LEAKAGE CURRENT MONITORING DURING MODE 4 CHARGING OF A VEHICLE BATTERY

Abstract

A monitoring method is implemented in a vehicle comprising a rechargeable main battery and coupled to a charging connector capable of being temporarily coupled to a power source to receive a charging current having an indicated informative value and to supply the main battery during a charging in mode 4. This method comprises a step (10-30) in which, during a charging in mode 4, a deviation value representative of a difference between this informative value and a measurement of a current flowing between the terminals of the main battery is compared to a chosen threshold, and, when this deviation value is greater than the threshold, the power source is ordered to stop supplying the charging current. Figure 3

Description

Title of the invention: LEAKAGE CURRENT MONITORING DURING MODE 4 CHARGING OF A VEHICLE BATTERY Technical field of the invention

[0001] The invention relates to vehicles comprising a battery rechargeable in mode 4 by an external power source, and more precisely to the monitoring within such vehicles of the recharging phases in mode 4. State of the art

[0002] Certain vehicles, possibly of the automobile type, comprise a so-called "main" (or traction) battery coupled to a charging connector which is suitable, during charging in mode 4, for being temporarily coupled to a power source via a charging cable (generally fixedly attached to the latter).

[0003] Here, the term "main (or traction) battery" means a battery responsible for supplying electric current to an on-board network via a converter and an electric motor forming part of the powertrain (or GMP) of its vehicle.

[0004] Furthermore, it is recalled that in a recharge in mode 4, the main battery (to be recharged) is supplied directly with high direct current (typically between 100 A and 400 A) at a low input voltage (typically 450 V) by the power source (via the recharge connector), i.e. without conversion by a current converter of the vehicle.

[0005] In a vehicle such as those presented above, once the charging connector is correctly coupled to the power source, a computer of the vehicle transmits to the power source, via the charging connector, information defining the maximum charging current, then the power source provides the charging connector with a continuous charging current which is at most equal to the maximum charging current, and this current flows to the terminals of the main battery in order to recharge it.

[0006] Currently, during a mode 4 recharge, monitoring the good electrical insulation of the power source - vehicle assembly is the responsibility of the power source. But the effectiveness of this monitoring varies from one power source manufacturer to another. Consequently, it may happen that a short circuit (or similar) occurs at the power source or its charging cable, which may, for example, cause a leakage current which could cause a fire in the power source or the charging cable which may then spread to the vehicle via its charging connector. For example, abnormal oxidation of a screw securing the connection gun of a charging cable can cause such a short circuit.

[0007] The invention therefore aims in particular to detect a leakage current during a mode 4 recharging phase of a main battery of a vehicle. Presentation of the invention

[0008] For this purpose, it proposes in particular a monitoring method intended to be implemented in a vehicle comprising a rechargeable main battery and coupled to a charging connector capable of being temporarily coupled to a power source to receive a charging current having an indicated informative value and intended to supply the main battery during charging in mode 4.

[0009] This monitoring method is characterized by the fact that it comprises a step in which, during a recharge in mode 4, a deviation value representative of a difference between the indicated informative value and a measurement of a current flowing between terminals of the main battery is compared with a chosen threshold, and, when this deviation value is greater than this threshold, the power source is ordered to stop supplying the recharge current.

[0010] Thanks to the invention, a leakage current can be detected at any time during a recharge in mode 4, which makes it possible to avoid, in particular, a fire at the power source and / or the vehicle.

[0011] The monitoring method according to the invention may include other characteristics which may be taken separately or in combination, and in particular:

[0012] - in its step the power source can be ordered to stop supplying the recharge current when the deviation value is greater than the threshold for a chosen duration;

[0013] - in the presence of the first option, in its step the chosen duration can be between 50 ms and 1 s;

[0014] - in its step we can determine the absolute value of the difference between the value informative and the measurement of the current flowing between the terminals of the main battery, then we can determine the difference value by dividing by the informative value a result of a multiplication of this absolute value determined by one hundred;

[0015] - in the presence of the last option, in its step the threshold can be a percentage between 3% and 20%. For example, this threshold can be equal to 5%;

[0016] - in its step, when the deviation value is greater than the threshold, we can decouple the main battery from the charging connector.

[0017] The invention also provides a computer program product comprising a set of instructions which, when executed by processing means, is capable of implement a monitoring method of the type presented above to monitor a mode 4 charging phase of a main battery equipping a vehicle, rechargeable and coupled to a vehicle charging connector suitable for being temporarily coupled to a power source.

[0018] The invention also proposes a monitoring device intended to equip a vehicle comprising a rechargeable main battery and coupled to a charging connector capable of being temporarily coupled to a power source to receive a charging current having an indicated informative value and intended to supply the main battery during charging in mode 4.

[0019] This monitoring device is characterized by the fact that it comprises at least one processor and at least one memory arranged to carry out the operations consisting, during a recharge in mode 4, in comparing with a chosen threshold a deviation value representative of a difference between the informative value and a measurement of a current flowing between terminals of the main battery, and, when this deviation value is greater than this threshold, in triggering a cessation of supply of the recharge current by the power source.

[0020] The invention also provides a vehicle, possibly of the automobile type, and comprising:

[0021] - a main rechargeable battery coupled to a charging connector specific to be temporarily coupled to a power source to receive a charging current having an indicated informational value and to supply the main battery during a mode 4 recharge, and

[0022] - a monitoring device of the type presented above. Brief description of the figures

[0023] Other characteristics and advantages of the invention will appear on examining the detailed description below, and the appended drawings, in which:

[0024] [Fig. 1] schematically and functionally illustrates an exemplary embodiment of a vehicle comprising a GMP, with an electric motor powered by a main battery rechargeable in mode 4 via a charging connector temporarily coupled to a power source, and a monitoring device according to the invention,

[0025] [Fig.2] schematically and functionally illustrates an exemplary embodiment of a vehicle charger comprising a converter and a charging computer comprising a monitoring device according to the invention, and

[0026] [Fig.3] schematically illustrates an example of an algorithm implementing a monitoring method according to the invention. Detailed description of the invention

[0027] The invention aims in particular to propose a monitoring method, and an associated monitoring device DS, intended to enable the monitoring of the recharging phases in mode 4 of a main battery BP of a vehicle V.

[0028] In the following, it is considered, by way of non-limiting example, that the vehicle V is of the automobile type. It is for example a car, as illustrated in [Fig.l]. But the invention is not limited to this type of vehicle. It relates in fact to any type of vehicle comprising a main battery rechargeable at least in mode 4. Thus, it relates, for example, to land vehicles (utility vehicles, camper vans, minibuses, coaches, trucks, motorcycles, road machinery, construction machinery, agricultural machinery, leisure machinery (snowmobile, kart), and tracked vehicles, for example), boats and aircraft.

[0029] Furthermore, it is considered in the following, by way of non-limiting example, that the vehicle V comprises a powertrain (or GMP) of the all-electric type (and therefore whose drive is provided exclusively by at least one electric motor MME). But the GMP could be of the hybrid type (thermal and electric).

[0030] [Fig.l] schematically shows a vehicle V comprising an electric GMP transmission chain, an on-board network RB, a service battery BS, a main (or traction) battery BP, a converter CV, a charging connector CN (here temporarily coupled to a power source SA), and a monitoring device DS according to the invention.

[0031] The on-board network RB is an electrical power supply network to which electrical (or electronic) equipment (or components) that consume electrical energy are coupled.

[0032] The service battery BS is responsible for supplying electrical energy to the on-board network RB, in addition to that supplied by the CV converter powered by the main battery BP, and sometimes instead of this CV converter. For example, this service battery BS can be arranged in the form of a very low voltage type battery (typically 12 V, 24 V or 48 V). It is rechargeable at least by the CV current converter. It is considered in the following, by way of non-limiting example, that the service battery BS is of the 12 V Lithium-ion type.

[0033] The transmission chain has a GMP which is, here, purely electric and therefore which comprises, in particular, an electric motor MME, a motor shaft AM, and a transmission shaft AT. Here, the term “electric motor” means an electric machine arranged so as to provide or recover torque to move the vehicle V.

[0034] The operation of the GMP is supervised by a CS supervision computer.

[0035] The electric motor MME (here an electric motor) is coupled to the main battery BP, in order to be supplied with electrical energy, as well that possibly supply this main BP battery with electrical energy, particularly during regenerative braking.

[0036] Furthermore, this electric motor MME is coupled to the motor shaft AM, to provide it with torque by rotational drive. This motor shaft AM is here coupled to a reducer RD which is also coupled to the transmission shaft AT, itself coupled to a first train T1 (here of wheels), preferably via a differential D1.

[0037] This first train T1 is here located in the front part PVV of the vehicle V. But in a variant this first train T1 could be the one which is here referenced T2 and which is located in the rear part PRV of the vehicle V.

[0038] The CV converter is also responsible during the driving phases of the vehicle V for converting part of the electric current stored in the main battery BP to supply converted electric current, on the one hand, to the on-board network RB, and, on the other hand, to the service battery BS (to recharge it).

[0039] It will be noted, as illustrated non-limitingly in [Fig.l], that the CV converter can be part of a CH charger also comprising a CC recharge calculator responsible, at least, for controlling the recharge of the main battery BP, in particular in mode 4.

[0040] It is recalled that in a recharge in mode 4, the main battery BP is supplied directly with high direct current (typically between 100 A and 400 A) under a low input voltage (typically 450 V) by the power source SA which is temporarily coupled to the recharge connector CN of the vehicle V via a recharge cable CR. In this mode 4 there is therefore no conversion by the converter CV of the recharge current which is supplied by the power source SA, unlike what happens in a mode 2 or 3.

[0041] The main (or traction) battery BP may, for example, comprise electrical energy storage cells, possibly electrochemical (for example of the lithium-ion (or Li-ion) or Ni-Mh or Ni-Cd type). Also for example, the main battery BP may be of the low voltage type (typically 450 V for illustration purposes). But it could be of the medium voltage or high voltage type.

[0042] It will be noted that in the example illustrated non-limitingly in [Fig.l] the main battery BP is suitable not only for recharges in mode 4, but also for recharges in mode 2 or 3, under the control of the CC recharge calculator associated with the CV converter. But the main battery BP could only be suitable for recharges in mode 4.

[0043] It will also be noted that the main battery BP is associated with a battery box BB which notably comprises a battery calculator CB, an isolation device DI, and voltage / current measuring means (not illustrated). This main battery BP and its battery box BB constitute a battery pack.

[0044] The isolation device DI is arranged so as to isolate, if necessary, the main battery BP from the charging connector CN and / or from the converter CV and / or from the electric motor MME. For example, this isolation device DI may comprise contactors (or switches), possibly based on MOSFET(s) and each capable of taking an open (or non-conducting) state and a closed (or conducting) state. It is therefore interposed between the charging connector CN and the main battery BP, between the main battery BP and the converter CV, between the main battery BP and the electric motor MME, between the converter CV and the electric motor MME, and between the charging connector CN and the electric motor MME, as illustrated non-limitingly in [Fig.2].

[0045] It will also be noted that in the example illustrated non-limitingly in [Fig. 1] the vehicle V also comprises a distribution box BD to which the service battery BS, the converter CV and the on-board network RB are coupled. This distribution box BD is responsible for distributing in the on-board network RB the electrical energy stored in the service battery BS or produced by the converter CV, for the supply of the electrical components (or equipment) coupled to the on-board network RB according to power supply requests received (in particular from the supervision computer CS of the GMP).

[0046] As mentioned above, the invention proposes in particular a monitoring method intended to enable monitoring of the recharging phases in mode 4 of the main battery BP, and therefore when the recharging connector CN is temporarily coupled to a power source SA via a recharging cable CR.

[0047] This (control) method can be implemented at least partially by the monitoring device DS (illustrated in FIGS. 1 and 2) which comprises for this purpose at least one processor PR1, for example a digital signal processor (or DSP), and at least one memory MD. This monitoring device DS can therefore be implemented in the form of a combination of electrical or electronic circuits or components (or "hardware") and software modules (or "software"). For example, it can be a microcontroller.

[0048] The memory MD is live in order to store instructions for the implementation by the processor PR1 of at least part of the monitoring method. The processor PR1 may comprise integrated (or printed) circuits, or several integrated (or printed) circuits connected by wired or wireless connections. An integrated (or printed) circuit is understood to mean any type of device capable of carrying out at least one electrical or electronic operation.

[0049] In the example illustrated non-limitingly in Figures 1 and 2, the monitoring device DS is part of the charging computer CC (and therefore of the charger CH). But this is not obligatory. Indeed, the monitoring device DS could include its own dedicated calculator, which is then coupled to the DC charging calculator, or could be part of another on-board calculator, such as the CB battery calculator.

[0050] As illustrated non-limitingly in [Fig.3], the (monitoring) method, according to the invention, comprises a step 10-30 which is implemented in each recharging phase in mode 4.

[0051] It is recalled that once the charging connector CN has been correctly coupled to a power source SA (via a charging cable CR), a computer of the vehicle V transmits to this power source SA, via the charging connector CN and the charging cable CR, an information icrm which defines the maximum charging current crm that the battery computer CB has determined for its main battery BP taking into account its current state. For example, this computer can be the charging computer CC of the charger CH, which then receives this information icrm from the battery computer CB. Then, the power source SA transmits to this computer (here CC), still via the charging cable CR and the charging connector CN, an informative value vi which indicates the charging current ers which it will immediately supply and which is at most equal to the maximum charging current crm.In the absence of a problem with the power source SA and the charging cable CR, the charging connector CN receives this charging current ers which then flows to the terminals of the main battery BP, after passing through a sub-part of the isolation device DI, in order to recharge it.

[0052] Step 10-30 of the method comprises a sub-step 20 in which one (the monitoring device DS) compares to a chosen threshold si a deviation value ve which is representative of the difference between the informative value vi (transmitted by the power source SA) and a measurement me of the current which flows between the terminals (positive and negative) of the main battery BP.

[0053] For example, step 10-30 of the method may comprise a sub-step 10 in which one (the monitoring device DS) begins by determining the difference between the informative value vi and the current measurement me which is provided by a measuring device DM coupled to the terminals of the main battery BP (i.e. vi - me). It will be noted that in the example illustrated non-limitingly in [Fig.2] the measuring device DM is external to the main battery BP. But in an alternative embodiment (not illustrated) the measuring device DM could be part of the main battery BP.

[0054] When the deviation value ve is greater than the threshold si (i.e. ve > si), the monitoring device DS orders the power source SA to stop supplying the recharge current ers in a sub-step 30 of step 10-30. It will be understood that when the condition ve > si is met, the recharge current me which supplies the The main battery BP differs significantly (or even notably) from the charging current ers which is supplied by the power source SA and therefore there is definitely a leakage current, a priori at the level of the power source SA or the charging cable CR. Consequently, for safety reasons (in particular to avoid a fire at the level of the power source SA and / or the vehicle V) it is necessary to interrupt charging immediately (in advance).

[0055] It will be noted that it is the monitoring device DS which triggers in sub-step 30 the cessation of supply of the recharge current ers by the power source SA thanks to the operations carried out by its processor PR1 and memory MD.

[0056] It will also be noted that the monitoring device DS generates an order (or message) to interrupt the charging which is transmitted to the power source SA, via the charging connector CN and the charging cable CR, (here) by the charging computer CC of the charger CH.

[0057] It will be understood that when the deviation value ve is less than or equal to the threshold si (i.e. ve < si), we (the monitoring device DS) know that the recharge is taking place normally (and therefore that there is no leakage current), and therefore we return to carry out sub-step 10 with a new current measurement me.

[0058] Preferably, to avoid deciding on a cessation of the supply of the recharging current ers (or an early interruption of the recharging), for example due to an error in the measurement of the current me by the measuring device DM or a sudden non-significant variation in the measurement of the current me, the monitoring device DS only decides on this cessation, in sub-step 30, on condition that the deviation value ve remains greater than the threshold si for a chosen duration dl.

[0059] If the deviation value ve remains greater than the threshold if for a duration which is strictly less than the chosen duration dl, we (the monitoring device DS) consider that the recharge is taking place normally (and therefore that there is no leakage current), and therefore we return to carry out sub-step 10 with a new current measurement me.

[0060] In order to implement this last option, one (the monitoring device DS) can trigger a time delay having the chosen duration dl as soon as the deviation value ve becomes for the first time greater than the threshold si, and when this time delay expires (and one still has ve > si, without interruption), one (the monitoring device DS) decides on the early interruption of the recharge.

[0061] For example, in sub-step 30 of step 10-30, the duration dl chosen may be between 50 ms and 1 s. As an illustrative example, the duration dl may be equal to 300 ms. But other values ​​of duration dl may be used. For example, the value of the duration dl may be chosen during the development phase of the vehicle V.

[0062] Also for example, in sub-step 10 of step 10-30, one (the monitoring device DS) can determine the absolute value va of the difference between the informative value vi and the measurement me of the current flowing between the terminals of the main battery BP (i.e. va = Ivi - mcl). Then, one (the monitoring device DS) can determine the deviation value ve by dividing by the informative value vi the result of multiplying the absolute value va determined by one hundred (i.e. ve = (va*100) / vi = (Ivi - mcl*100) / vi). In this case the deviation value ve corresponds to a percentage of current loss.

[0063] For example, in the presence of the last option in sub-step 20 of step 10-30, the threshold si chosen may be a percentage which is between 3% and 20%. As an illustrative example, the threshold si may be equal to 5%. But other threshold si values ​​may be used. For example, the threshold si value may be chosen during the vehicle V development phase.

[0064] But in an alternative embodiment the deviation value ve could be equal to the absolute value va, for example.

[0065] It will be noted that in sub-step 30 of step 10-30, when the deviation value ve is greater than the threshold si (i.e. ve > si), it is also possible to decouple (the monitoring device DS can also trigger a decoupling of) the main battery BP from the charging connector CN. This option is intended to secure the main battery BP by preventing a fire from spreading to it.

[0066] For example, the isolation of the main battery BP from the charging connector CN can be done via the isolation device DI. To do this, it is possible, for example, to place at least one contactor (or switch) of the isolation device DI in its open state.

[0067] It will also be noted that in sub-step 30 it is possible to alert a (the monitoring device DS can trigger the alert of a) user of the vehicle V, for example by means of an illuminated indicator light and / or a message (preferably dedicated to the interruption of charging) which is displayed on at least one screen of the vehicle V (for example the dashboard or a central instrument panel) or on the screen of a smartphone of the user, and / or broadcast by at least one loudspeaker of the vehicle V or of this smartphone. Thus, the user is informed of the problem encountered and can, for example, decide to change the power source to carry out a new recharge.

[0068] It will also be noted that in sub-step 30 it is also possible to record (the monitoring device DS can also possibly trigger the recording) in at least one memory of the vehicle V at least one fault code which is representative of an early interruption of recharging.

[0069] Recording each fault code is useful to after-sales service personnel. sale which supports the vehicle V to inform the user of the latter (V) of a problem of early interruption of recharging resulting from a leakage current detected during recharging by a power source SA which it used.

[0070] It will also be noted that in sub-step 30, when the vehicle V has a navigation function capable of determining its current geographical position, the geographical position of the vehicle V can also be recorded with each fault code. Thus, in an after-sales service, the user of the vehicle V can also be informed of the location where the leakage current problem was detected so that he can determine the power source SA causing this problem. The after-sales service can also inform the manager of the power source SA where the leakage current problem was detected.

[0071] For example, the authorization to carry out a new recharge can be restored when the recharge computer CC or the battery computer CB detects that the recharge cable CR is no longer connected to the recharge connector CN of the vehicle V. A new recharge can then be attempted by the user of the vehicle V on the same power source SA or on another power source (after a new connection to the recharge connector CN), with a new implementation of the leakage current monitoring method.

[0072] It will also be noted, as illustrated non-limitingly in [Fig. 2], that the charging computer CC (or the dedicated computer of the monitoring device DS) may also comprise a mass memory MM1, in particular for the temporary storage of the current measurements me and any intermediate data involved in all its calculations and processing. Furthermore, this charging computer CC (or the dedicated computer of the monitoring device DS) may also comprise an input interface IE for receiving at least the current measurements me to use them in calculations or processing, possibly after having formatted and / or demodulated and / or amplified them, in a manner known per se, by means of a digital signal processor PR2.In addition, this CC charging calculator (or the dedicated calculator of the DS monitoring device) can also include an IS output interface, in particular to deliver orders to interrupt charging in mode 4, decoupling orders between the main battery BP and the CN charging connector (opening of contactor(s) (or switch(es)) of the DI isolation device), or messages containing a fault code (with a possible geographical position of the SA power source), or user alert messages.

[0073] It will also be noted that the invention also proposes a computer program product (or computer program) comprising a set of instructions which, when executed by processing means of the electronic circuit (or hardware) type, such as for example the processor PR1, is capable of implementing the monitoring method described above for monitoring the charging phases in mode 4 of the main battery BP of the vehicle V.

Claims

Claims

1. Monitoring method for a vehicle (V) comprising a rechargeable main battery (BP) coupled to a charging connector (CN) capable of being temporarily coupled to a power source (SA) to receive a charging current having an indicated informative value and to supply said main battery (BP) during a recharge in mode 4, characterized in that it comprises a step (10-30) in which, during a recharge in mode 4, a deviation value representative of a difference between said informative value and a measurement of a current flowing between terminals of said main battery (BP) is compared with a chosen threshold, and, when said deviation value is greater than said threshold, said power source (SA) is ordered to stop supplying said charging current.

2. Method according to claim 1, characterized in that in said step (10-30) said power source (SA) is ordered to stop supplying said recharge current when said deviation value is greater than said threshold for a chosen duration.

3. Method according to claim 2, characterized in that in said step (10-30) said chosen duration is between 50 ms and 1 s.

4. Method according to one of claims 1 to 3, characterized in that in said step (10-30) the absolute value of said difference between said informative value and said measurement of the current flowing between the terminals of said main battery (BP) is determined, then said difference value is determined by dividing by said informative value a result of a multiplication of said determined absolute value by one hundred.

5. Method according to claim 4, characterized in that in said step (10-30) said threshold is a percentage between 3% and 20%.

6. Method according to claim 5, characterized in that in said step (10-30) said threshold is equal to 5%.

7. Method according to one of claims 1 to 6, characterized in that in said step (10-30), when said deviation value is greater than said threshold, said main battery (BP) is decoupled from said charging connector (CN).

8. Computer program product comprising a set of instructions which, when executed by processing means, is capable of implementing the monitoring method according to one of claims 1 to 7 for monitoring a mode 4 recharging phase of a battery main battery (BP) equipping a vehicle (V), rechargeable and coupled to a charging connector (CN) of said vehicle (V) capable of being temporarily coupled to a power source (SA).

9. Monitoring device (DS) for a vehicle (V) comprising a rechargeable main battery (BP) coupled to a charging connector (CN) capable of being temporarily coupled to a power source (SA) to receive a charging current having an indicated informative value and to supply said main battery (BP) during a recharge in mode 4, characterized in that it comprises at least one processor (PR1) and at least one memory (MD) arranged to carry out the operations consisting, during a recharge in mode 4, in comparing with a chosen threshold a deviation value representative of a difference between said informative value and a measurement of a current flowing between terminals of said main battery (BP), and, when said deviation value is greater than said threshold, in triggering a cessation of supply of said charging current by said power source (SA).

10. Vehicle (V) comprising a rechargeable main battery (BP) coupled to a charging connector (CN) capable of being temporarily coupled to a power source (SA) to receive a charging current having an indicated informative value and to supply said main battery (BP) during charging in mode 4, characterized in that it further comprises a monitoring device (DS) according to claim 9.

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