Is Non-Passive Cooling bad for Lithium Ion Cells?











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I'm in the process of designing a device capable of charging, discharging and testing internal resistance of 18650 cells. My device will be capable of testing 100x 18650 at the same time, each will have their dedicated module which allows them to run independent from one another.



The pre-designed modules are capable of charging and discharging at 1A however they also have a feature which throttles and reduces the wattage when the battery becomes too hot. This feature is important as this will help answer my question at the end.



In the charging phase of the test they are only charged at around 250ma as this helps to find cells with internal problems and cause the cell to run hot, so no throttling will occur.



During the discharge phase however I need to test the cells at 1A discharge but often the modules will throttle because the battery is getting warm/hot.



I've read comments, forums and even articles saying you should not cool lithium batteries since they cook inside or they change the chemistry within the battery, but I'm unable to find any reputable information that could be considered fact, I know that many electric cars have air ducts to help cool the battery but this doesn't mean its good for the batteries? I'm really unsure and confused.



Is there any scientific reason why you should NOT blow air across batteries while in use or during a charge cycle?










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    up vote
    4
    down vote

    favorite












    I'm in the process of designing a device capable of charging, discharging and testing internal resistance of 18650 cells. My device will be capable of testing 100x 18650 at the same time, each will have their dedicated module which allows them to run independent from one another.



    The pre-designed modules are capable of charging and discharging at 1A however they also have a feature which throttles and reduces the wattage when the battery becomes too hot. This feature is important as this will help answer my question at the end.



    In the charging phase of the test they are only charged at around 250ma as this helps to find cells with internal problems and cause the cell to run hot, so no throttling will occur.



    During the discharge phase however I need to test the cells at 1A discharge but often the modules will throttle because the battery is getting warm/hot.



    I've read comments, forums and even articles saying you should not cool lithium batteries since they cook inside or they change the chemistry within the battery, but I'm unable to find any reputable information that could be considered fact, I know that many electric cars have air ducts to help cool the battery but this doesn't mean its good for the batteries? I'm really unsure and confused.



    Is there any scientific reason why you should NOT blow air across batteries while in use or during a charge cycle?










    share|improve this question
























      up vote
      4
      down vote

      favorite









      up vote
      4
      down vote

      favorite











      I'm in the process of designing a device capable of charging, discharging and testing internal resistance of 18650 cells. My device will be capable of testing 100x 18650 at the same time, each will have their dedicated module which allows them to run independent from one another.



      The pre-designed modules are capable of charging and discharging at 1A however they also have a feature which throttles and reduces the wattage when the battery becomes too hot. This feature is important as this will help answer my question at the end.



      In the charging phase of the test they are only charged at around 250ma as this helps to find cells with internal problems and cause the cell to run hot, so no throttling will occur.



      During the discharge phase however I need to test the cells at 1A discharge but often the modules will throttle because the battery is getting warm/hot.



      I've read comments, forums and even articles saying you should not cool lithium batteries since they cook inside or they change the chemistry within the battery, but I'm unable to find any reputable information that could be considered fact, I know that many electric cars have air ducts to help cool the battery but this doesn't mean its good for the batteries? I'm really unsure and confused.



      Is there any scientific reason why you should NOT blow air across batteries while in use or during a charge cycle?










      share|improve this question













      I'm in the process of designing a device capable of charging, discharging and testing internal resistance of 18650 cells. My device will be capable of testing 100x 18650 at the same time, each will have their dedicated module which allows them to run independent from one another.



      The pre-designed modules are capable of charging and discharging at 1A however they also have a feature which throttles and reduces the wattage when the battery becomes too hot. This feature is important as this will help answer my question at the end.



      In the charging phase of the test they are only charged at around 250ma as this helps to find cells with internal problems and cause the cell to run hot, so no throttling will occur.



      During the discharge phase however I need to test the cells at 1A discharge but often the modules will throttle because the battery is getting warm/hot.



      I've read comments, forums and even articles saying you should not cool lithium batteries since they cook inside or they change the chemistry within the battery, but I'm unable to find any reputable information that could be considered fact, I know that many electric cars have air ducts to help cool the battery but this doesn't mean its good for the batteries? I'm really unsure and confused.



      Is there any scientific reason why you should NOT blow air across batteries while in use or during a charge cycle?







      battery-charging lithium-ion discharge cooling battery-chemistry






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      asked Nov 7 at 18:36









      Simon Hayter

      182210




      182210






















          2 Answers
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          5
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          Your concern is somewhat misplaced. At 1 A charge-discharge, normal 18650 Li-Ion batteries do not heat up. Consider that normal battery heats up only due to Joule dissipation over ESR, and the ESR of most 18650 cell is under 100-150 mOhms. So the maximum internal dissipation is under 200 mW, which, for the physical size (and surface area) of 18650 cell is nearly nothing.



          However, since you plan to discharge them, you will have full 4 W dissipation in each of your loads, so a fan blower will be a must.



          Car batteries gets discharged (and charged during recuperative braking) at much-much higher rates, and only then the internal dissipation/heat generation becomes an issue.






          share|improve this answer























          • Most of the batteries I have are Samsung 25R's which are notorious for being a high drain and fast charge battery, they ain't hot but they certainly are warm after 2 hours of draining, maybe the problem is the modules are running hot rather than the batteries, but is it okay to blow air on one side of a lithium?
            – Simon Hayter
            Nov 7 at 19:14










          • @SimonHayter, are you sure that the heat is coming from batteries, and not spreading up from your drain load? In any case you will need a blower during discharge stage, and it will do no harm if it will continue to blow during charge stage.
            – Ale..chenski
            Nov 7 at 19:19


















          up vote
          4
          down vote













          Tesla 18650 batteries are cooled by propylene glycol coolant in a heat exchanger system.



          See, for example, US20140178722A1 and US 8,758,924



          Some more information on Tesla's particular implementation here.






          share|improve this answer





















          • Yea the heat is evenly spread, my idea was to have a fan blowing on them but my concern was people saying fans are bad for Lithium because they alter the chemistry as heat is not even spread causing hot spots.
            – Simon Hayter
            Nov 7 at 19:16










          • If it's not a problem with Tesla's design I can't imagine a fan is going to cause issues.
            – Spehro Pefhany
            Nov 7 at 19:19











          Your Answer





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          2 Answers
          2






          active

          oldest

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          2 Answers
          2






          active

          oldest

          votes









          active

          oldest

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          active

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          up vote
          5
          down vote













          Your concern is somewhat misplaced. At 1 A charge-discharge, normal 18650 Li-Ion batteries do not heat up. Consider that normal battery heats up only due to Joule dissipation over ESR, and the ESR of most 18650 cell is under 100-150 mOhms. So the maximum internal dissipation is under 200 mW, which, for the physical size (and surface area) of 18650 cell is nearly nothing.



          However, since you plan to discharge them, you will have full 4 W dissipation in each of your loads, so a fan blower will be a must.



          Car batteries gets discharged (and charged during recuperative braking) at much-much higher rates, and only then the internal dissipation/heat generation becomes an issue.






          share|improve this answer























          • Most of the batteries I have are Samsung 25R's which are notorious for being a high drain and fast charge battery, they ain't hot but they certainly are warm after 2 hours of draining, maybe the problem is the modules are running hot rather than the batteries, but is it okay to blow air on one side of a lithium?
            – Simon Hayter
            Nov 7 at 19:14










          • @SimonHayter, are you sure that the heat is coming from batteries, and not spreading up from your drain load? In any case you will need a blower during discharge stage, and it will do no harm if it will continue to blow during charge stage.
            – Ale..chenski
            Nov 7 at 19:19















          up vote
          5
          down vote













          Your concern is somewhat misplaced. At 1 A charge-discharge, normal 18650 Li-Ion batteries do not heat up. Consider that normal battery heats up only due to Joule dissipation over ESR, and the ESR of most 18650 cell is under 100-150 mOhms. So the maximum internal dissipation is under 200 mW, which, for the physical size (and surface area) of 18650 cell is nearly nothing.



          However, since you plan to discharge them, you will have full 4 W dissipation in each of your loads, so a fan blower will be a must.



          Car batteries gets discharged (and charged during recuperative braking) at much-much higher rates, and only then the internal dissipation/heat generation becomes an issue.






          share|improve this answer























          • Most of the batteries I have are Samsung 25R's which are notorious for being a high drain and fast charge battery, they ain't hot but they certainly are warm after 2 hours of draining, maybe the problem is the modules are running hot rather than the batteries, but is it okay to blow air on one side of a lithium?
            – Simon Hayter
            Nov 7 at 19:14










          • @SimonHayter, are you sure that the heat is coming from batteries, and not spreading up from your drain load? In any case you will need a blower during discharge stage, and it will do no harm if it will continue to blow during charge stage.
            – Ale..chenski
            Nov 7 at 19:19













          up vote
          5
          down vote










          up vote
          5
          down vote









          Your concern is somewhat misplaced. At 1 A charge-discharge, normal 18650 Li-Ion batteries do not heat up. Consider that normal battery heats up only due to Joule dissipation over ESR, and the ESR of most 18650 cell is under 100-150 mOhms. So the maximum internal dissipation is under 200 mW, which, for the physical size (and surface area) of 18650 cell is nearly nothing.



          However, since you plan to discharge them, you will have full 4 W dissipation in each of your loads, so a fan blower will be a must.



          Car batteries gets discharged (and charged during recuperative braking) at much-much higher rates, and only then the internal dissipation/heat generation becomes an issue.






          share|improve this answer














          Your concern is somewhat misplaced. At 1 A charge-discharge, normal 18650 Li-Ion batteries do not heat up. Consider that normal battery heats up only due to Joule dissipation over ESR, and the ESR of most 18650 cell is under 100-150 mOhms. So the maximum internal dissipation is under 200 mW, which, for the physical size (and surface area) of 18650 cell is nearly nothing.



          However, since you plan to discharge them, you will have full 4 W dissipation in each of your loads, so a fan blower will be a must.



          Car batteries gets discharged (and charged during recuperative braking) at much-much higher rates, and only then the internal dissipation/heat generation becomes an issue.







          share|improve this answer














          share|improve this answer



          share|improve this answer








          edited Nov 7 at 19:08

























          answered Nov 7 at 18:56









          Ale..chenski

          25.7k11860




          25.7k11860












          • Most of the batteries I have are Samsung 25R's which are notorious for being a high drain and fast charge battery, they ain't hot but they certainly are warm after 2 hours of draining, maybe the problem is the modules are running hot rather than the batteries, but is it okay to blow air on one side of a lithium?
            – Simon Hayter
            Nov 7 at 19:14










          • @SimonHayter, are you sure that the heat is coming from batteries, and not spreading up from your drain load? In any case you will need a blower during discharge stage, and it will do no harm if it will continue to blow during charge stage.
            – Ale..chenski
            Nov 7 at 19:19


















          • Most of the batteries I have are Samsung 25R's which are notorious for being a high drain and fast charge battery, they ain't hot but they certainly are warm after 2 hours of draining, maybe the problem is the modules are running hot rather than the batteries, but is it okay to blow air on one side of a lithium?
            – Simon Hayter
            Nov 7 at 19:14










          • @SimonHayter, are you sure that the heat is coming from batteries, and not spreading up from your drain load? In any case you will need a blower during discharge stage, and it will do no harm if it will continue to blow during charge stage.
            – Ale..chenski
            Nov 7 at 19:19
















          Most of the batteries I have are Samsung 25R's which are notorious for being a high drain and fast charge battery, they ain't hot but they certainly are warm after 2 hours of draining, maybe the problem is the modules are running hot rather than the batteries, but is it okay to blow air on one side of a lithium?
          – Simon Hayter
          Nov 7 at 19:14




          Most of the batteries I have are Samsung 25R's which are notorious for being a high drain and fast charge battery, they ain't hot but they certainly are warm after 2 hours of draining, maybe the problem is the modules are running hot rather than the batteries, but is it okay to blow air on one side of a lithium?
          – Simon Hayter
          Nov 7 at 19:14












          @SimonHayter, are you sure that the heat is coming from batteries, and not spreading up from your drain load? In any case you will need a blower during discharge stage, and it will do no harm if it will continue to blow during charge stage.
          – Ale..chenski
          Nov 7 at 19:19




          @SimonHayter, are you sure that the heat is coming from batteries, and not spreading up from your drain load? In any case you will need a blower during discharge stage, and it will do no harm if it will continue to blow during charge stage.
          – Ale..chenski
          Nov 7 at 19:19












          up vote
          4
          down vote













          Tesla 18650 batteries are cooled by propylene glycol coolant in a heat exchanger system.



          See, for example, US20140178722A1 and US 8,758,924



          Some more information on Tesla's particular implementation here.






          share|improve this answer





















          • Yea the heat is evenly spread, my idea was to have a fan blowing on them but my concern was people saying fans are bad for Lithium because they alter the chemistry as heat is not even spread causing hot spots.
            – Simon Hayter
            Nov 7 at 19:16










          • If it's not a problem with Tesla's design I can't imagine a fan is going to cause issues.
            – Spehro Pefhany
            Nov 7 at 19:19















          up vote
          4
          down vote













          Tesla 18650 batteries are cooled by propylene glycol coolant in a heat exchanger system.



          See, for example, US20140178722A1 and US 8,758,924



          Some more information on Tesla's particular implementation here.






          share|improve this answer





















          • Yea the heat is evenly spread, my idea was to have a fan blowing on them but my concern was people saying fans are bad for Lithium because they alter the chemistry as heat is not even spread causing hot spots.
            – Simon Hayter
            Nov 7 at 19:16










          • If it's not a problem with Tesla's design I can't imagine a fan is going to cause issues.
            – Spehro Pefhany
            Nov 7 at 19:19













          up vote
          4
          down vote










          up vote
          4
          down vote









          Tesla 18650 batteries are cooled by propylene glycol coolant in a heat exchanger system.



          See, for example, US20140178722A1 and US 8,758,924



          Some more information on Tesla's particular implementation here.






          share|improve this answer












          Tesla 18650 batteries are cooled by propylene glycol coolant in a heat exchanger system.



          See, for example, US20140178722A1 and US 8,758,924



          Some more information on Tesla's particular implementation here.







          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered Nov 7 at 18:50









          Spehro Pefhany

          200k4146399




          200k4146399












          • Yea the heat is evenly spread, my idea was to have a fan blowing on them but my concern was people saying fans are bad for Lithium because they alter the chemistry as heat is not even spread causing hot spots.
            – Simon Hayter
            Nov 7 at 19:16










          • If it's not a problem with Tesla's design I can't imagine a fan is going to cause issues.
            – Spehro Pefhany
            Nov 7 at 19:19


















          • Yea the heat is evenly spread, my idea was to have a fan blowing on them but my concern was people saying fans are bad for Lithium because they alter the chemistry as heat is not even spread causing hot spots.
            – Simon Hayter
            Nov 7 at 19:16










          • If it's not a problem with Tesla's design I can't imagine a fan is going to cause issues.
            – Spehro Pefhany
            Nov 7 at 19:19
















          Yea the heat is evenly spread, my idea was to have a fan blowing on them but my concern was people saying fans are bad for Lithium because they alter the chemistry as heat is not even spread causing hot spots.
          – Simon Hayter
          Nov 7 at 19:16




          Yea the heat is evenly spread, my idea was to have a fan blowing on them but my concern was people saying fans are bad for Lithium because they alter the chemistry as heat is not even spread causing hot spots.
          – Simon Hayter
          Nov 7 at 19:16












          If it's not a problem with Tesla's design I can't imagine a fan is going to cause issues.
          – Spehro Pefhany
          Nov 7 at 19:19




          If it's not a problem with Tesla's design I can't imagine a fan is going to cause issues.
          – Spehro Pefhany
          Nov 7 at 19:19


















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