Active cooling system

Faults and Technical chat for the Honda E
SwissChris
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Re: Active cooling system

Post by SwissChris » Tue May 04, 2021 5:01 pm

Warm up yes, cooling no. See also here: http://news.eeworld.com.cn/qrs/ic494986.html, Figure 2.

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Reuben80
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Re: Active cooling system

Post by Reuben80 » Tue May 04, 2021 9:38 pm

SwissChris wrote:
Tue May 04, 2021 5:01 pm
Warm up yes, cooling no. See also here: http://news.eeworld.com.cn/qrs/ic494986.html, Figure 2.
Hmmm, doesn't make sense that if the battery is too hot the system cannot cool it down while on pre ac but it can warm it up.....
I hope it is just not illustrated.

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milligoon
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Re: Active cooling system

Post by milligoon » Tue May 04, 2021 10:04 pm

Why a Chinese document on a Japanese car battery temperature should be taken as gospel? This is just some discussion about the differences in heating between bev and phev. It doesn't state that there is no automated cooling management.

Maybe someone who knows someone who lives somewhere hot can tell us if the coolant system kicks in on a hot day, given UK temperatures at the moment that could be a long time off!
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SwissChris
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Re: Active cooling system

Post by SwissChris » Wed May 05, 2021 6:28 am

Well there is a cooling management implemented in the Honda e, as laid out in the SAE document already posted. However this will only kick in during driving or charging, due to obvious reasons it will not be activated when you remote start your AC. Battery cooling is achieved by using the air flow through the battery radiator in front of the vehicle, supported by the radiator fan. There is no A/C compressor in the battery coolant circuit. If the vehicle is stationary and the battery temperature is outside the ideal frame (25°C - 35°C), it is very likely that the ambient air temperature is pretty high as well and the "wind chill" effect created by the radiator fan will not be sufficient to achieve a substantial cool down of the coolant.

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Reuben80
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Re: Active cooling system

Post by Reuben80 » Wed May 05, 2021 12:31 pm

SwissChris wrote:
Wed May 05, 2021 6:28 am
Well there is a cooling management implemented in the Honda e, as laid out in the SAE document already posted. However this will only kick in during driving or charging, due to obvious reasons it will not be activated when you remote start your AC. Battery cooling is achieved by using the air flow through the battery radiator in front of the vehicle, supported by the radiator fan. There is no A/C compressor in the battery coolant circuit. If the vehicle is stationary and the battery temperature is outside the ideal frame (25°C - 35°C), it is very likely that the ambient air temperature is pretty high as well and the "wind chill" effect created by the radiator fan will not be sufficient to achieve a substantial cool down of the coolant.
Great explanation, thank you. Do you work on similar systems? How come you have this knowledge?

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Reuben80
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Re: Active cooling system

Post by Reuben80 » Wed May 05, 2021 12:33 pm

But why when charging it works? How does it cool the battery if it is stationary?

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milligoon
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Re: Active cooling system

Post by milligoon » Wed May 05, 2021 6:17 pm

Honda needs to release more geeky data on the e in the dash or EV menu as well as in the app
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Number5
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Re: Active cooling system

Post by Number5 » Wed May 05, 2021 8:29 pm

I'm with milligoon, why is this document to be believed. 25- 35 C seems too higher temperature range.
At 35 C my leaf would already be limiting fast charging. In normal use it never approaches 35 C according to leafspy.
Think about the amount of energy required to heat up the 350kg battery, not insignificant.
I think build up of heat dissapates through the battery case in the leaf and to some degree the e.

SwissChris
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Re: Active cooling system

Post by SwissChris » Thu May 06, 2021 8:55 am

Reuben80 wrote:
Wed May 05, 2021 12:31 pm
Great explanation, thank you. Do you work on similar systems? How come you have this knowledge?

I just want to know how things are working, hence I am subscribed to Springer Professional Automotive and other industry related platforms.
Reuben80 wrote:
Wed May 05, 2021 12:33 pm
But why when charging it works? How does it cool the battery if it is stationary?

Well usually your ambient temperatures are well below 35°C, hence there is a cooling effect with the radiator fan activated while charging. Furthermore the energy for the radiator fan and water pump is coming from the charging station, not the EV´s battery.
Number5 wrote:
Wed May 05, 2021 8:29 pm
I'm with milligoon, why is this document to be believed. 25- 35 C seems too higher temperature range.

I just quoted the eeworld doc because it references to two SAE articles written by Honda engineers. Up to you if you believe it or not ;) The 25°C-35°C range is laid out as well in the SAE document. Honda has not published details regarding the battery chemistry of the Panasonic battery in our vehicles, but based on some research I have done on this it is very likely that 192 3.7V 50Ah NCM 622 batteries are used (192x3.7x50 = 35.52 kW/h). It is a known fact that temperatures above 30°C increase battery degradation over time (for NCM 622 as for other LIBs), however the thermal stability of such batteries has improved by using safety electrolytes and by other measures, also reducing the risk of thermal runaways. If you take the battery lifetime into consideration, the time the battery temperature has been stored over 30°C is very limited, thus the impact on battery degradation should be not too big. If you want to further dig in into this very interesting topic, pls. check out this free of charge article: https://link.springer.com/article/10.10 ... 19-00053-3.

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milligoon
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Re: Active cooling system

Post by milligoon » Thu May 06, 2021 9:52 am

Makes you wonder if the Honda was kept from the markets with hotter ambient temperatures because of the temperature restraints? Or are Honda being quite cautious while they gather data?
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