A method for the handling of a malfunction of a battery charger for the recharge of a low voltage battery of a vehicle with an electric powertrain, in particular for the limitation of a rotational speed of a supply fan of a cooling air flow through one or more radiant elements of one or more thermal conditioning circuits

Abstract

Disclosed herein is a method for the handling of a malfunction of a battery charger for the recharge of a first battery of a vehicle with an electric powertrain, the electric powertrain comprising one or more electric traction motors, each being operatively connected to one or more corresponding drive wheels, and a second battery configured to power said one or more electric traction motors, the second battery having a higher supply voltage than the first battery, said battery charger being powered by said second battery for the recharge of said first battery. The vehicle comprises at least one thermal conditioning circuit comprising a radiant element through which a heat transfer fluid flows, and a fan configured to supply, through each radiant element, an air flow rate in a heat exchange relationship with the corresponding heat transfer fluid, the fan being driven in rotation by an electric motor powered by the first battery. Thanks to the method according to the invention it is thus possible to increase the driving range of the vehicle in malfunction conditions of the battery charger, maintaining the operation of the high-voltage network as long as possible thanks to the rotational speed of the fan being limited, wherein the limitation takes into account the more challenging conditions of thermal power rejection.

Description

[0001] "A method for the handling of a malfunction of a battery charger for the recharge of a low voltage battery of a vehicle with an electric powertrain , in particular for the limitation of a rotational speed of a supply fan of a cooling air flow through one or more radiant elements of one or more thermal conditioning circuits"

[0002] ★ ★ ★ ★

[0003] TEXT OF THE DESCRIPTION

[0004] Field of the Invention

[0005] The present invention relates to vehicles having an electric powertrain, in particular to BEVs . The invention was developed with particular reference to the thermal management of the vehicle , speci fically to the handling of a supply fan of a cooling air flow rate through one or more radiant elements of one or more thermal conditioning circuits on board the vehicle .

[0006] Prior Art

[0007] A vehicle with an electric powertrain of the BEV (Battery Electric Vehicle ) type comprises two electrical power supply networks , including a high-voltage network ( e . g . 800 V) configured to propel the vehicle and powered by a high-voltage battery, and a low-voltage network ( e . g . 12 V) powered by a low-voltage battery which supplies some of the non-propulsive users , such as e . g . an electric motor for actuating a cooling fan which supplies air through one or more radiant elements of the vehicle ( typically a radiator traversed by a coolant and a condenser of a refrigeration cycle circuit ) , and one or more electric actuators of the high-voltage contactors which establish the electrical connection between the high-voltage battery and one or more electric traction motors of the electric powertrain of the vehicle .

[0008] The high-voltage battery is charged by the electric traction motors during the operation in regeneration mode , and by an external charging network when the vehicle is connected to a charging station . The low- voltage battery can be recharged only by means of a DC- DC battery charger on board the vehicle , which is powered by the high-voltage battery .

[0009] I f the DC-DC battery charger which is configured to recharge the low-voltage battery is in such mal function conditions that it becomes impossible to recharge the low-voltage battery, the functions performed by the users of the low-voltage battery remain available as long as the state of charge of the low-voltage battery allows for it . When the charge of the low-voltage battery is depleted, said functions cease to be available , and this implies the immediate stop of the vehicle and the impossibility to restart it , irrespective of the state of charge of the high-voltage battery, since the depletion of the charge of the low-voltage battery also causes the interruption of the supply to the actuators of the high-voltage contactors , thereby opening the electrical circuit which connects the high-voltage battery to the one or more electric traction motors .

[0010] In the prior art , the mal function condition of the DC-DC battery charger which is configured to recharge the low-voltage battery is not controlled in the evolution thereof . In other words , the evolution of the discharge of the low-voltage battery in mal function conditions of the DC-DC battery charger is left free to evolve without considering the consequences of such choice on the driving range of the vehicle .

[0011] Obj ect of the Invention

[0012] The invention aims at solving the technical problem outlined in the foregoing . Speci fically, the obj ect of the present invention is to provide a method which enables handling a mal function condition of the DC-DC battery charger of a vehicle with an electric powertrain, while maintaining, for as long as possible, the electrical supply to the one or more electric traction motors by the high-voltage battery .

[0013] Summary of the Invention

[0014] The obj ect of the invention is achieved by a method having the features set forth in one or more of the claims that follow, which form an integral part of the technical disclosure provided herein in relation to the invention .

[0015] Brief Description of the Drawings

[0016] The invention will now be described with reference to the annexed Figures , which are provided by way of non-limiting example only and wherein :

[0017] - Figure 1 shows a block diagram exempli fying a method according to the invention, with particular reference to a preferred embodiment , and Figure 1A shows a block diagram corresponding to a detail of the method shown in Figure 1 ,

[0018] - Figures 2 to 10 correspond to block diagrams showing steps and / or aspects of the method according to the invention .

[0019] Detailed Description

[0020] By way of general premise , the method according to the invention can be applied to a vehicle with an electric powertrain comprising one or more electric traction motors , each being operatively connected to one or more corresponding drive wheels , and a high-voltage battery ( e . g . 800 V) which is configured to propel the vehicle and to power the one or more electric traction motors . On board the vehicle , according to what has been set forth at the beginning of the present description, there is provided a low-voltage battery ( e . g . 12 V) configured to power non-propulsive users . Generally speaking, the low-voltage battery ( also denoted as " first battery" in the following) has a supply voltage which is (much) lower than the high-voltage battery ( also denoted as " second battery" in the following ) . Moreover, the first battery may only be recharged by means of a DC-DC battery charger which is powered by the second battery, i . e . which draws the electrical power for recharging the first battery from the second battery . On the other hand, the second battery may be charged both by the one or more electric traction motors during an operation in regeneration mode , and - as is commonly known - by connecting the vehicle to a charging station .

[0021] Said vehicle therefore comprises a high-voltage network configured to propel the vehicle and powered by the second battery, and a low-voltage network powered by the first battery and configured to supply some of the non-propulsive users , i . a . the electrical actuators of the high-voltage contactors which enable a transit of electrical current from the second battery .

[0022] Moreover, the vehicle comprises one or more thermal conditioning systems with a heat trans fer fluid, each comprising a radiant element through which a heat trans fer fluid flows ( the radiant element operating a cooling of the heat trans fer fluid) , and a fan configured to supply, through each radiant element , an air flow rate in a heat exchange relationship with the corresponding heat trans fer fluid, wherein the fan is driven in rotation by an electric motor powered by said first battery . Generally speaking, there may be present one or more circuits with a heat trans fer fluid which is not subj ect to phase changes , and comprising a single radiator for all such circuits ( i . e . , each circuit converges into the radiator for rej ecting the thermal power absorbed by the heat trans fer fluid towards the external environment - the heat trans fer fluid flows through the radiator ) , and a refrigeration cycle circuit traversed by a refrigerant fluid which is subj ect to phase changes along the circuit , wherein the refrigeration cycle circuit comprises a cabin evaporator wherein the refrigerant fluid is subj ect to a phase change from liquid to gas , and a condenser which rej ects the cooling power absorbed by the refrigerant fluid during evaporation, and within which the refrigerant fluid is subj ect to a phase change from gas to liquid .

[0023] Examples of vehicles with such a configuration are described, for example , in the Italian Industrial Invention Patent Applications 102024000003928 , 102024000015349 , 102024000016162 .

[0024] This being said, the invention defines a method for the handling of a mal function of the battery charger for the recharge of the first battery of a vehicle of the type under consideration, the method including, upon the occurrence of a mal function condition of the battery charger such as to impede the recharging of the first battery and for each thermal conditioning circuit :

[0025] - determining a state of charge ( SOC - in the following associated with the reference SOCLv_Batt) o f the first battery,

[0026] - determining a temperature of an environment in a heat exchange relationship with the heat trans fer fluid of the thermal conditioning circuit ,

[0027] - determining a limit value of rotational speed o f the fan as a function of the state of charge of the first battery and of the temperature of the environment being in a heat exchange relationship with the heat trans fer fluid of the thermal conditioning circuit , the method further including defining a global limit value of rotational speed of the fan nFANsPd_Lim as the greatest of the limit values of rotational speed determined for each thermal conditioning circuit .

[0028] Once the global limit value of rotational speed o f the fan nFANsPd_Lim has been determined, the method includes controlling the fan according to the global limit value of rotational speed nFANsPd_Lim. This includes limiting the rotational speed of the fan to the global limit value of rotational speed nFAwsPd_ Lim •

[0029] The method according to the invention is very flexible , since it may be applied to a general configuration of a vehicle with an electric powertrain, irrespective of the number or of the type of the thermal conditioning circuits , i . e . irrespective of the number of the radiant elements , provided that they are supplied with an air flow rate supplied by the same fan .

[0030] By way of example , Figure 1 shows a multiple block diagram, wherein reference 1 generally denotes the implementation of the method according to the invention, whereas the further references denote :

[0031] - the implementation of the method according to the invention with respect to a thermal conditioning circuit of the second battery ( reference 2 ) , which is a circuit with a heat trans fer fluid - comprising one or more circulation pumps - wherein the environment in a heat exchange relationship with the heat trans fer fluid comprises the same second battery,

[0032] - the implementation of the method according to the invention with respect to a thermal conditioning system of one or more traction units ( reference 4 ) , which is a circuit with a heat trans fer fluid - comprising one or more circulation pumps - wherein each traction unit comprises an electric traction motor, an inverter operatively associated with the electric traction motor and a transmission connecting the electric traction motor to one or more corresponding drive wheels , the transmission including a transmission lubricant , and wherein the environment in a heat exchange relationship with the heat trans fer fluid comprises - for each traction unit - the inverter, the electric traction motor and the transmission, in particular the transmission lubricant ( speci fically, there is present a heat exchanger for the transmission lubricant , which is traversed - in addition to the transmission lubricant - also by the heat trans fer fluid) ;

[0033] - the implementation of the method according to the invention with respect to a re frigeration cycle air conditioning system of a passenger compartment of the vehicle ( reference 6 ) - thus a thermal conditioning circuit through which a refrigerant fluid circulates which is subj ect to phase changes - comprising a cabin evaporator through which a refrigerant fluid circulates which is subj ect to a phase change from liquid to gas , and wherein the radiant element comprises a condenser through which the refrigerant fluid circulates and is subj ect to a phase change from gas to liquid, and wherein the environment includes an external environment in a heat exchange relationship with said condenser, since the air flow rate impinging upon the condenser ( and being supplied by the fan) comes from the external environment .

[0034] As observed in the foregoing, in preferred embodiments the circuits associated with references 2 and 4 share the same radiant element ( a radiator ) , whereas the condenser of the circuit associated with reference 6 ( refrigeration cycle air conditioning system) is independent , but it is installed in a single radiant pack together with the radiator of the circuits 2 , 4 , preferably positioned in front of the radiator in the direction of forward motion of the vehicle (whereas the fan is preferably arranged behind the radiator in the direction of forward motion of the vehicle ) . In other words , from front to rear, the sequence comprises the condenser, the radiator and the fan .

[0035] Moreover, it should be noted that the refrigeration cycle air conditioning system may be a part (and generally in BEVs it is a part) of a larger and more branched refrigeration circuit, comprising further evaporation devices in a heat exchange relationship with the heat transfer fluid flowing through the cooling circuit of the second battery (2) , thereby implementing a heat exchange device which is commonly known as chiller .

[0036] Each of the implementations 2, 4, 6 is shown in detail in the following Figures 2 to 10.

[0037] Referring to Figure 2, diagram 10, in the case of an implementation on a thermal conditioning circuit 2 of the second (high-voltage) battery, there is defined a first limit value of rotational speed nFANsPd_Batt_Lim which corresponds to the output of a switch SW10. The switch SW10 is subject to a control variable DCDC_Critical_Error , which acquires the logic state "1" (TRUE) upon the occurrence of a malfunction of the battery charger configured to recharge the first battery, and the logic state "0" (FALSE) when there is no occurrence of a malfunction of the battery charger configured to recharge the first battery. The reference SWC indicates the condition which depends on the logic state of the variable DCDC_Critical_Error which controls the switch SW10 (in the present case SWC: DCDC_Critical_Error = TRUE) .

[0038] Upon the occurrence of a malfunction, i.e. in the case of interest for the method according to the invention, the output of the switch SW10 corresponds to what is shown in Figure 2, wherein the limit value nFANsPd_Batt_Lim applicable to the fan which supplies air to the radiant elements (and particularly to the radiant element - the radiator - of the thermal conditioning circuit of the second battery) is assumed to be equal to the output data item nFANs d_Batt_LimRaw of a map MIO, corresponding to a limit value of rotational speed determined as a function of a state of charge SOCLv_Batt of the first ( low- voltage ) battery, and of a temperature Tnv_Batt of the second battery, since the environment in a heat exchange relationship with the heat trans fer fluid of the circuit 2 corresponds to the same second battery . The map 10 provides the limit value nFANsPd_Batt_LimRaw by means of curves function of the state of charge SOCLv_Batt and parameteri zed with respect to the temperature value Tnv_Batt . By way of example , the map MI O of Figure 2 shows the qualitative evolution of four curves nFANsPd_ Batt LimRaw SOCLv_Batt parameteri zed as a function of temperature values of the second battery THv_Batt_i , THv_Batt_2 , THv_Batt_3 , Tnv_Batt_4 , mentioned in an order of increasing temperature ( thus THV_Batt_l < Tnv_Batt_2 < ThV_Batt_3 < Tnv_Batt_4 ) • Qualitatively, the limit value nFANsPd_ Batt LimRaw decreases with the decrease in the state of charge SOCLv_Batt of the first battery, since for low values of state of charge it is necessary to limit the absorption of electrical power by the first battery, thus it is necessary to reduce the rotational speed of the fan (which limits the absorption of power by the corresponding electric motor ) , and it increases with the increase in temperature Tnv_Batt in such a way as to progressively raise the limit of rotational speed of the fan as the temperature rises , and as to avoid damages to the high-voltage battery ( as a consequence , there is an increase in the air flow rate supplied to the radiator configured to rej ect thermal power in the circuit 2 ) . In Figure 2 there is even shown, for the temperature THv_Batt_4 , the case of a limit nFANsPd_Batt_LimRaw which does not vary as S OCLv_Batt varies , thereby showing the case of a battery temperature which is so high as to make it impracticable to implement a limitation, not even at very low levels of state of charge S OCLv_Batt . In the opposite case , wherein no mal function occurs , the output of the switch SW10 corresponds to an alternative to what is shown in Figure 2 , wherein the limit value nFANsPd_Batt_Lim applicable to the fan is assumed to be equal to a limit value Battery_FANSpd_NoLim of rotational speed which does not depend on SOCLv_Batt and Tnv_Batt, but which on the contrary is constant and available as such on data networks on board the vehicle .

[0039] With reference to Figure 3 , diagram 20 , in the case of an implementation on a thermal conditioning circuit 4 of one or more traction units of the electric powertrain ( including at least a second circulation pump ) , wherein each traction unit comprises an electric traction motor, an inverter operatively associated to the electric traction motor and a transmission which connects the electric traction motor with one or more corresponding drive wheels , and wherein the transmission comprises a transmission lubricant , there is defined a second limit value of rotational speed nFANsPd_Trc_Lim which corresponds to the output of a switch SW20 . The switch SW20 is subj ect , in the same way as the switch SW10 , to the control variable DCDC_Critical_Error , which acquires the logic state " 1" ( TRUE ) upon the occurrence of a mal function of the battery charger configured to recharge the first battery, and " 0" ( FALSE ) when no mal function occurs of the battery charger configured to recharge the first battery . Again, reference SWC denotes the condition which depends on the logic state of the variable DCDC_Critical_Error which controls the switch SW20 ( in the present case , SWC : DCDC_Critical_Error = TRUE ) .

[0040] Upon the occurrence of a mal function, i . e . in the case of interest for the method according to the invention, the output of the switch SW20 corresponds to what is shown in Figure 3 , wherein the limit value nFANsPd_Trc_Lim applicable to the fan is assumed to be equal to a limit value nFANsPd_Trc_LimRaw corresponding to the greatest value (block 22 , MAX ) out of a first limit value of rotational speed nFANspd_inv_Lim depending on the state of charge SOCLv_Batt of the first battery and on a temperature of the inverter TFnv, a second limit value of rotational speed nFANspd_Mot_Lim depending on the state of charge SOCLv_Batt of the first battery and on a temperature of the electric traction motor TMOB , and a third limit value of rotational speed nFANspd_Trnsmoii_Lim depending on the state of charge of the first battery SOCLv_Batt and on a temperature of the transmission lubricant TTrnsmoii . This means that the limit value nFANsPd_ Trc LimRaw is selected to be equal to the limit value resulting from the most challenging conditions , in such a way as to ensure the required thermal conditioning to the corresponding one or more traction components .

[0041] The dependence on the temperatures TFnv, TMot, T TrnsmOil is due to the fact that the environment in a heat exchange relationship with the heat trans fer fluid of the thermal conditioning circuit of the one or more traction units comprises the inverter, the transmission lubricant and the electric traction motor .

[0042] In the opposite case , wherein no mal function occurs , the output of the switch SW20 corresponds to an alternative to what is shown in Figure 3 , wherein the limit value nFANspd_Trc_Lim applicable to the fan which supplies air to the radiator (which is preferably shared with the circuit 2 , as stated in the foregoing) of the one or more traction components is assumed to be equal to a limit value of rotational speed Traction_FANSpd_NoLim which does not depend on SOCLv_Batt and THv_Batt, but which on the contrary is constant and available as such on data networks on board the vehicle .

[0043] The following Figures 4 to 6 show the determination Of the limit values nFANSpd_Inv_Lim, nFANSpd_Mot_Lim, nFANSpd_Tmsmoii_Lim as a function of the temperatures Tinv, TMOF , TTrnsmoii ( respectively) and of the state of charge S OClV_Batt •

[0044] Referring to Figure 2 , diagram 30 , the limit value nFANsPd_inv_Lim corresponds to the output data item of a map M30 which provides the value nFANsPd_inv_Lim as a function of the state of charge SOCLv_Batt of the first ( low- voltage ) battery, and of the temperature of the inverter T inv . In the method according to the invention, the temperature value of the inverter Tinv used as an input data item for the map M30 corresponds to the highest (block 32 , MAX ) out of the temperature values of the inverters detected for each inverter of the powertrain . By way of example , Figure 4 refers to a vehicle with a quad-motor powertrain comprising four traction units , each including an inverter, an electric traction motor and a transmission with a transmission lubricant . The indexes A, B, C, D associated with the references in Figure 4 individually denote the traction units and the respective components : in other words , the temperature T inv is equal to the highest out of the values Tinv_A, Tinv_B, Tinv_c, Tinv_D of the four inverters .

[0045] The map M30 provides the limit value nFANsPd_inv_Lim by means of curves function of the state of charge SOCLv_Batt and parameteri zed with respect to the temperature value of the inverter Tinv . By way of example , the map M30 in Figure 4 shows the qualitative evolution of four curves nFANsPd_inv_Lim- S OCLv_Batt parameteri zed as a function of temperature values of the inverter Tinv_i, Tinv_2 , Tinv_3, Tinv_4 mentioned in an order of increasing temperature ( thus Tinv_i < Tinv_2 < Tinv_3 < Tinv_4 ) . Qualitatively, the limit value nFANsPd_inv_Lim decreases with the decrease in the state of charge SOCLv_Batt of the first battery, since for low values of state of charge it is necessary to limit the absorption of electrical power by the first battery, and thus to reduce the rotational speed of the fan, and it increases with the increase in the temperature TFnvin such a way as to progressively raise the limit of rotational speed of the fan as the temperature of the inverter rises ( thus rej ecting more thermal power through the radiator, but absorbing more electrical power for actuating the fan) , and as to avoid damages to the same inverter .

[0046] With reference to Figure 5 , diagram 40 , the limit value nFANsPd_Mot_Lim corresponds to the output data item of a map M40 which provides the value nFANsPd_Mot_Lim as a function of the state of charge SOCLv_Batt of the first ( low- voltage ) battery, and of the temperature of the electric traction motor TMOB . The map M40 provides the limit value nFANs d_Mot_Lim by means of curves function of the state of charge SOCLv_Batt and parameteri zed with respect to the temperature value of the electric traction motor TMot .

[0047] In the method according to the invention, the temperature value of the electric traction motor TMOB used as an input data item for the map M40 corresponds to the highest (block 42 , MAX) out of the temperature values of the electric traction motors detected for each electric traction motor of the powertrain . By way of example , Figure 5 refers again to the vehicle with a quad-motor powertrain, comprising four traction units each including an inverter, an electric traction motor and a transmission with a transmission lubricant . The indexes A, B, C, D associated with the references in Figure 4 individually denote the traction units and the respective components : therefore , the temperature TMOB is equal to the greatest value out of the values TMot_A, TMot_B, TMot_c, TMot_D of the four electric traction motors .

[0048] By way of example , the map M40 in Figure 5 shows the qualitative evolution of four curves nFANsPd_Mot_Lim- SOCLv_Batt parameteri zed as a function of temperature values of the electric traction motors TMot_i, TMot_2 , TMot_3, TMot_4 , mentioned in an order of increasing temperature ( thus , TMot_i < TMot_2 < TMot_3 < TMot_4 ) . Qualitatively, the limit value nFANsPd_Mot_Lim decreases with the decrease in the state of charge SOCLv_Batt of the first battery, since for low values of state of charge it is necessary to limit the absorption of electrical power by the first battery, and therefore to reduce the rotational speed of the fan, and it increases with the increase in the temperature TMOB in such a way as to progressively raise the limit of rotational speed of the fan as the temperature of the electric traction motor rises ( rej ecting more thermal power by means of the radiator, but absorbing more electrical power for actuating the fan) , and as to prevent damages to the electric traction motor of the traction unit .

[0049] With reference to Figure 6 , diagram 50 , the limit value nFANsPd_Trnsmoii_Lim corresponds to the output data item of a map M50 which provides the value nFANsPd_Trnsmoii_Lim as a function of the state of charge SOCLv_Batt of the first ( low- voltage ) battery and of the temperature of the transmission lubricant TTrnsmoii .

[0050] In the method according to the invention, the temperature value of the electric traction motor TTrnsmoii used as an input data item for the map M50 corresponds to the highest (block 52 , MAX) out of the temperature values of the transmission lubricant detected for each transmission . By way of example , Figure 6 refers again to the vehicle with a quad-motor powertrain, comprising four traction units each including an inverter, an electric traction motor and a transmission with a transmission lubricant . The indexes A, B, C, D associated with the references in Figure 4 individually denote the traction units and the respective components ; therefore , the temperature TMot is equal to the highest out of the Values TTrnsmOil_A, TTrnsmOil_B, TTrnsmOil_C, TTrnsmOil_D Of the transmission lubricants of the four transmissions .

[0051] The map M50 provides the limit value nFANsPd_Trnsmoii_Lim by means of curves function of the state of charge SOCLv_Batt and parameteri zed with respect to the temperature value of the transmission lubricant TTrnsmoii . By way of example , the map M50 of Figure 6 shows the qualitative evolution of four curves nFANsPd_ TrnsmOil Lim SOCLv_Batt parameteri zed as a function of temperature values of the transmission lubricant TTrnsmoii_i, TTrnsmoii_2 , TTmsmoii_3, TTrnsmoii_4 , mentioned in an order of increasing temperature ( thus TTrnsmOii_i < TTrnsmOii_2 < TTrnsmOii_3 < TTrnsm0ii_4 ) . Qualitatively, the limit value nFANsPd_TrnSmoii_Lim decreases with the decrease in the state of charge SOCLv_Batt of the first battery, since for low values of state of charge it is necessary to limit the absorption of electrical power by the first battery, and thus to reduce the rotational speed of the fan, and it increases with the increase in the temperature TTrnsmoii, in such a way as to progressively raise the limit of rotational speed of the fan as the temperature of the transmission lubricant rises ( rej ecting more thermal power through the radiator, but absorbing more electrical power for actuating the fan) and as to avoid damages to the same transmission .

[0052] With reference to Figure 7 , diagram 60 , in the implementation of the method according to the invention on the air conditioning system 6 of the passenger compartment of the vehicle , there is defined a third limit value of rotational speed nFANsPd_cabEvP_Lim which derives from the request for cooling thermal power demanded from the cabin evaporator, and which consequently influences the request for rej ecting thermal power demanded from the condenser, which is in turn connected to the rotational speed of the fan . The environment in a heat exchange relationship with the heat trans fer fluid ( in the present case , the refrigerant fluid in the condenser ) is , as stated in the foregoing, the external environment .

[0053] The third limit value of rotational speed nFANsPd_cabEvp_Lim corresponds to the output of a switch SW60 . The switch SW60 is subj ect , in the same way as the switches SW10 , SW20 , to the control variable DCDC_Critical_Error , which acquires the logic state " 1" ( TRUE ) upon the occurrence of a mal function o f the battery charger configured to recharge the first battery, and the logic state " 0" ( FALSE ) when there is no mal function of the battery charger configured to recharge the first battery . Again, the reference SWC denotes the condition which depends on the logic state of the variable DCDC_Critical_Error which controls the switch SW60 ( in the present case , SWC : DCDC_Critical_Error = TRUE ) .

[0054] Upon occurrence o f a mal function, i . e . in the case of interest for the method according to the invention, the output of the switch SW60 corresponds to what is shown in Figure 7 , wherein the limit value nFANSpd_cabEvp_Lim applicable to the fan is assumed to be equal to a raw limit value nFANSpd_cabEvp_ LimRaw •

[0055] In the opposite case , wherein no mal function occurs , the output of the switch SW60 corresponds to an alternative to what is shown in Figure 7 , wherein the limit value nFANspd_cabEvp_Lim applicable to the fan is assumed to be equal to a limit value of rotational speed CabinEvaporator_FANSpd_NoLim which does not depend on SOCLv_Batt or on a temperature of the external environment TAmb, but which, on the contrary, is constant and available as such on the data network on board the vehicle .

[0056] The following Figure 8 , diagram 70 , represents the determination of the raw value nFANSpd_cabEvp_LimRaw which, as described in the foregoing, comes into play upon the occurrence of a mal function of the battery charger . In more detail , the raw value nFANSpd_cabEvp_LimRaw (which becomes the third limit value nFANsPd_cabEvp_Lim upon occurrence of a mal function) comprises :

[0057] - a nominal limit value nFANSpd_cabEvp_LimNorm depending on the state of charge of the first battery SOCLv_Batt and on a temperature of the external environment TAmb i f there is no request for thermal conditioning of the passenger compartment of the vehicle that requires priority ful filment ,

[0058] - a priority limit value nFANSpd_cabEvp_LimsPec depending on the state of charge of the first battery SOCLv_Batt and on the temperature of the external environment TAmb i f there is at least one request for thermal conditioning of the passenger compartment of the vehicle that requires priority ful filment . The priority limit value nFANSpd_cabEvp_LimsPec is always higher than the nominal limit value nFANSpd_cabEvp_LimNorm under the same state of charge SOCLv_Batt of the first battery and under the same temperature TAmb of the external environment .

[0059] In Figure 8 , this is exempli fied by a switch SW70 which is subj ect to a control variable Special_Cabin_Conditioning_Active , which acquires the logic state " 1" ( TRUE ) when there is at least one request for thermal conditioning of the passenger compartment of the vehicle that requires priority ful filment , and " 0" ( FALSE ) when there is not at least one request for thermal conditioning of the passenger compartment o f the vehicle that requires priority ful filment . The reference SWC70 denotes the condition which depends on the logic state of the variable Special_Cabin_Conditioning_Active which controls the switch SW70 ( in the present case , SWC70 : Special_Cabin_Conditioning_Active = TRUE ) .

[0060] I f there is at least one request for thermal conditioning of the passenger compartment of the vehicle that requires priority ful filment ( Special_Cabin_Conditioning_Active = TRUE ) , the output of the switch SW70 corresponds to what is shown in Figure 8 , wherein the limit value nFANsPd_cabEvP_ LimRaw is assumed to be equal to the value nFANsPd_cabEvP_ LimSpec •

[0061] In the opposite case , wherein there is not at least one request for thermal conditioning of the passenger compartment of the vehicle that requires priority ful filment ( Special_Cabin_Conditioning_Active = FALSE ) , the output of the switch SW70 corresponds to an alternative to what is shown in Figure 8 , wherein the limit value nFANsPd_cabEvP_LimRaw applicable to the fan which supplies the cooling air flow rate through the condenser of the air conditioning system of the passenger compartment of the vehicle is assumed to be equal to the Value nFANSPd_CabEvP_LimNorm •

[0062] For the purposes of the method according to the invention, the at least one request for thermal conditioning of the passenger compartment of the vehicle that requires priority ful filment includes :

[0063] - a request for cooling the passenger compartment of the vehicle under conditions of external temperature above a threshold value , preferably above 30 ° C, even more preferably in combination with a request for an interior temperature of 18 ° C or less ( generally corresponding to imparting a "LO" temperature command on the dashboard of the thermal air conditioning system of the passenger compartment ) , which circumstance is typically combined with a handling which envisages minimi zing the time needed to meet the request by the control unit configured to manage the air conditioning system of the passenger compartment ,

[0064] - a request to de fog a glass surface of the vehicle , preferably a windshield of the vehicle . Also in this case , it is a circumstance which is typically combined to a handling which envisages minimi zing the time needed to meet the request by the control unit configured to manage the thermal conditioning system of the passenger compartment .

[0065] For the requests for thermal conditioning of the passenger compartment of the vehicle that require priority ful filment , it is therefore envisaged to request the maximum possible rotational speed of the fan ( together with the maximum rotational speed of the compressor for circulating the refrigerant fluid of the air conditioning system of the passenger compartment ) , since meeting such goals is considered as critical with respect to the comfort and / or the safety of the moving vehicle . With such premises , a limitation of the performances of the fan is generally incompatible with the needs connected to the comfort and / or the travel safety .

[0066] The following Figures 9 and 10 , diagrams 80 , 90 , show a preferred fashion of determining the limit values nFANSpd_CabEvp_LimNorm and nFANSpd_CabEvp_LimSpec , respectively . Both values are extracted from a corresponding map M80 ( nFANSpd_CabEvp_LimNorm ) , M90 ( nFANSpd_cabEvp_Limspec ) as a function of the state of charge SOCLv_Batt of the first ( low- voltage ) battery and of the temperature of the external environment TAmb . Both maps M80 , M90 provide the respective limit values nFANSpd_cabEvp_LimNorm and nFANsPd_cabEvp_Limspec by means of curves function of the state of charge SOCLv_Batt and parameteri zed with respect to the temperature value of the external environment TAmb . By way of example , the maps M80 , M90 of the Figures 9 , 10 show the qualitative evolution of four curves nFANSpd_CabEvp_LimNorm S OCLV_Batt and nFANSpd_CabEvp_LimSpec S OCLV_Batt parameteri zed as a function of temperature values of the external environment TAmb_i, TAmb_2 , TAmb_3, TAmb_4 , mentioned in an order of increasing temperature ( thus TAmb_i < TAmb_2 < TAmb_3 < TAmb_4 ) . Qualitatively, the limit values nFANSpd_CabEvp_LimNorm—S OCLV_Batt and nFANSpd_CabEvp_LimSpec—S OCLV_Batt decrease with the decrease in the state of charge SOCLv_Batt of the first battery, since for low values of state of charge it is necessary to limit the absorption of electrical power of the first battery, thus reducing the rotational speed of the fan, and they increase with the increase in temperature TAmb, in such a way as to always meet a request for cooling the passenger compartment upon the occurrence of high temperatures . In other words , i f the external temperature is higher , it is necessary to supply a greater air flow rate - which is necessarily warmer - through the condenser, in order to rej ect more thermal power by means of the same condenser, thus ensuring higher performances to the evaporator but absorbing more electrical power for actuating the fan . The comparison between the maps M80 and M90 clearly shows what has been set forth in the foregoing, i . e . that the priority limit value nFANsPd_cabEvp_Limspec is always higher than the nominal limit value nFANsPd_cabEvp_LimNorm under the same state of charge SOCLv_Batt of the first battery and under the same temperature TAmb of the external environment , in such a way as to have a greater air flow rate supplied by the fan through the condenser in presence of a request for thermal conditioning of the passenger compartment o f the vehicle that requires priority ful filment .

[0067] Finally, turning back to Figure 1A and concluding the presentation of the method according to the invention, having determined the limit values of rotational speed nFANSpd_Batt_Lim, nFANSpd_Trc_Lim, nFANSpd_CabEvp_Lim as a function of the needs and of the conditions of the individual thermal conditioning circuits 2 , 4 , 6 , the method according to the invention envisages defining the global limit value of rotational speed nFANsPd_Lim as the greatest of the values nFANSpd_Batt_Lim, nFANSpd_Trc_Lim, nFANSpd_cabEvp_Lim under consideration . It is in practice an operation of connecting the calculations operated on the individual thermal conditioning circuits 2 , 4 , 6 , due to the fact that the fan is only one for all radiant elements ( radiator and condenser) used for the thermal conditioning circuits 2 , 4 , 6 under consideration, thus it is necessary to select the limit - the greatest - value of rotational speed which involves the most demanding conditions of thermal power rej ection, in order to avoid damages due to overtemperature in the related components of the vehicle , or to avoid conditions of discomfort in the passenger compartment .

[0068] Thanks to the method according to the invention it is thus possible to increase the driving range of the vehicle despite a mal function condition of the battery charger, while maintaining the operation of the high- voltage network as long as possible thanks to the rotational speed of the fan being limited to the value nFANspd_Lim, with a consequent reduction of electrical power absorption from the first battery by the electric motor which actuates the fan . Generally, it should be noted that the method according to the invention may also operate , should circumstances require , on a single thermal conditioning circuit (with a heat trans fer fluid or a heat transfer liquid) : in such case , the global limit value nFANspd_Lim will be equal to the limit value calculated for that circuit .

[0069] Of course , the implementation details and the embodiments may amply vary with respect to what has been described and illustrated, without departing from the extent of the present invention, as defined in the annexed claims .

Claims

CLAIMS1 . A method for the handling a mal function of a battery charger for the recharge of a first battery of a vehicle with an electric powertrain, the electric powertrain comprising one or more electric traction motors , each operatively connected to one or more corresponding drive wheels , and a second battery configured to power said one or more electric traction motors , the second battery having a higher supply voltage than the first battery, said battery charger being powered by said second battery for the recharge of said first battery, the vehicle comprising at least one thermal conditioning circuit comprising a radiant element through which a heat trans fer fluid flows , and a fan configured to supply an air flow rate through each radiant element in a heat exchange relationship with the corresponding heat trans fer fluid, the fan being driven in rotation by an electric motor powered by said first battery, the method including, upon the occurrence of a mal function condition of said battery charger ( DCDC_Critical_Error = 1 ) such as to impede the recharging of said first battery and for each thermal conditioning circuit ,- determining a state of charge ( SOCLV_Batt ) of the first battery, determining a temperature ( THV_Batt , TInv_A, TInv_B, TInv_C, TInv_D, TMot_A, TMot_B, TMot_C, TMot_D, TTrnsmOil_A, TTrnsmOil_B, TTrnsmOil_C, TTrnsmOil_D, TAmb ) of an environment in a heat exchange relationshipwith the heat trans fer fluid of the thermal conditioning circuit ,- determining a limit value of rotational speed (nFANSpd_Batt_Lim, nFANSpd_Trc_Lim, nFANSpd_CabEvp_Lim) of the fan as a function of the state of charge of the first battery ( SOCLV_Batt ) and of said temperature ( THV_Batt , TInv_A, TInv_B, TInv_C, TInv_D, TMot_A, TMot_B, TMot_C, TMot_D, TTrnsmOil_A, TTrnsmOil_B, TTrnsmOil_C, TTrnsmOil_D, TAmb ) of the environment in heat exchange relationship with the heat trans fer fluid of the thermal conditioning circuit , the method further including defining a global limit value of rotational speed (nFANSpd_Lim) of the fan as the greater o f the limit values of rotational speed (nFANSpd_Batt_Lim, nFANSpd_Trc_Lim, nFANSpd_CabEvp_Lim) determined for each thermal conditioning circuit .2 . The method of Claim 1 , including controlling the fan according to the global limit value of rotational speed (nFANSpd_Lim) .3 . The method of Claim 1 or Claim 2 , wherein said least one thermal conditioning circuit includes a thermal conditioning circuit of said second battery, wherein said environment includes said second battery, so that that said temperature includes a temperature of said second battery ( THV_Batt ) , and wherein the radiant element comprises a radiator for cooling a of a heat trans fer liquid flowing through the thermal conditioning circuit of said second battery .4 . The method of any of the foregoing claims , wherein said at least one thermal conditioning circuit includes a thermal conditioning circuit of one or moretraction units of said electric powertrain, each traction unit comprising an electric traction motor, an inverter operationally associated with the electric traction motor and a transmission connecting the electric traction motor to one or more corresponding drive wheels , the transmission including a transmission lubricant , wherein said environment comprises the inverter, the transmission and the electric traction motor, so that that temperature comprises an inverter temperature ( TInv) , a transmission lubricant temperature ( TTrnsmOil ) and an electric traction motor temperature ( TMot ) , where said radiant element includes a radiator for cooling a heat trans fer fluid flowing in said thermal conditioning circuit of one or more traction units in a heat exchange relationship with the electric traction motor, the inverter and the transmission lubricant of each of said one or more traction units , and wherein said limit value of rotational speed (nFANSpd_Trc_Lim) is the greater value ( 22 ) among a first limit value of rotational speed (nFANSpd_Trc_Inv_Lim) depending on the state of charge of said first battery ( SOCLV_Batt ) and the inverter temperature ( TInv) , a second limit value of rotational speed (nFANSpd_Trc_Mot_Lim) depending on the state of charge of the first battery ( SOCLV_Batt ) and the temperature of the electric traction motor ( TMot ) , and a third limit value of rotational speed (nFANSpd_Trc_TrnsmOil_Lim) depending on the state of charge of the first battery ( SOCLV_Batt ) and the temperature of the transmission lubricant ( TTrnsmOil ) .5 . The method of Claim 4 , wherein :- the inverter temperature ( TInv) is the higher ( 32 ) among the inverter temperature values ( TInv_A, TInv_B, TInv_C, TInv_D) detected for each inverter of the powertrain,- the temperature of the electric traction motor ( TMot ) is the higher among the electric motor temperature values ( TMot_A, TMot_B, TMot_C, TMot_D) detected for each electric traction motor of the powertrain, the temperature of transmi ssion lubricant ( TTrnsmOil ) is the higher among the transmission lubricant temperature values ( TTrnsmOil_A, TTrnsmOil_B, TTrnsmOil_C, TTrnsmOil_D) detected for each transmission of the powertrain .6 . The method of any of the foregoing claims , wherein said at least one thermal conditioning circuit includes a refrigeration cycle air conditioning system of a vehicle cabin comprising a cabin evaporator through which a refrigerant fluid circulates which is subj ect to a phase change from liquid to gas , and wherein said radiant element comprises a condenser through which said refrigerant fluid circulates and is subj ect to a phase change from gas to liquid, and wherein said environment includes an external environment in a heat exchange relationship with said condenser, wherein said limit value of rotational speed (nFANSpd_CabEvp_Lim) for the refrigeration cycle air conditioning system includes :- a nominal limit value (nFANSpd_CabEvp_Lim_Norm) depending on the state of charge of said first battery ( SOCLV_Batt ) and an external environment temperature(TAmb) if there is no request for thermal conditioning of the vehicle cabin ( Special_Cabin_Conditioning_Active = 0) that requires priority fulfilment,- a priority limit value (nFANSpd_CabEvp_Lim_Spec) depending on the state of charge of the first battery (SOCLV_Batt) and the external environment temperature (TAmb) if there is at least one request for thermal conditioning ( Special_Cabin_Conditioning_Active = 1) of the vehicle cabin that requires priority fulfilment, the priority limit value (nFANSpd_CabEvp_Lim_Spec) being higher than the nominal limit value (nFANSpd_CabEvp_Lim_Norm) under the same state of charge of the first battery (SOCLV_Batt) and under the same external environment temperature (TAmb) .

7. The method of Claim 6, wherein the at least one request for thermal conditioning of the vehicle passenger compartment requiring priority fulfilment includes :- a request for cooling of the vehicle cabin under conditions of outside temperature above a threshold value, preferably above 30 °C, even more preferably in combination with a request for an interior temperature of 18 °C or less,- a request to defog a glass surface of the vehicle, preferably a windshield of the vehicle.

8. The method of Claim 2, wherein controlling the fan according to the global limit value of rotational speed (nFANSpd_Lim) includes limiting the rotational speed of the fan to the global limit value of rotational speed .

9. The method of any of Claims 4 to 8, wherein theradiator is the same for the thermal conditioning circuit of said second battery and the thermal conditioning circuit of one or more traction units .10 . The method of Claim 9 , wherein the condenser of the air conditioning system of the vehicle cabin is installed in front of said radiator in a direction of forward motion of the vehicle , and wherein the fan is installed behind said radiator in the direction of forward motion of the vehicle .

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