JP2021157962A - Secondary battery inspection method and secondary battery inspection device - Google Patents

Abstract

To provide a secondary battery inspection method and a secondary battery inspection device, which are capable of inspecting, in a short time, with high accuracy and at low cost, the presence or absence of a conductive foreign matter in a secondary battery that includes a case and a laminate including a positive electrode sheet, a separator and a negative electrode sheet laminated therein.SOLUTION: A secondary battery inspection method includes: a preparation step (step S1) of preparing a state where a case is pressed from a first both end surfaces and vibration is applied to a laminate from a direction parallel to the first both end surfaces, the first both end surfaces being both end surfaces perpendicular to the lamination direction of the laminate in the case; and an inspection step (step S2) of applying voltage to a secondary battery in such a state and inspecting the presence or absence of a conductive foreign matter.SELECTED DRAWING: Figure 3

Description

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

In the secondary battery, the power generator is formed by a structure in which the separator is sandwiched between the positive electrode sheet and the negative electrode sheet. In addition, the battery capacity of a secondary battery is determined by the size of the area of the generator. In the secondary battery, various methods of storing the generator in the secondary battery have been considered in order to increase the battery capacity per volume of one secondary battery (hereinafter referred to as capacity efficiency). As one of the storage methods, there is a wound body structure in which a sheet-shaped power generator having a large area is wound into a tubular shape. Further, as another storage method, there is a laminated structure in which a plurality of positive electrode plates, a plurality of negative electrode plates, and a plurality of separators are laminated so that the separator is sandwiched between the positive electrode sheet and the negative electrode sheet.

In such a secondary battery, there is a risk that conductive foreign matter may be mixed in the manufacturing process, particularly in the process of storing the laminated body (laminated electrode body) to be the power generator in the case. Conductive foreign matter mixed between the positive electrode and the negative electrode may cause a short circuit due to long-term use of the secondary battery.

Patent Document 1 includes an electrode body having a positive electrode, a negative electrode, and a separator interposed between the positive and negative electrodes, and a battery case accommodating the electrode body, and inspects a secondary battery in a state in which no electrolytic solution is injected. The inspection method to be performed is described. The inspection method described in Patent Document 1 includes a step of holding the battery under pressure and heating, and a step of applying a voltage to the secondary battery while being pressurized to detect the presence or absence of conductive foreign matter.

JP-A-2018-022564

However, in the inspection method described in Patent Document 1, not only it takes time to hold the furnace under pressure and heating for a certain period of time, but also maintenance of the furnace for heating is costly.

The present invention has been made to solve such a problem, and inspects the presence or absence of conductive foreign matter in a secondary battery provided with a laminate and a case in which a positive electrode sheet, a separator, and a negative electrode sheet are laminated. It is an object of the present invention to provide a secondary battery inspection method and a secondary battery inspection device that can be carried out in a short time, with high accuracy and at low cost.

The secondary battery inspection method according to one aspect of the present invention includes a positive electrode sheet, a negative electrode sheet, a laminate having a separator sandwiched between the positive electrode sheet and the negative electrode sheet, and a case for accommodating the laminate. A secondary battery inspection method for inspecting a secondary battery in a state in which an electrolytic solution has not been injected, wherein both end faces perpendicular to the stacking direction of the laminate in the case are set as first end faces. A preparatory step of pressing the case from the first both end faces and preparing a state in which the laminate is vibrated from a direction parallel to the first end faces, and applying a voltage to the secondary battery in the state. It is provided with an inspection process for inspecting the presence or absence of conductive foreign matter.

In the secondary battery inspection method according to this aspect, the presence or absence of conductive foreign matter is inspected in a state where the secondary battery is not only pressed from the first end surface but also vibrated from a direction parallel to the first end faces. Therefore, according to this secondary battery inspection method, the presence or absence of conductive foreign matter in the secondary battery can be inspected in a short time, with high accuracy, and at low cost.

Further, the vibration may include vibration along the stretching direction when the separator is manufactured. The separator is easily torn in the stretching direction, but the presence or absence of conductive foreign matter can be inspected in such a state of being easily torn, and defective products can be easily removed.
Further, the vibration can be assumed to be vibration caused by ultrasonic waves generated by an ultrasonic generator. As a result, preparations for inspection can be easily performed.
Further, the frequency of the vibration may be the frequency of the vibration generated during the operation of the device equipped with the secondary battery. This makes it possible to inspect for short circuits when the secondary battery is mounted on the device, and if defective products with conductive foreign matter are removed, the occurrence of defective secondary batteries when mounted on the device can be suppressed. be able to.

Further, the secondary battery inspection method further includes a setting step of setting at least one value of the frequency and direction of the vibration, and the preparation step further includes vibration based on the value set in the setting step of the laminated body. Can be prepared for the condition given to. In this secondary battery inspection method, at least one of the device on which the secondary battery is mounted and the stretching direction of the separator whose tearability varies depending on the stretching direction at the time of manufacturing can be set. Therefore, according to this secondary battery inspection method, it is possible to inspect at least one of the secondary battery and the device on which the secondary battery is mounted for the presence or absence of a conductive foreign substance that causes a defect.

The secondary battery inspection device according to another aspect of the present invention is a case for accommodating a positive electrode sheet, a negative electrode sheet, a laminate having a separator sandwiched between the positive electrode sheet and the negative electrode sheet, and the laminate. A secondary battery inspection device for inspecting a secondary battery in a state in which an electrolytic solution has not been injected. A pressing portion that presses the case from the first both end surfaces, a vibrating portion that vibrates the laminated body from a direction parallel to the first end surfaces, and a vibrating portion that presses the case with the pressing portion and applies the vibration with the vibrating portion. In this state, the secondary battery is provided with an inspection unit for inspecting the presence or absence of conductive foreign matter by applying a voltage to the secondary battery.

In the secondary battery inspection device according to this aspect, the presence or absence of conductive foreign matter is inspected in a state where the secondary battery is not only pressed from the first end surface but also vibrated from a direction parallel to the first end faces. Therefore, according to this secondary battery inspection device, the presence or absence of conductive foreign matter in the secondary battery can be inspected in a short time, with high accuracy, and at low cost.

Further, the vibration may include vibration along the stretching direction when the separator is manufactured. The separator is easily torn in the stretching direction, but the presence or absence of conductive foreign matter can be inspected in such a state of being easily torn, and defective products can be easily removed.

Further, the secondary battery inspection device includes a setting unit for setting at least one value of the frequency and direction of the vibration, and the vibration unit transmits vibration based on the value set by the setting unit to the laminated body. Can be given. In this secondary battery inspection device, at least one of the device on which the secondary battery is mounted and the stretching direction of the separator whose tearability varies depending on the stretching direction at the time of manufacturing can be set. Therefore, according to this secondary battery inspection device, it is possible to inspect at least one of the secondary battery and the device on which the secondary battery is mounted for the presence or absence of a conductive foreign substance that causes a defect.

Further, in the above-described secondary battery inspection method and secondary battery inspection device, the laminated body is a laminated body having a wound structure that is housed in the case in a state of being flatly wound, and the stacking direction is , It can be assumed that it is in the minor axis direction of the laminated body of the wound body structure. This makes it possible to inspect the secondary battery containing the laminated body of the wound structure for the presence or absence of conductive foreign matter.

Alternatively, in the above-mentioned secondary battery inspection method and secondary battery inspection device, the laminated body is housed in the case with the positive electrode sheet, the separator, and the negative electrode sheet laminated in parallel. , Can be. This makes it possible to inspect the secondary battery containing the laminated body having a laminated structure for the presence or absence of conductive foreign matter.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to inspect the presence or absence of conductive foreign matter in a secondary battery provided with a laminate and a case in which a positive electrode sheet, a separator, and a negative electrode sheet are laminated in a short time, with high accuracy, and at low cost. A secondary battery inspection method and a secondary battery inspection device can be provided.

It is a figure which shows an example of the appearance of the non-aqueous secondary battery as the inspection target of the non-aqueous secondary battery inspection method which concerns on embodiment. It is the schematic which shows an example of the laminated body housed in the case of the non-aqueous secondary battery of FIG. It is the schematic which shows an example of the laminated body housed in the case of the non-aqueous secondary battery of FIG. It is a flow diagram for demonstrating an example of the non-aqueous secondary battery inspection method which concerns on embodiment. It is a figure which shows one configuration example of the inspection apparatus for carrying out the inspection method of FIG. It is a conceptual diagram for demonstrating the inspection with respect to the laminated body carried out in the inspection apparatus of FIG. It is a figure which shows the other structural example of the inspection apparatus for carrying out the inspection method of FIG. It is a figure which shows the result of inspection by the inspection method which concerns on embodiment, and the result of inspection by the inspection method which concerns on a comparative example.

Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments. Further, in order to clarify the explanation, the following description and drawings have been simplified as appropriate. Further, in the embodiment, the same or equivalent elements may be designated by the same reference numerals, and duplicate description may be omitted as appropriate.

(Embodiment)
The inspection method according to the embodiment will be described by taking a non-aqueous secondary battery such as a lithium ion secondary battery as an example of the secondary battery to be inspected. First, the inspection target will be described with reference to FIGS. 1 to 3. FIG. 1 is a diagram showing an example of the appearance of a non-aqueous secondary battery as an inspection target of the non-aqueous secondary battery inspection method according to the embodiment.

As shown in FIG. 1, the non-aqueous secondary battery 1 to be inspected in the present embodiment can include a case 10, a lid 11, a negative electrode pole column 12, and a positive electrode pole column 13. An assembled battery can be formed by combining a plurality of the non-aqueous secondary batteries 1 illustrated in FIG. 1, and the non-aqueous secondary battery 1 can be one cell of the assembled battery.

The case 10 houses a power generator that stores the electrical energy of the non-aqueous secondary battery 1. The lid 11 is a lid for sealing the generator to the case 10. The case 10 and the lid 11 can be made of, for example, aluminum or an alloy thereof. The negative electrode pole column 12 and the positive electrode pole column 13 are electrodes that are electrically connected to the power generation body in the case 10 and are for inputting and outputting current to the power generation body. Further, as shown in FIG. 1, the negative electrode pole pillar 12 and the positive electrode pole pillar 13 can be provided so as to protrude from one end surface (outlet end surface) of the case 10.

Although not shown in FIG. 1, in the non-aqueous secondary battery 1, the lid 11 has a take-out hole for taking out the negative electrode pole column 12 and the positive electrode pole pillar 13 attached to the power generator housed in the case to the outside of the case. Provided. Then, the negative electrode pole pillar 12 and the positive electrode pole pillar 13 are joined to the current collecting component provided in the case through the take-out hole provided in the lid 11. The negative electrode pole pillar 12 and the positive electrode pole pillar 13 are examples of the positive electrode terminal and the negative electrode terminal led out from the lead-out end face, respectively.

The inspection target in the present embodiment is a laminated body (laminated electrode body) constituting the power generator in a state of being housed in the case 10 of the non-aqueous secondary battery 1, and an example of the structure of the laminated body is described. This will be described with reference to FIGS. 2 and 3. FIG. 2 is a schematic view showing an example of a laminated body housed in the case 10 of the non-aqueous secondary battery 1 of FIG. 1, and FIG. 3 is a schematic view showing another example of the laminated body housed in the case 10. Is.

As shown in FIG. 2, the laminate 20 housed in the case 10 has a positive electrode sheet 21, a negative electrode sheet 23, and a separator 22 sandwiched between the positive electrode sheet 21 and the negative electrode sheet 23.

The positive electrode sheet 21 and the negative electrode sheet 23 have active material coating regions 21a and 23a constituting the respective electrodes, respectively. For example, the positive electrode sheet 21 is coated with _{, for example, LiCoO 2} , LiMn ₂ O ₄ , LiNiO _{2, or the like as an active material.} Further, the negative electrode sheet 23 is coated with, for example, graphite (C), titanate (Li ₄ Ti ₅ O ₁₂ ) or the like as an active material. Further, the positive electrode sheet 21 and the negative electrode sheet 23 can have tab portions 21b and 23b of the active material uncoated region having a shape protruding from the active material coated regions 21a and 23a, respectively.

The number of positive electrode sheets 21 and the number of negative electrode sheets 23 are not limited. The stacking direction of the laminated body 20 can be the direction shown in FIG. In order to function as a power generator, the positive electrode sheet 21 and the negative electrode sheet 23 can be alternately laminated in the laminated body 20, and the separator 22 is sandwiched between the positive electrode sheet 21 and the negative electrode sheet 23. Further, the separator 22 can be laminated on the electrode plate (positive electrode sheet 21 or negative electrode sheet 23) also on the outside of one end or both ends of the laminated body 20.

Further, the laminated body 20 may have a layer (adhesive layer) for bonding between the positive electrode sheet 21, the separator 22, and the negative electrode sheet 23. The adhesive layer can have an adhesive such as a thermoplastic resin. The adhesive can be applied to the separator 22 in advance, or can be applied to the positive electrode sheet 21 and the negative electrode sheet 23 in advance, and in such a state, the separator 22, the positive electrode sheet 21, and the negative electrode sheet 23 are applied. The laminated body 20 can be manufactured by laminating them. In addition, a tape such as PP (polypropylene) may be wound around the laminated body 20 only at the end portion or more than once.

The laminated body 20 shown in FIG. 2 is a so-called laminated body having a laminated structure in which the positive electrode sheet 21, the separator 22, and the negative electrode sheet 23 are housed in the case 10 in a state of being laminated in parallel. However, the inspection target by this inspection method is not limited to this.

For example, the non-aqueous secondary battery 1 in which the laminated body having a wound structure such as the laminated body 30 shown in FIG. 3 is housed in the case 10 can be the inspection target. In this case, the stacking direction is the minor axis direction of the laminated body 30 having a wound structure.

The laminated body (rolled electrode body) 30 of this wound body structure (flat wound type) is, for example, a laminated body in which a separator, a positive electrode sheet, a separator, a negative electrode sheet, and a separator are laminated and wound flat. be. For example, the laminated body 30 can be configured by laminating a positive electrode and a negative electrode via a separator, winding the laminated body 30, and then flattening the laminated body 30. On the positive electrode sheet and the negative electrode sheet, as in the example of FIG. 2, the active material coated region (here, only the active material uncoated region 32 on the negative electrode side is exposed) and the active material uncoated portion 33, 34 is formed. Further, the active material uncoated portions 33 and 34 are provided with a lead-out electrode 35 for the positive electrode and a lead-out electrode 36 for the negative electrode, respectively. A tape such as PP may be wrapped around the laminated body 30.

The laminate 30 can be stored in the case 10 in the direction shown in FIG. 3 or can be stored in the case 10 with the axial direction of winding facing up and down, although it depends on the positions of the drawer electrodes 35 and 36. .. The structure of the wound electrode body is the same as that of a general wound electrode body.

Such a laminate 20 or 30 is housed in a case 10 in order to function as a power generator, and a non-aqueous electrolytic solution such as an organic solvent is injected from a liquid injection port (not shown) to impregnate the laminate 20 or 30. Let me. The liquid injection port may be, for example, a hole formed in the lid 11 before attaching the negative electrode pole column 12 and the positive electrode pole pillar 13. Further, in the laminated body 20 or 30, the non-aqueous electrolytic solution passes from the end face of the laminated body 20 or 30 between the electrode plate and the separator 22 (through the adhesive layer if there is an adhesive layer), and the laminated body 20 Alternatively, by impregnating with 30, it can function as a power generator.

The non-aqueous electrolyte solution is a composition in which a supporting salt is contained in a non-aqueous solvent. Here, as the non-aqueous solvent, one or more kinds of materials selected from the following groups can be used. The above group consists of propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC) and the like. Supporting salts include LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAsF ₆ , LiCF ₃ SO ₃ , LiC ₄ F ₉ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiC (CF ₃ SO ₂ ) ₃ , LiI and the like. One or more selected lithium compounds (lithium salts) can be used. Further, it is assumed that a film-forming agent such as lithium bisoxalate borate (LiBOB) is added to the non-aqueous electrolytic solution.

Next, an inspection method (hereinafter, this inspection method) and an inspection apparatus according to the present embodiment in which such a non-aqueous secondary battery 1 is an inspection target will be described with reference to FIGS. 4 to 8. FIG. 4 is a flow chart for explaining an example of the non-aqueous secondary battery inspection method according to the present embodiment. Further, FIG. 5 is a diagram showing a configuration example of an inspection device for carrying out the inspection method of FIG. 4, and FIG. 6 is a concept for explaining an inspection of a laminated body carried out in the inspection device of FIG. It is a figure.

This inspection method targets the non-aqueous secondary battery 1 in which the non-aqueous electrolyte solution has not been injected, and includes a preparation step (step S1) and an inspection step (step S2). Prior to explaining these steps, an inspection device for carrying out this inspection method will be described. In the following description, an example in which the non-aqueous secondary battery 1 in which the laminated body 30 is housed in the case 10 is targeted for inspection will be described as the laminated body, but the non-aqueous secondary battery 1 in which the laminated body 20 is housed will be described. But the same is true.

For example, as shown in FIG. 5, the inspection device 50 for carrying out this inspection method can include a pair of pressure plates 51 and 52, an ultrasonic generator 53, and an inspection unit 54. The pair of pressure plates 51 and 52 is an example of a pressing portion that presses the case 10 from the first both end surfaces as shown by the thick arrows indicating the pressing direction. Here, the first both end faces refer to both end faces perpendicular to the stacking direction of the laminated body 30 in the case 10, and refer to the two widest facing faces of the case 10 as referred to in FIG. A pair of pressure plates 51 and 52 are used to sandwich the laminated body 30 from both sides, but a pedestal may be used instead of simply one of the pressure plates.

The ultrasonic generator 53 is an example of a vibrating portion that vibrates the laminated body 30 from a direction parallel to the first both end faces. The ultrasonic generator 53 generates ultrasonic waves and vibrates the laminated body 30 from a direction parallel to the first both end surfaces by the ultrasonic waves. If a conductive foreign matter M is contained therein, the conductive foreign matter is contained therein. Vibration by ultrasonic waves can be applied to M as well. Since the arrangement of the ultrasonic generator 53 with respect to the non-aqueous secondary battery 1 can be easily changed, it can be said that vibration can be easily applied. Therefore, the inspection can be easily prepared by using the ultrasonic generator 53.

Further, the vibration direction can be switched by arranging the ultrasonic generator 53 at a plurality of different positions or by making the position movable by using one ultrasonic generator 53. It can also be configured in.

The inspection unit 54 inspects the presence or absence of the conductive foreign matter M by applying a voltage to the non-aqueous secondary battery 1 in a state of being pressed by the pressing unit and vibrating by the vibrating unit. In the inspection unit 54, for example, a voltage is applied between the positive electrode pole column 13 which is an example of the positive electrode terminal and the negative electrode pole column 12 (or the case 10 connected to the negative electrode side) which is an example of the negative electrode terminal.

In fact, as shown in FIG. 6, in the laminated body 30, the positive electrode sheet 41, the separator 42, and the negative electrode sheet 43 are laminated, and the laminated body 30 is wound in such a laminated state, but the conductive foreign matter M is mixed. Sometimes. Specifically, when the laminated body 30 is inserted into the case 10, the conductive foreign matter M is placed between the separator 42 and the negative electrode sheet 43, or between the separator 42 and the positive electrode sheet 41, as shown in FIG. May be mixed in. In FIG. 6, only the positive electrode sheet 41, the separator 42, and the negative electrode sheet 43 in the central portion are schematically shown in order to pay attention only to the stacking direction in the laminated body 30, and the case 10 is also omitted.

When the conductive foreign matter M is present, the conductive foreign matter M enters the torn portion of the separator 42 by vibration and pressing, and the positive electrode sheet 41 and the negative electrode sheet 43 pass through the conductive foreign matter M with respect to the applied voltage. Will cause electrical contact and cause a short circuit. The inspection unit 54 has a function of measuring, for example, a current value, and determines the presence or absence of a conductive foreign substance depending on whether or not the voltage value indicates a short circuit. Of course, the inspection unit 54 may be configured to determine the presence or absence of a conductive foreign substance based on, for example, a resistance value, a voltage value, or the like, or by another method.

Using such an inspection device 50, in step S1 which is a preparation step, a state in which the case 10 is pressed from the first both end faces and the laminated body 30 is vibrated from a direction parallel to the first end faces is prepared. .. Here, as described above, the first both end faces are both end faces perpendicular to the stacking direction of the laminated body 30 in the case 10. For example, the pressing can be performed by a pair of pressure plates 51, 52, and the vibration can be applied by the ultrasonic generator 53.

Then, in step S2, which is an inspection step, a voltage is applied to the non-aqueous secondary battery 1 in a state where such pressure and vibration are applied, and the presence or absence of conductive foreign matter is inspected.

In this inspection method, the presence or absence of a conductive foreign substance M that may cause a short circuit while not only pressing the non-aqueous secondary battery 1 from the first end surface but also applying vibration from a direction parallel to the first both end surfaces. Inspect. That is, in this inspection method, mainly by applying a parallel force as well as a vertical force to the separator 42, a short circuit due to the conductive foreign matter M is likely to occur, and the detection sensitivity is improved.

Therefore, according to this inspection method, the inspection for the presence or absence of the conductive foreign matter M in the non-aqueous secondary battery 1 can be performed in a shorter time and at a lower cost than in the case where heating is required. Further, according to this inspection method, since the inspection is carried out in a state where not only pressing but also vibration is applied to cause a short circuit due to the conductive foreign matter M, the inspection can be carried out with high accuracy.

In particular, it is preferable that the vibration given by the vibrating portion of the ultrasonic generator 53 or the like includes the vibration along the stretching direction when the separator 42 is manufactured. This utilizes the fact that the separator 42 is easily torn in the stretching direction (weak strength), and inspects for the presence or absence of conductive foreign matter in a state where vibration is applied in the direction of such weak strength. be. As a result, when the conductive foreign matter M is present, the separator 42 is easily torn at that portion (thus, the positive electrode sheet 41 and the negative electrode sheet 43 are easily short-circuited), so that the conductive foreign matter M can be easily detected, that is, It is possible to easily remove the defective non-aqueous secondary battery 1.

In FIGS. 5 and 6, among the planes perpendicular to the first end faces, the end faces on the electrode lead-out side (out-out end faces) in the case 10 and the end faces parallel to the end faces (hereinafter, the second end faces) are different. An example of applying vibration from a vertical direction was given. In this example, the case 10 is a substantially rectangular parallelepiped except for the terminal lead-out portion, and the separator 42 is manufactured by being stretched in a direction perpendicular to the second end faces and parallel to the first end faces. In some cases, it can be said that the detection accuracy of the conductive foreign matter M can be particularly improved. As a specific frequency, 10 kHz or more is preferable, and 30 kHz or more is more preferable.

Further, although the description has been made on the premise that the separator 42 is uniaxially stretched, the same can be applied even if the separator 42 is stretched along two or more axes. In that case, it is preferable to apply the vibration to all of the shafts, but it is also preferable to apply the vibration in the direction of a part of the shafts. In that case, it is preferable to select the shaft having the higher stretching ratio.

Next, another configuration example of the inspection device will be described with reference to FIG. 7. FIG. 7 is a diagram showing another configuration example of the inspection device for carrying out the inspection method of FIG.

The inspection device 70 shown in FIG. 7 includes vibration units 73a and 73b sandwiched from both ends so as to physically move and vibrate the non-aqueous secondary battery 1 as a vibration unit, and the other parts are the same as the inspection device 50. A pair of pressure plates 51, 52 and the like, which are not shown in the above, and an inspection unit 54 are provided. In this way, the vibrating portions 73a and 73b can be mechanical vibration mechanisms. The pressing direction of the pressing portion is the direction perpendicular to the paper surface in FIG. 7.

Further, the vibration applied by the vibrating portions 73a and 73b can be unidirectional vibration on a surface parallel to the first both end surfaces, but it can also be configured so that the vibration direction can be switched. Also, it can be configured to give rotational vibration parallel to the first both end faces. In addition, in order to give vibration by the vibrating portions 73a and 73b, the pair of pressure plates 51 and 52 may also be arranged so as to vibrate in the same direction.

Further, although the switching of the vibration direction has been described in the description of the ultrasonic generator 53 and the vibration units 73a and 73b, this inspection method further includes a setting step of setting at least one value of the given vibration direction and frequency. Is preferable. In this case, the preparation step of step S1 prepares a state in which vibration based on the value set in the setting step is applied to the laminated body 30, and the inspection step of step S2 carries out the inspection in that state.

For that purpose, the inspection devices 50 and 70 are provided with a setting unit for setting at least one value of the frequency and direction of the vibration to be given, and the vibration unit transmits the vibration based on the value set in the setting unit to the laminated body 30. It may be configured so that it can be given.

In particular, the frequency of the given vibration can be set to the frequency of the vibration generated during the operation of the device equipped with the non-aqueous secondary battery 1 (for example, a typical frequency). As a result, it is possible to inspect a short circuit when the non-water secondary battery 1 is mounted on the device, and if a defective product containing a conductive foreign substance M is removed, the non-water secondary battery 1 is mounted on the device. It is possible to suppress the occurrence of defects in the battery 1.

By enabling such a setting, it is possible to set at least one of the device on which the non-aqueous secondary battery 1 is mounted and the stretching direction of the separator 42 whose tearability changes depending on the stretching direction at the time of manufacture. Therefore, by adopting such an inspection method, it is possible to inspect at least one of the non-aqueous secondary battery 1 and the device on which the non-aqueous secondary battery 1 is mounted for the presence or absence of a conductive foreign substance M that causes a defect. That is, in the inspection devices 50 and 70 having such a configuration, it is possible to perform an inspection corresponding to the non-aqueous secondary battery 1 in which the stretching directions of the separator 42 are various, and to perform an inspection in consideration of the mounting destination. Become.

For example, when a battery pack containing a non-aqueous secondary battery 1 is mounted on an automobile, which is an example of the above device, the vibration frequency to the battery pack is as high as about 50 Hz on a general rough road, and the vibration is the largest. Even on the expected road, it is as high as about 200 Hz. Therefore, the frequency at the time of inspection is preferably 5 to 200 Hz, more preferably 10 to 200 Hz, and can be, for example, 200 Hz, assuming that the battery pack is mounted on the automobile. As a result, the inspection can be performed with an accuracy that does not cause a problem when the vehicle is running. In this case, vibration can be applied by the vibrating units 73a and 73b. Further, the inspection is not limited to one frequency, and for example, the non-aqueous secondary battery 1 in which the inspection is carried out at all of a plurality of predetermined frequencies satisfying 10 Hz or more and 200 Hz or less and a conductive foreign substance is detected. By not mounting the battery as a defective product, it is possible to prevent a short circuit of the non-aqueous secondary battery 1 mounted on the automobile.

Next, an inspection example (test example) in this inspection method will be described with reference to FIG. FIG. 8 is a diagram showing the results of inspection by the main inspection method and the results of inspection by the inspection method according to the comparative example.

Regarding this inspection method, the inspection device 50 of FIG. 5 applies a vibration of 38 kHz from a direction parallel to the first end faces and a load (pressurization) of 0.4 kPa from the first end faces of 100 μm. As a result of inspecting the presence or absence of conductive foreign matter, conductive foreign matter could be detected. On the other hand, regarding the inspection method according to the comparative example, as a result of inspecting the presence or absence of a conductive foreign matter of 100 μm under a load of 1000 kPa from the first both end faces, no conductive foreign matter could be detected. In both this inspection method and the inspection method according to the comparative example, the inspection was carried out under the condition of 25 ° C. with the same stretching direction of the separator. Further, in this inspection method, the inspection was performed by applying vibration in the stretching direction.

As described above, the conductive foreign matter that could not be detected by the inspection method according to the comparative example could be detected by this inspection method, and could be detected with a significantly smaller load than the inspection method according to the comparative example. The fact that the load is small means that a low-cost pressing portion can be used and the power is also small. From this result, it can be said that the inspection method and the inspection apparatus according to the present embodiment can inspect the non-aqueous secondary battery 1 for the presence or absence of conductive foreign matter in a short time, with high accuracy, and at low cost. ..

(Other embodiments, etc.)
The present invention is not limited to the above-described embodiment, and each example included in the embodiment may be appropriately combined and implemented, and may be appropriately modified without departing from the spirit. Is. For example, the inspection device or inspection method described in the embodiment is not limited to the illustrated one, and may be any device that can function as an inspection device or a method capable of performing the above-mentioned inspection. Further, for example, the shape and material of each member of the secondary battery described in the embodiment, or the manufacturing method is not limited to the illustrated one, and the secondary battery can function as a secondary battery, or such a secondary battery. Any method can be used as long as the battery can be manufactured. Further, in the embodiment, a non-aqueous secondary battery is taken as an example, but the electrolytic solution is not limited to the non-aqueous electrolytic solution, and the secondary battery includes a laminate in which a positive electrode sheet, a separator, and a negative electrode sheet are laminated. If so, any secondary battery can be subject to inspection.

1 Non-aqueous secondary battery 10 Case 11 Lid 12 Negative electrode pole column 13 Positive electrode pole pillar 20 Laminated body 21, 41 Positive electrode sheet 21a Active material coating area on the positive electrode side 21b Tab part on the positive electrode side 22, 42 Separator 23, 43 Negative electrode sheet 23a Negative electrode side active material coating area 23b Negative electrode side tab part 30 Laminated body structure 32 Active material coating area 33 Positive electrode side active material uncoated area 34 Negative electrode side active material uncoated area 35 Draw-out electrode for positive electrode 36 Draw-out electrode for negative electrode 50, 70 Inspection device 51, 52 Pressurizing plate 53 Ultrasonic generator 54 Inspection part 73a, 73b Vibration part M Conductive foreign matter

Claims (12)

A state in which the electrolytic solution is not injected, which comprises a positive electrode sheet, a negative electrode sheet, a laminate having a separator sandwiched between the positive electrode sheet and the negative electrode sheet, and a case for accommodating the laminate. It is a secondary battery inspection method that inspects the secondary battery.
Both end faces perpendicular to the stacking direction of the laminate in the case are set as the first end faces.
A preparatory step of pressing the case from the first end faces and preparing a state in which the laminate is vibrated from a direction parallel to the first end faces.
In the above state, a voltage is applied to the secondary battery to inspect for the presence of conductive foreign matter, and an inspection step.
A secondary battery inspection method equipped with. The vibration includes vibration along the stretching direction when the separator is manufactured.
The secondary battery inspection method according to claim 1. The vibration is an ultrasonic vibration generated by an ultrasonic generator.
The secondary battery inspection method according to claim 1 or 2. The frequency of the vibration is the frequency of the vibration generated during the operation of the device equipped with the secondary battery.
The secondary battery inspection method according to any one of claims 1 to 3. A setting step for setting at least one value of the frequency and direction of the vibration is further provided.
The preparatory step prepares a state in which vibration based on the value set in the setting step is applied to the laminated body.
The secondary battery inspection method according to any one of claims 1 to 4. The laminated body is a laminated body having a wound body structure that is housed in the case in a state of being wound flat.
The stacking direction is the minor axis direction of the laminated body of the wound structure.
The secondary battery inspection method according to any one of claims 1 to 5. The laminated body is housed in the case with the positive electrode sheet, the separator, and the negative electrode sheet laminated in parallel.
The secondary battery inspection method according to any one of claims 1 to 5. A secondary sheet comprising a positive electrode sheet, a negative electrode sheet, a laminate having a separator sandwiched between the positive electrode sheet and the negative electrode sheet, and a case for accommodating the laminate, and in a state where no electrolytic solution is injected. A secondary battery inspection device that inspects batteries,
Both end faces perpendicular to the stacking direction of the laminate in the case are set as the first end faces.
A pressing portion that presses the case from the first both end surfaces, and
A vibrating portion that vibrates the laminated body from a direction parallel to the first both end faces,
An inspection unit that inspects the presence or absence of conductive foreign matter by applying a voltage to the secondary battery while pressing with the pressing unit and applying the vibration with the vibrating unit.
A secondary battery inspection device equipped with. The vibration includes vibration along the stretching direction when the separator is manufactured.
The secondary battery inspection device according to claim 8. A setting unit for setting at least one value of the frequency and direction of the vibration is provided.
The vibrating unit applies vibration based on the value set by the setting unit to the laminated body.
The secondary battery inspection device according to claim 8 or 9. The laminated body is a laminated body having a wound body structure that is housed in the case in a state of being wound flat.
The stacking direction is the minor axis direction of the laminated body of the wound structure.
The secondary battery inspection device according to any one of claims 8 to 10. The laminated body is housed in the case with the positive electrode sheet, the separator, and the negative electrode sheet laminated in parallel.
The secondary battery inspection device according to any one of claims 8 to 10.

Images