Method for analyzing the quality of battery cells

Abstract

A method for analyzing the quality of battery cells includes performing a high-throughput quality inspection on the battery cells using a quality control system, evaluating a quality score for the battery cells, wherein the quality score identifies the battery cells as low quality or high quality, and if identified as low quality, performing a full quality inspection on the battery cells. The method also includes evaluating an enhanced quality score for the battery cells, replacing the quality score of the quality control system, identifying the battery cells as confirmed low quality or confirmed high quality, and if confirmed as low quality, providing modified production instructions for manufacturing subsequent battery cells.

Description

Technical Field

[0001] The present disclosure relates to a method of analyzing the quality of a battery cell, and more particularly, to a method of analyzing the quality of a battery cell by performing a comprehensive quality inspection on a battery cell evaluated as having low quality in a high-throughput quality inspection. Background Art

[0002] The use of electric motors to power vehicles has grown exponentially in recent years. To power these electric motors, battery packs consisting of multiple battery cells are used. Most battery cells can maintain a charge sufficient to power a vehicle over a range of several hundred miles. However, low-quality battery cells are occasionally produced that fail to maintain an adequate charge. A common cause of low-quality battery cells is an inadequate solid electrolyte interface (SEI) deposited on the battery cell's anode. The SEI forms from the reduction of electrolyte solvents, additives, and salts.

[0003] Current practices for analyzing the quality of battery cells include performing discharge capacity checks (i.e., checking that the capacity provided by the (battery) cell (measured in ampere-hours) is within established specifications) and performing inventory maintenance and open circuit voltage (OCV) monitoring (which involves maintaining inventory and checking for decreases in OCV over time). While effective, such quality control measures are time-intensive (with the potential for large quality spills and the additional overhead cost of storing inventory) and the data is poor (i.e., not diagnostic or predictive). Other methods of analyzing battery cell quality involve analyzing the SEI on the anode. However, the battery cell must be cut open (destroying the battery cell) to analyze the SEI.

[0004] Therefore, while current quality control systems for analyzing the quality of battery cells achieve their intended purpose, a new method of analyzing the quality of battery cells is needed to address these issues. Summary of the Invention

[0005] According to several aspects of the present disclosure, a method for analyzing the quality of battery cells includes performing a high-throughput quality inspection on the battery cells using a quality control system, evaluating a quality score for the battery cells, wherein the quality score identifies the battery cells as low quality or high quality, and if identified as low quality, performing a full quality inspection on the battery cells. The method also includes evaluating an enhanced quality score for the battery cells, replacing the quality score of the quality control system, identifying the battery cells as confirmed low quality or confirmed high quality, and if confirmed as low quality, providing modified production instructions for manufacturing subsequent battery cells.

[0006] In one aspect, performing high-throughput quality inspection on battery cells using a quality control system is further defined as one of analyzing cell-formed charge data of the battery cells, analyzing a volume of gas within an air pocket of the battery cells, analyzing a composition of the gas within the air pocket, and analyzing discharge inspection data of the battery cells.

[0007] In another aspect, the quality control system is further defined as a first quality control system, and the quality score is further defined as a first quality score, the method further comprising performing a high-throughput quality inspection on the battery cell with a second quality control system, the second quality control system further defined as analyzing one of cell-formed charge data of the battery cell, analyzing a volume of gas within an air pocket of the battery cell, analyzing a composition of the gas within the air pocket, and analyzing discharge inspection data of the battery cell not performed by the first quality control system, and evaluating a second quality score of the battery cell, wherein the second quality score identifies the battery cell as low quality or high quality.

[0008] In another aspect, the method further includes analyzing the first quality score and the second quality score and evaluating a global quality score that identifies the battery cell as low quality or high quality.

[0009] In another aspect, evaluating the global quality score occurs before performing a comprehensive quality inspection of the battery cells.

[0010] In another aspect, performing high-throughput quality inspection on the battery cells with the first quality control system is further defined as analyzing cell-formed charge data of the battery cells, and wherein performing high-throughput quality inspection on the battery cells with the second quality control system is further defined as analyzing a composition of the gas within the gas bag, wherein analyzing the cell-formed charge data of the battery cells occurs before analyzing the composition of the gas within the gas bag.

[0011] In another aspect, performing high-throughput quality inspection on battery cells using a first quality control system is further defined as analyzing cell-formed charge data of the battery cells, and wherein performing high-throughput quality inspection on battery cells using a second quality control system is further defined as analyzing the gas volume within the gas pockets of the battery cells, wherein analyzing the cell-formed charge data of the battery cells occurs before analyzing the gas volume within the gas pockets of the battery cells.

[0012] In another aspect, performing high-throughput quality inspection on the battery cells with the first quality control system is further defined as analyzing cell-formed charge data of the battery cells, and wherein performing high-throughput quality inspection on the battery cells with the second quality control system is further defined as analyzing battery cell discharge inspection data, wherein analyzing the cell-formed charge data of the battery cells occurs before analyzing the battery cell discharge inspection data.

[0013] In another aspect, if identified as low quality, performing a comprehensive quality check on the battery cell is further defined as performing a gas chromatography analysis on the gas within the air bag.

[0014] In another aspect, if identified as low quality, performing a comprehensive quality check on the battery cell is further defined as performing an accelerated cycle test (ACT) through aging and repeated charge and discharge cycles.

[0015] In another aspect, providing modified production instructions for manufacturing successive battery cells is further defined as providing instructions for adaptively configuring charging parameters if low quality is determined.

[0016] In another aspect, the method further includes reintroducing the battery cell into production if the battery cell is determined to be high quality.

[0017] In another aspect, the method further includes scrapping the battery cell if the battery cell is determined to be of low quality.

[0018] According to aspects of the present disclosure, a method for analyzing the quality of a battery cell includes performing a high-throughput quality check on the battery cell with a first quality control system, evaluating a first quality score of the battery cell, wherein the first quality score identifies the battery cell as low quality or high quality, performing a high-throughput quality check on the battery cell with a second quality control system, and evaluating a second quality score of the battery cell, wherein the second quality score identifies the battery cell as low quality or high quality. The method also includes analyzing the first quality score and the second quality score, evaluating a global quality score that identifies the battery cell as low quality or high quality, performing a comprehensive quality check on the battery cell if the battery cell is identified as low quality, evaluating an enhanced quality score for the battery cell, replacing the quality score of the quality control system that identified the battery cell as confirmed low quality or confirmed high quality, and providing instructions for adaptively configuring charging parameters if the battery cell is identified as low quality.

[0019] In one aspect, evaluating the global quality score occurs before performing a full quality inspection on the battery cells.

[0020] In another aspect, if identified as low quality, performing a comprehensive quality check on the battery cell is further defined as performing a gas chromatography analysis on the gas within the air bag.

[0021] In another aspect, if identified as low quality, performing a full quality check on the battery cell is further defined as performing an ACT through aging and repeated charge and discharge cycles.

[0022] In another aspect, the method further includes scrapping the battery cell if the battery cell is determined to be of low quality.

[0023] According to several aspects of the present disclosure, a method for analyzing the quality of a battery cell includes analyzing cell charge data of the battery cell with a first quality control system, evaluating a first quality score of the battery cell, wherein the first quality score identifies the battery cell as low quality or high quality, analyzing a composition of gas within an air pocket of the battery cell with a second quality control system, and evaluating a second quality score of the battery cell, wherein the second quality score identifies the battery cell as low quality or high quality. The method also includes analyzing the first quality score and the second quality score, evaluating a global quality score identifying the battery cell as low quality or high quality, performing a comprehensive quality check on the battery cell if the battery cell is identified as low quality, evaluating an enhanced quality score for the battery cell, replacing the quality score of the quality control system that identified the battery cell as confirmed low quality or confirmed high quality, and providing instructions for adaptively configuring charging parameters if the battery cell is identified as low quality.

[0024] In one aspect, if identified as low quality, performing a comprehensive quality check on the battery cell is further defined as performing a gas chromatography analysis on the gas within the air bag.

[0025] Further areas of applicability will become apparent from the description provided herein.It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

[0027] Figure 1 is a perspective view of one example of a battery cell including an air bag, with the air bag in a deflated configuration.

[0028] Figure 2 yes Figure 1 A perspective view of a battery cell is shown with the air bag in the inflated configuration.

[0029] Figure 3is a flowchart of an example of a method for analyzing the quality of a battery cell. DETAILED DESCRIPTION

[0030] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses.

[0031] refer to Figure 1 and Figure 2 According to several aspects of the present disclosure, a battery cell is generally shown at 20. A battery cell 20 is a component of a battery pack. More specifically, a battery pack includes a plurality of battery cells 20 that are electrically connected. A common application for such battery cells 20 is in electric vehicles. However, the battery cells 20 can be used in many other applications, such as non-automotive vehicle applications, consumer electronics, etc. The battery cell 20 disclosed herein is a lithium-ion battery cell. The battery cell includes an electrolyte (not shown) and a pair of electrodes 22 including an anode and a cathode. The cathode can be NCM, NCMA, LMO, LFP, a combination thereof, or any similar material. The anode can include graphite, SiOx, Si, a combination thereof, or any similar material. The electrolyte can be a carbonate based on a lithium fluoride salt. However, battery cells of different chemistries can be utilized.

[0032] The battery cell 20 disclosed herein can undergo a number of steps to produce an active battery cell 20. Although the steps may vary between different types of battery cells, the battery cell 20 shown herein is produced by first preparing an electrode slurry (not shown) of active material, binder, and conductive agent mixed in specific mass ratios. Next, the electrode slurry is applied to a current collector and dried. During calendering, the electrode 22 is driven by rollers (not shown) to compress the porous electrode 22. The electrode 22 is then cut or punched into strips and wound or stacked together with a separator (not shown). The electrodes 22 (including the anode and cathode) are then placed in a casing 24 (more specifically, within the cavity defined by the casing 24). During the (battery) cell formation process, an electrolyte is injected into the cavity. The electrolyte penetrates and fills the pores within the electrode 22. Current is then applied to the electrode 22 by first applying a constant current to a predetermined first voltage limit, then applying a second constant current to a second voltage limit, and then maintaining the voltage at the second voltage limit for a predetermined length of time. When current is applied, the voltage drifts depending on the state of charge of the anode and cathode.

[0033] During the (battery) cell formation process, a solid electrolyte interface (SEI) is deposited on the anode. The SEI (not shown) is formed by the reduction of electrolyte solvents, additives, and salts. The reduction of the electrolyte occurs at a characteristic voltage and is accompanied by the generation of gases that must be vented from the cavity. To this end, as Figure 1 and Figure 2As shown in FIG, the battery cell 20 further includes a gas pocket 26 in fluid communication with the cavity. The gas pocket 26 is configured to expand from a deflated configuration to an inflated configuration when filled with gas formed during the cell forming process of the battery cell 20.

[0034] Current practices for analyzing the quality of battery cells 20 involve performing discharge capacity checks (i.e., checking that the battery provides capacity (measured in ampere-hours) within established specifications) or performing inventory maintenance and open circuit voltage (OCV) monitoring (which involves maintaining inventory and checking for OCV reduction over time). While effective, such quality control measures are time-intensive (with the potential for significant quality overflow and the additional overhead cost of storing inventory) and the data is poor (i.e., not diagnostic or predictive).

[0035] Data can be obtained from formation, end-of-life capacity checks, and cell manufacturing tracking as a means of performing efficient production line quality checks. For example, data related to the formation charge of the battery cell 20 and the discharge check of the battery cell can be utilized. More specifically, pattern recognition from formation cycle data is combined with discharge checks in accelerated cycle testing (ACT) to generate learning feedback. ACT is a short-term aging and cycling test used to determine whether candidate cells from a specific batch of battery cells meet durability requirements based on 100 to 300 charge and discharge cycles and is delayed by not incorporating quality control (QC) checks during the time-consuming formation protocol. Feedback identified during the cell formation cycle has been identified to provide more timely corrective actions during cell manufacturing. Performing explicit quality checks early in the manufacturing process reduces the need for voltage drop testing of the battery cell and cell pack storage. Data-rich process monitoring improves cell quality and is cost-effective when performed during the rate-limiting step of assembly. Data processing using advanced analytics is used to generate and monitor key features of electrochemical signatures. Examples of analyzing data related to forming charge and discharge checks of battery cells 20 are shown and described in concurrently filed U.S. patent application Ser. No. 17 / 350,620, entitled “ELECTROCHEMICAL METHODS FOR IDENTIFICATION OF CELL QUALITY,” filed on June 17, 2021, the disclosure of which is incorporated herein by reference.

[0036] Gases generated by the (battery) cell formation process can also provide data that can be used to assess the quality of the battery cell 20. Excessive gas production may indicate a low-quality battery cell 20. More specifically, in one example, the battery cell 20 is expected to produce between 0.5 mL and 3 mL of gas per Ah of nominal capacity. If the amount of gas produced is greater than 3 mL / Ah of nominal capacity or less than 0.5 mL / Ah of nominal capacity, the battery cell 20 may be of low quality. Excessive gas can be due to several reasons. As an example, complete deactivation of electrolyte additives such as ethylene carbonate (VC), ethylene ethylene carbonate (VEC), etc. will lead to excessive consumption of ethylene carbonate (EC), thereby generating gas. In this case, these battery cells 20 exhibit very poor charge retention during cycling. Poor additive performance due to partial failure and degradation can also lead to excessive EC consumption and increased gas generation, although not to the extent seen in the above example.

[0037] Typically, a small gas volume results in the highest initial charge capacity of the battery cell 20, while an increase in gas volume (due to EC reduction) is associated with a degradation of the charge capacity over time. Excessive reduction of ethylene carbonate (EC) during the formation cycle consumes lithium salts in the electrolyte, which reduces the total available "lithium inventory" in the battery cell 20, which reduces the ultimate charge capacity. Poor electrolyte additive performance causes the SEI layer to decompose more quickly. Therefore, additional EC reduction is necessary to maintain the SEI layer. The SEI layer formed primarily by EC reduction has poor mechanical properties and a greater thickness, which is inferior to the SEI layer formed in the presence of the electrolyte additive.

[0038] An example of measuring and analyzing data related to the volume of gas generated during the formation of a battery cell 20 is shown and described in U.S. patent application Ser. No. 17 / 350,644, filed concurrently on June 17, 2021, entitled “QUALITY CONTROL SYSTEM FOR ANALYZING THE QUALITY OF A BATTERY CELL THROUGH AVOLUMETRICMEASUREMENT OF GAS FORMED DURING A CELL FORMATION PROCESS AND A METHOD OF ANALYZING THE SAME,” the disclosure of which is incorporated herein by reference.

[0039] Furthermore, the composition of the gas provides data that can be used to assess the quality of the battery cell 20. For example, certain substances are consistently found in the gas pocket 26 after the cell formation process. These substances include methane, ethylene, ethane, butane and its isomers, hydrogen, carbon monoxide, and carbon dioxide. The individual composition of these substances may indicate quality defects during the cell formation process, such as the absence of additives, moisture, aged electrolyte, and lean electrolyte. Furthermore, the accumulated amount of a substance may be greater than a threshold value and indicate a low-quality battery cell 20. An example of measuring and analyzing data related to the composition of gases generated during the formation of a battery cell 20 is shown and described in U.S. patent application Ser. No. 17 / 350,650, filed concurrently on June 17, 2021, entitled “QUALITY CONTROL SYSTEM FOR ANALYZING THE QUALITY OFA BATTERY CELL THROUGH ANALYSIS OF A PHYSICAL PROPERTY OF A GAS FORMED DURINGA CELL FORMATION PROCESS AND A METHOD OF ANALYZING THE SAME,” the disclosure of which is incorporated herein by reference.

[0040] According to several aspects of the present disclosure, this document discloses and Figure 3 2 shows a method 200 for analyzing the quality of a battery cell 20. The method includes performing a high-throughput quality inspection on the battery cell 20 using a quality control system, as shown in block 202, and evaluating a quality score for the battery cell 20, as shown in block 204, wherein the quality score identifies the battery cell 20 as low quality or high quality. If the battery cell 20 is identified as high quality, the method further includes reintroducing the battery cell 20 into production, as shown in block 206. The method further includes performing a comprehensive quality inspection on the battery cell 20, as shown in block 208, if identified as low quality. The method further includes evaluating an enhanced quality score for the battery cell 20, replacing the quality score of the quality control system, identifying the battery cell 20 as confirmed low quality or confirmed high quality, as shown in block 210, and providing modified production instructions for manufacturing subsequent battery cells 20, as shown in block 212, if confirmed as low quality.

[0041] High-throughput quality inspection of battery cells 20 with a quality control system provides a way to perform efficient line quality inspection. More specifically, performing high-throughput quality inspection of battery cells 20 with a quality control system, as shown in block 202, can also be defined as analyzing cell charge data of the battery cells 20, analyzing the volume of gas within the gas pockets 26 of the battery cells 20, analyzing the composition of the gas within the gas pockets 26, and analyzing discharge inspection data of the battery cells 20, all of which have been described above and incorporated herein by reference. As mentioned above, current methods of inspecting the quality of battery cells 20 require maintaining inventory for lot acceptance testing (LAT), which involves maintaining inventory and inspecting the reduction in OCV over time. Current OCV inspections require a maximum of seven days of maintenance. Therefore, the term "high-throughput" can mean less than seven days. However, typically, the amount of time is less than this, with most of the processes mentioned above being performed within minutes, or (in some cases) within seconds.

[0042] The terms "high quality" and "low quality" refer, in part, to the ability of the battery cell 20 to hold a charge. As described above, the battery's ability to hold a charge is at least partially related to the cell formation process and, in addition, to whether the SEI is properly formed on the electrodes. The above-described processes, in their respective applications, provide a means of collecting data that analyzes whether the battery cell 20 can hold a charge, whether the SEI is properly formed, or both. This data is analyzed against thresholds to derive a quality indicator.

[0043] The method may utilize a computing system. The computing system may include at least one processor and a memory containing program instructions. Memory may also be defined as non-transitory computer-readable media, including but not limited to random access memory (RAM), hard drives, and flash drives. The computing system may be used to perform each of the steps of the method described herein. For example, the processor may perform a high-throughput quality check based on instructions from the memory. Data collected from the high-throughput quality check may also be analyzed by the processor and compared with information stored in the memory (such as thresholds). The processor may assess a quality score based on the analysis. As another example, the processor may perform a comprehensive quality check on the battery cells based on instructions from the memory. Data collected from the comprehensive quality check may also be analyzed by the processor and compared with information stored in the memory (such as thresholds). The processor may assess an enhanced quality score based on the analysis. The processor may also provide modified production instructions for manufacturing successive battery cells. It should be understood that the computing system may be used in any step of the method, such that some or all of the method is automated.

[0044] The quality control system may also be defined as a first quality control system, and the quality score may also be defined as the first quality score. The method may further include performing a high-throughput quality inspection on the battery cell 20 using a second quality control system, as shown in block 214. The second quality control system may be further defined as analyzing one of cell charge data of the battery cell 20, analyzing the volume of gas within the gas pocket 26 of the battery cell 20, analyzing the composition of the gas within the gas pocket 26, and analyzing discharge inspection data of the battery cell 20 not performed by the first quality control system, and evaluating a second quality score of the battery cell 20, as shown in block 216, the second quality score identifying the battery cell 20 as low quality or high quality. The method may further include analyzing the first quality score and the second quality score, and evaluating a global quality score identifying the battery cell 20 as low quality or high quality, as shown in block 218. Evaluating the global quality score occurs before performing a full quality inspection on the battery cell 20. The global quality score is an average of the quality scores of the first quality control system and the second quality control system. Accordingly, the second quality control system may adjust the position of the quality score of the first quality control system (i.e., increase or decrease the quality score). This scales the two quality scores and provides a clearer assessment of the quality of the battery cell 20 .

[0045] In one example, performing high-throughput quality inspection on the battery cells 20 using a first quality control system as shown in block 202 is further defined as analyzing the cell formation charge data of the battery cells 20, and performing high-throughput quality inspection on the battery cells 20 using a second quality control system as shown in block 214 is further defined as analyzing the composition of the gas within the gas bag 26, wherein analyzing the cell formation charge data of the battery cells 20 occurs before analyzing the composition of the gas within the gas bag 26. Electrochemical signals can indicate which gases are being generated and the amount of gas being generated. Furthermore, gas analysis can be used to confirm these results and search for additional information regarding the root cause of the defect.

[0046] In another example, performing high-throughput quality inspection on the battery cells 20 using a first quality control system as shown in block 202 is further defined as analyzing cell-formed charge data of the battery cells 20, and performing high-throughput quality inspection on the battery cells 20 using a second quality control system as shown in block 214 is further defined as analyzing the gas volume within the gas pockets 26 of the battery cells 20, wherein analyzing the cell-formed charge data of the battery cells 20 occurs before analyzing the gas volume within the gas pockets 26 of the battery cells 20. Electrochemical characteristics can indicate the amount of gas generated. Gas volume estimation methods can be used for validation and to assist in root cause analysis.

[0047] In another example, performing a high-throughput quality check on the battery cells 20 with the first quality control system as shown in block 202 is further defined as analyzing cell formation charge data of the battery cells 20, and wherein performing a high-throughput quality check on the battery cells 20 with the second quality control system as shown in block 214 is further defined as analyzing battery cell 20 discharge check data, wherein analyzing the cell formation charge data of the battery cells 20 occurs before analyzing the battery cell 20 discharge check data. Analysis of the beginning-of-life capacity check discharge curve can be used as another check of cell quality and to identify formation conditions that may lead to better long-term cell performance.

[0048] In one example, if low quality is identified as shown in block 208, performing a comprehensive quality check on the battery cell 20 is further defined as performing a gas chromatography analysis of the gas within the gas bag 26. In another example, if low quality is identified as shown in block 208, performing a comprehensive quality check on the battery cell 20 is further defined as performing an ACT (Acceptance Control) through aging and repeated charge and discharge cycles. Furthermore, both performing a gas chromatography analysis on the gas within the gas bag 26 and performing an ACT (Acceptance Control) through aging and repeated charge and discharge cycles can occur on the battery cell 20. To perform the gas chromatography analysis, the gas within the gas bag 26 is removed from the gas bag 26 and passed through a gas chromatograph. Gas chromatography is a process that separates compounds within the gas within the gas bag 26, allowing for a thorough analysis of the gas's composition. The composition of the gas within the low-quality battery cell 20 can be compared to known compositions found in healthy battery cells 20. Deviations in composition can be used to determine the root cause of the low-quality battery cell 20 (e.g., absence of additives, poor electrolyte, aged electrolyte, humidity, etc.). While gas chromatography provides a more thorough analysis of battery cells 20, gas chromatographs are typically expensive to own and operate, and require significantly longer time to analyze the gas than the time required by the aforementioned quality control system. Furthermore, the long cycles performed during the ACT provide a more accurate assessment of the battery cell's 20 ability to hold a charge. However, as described above, the ACT can take up to five months to perform. Therefore, the aforementioned quality control system provides an accurate way to screen the quality of battery cells 20, performing a thorough analysis of battery cells 20 deemed to be of low quality through comprehensive quality checks performed by gas chromatography, LAT, and the like.

[0049] In one example, as shown in block 212, if low quality is confirmed, providing modified production instructions for manufacturing subsequent battery cells 20 is further limited to providing instructions for adaptive formation charge parameters. Adapting formation charge parameters refers to performing corrective actions on the cell formation process. More specifically, data from the cell formation process (such as voltage, current, pressure, and temperature versus time) is monitored in real time, and (if necessary) corrective measures on the formation schedule can be implemented based on feedback from the full quality inspection to ensure desired SEI formation. Corrective actions can include a processor of the computing system (or another computing system within the network) instructing a power supply to apply a corrective constant current or maintain a corrective first and / or second voltage limit to subsequent battery cells 20 during the cell formation process. The computing system can also instruct a temperature control module to correct the ambient temperature of subsequent battery cells 20 during the cell formation process (e.g., using a heater and / or air conditioner). Data from the battery formation process, along with analysis results from the full quality inspection and corrective actions on the cell formation process, can be archived in a network repository. Information from this repository can be used to further analyze the quality of (battery) cells on the production line.

[0050] Based on metadata analysis using the above-described data streams, the method allows for distinguishing (with high certainty) the difference between the best performing unacceptable (low quality) battery cells 20 and the lowest performing acceptable (high quality) battery cells 20. The battery cells 20 can include a traceable identifier (such as a barcode) from which information from the quality data can be accessed. Based on the combined scores of these data streams, the (battery) cells can be binned according to performance (e.g., high, medium, and low) or rejected as defective. The metadata and raw data from the rejected cells can be subjected to upgraded analysis to determine the root cause of the defect. In addition, tracking of raw material batches and other process monitoring can be used to identify other battery cells 20 in the defective (battery) cell group (which may also have this defect) for isolation and possible remedial processing to correct the error.

[0051] The method 200 may also include reintroducing the battery cell 20 into production if the battery cell 20 is confirmed to be of high quality, as shown in box 220. More specifically, if the battery cell 20 is found to have a quality that falls within the desired specifications, the battery cell 20 can be put back into production as part of a battery pack or in any other configuration and sold individually. On the other hand, the method 200 may also include scrapping the battery cell 20 if the battery cell 20 is confirmed to be of low quality, as shown in box 222 (i.e., permanently removing the battery cell 20 from production). The battery cell 20 can be disassembled and the components can be used for recycling. In addition, the battery cell 20 can be reused in other non-vehicle applications, such as stationary power applications.

[0052] Thus, the method 200 for analyzing the quality of battery cells 20 provides several advantages. Checking the quality of battery cells 20 during and / or after the cell formation process reduces the need for the long inventory holding and OCV monitoring currently practiced, which increases manufacturing throughput. Furthermore, comprehensive quality inspection of battery cells 20 previously identified as low quality allows for more efficient root cause analysis.

[0053] The description of the present disclosure is merely exemplary in nature, and variations that do not depart from the gist of the present disclosure are intended to fall within the scope of the present disclosure. Such variations should not be regarded as a departure from the spirit and scope of the present disclosure.

Claims

1. A method for analyzing the quality of a battery cell, the method comprising: performing a first high-throughput quality inspection on the battery cell using a first quality control system, wherein the first high-throughput quality inspection is further defined as one of analyzing cell charge data of the battery cell, analyzing a volume of gas within an air pocket of the battery cell, analyzing a composition of the gas within the air pocket, and analyzing discharge inspection data of the battery cell; evaluating a first quality score of the battery cell and identifying the battery cell as low quality or high quality; performing a second high-throughput quality inspection on the battery cell using a second quality control system, wherein the second quality control system is further defined as one of analyzing the cell-formed charge data of the battery cell, analyzing the volume of the gas within the gas pocket of the battery cell, analyzing the composition of the gas within the gas pocket, and analyzing the battery cell discharge inspection data not performed by the first quality control system, and wherein the second quality control system is different from the first quality control system; and evaluating a second quality score for the battery cell, wherein the second quality score identifies the battery cell as being of low quality or high quality; averaging the first quality score and the second quality score to generate a global quality score, wherein the global quality score identifies the battery cell as low quality or high quality; When the battery cell is identified as low quality by the global quality score, performing a comprehensive quality inspection on the battery cell, wherein the comprehensive quality inspection includes performing a gas chromatography analysis on a gas within an air pocket of the battery cell identified as low quality and performing an accelerated cycle test (ACT) by aging and repeating charge and discharge cycles on the battery cell identified as low quality; evaluating an enhanced quality score for the battery cell based on the comprehensive quality inspection, wherein the enhanced quality score identifies the battery cell as low quality or high quality, wherein the enhanced quality score replaces the global quality score; and providing modified production instructions for manufacturing subsequent battery cells when the enhanced quality score identifies the battery cell as low quality, and wherein the modified production instructions are instructions for adaptively forming charging parameters to perform corrective actions on the formation process of the battery cell based on feedback from the comprehensive quality inspection, the corrective actions comprising instructing a power supply to apply a corrective constant current or maintain a corrective voltage limit for subsequent battery cells during the battery cell formation process; When the battery cell is identified as being of high quality, the battery cell is reintroduced into production.

2. The method of claim 1 , wherein performing the first high-throughput quality inspection on the battery cells with a first quality control system is further defined as analyzing the cell-formed charge data of the battery cells, and wherein performing the second high-throughput quality inspection on the battery cells with the second quality control system is further defined as analyzing the composition of the gas within the gas bag, wherein analyzing the cell-formed charge data of the battery cells occurs before analyzing the composition of the gas within the gas bag.

3. The method of claim 1 , wherein performing the first high-throughput quality inspection on the battery cell with a first quality control system is further defined as analyzing the cell-formed charge data of the battery cell, and wherein performing the second high-throughput quality inspection on the battery cell with the second quality control system is further defined as analyzing the gas volume within the gas pocket of the battery cell, wherein analyzing the cell-formed charge data of the battery cell occurs before analyzing the gas volume within the gas pocket of the battery cell.

4. The method of claim 1 , wherein performing the first high-throughput quality inspection on the battery cells with a first quality control system is further defined as analyzing the cell-formed charge data of the battery cells, and wherein performing the second high-throughput quality inspection on the battery cells with the second quality control system is further defined as analyzing the battery cell discharge inspection data, wherein analyzing the cell-formed charge data of the battery cells occurs before analyzing the battery cell discharge inspection data.

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