BQ40Z50-R1: change Trem V

hi Star,

目前使用方式有按造2.3.5要求進行

電池容量4040mAh 改設定Design Capacity mAh = 2880, Design Capacity cWh = 1036cWh

(以上設定為預估客戶的使用容量變成4.2V ~ 3.45V )

充電4.2V/1A/cut off 120mA

放電使用0.28C (0.808A) to 3450mV

仍無法更新Qmax / FCC / 另RSOC 在充放電中3.7V以上才開始進行計算以下為本次的log data2022-12-28_3450.xlsx

hi Star,

目前研究發現RemCap 不更新,應該是這個影響FCC等計算錯誤

請問有何原因會導致無法更新RC

您好，design capacity建议根据电芯规格书填写

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您好

Setting TermV to high voltages like 3400 mV can cause gauging issues since voltage might fall in the flat zone and it is hard for the gauge to predict. Also, if TermV is set to 3400 mV and a big load is present, the loaded cell voltage could fall near EDV even with a charged cell of 3700 mV. At this point SOC will drop to 0%.

For this it is recommended to increase Reserve Capacity and lower/keep TermV near 3000mV. This is a trial error test, and customer will need to do it several times until gauge is best tuned.

I suggest following section 3 from the below app note. SLUA948

https://www.ti.com/lit/an/slua948/slua948.pdf?ts=1672327212389&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FBQ27426%253Futm_source%253Dgoogle%2526utm_medium%253Dcpc%2526utm_campaign%253Dapp-null-null-GPN_EN-cpc-pf-google-wwe%2526utm_content%253DBQ27426%2526ds_k%253DBQ27426%2526DCM%253Dyes%2526%2526utm_source%253Dgoogle%2526utm_medium%253Dcpc%2526utm_campaign%253D%2526utm_content%253D%2526ds_k%253Dbq27426%2526DCM%253Dyes%2526gclid%253DCjwKCAiAkrWdBhBkEiwAZ9cdcOudzbU-KFBkP8w5-wbuQRoGfs47MMaM2Xxq0dmVIOSkPWtUyykPmBoCnGsQAvD_BwE%2526gclsrc%253Daw.ds

hi Star,

1. 2023-01-03 modify design cap 3950mAh to 2880mAh / Term V 3000mV to 3450mV / Reserve Cap-mAh 1550mAh

2. 2023-01-04 modify design cap 3950mAh to 2880mAh / Term V 3000mV to 3450mV

在1狀況下 充電RSOC /RC很久時間以後才會開始計數 + QMAX 不更新，

在2狀況下 充電RSOC /RC會正常計數 BUT QMAX 不更新，

請問是否用2的狀況使用是沒有問題的

APP00379 DF10.rar

您好，建议您多试几次，并且做一下充放电看一下会不会出现RSOC跳变的情况。调整到最合适的参数。

hi Star,

應該說目前多顆測試是正常的的RSOC跳動，FCC/RM/RA table 等都有更新且符合之前正常充放的曲線，但唯獨Qmax 沒有更新這點我不能確認是否GG後續計算是否正常

另案多種測試條件下，使用Reserve Cap-mAh這個方式是不太能正常計算RSOC/FCC/RM ( 這邊均在3.7V以上才會開始計算跳動)

只能將原額定容量(Design capacity)下修的方式去進行learning才可以正確地計算RSOC

您好，

There is a misunderstanding, please let me be more clear.

• Design Capacity should not be changed, it should always stay at the stated nominal capacity of the cell manufacturer datasheet.
• Reserve Cap - mAh should not be increased that much. In the app note example this was increased by few hundreds. For instance, start with 450 mAh. What this would do is report SOC = 0% when cell voltage is near 3400 mV. Simulations will still run with the Reserve capacity after SOC = 0%
  
  
• Please keep TermV at 3000 mV 
  
  
• Design voltage should be set to the highest charged voltage of the cell. 
  
  
• Qmax Cell0 should be left at the same last reported value when customer had the initial configuration. Please see below：
  Again, these are trial errors, but I am sure that more accurate results will be obtained if Design Capacity is not touched and if increase Reserve Cap by few hundreds.

hi Star,

同我所述與測試結果，單純調整 Reserve Cap-mAh ( 本次使用395mAh) 使得電池在放電約3.2V 計算RSOC = 0%

但影響充電須至3.5V以上才開始計算RM or RSOC

BR

Luke

您好，建议多次调整Reserve cap达到最合适的结果。

hi Star,

能否有其他的建議，因為這個循環已做了快20cycle了

一直在充電的時候有我說的上述問題( 充電時 RM 延遲計算)

另外Reserve cap 調整也同我的估計一樣僅能到3.2V時候計算到0% ( log data 2023-01-09_TI SET.rar)

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