Battery inspection system and battery inspection method

Abstract

According to some embodiments, a battery inspection system comprises: a charging / discharging device configured to charge and discharge a target battery in a capacity measurement process; and a control device configured to calculate the battery capacity of the target battery on the basis of charging / discharging data in the capacity measurement process, calculate a first internal resistance of the target battery on the basis of the charging / discharging data in at least a part of a charging / discharging section of the capacity measurement process, and correct the first internal resistance to a second internal resistance on the basis of the difference between a first battery environment of the capacity measurement process and a second battery environment for battery shipment.

Description

Battery inspection system and battery inspection method

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority from Republic of Korea Patent Application No. 10-2024-0086062, filed July 1, 2024, the entire disclosure of which is incorporated herein by reference.

[0003] Technology field

[0004] The embodiments disclosed in this document relate to a battery testing system and a battery testing method.

[0005] Recently, active research and development has been conducted on secondary batteries. The term "secondary battery" refers to a rechargeable battery, encompassing both conventional Ni / Cd and Ni / MH batteries, as well as recent lithium-ion batteries. Among secondary batteries, lithium-ion batteries can boast higher energy densities than conventional Ni / Cd and Ni / MH batteries. They can be manufactured in small and lightweight designs, making them highly versatile power sources for mobile devices. Recently, their use has expanded to include power sources for electric vehicles, attracting attention as a next-generation energy storage medium.

[0006] A battery cell manufacturing process can be completed and shipped by charging it to the shipping SOC, followed by an end-of-line (EOL) process. Before the assembled cell enters the EOL process, its capacity and internal resistance can be tested. Because battery capacity testing requires discharging the cell to a fully discharged state, conventional testing techniques require partially charging the cell after capacity testing to the shipping SOC, followed by a separate charge-discharge operation to test the internal resistance. This conventional approach can be problematic in terms of inefficiency, such as increased charge-discharge cycles and complex transport paths.

[0007] An object of the embodiments disclosed in this document is to provide a battery testing system and a battery testing method that can eliminate inefficiency caused by additional charge / discharge operations for measuring internal resistance.

[0008] The technical objectives of the embodiments disclosed in this document are not limited to the technical tasks mentioned above, and other technical tasks not mentioned will be clearly understood by those skilled in the art from the descriptions below.

[0009] According to some embodiments, a battery inspection system includes a charge / discharge device configured to perform charge / discharge on a target battery in a capacity measurement process; and a control device configured to calculate a battery capacity of the target battery based on charge / discharge data in the capacity measurement process, calculate a first internal resistance of the target battery based on the charge / discharge data in at least some of the charge / discharge sections of the capacity measurement process, and correct the first internal resistance to a second internal resistance based on a difference between a first battery environment in the capacity measurement process and a second battery environment for battery shipment.

[0010] According to some embodiments, the charging / discharging device is configured to partially charge the target battery according to shipping conditions in a shipping charging process when the charging / discharging section of the capacity measurement process is terminated.

[0011] According to some embodiments, the battery inspection system further includes a transfer device configured to transfer the target battery from the shipping charging process to an end of line (EOL) process when partial charging of the target battery is completed in the shipping charging process, wherein the second battery environment represents an environment in which no internal resistance measurement process exists between the shipping charging process and the EOL process.

[0012] According to some embodiments, the charge / discharge section of the capacity measurement process includes a first section for discharging the target battery from a fully charged state to a fully discharged state, and the control device is configured to calculate the first internal resistance based on the charge / discharge data in at least a portion of a second section of the first section.

[0013] According to some embodiments, the start time of the first section coincides with the start time of the second section, and the control device is configured to calculate the first internal resistance based on a discharge current value in the first section set to measure the battery capacity in the capacity measurement process and an amount of voltage decrease of the target battery during the second section.

[0014] According to some embodiments, the difference between the first battery environment and the second battery environment includes a difference between a first SOC value corresponding to a full state of charge of the second section and a second SOC value corresponding to a partial state of charge for battery shipment, and the control device is configured to correct the first internal resistance to the second internal resistance based on the difference between the first SOC value and the second SOC value.

[0015] According to some embodiments, the difference between the first battery environment and the second battery environment includes a difference between a first battery temperature in the capacity measurement process and a second battery temperature in the shipment charging process, and the control device is configured to correct the first internal resistance to the second internal resistance based on the difference between the first battery temperature and the second battery temperature.

[0016] According to some embodiments, a battery inspection method includes: performing charging and discharging on a target battery in a capacity measurement process; calculating a battery capacity of the target battery based on charge and discharge data in the capacity measurement process; calculating a first internal resistance of the target battery based on the charge and discharge data in at least a portion of a charge and discharge section of the capacity measurement process; and correcting the first internal resistance to a second internal resistance based on a difference between a first battery environment in the capacity measurement process and a second battery environment for battery shipment.

[0017] According to some embodiments, the battery inspection method further includes a step of partially charging the target battery according to shipping conditions in a shipping charging process after the charge / discharge section of the capacity measurement process is completed.

[0018] According to some embodiments, the method further comprises the step of transferring the target battery from the shipping charging process to an end of line (EOL) process when partial charging of the target battery is completed in the shipping charging process, wherein the second battery environment represents an environment in which no internal resistance measurement process exists between the shipping charging process and the EOL process.

[0019] According to some embodiments, the charge / discharge section of the capacity measurement process includes a first section for discharging the target battery from a fully charged state to a fully discharged state, and the step of calculating the first internal resistance includes a step of calculating the first internal resistance based on the charge / discharge data in at least a portion of a second section of the first section.

[0020] According to some embodiments, the starting point of the first section coincides with the starting point of the second section, and the step of calculating the first internal resistance includes the step of calculating the first internal resistance based on a discharge current value in the first section set to measure the SOC value in the capacity measuring process and an amount of voltage decrease of the target battery during the second section.

[0021] According to some embodiments, the difference between the first battery environment and the second battery environment includes a difference between a first SOC value corresponding to a full state of charge of the second section and a second SOC value corresponding to a partial state of charge for battery shipment, and the step of correcting with the second internal resistance includes a step of correcting the first internal resistance with the second internal resistance based on the difference between the first SOC value and the second SOC value.

[0022] According to some embodiments, the difference between the first battery environment and the second battery environment includes a difference between a first battery temperature in the capacity measuring process and a second battery temperature in the shipping charging process, and the step of compensating with the second internal resistance includes a step of compensating the first internal resistance with the second internal resistance based on the difference between the first battery temperature and the second battery temperature.

[0023] According to the embodiments disclosed in this document, a battery testing system and a battery testing method can be provided that can eliminate inefficiency caused by additional charge / discharge operations for measuring internal resistance.

[0024] The technical effects according to the embodiments disclosed in this document are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art according to the disclosure of this document.

[0025] FIG. 1 illustrates a battery testing system for testing a target battery according to some embodiments.

[0026] FIG. 2 illustrates elements constituting a battery testing system according to some embodiments.

[0027] Figure 3 illustrates a conventional inspection method having a separate charge / discharge process for measuring internal resistance.

[0028] FIG. 4 illustrates how a battery testing system according to some embodiments measures internal resistance without a separate charge / discharge process.

[0029] Figures 5 and 6 illustrate a method for calculating internal resistance based on a voltage decrease measured in a second section of a capacity measurement process according to some embodiments.

[0030] FIG. 7 illustrates a method of compensating a first internal resistance with a second internal resistance based on a difference in a battery environment according to some embodiments.

[0031] FIG. 8 illustrates a method for compensating internal battery resistance based on the relationship between temperature and resistance according to some embodiments.

[0032] FIG. 9 illustrates a method for compensating battery internal resistance based on battery SOC difference according to some embodiments.

[0033] Figures 10 and 11 illustrate differences between a battery testing system according to some embodiments and a conventional testing method.

[0034] FIG. 12 illustrates steps of a battery testing method according to some embodiments.

[0035] Hereinafter, embodiments described in this document are described with reference to the attached drawings. However, this is not intended to limit the disclosure of this document to specific embodiments, and it should be understood that various modifications, equivalents, and / or alternatives of the embodiments described in this document are included.

[0036] The embodiments and terminology used in this document are not intended to limit the technical features described in this document to a specific embodiment, but should be understood to encompass various modifications, equivalents, or alternatives of the embodiment. In connection with the description of the drawings, similar reference numerals may be used to refer to similar or related components. The singular form of a noun corresponding to an item may include one or more of the item, unless the context clearly indicates otherwise.

[0037] In this document, the phrases "A or B", "at least one of A and B", "at least one of A or B", "A, B, or C", "at least one of A, B, and C", and "at least one of A, B, or C" can each include any one of the items listed together in that phrase, or all possible combinations thereof. Terms such as "first", "second", "first", "second", "A", "B", "(a)", or "(b)" may be used merely to distinguish the corresponding component from other corresponding components, and do not limit the corresponding components in any other respect (e.g., importance or order) unless specifically stated otherwise.

[0038] In this document, when a component (e.g., a first component) is referred to as being “connected,” “coupled,” or “connected,” with or without the terms “functionally” or “communicatively,” or “coupled” or “connected,” it means that the component can be connected to the other component directly (e.g., wired or wirelessly), or indirectly (e.g., via a third component).

[0039] The methods according to various embodiments disclosed in this document may be provided as a computer program product. The computer program product may be traded as a commodity between a seller and a buyer. The computer program product may be distributed in the form of a machine-readable storage medium (e.g., compact disc read-only memory, CD-ROM), or may be distributed online (e.g., downloaded or uploaded) through an application store or directly between two driver devices. In the case of online distribution, at least a portion of the computer program product may be temporarily stored or temporarily generated in a machine-readable storage medium, such as the memory of a manufacturer's server, an application store's server, or a relay server.

[0040] According to the embodiments disclosed in this document, each component (e.g., a module or a program) of the above-described components may include one or more entities, and some of the entities may be separated and placed in other components. According to the embodiments disclosed in this document, one or more components or operations of the aforementioned components may be omitted, or one or more other components or operations may be added. Alternatively or additionally, a plurality of components (e.g., a module or a program) may be integrated into a single component. In this case, the integrated component may perform one or more functions of each of the plurality of components identically or similarly to those performed by the corresponding component among the plurality of components prior to the integration. According to the embodiments disclosed in this document, the operations performed by a module, program, or other component may be executed sequentially, in parallel, iteratively, or heuristically, or one or more of the operations may be executed in a different order, omitted, or one or more other operations may be added.

[0041] FIG. 1 illustrates a battery testing system for testing a target battery according to some embodiments.

[0042] Referring to FIG. 1, a battery inspection system (120) can be configured to inspect a target battery (110).

[0043] The target battery (110) may include a battery cell manufactured through a battery manufacturing process. For example, the target battery (110) may be formed by completing a formation process, and the capacity and internal resistance of the target battery (110) may be inspected. Upon completion of the inspection of the target battery (110), the target battery (110) may be charged to the factory SOC, and an EOL process may be performed on the target battery (110).

[0044] The battery inspection system (120) inspects the capacity, internal resistance, etc. of the target battery (110), and when the inspection is completed, the target battery (110) can be transferred to another process, such as a shipping charging process or an EOL process. The battery inspection system (120) can perform charging and / or discharging on the target battery (110) during the process of inspecting the capacity, internal resistance, etc. If the inspection result shows that the capacity and / or internal resistance is defective, the battery inspection system (120) can retrieve the target battery (110) for re-inspection and / or disposal. If the capacity and / or internal resistance are normal, the target battery (110) can subsequently proceed to the shipping process.

[0045] FIG. 2 illustrates elements constituting a battery testing system according to some embodiments.

[0046] Referring to FIG. 2, the battery inspection system (120) may include a transport device (121), a control device (122), and a charging / discharging device (123). However, the present invention is not limited thereto, and some components may be omitted from the battery inspection system (120), or other general-purpose components may be further included in the battery inspection system (120).

[0047] The transport device (121) can transport the target battery (110) during the battery manufacturing process. For example, the transport device (121) can transport the target battery (110) for a formation process, a capacity measurement process, a shipping charging process, an EOL process, etc. The transport device (121) can include a transport means, such as a conveyor belt, for transporting the target battery (110).

[0048] The control device (122) can perform inspection operations of the target battery (110). For example, the control device (122) can inspect the capacity, internal resistance, etc. of the target battery (110). The control device (122) can control the operations of other components of the battery inspection system (120). For example, the control device (122) can control the operation of the transport device (121) and / or the operation of the charge / discharge device (123).

[0049] The control device (122) may include memory and / or a processor. The processor may be implemented in the form of at least one of a logic gate array, a microprocessor, a CPU, a GPU, and an AP. The memory may be implemented as a non-volatile device such as a ROM, a PROM, an EPROM, an EEPROM, a flash memory, a PRAM, an MRAM, an RRAM, an FRAM, or the like, or a volatile device such as a DRAM, an SRAM, an SDRAM, a PRAM, or the like, and may be implemented in the form of an HDD, an SSD, an SD, a Micro-SD, or the like, or a combination thereof.

[0050] The charging and discharging device (123) can perform charging and / or discharging of the target battery (110). For example, the charging and discharging device (123) can charge or discharge the target battery (110) while measuring the capacity and / or internal resistance of the target battery (110). For example, the charging and discharging device (123) can include a charging and discharging means such as a direct current power supply.

[0051] The charge / discharge device (123) may be configured to perform charging / discharging on the target battery (110) in the capacity measurement process. The control device (122) may be configured to calculate the battery capacity of the target battery (110) based on charge / discharge data of the target battery (110) resulting from the charge / discharge in the capacity measurement process. For example, the charge / discharge device (123) may charge the target battery (110) to a fully charged state and then discharge it to a fully discharged state in the capacity measurement process, and the battery capacity may be calculated based on the battery data during the process. For example, the battery capacity may be calculated based on the SOC value in the fully charged state and the SOC value in the fully discharged state.

[0052] The control device (122) may be configured to calculate the first internal resistance of the target battery (110) based on charge / discharge data in at least some sections of the charge / discharge section of the capacity measurement process. In a conventional battery inspection process, a process for inspecting the internal resistance exists separately from the capacity measurement process, but in the battery inspection system (120), both the capacity and internal resistance of the target battery (110) can be calculated in the capacity measurement process. The first internal resistance of the target battery (110) may be calculated based on data in some sections of the charge / discharge section of the capacity measurement process. For example, the first internal resistance may be calculated based on data in a discharge section of the charge / discharge section.

[0053] The control device (122) may be configured to correct the first internal resistance to the second internal resistance based on the difference between the first battery environment of the capacity measurement process and the second battery environment for battery shipment. The first battery environment of the capacity measurement process may be different from the battery shipment environment in terms of the temperature, SOC, etc. of the target battery (110). Since the inspection standard that the internal resistance value of the target battery (110) must satisfy is set based on the battery shipment environment, when the internal resistance value is measured based on the first battery environment of the capacity measurement process, it may be necessary to correct it.

[0054] The transport device (121) may be configured to transport the target battery (110) from the capacity measurement process to the shipping charging process, which partially charges the target battery (110), once the measurement of the battery capacity and the second internal resistance is completed. Unlike the conventional battery inspection process, where the internal resistance measurement is performed after the shipping charging, the battery inspection system (120) may perform the shipping charging process after both the capacity and the internal resistance are measured.

[0055] According to an embodiment, the charge / discharge device (123) may be configured to partially charge the target battery (110) according to the shipping conditions in the shipping charging process after the charging / discharging section of the capacity measurement process is completed. For example, the shipping conditions may include the shipping SOC conditions, and the shipping SOC conditions may be SOC 30% or less. The charge / discharge device (123) may partially charge the target battery (110) so that the SOC of the target battery (110) satisfies the shipping SOC conditions.

[0056] According to an embodiment, the transfer device (121) may be configured to transfer the target battery (110) from the shipment charging process to the EOL (end of line) process when partial charging of the target battery (110) is completed in the shipment charging process, and the second battery environment may represent an environment in which no internal resistance measurement process exists between the shipment charging process and the EOL process. Unlike a conventional battery inspection process in which a separate internal resistance measurement process exists before the EOL process is performed, in the battery inspection system (120), since the internal resistance is already measured before shipment charging is performed, the target battery (110) can be transferred directly to the EOL process when shipment charging is completed. This can reduce the number of operations of the charge / discharge device (123) and simplify the transfer path of the transfer device (121).

[0057] According to an embodiment, the charge / discharge section of the capacity measurement process may include a first section for discharging the target battery (110) from a fully charged state to a fully discharged state, and the control device (122) may be configured to calculate the first internal resistance based on charge / discharge data in at least a portion of a second section of the first section. For example, the first section may represent a discharge section during the capacity measurement process. The second section may be a section having a set duration, such as 10 seconds, and the numerical value of the duration may be changed in consideration of the calculation accuracy of the first internal resistance. Alternatively, the duration of the second section may be 5%, 10%, 15%, 20%, 25%, 30%, 50%, etc. of the duration of the first section.

[0058] According to an embodiment, the start time of the first section may coincide with the start time of the second section, and the control device (122) may be configured to calculate the first internal resistance based on a discharge current value in the first section set to measure the battery capacity in the capacity measurement process and an amount of voltage decrease of the target battery (110) during the second section. The first section and the second section may start simultaneously, and the second section may end before the first section. Since the second section is a discharge section, the SOC and voltage of the target battery (110) may decrease during the second section. The amount of voltage decrease in the second section may be a difference between the voltage at the start time and the voltage at the end time. Discharging in the first section may be performed by a constant current value. The charging / discharging device (123) may form a discharge current of a constant value in the target battery (110), thereby allowing discharging during the first section. The first internal resistance may be calculated based on the discharge current value and the amount of voltage decrease.

[0059] According to an embodiment, the difference between the first battery environment and the second battery environment may include a difference between a first SOC value corresponding to a full state of charge in the second section and a second SOC value corresponding to a partial state of charge for battery shipment, and the control device (122) may be configured to correct the first internal resistance to the second internal resistance based on the difference between the first SOC value and the second SOC value. If the SOC value in the battery cell changes, the value of the internal resistance may also change. Accordingly, even if the internal resistance test is passed in the capacity measurement environment, the internal resistance test may not be passed in the battery shipment environment. To correct such an error, the internal resistance value may be corrected based on the difference between the first SOC value and the second SOC value. For example, the correction may be performed using a table, profile, or the like that records a mapping relationship between the SOC and the internal resistance. For example, the environment for calculating the first internal resistance may be an SOC of about 95% or more and a voltage of about 4 V or more, while the battery shipment environment may be an SOC of about 30% to 80%, and the first internal resistance may be compensated for by the second internal resistance by taking into account this SOC difference.

[0060] According to an embodiment, the difference between the first battery environment and the second battery environment may include a difference between the first battery temperature in the capacity measurement process and the second battery temperature in the shipping charging process, and the control device (122) may be configured to correct the first internal resistance to the second internal resistance based on the difference between the first battery temperature and the second battery temperature. Similar to the SOC difference described above, the temperature difference may also cause fluctuations in the internal resistance value. In consideration of this, additional correction may be performed to check the internal resistance value based on the temperature in the battery shipping environment. For example, the battery temperature immediately before the shipping charging process is completed and transferred to the EOL process may be used as the inspection reference. In the battery inspection system (120), since both the capacity and the internal resistance can be measured in the capacity charging process and there is no separate internal resistance measurement process, the process of transferring the battery to the charging / discharging device (123) for internal resistance measurement via the transfer device (121) may be omitted, and the amount of battery temperature fluctuation during the transfer process may be reduced. Taking these differences into account, the difference between the first battery temperature and the second battery temperature can be calculated.

[0061] Figure 3 illustrates a conventional inspection method having a separate charge / discharge process for measuring internal resistance.

[0062] Referring to FIG. 3, a graph (300) may be illustrated illustrating a conventional inspection method having a separate charge / discharge process for measuring internal resistance. The horizontal and vertical axes of the graph (300) may represent time and voltage.

[0063] In graph (300), the formation process may be completed before the capacity measurement process begins. Battery charging may be performed at the beginning of the capacity measurement process, and battery discharging may be performed during the discharge period at the end of the capacity measurement process.

[0064] Once the discharge section is complete, the end-of-life charging process can begin. After charging to the shipment SOC through the shipment charging, a separate charge / discharge (310) can be performed to measure internal resistance. Additional transfer to a charge / discharge device may be required for the charge / discharge (310). Once the internal resistance measurement is completed through the charge / discharge (310), the end-of-life (EOL) process can begin.

[0065] In a conventional inspection method, capacity measurement and shipment charging can be performed in a first charger / discharger, and then internal resistance measurement can be performed in a second charger / discharger. Here, the first charger / discharger can be a general charger / discharger, and the second charger / discharger can be a large-capacity charger. Since temperature measurement is difficult in the second charger / discharger, the internal resistance can be calculated using the temperature at the time when shipment charging is completed in the first charger / discharger. Since the second charger / discharger is installed separately from the first charger / discharger, an error may occur in the calculation result of the internal resistance if the temperatures of the two are not the same, and the conventional inspection method did not consider correction of such an error.

[0066] FIG. 4 illustrates how a battery testing system according to some embodiments measures internal resistance without a separate charge / discharge process.

[0067] Referring to FIG. 4, a graph (400) may be illustrated illustrating a method in which a battery testing system (120) measures internal resistance without a separate charging / discharging process. The horizontal and vertical axes of the graph (400) may indicate time and voltage.

[0068] Unlike the graph (300) representing the prior art, the graph (400) may not perform separate charging and discharging for measuring internal resistance before and after the shipping charging process. Instead, the internal resistance may be measured based on the charging and discharging data measured in the initial portion (410) of the discharge section. The first internal resistance measured in the initial portion (410) may be compensated for as a second internal resistance to reflect the battery shipping environment. In this manner, the battery inspection system (120) can reduce the number of battery charging and discharging cycles and simplify the battery transport path compared to the conventional inspection method.

[0069] Figures 5 and 6 illustrate a method for calculating internal resistance based on a voltage decrease measured in a second section of a capacity measurement process according to some embodiments.

[0070] Referring to FIG. 5, a graph (500) may be illustrated showing an open circuit voltage (OCV) measured in a second section corresponding to the initial part of the discharge section of the capacity measurement process.

[0071] Graph (500) may represent cases where Cell #1 and Cell #2 are discharged at 60 A and 120 A at the beginning of the discharge section of the capacity measurement process. The beginning of the discharge section (second section) may refer to a period of 10 seconds from the start of the discharge section (first section). The value of 10 seconds may be set to a different value considering the inspection accuracy. In addition, the current values ​​of 60 A and 120 A may be changed to different values ​​depending on variations in the process design.

[0072] All four voltage measurements shown in the graph (500) may decrease during the second period. The internal resistances of cell #1 and cell #2 may be calculated based on the voltage decrease amount and the discharge current value (60 A, 120 A) during the second period. For example, the internal resistance may be a value obtained by dividing the voltage decrease amount by the discharge current value. The internal resistance calculated in this way may be the first internal resistance calculated in the environment of the capacity measurement process, and the first internal resistance may be corrected to the second internal resistance of the battery shipment environment.

[0073] Referring to FIG. 6, a table (600) representing charge / discharge data for the four voltage measurements shown in the graph (500) may be illustrated. The table (600) may represent a voltage decrease amount (dOCV), a discharge current value (Current, C-rate), and a first internal resistance (R). As illustrated, some differences may occur in the values ​​of the first internal resistance (R) for 60 A (0.6 C) and 120 A (1.2 C). However, it can be confirmed that the differences are not significant.

[0074] FIG. 7 illustrates a method of compensating a first internal resistance with a second internal resistance based on a difference in a battery environment according to some embodiments.

[0075] Referring to FIG. 7, a table (700) may be illustrated illustrating a method of compensating a first internal resistance to a second internal resistance based on differences in battery environments. The table (700) may compare a relatively high SOC in a capacity measurement process and a relatively low SOC in a battery shipment environment.

[0076] Since the capacity measurement process is performed in a range close to the fully charged state of the target battery (110), the first internal resistance can be calculated in a relatively high SOC range. On the other hand, the shipment of the finished battery product can be performed in a shipping SOC range of approximately 30% to 80%.

[0077] The difference in internal resistance due to such SOC difference can be confirmed in table (700). A table, profile, etc. that organizes the change in internal resistance due to the change in SOC can be constructed in advance, and the first internal resistance can be corrected to the second internal resistance using this. Meanwhile, in a similar manner to the SOC difference, a difference in battery temperature can also cause a difference in internal resistance, and the internal resistance can be additionally corrected based on the temperature difference between the capacity measurement environment and the battery shipment environment.

[0078] With reference to FIGS. 5 to 7, the graph (500) may represent the similarity of the initial 10-second resistance for a current of 120 A used in the internal resistance measurement section and a current of 60 A used in the capacity measurement section, based on the starting point (same SOC) of the shipment charging process. The current of 60 A in the capacity measurement section may be set to a different value depending on the design change of the development model. The table (600) may represent the resistance values ​​calculated for 120 A in the internal resistance measurement section and 60 A in the capacity measurement section, and the table (700) may compare the resistance values ​​measured for the same 120 A current in the internal resistance section by utilizing a portion of the starting point of the capacity measurement (upper SOC).

[0079] In summary, it can be confirmed that the resistance values ​​measured at different current values ​​at the same SOC are at similar levels (ΔV also increases as the current increases), the deviation of the resistance value according to the current size is small for battery cells above a certain capacity (e.g., 50 Ah), and the resistance value at a different time point (different SOC) can be determined by correcting the resistance value based on the discharge start time for capacity inspection.

[0080] FIG. 8 illustrates a method for compensating internal battery resistance based on the relationship between temperature and resistance according to some embodiments.

[0081] Referring to FIG. 8, a graph (800) illustrating a method for compensating internal battery resistance based on the relationship between temperature and resistance may be illustrated. The horizontal axis of the graph (800) may represent the battery temperature at the point where discharge in the capacity measurement process begins, and the vertical axis may represent the internal battery resistance calculated based on the discharge current value and the amount of voltage decrease.

[0082] As shown in trend line (810), the higher the discharge start temperature, the lower the internal resistance. Since the discharge start temperature may vary for each battery, it may be necessary to compensate for the effect of temperature to compare internal resistance based on the same temperature. For example, the reference temperature for internal resistance testing during the quality assurance (QA) stage may be 25°C, and the internal resistance values ​​at different discharge start temperatures may be compensated for the internal resistance value at 25°C.

[0083] Formula 1: R revised = {R discharge + α*(25℃ - T)}*β

[0084] As in Equation 1, the internal resistance R before compensation is calculated based on the temperature at the start of discharge by multiplying the temperature correction factor α by the difference between 25℃ and the battery temperature T. discharge The temperature effect can be compensated for. For example, the temperature correction coefficient α can be linked to the slope of the trend line (810). After compensating for the temperature effect, the SOC correction coefficient β can be additionally applied to obtain the internal resistance R after compensation. revised can be calculated. α and β can be constants and can be determined experimentally.

[0085] FIG. 9 illustrates a method for compensating battery internal resistance based on battery SOC difference according to some embodiments.

[0086] Referring to FIG. 9, a graph (900) illustrating a method of compensating internal battery resistance based on a difference in battery SOC may be illustrated. The horizontal axis of the graph (900) may represent internal resistance measured during a quality assurance (QA) stage, and the vertical axis may represent internal resistance measured during a capacity measurement process, divided into before and after SOC compensation.

[0087] Once battery manufacturing is complete, a quality assurance (QA) step may be performed on a sample of the completed batteries. During the QA step, various parameters, including internal resistance, may be inspected. The battery inspection system (120) may calculate the internal resistance based on the discharge current value and voltage decrease in the initial portion (410) of the discharge section of the capacity measurement process, and may correct this value to be identical to the internal resistance measured during the QA step.

[0088] Since the temperature and SOC of the battery may be different in the early part (410) of the discharge section of the capacity measurement process and the QA step, temperature correction and SOC correction may be performed. In the case of a temperature difference, the internal resistance measured at a temperature other than 25°C may be corrected to a value corresponding to 25°C. In the case of a SOC difference, in the early part (410) of the discharge section of the capacity measurement process, the SOC may be close to 100% due to full charge, whereas in the QA step, the SOC may be a value according to the shipping conditions (e.g., less than 30%). As shown in the table (700) of FIG. 7, since the internal resistance at 100% is different from the internal resistance at less than 30%, correction for this may be necessary.

[0089] The internal resistance values ​​before SOC correction in the graph (900) may be values ​​before the SOC correction coefficient β is applied after the temperature correction is applied in Equation 1. On the other hand, the internal resistance values ​​after SOC correction in the graph (900) may represent values ​​after the SOC correction coefficient β is applied.

[0090] In the graph (900), the distribution of internal resistance values ​​before SOC correction and the y = x graph have differences, whereas the distribution of internal resistance values ​​after SOC correction may become closer to the y = x graph. That is, before SOC correction, the internal resistance estimated in the capacity measurement process may be different from the internal resistance precisely inspected in the QA step, but after SOC correction, the internal resistance estimated in the capacity measurement process may be identical to or similar to the internal resistance precisely inspected in the QA step.

[0091] Figures 10 and 11 illustrate differences between a battery testing system according to some embodiments and a conventional testing method.

[0092] Referring to FIG. 10, a graph (1000) may be illustrated showing the performance differences between improved technology and conventional technology according to a battery inspection system. The conventional technology of the graph (1000) may correspond to the conventional technology discussed in FIG. 3.

[0093] In the graph (1000), the prior art may follow the first trend line (1010), and the improved technology may follow the second trend line (1020). Since the prior art separates the capacity measurement and the internal resistance measurement, the deviation of the internal resistance values ​​may be relatively large due to temperature deviation during the transport process, etc. In addition, since the first trend line (1010) of the prior art deviates from the y = x graph (1030), it can be confirmed that the internal resistance estimation values ​​according to the prior art are somewhat different from the internal resistance that is precisely inspected in the QA stage. On the other hand, since the second trend line (1020) according to the improved technology performs temperature compensation and SOC compensation, even if the internal resistance is measured together in the capacity measurement process without a separate process, the internal resistance estimation values ​​may be the same as or similar to the internal resistance that is precisely inspected in the QA stage.

[0094] Referring to FIG. 11, a table (1100) illustrating the differences between the battery testing system and conventional testing methods may be illustrated.

[0095] In the QA stage, the average of the internal resistance may be 1.251 Ω, and the standard deviation may be 0.018. In the case of the prior art discussed in FIG. 3, there is no difference in SOC compared to the QA stage, but since a temperature difference may occur, the average may be 1.215 Ω, which may be significantly different from 1.251 Ω in the QA stage. This difference in average may appear as a difference between the first trend line (1010) and the y = x graph (1030) in the graph (1000).

[0096] On the other hand, the improvement technology according to the battery inspection system (120) may have temperature differences and SOC differences because the internal resistance is measured in the early part (410) of the discharge section of the capacity measurement process as shown in FIG. 4. However, since corrections for the temperature difference and the SOC difference are performed, the average of the internal resistance may be the same as the average in the QA stage as illustrated in FIG. 8.

[0097] In addition, in the conventional technology, the temperature deviation may increase due to the transport time, etc., in the process of performing separate charging and discharging (310) for measuring internal resistance, but in the case of the improved technology, since the battery inspection system (120) performs internal resistance measurement simultaneously with capacity measurement, additional transport may be unnecessary, the temperature deviation may be reduced, and thus the standard deviation of internal resistance values ​​may be reduced.

[0098] FIG. 12 illustrates steps of a battery testing method according to some embodiments.

[0099] Referring to FIG. 12, the battery inspection method (1200) may include steps (1210) to (1240). However, the present invention is not limited thereto, and some steps may be omitted or other general steps may be added, and the steps of the battery inspection method (1200) may be executed in a different order than the illustrated order.

[0100] The battery inspection method (1200) may be composed of steps that are processed in a time-series manner in the battery inspection system (120). Therefore, even if the details are omitted below, the details described above for the battery inspection system (120) may be equally applied to the battery inspection method (1200).

[0101] Steps (1210) to (1240) of the battery inspection method (1200) can be performed by the transport device (121), the control device (122), and the charging / discharging device (123) of the battery inspection system (120).

[0102] In step (1210), the battery inspection system (120) can perform a step of performing charging and discharging on the target battery in the capacity measurement process.

[0103] In step (1220), the battery inspection system (120) can perform a step of calculating the battery capacity of the target battery based on charge / discharge data in the capacity measurement process.

[0104] In step (1230), the battery inspection system (120) may perform a step of calculating a first internal resistance of the target battery based on charge / discharge data in at least some of the charge / discharge sections of the capacity measurement process.

[0105] In step (1240), the battery inspection system (120) can perform a step of correcting the first internal resistance to the second internal resistance based on the difference between the first battery environment of the capacity measurement process and the second battery environment for battery shipment.

[0106] According to an embodiment, the battery inspection method (1200) may be implemented in the form of a computer program stored on a computer-readable storage medium. That is, the computer program may include instructions for implementing the battery inspection method (1200), and the program instructions may be stored on the computer-readable storage medium. The computer program may include a mobile application.

[0107] According to an embodiment, the computer-readable storage medium may include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical media such as CD-ROMs, DVDs, magneto-optical media such as floptical disks, and hardware devices specially configured to store and execute computer program instructions such as ROMs, RAMs, flash memories, and the like. The computer program instructions may include machine language codes generated by a compiler and high-level language codes that can be executed by a computer using an interpreter, etc.

[0108] The terms "include," "comprise," or "have" used herein, unless otherwise specifically stated, imply that the corresponding component may be included, and therefore should be interpreted to include other components rather than to exclude other components. All terms, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which the embodiments disclosed in this document pertain, unless otherwise defined. Commonly used terms, such as terms defined in dictionaries, should be interpreted to be consistent with their contextual meaning in the relevant art, and shall not be interpreted in an idealized or overly formal sense, unless explicitly defined in this document.

[0109] The above description is merely an illustrative description of the technical idea disclosed in this document, and those skilled in the art to which the embodiments disclosed in this document pertain may make various modifications and variations without departing from the essential characteristics of the embodiments disclosed in this document. Therefore, the embodiments disclosed in this document are not intended to limit the technical idea of ​​the embodiments disclosed in this document, but to explain it, and the scope of the technical idea disclosed in this document is not limited by these embodiments. The protection scope of the technical idea disclosed in this document should be interpreted by the claims below, and all technical ideas within a scope equivalent thereto should be interpreted as being included in the scope of rights of this document.

[0110] [Explanation of symbols]

[0111] 110: Target Battery 120: Battery Inspection System

[0112] 121: Transport device 122: Control device

[0113] 123: Charging and discharging device

Claims

1. A charging / discharging device configured to perform charging / discharging on a target battery in a capacity measurement process; and Calculate the battery capacity of the target battery based on the charge / discharge data in the above capacity measurement process, Calculating the first internal resistance of the target battery based on the charge / discharge data in at least some of the charge / discharge sections of the capacity measurement process, A battery inspection system comprising a control device configured to correct the first internal resistance to a second internal resistance based on a difference between a first battery environment of the capacity measurement process and a second battery environment for battery shipment.

2. In paragraph 1, A battery inspection system, wherein the charging / discharging device is configured to partially charge the target battery according to shipping conditions in a shipping charging process when the charging / discharging section of the capacity measurement process is completed.

3. In paragraph 2, Further comprising a transport device configured to transport the target battery from the shipping charging process to an EOL (end of line) process when partial charging of the target battery is completed in the shipping charging process; A battery inspection system, wherein the second battery environment represents an environment in which no internal resistance measurement process exists between the shipping charging process and the EOL process.

4. In paragraph 3, The charge / discharge section of the above capacity measurement process includes a first section for discharging the target battery from a fully charged state to a fully discharged state, A battery testing system, wherein the control device is configured to calculate the first internal resistance based on the charge / discharge data in at least a portion of the second section among the first sections.

5. In paragraph 4, The starting point of the first section above coincides with the starting point of the second section above, A battery inspection system, wherein the control device is configured to calculate the first internal resistance based on a discharge current value in the first section set to measure the battery capacity in the capacity measurement process and an amount of voltage decrease of the target battery during the second section.

6. In paragraph 5, The difference between the first battery environment and the second battery environment includes the difference between the first SOC value corresponding to the full charge state of the second section and the second SOC value corresponding to the partial charge state for battery shipment, A battery testing system, wherein the control device is configured to correct the first internal resistance to the second internal resistance based on a difference between the first SOC value and the second SOC value.

7. In paragraph 6, The difference between the first battery environment and the second battery environment includes the difference between the first battery temperature in the capacity measurement process and the second battery temperature in the shipment charging process, A battery testing system, wherein the control device is configured to correct the first internal resistance to the second internal resistance based on a difference between the first battery temperature and the second battery temperature.

8. A step of performing charging and discharging on a target battery in a capacity measurement process; A step of calculating the battery capacity of the target battery based on the charge / discharge data in the capacity measurement process; A step of calculating the first internal resistance of the target battery based on the charge / discharge data in at least some of the charge / discharge sections of the capacity measurement process; and A battery inspection method, comprising a step of correcting the first internal resistance to a second internal resistance based on a difference between a first battery environment of the capacity measurement process and a second battery environment for battery shipment.

9. In paragraph 8, A battery inspection method further comprising a step of partially charging the target battery according to shipping conditions in a shipping charging process after the charging and discharging section of the capacity measurement process is completed.

10. In paragraph 9, In the above shipping charging process, when partial charging of the target battery is completed, the step of transferring the target battery from the shipping charging process to the EOL (end of line) process is further included. A battery inspection method, wherein the second battery environment represents an environment in which no internal resistance measurement process exists between the shipping charging process and the EOL process.

11. In paragraph 10, The charge / discharge section of the above capacity measurement process includes a first section for discharging the target battery from a fully charged state to a fully discharged state, A battery inspection method, wherein the step of calculating the first internal resistance includes the step of calculating the first internal resistance based on the charge / discharge data in at least a part of the second section among the first sections.

12. In paragraph 11, The starting point of the first section above coincides with the starting point of the second section above, A battery inspection method, wherein the step of calculating the first internal resistance includes the step of calculating the first internal resistance based on a discharge current value in the first section set to measure the SOC value in the capacity measurement process and an amount of voltage decrease of the target battery during the second section.

13. In paragraph 12, The difference between the first battery environment and the second battery environment includes the difference between the first SOC value corresponding to the full charge state of the second section and the second SOC value corresponding to the partial charge state for battery shipment, A battery inspection method, wherein the step of compensating with the second internal resistance includes a step of compensating the first internal resistance with the second internal resistance based on a difference between the first SOC value and the second SOC value.

14. In paragraph 13, The difference between the first battery environment and the second battery environment includes the difference between the first battery temperature in the capacity measurement process and the second battery temperature in the shipment charging process, A battery inspection method, wherein the step of compensating with the second internal resistance includes a step of compensating the first internal resistance with the second internal resistance based on a difference between the first battery temperature and the second battery temperature.

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