WO2023152428A1

WO2023152428A1 - Leakage current monitoring during mode 4 charging of a vehicle battery

Info

Publication number: WO2023152428A1
Application number: PCT/FR2022/052368
Authority: WO
Inventors: Olivier BALENGHIEN; Arnaud De Croutte; Alexandre Morel; Marc POTIER
Original assignee: Psa Automobiles Sa
Priority date: 2022-02-11
Filing date: 2022-12-15
Publication date: 2023-08-17
Also published as: FR3132801A1

Abstract

The invention relates to a monitoring method implemented in a vehicle comprising a rechargeable main battery and coupled to a charging connector able to be temporarily coupled to a power source to receive a charging current having an indicated information value and which must supply the main battery during mode 4 charging. This method comprises a step (10-30) in which, during mode 4 charging, a deviation value representative of a difference between this information value and a measurement of a current flowing between the terminals of the main battery is compared with a chosen threshold and, when this deviation value is greater than the threshold, the power source is instructed to stop supplying the charging current.

Description

DESCRIPTION

TITLE: LEAKAGE CURRENT MONITORING DURING MODE 4 CHARGING OF A VEHICLE BATTERY

The present invention claims the priority of French application No. 2201200 filed on February 11, 2022, the content of which (text, drawings and claims) is incorporated herein by reference.

Technical field of the invention

The invention relates to vehicles comprising a battery rechargeable in mode 4 by an external power source, and more specifically the monitoring within such vehicles of the charging phases in mode 4.

State of the art

Some vehicles, possibly of the automotive type, include a so-called "main" (or traction) battery coupled to a charging connector which is capable, during charging in mode 4, of being temporarily coupled to a power source via a charging cable (usually fixed to the latter).

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 machine forming part of the powertrain (or GMP) of its vehicle.

Furthermore, it is recalled that in a mode 4 recharge, the main battery (to be recharged) 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 (via the charging connector), i.e. without conversion by a vehicle power converter.

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

Currently, when charging in mode 4, monitoring the correct 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. Therefore, it may happen that a short circuit (or the like) occurs in the power source or its charging cable, which may, for example, cause a leakage current which may be the cause a fire in the power source or the charging cable which can then spread to the vehicle via its charging connector. For example, abnormal oxidation of a fixing screw of the charging cable connection gun can be the cause of such a short circuit.

The object of the invention is therefore in particular to detect a leakage current during a charging phase in mode 4 of a main battery of a vehicle.

Presentation of the invention

In particular, it proposes for this purpose 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 in order to receive a charging current having a informative value indicated and intended to supply the main battery during a recharge in mode 4.

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

Thanks to the invention, it is possible to detect a leakage current 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 vehicle level.

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

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

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

- in its step, we can determine the absolute value of the difference between the informative value 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 determined absolute value by one hundred;

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

- in its step, when the deviation value is greater than the threshold, the main battery can be decoupled from the charging connector.

The invention also proposes a computer program product comprising a set of instructions which, when it is executed by processing means, is capable of implementing a monitoring method of the type presented above for monitoring a mode 4 recharging phase of a main battery fitted to a vehicle, rechargeable and coupled to a vehicle recharging connector capable of being temporarily coupled to a power source.

The invention also proposes a monitoring device intended to equip a vehicle comprising a rechargeable main battery and coupled to a recharging connector able to be temporarily coupled to a power source in order to receive a recharging current having an indicated informative value and before power the main battery when charging in mode 4.

This monitoring device is characterized in that it comprises at least a 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 difference value representative of a difference between the informative value and a measurement of a current flowing between of the terminals of the main battery, and, when this difference value is greater than this threshold, in triggering a cessation of supply of the charging current by the power source.

The invention also proposes a vehicle, optionally of the automobile type, and comprising:

- a rechargeable main battery coupled to a charging connector able to be temporarily coupled to a power source to receive a charging current having an indicated informative value and to supply the main battery during charging in mode 4, and

- A monitoring device of the type presented above.

Brief description of figures

Other characteristics and advantages of the invention will appear on examination of the detailed description below, and of the appended drawings, in which:

[Fig. 1] schematically and functionally illustrates an exemplary embodiment of a vehicle comprising a GMP, with an electric drive machine 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,

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

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

Detailed description of the invention

The object of the invention is in particular to propose a monitoring method, and an associated monitoring device DS, intended to allow the monitoring charging phases in mode 4 of a main battery BP of a vehicle V.

In what follows, it is considered, by way of non-limiting example, that the vehicle V is of the automobile type. This is for example a car, as shown in Figure 1. But the invention is not limited to this type of vehicle. It relates in fact to any type of vehicle comprising a rechargeable main battery at least in mode 4. Thus, it relates, for example, to land vehicles (utility vehicles, camper vans, minibuses, coaches, trucks, motorcycles, road construction machinery, construction machinery, agricultural machinery, recreational machinery (snowmobile, go-kart), and caterpillar machinery, for example), boats and aircraft.

Furthermore, it is considered in what follows, by way of non-limiting example, that the vehicle V comprises a powertrain (or GMP) of the all-electric type (and therefore whose traction is ensured exclusively by at least one electric motor machine MRS). But the GMP could be of the hybrid type (thermal and electric).

Schematically shown in Figure 1 is 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.

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.

The service battery BS is responsible for supplying electric power to the on-board network RB, in addition to that supplied by the converter CV powered by the main battery BP, and sometimes instead of this converter CV. For example, this service battery BS can be arranged in the form of a battery of the very low voltage type (typically 12 V, 24 V or 48 V). It is rechargeable at least by the current converter CV. It is considered in what follows, by way of non-limiting example, that the service battery BS is of the 12 V Lithium-ion type. The transmission chain has a GMP which is, here, purely electrical and therefore which comprises, in particular, an electric drive machine MME, a motor shaft AM, and a transmission shaft AT. Here, the term "electric motor machine" means an electric machine arranged so as to supply or recover torque to move the vehicle V.

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

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

Furthermore, this electric drive machine 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.

This first train T1 is here located in the front part PW of the vehicle V. But in a variant this first train T 1 could be the one which is here referenced T2 and which is located in the rear part PRV of the vehicle V.

The converter CV 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, the service battery BS (to recharge it).

It will be noted, as illustrated without limitation in FIG. 1, that the converter CV can be part of a charger CH also comprising a charging computer CC responsible, at least, for controlling the charging of the main battery BP, in particular in mode 4 .

It is recalled that in a mode 4 recharge, 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 charging connector V vehicle CN via CR charging cable. 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, contrary to what happens in a mode 2 or 3.

The main (or traction) battery BP can, 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 can be of the low voltage type (typically 450 V by way of illustration). But it could be medium voltage or high voltage.

It will be noted that in the example illustrated without limitation in FIG. 1, the main battery BP is suitable not only for recharging in mode 4, but also for recharging in mode 2 or 3, under the control of the recharging computer CC associated with the converter CV . But the main BP battery might only be suitable for charging in mode 4.

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

The isolation device DI is arranged in such a way as to isolate the main battery BP from the charging connector CN and/or from the converter CV and/or from the electric motor MME if necessary. For example, this DI isolation device may include contactors (or switches), possibly based on MOSFET(s) and each of which can assume an open (or off) state and a closed (or on) state. It is therefore inserted 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 driving machine MME, between the converter CV and the electric driving machine MME, and between the charging connector CN and the electric drive machine MME, as illustrated without limitation in Figure 2.

It will also be noted that in the example illustrated without limitation in FIG. 1, the vehicle V also comprises a distribution box BD to which are coupled the service battery BS, the converter CV and the on-board network RB. 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 supplying the electrical components (or equipment) coupled to the on-board network RB according to power supply requests received (notably from the GMP CS supervision computer).

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

This method (of control) 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 of digital signal (or DSP (“ Digital Signal Processor”)), and at least one MD memory. This monitoring device DS can therefore be produced in the form of a combination of electrical or electronic circuits or components (or “hardware”) and software modules (or “software”). By way of example, it may be a microcontroller.

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 can comprise integrated (or printed) circuits, or else several integrated (or printed) circuits connected by wired or wireless connections. By integrated (or printed) circuit is meant any type of device capable of performing at least one electrical or electronic operation.

In the example illustrated without limitation in FIGS. 1 and 2, the monitoring device DS forms part of the charging computer CC (and therefore of the charger CH). But this is not mandatory. Indeed, the monitoring device DS could include its own dedicated computer, which is then coupled to the charging computer CC, or could be part of another on-board computer, such as for example the battery computer CB.

As illustrated without limitation in FIG. 3, the (monitoring) method, according to the invention, comprises a step 10-30 which is implemented in each phase of recharging in mode 4.

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 connector charging cable CN and the charging cable CR, 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 that it will immediately supply and which is at most equal to the maximum recharge current crm. If there is no 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 crossing a sub-part of the DI isolation device, in order to recharge it.

Step 10-30 of the method comprises a sub-step 20 in which one (the monitoring device DS) compares with a chosen threshold s1 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 flowing between the terminals (positive and negative) of the main battery BP.

For example, step 10-30 of the method can 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 supplied by a device 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 without limitation in FIG. 2, the measuring device DM is external to the main battery BP. But in a variant embodiment (not shown) the measuring device DM could be part of the main battery BP.

When the deviation value ve is greater than the threshold s1 (i.e. ve > s1 ), on (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 > s1 is met, the recharge current me which supplies the main battery BP differs substantially (even notably) from the recharge current ers which is supplied by the power source SA and therefore there are a leakage current, a priori at the level of the power source SA or the charging cable CR. Consequently, for a question of safety (in particular to avoid a fire at the level of the power source SA and/or of the vehicle V) the recharging must be interrupted immediately (in advance).

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

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

It will be understood that when the difference value ve is less than or equal to the threshold s1 (i.e. ve < s1 ), we (the monitoring device DS) know that the recharging is taking place normally (and therefore that there is no leakage current), and therefore we return to perform sub-step 10 with a new current measurement me.

Preferably, to avoid deciding on a cessation of the supply of the charging current ers (or an early interruption of the charging), for example due to an error in measurement of the current me by the measuring device DM or a sudden, insignificant variation in the current measurement me, the monitoring device DS decides on this cessation, in the sub-step 30, only on condition that the difference value ve remains greater than the threshold s1 for a chosen duration d1.

If the deviation value ve remains greater than the threshold s1 for a duration which is strictly less than the chosen duration d1, it (the monitoring device DS) considers that the recharging is taking place normally (and therefore that there is no no leakage current), and therefore we return to perform sub-step 10 with a new me current measurement.

In order to implement this last option, one (the monitoring device DS) can trigger a time delay having the chosen duration d1 as soon as the difference value ve becomes for the first time greater than the threshold s1, and when this time delay expires ( and that we always have ve>s1, without interruption), we (the monitoring device DS) decide on the early interruption of the recharge.

For example, in sub-step 30 of step 10-30, the duration d1 chosen can be between 50 ms and 1 s. By way of illustrative example, the duration d1 can be equal to 300 ms. But other values of duration d1 can be used. For example, the value of the duration d1 can be chosen during the development phase of the vehicle V.

Also for example, in substep 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 = |vi - mc|). Then, one (the monitoring device DS) can determine the deviation value ve by dividing by the informative value vi the result of the multiplication of the absolute value va determined by one hundred (i.e. ve = (va*100)/vi = (|vi - mc|*100)/vi). In this case, the deviation value ve corresponds to a percentage of current loss.

For example, in the presence of the last option in substep 20 of step 10-30, the chosen threshold s1 can be a percentage that is between 3% and 20%. By way of illustrative example, the threshold s1 can be equal to 5%. But other threshold values s1 can be used. For example, the value of the threshold s1 can be chosen during the development phase of the vehicle V.

But in a variant embodiment, the deviation value ve could be equal to the absolute value va, for example.

It will be noted that in sub-step 30 of step 10-30, when the deviation value ve is greater than the threshold s1 (i.e. ve > s1 ), 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 LP battery by preventing a fire from spreading to it. 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.

It will also be noted that in the 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 indicator light on 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 of the dashboard or of a central handset) or on the screen of a smart telephone (or " smartphone”) of the user, and/or broadcast by at least one loudspeaker of the vehicle V or of this smart telephone. Thus, the user is informed of the problem encountered and can, for example, decide to change the power source to perform a new recharge.

It will also be noted that in the 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 (of at least) one fault code which is representative of an early interruption of recharging.

The recording of each fault code is useful for the personnel of an after-sales service which takes charge of 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 when recharging by an SA power source he used.

It will also be noted that in the sub-step 30, when the vehicle V has a navigation function suitable for determining its current geographical position, it is also possible to record with each fault code the geographical position of the vehicle V. Thus, in a after-sales service, it is also possible to inform the user of the vehicle V of the place where the leakage current problem has been detected so that he can determine the power source SA inducing this problem. Customer service can also notify the SA power source manager where the leakage current problem was detected.

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

It will also be noted, as illustrated without limitation in FIG. 2, that the charging computer CC (or the dedicated computer of the monitoring device DS) can 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 DC charging computer (or the dedicated computer of the monitoring device DS) can 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 DC charging computer (or the dedicated computer of the monitoring device DS) can also comprise an IS output interface, in particular for delivering commands to interrupt charging in mode 4, decoupling commands between the battery main BP and the charging connector CN (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.

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

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 informative value indicated and having 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 comparison is made with a threshold chosen a difference 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 difference value is greater than said threshold, ordering to said power source (SA) to cease supplying said recharging current.

2. Method according to claim 1, characterized in that in said step (10-30) said power source (SA) is ordered to cease supplying said recharge current when said deviation value is greater than said threshold during 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 is determined. (BP), 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 difference value is greater than said threshold, said main battery (BP) is decoupled from said charging connector ( NC).

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 phase of charging in mode 4 of a main battery (BP) fitted to 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) and coupled to a charging connector (CN) able to be temporarily coupled to a power source (SA) to receive a current recharging having an indicated informative value and having to supply said main battery (BP) during a recharging 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 difference 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 recharge 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 a mode 4 recharge, characterized in that it further comprises a monitoring device (DS) according to claim 9.