BMW 3: Cooling system
To increase the service life of the high-voltage battery unit and obtain the greatest possible power, it is operated in a defined temperature range. The high-voltage battery unit is essentially operational at an ambient temperature of -40 ºF to 131 ºF (-40 ºC to +55 ºC ) (actual cell temperature). In terms of temperature behavior the high-voltage battery unit is a slow-action system, i.e. it takes several hours until the cells assume the ambient temperature. Therefore having the battery spend a short period of time in an extremely hot or cold environment does not mean that the cells will already have assumed this temperature.
However, the optimal range of the temperature with regard to service life and performance is more limited. It is between +77 ºF and +104 ºF (+25 ºC and +40 ºC). Here, we are referring to the cell temperature, and not the outside temperature. If the cell temperature is continuously significantly above this range with simultaneously high performance, this has a negative effect on the service life of the battery cells. To counteract this effect, as well as ensure maximum performance at all outside temperatures, the high-voltage battery unit of the G20 PHEV has a regulated cooling system.
If the temperature of the battery cells is significantly below the optimal operating temperature of +77 ºF (+25 ºC), their performance would be temporarily restricted and the efficiency of the energy conversion would not be optimal. This is an unavoidable chemical effect of lithium-ion batteries.
If a vehicle is parked for an extended period (e.g. a few days) at a very low ambient temperature, the battery cells also take on this low ambient temperature. In this situation it is possible the full electrical driving power is not available at the start of the journey.
In this case the combustion engine assumes the drive of the vehicle. Pure electric driving (ELECTRIC driving mode) is no longer possible or cannot be activated.
This is also displayed to the customer as a CC message: "Electric driving temporarily restricted. You can continue to drive. Full electrical drive power will be available again after the high-voltage battery has warmed up/cooled down".
Heating to warm up the battery cells is not available for the SP41 High-voltage battery.
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Overview
G20 PHEV, system overview of climate control - Installation locations
Combined expansion and shutoff valve at the evaporator
Combined expansion and shutoff valve at the high-voltage battery u
Functions
The cooling system has 2 operating conditions, which result from its
function:
Cooling OFF
Cooling ON
Cooling OFF operating condition
The "Cooling OFF" operating condition is active when the cell
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Labels
Three signs are attached to the housing of the high-voltage battery unit: 1
type plate and 2 warning
stickers. The type plate provides logistical information (e.g. part number) and
the key technical data
(e.g. nominal voltage). The warning stickers point to the lithium-ion technology
on the one h
System limits
Certain noises can be detected and may lead
to problems. Keep the doors, windows, and
glass sunroof closed.
Noises from the front passenger or the rear
seat bench can impair the system. Avoid
making other noise in the vehicle while
speaking.
Major language dialects can cause problems
with
