JP6031875B2 - Method and apparatus for inspecting assembled battery - Google Patents

Description

  The present invention relates to an inspection method in a manufacturing process of an assembled battery composed of a plurality of battery cells connected in series, and an apparatus using the inspection method.

  In the assembled battery manufacturing process, the performance (quality) of the entire assembled battery is inspected, and only assembled batteries satisfying a certain quality standard are shipped as products. One of the indexes for examining the performance of the assembled battery is the battery capacity of the assembled battery. Conventionally, in order to measure the battery capacity of an assembled battery, once the assembled battery is fully charged, it is discharged until it is in an empty charge state, and the battery capacity is measured based on the amount of current discharged during this period, On the other hand, a method has been adopted in which the battery pack is once charged in an empty state and then charged until it is fully charged, and the battery capacity is measured based on the amount of current charged during this time.

  Patent Document 1 listed below describes a method and apparatus that can estimate the remaining capacity (SOC) of a secondary battery in a highly accurate and short time.

JP 2005-106747 A

  However, as in the prior art described above, in the method of discharging (or charging) until the assembled battery is once fully charged (or fully charged) and then fully charged (or fully charged), measurement is performed. There is a problem that a lot of time is required. In the manufacturing process of the assembled battery, it is necessary to perform various processes after the performance inspection, and it is desirable to perform the inspection in as short a time as possible.

  In addition, the technique of Patent Document 1 described above is only used to estimate the remaining capacity of the assembled battery, and cannot be used for inspection of the assembled battery.

  The present invention has been made in view of the above-described problems of the prior art, and an object thereof is to provide an assembled battery inspection method and inspection apparatus capable of inspecting the battery capacity of the assembled battery in a short time. To do.

In order to solve the above-described problems and achieve the object, an assembled battery inspection method according to the invention of claim 1 is an assembled battery inspection method including a plurality of battery cells connected in series. A battery charge / discharge step, an average cell voltage measurement step of measuring the voltage of the assembled battery in the middle of the charge / discharge step, and obtaining an average cell voltage value obtained by dividing the measured voltage value by the number of cells, and the average cell voltage A battery capacity estimation step of estimating a full charge capacity of the assembled battery from a value and a battery capacity characteristic curve corresponding to the type of the battery cell, and determining pass / fail according to the full charge capacity estimated in the battery capacity estimation step A capacity determination step.
According to the assembled battery inspection method of the second aspect of the present invention, there is provided a voltage variation measuring step of measuring a voltage variation of each battery cell of the assembled battery determined to be acceptable in the capacity determining step, and the value of the voltage variation is a predetermined value. And a voltage variation determination step of determining pass / fail according to whether or not it is below the determination line, wherein the predetermined determination line is determined based on the battery capacity characteristic curve.
In the assembled battery inspection method according to a third aspect of the invention, the predetermined determination line is changed according to a temperature environment in which the inspection is performed.
An inspection apparatus for an assembled battery according to a fourth aspect of the invention is an inspection apparatus for an assembled battery including a plurality of battery cells connected in series, and charging / discharging means for the assembled battery and charging / discharging by the charging / discharging means. Average cell voltage measuring means for measuring the voltage of the assembled battery in the middle of discharge and obtaining an average cell voltage value obtained by dividing the measured voltage value by the number of cells, and a battery capacity characteristic curve corresponding to the type of the battery cell are stored. Storage means, battery capacity estimation means for estimating a full charge capacity of the assembled battery from the average cell voltage value and the battery capacity characteristic curve stored in the storage means, and full charge estimated by the battery capacity estimation means Capacity determination means for determining pass / fail according to the capacity.
An inspection apparatus for an assembled battery according to the invention of claim 5 is a voltage variation measuring means for measuring a voltage variation of each battery cell of the assembled battery that has been determined to pass the capacity determining means, and the voltage variation is a predetermined determination line. And a voltage variation determining means for determining that it is acceptable when the following is true, wherein the predetermined determination line is defined based on the battery capacity characteristic curve.
The assembled battery inspection apparatus according to claim 6 is characterized in that the predetermined determination line is changed according to a temperature environment in which the inspection is performed.

According to the first and fourth aspects of the present invention, the full charge capacity of the assembled battery is estimated from the average cell voltage value of the battery cells constituting the assembled battery and the battery capacity characteristic curve corresponding to the type of the battery cell. Judge the pass / fail. Thereby, compared with the conventional performance inspection method which charges / discharges an assembled battery until it will be in a full charge state or an empty charge state, the performance inspection of an assembled battery can be performed in a short time.
According to the inventions of claim 2 and claim 5, when the full charge capacity of the assembled battery is acceptable (greater than or equal to a predetermined capacity) and the voltage variation of each battery cell is equal to or smaller than a predetermined determination line, it is determined as acceptable. . As described above, by performing the voltage variation inspection together with the estimation of the full charge capacity, the reliability of the inspection can be improved even in a short time measurement.
According to the third and sixth aspects of the invention, the inspection determination line is changed according to the temperature of the environment in which the inspection is performed. It is known that the charge / discharge characteristics of a battery change depending on the temperature, and the reliability of inspection can be further improved by making such a change (correction) depending on the temperature.

It is a block diagram which shows the structure of the assembled battery test | inspection apparatus 10 concerning embodiment. It is a graph which shows an example of a battery capacity characteristic curve. It is explanatory drawing which shows an example of the determination line of voltage variation. It is explanatory drawing for demonstrating the change of the determination line by temperature. 4 is a flowchart showing an inspection processing procedure of the inspection apparatus 10.

  Exemplary embodiments of an assembled battery inspection apparatus and inspection method according to the present invention will be described below in detail with reference to the accompanying drawings.

(Embodiment)
FIG. 1 is a block diagram illustrating a configuration of an assembled battery inspection device 10 according to an embodiment. The inspection apparatus 10 according to the embodiment inspects whether or not the battery capacity of the assembled battery 20 including a plurality of battery cells 202 connected in series is equal to or greater than a predetermined reference capacity (capacity performance inspection). In the manufacturing process of the assembled battery 20, the inspection device 10 is used when testing whether or not a certain quality standard is satisfied before shipment after a plurality of battery cells 202 are connected in series and packaged, for example.

  In the inspection apparatus 10, a general capacity performance inspection method (a method of discharging (or charging) a battery pack from a fully charged state (or a fully charged state) to a fully charged state (or fully charged state)) Compared with, inspection can be performed in a short time. Hereinafter, the capacity performance inspection performed by the inspection apparatus 10 is referred to as “time reduction inspection”, and the capacity performance inspection performed by a general method is referred to as “normal inspection”.

  In the present embodiment, the plurality of battery cells 202 used in the assembled battery 20 are all of the same type (model number and the like are the same) and have uniform battery performance. In the present embodiment, it is assumed that the specification capacity of the battery cell 202 is 50 Ah.

  In the inspection apparatus 10, a voltmeter 102 is connected to each battery cell 202 of the assembled battery 20. The voltmeter 102 is connected in parallel to the positive electrode side output terminal and the negative electrode side output terminal of the battery cell 202, and detects the battery voltage of the battery cell 202. The battery voltage of the battery cell 202 detected by the voltmeter 102 is output to the processing unit 120 described later.

  The switch circuit 108 and the current limiting circuit 106 are connected in series, and the series circuit of the switch circuit 108 and the current limiting circuit 106 is connected in series to the charging power source 104. Then, the positive output terminal of the charging power source 104 is connected to the positive output terminal of the battery pack 20 composed of a plurality of battery cells 202 via a series circuit of the switch circuit 108 and the current limiting circuit 106. The negative output terminal of the charging power source 104 is connected to the negative output terminal of the assembled battery 20. The series circuit of the switch circuit 108 and the current limiting circuit 106 constitutes a charging circuit that charges the assembled battery 20 with the charging power source 104.

  On the other hand, the switch circuit 112 and the load resistance circuit 110 are connected in series to constitute a discharge circuit of the assembled battery 20. The other terminal of the switch circuit 112 not connected to the load resistance circuit 110 is connected to the positive output terminal of the assembled battery 20, and the other terminal of the load resistance circuit 110 not connected to the switch circuit 112 is the assembled battery. 20 negative output terminals are connected.

  The switch circuits 108 and 112 are configured by normally open contacts that are closed based on a control signal output from the processing unit 120. Further, the current limiting circuit 106 and the load resistance circuit 110 are configured by a variable resistance circuit whose resistance value is variable based on a control signal output from the processing unit 120.

  The processing unit 120 includes a CPU, a ROM that stores and stores a control program, a RAM as an operation area of the control program, an EEPROM that holds various data in a rewritable manner, an interface unit that interfaces with peripheral circuits, and the like. Composed. When the CPU executes the control program, the processing unit 120 includes a storage unit 122, a charge / discharge unit 124, an average cell voltage measurement unit 126, a battery capacity estimation unit 128, a capacity determination unit 130, a voltage variation measurement unit 132, A voltage variation determination unit 134 is realized.

  The storage unit 122 stores a battery capacity characteristic curve corresponding to the type of the battery cell 202 constituting the assembled battery 20. The battery capacity characteristic curve is a voltage-battery capacity curve indicating a standard relationship between battery capacity and voltage in the battery cell 202 of the type. FIG. 2 is a graph showing an example of a battery capacity characteristic curve. In FIG. 2, the vertical axis represents the battery voltage (index value), and the horizontal axis represents the remaining capacity (SOC). As shown in FIG. 2, the battery voltage of the battery cell 202 and the SOC are correlated, and the battery voltage increases as the remaining capacity increases. The battery capacity characteristic curve recorded in the storage unit 122 is a standard battery capacity characteristic curve (satisfying specification performance) in the battery cell 202 used in the assembled battery 20 to be inspected in the inspection apparatus 10.

  As an example of how to obtain the battery capacity characteristic curve, for example, when the complete discharge and the full charge in the assembled battery state are repeated, the change in the voltage value of each battery cell 202 is measured. A battery capacity characteristic curve as shown in FIG. 2 is obtained by continuously recording the change in the voltage value. The battery capacity characteristic curve recorded in the storage unit 122 may be measured in advance by the above-described method using a standard battery cell 202 in the inspection apparatus 10, for example. Data (battery capacity characteristic curve) provided by a person may be used.

  The charging / discharging unit 124 controls the charging circuit configured by the switch circuit 108, the current limiting circuit 106, and the charging power source 104, or the discharging circuit configured by the switching circuit 112 and the load resistance circuit 110, so that the assembled battery 20 Charge or discharge (charge / discharge).

  The average cell voltage measuring unit 126 measures the voltage of the assembled battery 20 during charging / discharging by the charging / discharging unit 124, and obtains an average cell voltage value obtained by dividing the measured voltage value by the number of cells. The average cell voltage measuring means 126 charges or discharges the battery pack 20 with a first predetermined amount of current smaller than the full capacity of the battery pack 20, for example, and calculates the average voltage of the battery cell 202 before and after the charge or discharge. Measure changes. In the present embodiment, the average value may be any of arithmetic average, median value, and mode value.

  The amount of current (first predetermined amount) to be charged or discharged in the average cell voltage measuring means 126 is made smaller than the full capacity of the assembled battery 20. This is because if the first predetermined amount is the full capacity of the assembled battery 20, it takes a time equivalent to the normal inspection. The method for determining the first predetermined amount is arbitrary, but it is sufficient that the change in the average voltage of the battery cell 202 before and after charging or discharging can be identified, for example.

  Specifically, the specified capacity of the battery cell 202 is 50 Ah as described above. For example, when the battery cell 202 is discharged by 5 Ah, the SOC can be reduced by 10%. For example, if the average voltage of the battery cell 202 at the time of inspection is 2.75, it can be estimated that the SOC of the battery cell 202 is 50%. When 5 Ah is discharged from this state, the SOC of the battery cell 202 is 40%, and the voltage is estimated to be approximately 2.70 (−0.05).

  If the measurement accuracy of the voltmeter 102 can identify this voltage change (−0.05), the first predetermined amount can be set to 5 Ah. As shown in FIG. 2, since the battery capacity characteristic curve is not uniform, for example, from the average voltage (SOC) of the battery cell 202 at the time of inspection, the charge / discharge amount that can distinguish the change in the average voltage of the battery cell 202 ( The first predetermined amount may be determined.

  Returning to the description of FIG. 1, the battery capacity estimation unit 128 estimates the full charge capacity of the assembled battery 20 from the average cell voltage value and the battery capacity characteristic curve stored in the storage unit 122. The processing in the battery capacity estimation unit 128 will be described in more detail. As described above, the specification capacity of the battery cell 202 is 50 Ah, but due to individual differences of the battery cells 202, it is considered that the actual battery capacity of each battery cell 202 is discretely distributed around 50 Ah. Hereinafter, a battery cell 202 that has a battery capacity of 50 Ah or more that satisfies the specified capacity of the battery cell 202 is referred to as a “normal battery cell”, and a battery cell 202 that does not satisfy the specified capacity of the battery cell 202 is less than 50 Ah as a “deteriorated battery” It is called a cell.

  The battery capacity characteristic curve shown in FIG. 2 is common regardless of the capacity of the battery cell 202. That is, there is no change regardless of whether the battery cell 202 is a normal battery cell or a deteriorated battery cell. However, if the battery capacities of the battery cells 202 are different, even if the same amount of current is charged or discharged, the proportion of the charged / discharged current amount in the battery capacity is different. It will be different.

  Specifically, for example, if a normal battery cell with a battery capacity of 50 Ah discharges a current of 25 Ah from a state where the SOC is 100% (a state where the voltage value is 3), the SOC becomes 50% and the voltage changes to about 2.75. To do. On the other hand, if a deteriorated battery cell with a battery capacity of 40 Ah discharges a current of 25 Ah from a state where the SOC is 100% (a state where the voltage value is 3), the SOC becomes 30% and the voltage changes to about 2.63.

  Thus, the average battery capacity of the battery cell 202 can be estimated by comparing the change in the average voltage before and after charging and discharging with the battery capacity characteristic curve. And the full charge capacity of the assembled battery 20 can be estimated from this average battery capacity. Specifically, for example, by multiplying the average battery capacity of the battery cell 202 by the number of battery cells 202 in the assembled battery 20 (average battery capacity of the battery cell 202 × number of cells), the full charge capacity of the assembled battery 20 is obtained. Can be estimated.

  In the embodiment of the present invention, the battery capacity estimation means 128 estimates the assembled battery capacity using the change in the average cell voltage. For example, the battery capacity estimation means 128 compares the change in the minimum cell voltage with the battery capacity characteristic curve, or Means for estimating the capacity of the assembled battery by comparing the change in voltage and the battery capacity characteristic curve may be used.

  The capacity determination unit 130 determines pass / fail according to the full charge capacity estimated by the battery capacity estimation unit 128. The capacity determination unit 130 determines, for example, whether or not the estimated full charge capacity is equal to or greater than a predetermined capacity. If the estimated full charge capacity is equal to or greater than the predetermined capacity, the capacity is determined to be acceptable. The predetermined capacity can be, for example, the specified battery capacity of the assembled battery 20 or the specified battery capacity of the battery cell 202 (50 Ah in the present embodiment) × the number of battery cells 202. Further, as described later, the predetermined capacity may be changed depending on the temperature.

  The voltage variation measuring unit 132 measures the voltage variation of each battery cell of the assembled battery that has been determined to pass the capacity determining unit 130. The voltage variation measuring means 132, for example, charges or discharges the battery pack 20 with a second predetermined amount of current smaller than the full capacity of the battery pack 20, and the voltage value of each battery cell 202 after charging or discharging. The difference (voltage variation) is measured. More specifically, the voltage variation measuring means 132 controls a charging circuit constituted by the switch circuit 108, the current limiting circuit 106 and the charging power source 104, or a discharging circuit constituted by the switch circuit 112 and the load resistance circuit 110. Then, the battery pack 20 is charged or discharged, and the difference between the voltage values of the respective battery cells 202 after charging or discharging is measured.

  The difference between the voltage values of each battery cell 202 may be a difference between the maximum voltage value and the minimum voltage value among the voltage values of each of the plurality of battery cells 202, or the difference between the voltage values of the battery cells 202. It may be a difference between an average value (average voltage) and a minimum voltage value (or maximum voltage value). Further, the standard deviation may be obtained from the voltage value of each battery cell, and the difference from the standard deviation may be obtained, or the median value may be obtained from the voltage value of each battery cell and may be the difference from the median value. In the following description, the voltage value difference of the battery cell 202 is expressed as a positive number by taking an absolute value or the like.

  The amount of current (second predetermined amount) to be charged or discharged in the voltage variation measuring unit 132 may be determined in the same manner as the first predetermined amount in the average cell voltage measuring unit 126. The first predetermined amount and the second predetermined amount may be different amounts or the same amount.

  Note that at least one of the measurement by the average cell voltage measurement unit 126 and the measurement by the voltage variation measurement unit 132 is the difference between the average voltage or the voltage value in the battery state corresponding to the location where the slope of the battery capacity characteristic curve is relatively large. Measurement may be performed. Specifically, referring to FIG. 2, in the battery capacity characteristic curve of FIG. 2, when the SOC is low (for example, SOC near 0% to 10%), the SOC is high (for example, SOC near 60% to 100%). In comparison, the slope of the battery capacity characteristic curve is relatively large. For this reason, when the measurement is performed in the vicinity of SOC 0% to 10%, the change in voltage before and after charging / discharging becomes larger even when the measurement is performed in the vicinity of SOC 60% to 100% even with the same charge / discharge amount. For this reason, for example, when there is a measurement error during voltage measurement, the influence of the measurement error can be reduced.

  When such a method is adopted, the battery pack 20 is charged or discharged until the battery state corresponding to a location where the slope of the battery capacity characteristic curve is relatively large (SOC 0% to 10% in the example of FIG. 2) is reached. After that, measurement by the average cell voltage measurement unit 126 or measurement by the voltage variation measurement unit 132 is performed.

  The voltage variation determination unit 134 determines that the voltage is acceptable when the voltage variation measured by the voltage variation measurement unit 132 is equal to or less than a predetermined determination line. Originally, if the battery capacity of the battery cell 202 satisfies the specified battery capacity, the voltage difference between the battery cells 202 should be zero near the specified battery capacity. However, in practice, variations in the voltage of the battery cell 202 are allowed due to various factors.

  Here, the charging and discharging of the assembled battery 20 are terminated when any one of the battery cells 202 reaches a predetermined upper limit voltage or lower limit voltage. For this reason, if there is variation in the voltage of the battery cell 202, the battery cell 202 cannot be fully charged / discharged, and the performance of the assembled battery as a whole may not be fully utilized. For this reason, when the voltage variation measured by the voltage variation measuring unit 132 is large, the voltage variation determining unit 134 determines that the assembled battery 20 is unacceptable. The assembled battery 20 determined to be rejected is confirmed as being out of standard as a non-standard product, or re-inspected by a normal inspection to meet quality standards.

  FIG. 3 is an explanatory diagram illustrating an example of a determination line for voltage variation. In the graph of FIG. 3, the vertical axis represents voltage variation (index value), and the horizontal axis represents the estimated value (Ah) of the full charge capacity. FIG. 3 shows an example in which a predetermined determination line (inspection reference value for full charge capacity) is 50 Ah. When the full charge capacity is less than 50 Ah, the short time inspection is rejected (NG) regardless of the magnitude of voltage variation. The assembled battery 20 in which the short-time inspection is rejected is either inspected as a non-standard product and shipped as a product, or undergoes a normal inspection (re-inspection).

  When the full charge capacity is 50 Ah or more, in the example of FIG. 3, the allowable upper limit value of the voltage variation increases as the full charge capacity increases. For example, when the full charge capacity is 50 Ah, a difference up to a voltage of 0.01 is allowed (OK). Further, when the full charge capacity is 52 Ah, a difference of voltage 0.015 is allowed. Note that the voltage variation determination line shown in FIG. 3 is an example, and not only a straight line as shown in FIG. 3 but also a curve or a constant value may be obtained.

  In addition, at least one of a voltage variation determination line and a predetermined capacity (inspection reference value of full charge capacity) may be changed according to the temperature environment to be inspected. It is known that the performance of batteries including the assembled battery 20 changes depending on the temperature. In a mass production factory of the assembled battery 20, it takes time and cost to make the temperature of the measurement environment uniform, and the efficiency is lowered. Therefore, correction of the determination line based on such temperature is effective for improving the accuracy of the short-time inspection. . Specifically, charge / discharge characteristics improve as the temperature increases. Therefore, for example, as shown in FIG. 4, the inspection may be performed by increasing the determination line (predetermined capacity or predetermined value) as the temperature increases.

  In the present embodiment, the assembled battery 20 to be inspected is installed in an air-conditioned room at a constant temperature (for example, 25 ° C.) for a predetermined time (for example, 10 hours), and the temperature in the assembled battery 20 is within a predetermined range (for example, for example). It is assumed that the capacity performance inspection is performed after adjusting the temperature to 20 ° C to 30 ° C. Even in this case, since the temperature in the assembled battery 20 is not constant and has a predetermined range (for example, 20 ° C. to 30 ° C.), the correction of the determination line by the temperature is effective.

  FIG. 4 is an explanatory diagram for explaining the change of the determination line due to temperature. 4A shows a determination line at 20 ° C., FIG. 4B shows a determination line at 25 ° C., and FIG. 4C shows a determination line at 30 ° C. In the graph of FIG. 4, the vertical axis represents voltage variation (index value), and the horizontal axis represents the estimated value (Ah) of the full charge capacity.

  4A to 4C, as the temperature of the assembled battery 20 is higher, the inspection reference value of the full charge capacity and the allowable upper limit value of the voltage variation are larger. Thereby, the characteristic change of the battery due to temperature can be corrected, and the accuracy of inspection can be improved. In FIG. 4, both the inspection reference value of the full charge capacity and the allowable upper limit value of the voltage variation are changed depending on the temperature, but only one of these may be changed depending on the temperature.

  Note that the inspection determination lines (predetermined capacity and predetermined value) as shown in FIGS. 3 and 4 are determined in advance by the inspector or the like based on the characteristics of the battery cell 202 (battery capacity characteristic curve).

  As described above, when the full charge capacity of the assembled battery 20 is equal to or greater than the predetermined capacity by the capacity determination unit 130 and the voltage variation is equal to or less than the predetermined value by the voltage variation determination unit 134, the inspection apparatus 10 Check that the capacity is above the reference capacity. The assembled battery 20 inspected that the battery capacity is equal to or greater than the reference capacity is transferred to the next step of the manufacturing process of the assembled battery 20 as having passed the capacity performance inspection by the short time inspection.

  Further, the inspection device 10 inspects the assembled battery 20 as a non-standard product when the full charge capacity of the assembled battery 20 is equal to or smaller than a predetermined capacity smaller than a predetermined capacity or when the voltage variation is equal to or larger than a certain value larger than a predetermined amount. . Shipment of the assembled battery 20 inspected as a non-standard product is stopped. This is because the assembled battery 20 to be inspected clearly does not meet the quality standard and cannot be shipped.

  Further, when the full charge capacity of the assembled battery 20 is less than a predetermined capacity and greater than or equal to a certain capacity, or when the voltage variation is larger than a predetermined amount and less than a certain value, the inspection apparatus 10 performs a normal inspection on the assembled battery 20 ( Evaluate to perform (re-inspection). This is because the inspection determination line has a higher inspection judgment line than the normal inspection in order to ensure the accuracy of the inspection, and the assembled battery 20 that has failed the time reduction inspection can pass the capacity performance inspection if the normal inspection is performed. It is because there is sex. The assembled battery 20 evaluated in the normal inspection as having a battery capacity equal to or higher than the reference capacity is transferred to the next step of the manufacturing process of the assembled battery 20 as having passed the capacity performance inspection. In addition, shipment of the assembled battery 20 that is evaluated as a non-standard product in the normal inspection is stopped.

  FIG. 5 is a flowchart showing the inspection processing procedure of the inspection apparatus 10. In the flowchart of FIG. 5, numerical values (for example, a predetermined capacity, a predetermined value, etc.) that serve as determination thresholds are represented as a capacity X, a value N, and the like. As described above, prior to the inspection by the inspection apparatus 10, the assembled battery 20 to be inspected is placed in a constant temperature air-conditioned room for a predetermined time, and the temperature in the assembled battery 20 is within a predetermined range (for example, 20 ° C. to 20 ° C.). 30 ° C.).

  In the flowchart of FIG. 5, when the inspection apparatus 10 is instructed to start inspection of the assembled battery 20 (step S501: Yes), first, the charging / discharging unit 124 estimates the full charge capacity of the battery cell 202. Charging / discharging (charging or discharging) is performed (step S502). Next, the average cell voltage measuring unit 126 measures the change in the average voltage of the battery cell 202 before and after charging or discharging (step S503).

  Subsequently, the battery capacity estimation unit 128 estimates the full charge capacity of the assembled battery 20 from the change in the average voltage measured by the average cell voltage measurement unit 126 (step S504). The full charge capacity of the assembled battery 20 can be estimated by, for example, multiplying the average battery capacity of the battery cells 202 by the number of battery cells 202 in the assembled battery 20 (average battery capacity of the battery cells 202 × number of cells). it can.

  The capacity determination unit 130 determines whether or not the full charge capacity of the assembled battery 20 is equal to or greater than a predetermined capacity (capacity X) (step S505). When the full charge capacity of the battery cell 202 is less than the predetermined capacity (capacity X) (step S505: No), the capacity determination unit 130 determines whether or not the full charge capacity is equal to or smaller than a certain capacity (capacity Z) smaller than the predetermined capacity. Is determined (step S506). When the full charge capacity is equal to or less than a certain capacity (capacity Z) (step S506: Yes), the capacity determination unit 130 proceeds to step S511 and evaluates that the assembled battery 20 to be inspected is a nonstandard product. (Step S511), the process according to this flowchart is terminated. Further, when the full charge capacity is larger than the certain capacity (capacity Z) (step S506: No), the capacity determination unit 130 proceeds to step S512 and evaluates to perform a normal inspection on the assembled battery 20 to be inspected. In step S512, the process according to this flowchart is terminated.

  On the other hand, in step S505, when the full charge capacity of the battery cell 202 is equal to or greater than the predetermined capacity (capacity X) (step S505: Yes), the voltage variation measuring unit 132 causes the voltage variation of each battery cell 202 of the assembled battery 20 ( The voltage value difference is measured (step S507).

  Subsequently, the voltage variation determining unit 134 determines whether or not the voltage variation measured by the voltage variation measuring unit 132 is equal to or less than a predetermined value (value N) (step S508). When the voltage variation is equal to or smaller than the predetermined value (value N) (step S508: Yes), the voltage variation determination means 134 evaluates that the capacity performance of the assembled battery satisfies the quality standard (pass) (step S509), and this The process of the flowchart ends.

  On the other hand, when the voltage variation is larger than the predetermined value (value N) (step S508: No), the voltage variation determination means 134 determines whether or not the voltage variation is equal to or larger than a certain value (value M) larger than the predetermined value. (Step S510). When the voltage variation is greater than or equal to a certain value (value M) (step S510: Yes), the voltage variation determination means 134 evaluates that the assembled battery 20 to be inspected is a nonstandard product (step S511), and this flowchart. The process by is terminated. Further, when the voltage variation is smaller than the constant value (value M) (step S510: No), the voltage variation determination means 134 evaluates to perform a normal inspection on the assembled battery 20 to be inspected (step S512), The process according to this flowchart ends.

  As described above, according to the inspection apparatus 10 according to the embodiment, the combination is made from the average cell voltage value of the battery cells 202 constituting the assembled battery 20 and the battery capacity characteristic curve corresponding to the type of the battery cells 202. The full charge capacity of the battery 20 is estimated, and pass / fail is determined. Thereby, compared with the conventional performance inspection method which charges / discharges the assembled battery 20 until it becomes a full charge state or an empty charge state, the performance inspection of the assembled battery 20 can be performed in a short time.

  Moreover, according to the test | inspection apparatus 10, it determines with a pass when the full charge capacity of the assembled battery 20 is a pass (it is more than predetermined capacity), and the voltage variation of each battery cell 202 is below a predetermined | prescribed determination line. As described above, by performing the voltage variation inspection together with the estimation of the full charge capacity, the reliability of the inspection can be improved even in a short time measurement.

  Further, according to the inspection apparatus 10, the inspection determination line is changed according to the temperature of the environment in which the inspection is performed. It is known that the charge / discharge characteristics of the battery change depending on the temperature. By making such a change (correction) depending on the temperature, the reliability of the inspection by the inspection apparatus 10 can be further improved.

  DESCRIPTION OF SYMBOLS 10 ... Battery performance inspection apparatus, 20 ... Assembly battery, 102 ... Voltmeter, 104 ... Power supply for charging, 106 ... Current limiting circuit, 108 ... Switch circuit, 110 ... Load resistance circuit, 112 ... Switch circuit 120... Processing unit 122... Storage means 124... Charge and discharge means 126... Average cell voltage measurement means 128. Variation measuring means 134... Voltage variation determining means 202.

Claims (6)

An inspection method for a battery pack composed of a plurality of battery cells connected in series,
Charging and discharging the assembled battery; and
An average cell voltage measurement step of measuring the voltage of the assembled battery in the middle of the charge / discharge step and obtaining an average cell voltage value obtained by dividing the measured voltage value by the number of cells;
A battery capacity estimation step of estimating a full charge capacity of the assembled battery from the average cell voltage value and a battery capacity characteristic curve according to the type of the battery cell;
A capacity determination step for determining pass / fail according to the full charge capacity estimated in the battery capacity estimation step;
A method for inspecting an assembled battery, comprising: A voltage variation measuring step of measuring a voltage variation of each battery cell of the assembled battery determined to be acceptable in the capacity determining step;
A voltage variation determination step of determining pass / fail according to whether or not the value of the voltage variation is equal to or less than a predetermined determination line ;
2. The assembled battery inspection method according to claim 1, wherein the predetermined determination line is determined based on the battery capacity characteristic curve. The assembled battery inspection method according to claim 2 , wherein the predetermined determination line is changed according to a temperature environment in which the inspection is performed. A battery pack inspection apparatus comprising a plurality of battery cells connected in series,
Charging and discharging means of the assembled battery;
Average cell voltage measuring means for measuring the voltage of the assembled battery in the middle of charging / discharging by the charging / discharging means and obtaining an average cell voltage value obtained by dividing the measured voltage value by the number of cells;
Storage means for storing a battery capacity characteristic curve according to the type of the battery cell;
Battery capacity estimation means for estimating a full charge capacity of the assembled battery from the average cell voltage value and the battery capacity characteristic curve stored in the storage means;
Capacity determination means for determining pass / fail according to the full charge capacity estimated by the battery capacity estimation means;
A battery pack inspection apparatus comprising: Voltage variation measuring means for measuring voltage variation of each battery cell of the assembled battery determined to pass the capacity determining means;
Voltage variation determining means for determining that the voltage variation is acceptable when the voltage variation is equal to or less than a predetermined determination line;
5. The assembled battery inspection apparatus according to claim 4, wherein the predetermined determination line is determined based on the battery capacity characteristic curve. The assembled battery inspection device according to claim 5 , wherein the predetermined determination line is changed according to a temperature environment in which the inspection is performed.

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