BQ40Z50-R1: How much impact does OCVFR have?

Hello

1. The chemical ID obtained by my test is 400.

2. QMAX update of LiFePO4 is reference charging? After the end of charging, the Valid Charge Termination is satisfied. After relax, the voltage is also greater than 3400. Why isn't QMAX updated?

3. How can we ensure that the update status ranges from 06 to 0e in mass production? Is it Discharge-Charge-relax or Dicharge-Charge-DisCharge-relax?

4, how to get valid DOD0, QMAX update after discharge

5、Attached is the data of Discharge-Charge-RELAX

5775.BQ40Z50 1.log8130.BQ40Z50 2.log

Hello Wyatt,

Like the other battery I used to verify. Less than 5 hours after discharge, QMAX was updated. When charging and discharging conditions are the same, why are some updated and others not?

The OCVFR is set to 0

2# BQ40Z50.log

Hello Jingming,

There are many checks to qualify the OCV for a Qmax update, some of the conditions are private parameters that prevent erroneously updating Qmax. It will be difficult to pinpoint the exact root cause of why the log does not update Qmax without extensive data review. For LFP it is most likely relaxing back into the flat region, or too close too it, so it is disqualified until the 48 hour wait is met. You also need 2 good OCV points, if your first OCV point was not good before charging then Qmax will not update, even if everything looks correct at the end of charge.

Sincerely,

Wyatt Keller

Hello Wyatt,

1. Is there any good method to recommend?

2. If OCVFR=1, will qmax be forced to update after relax lasts for 48 hours?

3. If it can forcibly update QMAX, should it relax 48H after charging or charge-discharge?

Hello Wyatt,

May I ask why all of them are not updated to 0E after charge  - relax 4H- discharge  - relax 48H?

After relax 48 hours, some VOK=0, some VOK=1.some VDQ=0, some VDQ=1.REST is all 1. But updatestatus didn't learn the 0E

Thu Dec 01 09:20:41 CST 2022

Device Version Info = 4500_1_06
BQZ Device Name = bq40z50R1
BQZ Firmware Version = V1_06_BLD36

Design Capacity = 6700
Design Voltage = 12800
Specification Info = 0x0031
Manufacturer Date = 2022-11-25
Serial Number = 0x0005
Manufacturer Name = BST26650G2W
Device Name = BQ40Z50-R1
Device Chemistry = A0

Sample,DateTime,ElapsedTime,ManufAccess,RemCapAlarm,RemTimeAlarm,BattMode,@Rate(@),@TimeFull,@TimeEmpty,@RateOK,Temperature,Voltage,Current,AvgCurr,MaxErr,RSOC,ASOC,RemCap,FullChgCap,RunTimeEmty,RunTimeEmty,AvgTimeFull,ChgCurr,ChgVolt,BattStat,CycleCnt,TurboPwr,TurboCurr,SoH,OpStatA,OpStatB,TempRange,ChgStat,GaugeStat,ITStat,MfgStat,SafetyAlertAB,SafetyStatAB,SafetyAlertCD,SafetyStatCD,PFAlertAB,PFStatAB,PFAlertCD,PFStatCD,CellVolt1,CellVolt2,CellVolt3,CellVolt4,vBAT,vPACK,CellCurr1,CellCurr2,CellCurr3,CellCurr4,CellPower1,CellPower2,CellPower3,CellPower4,Power,AvgPow,IntTemp,TS1Temp,TS2Temp,TS3Temp,TS4Temp,CellTemp,FETTemp,FltRemQ,FltRemE,FltFullChgQ,FltFullChgE,NoLoadRemCap,TrueRemQ,TrueRemE,InitialQ,InitialE,TrueFullChgQ,TrueFullChgE,T_sim,T_ambient,RaScale1,RaScale2,RaScale3,RaScale4,CompRes1,CompRes2,CompRes3,CompRes4,PackGrid,LStatus,CellGrid1,CellGrid2,CellGrid3,CellGrid4,StateTime,DOD0_1,DOD0_2,DOD0_3,DOD0_4,DOD0 Passed Q,DOD0 Passed E,DOD0 Time,DODEOC_1,DODEOC_2,DODEOC_3,DODEOC_4,QMax1,QMax2,QMax3,QMax4,QMaxDOD0_1,QMaxDOD0_2,QMaxDOD0_3,QMaxDOD0_4,QMaxPassedQ,QMaxTime,Tk,Ta,RawDOD_1,RawDOD_2,RawDOD_3,RawDOD_4,CBTime1,CBTime2,CBTime3,CBTime4,CBDOD_1,CBDOD_2,CBDOD_3,CBDOD_4,CBTotalDODChg,SOH_FC_Q,SOH_FC_E,LogRowTime(ms),LogStatus
1,2022-12-01 09:20:46,4.003,0x0187,300,10,0x6001,0,65535,65535,1,25.8,11446,0,0,2,0,0,0,6898,65535,65535,65535,1300,14600,0x02D0,11,-7143,-7944,100,0x0187,0x0000,0x10,0x0002,0x51,0x0119,0x00F8,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,2872,2863,2855,2857,11462,11462,0,0,0,0,0,0,0,0,0,0,27.2,25.8,25.3,25.2,25.2,25.8,-273.2,0,0,6898,8958,0,68,57,6878,8826,6950,8918,26.1,25.8,1000,1000,1000,1000,0,0,0,0,14,6,0,0,0,0,62998,15917,15939,15958,15953,0,0,61,0,0,0,0,7100,7090,7094,7084,15929,15954,15964,15960,-36,1455,4.9,18000,15924,15942,15960,15956,0,0,0,0,0,0,0,0,0,6918,8982,2312,SUCCESS

Hello Wyatt,

May I ask why all of them are not updated to 0E after charge  - relax 4H- discharge  - relax 48H?

After relax 48 hours, some VOK=0, some VOK=1.some VDQ=0, some VDQ=1.REST is all 1. But updatestatus didn't learn the 0E

Thu Dec 01 09:20:41 CST 2022

Device Version Info = 4500_1_06
BQZ Device Name = bq40z50R1
BQZ Firmware Version = V1_06_BLD36

Design Capacity = 6700
Design Voltage = 12800
Specification Info = 0x0031
Manufacturer Date = 2022-11-25
Serial Number = 0x0005
Manufacturer Name = BST26650G2W
Device Name = BQ40Z50-R1
Device Chemistry = A0

Sample,DateTime,ElapsedTime,ManufAccess,RemCapAlarm,RemTimeAlarm,BattMode,@Rate(@),@TimeFull,@TimeEmpty,@RateOK,Temperature,Voltage,Current,AvgCurr,MaxErr,RSOC,ASOC,RemCap,FullChgCap,RunTimeEmty,RunTimeEmty,AvgTimeFull,ChgCurr,ChgVolt,BattStat,CycleCnt,TurboPwr,TurboCurr,SoH,OpStatA,OpStatB,TempRange,ChgStat,GaugeStat,ITStat,MfgStat,SafetyAlertAB,SafetyStatAB,SafetyAlertCD,SafetyStatCD,PFAlertAB,PFStatAB,PFAlertCD,PFStatCD,CellVolt1,CellVolt2,CellVolt3,CellVolt4,vBAT,vPACK,CellCurr1,CellCurr2,CellCurr3,CellCurr4,CellPower1,CellPower2,CellPower3,CellPower4,Power,AvgPow,IntTemp,TS1Temp,TS2Temp,TS3Temp,TS4Temp,CellTemp,FETTemp,FltRemQ,FltRemE,FltFullChgQ,FltFullChgE,NoLoadRemCap,TrueRemQ,TrueRemE,InitialQ,InitialE,TrueFullChgQ,TrueFullChgE,T_sim,T_ambient,RaScale1,RaScale2,RaScale3,RaScale4,CompRes1,CompRes2,CompRes3,CompRes4,PackGrid,LStatus,CellGrid1,CellGrid2,CellGrid3,CellGrid4,StateTime,DOD0_1,DOD0_2,DOD0_3,DOD0_4,DOD0 Passed Q,DOD0 Passed E,DOD0 Time,DODEOC_1,DODEOC_2,DODEOC_3,DODEOC_4,QMax1,QMax2,QMax3,QMax4,QMaxDOD0_1,QMaxDOD0_2,QMaxDOD0_3,QMaxDOD0_4,QMaxPassedQ,QMaxTime,Tk,Ta,RawDOD_1,RawDOD_2,RawDOD_3,RawDOD_4,CBTime1,CBTime2,CBTime3,CBTime4,CBDOD_1,CBDOD_2,CBDOD_3,CBDOD_4,CBTotalDODChg,SOH_FC_Q,SOH_FC_E,LogRowTime(ms),LogStatus
1,2022-12-01 09:20:46,4.003,0x0187,300,10,0x6001,0,65535,65535,1,25.8,11446,0,0,2,0,0,0,6898,65535,65535,65535,1300,14600,0x02D0,11,-7143,-7944,100,0x0187,0x0000,0x10,0x0002,0x51,0x0119,0x00F8,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,2872,2863,2855,2857,11462,11462,0,0,0,0,0,0,0,0,0,0,27.2,25.8,25.3,25.2,25.2,25.8,-273.2,0,0,6898,8958,0,68,57,6878,8826,6950,8918,26.1,25.8,1000,1000,1000,1000,0,0,0,0,14,6,0,0,0,0,62998,15917,15939,15958,15953,0,0,61,0,0,0,0,7100,7090,7094,7084,15929,15954,15964,15960,-36,1455,4.9,18000,15924,15942,15960,15956,0,0,0,0,0,0,0,0,0,6918,8982,2312,SUCCESS

Hello Jingming,

There are other parameters that could disqualify the Qmax from occurring, if the VDQ and VOK indicate the voltage was disqualified then something else may have happened (not a 37% change in DOD, temperature outside of 10degC to 40degC, etc).

Do you have a full log from a pack the didn't learn and one that did? The log shared only has one data entry.

Sincerely,

Wyatt Keller 

Hello Wyatt,

Two attachments, one of which is OCVFR=0 and REST=1 after discharge, this battery is not updated after cyclic test, and the board re-downloads the program.

Tanks

1# 20221201.log2# 20221201.log

Hello Jingming,

It looks like both logs show that the update status remains at 0x06 which means no new Qmax?

Sincerely,

Wyatt Keller

Hello Wyatt,

Yes, I used 50 batteries to study, only 36 of them were good, and 14 couldn't update QMAX

Please help to guide me, how should I operate

Thanks

Hello Jingming,

It looks like both logs shared it did not occur, can you also share a log of a successful pack?

Sincerely,

Wyatt Keller

Hello Wyatt,

The updated product has been sent to the customer for testing. I will run the cycle test with the one that cannot be updated. Maybe it took a little longer.

If it is not updated to 0E, what will be the impact during use?

Thanks

Hello Wyatt,

1、Besides the FCC not updating, there should be other effects, right? For example, balance doesn't turn on

2、The ID corresponding to the battery model is different from that of the GPC. Which is better? For example, the ID recommended by GPC for this battery cell is 0400, but the cell model corresponds to 4100.   My other cell GPC recommended 2437, but the cell model corresponding ID is 5820

Hello Wyatt,

I would like to ask you. I set FCSETV=1, but due to the battery consistency problem, the battery did not enter the constant voltage stage. VCT=0 after full charge, but FC=1. Will VCT=0 cause QMAX not update?

Sincerely,

Hello Wyatt,

I took a new battery to test, but several cycles, QMAX has not been updated. I really can't find the reason. Is it because of the high pressure difference of the battery?

X4s8a 20221216.logBQ40Z50 1219.gg.gg.csv

Hello Jingming,

It looks like OCVFR is getting set at the charge termination points, if the voltages relax back into the flat region it will disqualify the Qmax. I haven't had a chance to verify this but it is what I suspect.

Sincerely,

Wyatt Keller

Hello Wyatt,

Could it be because the cell voltage varies too much? When the battery has been relaxed for some time, the minimum cell voltage is less than the flat region voltage, resulting in QMAX not updating. What is the flat region voltage for X0400 and X4100?

Hello Wyatt,

1.“default, this flag is set. The device will take a 48-hour wait before taking an OCV reading if charge stops below the FlatVoltMax” 

The voltage should be greater than the FlatVoltMax. Why does OCVFR set to 1? Charging cutoff OCVFR will be forced to set 1? Check again every 5H, if voltage is greater than FlatVoltMax then OCVFR will be 0, if voltage is less than FlatVoltMax then OCVFR will continue to be 1 until forced to 0 after 48H

2.It looks like I've met the QMAX update criteria.

3. If FAST_QMAX_LRN and FAST_QMAX_FLD are set to 1, will QMAX update be better? What is the impact of batch application?

Hello Jingming,

I'm not sure if we checked all your chem IDs being used, I'm not sure which is being used for this test. Can you clarify what you mean by "X0400 and X4100?"

FAST_QMAX_LRN and FAST_QMAX_FLD will not help, this is only during the learning period were the fast Qmax feature can be used for learning. My understanding is you completed learning and are trying to get further Qmax updates? If you are still trying to complete learning for some cells (even though only one learning cycle is needed) then the fast Qmax could help.

Sincerely,

Wyatt Keller

Hello Wyatt,

1, 400, and 4100 are chemical ids, 400 is learned by GPC, and 4100 is the ID corresponding to the battery model. The ID for the battery data sent earlier is 4100.

2. There was a battery QMAX update yesterday. The ID used by the battery was 400, and it finally succeeded after 10 cycles. Please check the attachment for guidance on how to ensure that QMAX can be updated during mass production.

3. In mass production, only a part of batteries QMAX can be updated, and the updata status of some batteries is always at 06. I would like to know if FAST_QMAX can be enabled to improve this situation so that QMAX can be updated during mass production and customer use.

4.It is found in the attachment that it takes only 20 minutes for OCVFR to go from 1 to 0. After charging, it only takes an hour to relax, and QMAX is updated when the discharge starts.

5.Is OCVFFR=1 after charging? When voltage is detected less than FlatVoltMAX, OCVFR=0. I can't find any pattern in OCVFR, sometimes relax for a long time, the voltage is already very low, OCVFR is still 1

Thanks

QMAX=1 20221222.log

Hello Jingming,

A learning cycle does not need to be completed for every battery pack, and in the field a Qmax doesn't need to happen every cycle.

Due to the holidays I will be delayed to look into your questions further.

Sincerely,

Wyatt Keller

Hello Wyatt,

Could you please reply one by one?

Thanks

Hello Jingming,

I will look at your questions further after the Holidays, either tomorrow or Friday.

Sincerely,

Wyatt Keller

Hello Wyatt,
Have you started work yet? Please reply to each point at work, thank you.
I suspect that the voltage gap between each battery is very large, resulting in the voltage in the "flat voltage region" after the charging cut-off, and then the battery does not QMAX update. But I don't know what is the voltage of the "flat voltage region" of CHEM ID 0400 and 4100?

Hello Wyatt,

1、There are two conditions for QMAX updates:

1).Two OCV read, but [VOK]=0,[REST]=1, the OCV read should be normal, but no update.

2)."If a valid DOD0 (taken at the time previous QMax update) is available, then QMax will also be updated when a valid charge termination is detected,  Where do I know that this is valid DOD0 is available? So I just have to make sure that [VCT] = 1.

2、For QMax update is disqualified, there are two conditions,

1). "If CellVoltage4.. 1 is inside a flat voltage region ", is this voltage at [REST]=1? The battery charge cutoff voltage is always > Q Invalid MaxV. If the voltage is when [REST]=1, it is possible that this causes QMAX not to update.Because the battery voltage consistency is not good, the minimum voltage may be less than Q Invalid MaxV 

2). Where can I read "Offset Error"? I need to confirm whether it exceeds 1% of Design Capacity。

3、[OCVFR] is to detect the Open Circuit Voltage in Flat Region. Why is the Voltage not in Flat Region after the charging cut-off, but [OCVFR]=1. If the minimum voltage at [REST]=1 is greater than Q Invalid MaxV, is [OCVFR] never equal to 0？

Thanks

Hello Wyatt,

According to what you said earlier: "So if the cell voltages become stable and if they are above the flat zone (the margin doesn't apply now) and if temperature is within required limits, the gauge will qualify this for Qmax. " Then [OCVFR] cannot be 0 when [RESE]=1.

But I always measure [OCVFR] to be 0, then [REST] to be 0 again. So I had to leave the battery stable with a minimum voltage greater than Q Invalid MaxV to ensure that QMAX was updated？

Hello Wyatt,

1、There are two conditions for QMAX updates:

1).Two OCV read, but [VOK]=0,[REST]=1, the OCV read should be normal, but no update.

2)."If a valid DOD0 (taken at the time previous QMax update) is available, then QMax will also be updated when a valid charge termination is detected,  Where do I know that this is valid DOD0 is available? So I just have to make sure that [VCT] = 1.

2、For QMax update is disqualified, there are two conditions,

1). "If CellVoltage4.. 1 is inside a flat voltage region ", is this voltage at [REST]=1? The battery charge cutoff voltage is always > Q Invalid MaxV. If the voltage is when [REST]=1, it is possible that this causes QMAX not to update.Because the battery voltage consistency is not good, the minimum voltage may be less than Q Invalid MaxV 

2). Where can I read "Offset Error"? I need to confirm whether it exceeds 1% of Design Capacity。

Thanks

Hello Wyatt,

1、Normally, the charging stop voltage is greater than Q Invalid MaxV. However, after relax, the minimum voltage is less than Q Invalid MaxV. If so, when [REST]=1, the minimum voltage is less than Q Invalid MaxV, so that QMAX is never updated. There's no other way to update it.

2、With the exception of the first point, all of the conditions seen for QMAX to be updated are met. When the charge stops, [VCT] is also 1

Thanks

Hello Wyatt,

If so, then many batteries will never be able to QMAX update, because when [REST]=1, most of the voltage will be below "Q Invalid MaxV". What is the way to update in this case?

Is there a valid DOD0 as long as there is a VCT happening and then the battery is 85% DOD so QMAX can be updated? So you can ignore "If CellVoltage4... 1 is inside a flat voltage region. "? The data includes DOD0_1~4 and QMAX_DOD0_1~4. Which parameter does DOD0 refer to?

Thanks

Hello Wyatt,

1. There are two questions about this:

1). When the charging stop enters relax, the voltage is bove the Q invalid point, but after a long period of relax, when entering [REST] mode, the voltage will be lower than the Q invalid point. Is this Q invalid point a time to relax or a time to rest?

2) Where can we calculate The DOD0 minimum is 37% change between the two OCV points?

2. I have a set of batteries, which have verified 9 cycles through various methods, but none of them has been updated by QMAX. Yesterday, I changed three marks and QMAX was updated. The three marks are: FCSETV and OCVFR should be changed to 0, and SMOOTH should be changed to 1. I have submitted the learning document, please help to check it.

3. Is OCVFR useful only when the charging stop voltage is less than the Q invalid point, it can be forced to OCV after 48 hours, if bove the Q invalid point, OQCVFR useless? In this case, the OCVFR can not be used because the voltage will not fall below he Q invalid point when the charge stops. If OCVFR affects QMAX updates, I think it can be cancelled

OCVFR=0 QMAX no update.csvOCVFR=0 QMAX no update.logOCVFR=1 QMAX update.csvOCVFR=1 QMAX update.log

Hello Wyatt,

1. I mean that when the battery is in relax mode, the voltage is higher than Q invalid point. It takes several hours in relax mode before the battery drops below the Q invalid point. So when [rest] changes to 1, the battery is below Q invalid point. So whether the voltage into the flat region is RELAX or REST.

2. There are many DOD0 values. Which should I watch?

3. I sent two gg files and two log files yesterday. Can you help to check why QMAX is not updated?

Hello Jingming,

The cell must relax for a certain period of time before we set the REST bit which indicates we have been in relax long enough and the criteria for OCV is met. The Cell x DOD0 values, the Qmax values only update when there is a Qmax which is not helpful for analysis.

Sincerely,

Wyatt Keller

Hello Wyatt,

According to the log file I sent before, can you help analyze why QMAX is not updated?

Thanks

Hello Jingming,

I will need until the end of the week to review your data, sorry for the delay.

Sincerely,

Wyatt Keller

Hello Wyatt,

What is the reason why the other file QMAX is not updated? According to our battery characteristics, in order to ensure that QMAX can be updated during mass production, how should we configure? Do you have any suggestions?

Thanks

Hello Wyatt,

[OCVFR] only when "if charging stops within the flat voltage region "will work. According to the log file, the battery will relax long after the charging stops before the voltage below the FlatVoltMax. So the OCVFR doesn't feel very useful. If the voltage below the FlatVoltMax can't be improved after a period of relaxation after charging, then the OCVFR flag can't be helped in any way. I don't know what purpose this OCVFR serves.

For the QMAX update, I see three flags: [FAST_QMAX_FLD], [FAST_QMAX_LRN], [OCVFR], any others? If the battery condition cannot be improved, how should the three flags be set to improve the QMAX update probability during the application?

Having discussed so much, we really can't find a solution. Please kindly make the final answer. I will set it according to your suggestion. Thank you very much