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Kia Soul EV 2020
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Discussion Starter #1
Overheating the EV battery while parked in hot sunshine for a long time will degrade a battery. And with the car switched off there is no battery management system running to keep it cool.

Buy a white car
Park in shade.
But if your only parking space is in full sunshine then it is easy to make made to measure sun blinds for each window that will help keep your car's interior cool, and for little cost.

 

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Presumably more or less all EVs have a sensor that reads battery temperature directly or indirectly. I’m sure some of the bright sparks on the forum could figure out how to access the daytime max temperature.
In April in the UK. I can’t say I’m worried enough to bother looking personally.
 

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Overheating the EV battery while parked in hot sunshine for a long time will degrade a battery. And with the car switched off there is no battery management system running to keep it cool.

Buy a white car
Park in shade.
But if your only parking space is in full sunshine then it is easy to make made to measure sun blinds for each window that will help keep your car's interior cool, and for little cost.

Forum members here can be a bit abrasive; I'll double up on that. As COVID-19 is keeping me busy with studying philosophy, I need a definition of these terms:

  • what does 'hot sunshine' mean
  • what does 'long time' mean
  • what does 'degrade' mean
Most batteries are unable to reach 50C when the car is in direct sunlight. At 50-55C, the Manganese or Iron in most batteries (I think also a Soul is using batteries with iron contents) will start changing their structure and will lose integrity of the chemical structure, indeed will lose some of their conductive properties.

But to reach 50+C you have to put the cell/pouch itself in direct sunlight, same temperature outside and in direct exposure as when the train rails begin to bend in summer; the rails are under direct sun exposure for long periods of time.

Since the battery pack is underneath the car it will most likely stay at ambient, shade temperature, even if the car is in direct sunlight, so let's say a maximum of 40C. Please note also that most of the vehicles and their components are tested in extreme heat and extreme cold conditions.
 

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Kia Soul EV 2020
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Discussion Starter #11
A good paper to read to understand the relationship between temperature and degradation of Lithium based batteries is:
Europe PMC

Their conclusions include the following "From our analysis, we can see that increasing the operating temperature increases the degradation rates of all components in the LiB which include maximum charge storage capacity, the effectiveness of the LCO electrode in storing Li-ions, charge transfer rate constant, effectiveness of the graphite electrode in providing its stored Li-ions, total resistance of electrode resistance and electrode/electrolyte resistance, Warburg element resistance, Warburg element capacitance and Warburg RC time constant. The increase in the degradation rates of the Warburg element and cell impedance are particularly sensitive to the operating temperature. We also showed that the increase in the degradation rate of irreversible capacity loss of LiB (i.e. SoH) with temperature is due mainly to the formation and modification of the surface films on the electrode and to the structural/phase changes of the LCO electrode."

Their graphs show a noticeable effect above 25C, but other reviewers comment that significant effects are above 35C.

An article here: How Long Does It Take a Parked Car to Reach Deadly Hot Temperatures? reports tests on how quickly car interiors heat up and what temperatures can be reached.

High temperatures inside a car can have an impact on the electronics and display screens on the dash - which often heats the fastest, and can also degrade smart phones, cameras and laptops left inside a hot car.
Effect Of Temperature And Humidity On Electronic Components

Even under normal weather in the UK I have found temperatures in ICE cars cause enough outgassing of volatile components that condense on the windscreen and create a slightly opaque film.
Much more noticeable in hotter climates.
What's that fog? It could be your dashboard cooking
 

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A good paper to read to understand the relationship between temperature and degradation of Lithium based batteries is:
Europe PMC

Their conclusions include the following "From our analysis, we can see that increasing the operating temperature increases the degradation rates of all components in the LiB which include maximum charge storage capacity, the effectiveness of the LCO electrode in storing Li-ions, charge transfer rate constant, effectiveness of the graphite electrode in providing its stored Li-ions, total resistance of electrode resistance and electrode/electrolyte resistance, Warburg element resistance, Warburg element capacitance and Warburg RC time constant. The increase in the degradation rates of the Warburg element and cell impedance are particularly sensitive to the operating temperature. We also showed that the increase in the degradation rate of irreversible capacity loss of LiB (i.e. SoH) with temperature is due mainly to the formation and modification of the surface films on the electrode and to the structural/phase changes of the LCO electrode."

Their graphs show a noticeable effect above 25C, but other reviewers comment that significant effects are above 35C.

An article here: How Long Does It Take a Parked Car to Reach Deadly Hot Temperatures? reports tests on how quickly car interiors heat up and what temperatures can be reached.

High temperatures inside a car can have an impact on the electronics and display screens on the dash - which often heats the fastest, and can also degrade smart phones, cameras and laptops left inside a hot car.
Effect Of Temperature And Humidity On Electronic Components

Even under normal weather in the UK I have found temperatures in ICE cars cause enough outgassing of volatile components that condense on the windscreen and create a slightly opaque film.
Much more noticeable in hotter climates.
What's that fog? It could be your dashboard cooking
I’m sorry, this is disingenuous for two reasons:
  1. Cabin temperature is not the same as battery temperature. It’s highly unlikely you could get the battery core much above 25 degrees in the UK.
  2. Damage wouldn’t occur if the pack isn’t being used. As soon as you turn the car on, the cooling system would kick in if the pack was too hot.
So we we really need more stupid myths to put people off EVs?

I’m waiting for the first comment ‘well I won’t get an EV because you can’t leave them out in the sun’.
 

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So my car has a dog mode, can crack the windows open via the app and can be set to maintain a low inside temp which will cut off at 20%. However the large screen gets almost too hot to touch in direct sunlight when parked and that can cause screen issues so one of the many screen shades available helps a lot there.

Now if someone could please start to make half covers like the environment cover available from BMW for the i3 then I'd have one. Great little cover that almost fitted (worked in all weathers on the i3) to my current car but was a bit too loose.
 

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So my car has a dog mode, can crack the windows open via the app and can be set to maintain a low inside temp which will cut off at 20%.
Please don’t ever rely on that to keep your pet ‘safe’. I’m not saying you do, and it’s in the context of a different issue, but we don’t want to perpetuate the idea that this is ever ok.

It’s alright until the tech fails or your battery gets to 20%.

The police are regularly called on to extract distressed dogs and often children from unattended hot cars.

My mates a vet, he tells me that trying to help a dog in the late stages of heat stroke is particularly distressing.
 

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Please don’t ever rely on that to keep your pet ‘safe’. I’m not saying you do, and it’s in the context of a different issue, but we don’t want to perpetuate the idea that this is ever ok.

It’s alright until the tech fails or your battery gets to 20%.

The police are regularly called on to extract distressed dogs and often children from unattended hot cars.

My mates a vet, he tells me that trying to help a dog in the late stages of heat stroke is particularly distressing.
No good point and I blame the lazy yanks again!

I don't have any pets but would never leave them unattended anyway. Main reason I've never had a dog though is because I regularly hear neighbours dogs whining during the day having been left alone. I could never do that to one.
 
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