Method for determining a probe signal, method for inspecting and detecting a fault within an electrochemical system using such a signal

Abstract

One aspect of the present invention relates to a method (100) for determining a probe signal for acoustically interrogating an electrochemical system (BAT), the method comprising: a step (1E1) of transmitting a first signal, referred to as a calibration signal (SC), comprising a wave train of a plurality of frequencies, each frequency having the same associated spectral density; a step (1E2) of receiving a response (RE) of the electrochemical system (BAT) to the calibration signal (SC); a step (1E3) of determining, for each frequency of the calibration signal (SC) based on the received response (RE); a step (1E4) of determining, for each frequency of the calibration signal (SC), a correction factor in accordance with the attenuation factor, such that a correction factor is associated with each frequency of the calibration signal (SC); and a step (1E5) of determining a probe signal (SS) obtained by multiplying the spectral density associated with each frequency of the calibration signal (SC) by the correction factor corresponding to that frequency.

Description

Technical Field

[0001] The technical field of the present invention is the field of non-invasive diagnosis and operation of electrochemical systems (cells, batteries, fuel cells, etc.) that convert energy.

[0002] The present invention relates to the determination of probe signals and the use of such signals in monitoring and detecting faults in electrochemical systems. The present invention also relates to a device configured to perform such detection. Execution

Background Art

[0003] Systems for monitoring and managing batteries are essential for effectively meeting the requirements of users as much as possible. Generally, monitoring and management systems consider the charging stage of the battery, the state of health of the battery, and / or the safety state of the battery (detection of abnormal operation). This various information is generally obtained by measuring the magnitude of electricity at the terminals of the battery, but can also be obtained by external data such as thermal analysis techniques (measurement of temperature and / or heat flux) or provided by non-destructive control (e.g., acoustic characterization). From the information obtained by the measurement, the management system adjusts the operation of the battery to optimize its performance and ensure the safety of the assembly.

[0004] However, currently proposed techniques for monitoring an operating battery via ultrasonic acoustic signals (Gold et al., 2017; Sood, Pecht, and Osterman, 2016; Steingart et al., 2016, DE102015210266A1) have several drawbacks. First, these techniques only consider specific operation indicators of the battery that are independent of each other (state of charge, state of health, temperature, detection of faults), and do not always take into account all of the information contained in the measured acoustic signal.

[0005] Subsequently, the specific parameters of the incident acoustic signal used are often selected more or less arbitrarily, without considering the particularities of each battery. As a result, relevant information for the optimal management of the battery is lost, and it becomes impossible to take into account the changes in the characteristics of the battery over its service life.

[0006] Finally, in most of the work, incident signals in the form of pulses with short durations (from several tens of nanoseconds to several milliseconds) are used, thereby making it impossible to establish a steady state State within the battery, and thus limiting the capabilities of the mathematical tools used to analyze the signals.

[0007] The selection of the frequency of the incident signal is very important. This substantially depends on the experimental assembly used (characteristics of the transducers used for the transmission of the incident signal and the reception of the transmitted signal, geometric particularities of the battery being tested, properties of the materials constituting the battery, etc.), the information expected (flight time of the transmitted signal, frequency, or measurements of time analysis), and the structural characteristics of the material for which changes are desired to be monitored (thin layers of electrodes, high-density or porous materials, etc.).

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0009] Therefore, an effective method is needed that enables the determination of the optimal parameters (frequency, duration, amplitude) of the incident acoustic signal in order to detect the fluctuations and changes of the transmitted signal with maximum accuracy.

Means for Solving the Problems

[0010] The present invention provides a solution to the above-mentioned problems by enabling the determination of the characteristics of probe signals specific to electrochemistry systems that are acoustically tested. In addition, the adaptability of the probe signals allows for considering different operating conditions, considering changes in the electrochemistry system over its lifetime, and detecting anomalies in the operation of the electrochemistry system.

[0011] For this reason, a first aspect of the present invention relates to a method for determining a probe signal for acoustically Search testing an electrochemistry system, the method comprising: - transmitting a first signal called a calibration signal that includes wave trains of a plurality of frequencies, wherein the spectral density associated with each frequency is the same; - receiving a response of the electrochemistry system to the calibration signal; - determining a signal attenuation coefficient for each frequency of the calibration signal based on the received response; - determining a correction coefficient for each attenuation coefficient according to the attenuation coefficient so as to associate a correction coefficient with each frequency of the calibration signal; - determining a probe signal, wherein the probe signal is obtained by multiplying the spectral density associated with each frequency of the calibration signal by the correction coefficient corresponding to that frequency.

[0012] According to the present invention, the determined probe signal takes into account the specificity of the electrochemistry system to be tested. In addition, the response of the system to the probe signal includes a characteristic spectral density, and changes in it can be easily observed, thus significantly improving the detection of aging or faults in the electrochemistry system. Search In addition to the features described in the previous paragraph, the method according to the first aspect of the present invention can have one or more additional features from the following, individually or in any technically acceptable combination.

[0013] ​

[0014] The spectral density (and thus the amplitude) associated with each frequency within the calibration signal is advantageously selected to induce a linear response of the electrochemical system.

[0015] The duration of the calibration signal is advantageously long enough to establish a steady regime in the response of the electrochemical system.

[0016] Frequencies associated with attenuation coefficients greater than a predetermined threshold are advantageously not considered in the determination of the probe signal.

[0017] During the step of transmitting the first signal, the calibration signal is advantageously transmitted while the electrochemical system is in a reference state.

[0018] A second aspect of the present invention relates to a method for testing the suitability of an electrochemical system to be tested with respect to a reference electrochemical system, the method comprising: - on a reference electrochemical system Execution determining a probe signal using the method according to the first aspect of the invention as carried out; for each calibration electrochemical system of a plurality of calibration electrochemical systems, - transmitting the probe signal determined above; - receiving the response of the calibration electrochemical system to the probe signal, thus obtaining a statistical value of the response of the calibration system; the method also comprising: - transmitting a probe signal within the electrochemical system to be tested; - receiving the response of the electrochemical system to be tested to the probe signal; - comparing the response of the electrochemical system to be tested with the statistical value of the response of the calibration electrochemical system so as to detect a malfunction of the electrochemical system to be tested.

[0019] A third aspect of the present invention relates to a method for detecting a fault in an electrochemical system, the method comprising: - determining a probe signal using the method according to the first aspect of the present invention; - transmitting the probe signal determined above; - receiving a response of the electrochemical system to the probe signal; - analyzing the response to detect a fault in the electrochemical system.

[0020] The steps of transmitting the probe signal, receiving the response of the electrochemical system, and analyzing the response are preferably repeated at regular or variable time intervals.

[0021] In addition to the features described in the previous paragraph, the method according to the third aspect of the present invention can have one or more additional features, individually or in any technically acceptable combination, selected from the following.

[0022] During the step of determining the probe signal, it is advantageous for the probe signal to be determined while the electrochemical system is in a reference state.

[0023] The steps of transmitting the probe signal, receiving the response of the electrochemical system, and analyzing the response are performed each time the electrochemical system reaches the reference state used to determine the probe signal during the step of determining the probe signal. Execution This is advantageous.

[0024] The step of analyzing the response comprises: - determining the spectral density of the response to the probe signal; - storing the spectral density of the response to the probe signal; - A sub-step of comparing the determined spectral density with the statistical value of the response, wherein the statistical value of the response precedes the step of storing the spectral density of the response to the probe signal Execution and is determined from the spectral density stored therein; a sub-step - A sub-step of detecting a fault in the electrochemical system when the difference between the spectral density determined during the sub-step of determination and the statistical value of the response is greater than a predetermined value is advantageously included.

[0025] Advantageously, the probe signal is determined again at regular intervals or in response to the user's request.

[0026] During the step of analyzing the response, it is advantageous that a malfunction of the electrochemical system is detected when the rate of change of the response deviates beyond a predefined threshold value. The rate of change of the response is defined as the value obtained by dividing the difference between the last two measured responses by the time separating these two measurements.

[0027] Advantageously, the method according to the third aspect of the invention includes the step of transmitting a signal to a management system responsible for the electrochemical system when a fault is detected.

[0028] The method according to the third aspect of the invention, after the step of analyzing the response to detect a fault in the electrochemical system: - Determining a new probe signal using the method according to the first aspect of the invention with a correction factor stored - Analyzing the change in the correction factor to detect possible faults is advantageously included.

[0029] The fourth aspect of the invention relates to a device comprising means configured to perform the method according to the first, second, or third aspect of the invention Execution thereof.

[0030] The fifth aspect of the present invention relates to a computer program that, when executed by a computer, causes the computer to perform the method according to the first, second, or third aspect of the present invention. Execution It relates to a computer program including instructions for causing the computer to perform the method according to the first, second, or third aspect of the present invention.

[0031] The sixth aspect of the present invention relates to a computer-readable storage medium on which the computer program according to the fifth aspect of the present invention is recorded.

[0032] The present invention and its various applications will be better understood when the following description is read and the accompanying drawings are examined.

[0033] These drawings are presented for informational purposes and do not limit the present invention.

Brief Description of the Drawings

[0034]

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Figure 11

[0035] These figures are presented for informational purposes and do not limit the present invention. Hereinafter, the term "spectral density of a signal" refers to the power spectral density of the signal. Similarly, the term "frequency" related to the present invention corresponds to a frequency bandwidth centered on the said frequency, and its value is corrected by the parameters of the measurement, and more specifically, by the ratio between the measurement bandwidth and the sampling of the selected frequency.

[0036] Determination of probe signal The first aspect of the present invention shown in [FIG. 1] relates to a method 100 for determining a probe signal SS for acoustically Search acting on the electrochemical system BAT. As will be detailed below, the method 100 according to the first aspect of the present invention makes it possible to determine a probe signal SS constructed to generate a specific response RE (or an expected response RE) of an assembly comprising the electrochemical system BAT and a transducer that generates a signal. Also, the method 100 according to the first aspect of the present invention makes it possible to obtain a probe signal SS that can change over time in order to monitor changes in the electrochemical system BAT. Hereinafter, for the sake of brevity, reference is made to the response RE of the electrochemical system BAT in order to designate the specific response RE (or the expected response RE) of the assembly comprising the electrochemical system BAT and the transducer that generates the probe signal SS.

[0037] For this reason, method 100 according to a first aspect of the present invention includes step 1E1 of transmitting a first signal called a calibration signal SC including a train of waves at a plurality of frequencies, preferably with the spectral density associated with each frequency being the same. In one embodiment, the calibration signal SC is generated by a piezoelectric transducer PZ1 fixed on the electrochemical system BAT. In one embodiment, the duration of the calibration signal SC is long enough to establish a steady state regime in the response of the electrochemical system BAT.

[0038] In one embodiment, the spectral density (and thus the amplitude) of the calibration signal SC is selected to ensure the linearity of the response RE of the electrochemical system BAT. To check this condition, the calibration signal SC can be transmitted continuously at different amplitudes, for example by adjusting the voltage of the signal transmitted to the piezoelectric transducer PZ1. For all measurements, the energy of the transmitted signal (i.e., the response RE of the electrochemical system BAT) must be proportional to the energy of the transmitted calibration signal SC.

[0039] In one embodiment, the calibration signal SC is defined by the frequency range (minimum and maximum frequencies) under consideration, the sampling frequency (the precise frequencies at which the incident signal is composed), the spectral density associated with each frequency, and the number of consecutive periods required at each frequency to reach the steady state regime.

[0040] Next, method 100 according to a first aspect of the present invention includes step 1E2 of receiving the response RE of the electrochemical system BAT to the calibration signal SC. The reception can be performed by a transducer PZ2 (e.g., a piezoelectric transducer) fixed to the electrochemical system BAT.

[0041] The signals measured during the transmitting step 1E1 and the receiving step 1E2 are shown in [Figure 2], where the calibration signal SC and the response RE of the electrochemical system BAT are shown. In this figure, it is possible to identify two relative transition regimes at the beginning and end of the calibration signal SC, as well as the steady-state regime in the response of the electrochemical system BAT. Obtaining the steady-state regime in the response RE of the electrochemical system BAT is preferred for determining the probe signal SS. Thus, the calculations required to obtain the probe signal SS described below are preferably used from the data acquired in the steady-state regime.

[0042] As shown in [Figure 3], from the perspective of frequency, it is possible to analyze the transmitting step 1E1 and the receiving step 1E2 by considering the spectral density of the calibration signal SC ("transmission") and the response of the electrochemical system BAT ("reception") according to the frequency. In the example shown in [Figure 3], the spectral density of the received signal (i.e., the response RE of the electrochemical system BAT) varies substantially over the measured frequency range, while the spectral density of the calibration signal SC is constant over most of the frequency band.

[0043] The frequency band is generally selected from previous measurements on the same system BAT and / or according to the nature and characteristics of the transducers PZ1, PZ2 used for the generation of the calibration signal SC (or the probe signal SS) and / or the measurement of the response RE of the electrochemical system BAT.

[0044] From this information, it is possible to consider attenuating the received signal, i.e., the response RE of the electrochemical system BAT, by comparison with the transmitted signal, i.e., the calibration signal SC. For this reason, the method according to the invention also includes step 1E3 of determining a signal attenuation coefficient for each frequency of the calibration signal SC based on the received response RE. The attenuation for a given frequency can be defined as the value obtained by dividing the spectral density of the received signal (i.e., the response RE of the system) at the given frequency by the spectral density of the transmitted signal (i.e., the calibration signal SC) at the given frequency. The greater the attenuation for a given spectral density of the calibration signal SC at the same frequency, the smaller the spectral density of the response RE of the electrochemical system BAT. This step is shown in [Figure 4a] and [Figure 4b]. [Figure 4a] illustrates the spectral density of the response RE of the electrochemical system BAT with respect to the calibration signal SC. As indicated by the dotted line in this figure, the calibration signal SC is characterized by a substantially constant spectral density over the frequency band. [Figure 4b] illustrates the attenuation coefficient associated with each frequency, and the further the spectral density of that frequency is from the dotted line, the higher the attenuation coefficient.

[0045] Subsequently, it is possible to determine correction coefficients from these attenuation coefficients and then apply those correction coefficients to the calibration signal SC to obtain the probe signal SS. For this reason, method 100 according to the first aspect of the invention includes step 1E4 of determining a correction coefficient according to the attenuation coefficient for each attenuation coefficient so as to associate a correction coefficient with each frequency of the calibration signal SC. This step is shown in [Figure 5a] and [Figure 5b]. As can be seen in these two figures, a high attenuation coefficient (compared to others) is associated with a high correction coefficient (compared to others). This relationship is understood in that the correction coefficient attempts to offset the effect of the attenuation.

[0046] As described above, the correction factor is then used to determine the probe signal SS from the calibration signal SC that enables these correction factors to be determined. For this reason, the method according to the first aspect of the present invention includes step 1E5 of determining the probe signal SS, and the probe signal SS is obtained by multiplying the spectral density associated with each frequency of the calibration signal SC by the correction factor corresponding to that frequency. [FIG. 6] illustrates in [FIG. 6a] the representation of the spectral density of the calibration signal SC, and in [FIG. 6b] the correction factor determined in a preceding step that enables the response RE as shown in [FIG. 6d], i.e., a response RE having a substantially constant power spectral density, to be obtained. The spectral density of the probe signal SS shown in [FIG. 6c] that enables this response RE to be obtained is obtained by multiplying the spectral density of the calibration signal SC associated with each frequency by the corresponding correction factor.

[0047] In one embodiment, the correction factor associated with each frequency (as already introduced, as shown in [Fig. 6b]) is selected such that the spectral density associated with each frequency in the response RE of the electrochemical system BAT during the transmission of the probe signal SS becomes substantially the same for each frequency (as already introduced, as shown in [Fig. 6d]). By having a response RE to the probe signal SS with a substantially constant spectral density over the entire frequency range, it becomes possible to very easily identify with high precision the variations observed during the operation of the electrochemical system BAT. Then, it is possible to quantify the variation of the energy of the transmitted signal with respect to a reference value and identify the frequency at which the relative variation is the largest. This comparison function is further enhanced when the probe signal SS is acquired with respect to a reference state and the comparison is made between two measurements performed with respect to this same reference state. In an alternative embodiment, the correction factor associated with each frequency is selected such that the spectral density associated with each frequency in the response RE of the electrochemical system BAT to the transmission of the probe signal SS increases or decreases with that frequency. In an alternative embodiment, the correction factor associated with each frequency is selected such that the spectral density associated with each frequency in the response RE of the electrochemical system BAT to the transmission of the probe signal SS is a parabolic function of that frequency.

[0048] In one embodiment, frequencies associated with attenuation factors greater than a predetermined threshold are not considered. For example, only the frequencies of the response RE of the electrochemical system BAT having a power spectral density greater than 30 dB / Hz are retained.

[0049] Regarding a clearly defined state of the electrochemical system BAT called the reference state, it is advantageous to determine the probe signal SS. As can be seen below, such a reference state can have advantages in monitoring the change of the electrochemical system BAT over time. For this reason, in one embodiment, during step 1E1 of transmitting the first signal, the calibration signal SC is transmitted while the electrochemical system BAT is in the reference state. For example, when the electrochemical system BAT is a battery, the reference state can correspond to a given state of charge. In one embodiment, this reference state can be associated with some operating conditions of the electrochemical system BAT. For example, when the electrochemical system BAT is a battery, the reference state can correspond to a given state of charge of the battery, and a given temperature, or a given state of charge of the battery, a given temperature, and a given supply current.

[0050] Quality control of electrochemical system Subsequently, it is possible to characterize the state of the electrochemical system BAT from the probe signal SS determined using the method 100 according to the first aspect of the present invention. A first possible application is the quality control of the electrochemical system BAT in a production line. This production line then produces an electrochemical system BAT suitable for testing at the exit of the production chain. For this reason, each electrochemical system BAT at the production exit is compared with the statistical value of the response RE established over a plurality of calibrated electrochemical system BATs, and this statistical value is obtained using the probe signal SS determined from the reference electrochemical system BAT corresponding to the desired product. Therefore, this comparison or quality control can be performed by utilizing a probe signal SS such as that determined by the method 100 according to the first aspect of the present invention.

[0051] For this reason, the second aspect of the present invention shown in [Figure 7] relates to a method 200 for inspecting the compatibility of the electrochemical system BAT to be inspected with respect to the reference electrochemical system BAT.

[0052] Method 200 according to a second aspect of the present invention includes step 2E1 of determining a probe signal SS using method 100 according to a first aspect of the present invention, and said method 100 is performed on a reference electrochemical system BAT Execution This step makes it possible to obtain a probe signal SS corresponding to the target quality on the production line.

[0053] After the probe signal SS is determined, it is necessary to establish a statistical value of the response RE to this probe signal SS. For this purpose, method 200 according to a second aspect of the present invention includes step 2E2 of transmitting the probe signal SS determined above to each calibration electrochemical system BAT among a plurality of calibration electrochemical systems BAT; and step 2E3 of receiving the response RE of the calibration electrochemical system BAT to the probe signal SS. Thus, a statistical value of the response RE to the probe signal SS is constructed, and then this statistical value can be used to inspect the electrochemical system BAT exiting the production chain.

[0054] For this purpose, method 200 according to a second aspect of the present invention includes step 2E4 of transmitting the probe signal SS within the electrochemical system BAT to be inspected; step 2E5 of receiving the response RE of the electrochemical system BAT to be inspected to the probe signal SS; and step 2E6 of comparing the response RE of the electrochemical system BAT to be inspected with the statistical value of the response of the calibration electrochemical system BAT so as to detect a failure of the electrochemical system BAT to be inspected.

[0055] In one embodiment, the electrochemical system BAT involved in method 200 according to a second aspect of the present invention is in the same reference state when the probe signal SS is determined or when the determined probe signal SS is applied thereto.

[0056] Monitoring of the operating electrochemical system BAT The probe signal SS determined by the method 100 according to the first aspect of the present invention can also be used to monitor the electrochemical system BAT during its operation. For this purpose, the third aspect of the present invention shown in [FIG. 8] relates to a method 300 for detecting a fault in the electrochemical system BAT.

[0057] The method 300 according to the third aspect of the present invention includes a step 3E1 of determining the probe signal SS using the method 100 according to the first aspect of the present invention. In other words, on the electrochemical system BAT for which monitoring is desired, the method 100 according to the first aspect of the present invention is Execution performed.

[0058] Next, the method 300 according to the third aspect of the present invention includes a step 3E2 of transmitting the probe signal SS so as to acquire an acoustic response of the electrochemical system BAT.

[0059] Next, the method 300 according to the third aspect of the present invention includes a step 3E3 of receiving a response of the electrochemical system BAT to the probe signal SS. Here, it is interesting to note that since the probe signal SS is obtained using the method 100 according to the first aspect of the present invention, the expected response is known. Therefore, it becomes very easy to check whether the response obtained during this step conforms to the expected response.

[0060] For this reason, then, the method according to the third aspect of the present invention includes a step 3E4 of analyzing the response so as to detect a possible fault in the electrochemical system.

[0061] Preferably, to ensure monitoring during the operation of the electrochemical system BAT, the step 3E2 of transmitting the probe signal SS, the step 3E3 of receiving the response of the electrochemical system BAT, and the step 3E4 of analyzing the response are repeated at regular time intervals or variable time intervals.

[0062] In one embodiment, two of these stepsExecution The time interval between them is variable, and the time steps associated with the electrochemical system BAT in use (such as large current, high temperature, etc.) are smaller than the time steps associated with the electrochemical system BAT not in use (such as zero current, etc.).

[0063] As detailed below, the analysis of the response RE of the electrochemical system BAT to the probe signal SS can be carried out in several ways. This analysis can consist, for example, of a comparison for each frequency of the expected response and the response measured during step 3E3 of receiving the response of the electrochemical system BAT. Such an example of detecting a defect from the measurement of the response RE of the system is shown in [Figure 9]. [Figure 9a] shows the expected response RE to the probe signal SS, as well as the tolerance defining the difference associated with the expected response RE that can be considered normal. [Figure 9b] shows the response RE corresponding to the state without a fault, and [Figure 9c] shows the response RE corresponding to the state with a fault, and the part of the response RE that causes the defect is indicated by a black circle. Thus, [Figure 9] shows how the determination of the tolerance is facilitated by using the probe signal SS associated with the expected response RE of the electrochemical system BAT.

[0064] Alternatively or in addition, this analysis can include the calculation of the convolution between the spectral density of the expected response RE and the spectral density of the acquired response RE. More generally, any method of comparing two signals can Execution be used, and a difference that is too large between the expected response RE and the acquired response RE is evidence of a fault within the electrochemical system BAT. As shown below, this comparison can also be made from the statistical values of the response of the electrochemical system BAT to the probe signal SS.

[0065] For the reference state of the electrochemical system BAT for which it is desired to ensure monitoring, using the determined probe signal SS, the method 300 according to the third aspect of the present invention ExecutionIt is advantageous to do so. In fact, as already detailed, using the reference state has certain advantages in terms of the function of detecting possible obstacles. For this reason, in one embodiment, during step 3E1 of determining the probe signal SS, the probe signal SS is determined while the electrochemical system BAT is in the reference state. Preferably, this reference state is defined with respect to the application composed of the electrochemical system BAT and / or the mission profile of the electrochemical system BAT. This reference state can be selected, for example, not only at the maximum charge state, zero current, and defined temperature range, but also at a partial charge state, current, and defined temperature range.

[0066] It is useful to note that selecting the reference state for the determination of the probe signal SS does not force the implementation of step 3E2 of transmitting the probe signal SS, step 3E3 of receiving the response of the electrochemical system BAT, and step 3E4 of analyzing the response when the electrochemical system BAT is in this reference state. Conversely, these steps can also be carried out during operation between two instants when the electrochemical system BAT is in this reference state. Executed can occur. Such Execution During this period, the variation of the energy transmitted by the probe signal SS and the variation of the power spectral density observed in the response RE of the electrochemical system BAT related to the expected response RE change reversibly, and except for the case of malfunction, follow similar changes in each cycle and approach the reference value when the electrochemical system BAT approaches the reference state again (when the aging degradation that induces a slight deviation shown below is eliminated). Therefore, using the reference state makes it possible to examine that this reversible change in the response to the probe signal SS has occurred.

[0067] It is only possible to inspect the state of the electrochemical system BAT when the electrochemical system BAT is in the reference state from the same alternative means. Naturally, it becomes impossible to observe the above-described changes. However, this embodiment includes step 3E2 of transmitting the probe signal SS, step 3E3 of receiving the response of the electrochemical system BAT, and step 3E4 of analyzing the response Execution It can be adapted to situations where it is desired to reduce the number of Execution , or situations where changes in responses outside the range of the reference state are of little interest. For this reason, in one embodiment, step 3E2 of transmitting the probe signal SS, step 3E3 of receiving the response of the electrochemical system BAT, and step 3E4 of analyzing the response are each time the electrochemical system BAT reaches the reference state used to determine the probe signal SS Execution is carried out. If the electrochemical system BAT is in the reference state at each step of measuring the response RE, it becomes easy to compare the measured response with the expected response.

[0068] As described above, it is interesting to proceed with the statistical analysis of the response RE of the electrochemical system BAT to the probe signal SS. This approach particularly enables the automation of the determination of one or more thresholds or tolerances corresponding to malfunctions of the electrochemical system BAT. Also, by adding measurements that supply statistical values of the response RE during the operation of the electrochemical system BAT, it becomes possible to automate the update of these thresholds. For this reason, in one embodiment shown in [Figure 10], step 3E4 of analyzing the response is: - Sub-step 3E41 of determining the spectral density of the response RE to the probe signal SS; - Sub-step 3E42 of storing the spectral density of the response RE to the probe signal SS; - Sub-step 3E43 of comparing the determined spectral density with the statistical value of the response RE, wherein the statistical value is determined from the spectral density stored in the preceding Execution sub-step 3E42 of storing the spectral density of the response RE to the probe signal SS, sub-step 3E43; Sub-step 3E44 for detecting a fault in the electrochemical system BAT when the difference between the spectral density determined during decision-making sub-step 3E41 and the statistical value of the response is greater than the re-determined value includes.

[0069] In one embodiment, a fault in the electrochemical system BAT is detected when the spectral density of the response RE is more than 3σ away from the statistical value of the response for at least one frequency during sub-step 3E44 for detecting a fault in the electrochemical system.

[0070] In an alternative embodiment, a fault in the electrochemical system BAT is detected when the spectral density of the response RE is more than 3σ away from the statistical value of the response for a plurality of frequencies during sub-step 3E44 for detecting a fault in the electrochemical system, and the number of frequencies constituting the plurality of frequencies is selected according to the desired sensitivity. It may also be useful to note that this statistical method can also be used within the framework of the method 200 for inspecting the compliance of the electrochemical system BAT according to the second aspect of the present invention, and the statistical values used at that time are those obtained from a plurality of calibrated electrochemical systems BAT.

[0071] Due to the variation of the response RE over time, it becomes possible to determine whether the materials that make up the electrochemical system BAT are subject to reversible variations (repeatable changes for each charge-discharge cycle, temperature effects) within a pre-defined limit range, or slow continuous deviations (aging degradation of the battery and equipment assembly), and furthermore, sudden variations that should be signs of malfunction and exceed the pre-defined limits. Therefore, it is interesting to consider these variations.

[0072] Therefore, in one embodiment, the rate of change of the response RE of the electrochemical system BAT to the probe signal SS is also considered. More specifically, during step 3E4 of analyzing the response, when the rate of change of the response (defined as the difference between the last two measured responses RE divided by the time separating these two measurements) deviates beyond a predefined threshold, a malfunction of the electrochemical system BAT is detected. The predefined threshold can be adjusted according to the rate of change considered normal and / or the statistical value of the rate of change configured simultaneously with the statistical value of the response. Preferably, this verification of the change is performed for each frequency. In other words, the variation of the spectral density is evaluated for each frequency so as to obtain as many variation values as possible for the frequencies considered. In this case, when at least one frequency is associated with a variation greater than a predetermined threshold, or when the number of predefined frequencies is associated with a variation greater than a predefined threshold, a malfunction can be observed. In the second case, the number of frequencies considered can depend on the desired sensitivity of the detection of the malfunction. The threshold can vary according to the frequencies considered or can be the same for all frequencies.

[0073] In one embodiment, when a failure is detected, the method according to the third aspect of the invention includes the step of sending a signal to the management system in charge of the electrochemical system so that the electrochemical system can apply a corrective measure.

[0074] Monitoring of aging degradation of electrochemical system It may be interesting to use the probe signal SS not only to identify malfunctions but also to monitor the aging degradation of the electrochemical system BAT. In fact, for the same system BAT, if the probe signal SS is determined at two instants separated in time in a given reference state, the correction factor associated with the probe signal SS determined at the first instant will be different from the correction factor associated with the probe signal SS determined at the second instant, for a given expected response RE. This change in the correction factor generally indicates the change over time of the electrochemical system BAT, induced by aging degradation.

[0075] To utilize this, in one embodiment shown in [Figure 11], the method 300 according to the third aspect of the present invention includes, after step 3E4 of analyzing the response to detect a malfunction of the electrochemical system, step 3E5 of determining a new probe signal SS using the method 100 according to the first aspect of the present invention with the correction factor stored. Additionally, in this embodiment, the method 300 according to the third aspect of the present invention also includes step 3E6 of analyzing the change in the correction factor to detect possible malfunctions. In one embodiment, step 3E5 of determining a new probe signal SS is performed only when the electrochemical system BAT is in the reference state. Execution In one embodiment, an indicator of the aging degradation of the electrochemical system (as well as / or the means for generating and / or acquiring the signal) is determined from the change in the correction factor.

[0076] More generally, the change in the correction factor can be used to characterize a number of phenomena. For example, to determine the rate of the mechanism of aging degradation of the material and even of the electrochemical system BAT, it is possible to consider the rate of change of these correction factors (average rate, maximum rate for all frequencies of the signal, and / or rate of one or more correction factors associated with one or more specific frequencies).

[0077] It is also possible to consider the acceleration of the changes in these correction factors. For example, the time-wise acceleration of the rate of change of these correction factors may be due to the degradation of materials linked to strong transient stresses in the electrochemical system BAT (such as operation at high power for rapid charging or discharging, operation at high temperature, or charging at low temperature).

[0078] Generally, by delving deeply into the analysis of the rate of change of the correction factors, it becomes possible to identify the optimal operating conditions and the operating conditions to be avoided for the electrochemical system BAT, and objectively define the optimal operating range (range of state of charge, temperature, and maximum power) of the electrochemical system BAT. There is no reason for the optimal operating range of the electrochemical system BAT to be constant throughout the entire service life of the electrochemical system BAT: for example, it should be noted that certain operating conditions that cause strong stress can be accepted without major problems on a new battery, but not necessarily on a battery at the end of its life.

[0079] Device for executing the present invention A fourth aspect of the present invention relates to a device comprising means configured to perform the method according to the first, second, or third aspect of the present invention. Execution In one embodiment, the device comprises means PZ1 for generating a calibration signal SC or a probe signal SS within the electrochemical system BAT. In one embodiment, these means for generating can be removably arranged on the electrochemical system. In one embodiment, the device comprises means PZ2 for receiving the response RE of the electrochemical system to the calibration signal SC or the probe signal SS. In one embodiment, these means for receiving can be removably arranged on the electrochemical system. In one embodiment, the device comprises means for calculating and a memory, and the memory stores the method according to the first, second, or third aspect of the present invention. Executionconfigured to store the instructions required therefor. Further, the means for calculating is configured to access this memory and execute the instructions. The means for calculating is configured to receive data collected by means PZ2 for receiving the response RE of the electrochemical system BAT by controlling means PZ1 for generating the probe signal SS or for calibrating the calibration signal SC. In one embodiment, the device is a management system of the electrochemical system BAT, for example a system for managing a battery.

Claims

1. A method for detecting a fault in an electrochemical system, the method comprising: - At a first instant, - Transmitting a first signal called a calibration signal comprising a train of waves of a plurality of frequencies so as to induce a response of the electrochemical system, wherein the spectral density associated with each frequency is the same; - Receiving the response of the electrochemical system to the calibration signal; - Determining a signal attenuation coefficient for each frequency of the calibration signal based on the received response; - Determining a correction coefficient for each attenuation coefficient according to the attenuation coefficient so as to associate a correction coefficient with each frequency of the calibration signal; - Determining a probe signal, wherein the probe signal is obtained by multiplying the spectral density associated with each frequency of the calibration signal by the correction coefficient corresponding to that frequency; - Transmitting the probe signal determined above; - Receiving the response of the electrochemical system to the probe signal; - Analyzing the response so as to detect a fault in the electrochemical system; comprising - At a second instant, - Determining a new probe signal by re-transmitting the calibration signal, receiving the response of the electrochemical system to the calibration signal, determining a signal attenuation coefficient for each frequency of the calibration signal, determining a correction coefficient for each attenuation coefficient, and determining a probe signal, wherein the correction coefficients are stored; - Analyzing the change in the correction coefficient so as to detect a fault in the electrochemical system or an aging change of an indicator based on the difference between the correction coefficient determined at the first instant and the correction coefficient determined at the second instant; A method comprising.

2. The method according to claim 1, wherein during the step of determining the probe signal, the probe signal is determined while the electrochemical system is in a reference state.

3. The method according to claim 2, wherein the steps of transmitting the probe signal, receiving the response of the electrochemical system, and analyzing the response are performed each time the electrochemical system reaches the reference state used to determine the probe signal during the step of determining the probe signal.

4. The step of analyzing the response comprises - a sub-step of determining the spectral density of the response to the probe signal; - a sub-step of storing the spectral density of the response to the probe signal; - a sub-step of comparing the determined spectral density with the statistical value of the response, wherein the statistical value of the response is determined from the spectral density stored during a previous implementation of the sub-step of storing the spectral density of the response to the probe signal; - a sub-step of detecting a fault in the electrochemical system when the difference between the spectral density determined during the determining sub-step and the statistical value of the response is greater than a predetermined value; The method according to claim 1, comprising. **Claim 5** The method according to claim 1, wherein the spectral density associated with each frequency in the calibration signal is selected to induce a linear response of the electrochemical system. **Claim 6** The method according to claim 1, wherein the duration of the probe signal is long enough to establish a steady state in the response of the electrochemical system. **Claim 7** The method according to claim 1, wherein frequencies associated with a damping factor greater than a predetermined threshold are not considered in the determination of the probe signal. **Claim 8** The method according to claim 1, wherein during the step of transmitting the first signal, the calibration signal is transmitted while the electrochemical system is in a reference state. **Claim 9** A method for inspecting an electrochemical system to be inspected against a reference electrochemical system, comprising: - determining a probe signal using the method according to claim 1 executed on the reference electrochemical system; For each calibration electrochemical system of a plurality of calibration electrochemical systems, - transmitting the probe signal determined above; - receiving the response of the calibration electrochemical system to the probe signal, whereby the statistical value of the response of the calibration system is obtained, The method also includes - transmitting a probe signal within the electrochemical system to be inspected; - receiving the response of the electrochemical system to be inspected to the probe signal; - comparing the response of the electrochemical system to be inspected with the statistical value of the response of the calibration electrochemical system so as to detect a fault in the electrochemical system to be inspected. A method comprising. **Claim 10** The method according to claim 9, wherein the probe signal is re-determined at regular intervals or in response to a request from the user.

11. A device for determining a probe signal, for inspecting an electrochemical system, or for detecting a fault in an electrochemical system, comprising a system configured to perform the method according to claim 1.

12. A computer program comprising instructions for causing the device according to claim 11 to perform the method according to claim 1.

13. A computer-readable storage medium having recorded thereon a computer program comprising machine-executable instructions for performing the method according to claim 1.

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