Article 4680 battery cells, good news for emtbs?

dobbyhasfriends

🌹Old Bloke 🎸
Subscriber
Sep 19, 2019
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Llandovery, Wales
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
 

Alexbn921

Well-known member
Sep 27, 2021
545
506
East Bay CA
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.
 
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?
 

squeegee

Well-known member
Aug 19, 2019
360
267
USA
Hmmmmm I wonder if this is the cell YT are working on for their 700WH battery.
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.
 

randycpu

Member
Nov 15, 2018
85
39
Silicon Valley, USA
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.
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.
 

Coolcmsc

Well-known member
Oct 29, 2019
525
473
U.K.
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.
 

Waynemarlow

E*POWAH Master
Dec 6, 2019
1,054
868
Bucks
I can't see any benefit of the larger 4680 cells mainly due to their form and with the new pouch cells ( allowing much smaller odd shapes ) starting to appear.
 

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