350A+ current limiter
8p78S cells =624 

How to choose charge limit and discharge limit?


The speed by which a battery can safely be fast-charged is governed by only by temperature (with a 10'C rise) but datasheet defines nominal values
Hence diode thermal sensing is essential and thermal resistance to inner cell core worst case cell temp difference  to sensor must be specified. 


This can be predicted by measuring the cell ESR initial, but it rises rapidly with low SOC and slowly with each use cycle. 
Capacity and ESR improves with higher temp but aging is faster and risk is higher if temp duration is extended >5min.
Exposure to humidity and heat will shorten life; 
10% swelling from internal gassing from self-heating indicates cycle EOL or worse, pressure induced cell rupture can cause high risk fires.
gaps are critical

cell capacity is a complex function of Voltage, Current, Temperature and Coulomb counting. 


Samsung Specs:  INR18650-25R  Version 1.0 Mar. 2014

Nominal 0.2C capacity: 2,500mAh ( if used as follows);
  ... (implies 4 hr rate @ 625mA)
Charge: 1.25A CC, CV 4.20V,  125mA cut-off (10% CC),
Discharge: 0.2C, 2.5V discharge cut-off,
Rapid charge: 4A CC, CV 4.20 ± 0.05 V, 100mA cut-off (2.5% CC)
Charge Time:  Standard: 180min , Rapid: 60min (at 25℃)
Max. continuous discharge:  20 A (@25℃), 60% at 250 cycle
Weight: 45.0g max
Size:  (max) 65.00 mm H x 18.40 mm D
Temp Charge : 0 to 50℃  (recommended recharge release &lt; 45℃)
Temp. Discharge: -20 to 75℃   (recommended re-discharge release &lt; 60℃)
Temp. Storage * : 1.5 year -30~25℃, 3 months -30~45℃, 1 month -30~60℃
  * only if kept at 50% SoC then > 90% recovery


There are double layer electric properties ( multiple RC equivalent internal circuits) which give rise to a short term memory effect to surge load and voltage rise when released. 
Each ESR C value function of total capacity and the reason why capacity drops going from discharge rates of 1C to C/50 .
but specs only apply to 0.2C discharge rate


If used as Samsung specifies. at 0.2C rate, I calculate C (equivalent) = 500 Farads @ 3.6Vavg  







simulate this circuit &ndash; Schematic created using CircuitLab



Current sensing per string is easy 
Ultra-fast charging should only be applied at a moderate temperature.
The charger should limit the time the cell stays at elevated voltage.



Cannot be ignored

Anyone playing with large LiPo pack designs, ought to know Samsung's cardinal Rules.


DO NOT USE WITH E-CIGARETTE, VAPORIZER, OR SIMILAR DEVICE
DO NOT STORE LOOSE OR IN A POCKET, PURSE, ETC. ALWAYS USE A PROTECTIVE CASE OR BOX FOR STORAGE AND TRANSPORT
WHEN NOT IN USE, ALWAYS STORE LITHIUM ION BATTERIES IN THE PROTECTIVE CASE/BOX IN WHICH BATTERIES WERE DELIVERED
Misusing or mishandling lithium ion batteries can pose a SERIOUS RISK of - personal injury or property damage
BATTERIES MAY EXPLODE, BURN, OR CAUSE A FIRE IF MISUSED OR MISHANDLED
Usage of batteries is AT YOUR OWN RISK!
ONLY use with proper protection circuitry
DO NOT short circuit intentionally or unintentionally
KEEP AWAY from metal/conductive objects to prevent short circuiting
DO NOT use if PVC wrapper or terminal insulator is damaged or torn
DO NOT use if battery is damaged in any way
DO NOT over-charge or charge above the maximum voltage rating
DO NOT over-discharge or exceed the continuous discharge rating
DO NOT modify, disassemble, puncture, cut, crush, or incinerate
DO NOT expose to liquids or high temperatures
DO NOT solder onto battery, spot weld only
DO NOT use force to install or install in reverse/backwards
ONLY use within manufacturer’s specification
KEEP AWAY from pets and children
ALWAYS charge in or on a fire-proof surface and never leave batteries charging unattended
ONLY use a smart charger designed for this specific type of battery
DO NOT mix and match brands and models, old and new, used and unused batteries
STOP immediately if while charging/storing/using the battery it emits an unusual smell, feels hot, changes color or shape, or appears abnormal in any way
It is your responsibility to determine that your charger or device is functioning properly
If exposed to battery electrolyte, flush with water immediately and/or immediately contact a physician or emergency services
DO NOT throw away in trash; contact your local jurisdiction for proper recycling or disposal