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Thread for new battery breakthrough PR releases

So this is a bit interesting, assuming they didn't fake it by wiring cells in series inside a pouch cell. Video shows how they can build cells at different voltages. Each layer would be .55V if the graphic is accurate.

 
JRP3 said:
So this is a bit interesting, assuming they didn't fake it by wiring cells in series inside a pouch cell. Video shows how they can build cells at different voltages. Each layer would be .55V if the graphic is accurate.

Click to expand...
How is balancing possible? Will all the layers stay the same voltage all the time?
 
ak136 said:
How is balancing possible? Will all the layers stay the same voltage all the time?
Click to expand...
Balancing is possible because everything is matched from the factory and thermals are essentially identical.

Bi/multipolar cells are the holy grail of pack building since they make stuff so much simpler, higher performance and lower cost.
 
BlueSwordM said:
Balancing is possible because everything is matched from the factory and thermals are essentially identical.

Bi/multipolar cells are the holy grail of pack building since they make stuff so much simpler, higher performance and lower cost.
Click to expand...
This not correct. What you want to say is "balancing is not needed". Not that it is "possible".
And even this is not correct: You still could have small differences in size, loading, porosity of the electrodes etc. resulting in differences in capacity, finally resulting in debalancing of single electrode stacks. Further thermal imbalances could still occur.
So yes, it could make things easier for pack building, but glorifying it too much neglects reality.
 
Aeffle9 said:
And even this is not correct: You still could have small differences in size, loading, porosity of the electrodes etc. resulting in differences in capacity, finally resulting in debalancing of single electrode stacks. Further thermal imbalances could still occur.
Click to expand...
Agreed.

Then there is the varying loss of lithium from electrolyte-electrode interphase layer formation in each cell element, also affecting capacity. Minimal, but there.

A bigger issue IMO is the different self-discharge (for each cell element) due to non-ideal behavior of the solid electrolyte, contamination, physical defects, etc...unbalancing inevitably occurs. It could be a lot slower than seen in standard li-ion cells, but it’s there, happening 24/7.
 
There's a lot of tool packs like DeWalt, Milwaukee, etc. that get away without balancing for years. So it does seem vaguely possible to do without just by matching the cells well at the factory.

Of course, those companies profit from the packs dying earlier than they would otherwise and the customer buying a new one. So it does sort of fall into the planned obsolescence category more than forgoing unneeded hardware to have more room for capacity category.
 
same for bosch. seen some unbalanced packs which died because of single cell failure, but balancing wouldn't help.
 
freesty said:
same for bosch. seen some unbalanced packs which died because of single cell failure, but balancing wouldn't help.
Click to expand...
How it wont help? In a pack if you have a weaker cell with lower capacity it will be the first one to reach 4.2V and also when discharging will be the first one to reach 2.5V. Therefore the weaker cell gets more cycles and becomes weaker and weaker and at failure it looks like a single cell sudenly died
 
lnanek said:
There's a lot of tool packs like DeWalt, Milwaukee, etc. that get away without balancing for years. So it does seem vaguely possible to do without just by matching the cells well at the factory.
Click to expand...

This has been the case with both my em3ev batteries and RC Lipo packs that got cherry picked and matched by capacity + IR with the help of an icharger.
 
ak136 said:
How it wont help? In a pack if you have a weaker cell with lower capacity it will be the first one to reach 4.2V and also when discharging will be the first one to reach 2.5V. Therefore the weaker cell gets more cycles and becomes weaker and weaker and at failure it looks like a single cell sudenly died
Click to expand...
yeah, and now think, how balancing would help, or not. the weakest cell will get the most stress anyway.
 
freesty said:
yeah, and now think, how balancing would help, or not. the weakest cell will get the most stress anyway.
Click to expand...
If we talk about passive balancing then yes passive balancing will punish the weakest cell even further, but there is active balancing also
 
lnanek said:
There's a lot of tool packs like DeWalt, Milwaukee, etc. that get away without balancing for years. So it does seem vaguely possible to do without just by matching the cells well at the factory.

Of course, those companies profit from the packs dying earlier than they would otherwise and the customer buying a new one. So it does sort of fall into the planned obsolescence category more than forgoing unneeded hardware to have more room for capacity category.
Click to expand...
Those packs have tons of issues with early deaths so even with great matching you will have problems, but they do last longer than you'd think.
 
freesty said:
yeah, and now think, how balancing would help, or not. the weakest cell will get the most stress anyway.
Click to expand...
This is only true if the root cause of debalancing is varying capacity (either from the start right away or due to higher stress on one cell for whatever reason) among cells. There are also other reasons for debalancing like different temperature, different resistance or different self-discharge rate of cells. For the latter cases, balancing helps a lot to prolong the life time of a pack.
 
we are talking about power tool packs, with amount of max 20 cells usually. they heat up pretty homogeneous. DCIR and self discharge should and is done by high production quality in mass production.

when packs gets bigger, sure passive top balancing is necessary, but mostly to allow higher charge rate near 100%.
 
The last power tool batteries I bought did cost 15€ including a charger. (Einhell 18V, 2,5Ah pack).

There is no point in adding a 50A BMS with active balancing to that.

++++++++++

Anything new from the 18650 and 21700 world?
 
Cephalotus said:
The last power tool batteries I bought did cost 15€ including a charger. (Einhell 18V, 2,5Ah pack).

There is no point in adding a 50A BMS with active balancing to that
Click to expand...
How they deal with overcharge? Isnt that a fire risk? A big disbalance can cause one of the cell to go over 4.2V
 
BatteryMooch said:
There’s been an almost constant stream of new 21700 releases for thr past couple years and a few 18650 releases too. And several of both in the works too.
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For example the Molicel P30B is available. I assume it is roughly comparable to the P50B in 21700 size. Molicel has a roadmap for future 21700 cells up to the magic P85, but I don't know about something comparable in the 18650 size. This is the same with all manufacturers. I use the LG MJ1. This cell is from 2014. Still nothing newer here?
 
Cephalotus said:
something comparable in the 18650 size. This is the same with all manufacturers. I use the LG MJ1. This cell is from 2014. Still nothing newer here?
Click to expand...
Ampace JP30p1, EVE 30PL and TenPower 30XG are all amazing 18650 power cells with 3000mah nominal ratings. Ampace and EVE cells look to be pretty widely available.

I am using the JP30's in a vaccuum cleaner for a significant increase in performance and run time. Also use one in a single cell flashlight which now stays far cooler and can maintain higher brightness for longer, as I use it.

Excluding the vapcell offerings, the Amprius SA110 looks to be a good energy 18650 cell with a 4000mah nominal rating.
 
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