There are 3 different 30Q
The top 30Q is made in Korea and can not read the manufactured date
The middle 30Q is made in Malaysia and can not read the manufactured date
The below 30Q is made in Tianjin ,China. That’s why it with “T ”at the end of date code “KF5T” .
K means 2020/F means March/5 means fifth week/T means Tianjin factory
There are 3 different 30Q
The top 30Q is made in Korea and can not read the manufactured date
The middle 30Q is made in Malaysia and can not read the manufactured date
The below 30Q is made in Tianjin ,China. That’s why it with “T “at the end of date code “KF5T” .
K means 2020/F means March/5 means fifth week/T means Tianjin factory
I have a question / need clarification regarding the 2nd letter of the date code for 30Q6-T battery, which you mentioned are manufactured in Tianjin, China.
What’s the earliest year the 30Q6-T are made? If “K” means 2020, then “J” means 2019, and “L” will mean 2021, is this right? (so far I’ve only seen “K” as the 1st lettter of the 30Q6-T, but we’ll likely see 2021 (ie. start with letter “L” for 2021, sometime soon)
2nd letter “F” means March : So January would be “D”? and December would be “O”?
(so far I’ve got a 30Q6-T that’s labeled KH1T and another 30Q6-T labeled KK2T,
this would mean: KH1T = 1st week of May 2020, and KK2T = 2nd week of August 2020 ?)
Purchased ten 30Q6 KH1T about this same time last year for $50. Used them to replace ten 30Q 141 cells (36V battery pack) suffering from high self-discharge (after 125 cycles).
Just tested all 30 cells again after another 125 cycles this year. Six more of the remaining twenty 141 cells have to be replaced due to high self-discharge. The GOOD News is that all of the 30Q6 KH1T are holding strong.
Can’t find even one world-wide supplier that currently stocks the newer improved 30Q6 … what’s up with that ?? Not even the 30Q 141 is curreently available from distributors in: USA, Europe or China.
Is the unavailability and price increase due to inflation with the price hike ($4.50 to $9.00). The only ones currently available are the older 136 / 138 and their price has doubled.
I just saw this post after ordering 2pcs samsung 30Q from vapcell aliexpress store.
So which version I’m getting 
Industry demand is through the roof. Car makers, ebikes, power tools, etc. are buying all the batteries the factories are churning out. Our usual resellers can’t get their hands on the supply. Add to that many of the bigger factories are switching more and more to 21700 or other larger formats, again mostly because of industry demand.