid.. ebike battery improvements are a bonus :p
Yes and No.
It will be a big heavy battery with 1000ish Wh. The BMS will be easy as it will only be 10 batteries. Overall it won’t be a revolution, just another similar speced battery.
Hmmmmm I wonder if this is the cell YT are working on for their 700WH battery.
[QUOTE=”Neloz, post: 373341, member: 19567″]
Hmmmmm I wonder if this is the cell YT are working on for their 700WH battery.
[/QUOTE]
No. It’s imposable to make a 700wh battery with them. 4680 will be at least 25amp hours per battery.
Better news for cars and bigger packs for solar/wind etc. storage.
I also was under the impression that the advantages to Tesla’s 4680 cells, were predominantly due to slimline construction, & a bit of thermal advantage from putting the connector heat at one end of the cell, on the idea it’s easier to bleed off that way?
Personally, I like big cells. I want to see them used on everything from ebikes, to robots, automobiles, aircraft, power tools, & USB batteries.
In practical terms, I don’t know of many ebike battery case dimensions which would currently accommodate 4680s very efficiently…? I’m trying to picture a Dorado style car using 4680 cells, & I’m not sure the geometry works out to an efficient use of space?
’Dorado style battery’
≠”Dorado style car”
[QUOTE=”Neloz, post: 373341, member: 19567″]
Hmmmmm I wonder if this is the cell YT are working on for their 700WH battery.
[/QUOTE]
LOL, YT promising 700W for years, face it, they were just lying through their teeth. Even IF they finally come out with a larger battery, they duped a lot of people into buying Decoys based on untrue speculation.
[QUOTE=”Alexbn921, post: 373220, member: 20456″]
Yes and No.
It will be a big heavy battery with 1000ish Wh. The BMS will be easy as it will only be 10 batteries. Overall it won’t be a revolution, just another similar speced battery.
[/QUOTE]
The BMS would be exactly the same. BMS’s monitor only the parallel groups, not each cell in a parallel group.
A 10S1P battery has the same number of monitoring “wires” as a 10S2P pack.
Not much changes until the chemistry allows for an energy density increase.
A minor point, but energy density can also be calculated on the basis of energy per unit volume of the finished (complete) battery in the bike/car/etc. I understand the importance of measuring energy density on the basis of mass and agree that must have primacy for several reasons in cars and bikes etc.
But, it would be interesting to know from those here who are good at maths (not me!) what their opinion is about the difference in final volume (and hence energy/volume density) of a complete battery with these new cells compared to the other traditional cells when arranged in three columns of cells and 4 columns of cells. Anybody got the time, inclination and know how for that please?
What got me thinking about this was a consideration of down tube volume and centre of mass for a completed e-bike as part of a complete consideration of which battery cell is best in which situation for an ebike. Looking at the Tesla flat battery pack travelling low in the chassis make my point well, where the issue is the volume of space (air) between the old and new cells.