Patent Publication Number: US-2023142533-A1

Title: Insulation inspecting device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is the U.S. National Phase under 35 U.S.C. § 371 of International Patent Application No. PCT/JP2021/012560, filed on Mar. 25, 2021, which in turn claims the benefit of Japanese Patent Application No. 2020-062805, filed on Mar. 31, 2020, the entire content of each of which is incorporated herein by reference. 
    
    
     BACKGROUND 
     Field of the Invention 
     The present disclosure relates to an insulation inspection device. 
     Description of the Related Art 
     As batteries for automotive use or other applications, laminate-type batteries have been developed. Such a battery has a structure in which a container contains a laminated electrode group, in which multiple positive electrode plates and multiple negative electrode plates are alternately laminated with a separator in between, and also contains an electrolyte. To form a laminated electrode group, there is a method of forming, as a constituent unit of a laminated electrode group, a laminated electrode in which two electrode plates and two separators are alternately laminated, and sequentially laminating multiple laminated electrodes to complete a laminated electrode group. When forming a laminated electrode group by such a method, it is desirable to inspect the insulation of each laminated electrode before laminating it. 
     With regard to insulation inspection of laminated electrodes, Patent Literature 1, for example, discloses a method of laminating a positive electrode sheet and a negative electrode sheet via a separator sheet to form a sheet-like electrode laminate and applying a voltage between a pair of electrode rolls that sandwich the sheet-like electrode laminate, so as to measure the electric resistance value of the sheet-like electrode laminate. 
     Patent Literature 1: Japanese Unexamined Patent Application Publication No. 2009-170134 
     In the abovementioned conventional insulation inspection, a laminated electrode is provided between a pair of electrode rolls. Accordingly, insulation defects in the laminated electrode can be detected only when an insulation defect has occurred due to holes in both separators or when foreign matter mixed in an electrode plate is large enough to penetrate the two separators. In other words, it is difficult to detect insulation defects in the laminated electrode when an insulation defect has occurred only in one of the separators or when conductive foreign matter mixed in an electrode plate is small. Thus, there has been room for improving the performance of insulation inspection. Even if the foreign matter is too small to penetrate the two separators, it may be eluted in the electrolyte and may deposit on the electrode surface to grow in dendrite form, which may cause a short circuit. Therefore, it is desirable to also detect such small foreign matter as an insulation defect. 
     SUMMARY OF THE INVENTION 
     The present disclosure has been made in view of such a situation, and a purpose thereof is to provide a technology for improving the performance of insulation inspection for laminated electrodes. 
     One aspect of the present disclosure relates to an insulation inspection device. The device includes: a conveyance unit that conveys a laminated electrode in which a first separator, a first electrode plate, a second separator, and a second electrode plate are laminated in this order; a pressure roll that presses the laminated electrode against the conveyance unit; a first terminal electrically connected to the first electrode plate; a second terminal electrically connected to the second electrode plate, further electrically connected to the conveyance unit when the first separator is disposed on the conveyance unit side, and further electrically connected to the pressure roll when the first separator is disposed on the pressure roll side; and an insulation inspection unit that is connected to the first terminal and the second terminal and that applies a voltage to the laminated electrode to inspect insulation condition of the laminated electrode. 
     Optional combinations of the aforementioned constituting elements, and implementation of the present disclosure in the form of methods, apparatuses, or systems may also be practiced as additional modes of the present disclosure. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       Embodiments will now be described, by way of example only, with reference to the accompanying drawings which are meant to be exemplary, not limiting, and wherein like elements are numbered alike in several Figures, in which: 
         FIG.  1    is a schematic diagram of laminated electrode group manufacturing equipment that includes an insulation inspection device according to a first embodiment; 
         FIG.  2    is a perspective view of part of the insulation inspection device; 
         FIG.  3    is a sectional view of part of the insulation inspection device; 
         FIG.  4    is a diagram that shows relationships between the number of pressure rolls and a rotation angle of a conveyance unit in insulation inspection; 
         FIG.  5    is a sectional view of part of the insulation inspection device according to a second embodiment; 
         FIG.  6    is a perspective view of part of the insulation inspection device according to a third embodiment; and 
         FIG.  7    is a sectional view of part of the insulation inspection device according to a fourth embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following, the present disclosure will be described based on preferred embodiments with reference to the drawings. The embodiments are intended to be illustrative only and not to limit the present disclosure, so that it should be understood that not all of the features or combinations thereof described in the embodiments are necessarily essential to the present disclosure. Like reference characters denote like or corresponding constituting elements, members, and processes in each drawing, and repetitive description will be omitted as appropriate. 
     Also, the scale or shape of each component shown in each drawing is defined for the sake of convenience to facilitate the explanation and is not to be regarded as limitative unless otherwise specified. When the terms “first”, “second”, and the like are used in the present specification or claims, such terms do not imply any order or degree of importance and are used to distinguish one configuration from another, unless otherwise specified. Also, in each drawing, part of members less important in describing embodiments may be omitted. 
     First Embodiment 
       FIG.  1    is a schematic diagram of laminated electrode group manufacturing equipment that includes an insulation inspection device according to the first embodiment. As an example, laminated electrode group manufacturing equipment  1  is continuous drum-type manufacturing equipment in which multiple drums are combined. Performing each process of cutting, heating, bonding, laminating, and the like of electrode bodies and separators on the drums enables high-speed and continuous manufacturing of laminated electrodes and laminated electrode groups. The laminated electrode groups may be used, for example, for lithium-ion secondary batteries. 
     The laminated electrode group manufacturing equipment  1  includes a first electrode cutting drum  2 , a first electrode heating drum  4 , a second electrode cutting drum  6 , a second electrode heating drum  8 , a bonding drum  10 , an insulation inspection device  100 , a separator cutting drum  12 , and a laminating drum  14 . 
     The first electrode cutting drum  2  is a drum for cutting a continuous body of multiple first electrode plates into multiple individual first electrode plates and conveying the plates. In the present embodiment, the first electrode is a negative electrode. To the first electrode cutting drum  2 , a strip-shaped first electrode continuous body N as the continuous body of multiple first electrode plates is supplied. The first electrode continuous body N includes a first electrode current collector and a first electrode active material layer. The first electrode active material layer is laminated on both surfaces or one surface of the first electrode current collector. 
     Each of the first electrode current collector and the first electrode active material layer can be made of a publicly-known material and has a publicly-known structure. The first electrode current collector may be constituted by foil or a porous body made of copper, aluminum, or the like, for example. The first electrode active material layer may be formed by applying, onto a surface of the first electrode current collector, first electrode mixture slurry that contains a first electrode active material, such as graphite, and also contains a binder, a dispersant, and the like, and by drying and rolling the applied film. The thickness of the first electrode current collector may be in the range from 3 μm to 50 μm inclusive, for example. Also, the thickness of the first electrode active material layer may be in the range from 10 μm to 100 μm inclusive, for example. 
     The first electrode cutting drum  2  includes multiple holding heads arranged in a circumferential direction of the drum, and a cutting blade that cuts the first electrode continuous body N into multiple individual first electrode plates. Each of the multiple holding heads includes a holding surface that adsorbs and holds the first electrode continuous body N. The holding surface of each holding head faces outward from the first electrode cutting drum  2 . The first electrode continuous body N supplied to the first electrode cutting drum  2  is conveyed by the rotation of the first electrode cutting drum  2  while being adsorbed and held by the holding surfaces of the multiple holding heads. 
     Each of the multiple holding heads rotates around the central axis of the first electrode cutting drum  2  and can also move in a circumferential direction of the drum independently of other holding heads. Such independent driving of the holding heads enables adjustment of the positions of cutting by the cutting blade in the first electrode continuous body N and also enables adjustment of the positions of the individually divided first electrode plates, for example. The first electrode cutting drum  2  adsorbs and holds the supplied first electrode continuous body N and rotates to convey the first electrode continuous body N. At a cutting position  16  schematically illustrated in  FIG.  1   , the first electrode cutting drum  2  cuts the first electrode continuous body N to produce the first electrode plates. The first electrode continuous body N is cut by the cutting blade at a position between adjacent holding heads, so that multiple individual first electrode plates are obtained. Each first electrode plate thus obtained is conveyed while being adsorbed and held by each holding head. The positions of the multiple produced first electrode plates are monitored using a camera or the like. 
     The first electrode heating drum  4  is disposed in close proximity to the first electrode cutting drum  2 . Before the proximity position between the first electrode cutting drum  2  and the first electrode heating drum  4 , the speed of a holding head of the first electrode cutting drum  2  is temporarily increased or decreased until it becomes substantially identical with the linear velocity of the first electrode heating drum  4 . As a result, the relative speed of the holding head with respect to the first electrode heating drum  4  becomes substantially zero. At the timing when the relative speed becomes substantially zero, the holding head discharges, to the first electrode heating drum  4  side, the first electrode plate that the holding head has been adsorbing and holding. 
     The first electrode heating drum  4  rotates while adsorbing and holding the first electrode plates discharged from the first electrode cutting drum  2  and preheats the first electrode plates with a built-in heater. The preheating is performed to thermally bond a first electrode plate and a separator in the subsequent bonding process. Although the first electrode plates are heated at a heating position  18  in the present embodiment, the position is not limited thereto. For example, the first electrode plates may be heated in the entire circumferential area of the first electrode heating drum  4 . 
     The second electrode cutting drum  6  is a drum for cutting a continuous body of multiple second electrode plates into multiple individual second electrode plates and conveying the plates. In the present embodiment, the second electrode is a positive electrode. To the second electrode cutting drum  6 , a strip-shaped second electrode continuous body P as the continuous body of multiple second electrode plates is supplied. The second electrode continuous body P includes a second electrode current collector and a second electrode active material layer. The second electrode active material layer is laminated on both surfaces or one surface of the second electrode current collector. 
     Each of the second electrode current collector and the second electrode active material layer can be made of a publicly-known material and has a publicly-known structure. The second electrode current collector may be constituted by foil or a porous body made of stainless steel, aluminum, or the like, for example. The second electrode active material layer may be formed by applying, onto a surface of the second electrode current collector, second electrode mixture slurry that contains a second electrode active material, such as lithium cobalt oxide or lithium iron phosphate, and also contains a binder, a dispersant, and the like, and by drying and rolling the applied film. The thickness of the second electrode current collector may be in the range from 3 μm to 50 μm inclusive, for example. Also, the thickness of the second electrode active material layer may be in the range from 10 μm to 100 μm inclusive, for example. 
     The second electrode cutting drum  6  includes multiple holding heads arranged in a circumferential direction of the drum, and a cutting blade that cuts the second electrode continuous body P into multiple individual second electrode plates. Each of the multiple holding heads includes a holding surface that adsorbs and holds the second electrode continuous body P. The holding surface of each holding head faces outward from the second electrode cutting drum  6 . The second electrode continuous body P supplied to the second electrode cutting drum  6  is conveyed by the rotation of the second electrode cutting drum  6  while being adsorbed and held by the holding surfaces of the multiple holding heads. 
     Each of the multiple holding heads rotates around the central axis of the second electrode cutting drum  6  and can also move in a circumferential direction of the drum independently of other holding heads. Such independent driving of the holding heads enables adjustment of the positions of cutting by the cutting blade in the second electrode continuous body P and also enables adjustment of the positions of the individually divided second electrode plates, for example. The second electrode cutting drum  6  adsorbs and holds the supplied second electrode continuous body P and rotates to convey the second electrode continuous body P. At a cutting position  20  schematically illustrated in  FIG.  1   , the second electrode cutting drum  6  cuts the second electrode continuous body P to produce the second electrode plates. The second electrode continuous body P is cut by the cutting blade at a position between adjacent holding heads, so that multiple individual second electrode plates are obtained. Each second electrode plate thus obtained is conveyed while being adsorbed and held by each holding head. The positions of the multiple produced second electrode plates are monitored using a camera or the like. 
     The second electrode heating drum  8  is disposed in close proximity to the second electrode cutting drum  6 . Before the proximity position between the second electrode cutting drum  6  and the second electrode heating drum  8 , the speed of a holding head of the second electrode cutting drum  6  is temporarily increased or decreased until it becomes substantially identical with the linear velocity of the second electrode heating drum  8 . As a result, the relative speed of the holding head with respect to the second electrode heating drum  8  becomes substantially zero. At the timing when the relative speed becomes substantially zero, the holding head discharges, to the second electrode heating drum  8  side, the second electrode plate that the holding head has been adsorbing and holding. 
     The second electrode heating drum  8  rotates while adsorbing and holding the second electrode plates discharged from the second electrode cutting drum  6  and preheats the second electrode plates with a built-in heater. The preheating is performed to thermally bond a second electrode plate and a separator in the subsequent bonding process. Although the second electrode plates are heated at a heating position  22  in the present embodiment, the position is not limited thereto. For example, the second electrode plates may be heated in the entire circumferential area of the second electrode heating drum  8 . 
     The bonding drum  10  is a drum for forming a laminated electrode continuous body in which laminated electrodes, which each are constituted by a first separator, a first electrode plate, a second separator, and a second electrode plate, are continuously arranged. The bonding drum  10  is disposed in close proximity to the first electrode heating drum  4  and the second electrode heating drum  8 . To the bonding drum  10 , a strip-shaped first separator continuous body S 1 , in which multiple first separators are continuously arranged, and a strip-shaped second separator continuous body S 2 , in which multiple second separators are continuously arranged, are supplied. On a surface of each of the first separator continuous body S 1  and the second separator continuous body S 2 , a thermal bonding layer is provided. The thermal bonding layer has a property of developing no adhesiveness at room temperature but developing adhesiveness when heated. 
     Also, to the bonding drum  10 , multiple first electrode plates are supplied from the first electrode cutting drum  2  via the first electrode heating drum  4 , and multiple second electrode plates are supplied from the second electrode cutting drum  6  via the second electrode heating drum  8 . Each first electrode plate is rotationally conveyed while being preheated on the first electrode heating drum  4  and is discharged, to the bonding drum  10  side, at the proximity position between the first electrode heating drum  4  and the bonding drum  10 . Each second electrode plate is rotationally conveyed while being preheated on the second electrode heating drum  8  and is discharged, to the bonding drum  10  side, at the proximity position between the second electrode heating drum  8  and the bonding drum  10 . 
     The first separator continuous body S 1 , each first electrode plate, the second separator continuous body S 2 , and each second electrode plate are supplied to the bonding drum  10  at positions provided in the enumerated order from the upstream side of the rotational direction of the bonding drum  10 . Accordingly, the first separator continuous body S 1  is supplied to the bonding drum  10  first at a certain position. The first separator continuous body S 1  is adsorbed and held by the bonding drum  10  and rotationally conveyed. Subsequently, at a position on the downstream side of the supply position of the first separator continuous body S 1 , the first electrode plates are supplied from the first electrode heating drum  4  to the bonding drum  10  and placed on the first separator continuous body S 1 . The multiple first electrode plates are arranged on the first separator continuous body S 1  at predetermined intervals in the conveying direction of the first separator continuous body S 1 . 
     Subsequently, at a position on the downstream side of the supply position of the first electrode plates, the second separator continuous body S 2  is supplied to the bonding drum  10  and placed over the multiple first electrode plates. Thereafter, the first separator continuous body S 1 , multiple first electrode plates, and second separator continuous body S 2  are pressurized by a thermocompression bonding roller  24 , at a position on the downstream side of the supply position of the second separator continuous body S 2 . Accordingly, the first separator continuous body S 1 , each first electrode plate, and the second separator continuous body S 2  are bonded together. Subsequently, at a position on the downstream side of the position of pressure bonding by the thermocompression bonding roller  24 , the second electrode plates are supplied from the second electrode heating drum  8  to the bonding drum  10  and placed on the second separator continuous body S 2 . The multiple second electrode plates are arranged on the second separator continuous body S 2  at predetermined intervals in the conveying direction of the second separator continuous body S 2 . Also, the multiple second electrode plates are bonded to the second separator continuous body S 2  by the pressing force of the second electrode heating drum  8 . 
     Through the process described above, the first separator continuous body S 1 , multiple first electrode plates, second separator continuous body S 2 , and multiple second electrode plates are laminated in this order and bonded to each other, forming a laminated electrode continuous body  26 . The laminated electrode continuous body  26  has a structure in which the laminated electrodes, which each are constituted by a first separator, a first electrode plate, a second separator, and a second electrode plate, are continuously connected by the first separator continuous body S 1  and the second separator continuous body S 2 . By halting the supply of the second electrode plates from the second electrode cutting drum  6  side, three-layered laminated electrodes without the second electrode plates may be produced after every fixed number of pieces. The electrode plates of which supply is halted may also be the first electrode plates. 
     The laminated electrode continuous body  26  is conveyed from the bonding drum  10  to the insulation inspection device  100 . In the insulation inspection device  100 , the insulation condition of each laminated electrode is inspected. The structure of the insulation inspection device  100  will be detailed later. The laminated electrode continuous body  26  that has passed through the insulation inspection device  100  is conveyed to the separator cutting drum  12 . 
     The separator cutting drum  12  is a drum for cutting the first separator continuous body S 1  and the second separator continuous body S 2  in the laminated electrode continuous body  26  to obtain multiple individual laminated electrodes. The separator cutting drum  12  includes multiple holding heads arranged in a circumferential direction of the drum, and a cutting blade that cuts the laminated electrode continuous body  26  into multiple individual laminated electrodes. Each of the multiple holding heads includes a holding surface that adsorbs and holds the laminated electrode continuous body  26 . The holding surface of each holding head faces outward from the separator cutting drum  12 . The laminated electrode continuous body  26  supplied to the separator cutting drum  12  is conveyed by the rotation of the separator cutting drum  12  while being adsorbed and held by the holding surfaces of the multiple holding heads. 
     Each of the multiple holding heads rotates around the central axis of the separator cutting drum  12  and may also be movable in a circumferential direction of the drum independently of other holding heads. Such independent driving of the holding heads enables adjustment of the positions of cutting by the cutting blade in the laminated electrode continuous body  26  and also enables adjustment of the positions of the individually divided laminated electrodes, for example. 
     The separator cutting drum  12  adsorbs and holds the supplied laminated electrode continuous body  26  and rotates to convey the laminated electrode continuous body  26 . At a cutting position  28  schematically illustrated in  FIG.  1   , the separator cutting drum  12  cuts the laminated electrode continuous body  26 . The laminated electrode continuous body  26  is cut by the cutting blade at a position between adjacent holding heads, so that multiple individual laminated electrodes are obtained. At the time, in the laminated electrode continuous body  26 , the first separator continuous body S 1  and the second separator continuous body S 2  are cut at a position between electrode plates that are adjacent in the conveying direction of the laminated electrode continuous body  26 . Each laminated electrode thus obtained is conveyed while being adsorbed and held by each holding head. A holding head discharges, to the laminating drum  14  side, a laminated electrode that the holding head has been adsorbing and holding. The positions of the multiple produced laminated electrodes are monitored using a camera or the like. 
     The laminating drum  14  is a drum for laminating multiple laminated electrodes on a lamination stage  30  to form a laminated electrode group. The laminating drum  14  includes multiple laminating heads arranged in a circumferential direction of the drum. Each laminating head includes a holding surface that adsorbs and holds a laminated electrode. The holding surface of each laminating head faces outward from the laminating drum  14 . Each of the multiple laminating heads rotates around the central axis of the laminating drum  14  and can also move in a circumferential direction of the drum independently of other laminating heads. With such independent driving of the laminating heads, while the rotation of the laminating drum  14  can be maintained at a constant angular velocity, each laminating head can be placed in a stop state at a laminating position facing the lamination stage  30 . By placing a laminating head in the stop state at a position facing the lamination stage  30 , the laminated electrode adsorbed and held by the laminating head can be discharged onto the lamination stage  30  with high positional accuracy. 
     The lamination stage  30  is disposed immediately beneath the laminating drum  14 . On the lamination stage  30 , the laminated electrodes discharged from the laminating drum  14  are sequentially laminated. Thus, a laminated electrode group is formed. The lamination stage  30  can be driven in an X-axis direction and a Y-axis direction perpendicular to each other. Also, a tilt angle on an X-Y plane of the lamination stage  30  can be adjusted. This enables adjustment of the positions in the X-axis direction and the Y-axis direction and the tilt angle of a laminated electrode discharged from the laminating drum  14 , with respect to a laminated electrode already laminated on the lamination stage  30 . 
     In the following, the insulation inspection device  100  will be described in detail.  FIG.  2    is a perspective view of part of the insulation inspection device  100 .  FIG.  3    is a sectional view of part of the insulation inspection device  100 . In  FIG.  2   , illustration of the circuit structure of an insulation inspection unit is omitted. Also, in  FIG.  3   , a conveyance unit  102  is schematically illustrated. Further, in  FIGS.  2  and  3   , a single laminated electrode  32  is illustrated for the convenience of illustration. 
     The insulation inspection device  100  includes a conveyance unit  102 , a pressure roll  104 , a first terminal  106 , a second terminal  108 , and an insulation inspection unit  110 . The conveyance unit  102  is a mechanism for conveying the laminated electrodes  32 . In the present embodiment, the conveyance unit  102  is constituted by a conveyance roll. The conveyance unit  102  includes a holding surface  102   a  that holds a laminated electrode  32 . The holding surface  102   a  is provided over the entire circumference of the conveyance roll. Each laminated electrode  32  has a structure in which a first separator  34 , a first electrode plate  36 , a second separator  38 , and a second electrode plate  40  are laminated in this order. In the present embodiment, a laminated electrode  32  is placed on the holding surface  102   a  such that the first separator  34  faces the conveyance unit  102  side. Therefore, the first separator  34  and the holding surface  102   a  are in contact with each other. 
     The pressure roll  104  is a mechanism for pressing a laminated electrode  32  against the conveyance unit  102 . The pressure roll  104  is disposed to face the holding surface  102   a  with a certain space in between and rotates as the laminated electrode  32  is conveyed. The laminated electrode  32  is conveyed by the conveyance unit  102  and passes through the gap between the conveyance unit  102  and the pressure roll  104 . The laminated electrode  32  is pressed against the holding surface  102   a  by the pressure roll  104  sequentially from the upstream side in the conveyance direction. The pressure roll  104  comes into contact with the second electrode plate  40 . The linear pressure of the pressure roll  104  is about 2 N/cm, for example. 
     The first terminal  106  is electrically connected to the first electrode plate  36 . The first electrode plate  36  includes a tab part  36   a  for current collection protruding from one side of the electrode plate extending in the conveyance direction of the laminated electrodes  32 . The tab part  36   a  protrudes from a partial area of the one side. When viewed from the laminating direction of the separators and the electrode plates, the tab part  36   a  protrudes to the outside of the first separator  34  and the second separator  38 . The first terminal  106  comes into contact with the tab part  36   a  to be electrically connected to the first electrode plate  36 . 
     The second terminal  108  is electrically connected to the second electrode plate  40 . The second electrode plate  40  includes a tab part  40   a  for current collection protruding from one side of the electrode plate extending in the conveyance direction of the laminated electrodes  32 . The tab part  40   a  protrudes from a partial area of the one side. Also, the tab part  40   a  is disposed on the same side as the tab part  36   a.  When viewed from the laminating direction of the separators and the electrode plates, the tab part  40   a  protrudes to the outside of the first separator  34  and the second separator  38 . The second terminal  108  comes into contact with the tab part  40   a  to be electrically connected to the second electrode plate  40 . 
     The first terminal  106  and the second terminal  108  of the present embodiment are provided on the holding surface  102   a.  On the holding surface  102   a,  multiple terminal pairs, which each are constituted by one first terminal  106  and one second terminal  108 , are arranged at predetermined intervals in the conveyance direction of the laminated electrodes  32 . The interval between adjacent terminal pairs corresponds to the interval between adjacent two laminated electrodes  32  in the laminated electrode continuous body  26 . Also, the interval between the first terminal  106  and the second terminal  108  in each pair corresponds to the interval between the tab part  36   a  and the tab part  40   a  in each laminated electrode  32 . 
     Accordingly, when the laminated electrode continuous body  26  is held by the holding surface  102   a,  the tab part  36   a  of each laminated electrode  32  can be brought into contact with the first terminal  106 , and the tab part  40   a  thereof can be brought into contact with the second terminal  108 . Therefore, by simply placing the laminated electrode continuous body  26  on the holding surface  102   a,  both the electrical connection between the first electrode plate  36  and the first terminal  106  and the electrical connection between the second electrode plate  40  and the second terminal  108  can be accomplished. 
     Each of the first terminal  106  and the second terminal  108  has a planar shape. Since each laminated electrode  32  is oriented such that the first separator  34  comes into contact with the holding surface  102   a,  the tab part  40   a  is located farther from the holding surface  102   a  than the tab part  36   a.  Accordingly, the thickness of the second terminal  108  is set greater than the thickness of the first terminal  106 . Therefore, when a laminated electrode  32  is placed on the holding surface  102   a,  the first terminal  106  and the second terminal  108  can be respectively brought into contact with the tab part  36   a  and the tab part  40   a  more certainly. 
     The first terminal  106  is electrically insulated from the conveyance unit  102 . Meanwhile, the second terminal  108  is electrically connected to the conveyance unit  102 . In the conveyance unit  102 , at least holding surface  102   a  is made of a conductive material such as metal. The first terminal  106  is fixed to the holding surface  102   a  via an insulating sheet or insulating adhesive, which is not illustrated. Therefore, the first terminal  106  is electrically insulated from the conveyance unit  102 . Meanwhile, the second terminal  108  is fixed to the holding surface  102   a  directly or via a conductive adhesive or the like. Therefore, the second terminal  108  is electrically connected to the conveyance unit  102 . 
     Accordingly, the tab part  36   a  is electrically insulated from the conveyance unit  102 . Meanwhile, the tab part  40   a  is electrically connected to the conveyance unit  102  via the second terminal  108 . Also, the first terminal  106  is not connected to the second electrode plate  40 , and the second terminal  108  is not connected to the first electrode plate  36 . Therefore, if there is no insulation defect in the laminated electrode  32 , the first terminal  106  is electrically insulated from the second electrode plate  40 , and the second terminal  108  is electrically insulated from the first electrode plate  36 . 
     The insulation inspection unit  110  inspects the insulation condition of each laminated electrode  32 . As an example, the insulation inspection unit  110  includes a resistance measurement unit  111  and a judgment unit  112 . The resistance measurement unit  111  may be constituted by a publicly-known insulation resistance tester, for example, and includes a power supply  114 , an ammeter  116 , and a voltmeter  118 . The power supply  114  is connected to the first terminal  106  and the second terminal  108  to apply a voltage to a laminated electrode  32 . The ammeter  116  is inserted in series in the wire that connects the power supply  114  and the second terminal  108 . The voltmeter  118  is connected to the wire that connects the power supply  114  and the first terminal  106  and also to the wire that connects the power supply  114  and the second terminal  108 . 
     The resistance measurement unit  111  applies a voltage from the power supply  114  to a laminated electrode  32  to measure, with the ammeter  116 , a leakage current generated in the laminated electrode  32  and also measure, with the voltmeter  118 , the voltage at the time. The resistance measurement unit  111  calculates the insulation resistance value of the laminated electrode  32  by dividing the measured voltage by the measured current. The resistance measurement unit  111  then transmits a signal indicating the insulation resistance value thus obtained to the judgment unit  112 . 
     The judgment unit  112  judges the insulation condition of the laminated electrode  32  based on the measurement results from the resistance measurement unit  111 . The judgment unit  112  may be implemented by an element such as a CPU or memory of a computer or by a circuit as a hardware configuration, and by a computer program or the like as a software configuration.  FIG.  3    illustrates a functional block implemented by cooperation of such components. It will be naturally understood by those skilled in the art that the functional block may be implemented in a variety of forms by combinations of hardware and software. 
     For example, the judgment unit  112  may retain a threshold of the insulation resistance value in advance and judge, when the insulation resistance value of a laminated electrode  32  falls below the threshold, that the laminated electrode  32  has an insulation defect. Also, the judgment unit  112  may acquire the voltage value and the current value from the resistance measurement unit  111  to calculate the insulation resistance value of the laminated electrode  32 . Further, the insulation inspection unit  110  may measure the current value while the voltage applied to the laminated electrode  32  is kept constant; based on the change in the current value, the insulation inspection unit  110  may judge an insulation defect of the laminated electrode  32 . 
     When the first separator  34  has a through hole or the like or when there is conductive foreign matter that conducts electricity between the first electrode plate  36  and the holding surface  102   a,  a closed circuit including the power supply  114 , the first terminal  106 , the first electrode plate  36 , the conveyance unit  102 , and the second terminal  108  is formed, so that a current flows therein. Also, when the second separator  38  has a through hole or the like or when there is conductive foreign matter that conducts electricity between the first electrode plate  36  and the second electrode plate  40 , a closed circuit including the power supply  114 , the first terminal  106 , the first electrode plate  36 , the second electrode plate  40 , and the second terminal  108  is formed, so that a current flows therein. 
     Therefore, according to the present embodiment, even when only one of the first separator  34  or the second separator  38  has an insulation defect or when foreign matter mixed in the first electrode plate  36  or the second electrode plate  40  is not large enough to penetrate the two separators, an insulation defect in the laminated electrode  32  can be detected. 
     The insulation inspection unit  110  can inspect the insulation condition of a region of a laminated electrode  32  pressed by the pressure roll  104 . When a laminated electrode  32  is pressed by the pressure roll  104 , the thicknesses of the first separator  34  and the second separator  38  decrease, and the distance between the holding surface  102   a  and the first electrode plate  36  and the distance between the first electrode plate  36  and the second electrode plate  40  become smaller. Accordingly, when a short circuit occurs between the holding surface  102   a  and the first electrode plate  36  or between the first electrode plate  36  and the second electrode plate  40  at the position pressed by the pressure roll  104  and a closed circuit is formed, an insulation defect is detected. The laminated electrode  32  is pressed by the pressure roll  104  sequentially from the upstream side toward the downstream side in the conveyance direction while being conveyed by the conveyance unit  102  and, when the laminated electrode  32  has passed through the gap between the conveyance unit  102  and the pressure roll  104 , the insulation inspection of the entire laminated electrode  32  is completed. 
     The insulation inspection device  100  is preferably equipped with multiple pressure rolls  104  arranged in the conveyance direction of the laminated electrodes  32 . The insulation inspection device  100  of the present embodiment includes two pressure rolls  104 . The insulation inspection of a laminated electrode  32  is performed during a period from when the front end of the laminated electrode  32  reaches the most downstream pressure roll  104  in the conveyance direction of the laminated electrode  32  until the rear end of the laminated electrode  32  reaches the most upstream pressure roll  104 . Accordingly, with multiple pressure rolls  104  provided, an area of the laminated electrode  32  pressurized by each pressure roll  104  during the insulation inspection can be made smaller. In other words, the area pressed by the pressure rolls  104  at one time in the laminated electrode  32  can be increased. This can reduce the rotation angle of the conveyance unit  102  required for the insulation inspection. Therefore, the time required for the insulation inspection can be shortened. 
       FIG.  4    is a diagram that shows relationships between the number of pressure rolls  104  and the rotation angle of the conveyance unit  102  in insulation inspection. The insulation resistance value of each laminated electrode  32  cannot be measured unless the laminated electrode  32  is charged. Accordingly, the conduction of current from the power supply  114  to a laminated electrode  32  needs to be started before the laminated electrode  32  is pressurized by the most downstream pressure roll  104 . Therefore, the insulation inspection is started when the current conduction to the laminated electrode  32  is started. 
     The start timing of insulation inspection is determined based on the positional relationship between the laminated electrode  32  and each pressure roll  104 , which is calculated from the conveying speed of the laminated electrode  32  and the time required to charge the laminated electrode  32 . The conveying speed of the laminated electrode  32  may be 65 m/min, for example, and the time required to charge the laminated electrode  32  may be about 10 ms, for example. As shown in  FIG.  4   , when the 12 o&#39;clock position of the conveyance roll is defined as the reference (0 degrees) and when one pressure roll  104  is provided at the 0-degree position, the start timing of the insulation inspection is when the front end of the laminated electrode  32  is located at the −4-degree position. Also, when two pressure rolls  104  are provided at the ±17-degree positions, the start timing is when the front end of the laminated electrode  32  is located at the 12-degree position. Also, when three pressure rolls  104  are provided at the 0-degree position and the ±26-degree positions, the start timing is when the front end of the laminated electrode  32  is located at the 22-degree position. 
     At the same time as the charging of the laminated electrode  32  is completed, the front end of the laminated electrode  32  reaches the pressure roll  104  on the most downstream side, and the pressurization to the laminated electrode  32  by the pressure roll  104  starts. From this point until the rear end of the laminated electrode  32  reaches the most upstream pressure roll  104 , the resistance value of the laminated electrode  32  is measured (during inspection). When the rear end of the laminated electrode  32  reaches the most upstream pressure roll  104 , pressurization to the entire area of the laminated electrode  32 , i.e., the measurement of the resistance value, is completed. At the timing, the current conduction to the laminated electrode  32  is also stopped. 
     If the voltage remains in the laminated electrode  32 , sparks due to a short circuit may occur on the downstream side of the insulation inspection device  100 , for example. Accordingly, it is preferable that the conveyance unit  102  holds the laminated electrode  32  until the discharge of the laminated electrode  32  is completed. Therefore, the insulation inspection of the laminated electrode  32  is terminated when the discharge of the laminated electrode  32  is completed. The time required from the stop of current conduction to the completion of discharge is about 10 ms, for example. 
     As shown in  FIG.  4   , when one pressure roll  104  is provided, the end timing of the insulation inspection is when the front end of the laminated electrode  32  is located at the 90-degree position. Also, when two pressure rolls  104  are provided, the end timing is when the front end of the laminated electrode  32  is located at the 74-degree position. Also, when three pressure rolls  104  are provided, the end timing is when the front end of the laminated electrode  32  is located at the 63-degree position. Therefore, when one pressure roll  104  is provided, the rotation angle required for the insulation inspection is 94 degrees; when two pressure rolls  104  are provided, the required rotation angle is 62 degrees; and when three pressure rolls  104  are provided, the required rotation angle is 41 degrees. 
     From the above results, it is understood that, by providing multiple pressure rolls  104 , the time required for the insulation inspection can be shortened. The arrangement of each pressure roll  104  on the conveyance unit  102  is not limited to that shown in  FIG.  4   . Also, four or more pressure rolls  104  may be provided. However, as the number of pressure rolls  104  increases, the disadvantages of increased cost due to the increased number of pressure rolls  104  and the like become likely to outweigh the advantages of reduced inspection time and the like. Therefore, the number of pressure rolls  104  may preferably be three or fewer. 
     As described above, the insulation inspection device  100  according to the present embodiment includes: the conveyance unit  102  that conveys a laminated electrode  32  in which the first separator  34 , the first electrode plate  36 , the second separator  38 , and the second electrode plate  40  are laminated in this order, in which the first separator  34  is disposed on the conveyance unit  102  side; the pressure roll  104  that presses the laminated electrode  32  against the conveyance unit  102 ; the first terminal  106  electrically connected to the first electrode plate  36 ; the second terminal  108  electrically connected to the second electrode plate  40  and the conveyance unit  102 ; and the insulation inspection unit  110  that is connected to the first terminal  106  and the second terminal  108  and that applies a voltage to the laminated electrode  32  to inspect insulation condition of the laminated electrode  32 . 
     Accordingly, even when only one of the first separator  34  or the first electrode plate  36  has an insulation defect, insulation defects in the laminated electrode  32  can be detected. Also, compared to the case where the insulation condition of the laminated electrode  32  is inspected with a pair of electrodes sandwiching the laminated electrode  32  from both outsides, an insulation defect caused by smaller foreign matter can be detected. Therefore, the performance of insulation inspection for the laminated electrodes  32  can be improved. 
     Also, the insulation inspection device  100  of the present embodiment enables in-line insulation inspection. Accordingly, it can be prevented that the production lead time of the laminated electrode groups is increased by the insulation inspection of the laminated electrodes  32 . Also, the insulation inspection device  100  of the present embodiment includes multiple pressure rolls  104  arranged in the conveyance direction of the laminated electrodes  32 . This can reduce the time required for the insulation inspection of the laminated electrodes  32 . Therefore, it can be prevented that the conveying speed of the laminated electrodes  32  is decreased because the insulation inspection device  100  is provided on the conveyance line. 
     Also, the conveyance unit  102  includes the holding surface  102   a  that holds a laminated electrode  32 , and the first terminal  106  and the second terminal  108  are provided on the holding surface  102   a.  Accordingly, at the same time as a laminated electrode  32  is placed on the holding surface  102   a,  each electrode plate and a corresponding terminal can be electrically connected. Also, each terminal follows the movement of the laminated electrode  32 . Therefore, the electrical connection between each electrode plate and a corresponding terminal can be maintained with a simpler structure. 
     Second Embodiment 
     The second embodiment includes configurations in common with the first embodiment, except for the orientation of the laminated electrode  32  placed on the conveyance unit  102  and the structure of the insulation inspection device  100 . In the following, the present embodiment will be described mainly for configurations different from those in the first embodiment, and description of configurations in common will be briefly given or may be omitted.  FIG.  5    is a sectional view of part of the insulation inspection device  100  according to the second embodiment. In  FIG.  5   , the conveyance unit  102  is schematically illustrated. Also, for the convenience of illustration, a single laminated electrode  32  is illustrated. 
     The insulation inspection device  100  includes the conveyance unit  102 , the pressure roll  104 , the first terminal  106 , the second terminal  108 , and the insulation inspection unit  110 . The conveyance unit  102  includes the holding surface  102   a.  In the present embodiment, a laminated electrode  32  is placed on the holding surface  102   a  such that the second electrode plate  40  faces the conveyance unit  102  side. The pressure roll  104  presses the laminated electrode  32  against the conveyance unit  102 . The pressure roll  104  comes into contact with the first separator  34  and presses the laminated electrode  32  against the holding surface  102   a.  Thus, the laminated electrode  32  is conveyed in a state where the first separator  34  is disposed on the pressure roll  104  side. The pressure roll  104  is constituted by an electric conductor such as metal. 
     The first terminal  106  is electrically connected to the first electrode plate  36 . The first terminal  106  comes into contact with the tab part  36   a  to be electrically connected to the first electrode plate  36 . The second terminal  108  is electrically connected to the second electrode plate  40 . The second terminal  108  comes into contact with the tab part  40   a  to be electrically connected to the second electrode plate  40 . Also, the first terminal  106  is electrically insulated from the pressure roll  104 . Meanwhile, the second terminal  108  is electrically connected to the pressure roll  104 . 
     For example, the first terminal  106  is fixed to the holding surface  102   a  via an insulating sheet or insulating adhesive, not illustrated, and connected to the tab part  36   a.  Also, the second terminal  108  is divided into multiple portions, and some of the portions are fixed to the holding surface  102   a  via an insulating sheet or insulating adhesive, not illustrated, and connected to the tab part  40   a.  Some other portions are electrically connected to the pressure roll  104 . Accordingly, the tab part  36   a  and the tab part  40   a  are electrically insulated from the conveyance unit  102 . Also, the first terminal  106  is not connected to the second electrode plate  40 , and the second terminal  108  is not connected to the first electrode plate  36 . 
     As an example, the insulation inspection unit  110  includes the resistance measurement unit  111  and the judgment unit  112 . The resistance measurement unit  111  includes the power supply  114 , the ammeter  116 , and the voltmeter  118 . The resistance measurement unit  111  applies a voltage from the power supply  114  to a laminated electrode  32  to measure the insulation resistance value of the laminated electrode  32  and transmits a signal indicating the measurement result to the judgment unit  112 . The judgment unit  112  judges that the laminated electrode  32  has an insulation defect. 
     When the first separator  34  has a through hole or the like or when there is foreign matter that conducts electricity between the first electrode plate  36  and the pressure roll  104 , a closed circuit including the power supply  114 , the first terminal  106 , the first electrode plate  36 , the pressure roll  104 , and the second terminal  108  is formed, so that a current flows therein. Also, when the second separator  38  has a through hole or the like or when there is foreign matter that conducts electricity between the first electrode plate  36  and the second electrode plate  40 , a closed circuit including the power supply  114 , the first terminal  106 , the first electrode plate  36 , the second electrode plate  40 , and the second terminal  108  is formed, so that a current flows therein. 
     Thus, also according to the present embodiment, even when only one of the first separator  34  or the second separator  38  has an insulation defect or when foreign matter mixed in the first electrode plate  36  or the second electrode plate  40  is not large enough to penetrate the two separators, an insulation defect in the laminated electrode  32  can be detected, as is the case in the first embodiment. Therefore, the performance of insulation inspection for the laminated electrodes  32  can be improved. 
     Third Embodiment 
     The third embodiment includes configurations in common with the first embodiment, except for the structures of the laminated electrodes  32  and the insulation inspection device  100 . In the following, the present embodiment will be described mainly for configurations different from those in the first embodiment, and description of configurations in common will be briefly given or may be omitted.  FIG.  6    is a perspective view of part of the insulation inspection device  100  according to the third embodiment. In  FIG.  6   , illustration of the circuit structure of the insulation inspection unit  110  is omitted. Also, for the convenience of illustration, a single laminated electrode  32  is illustrated. 
     Each laminated electrode  32  of the present embodiment has a structure in which the first separator  34 , the first electrode plate  36 , the second separator  38 , and the second electrode plate  40  are laminated in this order. 
     The first electrode plate  36  includes the tab part  36   a  protruding from one side of the electrode plate extending in the conveyance direction of the laminated electrodes  32 . The tab part  36   a  in the present embodiment protrudes from the entire area of the one side. The second electrode plate  40  includes the tab part  40   a  protruding from one side of the electrode plate extending in the conveyance direction of the laminated electrodes  32 . The tab part  40   a  protrudes from the entire area of the one side. Also, the tab part  40   a  is disposed on the opposite side from the tab part  36   a.    
     The insulation inspection device  100  includes the conveyance unit  102 , the pressure roll  104 , the first terminal  106 , the second terminal  108 , and the insulation inspection unit  110 . The conveyance unit  102  includes the holding surface  102   a.  A laminated electrode  32  is placed on the holding surface  102   a  such that the first separator  34  faces the conveyance unit  102  side. The pressure roll  104  presses the laminated electrode  32  against the conveyance unit  102 . The pressure roll  104  comes into contact with the second electrode plate  40  and presses the laminated electrode  32  against the holding surface  102   a.    
     The first terminal  106  of the present embodiment is constituted by a probe with a roll at the tip. The roll of the first terminal  106  comes into contact with the tab part  36   a.  The roll rotates as the laminated electrode  32  is conveyed, so as to maintain the electrical connection with the tab part  36   a.  Since an insulation member intervenes between the tab part  36   a  and the holding surface  102   a,  the tab part  36   a  is electrically insulated from the holding surface  102   a.    
     The second terminal  108  of the present embodiment is constituted by a probe with a roll at the tip. The roll of the second terminal  108  comes into contact with the tab part  40   a.  The roll rotates as the laminated electrode  32  is conveyed, so as to maintain the electrical connection with the tab part  40   a.  Also, the tab part  40   a  is pressed against the holding surface  102   a  by the second terminal  108 , so as to be electrically connected to the conveyance unit  102 . Accordingly, the second terminal  108  is electrically connected to the holding surface  102   a  via the tab part  40   a.  The second terminal  108  may also be electrically connected to the holding surface  102   a  without the intervention of the tab part  40   a.  The first terminal  106  is not connected to the second electrode plate  40 , and the second terminal  108  is not connected to the first electrode plate  36 . 
     Thus, the configuration set forth above also provides the same effects as the first embodiment. Also in the present embodiment, the laminated electrode  32  may be placed on the holding surface  102   a  such that the second electrode plate  40  faces the conveyance unit  102  side, as is the case in the second embodiment. 
     Fourth Embodiment 
     The fourth embodiment includes configurations in common with the first embodiment, except for the structure of the insulation inspection device  100 . In the following, the present embodiment will be described mainly for configurations different from those in the first embodiment, and description of configurations in common will be briefly given or may be omitted.  FIG.  7    is a sectional view of part of the insulation inspection device  100  according to the fourth embodiment. In  FIG.  7   , the conveyance unit  102  is schematically illustrated. Also, for the convenience of illustration, a single laminated electrode  32  is illustrated. 
     The insulation inspection device  100  includes the conveyance unit  102 , the pressure roll  104 , the first terminal  106 , the second terminal  108 , and the insulation inspection unit  110 . The conveyance unit  102  includes the holding surface  102   a.  A laminated electrode  32  is placed on the holding surface  102   a  such that the first separator  34  faces the conveyance unit  102  side. The pressure roll  104  presses the laminated electrode  32  against the conveyance unit  102 . The pressure roll  104  comes into contact with the second electrode plate  40  and presses the laminated electrode  32  against the holding surface  102   a.    
     The first terminal  106  comes into contact with the tab part  36   a  to be electrically connected to the first electrode plate  36 . The second terminal  108  comes into contact with the tab part  40   a  to be electrically connected to the second electrode plate  40 . Also, the first terminal  106  is electrically insulated from the conveyance unit  102 . Meanwhile, the second terminal  108  is electrically connected to the conveyance unit  102 . Also, the first terminal  106  is not connected to the second electrode plate  40 , and the second terminal  108  is not connected to the first electrode plate  36 . 
     The insulation inspection unit  110  includes the resistance measurement unit  111 , the judgment unit  112 , and a waveform measurement unit  120 . The resistance measurement unit  111  includes the power supply  114 , the ammeter  116 , and the voltmeter  118 . The resistance measurement unit  111  applies a voltage from the power supply  114  to a laminated electrode  32  to measure the insulation resistance value of the laminated electrode  32 . The resistance measurement unit  111  then transmits a signal indicating the measurement result to the judgment unit  112 . 
     The waveform measurement unit  120  measures the waveform of a current or voltage generated when a voltage is applied to the laminated electrode  32 . The waveform measurement unit  120  is constituted by a publicly-known pulse meter, for example. The insulation inspection unit  110  includes a resistor  122  inserted in series in the wire that connects the power supply  114  and the first terminal  106 , and the waveform measurement unit  120  is connected in parallel to the resistor  122 . With the waveform measurement unit  120 , spike-like waveforms of a current or a voltage or both generated when the laminated electrode  32  is pressurized by the pressure roll  104  can be detected. Such a spike-like waveform is generated when conductive foreign matter is pressed by the pressure roll  104 , for example. The waveform measurement unit  120  then transmits a signal indicating the measurement result to the judgment unit  112 . 
     The judgment unit  112  judges the insulation condition of the laminated electrode  32  based on the measurement results from the resistance measurement unit  111  and the waveform measurement unit  120 . For example, when the insulation resistance value of the laminated electrode  32  falls below a threshold or when a waveform is measured by the waveform measurement unit  120 , the judgment unit  112  judges that the laminated electrode  32  has an insulation defect. When insulation inspection is performed by pressing a laminated electrode  32  with the pressure roll  104 , only a portion pressed by the pressure roll  104  is assumed to be locally short-circuited. In this case, the measured insulation resistance value corresponds to an average of the resistance value of the portion pressed by the pressure roll  104  and the resistance value of the portion that is not pressed. Accordingly, if the decrease in the resistance value of the portion pressed by the pressure roll  104  is small, it may not be judged as an insulation defect. In contrast, by detecting, with the waveform measurement unit  120 , a leakage waveform of a current or a voltage generated when the pressure roll  104  passes, even a slight decrease in the resistance value caused by foreign matter of small diameter or the like can be judged as an insulation defect in the laminated electrode  32 . 
     Therefore, according to the present embodiment, the performance of insulation inspection for the laminated electrodes  32  can be further improved. The judgment unit  112  may judge an insulation defect in a laminated electrode  32  only based on the measurement result from the waveform measurement unit  120 . Also in the present embodiment, the laminated electrode  32  may be placed on the holding surface  102   a  such that the second electrode plate  40  faces the conveyance unit  102  side, as is the case in the second embodiment. 
     Embodiments of the present disclosure have been described in detail. The abovementioned embodiments merely describe specific examples for carrying out the present disclosure. The embodiments are not intended to limit the technical scope of the present disclosure, and various design modifications, including changes, addition, and deletion of constituting elements, may be made to the embodiments without departing from the scope of ideas of the present disclosure defined in the claims. Such an additional embodiment with a design modification added has the effect of each of the combined embodiments and modifications. In the aforementioned embodiments, matters to which design modifications may be made are emphasized with the expression of “of the present embodiment”, “in the present embodiment”, or the like. However, design modifications may also be made to matters without such expression. Optional combinations of the abovementioned constituting elements may also be employed as additional modes of the present disclosure. Also, the hatching provided on the cross sections in the drawings does not limit the materials of the objects with the hatching. 
     The insulation inspection device  100  can also inspect insulation of the laminated electrodes  32  in the form of a laminated electrode continuous body  26  and can also inspect insulation of the laminated electrodes  32  separated individually. Therefore, the insulation inspection device  100  may also be disposed between the separator cutting drum  12  and the laminating drum  14 . 
     The laminated electrode group manufacturing equipment  1  need not necessarily be a continuous drum type. Also, the insulation inspection device  100  is not limited to a roll type. The conveyance unit  102  may be a planar conveyance stage, instead of a conveyance roll. Also, the insulation inspection unit  110  may include only the resistance measurement unit  111  or the waveform measurement unit  120  or both, and a user may directly monitor the measurement results. Also, the judgment unit  112  may be provided in an external device, such as an external computer.