JP2014143164A - Method and device for checking secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a secondary battery checking device capable of determining failure of a battery.SOLUTION: A device for checking a secondary battery 10 is provided with a battery element formed by laminating plural stages of positive electrode plates and negative electrode plates via separators together with an electrolyte and comprises: a charger 51 for constant-current charging the discharged secondary battery 10; a charging amount calculation part 54 for calculating a charging amount of the secondary battery 10; a battery voltage determination part 53 for determining whether or not an inter-terminal voltage of the secondary battery 10 reaches a setting voltage; a charging amount comparison part 55 for comparing a charging amount calculation value of the charging amount calculation part 54 and a set charging amount threshold value when the battery voltage determination part 53 determines that the inter-terminal voltage of the secondary battery 10 reaches the setting voltage; a determination part 56 for determining that the battery is faulty when the charging amount calculation value is smaller than the charging amount threshold value according to comparison results of the charging amount comparison part 55; and a result indicator 60 for indicating the determination results.

Description

  The present invention relates to a secondary battery inspection method and inspection apparatus.

  In recent years, secondary batteries have been widely used as batteries for home appliances such as portable devices and batteries for automobiles. In this secondary battery, for example, as shown in FIG. 6, a battery element 4 in which a positive electrode plate 1 and a negative electrode plate 2 as electrodes are laminated in a plurality of stages via a separator 3 is disposed in an electrolyte solution. For example, it is configured by sealing with a laminate film.

  Each of the positive electrode plate 1 and the negative electrode plate 2 includes a current collector and an active material provided on the surface thereof, and the dimension of one side of the positive electrode plate 1 is larger than that of the negative electrode plate 2 as shown in FIG. Also designed to be short.

  In a portion where the active material of the positive electrode plate 1 and the active material of the negative electrode plate 2 face each other, for example, in the case of a lithium ion secondary battery, lithium ions are exchanged and charging / discharging is performed.

  However, when the electrodes are stacked, as shown in FIG. 6C, if the positions of the positive electrode plate 1 and the negative electrode plate 2 are shifted and the facing area is reduced, the designed battery capacity cannot be obtained.

JP 2007-265863 A

  Even if the positive electrode plate 1 and the negative electrode plate 2 are displaced from each other, the negative electrode plate 2 may be formed larger in order to keep the facing area unchanged. However, if the negative electrode plate 2 is excessively enlarged, the battery becomes larger.

  Moreover, it is difficult to judge from the appearance whether the opposing area of the positive electrode plate 1 and the negative electrode plate 2 is as designed due to a positional deviation at the time of electrode lamination.

  For example, in Patent Document 1, local deformation such as wrinkles generated on the surface of an exterior body film adhered to the surface of an electrode laminate constituting a battery element is determined based on scattered light of light irradiated by an irradiation unit. However, it is difficult to judge that the electrode is defective by detecting the displacement of the electrode or the loss of the active material generated in the electrode stack.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a secondary battery inspection method and inspection apparatus that can determine a battery failure.

  The secondary battery inspection method of the present invention for solving the above-described problems is a secondary battery inspection method comprising a battery element formed by laminating a plurality of stages of a positive electrode plate and a negative electrode plate via a separator together with an electrolyte. A charging step for charging a battery in a discharged state at a constant current, a charge amount calculation value charged by the charging step when a voltage between terminals of the battery becomes a set voltage, and a set charge amount And a step of inspecting the battery based on the threshold value.

(1) According to the first to eighth aspects of the invention, it is possible to easily determine whether or not the secondary battery is defective.
(2) According to the second and sixth aspects of the invention, unnecessary charging operation can be avoided when the battery is inspected.
(3) According to the invention described in claims 3 and 7, it is possible to configure a battery having a charging rate larger than zero by performing inspection of the battery without adding another process.
(4) According to the inventions described in claims 4 and 8, the accuracy of determining the defect of the secondary battery is improved.

1 is an external perspective view of a secondary battery to which the present invention is applied. The disassembled perspective view of the secondary battery of FIG. The expanded sectional view along the AA line in FIG. The block diagram of the inspection apparatus of the secondary battery by one example of the present invention. The characteristic view which shows the example of the charge capacity of a day unit in the embodiment which changes a charge amount threshold value based on the charge capacity average value of a secondary battery of this invention. The cross-sectional block diagram of the electrode laminated body of a secondary battery.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments. First, a basic configuration of a secondary battery to which the present invention is applied will be described.

  As a basic configuration of the secondary battery, a positive electrode mixture containing a positive electrode active material and a binder, and a negative electrode mixture containing a negative electrode active material and a binder, respectively, are kneaded to form a positive electrode current collector and a negative electrode current collector. A positive electrode and a negative electrode in which a positive electrode mixture and a negative electrode mixture are coated on a metal foil and an electrode mixture layer is formed on the metal foil are produced as electrodes.

As the positive electrode, a normal positive electrode for a lithium ion secondary battery can be used. For example, as a positive electrode active material, lithium such as LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ , LiNi _1/3 Co _1/3 Mn _1/3 O ₂ , LiNi _1/2 Mn _1/2 O ₄ , LiFePO _4, etc. A composite oxide containing lithium, a transition metal portion of a lithium-containing composite oxide substituted with another element, or a mixture thereof.

  These positive electrode active material and binder material are dispersed and kneaded in N-methyl-2-pyrrolidone (NMP), and then coated on both sides of a current collector such as a 20 μm-thick aluminum foil, for example. And a positive electrode mixture layer is formed.

  As the negative electrode, a normal negative electrode for a lithium ion secondary battery can be used. For example, examples of the negative electrode active material include materials capable of occluding and releasing lithium, such as graphite materials, amorphous carbon materials, silicon materials, and silicon compound materials, and mixtures thereof may be used. A negative electrode active material and a binder material are dispersed and kneaded in N-methyl-2-pyrrolidone (NMP), and then coated on both sides of a current collector such as a copper foil having a thickness of 20 μm, for example. Form a material layer.

  As the separator used in the secondary battery to which the present invention is applied, a normal lithium ion secondary battery separator can be used. For example, a polypropylene or polyethylene-based porous film is preferably used in terms of a thin film, large area, film strength, and film resistance.

As the electrolytic solution of the secondary battery to which the present invention is applied, an ordinary electrolytic solution for a lithium ion secondary battery can be used. For example, the non-aqueous solvent lithium salt can be used a nonaqueous electrolyte solution obtained by dissolving as an electrolyte, a lithium salt, lithium imide _{salt, LiPF 6, LiAsF 6, LiAlCl} 4, LiClO 4, LiBF 4, LiSbF 6 In particular, LiPF ₆ and LiBF ₄ are preferably used. Examples of the lithium imide salt include LiN (C _k F _{2k + 1} SO ₂ ) (C _m F _{2m + 1} SO ₂ ) (k and m are each independently 1 or 2), and these lithium salts Can be used in combination. The non-aqueous solvent is at least one selected from cyclic carbonates, chain carbonates, aliphatic carboxylic acid esters, lactones, cyclic ethers, chain ethers, and organic solvents of their fluorinated derivatives. These organic solvents can be used.

  More specifically, cyclic carbonates: propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate (BC) and derivatives thereof, chain carbonates: dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl Methyl carbonate (EMC), dipropyl carbonate (DPC) and derivatives thereof, aliphatic carboxylic acid esters: methyl formate, methyl acetate, ethyl propionate and derivatives thereof, lactones: γ-butyrolactone, and derivatives thereof, cyclic Ethers: Tetrahydrofuran, 2-methyltetrahydrofuran, chain ethers: 1,2-diethoxyethane (DEE), ethoxymethoxyethane (EME), diethyl ether and their derivatives, others: dimethyl Sulfoxide, 1,3-dioxolane, formamide, acetamide, dimethylformamide, dioxolane, acetonitrile, propylnitrile, nitromethane, ethyl monoglyme, phosphoric acid triester, trimethoxymethane, dioxolane derivative, sulfolane, methylsulfolane, 1,3- Dimethyl-2-imidazolidinone, 3-methyl-2-oxazolidinone, propylene carbonate derivative, tetrahydrofuran derivative, ethyl ether, 1,3-propane sultone, anisole, N-methylpyrrolidone, fluorinated carboxylic acid ester Two or more kinds can be mixed and used. Furthermore, it is also possible to use common, for example, vinylene carbonate (VC) as the electrolyte solution additive.

  The lithium ion secondary battery to which the present invention is applied is a laminate of a negative electrode and a positive electrode with a separator interposed therebetween, or after winding the laminated one, it is inserted into an exterior body and impregnated with an electrolytic solution. Obtained by sealing. At this time, the positive electrode terminal and the negative electrode terminal are joined to the current collector, respectively, and a part of each terminal protrudes outside the exterior body. There is no limitation on the battery shape, and it is possible to take the form of a positive electrode and a negative electrode facing each other with a separator interposed between them, a wound type, a laminated type, etc. There are no particular limitations on the metal can cylindrical type, but a laminate type is more preferable in terms of thickness reduction.

  Next, an example of a specific configuration and shape of a lithium ion secondary battery to which the present invention is applied will be described with reference to FIGS. FIG. 1 is an external perspective view of a secondary battery 10 according to the present embodiment, FIG. 2 is an exploded perspective view, and FIG. 3 is an enlarged cross-sectional view along the line AA in FIG. As shown in FIGS. 1 to 3, the secondary battery 10 has a rectangular flat shape, and the two films 31 and 32 that secretly seal the battery element 20, the battery element 20, and an electrolyte solution (not shown). And have.

  As shown in FIG. 2, the battery element 20 includes a plurality of rectangular positive plates 21 and negative plates 22 that are alternately stacked via separators 23 (FIG. 3).

  A positive electrode extension 24 is drawn out from each positive electrode plate 21, and a negative electrode extension 25 is drawn out from each negative electrode plate 22. Each positive electrode extension 24 is collectively bonded to one end of the positive electrode lead 26, and each negative electrode extension 25 is collectively bonded to one end of the negative electrode lead 27.

  As shown in FIG. 3, the positive electrode active material is applied to both surfaces of the positive electrode plate 21, and the negative electrode active material is applied to both surfaces of the negative electrode plate 22.

  The films 31 and 32 are laminated films having a laminated structure, and each have at least a heat fusion layer, a metal layer, and a protective layer. As shown in FIG. 2, the films 31 and 32 sandwich the battery element 20 from above and below with the heat fusion layer inside, and seal the battery element 20 so that the electrolyte does not leak. Further, the opposing heat-sealing layers of the films 31 and 32 are heat-sealed.

  The other end of the positive electrode lead 26 is drawn outward from one side (short side) of the films 31 and 32. Further, the other end of the negative electrode lead 27 is drawn out from the other one side (short side) of the films 31 and 32.

A specific manufacturing example of the secondary battery 10 is as follows. About the positive electrode plate 21, positive electrode active material (LiMn ₂ O ₄ ), PVdF, and carbon black as a conductive additive were dispersed and kneaded in NMP to prepare a positive electrode mixture slurry. The slurry was coated on a positive electrode current collector (aluminum foil, thickness 20 μm), NMP was removed by drying, and wound to prepare a positive electrode mixture layer roll. The solid content ratio in the positive electrode mixture layer was positive electrode active material: PVdF: conductive aid = 90: 5: 5 (wt%).

  For the negative electrode plate 22, a negative electrode active material (graphite material), PVdF, and carbon black as a conductive additive were dispersed and kneaded in NMP to prepare a negative electrode mixture slurry. Coating the slurry on a negative electrode current collector (copper foil, thickness 20 μm) alternately and repeatedly in an uncoated portion length of 50 mm, a coated portion length of 210 mm, an uncoated portion length of 50 mm, and a coated portion length of 210 mm. Then, NMP was removed by drying and wound up to prepare a negative electrode mixture layer roll. The solid content ratio in the negative electrode mixture layer was negative electrode active material: PVdF: conductive aid = 93: 5: 2 (wt%).

  Then, the positive electrode plate 21 and the negative electrode plate 22 are cut so that the dimensions are 120 mm × 200 mm, and the positive electrode plate 21 and the negative electrode plate 22 are made of a two-layer structure of polyethylene and polypropylene, and have a length of 220 mm, a width of 60 mm, and a thickness. Lamination was performed via a 25 μm separator 23 to prepare an electrode composed of negative electrode / separator / positive electrode / separator / negative electrode. At this time, the battery element 20 was fabricated by stacking so that the number of positive electrodes was 14 and the number of negative electrodes was 15.

  Next, the positive electrode lead 26 and the negative electrode lead 27 are joined to current collectors (the positive electrode extension portion 24 and the negative electrode extension portion 25), respectively, and two aluminum laminate film exterior bodies (films 31 and 32) in which the electrode body is formed as a recess. ). As the outer package, a laminate outer package made of an aluminum laminate film having a three-layer structure of PET / aluminum / polypropylene was used.

Next, in a state in which the positive electrode lead 26 and the negative electrode lead 27 are projected to the outside of the outer package (films 31 and 32), the outer peripheral portion is heat sealed and sealed except for one side other than the electrode lead side, and then the electrolytic solution And heat sealed to produce a laminate type battery. 2 g of an electrolyte solution in which 1 mol / L LiPF ₆ was dissolved as an electrolyte was injected into EC: DEC = 40: 60 (vol%).

  In the present embodiment, the secondary battery configured as shown in FIGS. 1 to 3 is inspected by the inspection apparatus shown in FIG. 4 before the battery is shipped.

  FIG. 4 shows the configuration of a secondary battery inspection device. Between the probe terminals 50P and 50N connected to the positive electrode and the negative electrode of the secondary battery 10 to be inspected, a charger 51 (charging unit) and a voltage measuring device 52 are provided. Are connected in parallel.

  It is assumed that the secondary battery 10 is discharged in advance by energizing a miniature bulb or a resistor before being connected to the probe terminals 50P and 50N. Discharging has the effect that it is not necessary to increase the number of new steps by using the discharging in the step of measuring battery capacity by discharging after full charge.

  The charger 51 charges the discharged secondary battery 10 with a constant current, and the voltage measuring device 52 measures the voltage between the terminals of the secondary battery 10 (voltage between the probe terminals 50P and 50N).

  Reference numeral 53 denotes a battery voltage determination unit that determines whether or not the measurement voltage of the voltage measuring device 52 has reached a set voltage, for example, a voltage corresponding to 10% of a charge rate (SOC: State of Charge).

  The battery voltage determination unit 53 includes, for example, a voltage comparator that compares the measured voltage of the voltage measuring device 52 with the set voltage, and the comparator when the measured voltage reaches the set voltage or the measured voltage exceeds the set voltage. The output is output as a determination output indicating that the voltage between the terminals of the battery has reached the set voltage, and the charging operation of the charger 51 is stopped by the determination output.

  A charge amount calculation unit 54 calculates a charge amount (charge capacity) from the start of charging of the secondary battery 10 until the determination output is output from the battery voltage measurement unit 53, that is, the battery terminal voltage is set. The charge amount calculation value until it is determined that the voltage has been reached is output.

  The amount of charge of the secondary battery 10 is calculated by current value (constant) × time, and the current value is detected by, for example, a shunt resistor or a digital multimeter (not shown) inserted in the electric path connecting the charger 51 and the secondary battery 10 The detected current value is used for the charge amount calculation.

  55 is a charge amount comparison unit that compares the charge amount calculation value output from the charge amount calculation unit 54 with a set charge amount threshold value.

  56, based on the comparison result of the charge amount comparison unit 55, if the charge amount calculated value is smaller than the charge amount threshold value, it is determined that the battery is defective, and the charge amount calculated value is charged. The determination unit determines that the product is non-defective if it is equal to or greater than the amount threshold value.

  Reference numeral 60 denotes a result display device such as a display for displaying the determination result of the defective product and the non-defective product determined by the determination unit 56.

  In this embodiment, the battery voltage determination unit 53, the charge amount calculation unit 54, the charge amount comparison unit 55, and the determination unit 56 are configured as a calculator 70 by a computer.

  Next, an example of a procedure of an inspection method using the secondary battery inspection apparatus configured as described above will be described.

  Step S1: First, the secondary battery 10 is discharged.

  Step S2: The secondary battery 10 that has been discharged is connected to the terminals 50P and 50N, and constant current charging is started by the charger 51. The voltage measuring device 52 measures the voltage between the terminals of the secondary battery 10.

  Step S <b> 3: The charge amount calculation unit 54 starts calculating the charge amount of the secondary battery 10.

  Step S4: When the measured voltage of the voltage measuring device 52 becomes the set voltage, the battery voltage determining unit 53 outputs a determination output indicating that the battery terminal voltage has reached the set voltage, and stops the charging operation of the charger 51. Let

  Step S5: The charge amount calculation unit 54 outputs the charge amount calculation value calculated until the determination output is output from the battery voltage determination unit 53 in step S4.

  Step S6: The charge amount comparison unit 55 compares the charge amount calculation value output in step S5 with the set charge amount threshold value.

  Step S7: The determination unit 56 determines “defective product” if the charge amount calculated value <charge amount threshold value, and “good” if the charge amount calculated value ≧ charge amount threshold value.

  Step S8: The result display 60 displays “defective product” and “good product”.

  Note that the reason why the secondary battery 10 is charged to a voltage corresponding to, for example, a charging rate (SOC) of 10% during the inspection is to prevent the charging rate from becoming negative due to natural discharge after shipment.

  If the facing area of the stacked positive electrode plate 21 and negative electrode plate 22 in the secondary battery 10 is small, the electric resistance increases when the constant current charging is performed, and the time for flowing at a constant current is shortened. It is estimated that the charge amount calculation value from the start of charging until the set voltage is reached becomes smaller than the set charge amount threshold value because charging cannot be performed.

  Therefore, by performing the inspection according to the procedure of steps S1 to S8 using the inspection apparatus of FIG. 4, it is possible to determine “defective product” and “good product” of the secondary battery 10.

  The inspection method of the present invention is not limited to the case where the positions of the positive electrode plate and the negative electrode plate are shifted and the opposing area is small, but the active material of the positive electrode plate and the negative electrode plate is dropped (granulated) and the portion is filled. Similarly, when the battery does not contribute to the discharge, the battery failure can be determined.

  In the embodiment example of FIG. 4, the charging operation of the charger 51 is stopped by the output of the battery voltage determination unit 53, so that unnecessary charging operation can be avoided.

  Moreover, the battery in a charged state can be manufactured and shipped by performing the inspection of the battery without adding another process.

  In the embodiment example of FIG. 4, the charge amount threshold value is set to a single value. However, the present invention is not limited to this, and as another embodiment example, the charge capacity average value of a plurality of secondary batteries in the same lot is used. It may be changed accordingly.

  That is, the initial charge capacity is measured for each of a plurality of secondary batteries having the same specifications and the same manufacturing date, and the charge amount threshold value is set based on the average value of the initial charge capacity obtained by taking the average.

  As a specific example, in order to prevent the stacking error of the electrodes in the secondary battery, a value smaller than the initial charge capacity average value is set as a threshold value (charge amount threshold value), and when the initial charge capacity is smaller than the threshold value, the stacking shift is reduced. I decided to judge.

  The threshold is determined by, for example, threshold = initial charge capacity average value × coefficient k, and the value of the coefficient k is set from the allowable range of stacking misalignment.

  In the present embodiment example, the charge amount threshold value determined based on the average charge capacity value for each lot is stored in, for example, the memory in the arithmetic unit 70 of FIG. The charge amount comparison unit 55 compares the charge amount threshold value in the memory set corresponding to the lot of the target battery and the charge amount calculation value calculated by the charge amount calculation unit 54, so that the secondary value is obtained. A “defective” or “non-defective” battery is determined.

  FIG. 5 shows an example of the charge capacity in units of days in the present embodiment example, the horizontal axis shows the measurement date of the charge capacity, and the vertical axis shows the value of the initial charge capacity.

  The upper graph in FIG. 5 is the daily initial charge capacity average value (Ave), and the middle graph is the daily initial charge capacity minimum value (Min) (calculated by the charge amount calculation unit 54 during the secondary battery inspection). The lower graph shows the daily threshold values (charge amount threshold values) set based on the initial charge capacity average value.

  In FIG. 5, the initial charge capacity average value is different for each measurement day, which is presumed to be due to manufacturing variations due to differences in manufacturing dates, measurement variations due to temperature conditions, and the like.

  In FIG. 5, the threshold value is set according to the initial charge capacity average value. However, for example, on the measurement dates D1 and D2, the initial charge capacity minimum value is smaller than the threshold value. In this case, the stacking deviation NG (“ It is determined that the product is defective.

  As described above, according to the present embodiment, the charge amount threshold value is set in accordance with the average charge capacity value that is different for each lot, so that the accuracy of determination of non-defective and defective secondary batteries is improved. .

  The inspection method for a secondary battery according to the present invention is superior to other conventional inspection methods as follows. That is, as a result of visual inspection, the secondary battery determined to be “non-defective” was inspected according to the present invention using the apparatus of FIG. 4 and was determined to be “defective”. This indicates that the inspection according to the present invention can determine defects inside the battery that cannot be visually determined. As for this visual inspection, even if active material degranulation or separator wrinkles are generated inside the battery element laminate, the appearance of the outer shape does not appear when the number of laminates is large. The inspection method is effective.

  Further, in the self-discharge inspection, if the positions of the positive electrode plate and the negative electrode plate are shifted and the facing area is small, the electrical resistance is increased and the self-discharge is reduced. It can be considered that the determined battery is determined as “good”.

  In DC resistance inspection DCR (Direct Current Resistance), the voltage change is often performed in a range that does not depend on the current value, and the voltage change when discharging for a predetermined time at a low current is measured, but the current is low. For this reason, since the opposing area is reduced due to the positional deviation between the positive electrode plate and the negative electrode plate, the influence is small, and it is difficult to distinguish between “defective product” and “good product”.

  On the other hand, according to the inspection method of the present invention, when the facing area is small due to the displacement of the positive electrode plate and the negative electrode plate, the time required to flow at a constant current is shortened due to the increase in electrical resistance, so that the amount of charge is reliably increased. Since it is reflected, it can be determined as “defective product”.

DESCRIPTION OF SYMBOLS 10 ... Secondary battery 20 ... Battery element 21 ... Positive electrode plate 22 ... Negative electrode plate 23 ... Separator 24 ... Positive electrode extension part 25 ... Negative electrode extension part 26 ... Positive electrode lead 27 ... Negative electrode lead 31, 32 ... Film 50P, 50N ... Terminal DESCRIPTION OF SYMBOLS 51 ... Charger 52 ... Voltage measuring device 53 ... Battery voltage determination part 54 ... Charge amount calculating part 55 ... Charge amount comparison part 56 ... Determination part 60 ... Result indicator 70 ... Calculator

Claims (8)

A method for inspecting a secondary battery comprising a battery element, in which a positive electrode plate and a negative electrode plate are laminated in multiple stages via a separator, together with an electrolyte,
A charging step for charging a discharged battery at a constant current;
A step of inspecting the battery based on a charge amount calculation value charged by the charging step and a set charge amount threshold when the voltage between the terminals of the battery becomes a set voltage;
A method for inspecting a secondary battery, comprising: The secondary battery inspection method according to claim 1, further comprising a step of stopping charging in the charging step when a voltage between the terminals of the battery reaches a set voltage. 3. The method for inspecting a secondary battery according to claim 1, wherein the set voltage of the terminal voltage is set to a voltage between terminals of a battery having a charging rate larger than zero. 4. The secondary battery according to claim 1, wherein the charge amount threshold value is set according to an average charge capacity value of a plurality of secondary batteries in the same lot. 5. Inspection method. An inspection apparatus for a secondary battery comprising a battery element, in which a positive electrode plate and a negative electrode plate are laminated in multiple stages via a separator, together with an electrolyte,
A charging unit for charging a discharged battery with a constant current; and
A charge amount calculation unit for calculating the charge amount of the battery;
A battery voltage determination unit that determines whether or not the terminal voltage of the battery has reached a set voltage;
Charge amount comparison for comparing the charge amount calculation value of the charge amount calculation unit and the set charge amount threshold when the battery voltage determination unit determines that the voltage between the terminals of the battery has reached a set voltage And
When the comparison result of the charge amount comparison unit is smaller in the charge amount calculation value than the charge amount threshold, the determination unit determines that the battery is defective,
An inspection apparatus for a secondary battery, comprising: The said battery voltage determination part has a function which stops the charging operation of the said charging part, when it determines with the voltage between terminals of a battery becoming a setting voltage. Secondary battery inspection device. The inspection apparatus for a secondary battery according to claim 5 or 6, wherein the set voltage determined by the battery voltage determination unit is set to a terminal voltage of a battery having a charging rate larger than zero. The secondary battery according to any one of claims 5 to 7, wherein the charge amount threshold value is set according to an average charge capacity value of a plurality of secondary batteries in the same lot. Inspection device.

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