Battery inspection methods and battery inspection systems

Abstract

A battery inspection method and a battery inspection system are provided. The battery inspection method includes the following. The battery of the inspection object is self-discharged until a predetermined time has passed since the start of self-discharge. The voltage, current, temperature and ambient temperature of the battery at a time point after the predetermined time have passed are detected. A previous process is implemented before the self-discharge of the battery. Previous process information indicating the implementation conditions of the previous process is obtained. By referring to a predetermined correspondence between the previous process information, the voltage, current and temperature of the battery at a time point after the predetermined time have passed, the ambient temperature and the current convergence value, the current convergence value is calculated based on the obtained previous process information, the detected voltage, current and temperature and the detected ambient temperature. Based on the calculated current convergence value, it is determined whether the battery has a short circuit failure.

Description

Technical Field

[0001] This disclosure relates to battery inspection methods and battery inspection systems. Background Art

[0002] A technique for checking for short circuit defects in batteries has been proposed. For example, in the battery inspection method disclosed in Japanese Patent Application Publication No. 2019-113450, a current flows in the direction of charging or discharging the battery, and the battery condition is determined based on the convergence of the flowing current. Summary of the Invention

[0003] Consider using the battery's self-discharge current to check for short-circuit defects. If the convergence value of the self-discharge current after a predetermined time is less than a reference value, the battery is considered normal; conversely, if the convergence value is greater than the reference value, the battery is considered to have a short-circuit defect.

[0004] Sometimes, during the above checks, the ambient temperature changes, and consequently, the battery temperature fluctuates. This can lead to variations in the self-discharge current, making proper checks impossible. For example, the self-discharge current may become difficult to control, increasing the check time.

[0005] This disclosure was made to solve the above-mentioned problems. One of the purposes of this disclosure is to provide a technique that can properly check for short circuit defects in a battery even in the presence of temperature variations.

[0006] The battery inspection method involved in the first technical solution of the present invention includes:

[0007] The battery of the object under inspection is allowed to self-discharge until a predetermined time has elapsed since the start of self-discharge.

[0008] The voltage, current, and temperature of the battery, as well as the ambient temperature, are detected at a time point after the predetermined time has elapsed.

[0009] The preceding process is performed before the self-discharge of the battery;

[0010] Obtain information about the preceding process that represents the conditions for implementing the preceding process;

[0011] By referring to the predetermined correspondence between the preceding process information, the battery voltage, current, and temperature at a predetermined time point after the predetermined time, the ambient temperature, and the current convergence value, the current convergence value is calculated based on the obtained preceding process information, the detected voltage, current, and temperature, and the detected ambient temperature; and

[0012] Based on the calculated current convergence value, it is determined whether the battery has experienced a short circuit.

[0013] In the battery inspection method involved in the first technical solution above, the pre-implementation process may also include:

[0014] Electrolyte is injected into the housing containing the electrodes; and

[0015] This allows the injected electrolyte to permeate into the electrode body.

[0016] In the battery inspection method of the first technical solution mentioned above, the information of the preceding process may also include at least one of the following: the material of the electrolyte, the amount of electrolyte injected, the injection time of injecting electrolyte into the battery, and the penetration time of the electrolyte into the electrode body.

[0017] In the battery inspection method involved in the first technical solution above, the pre-implementation process may also include: charging the battery after the electrolyte has penetrated into the electrode body.

[0018] In the battery inspection method of the first technical solution mentioned above, the preceding process information may also include at least one of the following: a first residence time from the time the electrolyte is allowed to penetrate until the battery is charged; the temperature of the battery during charging; the ambient temperature of the battery during charging; and the voltage of the battery at the end of charging.

[0019] In the battery inspection method involved in the first technical solution above, the pre-implementation process may also include: performing high-temperature aging of the battery after charging.

[0020] In the battery inspection method of the first technical solution mentioned above, the preceding process information may also include at least one of the following: the second residence time from charging the battery to implementing high-temperature aging, the implementation time of high-temperature aging, the temperature of the battery during high-temperature aging, and the ambient temperature of the battery during high-temperature aging.

[0021] In the battery inspection method involved in the first technical solution above, the pre-implementation process may also include: cooling the battery after the high-temperature aging process.

[0022] In the battery inspection method described in the first technical solution above, the information from the preceding process may also include at least one of the battery cooling time and the temperature of the battery after cooling.

[0023] In the battery inspection method involved in the first technical solution above, the battery may also include a positive electrode, a negative electrode, and a separator.

[0024] The preceding process information may also include at least one of the following: the materials of the positive and negative electrodes, the thickness of the positive and negative electrodes, the weight per unit area of ​​the positive and negative electrodes, the moisture content of the positive and negative electrodes, the capacitance ratio of the positive and negative electrodes, and the material of the separator.

[0025] The second technical solution of the present invention relates to a battery inspection system configured to inspect for short-circuit defects in batteries that have undergone a previous process according to previous process information. The battery inspection system includes:

[0026] A voltage sensor that detects the battery voltage;

[0027] A current sensor that detects the current flowing in a battery;

[0028] Battery temperature sensor, which detects the temperature of the battery;

[0029] An ambient temperature sensor that detects the ambient temperature;

[0030] A memory storing the preceding process information, the battery voltage, current, and temperature at a predetermined point in time after a predetermined time has elapsed since the start of self-discharge, the ambient temperature, and the predetermined correspondence between the current convergence value; and

[0031] The processor determines whether the battery has a short circuit.

[0032] Here, the processor is configured as follows:

[0033] Obtain the aforementioned previous process information;

[0034] The voltage, current, and temperature of the battery, as well as the ambient temperature, are obtained at a point in time after a predetermined time has elapsed since the start of the battery's self-discharge.

[0035] By referring to the aforementioned correspondence, the current convergence value is calculated based on the obtained previous process information, the detected voltage, current and temperature, and the detected ambient temperature.

[0036] Based on the calculated current convergence value, it is determined whether the battery has experienced a short circuit.

[0037] According to this disclosure, even in the presence of battery temperature variations, it is possible to properly check for battery short-circuit defects. Attached Figure Description

[0038] The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, wherein like reference numerals denote like elements, and wherein:

[0039] Figure 1 This is a configuration diagram of a battery inspection system according to an embodiment of this disclosure;

[0040] Figure 2 This is a perspective view showing an example of the structure of the cells included in a battery;

[0041] Figure 3It is a diagram used to illustrate the effect of changes in ambient temperature on the behavior of self-discharge current;

[0042] Figure 4 This is a flowchart illustrating the overall process of battery inspection.

[0043] Figure 5 It is a diagram used to illustrate information about the preceding process;

[0044] Figure 6 This is a conceptual diagram of convergence value mapping;

[0045] Figure 7 This is a flowchart representing the processing steps of the inspection and handling process. Detailed Implementation

[0046] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Furthermore, identical or equivalent parts in the drawings will be labeled with the same reference numerals and will not be described repeatedly.

[0047] [Implementation Method]

[0048] <System Overall Structure>

[0049] Figure 1 This is a configuration diagram of a battery inspection system according to an embodiment of the present disclosure. The battery inspection system 10 includes connection terminals Tp and Tn. The connection terminals Tp and Tn are configured to electrically connect to the battery 9 to be inspected. The battery 9 is typically a newly manufactured virgin battery. The battery inspection system 10 performs an inspection to determine whether the battery 9 has a short circuit.

[0050] Battery 9 is a battery pack comprising multiple units 91 to 9n connected in series. The number of units n is typically several dozen. In this embodiment, each unit 91 to 9n is a lithium-ion battery. However, the type of battery that can be inspected is not limited to lithium-ion rechargeable batteries. Alternatively, battery 9 may be a single unit instead of a battery pack.

[0051] The battery monitoring system 10 also includes a DC power supply 1, a voltage sensor 2, a current sensor 3, a battery temperature sensor 4, an ambient temperature sensor 5, an external resistor 6, a controller 7, and a display 8. The controller 7 includes a processor 71, a memory 72, and an input / output interface 73.

[0052] The DC power supply 1 is configured to charge and discharge the battery 9 according to control commands from the controller 7. The DC power supply 1 is, for example, an AC / DC converter. The DC power supply 1 converts AC power supplied from an external AC power source (e.g., commercial power supply) 20 into DC power. The DC power supply 1 can also boost / buck the voltage of the DC power according to control commands from the controller 7.

[0053] Voltage sensor 2 is electrically connected between connection terminal Tp and connection terminal Tn. That is, voltage sensor 2 is connected in parallel with battery 9. Voltage sensor 2 detects the voltage (voltage V) between the terminals of battery 9 and outputs its detection result to controller 7.

[0054] Current sensor 3 is electrically connected between DC power supply 1 and connection terminal Tn. That is, current sensor 3 is connected in series with battery 9. Current sensor 3 detects the current I flowing in battery 9 and outputs its detection result to controller 7.

[0055] Battery temperature sensor 4 detects the temperature of battery 9 (battery temperature TB) and outputs the detection result to controller 7.

[0056] The ambient temperature sensor 5 detects the temperature of the atmosphere surrounding the battery 9 (ambient temperature TA) and outputs the detection result to the controller 7.

[0057] External resistor 6 is electrically connected between DC power supply 1 and terminal Tp. The resistance value of external resistor 6 affects the self-discharge current. The smaller the resistance value of external resistor 6, the faster the self-discharge current converges. Therefore, the resistance value of external resistor 6 should be appropriately set according to the magnitude of the self-discharge current to be adjusted (or the convergence time of the self-discharge current).

[0058] The processor 71 is, for example, a Central Processing Unit (CPU). The processor 71 controls the charging and discharging of the battery 9 by controlling the DC power supply 1. Furthermore, the processor 71 determines whether the battery 9 has a short circuit based on the magnitude of the self-discharge current. More specifically, if the convergence value of the self-discharge current is less than a reference value, the processor 71 determines that the battery 9 is normal; conversely, if the convergence value is greater than the reference value, it determines that the battery 9 has a short circuit.

[0059] The memory 72 includes read-only memory (ROM) and random access memory (RAM). The memory 72 stores the program executed by the processor 71, and also stores the mapping used in determining if the battery 9 has a short circuit. The method for creating this mapping will be explained in detail later.

[0060] The input / output interface 73 is connected to the external controller 7 in a communicative manner. The input / output interface 73 receives "previous process information" from the external server 30. This previous process information indicates the implementation conditions of the preceding process, which occurs before the self-discharge process of the battery 9. This previous process information will be explained in detail later. Additionally, the input / output interface 73 outputs a determination result to the display 8 regarding whether the battery 9 has a short circuit.

[0061] <Unit Composition>

[0062] Figure 2 This is a perspective view showing an example of the configuration of the units included in battery 9. The configurations of units 91 to 9n are the same; therefore, the description will focus on the configuration of unit 91. Figure 2 The diagram shows a perspective view of the interior of cell 91. In this example, cell 91 is a sealed square battery. Cell 91 includes a battery casing 911, electrode bodies 912, and electrolyte 913.

[0063] The battery casing 911 is formed, for example, of an aluminum (Al) alloy. The battery casing 911 includes a casing body 911A and an upper surface component 911B. The casing body 911A houses the electrode body 912 and the electrolyte 913. The electrode body 912 is, for example, a wound type. That is, a laminate is formed by alternately stacking the positive and negative electrodes while sandwiching a separator (neither shown). Further, this laminate is wound into a cylindrical shape. The electrolyte 913 (the liquid level is indicated by a single-dotted line) is injected into the battery casing 911 and permeates into the electrode body 912. A positive terminal 914 and a negative terminal 915 are provided on the upper surface component 911B. A battery temperature sensor 4 is, for example, disposed between the positive terminal 914 and the negative terminal 915.

[0064] For the positive electrode active material layer, negative electrode active material layer, separator, and electrolyte 913, conventionally known materials can be used as the positive electrode active material, negative electrode active material, separator, and electrolyte of the lithium-ion battery. As an example, the positive electrode active material layer can be a ternary material (NCM) obtained by replacing a portion of lithium cobalt oxide with nickel and / or manganese. The negative electrode active material layer can be graphite. The separator can be a polyolefin (e.g., polyethylene or polypropylene). The electrolyte contains an organic solvent (a mixture of dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), and ethylene carbonate (EC), etc.), a lithium salt (LiPF6, etc.), and additives (lithium bis(oxalate)borate, LiBOB, or Li[PF2(C2O4)2], etc.).

[0065] <Temperature Variation>

[0066] For batteries under inspection, short-circuit defects are checked based on the convergence value of the battery's self-discharge current. If the convergence value of the self-discharge current is less than a reference value, the battery is considered normal. Conversely, if the convergence value is greater than the reference value, the battery is considered to have a short-circuit defect. Sometimes, during such inspections, changes in ambient temperature (e.g., air conditioning temperature) cause corresponding temperature fluctuations in the battery.

[0067] Figure 3 This graph illustrates the effect of changes in ambient temperature on the behavior of self-discharge current. The horizontal axis represents time, and the vertical axis represents the self-discharge current. Figure 3 In the diagram, the solid line represents the behavior of the self-discharge current when a temperature difference is generated between the ambient temperature TA and the battery temperature TB, and the dashed line represents the behavior of the self-discharge current when no temperature difference is generated.

[0068] Without a temperature difference, the self-discharge current typically converges within tens of minutes (approximately 30 minutes in this example). In contrast, with a temperature difference, the convergence of the self-discharge current may take hundreds of minutes (approximately 450 minutes in this example). Therefore, when a temperature difference occurs, the self-discharge current may have difficulty converging, increasing the inspection time. Alternatively, even with a fixed inspection time, the self-discharge current may not converge sufficiently, reducing inspection accuracy.

[0069] Therefore, in this embodiment, the following configuration is adopted: various parameters (descriptive variables) that may affect the convergence of the self-discharge current are determined, and the correspondence between these descriptive variables and the convergence value of the self-discharge current is pre-calculated and mapped. This mapping is called "convergence value mapping". In addition to the battery voltage V, current I, battery temperature TB, and ambient temperature TA at a predetermined time point after the self-discharge process, the convergence value mapping also includes the implementation conditions of the preceding process as descriptive variables. The descriptive variables representing the implementation conditions of the preceding process are called "previous process information". Hereinafter, based on a brief description of the overall process of the battery 9 inspection process, the preceding process information will be described in detail.

[0070] <Inspection process as a whole>

[0071] Figure 4 This is a flowchart illustrating the overall process of battery inspection. Hereinafter, each step will be abbreviated as S. Steps S1 to S6 correspond to the steps preceding the self-discharge process and are primarily performed by the inspection supervisor. Steps S7 and S8 are performed by the battery inspection system 10.

[0072] In S1, battery 9 is assembled (assembly process). More specifically, in the assembly process, electrode body 912 is fabricated from positive electrode, negative electrode, and separator (see reference). Figure 2 Additionally, the positive terminal 914, negative terminal 915, positive current collector terminal, and negative current collector terminal (not shown) are assembled onto the cover to fabricate the upper surface component 911B. Then, the electrode body 912 is welded to the upper surface component 911B. The welded electrode body 912 is housed within the housing body 911A. Then, laser welding is performed on the opening edge of the housing body 911A and the outer peripheral edge of the upper surface component 911B.

[0073] In S2, electrolyte 913 is injected into the battery housing 911 through the injection port (not shown) of the upper surface component 911B provided on the battery housing 911 for a predetermined time (injection time) (injection process). After the electrolyte is injected, the battery housing 911 is sealed by a sealing component (not shown).

[0074] In S3, the injected electrolyte 913 diffuses to the entire surface of the electrode body 912. Then, the electrolyte 913 on the surface of the electrode body 912 penetrates into the interior of the electrode body 912 over a certain period of time (penetration time) (penetration process).

[0075] In step S4, battery 9 is connected to a charger (not shown). Battery 9 is charged to a predetermined SOC (State of Charge) (charging process). In this embodiment, the battery temperature TB during charging, the ambient temperature TA during charging, and the voltage V of battery 9 at the end of charging can be measured. Additionally, battery 9 is held for a certain period until the process transitions from the permeation step to the charging step. This holding time can also be measured.

[0076] In step S5, the charged battery 9 is placed in a constant-temperature bath (not shown) that is maintained at a high temperature. High-temperature aging (high-temperature aging process) is performed in the constant-temperature bath for a predetermined time of approximately several hours (high-temperature aging time). In this embodiment, the battery temperature TB and / or the ambient temperature TA during the high-temperature aging process can be measured. Additionally, the residence time of the battery 9 from the charging process to the transition to the high-temperature aging process can also be measured.

[0077] In S6, the battery 9, after high-temperature aging, is placed at room temperature (typically 25°C) for a certain period of time (cooling time) to cool down (cooling process). In this embodiment, the battery temperature TB during the cooling process can be measured.

[0078] In S7, the cooled battery 9 is placed in the battery inspection system 10. The battery inspection system 10 measures the self-discharge current until a predetermined time has elapsed (self-discharge process). More specifically, the battery inspection system 10 first obtains the voltage of the battery 9 when there is no current flowing in the battery 9 from the voltage sensor 2, that is, the open circuit voltage (OCV) of the battery 9. Furthermore, the battery inspection system 10 sets the supply voltage of the DC power supply 1 to a value equal to the OCV of the battery 9. To accelerate the convergence of the self-discharge current, the supply voltage of the DC power supply 1 can also be set to a value higher than the OCV of the battery 9. Then, as time passes, the voltage V of the battery 9 decreases due to self-discharge. A voltage difference is then generated between the supply voltage from the DC power supply 1 and the voltage of the battery 9. A self-discharge current flows due to this voltage difference, and this current value is measured by the current sensor 3. Further, in this embodiment, in addition to the self-discharge current, the battery inspection system 10 also measures the voltage V, the battery temperature TB, and the ambient temperature TA at a point in time after the aforementioned predetermined time. In addition, it is also possible to measure the residence time of battery 9 from the cooling process to the self-discharge process.

[0079] In S8, the battery inspection system 10 compares the convergence value of the self-discharge current in S7 with the reference value to determine whether the battery 9 is in good condition (whether there is a short circuit) (inspection and processing). Furthermore, Figure 4 All of the preceding processes shown are not necessarily required, and some processes (any of the processes S4 to S6) can be omitted.

[0080] <Previous Process Information>

[0081] Figure 5 This is a diagram used to illustrate information about the preceding process. As information about the preceding process, it can be used... Figure 5 At least one of the specified variables shown. That is, you may use a single specified variable or a combination of two or more specified variables.

[0082] Variables associated with the assembly process include electrode (positive and negative) materials, electrode thickness, basis weight, water content, capacitance ratio of positive to negative electrodes, and separator material. Variables associated with the electrolyte injection process include electrolyte material, amount injected, and injection time. Variables associated with the permeation process include permeation time. Variables associated with the charging process include residence time from permeation to charging (first residence time), battery temperature TB during charging, ambient temperature TA during charging, and battery voltage V at the end of charging. Variables associated with the high-temperature aging process include residence time from charging to high-temperature aging (second residence time), high-temperature aging time, battery temperature TB during high-temperature aging, and ambient temperature TA during high-temperature aging. Variables associated with the cooling process include cooling time, residence time from cooling to self-discharge (third residence time), and battery temperature TB during cooling.

[0083] The electrode material, electrode thickness, etc., in the preceding process information (the variables described above) are known according to the specifications of battery 9. This known preceding process information is registered in advance on server 30. On the other hand, the dwell time from the permeation process to the charging process is measured by the inspection supervisor during the execution of the corresponding process. Furthermore, the measured preceding process information is collected by the inspection supervisor inputting it into a terminal (not shown) and then sent to server 30 (see reference 1). Figure 1 Therefore, the battery inspection system 10 can obtain the desired previous process information through communication with the server 30.

[0084] <Convergence Value Mapping>

[0085] Figure 6 This is a conceptual diagram of the convergence value mapping. As mentioned earlier, the convergence value mapping defines the correspondence between the battery voltage V, current I, battery temperature TB, ambient temperature TA, previous process information, and the convergence value of the self-discharge current at a predetermined time point after the self-discharge process. The following explains the method for creating the convergence value mapping.

[0086] A system (not shown) capable of measuring self-discharge current in the same manner as battery testing system 10 is installed in a thermostatic bath maintained at room temperature (25°C). A large number of batteries of the same type as battery 9 are prepared. The air conditioning temperature of the room where the batteries are placed can be varied to various values ​​within a temperature range including room temperature (e.g., 25°C ± a few°C).

[0087] By placing the battery for a certain period of time, the battery temperature TB approaches the air conditioning temperature. The self-discharge current of the battery at a temperature approximately equal to the air conditioning temperature is measured within the constant temperature bath. More specifically, at a predetermined time point (e.g., 100 minutes) after the start of self-discharge, longer than the time required for the self-discharge current to converge, the battery voltage V, current I (the convergence value of the self-discharge current), battery temperature TB, and ambient temperature TA (= the set temperature of the constant temperature bath) are measured. The convergence value of the self-discharge current can be obtained by averaging the variation in current I over a period smaller than a predetermined value. By setting different air conditioning temperatures for each battery, the convergence value of the self-discharge current under various temperature conditions can be measured. The obtained measurement results are managed in conjunction with information from previous processes.

[0088] Next, data cleaning is performed on the obtained measurement results. Specifically, outliers in the convergence value of the self-discharge current are removed, and the data balance between temperature conditions is adjusted.

[0089] Then, known regression methods are used to organize the data (the correspondence between the aforementioned measurement results, previous process information, and the convergence value of the self-discharge current at time points after a predetermined time in the self-discharge process). Data organization can also be performed using machine learning. When using machine learning, gradient boosted tree regression, rule-fit regression, random forest regression, etc., can be used. A convergence value map is then created. The created convergence value map is stored in the memory 72 of the controller 7 of the battery inspection system 10.

[0090] Furthermore, the convergence value mapping is equivalent to the "correspondence" involved in this disclosure. The "correspondence" involved in this disclosure is not limited to mapping, but can also be a data table, function, relation, etc.

[0091] <Inspection and Processing>

[0092] Figure 7 This is a flowchart illustrating the processing steps of the inspection process (step S8). This flowchart is executed when predetermined conditions are met (e.g., when the inspection supervisor instructs the process to begin). Each step is implemented by software based on the controller 7 (processor 71), but can also be implemented by hardware (circuit) configured within the controller 7.

[0093] As described above, the preceding process information is collected by the server 30. In S81, the controller 7 obtains the preceding process information related to the battery 9 of the object being inspected from the server 30.

[0094] In S82, the controller 7 obtains the voltage V, current I, battery temperature TB, and ambient temperature TA from the corresponding sensors after a predetermined time (the same length as the time used in the convergence value mapping, for example, 100 minutes) since the start of self-discharge.

[0095] In S83, the controller 7 refers to the convergence value mapping stored in the memory 72 and calculates the convergence value of the self-discharge current corresponding to the value obtained in S82.

[0096] In S84, the controller 7 determines whether the calculated convergence value is less than a predetermined reference value. If the convergence value is less than the reference value ("Yes" in S84), the controller 7 determines that the battery 9 under inspection is a qualified product (normal) (S85). On the other hand, if the convergence value is greater than or equal to the reference value ("No" in S84), the controller 7 determines that the battery 9 under inspection is a defective product (a short circuit has occurred) (S86). Then, the controller 7 displays the determination result on the display 8 (S87).

[0097] As described above, in this embodiment, a convergence value mapping is used to calculate the convergence value of the self-discharge current. The convergence value mapping includes, in addition to the voltage V, current I, battery temperature TB, and ambient temperature TA at a time point after a predetermined time has elapsed since the start of self-discharge, information from previous processes. According to the inventors' research, by including this information in the convergence value mapping, the behavior of the self-discharge current can be accurately predicted even when the ambient temperature (air conditioning temperature, etc.) changes. Therefore, according to this embodiment, even when there is a temperature change in the battery 9 being inspected, short-circuit defects in the battery 9 can be properly inspected. As a result, the inspection time can be shortened.

[0098] The embodiments disclosed herein should be considered illustrative in all respects, and not restrictive. The scope of this disclosure is defined not by the description of the embodiments above, but by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. A battery inspection method, comprising: The battery of the object under inspection is allowed to self-discharge until a predetermined time has elapsed since the start of self-discharge. The voltage, current, and temperature of the battery, as well as the ambient temperature, are detected at a time point after the predetermined time has elapsed. A pre-process is performed prior to the self-discharge of the battery. The pre-process includes: injecting electrolyte into a housing containing an electrode body; and allowing the injected electrolyte to permeate into the electrode body. Obtain preceding process information representing the implementation conditions of the preceding process, the preceding process information including the material of the electrolyte, the amount of electrolyte injected, the injection time of injecting the electrolyte into the battery, and the permeation time of allowing the electrolyte to permeate into the electrode body; By referring to the predetermined correspondence between the preceding process information, the battery voltage, current, and temperature at a predetermined time point after the predetermined time, the ambient temperature, and the current convergence value, the current convergence value is calculated based on the obtained preceding process information, the detected voltage, current, and temperature, and the detected ambient temperature; and Based on the calculated current convergence value, it is determined whether the battery has experienced a short circuit.

2. The battery inspection method according to claim 1, The preceding steps also include: The battery is charged after the electrolyte has permeated into the electrode body.

3. The battery inspection method according to claim 2, The preceding process information includes at least one of the following: a first residence time from the time the electrolyte permeates to the time the battery is charged; the temperature of the battery during charging; the ambient temperature during charging; and the voltage of the battery at the end of charging.

4. The battery inspection method according to claim 2 or 3, The preceding steps also include: The battery is subjected to high-temperature aging after it is charged.

5. The battery inspection method according to claim 4, The preceding process information includes at least one of the following: a second residence time from charging the battery to implementing the high-temperature aging, the implementation time of the high-temperature aging, the temperature of the battery during the high-temperature aging, and the ambient temperature during the high-temperature aging.

6. The battery inspection method according to claim 4, The preceding steps also include: The battery is cooled after the high-temperature aging process is carried out.

7. The battery inspection method according to claim 6, The preceding process information includes at least one of the battery's cooling time and the battery's temperature after cooling.

8. The battery inspection method according to claim 1 or 2, The battery includes a positive electrode, a negative electrode, and a separator. The preceding process information includes at least one of the following: the materials of the positive and negative electrodes, the thicknesses of the positive and negative electrodes, the weight per unit area of ​​the positive and negative electrodes, the moisture content of the positive and negative electrodes, the capacitance ratio of the positive and negative electrodes, and the material of the separator.

9. A battery inspection system configured to inspect for short-circuit defects in batteries that have undergone a previous process according to previous process information, the battery inspection system comprising: A voltage sensor that detects the voltage of the battery; A current sensor that detects the current flowing in the battery; A battery temperature sensor that detects the temperature of the battery; An ambient temperature sensor that detects the ambient temperature; The memory stores the preceding process information, the battery voltage, current and temperature at a predetermined time point after a predetermined time has elapsed since the start of self-discharge, the ambient temperature and the predetermined correspondence between the current convergence value. as well as The processor determines whether the battery has experienced a short circuit. The processor is configured as follows: Obtain the preceding process information, which includes the electrolyte material, the amount of electrolyte injected, the injection time of the electrolyte into the battery, and the permeation time of the electrolyte to permeate into the electrode body; The voltage, current, and temperature of the battery, as well as the ambient temperature, are obtained at a point in time after a predetermined time has elapsed since the start of the battery's self-discharge. By referring to the aforementioned correspondence, the current convergence value is calculated based on the obtained previous process information, the detected voltage, current and temperature, and the detected ambient temperature. Based on the calculated current convergence value, it is determined whether the battery has experienced a short circuit.

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