Leak detection method and device for implementing such a method

Abstract

Title: Leak detection method and device for implementing such a method. The invention relates to a method for detecting leaks in an object defining at least one internal volume, said method comprising a step of pressurizing / depressurizing an internal volume from an initial pressure, characterized in that the method comprises, simultaneously with the pressurization / depressurization step, a monitoring step for interrupting the pressurization / depressurization step when the instantaneous pressure / depressurization is outside a predetermined tolerance range around said reference value. Figure for the abstract: Fig. 1

Description

Title of the invention: Leak detection method and device for implementing such a method Scope of the invention

[0001] The field of the invention is that of the design and manufacture of leak detection (or leak measurement) devices in objects defining an internal volume.

[0002] More particularly, the invention relates to a leak detection method and a device enabling the implementation of such a method. State of the art

[0003] The present invention finds an advantageous application for the detection of leaks in objects such as motor vehicle battery packs.

[0004] It should be noted that the term "battery pack" refers to traction and / or functional batteries, generally accompanied by a thermal management system for said battery, intended for use in electric and hybrid vehicles. The thermal management system is, for example, a network of fluid conduits that allows the battery to be cooled or heated as needed.

[0005] These batteries, generally of the Lithium-Ion type, are arranged in specific casings (such as a rigid casing), these casings generally integrating the thermal management system, the whole thus forming a battery pack for motor vehicles.

[0006] With the generalization of hybrid and electric vehicles, and the fact that these battery packs need to be tested, diagnosed and maintained over time and with use, it becomes necessary to have equipment adapted to the maintenance and repair of said battery packs, particularly in garages and repair shops.

[0007] More specifically, there is a demand from manufacturers and garage owners for a simple, ergonomic and effective leak detection device that allows testing the sealing of a battery pack after it has been repaired or serviced / maintained (in particular by testing the sealing of the casing in which battery components and / or the thermal management system of said battery are housed).

[0008] The presence of leaks in the battery casing and / or the thermal management system can have dramatic consequences, or at the very least reduce the battery's efficiency and / or lifespan. Furthermore, this type of device, intended for a garage or industrial environment, must therefore be robust, ergonomic, inexpensive, easy to transport, and easy to use by any operator, whether trained or not.

[0009] Conventionally, a method for detecting leaks in an object defining at least one internal volume, comprising successively: - a step of pressurizing / depressurizing an internal volume from an initial pressure, according to a predetermined leak detection procedure; - a pressure / vacuum stabilization step in said internal volume; - a step of measuring the pressure / vacuum in said internal volume, and - a step of restoring said internal volume to its initial pressure.

[0010] The predetermined leak detection procedure is chosen prior to the start of the process, depending on the object to be tested.

[0011] The procedure includes, in particular, pressure / vacuum values ​​to be achieved during the pressurization / vacuum stage, as well as the durations of each of the stages.

[0012] However, such a process is not without flaws.

[0013] In fact, it may happen that the leak detection process gives erroneous results or does not reach completion.

[0014] This may, for example, be due to a poor choice of procedure by the technician.

[0015] When the chosen procedure is not suitable for the object under test and provides If the pressure / vacuum is below a nominal value, the results obtained will be erroneous.

[0016] When the chosen procedure is not suitable for the object under test and involves a pressure / vacuum exceeding a nominal value, the object may be damaged, rendering it unusable. Indeed, in the event of overpressure (excessive pressure) or excessive vacuum, the object may deform irreversibly, even cracking and becoming porous, or in the worst-case scenario, exploding. Objectives of the invention

[0017] The invention aims in particular to overcome the drawbacks of the prior art.

[0018] More specifically, the invention aims to provide a leak detection method and a device enabling the implementation of said method in order to limit the risks of damage to the object on which it is applied while optimizing the results of leak detection.

[0019] The invention also aims to provide such a method and device which are simple to implement and use. Description of the invention

[0020] These objectives, as well as others that will appear subsequently, are achieved through the invention, which relates to a method for detecting leaks in an object defining at least one internal volume, said method comprising successively: - a step of pressurizing / depressurizing an internal volume from an initial pressure, according to a predetermined leak detection procedure; - a pressure / vacuum stabilization step in said internal volume; - a step of measuring the pressure / vacuum in said internal volume, and - a step of restoring said internal volume to its initial pressure, characterized in that the process comprises, simultaneously with the pressurization / vacuum step, a monitoring step comprising the following sub-steps: - to measure an instantaneous pressure / vacuum within said internal volume during the pressurization / vacuum stage, - compare said instantaneous pressure / vacuum with a reference value corresponding to said predetermined leak detection procedure, and - interrupt the pressurization / depressurization step when the instantaneous pressure / depressurization is outside a predetermined tolerance range around said reference value.

[0021] The monitoring step thus makes it possible to limit the risks of damage to the object on which the process is applied while optimizing the results of leak detection.

[0022] Indeed, interrupting the pressurization / depression step helps to limit the risks of overpressure / depression in the internal volume of the object under test, an overpressure which could cause the object under test to explode or cause irreversible deformation.

[0023] Moreover, this same interruption of the pressurization / depressurization step makes it possible to optimize the test results since when the pressure or depression is too low with regard to the internal volume of the object under test the process is interrupted and it is not possible to obtain erroneous test results.

[0024] Furthermore, this method does not require any special training for test operators since the sub-steps of the monitoring step can be carried out automatically or using common tools already used by test operators such as sensors, nomograms...

[0025] According to an advantageous aspect, the comparison of the instantaneous pressure / depression with the reference value is carried out for at least a predetermined instant.

[0026] By using predetermined times corresponding to characteristic times of the test process, it is possible to detect anomalies in the execution of the process, and thus to stop the process before damaging the object under test.

[0027] According to another advantageous aspect, the comparison of the instantaneous pressure / vacuum with the reference value is carried out for at least two predetermined instants so as to generate a pressure / vacuum curve in said volume internally, said pressure / vacuum curve being used to predict a change in pressure / vacuum during the pressurization / vacuum stage.

[0028] It is thus possible to predict an anomaly in the execution of the leak detection process and to interrupt the process preventively.

[0029] In addition, this makes it possible to limit the execution time of a defective process, that is to say a process following a procedure incompatible with the object to be tested, in order to quickly launch a new process following an appropriate procedure.

[0030] According to another advantageous aspect, the monitoring step also includes a substep of issuing an alert when the pressurization / depressurization step is interrupted.

[0031] This allows an operator to be alerted so that he can act quickly to manually interrupt the process in progress or to isolate the risks to people and / or objects nearby, for example.

[0032] According to another advantageous aspect, the monitoring step also includes a substep of triggering the initial pressure reset step when the pressurization / depressurization step is interrupted.

[0033] Triggering the initial pressure reset step eliminates the danger posed by overpressure, such as overpressure of the internal volume of the object under test.

[0034] According to another advantageous aspect, the tolerance range is between 1% and 10% around the reference value.

[0035] Such an interval makes it possible to limit the risks of damage to the object under test while allowing a margin of error linked for example to a defect in the object under test, said defect being able to locally reduce the internal volume.

[0036] The invention also relates to a leak detection device for implementing the process described above, said device comprising: - a pneumatic circuit comprising a plurality of valves, a pressure sensor, and at least one of a compressor and / or a pump; - at least one connector allowing the pneumatic circuit to be connected to at least one element of an object defining at least one internal volume, and - a control module including a microprocessor and a memory, the control module being configured to control said pneumatic circuit, characterized in that the control module is configured to receive data from the pressure sensor and compare the data received with a reference value stored in the memory, and control the pneumatic circuit according to a result of said comparison.

[0037] The control module makes it possible to limit the risks of damage to the object under test thanks to the data received from the pressure sensor.

[0038] Thus, the continuous presence of an operator is no longer essential since the device becomes autonomous in preventing the risks of damage to the object under test.

[0039] According to an advantageous aspect, the device includes a human-machine interface, said human-machine interface integrating means for issuing an alert.

[0040] In this case, the means of issuing an alert include, for example, at least one of a screen allowing the display of a message and / or an image, a light indicator and a sound device.

[0041] The means of issuing alerts thus make it possible to alert an operator nearby or at a distance of a potential future danger related to the operation of an inadequate leak detection process.

[0042] According to another advantageous aspect, the device also includes a database relating to a plurality of leak detection procedures on objects defining an internal volume, said database being stored in the memory of the control module.

[0043] The database allows the operator to select a detection procedure adapted to the element of the object whose sealing is to be tested.

[0044] According to another advantageous aspect, the database contains a plurality of object references, each associated with a leak detection procedure.

[0045] According to another aspect, the device also includes a communication module with a remote server.

[0046] The communication module allows, for example, one or more of the following data to be downloaded to a remote server: leak test results, identifier of the operator who performed the leak test, identifier of the device, identifier of the object under test, date, and leak test measurement signals. This data allows, in particular, manufacturers of the objects to perform quality monitoring of said objects throughout their service life. The downloaded data is also used to optimize detection procedures, for example, by using machine learning, by generating, for instance, modified parameter sets based on leak detection procedures performed by devices according to the invention. Figures

[0047] Other features and advantages of the invention will become more apparent from the following description of preferred embodiments of the invention, given by way of illustrative and non-limiting examples, and the accompanying drawings described below.

[0048] [Fig-1] Fig. 1 is a schematic front perspective representation of a leak detection device according to the invention.

[0049] [Fig.2] Fig.2 is a schematic rear-perspective representation of the leak detection device according to the invention.

[0050] [Fig.3] Fig.3 is a schematic representation of a pneumatic circuit of the leak detection device according to the invention.

[0051] [Fig.4] Fig.4 is a schematic representation of a control module of the pneumatic circuit of the [Fig.3].

[0052] [Fig.5] Fig.5 is a graph illustrating the evolution of the pressure during of the execution of a leak detection process carried out using the leak detection device according to the invention.

[0053] [Fig. 6] Fig. 6 is a diagram of a leak detection method according to the invention.

[0054] [Fig.7] Fig.7 is a detail of the graph in Fig.5, at a stage of implementation. pressure / depression of an object to be tested. Detailed description of the invention

[0055] Figures 1 and 2 are schematic perspective views, respectively front and rear, of a leak detection device 1 for objects defining at least one internal volume. In the remainder of this description, the object is a battery pack for motor vehicles. Therefore, in the remainder of this description, the terms object and battery pack will be used interchangeably.

[0056] The leak detection device 1 is a device for testing the leak-tightness of at least one battery pack cell by pressure variation. That is, the device is configured to perform a leak detection process in which the pressure in the tested cell is varied (either increasing or decreasing it) up to a predetermined pressure value, and then, after a defined time, the pressure is measured. In a known manner, a leak detection process is carried out according to a procedure corresponding to the type of object being tested, and more specifically to the capacity of its internal volume. A pressure variation between this predetermined value and the final pressure value then indicates that the tested cell has a leak, the device 1 being configured to determine a leak rate based on this pressure change over time.

[0057] The term "battery pack" refers to traction and / or function batteries generally housed in a casing and accompanied by a thermal management system, this assembly forming a battery pack intended for use in electric and hybrid vehicles. This thermal management system includes, for example, a network of fluid conduits for cooling or heating the battery.

[0058] It should be noted that detecting leaks on a battery pack is equivalent to testing the tightness (or level of leakage) of the casing and / or the thermal management system of the battery.

[0059] The volume of the battery casing generally has a volume between 50 and 300 liters, while the volume of the thermal management system generally has a volume between 3 and 50 liters.

[0060] There is no risk of damage (or even explosion) when a crankcase test procedure is selected for testing the thermal management system. This is because the maximum permissible pressure for the thermal management system is significantly higher than the target pressure for the crankcase.

[0061] This is valid whether or not the battery pack has an initial leak.

[0062] However, there is a risk of damage (or even explosion) when a thermal management system test procedure is selected for the crankcase test. This is because the target test pressure for the crankcase is significantly lower than the target test pressure for the thermal management system.

[0063] This risk is valid whether or not the battery pack has an initial leak.

[0064] For a faulty battery pack, i.e., one exhibiting an initial leak or deformation, the risk is established when the test pressure becomes equal to or greater than the pressure permissible by the faulty battery pack. Conversely, the risk is limited or nonexistent when the test pressure is less than the pressure permissible by the faulty battery pack.

[0065] With reference to figures 1 and 2, the device 1 includes in particular a housing 3 and a human-machine interface 5 (also referred to as "HMI" below).

[0066] Said human-machine interface 5 (or user interface) allows, among other things, the device 1 to be started, and the operator to select the operating mode in which the device 1 is to be used, for example, for a leak test of the battery casing or of a battery thermal management system. The interface 5 can thus allow the selection of a leak detection procedure (or leak test procedure) depending on the battery pack to be tested.

[0067] It should be noted that the term human-machine interface 5 refers to all the elements enabling the operator to interact with the device 1, and more specifically to control the device 1 and exchange information with it. The human-machine interface 5 includes, for example, one or more of the following elements: button(s), keyboard, screen, touchscreen, dial(s), indicator lights, etc.

[0068] However, in the embodiment illustrated in [Fig. 1] and [Fig. 2], the human-machine interface 5 includes a touchscreen 5a, as well as a communication port 5b, for example of the USB type. The communication port 5b allows, in particular, to be able to connect to said device 1 via a third-party device (for example to retrieve data, update the device, etc.).

[0069] Said housing 3, for its part, has for example a substantially parallelepiped shape, as well as a front face 3a, a rear face 3b, a lower face 3c, an upper face 3d and lateral faces 3e.

[0070] Said housing 3 also includes support feet 31, at least one winding support 33 and a gripping handle 35.

[0071] Each of the support feet 31 advantageously includes magnets (not shown), which in particular allow the device 1 to be secured to a (ferromagnetic) surface during its use and prevent its inadvertent movement, for example, following a collision or any other external cause.

[0072] The support feet 31 each comprise two parts: a tab 31a (for example, metallic) connected to the housing 3 (at its lower face 3c) and a pad 31b disposed on the distal end of said tab 31a. The pads 31b thus comprise one or more magnets, for example, overmolded, and are generally made of plastic, polymer, or a similar material. These magnetic pads 31b therefore allow the device 1 to be secured to a metallic surface, particularly during the implementation of a leak detection method.

[0073] The support feet 31 are advantageously configured so that the device 1 has an inclination, for example between 10 and 30 degrees relative to the surface (generally the horizontal) on which the device 1 is placed. Thus, the front of the device 1 is raised relative to the rear, facilitating access for the operator to the human-machine interface 5 and more generally simplifying the use of the device 1.

[0074] In an alternative embodiment not shown, only the human-machine interface 5, more particularly the screen 5a, has an inclination, for example between 10 and 30 degrees.

[0075] The winding support 33, for its part, is configured to allow the winding of a power cable and / or a test conduit, such as a flexible air duct. Said winding support 33 comprises, for example, two projections 33a (or tubes, protrusions, etc.) spaced apart from each other, preferably arranged on one of the lateral faces 3e of said device 1.

[0076] The gripping handle 35 is preferably located on the upper face 3d of the housing 3 and facilitates in particular the movement of the device 1 to the place of its use and / or the detachment of the support feet 31 from the surface on which the feet 31 are magnetized.

[0077] Said housing 3 may also include one or more shock-absorbing protectors 37, for example arranged on the corners of the housing 3 (in particular at the faces front 3a and rear 3b), to protect the device and / or the operator in case of impacts. Said protectors 37 are for example made of plastic, rubber, etc., and are in the form of strips surrounding the perimeter (or contour) of the housing 3 (covering said corners of the housing).

[0078] The device 1 also includes a test connector 7 intended to be connected (for example, via the test conduit) to the battery pack under test. The test connector is, for example, located on the rear face 3b of the device 1. The test conduit that connects the device 1 to the battery pack (i.e., to the battery casing and / or thermal management system) includes a suitable connector. The suitable connector and / or the test connector 7 may, in particular, include a keying feature enabling the operator to verify the correct connection or to intervene in the event of an interruption of the leak detection process, as explained below. Other keying or safety features may be used to ensure compatibility between the test conduit and the test connector 7, and between the test conduit and the object under test.

[0079] Said device 1 further includes a power socket 39 for connecting the device 1 to the electrical network, and an On / Off button 41 for switching the device 1 on or off. The power socket 39 and the button 41 are advantageously located on the rear face 3e of the device 1.

[0080] The device 1 according to the invention also includes a pneumatic circuit 100, circuit more particularly illustrated in [Fig.3], said circuit 100 is configured to pressurize or depressurize (“vacuum”) the element of the battery pack whose tightness is to be tested.

[0081] Said pneumatic circuit 100 comprises as follows: - a pump 102 (or a compressor), for example of the volumetric type, configured to pressurize or evacuate the object whose tightness we are trying to test (and therefore connected to the pump 102 via connector 7 and said circuit 100); - a plurality of valves VI, V2 and V3, said valves being configured to allow in particular the filling and / or emptying of at least one element of the battery pack; - a pressure sensor 104, for example an absolute pressure sensor. The said elements of said circuit being connected to each other by means of suitable conduits.

[0082] Said valves VI and V2, respectively first and second valve, are for example 2 / 2 distributors (or one-way valve), while valve V3, or third valve, is for example a 3 / 2 distributor (or two-way valve).

[0083] Valves VI and V2 thus have two positions, open or closed, i.e., two orifices and the ability to allow or prevent fluid circulation between the two ports of said valves. While valve V3 has three ports and two positions, in this case the first and second ports are connected to circuit 100 and the third port is open to atmosphere. Thus, depending on the valve's position, the first or second port is connected to the third, while the remaining port is closed (non-flowing).

[0084] The pump 102 includes a suction inlet or port 102a, and a discharge outlet or port 102b. The inlet 102a of the pump 102 is directly connected to valves V2 and V3, while the outlet 102b is directly connected to valves VI and V3.

[0085] More specifically, the inlet 102a is connected to a first node NI, which is itself connected to a first port of valve V3 and a first port of valve V2. The outlet 102b is connected to a second node N2, which is itself connected to a second port of valve V3 and the first port of valve V2 (valve V3 is therefore arranged in parallel with valves VI and V2). The second ports of valves V2 and V3 are, in turn, connected to a third node N3. Node N3 is connected to connector 7, and the pressure sensor 104 is arranged on the conduit between node N3 and said connector 7.

[0086] Said circuit 100 also includes at least one control module 106 configured, among other things, to control the elements of the pneumatic circuit 100 (the pump 102, the valves Vl-3, etc.). Said control module 106 includes, for example, one or more electronic boards.

[0087] With reference to [Fig.4], the control module 106 comprises: - a 200 microprocessor; - a 202 memory for storing data, such as RAM and non-volatile memory; - a 204 communication module for communicating with remote entities, computers, servers, etc.; - a control module 206 connected to valves VI to V3, to pump 102 and to pressure sensor 104, said module 206 being configured to control the valves and the pump, but also to retrieve the values ​​of measurements made by various sensors, including pressure sensor 104 or environmental sensors (temperature, humidity, atmospheric pressure, etc.).

[0088] Said module 106 may also include a power supply 206 either autonomous or connected to the mains (in particular via the power outlet 39) and configured to convert the input current and voltage into values ​​compatible with the various elements of the module 106 and / or the device 1.

[0089] Said module 106 is also connected to the human-machine interface 5 (link not shown) and includes in memory 202, an operating system managing in particular the interface displayed on screen 5a.

[0090] Furthermore, said device 1 includes a database 210, in particular stored in memory 202 (or coupled to memory 202), relating to battery packs and to the various leak detection procedures, each adapted to the battery pack to be tested (for example, under vacuum or pressure).

[0091] Said database 210 thus comprises a list of motor vehicle models and / or battery pack models in which each model (of battery pack and / or motor vehicle) is associated with a leak detection procedure. For example, database 210 includes, for each listed battery pack, at least one leak detection procedure specific to each of the elements of a battery pack.

[0092] Each of the specific leak detection procedures thus includes leak thresholds enabling the device 1 to determine whether the battery pack has a leak or not.

[0093] Each of the leak detection procedures can thus include one or more of the following parameters: volume of the battery and / or the thermal management system of the battery pack, duration tstab and ttest of the different stages of the leak test, test pressure, filling and / or emptying speed of the tested element of the battery pack, leak threshold.

[0094] The different steps of a leak test are detailed below, but the device 1 is also configured to perform a zeroing (or auto-zero) procedure for the pressure at the pressure sensor 104 when starting said device 1.

[0095] Thus, according to an example, during the zeroing procedure following a purge, there is activation of the pump 102 and opening of the valve VI, while the first node NI is at atmosphere, and the connection of the second node N2 to the valve V3 is closed.

[0096] The pump 102 thus draws in air through the valve V3 (therefore generating a vacuum) and generates an overpressure at the outlet 102b which propagates to the connector 7. This makes it possible to verify that the pressure sensor 104 is functional and that the device 1 is not yet connected to a cell of a battery pack, the activation of the pump 102 thus makes it possible to purge a part of the circuit 100, more particularly the part to which said pressure sensor 104 is connected.

[0097] Said device 1 is also configured to perform a self-test procedure. Said self-test procedure makes it possible to check for leaks in device 1, in particular in circuit 100 and in a test conduit. During a procedure For self-testing, the test output of circuit 100 (with or without the test conduit connected to connector 7) is plugged. A leak detection procedure is then initiated, under pressure and / or vacuum, to verify that there are no leaks in the circuit and / or in the test conduit that could interfere with leak detection on a battery pack cell.

[0098] The leak detection device 1 is a device for testing the leak-tightness of at least one object, for example, a battery pack cell, by pressure variation. That is to say, the device is configured to perform a leak detection process in which the pressure in the tested cell is varied (either increasing or decreasing) until a predetermined pressure value is reached, and then, after a defined time, the pressure is measured. A pressure variation between this predetermined value and the final pressure value indicates that the tested cell has a leak, the device 1 being configured to determine a leak rate based on this pressure change over time.

[0099] Fig. 5 is a graphic illustrating the different stages of a leak detection process (under pressure) carried out by device 1 according to the invention.

[0100] There are thus 4 steps referenced respectively I, II, III and IV: - Step I is the pressurization / depressurization step, i.e., the pressure in the tested element of the battery pack is increased until a predetermined pressure value is reached; - Step II is the stabilization step; indeed, the increase in pressure in the element leads to temperature variations, heat exchanges, etc., which can disrupt the measurement. It is therefore necessary to wait for a predetermined time tstab for the transient phenomena that can disrupt the measurement to fade away; - Step III is the measurement step; the pressure variation measurement during this step allows device 1 to calculate a leak rate (for example, in cubic centimeters per minute) and to determine if the tested element has a leak; and - Step IV is the step of returning the internal volume to its initial pressure; device 1 is configured so that the pressure of the tested element returns to a pressure value substantially close to atmospheric pressure, so that device 1 can be disconnected safely by the operator.

[0101] It should be noted that the leak detection method can also be carried out under vacuum (or negative pressure), that is to say, instead of increasing the pressure in the first step, the pressure in the element to be tested is decreased to a predetermined value. Steps II and III remain unchanged. The fourth step consists of increasing the pressure in the element being tested to a pressure value corresponding to atmospheric pressure. There is therefore a "reversal" of the steps I and IV of pressurization / depressurization and return to initial pressure between the leak detection processes under pressure and vacuum.

[0102] In order to ensure its proper execution and to avoid damage to the object under test, the leak detection method includes, simultaneously with the pressurization / vacuum step I, a monitoring step comprising the following substeps: - measuring 1.1 in said internal volume an instantaneous pressure / vacuum (during the pressurization / vacuum step), - comparing 1.2 said instantaneous pressure / vacuum with a reference value corresponding to said predetermined leak detection procedure, and - interrupting 1.3 the pressurization / vacuum step when the instantaneous pressure / vacuum is outside a predetermined tolerance range around said reference value.

[0103] As illustrated in [Fig.6], following substep 1.2 of comparison, a criterion C of the results of the comparison is carried out to authorize the continuation of the process, namely step II of stabilization (arrow Fl), or on the contrary, to carry out substep 1.3 of interruption of the pressurization / depression (arrow F2).

[0104] The leak detection method and the monitoring step are illustrated by the diagram in [Fig.6], in which step V corresponds to a conclusion step during which the object under test is qualified as compliant (i.e. its leak rate is zero or below an acceptability threshold) or non-compliant (i.e. its leak rate is above an acceptability threshold).

[0105] The reference value is notably included in the execution parameters of the procedure selected for carrying out leak detection.

[0106] The measurement in the internal volume is carried out by the pressure sensor 104. The results of the instantaneous pressure / vacuum measurement are then transmitted to the control module 106 which processes them to determine whether or not it is necessary to interrupt the process.

[0107] More specifically, as described above, the process is interrupted at the pressurization / vacuum step when the instantaneous pressure / vacuum is outside a predetermined tolerance range around said reference value.

[0108] The tolerance range is between X% and Y% around the reference value, where X and Y are numerical values. The values ​​X and Y may be the same or different. By way of example and not limitation, X may be equal to 90 and Y may be equal to 110. In other words, the instantaneous value is considered acceptable when it is between 90% and 110% of the reference value.

[0109] Alternatively, any other method, such as the use of the standard deviation, may be used to determine the tolerance interval around the reference value.

[0110] Figure 7 schematically illustrates a tolerance range around the reference values ​​during a pressurization / depressurization step of the internal volume of an object to be tested.

[0111] The comparison of the instantaneous pressure / vacuum with the reference value is carried out for at least one predetermined instant.

[0112] The predetermined time may, in particular, correspond to a characteristic time of the pressurization / depressurization step. By "characteristic time" is understood a particular time, common to all procedures, at which it is easy to detect an anomaly in the execution of the leak detection process.

[0113] Alternatively, the instantaneous pressure / vacuum is compared with the reference value for at least two predetermined instants so as to generate a pressure / vacuum curve in said internal volume. This pressure / vacuum curve is then used to predict the evolution of the pressure / vacuum during the pressurization / vacuum stage.

[0114] The term “curve” (or curved line) means an object in the plane or in ordinary space, similar to a straight line but not necessarily linear.

[0115] This then makes it possible to predict a possible deviation in the execution of the process, in particular a possible anomaly during the pressurization / depressurization step.

[0116] Advantageously, the device 1, thanks to its human-machine interface 5, allows an operator to choose between a comparison for a single predetermined instant or several predetermined instants, thus allowing the prediction of an anomaly in the execution of the leak detection process.

[0117] When an anomaly is detected, the monitoring step also includes a substep 1.4 of issuing an alert when the pressurization / depressurization step is interrupted.

[0118] For this purpose, device 1 incorporates means for transmitting an alert 51. More specifically, the transmission means are integrated into the human-machine interface 5.

[0119] By way of illustrative and non-limiting example, the means of emitting an alert 51 include at least one of a screen allowing the display of a message and / or an image, a light indicator and a sound device.

[0120] The operator can thus be warned of an anomaly by various means and act accordingly.

[0121] With a view to increased safety, the monitoring step also includes a substep 1.5 consisting of triggering the step of restoring to initial pressure when the pressurization / depressurization step is interrupted.

[0122] This avoids maintaining the object under test under overpressure or underpressure, which could, over time, impair its mechanical resistance and therefore its integrity. Indeed, if the deformation of the object under test is elastic, returning it to the Initial pressure allows the object to recover its original shape, while maintaining pressure / depression could cause the elastic deformation to become plastic deformation and therefore its irreversible deformation.

[0123] Preferably, the return to the initial pressure is carried out smoothly, i.e. the pressure variation is carried out gradually and not abruptly.

[0124] Alternatively, according to certain procedures related to the type of object to be tested, the pressure in the internal volume can be maintained during the interruption of the process in order to avoid irreversible degradation of the object to be tested, for example when the latter seeks to recover an initial shape after having deformed during the execution of the process.

[0125] In fact, the control module 106 is configured to receive data from the pressure sensor 104 and compare the received data or each data point with a reference value stored in memory 202, and control the pneumatic circuit 100 according to a result of said comparison.

[0126] The comparison is carried out by the microprocessor 200 which directly receives the data from the pressure sensor 104. Alternatively, the pressure sensor 104 is of the non-wired type and is in communication with the control module 106 via the control module 204.

[0127] In addition, the communication module can communicate with at least one remote server to exchange data relating to procedures (for example during procedure updates) or to transmit reports of tests carried out successfully or showing anomalies.

[0128] Thus, monitoring of procedures can be carried out and modification of procedures presenting recurring anomalies can be carried out where appropriate.

[0129] In use, when a leak detection method on an object, for example on a battery pack, presents an anomaly, the operator is alerted to said anomaly by means of an alert emission means 51.

[0130] Depending on the operator's choice at the start of the process, the pressurization / vacuum step is interrupted and the pressure in the internal volume is either returned to the initial pressure or maintained constant. In the latter case, the operator decides whether to return the internal volume of the object to the initial pressure based on their observations.

[0131] Thanks to the invention, the risks of damage to the tested objects are limited and the leak detection methods are more secure compared to existing solutions.

Claims

Demands

1. A method for detecting leaks in an object defining at least one internal volume, said method comprising successively: - a step of pressurizing / depressurizing an internal volume from an initial pressure, according to a predetermined leak detection procedure; - a step of stabilizing the pressure / depressurization in said internal volume; - a step of measuring the pressure / depressurization in said internal volume; and - a step of returning said internal volume to its initial pressure, characterized in that the method comprises, simultaneously with the pressurization / depressurization step, a monitoring step comprising the following substeps: - measuring an instantaneous pressure / depressurization in said internal volume during the pressurization / depressurization step, - comparing said instantaneous pressure / depressurization with a reference value corresponding to said predetermined leak detection procedure.and - interrupt the pressurization / depressurization step when the instantaneous pressure / depressurization is outside a predetermined tolerance interval around said reference value, and in that the comparison of the instantaneous pressure / depressurization with the reference value is carried out for at least two predetermined instants so as to generate a pressure / depressurization curve in said internal volume, said pressure / depressurization curve being used to predict an evolution of the pressure / depressurization during the pressurization / depressurization step.

2. A method according to any one of the preceding claims, characterized in that the monitoring step also includes a substep of issuing an alert when the pressurization / depressurization step is interrupted.

3. A method according to any one of the preceding claims, characterized in that the monitoring step also includes a substep of triggering the initial pressure reset step when the pressurization / depressurization step is interrupted.

4. Leak detection device for implementing the method according to any one of the preceding claims, said device comprising: - a pneumatic circuit comprising a plurality of valves, a pressure sensor, and at least one of a compressor and / or a pump;- at least one connector allowing the pneumatic circuit to be connected to at least one element of an object defining at least one internal volume, and - a control module including a microprocessor and a memory, the control module being configured to control the pneumatic circuit, characterized in that the control module is configured to receive data from the pressure sensor and compare the received data or data with a reference value stored in the memory, and control the pneumatic circuit according to a result of said comparison, said comparison of the instantaneous pressure / vacuum with the reference value being carried out for at least two predetermined instants so as to generate a pressure / vacuum curve in said internal volume, said pressure / vacuum curve being used to predict an evolution of the pressure / vacuum during the pressurization / vacuum stage.

5. Device according to the preceding claim, characterized in that it comprises a human-machine interface, said human-machine interface integrating means for issuing an alert.

6. Device according to the preceding claim, characterized in that the means for emitting an alert include at least one of a screen allowing the display of a message and / or an image, a light indicator and a sound device.

7. Device according to any one of claims 4 to 6, characterized in that it also comprises a database relating to a plurality of leak detection procedures on objects defining an internal volume, said database being stored in the memory of the control module.

8. Device according to the preceding claim, characterized in that the database contains a plurality of battery pack references, each associated with a leak detection procedure.

9. Device according to any one of claims 4 to 8, characterized in that it also includes a communication module with a remote server.

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