BMW I01 Product Information page 133

I01￿High-voltage￿Components
6.￿Charging￿the￿High-voltage￿Battery
For￿DC￿charging￿the￿LIM￿closes￿the￿two￿switch￿contactors￿in￿the￿KLE,￿thus￿enabling￿the￿shift￿through
from￿the￿direct￿current￿voltage￿from￿the￿DC￿charging￿station￿to￿the￿high-voltage￿battery.￿The￿LIM￿tests
after￿every￿completed￿DC￿charging￿procedure￿the￿DC￿switch￿contactors￿so￿that￿a￿switch￿contactor
label￿(switch￿contactor￿cannot￿open￿the￿contacts)￿is￿identified.￿A￿switch￿contactor￿label￿(single￿or
double)￿is￿identified￿by￿the￿LIM￿and￿sent￿to￿the￿EME￿as￿a￿fault￿code.￿If￿during￿the￿charging￿procedure
no￿valid￿pilot￿signal￿is￿identified￿by￿the￿LIM,￿the￿LIM￿must￿open￿the￿DC￿switch￿contactors￿within
200 ms.
The￿direct￿current￿voltage￿applied￿at￿the￿charging￿socket￿is￿measured￿by￿the￿KLE.￿The￿measured￿value
is￿then￿sent￿to￿the￿LIM￿as￿an￿analog￿signal.￿The￿LIM￿then￿sends￿the￿calculated￿value￿via￿PT-CAN￿to
other￿control￿units.
Emergency￿charging
If￿both￿the￿high-voltage￿and￿the￿12 V￿battery￿are￿discharged,￿the￿emergency￿charging￿of￿the￿12 V
battery￿is￿automatically￿started￿when￿the￿charging￿cable￿is￿connected.￿As￿the￿two￿batteries￿are
discharged,￿there￿is￿also￿no￿voltage￿supply￿of￿the￿12 V￿vehicle￿electrical￿system￿and￿the￿LIM￿is￿in￿this
case￿initially￿not￿working.￿So￿that￿the￿LIM￿can￿start￿communication￿with￿the￿charging￿station￿and￿thus
also￿the￿charging￿procedures,￿a￿special￿voltage￿supply￿of￿the￿LIM￿is￿required.￿The￿voltage￿supply￿for
the￿LIM￿is￿effected￿in￿this￿case￿by￿the￿pilot￿line.￿The￿energy￿used￿by￿the￿pilot￿line￿is￿so￿low￿that￿the
voltage￿evaluation￿for￿the￿EVSE￿is￿not￿affected.
In￿order￿to￿identify￿emergency￿charging￿the￿voltage￿value￿of￿terminal￿30F￿is￿evaluated.￿The￿evaluation
circuit￿is￿located￿in￿the￿LIM.￿If￿the￿voltage￿value￿of￿terminal￿30F￿falls￿below￿6 V￿and￿the￿pilot￿line￿is
correctly￿connected,￿the￿evaluation￿circuit￿drags￿the￿voltage￿value￿on￿the￿pilot￿line￿to￿a￿value￿of￿6 V.
This￿voltage￿value￿corresponds￿to￿the￿message￿at￿the￿charging￿station￿that￿the￿vehicle￿is￿ready￿for
charging.￿The￿charging￿station￿is￿thus￿prompted￿to￿apply￿the￿vehicle￿voltage.
6.4.4.￿Convenience￿charging￿electronics￿(KLE)
Convenience￿charging￿electronics￿for￿combo￿charging￿at￿7.4 kW￿AC￿charging￿power
The￿KLE￿version￿installed￿for￿combo￿charging￿at￿7.4 kW￿AC￿charging￿power￿is￿responsible￿for￿the
contact￿of￿all￿HV￿connections￿and￿the￿housing￿of￿the￿two￿DC￿switch￿contactors.
In￿this￿case￿the￿KLE￿has￿no￿rectifier￿switching￿for￿the￿conversion￿of￿AC￿voltage￿to￿direct￿current
voltage.￿The￿conversion￿of￿the￿AC￿voltage￿to￿direct￿current￿voltage￿takes￿place￿in￿the￿charging￿station.
The￿full￿power￿of￿the￿AC￿network￿is￿used￿(all￿three￿phases).￿If￿all￿prerequisites￿for￿charging￿the￿high-
voltage￿battery￿are￿satisfied,￿the￿LIM￿switches￿on￿the￿two￿switch￿contactors￿in￿the￿KLE.￿The￿charging
station￿then￿provides￿the￿direct￿current￿voltage￿at￿the￿output￿for￿charging￿the￿high-voltage￿battery.￿The
direct￿current￿voltage￿reaches￿the￿KLE￿via￿the￿charging￿socket￿and￿the￿high-voltage￿cables.￿The￿direct
current￿voltage￿is￿directed￿via￿the￿high-voltage￿cables￿to￿the￿EME￿and￿then￿finally￿to￿the￿high-voltage
battery.￿The￿high-voltage￿cables￿and￿the￿switch￿contactors￿are￿designed￿for￿an￿electrical￿power￿of￿up
to￿50 kW.
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