Lightweight XCell LFP cells - Wanted: Verification of Capacity

[Johan]

Summary
LFP cells from XCell seem to be transcendentally epic in terms of mass energy density (Wh/kg). Has anyone measured the actual maximum capacity and the mass of any cell from XCell? I wonder if the specs from this factory are met in practice and whether they are still as safe as expected from LFP chemistry.

Problem context
Which batteries or cells to choose when designing for a combination of minimum weight and "plenty" of safety? Due to space restrictions, I probably need individual cells.

Analysis
Minimizing weight calls for the comparison of energy mass densities. In general, for the "safe" LFP batteries, it is

• 90 to 110 Wh/kg according to Wikipedia [1],
• 90 to 120 Wh/kg according to BatteryUniversity.com [2].

For example,

• Battleborn: 100Ah x 4cell x 3.2Vnom / 14.1kg = 91 Wh/kg (price: ~$741/kWh) [3].

LFP cells are higher because they do not include the mass of: BMS, heat sink, casing, handles for lifting, etc. (see for example Will opening a Ruixu).
Now check out this cell,

• XCell: 277Ah x 3.2Vnom / 5.6kg = 158 Wh/kg (price: ~$360/kWh) [4].

Now that is not just a little bit, but WAY higher, i.e. 32% higher than the largest range upper limit of 120 Wh/kg from [2].
For comparison,

• Tesla Model S module: 5.2kWh / 24.9kg = 208 Wh/kg (price: ~$200/kWh) [5].

Now that is remarkable! The XCells have a mass energy density that is 76% of the Tesla Model S module. That is getting awfully close. And the race is still going. Of course, a BMS etc must still be added, but let's assume that that weight is negligible, for the sake of conversation.

Question
Can Anyone confirm the XCell maximum capacity?

References
[1] https://en.wikipedia.org/wiki/Lithium_iron_phosphate_battery
[2] https://batteryuniversity.com/learn/article/types_of_lithium_ion
[3] https://battlebornbatteries.com/shop/12v-lifepo4-deep-cycle-battery
[4] https://www.electriccarpartscompany.com/Lithium-Battery-277Ah-LiFePO4-XCell
[5] http://store.evtv.me/proddetail.php?prod=esp32bms (open the user manual PDF)

Keywords: LiFePo; LiFePo4; X-Cell; mass; weight; minimum

 

[electric]

LFP manufacturers have been making strides in energy density, I bet the Wiki article needs an update.
Of course you can't compare cell density with battery density, too much loss in packaging, BMS, etc.

Also, larger cells have better density because internal stuffing of active materials is better in larger cells than smaller cells, for same reasons, packaging, terminals, etc. So even comparing naked cells you should compare them in similar AH sizes.
Another factor is cylindricals vs. prismatics. Cylindricals leave gaps between cans, not the best use of volume. Look at the videos of Battleborn internal design, there is a lot of air in there, as they use small cylindrical cells.

 

[electric]

Here is a point of reference from CALB, reputable LFP supplier http://www.calbusainc.com/additional-information/
Look at the bottom of the page for specs and downloads.

 

[Johan]

Update: I may be wrong [edit: I am - thanks @electric], but XCell seems to be a rebranded cell from the factory named BLS in Shenzhen, China, also rebranded all the time by e.g. [1,2, and 3].

[1] https://www.vpwllc.com
[2] https://www.lithiumstorage.eu
[3] http://www.lithium-batterycells.com

 

[electric]

BLS is not a cell manufacturer, they take OEM cells, drill/tap terminals, re-brand them and sell retail.
OEM does not sell direct to small customers, OEM makes millions of cells for EVs and large storage projects.
These are most likely B grade cells, which OEM sells at a discount. Nothing wrong with B grade for DIY projects, they just don't pass muster when critical cell matching is required in large projects.

 

[Steve_S]

OEM = Original Equipment Manufacturer.
VAR = Value Added Reseller

Assuming that anything not sold directly by an OEM is a lesser grade or defective is pushing reality off the edge.
IF you are particularly interested in a specific "Brand / Make", you can often contact the manufacturer for a list of Authorized / Approved list of vendors / suppliers & resellers (whichever is appropriate).

BTW, there are sheister's doing business in every nation / continent and their Nationalities. Religions, Colour, Gender etc have absolutely no bearing on miscreants and their scams, they exist only to rip people off.

 

[electric]

OEM = Original Equipment Manufacturer.
VAR = Value Added Reseller

Assuming that anything not sold directly by an OEM is a lesser grade or defective is pushing reality off the edge.

Completely agree with you. B grade does not mean defective, it just means lesser spec than required by main volume customer.
For example, if the cell is 1AH less or 0.1mOhm more than the strict spec provided by volume customer, this cell will be sold to a smaller VAR as B grade cell, which is still a perfectly good product for DIY projects at a lower cost. Everyone wins.
But there are many VARs and each one could be honest or dishonest, so buyer is always at risk and should watch out.