Method and apparatus for battery cell formation and / or aging during battery cell manufacturing

Abstract

The present disclosure provides methods and apparatus for battery cell formation and / or aging during battery cell manufacturing. The method (300) for formation / aging of at least one battery cell (B) provided in a battery cell chamber (210) includes charging and / or discharging (320) the at least one battery cell (B) according to a battery cell formation process and / or a battery cell aging process, acquiring a battery cell parameter (S) using at least one sensor provided in the battery cell chamber (210), and determining a level of quality (Q) based on the battery cell parameter (S), wherein the at least one sensor comprises an acoustic sensor (220) and / or a gas sensor (230). The method (300) may further include closed-loop control of the formation / aging process. Embodiments of the present disclosure particularly allow for improvements in the detection of SEI formation, allowing for formation / aging to be accelerated and / or optimised, and providing improvements in energy efficiency and processing time for battery cell formation / aging.

Description

[0001] METHOD AND APPARATUS FOR BATTERY CELL FORMATION AND / OR AGING DURING BATTERY CELL MANUFACTURING

[0002] TECHNICAL FIELD

[0003] Embodiments of the present disclosure relate to methods and apparatus for improved battery cell formation and / or aging during battery cell manufacturing. Particularly, embodiments of the present disclosure relate to methods and apparatus for quality control and monitoring of battery cell formation and aging by sensing gas generation during formation / aging, particularly using acoustic sensing and / or gas analysis to determine a level of SEI formation based on the gas generation.

[0004] BACKGROUND

[0005] The manufacturing of electrochemical energy storage devices, in particular lithium-ion battery cells, typically involves a number of key process steps. Important aspects in the manufacturing process are the formation and end-of-line (EOL) aging steps, which typically involve precisely charging and discharging the battery cell to condition the battery cell and ensure optimal performance and capacity.

[0006] Quality checks during the formation and aging during manufacturing are carried out to identify issues or defects in the formation process and / or the aging process which may affect the performance and lifespan of the battery cell. Due to the large amount of time and energy involved in formation and aging processes, many approaches in the current state of the art seek to accelerate formation and aging during the manufacturing process. However, the precise monitoring and quality control of the formation of the solid electrolyte interphase (SEI) layer in the battery cell has become a particular challenge in the optimisation of the formation and aging processes. The monitoring of voltage, current and temperature alone is insufficient for determining a level of SEI formation quality, and other methods of quality control and monitoring such as X-ray photoelectron spectroscopy (XPS) are typically only able to be performed offline and are typically cost-prohibitive.

[0007] One example of gas generation analysis which is used for offline SEI formation quality control is to provide the battery cell with an integrated gas collection bag, so that any gas generated in the battery cell during formation / aging is collected therein. After formation / aging is complete, the gas collection bag is separated from the rest of the battery cell pouch and the contents analysed in a lab environment, for example, by identifying types and concentrations of certain gas species generated. Although such a method allows accurate determination of the level and quality of SEI formation, the analysis may only be performed offline and the formation / aging process parameters cannot be adjusted in real-time.

[0008] In view of the deficiencies in the current state of the art, improved methods for quality control and monitoring of SEI formation during formation and end-of-line aging are sought.

[0009] SUMMARY

[0010] In view of the above challenges and problems arising in the state of the art, improved methods and apparatus for battery cell formation and aging during battery cell manufacturing are sought.

[0011] According to a first aspect of the present disclosure, a method for battery cell formation and / or aging during battery cell manufacturing is provided. The method includes providing at least one battery cell in a battery cell chamber, the battery cell chamber comprising at least one sensor configured for acquiring a battery cell parameter of the at least one battery cell, charging and / or discharging the at least one battery cell according to a battery cell formation process and / or a battery cell aging process, acquiring the battery cell parameter using the at least one sensor, and determining a level of formation quality and / or a level of aging quality based on the battery cell parameter, wherein the at least one sensor comprises an acoustic sensor and / or a gas sensor. According to a second aspect of the present disclosure, an apparatus for battery cell formation and / or aging is provided. The apparatus includes a battery cell chamber configured for accommodating at least one battery cell therein, at least one sensor configured for detecting a battery cell parameter of the at least one battery cell, a controllable charging unit configured for charging and / or discharging the at least one battery cell, and a controller configured for controlling a charging and / or discharging of the at least one battery cell according to a battery cell formation process and / or a battery cell aging process by controlling the controllable charging unit and by monitoring the battery cell parameter detected by the at least one sensor, wherein the at least one sensor comprises an acoustic sensor and / or a gas sensor.

[0012] Aspects of the present disclosure provide improved accuracy in determining a level of SEI formation quality in a battery cell undergoing formation / aging, allowing for the charging / discharging of the battery cell to be optimised without compromising the performance, capacity and lifespan of the resulting battery cell. Further, the methods of quality control and monitoring can be performed in-situ, allowing for improvements in manufacturing efficiency, shorter formation and / or aging times and a reduced rate of battery cells which are defective or of reduced quality.

[0013] Those skilled in the art will recognise additional features and advantages upon reading the following detailed description, and upon viewing the accompanying drawings.

[0014] BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The components in the figures are not necessarily to scale, instead emphasis is being placed upon illustrating the principles of the invention. Moreover, in the figures, like reference numerals designate corresponding parts. In the drawings:

[0016] Fig. 1 illustrates a flow chart of a battery manufacturing process; Fig. 2 illustrates a schematic view of a battery cell formation and / or aging apparatus according to embodiments of the present disclosure;

[0017] Fig. 3 illustrates a flow chart of a method of battery cell formation and / or aging during battery cell manufacturing according to embodiments of the present disclosure; and

[0018] Fig. 4 illustrates a schematic view of a battery cell formation and / or aging apparatus according to embodiments of the present disclosure.

[0019] DETAILED DESCRIPTION

[0020] Reference will now be made in detail to the various embodiments, one or more examples of which are illustrated in each figure. Each example is provided by way of explanation and is not meant as a limitation. For example, features illustrated or described as part of one embodiment can be used on or in conjunction with any other embodiment to yield yet a further embodiment. It is intended that the present disclosure includes such modifications and variations.

[0021] Within the following description of the drawings, the same reference numbers refer to the same or to similar components. Generally, only the differences with respect to the individual embodiments are described. Unless specified otherwise, the description of a part or aspect in one embodiment applies to a corresponding part or aspect in another embodiment as well.

[0022] After investigating the deficiencies in the current state of the art, the inventors identified several challenges in quality control and monitoring of SEI formation during the formation and aging processes during battery cell manufacturing. To overcome these challenges, methods and apparatus for in-situ sensing of the level and quality of SEI formation during the formation / aging process were investigated, and it was found that real-time analysis of acoustic signals generated by gas events occurring within the battery cell can be used as an indicator of SEI formation within. Further, in-line gas sensing of gases vented into the battery cell chamber may be used as an indicator of SEI formation and, optionally, the gas species and concentration of the vented gas may be analysed to indicate the level and quality of SEI formation. As the methods and apparatus according to the present disclosure allow for in-situ sensing, the charging / discharging parameters of the formation process and / or the aging process may be adjusted in real time to optimise the formation / aging process, allowing for improvements to the respective processes so that the end-of-line processes can be accelerated and / or performed with higher energy efficiency without compromising on performance, capacity or lifespan of the battery cells.

[0023] In the context of the present disclosure, the terms “in-line” and “in-situ” are used interchangeably, and refer to the arrangement of a sensor in a process. An “in-line” or “in-situ” acquisition of a battery parameter refers to the observation, measurement or estimation of a battery parameter which is integrated directly into the process. This is in contrast to an “online” acquisition, wherein the observation, measurement or estimation of a battery parameter is taken from a separate area adjacent to the process line, and an “at-line” acquisition or “off-line” acquisition, wherein the observation, measurement or estimation of a battery parameter is performed outside of a process line, for example, in a laboratory.

[0024] The nature of at-line or off-line analyses is such that automatic control based on those parameters is difficult due to the time delay in obtaining the parameter, and requires the parameter to be manually entered back into the system so that requisite adjustments to process parameters can be carried out. On the other hand, in-line / in-situ measurements have the advantage of real-time acquisition of a battery parameter, and automatic control or closed-loop control can be carried out based on said real-time acquisition.

[0025] Reference will be made to Fig. 1, which shows a flowchart of a typical manufacturing process 100 containing a number of sub-processes. Particularly, the manufacturing process 100 shows only the portion of a battery manufacturing process after which the battery cells have been formed and assembled. The manufacturing process 100 may be considered as an end-of-line process to be carried out at the end of the line for the manufacture of battery cells, and includes sub-processes related to quality control and battery cell conditioning prior to the battery cells leaving the manufacturing facility. The battery cells enter the manufacturing process 100 after being fully manufactured, filled with electrolyte, and sealed. During the manufacturing process 100, the battery cells are subjected to one or more formation processes and one or more aging processes to condition the battery cells and ensure the required performance, capacity and lifespan characteristics.

[0026] Battery cells entering the manufacturing process 100 first arrive at the inspection and identification sub-process 110, in which each battery cell or batch of battery cells are provided with an ID and the initial inspections are carried out.

[0027] After the battery cells are identified and inspected, a first aging process may be carried out. An “aging process” involves repeated charge / discharge cycles at different rates, including periods of rest time, and under certain environmental conditions, according to an aging routine. In the exemplarily-shown manufacturing process 100, the battery cells are subjected to an ambient aging process 120 in which the battery cells are cycled under ambient temperature conditions.

[0028] In the next stage of the manufacturing process 100, the battery cells are subjected to the formation process 130. A “formation process” involves precisely and slowly charging and discharging the battery cell according to a formation routine to build up the solid electrolyte interphase (SEI) layer on the electrodes within the battery cell. The SEI layer is crucial to battery performance, capacity and lifespan.

[0029] In the next stage of the manufacturing process 100, additional aging processes may be carried out. The battery cells may be subjected to a high temperature aging process 140 in which the battery cells are cycled according to an aging routine under high temperature conditions. Finally, the battery cells are subjected to an EOL testing process 150 in which various tests are carried out, such as open-circuit voltage (OC V) testing, automatic charging relay (ACR) testing and the like, before sorting 160 in which the battery cells are sorted or “binned” according to quality data generated during the manufacturing process 100.

[0030] Aspects and embodiments of the present disclosure are related to methods and apparatus for the formation process 130 and the aging processes 120, 140. The remaining sub-processes exemplarily shown in manufacturing process 100 may be carried out according to typical methods known in the current state of the art.

[0031] Reference will now be made to Fig. 2, which shows a schematic view of a formation / aging apparatus 200 in which at least one battery cell B, particularly a plurality of battery cells B, is provided within a battery cell chamber 210 and subjected to a formation process and / or an aging process. Further reference will be made to Fig. 3, which shows a flowchart of a formation / aging method 300 according to aspects and embodiments of the present disclosure.

[0032] According to a first aspect of the present disclosure, a method 300 for battery cell formation and / or aging during battery cell manufacturing is provided. The formation / aging method 300 includes providing at least one battery cell B in a battery cell chamber 210, the battery cell chamber 210 including at least one sensor configured for acquiring a battery cell parameter of the at least one battery cell B. Next, the formation / aging method 300 includes charging and / or discharging the at least one battery cell according to a battery cell formation process and / or a battery cell aging process.

[0033] As exemplarily shown in the flowchart of Fig. 3, the formation / aging method 300 begins with the providing 310 of the at least one battery cell B into the battery cell chamber 210. The method 300 corresponds to one of the aging process 120, 140 or formation process 120 as identified above as part of the manufacturing process 100. Accordingly, the at least one battery cell B may have previously come from, for example, the inspection and identification sub-process 110, or from a previous aging process 120, 140 or formation process 130. Further, the at least one battery cell B is provided into the battery cell chamber 210 after already being assigned an ID.

[0034] The at least one battery cell B is then subjected to charging and / or discharging 320 according to a battery cell formation process and / or a battery cell aging process. The respective process, be it a formation process or an aging process, is controlled by a set of parameters P which may be stored as process parameters 360. The process parameters 360, comprising a set of parameters P, may be provided by an external storage system 370 which may be included in an overall system controller which controls the manufacturing process 100.

[0035] During or after the charging and / or discharging 320, a battery cell parameter S is acquired by the at least one sensor in the acquiring 330 step. The battery cell parameter S may correspond to a raw signal from the at least one sensor which is transmitted to, for example, the controller 250, or may correspond to a pre-processed signal.

[0036] After the acquiring 330 of the battery cell parameter S, which may have been acquired during or after the charging and / or discharging 320, a level of quality Q is determined in the determining 340 step. The determining 340 may be carried out by the controller 250 based on the battery cell parameter S, i.e. the raw signal or the pre-processed signal provided by the at least one sensor. In particular, the level of quality Q corresponds to a level of SEI formation which has occurred within the at least one battery B during or after charging and / or discharging 320 in the formation / aging process 300.

[0037] Finally, the at least one battery cell B is output from the formation / aging method 300 at output 380. The output 380 from the formation / aging method 300 may include one of an aging process 120, 140, a formation process 130 or the subsequent EOL testing 150 according to the manufacturing process 100. Optionally, the formation / aging method 300 may include providing the level of quality Q, which is associated with the at least one battery cell B having a specific ID, to the external storage system 370 as quality data. The quality data stored may be used at a later stage in the manufacturing process 100, such as for adjusting the process parameters P of a subsequent aging process 120, 140 or a subsequent formation process 130, or for the sorting 160 where the battery cells are sorted or “binned” according to the level of quality Q.

[0038] As optionally shown in the flowchart of Fig. 3, the formation / aging method 300 according to the first aspect may be a closed-loop feedback control of the charging and / or discharging of the battery cell based on the battery cell parameter acquired by the at least one sensor. According to an embodiment, which may be combined with other embodiments described herein, the acquiring 330 of the battery cell parameter S is performed simultaneously with the charging and / or discharging 320 of the at least one battery cell B, and the charging and / or discharging 320 of the at least one battery cell B is adjusted 350 based on the battery cell parameter using a predetermined formation model and / or a predetermined aging model. Particularly, as exemplarily shown, the level of quality Q which is determined may be used in the adjusting 350 so that, based on a predetermined model, an adjusted process parameter AP is generated and provided to the set of process parameters 360 so that the charging and / or discharging 320 can be controlled in a closed-loop fashion.

[0039] By implementing a closed-loop control scheme for the formation and / or aging process, the formation / aging method 300 can be adapted more quickly and in real-time based on the level of quality, for example the level of SEI formation in the battery cell. For example, based on the level of SEI formation determined by the controller 250, one or more process parameters P such as a charging current, a charging / discharging rate or a charging voltage may be adjusted accordingly based on a formation / aging model. Such a closed-loop control scheme allows for the formation / aging process to be optimised, in particular accelerated, without compromising the performance, capacity or lifespan of the resulting battery cell.

[0040] Further to the determining 340 of the level of quality Q, the formation / aging method 300 may further include an optional classification step wherein the level of quality Q is compared to a target level of quality. According to an embodiment, which may be combined with other embodiments described herein, the method 300 further includes comparing the level of quality to at least one predetermined threshold, and classifying the at least one battery cell B based on the comparing. Preferably, the at least one battery cell B is classified as defected if the level of quality Q is below the at least one predetermined threshold. More preferably, the at least one battery cell is given a quality rating if the level of quality is within a plurality of predetermined ranges.

[0041] Although the above-described classification step may be performed in a subsequent testing step in the manufacturing process 100, such as in the EOL testing 150 or the sorting 160, the classification being performed during the aging process 120, 140 and / or the formation process 130 allows for a defective battery cell B to be identified earlier in the manufacturing process 100. For example, if the level of quality Q indicates, before formation is complete, that a battery cell B will not reach a target level of SEI formation, the charging and / or discharging 320 may be halted and the battery cell B may be marked as defective. Thus, the additional time and energy associated with formation or aging of a defective battery can be avoided, improving the overall efficiency of the manufacturing process 100.

[0042] In the formation / aging method 300 according to the present disclosure, the acquiring 330 of battery cell parameter S by at least one sensor, combined with the determining 340 of a level of quality Q, is based on the detection of one or more gas events occurring within the at least one battery cell B. According to an embodiment, which may be combined with other embodiments described herein, the at least one sensor is configured to detect one or more gas events corresponding to the generation of one or more gases in the at least one battery cell and / or a venting from the at least one battery cell.

[0043] In the context of the present disclosure, the term “gas event” refers to the generation of gases within a battery cell during formation and / or aging. Such a gas event may merely result in gas being generated which remains within the battery cell, or may result in the venting of said gas into the battery cell chamber 210. A gas event may correspond to either an instantaneous event, such as the start of gas generation, or may correspond to an event with a duration, such as the generation of gas over a period of time. Depending on the signals sensed by the at least one sensor, various parameters of the gas events occurring within the battery cell may be determined.

[0044] One or more gas events occurring within the battery cell may correspond to bubbles of gas being generated within the at least one battery cell B. Gas generated in this manner may occur during SEI formation, and the gas generation generates a distinct acoustic signal which originates from the battery cell B, which may be detected by at least one acoustic sensor 220 provided within the battery cell chamber 210. Based on, for example, the amplitude, duration or timing of the generation of the acoustic signal, the level of quality, particularly the level of SEI formation which has occurred within the battery cell B, may be determined in-situ.

[0045] Similarly, the one or more gas events occurring within the battery cell may correspond to a volume of gas being vented from the at least one battery cell B into the battery cell chamber 210. Similar to the gas generation described above, gas venting also generates a distinct acoustic signal which originates from the battery cell B, and based on the signal detected by at least one acoustic sensor 220, a level of quality, particularly the level of SEI formation, may be determined. Alternatively, or additionally, to the acoustic sensing by at least one acoustic sensor 220, the gas venting may be detected by a gas sensor 230 which is configured to sense the gas vented from the battery cell B. The gas sensor 230 may, for example, be configured to measure a volume of the gas being vented, a rate of gas being vented, or whether the gas corresponds to certain gas species. Based on such parameters of the vented gas, a level of quality, particularly a level of SEI formation, may be determined in-situ.

[0046] In both cases where the at least one sensor includes an acoustic sensor 220 and / or a gas sensor 230, since the battery parameters may be sensed in-situ, this allows for improved control over the formation / aging method 300, such as by implementing a closed-loop control scheme.

[0047] The level of quality Q may correspond to a variety of quality parameters which may be determined based on the battery cell parameter S acquired by the at least one sensor. According to an embodiment, which may be combined with other embodiments described herein, the level of quality Q corresponds to at least one of the group consisting of a level of solid electrolyte interphase formation, a level of electrolyte decomposition, a level of lithium consumption during the formation process, a level of charge for the formation process, a quality of battery cell housing quality, particularly a quality of welding and / or sealing of the battery cell housing, an indication that the at least one battery cell is defective, a battery cell capacity, a battery cell resistance, and a battery cell cycle performance. However, the present disclosure is not limited thereto, and other measures of quality may be determined based on the battery cell parameters which may be detected by an acoustic sensor 220 and / or a gas sensor 230.

[0048] As an example, the level of quality Q may correspond to the level of solid electrolyte interphase (SEI) formation. Based on the detection of one or more gas events by an acoustic sensor 220, which indicate that gas is being generated within the battery cell B, the level of SEI formation may be determined based on, for example, the duration from the start of the gas event. Further, the level of SEI formation may be indicated by the detection of a gas venting, as the amount of gas which is expected to be generated before pressure builds sufficiently to vent into the battery cell chamber 210 can correspond to a level of SEI formation.

[0049] As a further example, the level of quality Q may correspond to the quality of a welding and / or sealing of the battery cell housing. During SEI formation, an amount of gas is generated before building up within the battery cell and reaching a threshold where the gas begins to be vented. This venting may be controlled, for example, with a gas vent in the battery cell housing which only opens when a certain threshold is reached. In the case where an acoustic sensor 220 detects a start of gas generation and, before an expected amount of gas is generated, a gas venting is detected by an acoustic sensor 220 or a gas sensor 230, it may be determined that the battery cell B is venting gas too soon, which may indicate a failure of a weld or seal of the battery cell housing.

[0050] In the case where the at least one sensor includes an acoustic sensor 220, a variety of battery cell parameters may be detected. For example, the acoustic sensor 220 may detect an acoustic signal generated at the start of a gas event, and further acoustic signals generated with ongoing gas generation, and the at least one battery parameter S can be based on this detection. According to an embodiment, which may be combined with other embodiments described herein, the at least one sensor includes an acoustic sensor 220 configured for acquiring the battery cell parameter corresponding to properties of an acoustic wave generated by the gas event. The level of quality Q is based on at least one battery cell parameter S from the group consisting of a time since the start of the formation process and / or aging process, a time since the end of the formation process and / or aging process, a cell voltage measured at the start of the formation process and / or aging process, a cell voltage measured at the end of the formation process and / or aging process, a total number of gas events, a frequency of gas events, an amplitude of the acoustic wave, a duration of the acoustic wave, and a frequency of the acoustic wave. However, the present disclosure is not limited thereto, and other parameters which may be acquired from the acoustic signal may also be relevant to the determination of the level of quality.

[0051] Similarly, in the case where the at least one sensor includes a gas sensor 230, a variety of battery cell parameters may be detected. For example, the gas sensor 230 may detect the presence of a vented gas, a volume of vented gas, or a species of vented gas, and may further detect ongoing gas venting, and at least one battery parameter S can be based on this detection. According to an embodiment, which may be combined with other embodiments described herein, the at least one sensor comprises a gas sensor configured for acquiring the battery cell parameter corresponding to properties of a gas vented into the battery cell chamber by a gas event. The level quality Q is based on the battery cell parameter S corresponding to at least one of the group consisting of a presence of the gas, a time since the start of the gas event, a time since the end of the gas event, a cell voltage measured at the start of the gas event, a cell voltage measured at the end of the gas event, a volume of the gas, a rate of venting of the gas, a presence of a specific organic or inorganic compound in the gas, and a composition of the gas. However, the present disclosure is not limited thereto, and other parameters which may be acquired from the detection of the vented gas may also be relevant to the determination of the level of quality. Preferably, the gas sensor 230 is configured for in-situ acquisition of the at least one battery cell parameter S.

[0052] In particular, the detection of specific gas species within the gas being vented from the at least one battery cell B may be a strong indicator of the level of quality, particularly the level of SEI formation, which is occurring within the battery cell B. According to a further embodiment, the battery cell parameter S corresponds to the presence, volume and / or rate of hydrogen (H2), methane (CH4), ethylene (C2H4), propylene (C3H6), carbon monoxide (CO), and / or carbon dioxide (CO2) in the gas vented into the battery cell chamber 210. Such compounds are known by-products of SEI formation, and by detecting their presence in the vented gas, an accurate determination of the level of SEI formation is possible. Particularly, if these gas species are detected by a gas sensor 230 capable of in-situ acquisition, the level of SEI formation can be determined in real-time. Furthermore, although aspects and embodiments of the present disclosure allow for the provision of an acoustic sensor 220 or a gas sensor 230, there are further synergistic advantages when an acoustic sensor 220, or a plurality of acoustic sensors 220, are provided in combination with a gas sensor 230. Since the process of SEI formation and the corresponding gas generation starts occurring before any gas may be vented into the battery cell chamber 210, the combination of acoustic sensors 220 and gas sensors 230 allows for an approximate determination of the level of SEI formation occurring within the battery cell B prior to gas venting, i.e. based on the acoustic signals generated within the battery cell B, and then allows for a more accurate determination of the level of SEI formation once gas venting has begun, i.e. based on the acoustic signals generated by the venting and based on the properties of the gas being vented. Accordingly, more fine-tuned formation and / or aging can be carried out. Further, in the case where a closed-loop control scheme is implemented, the adjustable charging and / or discharging may be adapted not only based on the vented gas detected by the gas sensor 230, but also on the gas generation within the battery cell detected by the acoustic sensors 220. Further advantages may arise when using multiple acoustic sensors 220, as the origin of the vented gas which is detected by the gas sensor 230 may be localised based on one or more methods of localisation which are possible through, for example, triangulation or position-based acoustic sensing, which will be described in further embodiments below.

[0053] Further to the method described according to the above first aspect, an apparatus 200 for battery cell formation and / or aging is provided according to the second aspect. The formation / aging apparatus 200 includes a battery cell chamber 210 configured for accommodating at least one battery cell B therein, at least one sensor configured for detecting a battery cell parameter S of the at least one battery cell B, a controllable charging unit 240 configured for charging and / or discharging the at least one battery cell B, and a controller configured for controlling the charging of the at least one battery cell B. The controlling may be carried out according to a battery cell formation process and / or a battery cell aging process by controlling the controllably charging unit 240 and monitoring the battery cell parameter S detected by the at least one sensor. The at least one sensor includes an acoustic sensor 220 and / or a gas sensor 230.

[0054] During the formation process and / or the aging process, the at least one battery cell B is provided within a battery cell chamber 210. In the most basic form, the battery cell chamber 210 provides a respective position for each one of the at least one battery cell B, such that the battery cell chamber 210 defines a volume in which the at least one battery B is subjected to formation and / or aging.

[0055] According to one arrangement, the battery cell chamber 210 may include a battery cell tray 240 on which the at least one battery cell B is positioned, the battery cell tray 240 forming the floor of the battery cell chamber 210, and an upper chamber portion, forming the walls and roof, which is placed over the battery cell tray 240 to enclose the at least one battery cell B. Alternatively, the battery cell tray 240 may be configured to slide the battery cell chamber 210 through a chamber door, which may be closed to enclose the at least one battery cell B. The battery cell tray 240 may be further realised as a carrier which is configured for transporting the at least one battery cell B between one or more EOL process apparatus and / or one or more battery cell chambers 210.

[0056] Preferably, the battery cell chamber 210 may be sealed, such that the internal volume of the battery cell chamber 210 is isolated from the atmosphere. In the case where the at least one sensor includes an acoustic sensor, a sealed internal volume allows for acoustic signals to be acquired only from the at least one battery cell B within the battery cell chamber 210 without external disturbances. Similarly, in the case where the at least one sensor includes a gas sensor, a sealed internal volume allows for vented gas to be detected only from the at least one battery within the battery cell chamber 210. In other words, a sealed internal volume isolates the at least one sensor from external disturbances, such as acoustic signals or vented gas originating from a neighbouring battery cell chamber 210 in a formation / aging stack.

[0057] Further, the battery cell chamber 210 may be configured for temperature isolation and / or fire suppression. In the case of a battery fault which results in excessive temperature or a fire, the battery cell chamber 210 may prevent temperature or fire from spreading to other battery cell chambers 210 in a formation / aging stack.

[0058] The formation / aging apparatus 200 includes at least one sensor configured for detecting a battery cell parameter of the at least one battery cell B, wherein the at least one sensor includes an acoustic sensor 220 and / or a gas sensor 230. Particularly, the at least one sensor is provided within the battery cell chamber 210 so that signals generated by the at least one battery cell B, i.e. acoustic signals originating from the at least one battery cell B and / or gas vented from the at least one battery cell B, may be detected. The at least one sensor, i.e. the acoustic sensor 220 and / or the gas sensor 230, is connected to the controller 250 so that signals detected by the at least one sensor may be acquired by the controller 250.

[0059] According to some embodiments described herein, the at least one sensor includes an acoustic sensor 220. As exemplarily shown in Fig. 2, the formation / aging apparatus 200 is provided with a single acoustic sensor 220 in a most basic form. However, according to certain embodiments, the at least one sensor may include a plurality of acoustic sensors 220, the embodiments of which will be described later. The acoustic sensor 220 may include any suitable sensor known in the current state of the art for detecting acoustic signals. Preferably, the acoustic sensor 220 may include an air-type microphone or a contact-type microphone. For example, the acoustic sensor 220 may be an air-type microphone provided within the internal volume of the battery cell chamber 210 to detect acoustic signals which propagate from the battery cells B through the internal volume to the microphone. Alternatively, the acoustic sensor 220 may be a contacttype microphone arranged so as to contact a battery cell B, or within the battery cell tray 240 beneath the battery cells B. The at least one sensor may include multiple acoustic sensors 220 of different types.

[0060] Further, the acoustic sensor 220 may include an additional signal processing unit for processing the signal detected by the acoustic sensor 220 before the signal is provided to the controller 250. For example, the signal processing unit may include a high-pass or low-pass filter.

[0061] According to some embodiments described herein, the at least one sensor includes a gas sensor 230. The gas sensor 230 may be configured for detecting a composition of a gas vented from the at least one battery cell B and, preferably, the gas sensor 230 is configured for in-situ acquisition. Preferably, the gas sensor 230 may be a volatile gas sensor. More preferably, the gas sensor 230 includes one of the group consisting of an infrared Raman spectrometer, an integrated mass spectrometer, an integrated gas chromatography, a photoionization sensor, a real-time electrochemical sensor, a laser absorption spectrometer, and a laser-induced fluorescence sensor. However, the present disclosure is not limited thereto, and any suitable gas sensor may be provided for detecting and / or analysing the vented gas, preferably in-situ.

[0062] The formation / aging apparatus 200 includes a controllable charging unit 240 configured for charging and / or discharging the at least one battery cell B. Accordingly, the controllable charging unit 240 includes a controllable power supply for providing a charging current to the at least one battery cell B and a controllable load for draining discharge current from the at least one battery cell B. The controllable charging unit 240 is electrically connected to each one of the at least one battery cells B, and may be in the form of any suitable controllable charging unit 240 known in the state of the art.

[0063] The formation / aging apparatus 200 further includes a controller 250 which is configured for controlling the charging and / or discharging of the at least one battery cell B. The controller 250 acquires one or more signals from the at least one sensor, such as the acoustic sensor 220 and / or the gas sensor 230. The controller 250 may be provided as a dedicated controller 250 for controlling the formation / aging process for the battery cells B within the battery cell chamber 210, or may be a system-level controller which is configured for controlling the formation / aging process for the battery cells B within multiple battery cell chambers 210. Accordingly, the controller 250 may be attached to or integrated within battery cell chamber 210, or may be arranged at a location remote from the battery cell chamber 210.

[0064] According to an embodiment, which may be combined with other embodiments described herein, controller 250 may be configured for carrying out the method 400 according to the aspects and embodiments described herein.

[0065] Controller 250 may be controllably connected to the controllable charging unit 240, such that the controller 250 may adjust at least one process parameter of the charging / discharging of the battery cells B.

[0066] Further, although the controllable charging unit 240 and the controller 250 are exemplarily shown as being separate elements, the present disclosure is not limited thereto and the controller charging unit 240 may be integrated with controller 250 in a single unit.

[0067] The controller 250 of apparatus 200 may be a microprocessor, a programmable logic controller (PLC), or a digital signal processor (DSP). Particularly, the controller 250 may include a processing element, at least one input and at least one output, such that a data processing operation is performed on the at least one input and output to the at least one output. The controller 250 may further include at least one storage means, which may include random access memory (RAM), read-only memory (ROM) and external data storage means such as hard disks, flash storage or network-attached storage, and may further include a network interface for connecting the controller 250 to a data network, in particular a global data network. For example, the controller 250 may be further configured to transmit at least one quality parameter, such as a level of SEI formation for a specific battery cell B or for a batch of battery cells B, to a central quality control system such that the respective battery cell B or batch of battery cells B may be sorted or binned according to said quality parameter.

[0068] According to further embodiments of the present disclosure, the formation / aging apparatus may be provided with a plurality of acoustic sensors which may provide further advantages. For example, the formation / aging apparatus may be provided with multiple acoustic sensors so that the origin of certain acoustic signals and / or vented gases may be identified, such that parameters may be identified in specific battery cells B of the plurality of battery cells B provided in the battery cell enclosure.

[0069] Referring now to Fig. 4, an alternative arrangement for a formation / aging apparatus 400 according to embodiments and aspects of the present disclosure is shown. An exemplary battery tray 440 is shown, which is intended to replace the battery tray 240 as shown in Fig. 2. For clarity, the other components of the formation / aging apparatus are not shown.

[0070] According to a further embodiment of the formation / aging apparatus of the second aspect, the at least one battery cell comprises a plurality of battery cells Ba-Bd, and the at least one sensor includes a plurality of acoustic sensors 420a-420d arranged at a plurality of sensing positions 430a-430d within the battery cell chamber 210. Preferably, the number and position of the acoustic sensors 420a-420d corresponds to the number and position of the plurality of battery cells Ba-Bd, respectively.

[0071] As exemplarily shown in Fig. 4, the plurality of acoustic sensors 420a-420d are each provided in the battery tray 440 below each respective battery cell Ba-Bd. Particularly, each battery cell Ba-Bd is provided with a corresponding acoustic sensor 420a-420d. When a gas event occurs within one or more of the battery cells Ba-Bd, the amplitudes of the acoustic signal detected by the respective acoustic sensor 420a-420d are different, and the specific location of the origin of the acoustic signal can be determined. Further, in the case where each acoustic sensor 420a- 420d includes a contact microphone, the acoustic signal can be even more clearly distinguished. By comparing the respective amplitudes of each of the acoustic sensors 420a, 420d, it can be determined in which specific battery cell Ba-Bd the gas event occurred.

[0072] As exemplarily shown in the figure, the plurality of acoustic sensors 420a-420d are provided in the battery tray 440. However, other arrangements of acoustic sensors within the battery cell chamber 210 are possible. Alternatively, the plurality of acoustic sensors may include at least three acoustic sensors arranged at three different spatial positions within the battery cell chamber 210. With this arrangement, when an acoustic signal is detected which corresponds to a gas event occurring within one of the battery cells B, the at least three respective signals detected by the at least three acoustic sensors may be triangulated so that the origin of the gas event can be identified. The triangulation could be based on, for example, comparing the respective amplitudes of the detected signals, or the respective times of flight of the detected signals.

[0073] Accordingly, the formation / aging method 300 according to the first aspect may also be extended according to the following further embodiments.

[0074] According to a further embodiment of the formation / aging method 300 of the first aspect, the at least one battery cell B includes a plurality of battery cells Ba-Bd and the at least one sensor includes at least three acoustic sensors 420a-420d configured for detecting an acoustic wave generated by the gas event. Each one of the at least three acoustic sensors 420a-420d is positioned at predetermined positions 430a-430d within the battery cell chamber 210. The method 300 further includes determining in which specific one of the plurality of battery cells B the gas event has occurred based on the detection of the acoustic wave by each of the at least three acoustic sensors 420a-420d.

[0075] Particularly, the formation / aging method 300 may include specific methods of localising the origin of the gas event. According to a further embodiment of the formation / aging method 300 of the first aspect, the determining of the specific one of the plurality of battery cells is based on at least one of three determinations.

[0076] The determining may be based on assigning each one of the plurality of acoustic sensors 420a- 420d to a respective one of the plurality of battery cells Ba-Bd, preferably wherein the number and position of the respective acoustic sensors 420a-420d corresponds to the number and position of the respective battery cells Ba-Bd, more preferably wherein one acoustic sensor 420a-420d is positioned beneath each respective battery cell Ba-Bd. The determining may alternatively be based on comparing the respective amplitudes of the acoustic signal detected by each one of the plurality of acoustic sensors 420a-420d. The determining may be still alternatively based on the respective times of flight of the acoustic signal detected by the plurality of acoustic sensors 420a-420d, wherein the plurality of acoustic sensors 420a-420d includes at least three acoustic sensors.

[0077] Although various exemplary embodiments of the invention have been disclosed, it will be apparent to those skilled in the art that various changes and modifications can be made which will achieve some of the advantages of the invention without departing from the spirit and scope of the invention. It will be obvious to those reasonably skilled in the art that other components performing the same functions may be suitably substituted. It should be mentioned that features explained with reference to a specific figure may be combined with features of other figures, even in those cases in which this has not explicitly been mentioned.

[0078] Spatially relative terms such as “under”, “below”, “lower”, “over”, “upper” and the like are used for ease of description to explain the positioning of one element relative to a second element. These terms are intended to encompass different orientations of the device in addition to different orientations than those depicted in the figures. Further, terms such as “first”, “second”, and the like, are also used to describe various elements, regions, sections, etc. and are also not intended to be limiting. Like terms refer to like elements throughout the description. As used herein, the terms “having”, “containing”, “including”, “comprising” and the like are open ended terms that indicate the presence of stated elements or features, but do not preclude additional elements or features. The articles “a”, “an” and “the” are intended to include the plural as well as the singular, unless the context clearly indicates otherwise. With the above range of variations and applications in mind, it should be understood that the present invention is not limited by the foregoing description, nor is it limited by the accompanying drawings. Instead, the present invention is limited only by the following claims and their legal equivalents.

[0079] Reference numbers

[0080] 100 Manufacturing process 320 Charging and / or discharging

[0081] 110 Inspection and identification 330 Acquiring the battery cell

[0082] 120 Ambient aging process parameter

[0083] 130 Formation process 340 Determining a level of quality

[0084] 140 High-temperature aging process 350 Adj usting the charging and / or

[0085] 150 EOL testing discharging

[0086] 160 Sorting 360 Set of process parameters

[0087] 200, 400 Formation / aging apparatus 370 External storage system

[0088] 210 Battery cell chamber 380 Output

[0089] 220 Acoustic sensor 420a-d Acoustic sensor

[0090] 230 Gas sensor 430a-d Battery cell position

[0091] 240 Battery cell tray 440 Battery cell tray

[0092] 250 Controller B, Ba-d Battery cell

[0093] 260 Controllable charging unit ID Battery identifier

[0094] 300 Method for battery cell Q Level of quality formation / aging P Process parameter

[0095] 310 Providing at least one battery AP Adjusted process parameter cell in a battery cell chamber S Battery cell parameter

Claims

Claims1. Method (300) for battery cell formation and / or aging during battery cell manufacturing comprising:Providing (310) at least one battery cell (B) in a battery cell chamber (210), the battery cell chamber (210) comprising at least one sensor configured for acquiring a battery cell parameter (S) of the at least one battery cell (B); charging and / or discharging (320) the at least one battery cell (B) according to a battery cell formation process and / or a battery cell aging process; acquiring (330) the battery cell parameter (S) using the at least one sensor; and determining (340) a level of quality (Q) based on the battery cell parameter (S), wherein the at least one sensor comprises an acoustic sensor (220) and / or a gas sensor (230).

2. The method (300) according to claim 1, wherein the at least one sensor is configured to detect one or more gas events corresponding to the generation of one or more gases in the at least one battery cell (B) and / or a venting from the at least one battery cell (B).

3. The method (300) according to any one of claims 1 to 2, further comprising: comparing the level of quality (Q) to at least one predetermined threshold; and classifying the at least one battery cell (B) based on the comparing, preferably wherein the at least one battery cell (B) is classified as defective if the level of quality (Q) is below the at least one predetermined threshold, and / or the at least one battery cell (B) is given a quality rating if the level of quality (Q) is within a plurality of predetermined ranges.

4. The method (300) according to any one of claims 1 to 3, wherein the level of quality (Q) corresponds to at least one of the group consisting of: a level of solid electrolyte interphase (SEI) formation; a level of electrolyte decomposition; a level of lithium consumption during the formation process; a level of charge for the formation process a battery cell housing quality, particularly a quality of welding and / or sealing of the battery cell housing; an indication that the at least one battery cell (B) is defective; a battery cell capacity; a battery cell resistance; and a battery cell cycle performance.

5. The method (300) according to any one of claims 1 to 4, wherein: the acquiring (330) of the battery cell parameter (S) is performed simultaneously with the charging and / or discharging (320) of the at least one battery cell (B); and the charging and / or discharging (320) of the at least one battery cell (B) is adjusted (350) based on the battery cell parameter (S) using a predetermined formation model and / or a predetermined aging model.

6. The method (300) according to any one of claims 2 to 5, wherein: the at least one sensor comprises an acoustic sensor (220) configured for acquiring the battery cell parameter (S) corresponding to properties of an acoustic wave generated by the gas event; andthe level of quality (Q) is based on at least one battery cell parameter (S) from the group comprising: a time since the start of the formation process and / or aging process; a time since the end of the formation process and / or aging process; a cell voltage measured at the start of the formation process and / or aging process; a cell voltage measured at the end of the formation process and / or aging process; a total number of gas events; a frequency of gas events; an amplitude of the acoustic wave; a duration of the acoustic wave; and a frequency of the acoustic wave.

7. The method (300) according to any one of claims 2 to 6, wherein: the at least one battery cell (B) comprises a plurality of battery cells (Ba-Bd); the at least one sensor comprises at least three acoustic sensors (420a-420d) configured for detecting an acoustic wave generated by the gas event, each one of the at least three acoustic sensors (420a-420d) being positioned at predetermined positions within the battery cell chamber (210); and determining in which specific one of the plurality of battery cells (Ba-Bd) the gas event has occurred based on the detection of the acoustic wave by each of the at least three acoustic sensors (420a-420d).

8. The method (300) according to claim 7, wherein the determining of the specific one of the plurality of battery cells (Ba-Bd) is based on at least one of:assigning each one of the plurality of acoustic sensors (420a-420d) to a respective one of the plurality of battery cells (Ba-Bd), preferably wherein the number and position of the respective acoustic sensors (420a-420d) corresponds to the number and position of the respective battery cells (Ba-Bd), more preferably wherein one acoustic sensor is positioned beneath each respective battery cell; comparing the respective amplitudes of the acoustic signal detected by each one of the plurality of acoustic sensors (420a-420d); or triangulation based on the respective times of flight of the acoustic signal detected by the plurality of acoustic sensors (420a-420d), wherein the plurality of acoustic sensors comprises at least three acoustic sensors.

9. The method (300) according to any one of claims 2 to 5, wherein: the at least one sensor comprises a gas sensor (230) configured for acquiring the battery cell parameter (S) corresponding to properties of a gas vented into the battery cell chamber (210) by a gas event, preferably wherein the gas sensor (230) is configured for in- situ acquisition; and the level quality (Q) is based on the battery cell parameter (S) corresponding to at least one of the group comprising: a presence of the gas; a time since the start of the gas event; a time since the end of the gas event; a cell voltage measured at the start of the gas event; a cell voltage measured at the end of the gas event; a volume of the gas; a rate of venting of the gas;a presence of a specific organic or inorganic compound in the gas; and a composition of the gas.

10. The method (300) according to claim 9, wherein the battery cell parameter (S) corresponds to the presence, volume and / or rate of hydrogen (H2), methane (CH4), ethylene (C2H4), propylene (C3H6), carbon monoxide (CO), and / or carbon dioxide (CO2) in the gas vented into the battery cell chamber (210).

11. Apparatus (200, 400) for battery cell formation and / or battery cell aging, the apparatus (200, 400) comprising: a battery cell chamber (210) configured for accommodating at least one battery cell (B, Ba-Bd) therein; at least one sensor configured for detecting a battery cell parameter (S) of the at least one battery cell (B, Ba-Bd); a controllable charging unit (240) configured for charging and / or discharging the at least one battery cell (B, Ba-Bd); and a controller (250) configured for controlling a charging and / or discharging of the at least one battery cell (B, Ba-Bd) according to a battery cell formation process and / or a battery cell aging process by controlling the controllable charging unit (240) and by monitoring the battery cell parameter (S) detected by the at least one sensor, wherein the at least one sensor comprises an acoustic sensor (220, 420a-420d) and / or a gas sensor (230).

12. The apparatus (400) according to claim 11, wherein the at least one battery cell comprises a plurality of battery cells (Ba-Bd), andthe at least one sensor includes a plurality of acoustic sensors (420a-420d) arranged at a plurality of sensing positions (430a-430d) within the battery cell chamber (210), preferably wherein the number and position of the plurality of acoustic sensors (420a- 420d) corresponds to the number and position of the plurality of battery cells (Ba-Bd), respectively.

13. The apparatus (200, 400) according to any one of claims 11 to 12, wherein the at least one sensor comprises a gas sensor (230) configured for detecting a composition of a gas vented from the at least one battery cell (B, Ba-Bd), preferably wherein the gas sensor (230) is configured for in-situ acquisition, more preferably wherein the gas sensor (230) comprises one of the group consisting of: an infrared Raman spectrometer; an integrated mass spectrometer; an integrated gas chromatography; a photoionization sensor; a real-time electrochemical sensor; a laser absorption spectrometer; and a laser-induced fluorescence sensor.

14. The apparatus (200, 400) according to any one of claims 11 to 13, wherein the controller (250) is configured for carrying out the method (300) according to any one of claims 1 to 10.