A method for managing the electrical power supply from a high-voltage battery to one or more electric traction motors of an electric powertrain of a vehicle during acceleration maneuvres from a standing start

Abstract

There is described a method for managing the supply of electrical power from a first battery to one or more electric traction motors of an electric powertrain of a vehicle during an acceleration maneuvre from a standing start, for example a drag-race maneuvre. According to the invention, it is possible to offer the driver the possibility to perform acceleration maneuvres from a standing start (drag-race or shorter-duration maneuvres) with a significantly more satisfying experience with respect to the normal performance-oriented driving modes, and to fully exploit the availability of electrical power of the system.

Description

[0001] "A method for managing the electrical power supply from a high-voltage battery to one or more electric traction motors of an electric powertrain of a vehicle during acceleration maneuvres from a standing start"

[0002] ★ ★ ★ ★

[0003] TEXT OF THE DESCRIPTION

[0004] Field of the Invention

[0005] The present invention regards vehicles having an electric powertrain, speci fically BEVs . The invention was developed with particular reference to the management of the electrical power supply to one or more electric traction motor of an electric powertrain of the vehicle during acceleration maneuvres from a standing start , speci fically maneuvres requiring the maximum propulsive thrust , such as e . g . a drag-race maneuvre .

[0006] Prior Art

[0007] In literature , the acceleration maneuvre known as drag-race acceleration is considered di f ferent from a simple acceleration from a standing start ( so-called " launch" acceleration) , since the former is an acceleration along a distance of a quarter of a mile ( 0- 400 m) , whereas the latter is an acceleration up to a speed of 100 km / h ( 0- 100 km / h) . Both maneuvres are performed in conditions of preload on the axles and on the drivetrain, e . g . with the assi stance of a so-called " launch-control" algorithm, which requires the simultaneous pressure of both the brake pedal and the accelerator pedal in order to reach the desired preload . The drag-race maneuvre may be considered as a speci fic instance of an acceleration maneuvre from a standing start .

[0008] The prior art envisages a plurality of launchcontrol algoritms , which are generally available for performance-oriented driving modes , and in general such algorithms are provided for managing a launch maneuvre with 0- 100 km / h acceleration; however, no algorithm is speci fic for the needs of a quarter-mile acceleration maneuvre ( drag-race maneuvre ) .

[0009] In the vehicles with an electric powertrain - especially BEVs - the missing special functions of the launch-control algorithms regarding the requirements of a quarter-mile acceleration has further and much more serious consequences in comparison with the vehicles with a thermal powertrain, primarily due to evolution phenomena of the components of an electric powertrain during a drag-race maneuvre ( as during any maneuvre ) , such phenomena not appearing in a traditional thermal powertrain .

[0010] The known launch-control algorithms aim at using the power available for propulsion as a function of the absorption of electrical power by the non-propulsive users , such as the conditioning of the high-voltage battery and the supply to the auxiliary systems of the vehicle . I f the non-propulsive users absorb power from the high-voltage battery, that power is not made available for propulsion, and therefore it is not possible for the vehicle to express the maximum acceleration potential . This is true both for proper drag-race maneuvres and for acceleration maneuvres from a standing start developing on shorter distances . Moreover this means that , with SOC, aging and temperature unvaried, the propulsive thrust changes every time as a function of the power absorption by the non-propulsive users , i . e . as a function of the thermal conditioning of the high-voltage battery or of the thermal conditioning of the passenger compartment of the vehicle , to keep to the examples mentioned in the foregoing .

[0011] Moreover, the known algorithms enable acceleration maneuvres with high power absorption - such as a launchcontrol or a drag-race maneuvres - essentially throughout the range of SOC level s of the high-voltage battery, i . e . down to very low SOC levels ( in some examples down to SOC = 30% ) . As a consequence , the vehicle acceleration is subj ected to a remarkable degradation in time , since - to make it simple - the limit of the discharge power of the high-voltage battery decreases as the SOC decreases ( and it increases as the temperature of the battery increases ) .

[0012] In any case , this results in a high variability in the acceleration performances and in an underexploitation of the discharge power of the high- voltage battery .

[0013] Obj ect of the Invention

[0014] The invention aims at solving the technical problems outlined in the foregoing . Speci fically, the obj ect of the invention consists in providing a method for managing the electrical power supply to one or more electric traction motors of an electric powertrain of a vehicle during acceleration maneuvres from a standing start , speci fically drag-race maneuvres , which maximi zes the use of the high-voltage battery while guaranteeing uni form acceleration performances and safeguarding the battery integrity .

[0015] Summary of the Invention

[0016] The obj ect of the invention is achieved by means o f a method having the features set forth in the claims that follow, which form an integral part of the technical disclosure provided herein in relation to the invention .

[0017] Brief Description of the Figures

[0018] The invention will now be described with reference to the annexed Figures , which are provided by way o f non-limiting example only and wherein :

[0019] Figure 1 and Figure 1 show T-SOC diagrams representative of aspects of the method according to the invention, wherein T is a temperature of a battery supplying one or more electric traction motors of the vehicle , and SOC is a state of charge of the same battery,

[0020] - Figure 3 is a flow diagram showing, with the premises of Figures 1 and 2 , a preferred embodiment of a method according to the invention,

[0021] - Figure 4 is a multiple time diagram showing the evolution of various parameters during an acceleration maneuvre from a standing start , wherein the method according to the invention is implemented, and

[0022] - Figure 5 shows a further aspect of the method according to the invention .

[0023] Detailed Description

[0024] As a general premise , the features of the method according to the invention wil l be explained with reference to Figures 1 and 2 as regards the definition of characteristic domains used in the deductions operated in the method according to the invention, and with reference to Figure 3 as regards the general implementation of a preferred embodiment .

[0025] Referring to Figure 1 , the method according to the invention is based on defining a domain of maximum availability of the electrical discharge power of a first battery of the electric powertrain ( speci fically a high- voltage battery, e . g . 800 V) , which supplies the one or more electric traction motors of the vehicle (which in the following will be denoted as "battery" , " first battery" or "high-voltage battery" indi f ferently) . Said domain is indicated as MPR in Figure 1 .

[0026] Within the domain MPR there is available an electrical discharge power which exceeds an electrical discharge power nominally supplied in driving modes which are not speci fically configured for executing acceleration maneuvres from a standing start of an amount PExtrahigher than a minimum power di f ference M^tra r the value whereof is decided as a function of the application. In a preferred embodiment, the latter driving mode corresponds to a performance-oriented driving mode, which is e.g. named "Race", so that the respective nominal maximum electrical discharge power is denoted as Ppr^pNomRace. Referring to the maximum availability of electrical discharge power of the high- voltage battery, the difference ^Psxtra is defined as a function of a short-term discharge power (e.g. 3 seconds) , which corresponds to the maximum possible discharge power, denoted in the following as PnvBim> specifically according to the expression

[0027] A D — pShLlm > pMaxNomRace

[0028] ‘ Extra ‘ HVB ‘Prop with

[0029] By defining the operational coordinates of the high-voltage battery as pairs of values SOC, T, wherein SOC is a current state of charge of the battery, and T is a current temperature of the battery, in turn it is possible to define the domain MPR as the locus of the operational coordinates wherein the relationship ^Psxtra > ^Psxtra holds true. As it is commonly known, to a first approximation the limit (or maximum) discharge powers of a high-voltage battery, among which PHVB™ , depend on the SOC and on the temperature T (i.e. on the operational coordinates) , so that also ^Ppxtra depends on the operational coordinates (SOC, T) of the battery.

[0030] As may be seen in Figure 1, the domain MPR of maximum availability of electrical discharge power of the battery is delimited by a lower state of charge limit SOCMin, by an upper state of charge limit SOCMax, by a first lower limit temperature curve TLowand by a first upper limit temperature curve Tcriticai. In preferred embodiments , i . e . in embodiments comprising most values of ^Psxtra chosen while designing the powertrain and the vehicle , the value SOCMinis chosen to equal 80% of the charge of the high-voltage battery, while the value SOCMaxis chosen to equal 100% of the charge of the high- voltage battery . Generally speaking, SOCMinis chosen in the range of 65%- 85% , more preferably of 75%- 85% , inclusive .

[0031] As regards the limit curves TLowand Tcritical, in the example shown in Figure 1 the first curve (TLow) generally has values which decrease as the SOC increases from SOCMinto SOCMax, to become stable at a constant value beyond a knee point SOCKcomprised between SOCMinand SOCMaxand di f ferent from both, whereas the curve Tcritical isahori zontal straight line on the T-SOC plane with constant values in the SOC range from SOCMinto SOCMax. In the example shown in Figure 1 , the curve Tcrtticaihas constant values as a function of the SOC and equal to 55 ° C, which is generally a critical (upper ) temperature for the high- voltage battery, whereas between SOCKand SOCMaxthe values of TLoware stable at 15 ° C, which is generally a temperature below which the high-voltage battery no longer guarantees the maximum nominal electrical discharge power Pprc^}NomRace. However, it shal l be borne in mind that generally the shape of the domain MPR depends on the design features of each battery, i . e . on the overall shape dictated by the upper and lower SOC limits and on the upper and lower temperature limits of the battery, and it can vary even appreciably with respect to what has been described and illustrated with reference to the examples of Figures 1 and 2 .

[0032] Referring to Figure 2 , within the domain MPR there are defined, according to the invention, a first subdomain CwPHR and a second sub-domain CwoPHR, both being internal to the domain MPR . The references used are also acronyms for a clearer reference and understanding o f the invention, and speci fically the first sub-domain CwPHR has the meaning of " Condi ti oning wi th (w / ) Pl ug High Regi on" , whereas the second sub-domain CwoPHR has the meaning of " Condi ti oning wi thout (w / out) Pl ug High Regi on" .

[0033] The first sub-domain CwPHR is delimited by the first upper limit temperature curve Tcriticaland by a second upper limit temperature curve TUpBand, wherein the first upper limit temperature curve has temperature values - the SOC being equal ( and in any case ) - which are higher than the temperature values of the second upper limit temperature curve TUpBand, whereas the second sub-domain CwoPHR is delimited by the second upper limit temperature curve TUpBandand by a third upper limit temperature curve Tnigti r wherein the third upper limit temperature curve Tntgh has temperature values - the SOC being equal ( and in any case ) - which are lower than the temperature values of the second upper limit temperature curve TUpBand - Preferably, the limits regarding the SOC of the first sub-domain CwPHR and of the second sub-domain CwoPHR correspond to the lower state of charge limit SOCMinand to the upper state of charge limit SOCMax, regardless of the temperature of the battery at SOCMinand SOCMax( thus , they are vertical segments on the plane T-SOC ) . As a function of the features of the high-voltage battery, it is possible to envisage SOC limits which are more restrictive than the limits of the domain MPR .

[0034] In this way, there is defined an activation domain AR as a domain ( sub-domain) internal to the domain MPR and resulting from a di f ference between the domain MPR of maximum availability of the battery electrical discharge power and the first and second sub-domains CwPHR and CwoPHR . On an operational level , the limits of the activation domain AR as regards the temperature of the battery are the curves THighand TLow, whereas the limits as regards the SOC correspond to the lower state of charge limit SOCMinand to the upper state of charge limit SOCMax.

[0035] According to the invention, the domains AR, CwPHR and CwoPHR correspond to loci of operational coordinates (SOC, T) of the high-voltage battery of the powertrain of the vehicle which determine, as a function of the position of the operational coordinates (SOC, T) of the high-voltage battery, different actions and reactions to a request by the vehicle driver for an acceleration maneuvre from a standing start, specifically a drag-race acceleration maneuvre on a quarter-mile distance.

[0036] The activation domain AR corresponds to a set of loci of operational coordinates (SOC, T) of the high- voltage battery based on which it is possible to enable the acceleration maneuvres from a standing start, specifically the drag-race maneuvre. In the context of the present disclosure, enabling the acceleration maneuvre may correspond: i) to a condition wherein the maneuvre is made available in response to a driver's request (for example by selecting a drag-race driving mode) , but it is not triggered yet: this is the case of the preferred embodiment shown in the Figures. The maneuvre is triggered when the driver of the vehicle actuates - in addition to the above request - an action specific for the purpose, e.g., as will be described shortly, by means of a simultaneous pressure of a brake pedal and of an accelerator pedal; ii) a condition wherein the maneuvre is made available and triggered when the driver forwards the request, e.g. by selecting the drag-race driving mode.

[0037] In the absence of other system faults, at the moment of triggering the drag-race maneuvre - following the action of the driver ( in the preferred instance i ) or meeting the request of the driver ( instance ii ) - a command is imparted to terminate the electrical power supply from the high-voltage battery to one or more non- propulsive users of the vehicle , other than the one or more electric traction motors . Generally speaking, in a vehicle having an electric powertrain said non- propulsive users include a thermal conditioning unit o f the high-voltage battery and a thermal conditioning unit of a passenger compartment of the vehicle , as well as a DC-DC converter and a further battery ( or low-voltage battery) having a voltage lower than the high-voltage battery . The low-voltage battery i s configured to supply non-propulsive users in the low-voltage circuit of the vehicle , and it is configured to be recharged by the high-voltage battery .

[0038] The first sub-domain CwPHR corresponds to a set of loci of operational coordinates ( SOC, T ) of the high- voltage battery, based on which the user' s request is rej ected, since the battery temperature is in a temperature range too high to deal with an acceleration maneuvre with a maximum delivery o f electrical power to one or more electric traction motors , and there is a risk of exceeding the critical temperature of the high- voltage battery before ending the acceleration maneuvre . The thermal conditioning, wherein the thermal conditioning in the domain CwPHR is a cooling of the battery, is therefore necessary, and it may consume a part of the SOC, therefore rapidly bringing the SOC below SOCMini f the vehicle is not connected to a charging station . Therefore , i f the operational coordinates of the high-voltage battery are located in the sub-domain CwPHR, the invention envisages rej ecting the request for the acceleration maneuvre from a standing start , while reporting a need of thermal conditioning of the battery through a connection to a charging station .

[0039] The second sub-domain CwoPHR corresponds to a set of loci of operational coordinates ( SOC, T ) of the high- voltage battery based on which the user' s request is substantially put on stand-by, without being rej ected . In this sub-domain, the battery temperature is in a temperature range which is still too high ( albeit not as high as in the domain CwPHR) , which may easily lead to exceeding the critical temperature of the high-voltage battery before ending the acceleration maneuvre with maximum delivery of electrical power to one or more electric traction motor without thermal conditioning . The thermal conditioning in the domain CwoPHR is again a cooling of the battery, but in this case the thermal conditioning will not lead to a consumption of a part o f the SOC which may bring the SOC below SOCMinin the absence of a connection of the vehicle to a charging station . Therefore , i f the operational coordinates of the high-voltage battery are located in the sub-domain CwoPHR, the invention envisages reporting a need of thermal conditioning of the battery with no connection to a charging station, and initiating the thermal conditioning of the battery . The driver of the vehicle is informed about the ongoing conditioning but , preferably, the vehicle can accelerate , albeit without the maximum availability of power, since it is not possible to terminate the supply to a non-propulsive user which requires a high absorption, such as the thermal conditioning unit of the high-voltage battery . Moreover, during the maneuvre it might be possible to reach temperatures for activating interventions for limiting ( derating) power, in order to safeguard the high-voltage battery . The supply o f electrical power to the electric traction motors is similar or substantially similar to the supply in a sports-oriented driving mode , such as e . g . a race mode .

[0040] In preferred embodiments of the invention, it i s also possible to define a first extra-domain CwoPLR and a second extra-domain CwPLR external to the domain MPR of maximum availability of electrical discharge power of the battery . The domain CwPLR is the dual domain of the domain CwoPHR, wherein the duality is only due to the temperature range which characteri zes the domain . As in the case of the sub-domains CwPHR and CwoPHR, the references used herein are simultaneously acronyms for a clearer reference and understanding of the invention, and speci fically the first extra-domain CwoPHR has the meaning of " Condi ti oning wi thout (w / out) Pl ug Low Regi on" , whereas the second extra-domain CwPHR has the meaning of " Condi ti oning wi th (w / ) Pl ug High Regi on" .

[0041] Speci fically, the first extra-domain CwoPLR i s delimited by the first lower limit temperature curve TLowand by a second lower limit temperature curve TLoBand, wherein the second lower limit temperature curve TLoBandhas temperature values - the SOC being equal ( and in any case ) - lower than the temperature values of the first lower limit temperature curve TLow, and the second extradomain CwPHR is delimited by the second lower limit temperature curve TLoBandand has temperature values - the SOC being equal ( and in any case ) - lower than the values of the second lower limit temperature curve TLoBand.

[0042] Preferably, the limits of the extra-domains CwoPLR and CwPLR in terms of SOC correspond to the lower state of charge limit SOCMinand to the upper state of charge limit SOCMax, regardless of the battery temperature at SOCMinand SOCMax( therefore , they are vertical segments on the plane T-SOC . As already mentioned for the subdomains CwPHR and CwoPHR, as a function of the high- voltage battery features it is possible to envisage limits regarding the SOC which are more restrictive with respect to the limits of the domain MPR .

[0043] The second extra-domain CwPLR - exactly in the same way as the sub-domain CwPHR - corresponds to a set of loci of operational coordinates ( SOC, T ) of the high- voltage battery based on which the user' s request is rej ected, since the battery temperature is in a temperature range which is too low to deal with an acceleration maneuvre with maximum delivery of electrical power to one or more electric traction motors without thermal conditioning, wherein the thermal conditioning in the domain CwPLR is a heating of the battery, and at the same time the thermal conditioning may consume an amount of SOC which would rapidly bring the SOC below SOCMinin the absence of a connection of the vehicle to a charging station . Therefore , i f the operational coordinates of the high-voltage battery are located in the extra-domain CwPLR, the invention envisages rej ecting the request for the acceleration maneuvre from a standing start, reporting a need for a thermal conditioning of the battery through connection to a charging station .

[0044] The first extra-domain CwoPLR corresponds - in the same way as the sub-domain CwoPHR - to a set of loci of operational coordinates ( SOC, T ) of the high-voltage battery, based on which the user' s request is - substantially - put on stand-by, without being rej ected . In this sub-domain the battery is in a temperature range which is still too low ( albeit not as low as in the domain CwoPHR) to deal with an acceleration maneuvre with maximum delivery of electrical power ( thus guaranteeing an extra-power higher than ^Psxtra ^ to one or more electric traction motor without thermal conditioning, wherein the thermal conditioning in the domain CwoPLR is again a heating o f the battery, but in this case the thermal conditioning will not consume an amount of SOC which would bring the SOC below SOCMinin the absence of a connection of the vehicle to a charging station . Therefore , i f the operational coordinates of the high-voltage battery are located in the sub-domain CwoPLR, the invention envisages reporting a need for the thermal conditioning of the battery without the connection to a charging station, and initiating the thermal conditioning of the battery . The driver of the vehicle is informed about the conditioning taking place but , preferably, the vehicle is able to accelerate , albeit without the maximum availability of power, since it is not possible to terminate the supply to a very absorbing non-propulsive user such as the thermal conditioning (heating) unit of the high-voltage battery . Moreover, at very low temperatures the discharge power of the high-voltage battery may not reach even the maximum nominal electrical discharge power Ppr^NomRace. The delivery of electrical power to the electric traction motors is similar or substantially similar to that of a sports-oriented driving mode , such as a race mode .

[0045] Always in the preferred embodiment described herein, it is possible to define a third extra-domain CwPLeR, always external to the domain MPR . The domain CwpLeR is delimited superiorly - as regards the SOC - by the lower state of charge limit SOCMin, regardless of the battery temperature . I f the operational coordinates ( SOC, T ) of the high-voltage battery are located in the extra-domain CwPLeR, the method comprises rej ecting the request for the acceleration maneuvres from a standing start , reporting the need of a connection to a charging station . This is due to the fact that the battery has a SOC lower than the lower limit value SOCMin, below which the minimum extra-power ^P^xtra isnolonger guaranteed regardless of the temperature .

[0046] The method according to the invention essentially enables ( again referring to the cases i ) and ii ) described in the foregoing) , the acceleration maneuvre from a standing start with maximum availability of power, while terminating the delivery to non-propulsive users when the operational coordinates of the high-voltage battery are located within the activation domain, whereas , i f the coordinates are located in any of the sub-domains or of the extra-domains , the method envisages bringing the operational coordinates towards ( and into ) the activation domain AR, by putting the maneuvre on stand-by (with a pre-conditioning of the battery - by either heating or cooling) when there is no need of a connection to a charging station ( CwoPHR, CwoPLR) , or it envisages a rej ection of the maneuvre with the simultaneous report of the need of a connection to a charging station ( CwPHR, CwPLR, CwPLeR) .

[0047] Figure 3 exempli fies the implementation of the method according to the invention in a preferred embodiment thereof . Reference 1 denotes the flow diagram as a whole and, implicitly, the method according to the invention . The method starts by imparting a command 2 which corresponds to forwarding a request for the acceleration maneuvre from a standing start , speci fically a drag-race maneuvre . In any case it should be noted that , although the description provided herein refers to a proper drag-race maneuvre ( i . e . a maneuvre which covers the distance of a quarter of a mile ) , the method according to the invention may be used for any acceleration maneuvre from a standing start wherein it is desired to obtain as high performances as possible , and to use the powertrain up to its limits .

[0048] The command 2 is forwarded to a first veri fication block 4 , which corresponds to veri fying the state of the high-voltage system of the vehicle , speci fically of the battery and of the one or more electric motors . In the presence of one or more faults - arrow FLT - the request of the driver is rej ected (block 6A) regardless of the operational coordinates of the high-voltage battery . The driver is informed by means of a warning which may comprise , for example , the appearance of a message ( or pop-up ) on the instrument cluster - box PU_DR_NA.

[0049] In the absence of faults , arrow NO_FLT , the veri fication focuses on the operational coordinates of the high-voltage battery, block 8 , and on the determination of the location of the operational coordinates with respect to the domains AR, CwPHR, CwoPHR, and, i f envisaged, CwoPLR, CwPLR, CwPLeR .

[0050] I f the operational coordinates of the high-voltage battery belong to any one of the domains CwPHR, CwPLR or CwPLeR ( ( SOC, T ) G CwPHR OR CwPLR OR CWPLeR) , the driver' s request is rej ected and the driver is informed - with the related suggestion to connect the vehicle to a charging station - by means of a warning which may comprise , for example , the appearance of a message ( or pop-up ) on the instrument cluster - box PU_DR_NA_PL .

[0051] I f the operational coordinates o f the high-voltage battery belong to the domain AR ( ( SOC, T ) E AR) , the driver' s request is accepted (block 10 ) . Preferably, the acceptance of the driver' s request does not lead to an automatic transition to the driving mode comprising the acceleration from a standing start ( drag-race mode ) ; on the contrary, the system stays in the previous mode ( race mode ) while requesting the driver for the activation o f a launch-control mode LC - assistance to a standing start with maximum acceleration - while simultaneously pressing an accelerator pedal GP and a brake pedal BP . In this condition, the system triggers (block 12 ) the drag-race mode in association with the launch-control mode by switching to the logic value 1 ( TRUE ) of a trigger variable LCTRG. This moreover causes the command of terminating the electrical power supply to the non- propulsive users (further details are provided with reference to Figure 4) . The driver is informed by means of a warning which may comprise, for example, the appearance of a message (or pop-up) on the instrument cluster - box PU_DR_A.

[0052] Once the drag-race mode in association with the launch-control mode has been triggered, preferably a further general check is performed on the parameters of the vehicle, which may lead to a temporary rejection REJ_VC if one or more faults in the vehicle are detected which are incompatible with the forthcoming acceleration maneuvre . If no faults are detected, the driver releases the brake pedal BP (condition BP < BPTHR DR, wherein BPTHRDRis an actuation threshold below which the brake pedal is considered to be released for the purpose of the drag-race maneuvre) and the maneuvre starts. During the maneuvre, a function of managing and controlling the same maneuvre is activated (block 16) and a verification of maneuvre completion is performed cyclically (block 18) . As shown in the diagram of Figure 1, a drag-race maneuvre is considered to be completed (DR_END) when at least one of the following conditions is satisfied: i) Speed v of the vehicle > 230 km / h ii) Time t elapsed from the start of the maneuvre > 10s iii) Distance x covered from the start of the maneuvre > 1 / 4 mi.

[0053] When any of such conditions is verified, the maneuvre is thus considered as completed (DR_END) , and the electrical power supply to the non-propulsive users is restored (block 20) . This corresponds to a partial inhibition of the drag-race mode. If no condition is met, the system remains in the drag-race mode (DR_ON) .

[0054] There follows, block 22, a check on the actuation of the accelerator pedal GP : if it is detected to be lower than a threshold GPTHR DRbelow which the pedal GP is considered to be released for the purpose of the dragrace maneuvre, the drag-race maneuvre is inhibited and the system returns to the previous mode ( race mode ) , going back to the node N .

[0055] I f , on the contrary, the actuation of the pedal GP is found to be higher than the threshold GPTHR DR, then the system remains in the state of partial inhibition of the drag-race mode of block 22 , and the evaluation of the actuation of the pedal GP is repeated at the following iteration . In any case , it is possible to terminate the drag-race mode immediately, with the passage to the node R and the return to block 6A, i f a temperature of the high-voltage battery is detected which exceeds the value of the upper limit temperature curve Tcriticalat the current SOC of the battery .

[0056] Finally, i f the operational coordinates of the high-voltage battery belong to any of the domains CwoPHR, CwoPLR ( ( SOC, T ) G CwoPHR OR CwoPLR) , the driver' s request is put on stand-by, and a thermal preconditioning of the high-voltage battery starts (block 26 ) . The driver is informed by means of a warning which may comprise , for example , the appearance of a message ( or pop-up ) on the instrument cluster - box PU_DR_PC . The vehicle can move , but the maximum discharge power of the battery i s not available yet , and the management of the power is still based on the driving modes which has originated the request for an acceleration maneuvre from a standing start .

[0057] Referring to Figure 4 , the diagrams of the evolution in time shown therein refer to a condition wherein the operational coordinates ( SOC, T ) of the high-voltage battery belong to the activation domain AR . The X axis shows some reference time instants for the evolution of the drag-race maneuvre , speci fically : - instant to = accepting the driver' s request for a drag-race maneuvre (block 10) ,

[0058] - instant ti = enabling the maximum availability of electrical discharge power of the high-voltage battery (block 12) ,

[0059] - instant t2 = releasing the brake pedal BP, instant to = end of the drag-race maneuvre (DR_END) ,

[0060] - instant t4 = releasing the accelerator pedal GP .

[0061] The diagram in Figure 4 shows the following parameters :

[0062] - v = forward speed of the vehicle,

[0063] - Pp ™®Race= electrical power destined to propulsive users (one or more electric motors) during the drag-race maneuvre (i.e. in drag-race mode) ,

[0064] - PHVB™ short-term discharge power of the high- voltage battery,

[0065] - Ppr^pNomRace= maximum electrical power destined to propulsive users (one or more electric motors) in a performance-oriented driving mode, specifically a "race" mode,

[0066] - PeMot=electrical power absorbed by the one or more electric motors,

[0067] - ^Load=electrical power absorbed by non-propulsive electrical users,

[0068] - actuation of the accelerator pedal, reference GP,

[0069] - actuation of the brake pedal, reference BP.

[0070] At the instant t = to the request of the driver is accepted, but the further discharge power ^Psxtra is not available yet. This means that the maximum available discharge power still equals the power of the race mode, i.e. 560 kW in the presently considered example. At the instant t = ti, with LC_TRG = 1, the drag-race mode is triggered (the actuation of the pedals GP and BP is simultaneous and maximum) and the further power becomes immediately available for propulsion, therefore PropRaCe =PHVB"1holds true . The variable LCTRGin the logic state TRUE ( 1 ) reports to the system the driver' s intention to perform the acceleration maneuvre immediately . The logic state of the variable LCTRGmay be used to command the termination of the electrical power supply P oad to the non-propulsive users ( PLoad=0 ) t which generally include the electrical users on the low- voltage network of the vehicle V, i . e . the users supplied by a low-voltage battery . The low-voltage battery shal l therefore perform the supply to the low-voltage thermal conditioning system (valves , pumps and fan / blower ) both of the passenger compartment of the vehicle and of the high-voltage battery, beside having to perform the supply to all the services and to maintain the supply to the control units of the vehicle , without the possibility of being recharged by the high-voltage battery .

[0071] The acceleration begins at the time instant t = t2 . As can be seen in the diagram, at this instant the pedal BP is released ( the actuation falls to 0% ) , while the pedal GP keeps on being actuated at 100% . The electrical power PeMotdelivered to the one or more electric traction motors has a rapid rising edge up to the value PnvBim> which decreases in time since the SOC decreases and the temperature of the high-voltage battery increases . At the instant t = t3the drag-race maneuvre is completed due to one of the above-mentioned conditions i ) - iii ) being met . By way of example , at the instant t = t3the speed of the vehicle amounts to 230 km / h, and therefore the condition i ) is satis fied . Generally speaking, the conditions are formulated so that they can be all satis fied almost simultaneously, so that there are also present a mileage equal to or higher than 1 / 4 mi and a distance t3- t3equal to or higher than 10s . The system switches to the condition DR_END, wherein the latter may also be used to command re-initiating the electrical power supply PLOUCL to the non-propulsive users . At the instant t = ta it is therefore pos sible to notice a new rise of the electrical power PLoadsupplied by the high- voltage battery to the non-propulsive users . At thi s instant , therefore , Pp ™®Race= PHVB"1~ PLOCUI holds true , so that in any case a surplus power is delivered with respect to Ppr^NomRace( i f available , therefore bringing about a condition Pp ™®Race> Ppr“pNomRace) to support an acceleration which is still ongoing beyond 230 km / h . In this sense , a net power cut with return to the maximum value Pp pNomRaceis not a preferred solution during an acceleration maneuvre . Moreover, since the drag-race mode is enabled, the total time to pass from 230 km / h to the maximum speed of the vehicle ( approx . 320 km / h in the presently considered example ) shall be shorter than the time which elapses in the race mode .

[0072] During the acceleration maneuvre , the operational coordinates ( SOC, T ) of the high-voltage battery may exit the activation domain AR, especially i f the driver continues accelerating up to the maximum speed of the vehicle . In this case , the diagram of Figure 1 clearly shows that the drag-race mode is still active , since block 24 can be reached only i f the accelerator pedal GP is released . Of course , the drag-race mode is immediately inhibited i f the curve Tcriticalis exceeded by the temperature of the high-voltage battery at the current SOC, in such a way as to safeguard the battery . In thi s case , it is preferable to cut the power gradually, in order to avoid a sudden complete fall of power during acceleration .

[0073] At the instant t = t4 the accelerator pedal GP is released, which leads to a fall of the speed of the vehicle due to the aerodynamic drag and to a zeroing of the electrical power delivered to the one or more electric traction motors (with a consequent sign reversal , since the motors are operating in the power generation mode ) .

[0074] As further considerations regarding the operating modes described in the foregoing, the following shall be taken into account .

[0075] As regards enabling the maximum availability of power by accessing to the amount PExtra r this might generally be possible already at the block 10 , i . e . as soon as a positive detection is made about the absence of faults , and before the simultaneous pressure of the pedals GP and BP . In embodiments wherein this is implemented, a temporary power increase would be available which would not necessarily depend on the execution of the acceleration maneuvre .

[0076] As regards the termination of the electrical power supply to the non-propulsive users ( and the subsequent restart of the supply) , in addition to the possibility of using the logic state of one or more reference variables ( LCTRGand DR_END in the present case ) , it is possible to use an arbitration strategy of the priorities of distributing the electrical power from the high- voltage battery . An example of such a strategy, proposed by the same Applicant , is described in the Italian Patent Application for Industrial Invention n . 102024000002938 .

[0077] As regards the termination of the electrical power supply to the low-voltage battery, this is an extreme condition, which is preferably chosen only i f the low- voltage battery is fully charged . The condition in itsel f does not preclude the acceleration maneuvre , and i f the low-voltage battery is not completely charged or i f it has a SOC lower than an adj ustable threshold, it is possible to execute the acceleration maneuvre while tolerating a power reduction which may be expressed as PpropRaCe=PHVBm- PDCDC , wherein PDCDC is the electrical power supplied by the high-voltage battery to the low- voltage battery for recharging the latter . It should moreover be noted that the power PDCDC generally amounts to 1-2 kW, and therefore it is a negligible amount with respect to the electrical power PHVB™ , in a way which is substantially independent from the power amount in consideration . It is then possible to conclude that the condition ^P Extra > ^Extra keeps on being satis fied ( PpropRaCe= PnvBm~ PDCDC - PHVBm') •I nthis regard, Figure 5 shows a possible choice of charging (positive ) current and discharging (negative ) current of the low-voltage battery as a function of the respective state of charge LVSOC during the drag-race maneuvre , in particular as a function of a threshold value of the state of charge LVSOC . As mentioned in the foregoing, i f LVSOC < 80% (which, by way of example , is chosen to correspond to the threshold value for LVSOC ) , the low- voltage battery can absorb electrical power from the high-voltage battery also in the case of the termination of the electrical power supply to the ( other ) non- propulsive users , and in particular it can absorb charging current up to the value M corresponding to the current condition, the possibility is rej ected of a simultaneous discharge of the low-voltage battery . I f LVSOC > 80% , the charging of the low-voltage battery is inhibited ( therefore , the termination of electrical power supply from the high-voltage battery to the non-propulsive users also involves the low-voltage battery) and the low-voltage battery supplies all the low-voltage (non-propulsive ) users with a current not higher than -M ^MaxDisch ^the module whereof progressively decreases until reaching zero at LVSOC = 80% . This means that , during the acceleration maneuvre , it is also possible to re-enable charging the low-voltage battery, i f LVSOC falls below 80% . Finally, as regards the management of the thermal conditioning of the passenger compartment and of the thermal conditioning of the high-voltage battery, it i s preferable to limit , until disabling, the conditioning of the passenger compartment only i f the temperature o f the air output from the AC vents is not too distant from the target temperature requested by the driver, and i f there are no pending requests for high-priority conditioning, such as windscreen defrosting or a request for maximum air conditioning power (max AC ) . Similarly, the thermal conditioning of the high-voltage battery - speci fically, the cooling - may be reduced or disabled provided that this does not lead to an interruption of the acceleration maneuvre due to exceeding the limit ^critical • This means that it is preferable to limit , until disabling, the cooling of the high-voltage battery only i f the temperature of the battery at the current SOC i s lower than the value on the limit curve Tcrtticaiat the same SOC by a safety margin

[0078] Thanks to the method according to the invention it is possible to of fer the driver the possibility of executing acceleration maneuvres from a standing start ( drag-race or shorter-duration maneuvres ) with a signi ficantly more satis fying experience with respect to the normal performance-oriented driving modes , and to fully exploit the availability of electrical power of the system .

[0079] Of course , the implementation details and the embodiments may amply vary with respect to what has been described and illustrated herein, without departing from the extent of the present invention, as defined in the annexed claims .

Claims

CLAIMS1 . A method for managing the supply of electrical power from a first battery to one or more traction electric motors of an electric powertrain of a vehicle during an acceleration maneuvre from a standing start , the procedure including :- defining, as a function of a temperature ( T ) of the first battery and a state of charge ( SOC ) of the first battery, a domain of maximum availability of electrical discharge power of said first battery (MPR) , the domain of maximum availability of electrical discharge power of the battery (MPR) being delimited by a lower state of charge limit (SOCMin) , by an upper state of charge limit (SOCMax) , by a first lower limit temperature curve (TLow) and a first upper limit temperature curve ( TCritical) ,- defining a first sub-domain ( CwPHR) and a second sub-domain ( CwoPHR) internal to said domain of maximum availability of battery discharge electrical power (MPR) , the first sub-domain ( CwPHR) being delimited by the first upper limit temperature curve ( TCritical) and a second upper temperature limit curve (TUpBand) , the second upper limit temperature curve (TUpBand) having temperature values lower than the temperature values of said first upper limit temperature curve ( TCritical) , and the second sub-domain ( CwoPHR) being delimited by the second upper limit temperature curve (TUpBand') and a third upper limit temperature curve (THigh) , the third upper limit temperature curve (THigh) having temperature values lower than the temperature values of said second upper limit temperature curve (TUpBand) ,- defining an activation domain (AR) as a domain resulting from a di f ference between said domain of maximum availability of battery discharge electrical power (MPR) of the first battery and said first sub-domain ( CwPHR) and second sub-domain ( CwoPHR) ,- determining, upon receipt of a request from a driver of the vehicle for an acceleration manoeuvre from a standing start , a pair of operational coordinates ( SOC, T ) of the first battery comprising a current state of charge ( SOC ) of said first battery and a current temperature ( T ) of said first battery, determining a location of said operational coordinates with respect to said domain of maximum availability of electrical discharge power of the first battery (MPR) , enabling the acceleration manoeuvre from a standing start and commanding a termination of the supply of electrical power from said first battery to one or more non-propulsive electrical users of the vehicle other than said one or more traction electric motors i f the operational coordinates of the battery are located within the activation domain (AR) ,- reporting a need for thermal conditioning of the first battery without connection to a charging station and initiating thermal conditioning of the first battery i f the operational coordinates of the first battery are within the second sub-domain ( CwoPHR) , and rej ecting the request for the acceleration manoeuvre from a standing start , indicating a need for thermal conditioning of the first battery with connection to a charging station i f the operational coordinates of the first battery are located within the first sub-domain ( CwPHR) .2 . The method of claim 1 in which the said first sub-domain ( CwPHR) and said second sub-domain ( CwoPHR) are further delimited by said lower state of charge limit (SOCMin) and by said upper state of charge limit (SOCMax) .

3. The method of any of claims 1 , 2 , further including defining a first extra-domain ( CwoPLR) and asecond extra-domain ( CwPLR) external to said domain of maximum availability of electrical discharge power of the first battery (MPR) , the first extra-domain ( CwoPLR) being delimited by the first lower limit temperature curve ( TLOW) and a second lower limit temperature curve ( TL0Band ') r the second lower limit temperature curve ^LoBand ') having temperature values lower than the temperature values of said first lower limit temperature curve ( TLOW) , and the second extra-domain ( CwPLR) being delimited by said second lower limit temperature curve ^LoBand ^ and having temperature values lower than those of said second lower limit temperature curve TL0Band / wherein the method includes :- reporting a need for thermal conditioning of the first battery without connection to a charging station, and initiating thermal conditioning of the first battery i f the operational coordinates of the first battery are within the first extra-domain ( CwoPLR) , and rej ecting the request for the acceleration manoeuvre from a standing start , indicating a need for thermal conditioning of the first battery with connection to a charging station i f the operational coordinates of the first battery are located within the second extra-domain ( CwPLR) , wherein, i f the operational coordinates of the battery are located within the first extra-domain ( CwoPLR) or within the second sub-domain ( CwoPHR) , the method further includes enabling the acceleration manoeuvre from a standing start , with availability of electrical discharge power of the first battery lower than the maximum availability of electrical discharge power of the first battery .4 . The method of claim 3 , wherein said first extradomain ( CwoPLR) and second extra-domain ( CwPLR) are further delimited by said lower state of charge limit(SOCMin) and by said upper state of charge limit (SOCMax) .

5. The method of claim 1 or claim 2 , wherein the need for thermal conditioning of the first battery when the operating coordinates of the first battery are in the first sub-domain ( CwPHR) or in the second sub-domain ( CwoPHR) includes a cooling of the first battery .

6. The method of claim 3 or claim 4 , where the need for thermal conditioning of the f irst battery when the operational coordinates of the first battery are in the first extra-domain ( CwoPLR) or the second extra-domain ( CwPLR) includes a heating of the first battery .7 . The method of any of the preceding claims , further including defining a third extra-domain ( CwPLeR) delimited superiorly by said lower state of charge limit (SOCMin) regardless of the temperature of the first battery, the method including rej ecting the request for the acceleration manoeuvre from a standing start by reporting a need for connection to a charging station i f the operational coordinates of the first battery are located within the third extra-domain ( CwPLeR) .

8. The method of any of the preceding claims , wherein the said lower state of charge limit (SOCMin) is 80% , wherein the said upper state of charge limit (SOCMax) is 100% , and wherein said first upper limit temperature curve Tcritica ) is a curve at constant temperature values and equal to a critical temperature of said first battery, in particular 55 ° C .

9. The method of any of the preceding claims , wherein said one or more non-propulsive electrical users include a thermal conditioning unit of said first battery and a thermal conditioning unit of a vehicle cabin, and wherein said commanding a termination of the supply of electrical power from said first battery to one or more non-propulsive electrical users of the vehicle includes the termination of an electrical supply of said thermalconditioning unit of said first battery and said thermal conditioning unit of the vehicle cabin .10 . The method of claim 9 , wherein said non propulsive users further include a DCDC converter and a further battery, said further battery having a voltage lower than that first battery, being configured to supply non-propulsive users of the vehicle , and being configured to be recharged by said first battery, wherein said commanding a termination of the supply of electrical power from said first battery to one or more non- propulsive electrical users of the vehicle includes maintaining an electrical power supply from said first battery to said further battery by preventing discharge thereof i f a state of charge ( LVSOC ) of the further battery is below a threshold value , particularly 80% , and terminating the supply of the further battery by preventing the recharge thereof by said first battery i f a state of charge ( LVSOC ) of the further battery is above said threshold value , particularly 80% .

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