How to Recondition Nickel Metal Hydride Battery Cells

Abstract

The present invention relates to a method for reconditioning a battery module (1), which includes two or more battery cells (2) and has a casing (4) that contains the battery cells and encloses a common gas space (5). The method includes the steps of obtaining data regarding the number of cells in the battery module and the voltages on the battery cells, measuring the internal resistance (R i ), determining (104) an amount of oxygen to be charged into the battery module based on the indication parameters and data relating to the battery module; and determining whether the voltage indication of at least one of the battery cells is greater than or equal to a voltage indication threshold (U t0 -U t1 ), and charging the battery module with the charge of oxygen to reduce the indicator parameter to a level below a first threshold (107).

Description

[Technical Field]

[0001] The present invention relates generally to the field of reconditioning battery cells, particularly metal hydride battery cells. The method relates to battery modules that add oxygen gas and, optionally, hydrogen gas to improve performance. Furthermore, the present invention relates specifically to the field of extending the life of battery modules. [Background technology]

[0002] Nickel-metal hydride (NiMH) batteries have a long cycle life and rapid charge / discharge capabilities. During charging and discharging, hydrogen is transported between the electrodes in the form of water molecules, causing the electrodes to interact with each other via the alkaline electrolyte. During discharging, hydrogen is released from the negative electrode and moves to the positive electrode (nickel electrode), where it is absorbed. This bond releases energy. During charging, the hydrogen movement is reversed.

[0003] Nickel-metal hydride batteries, in particular, are designed to limit the nickel electrodes to a starved electrolyte state, which is done to prevent overcharge and overdischarge of the battery cell, and controls the battery cell's chemical reaction and state of charge via the gas phase.

[0004] When the battery cell is charged, hydrogen is transported from the nickel hydroxide to the metal hydride by water molecules in the alkaline electrolyte. When the battery cell is discharged, hydrogen is transported back to the nickel hydroxide electrode in the form of water molecules.

[0005] PCT Publication WO2017 / 069691 states that properly balancing the nickel electrode capacity with the metal hydride electrode capacity, with both the appropriate amount of overcharge reserve and overdischarge reserve, is essential for the battery module to function well and achieve stable, long-term charge and discharge performance. The addition of oxygen gas, hydrogen gas, or hydrogen peroxide can provide adequate overcharge and discharge reserve and replenish the electrolyte, extending the life of the battery module and increasing the number of cycles possible.

[0006] The addition of oxygen is preferably carried out when the battery module is not in operation, and therefore, in order to optimize the operation of the battery module, the oxygen filling is preferably carried out in a manner that optimizes not only the capacity of the battery module but also the operating time.

[0007] In a paper titled "Increasing NiMH Battery Cycle Life with Oxygen" by Shen Yang et al., published in International Journal of Hydrogen Energy, 2018-03-29, ISSN 0360-3199, Vol 43, No 40, pp 18626-18631, they describe a study on the controlled addition of oxygen to restore balance between the electrodes of a nickel-metal hydride battery and replenish the electrolyte. Summary of the Invention

[0008] It is an object of the present invention to provide a method for adding oxygen to and reconditioning a battery module containing two or more battery cells, preferably nickel-metal hydride battery cells, which at least mitigates the drawbacks of the prior art.

[0009] At least one of these objects is achieved by the method according to claim 1.

[0010] Further advantages of the invention are provided by the features of the respective dependent claims.

[0011] According to a first aspect of the present invention, there is provided a method for reconditioning a battery module including two or more battery cells. The battery module has a casing that contains the battery cells and encloses a common gas space. Each battery cell of the battery module includes a first electrode, a second electrode, a porous separator, and an aqueous alkaline electrolyte disposed between the first electrode and the second electrode. The porous separator, the first electrode, and the second electrode are configured to allow gas transfer between the electrodes, thereby enabling hydrogen and oxygen exchange. The casing further includes an inlet for adding a gas or liquid to the common gas space of the casing, the inlet for adding a gas or liquid to the common gas space of the casing being disposed within the common gas space of the casing. The method includes acquiring data related to the battery module, the data relating to at least the number of battery cells in the battery module and the energy capacity of the battery module. The method also includes acquiring data on an indicator parameter related to the internal resistance of at least one of the battery cells, and, if the indicator parameter exceeds a predetermined first threshold, determining, based on the indicator parameter and data on the battery module, an amount of oxygen to be charged into the battery module to reduce the indicator parameter to a level below the first threshold. The method also includes, if it is determined to be safe, initiating charging of the battery module with the determined amount of oxygen. This initiation may include instructing the battery module to send a gas container containing the correct amount of oxygen at the correct pressure. Alternatively, if the battery module is connected to an oxygen pipe, this initiation may include initiating charging of oxygen from the oxygen pipe.

[0012] The method according to the first aspect of the present invention can optimize the operation of the battery. This method can optimize not only the capacity of the battery module but also the operating time of the battery module. The first threshold value at an appropriate level can fill the battery with oxygen at an optimal level to avoid operating the battery with high internal resistance, while also preventing the time between fillings from being too short.

[0013] The method is implemented in a control circuit that includes a computer.

[0014] The step of acquiring data on the indicator parameters of at least two of the battery cells is preferably performed by receiving data from a measurement unit configured to obtain values ​​necessary for determining the indicator parameters of the battery module. The number of cells involved in this determination is subject to practical limitations. Typically, only the electrode contacts of the battery module are accessible. Therefore, indicator parameters such as SOH and internal resistance are determined for all battery cells in the battery module.

[0015] The step of obtaining data about the battery modules (this data relates to at least the number of battery cells in the battery modules, the energy capacity of the battery modules, and, if necessary, the volume of the common gas space) can be performed in many different ways. One alternative is for the measurement unit to be configured to transmit data about the battery modules to a control unit that executes the method. While the data may be transmitted from the measurement unit, it is preferable for the measurement unit to transmit only the identification number to minimize the complexity of the measurement unit. Upon receiving the identification number from the measurement unit, the computer can retrieve the data from memory. As described above, this data relates to at least the number of battery cells in the battery modules, the energy capacity of the battery modules, and, if necessary, the volume of the common gas space. This data is necessary for determining the amount of oxygen to be charged into the battery modules. However, the actual number of battery cells in the battery modules, the energy capacity of the battery modules, and the volume of the common gas space need not be used for the determination. According to one alternative, the control unit may refer to a lookup table in memory to obtain battery data corresponding to the identification number of the battery modules. The battery data may, for example, be a model number that identifies the type of battery. The control unit may then retrieve the required oxygen charge from another lookup table based on the obtained indication parameters and the model number. The required oxygen charge in the lookup table may be based on previous experiments using similar battery types. The model number defines a battery module having a predetermined number of battery cells, a predetermined energy capacity, and, if necessary, a predetermined common gas space volume.

[0016] Preferably, when the obtained indication parameter is an internal resistance, which means the internal resistance across multiple battery cells, an average internal resistance per cell is calculated, so that the same first threshold value can be used for all types of batteries that may have different numbers of battery cells.

[0017] The method may include obtaining voltage indications of the at least two of the battery cells, determining whether the voltage indications of the at least two of the battery cells are within a predetermined voltage range, and determining that it is safe to fill the battery module with oxygen only if the obtained voltage indications of the at least two battery cells do not have values ​​outside the predetermined voltage range.

[0018] The predetermined voltage range is defined by a lower voltage indication threshold and an upper voltage indication threshold, and the voltage indication may be an open circuit voltage (OCV) on the battery module or a state of charge (SOC) of the battery module.

[0019] If the voltage indication of the battery module is within a predetermined voltage range and the battery module is filled with oxygen, it is advantageous to prevent the filling of oxygen to reduce the risk of fire. When the open circuit voltage is used as the voltage indication, it is preferable to calculate an average voltage per cell from the open circuit voltages across the at least two battery cells. In this case, only one voltage indication threshold needs to be used.

[0020] The method may also include initiating discharge or charging of the battery module to a voltage of each battery cell within a voltage range before initiating charging of the battery module with the determined amount of oxygen if it is determined that charging the battery module with oxygen is unsafe. According to one alternative, initiating discharge or charging may be sending a message to a battery operator to discharge or charge the battery. Alternatively, if the battery module is connected to an automatic discharge or charge device, initiating may include initiating automatic discharge or charge.

[0021] The charging of the battery module with inert gas can be synchronized with, or started simultaneously with, the charging of the battery module with oxygen. The combined charging of oxygen and inert gas can further reduce the risk of fire. If the battery module is connected to a gas pipe, it is preferred that the gas pipe contain the correct mixture of oxygen and inert gas.

[0022] The method may also include, after starting to fill the battery module with oxygen, acquiring a post-fill parameter related to the internal resistance of one of the at least two battery cells after filling; determining whether the post-fill parameter exceeds a predetermined second threshold; and, if the post-fill parameter exceeds the predetermined second threshold, determining an additional amount of oxygen to be filled into the battery module based on the post-fill parameter and data on the battery module to make the post-fill parameter less than the second threshold, and starting to fill the battery module with the determined additional amount of oxygen.

[0023] These steps ensure that sufficient oxygen has been added to the battery module to ensure optimal function and operation in the future. The second threshold is a value lower than the first threshold. Aiming for this second threshold increases the number of cycles before internal resistance increases and affects the performance of the battery module.

[0024] The method may further include a step of preparing a container for filling the battery module with the determined amount of oxygen to reduce the indicator parameter of the battery module. The pressure of the gas in the container depends on the volume of the container and the amount of gas in the container. For small containers, the container volume will be approximately the same as the oxygen filling amount. However, after filling the oxygen from the container, there will always be residual oxygen in the container. The flow of gas from the container to the battery module continues until the pressure in the container is the same as the pressure in the common gas space of the battery module.

[0025] According to a second aspect of the present invention, there is provided a computer program for reconditioning a battery module, the program comprising instructions which, when executed on at least one processor, cause the at least one processor to perform a method according to the first aspect of the present invention.

[0026] According to a third aspect of the present invention, there is provided a computer readable storage medium carrying a computer program for reconditioning a battery module according to the second aspect of the present invention.

[0027] According to a fourth aspect, there is provided a system for reconditioning a battery module, the system including a control circuit configured to perform the method according to the first aspect. The system may include a measurement unit configured to measure the voltage and applied or drawn current of the battery module to obtain the resistance, and configured to communicate with the control circuit. The control circuit may include a local control unit configured to determine at least the internal resistance from at least one measurement value of the battery cells and to control the charging of oxygen to the battery module, and a control unit communicating with the local control unit. The control unit is configured to retrieve data related to the battery module from a memory and determine the amount of oxygen to be charged based on the measurement value used to calculate the internal resistance retrieved from the local control unit and the data related to the battery module.

[0028] Preferred embodiments of the present invention will now be described with reference to the drawings. [Brief explanation of the drawings]

[0029] [Figure 1] 1 illustrates a battery system for reconditioning battery cells in a battery module. [Figure 2] 1 illustrates a flow diagram for a method for reconditioning battery cells in a battery module, according to one embodiment. [Figure 3a] 1 shows plots of different measurements of battery cell resistance and module voltage for both the battery module during cycling and for different battery modules. [Figure 3b] The normalized measurements (resistance ratio) of Figure 3a are shown as a function of the battery module voltage. [Figure 4]1 illustrates how several battery modules can be configured for monitoring and reconditioning according to a first alternative embodiment of the method. [Figure 5] 10 illustrates a method configured to monitor and recondition a battery pack including three battery modules according to a second alternative embodiment of the method. [Figure 6] This shows an example of battery module readjustment, showing how the internal resistance of each battery cell changes depending on the number of discharge / charge cycles. DETAILED DESCRIPTION OF THE INVENTION

[0030] In the following description of the preferred embodiments, reference is made to the drawings. The drawings are not drawn to scale and some dimensions may be exaggerated to clearly show all features. The same reference numerals are used for similar features in different drawings.

[0031] The terminology used herein is for the purpose of describing particular embodiments of the disclosure only and is not intended to be limiting of the invention. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise.

[0032] In this application, the term "indicative parameter" related to the internal resistance of a battery module includes not only the internal resistance but also a measure of the state of health (SOH) of the battery module, which may include the internal resistance and other parameters important in determining the state of the battery module, such as internal gas pressure.

[0033] In this specification, the term "internal resistance" is generally used to mean the internal DC resistance of each battery module, and therefore of each battery cell. The internal resistance is obtained by measuring the voltage drop during controlled discharge using a predetermined discharge current. The internal resistance is then calculated based on the measured voltage drop and the discharge current. An example is given in the following standard, IEC 63115-1, Ed. 1.0 (2020-01), Chapter 7.6.3, "Measurement of Internal DC Resistance."

[0034] Some of the exemplary embodiments presented herein are directed to methods for reconditioning battery cells, particularly battery cells having metal hydride (MH) electrodes. One example of such a battery cell is a nickel-metal hydride battery cell. As part of the development of the exemplary embodiments presented herein, a problem is first identified and discussed.

[0035] In nickel-metal hydride battery modules containing multiple battery cells, the performance of each battery cell decreases due to the drying of the electrolyte during charging and discharging. It has been found that adding gas restores electrode balance, promotes gas recombination, and consequently reduces internal pressure. This makes the battery less susceptible to unintentional overcharging and over-discharging. A depleted electrolyte design means that only minimal electrolyte is available within the battery module. Loss of electrolyte leads to performance degradation, primarily due to increased internal resistance. Electrolyte drying is the primary cause of limited cycle life. Electrolyte drying is primarily caused by excessive internal pressure within the battery cell, which can open a safety valve during overcharging or over-discharging, releasing oxygen and hydrogen gas. When two or more battery cells are connected by a gas barrier, electrolyte is lost unevenly from the battery cells. This also applies to battery modules that share a common gas space.

[0036] The main reason for this is that battery cells are not 100% identical, resulting in uneven charging. Due to uneven charging, some cells generate heat before others, causing water (in gaseous form) to move between the battery cells connected by gas and condense in the lower temperature areas. This causes water to move within the battery module. As a result, the internal resistance of some battery cells increases more quickly than other battery cells. This increase in internal resistance can lead to a shortened lifespan of the battery module.

[0037] FIG. 1 shows a battery system 50 for preparing a battery module 1, which includes several battery cells 2 connected in series with bipolar plates 3 to form a stack. The battery module 1 has a casing 4 that houses the battery cells and encloses a common gas space 5. Each battery cell 2 of the battery module 1 includes a first positive electrode, a second negative electrode, a porous separator, and an aqueous alkaline electrolyte disposed between the first and second electrodes. The separator, first electrode, and second electrode are configured to allow gas transfer between the two electrodes, thereby enabling hydrogen and oxygen exchange. The battery module 1 includes a positive end plate 18 and a negative end plate 19 that contact each end of the stack of multiple battery cells 2. The battery module 1 further includes a positive connector 11 connected to the positive end plate 18 and a negative connector 12 connected to the negative end plate 19. The battery casing further includes a gas inlet 25 for adding gas or liquid to the common gas space 5 of the casing 4. The positive connector 11 and the negative connector 12 constitute electrodes through which power can be extracted from the battery module 1. Also shown in FIG. 1 is a measurement unit 13 connected to the positive connector 11 and the negative connector 12 and configured to acquire data necessary to calculate indicative parameters related to the internal resistance of the battery module 1 between the positive connector 11 and the negative connector 12. The data acquired by the measurement unit 13 may include a voltage drop during discharge to determine the internal resistance, temperature, internal pressure, and current if a current detector is included in the measurement unit 13. The measurement unit 13 may also be configured to measure the open circuit voltage (OCV) between the positive connector 11 and the negative connector 12. Alternatively, the measurement unit 13 may be connected to acquire data for only one battery cell 2, as indicated by dashed line 15. However, manufacturing a battery module with this functionality would be very costly. An inlet valve 16 is connected to a gas inlet 25. In FIG. 1, a gas bottle 17 is connected to the inlet valve 16, if necessary. A local control unit 20 is connected to the measurement unit 13 and the inlet valve 16 and may be configured to calculate an indication parameter based on data provided by the measurement unit 13 .A safety valve 24, such as a burstable disc, is connected to the common space 5. The safety valve 24 prevents dangerous gas pressure from building up in the common gas space 5. A pressure sensor 23 may be connected to the common gas space 5 and configured to measure the internal pressure within the common gas space 5. Incidentally, WO2007 / 093626, assigned to the present applicant, discloses an example of a single nickel-metal hydride battery module.

[0038] 1 also shows a local control unit 20 connected to the pressure sensor 23, the inlet valve 16, and the measurement unit 13. The local control unit 20 communicates with the control unit 14, preferably wirelessly. Of course, the local control unit 20 could also be connected to the control unit 14 by wire. One or more intermediate sections could also be provided between the local control unit 20 and the control unit 14. Alternatively, the local control unit could be omitted, with the control unit 14 connected to the inlet valve 16 and the measurement unit 13. The control unit 14 could also be located at a remote location, for example, at a battery module manufacturer. The central control unit 14 is connected to or includes a memory 26.

[0039] The control unit 14 is configured to initiate measurements of indicator parameters, such as temperature, pressure, voltage and current required for calculating the internal resistance between the positive connector 11 and the negative connector 12 of the battery module, at predetermined intervals in the measurement unit 13 and to transmit this information together with the identification information of the battery module 1 to the control unit 14. For this purpose, the control unit 14 sends a request to the local control unit 20, which returns the current indicator parameters and the open circuit voltage of the battery module as an answer. The internal resistance is not measured directly by the measurement unit 13. The measurement unit 13 measures the voltage drop in the battery module 1 during discharge with a predetermined discharge current and then calculates the internal resistance.

[0040] The battery module 1 is discharged and charged during use, and the internal resistance of the battery module increases as the number of charge / discharge cycles increases.

[0041] 1 shows a battery module 1 having battery cells in a bipolar configuration, the present invention should not be limited to a bipolar configuration. Battery cells arranged in other types of configurations, such as cylindrical or prismatic configurations, can benefit from the present invention, provided that a common gas space is provided for multiple battery cells in the battery module.

[0042] FIG. 2 is a flow diagram of a method for reconditioning a battery module 1. The method includes a first step 101 of acquiring data related to the battery module 1. This may be done in one of many different ways. One example of how to acquire data is for the local control unit 20 to send a unique identification number to the control unit 14. The control unit 14 may then retrieve the data related to the battery module from the memory 26. In a second step 102, an indicator parameter, exemplified as the internal resistance of at least one of the battery cells 2, is acquired. According to one embodiment, data for calculating the internal resistance is obtained from the measurement unit 13, and the control circuit (e.g., the local control unit 20) determines the internal resistance between the positive connector 11 and the negative connector 12. In this case, the internal resistance may be determined as an average internal resistance per battery cell or as a total internal resistance across all battery cells of the battery module. According to another embodiment, the measurement unit 13 acquires data for calculating the internal resistance across each battery cell (as indicated by the dashed line 15 in FIG. 1). In this case, the internal resistance is determined as the actual internal resistance per battery cell. In this example, the local control unit 20 then transmits the resistance determination to the control unit 14 .

[0043] In a third step 103, the control unit 14 calculates the internal resistance R i is a predetermined first resistance threshold R t1It is determined whether the first resistance threshold R t1 may be stored in the memory 26 or may be implemented in the method, i.e., in a computer program controlling the execution of the method. t1 If R refers to a threshold for a single battery cell 2, the threshold may be included in the program. However, the first resistance threshold R t1 If R refers to a resistance threshold for multiple battery cells 2, the value is stored in memory 26 along with data regarding the battery module, which may include the number of battery cells in the battery module and the capacity of each battery cell. More specifically, the control unit 14 receives the identification number from the local control unit 20 and retrieves data regarding the battery module from memory 26. Optionally, this data includes the volume of the common gas space 5. The control unit then divides the resulting resistance value by the number of battery cells 2 to arrive at an average internal resistance per battery cell 2. The average internal resistance R per battery cell 2 ic is a predetermined first resistance threshold R t1 If it does not exceed the predetermined value, the control unit 14 waits for a waiting time T w Wait for a period of time.

[0044] Average internal resistance R per battery cell ic is a predetermined first resistance threshold R t1 If the resistance exceeds the first resistance threshold R, the control unit 14 sets the internal resistance of the battery module 1 to the first resistance threshold R in the fourth step 104, as shown in step 109. t1 to a level less than a second predetermined threshold R t2 To reduce the internal resistance to a level less than R i and determine the amount of oxygen to be filled into the battery module 1 based on data relating to the battery module 1. The data used to determine the required amount of oxygen preferably includes information relating to the capacity of each battery cell 2 and, if necessary, the volume of the common gas space 5. The required amount of oxygen can be determined in a number of different ways.

[0045] According to another embodiment, the control unit 14 relies on previous measurements to determine the required amount of oxygen to be charged into the common space 5 of the battery module 1. The control unit 14 may refer to a lookup table in the memory 26 to retrieve battery data corresponding to the identification number of the battery module. The battery data may, for example, be a model number identifying the type of battery. The control unit 14 may then retrieve the required amount of oxygen from another lookup table based on the determined internal resistance and model number. The required amount of oxygen in the lookup table may, in turn, be based on previous experiments with similar battery types. Note that data regarding the temperature of the battery module is important because the internal resistance changes as a function of temperature, and the measured voltage drop during discharge must be normalized based on the temperature to determine the correct amount of oxygen to be charged.

[0046] According to another alternative, the control unit 14 obtains the data required to calculate the amount of oxygen from a look-up table, which may include the number of battery cells 2 in the battery module 1, the temperature, and the volume of the common gas space 5 included in determining the number of battery cells 2 and, if necessary, the internal resistance.

[0047] This method also provides voltage indication U for each battery cell. c The voltage indication may be the open circuit voltage (OCV) of the battery module at the measured temperature or the state of charge (SOC) indicating that it is safe to add oxygen to the battery module. In this example, OCV is used and the determination in step 105 is made for a battery module U having a plurality of battery cells 2. m The open circuit voltage Uc is then measured and divided by the number of battery cells in the battery module obtained in step 101. t0 < U c < U t1It is then determined whether the battery cell voltage is within the predetermined voltage range. In this case, the control unit 14 must also have information on the number of battery cells 2 included in the voltage measurement. If it is determined in the sixth step 105a that the voltage is within the predetermined voltage range, it is determined that it is safe to charge the battery module 1 with oxygen, as shown in the seventh step 107, which includes charging the battery module 1 with a predetermined amount of oxygen. On the other hand, if the battery cell voltage is not within the voltage range, an optional step 106 is executed to adjust the battery cell voltage of the battery module before repeating step 105. This is because the battery cell voltage is equal to or greater than the upper voltage indication threshold U. c ≧ U t1 This means that the battery module is discharged when the battery cell voltage is equal to or lower than the lower limit voltage instruction threshold U. In the discharge step, the battery module may be actively discharged, or the battery module may be allowed to self-discharge by waiting for a certain period of time. c ≦ U t0 If so, the battery module is charged (step 106b). Performing these optional steps 105, 105a, and 106 is advantageous in reducing the risk of fire if oxygen fills the battery module when the voltage is too high or too low (which can be caused by the fact that the oxygen recombination rate is too high at high voltages across the battery cells). If the battery cell voltage is too low, oxygen will react directly with the negative electrode, which is not protected from occluded hydrogen.

[0048] Figure 3a is a plot of multiple measurements of the resistance of a battery module at room temperature, i.e., +20°C ± 2°C, versus the corresponding open circuit voltage (OCV) of the battery module. The data in Figure 3 is for a battery module having 10 battery cells 2, with the y-axis being the combined voltage of all the battery cells, i.e., the 10 battery cells, and the x-axis being the average internal resistance for the battery cells. The battery cell voltage threshold U tis a function of the battery cell resistance, as shown in Figure 3a. The four circled dots 27 indicate measurements where the voltage was too high for oxygen charging. Note that some of the data points in the figure are from the same battery module that has been charged with oxygen multiple times, and some are from modules that have only been charged a few times.

[0049] As mentioned above, if it is determined that it is unsafe to charge the battery module with oxygen, the method may include an optional intermediate step 106 of adjusting the battery cell voltages of the battery module to a battery cell voltage within an indicated voltage range before starting charging of the battery module in step 107. As an example, if the upper voltage indication threshold U t1 is 1.39 V / cell, and the lower voltage indication threshold Ut0 is 1.3 V / cell. Like the lower voltage indication threshold, the upper voltage indication threshold is temperature dependent and can be normalized to a given temperature range (e.g., room temperature) to ensure the OCV is within the voltage range of 1.3 to 1.39 V / cell. Otherwise, thresholds for different temperatures would be required to determine when it is safe to charge the battery module with oxygen. Furthermore, as shown by line 28 in FIG. 3a, the upper voltage indication threshold can vary as a function of the measured internal resistance.

[0050] Figure 3b shows the resistance ratio (R ratio) of the measured resistance in Figure 3a, normalized by the initial resistance value, called the R ratio. It has been shown that when the R ratio is too high, e.g., >3.5 (as shown by line 29), corrosion of the negative electrode material in the battery cell is severe and cannot be restored by adding oxygen. Furthermore, it has been found that the optimal condition for battery cell reconditioning is when the R ratio is between 1.5 and 2.0. This is because an R ratio below 1.5 results in insufficient overcharge reserve capacity, leaving little hydrogen available for optimal electrolyte balance (consumed by hydrogen generated by corrosion). Oxygen reacts with the hydrogen in the overdischarge reserve capacity, disrupting the electrode balance and resulting in capacity loss.

[0051] Upper voltage indication threshold U t1may be set to a fixed value, for example 1.39 V / cell, or may be varied as a function of the R ratio, as shown by line 30 in FIG. 3b.

[0052] When determining whether it is safe to fill a battery module with oxygen based on the SOC, the upper threshold of the SOC is 95% and the lower threshold is 50%.

[0053] The battery module 1 may be filled with an inert gas, such as nitrogen, argon, helium, or air, in conjunction with the oxygen filling, thereby reducing the risk of fire during filling. The inert gas may be added sequentially with the oxygen filling (before, after, and / or alternately), or the inert gas may be introduced simultaneously as a mixture with the oxygen. FIG. 1 shows that a gas container 17 is connected to the gas inlet 25 via an inlet valve 16. The control unit 14 may be configured to initiate filling by initiating delivery of the gas container 17 to the battery module 1 site.

[0054] In some embodiments, initiating charging of the battery packs 107 can also include adding hydrogen gas to the common gas space before charging the battery packs with oxygen, which can further improve the operating efficiency of the battery modules, but this can only be performed if the voltage indication is within the voltage indication range and it is safe for the battery modules to be charged with oxygen.

[0055] As a precaution, after starting oxygen charging to the battery module in the seventh step 107, the method optionally includes an eighth step 108, in which the control unit 14 obtains post-charging parameters related to the internal resistance of the at least one battery cell 2 after charging, and in step 109, calculates the post-charging parameters, such as the internal resistance R of each battery cell 2. i is a predetermined second threshold value, for example, a second resistance value R t2 If so, the method returns to step 104 and determines whether the internal resistance exceeds the second resistance threshold R t2The amount of additional oxygen to be charged into the battery pack is determined to reduce the resistance to a level below the second resistance threshold R. This amount is the amount of oxygen charged into the battery pack in step 107. t2 is the first resistance threshold R t1 This makes it possible to reduce the internal resistance R i is again the first resistance threshold R t1 This provides a more robust method since the battery can be cycled more times before exceeding the oxygen limit. An optional feedback loop from step 109 to step 104 is not required in principle, but if the battery module needs to be filled with additional oxygen, the battery module is filled with a determined amount of oxygen. For this step to be useful, the oxygen filling must occur more or less instantaneously. If the container 17 must be sent for oxygen filling, there may be a delay of several hours or even days before the battery module is filled with oxygen.

[0056] Average internal resistance R i The level is the second resistance threshold R t2 If it is lower, the method may proceed to optional step 110, where it is determined that additional QA steps are required to increase the energy capacity of the battery module. The low energy capacity of the battery module is a side effect of overfilling the battery module with oxygen, and the QA steps (including charging and discharging the battery module) increase the energy capacity with only a small effect on the internal resistance of the cells in the battery module. If QA is required, step 111 is performed until the energy capacity of the battery module is OK.

[0057] The determination step 109 may be replaced by a QA step, since the internal resistance is determined as part of the QA step.

[0058] It is contemplated that the control unit may perform step 101 of acquiring battery pack data differently depending on the length of time that has elapsed since the last time the data was acquired. The data may also be stored in the working memory of the control unit 14 for a short period of time.

[0059] 4 illustrates how multiple battery modules 1 can be configured for monitoring and readjusting according to a first alternative embodiment of the method. Multiple battery modules 1 are connected to a common gas line 19 via respective measurement units 13 and respective inlet valves 16. All measurement units 13 and all inlet valves 16 communicate with a local control unit 20, which controls all inlet valves 16, via a bus 21. The local control unit 20 may communicate with a remote control unit 14. If any battery module 1 is determined to be filled with gas, the control unit 14 sends a control signal to the local control unit 20, which controls the associated inlet valve 16 to open.

[0060] FIG. 5 illustrates how a battery pack consisting of multiple modules 1 can be configured to be monitored and reconditioned according to a second alternative embodiment of the present method. In FIG. 5, multiple battery modules, such as those disclosed in commonly assigned WO 2018 / 111182, are stacked together to form a battery pack 10. The battery modules 1, 1′, and 1″ included in the battery pack 10 share a common gas space 5. The internal resistance may be measured individually for each battery module. If the average internal resistance per battery cell 2 in any battery module exceeds a first resistance threshold Rt1, the common gas space 5 may be filled with gas according to the method described in connection with FIG. 2.

[0061] The battery modules are connected to a gas bottle 17 via a common measuring unit 13 and inlet valve 16. The measuring unit 13 and inlet valve 16 are in communication with a local control unit 20 which controls the inlet valve 16. The local control unit 20 may be in communication with a remote control unit 14. When it is determined that any battery module needs to be filled with gas, the control unit 14 sends a control signal to the local control unit 20 which in turn controls the inlet valve 16 to be opened.

[0062] The above description illustrates how the control unit 14 may perform this method. The control unit may include at least one processor 14' (FIG. 1). The processor may be programmed with a computer program including a plurality of instructions that, when executed by the at least one processor, cause the processor to perform the method described above in relation to FIG. 2. This method in the control unit may be computer-implemented. Example

[0063] Figure 6 illustrates the reconditioning of the battery module 1 and shows how the internal resistance per battery cell 2 varies with the number of discharge / charge cycles. The table below contains the reconditioning details. [Table 1]

[0064] The term "R ratio" is an index reflecting the increase in internal resistance from the initial value before the start of charge-discharge cycles to the point when the internal resistance increases to a first predetermined resistance threshold, e.g., 15 mΩ. In Table 1, the first R ratio is calculated as 3.06, which means that the initial average internal resistance of the battery module is equal to 17.417 mΩ / 3.06=5.69 mΩ.

[0065] The first portion 31 of the curve in Figure 6 shows how the internal resistance per battery cell 2 changes with the number of charge-discharge cycles of the battery module 1. The internal resistance per battery cell 2 was 5.69 mΩ before the first charge-discharge cycle. After 641 cycles, the internal resistance per battery cell 2 was 17.417 mΩ, resulting in an R ratio of 3.06. Next, oxygen was added incrementally during the first charge, and the internal resistance per battery cell 2 was measured after each charge. After the first charge of 3 liters of oxygen, the internal resistance per battery cell 2 was 11.11 mΩ. After the second charge of 3 liters of oxygen, the internal resistance per battery cell 2 was 8.333 mΩ. After the third charge of 3 liters of oxygen, the internal resistance per battery cell 2 was 6.566 mΩ. Finally, after the fourth charge of 1.5 liters of oxygen, the internal resistance per battery cell 2 was 6.06 mΩ.

[0066] The second portion 32 of the curve in Figure 6 shows how the internal resistance per battery cell 2 changed with the number of charge-discharge cycles of the battery module 1 after the first charge. The internal resistance per battery cell 2 after 475 cycles was 16.636 mΩ, and therefore the R ratio was 2.75. Next, oxygen was added incrementally during the second charge, and the internal resistance per battery cell 2 was measured after each charge. After the first charge of 3 liters of oxygen, the internal resistance per battery cell 2 was 11.005 mΩ. After the second charge of 3 liters of oxygen, the internal resistance per battery cell 2 was 8.006 mΩ. The process indicated by repeated QA is a process for adjusting the discharge reserve to further increase the capacity of the battery module, and this process involves charging and discharging the battery module 1.

[0067] After the third oxygen charge of 3 liters, the internal resistance per battery cell 2 was 6.333 mΩ.

[0068] The third portion 33 of the curve in Figure 6 shows how the internal resistance per battery cell 2 changed with the number of charge / discharge cycles of the battery module 1 after the second charge. After approximately 601 cycles, the resistance per battery cell 2 was 15.636 mΩ, thus giving an R ratio of 2.47. Next, oxygen was added in two stages during the third charge, and the internal resistance was measured after each charge. After the first charge of 3.29 liters of oxygen, the internal resistance per battery cell 2 was 10.539 mΩ. After the second charge of 2.33 liters of oxygen, the internal resistance per battery cell 2 was 7.397 mΩ.

[0069] After the third charging, the battery module was subjected to a charge-discharge cycle. The fourth portion 34 of the curve in Figure 6 shows the state of internal resistance per battery cell at 263 cycles, indicating that the battery module is still being cycled.

[0070] The present disclosure relates to a method for reconditioning a battery module 1 including two or more battery cells 2. The battery module has a casing 4 containing the plurality of battery cells and enclosing a common gas space 5. Each battery cell 2 of the battery module 1 includes a first electrode, a second electrode, a porous separator, and an aqueous alkaline electrolyte disposed between the first and second electrodes. The porous separator, the first electrode, and the second electrode are configured to allow gas transfer between the electrodes to allow exchange of hydrogen and oxygen, and the casing 4 further includes an inlet 25 for adding gas or liquid to the common gas space 5 of the casing 4. The method includes steps 101 to 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 17 i102, obtaining an indication parameter related to the battery module 1; if the indication parameter exceeds a predetermined first threshold, determining 104 an amount of oxygen to be charged into each battery cell of the battery module 1 based on the indication parameter and the obtained data about the battery module; obtaining 105 a voltage indication Uc, e.g., OCV or SOC, at a measured temperature for at least one of the battery cells; determining 105 a whether the voltage indication for at least one of the battery cells exceeds a predetermined upper voltage indication threshold Ut1 (e.g., OCV at 1.39 V / cell measured at a temperature of +20°C ± 2°C or 95% SOC); and determining 105 b whether the obtained voltage indication Uc for at least one of the battery cells exceeds the predetermined upper voltage indication threshold Ut1 (e.g., OCV at 1.39 V / cell measured at a temperature of +20°C ± 2°C or 95% SOC). t1 If it is lower, step 107 starts charging the battery module 1 with the amount of oxygen to reduce the indicator parameter to a level below the first threshold value; c , for example, OCV or SOC, step 105a, determining whether a voltage indication for at least one of the battery cells is below a predetermined lower voltage indication threshold Ut0 (e.g., OCV at 1.3 V / cell measured at a temperature of +20°C ± 2°C or 50% SOC), and step 107, if the obtained voltage indication Uc for at least one of the battery cells is higher than the predetermined lower voltage indication threshold Ut0, starting to charge an amount of oxygen into the battery module 1 to reduce the indication parameter to a level below the first threshold.

[0071] In some embodiments, the indicator parameter is an internal resistance R of at least one of the battery cells 2. i The first threshold is selected to be a first resistance threshold R t1 and the charging of oxygen into the battery module 1 is performed by increasing the internal resistance of at least one of the battery cells to a first resistance threshold R t1 Reduce to a level below.

[0072] In some embodiments, the indication parameter relates to the state of health (SOH) of the battery module.

[0073] In some embodiments, the upper voltage indication threshold U t1 is the internal resistance R of the at least one battery cell i is a function of an instruction parameter related to

[0074] In some embodiments, the method further comprises: determining a voltage indication U obtained for at least one of the battery cells; c is the predetermined upper limit voltage indication threshold U t1 If so, before starting step 107 of filling the battery module with the determined amount of oxygen, the voltage of the at least one battery cell is increased to an upper voltage indication threshold U t1 The method further includes step 106a of discharging the battery module to a voltage indication below 106A.

[0075] In some embodiments, the method further comprises determining whether a voltage indication at the measured temperature for at least one of the battery cells is below a predetermined lower voltage indication threshold U t0 (e.g., an OCV of 1.3 V / cell measured at a temperature of +20° C.±2° C. or 50% SOC) and a step 105 a determining whether the obtained voltage indication U for at least one of the battery cells is less than or equal to the OCV of the battery cell. c The method further includes step 107 of initiating filling when Vt exceeds a predetermined lower voltage indication threshold Ut0.

[0076] In some embodiments, the method further comprises: determining a voltage indication U obtained at a measured temperature for at least one of the battery cells; c is the predetermined lower limit voltage indication threshold U t0 If the voltage of at least one of the battery cells is less than or equal to the lower voltage indication threshold U before starting to fill the battery module with the determined amount of oxygen in step 107, t0 The method further includes step 106b of charging the battery module to a voltage indication above 106b.

[0077] In some embodiments, the initiating charging step 107 further includes charging the battery modules with hydrogen before charging the battery modules with oxygen, and this step is performed only if it is safe to charge the batteries with oxygen.

[0078] According to some implementations, the voltage indication is selected to be an open circuit voltage for at least one of the battery cells, and the upper and lower voltage indication thresholds are temperature dependent.

[0079] In some embodiments, the voltage indication is related to the State of Charge (SOC) of the battery module.

[0080] In some embodiments, the step 107 of initiating charging of the battery module 1 further includes charging the battery module with an inert gas in conjunction with charging the battery module with oxygen.

[0081] In some embodiments, the inert gas is selected to be any combination of argon, nitrogen, helium, and / or air.

[0082] In some embodiments, initiating filling step 107 further includes initiating preparation of container 17 with the determined filling amount of oxygen to reduce an indicator parameter of at least one of the battery cells of the battery module.

[0083] In some embodiments, the method further comprises measuring the internal resistance R of the battery module after charging the battery module with oxygen. i The method further includes a step 108 of acquiring a post-filling parameter related to the battery module 1, a step 109 of determining whether the post-filling parameter exceeds a predetermined second threshold (the second threshold being smaller than the first threshold), and if the post-filling parameter exceeds the predetermined second threshold, a step of determining an additional amount of oxygen to be filled into the battery module 1 based on the post-filling parameter and the data of the battery module 1 so as to make the post-filling parameter less than the second threshold, and filling the battery module 1 with the determined additional amount of oxygen.

[0084] In some embodiments, the battery modules are selected to be nickel metal hydride (NiMH) battery modules.

[0085] The present disclosure also relates to a computer program for reconditioning a battery module, the program including instructions that, when executed by at least one processor 14', cause the at least one processor 14' to perform the above-described method. The present disclosure also relates to a computer-readable storage medium having stored thereon a computer program for reconditioning a battery module.

[0086] The present disclosure also relates to a container 17 for reconditioning a battery module 1. The container is filled with at least a fill amount of oxygen to reduce an indicator parameter related to the internal resistance of at least one of the battery cells in the battery module 1, and the oxygen fill amount is determined according to the above method. As described above, the gas pressure in the container depends on the volume of the container and the amount of gas in the container. For a small container, the container volume is approximately equal to the oxygen fill amount. However, after filling the container with oxygen, a residual amount of oxygen always remains in the container. The gas flow from the container to the battery module continues until the pressure in the container becomes equal to the pressure in the common gas space of the battery module. Therefore, the gas volume in the container needs to be slightly larger than the fill amount.

[0087] The present disclosure also relates to a system 50 for reconditioning a battery module 1 including two or more battery cells 2. The battery module has a casing 4 that contains the battery cells and encloses a common gas space 5. Each battery cell 2 of the battery module 1 includes a first electrode, a second electrode, a porous separator, and an alkaline aqueous solution disposed between the first electrode and the second electrode, where the porous separator, the first electrode, and the second electrode are configured to allow gas transfer between the electrodes to exchange hydrogen and oxygen. The casing 4 further includes an inlet 25 for adding a gas or liquid to the common gas space 5 of the casing 4. The system includes control circuits 14, 20 configured to execute the above-described method.

[0088] In some embodiments, the system further includes a measurement unit 13 configured to obtain parameters (such as voltage, internal pressure, temperature, etc.) used to determine an indicative parameter related to the internal resistance of the battery module 1. The measurement unit 13 is configured to communicate with the control circuits 14, 20.

[0089] In some embodiments, the control circuit includes a local control unit 20 configured to obtain an indication parameter related to the internal resistance of at least one of the battery cells 2 and to control the charging of oxygen to the battery module 1, and a control unit 14 in communication with the local control unit 20. The control unit is configured to obtain data related to the battery module from the memory 26 and determine the amount of oxygen to be charged based on the indication parameter obtained from the local control unit 20 and the data related to the battery module 1.

[0090] Aspects of the present disclosure are described with reference to drawings, e.g., block diagrams and / or flow diagrams. It will be understood that some entities in the drawings, e.g., blocks of the block diagrams, and combinations of entities in the drawings, can be implemented by computer program instructions, which can be stored in a computer-readable memory and loaded into a computer or other programmable data processing apparatus. Such computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, and / or other programmable data processing apparatus to produce a machine, such that the instructions, executed by the processor of the computer and / or other programmable data processing apparatus, create means for performing the function(s) / act(s) specified in the block diagram(s) and / or flow diagram(s) block(s).

[0091] Depending on the implementation and aspects of the present disclosure, the functions or steps noted in each block may occur out of the order noted in the operational illustrations. For example, two blocks shown in succession may in fact be executed substantially simultaneously, or the blocks may sometimes be executed in the reverse order, depending on the functions / acts involved. Also, the functions or steps noted in each block may be executed sequentially in a loop, according to some aspects of the present disclosure.

[0092] In the drawings and specification, illustrative embodiments of the present disclosure have been disclosed. However, many variations and modifications can be made to these embodiments without substantially departing from the principles of the present disclosure. Accordingly, the present disclosure is to be regarded as illustrative rather than restrictive, and is not limited to the particular embodiments described above. Accordingly, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

1. A method for reconditioning a battery module (1) including two or more battery cells (2), the battery module having a casing (4) containing the battery cells and enclosing a common gas space (5), each battery cell (2) of the battery module (1) including a first electrode, a second electrode, a porous separator, and an aqueous alkaline electrolyte disposed between the first electrode and the second electrode, the porous separator, the first electrode, and the second electrode configured to allow gas transfer between the electrodes to enable hydrogen and oxygen exchange, the casing (4) further including an inlet (25) for adding a gas or liquid to the common gas space (5) of the casing (4), the method comprising: acquiring (101) data relating to the number of battery cells in the battery module (1), the temperature of the battery module (1), and the energy capacity of the battery module (1); The internal resistance (R ｉ obtaining (102) instruction parameters related to the determining (104) a charge amount of oxygen to be charged into each battery cell of the battery module (1) based on the indication parameter and acquired data related to the battery module when the indication parameter exceeds a predetermined first threshold value; A voltage indication (U) for at least one of the battery cells ｃ ) (105) The voltage indication for at least one of the battery cells is a predetermined upper voltage indication threshold (U ｔ１ ) or not (105a); The obtained voltage indication (U) for at least one of the battery cells ｃ ) is a predetermined upper limit voltage indication threshold (U ｔ１ ), starting (107) the charging of the battery module (1) with oxygen to reduce the indicator parameter to a level below the first threshold; and measuring the voltage indicator (U) of at least one of the battery cells. ｃ ) and determining whether the voltage indication for at least one of the battery cells is below a predetermined lower voltage indication threshold (U ｔ０ ) for at least one of the battery cells; and determining (105a) whether the obtained voltage indication (U ｃ ) is a predetermined lower limit voltage indication threshold (U ｔ０ ), starting (107) oxygen charging of the battery module (1) with the charge amount to reduce the indicator parameter to a level below the first threshold.

2. The indication parameter is the internal resistance (R ｉ ), and the first threshold is selected to be a first resistance threshold (R ｔ１ ), and charging the battery module (1) with oxygen reduces the internal resistance of at least one of the battery cells to a first resistance threshold (R ｔ１ 2. The method of claim 1, wherein the concentration of hydroxybenzoates is reduced to a level below 100 ppm.

3. 2. The method of claim 1, wherein the indicative parameter relates to a state of health of the battery module.

4. The upper limit voltage instruction threshold (U ｔ１ ) is the internal resistance (R ｉ 4. The method according to claim 1, wherein the difference is a function of an indicator parameter related to the difference.

5. an obtained voltage indication (U) for at least one of the battery cells; ｃ ) is the predetermined upper limit voltage indication threshold (U ｔ１ ) or more, Before starting the filling of the battery module with the determined amount of oxygen (step 107), the voltage of the at least one cell among the battery cells is set to the upper voltage indication threshold (U ｔ１ 5. The method of claim 1, further comprising the step of discharging the battery module to a level below 106a.

6. A voltage indication for at least one of the battery cells is below a predetermined lower voltage indication threshold (U ｔ０ ) or less (105a); The obtained voltage indication (U) for at least one of the battery cells ｃ ) is the predetermined lower limit voltage indication threshold (U ｔ０ 6. The method of claim 1, further comprising the step of: initiating filling (107) if the difference between the first and second pressures exceeds the first pressure.

7. The obtained voltage indication (U) for at least one of the battery cells ｃ ) is the predetermined lower limit voltage indication threshold (U ｔ０ ), before starting the step (107) of filling the battery module with the determined amount of oxygen, the voltage of the at least one cell of the battery cells is set to the lower voltage indication threshold (U ｔ０ 7. The method of claim 6, further comprising the step of charging the battery module to a level above 106b.

8. 8. The method of claim 6 or 7, wherein the step of initiating charging (107) further comprises charging the battery modules with hydrogen before charging the battery modules with oxygen.

9. 9. The method of claim 1, wherein the voltage indication is selected to be an open circuit voltage of at least one of the battery cells, and wherein upper and lower thresholds for the voltage indication are temperature dependent.

10. 9. The method of any one of claims 1 to 8, wherein the voltage indication is related to the state of charge of the battery module.

11. 10. The method according to any one of claims 1 to 9, wherein the step (107) of initiating the filling of the battery module (1) further comprises filling the battery module with an inert gas in conjunction with filling the battery module with oxygen.

12. 12. The method of claim 11, wherein the inert gas is selected to be any combination of argon, nitrogen, helium and / or air.

13. 13. The method according to any one of claims 1 to 12, wherein the step of initiating the filling (107) further comprises the step of initiating the preparation of a container (17) with the determined amount of oxygen to lower an indicator parameter of at least one of the battery cells of the battery module.

14. After filling the battery module (1) with the amount of oxygen, The internal resistance (R ｉ obtaining (108) post-fill parameters related to the determining (109) whether the post-fill parameter exceeds a second predetermined threshold value that is lower than the first threshold value; If the post-filling parameter exceeds the predetermined second threshold, determining, based on the post-filling parameter and data of the battery module (1), an additional charge amount of oxygen to be charged into the battery module (1) in order to reduce the post-filling parameter to a level below the second threshold; 14. The method according to any one of claims 1 to 13, further comprising the step of charging the battery module (1) with the determined additional charge of oxygen.

15. 15. The method of any one of claims 1 to 14, wherein the battery modules are selected to be nickel-metal hydride (NiMH) battery modules.

16. 16. A computer program for reconditioning a battery module, comprising instructions that, when executed on at least one processor (14'), cause the at least one processor (14') to perform the method of any one of claims 1 to 15.

17. A computer-readable storage medium having the computer program of claim 16 for reconditioning a battery module.

18. 16. A system (50) for reconditioning a battery module (1) including two or more battery cells (2), the battery module having a casing (4) containing the battery cells and enclosing a common gas space (5), each battery cell (2) of the battery module (1) including a first electrode, a second electrode, a porous separator, and an aqueous alkaline electrolyte disposed between the first electrode and the second electrode, the porous separator, the first electrode, and the second electrode configured to transfer gas between the electrodes to enable hydrogen and oxygen exchange, the casing (4) further including an inlet (25) for adding gas or liquid to the common gas space (5) of the casing (4), and the system including a control circuit (14, 20) configured to perform the method of any one of claims 1 to 15.

19. 19. The system of claim 18, further comprising a measurement unit (13) configured to acquire parameters used to determine an indicator parameter related to the internal resistance of the battery module (1), the measurement unit (13) being configured to communicate with the control circuit (14, 20).

20. The control circuit a local control unit (20) configured to obtain at least the indicator parameter related to the internal resistance of at least one of the battery cells (2) and to control the filling of oxygen into the battery module (1); 20. The system according to claim 18 or 19, further comprising a control unit (14) configured to communicate with the local control unit (20), to retrieve data relating to the battery module (1) from the memory (26), and to determine the oxygen filling amount based on the instruction parameters retrieved from the local control unit (20) and the data relating to the battery module (1).

Images