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> The early ones from ten years ago had no battery management systems I think you misunderstand what a battery management system is. If a Li-Ion battery had no

> The early ones from ten years ago had no battery management systems I think you misunderstand what a battery management system is. If a Li-Ion battery had no BMS -- especially one that is large, high power, and composed of many cells, it would literally be an incendiary bomb if not carefully managed by the user. The BMS is responsible for maintaining the cells -- they must be equalized and cannot go below or above certain voltages, and the charge controller is not the unit responsible for doing this while the pack is in use. By claiming that there were no battery management systems in earlier EVs you are showing ignorance about the workings of these systems to the point where it is difficult to trust the other things you say. What is your background for this knowledge? Can you provide references to your claims?

jillesvangurp 4y ago
The Nissan Leaf had no battery management system when it launched. Many similar cars from that era lacked a BMS. E.g. the Renault Zoe and a few others. I'm not sure about the early Teslas. I think they saw the need for a BMS pretty early. I think you are just playing semantics here. Obviously they had some simplistic controls on the electronics. But no smart distribution of load, cooling systems, etc. Calling people ignorant is not nice BTW. Says more about you than me. Insisting on references is also a bit weak. Where are your references? I suggest you do your homework with some Googling and then come back to apologize. Would be the nice thing to do.
- DoingIsLearning 4y ago
  > Nissan Leaf had no battery management system when it launched. Citation needed? As far as I know even the 2012 Leafs had a per cell thermal management. I think in the earlier Leafs a lot of the intelligence on charging operation and battery cooling/heating was offloaded to the BCM module but it is a bit of a hyperbole to say that there was no battery management. They may not have had a dedicated BMS module in the OEM sense of BMS (like what Infineon now makes) but they certainly had temperature/charge management controls.
  - jnsaff2 4y ago
    There is thermal management and then there is thermal management. Nissan leaf had cell level voltage and temperature monitoring, it also had a rudimentary heating element that would not let the battery freeze solid. Its battery also was poorly designed so some of the cells had worse conditions than others and the batteries "died" because a few cells went out of limits and the BMS would limit the performance/range of the car. The rest of the cells could go much further. Also you should never charge lithium batteries (other than LTO) below freezing as it forms crystals that are lost to the capacity. Leaf did not to my knowledge compensate for this. Moreover 24kWh battery doing 1000 cycles is about 100 000 km of driving. Then there is Tesla batteries that have liquid cooling and heating of the whole pack. Battery is never charged below freezing, also above freezing the charging is adapted to the cell temperatures and for fast charging the battery temp is raised up to 60C, above 65C the cooling kicks in. The batteries are much larger in Teslas, typically say 80kWh. That combined with better efficiency, better battery management, lower power draw per cell, etc means that they get more than 1k useful cycles out of it. Say 2k (tho they claim more, and there is considerable variability due to use and environment). So 500km * 2k cycles is 1 million km. The battery may degrade due to age before it reaches its cycles. Also as mentioned above. Tesla does draw up to 300kW out of the battery. The onboard AC charger is 11kW so if that is bidirectional then the it is really gentle on the battery. That said, I'm not dissing Nissan, they were truly innovative and we owe them lots of gratitude for popularizing EV's and they have also evolved their tech considerably. Others are doing battery management very well as well nowadays.
- Eisenstein 4y ago
  I cannot claim that it is impossible to run a lithium ion battery pack in an EV application without a BMS but I can claim that if you do that it will almost certainly catch on fire. Quote below from (https://batteryuniversity.com/article/bu-908-battery-management-system-bms https://batteryuniversity.com/article/bu-908-battery-managem...): "The purpose of a BMS is to: 1. Provide battery safety and longevity, a must-have for Li-ion. 2. Reveal state-of-function in the form of state-of-charge and state-of-health (capacity) 3. Prompt caution and service. This could be high temperature, cell imbalance or calibration. 4. Indicate end-of-life when the capacity falls below the user-set target threshold. Not all BMS offer all these features. The most basic functions are battery protection and showing state-of-charge (SoC)." Without battery protection and while running many hundreds of individual cells your battery will catch on fire. I will bet the house on that. No EV maker would ever make an EV without a BMS. You have gone beyond ignorance at this point by claiming that you are insulted and asking for an apology. I won't ask you for one, but I will ask for a public correction and acknowledgement that you were wrong.
- Yaggo 4y ago
  You are mixing up battery management system (BMS) with thermal management system. BMS is practically mandatory with multi-cell li-ion systems. Even cheap consumer devices such as laptops have one.
  - jillesvangurp 4y ago
    Can we agree that what modern EVs do for battery management is very different to what early models did and that that has greatly improved battery longevity? I think it's all called battery management. But early EV models did not have a whole lot of it. It obviously had some electronics to read out the current charge and put some basic limits in place. But no thermal management or cooling or any of the smart battery management features you see in more recent models.
    - Eisenstein 4y ago
      You think it is called something, but state it with authority and ask for an apology when corrected. You should work on your communications skills.
- surfpel 4y ago
  > The Nissan Leaf had no battery management system when it launched. You are ignorant of battery systems. It's okay to be ignorant of things but it's not okay to spread misinformation. I am an electrical engineer. I have worked on battery management systems with 100+ million units produced. I can tell you that it would literally be an incendiary bomb without a BMS, and that no part of modern production battery systems are "simplistic", including the Nissan Leafs.

jillesvangurp 4y ago

The Nissan Leaf had no battery management system when it launched. Many similar cars from that era lacked a BMS. E.g. the Renault Zoe and a few others. I'm not sure about the early Teslas. I think they saw the need for a BMS pretty early. I think you are just playing semantics here. Obviously they had some simplistic controls on the electronics. But no smart distribution of load, cooling systems, etc. Calling people ignorant is not nice BTW. Says more about you than me. Insisting on references is also a bit weak. Where are your references? I suggest you do your homework with some Googling and then come back to apologize. Would be the nice thing to do.

DoingIsLearning 4y ago
> Nissan Leaf had no battery management system when it launched. Citation needed? As far as I know even the 2012 Leafs had a per cell thermal management. I think in the earlier Leafs a lot of the intelligence on charging operation and battery cooling/heating was offloaded to the BCM module but it is a bit of a hyperbole to say that there was no battery management. They may not have had a dedicated BMS module in the OEM sense of BMS (like what Infineon now makes) but they certainly had temperature/charge management controls.
- jnsaff2 4y ago
  There is thermal management and then there is thermal management. Nissan leaf had cell level voltage and temperature monitoring, it also had a rudimentary heating element that would not let the battery freeze solid. Its battery also was poorly designed so some of the cells had worse conditions than others and the batteries "died" because a few cells went out of limits and the BMS would limit the performance/range of the car. The rest of the cells could go much further. Also you should never charge lithium batteries (other than LTO) below freezing as it forms crystals that are lost to the capacity. Leaf did not to my knowledge compensate for this. Moreover 24kWh battery doing 1000 cycles is about 100 000 km of driving. Then there is Tesla batteries that have liquid cooling and heating of the whole pack. Battery is never charged below freezing, also above freezing the charging is adapted to the cell temperatures and for fast charging the battery temp is raised up to 60C, above 65C the cooling kicks in. The batteries are much larger in Teslas, typically say 80kWh. That combined with better efficiency, better battery management, lower power draw per cell, etc means that they get more than 1k useful cycles out of it. Say 2k (tho they claim more, and there is considerable variability due to use and environment). So 500km * 2k cycles is 1 million km. The battery may degrade due to age before it reaches its cycles. Also as mentioned above. Tesla does draw up to 300kW out of the battery. The onboard AC charger is 11kW so if that is bidirectional then the it is really gentle on the battery. That said, I'm not dissing Nissan, they were truly innovative and we owe them lots of gratitude for popularizing EV's and they have also evolved their tech considerably. Others are doing battery management very well as well nowadays.
Eisenstein 4y ago
I cannot claim that it is impossible to run a lithium ion battery pack in an EV application without a BMS but I can claim that if you do that it will almost certainly catch on fire. Quote below from (https://batteryuniversity.com/article/bu-908-battery-management-system-bms https://batteryuniversity.com/article/bu-908-battery-managem...): "The purpose of a BMS is to: 1. Provide battery safety and longevity, a must-have for Li-ion. 2. Reveal state-of-function in the form of state-of-charge and state-of-health (capacity) 3. Prompt caution and service. This could be high temperature, cell imbalance or calibration. 4. Indicate end-of-life when the capacity falls below the user-set target threshold. Not all BMS offer all these features. The most basic functions are battery protection and showing state-of-charge (SoC)." Without battery protection and while running many hundreds of individual cells your battery will catch on fire. I will bet the house on that. No EV maker would ever make an EV without a BMS. You have gone beyond ignorance at this point by claiming that you are insulted and asking for an apology. I won't ask you for one, but I will ask for a public correction and acknowledgement that you were wrong.
Yaggo 4y ago
You are mixing up battery management system (BMS) with thermal management system. BMS is practically mandatory with multi-cell li-ion systems. Even cheap consumer devices such as laptops have one.
- jillesvangurp 4y ago
  Can we agree that what modern EVs do for battery management is very different to what early models did and that that has greatly improved battery longevity? I think it's all called battery management. But early EV models did not have a whole lot of it. It obviously had some electronics to read out the current charge and put some basic limits in place. But no thermal management or cooling or any of the smart battery management features you see in more recent models.
  - Eisenstein 4y ago
    You think it is called something, but state it with authority and ask for an apology when corrected. You should work on your communications skills.
surfpel 4y ago
> The Nissan Leaf had no battery management system when it launched. You are ignorant of battery systems. It's okay to be ignorant of things but it's not okay to spread misinformation. I am an electrical engineer. I have worked on battery management systems with 100+ million units produced. I can tell you that it would literally be an incendiary bomb without a BMS, and that no part of modern production battery systems are "simplistic", including the Nissan Leafs.