Battery cell activation system and method

Abstract

The present invention provides a battery cell activation system comprising: a pre-charging unit (100) for pre-charging a battery cell which may be in a pre-impregnation state in which the battery cell has yet to be sufficiently impregnated with an electrolyte injected therein; a profile acquisition unit (200) for acquiring a voltage or capacity profile of the battery cell on the basis of information measured while the battery cell is being pre-charged by the pre-charging unit (100); and a quality determination unit (300) for predicting or determining the quality of the battery cell on the basis of the profile.

Description

Battery cell activation system and method

[0001] This application claims the benefit of priority from Republic of Korea Patent Application No. 10-2024-0086371, dated July 1, 2024, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a battery cell activation system and method, and more particularly, to a battery cell activation system and method that improves the efficiency of the activation process, prevents waste of time and cost, correctly determines the cause of a battery cell defect, and accurately, easily, and effectively predicts or determines whether a battery cell is good or bad.

[0003] Secondary batteries (hereinafter referred to as battery cells), which can be repeatedly charged and discharged, are attracting attention as an alternative to fossil fuels. Currently, battery cells are widely used in various fields, including electric vehicles (EVs, HEVs, PHEVs), energy storage systems (ESS), and uninterruptible power supply systems (UPS).

[0004] During battery cell manufacturing, an activation process is performed on the assembled battery cells, including a series of processes such as pre-charge, pre-aging, primary charging, aging, and defect detection.

[0005] Precharge is a process of pre-charging a battery cell before the electrolyte has fully impregnated the electrodes (before impregnation is complete). Precharge lowers the potential of the battery cell's negative electrode, preventing foreign substances or metals such as copper from being released from the electrodes during electrolyte impregnation. This prevents low-voltage defects (self-discharge abnormalities) in the battery cell.

[0006] The pre-aging process is a process of leaving the battery cell to be sufficiently impregnated (impregnation complete) with the electrolyte of the battery cell into the electrode assembly.

[0007] The first charging process is a charging process that forms a SEI (Solid Electrolyte Interface) film on the negative electrode surface of the battery cell.

[0008] The aging process is a process of leaving the battery cell to stabilize the SEI film formed on the electrode surface of the battery cell.

[0009] The defect detection process is a process for detecting impregnation defects or low voltage defects in battery cells.

[0010] Since defect detection of battery cells is performed at the end of the activation process, the problem arises of lengthy processes such as pre-aging, primary charging, and aging being performed on battery cells that are predicted to be defective or already defective from the beginning of the activation process. This wastes time and money, and reduces the efficiency of the activation process.

[0011] Therefore, a method is required to detect defective or predicted defective battery cells early in the activation process.

[0012] Prior art literature related to this is Korean Patent Publication No. 10-2023-0037942.

[0013] The present invention has been devised to solve the above-described problems, and aims to provide a battery cell activation system and method that improves the efficiency of the activation process by preventing time and cost from being wasted due to performing a long-time activation process (aging and / or charge / discharge) on a battery cell that is predicted to be defective or is defective.

[0014] In addition, the purpose is to provide a battery cell activation system and method that reduces the manufacturing cost of battery cells, improves production efficiency, and lowers the defect rate.

[0015] In addition, the purpose is to provide a battery cell activation system and method in which the essential cause of a defect in a battery cell is correctly determined.

[0016] In addition, the purpose is to provide a battery cell activation system and method that accurately, easily, and effectively predicts or determines the quality of a battery cell.

[0017] The technical objectives of the present invention are not limited to the purposes mentioned above. Other objectives and advantages of the present invention not mentioned above can be understood through the following description and will be more clearly understood through the embodiments of the present invention. Furthermore, it will be readily apparent that the objectives and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims.

[0018] In order to solve the above-described problem, the present invention provides a battery cell activation system (10) including a pre-charge unit (100), a profile acquisition unit (200), and a pass / fail determination unit (300).

[0019] The above-mentioned pre-charge unit (100) can pre-charge a battery cell that may be in a pre-impregnation state, that is, a state before the electrolyte injected inside is sufficiently impregnated.

[0020] The above profile acquisition unit (200) can acquire a profile regarding the voltage or capacity of the battery cell based on information measured while the battery cell is being precharged by the precharge unit (100).

[0021] The above-mentioned quality determination unit (300) can predict or determine the quality of the battery cell based on the above-mentioned profile.

[0022] In one embodiment, the precharge unit (100) can precharge the battery cell, which may be in a pre-aging state.

[0023] In one embodiment, the profile may include a voltage profile relating to the voltage of the battery cell over time.

[0024] In one embodiment, the precharge unit (100) can precharge the battery cell to a cutoff voltage.

[0025] The above-mentioned positive / negative judgment unit (300) can calculate the cutoff voltage or the cutoff time (F) to reach the highest voltage based on the voltage profile.

[0026] The above-mentioned good / bad judgment unit (300) can predict or judge the good / bad of the battery cell based on the cut-off time (F).

[0027] In one embodiment, the positive / negative judgment unit (300) can calculate the voltage change rate at the beginning of the precharge based on the voltage profile.

[0028] The above-mentioned good / bad judgment unit (300) can predict or judge the good / bad of the battery cell based on the voltage change rate.

[0029] In one embodiment, the positive / negative judgment unit (300) can calculate a discrimination time (T) based on the voltage profile to distinguish between an initial section (IS), which is a time section at the beginning of the precharge, and a gradual section (GS), which is a time section after the initial section (IS), is adjacent to the initial section (IS), and has a voltage change rate (dV / dT) that is smaller than the voltage change rate in the initial section (IS), or calculate a slope of the gradual section (GS).

[0030] The above-mentioned good / bad judgment unit (300) can predict or judge the good / bad of the battery cell based on the discrimination time (T) or the slope of the smooth section (GS).

[0031] In one embodiment, the profile may include a differential profile relating to a voltage-capacity profile (dQ / dV or dV / dQ) relating to voltage and capacity of the battery cell.

[0032] In one embodiment, the positive / negative judgment unit (300) can determine whether a main peak (P) or a main bottom exists based on the differential profile, or, if the main peak (P) or the main bottom exists, calculate the differential value corresponding to the main peak (P) or the main bottom.

[0033] The above-mentioned good / bad judgment unit (300) can predict or determine the good / bad of the battery cell based on the presence or absence of the main peak (P) or main bottom or the differential value corresponding to the main peak (P) or main bottom.

[0034] In one embodiment, the good / bad judgment unit (300) can predict or determine that the battery cell is defective if the differential value (dQ / dV) corresponding to the main peak (P) is greater than an upper limit (U, the upper limit is a positive real number) or less than a lower limit (L, the lower limit is a positive real number less than the upper limit), or if the differential value (dV / dQ) corresponding to the main bottom is greater than a multiplicative inverse of the lower limit (L) or less than a multiplicative inverse of the upper limit (U).

[0035] In one embodiment, the upper limit (U) may be greater than or equal to 0.04 mAh / mV and less than or equal to 0.06 mAh / mV, or the lower limit (L) may be greater than or equal to 0.01 mAh / mV and less than or equal to 0.03 mAh / mV.

[0036] In one embodiment, the pre-charge unit (100) can pre-charge the reference battery cell, which is the battery cell in the pre-impregnation state, and the measurement battery cell, which is the battery cell that can be in the pre-impregnation state.

[0037] The above profile acquisition unit (200) can acquire the reference profile and the measurement profile, which are the profiles for each of the reference battery cell and the measurement battery cell.

[0038] The above-mentioned good / bad judgment unit (300) can predict or judge the good / bad of the measured battery cell based on the reference profile and the measurement profile.

[0039] In one embodiment, the precharge unit (100) may precharge the reference battery cell and the measurement battery cell in the same or similar manner, or the environment in which the reference battery cell and the measurement battery cell are placed may be the same or similar from the time the electrolyte is injected into the reference battery cell and the measurement battery cell until the precharge is completed by the precharge unit (100).

[0040] In one embodiment, the reference profile may include a first voltage profile relating to the voltage of the reference battery cell over time.

[0041] The above measurement profile may include a second voltage profile relating to the voltage of the measured battery cell over time.

[0042] In one embodiment, the precharge unit (100) can precharge the reference battery cell and the measurement battery cell to a cutoff voltage.

[0043] The above-mentioned positive / negative judgment unit (300) can calculate the first cut-off time (F1) for reaching the cut-off voltage or the highest voltage based on the first voltage profile.

[0044] The above-mentioned good / bad judgment unit (300) can calculate the second cut-off time (F2) for reaching the cut-off voltage or the highest voltage based on the second voltage profile. The above-mentioned good / bad judgment unit (300) can predict or determine the measured battery cell as defective if the value obtained by subtracting the second cut-off time (F2) from the first cut-off time (F1) is greater than a first threshold value (the first threshold value is a positive real number).

[0045] In one embodiment, the positive / negative judgment unit (300) can calculate the first voltage change rate, which is the voltage change rate (dV / dT) at the beginning of the precharge, based on the first voltage profile.

[0046] The above-mentioned positive / negative judgment unit (300) can calculate the second voltage change rate (dV / dT), which is the voltage change rate at the beginning of the precharge, based on the second voltage profile.

[0047] The above-mentioned good / bad judgment unit (300) can predict or determine that the measured battery cell is defective if the value obtained by subtracting the first voltage change rate from the second voltage change rate is greater than the second threshold value (the second threshold value is a positive real number).

[0048] In one embodiment, the positive / negative judgment unit (300) can calculate a first distinction time (T1) based on the first voltage profile to distinguish between a first initial period (IS1), which is a time period at the beginning of the precharge, and a first slow period (GS1), which is a time period after the first initial period (IS1), is adjacent to the first initial period (IS1), and has a voltage change rate (dV / dT) that is smaller than the voltage change rate in the first initial period (IS1).

[0049] The above-mentioned positive / negative judgment unit (300) can calculate a second distinction time (T2) based on the second voltage profile to distinguish between a second initial period (IS2), which is a time period at the beginning of the pre-charge, and a second slow period (GS2), which is a time period after the second initial period (IS2), is adjacent to the second initial period (IS2), and has a voltage change rate smaller than the voltage change rate in the second initial period (IS2).

[0050] The above-mentioned good / bad judgment unit (300) can predict or determine that the measured battery cell is defective if the value obtained by subtracting the second discrimination time (T2) from the first discrimination time (T1) is greater than the third threshold value (the third threshold value is a positive real number).

[0051] In one embodiment, the reference profile may include a first differential profile relating to a differential value (dQ / dV or dV / dQ) of a voltage-capacity profile relating to voltage and capacity of the reference battery cell.

[0052] The above measurement profile may include a second differential profile relating to a differential value (dQ / dV or dV / dQ) of a voltage-capacity profile relating to voltage and capacity of the measured battery cell.

[0053] In one embodiment, the positive / negative judgment unit (300) can calculate the differential value corresponding to the first peak (P1), which is the main peak (P), or the first bottom, which is the main bottom, based on the first differential profile.

[0054] The above-mentioned positive / negative judgment unit (300) can calculate a differential value corresponding to the second peak (P2) corresponding to the first peak (P1) and being the main peak (P) or the second bottom corresponding to the first bottom and being the main bottom based on the second differential profile.

[0055] The above-mentioned good / bad judgment unit (300) can predict or determine the measured battery cell as defective if the value obtained by subtracting the differential value (dQ / dV) corresponding to the first peak (P1) from the differential value (dQ / dV) corresponding to the second peak (P2) is greater than a fourth threshold value (the fourth threshold value is a positive real number) or if the value obtained by subtracting the differential value (dV / dQ) corresponding to the second bottom from the differential value (dV / dQ) corresponding to the first bottom is greater than a fifth threshold value (the fifth threshold value is a positive real number).

[0056] In one embodiment, the positive / negative judgment unit (300) can obtain a first peak (P1), which is a main peak (P), or a first bottom, which is a main bottom, based on the first differential profile.

[0057] The above-mentioned positive / negative judgment unit (300) can determine the presence or absence of a second peak (P2) corresponding to the first peak (P1) and being a main peak (P) or a second bottom corresponding to the first bottom and being a main bottom based on the second differential profile, or can calculate the differential value corresponding to the second peak (P2) or the second bottom when the second peak (P2) or the second bottom exists.

[0058] The above-mentioned good / bad judgment unit (300) can predict or determine the measured battery cell as defective if the second peak (P2) or the second bottom does not exist, or if the value obtained by subtracting the differential value (dQ / dV) corresponding to the second peak (P2) from the differential value (dQ / dV) corresponding to the first peak (P1) is greater than a sixth threshold value (the sixth threshold value is a positive real number), or if the value obtained by subtracting the differential value (dV / dQ) corresponding to the first bottom from the differential value (dV / dQ) corresponding to the second bottom is greater than a seventh threshold value (the seventh threshold value is a positive real number).

[0059] In addition, in order to solve the above-described problem, the present invention provides a battery cell activation method (S900) including a pre-charging process (S910), a profile acquisition process (S920), a pass / fail determination process (S930), an aging process (S940), and a first charging process (S950).

[0060] In the above pre-charging process (S910), the pre-charging unit (100) can pre-charge the battery cell, which may be in a pre-impregnation state before the electrolyte injected inside is sufficiently impregnated.

[0061] In the above profile acquisition process (S920), the profile acquisition unit (200) can acquire the profile regarding the voltage or capacity of the battery cell based on information measured while the battery cell is being precharged by the precharge unit (100).

[0062] In the above-mentioned good / bad judgment process (S930), the good / bad judgment unit (300) can predict or determine the good / bad of the battery cell based on the profile.

[0063] In the above aging process (S940), the battery cell determined to be good in the above quality determination process (S930) can be aged.

[0064] In the first charging process (S950), the charging / discharging unit (400) can charge the battery cell determined to be good in the good / bad judgment process (S930).

[0065] According to embodiments of the present invention, a battery cell activation system (10) may include a pre-charge unit (100) that pre-charges a battery cell, which may be in a pre-impregnation state before the electrolyte injected therein is sufficiently impregnated; a profile acquisition unit (200) that acquires a profile regarding voltage or capacity of the battery cell based on information measured while the battery cell is being pre-charged by the pre-charge unit (100); and a pass / fail determination unit (300) that predicts or determines pass / fail of the battery cell based on the profile.

[0066] Accordingly, defective or likely defective battery cells can be detected early in the activation process (after pre-charging) before the aging process, which involves long-term maturation of the battery cells to ensure sufficient electrolyte impregnation within the electrode assembly. This prevents the waste of time and money associated with the lengthy activation process (aging and / or charge / discharge) on defective or likely defective battery cells. Consequently, the efficiency of the activation process can be improved, the manufacturing cost of battery cells can be reduced, production efficiency can be enhanced, and the defect rate can be reduced.

[0067] In addition, the cause of a battery cell defect can be correctly determined. For example, a battery cell that is phenomenologically a low-voltage defect but essentially an impregnation defect (e.g., due to insufficient electrolyte injection amount) can be correctly predicted or determined as an impregnation defect (e.g., due to insufficient electrolyte injection amount) rather than a low-voltage defect, unlike in the past. This is because a low-voltage defect is determined after the shipping charge or shipping discharge at the end of the activation process, but an impregnation defect (e.g., due to insufficient electrolyte injection amount) can be predicted or determined by the pass / fail determination unit (300) before a low-voltage defect at the beginning of the activation process. Accordingly, the essential cause of a battery cell defect can be correctly determined.

[0068] According to embodiments of the present invention, the precharge unit (100) can precharge the battery cell, which may be in a state before aging.

[0069] Accordingly, defective or predicted battery cells can be detected early in the activation process before aging. This prevents the waste of time and money due to lengthy activation processes (aging and / or charging / discharging) performed on predicted or predicted defective battery cells.

[0070] According to embodiments of the present invention, the profile may include a voltage profile regarding the voltage of the battery cell over time.

[0071] Accordingly, the quality or failure of battery cells can be accurately and effectively predicted or determined. This is because the voltage profiles of good and defective battery cells differ.

[0072] According to embodiments of the present invention, the precharge unit (100) can precharge the battery cell to a cutoff voltage. The quality determination unit (300) can calculate a cutoff time (F) for reaching the cutoff voltage or the highest voltage based on the voltage profile, and can predict or determine the quality of the battery cell based on the cutoff time (F).

[0073] Accordingly, the quality of battery cells can be accurately, easily, and effectively determined. This is because the times required for good and defective battery cells to reach the cutoff voltage (or peak voltage) differ.

[0074] According to embodiments of the present invention, the quality judgment unit (300) can calculate the voltage change rate at the beginning of the precharge based on the voltage profile, and predict or determine the quality of the battery cell based on the voltage change rate.

[0075] Accordingly, the quality of battery cells can be accurately, easily, and effectively determined. This is because the voltage change rates at the initial precharge stage of good and defective battery cells differ.

[0076] According to embodiments of the present invention, the quality judgment unit (300) calculates a distinction time (T) for distinguishing between an initial section (IS), which is a time section at the beginning of the precharge, based on the voltage profile, and a smooth section (GS), which is a time section after the initial section (IS), is adjacent to the initial section (IS), and has a voltage change rate (dV / dT) smaller than the voltage change rate in the initial section (IS), or calculates a slope of the smooth section (GS), and can predict or determine the quality of the battery cell based on the distinction time (T) or the slope of the smooth section (GS).

[0077] Accordingly, the quality of a battery cell can be accurately, easily, and effectively determined. This is because the time it takes for a good battery cell to transition from the initial section (IS) to the gradual section (GS) in the voltage profiles of a good battery cell to the gradual section (GS) differs, and the slope (dV / dT) of the gradual section (GS) differs.

[0078] According to embodiments of the present invention, the profile may include a differential profile regarding a differential value (dQ / dV or dV / dQ) obtained by differentiating a voltage-capacity profile regarding voltage and capacity of the battery cell.

[0079] Accordingly, the quality of battery cells can be accurately and effectively predicted or determined. This is because the differential profiles of good and defective battery cells differ.

[0080] According to embodiments of the present invention, the good / bad judgment unit (300) determines whether a main peak (P) or a main bottom exists based on the differential profile, or if the main peak (P) or the main bottom exists, calculates the differential value corresponding to the main peak (P) or the main bottom, and can predict or determine whether the battery cell is good / bad based on the presence of the main peak (P) or the main bottom or the differential value corresponding to the main peak (P) or the main bottom.

[0081] Accordingly, the quality of a battery cell can be accurately, easily, and effectively determined. This is because, unlike the differential profile of a good battery cell, the differential profile of a defective battery cell does not have a major peak (P) or major bottom, or the differential values ​​corresponding to the major peak (P) or major bottom in the differential profiles of a good battery cell and a defective battery cell are different.

[0082] According to embodiments of the present invention, the good / bad judgment unit (300) can predict or determine that the battery cell is defective if the differential value (dQ / dV) corresponding to the main peak (P) is greater than an upper limit (U, the upper limit is a positive real number) or less than a lower limit (L, the lower limit is a positive real number smaller than the upper limit), or if the differential value (dV / dQ) corresponding to the main bottom is greater than a multiplicative inverse of the lower limit (L) or less than a multiplicative inverse of the upper limit (U).

[0083] Accordingly, the quality of the battery cell can be accurately, easily and effectively determined.

[0084] According to embodiments of the present invention, the upper limit (U) may be 0.04 mAh / mV or more and 0.06 mAh / mV or less, or the lower limit (L) may be 0.01 mAh / mV or more and 0.03 mAh / mV or less.

[0085] Accordingly, the quality of the battery cell can be accurately determined.

[0086] According to embodiments of the present invention, the pre-charge unit (100) can pre-charge the reference battery cell, which is the battery cell in the pre-impregnation state, and the measurement battery cell, which is the battery cell that may be in the pre-impregnation state. The profile acquisition unit (200) can acquire the reference profile and the measurement profile, which are the profiles for the reference battery cell and the measurement battery cell, respectively. The pass / fail determination unit (300) can predict or determine the pass / fail of the measurement battery cell based on the reference profile and the measurement profile.

[0087] Accordingly, the quality of the measured battery cell can be accurately and easily predicted or determined by comparing it with the reference battery cell.

[0088] According to embodiments of the present invention, the precharge unit (100) may precharge the reference battery cell and the measurement battery cell in the same or similar manner, or the environment in which the reference battery cell and the measurement battery cell are placed may be the same or similar from the time the electrolyte is injected into the reference battery cell and the measurement battery cell until the precharge is completed by the precharge unit (100).

[0089] Accordingly, the quality of the measured battery cell can be accurately predicted or determined in comparison with the reference battery cell.

[0090] According to embodiments of the present invention, the reference profile may include a first voltage profile relating to the voltage of the reference battery cell over time. The measurement profile may include a second voltage profile relating to the voltage of the measurement battery cell over time.

[0091] Accordingly, the quality of a measured battery cell can be accurately and effectively predicted or determined in comparison with a reference battery cell. This is because the first voltage profile of the reference battery cell and the second voltage profile of the defective measured battery cell are different.

[0092] According to embodiments of the present invention, the precharge unit (100) can precharge the reference battery cell and the measured battery cell to a cutoff voltage. The good / bad judgment unit (300) calculates a first cutoff time (F1) for reaching the cutoff voltage or the highest voltage based on the first voltage profile, and calculates a second cutoff time (F2) for reaching the cutoff voltage or the highest voltage based on the second voltage profile, and when a value obtained by subtracting the second cutoff time (F2) from the first cutoff time (F1) is greater than a first threshold value (the first threshold value is a positive real number), the measured battery cell can be predicted or determined to be defective.

[0093] Accordingly, battery cells predicted to be defective or defective can be accurately, easily, and effectively identified. This is because the cutoff voltage (or peak voltage) reaching times of the good reference battery cell and the defective measured battery cell are different.

[0094] According to embodiments of the present invention, the good / bad judgment unit (300) calculates a first voltage change rate, which is a voltage change rate (dV / dT) at the beginning of precharge, based on the first voltage profile, and calculates a second voltage change rate (dV / dT), which is a voltage change rate at the beginning of precharge, based on the second voltage profile, and when a value obtained by subtracting the first voltage change rate from the second voltage change rate is greater than a second threshold value (the second threshold value is a positive real number), the measured battery cell can be predicted or determined to be defective.

[0095] Accordingly, battery cells predicted to be defective or defective can be accurately, easily, and effectively identified. This is because the voltage change rates at the initial precharge of the reference battery cell and the defective measured battery cell are different.

[0096] According to embodiments of the present invention, the good / bad judgment unit (300) calculates a first discrimination time (T1) for distinguishing between a first initial period (IS1), which is a time period at the beginning of pre-charge, based on the first voltage profile, and a first slowing period (GS1), which is a time period after the first initial period (IS1), adjacent to the first initial period (IS1), and having a voltage change rate (dV / dT) smaller than the voltage change rate in the first initial period (IS1), and calculates a second discrimination time (T2) for distinguishing between a second initial period (IS2), which is a time period at the beginning of pre-charge, based on the second voltage profile, and a second slowing period (GS2), which is a time period after the second initial period (IS2), adjacent to the second initial period (IS2), and having a voltage change rate smaller than the voltage change rate in the second initial period (IS2), and at the first discrimination time (T1), If the value obtained by subtracting the second discrimination time (T2) is greater than the third threshold (the third threshold is a positive real number), the measured battery cell can be predicted or determined to be defective.

[0097] Accordingly, battery cells predicted to be defective or defective can be accurately, easily, and effectively identified. This is because the time it takes for the voltage profiles of the reference battery cell and the defective measured battery cell to change from the initial section (IS) to the gradual section (GS) differs.

[0098] According to embodiments of the present invention, the reference profile may include a first differential profile relating to a differential value (dQ / dV or dV / dQ) obtained by differentiating a voltage-capacity profile relating to voltage and capacity of the reference battery cell. The measurement profile may include a second differential profile relating to a differential value (dQ / dV or dV / dQ) obtained by differentiating a voltage-capacity profile relating to voltage and capacity of the measured battery cell.

[0099] Accordingly, the quality of a measured battery cell can be accurately and effectively predicted or determined in comparison with a reference battery cell. This is because the first differential profile of the reference battery cell and the second differential profile of the defective measured battery cell are different.

[0100] According to embodiments of the present invention, the good / bad judgment unit (300) calculates the differential value corresponding to the first peak (P1) which is the main peak (P) or the first bottom which is the main bottom based on the first differential profile, and calculates the differential value corresponding to the second peak (P2) which corresponds to the first peak (P1) and is the main peak (P) or the second bottom which corresponds to the first bottom and is the main bottom based on the second differential profile, and when the value obtained by subtracting the differential value (dQ / dV) corresponding to the first peak (P1) from the differential value (dQ / dV) corresponding to the second peak (P2) is greater than a fourth threshold value (the fourth threshold value is a positive real number) or when the value obtained by subtracting the differential value (dV / dQ) corresponding to the second bottom from the differential value (dV / dQ) corresponding to the first bottom is greater than a fifth threshold value (the fifth threshold value is a positive real number), Measurement can predict or determine whether a battery cell is defective.

[0101] Accordingly, battery cells predicted to be defective or defective can be accurately, easily, and effectively identified. This is because the differential values ​​corresponding to the major peaks (P) or major bottoms in the differential profiles of the reference battery cell and the defective measured battery cell are different.

[0102] According to embodiments of the present invention, the good / bad judgment unit (300) obtains a first peak (P1) which is a main peak (P) or a first bottom which is a main bottom based on the first differential profile, determines whether a second peak (P2) which corresponds to the first peak (P1) and is a main peak (P) or a second bottom which corresponds to the first bottom and is a main bottom based on the second differential profile, or if the second peak (P2) or the second bottom exists, calculates the differential value corresponding to the second peak (P2) or the second bottom, and if the second peak (P2) or the second bottom does not exist or the differential value (dQ / dV) corresponding to the second peak (P2) is subtracted from the differential value (dQ / dV) corresponding to the first peak (P1), the differential value is greater than a sixth threshold value (the sixth threshold value is a positive real number) or the differential value corresponding to the second bottom is greater than a sixth threshold value. If the value obtained by subtracting the differential value (dV / dQ) corresponding to the first bottom from the differential value (dV / dQ) is greater than the seventh threshold value (the seventh threshold value is a positive real number), the measured battery cell can be predicted or determined to be defective.

[0103] Accordingly, a battery cell predicted to be defective or defective can be accurately, easily, and effectively identified. This is because, unlike the differential profile of a good reference battery cell, the differential profile of a defective measured battery cell does not have a major peak (P) or major bottom, or the differential values ​​corresponding to the major peak (P) or major bottom in the differential profiles of a good reference battery cell and a defective measured battery cell are different.

[0104] According to embodiments of the present invention, a battery cell activation method (S900) includes: a pre-charging process (S910) in which the pre-charging unit (100) pre-charges the battery cell, which may be in a pre-impregnation state before the electrolyte injected therein is sufficiently impregnated; a profile acquisition process (S920) in which the profile acquisition unit (200) acquires the profile regarding the voltage or capacity of the battery cell based on information measured while the battery cell is being pre-charged by the pre-charging unit (100); a quality determination process (S930) in which the quality determination unit (300) predicts or determines the quality of the battery cell based on the profile; an aging process (S940) in which the battery cell determined to be good in the quality determination process (S930) is aged; And the charging / discharging unit (400) may include a first charging process (S950) for charging the battery cell determined to be good in the good / bad determination process (S930).

[0105] Accordingly, defective or faulty battery cells can be detected in advance at the beginning of the activation process (immediately after the pre-charge process) before the aging process (S940). This prevents waste of time and money due to the lengthy aging process (S940) and / or the primary charging process (S950) being performed on defective or faulty battery cells. Consequently, the activation process efficiency can be improved, the manufacturing cost of battery cells can be reduced, production efficiency can be enhanced, and the failure rate can be reduced.

[0106] In addition, the cause of a battery cell failure can be correctly determined. For example, a battery cell that is phenomenologically a low-voltage failure but essentially an impregnation failure (e.g., due to insufficient electrolyte injection) can be correctly predicted or determined as an impregnation failure (e.g., due to insufficient electrolyte injection) rather than a low-voltage failure, unlike in the past. This is because, while a low-voltage failure is determined after the shipping charge or shipping discharge at the end of the activation process, an impregnation failure (e.g., due to insufficient electrolyte injection) can be predicted or determined before a low-voltage failure in the pass / fail determination process (S930) at the beginning of the activation process. Therefore, the fundamental cause of a battery cell failure can be correctly determined.

[0107] In addition to the effects described above, specific effects of the present invention are described below while explaining specific details for carrying out the invention.

[0108] Figure 1 is a block diagram of a battery cell activation system according to one embodiment of the present invention.

[0109] Figures 2 and 3 are graphs showing the voltage profile and differential profile for a good battery cell with a normal amount of electrolyte injected (“Good, 43g”) and a bad battery cell with a small amount of electrolyte injected (“Min, 20g”).

[0110] Figures 4 and 5 are graphs showing the voltage profile and differential profile for a good battery cell precharged immediately after electrolyte injection and a bad battery cell precharged after electrolyte injection and a long period of time.

[0111] Figure 6 is a flowchart of a battery cell activation method according to one embodiment of the present invention.

[0112] [Explanation of symbols]

[0113] 10: Battery cell activation system

[0114] 100: Pre-charge section 200: Profile acquisition section

[0115] 300: Distinguishing between positive and negative sides 400: Charging and discharging sides

[0116] F: Cutoff time

[0117] F1: First cut-off time F2: Second cut-off time

[0118] IS: Initial section

[0119] IS1: First initial period IS2: Second initial period

[0120] GS: Gentle section

[0121] GS1: First easing section GS2: Second easing section

[0122] T: Discrimination time

[0123] T1: First differentiation time T2: Second differentiation time

[0124] P: Main peak

[0125] P1: First peak P2: Second peak

[0126] U: Upper limit L: Lower limit

[0127] The above-described objects, features, and advantages will be described in detail below with reference to the accompanying drawings, so that those skilled in the art can easily practice the technical idea of ​​the present invention. In describing the present invention, if it is determined that a detailed description of known technologies related to the present invention may unnecessarily obscure the gist of the present invention, a detailed description thereof will be omitted. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

[0128] Although terms like "first" and "second" are used to describe various components, these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless otherwise specified, a "first" component may also be a "second" component.

[0129] Throughout the specification, unless otherwise specifically stated, each element may be singular or plural.

[0130] Hereinafter, the phrase "any configuration is placed on (or below)" a component or "on (or below)" a component may mean that any configuration is placed in contact with the upper surface (or lower surface) of said component, and that other configurations may be interposed between said component and any configuration placed on (or below) said component.

[0131] Additionally, when it is described that a component is "connected," "coupled," or "connected" to another component, it should be understood that the components may be directly connected or connected to one another, but that other components may also be "interposed" between the components, or that each component may be "connected," "coupled," or "connected" through another component.

[0132] As used herein, singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, terms such as "consisting of" or "comprising" should not necessarily be construed to include all of the components or steps described in the specification, and should be construed to mean that some of the components or steps may not be included, or that additional components or steps may be included.

[0133]

[0134] Fig. 1 is a block diagram of a battery cell activation system according to one embodiment of the present invention. Figs. 2 and 3 are graphs showing voltage profiles and differential profiles for a good battery cell with a normal amount of electrolyte injected (“Good, 43g”) and a defective battery cell with a small amount of electrolyte injected (“Min, 20g”). Figs. 4 and 5 are graphs showing voltage profiles and differential profiles for a good battery cell pre-charged immediately after electrolyte injection and a defective battery cell pre-charged after a long period of time after electrolyte injection. Fig. 6 is a flowchart of a battery cell activation method according to one embodiment of the present invention.

[0135]

[0136] [Battery Cell Activation System]

[0137] Referring to FIG. 1, a battery cell activation system (10) according to one embodiment may include a pre-charge unit (100), a profile acquisition unit (200), and a pass / fail determination unit (300). The battery cell activation system (10) may further include a charge / discharge unit (400).

[0138] The pre-charge unit (100) can pre-charge a battery cell that may be in a state prior to impregnation.

[0139] Here, impregnation may refer to the impregnation of the electrode assembly inside the battery cell with an electrolyte. The pre-impregnation state may refer to the state before the electrolyte injected into the inside of the battery cell is sufficiently impregnated.

[0140] Also, here, pre-charge may mean charging the battery cell in advance before the electrolyte is sufficiently impregnated into the electrode (before impregnation is complete). Pre-charging the battery cell before electrolyte impregnation (before the electrolyte is sufficiently impregnated) lowers the potential of the electrode (e.g., the negative electrode), thereby preventing foreign substances or metals such as Cu from being eluted from the electrode during electrolyte impregnation. Accordingly, low voltage defects (self-discharge abnormalities) of the battery cell due to eluted foreign metal substances can be prevented. Pre-charge may be performed by applying a low current to the battery cell.

[0141] The precharge unit (100) can precharge the battery cell up to a cutoff voltage. Here, the cutoff voltage can be, for example, 1.7 V.

[0142] The precharge unit (100) can precharge a reference battery cell, which is a battery cell in a state before impregnation, and a measurement battery cell, which is a battery cell that may be in a state before impregnation. Here, the reference battery cell may be a battery cell in a normal state (reference state) before being sufficiently impregnated with electrolyte. The reference battery cell may serve as a standard for determining whether the measurement battery cell is good or bad. If the measurement battery cell is precharged in a state where it is sufficiently impregnated, it may be determined to be bad.

[0143] The precharge unit (100) can precharge the reference battery cell and the measurement battery cell up to the cutoff voltage (Fig. 2, Fig. 4). Here, the cutoff voltage can be, for example, 1.7 V.

[0144] The precharge unit (100) can precharge the reference battery cell and the measurement battery cell in the same or similar manner. For example, the precharge unit (100) can precharge the reference and measurement battery cells to the same or similar cutoff voltage by applying a constant current at the same or similar rate (C-rate). From the time the electrolyte is injected into the reference battery cell and the measurement battery cell until the precharge is completed by the precharge unit (100), the environment in which the reference battery cell and the measurement battery cell are placed can be the same or similar. Here, the environment can be temperature or pressure, etc.

[0145] Accordingly, the quality of the measured battery cell can be accurately predicted or determined in comparison with the reference battery cell.

[0146] The precharge unit (100) can precharge a battery cell that may be in a state prior to aging. That is, the precharge unit (100) can precharge a battery cell in a state prior to impregnation prior to aging.

[0147] Accordingly, defective or predicted battery cells can be detected early in the activation process before aging. This prevents the waste of time and money due to lengthy activation processes (aging and / or charging / discharging) performed on predicted or predicted defective battery cells.

[0148] For example, the precharge unit (100) can precharge a reference battery cell in a pre-aging state and can precharge a measurement battery cell that may be in a pre-aging state. If a measurement battery cell in a post-aging state is precharged, it may be detected as defective.

[0149]

[0150] The profile acquisition unit (200) can acquire a profile regarding the voltage or capacity of the battery cell based on information measured while the battery cell is being precharged by the precharge unit (100).

[0151] Here, the measured information may be information about the voltage or capacity (charge amount) of the battery cell over time.

[0152] The profile may include a voltage profile of the battery cell voltage over time (Figs. 2 and 4). Accordingly, the quality or failure of a battery cell can be accurately and effectively predicted or determined. This is because the voltage profiles of good and defective battery cells differ.

[0153] The profile may include a differential profile regarding the differential value (dQ / dV or dV / dQ) obtained by differentiating the voltage-capacity profile regarding the voltage and capacity of the battery cell (Fig. 3, Fig. 5). The differential profile may represent the differential value (dQ / dV or dV / dQ) according to voltage, capacity, or time. Accordingly, the quality or failure of the battery cell can be accurately and effectively predicted or determined. This is because the differential profiles of a good battery cell and a defective battery cell are different.

[0154] The profile may also include a voltage-capacity profile (e.g., capacity as a function of voltage).

[0155] The profile acquisition unit (200) can acquire a reference profile and a measurement profile (Figs. 2 to 5). The reference profile may be a profile for a reference battery cell. The measurement profile may be a profile for a measured battery cell.

[0156] The reference profile may include a first voltage profile relating to the voltage of the reference battery cell over time. Additionally, the measurement profile may include a second voltage profile relating to the voltage of the measurement battery cell over time (FIGS. 2, 4).

[0157] Accordingly, the quality of a measured battery cell can be accurately and effectively predicted or determined in comparison with a reference battery cell. This is because the first voltage profile of the reference battery cell and the second voltage profile of the defective measured battery cell are different.

[0158] The reference profile may include a first differential profile. The first differential profile may be a profile relating to a differential value (dQ / dV or dV / dQ) obtained by differentiating a voltage-capacity profile relating to voltage and capacity of a reference battery cell. In addition, the measurement profile may include a second differential profile. The second differential profile may be a profile relating to a differential value (dQ / dV or dV / dQ) obtained by differentiating a voltage-capacity profile relating to voltage and capacity of a measured battery cell.

[0159] Accordingly, the quality of a measured battery cell can be accurately and effectively predicted or determined in comparison with a reference battery cell. This is because the first differential profile of the reference battery cell and the second differential profile of the defective measured battery cell are different.

[0160]

[0161] The quality determination unit (300) can predict or determine the quality of a battery cell based on the profile obtained from the profile acquisition unit (200).

[0162] In this way, the battery cell activation system (10) may include a pre-charge unit (100), a profile acquisition unit (200), and a pass / fail determination unit (300). Accordingly, a battery cell predicted to be defective or defective can be detected in advance in the early stage of the activation process (after pre-charge) before the aging process in which the battery cell is aged for a long period of time so that the electrolyte is sufficiently impregnated into the electrode assembly. Accordingly, it is possible to prevent a long-term activation process (aging and / or charge / discharge) from being performed on a battery cell predicted to be defective or defective, resulting in wasted time and money. Accordingly, the activation process efficiency can be improved, the manufacturing cost of the battery cell can be reduced, the production efficiency can be improved, and the defect rate can be lowered.

[0163] In addition, the cause of a battery cell defect can be correctly determined. For example, a battery cell that is phenomenologically a low-voltage defect but essentially an impregnation defect (e.g., due to insufficient electrolyte injection amount) can be correctly predicted or determined as an impregnation defect (e.g., due to insufficient electrolyte injection amount) rather than a low-voltage defect, unlike in the past. This is because a low-voltage defect is determined after the shipping charge or shipping discharge at the end of the activation process, but an impregnation defect (e.g., due to insufficient electrolyte injection amount) can be predicted or determined by the pass / fail determination unit (300) before a low-voltage defect at the beginning of the activation process. Accordingly, the essential cause of a battery cell defect can be correctly determined.

[0164] The good / bad judgment unit (300) can predict or judge the good / bad of a measured battery cell based on a reference profile and a measurement profile.

[0165] Accordingly, the quality of the measured battery cell can be accurately and easily predicted or determined by comparing it with the reference battery cell.

[0166] In this regard, let us look at two examples as follows.

[0167] In one embodiment, if the electrolyte injection amount of the measured battery cell is less than the electrolyte injection amount of the reference battery cell, the measured battery cell may not only be defective in itself, but may also be determined to have impregnation failure and / or low voltage failure after the measured battery cell is aged. In the present invention, impregnation failure and / or low voltage failure of the measured battery cell due to insufficient electrolyte injection amount before aging can be predicted or determined in advance using the voltage profile (second voltage profile) acquired during pre-charging of the measured battery cell.

[0168] In another embodiment, if the precharge waiting time (time from electrolyte injection to precharge) of the measured battery cell is longer than the precharge waiting time of the reference battery cell, the electrolyte of the measured battery cell is sufficiently impregnated (e.g., impregnation is completed) before the measured battery cell is precharged, so that foreign substances or metals such as Cu are eluted from the electrodes of the measured battery cell during impregnation, and the measured battery cell can be determined to be a low-voltage defect at the end of the activation process after aging. In the present invention, the low-voltage defect of the measured battery cell due to the increase in the precharge waiting time before aging can be predicted in advance by using the voltage profile (second voltage profile) acquired during the precharge of the measured battery cell.

[0169] The good / bad judgment unit (300) can calculate the cutoff voltage or the cutoff time (F) for reaching the maximum voltage based on the voltage profile. The good / bad judgment unit (300) can predict or determine the good / bad of a battery cell based on the cutoff time (F).

[0170] Accordingly, the quality of battery cells can be accurately, easily, and effectively determined. This is because the times required for good and defective battery cells to reach the cutoff voltage (or peak voltage) differ.

[0171] Specifically, for example, the pass / fail judgment unit (300) can calculate the first cut-off voltage or the first cut-off time (F1) for reaching the highest voltage based on the first voltage profile. For example, the pass / fail judgment unit (300) can calculate n cut-off voltages or the highest voltage reaching times from n first voltage profiles obtained from n (n is a natural number greater than or equal to 2) reference battery cells and set their average value as the first cut-off time (F1) (FIGS. 2, 4).

[0172] In addition, the positive / negative judgment unit (300) can calculate the second cutoff time (F2) for reaching the cutoff voltage or the highest voltage based on the second voltage profile (Fig. 2, Fig. 4).

[0173] The good / bad judgment unit (300) can predict or determine that the measured battery cell is defective if the value obtained by subtracting the second cut-off time (F2) from the first cut-off time (F1) is greater than the first threshold value (the first threshold value is a positive real number).

[0174] Accordingly, battery cells predicted to be defective or defective can be accurately, easily, and effectively identified. This is because the cutoff voltage (or peak voltage) reaching times of the good reference battery cell and the defective measured battery cell are different.

[0175] In this regard, let us look at two examples as follows.

[0176] In one embodiment, a measured battery cell having a small electrolyte injection amount has a smaller actual capacity than a reference battery cell having a normal electrolyte injection amount, and thus can reach the cut-off voltage faster than the reference battery cell during precharge (i.e., second cut-off time (F2) < first cut-off time (F1), FIG. 2 ). Accordingly, when the measured battery cell reaches the cut-off voltage sufficiently faster than the reference battery cell (i.e., first cut-off time (F1) - second cut-off time (F2) > first threshold value), the measured battery cell can be determined to be defective due to insufficient electrolyte injection amount, and it can be predicted in advance that the measured battery cell will be determined to be defective due to impregnation failure and / or low voltage failure after aging.

[0177] In another embodiment, a measurement battery cell having a sufficiently long precharge standby time can reach the cutoff voltage faster than the reference battery cell during precharge because the electrolyte is better impregnated and the charging speed is faster than that of the reference battery cell with a normal precharge standby time (i.e., the second cutoff time (F2) < the first cutoff time (F1), FIG. 4). Accordingly, when the measurement battery cell reaches the cutoff voltage sufficiently faster than the reference battery cell (i.e., the first cutoff time (F1) - the second cutoff time (F2) > the first threshold value), it can be predicted that the measurement battery cell will be determined to have a low-voltage defect due to metal dissolution after aging.

[0178] Meanwhile, the good / bad judgment unit (300) can also predict or judge as defective a measured battery cell whose second cut-off time (F2) is less than a preset value.

[0179] The battery precharge determination unit (300) can calculate the voltage change rate at the beginning of the precharge based on the voltage profile. Here, the initial precharge may be the initial period (IS) described later. The voltage change rate (dV / dT) may be an instantaneous voltage change rate or an average voltage change rate.

[0180] The good / bad judgment unit (300) can predict or judge the good / bad of a battery cell based on the voltage change rate.

[0181] Accordingly, the quality of battery cells can be accurately, easily, and effectively determined. This is because the voltage change rates at the initial precharge stage of good and defective battery cells differ.

[0182] Specifically, for example, the good / bad judgment unit (300) can calculate the first voltage change rate, which is the voltage change rate (dV / dT) at the beginning of the precharge, based on the first voltage profile. For example, the good / bad judgment unit (300) can calculate n voltage change rates (dV / dT) at the beginning of the precharge from n first voltage profiles obtained from n (n is a natural number greater than or equal to 2) reference battery cells, and set their average value as the first voltage change rate.

[0183] The positive / negative judgment unit (300) can calculate the second voltage change rate (dV / dT), which is the voltage change rate at the beginning of the precharge, based on the second voltage profile.

[0184] The good / bad judgment unit (300) can predict or determine that the measured battery cell is defective if the value obtained by subtracting the first voltage change rate from the second voltage change rate is greater than the second threshold value (the second threshold value is a positive real number).

[0185] Accordingly, battery cells predicted to be defective or defective can be accurately, easily, and effectively identified. This is because the voltage change rates at the initial precharge of the reference battery cell and the defective measured battery cell are different.

[0186] In this regard, let us look at one example:

[0187] In one embodiment, a measured battery cell having a small electrolyte injection amount may have a smaller actual capacity than a reference battery cell having a normal electrolyte injection amount, and thus may have a larger initial voltage change rate than the reference battery cell during precharge (i.e., second voltage change rate > first voltage change rate, FIG. 2 ). Accordingly, when the measured battery cell has a sufficiently larger initial voltage change rate than the reference battery cell (i.e., second voltage change rate - first voltage change rate > second threshold value), the measured battery cell may be determined to be defective due to insufficient electrolyte injection amount and may be predicted in advance to be determined to be defective after aging.

[0188] Meanwhile, the good / bad judgment unit (300) can predict or judge that a measured battery cell having a second voltage change rate greater than a preset value is defective due to insufficient electrolyte injection amount.

[0189] The positive / negative judgment unit (300) can calculate a distinction time (T) that distinguishes between the initial section (IS), which is the initial time section of the precharge, and the gradual section (GS), or calculate the slope of the gradual section (GS) based on the voltage profile.

[0190] Here, the gradual section (GS) is a time section after the initial section (IS), is adjacent to the initial section (IS), and may be a time section in which the rate of change of voltage (dV / dT) is smaller than the rate of change of voltage in the initial section (IS).

[0191] For example, the rate of change of voltage in the initial section (IS) and the smoothing section (GS) may be the average value of the rate of change of voltage over time in each section. The rate of change of voltage over time in the initial section (IS) and the smoothing section (GS) may mostly exist within a predetermined range based on a reference value (e.g., the average value of the rate of change of voltage). The rate of change of voltage in the smoothing section (GS) may be a predetermined value or a predetermined degree or more less than the rate of change of voltage in the initial section (IS).

[0192] Also, here, the slope of the smooth section (GS) can be the average value of the slope over time in the smooth section (GS).

[0193] The good / bad judgment unit (300) can predict or judge the good / bad of a battery cell based on the discrimination time (T) or the slope of the smooth section (GS).

[0194] Accordingly, the quality of a battery cell can be accurately, easily, and effectively determined. This is because the time it takes for a good battery cell to transition from the initial section (IS) to the gradual section (GS) in the voltage profiles of a good battery cell to the gradual section (GS) differs, and the slope (dV / dT) of the gradual section (GS) differs.

[0195] A specific example regarding the distinction time (T) is as follows. The good / bad judgment unit (300) can calculate the first distinction time (T1) that distinguishes between the first initial period (IS1), which is a time period in the early stage of precharge, and the first slow period (GS1) based on the first voltage profile (Fig. 2). Here, the first slow period (GS1) is a time period after the first initial period (IS1), is adjacent to the first initial period (IS1), and may be a time period in which the voltage change rate (dV / dT) is smaller than the voltage change rate in the first initial period (IS1). For example, the good / bad judgment unit (300) can calculate n distinction times (T) for distinguishing between n initial sections (IS) and smooth sections (GS) from n first voltage profiles obtained from n (n is a natural number greater than or equal to 2) reference battery cells, and set the average value of the n distinction times (T) as the first distinction time (T1).

[0196] In addition, the positive / negative judgment unit (300) can calculate a second distinction time (T2) that distinguishes between the second initial period (IS2), which is a time period in the early stage of precharge, and the second slow period (GS2) based on the second voltage profile (Fig. 2). Here, the second slow period (GS2) is a time period after the second initial period (IS2), is adjacent to the second initial period (IS2), and may be a time period in which the rate of change in voltage is smaller than the rate of change in voltage in the second initial period (IS2).

[0197] The good / bad judgment unit (300) can predict or determine that the measured battery cell is defective if the value obtained by subtracting the second judgment time (T2) from the first judgment time (T1) is greater than the third threshold value (the third threshold value is a positive real number).

[0198] Accordingly, battery cells predicted to be defective or defective can be accurately, easily, and effectively identified. This is because the time it takes for the voltage profiles of the reference battery cell and the defective measured battery cell to change from the initial section (IS) to the gradual section (GS) differs.

[0199] In this regard, an example is as follows. In one example, a measured battery cell having a small electrolyte injection amount has a smaller actual capacity than a reference battery cell having a normal electrolyte injection amount, and thus may change from the initial section (IS) to the gradual section (GS) faster than the reference battery cell during precharge (i.e., the second discrimination time (T2) < the first discrimination time (T1)). Accordingly, when the measured battery cell changes from the initial section (IS) to the gradual section (GS) sufficiently faster than the reference battery cell (i.e., the first discrimination time (T1) - the second discrimination time (T2) > the third threshold value), the measured battery cell may be determined to be defective due to insufficient electrolyte injection amount and may be predicted in advance to be determined to be defective after aging.

[0200] Meanwhile, the good / bad judgment unit (300) can predict or judge that a measured battery cell with a second judgment time (T2) shorter than a preset value is defective due to insufficient electrolyte injection amount.

[0201] A specific example regarding the slope of the smoothing section (GS) is as follows. Since the measured battery cell with a small electrolyte injection amount has a smaller actual capacity than the reference battery cell with a normal electrolyte injection amount, the slope (dV / dT) of the second smoothing section (GS2) may be smaller overall than the slope (dV / dT) of the first smoothing section (GS1) (Fig. 2). Accordingly, when the slope (dV / dT) of the second smoothing section (GS2) is sufficiently smaller than the slope (dV / dT) of the first smoothing section (GS1) (i.e., slope of the first smoothing section (GS1) - slope of the second smoothing section (GS2) > a predetermined threshold value), the measured battery cell may be determined to be defective due to insufficient electrolyte injection amount or may be predicted in advance to be determined to be defective after aging.

[0202] Meanwhile, the good / bad judgment unit (300) can predict or judge that a measured battery cell having a slope of the second gradual section (GS2) smaller than a preset value is defective due to insufficient electrolyte injection amount.

[0203]

[0204] The positive / negative judgment unit (300) can determine whether a major peak (P) or a major bottom exists based on a differential profile, or, if a major peak (P) or a major bottom exists, can calculate a differential value corresponding to the major peak (P) or the major bottom.

[0205] Here, the main peak (P) may be the peak of a main mountain section having a width (interval) greater than a predetermined size in the differential profile. The differential value in the main mountain section may increase and then decrease overall. If the main mountain section has multiple peaks, the main peak (P) may be the peak (characteristic peak) of a line connecting the multiple peaks. Similarly, the main bottom may be the bottom of a main valley section having a width greater than a predetermined size in the differential profile. The differential value in the main valley section may decrease and then increase overall. If the main valley section has multiple bottoms, the main bottom may be the bottom (characteristic bottom) of a line connecting the multiple bottoms.

[0206] For example, the pass / fail determination unit (300) can determine whether a major peak (P) or a major bottom exists in a predetermined section (e.g., a predetermined section of the X-axis) for voltage, capacity, or time based on a differential profile. If a major peak (P) or a major bottom exists in the predetermined section, the pass / fail determination unit (300) can calculate a differential value corresponding to the major peak (P) or the major bottom. Here, the predetermined section for voltage, capacity, or time may be a section for voltage, capacity, or time that partially overlaps with or is adjacent to the first smooth section (GS1) described above.

[0207] The good / bad judgment unit (300) can predict or judge the good / bad of a battery cell based on the presence or absence of a major peak (P) or major bottom or the differential value corresponding to the major peak (P) or major bottom.

[0208] Accordingly, the quality of a battery cell can be accurately, easily, and effectively determined. This is because, unlike the differential profile of a good battery cell, the differential profile of a defective battery cell does not have a major peak (P) or major bottom, or the differential values ​​corresponding to the major peak (P) or major bottom in the differential profiles of a good battery cell and a defective battery cell are different.

[0209] In a specific embodiment, the pass / fail judgment unit (300) can calculate a differential value corresponding to the first peak (P1), which is a main peak (P), or the first bottom, which is a main bottom, based on the first differential profile. For example, the pass / fail judgment unit (300) can calculate differential values ​​(dQ / dV) corresponding to n main peaks (P) from n first voltage profiles obtained from n (n is a natural number greater than or equal to 2) reference battery cells and set their average value as the differential value (dQ / dV) corresponding to the first peak (P1), or can calculate differential values ​​(dV / dQ) corresponding to n main bottoms and set their average value as the differential value (dV / dQ) corresponding to the first bottom.

[0210] The second differential profile-based differential determination unit (300) can calculate a differential value corresponding to the first peak (P1) and the second peak (P2), which is the main peak (P), or corresponding to the first bottom and the second bottom, which is the main bottom.

[0211] Here, the second peak (P2) corresponding to the first peak (P1) may mean the second peak (P2) adjacent to the first peak (P1) in terms of voltage, capacity, or time (i.e., for example, along the X-axis). Similarly, the second bottom corresponding to the first bottom may mean the second bottom adjacent to the first bottom in terms of voltage, capacity, or time (i.e., for example, along the X-axis).

[0212] The good / bad judgment unit (300) can predict or determine that the measured battery cell is defective when the value obtained by subtracting the differential value (dQ / dV) corresponding to the first peak (P1) from the differential value (dQ / dV) corresponding to the second peak (P2) is greater than the fourth threshold value (the fourth threshold value is a positive real number) or when the value obtained by subtracting the differential value (dV / dQ) corresponding to the second bottom from the differential value (dV / dQ) corresponding to the first bottom is greater than the fifth threshold value (the fifth threshold value is a positive real number).

[0213] Accordingly, battery cells predicted to be defective or defective can be accurately, easily, and effectively identified. This is because the differential values ​​corresponding to the major peaks (P) or major bottoms in the differential profiles of the reference battery cell and the defective measured battery cell are different.

[0214] In this regard, let us look at one example:

[0215] In one embodiment, since a measured battery cell having a small electrolyte injection amount has a smaller actual capacity than a reference battery cell having a normal electrolyte injection amount, the slope (dV / dT) of the second smoothing section (GS2) described above may be smaller overall than the slope (dV / dT) of the first smoothing section (GS1) described above during precharge (Fig. 2). Accordingly, the differential value (dQ / dV) of the second peak (P2) corresponding to the second smoothing section (GS2) may be larger than the differential value (dQ / dV) of the first peak (P1) corresponding to the first smoothing section (GS1) (Fig. 3), or the differential value (dV / dQ) of the second bottom corresponding to the second smoothing section (GS2) may be smaller than the differential value (dV / dQ) of the first bottom corresponding to the first smoothing section (GS1). Accordingly, when the derivative (dQ / dV) of the second peak (P2) is sufficiently greater than the derivative (dQ / dV) of the first peak (P1) (i.e., derivative of the second peak - derivative of the first peak > fourth threshold, FIG. 3) or the derivative (dV / dQ) of the second bottom is sufficiently smaller than the derivative (dV / dQ) of the first bottom (i.e., derivative of the first bottom - derivative of the second bottom > fifth threshold), the measured battery cell can be determined to be defective due to insufficient electrolyte injection amount and can be predicted in advance to be determined to be defective after aging.

[0216] Meanwhile, the good / bad judgment unit (300) can predict or determine that a measured battery cell in which the differential value (dQ / dV) of the second peak (P2) is greater than a preset value or the differential value of the second bottom is less than a preset value is defective due to insufficient electrolyte injection amount. This is related to the upper limit value (U) described below.

[0217] In another specific embodiment, the positive / negative judgment unit (300) can obtain the first peak (P1), which is the main peak (P), or the first bottom, which is the main bottom, based on the first differential profile.

[0218] In addition, the second differential profile determination unit (300) can determine whether a second peak (P2) or a second bottom exists based on the second differential profile. Here, the second peak (P2) may be a main peak (P) corresponding to the first peak (P1), and the second bottom may be a main bottom corresponding to the first bottom.

[0219] For example, the second differential profile-based determination unit (300) can determine whether a second peak (P2) or a second bottom exists in a predetermined section (e.g., a predetermined section of the X-axis) regarding voltage, capacity, or time. Here, the predetermined section regarding voltage, capacity, or time may be a section regarding voltage, capacity, or time that partially overlaps with or is adjacent to the first gradual section (GS1) described above (FIGS. 2 and 3).

[0220] In addition, the positive / negative judgment unit (300) can calculate a differential value corresponding to the second peak (P2) or the second bottom when the second peak (P2) or the second bottom exists.

[0221] The good / bad judgment unit (300) can predict or determine that the measured battery cell is defective when the second peak (P2) or the second bottom does not exist (Fig. 5), or when the value obtained by subtracting the differential value (dQ / dV) corresponding to the second peak (P2) from the differential value (dQ / dV) corresponding to the first peak (P1) is greater than the sixth threshold value (the sixth threshold value is a positive real number), or when the value obtained by subtracting the differential value (dV / dQ) corresponding to the first bottom from the differential value (dV / dQ) corresponding to the second bottom is greater than the seventh threshold value (the seventh threshold value is a positive real number).

[0222] Accordingly, a battery cell predicted to be defective or defective can be accurately, easily, and effectively identified. This is because, unlike the differential profile of a good reference battery cell, the differential profile of a defective measured battery cell does not have a major peak (P) or major bottom, or the differential values ​​corresponding to the major peak (P) or major bottom in the differential profiles of a good reference battery cell and a defective measured battery cell are different.

[0223] In this regard, let us look at one example:

[0224] In one embodiment, a measured battery cell having a sufficiently long precharge standby time may have a faster charging speed due to better electrolyte impregnation than a reference battery cell having a normal precharge standby time, and thus a major peak (P) or a major bottom may not exist in the differential profile during precharge, or even if it exists, the degree of vertical protrusion may be smaller than that of the major peak (P) or the major bottom of the reference battery cell. Accordingly, if a major peak (P) or a major bottom does not exist in the differential profile of the measured battery cell, or even if it exists, the degree of vertical protrusion may be sufficiently small (i.e., derivative of the first peak - derivative of the second peak > the sixth threshold or derivative of the second bottom - derivative of the first bottom > the seventh threshold), it can be predicted that the measured battery cell will be determined to have a low-voltage failure due to metal dissolution after aging.

[0225] Meanwhile, the good / bad judgment unit (300) can also predict a measured battery cell in which the differential value (dQ / dV) of the second peak (P2) is smaller than a preset value or the differential value of the second bottom is larger than a preset value as a low-voltage defective cell. This is related to the lower limit value (L) described below.

[0226] The good / bad judgment unit (300) can predict or determine that a battery cell is defective if the differential value (dQ / dV) corresponding to the main peak (P) is greater than the upper limit (U, the upper limit is a positive real number) or less than the lower limit (L, the lower limit is a positive real number smaller than the upper limit), or if the differential value (dV / dQ) corresponding to the main bottom is greater than the multiplicative inverse of the lower limit (L) or less than the multiplicative inverse of the upper limit (U).

[0227] For example, the good / bad judgment unit (300) can predict or determine that a measured battery cell having a second peak (P2) or a second bottom is defective if the differential value (dQ / dV) corresponding to the second peak (P2) is greater than the upper limit (U) or less than the lower limit (L), or if the differential value (dV / dQ) corresponding to the second bottom is greater than the reciprocal of the lower limit (L) or less than the reciprocal of the upper limit (U).

[0228] Specifically, a measuring battery cell having a small electrolyte injection amount may have a differential value (dQ / dV) corresponding to the second peak (P2) that is greater than the upper limit (U) (Fig. 3) or a differential value (dV / dQ) corresponding to the second bottom that is less than the reciprocal of the upper limit (U). Although not shown in Fig. 5, a measuring battery cell having a large precharge standby time may have a differential value (dQ / dV) corresponding to the second peak (P2) that is less than the lower limit (L) or a differential value (dV / dQ) corresponding to the second bottom that is greater than the reciprocal of the lower limit (L).

[0229] Accordingly, the quality of the battery cell can be accurately, easily and effectively determined.

[0230] The upper limit (U) and lower limit (L) can be set based on the differential value corresponding to the first peak (P1) or the first bottom.

[0231] The upper limit (U) can be greater than or equal to 0.04 mAh / mV and less than or equal to 0.06 mAh / mV. The upper limit (U) can be greater than or equal to 0.05 mAh / mV. The lower limit (L) can be greater than or equal to 0.01 mAh / mV and less than or equal to 0.03 mAh / mV. The lower limit (L) can be greater than or equal to 0.02 mAh / mV.

[0232] Accordingly, the quality of the battery cell can be accurately determined.

[0233]

[0234] The charging / discharging unit (400) can charge or discharge a battery cell sufficiently impregnated with electrolyte (impregnation completed).

[0235] The charging / discharging unit (400) can charge the battery cell up to the cutoff voltage. Here, the cutoff voltage can be, for example, 4.2 V.

[0236] A SEI (Solid Electrolyte Interface) film can be formed on the surface of the electrode (e.g., negative electrode) of the battery cell by charging the charging / discharging unit (400).

[0237]

[0238] [How to activate battery cells]

[0239] Referring to FIG. 6, a battery cell activation method (S900) according to one embodiment may include a pre-charging process (S910), a profile acquisition process (S920), a pass / fail determination process (S930), an aging process (S940), and a first charging process (S950).

[0240] In the pre-charge process (S910), the pre-charge unit (100) can pre-charge a battery cell that may be in a pre-impregnation state, that is, a state before the electrolyte injected inside is sufficiently impregnated.

[0241] In the profile acquisition process (S920), the profile acquisition unit (200) can acquire the profile regarding the voltage or capacity of the battery cell based on information measured while the battery cell is being precharged by the precharge unit (100).

[0242] In the good / bad judgment process (S930), the good / bad judgment unit (300) can predict or judge the good / bad of the battery cell based on the profile.

[0243] In the aging process (S940), battery cells determined to be good in the good-bad judgment process (S930) can be aged.

[0244] For example, the aging process (S940) may include a primary aging process (pre-aging). The aging process (S940) may include a secondary aging process.

[0245] The primary aging process can be performed before the primary charging process (S950). During the primary aging process, the electrolyte of the battery cell can be sufficiently impregnated (impregnation completed) into the electrode assembly.

[0246] The secondary aging process can be performed after the primary charging process (S950) described below. During the secondary aging process, the SEI film formed on the electrode surface of the battery cell can be stabilized.

[0247] In the first charging process (S950), the charging / discharging unit (400) can charge the battery cells that are determined to be good in the good / bad judgment process (S930).

[0248] The first charging process (S950) may be performed after the first aging process (pre-aging process). During the first charging process (S950), a solid electrolyte interface (SEI) film may be formed on the surface of the electrode (e.g., the negative electrode) of the battery cell. The cutoff voltage of the first charging process (S950) may be higher than the cutoff voltage of the pre-charging process (S910).

[0249] Accordingly, defective or faulty battery cells can be detected in advance at the beginning of the activation process (immediately after the pre-charge process) before the aging process (S940). This prevents waste of time and money due to the lengthy aging process (S940) and / or the primary charging process (S950) being performed on defective or faulty battery cells. Consequently, the activation process efficiency can be improved, the manufacturing cost of battery cells can be reduced, production efficiency can be enhanced, and the failure rate can be reduced.

[0250] In addition, the cause of a battery cell failure can be correctly determined. For example, a battery cell that is phenomenologically a low-voltage failure but essentially an impregnation failure (e.g., due to insufficient electrolyte injection) can be correctly predicted or determined as an impregnation failure (e.g., due to insufficient electrolyte injection) rather than a low-voltage failure, unlike in the past. This is because, while a low-voltage failure is determined after the shipping charge or shipping discharge at the end of the activation process, an impregnation failure (e.g., due to insufficient electrolyte injection) can be predicted or determined before a low-voltage failure in the pass / fail determination process (S930) at the beginning of the activation process. Therefore, the fundamental cause of a battery cell failure can be correctly determined.

[0251] Meanwhile, matters not mentioned in relation to the pre-charge unit (100), profile acquisition unit (200), and pass / fail determination unit (300) of each process of the battery cell activation method (S900) can be inferred from the battery cell activation system (10) described above.

[0252]

[0253] It should be understood that the above-described embodiments are illustrative in all respects and not restrictive, and the scope of the present invention will be determined by the claims that follow rather than by the detailed description set forth above. Furthermore, the meaning and scope of the claims that follow, as well as all variations and modifications derived from their equivalent concepts, should be construed as encompassing the scope of the present invention.

[0254] Although the present invention has been described with reference to the drawings exemplified above, it is to be understood that the present invention is not limited to the embodiments and drawings disclosed herein, and that various modifications may be made by those skilled in the art within the scope of the technical idea of ​​the present invention. Furthermore, even if the operational effects according to the configuration of the present invention have not been explicitly described while describing the embodiments of the present invention, it is natural that the effects predictable by the corresponding configuration should also be acknowledged.

Claims

1. A pre-charge unit (100) that pre-charges a battery cell that may be in a pre-impregnation state before the electrolyte injected inside is sufficiently impregnated; A profile acquisition unit (200) that acquires a profile regarding the voltage or capacity of the battery cell based on information measured while the battery cell is being precharged by the precharge unit (100); and Including a quality determination unit (300) that predicts or determines the quality of the battery cell based on the above profile. Battery cell activation system.

2. In claim 1, The above pre-charge unit (100) is a battery cell activation system that pre-charges the battery cell, which may be in a state before aging.

3. In claim 1 or claim 2, A battery cell activation system, wherein the above profile includes a voltage profile regarding the voltage of the battery cell over time.

4. In claim 3, The above precharge unit (100) precharges the battery cell to the cutoff voltage, The above-mentioned good / bad judgment unit (300) calculates the cutoff time (F) for reaching the cutoff voltage or the highest voltage based on the voltage profile, and predicts or determines the good / bad of the battery cell based on the cutoff time (F).

5. In claim 3, The above-mentioned good / bad judgment unit (300) is a battery cell activation system that calculates the voltage change rate at the beginning of the pre-charge based on the voltage profile and predicts or determines the good / bad of the battery cell based on the voltage change rate.

6. In claim 3, The above-mentioned quality judgment unit (300) calculates a discrimination time (T) for distinguishing between an initial section (IS), which is a time section at the beginning of the precharge, based on the voltage profile, and a smooth section (GS), which is a time section after the initial section (IS), adjacent to the initial section (IS), and in which the rate of change of voltage (dV / dT) is smaller than the rate of change of voltage in the initial section (IS), or calculates the slope of the smooth section (GS), and predicts or determines the quality of the battery cell based on the discrimination time (T) or the slope of the smooth section (GS).

7. In any one of claims 1 to 6, A battery cell activation system, wherein the above profile includes a differential profile regarding a differential value (dQ / dV or dV / dQ) obtained by differentiating a voltage-capacity profile regarding voltage and capacity of the battery cell.

8. In claim 7, The above-mentioned good / bad judgment unit (300) determines whether a main peak (P) or a main bottom exists based on the differential profile, or if the main peak (P) or the main bottom exists, calculates the differential value corresponding to the main peak (P) or the main bottom, and predicts or determines whether the battery cell is good / bad based on the presence of the main peak (P) or the main bottom or the differential value corresponding to the main peak (P) or the main bottom. A battery cell activation system.

9. In claim 8, The above-mentioned good / bad judgment unit (300) is a battery cell activation system that predicts or determines the battery cell as defective if the differential value (dQ / dV) corresponding to the main peak (P) is greater than an upper limit (U, the upper limit is a positive real number) or less than a lower limit (L, the lower limit is a positive real number less than the upper limit), or if the differential value (dV / dQ) corresponding to the main bottom is greater than a multiplicative inverse of the lower limit (L) or less than a multiplicative inverse of the upper limit (U).

10. In claim 9, A battery cell activation system, wherein the upper limit (U) is 0.04 mAh / mV or more and 0.06 mAh / mV or less, or the lower limit (L) is 0.01 mAh / mV or more and 0.03 mAh / mV or less.

11. In claim 1, The above precharge unit (100) precharges the reference battery cell, which is the battery cell in the pre-impregnation state, and the measurement battery cell, which is the battery cell that may be in the pre-impregnation state. The above profile acquisition unit (200) acquires the reference profile and the measurement profile, which are the profiles for each of the reference battery cell and the measurement battery cell, respectively, The above-mentioned good / bad judgment unit (300) is a battery cell activation system that predicts or determines the good / bad of the measured battery cell based on the reference profile and the measurement profile.

12. In claim 11, A battery cell activation system in which the above precharge unit (100) precharges the reference battery cell and the measurement battery cell in the same or similar manner, or the environment in which the reference battery cell and the measurement battery cell are placed is the same or similar from the time the electrolyte is injected into the reference battery cell and the measurement battery cell until the precharge is completed by the above precharge unit (100).

13. In claim 11 or claim 12, The above reference profile includes a first voltage profile regarding the voltage of the reference battery cell over time, A battery cell activation system, wherein the measurement profile comprises a second voltage profile relating to the voltage of the measured battery cell over time.

14. In claim 13, The above precharge unit (100) precharges the reference battery cell and the measurement battery cell to the cutoff voltage, The above-mentioned good / bad judgment unit (300) calculates a first cut-off time (F1) for reaching the cut-off voltage or the highest voltage based on the first voltage profile, calculates a second cut-off time (F2) for reaching the cut-off voltage or the highest voltage based on the second voltage profile, and predicts or determines the measured battery cell as defective when the value obtained by subtracting the second cut-off time (F2) from the first cut-off time (F1) is greater than a first threshold value (the first threshold value is a positive real number). A battery cell activation system.

15. In claim 13, The above-mentioned good / bad judgment unit (300) calculates a first voltage change rate, which is a voltage change rate (dV / dT) at the beginning of precharge, based on the first voltage profile, and calculates a second voltage change rate (dV / dT), which is a voltage change rate at the beginning of precharge, based on the second voltage profile, and predicts or determines the measured battery cell as defective when the value obtained by subtracting the first voltage change rate from the second voltage change rate is greater than a second threshold value (the second threshold value is a positive real number). A battery cell activation system.

16. In claim 13, The above-mentioned good / bad judgment unit (300) calculates a first discrimination time (T1) for distinguishing between a first initial period (IS1), which is a time period at the beginning of pre-charge, based on the first voltage profile, and a first slowing period (GS1), which is a time period after the first initial period (IS1), adjacent to the first initial period (IS1), and having a voltage change rate (dV / dT) smaller than the voltage change rate in the first initial period (IS1), and calculates a second discrimination time (T2) for distinguishing between a second initial period (IS2), which is a time period at the beginning of pre-charge, based on the second voltage profile, and a second slowing period (GS2), which is a time period after the second initial period (IS2), adjacent to the second initial period (IS2), and having a voltage change rate smaller than the voltage change rate in the second initial period (IS2), and at the first discrimination time (T1), A battery cell activation system that predicts or determines the measured battery cell as defective when the value obtained by subtracting the second discrimination time (T2) is greater than the third threshold (the third threshold is a positive real number).

17. In any one of claims 11 to 16, The above reference profile includes a first differential profile regarding the differential value (dQ / dV or dV / dQ) of the voltage-capacity profile regarding the voltage and capacity of the reference battery cell, A battery cell activation system, wherein the measurement profile includes a second differential profile relating to a differential value (dQ / dV or dV / dQ) of a voltage-capacity profile relating to voltage and capacity of the measured battery cell.

18. In claim 17, The above-mentioned good / bad judgment unit (300) calculates the differential value corresponding to the first peak (P1) which is the main peak (P) or the first bottom which is the main bottom based on the first differential profile, and calculates the differential value corresponding to the second peak (P2) which is the main peak (P) and corresponds to the first peak (P1) or the second bottom which is the main bottom based on the second differential profile, and if the value obtained by subtracting the differential value (dQ / dV) corresponding to the first peak (P1) from the differential value (dQ / dV) corresponding to the second peak (P2) is greater than a fourth threshold value (the fourth threshold value is a positive real number) or if the value obtained by subtracting the differential value (dV / dQ) corresponding to the second bottom from the differential value (dV / dQ) corresponding to the first bottom is greater than a fifth threshold value (the fifth threshold value is a positive real number), the measured battery cell is considered defective. A battery cell activation system that predicts or determines.

19. In claim 17, The above-mentioned positive / negative judgment unit (300) obtains the first peak (P1) as the main peak (P) or the first bottom as the main bottom based on the first differential profile, determines the existence of the second peak (P2) corresponding to the first peak (P1) and the main peak (P) or the second bottom corresponding to the first bottom and the main bottom based on the second differential profile, or if the second peak (P2) or the second bottom exists, calculates the differential value corresponding to the second peak (P2) or the second bottom, and if the second peak (P2) or the second bottom does not exist or the differential value (dQ / dV) corresponding to the second peak (P2) is subtracted from the differential value (dQ / dV) corresponding to the first peak (P1), the differential value is greater than a sixth threshold value (the sixth threshold value is a positive real number) or the differential value corresponding to the second bottom is greater than a sixth threshold value. A battery cell activation system that predicts or determines the measured battery cell as defective when the value obtained by subtracting the differential value (dV / dQ) corresponding to the first bottom from the differential value (dV / dQ) is greater than a seventh threshold value (the seventh threshold value is a positive real number).

20. A battery cell activation method (S900) using the battery cell activation system (10) of claims 1 to 19, A pre-charging process (S910) in which the pre-charging unit (100) pre-charges the battery cell, which may be in a pre-impregnation state before the electrolyte injected inside is sufficiently impregnated; A profile acquisition process (S920) in which the profile acquisition unit (200) acquires the profile regarding the voltage or capacity of the battery cell based on information measured while the battery cell is being precharged by the precharge unit (100); The above-mentioned good-bad judgment unit (300) predicts or determines the good-bad of the battery cell based on the profile, and a good-bad judgment process (S930); An aging process (S940) in which the battery cell determined to be good in the above-mentioned good-bad judgment process (S930) is aged; and The charging / discharging unit (400) includes a first charging process (S950) for charging the battery cell determined to be good in the good / bad judgment process (S930). How to activate a battery cell.

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