Drive battery degradation . Houston, do we have a problem?

[elm70]

One example of how to abuse a battery of any type: Start with an extremely cold battery pack, don't pre-heat or allow the ICE to run, then drive 20km to work. The poor battery has very high Ri, the chemical reactions are slow, and much of the energy liberated in the cell is converted to heat. Pre-heating or pre-cooling is a battery lifesaver.

Hi AndyH,

I'm struggling to keep up with the technical discussion here, but I'm interested in this comment in the context of the various discussions around how to prevent the ICE from starting up on cold days (not sure if UK cold days qualify as 'cold'). My questions are, if you are able to answer them;

Does the PHEV have battery warming capability, and is this part of why the ICE will sometimes run on startup?
Does an electric 'pre-heat' warm the battery as well as the cabin/windscreen?
How cold does it need to be for battery warming to take place/be required?

Many thanks.

For me 2 points are important :

- Does the lithium m battery suffer any type of damage when used while cold ? (my guess is no ... but happy to be proven wrong)
- What's the point to pre-heat the battery, if battery in cold temperature due to high IR will get automatically warmer ? (unless there is any liquid in the battery which at very low temperature may become solid/crystal , causing some permanent damages like forgetting a beer bottle inside the freezer :mrgreen: )

About our PHEV battery ... as far as I know .. we just have a ventilation system inside the battery compartment ... so no AC with compressor .. no heater in the battery .. as well .. I did not see any air inflow and outflow ... so ... I'm not sure how efficient is our PHEV battery temperature control ....

This battery temperature control ... is also working only when car is charging or active ... in a very hot day, nothing will prevent the battery to get hot inside the PHEV if this is left parked outside under the sun ...

EDIT:
About the ICE kick in ... it has nothing to do with battery ... this is only a design decision from Mitsubishi .. that using electric heater in some condition it will be too slow on heating the cabin, and for this reason, ICE is started for make the cabin warmer in a shorter time.

As far as I know ... AC and Heater for the cabin, are not connected to the battery ventilation ...

 

[anko]

Driving a completely different type car for a while can completely skew your recollection of "how it was".

Please, don't get me started :lol: . But numbers don't lie.

 

[anko]

Speaking of 40kw , or 60kw ... I remember Vtech told us that he can configure / reconfigure the 60kw limit to any other limit ... (he did show on YouTube a 70kw acceleration and he also mention 110kw was possible too)

Did your VTech box mess with this value ? Or did the PHEV firmware decided based on battery condition to change this parameter ?

I think the latter. What Vtech did is rewrite the software of the PHEV ECU. This ECU eventually determines at what power demand the ICE is started. The PHEV Box just reduces the power demanded from the PHEV ECU in an attempt to prevent ICE start.

 

[anko]

Anyhow ... personally .. I would check if the limit of 40kw happen only when battery is discharged or also when SOC is close to 100% .. but it is your car , and I'm already happy you shared this important information with us.

Pretty sure that it is not SOC related (or at least not as much as one would hope). My wife complained the other day the ICE fired up before she had even left our street with a full battery.

 

[AndyH]

We don't drive EVs - we drive hybrids.

I totally disagree. If you were right, why is it called a PHEV and not a PH? All advertisement is about "the average daily commute is less than so many miles, so well within EV range for most people". This is what the Dutch Mitsubishi site says (according to Google Translate):

The innovative Plug-in Hybrid EV system is particularly eco-efficient. For example, you will be carefree with fuel consumption and CO₂ emissions of zero and enjoy the incredible peace during full electric driving. Or opt for hybrid driving when you want to cover longer distances, with low emissions and an impressive fuel efficiency of 1.7 liters / 100 km on average.

Maybe, you are kinda right, as a result of a poor implementation. But that is clearly not how it was supposed to be.

Marketing copywriters can almost say what they want. I prefer to fall back on the technical definitions because it keeps me from pulling my hair out. :lol: A hybrid vehicle has two different ways to turn the wheels. A hybrid electric vehicle uses electricity and 'something else' - usually internal combustion. We even have hydraulic hybrids:http://www.hydraulicspneumatics.com/rail-truck-bus/ups-takes-delivery-hydraulic-hybrid-trucks

https://www.afdc.energy.gov/vehicles/electric_basics_hev.html

We have plug-in hybrids. These are hybrid electric vehicles - using both ICE and electric motors - that also allow us to add energy from a wall plug. For the definitions, the all electric range isn't relevant, until we 'drill down' into the definition tree and subcategorize PHEVs by range: PHEV-20, PHEV-40, etc.

 

[AndyH]

One example of how to abuse a battery of any type: Start with an extremely cold battery pack, don't pre-heat or allow the ICE to run, then drive 20km to work. The poor battery has very high Ri, the chemical reactions are slow, and much of the energy liberated in the cell is converted to heat. Pre-heating or pre-cooling is a battery lifesaver.

Hi AndyH,

I'm struggling to keep up with the technical discussion here, but I'm interested in this comment in the context of the various discussions around how to prevent the ICE from starting up on cold days (not sure if UK cold days qualify as 'cold'). My questions are, if you are able to answer them;

Does the PHEV have battery warming capability, and is this part of why the ICE will sometimes run on startup?
Does an electric 'pre-heat' warm the battery as well as the cabin/windscreen?
How cold does it need to be for battery warming to take place/be required?

Many thanks.

I'm still working through the tech info anko and Trex have posted, as well as the service info. I've found that the battery box has a fan, and an air conditioning heat exchanger used to cool the battery, but don't see anything yet that suggests the battery in our cars is heated.

All I know for sure about heating is that the Volt/Ampera, the smart EV, and Tesla batteries are heated and cooled.

Maybe Trex and/or anko have better details.

ETA... The 'Monroney' sticker for my 2018 North America model includes this text:

Mechanical Features
-12 kW Lithium-ion main drive battery
-120-volt charging cable, switchable 8A/12A
-120V/240V charging system
-DC Fast Charge capability
-Regenerative Braking System (RBS) with steering
mounted paddle shifters
-Main battery warming system
-Charge door light and lid locking system
-Acoustic Vehicle Alert System
-2.0L DOHC MIVEC range extender engine
-60kW Twin AC synchronous electric motors
-Single speed, fixed reduction gear
-Twin Motor Super All-Wheel Control (S-AWC)

I have no idea how it's implemented - whether it's an air warmer or a heating pad in the battery box - or how it's activated.

 

[AndyH]

For me 2 points are important :

- Does the lithium m battery suffer any type of damage when used while cold ? (my guess is no ... but happy to be proven wrong)

Depends on how 'cold' you mean, and the characteristics of the specific lithium chemistry. I know that in general cells should be used 'gently' when very cold until they warm, and I know that cold cells won't deliver full power or energy when cold (we can see that in discharge graphs - look for Trex' recent charts for the LEV50 and compare discharge charts at different temperatures), but I don't yet know the specifics of the cells in our Outlanders beyond those charts.

Here's an overview from a 2011 paper:
http://jes.ecsdl.org/content/158/3/R1.full

Due to the overwhelming number of electrode material and electrolyte solvent/salt combinations used in both commercial batteries and academic studies, it is difficult to develop a coherent and comprehensive picture of all the relevant capacity/power fade mechanisms. However, it is clear that temperature does have an influence on the performance degradation of lithium-ion batteries, and this is true for nearly all positive electrode and electrolyte chemistries.

The exact mechanisms leading to poor performance of lithium-ion batteries at cold temperatures are still not well understood,41 and a review of these mechanisms is outside the scope of this document. Nonetheless, it is clear that the performance of lithium-ion batteries is reduced at lower temperatures for all cell materials. In addition, the charge performance is substantially less than that for discharge. For example, a typical lithium-ion battery can discharge almost 90% of its rated capacity at a C∕5 rate, but cannot accept this same percentage on charging at the same rate and temperature.42 Also, due to significant lithium plating at low temperatures, capacity can be irreversibly lost if charged at low temperatures.42

Table IV shows representative low temperature data for both discharging and charging at cold temperatures. It can be seen that the battery capacity drops with temperature, especially below −20°C . Although the ionic conductivity of the SEI and electrolyte and the diffusion of lithium into the graphite can be reduced significantly at low temperatures, Zhang et al.44 argue that poor performance of lithium-ion batteries at low temperatures is linked to poor charge transfer at the electrode/electrolyte interface. In fact, this poor charge transfer can lead to significant plating on the negative electrode during charging, which can cause irreversible capacity loss from electrolyte reduction. Fan and Tan42 recommended avoiding high charge rates at low temperatures, even at short pulses, to limit capacity fade.

Charging, on the other hand...
https://electronics.stackexchange.c...atteries-in-cold-temperatures-would-harm-them
https://www.sciencedaily.com/releases/2014/09/140903105638.htm

- What's the point to pre-heat the battery, if battery in cold temperature due to high IR will get automatically warmer ? (unless there is any liquid in the battery which at very low temperature may become solid/crystal , causing some permanent damages like forgetting a beer bottle inside the freezer :mrgreen: )

Here's a general look at cell heating in a battery box with a fan:

http://www.catcoinwallets.com/images/posts/EV/Building_Battery_webinar_3-4-09.pdf
Voltage sags deeper in cold cells. Cold cells can release less energy and power. The warmer cells do more of the work, heat faster, and can overheat.

About our PHEV battery ... as far as I know .. we just have a ventilation system inside the battery compartment ... so no AC with compressor .. no heater in the battery .. as well .. I did not see any air inflow and outflow ... so ... I'm not sure how efficient is our PHEV battery temperature control ....

Active battery box cooling from the AC system:
http://www.myoutlanderphev.com/forum/viewtopic.php?f=10&t=1278&start=21
http://mmc-manuals.ru/manuals/outla...ual_2013/2016/54/html/M154940130016302ENG.HTM

 

[elm70]

Active battery box cooling from the AC system:
http://www.myoutlanderphev.com/forum/viewtopic.php?f=10&t=1278&start=21
http://mmc-manuals.ru/manuals/outla...ual_2013/2016/54/html/M154940130016302ENG.HTM

From the link above I don't see any relation between AC and Heating system used for the cabine and "ventilation" inside the battery

The battery for the video, and some diagram on the 2nd link, is looking a box that has only electrical cable connection to the external world.

About cold temperature ... from your link:

Note: I should add that discharging a lithium ion battery in below freezing temperatures is perfectly safe. Most cells have discharge temperature ratings of -20°C or even colder. Only charging a 'frozen' cell need be avoided.

So problem is apparently only charging the battery .. so it sounds that using B5 in cold it should be avoid

 

[elm70]

Speaking of 40kw , or 60kw ... I remember Vtech told us that he can configure / reconfigure the 60kw limit to any other limit ... (he did show on YouTube a 70kw acceleration and he also mention 110kw was possible too)

Did your VTech box mess with this value ? Or did the PHEV firmware decided based on battery condition to change this parameter ?

I think the latter. What Vtech did is rewrite the software of the PHEV ECU. This ECU eventually determines at what power demand the ICE is started. The PHEV Box just reduces the power demanded from the PHEV ECU in an attempt to prevent ICE start.

I don't believe anybody than a team of inhouse developers from Mitsubishi can rewrite the PHEV ECU firmware.

And something is telling me that VTech don't have access to any inhouse Mitsubishi developer.

I bet that VTech just learn how to send configuration/reconfiguration parameter to the PHEV ECU ... and in this way he can change some parameters ... like max power from battery, level of discharge before ICE kick in, etc

Back to VTech box ... it is not only a simple converter for the gas pedal signal intensity ... it has access to the CAN bus, and the Vbox can send instructions/commands over it ...

Unfortunately I was not able to dig into more details, since on my PHEV it was impossible to install the VTech box, else , I was already in discussion with him for have dedicated firmare for the Box in order to activate the 70Kw power from the battery, and eventually other options too.

 

[AndyH]

Active battery box cooling from the AC system:
http://www.myoutlanderphev.com/forum/viewtopic.php?f=10&t=1278&start=21
http://mmc-manuals.ru/manuals/outla...ual_2013/2016/54/html/M154940130016302ENG.HTM

From the link above I don't see any relation between AC and Heating system used for the cabine and "ventilation" inside the battery

Look again, mate. The first link to our tech docs shows the AC loop - "Evaporator (for cooling drive battery)". The service manual note (Pre-removal) talks about the need to evacuate the AC system and disconnect the refrigerant pipes. And here: http://www.myoutlanderphev.com/forum/viewtopic.php?p=13905#p13905 you can see exactly where to 'evaporator' is located inside the battery box.

About cold temperature ... from your link:

Note: I should add that discharging a lithium ion battery in below freezing temperatures is perfectly safe. Most cells have discharge temperature ratings of -20°C or even colder. Only charging a 'frozen' cell need be avoided.

So problem is apparently only charging the battery .. so it sounds that using B5 in cold it should be avoid

Here's the thing: "most" is significant. That means not all of the cells in the lithium family are usable below zero. It makes sense that ours would be - I think the design minimums would require it - but that's an assumption. I have no idea where the 'do not use' is - it could be the -25 warning in the owner's manual that says the EV system won't be allowed to work. What does your owner's manual say?

As for B5...we should be free to select B5 all we want as the computers should keep us from hurting anything. We just won't see much regen until the pack warms, that's all.

It appears that some of our cars have battery warmers as well. This info's from the window sticker for my 2018 NA model:

Mechanical Features
-12 kW Lithium-ion main drive battery
-120-volt charging cable, switchable 8A/12A
-120V/240V charging system
-DC Fast Charge capability
-Regenerative Braking System (RBS) with steering
mounted paddle shifters
-Main battery warming system
-Charge door light and lid locking system
-Acoustic Vehicle Alert System
-2.0L DOHC MIVEC range extender engine
-60kW Twin AC synchronous electric motors
-Single speed, fixed reduction gear
-Twin Motor Super All-Wheel Control (S-AWC)

I have no idea how it's implemented - whether it's an air warmer or a heating pad in the battery box - or how it's activated.

 

[anko]

I don't believe anybody than a team of inhouse developers from Mitsubishi can rewrite the PHEV ECU firmware.

And something is telling me that VTech don't have access to any inhouse Mitsubishi developer.

I bet that VTech just learn how to send configuration/reconfiguration parameter to the PHEV ECU ... and in this way he can change some parameters ... like max power from battery, level of discharge before ICE kick in, etc

Oh come on, that is just a lot of semantics. Hardly the point. And even then, I am quite convinced you underestimate him. For starters, he did use a firmware flasher to achieve what he did. He flashed a PHEV ECU I bought for him in the Netherlands in a junk yard I A habe a spare one on the shelf myself if somebody is interested.

Back to VTech box ... it is not only a simple converter for the gas pedal signal intensity ... it has access to the CAN bus, and the Vbox can send instructions/commands over it ...

What makes you think it does? Or are you just guessing? I am pretty sure it does not. All it needs to know is eco mode on or off. The little circuit board in the box has room for a CANBUS chip, but to my beefy of knowledge it is not installed. And there is no need for one to provide the PHEV box functionality.

 

[anko]

Marketing copywriters can almost say what they want.

Stop right there. You back up your personal opinion by referring to changing advertisements: PHSUV rather than PHEV. But when I bring in two recent examples of Mitsubishi promotional material that clearly refer to the PHEV as being an EV as well, all of a sudden you are no longer interested in marketing? Nice :lol:

 

[AndyH]

Marketing copywriters can almost say what they want.

Stop right there. You back up your personal opinion by referring to changing advertisements: PHSUV rather than PHEV. But when I bring in two recent examples of Mitsubishi promotional material that clearly refer to the PHEV as being an EV as well, all of a sudden you are no longer interested in marketing? Nice :lol:

Wait - what? I didn't back anything up with ad copy - I hope I said that I fall back to the actual definitions. :shock: Yup - that's what I did.

The definitions are codified in a number of places, including in SAE J-1715 - but I don't have a copy of the newest version, so linked to a page posted by the US Dept of Energy that I hope is 'authoritative enough for government work'.
https://www.sae.org/standards/content/j1715_201410/

https://www.afdc.energy.gov/vehicles/electric_basics_hev.html

Hybrid Electric Vehicles

Hybrid electric vehicles (HEVs) are powered by an internal combustion engine or other propulsion source that can run on conventional or alternative fuel in combination with an electric motor that uses energy stored in a battery. HEVs combine the benefits of high fuel economy and low tail pipe emissions with the power and range of conventional vehicles.

https://www.afdc.energy.gov/vehicles/electric.html

Hybrid Electric Vehicles

HEVs are primarily powered by an internal combustion engine that runs on conventional or alternative fuel and an electric motor that uses energy stored in a battery. The battery is charged through regenerative braking and by the internal combustion engine and is not plugged in to charge.

Plug-In Hybrid Electric Vehicles

PHEVs are powered by an internal combustion engine that can run on conventional or alternative fuel and an electric motor that uses energy stored in a battery. The vehicle can be plugged in to an electric power source to charge the battery. Some can travel more than 70 miles on electricity alone, and all can operate solely on gasoline (similar to a conventional hybrid).

All-Electric Vehicles

EVs use a battery to store the electric energy that powers the motor. EV batteries are charged by plugging the vehicle into an electric power source.

For another view, there's always the 2003 classic "Electric Vehicle Technology Explained"
http://ev-bg.com/wordpress1/wp-cont...icle-technology-explained-2003-j-larminie.pdf
Y'all enjoy!

If I've posted anything that you or anyone else wants a source for, yell and I'll do my best to make it happen, or tell you I don't know. I try to cite sources and make sure opinions are noted as such, but I probably mess that up pretty regularly.

 

[anko]

Wait - what? I didn't back anything up with ad copy - I hope I said that I fall back to the actual definitions. :shock: Yup - that's what I did.

I do apologise. That wasn't you who brought that forward. That was Maby Damn small phone screens :evil:

We don't drive EVs - we drive hybrids. Use shore power to pre-heat or pre-cool the battery. Use petrol. The car MUST use petrol - we're going to burn it in regular use, ...

Of course it is not a pure EV, but based on how it is positioned it should be able to behave like one at least on shore range. And why not? It has everything it meeds for that. IMHO, there is no reason why the car MUST use petrol on short ranges. All the definitions in the world don't change that. When the ICE fires up once more 'for no solid reason' it doesn't help me thinking 'ah well, it is not an EV'. Because it can and should behave like on (on short range).

 

[AndyH]

Wait - what? I didn't back anything up with ad copy - I hope I said that I fall back to the actual definitions. :shock: Yup - that's what I did.

I do apologise. That wasn't you who brought that forward. That was Maby Damn small phone screens :evil:

No worries!

We don't drive EVs - we drive hybrids. Use shore power to pre-heat or pre-cool the battery. Use petrol. The car MUST use petrol - we're going to burn it in regular use, ...

Of course it is not a pure EV, but based on how it is positioned it should be able to behave like one at least on shore range. And why not? It has everything it meeds for that. IMHO, there is no reason why the car MUST use petrol on short ranges. All the definitions in the world don't change that. When the ICE fires up once more 'for no solid reason' it doesn't help me thinking 'ah well, it is not an EV'. Because it can and should behave like on (on short range).

Absolutely - we've got the parts we need! And it appears that inside a range of temperatures and/or loads (towing, hills), it does that well!

I guess the difference is the edge cases, and the size of the 'it works' zone is partly defined by the design compromises made. For example - since the car has an ICE, Mitsu engineers didn't have to size the electric cabin heater to keep people toasty warm in the Yukon or the Barents Sea coast. When I drove my car home from Minneapolis in the -7°F/-22°C weather, I didn't have to do 30 minutes of battery pre-heating before departing, and didn't have to stop to recharge about twice as often the way I would have if I tried the journey in my EV. It seems that because of some of the compromises made, there will be times that EV mode simply isn't available to use.

 

[anko]

I guess the difference is the edge cases, and the size of the 'it works' zone is partly defined by the design compromises made. For example - since the car has an ICE, Mitsu engineers didn't have to size the electric cabin heater to keep people toasty warm in the Yukon or the Barents Sea coast. When I drove my car home from Minneapolis in the -7°F/-22°C weather, I didn't have to do 30 minutes of battery pre-heating before departing, and didn't have to stop to recharge about twice as often the way I would have if I tried the journey in my EV. It seems that because of some of the compromises made, there will be times that EV mode simply isn't available to use.

I agree. In some cases, it does make sense to use fuel instead of electricity. Buy, ideally not when the end result is that you arrive at your next charge point with a non-empty battery.

 

[AndyH]

I guess the difference is the edge cases, and the size of the 'it works' zone is partly defined by the design compromises made. For example - since the car has an ICE, Mitsu engineers didn't have to size the electric cabin heater to keep people toasty warm in the Yukon or the Barents Sea coast. When I drove my car home from Minneapolis in the -7°F/-22°C weather, I didn't have to do 30 minutes of battery pre-heating before departing, and didn't have to stop to recharge about twice as often the way I would have if I tried the journey in my EV. It seems that because of some of the compromises made, there will be times that EV mode simply isn't available to use.

I agree. In some cases, it does make sense to use fuel instead of electricity. Buy, ideally not when the end result is that you arrive at your next charge point with a non-empty battery.

As long as it's safe for the life of the battery, then sure! I plan to keep this car until the wheels fall off, so I'm exploring everything for the long term. This thing is different from any EV I've driven, and any other car I've operated.

It dawned on me earlier today that I'm probably 180 degrees out of sync with most here. I've been all electric for the past 6 years and am coming back to something with a tailpipe. (Seriously - I stood in front of a petrol pump and had to think a minute before I remembered all the steps.) I get the impression that the Outlander's EV mode is their first experience with this new way to drive. As with everything else, I may be wrong.

 

[anko]

Surely, you must have heard about the iMiev?

 

[maby]

I guess the difference is the edge cases, and the size of the 'it works' zone is partly defined by the design compromises made. For example - since the car has an ICE, Mitsu engineers didn't have to size the electric cabin heater to keep people toasty warm in the Yukon or the Barents Sea coast. When I drove my car home from Minneapolis in the -7°F/-22°C weather, I didn't have to do 30 minutes of battery pre-heating before departing, and didn't have to stop to recharge about twice as often the way I would have if I tried the journey in my EV. It seems that because of some of the compromises made, there will be times that EV mode simply isn't available to use.

I agree. In some cases, it does make sense to use fuel instead of electricity. Buy, ideally not when the end result is that you arrive at your next charge point with a non-empty battery.

As long as it's safe for the life of the battery, then sure! I plan to keep this car until the wheels fall off, so I'm exploring everything for the long term. This thing is different from any EV I've driven, and any other car I've operated.

It dawned on me earlier today that I'm probably 180 degrees out of sync with most here. I've been all electric for the past 6 years and am coming back to something with a tailpipe. (Seriously - I stood in front of a petrol pump and had to think a minute before I remembered all the steps.) I get the impression that the Outlander's EV mode is their first experience with this new way to drive. As with everything else, I may be wrong.

This has been my approach too - we bought the car as a hybrid - expecting to get a large, semi-offroad Prius. Almost all our usage is outside EV range and I simply drive on "Save" all the time with the battery around 50 to 60% charged. It will be interesting to see how its life expectancy pans out relative to other users here who have gone out of their way to minimise petrol consumption and use the battery as much as possible. Thus far, I'm not aware of any drop in battery capacity - either in terms of EV range or regen braking effort - but my EV range has been just over 20 miles since the day the car left the factory, given my driving style.

 

[Trex]

Almost all our usage is outside EV range and I simply drive on "Save" all the time with the battery around 50 to 60% charged.

OMG

After all those arguments with me and from memory anko on how you just pressed "Save" right from the start when we said you shouldn't for fuel and regen reasons you now write this.

Must be a different maby. :?

Or have I gone to parallel universe.