Method for recovering capacity of an electrochemical energy storage device, and corresponding device and computer program

Abstract

Disclosed is a method for recovering capacity of an electrochemical energy storage device, comprising alternating steps of: a. fully charging (S1) the device to a maximum charge voltage (Umax); b. relaxing (S2) the device for a period TREL; the alternating steps being repeated during a period of unavailability TIND of the electrochemical device and carried out at a cycling current CCyc less than or equal to the maximum current supported by the electrochemical device in normal operation.

Description

Description Title: Process for recovering capacity from an electrochemical energy storage device, corresponding device and computer program Technical field [1] This disclosure relates to the field of energy storage in electrochemical devices such as batteries. More specifically, this disclosure concerns extending the lifespan of such energy storage devices. [2] It finds applications for all devices and systems in which such electrochemical energy storage devices are found, such as rechargeable batteries, and in particular, for example, a lithium-ion battery, a solid-state lithium battery, a sodium-ion battery, a solid-state sodium battery, etc. [3] The present disclosure aims in particular to increase the lifespan of such storage systems, in particular systems requiring the cycling of batteries over a reduced state of charge (or SOC) range (this is the case for example of storage systems used to operate frequency regulation on an electrical network), or at high current (this is the case for example of storage systems requiring fast charging). Previous technique [4] The operation of a rechargeable electrochemical energy storage device relies on a set of reversible electrochemical reactions at the cathode (positive electrode) and the anode (negative electrode). To achieve high reversibility during battery charge / discharge cycles, an "intercalation" reaction is used, which allows target ions (e.g., Li ions) to interact with the anode. + or Na +) to move in the "ionic" state between the cathode and the anode during the operation of the device, with a low rate of parasitic reaction. [5] More specifically, taking the example of the lithium ion, its small size allows it to reversibly intercalate into host materials such as those with a lamellar structure (e.g., graphite or LiMC, where M is chosen from Mn, Co, and Ni), a spinel structure (e.g., LiMn2O4), or an olivine structure (LiFePCk), filling vacant interstitial sites while preserving their structure. The intercalation of the Li ion + , and then its extraction, form a reversible "breathing movement" of the structure. Thus, in the case of a lithium-ion battery being charged, the Li ions +Electrons are released from the cathode (disintercalation or disinsertion reaction) and insert themselves at the anode (intercalation or insertion reaction). During discharge, the opposite reaction occurs at the cathode (intercalation) and at the anode (disintercalation). This reaction in the ionic state ensures its reversibility and the proper functioning of the rechargeable electrochemical device. [6] Certain irreversible parasitic reactions, for example due to electrolyte consumption or localized deposit of metallic lithium on the anode, can nevertheless occur and lead to a decrease in the battery's charging capacity. Degradation, and therefore loss of capacity electrochemical storage systems, is generally slow and linear up to 80-70% of state of health (or SOH for "State Of Health") (capacity loss of 20 to 30%). [7] Under certain operating conditions, this capacity loss is sometimes accelerated by the appearance of inhomogeneities within the electrochemical cell. This is particularly true for systems operating within narrow SOC ranges (typically a 40-60% SOC range), especially if they are composed of Li-ion LFP / Graphite cells (where LFP stands for Lithium Iron Phosphate, or LiFePO4). This includes energy storage systems used for load frequency control (LFC), which must be able to switch rapidly between charging and discharging, with timescales of 30 seconds to 30 minutes at relatively high rates (e.g., 2C). Consequently, the resulting operating SOC range is relatively narrow due to the rapid polarity reversal. [8] Indeed, when the cell remains constantly at an average charge state close to 50%, the cathode potential curve in LFP is almost flat, with two phases coexisting for a large part of the charge or discharge. Therefore, no potential difference forces the homogenization of lithium ions on the electrode surface. The appearance of local inhomogeneity will thus increase over time and lead to the creation of areas rich and poor in Li ions. + These inhomogeneities will then greatly accelerate the loss of capacity of the device (capacity based on areas with lower Li-ion concentrations). + ). [9] A similar phenomenon is also observed for electrochemical cells cycling at high current (typically a C-rate greater than 1 C). Indeed, since not all ions have time to move from one electrode to the other, the appearance of a slight inhomogeneity also increases over the course of the cycles.

[0010] However, it has been observed that these inhomogeneities are reversible.

[0011] It has been observed in particular that it is possible to re-homogenize the distribution of lithium ions by placing the electrochemical cell at rest with a significant pause time (of several months for example), which allows time for the lithium ions to re-homogenize, or by carrying out complete charge / discharge cycles which allows each electrode to be alternately emptied of all its ions and to "reset" the distribution of ions, or by carrying out low current cycles for a high current cycling device.

[0012] These mechanisms of appearance of inhomogeneities within the electrochemical cell, and of recovery of cell capacity by re-homogenizing the distribution of lithium ions, have notably been studied by Kobayashi et al. in the article "Unexpected capacity fade and recovery mechanism of LiFePO4 / graphite cells for grid operation", Journal of Power Sources, 449, 227502 (2020).

[0013] In this article, Kobayashi et al. study more specifically two protocols allowing capacity recovery for batteries in which such inhomogeneities have appeared due to non-uniform ionic conduction of Lithium ions between the anode and the cathode.

[0014] The first protocol involves placing the battery at complete rest, in a state of charge of 20%, for a long period of approximately 40 days.

[0015] A second protocol, allowing for greater capacity recovery, relies on cycling through the full SOC range (0%-100%), over a series of 450 cycles, with 30-minute breaks between successive cycles, for a duration of 40 days. This series of total charges and discharges ("full SOC >>"), designed to homogenize ion diffusion within the cell, resulted in the greatest capacity recovery achieved, namely 20% for a 40-day protocol.

[0016] While these results are promising, all the protocols studied have the drawback of requiring prolonged downtime of the electrochemical storage devices. Thus, while the observed capacity recovery is valuable in that it increases the lifespan of the storage devices, their unavailability over a wide period of time results in significant financial losses for the operators of such storage devices.

[0017] Therefore, there is a need for a capacity recovery technique for electrochemical energy storage devices that does not have these disadvantages of the prior art, and improves the situation. Summary

[0018] This disclosure addresses this need by proposing a method for recovering the capacity of an electrochemical energy storage device, comprising alternating steps of: fully charging the device to a maximum charging voltage; relaxing the device for a relaxation time, TREL; this alternation being repeated for an unavailability time, TIND, of the electrochemical device and carried out at a cycling current, CCyc, less than or equal to the maximum current supported by the electrochemical device. Such a maximum current corresponds, for example, to the current specified by the manufacturer of the electrochemical device in its datasheet.

[0019] This disclosure is based on a completely new and inventive approach to extending the lifespan of rechargeable batteries. It enables a capacity boost in the storage system, and therefore an increase in its lifespan, with a reduced downtime compared to prior art solutions. This is achieved through an advantageous process based on alternating periods of full charging and battery relaxation, the parameters of which are optimized to achieve a satisfactory compromise between capacity gain and downtime of the electrochemical storage device. Under experimental conditions, a 15% capacity gain was thus achieved in a reduced time of just eight days.

[0020] Unlike prior art solutions, such a capacity recovery process advantageously exploits the combined effect of pause and full charge up to a 100% SOC, and eliminates the need for a long discharge phase and long charging times (the The battery remains essentially in a charged state during the relaxation period, which significantly reduces the downtime (TIND) of the electrochemical energy storage device for its operator. This is because relaxation eliminates the concentration gradients generated by the current flow and induces only a slight decrease in cell voltage, primarily due to diffusion.

[0021] According to one aspect, such a capacity recovery process includes a choice of the relaxation time TREL and the cycling current CCyc based on a maximum unavailability time desired by an electrochemical device manager.

[0022] Indeed, by varying the charging current and relaxation time, it is possible to vary the downtime for a given target capacity recovery. Thus, by reducing the relaxation time TREL, for example, from 1 hour to 30 minutes, the efficiency of the capacity recovery is slightly reduced, but the downtime TIND of the electrochemical device is also considerably reduced, since the capacity recovery protocol can be completed in only 100 hours, or about 4 days, instead of 200 hours (or about 8 days).

[0023] Indeed, according to one aspect, for an electrochemical device whose maximum possible current indicated by the manufacturer is equal to 1 C, the cycling current CCyc during the alternation is equal to C / 2, the relaxation time TREL is equal to one hour and the unavailability time TIND corresponds to the duration of fifty complete equivalent cycles, FEC, of ​​the electrochemical device.

[0024] Such a duration, equivalent to 50 FEC cycles, corresponds to approximately 200 hours, or 8 days. The results obtained demonstrate the high effectiveness of the protocol based on these parameters, with a capacity gain of 15% achieved.

[0025] More generally, according to one aspect, for an electrochemical device whose maximum possible current indicated by the manufacturer is equal to 1 C, the cycling current CCyc during the alternation is preferably between C / 2 and C / 4.

[0026] In another respect, such a capacity recovery process is implemented when the capacity of the electrochemical device decreases by a value exceeding a predetermined threshold. For example, such a predetermined threshold corresponds to a capacity loss of the electrochemical device greater than or equal to 5%, preferably greater than or equal to 10%.

[0027] Thus, such a capacity recovery process can advantageously be applied at regular intervals throughout the lifespan of the electrochemical storage device, for example, each time it has lost 10% of its capacity. By adjusting the frequency of implementation of such a capacity recovery process, it is also possible to adjust the downtime of the electrochemical device.

[0028] Alternatively, or in addition, such a capacity recovery process is implemented at regular time intervals during the lifetime of the storage device, regardless of the measured capacity of the device.

[0029] According to another aspect, such a capacity recovery process is implemented during a period of scheduled maintenance of the electrochemical device.

[0030] This significantly reduces the downtime of the electrochemical device. Furthermore, during such maintenance periods, the device operator typically performs a complete cycle, after which they measure the residual capacity of the electrochemical device. By comparing this to the cell's nominal capacity, they can deduce the value of the cell's capacity loss and then decide, based on this loss, whether or not to initiate a capacity recovery process for the electrochemical device.

[0031] According to another aspect, such an electrochemical device is integrated into a stationary storage system, for example configured to perform frequency regulation of an electrical distribution network, or into a storage system configured to cycle at a high C-rate, preferably greater than 1 C.

[0032] Indeed, these storage systems are particularly prone to reversible inhomogeneities in ion flow within the cell, and are therefore particularly well-suited to capacity recovery using the capacity recovery process described in this disclosure. Rapid capacity loss is generally observed in these storage systems after a certain number of cycles, meaning a certain duration of operation under these conditions of shallow depth of discharge (or DOD, which is the ratio, expressed as a percentage, between the discharged capacity and the battery's nominal capacity) or high current.

[0033] In yet another respect, the electrochemical device is a lithium-ion battery comprising a graphite anode and a LiFePO4 cathode. The experimental results obtained for such an electrochemical device have indeed been particularly interesting in terms of capacity recovery. The process described in this disclosure, however, is applicable to all battery technologies.

[0034] The features described in the preceding paragraphs may optionally be implemented independently of each other or in combination with each other.

[0035] This disclosure also relates to a capacity recovery device for an electrochemical energy storage device, comprising at least one processing circuit connected to the electrochemical device for the implementation of the process as described above.

[0036] This disclosure further relates to a computer program containing instructions for the implementation of all or part of a process as defined herein when that program is executed by a processing circuit.

[0037] It also relates to a non-transient, computer-readable recording medium on which such a program is recorded. Such a recording medium can be any entity or device capable of storing the program. For example, the medium may include a storage means, such as a ROM, for example a CD-ROM or a circuit ROM. microelectronics, or a magnetic recording device, for example a USB key or a hard drive.

[0038] On the other hand, such a recording medium can be a transmissible medium such as an electrical or optical signal, which can be transmitted via an electrical or optical cable, by radio, or by other means, so that the computer program it contains can be executed remotely. The program according to the invention can, in particular, be uploaded to a network, for example, the Internet.

[0039] Alternatively, the recording medium may be an integrated circuit in which the program is incorporated, the circuit being adapted to execute or to be used in the execution of the aforementioned capacity recovery process.

[0040] The capacity recovery device, computer program and recording medium mentioned above have at least the same characteristics and advantages as the capacity recovery process described above. Brief description of the drawings

[0041] Other features, details and advantages will become apparent upon reading the detailed description below, and upon analyzing the attached drawings, in which: Fig. 1

[0042] [Fig. 1] illustrates a pattern of alternating periods of charging and relaxing an electrochemical energy storage device according to an embodiment of a process for recovering the capacity of this device. Fig. 2

[0043] [Fig. 2] presents in the form of an organizational chart the different stages of the capacity recovery process according to one embodiment. Fig. 3

[0044] [Fig. 3] presents in schematic form the structure of a capacity recovery device according to one embodiment. Description of the implementation methods

[0045] The general principle of this disclosure is based on alternating full charge (maximum voltage indicated in the device's datasheet) and relaxation (pause) cycles applied to an electrochemical energy storage device. This cycle restores the storage device's capacity, thereby increasing its lifespan with reduced downtime. This method, which can be applied throughout the battery's life to limit degradation, is optimized to maximize capacity recovery while minimizing device downtime.

[0046] In the following, the terms battery, cell, electrochemical energy storage device or electrochemical device will be used interchangeably to refer to a rechargeable device subject to reversible capacity loss, and on which the capacity recovery process presented here can be advantageously applied.

[0047] During its operation, also known as cycling (referring to the successive cycles of total or partial charging and discharging of the battery), the battery's capacity decreases over time. Part of this capacity loss is irreversible and linked to the aging of its components, induced by certain parasitic reactions or various degradation mechanisms. Another part of this capacity loss, however, is reversible, as it results from the appearance of inhomogeneities within the electrodes of the electrochemical cell.

[0048] This reversible portion of capacity loss is particularly observable for rechargeable batteries composed of LFP on the cathode side, and it increases for energy storage systems operating on reduced SOC ranges, between 40% and 60% for example.

[0049] This is typically the case with stationary storage systems, used for example to complement renewable energy sources, which are configured to maintain the electrical grid frequency within an acceptable operating range. Such systems are also called frequency regulation systems.

[0050] This is also the case for storage systems cycling at a high C-rate, or high charging current, greater than 1 C for example. Recall that the discharge rate or C-rate, expressed as a multiple of C, corresponds to the ratio of the applied current (i.e., the discharge rate) to the battery capacity C: i C — rate = — C

[0051] The capacity recovery protocol proposed in one embodiment eliminates these inhomogeneities, thereby restoring capacity to the storage device or system. It can be applied at regular intervals (for example, each time the system loses 10% of its capacity or during each scheduled maintenance) throughout its lifespan.

[0052] Reference is now made to Figure 1, which shows the general pattern of alternating charging and relaxation periods according to one embodiment. The curve in Figure 1 represents the voltage across the battery terminals, expressed in Volts (V), as a function of time t.

[0053] In one embodiment, the capacity recovery process for an electrochemical energy storage device consists of alternating periods of full charging S1 (CCyc) at the charging current CCyc, allowing the battery to reach a state of charge SOC=100%, and periods of rest or relaxation S2 (TREL), during which the battery is left at rest for a duration of relaxation TREL. This alternation of charging S1 (CCyc) and relaxation S2 (TREL) stages is repeated for a time TIND, which corresponds to a period of battery unavailability for effective operation.

[0054] The S1 (CCyc) charge ends when the voltage across the storage device reaches a value Umax corresponding to the maximum operating voltage of the device, which translates to a full charge state SOC=100%.

[0055] Depending on the battery's initial state of charge, the first full charge period S1 (CCyc) may be longer than subsequent charging stages. This is because, during the relaxation periods S2, the battery is left at rest without being subjected to any charging or discharging: the voltage across its terminals therefore decreases only slightly. The return to a full state of charge SOC=100% during the next S1 (CCyc) charging period is thus faster than during the first full charge period.

[0056] The charge / relax cycle illustrated in Figure 1 was experimentally applied to a 200 Ah class (nominal battery capacity) prismatic LFP / Graphite cell with a manufacturer's specified maximum current of 1 C, and which cycled at room temperature according to a frequency regulation profile. Such a cell typically operates within a state of charge (SOC) range of 40% to 60%, which leads to inhomogeneities within the cell.

[0057] The capacity recovery protocol illustrated in Figure 1 was applied to it, at room temperature, with the following parameters: - TREL=1 h; - CCyc=C / 2 ; - TiND=200h, or approximately 8 days, which corresponds to the duration of 50 full cycles (or 50 FEC for "Full Equivalent Cycles"). A cycle refers to the combination of a discharge period and a charge period of the battery.

[0058] The table below presents the results obtained in terms of capacity recovery for this cell after application of such a protocol. These results are measured by performing a charge and discharge cycle of the battery, before and after application of the capacity recovery protocol, with a charge / discharge current of C / 5.

[0059] [Table 1]

[60] As can be seen from Table 1, the gain obtained at the end of the charge / discharge cycle between the discharged capacity before application of the capacity recovery protocol and after application of the protocol amounts to 18.25%. In this embodiment, the capacity recovery protocol therefore makes it possible, in just 8 days, to achieve a capacity recovery of more than 15%.

[0061] Such a capacity recovery protocol is therefore particularly optimized, in that, compared with prior art methods, the TIND downtime (i.e. the lost time, and therefore the financial loss for the storage system manager) is minimal, while the capacity recovery is significant.

[0062] Depending on the use case, the parameters (cycling current, pause time, temperature, etc.) can be adjusted according to the cell type (energy vs. power) or the demand (frequency adjustment, peak shaving, etc.). It is also possible to vary the downtime by adjusting the charging current, the relaxation time, and the duration and frequency of the proposed method.

[0063] For the cell model considered, it is therefore possible to reduce the TREL relaxation time from 1 hour to 30 minutes, which will slightly reduce the efficiency of the capacity recovery but will allow the protocol to be carried out in only 100 hours, or about 4 days.

[0064] Similarly, for the cell used in the construction of Table 1, doubling the cycling current CCyc can approximately halve the cell's downtime TIND. Conversely, the charging current CCyc during the charging stage S1 could be reduced to C / 3, which would increase capacity recovery but would also increase the cell's downtime TIND. For the specific cell model used in this embodiment, a charging current of C / 2 was found to be optimal, as it allowed for significant capacity recovery within a downtime acceptable to the operator, thus representing a favorable compromise.

[0065] It is also possible to adjust the frequency of application of this recovery protocol over the lifetime of a battery.

[0066] For stationary applications (network service type), the operator generally performs a performance check of its stationary storage systems once a year ("check-up >>), during which it measures the capacity of these storage systems, and can therefore assess the loss of capacity compared to the nominal capacity of the system.

[0067] In an advantageous embodiment, the capacity recovery protocol can be applied after this check-up: depending on the evolution of the capacity measured at each check-up, this could be, for example, twice a year, once a year, or once every two years...

[0068] For example, the capacity recovery protocol can be applied following this check-up if the operator measures a capacity loss greater than 10%.

[0069] The following is presented in relation to figure 2, an organizational chart of the steps implemented by the operator in such a case.

[0070] During a step referenced E0, the operator of the stationary storage system evaluates the capacity C of a battery, and the capacity loss relative to the nominal capacity. This measurement MES(C) is for example carried out following a battery check-up phase, as part of a scheduled maintenance operation.

[0071] During a step referenced E1, this measured capacity C is compared to a CTH capacity threshold below which the operator does not wish to go (alternatively, the capacity loss relative to the nominal capacity is expressed as a percentage, and this percentage is compared to a maximum loss tolerated by the operator, or to a threshold loss beyond which it seems necessary to implement a capacity recovery protocol for this battery).

[0072] If the measured capacity C is greater than the capacity threshold CTH, the battery can be put back into service, and its maintenance and unavailability phase ends (step S4).

[0073] On the other hand, if the capacity loss is greater than 5 or 10%, for example, the operator can choose to launch the capacity recovery protocol, which is initialized during an INIT S0 step. Depending on the type of battery and the type of use to which it is put, the operator chooses the appropriate parameters of this capacity recovery protocol, in particular the value of the cycling current CCyc and the duration of the relaxation time TREL, so that they are compatible with the maximum unavailability time TIND of the battery to which the operator can agree.

[0074] The battery then undergoes a charging phase S1 at a charging current CCyc, until it reaches a state of charge SOC=100%.

[0075] It is then left at rest S2 for a duration of relaxation TREL.

[0076] At the end of each S1 + S2 phase alternation, a check is performed during step S3 to verify whether the maximum unavailability time (TIND) set by the operator has been reached. If not, the alternation of the full charge phase (S1) and the relaxation phase (S2) continues. If so, the capacity recovery protocol is complete, and the battery can be put back into service by the operator (step S4 FINJND).

[0077] Optionally, before putting the battery back into service, the operator can carry out a new measurement of its capacity (step E0 MES(C)), to verify the effectiveness of the capacity recovery protocol that he has just applied.

[0078] Similarly, it should be noted that steps E0 and E1 are optional (dotted lines). Indeed, the operator can choose to implement the capacity recovery protocol at regular time intervals, for example once a year, regardless of any potential battery capacity loss.

[0079] Figure 3 schematically illustrates the structure of a DIS (Dispositif d'Insertion) device for capacity recovery from a BATT (Bâtiment d'Électrochemical) electrochemical energy storage device. Such a DIS device includes a processing circuit connected to the BATT electrochemical device for implementing the capacity recovery process described above.

[0080] Referring to Figure 3, this processing circuit may include: - an input interface IN for signals from the electrochemical device BATT, during its charging or discharging, these signals including the voltage V (in volts) across the device terminals electrochemical BATT and charge / discharge Q (in ampere-hours), - a MEM memory capable of storing, at least temporarily, voltage and charge / discharge values, as well as instruction data for a computer program to implement the above process. The MEM memory can be of the ROM (Read Only Memory) or RAM (Random Access Memory) type, or even Flash. - a PROC processor capable of cooperating with the MEM memory and, in particular, of reading the instructions stored in memory to execute the steps necessary for implementing the process defined above. Thus, the PROC processor can calculate the battery's state of charge (SOC) or control the measurement of capacity (C). And - an output interface OUT cooperating with the processor PROC to possibly deliver the result of a measurement of the battery's capacity C, intended to be displayed on a human / machine interface (display on a screen or broadcasting an audio signal), and to send CMD commands to execute the alternation of the full charge S1 and relaxation S2 phases of the battery BATT.

[0081] Figure 3 illustrates only one particular way, among several possible ways, of implementing a capacity recovery device for an electrochemical energy storage device, so that it performs the steps of the process detailed above, in relation to Figures 1 and 2 (in any one of the different embodiments, or in a combination thereof). Indeed, these steps can be performed interchangeably on a reprogrammable computing machine (a PC, a DSP processor, or a microcontroller) executing a program comprising a sequence of instructions, or on a dedicated computing machine (for example, an array of logic gates such as an FPGA or an ASIC, or any other hardware module).

[0082] The battery capacity recovery protocol described above can be used by all managers of electrochemical storage systems that may experience rapid, reversible capacity loss. This is particularly relevant for energy companies operating storage systems for frequency regulation or for storing power generated from intermittent energy sources. The procedure can be carried out during scheduled maintenance periods for the devices.

[0083] This protocol can also be useful to any battery user subjected to rapid charging.

[0084] Various protocols were carried out in the laboratory with different parameter values ​​(relaxation times, charging currents, unavailability periods, etc.) on different types of batteries and electrochemical cells that had undergone reversible capacity loss. The results show that the presented procedure is particularly effective in increasing the lifespan of electrochemical storage systems. This procedure can be easily adapted for industrial use. List of documents cited Non-patent literature

[0085] For the record, the following non-patent item is cited: - Kobayashi et al. “Unexpected capacity fade and recovery mechanism of LiFePO4 / graphite cells for grid operation”, Journal of Power Sources, 449, 227502 (2020).

Claims

Claims

1. Method for recovering the capacity of an electrochemical energy storage device, comprising an alternation of steps of: a. complete charging (S1) of said device at a maximum charging voltage (Umax); b. relaxation (S2) of said device for a relaxation duration, TREL; said alternation being repeated for an unavailability duration, TIND, of said electrochemical device and carried out at a cycling current, CCyc, less than or equal to the maximum current supported by said electrochemical device.

2. A capacity recovery method according to claim 1, further comprising a choice of said relaxation time TREL and said cycling current CCyc as a function of a maximum unavailability time desired by a manager of said electrochemical device.

3. A method of recovering capacity according to any one of claims 1 and 2, characterized in that, for an electrochemical device whose maximum supported current is equal to 1 C, said cycling current CCyc during said alternation is substantially between C / 2 and C / 4.

4. Capacity recovery method according to any one of claims 1 to 3, characterized in that, for an electrochemical device whose maximum supported current is equal to 1 C, said cycling current CCyc during said alternation is equal to C / 2, said relaxation time TREL is equal to one hour and said unavailability time TIND corresponds to the duration of fifty complete equivalent cycles, FEC, of ​​said electrochemical device.

5. A method of recovering capacity according to any one of claims 1 to 4, characterized in that it is implemented when the capacity of said electrochemical device decreases by a value greater than a determined threshold.

6. Capacity recovery method according to claim 5, characterized in that said determined threshold corresponds to a capacity loss greater than or equal to 5% of said electrochemical device, preferably greater than or equal to 10%.

7. A method of recovering capacity according to any one of claims 1 to 6, characterized in that it is implemented during a scheduled maintenance period of said electrochemical device.

8. A capacity recovery method according to any one of claims 1 to 7, characterized in that said electrochemical device is integrated into a stationary storage system configured to carry out frequency regulation of an electrical distribution network.

9. Capacity recovery method according to any one of claims 1 to 7, characterized in that said electrochemical device is integrated into a storage system configured to cycle at a high C-rate, preferably greater than 1 C.

10. A capacity recovery method according to any one of claims 1 to 9, characterized in that said electrochemical device is a Lithium-ion battery comprising a graphite anode and a cathode composed of LiFePCk.

11. Device for recovering the capacity of an electrochemical energy storage device, comprising at least one processing circuit connected to the electrochemical device for implementing the method according to one of the preceding claims.

12. Computer program comprising instructions for implementing the method according to one of claims 1 to 10, when said instructions are executed by a processing circuit.

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