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  1. J

    Battery open circuit voltage

    Hi, I'm investigating SOC-OCV for Li-ion battery for SOC estimation. I have checked a lot of papers in this matter. I got a bit confused on the U_ocv calculation part. In general, the definition of open circuit voltage is such that the battery is not connected to any load and has reached a...
  2. J

    SOC estimation using coulomb counting

    Hi everyone, I got stuck in the concept of SOC estimation using Coulomb counting and SOC-OCV curve look up table. Actually, one of the main issues which arise for me is when the EV is switch on and then you switched it off. After one minute you are going to switch it on and now EV is under...
  3. J

    Battery SOC/SOH estimation

    I'm working on battery systems and specially on SOC/SOH estimation for EVs. I read a bunch of papers related to SOC/SOH estimation, but I think most of them are not applicable in EVs or at least this time they are not affordable. As far as I understand, coulomb counting or Kalman filter are...
  4. J

    Battery Preheating

    I want to use preheat for battery and when the battery wants to charge subzero it should be triggered. Bu I don't know what's the threshed for disconnecting the circuit. I mean if temperature is lower that 5C the circuit shall be active until the temperature reaches a certain temperature. What's...
  5. J

    Battery mounting

    We have a battery module with the following specification: Height: 300 mm Width: 800 mm Length: 900 mm Weight: 70 kg I would like to test this module in thermal chamber. I want to know can I place the module in any directions? Thermal chamber has 1000 mm length.
  6. J

    Battery nail penetration test

    I'm wondering if it is possible to do nail penetration test for battery modules? I have just seen battery testing in cell level but I'm not sure for module level. Does anybody has any experience about it?
  7. J

    Making a room temperature

    I wan to test my battery module in a constant temperatures (both subzero and high temperature). I don't wan to buy thermal chamber because it is so expensive. I would like to know do you have any suggestions or experience about it? Note: the dimension of the module is following as: Height: 300...
  8. J

    Battery design

    Hi dear friends, I would like to know if we want to design the battery module, do we need to consider energy consumption of components or power demand? For example if we have 3 motors 20 kw, 380Vac, what else parameters do we need to design the battery module/pack?
  9. J

    Maximum short circuit current

    Hi friends, I would like to know how can we calculate the maximum short circuit current? Can we calculated based on maximum discharge rate in datasheet? for example if max. dis. rate is 8C and cell capacity is 20Ah it means our max. short circuit current can be 20*8=160A? Is it right?
  10. J

    Passive cell balancing

    Is the battery cell balancing with passive balancing method done during the charging? I mean, when we plug-in the EV in charge station (electricity), is balancing done at the same time?
  11. J

    Estimated balance minutes

    I was looking for cell balancing time and I saw the following formula from here. But I didn't figure out what's the unit of ocv slope. Is it a factor without unit or degree ...? Estimated balance minutes = (Vcell - Vcell_min ) * Rbal / (Vcell * ocvslope)
  12. J

    Total resistance of the battery pack

    Hi, If we want to calculate the total resistance of the battery module, what components' resistance should we consider? Assume this module is 6S4P. Except the internal resistance of the cells, do we need to consider busbar resistance and other things? If yes, how can we calculate busbar resistance?
  13. J

    Battery preheating circuit

    Hi friends, I googled about battery preheating method for EVs and most of the paper was the different types of preheating methods and I didn't find a suitable and applicable method for EVs. I know these methods are classified by two directions: internal preheating and external preheating. What...
  14. J

    Li-ion battery CAN specification

    Hi, I would like to know if there is any standard for Li-ion battery CAN specification such as type of signals, message error, number of bits allocated for each message, etc.?
  15. J

    Battery pack current (A) Vs. total discharge current (Ah)

    Hi, sorry I'm asking the simple question. but it's confusing issue for me. When we say battery pack current during battery operation (connected to the load), it means discharge current? If we integrated the pack current overtime, it means total discharge current (Ah)? Assume our pack current...
  16. J

    Gross balancing time

    Hi dear friends, I'm trying to calculate the balance current from the following formula: Balance current [A] = Pack size [Ah] / gross balancing time [hours] Ref: http://liionbms.com/php/wp_balance_current.php But I don't know the gross balancing time. Is it in the datasheet? How can I find...
  17. J

    Battery characterization test for modules

    Hi dear friends, So far we had battery characterization test for a single cell. I would like to know how can we test the module (series and parallel multiple cells) using HPPC test? I look forward to hearing your feedback. Best regards, Jonndeka
  18. J

    Voltage difference between modules

    Hi there, I have 10 battery modules in a pack. Each module has 51 volts. I would like to know how much voltage difference are allowed between to modules? I mean more than how much voltage the BMS needs voltage balancing between these modules? Best regards, Reza
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