METHOD FOR INSPECTING A VEHICLE INCLUDING A DEVICE FOR TESTING THE INSULATION OF AN ELECTRICAL CIRCUIT

Abstract

A method for testing a vehicle comprising: - a testing device suitable for implementing the method, - an electrical circuit, - an insulation testing device (102) for the electrical circuit, this electrical circuit comprising: - an electrical energy storage battery (BR1), - at least two power-consuming devices (OD1, C1, CLI) suitable for being powered by the battery (BR1), the battery (BR1) comprising a first device suitable for connecting and electrically isolating it from all the power-consuming devices (OD1, C1, CLI), and each of the power-consuming devices (OD1, C1, CLI) comprising a second device suitable for connecting and electrically isolating it from the battery (BR1) and the other power-consuming devices (OD1, C1, CLI), this method performing: - a step of determining a representative value of the insulation resistance of the electrical circuit,- a control step of the first device so as to isolate the battery (BR1) if the value is strictly less than a first threshold. Figure 1.

Description

Title of the invention: METHOD FOR INSPECTING A VEHICLE COMPRISING A DEVICE FOR TESTING THE INSULATION OF AN ELECTRICAL CIRCUIT

[0001] The invention relates for example to vehicles comprising an electric propulsion device powered by an electrical energy storage battery of sufficient capacity to move the vehicle over several kilometers, called a traction battery.

[0002] Such vehicles are equipped with an electrical circuit comprising: - the traction battery, - at least two power-consuming devices, including an electric drive machine, powered by the traction battery and electrically connected to each other in parallel, the traction battery including a first device designed to electrically isolate it from all consuming devices in the event of an electrical circuit insulation fault.

[0003] Indeed, this type of traction battery operates under a voltage generally between 350 and 800V, so that a fault in insulation of this electrical circuit presents a risk of electrocution for the driver or users of the vehicle, or for any person who comes into contact with a metallic part of the vehicle structure.

[0004] Unfortunately, when this insulation fault appears, the current process causes the traction battery to be isolated by the first device, so that the vehicle breaks down, this breakdown occurring for example in road conditions endangering the occupants of the vehicle and / or road users.

[0005] The aim of the invention is to remedy this deficiency by proposing an improvement to this process.

[0006] To this end, the invention relates to a method for controlling a vehicle comprising: - a control device specifically designed to implement the process, - an electrical circuit, - an electrical circuit insulation testing device, this electrical circuit comprising: - an electrical energy storage battery, referred to as a battery throughout this document, - at least two power-consuming devices that can be powered by the battery, the battery comprising a first device for connecting and electrically isolating it from all the consuming devices, and each of the consuming devices comprising a second device for connecting and electrically isolating it from the battery and the other consuming devices, this method carrying out: - a step of determining a representative value of the insulation resistance of the electrical circuit, - a control step for the first device to isolate the battery if the value is strictly below a first threshold, - a control step of a second predetermined device among the second devices, if the value is between this first inclusive threshold and a second inclusive threshold strictly greater than the first threshold, so as to isolate a predetermined consumer device.

[0007] The term "electrical energy storage battery," referred to as "battery" throughout this document, means an assembly comprising at least one battery module containing at least one electrochemical cell. This battery may include electrical or electronic means for managing the electrical energy of this at least one module. When there are several modules, they are grouped in a casing and thus form a battery pack, this battery pack being often referred to by the English expression "battery pack," this casing forming a hermetically sealed enclosure and generally including a mounting interface and connection terminals.

[0008] Furthermore, the term electrochemical cell throughout the text of this document shall be understood to mean cells generating current by chemical reaction, for example of the lithium-ion (or Li-ion) type, of the Ni-Mh type, or Ni-Cd or lead type.

[0009] The expression "suitable for connecting and isolating it" throughout this document will be understood to mean that the first and second devices allow for both possibilities (connection / isolation), even though, of course, these two possibilities are alternatives since they cannot be simultaneous for the same first or second device. These devices are, for example, power relays or transistors, for example, of the MOSFET type, preferably integrated into the consuming devices or the battery, but can also be located remotely, and assume a closed (connected) or open (isolated) state controlled by the control device.

[0010] The battery is, for example, a traction battery.

[0011] The electrical circuit insulation test device, as well as the step of determining the representative value of the electrical circuit insulation resistance, are known to those skilled in the art; examples will be detailed later.

[0012] Thus, this method presents a gradation on the thresholds of the representative value of the insulation resistance of the electrical circuit, and makes it possible not to necessarily Isolate the battery by applying an intermediate measurement that first isolates the predetermined consumer device if the insulation fault is moderate, i.e., if the value is between this first threshold (inclusive) and this second threshold (inclusive). This method therefore prevents a vehicle breakdown that would occur as a consequence of isolating the battery according to the prior art.

[0013] According to one embodiment of the invention, the at least two battery-powered consumer devices are electrically connected to each other in parallel. In other words, each consumer device is at the same potential as that between the battery terminals.

[0014] It will be noted that the battery, as well as each consumer device, are dipoles whose first pole is conventionally connected to the positive potential "+" of the battery or positive terminal of the battery, and the second pole is connected to the negative potential "-" of the battery or negative terminal of the battery.

[0015] It is understood that the insulation resistance of the electrical circuit is the resistance between one of the two potentials, negative or positive, and a potential referred to as "ground," represented by a metallic structure of the vehicle and / or the battery casing. Therefore, the electrical circuit is, under normal operating conditions, insulated from the metallic structure of the vehicle and / or the battery casing. "Insulated" will be understood to mean an insulation resistance value sufficiently high that users are not at risk of electrocution. The thresholds for this representative value will be quantified subsequently with examples.

[0016] According to one embodiment of the invention, this method performs: - a control step of the second predetermined device, if the value is between this second excluded threshold and a third included threshold strictly greater than the second threshold, so as to maintain the supply of this predetermined consumer device by the battery until the next stop of the vehicle and then to isolate this predetermined consumer device for all subsequent starts of the vehicle.

[0017] Thus the current service of the predetermined consumer device is not disrupted, however this service will no longer be available for future uses of the vehicle (future journeys) which avoids a surprise effect for the driver during the journey.

[0018] According to one embodiment of the invention, this method performs a new step of determining the value after each isolation of the predetermined consumer device, and if the position of this value with respect to the thresholds does not change, the method performs the step of controlling the first device so as to isolate the battery from all the consumer devices.

[0019] Thus, if the insulation fault is not caused by the predetermined consumer device, the vehicle's users are still kept safe by isolating the battery, even if it causes the vehicle to break down.

[0020] Advantageously, if the process detects that the insulation fault is not caused by the predetermined consumer device, the process will perform a step of selecting a second predetermined consumer device before proceeding to isolate the battery.

[0021] According to one embodiment of the invention, the predetermined consumer device includes a heat transfer fluid.

[0022] Indeed, some fluids are corrosive and this corrosion can cause an insulation failure.

[0023] According to one embodiment of the invention, the predetermined consumer device is a vehicle air conditioning compressor.

[0024] According to one embodiment of the invention, the predetermined consumer device is the device with the highest probability of occurrence of an insulation fault among all the consumer devices.

[0025] According to one embodiment of the invention, each probability of occurrence of an insulation fault of each consumer device is a function of intrinsic technical design characteristics of each consumer device.

[0026] According to one embodiment of the invention, each probability of occurrence of an insulation fault is further a function of a usage time of each consuming device.

[0027] According to one embodiment of the invention, each of the thresholds is a function of the consumer devices connected to the electrical energy storage battery by the second devices.

[0028] The invention also relates to a vehicle comprising: - an electrical circuit, - an electrical circuit insulation testing device, This electrical circuit includes: - an electrical energy storage battery, - at least two power-consuming devices designed to be powered by the battery, the battery comprising a first device designed to connect it and to electrically isolate it from all the power-consuming devices, and each of the power-consuming devices comprising a second device designed to connect it and to electrically isolate it from the battery and the other power-consuming devices, - a control device comprising the means of acquisition, processing by software instructions stored in a memory as well as the control means required to implement the process as previously described.

[0029] Other features and advantages will become apparent from the following description of a particular, non-limiting embodiment of the invention, made with reference to figures in which:

[0030] [Fig.1]: illustrates an example of a vehicle to which the method according to the invention applies.

[0031] [Fig.2]: illustrates an electrical circuit to which the method according to the invention applies.

[0032] It should be borne in mind that the figures are given by way of example and are not limiting to the invention. They constitute schematic representations of principle intended to facilitate understanding of the invention and are not necessarily to scale with practical applications. Furthermore, in what follows, reference is made to all the figures taken in combination. When reference is made to one or more specific figures, these figures are to be taken in combination with the other figures for the identification of the designated numerals. The numerals of unchanged elements or elements having the same function are common to all the figures and variant embodiments.

[0033] The vehicle in [Fig. 1] comprises: - a main electrical energy storage battery (BRI), also known as a traction battery, rechargeable, operating under a first high DC voltage, for example 350V, or between 350V and 800V, - a BMS control means for the traction battery BRI, here integrated into the traction battery BRI, and suitable for example for determining a state of charge of the traction battery, this BMS control means for the traction battery BRI including for example an insulation test device 102 of an electrical circuit.

[0034] The vehicle includes this electrical circuit, and this electrical circuit includes, for example: - the BRI traction battery, - a first high-voltage electrical network comprising high-voltage bundles Hcl, Hc2, Hl, H2 operating at the voltage of the traction battery BRI, - an on-board OBC charger, including its own control system, and coupled to the BRI traction battery by a first high-voltage Hcl charging beam, - a current converter Cl, comprising an OBCDC control means for the converter Cl, and being coupled to the traction battery BRI by a second high voltage charging beam Hc2.

[0035] This vehicle also includes: - a second low-voltage direct current electrical network comprising a low-voltage Bl bundle, - a secondary BR2 battery, also known as a service battery, rechargeable, operating on a second low DC voltage, for example 12V, or between 12V and 48V, this secondary battery BR2 being coupled to the current converter Cl by the low voltage harness Bl, this secondary battery BR2 also including a BECB box suitable for example to determine a state of charge of the secondary battery BR2, - electrical equipment El of the vehicle supplied by the secondary battery BR2 via the low voltage harness Bl.

[0036] This vehicle also includes: - a first transmission chain comprising at least one first electric power unit MM1 including a first inverter OD1, and providing torque to drive at least one train Tl from the energy stored in the traction battery BRI, this first power unit MM1 being coupled to the traction battery BRI via the first inverter OD1 by a first high-voltage bundle Hl, - an air conditioning compressor CLI coupled to the traction battery BRI via the first high-voltage bundle H1, or another high-voltage bundle, - optionally a second transmission chain comprising at least a second electric power unit MM2 including a second inverter OD2, and providing torque to drive at least a second train T2 from the energy stored in the traction battery BRI, this second power unit MM2 being coupled to the traction battery BRI via the second inverter OD2 by a second high-voltage bundle H2.

[0037] It will be noted that according to the invention, the electrical circuit further comprises the first inverter OD1, the first high voltage beam H1, the second inverter OD2, the second high voltage beam H2, and the air conditioning compressor CLI.

[0038] It should also be noted that the first inverter OD1, the second inverter OD2, the air conditioning compressor CLI, and the current converter Cl are capable of discharging the traction battery BRI and are therefore power-consuming devices OD1, Cl, CLI within the meaning of the invention, even though all these devices can be reversible and charge the traction battery BRI for short periods. Conversely, the non-reversible on-board charger OBC, that is, one that only has operating modes for recharging the main battery BRI, is not a power-consuming device within the meaning of the invention unless it allows the traction battery BRI to be discharged through a terrestrial electrical grid.

[0039] This vehicle also includes: - a CAN communication network, - a DC control device, also known as vehicle supervision.

[0040] This CAN communication network, for example a CAN serial data bus (CAN stands for "Controller Area Network"), but other types of buses are possible, coupled together: - the BMS control means for the BRI traction battery and the test device 102 insulation of the electrical circuit, - the means of controlling the on-board charger (OBC), - the control method for the OBCDC converter, - the BECB case, - a first means of control (not shown) of the first inverter OD1, - a second control means (not shown) of the second inverter OD2, - the DC control device.

[0041] Thus, for example, the BMS control means of the traction battery BRI transmits, via this CAN communication network, the result of the electrical circuit insulation test device 102 to any control means or device coupled to this CAN communication network, and in particular to the DC control device.

[0042] This CAN communication network is represented on [Fig. 1] by a dashed line, while the first high voltage electrical network and the second low voltage electrical network are represented by a solid "bold" line.

[0043] It should be noted that the first high-voltage electrical network comprises: - the first high-voltage Hcl charging beam, - the second high-voltage Hc2 charging beam, - the first high-voltage Hl beam, - the second high-voltage beam H2.

[0044] This high-voltage beam architecture is just one example, and other architectures saving beam lengths are of course conceivable, such as merging the first high-voltage beam H1 with the second high-voltage beam H2, the underlying idea also being to have only one high-voltage power output (socket) on the traction battery BRI for example.

[0045] It should be noted that the second low voltage electrical network comprises: - the low voltage bundle Bl.

[0046] This low voltage harness architecture is just one example, and other architectures are of course conceivable, for example, taking into account the fact that the vehicle includes more than one electrical equipment.

[0047] In particular, specific electrical equipment will be noted, for example, an electric pump El for circulating the heat transfer fluid of a traction battery cooling system BRI. This heat transfer fluid is, for example, in liquid or gaseous form, such as glycol water, or a dielectric fluid directly immersing the cells.

[0048] This second low-voltage electrical network is in particular the vehicle's on-board network, which for example supplies all the vehicle's DC control means or control devices.

[0049] The first high-voltage electrical network and the second low-voltage electrical network are two networks operating respectively at the first and second voltages, these voltages being, for example, different as previously described. The current converter Cl adapts the voltage from one network to the other according to the desired current direction, in the case of a reversible converter Cl for transferring current from the secondary battery BR2 to the traction battery BRI and vice versa. This current converter Cl is, for example, a DC / DC converter, but not necessarily so. In [Fig. 1], this converter Cl is shown outside the traction battery BRI and the secondary battery BR2, but this is not mandatory and it can be integrated, for example, into the traction battery BRI, at the level of its modules or even its cells.

[0050] In what follows, the vehicle is considered, by way of non-limiting example, to be of the automobile type. For example, a car. However, the invention is not limited to this type of vehicle. It relates to any type of vehicle comprising a transmission system including at least one electric drive unit producing torque to drive at least one set of wheels. Consequently, the invention relates at least to land vehicles.

[0051] The term "electric motive machine" in the entire text of this document means an electric machine (or motor) arranged to provide or recover torque to move a vehicle, either alone or in addition to at least one other possible electric or thermal motive machine (such as, for example, a thermal engine (jet, turbojet or chemical engine)).

[0052] The term electrical equipment El, throughout the text of this document, means electrical equipment powered by the low-voltage network of the secondary battery BR2, this power supply being able to be done without using the current converter Cl and therefore without the aid of the traction battery BRI, and which requires a greater or lesser amount of electrical energy to operate and which may possibly ensure a safety function.

[0053] In the example illustrated, but not limited to, in [Fig. 1], the transmission chain is of the all-electric type and may comprise a single electric power unit MM1. However, the invention is not limited to this type of transmission chain. Indeed, the transmission chain could be of the hybrid type, comprising in addition a thermal power unit associated with at least one train (for example, the second T2), or, as illustrated, a second power unit MM2.

[0054] The transmission chain here comprises, in addition to the first electric drive machine MM1, a transmission shaft and means for coupling this first drive machine to this transmission shaft. The control of at least the first electric drive machine MM1 and the coupling means is ensured by the A DC control device, known as a vehicle monitoring device, operates via the CAN communication network. The DC control device controls the first inverter OD1 of the first power unit MM1.

[0055] The coupling means are here responsible for coupling / decoupling the first electric drive machine MM1 to / from the transmission shaft, on command from the DC control device, in order to transmit the torque it produces, which is defined by a setpoint (torque or speed), using electrical energy stored in the traction battery BRI, to the transmission shaft. The latter is here coupled to the first set of wheels Tl.

[0056] For example, the first train Tl is located at the front of the vehicle V, and preferably so. But in a variant this first train Tl could be located at the rear of the vehicle.

[0057] The coupling means may, for example, be a dog clutch mechanism, a clutch, a hydraulic torque converter, or a brake. They may have at least two coupling states: a first (coupled) state in which they couple the first electric drive machine MM1 to the transmission shaft, and a second (decoupled) state in which they decouple the first electric drive machine MM1 from the transmission shaft. It should be noted that they may also, optionally, have at least one intermediate state (for example, for clutch slippage).

[0058] In the event of the presence of the second drive machine MM2, the control of this second drive machine MM2 will be carried out, mutatis mutandis in the same way by the DC control device.

[0059] The BRI traction battery is arranged to store electrical energy at the first voltage. It can notably be recharged via the OBC on-board charger configured in charging mode to recharge the BRI traction battery, this OBC on-board charger being connected to the terrestrial power distribution network via, for example, a dedicated removable power cord connected to the OBC on-board charger on one side, and to a charging station or a power outlet of the terrestrial power distribution network on the other.

[0060] The term secondary battery, referred to as service battery BR2 throughout the text of this document, will be understood to mean a battery operating under the second voltage (in particular 12V) which is lower than the first voltage.

[0061] The term main battery, referred to as traction battery BRI throughout this document, means a battery operating at the first voltage, which is higher than the second voltage, and which supplies current to the driving machine(s) MM1, MM2. This main battery BRI generally has a much greater energy storage capacity than the secondary battery BR2.

[0062] The OBC on-board charger is shown remotely from the BRI traction battery, but this is not mandatory: it can be fully integrated into the BRI traction battery, at the module or cell level itself, just like the OD1, OD2 inverters, and the Cl converter.

[0063] This on-board OBC charger is for example an AC-DC rectifier converter, and can control the charging in voltage, current, or any other cycle including the charging phase, a discharge phase, a relaxation phase of the BRI traction battery.

[0064] Thus, this DC control device, by means of the CAN communication network, can in particular disable the charging or limit the power consumed by any of the inverters OD1, OD2, the converter Cl, or the on-board charger OBC.

[0065] The method according to the invention is implemented, for example, by means of the DC control device. However, this is not mandatory, and as explained by numerous examples with reference to [Fig. 1], this implementation can be carried out by several control devices distributed throughout the vehicle, or partly grouped in a dedicated computer, these computers receiving the necessary data from various sensors located in the vehicle, via the CAN network, for example.

[0066] These calculators are, for example: - the main battery control system (BMS), - the means of controlling the on-board charger (OBC), - the control method for the OBCDC converter, - the BECB case, - the first control means (not shown) of the first inverter OD1, - the second control means (not shown) of the second inverter OD2, - the DC control device.

[0067] These computers may include a dedicated program, for example. Therefore, a computer or DC control device according to the invention can be implemented in the form of software modules (or computer modules (or "software")), or electronic circuits (or "hardware"), or a combination of electronic circuits and software modules.

[0068] The DC control device and / or the computers include the means of acquisition, processing by software instructions stored in a memory as well as the control means required to implement the process according to the invention.

[0069] The invention therefore relates to a method for controlling a vehicle, in particular the vehicle described above, and comprising: - the DC control device specific to implementing the process, - the electrical circuit, a representation of which is shown in [Fig.2], - the electrical circuit insulation test device 102, this electrical circuit comprising: - the BRI traction battery, - at least two consumer devices OD1, Cl, CLI designed to be powered by the traction battery BRI, the traction battery BRI comprising a first device Klx suitable for connecting and electrically isolating it from all the consuming devices OD1, Cl, CLI, and each of the consuming devices OD1, Cl, CLI comprising a second device K2x, K3x, K4x suitable for connecting and electrically isolating it from the traction battery BRI and the other consuming devices OD1, Cl, CLI, this method executing: - a step of determining a representative value of the insulation resistance of the electrical circuit, - a control step of the first Klx device so as to isolate the BRI traction battery if the value is strictly less than a first threshold, - a control step of a second predetermined device K4x among the second devices K2x, K3x, K4x, if the value is between this first inclusive threshold and a second inclusive threshold strictly greater than the first threshold, so as to isolate a predetermined consumer device CLI.

[0070] This first device Klx and the second devices K2x, K3x, K4x are illustrated in [Fig. 2]. Advantageously, each of these first and second devices comprises two power relays, or power contactors, the index x taking the value 1 or 2 to designate respectively the first Kl1, K21, K31, K41 or the second K12, K22, K32, K42 power relays, or power contactors. For example, for certain isolation of each consuming device, the first power relay, or power contactors Kl1, K21, K31, K41 is at the negative potential of the traction battery BRI, while the second power relay, or power contactors Kl1, K22, K32, K42 is at the positive potential of the traction battery BRI, but other arrangements are of course possible.

[0071] The electrical insulation test device 102 is, for example, an electronic unit that tests the electrical insulation between a first conductive element at a first potential and a second conductive element at a second potential different from the first potential. In this example, the electronic unit is integrated into the traction battery (BRI) and, more specifically, into the BMI control system of the traction battery (BRI). The electrical insulation test device 102 is a known device, already in use and present on the majority of batteries. However, the electrical insulation test device 102 can also be external to the battery pack.

[0072] The first conducting element is, for example, an element of a busbar The traction battery (BRI) is connected to the potential of the negative terminal of the traction battery (BRI) or to the potential of the positive terminal of the traction battery (BRI). The second conductive element is a part of the vehicle's metallic structure or the traction battery (BRI) implicitly connected to a ground potential. There may be several first elements; for example, one is connected to the potential of the positive terminal and another to the potential of the negative terminal. Thus, the electrical insulation test device 102 is electrically connected to the first elements by first electrical connections 23, 24, and to the second element by a second electrical connection 22, as shown in [Fig. 2].

[0073] For example, this known electrical insulation test device 102 comprises: - at least one resistor of known value, connectable via a controlled contactor between the first element and the second element, - a device for measuring the current and voltage between the two terminals of this resistor, - a device for measuring the current output from the BRI traction battery.

[0074] Thus, by the simple Ohm's law, it is possible to determine the value of the insulation resistance of the first element with respect to the second element, in this example the insulation resistance of a positive or negative bus bar (and of all consumer devices (OD1, Cl, CLI) which is connected to it) with respect to the vehicle mass.

[0075] On this principle, one may for example use the knowledge disclosed in the documents of patent FR-A1-3072501 which takes as a reference for comparison the value of voltage measured across the terminals of this resistance of known value, this voltage being representative of the value of the insulation resistance.

[0076] Another example is illustrated by patent document FR-B1-2721407 disclosing a method for the continuous monitoring of the insulation of a high-voltage direct current network, comprising a power supply and a plurality of loads, characterized in that it comprises the following steps: - two respective measurements, under a known measurement impedance, of the voltage between ground and successively two points connected to the DC network and electrically isolated, said measurements being electrically decoupled by a time sequencing; - algebraic difference of the two voltage measurements delivering a fraction of the high voltage DC network voltage obtained through a bridge consisting of a leakage resistance and the measurement impedance; - differential measurement of the network voltage between said points; - comparison of the ratio between the algebraic difference of the two voltage measurements and the differential measurement of the network voltage with a reference threshold fault criterion; - signaling of a leak in the high voltage network in the event of exceeding said reference threshold.

[0077] There are other, more sophisticated methods and devices for testing electrical insulation 102, including in particular a controllable voltage generator. Reference may be made, for example, to French patent document FR-A1-3109222 describing a method for detecting an electrical insulation fault between an electrical power source and an electrical ground, by means of a circuit comprising a controllable voltage generator and a measuring electrical resistor connected in series between a terminal of the electrical power source and the electrical ground, and which also includes a means for measuring the voltage across the measuring electrical resistor.

[0078] It is implied that the electrical insulation test device 102 is not limited to this configuration, and that it can thus test the insulation of multiple elements.

[0079] It should also be noted that all these embodiments of the electrical insulation test device 102 allow for the measurement or determination of the representative value of the insulation resistance of the electrical circuit at any time, either continuously or on demand by sequencing, for example, at the request of the DC control device, and this regardless of the configuration of the electrical circuit at the time of this request. It is therefore entirely possible to measure or determine the representative value of the insulation resistance of the electrical circuit before and after the disconnection or electrical isolation of the predetermined consumer device CLI.

[0080] Figure 2 represents the traction battery BRI comprising at least one MO module. The traction battery BRI has two terminals, conventionally a positive terminal and a negative terminal, to which the high-voltage harnesses H1, H2 are connected. These harnesses are represented in Figure 2 by two electrical lines labeled N for the negative potential and P for the positive potential. Each consumer device OD1, Cl, CLI is connected in parallel to these two electrical lines N, P. The electrical insulation test device 102 is connected to the second element by the second electrical connection 22, which, in Figure 2, connects the electrical insulation test device 102 to a BRI-referenced frame for the traction battery.It is quite clear from the above that this frame is the second element and represents the BRI traction battery casing, which itself is in electrical contact with the vehicle's metallic structure, i.e., in conduction with the vehicle's ground potential. Alternatively, and particularly if the BRI traction battery casing is made of non-conductive composite materials, the second electrical connection 22 is directly connected to the vehicle's metallic structure. Alternatively, this second electrical connection 22 can be multiple and in electrical conduction with several second elements. All power-consuming devices do not... are not represented on [Fig.2], we could for example add the second inverter OD2.

[0081] This process also performs: - a control step of the second predetermined device K4x, if the value is between this second excluded threshold and a third included threshold strictly greater than the second threshold, so as to maintain the supply of this predetermined consumer device CLI by the traction battery BRI until the next stop of the vehicle and then to isolate this predetermined consumer device CLI for all subsequent starts of the vehicle.

[0082] The following values, in ohms, can be taken as an order of magnitude for the thresholds: - first threshold = 800,000 Q, - second threshold = 1,000,000 Q, - third threshold = 2,000,000 Q.

[0083] Advantageously, this process includes, for example, other complementary steps if the value is between this first inclusive threshold and the third inclusive threshold, such as: - a step of memorizing the value, and / or - a step of recording a fault code accessible to after-sales services indicating a necessary change to the predetermined consumer device CLI, and / or - a step involving the activation of a warning light to indicate to the driver that they should go to an after-sales service center, - and / or a step of displaying a message to indicate to the driver a possible failure of the predetermined consumer device CLI.

[0084] Advantageously, this process includes, for example, other complementary steps if the value is strictly less than the first threshold, such as: - a step of memorizing the value, and / or - a step of recording a fault code accessible to after-sales services indicating a necessary change to the predetermined consumer device CLI, and / or - a step to activate a red "stop" light on the dashboard.

[0085] For example, this method performs a new step of determining the value after each isolation of the predetermined consumer device CLI, and if the position of this value with respect to the thresholds does not change, the method performs the step of checking the first device Klx so as to isolate the traction battery BRI from the set of consumer devices OD1, Cl, CLI.

[0086] The predetermined consumer device CLI includes, for example, a ca- fluid loporteur. That is to say, the choice of the predetermined consumer device CLI and pre-recorded in the DC control device and corresponds to the consumer device including this fluid.

[0087] In particular, this predetermined consumer device CLI is a vehicle air conditioning compressor. Specifically, the predetermined consumer device CLI is the device with the highest probability of experiencing an insulation fault among all the consumer devices OD1, Cl, CLI.

[0088] Alternatively, the method determines each probability of occurrence of an insulation fault of each consumer device OD1, Cl, CLI as a function of intrinsic technical design characteristics of each consumer device OD1, Cl, CLI and furthermore as a function of a usage time of each consumer device OD1, Cl, CLI.

[0089] This usage time is, for example, a cumulative time during which the consuming device actually draws current from the traction battery. However, this usage time can also be an equivalent time comprising a combination of the cumulative time during which the consuming device actually draws current from the traction battery, a period of time elapsed without use in addition to the previous one, and a cumulative amount of energy consumed by the consuming device. Other factors affecting the aging of the insulation of the consuming devices can also be taken into account, such as maximum or average operating temperatures, predominant driving types (e.g., economy, sport, comfort), the ambient temperature of the vehicle, and humidity conditions; this list is not exhaustive.

[0090] Alternatively, each threshold is a function of the consuming devices OD1, Cl, CLI connected to the traction battery BRI by the second devices K2x, K3x, K4x. "Connected" will be understood to mean that the second device K2x, K3x, K4x is in the closed position and that current is actually being consumed. However, the value of these thresholds will not be below the values ​​below: - first threshold = 800,000 Q, - second threshold = 1,000,000 Q, - third threshold = 2,000,000 Q.

[0091] This arrangement allows for improved sensitivity in detecting insulation faults. Indeed, if we consider the electrical circuit as new, meaning that each OD1, Cl, CLI consumer device has a nominal insulation resistance, the more OD1, Cl, CLI consumer devices are connected to the main battery BRI, by connecting each OD1, Cl, CLI consumer device in parallel, the lower the equivalent nominal insulation resistance becomes, and conversely, the fewer OD1, Cl, CLI consumer devices there are. The more connected the devices, the higher the equivalent nominal insulation resistance. The risk is that if the equivalent nominal insulation resistance is high, an insulation fault or incipient insulation fault in just one of the consuming devices OD1, Cl, CLI may not reduce the equivalent insulation resistance below one of the three thresholds, unless, as explained above, these thresholds are adapted according to the consuming devices OD1, Cl, CLI connected to the traction battery BRI.

[0092] As previously stated, this method is advantageously applicable to a vehicle comprising: - the electrical circuit, - the electrical circuit insulation test device 102, this electrical circuit comprising: - the BRI traction battery, - at least the two consumer devices OD1, Cl, CLI designed to be powered by the traction battery BRI, the traction battery BRI comprising the first device Klx suitable for connecting and electrically isolating it from all the consuming devices OD1, Cl, CLI, and each of the consuming devices OD1, Cl, CLI comprising the second device K2x, K3x, K4x suitable for connecting and electrically isolating it from the traction battery BRI and the other consuming devices OD1, Cl, CLI, - the DC control device including the means of acquisition, processing by software instructions stored in a memory as well as the control means required to implement the process as previously described.

Claims

Claims

1. Method for controlling a vehicle comprising: - an electrical circuit, - an insulation testing device (102) for the electrical circuit, this electrical circuit comprising: - an electrical energy storage battery (BRI), - at least two consumer devices (OD1, Cl, CLI) capable of being powered by the battery (BRI), the battery (BRI) comprising a first device (Klx) capable of connecting it and electrically isolating it from all the consumer devices (OD1, Cl, CLI), and each of the consumer devices (OD1, Cl, CLI) comprising a second device (K2x, K3x, K4x) capable of connecting it and electrically isolating it from the battery (BRI) and from the other consumer devices (OD1, Cl, CLI), this method executing: - a step of determining a value representative of the insulation resistance of the electrical circuit,- a step of controlling the first device (Klx) so as to isolate the battery (BRI) if the value is strictly lower than a first threshold, characterized in that the method further executes: - a step of controlling a second predetermined device (K4x) among the second devices (K2x, K3x, K4x), if the value is between this first threshold inclusive and a second threshold included strictly higher than the first threshold, so as to isolate a predetermined consumer device (CLI).,

2. Method according to claim 1, performing: - a step of controlling the second predetermined device (K4x), if the value is between this second excluded threshold and a third included threshold strictly greater than the second threshold, so as to maintain the power supply of this predetermined consumer device (CLI) by the battery (BRI) until the next stop of the vehicle then to isolate this predetermined consumer device (CLI) for all future starts of the vehicle.

3. Method according to one of the preceding claims, performing a new step of determining the value after each isolation of the predetermined consumer device (CLI), and if the position of this value relative to the thresholds does not change, the method executes the control step of the first device (Klx) so as to isolate the battery (BRI) from all the consumer devices (OD1, Cl, CLI).

4. Method according to one of the preceding claims, the predetermined consumer device (CLI) comprising a heat transfer fluid.

5. Method according to claim 4, the predetermined consumer device (CLI) being an air conditioning compressor of the vehicle.

6. Method according to one of claims 1 to 3, the predetermined consumer device (CLI) being the device having the greatest probability of occurrence of an insulation fault among all the consumer devices (OD1, Cl, CLI).

7. Method according to claim 6, each probability of occurrence of an insulation fault of each consumer device (OD1, Cl, CLI) being a function of intrinsic technical design characteristics of each consumer device (OD1, Cl, CLI).

8. Method according to claim 7, each probability of occurrence of an insulation fault being further a function of a usage time of each consumer device (OD1, Cl, CLI).

9. Method according to one of the preceding claims, each of the thresholds being a function of the consumer devices (OD1, Cl, CLI) connected to the electrical energy storage battery (BRI) by the second devices (K2x, K3x, K4x).

10. vehicle comprising: - an electrical circuit, - a device for testing the insulation of the electrical circuit (102), this electrical circuit comprising: - an electrical energy storage battery (BRI), - at least two consumer devices (OD1, Cl, CLI) capable of being powered by the battery (BRI), the battery (BRI) comprising a first device (Klx) capable of connecting it and electrically isolating it from all the consumer devices (OD1, Cl, CLI), and each of the consumer devices (OD1, Cl, CLI) comprising a second device (K2x, K3x, K4x) capable of connecting it and electrically isolating it from the battery (BRI) and from the other consumer devices (OD1, Cl, CLI), - a control device comprising the means of acquisition, processing by software instructions stored in a memory as well as the control means required to implement the method according to any one of the preceding claims.

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