JP2022176622A - Method for inspecting member for battery, method for manufacturing member for battery, and method for manufacturing battery pack - Google Patents

Abstract

To provide a method for inspecting a member for a battery that can easily discover a malfunction such as a short-circuit and contribute to an improvement in manufacturing efficiency.SOLUTION: A method for inspecting a member for a battery includes: a conveyance and measurement step of, with a member for a battery having at least resin collectors and having an exposure surface on which the resin collectors are exposed as an object of inspection, conveying the member for a battery with a conveying mechanism having a conveyance surface parallel to the exposure surface of the member for a battery and bringing a conductor probe into contact with a position on the surface of the member for a battery in conduction with the exposure surface, thereby measuring the electrical characteristics at a plurality of places on the surface of the member for a battery; and a determination step of determining whether a place with the electrical characteristics being outside an allowable range is present in the member for a battery.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to a method for inspecting a battery member, a method for manufacturing a battery member, and a method for manufacturing an assembled battery.

As the demand for large-capacity batteries increases and many assembled batteries in which a plurality of single cells are stacked are manufactured, there is an increasing need to efficiently remove defective products in the manufacturing process.

Patent Document 1 discloses a battery short-circuit inspection method in which an electrode plate group formed by laminating a positive electrode plate and a negative electrode plate with a separator interposed therebetween is inserted into a battery case. A battery short-circuit inspection method is disclosed in which short-circuit defects are inspected while applying pressure to the electrode plate group before the assembly.

Patent Document 2 discloses a method for inspecting a unit cell that constitutes an assembled battery, wherein a plurality of unit cells are arranged in a stack, and each unit cell is inspected in a state in which the arrayed unit cell group is pressed in the stacking direction. A method for inspecting a unit cell is disclosed.

JP-A-2001-236985 JP 2005-339925 A

However, in the inspection method described in Patent Literature 1, short circuit defects are inspected in a state in which pressure is applied to the electrode plate group in which the unit cells are assembled. It is not easy to identify what is happening.

On the other hand, in the inspection method described in Patent Document 2, each unit cell is inspected while the unit cell group arranged in a stack is pressed in the stacking direction, so if a defect is found in the unit cell group, a defect occurs. It is necessary to replace the battery that is in the battery pack.

As described above, the conventional inspection method detects defects in unit cells, more specifically, in units of battery members such as resin current collectors, electrode sheets, electrode sheets with separators, and battery sheets used in unit cells. It wasn't an efficient way to find out. Furthermore, the conventional inspection method is not a method for efficiently discovering defects, which causes a decrease in manufacturing efficiency.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for inspecting battery members that can easily detect defects such as short circuits and contribute to improving manufacturing efficiency. It is. Another object of the present invention is to provide a method for manufacturing a battery member using the method for inspecting a battery member. A further object of the present invention is to provide a method for manufacturing an assembled battery using the method for inspecting battery members.

In the present invention, a battery member having at least a resin current collector and an exposed surface where the resin current collector is exposed is used as an inspection object, and a conveying surface parallel to the exposed surface of the battery member is measured. The battery member is transported by the transport mechanism having the electric characteristic at a plurality of locations on the surface of the battery member by bringing the conductor probe into contact with the exposed surface of the surface of the battery member at a position where it conducts. and a determination step of determining whether or not the battery member has a portion where the electrical characteristics are out of the allowable range. A method for inspecting a battery member characterized by comprising a sorting step of sorting a battery member determined by the inspection method of the battery member that there is no location where the electrical characteristics are out of the allowable range. Manufacturing method; comprising a stacking step of stacking a plurality of battery sheets using the battery member determined by the inspection method for the battery member that there is no portion where the electrical characteristics are out of the allowable range. It is a manufacturing method of the assembled battery characterized by this.

ADVANTAGE OF THE INVENTION According to this invention, malfunctions, such as a short circuit, can be easily discovered by a battery member unit. Furthermore, according to the present invention, the number of processes can be reduced by simultaneously performing the transport process, which is part of the manufacturing process, and the measuring process, which is part of the inspection process. can be reduced, the manufacturing efficiency of battery members can be improved. As a result, it is possible to manufacture the assembled battery using the single cells that do not have any problems, so that the manufacturing yield of the assembled battery can be improved.

FIG. 1 is a schematic perspective view showing an example of the method for inspecting a battery member according to the present invention. FIG. 2 is a schematic perspective view showing an example of the method for inspecting a battery member according to the present invention, showing the latter stage of FIG. FIG. 3 is a schematic perspective view showing an example of the method for inspecting a battery member according to the present invention, showing the latter stage of FIG. FIG. 4 is a schematic perspective view showing another example of the method for inspecting a battery member according to the present invention. FIG. 5 is a schematic perspective view showing another example of the method for inspecting a battery member according to the present invention, showing the latter stage of FIG. FIG. 6 is a schematic perspective view showing another example of the method for inspecting a battery member according to the present invention, showing the latter stage of FIG. FIG. 7 is a partially cutaway schematic perspective view showing an example of a battery sheet used as a battery member in the battery member inspection method of the present invention. FIG. 8 is a partially cutaway schematic perspective view showing an example of an assembled battery.

[Method for inspecting battery member]
In the method for inspecting a battery member of the present invention, a battery member having at least a resin current collector and an exposed surface where the resin current collector is exposed is used as an inspection object. The battery member is transported by a transport mechanism having a smooth transport surface, and the conductor probe is brought into contact with the exposed surface of the surface of the battery member at a position where it conducts. and a determination step of determining whether or not the battery member has a portion where the electrical characteristics are out of the allowable range.

In the method for inspecting a battery member of the present invention, electrical resistance is measured as a first aspect of electrical characteristics. More specifically, in the method for inspecting a battery member of the present invention, electrical resistance is measured as an electrical characteristic in the transportation and measurement steps, and in the determination step, a portion where the electrical resistance is outside the allowable range is detected in the battery member. Determine if it exists.

The battery member, which is the inspection object, is desired to have a uniform resistance distribution in the plane. Therefore, in the method for inspecting a battery member according to the present invention, if the battery member has a portion where the measured electrical resistance is out of the allowable range, it is determined that the battery member is defective. The increase in electrical resistance is caused by poor dispersion of the conductive material, leading to deterioration in battery resistance. On the other hand, the decrease in electrical resistance is caused by a micro short circuit in which a portion that should be insulated becomes conductive and the electrical resistance decreases, leading to deterioration of battery quality and reliability in the event of an abnormality.

In the battery member inspection method of the present invention, the allowable range of electrical resistance is preferably ±30% of a predetermined value that depends on electrode specifications. The predetermined value can also be obtained from the average value of electrical resistances measured at a plurality of locations on the surface of the battery member, which is the inspection object.

In the battery member inspection method of the present invention, the voltage is measured as the second aspect of the electrical characteristics. More specifically, in the method for inspecting a battery member of the present invention, the voltage is measured as an electrical property in the transportation and measurement steps, and in the determination step, the battery member has a portion where the voltage is out of the allowable range. Determine whether or not

When the battery member to be inspected has a short-circuited portion, the voltage of the short-circuited portion is 0V. Therefore, when the conductor probe is brought into contact with the short-circuited portion at a pinpoint, the voltage at that portion becomes 0 V, for example, although the voltage at the other portion is approximately 100 mV. On the other hand, depending on the size of the conductor probe, the voltage at the short-circuited portion and the surrounding non-shorted portion may be measured together. In this case, the voltage to be measured is not 0V because the value includes not only the short-circuited portion but also the non-short-circuited portion, and is, for example, about 50 mV. In view of such behavior, in the battery member inspection method of the present invention, when the battery member has a portion where the measured voltage is out of the allowable range, it is determined that the battery member has a short-circuited portion.

In the battery member inspection method of the present invention, the allowable voltage range is preferably ±30% of a predetermined value that depends on electrode specifications. The predetermined value can also be obtained from the average value of the voltages measured at a plurality of points on the surface of the battery member, which is the object to be inspected.

As described above, in the battery member inspection method of the present invention, defects such as a short circuit can be easily found for each battery member.

In the method for inspecting a battery member according to the present invention, a battery member having at least a resin collector is used as an inspection object. On the other hand, in a battery member having a conventional metal current collector, the electrical resistance in the lateral direction (plane direction) is low, and the current is uniform within the plane. Therefore, when a battery member having a metal current collector is to be inspected, defects such as a short circuit cannot be found even by the method for inspecting a battery member according to the present invention. Thus, it can be said that the method for inspecting a battery member of the present invention is effective only for a battery member having a resin current collector.

In the method for inspecting a battery member according to the present invention, the following aspects are used as the battery member to be inspected.

In the method for inspecting a battery member of the present invention, a battery sheet is used as the first aspect of the battery member. More specifically, in the battery member inspection method of the present invention, the resin current collector includes a positive electrode resin current collector and a negative electrode resin current collector, and the battery members are stacked in order in the stacking direction. A battery sheet having a positive electrode resin current collector, a positive electrode active material layer, a separator, a negative electrode active material layer, and a negative electrode resin current collector, wherein the exposed surface of the battery member is the positive electrode exposed surface where the positive electrode resin current collector is exposed. and a negative electrode exposed surface where the negative electrode resin current collector is exposed, and in the transporting and measuring step, the conductor probe is brought into contact with one of the positive electrode exposed surface and the negative electrode exposed surface.

In the method for inspecting a battery member of the present invention, the battery sheet used as the first aspect of the battery member is synonymous with a cell. Battery sheets, that is, cells, include, for example, lithium ion batteries. In this specification, the concept of lithium ion battery includes lithium ion secondary battery.

In the method for inspecting a battery member of the present invention, a resin current collector is used as the second aspect of the battery member. More specifically, in the battery member inspection method of the present invention, the battery member is a resin current collector.

In the battery member inspection method of the present invention, an electrode sheet is used as the third aspect of the battery member. More specifically, in the battery member inspection method of the present invention, the battery member is an electrode sheet formed by laminating a resin current collector and an active material layer in the lamination direction.

In the battery member inspection method of the present invention, the electrode sheet used as the third aspect of the battery member is, for example, a positive electrode in which a positive electrode resin current collector and a positive electrode active material layer constituting the battery sheet are laminated. A sheet, a negative electrode sheet in which a negative electrode resin current collector and a negative electrode active material layer are laminated, and the like.

In the method for inspecting a battery member of the present invention, an electrode sheet with a separator is used as the fourth aspect of the battery member. More specifically, in the battery member inspection method of the present invention, the battery member is a separator-attached electrode sheet in which a resin current collector, an active material layer, and a separator are laminated in order in the lamination direction.

In the method for inspecting a battery member of the present invention, the electrode sheet with a separator used as the fourth aspect of the battery member is, for example, a laminate of a positive electrode resin current collector, a positive electrode active material layer, and a separator, which constitute the battery sheet. and a negative electrode sheet with a separator formed by laminating a negative electrode resin current collector, a negative electrode active material layer, and a separator.

In this specification, the battery sheet, the resin current collector, the electrode sheet, and the separator-attached electrode sheet are referred to as battery members unless otherwise distinguished.

In the method for inspecting a battery member of the present invention, in the transporting and measuring step, the battery member is transported by a transport mechanism having a transport surface parallel to the exposed surface of the battery member, and the conductor probe is placed on the surface of the battery member. The electrical characteristics at a plurality of locations on the surface of the battery member are measured by contacting the exposed surface of the battery member at a location where electrical continuity is provided. As described above, in the method for inspecting a battery member of the present invention, a transportation step of transporting the battery member, which is a part of the manufacturing process, and a plurality of locations on the surface of the battery member, which is a part of the inspection process. The measuring step of measuring the electrical properties can be performed simultaneously. According to the method for inspecting a battery member of the present invention, the number of steps can be reduced by simultaneously performing the transportation step, which is a part of the manufacturing process, and the measuring step, which is a part of the inspection process. And, since the manufacturing space can be reduced, the manufacturing efficiency of the battery member can be improved.

In this specification, the surface of the battery member is a range that includes at least the exposed surface where the resin current collector is exposed and the position that conducts to the exposed surface.

In the method for inspecting a battery member of the present invention, the constituent material of the conductor probe is not particularly limited. is preferably made of a carbon material. More specifically, the constituent material of the tip portion of the conductor probe (the portion in contact with the surface of the battery member) is preferably a carbon material. The constituent material of the tip portion of the conductor probe may be a metallic material such as copper or aluminum.

In the battery member inspection method of the present invention, the form of the conductor probe is not particularly limited. It is preferred to have

In the battery member inspection method of the present invention, when the conductor probe has a plurality of measurement terminals, the plurality of measurement terminals are arranged along the direction in which the battery member is conveyed and in a direction perpendicular to the direction of conveyance. is preferred.

In the battery member inspection method of the present invention, when the conductor probe has a plurality of measurement terminals, the plurality of measurement terminals preferably protrude in the same direction. More specifically, it is preferable that the plurality of measurement terminals protrude in the direction toward the battery member when they are brought into contact with the surface of the battery member.

In the battery member inspection method of the present invention, when the conductor probe has a plurality of measuring terminals, the interval between adjacent measuring terminals is not particularly limited, but is preferably equal.

In the battery member inspection method of the present invention, the shape of the tip portion of the conductor probe, for example, the shape of the tip portion of the measuring terminal is not particularly limited, and examples thereof include a rectangle and a square.

In the battery member inspection method of the present invention, the area of the tip portion of the conductor probe, for example, the area of the tip portion of the measurement terminal is not particularly limited. Increased measurement sensitivity. From this point of view, the area of the tip portion of the conductor probe, for example, the area of the tip portion of the measuring terminal, is preferably 12 cm ² or less.

In the battery member inspection method of the present invention, the pressure when the conductive probe, for example, the measuring terminal is brought into contact with the surface of the battery member is not particularly limited, but is preferably 5 kPa or more.

In the method for inspecting a battery member of the present invention, the transport mechanism for transporting the battery member is not particularly limited. is preferred.

In the battery member inspection method of the present invention, the transport mechanism is preferably a belt conveyor. By using a belt conveyor as the transport mechanism, the conductor probe can be easily brought into contact with the surface of the battery member.

In the battery member inspection method of the present invention, when the transport mechanism is a belt conveyor, the belt conveyor preferably has a conductive belt. In this case, the electrical characteristics at a plurality of locations on the surface of the battery member are measured by bringing the surface of the battery member into contact with the conductive belt and conductor probes of the belt conveyor. In other words, the conductive belt of the belt conveyor can perform not only the function of conveyance but also the same function as the conductive probe.

In the method for inspecting a battery member of the present invention, a belt conveyor having a conductive belt is used as a transport mechanism at least during the measurement of the electrical characteristics by contacting the conductive probe to the surface of the battery member. Just do it. Before and after measuring the electrical properties of the battery member, a belt conveyor having a conductive belt or a belt conveyor having a non-conductive belt may be used as the transport mechanism.

In the method for inspecting a battery member of the present invention, from the viewpoint of easily measuring the electrical characteristics at multiple locations on the surface of the battery member, the following aspects are adopted in addition to the above-described preferable transfer mechanism. It is also preferable to

In the method for inspecting a battery member of the present invention, it is preferable that the battery member is conveyed in a state of being stacked on a conductive conveying tray in the conveying and measuring step. In this case, the electrical characteristics at a plurality of locations on the surface of the battery member are measured by contacting the surface of the battery member with a conductive carrier tray and a conductor probe. That is, the conductive carrier tray can perform the same function as the conductive probe.

In the battery member inspection method of the present invention, when a conductive transport tray is used, the transport tray is provided with a conductive probe, and in the transport and measurement process, the probe provided on the transport tray is It is preferable to contact the surface of the member. In this case, the probe and the conductor probe provided on the carrier tray can be brought into contact with the surface of the battery member while facing each other with the battery member interposed therebetween. It is possible to more reliably detect defective parts.

In the battery member inspection method of the present invention, when a conductive carrier tray provided with conductive probes is used, the probes provided on the carrier tray are preferably integrated with the same material as the carrier tray. . In this case, since the conductivity between the carrier tray and the probes provided thereon is enhanced, the electrical characteristics at a plurality of locations on the surface of the battery member can be measured more accurately.

In the battery member inspection method of the present invention, when a conductive carrier tray provided with conductive probes is used, the material of the probes provided on the carrier tray is not particularly limited, but metal contamination is prevented. It is preferable that the probes provided on the carrier tray are made of a carbon material, from the viewpoint of performing measurement and improving the measurement sensitivity. More specifically, the constituent material of the tip portion of the probe provided on the carrier tray (the portion that comes into contact with the surface of the battery member) is preferably a carbon material. The constituent material of the tip portion of the probe provided on the carrier tray may be a metallic material such as copper or aluminum.

In the method for inspecting a battery member of the present invention, when a conductive transport tray provided with a conductive probe is used, the shape of the tip portion of the probe provided on the transport tray is not particularly limited. A rectangle, a square, etc. are mentioned.

In the method for inspecting a battery member of the present invention, when a conductive transfer tray provided with conductive probes is used, the area of the tip portion of the probe provided on the transfer tray is not particularly limited, but the area is small. Indeed, since local information can be obtained, the measurement sensitivity increases. From this point of view, the area of the tip portion of the probe provided on the carrier tray is preferably 12 cm ² or less.

In the battery member inspection method of the present invention, when a conductive transfer tray provided with conductive probes is used, the pressure when the probes provided on the transfer tray are brought into contact with the surface of the battery member is particularly Although not limited, it is preferably 5 kPa or more.

In the battery member inspection method of the present invention, when a conductive transport tray is used, a belt conveyor having a conductive belt may be used as the transport mechanism, or a belt conveyor having a non-conductive belt may be used. may be used.

In the method for inspecting a battery member of the present invention, when the battery member is the electrode sheet with a separator described above, at least one of a belt conveyor having a conductive belt and a conductive transport tray is used. However, the exposed surface of the electrode sheet with the separator where the resin current collector is exposed is turned to the side opposite to the conveying surface, and then the conductor probe is brought into contact with the exposed surface.

In the battery member inspection method of the present invention, when the battery member is transported by the transport mechanism and the conductor probe is brought into contact with the surface of the battery member, the conductor probe is moved to the battery member according to the transport speed. It is preferable to follow. In other words, it is preferable to move the conductor probe at the same transport speed as the battery member while keeping contact with the surface of the battery member. As a result, the transportation of the battery member and the measurement of the electrical properties at a plurality of locations on the surface of the battery member can be performed simultaneously and efficiently.

FIG. 1 is a schematic perspective view showing an example of the method for inspecting a battery member according to the present invention.

In FIG. 1, the battery member 1 is conveyed in the conveying direction L1 using the belt conveyor (conveying mechanism) 2 .

The battery member 1 has an exposed surface (at least one of the upper surface and the lower surface in FIG. 1) where the resin current collector is exposed.

The belt conveyor 2 has a conveying surface parallel to the exposed surface of the battery member 1 .

The belt conveyor 2 has a conductive belt as a component of the conveying surface.

A conductor probe 3 is arranged above the conveying surface of the belt conveyor 2, that is, on the opposite side of the battery member 1 from the belt conveyor 2 in FIG. The conductor probe 3 is configured to be able to follow the battery member 1 according to the transport speed.

The conductor probe 3 has a plurality of measuring terminals 3a.

The plurality of measurement terminals 3a are arranged along the conveying direction L1 of the battery member 1 and the direction L2 orthogonal to the conveying direction L1. Thereby, the conductor probe 3 can be brought into contact with a wide range of the surface of the battery member 1 at the time of measuring the electrical properties of the battery member 1 to be described later.

The plurality of measurement terminals 3a protrude in the same direction (downward in FIG. 1) toward the battery member 1. As shown in FIG.

The interval between adjacent measurement terminals 3a is not particularly limited, but is preferably equal.

Note that the plurality of measurement terminals 3a may be arranged in a so-called zigzag shape along the transport direction L1. Also, the plurality of measurement terminals 3a may be arranged in a so-called zigzag shape along the direction L2 perpendicular to the transport direction L1.

Procedures of the inspection method for the battery member 1 will be described below with reference to FIGS. 2 and 3 in addition to FIG. FIG. 2 is a schematic perspective view showing an example of the method for inspecting a battery member according to the present invention, showing the latter stage of FIG. FIG. 3 is a schematic perspective view showing an example of the method for inspecting a battery member according to the present invention, showing the latter stage of FIG.

First, as shown in FIG. 1, the belt conveyor 2 is used to transport the battery member 1 in the transport direction L1.

Next, as shown in FIG. 2, the conductor probe 3 is brought into contact with the surface (upper surface in FIG. 2) of the battery member 1 being conveyed by the belt conveyor 2 . At this time, the conductor probe 3 is brought into contact with the surface of the battery member 1 while following the battery member 1 according to the transport speed. The conductive probe 3 may be brought into contact with the surface of the battery member 1 by lowering it at the timing when the battery member 1 is conveyed downward.

Then, the conductor probe 3 is moved at the same transport speed as the battery member 1 while being kept in contact with the surface of the battery member 1 . At this time, electrical characteristics are measured (monitored) at a plurality of locations on the surface of the battery member 1 using a measuring device 4 for measuring electrical characteristics, which is connected to the belt of the belt conveyor 2 and the conductor probe 3 .

After that, as shown in FIG. 3 , the conductor probe 3 is separated from the surface of the battery member 1 .

By repeating the procedure shown in FIGS. 1, 2, and 3, the electrical properties of a plurality of battery members 1 can be continuously measured.

FIG. 4 is a schematic perspective view showing another example of the method for inspecting a battery member according to the present invention.

In FIG. 4, the battery member 1 is conveyed in the conveying direction L1 using the belt conveyor 2 while being stacked on the conductive conveying tray 5 .

The transport tray 5 may be entirely made of a conductive material on its surface and inside, or may be made of a conductive material only on its surface.

The transport tray 5 is provided with a plurality of conductive probes 5a. More specifically, the plurality of probes 5 a provided on the carrier tray 5 are integrated with the same material as the carrier tray 5 .

A plurality of probes 5 a provided on the carrier tray 5 protrude in the same direction (upward in FIG. 4 ) toward the battery member 1 .

A plurality of probes 5a provided on the carrier tray 5 are in contact with the surface of the battery member 1 (lower surface in FIG. 4).

The interval between adjacent probes 5a is not particularly limited, but is preferably equal.

In addition, the plurality of probes 5a may be arranged in a so-called zigzag shape along the transport direction L1. Also, the plurality of probes 5a may be arranged in a so-called zigzag shape along the direction L2 orthogonal to the transport direction L1.

The belt of the belt conveyor 2 and the transport tray 5 are electrically connected by contact.

Note that, unlike the state shown in FIG. 4, a belt conveyor having a non-conductive belt may be used instead of the belt conveyor 2. FIG.

Procedures of an inspection method for the battery member 1 stacked on the carrier tray 5 will be described below with reference to FIGS. 5 and 6 in addition to FIG. FIG. 5 is a schematic perspective view showing another example of the method for inspecting a battery member according to the present invention, showing the latter stage of FIG. FIG. 6 is a schematic perspective view showing another example of the method for inspecting a battery member according to the present invention, showing the latter stage of FIG.

First, as shown in FIG. 4, the belt conveyor 2 is used to transport the battery member 1 stacked on the transport tray 5 in the transport direction L1.

Next, as shown in FIG. 5, the conductor probe 3 is brought into contact with the surface (upper surface in FIG. 5) of the battery member 1 being conveyed by the belt conveyor 2 . At this time, the conductor probe 3 is brought into contact with the surface of the battery member 1 while following the battery member 1 according to the transport speed. The conductive probe 3 may be brought into contact with the surface of the battery member 1 by lowering it at the timing when the battery member 1 is conveyed downward.

Then, the conductor probe 3 is moved at the same transport speed as the battery member 1 while being kept in contact with the surface of the battery member 1 . At this time, electrical characteristics are measured at a plurality of locations on the surface of the battery member 1 using a measuring device 4 connected to the belt of the belt conveyor 2 and the conductor probe 3 .

Incidentally, instead of the belt of the belt conveyor 2, the transport tray 5 may be connected to the measuring device 4. FIG. That is, the carrier tray 5 and the conductor probes 3 may be connected to the measuring device 4 . Also in this case, the electrical properties at multiple points on the surface of the battery member 1 can be measured using the measuring device 4 .

After that, as shown in FIG. 6 , the conductor probe 3 is separated from the surface of the battery member 1 .

By repeating the procedures shown in FIGS. 4, 5, and 6, the electrical characteristics of a plurality of battery members 1 individually stacked on the carrier tray 5 can be continuously measured.

Examples of the method for inspecting battery members according to the present invention will be described below. The method for inspecting a battery member according to the present invention is not limited to the following examples.

[Example 1]
In Example 1, first, as shown in FIG. 4, the belt conveyor 2 was used to transport the battery member 1 stacked on the transport tray 5 in the transport direction L1 at a transport speed of 20 m/min.

A battery sheet was used as the battery member 1 .

The belt conveyor 2 had a conductive belt as a component of the conveying surface.

The transport tray 5 had a size of 8 cm long×6 cm wide, and its surface was made of a conductive material. Note that the transport tray 5 used in this example was not provided with the conductive probes 5a, unlike FIG.

Next, as shown in FIG. 5, the surface of the battery member 1 conveyed by the belt conveyor 2 was brought into contact with the conductor probe 3 having a plurality of measuring terminals 3a each having a tip area of 12 cm ² . At this time, the conductor probe 3 was brought into contact with the surface of the battery member 1 while being pressed so that a pressure of 5 kPa was applied to the measuring terminal 3a.

Then, the conductor probe 3 was moved at the same transport speed as the battery member 1 while being kept in contact with the surface of the battery member 1 . At this time, the electrical resistance of the battery member 1 was monitored using a measuring device 4 connected to the belt of the belt conveyor 2 and the conductor probe 3 . As the measuring device 4, a chemical impedance analyzer "IM3590" manufactured by Hioki Electric Co., Ltd. was used.

One second after bringing the conductor probe 3 into contact with the surface of the battery member 1, the conductor probe 3 was separated from the surface of the battery member 1 as shown in FIG.

[Example 2]
The electrical resistance of the battery member 1 was monitored in the same manner as in Example 1, except that the area of the tip portion of the measuring terminal 3a was changed to 24 cm ² .

[Example 3]
The electrical resistance of the battery member 1 was monitored in the same manner as in Example 1, except that the area of the tip portion of the measuring terminal 3a was changed to 48 cm ² .

In Example 1, Example 2, and Example 3, the electrical resistance of the battery member 1 was monitored. Table 1 shows the difference between the two (“electrical resistance at abnormal location”−“average electrical resistance in normal region”).

As shown in Table 1, in Example 1, Example 2, and Example 3, it was confirmed that the electrical resistance was lower than that in the normal region at the abnormal location where the short circuit was intentionally made.

[Example 4]
The battery member 1 was inspected in the same manner as in Example 1, except that the voltage of the battery member 1 was monitored by using a memory high logger “LR8401” manufactured by Hioki Electric Co., Ltd. as the measuring device 4 .

[Example 5]
The voltage of the battery member 1 was monitored in the same manner as in Example 4, except that the area of the tip portion of the measuring terminal 3a was changed to 24 cm ² .

[Example 6]
The voltage of the battery member 1 was monitored in the same manner as in Example 4, except that the area of the tip portion of the measuring terminal 3a was changed to 48 cm ² .

In Examples 4, 5, and 6, as a result of monitoring the voltage of the battery member 1, the average voltage in the normal region, the voltage at the abnormal location where the short circuit was intentionally made, and the difference between the two (“Voltage at abnormal point”−“Average voltage in normal region”) is as shown in Table 2.

As shown in Table 2, in Example 4, Example 5, and Example 6, an event was confirmed in which the voltage dropped below the normal region at the abnormal location where the short circuit was intentionally made.

FIG. 7 is a partially cutaway schematic perspective view showing an example of a battery sheet used as a battery member in the battery member inspection method of the present invention.

A battery sheet (single cell) 10 shown in FIG. A negative electrode 13 having a negative electrode active material layer 16 provided on the surface of the negative electrode 19 is laminated with a substantially flat plate-shaped separator 14 interposed therebetween to form a substantially rectangular plate shape as a whole. Positive electrode 12 and negative electrode 13 function, for example, as a positive electrode and a negative electrode of a lithium ion battery, respectively.

The battery sheet 10 is arranged between the positive electrode resin current collector 17 and the negative electrode resin current collector 19 to fix the periphery of the separator 14 , and also includes the positive electrode active material layer 15 , the separator 14 and the negative electrode active material layer 16 . It is preferable to have an annular frame member 18 that seals the .

The positive electrode resin current collector 17 and the negative electrode resin current collector 19 are positioned by the frame member 18 so as to face each other with a predetermined gap, and the separator 14 and the positive electrode active material layer 15, and the separator 14 and the negative electrode active material layer. 16 are also positioned by a frame member 18 so as to face each other with a predetermined spacing.

The distance between the positive electrode resin current collector 17 and the separator 14 and the distance between the negative electrode resin current collector 19 and the separator 14 are adjusted according to the capacity of the battery sheet 10, for example, the lithium ion battery. In this manner, the positional relationship among the positive electrode resin current collector 17, the negative electrode resin current collector 19, and the separator 14 is determined so as to obtain the required spacing.

Preferred aspects of each component of the battery sheet are described below. The same applies to preferred aspects of each constituent element of the resin current collector, the electrode sheet, and each constituent element of the separator-attached electrode sheet.

The positive electrode active material layer contains a positive electrode active material.

Examples of positive electrode active materials include composite oxides of lithium and transition metal {composite oxides containing one type of transition metal element (eg, LiCoO ₂ , LiNiO ₂ , LiAlMnO ₄ , LiMnO ₂ , LiMn ₂ O ₄ , etc.) , composite oxides containing two types of transition metal elements (for example, LiFeMnO ₄ , LiNi _1-x Co _x O ₂ , LiMn _1-y Co _y O ₂ , LiNi _1/3 Co _1/3 Al _1/3 O ₂ , LiNi _0.8 Co _0.15 Al _0.05 O _2, etc.), composite oxides containing three or more transition metal elements [for example, LiM _a M′ _b M″ _c O ₂ (M, M′, _and M'' are _respectively different transition metal elements and satisfy a+b _{+ c} =1. salts (e.g. _LiFePO4 , _LiCoPO4 , _LiMnPO4 , _LiNiPO4 etc.), transition metal oxides (e.g. _MnO2 , _{V2O5 etc.} ), transition metal sulfides (e.g. _MoS2 , _TiS2 etc.), conductive polymers (eg, polyaniline, polypyrrole, polythiophene, polyacetylene, poly-p-phenylene, polyvinylcarbazole, etc.); The lithium-containing transition metal phosphate may have a transition metal site partially substituted with another transition metal.

One of the positive electrode active materials described above may be used alone, or two or more of them may be used in combination.

The positive electrode active material is preferably a coated positive electrode active material coated with a conductive aid and a coating resin. When the positive electrode active material is coated with the coating resin, the volume change of the electrode is moderated, so expansion of the electrode can be suppressed.

Examples of conductive aids include metallic conductive aids [e.g., aluminum, stainless steel (SUS), silver, gold, copper, titanium, etc.], carbon-based conductive aids [e.g., graphite, carbon black (acetylene black, chain black, furnace black, channel black, thermal lamp black, etc.], mixtures thereof, alloys thereof, metal oxides thereof, and the like. Among them, from the viewpoint of electrical stability, aluminum, stainless steel, silver, gold, copper, titanium, carbon-based conductive additives, and mixtures thereof are preferable, and silver, gold, aluminum, stainless steel, and carbon-based conductive additives are preferable. agent is more preferable, and a carbon-based conductive aid is particularly preferable.

The conductive aid may be a particulate ceramic material or a resin material coated with a conductive material (preferably a metallic one among the conductive aids described above) by plating or the like.

One type of the conductive aids described above may be used alone, or two or more types may be used in combination.

The form (shape) of the conductive aid is not particularly limited, and may be in the form of particles, or may be in a form other than the form of particles. Regarding the conductive aid, the form other than the particle form may be a form that has been put into practical use as a so-called filler-based conductive aid, such as carbon nanofibers and carbon nanotubes.

The ratio of the coating resin and the conductive aid is not particularly limited, but from the viewpoint of the internal resistance of the battery, etc., the weight ratio of the coating resin (resin solid content weight): conductive aid is from 1:0.01. It is preferably 1:50, more preferably 1:0.2 to 1:3.0.

As the coating resin, those described as non-aqueous secondary battery active material coating resins in JP-A-2017-054703 are preferably used.

The positive electrode active material layer may further contain another conductive support agent in addition to the conductive support agent contained in the coated positive electrode active material.

As another conductive aid, the same one as the conductive aid contained in the above-described coated positive electrode active material is preferably used.

The positive electrode active material layer is preferably a non-binding material that contains a positive electrode active material and does not contain a binder (also referred to as a binder) that binds the positive electrode active materials together.

The non-bound body means that the position of the positive electrode active material is not fixed by a binder, and the positive electrode active material and the current collector are not fixed irreversibly. .

The positive electrode active material layer may further contain an adhesive resin.

As the adhesive resin, for example, a non-aqueous secondary battery active material coating resin described in JP-A-2017-054703 is mixed with a small amount of an organic solvent to adjust its glass transition temperature to room temperature or lower. Those described as adhesives in JP-A-10-255805 are preferably used.

Adhesive resin means a resin that does not solidify even when the solvent component is volatilized and dried, and has adhesiveness (the property of adhering by applying a slight pressure without using water, solvent, heat, etc.) do. On the other hand, a solution-drying type electrode binder used as a binding material is one that evaporates a solvent component to dry and solidify, thereby firmly adhering and fixing active materials to each other. Thus, the solution-drying type electrode binder (binder) and the adhesive resin are different materials.

Although the thickness of the positive electrode active material layer is not particularly limited, it is preferably 150 to 600 μm, more preferably 200 to 450 μm from the viewpoint of battery performance.

The negative electrode active material layer contains a negative electrode active material.

As the negative electrode active material, known negative electrode active materials for lithium ion batteries can be used. carbonized resin etc.), cokes (e.g., pitch coke, needle coke, petroleum coke, etc.), carbon fiber, etc.], silicon-based materials [e.g., silicon, silicon oxide (SiOx), silicon-carbon Composites (e.g., carbon particles coated with silicon and/or silicon carbide, silicon particles or silicon oxide particles coated with carbon and/or silicon carbide, silicon carbide, etc.), silicon alloys (e.g. , silicon-aluminum alloy, silicon-lithium alloy, silicon-nickel alloy, silicon-iron alloy, silicon-titanium alloy, silicon-manganese alloy, silicon-copper alloy, silicon-tin alloy, etc.)], conductive polymer ( polyacetylene, polypyrrole, etc.), metals (e.g., tin, aluminum, zirconium, titanium, etc.), metal oxides (e.g., titanium oxides, lithium-titanium oxides, etc.), metal alloys (e.g., lithium-tin alloys, lithium-aluminum alloys, lithium-aluminum-manganese alloys, etc.), mixtures of these with carbonaceous materials, and the like.

One type of the negative electrode active material described above may be used alone, or two or more types may be used in combination.

The negative electrode active material may be a coated negative electrode active material coated with a conductive aid and a coating resin. When the negative electrode active material is coated with the coating resin, the volume change of the electrode is moderated, so expansion of the electrode can be suppressed.

As the conductive aid and coating resin contained in the coated negative electrode active material, the same conductive aid and coating resin as those contained in the coated positive electrode active material described above are preferably used.

The negative electrode active material layer may further contain another conductive support agent in addition to the conductive support agent contained in the coated negative electrode active material.

As another conductive aid, the same one as the conductive aid contained in the above-described coated positive electrode active material is preferably used.

Like the positive electrode active material layer, the negative electrode active material layer is preferably a non-binding material that does not contain a binder that binds the negative electrode active materials together.

Like the positive electrode active material layer, the negative electrode active material layer may further contain an adhesive resin.

Although the thickness of the negative electrode active material layer is not particularly limited, it is preferably 150 to 600 μm, more preferably 200 to 450 μm from the viewpoint of battery performance.

Each of the positive electrode resin current collector and the negative electrode resin current collector is a resin current collector made of a conductive polymer material.

The form (shape) of the positive electrode resin current collector and the negative electrode resin current collector is not particularly limited, and may be a sheet-like current collector made of a conductive polymer material, or a conductive polymer material. It may be a deposited layer composed of fine particles composed of

The thickness of each of the positive electrode resin current collector and the negative electrode resin current collector is not particularly limited, but is preferably 50 to 500 μm.

Examples of the conductive polymer material that constitutes the positive electrode resin current collector and the negative electrode resin current collector include conductive polymers and resins to which a conductive agent is added as necessary.

As the conductive agent that constitutes the conductive polymer material, the same conductive aid as that contained in the above-described coated positive electrode active material is preferably used.

Examples of resins constituting conductive polymer materials include polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), polycycloolefin (PCO), polyethylene terephthalate (PET), and polyethernitrile (PEN). , polytetrafluoroethylene (PTFE), styrene-butadiene rubber (SBR), polyacrylonitrile (PAN), polymethyl acrylate (PMA), polymethyl methacrylate (PMMA), polyvinylidene fluoride (PVdF), epoxy resin, silicone resin, these and the like. Among them, from the viewpoint of electrical stability, polyethylene, polypropylene, polymethylpentene, and polycycloolefin are preferred, and polyethylene, polypropylene, and polymethylpentene are more preferred.

The resins described above may be used singly or in combination of two or more.

As the separator, known lithium ion battery separators can be used. Aramid fiber, etc.) or nonwoven fabric made of glass fiber, etc., and those having ceramic fine particles such as silica, alumina, titania, etc. adhered to the surface thereof.

The battery sheet includes an electrolyte present in the positive electrode active material layer and the negative electrode active material layer.

As the electrolytic solution, a known electrolytic solution containing an electrolyte and a non-aqueous solvent, which is used in the production of known lithium ion batteries, can be used.

_{As the} electrolyte _, those used in _known electrolytic solutions _{can be} used _. Lithium salts of organic acids such as LiN(CF ₃ SO ₂ ) ₂ , LiN(C ₂ F ₅ SO ₂ ) ₂ and LiC(CF ₃ SO ₂ ) ₃ are included. Among them, imide-based electrolytes such as LiN(FSO ₂ ) ₂ , LiN(CF ₃ SO ₂ ) ₂ , LiN(C ₂ F ₅ SO ₂ ) ₂ and LiPF ₆ are preferred from the viewpoint of battery output and charge-discharge cycle characteristics. preferable.

As the non-aqueous solvent, those used in known electrolytic solutions can be used. compounds, amide compounds, sulfones, sulfolane, mixtures thereof, and the like.

The electrolyte concentration of the electrolytic solution is preferably 1 to 5 mol/L, more preferably 1.5 to 4 mol/L, still more preferably 2 to 3 mol/L.

If the electrolyte concentration of the electrolytic solution is lower than 1 mol/L, the battery may not have sufficient input/output characteristics. If the electrolyte concentration of the electrolytic solution is higher than 5 mol/L, the electrolyte may precipitate.

The electrolyte concentration of the electrolytic solution can be confirmed by extracting the electrolytic solution from a battery sheet, for example, a lithium ion battery without using a solvent or the like and measuring the concentration.

[Method for manufacturing battery member]
The method for manufacturing a battery member of the present invention comprises a sorting step of sorting out battery members determined by the method of inspecting a battery member of the present invention to have no portion where the electrical characteristics are out of the allowable range.

In the method for manufacturing a battery member of the present invention, the sorting step efficiently removes defective products that have locations where the electrical characteristics are out of the allowable range, and efficiently selects battery members that do not have locations where the electrical characteristics are out of the allowable range. can be obtained on a regular basis.

[Method for manufacturing assembled battery]
In the assembled battery manufacturing method of the present invention, a plurality of battery sheets using battery members determined by the method of inspecting battery members of the present invention to have electrical characteristics outside the allowable range are not present. , a lamination step.

FIG. 8 is a partially cutaway schematic perspective view showing an example of an assembled battery. FIG. 8 shows a state in which a portion of the exterior body is removed.

The assembled battery 100 shown in FIG. 8 is formed by stacking and connecting a plurality of battery sheets 10 . The example shown in FIG. 8 shows a state in which five battery sheets 10 shown in FIG. 7 are stacked. In the assembled battery 100, the battery sheets 10 are laminated such that the upper surface of the negative electrode resin current collector 19 and the lower surface of the positive electrode resin current collector 17 are adjacent to each other. In this case, a plurality of battery sheets 10 are connected in series.

The assembled battery 100 is housed in an exterior body 110 .

Examples of the exterior body 110 include a metal can case, a polymer-metal composite film, and the like.

A conductive sheet is provided on the surface of the positive electrode resin current collector that constitutes the bottom surface of the assembled battery 100 . A part of the conductive sheet is pulled out from the outer package 110 to serve as a positive electrode extraction terminal 120 .

Another conductive sheet is provided on the surface of the negative electrode resin current collector that constitutes the uppermost surface of the assembled battery 100 . A part of another conductive sheet is pulled out from the outer package 110 to serve as a negative electrode extraction terminal 130 .

The constituent material of the conductive sheet that serves as the positive electrode lead terminal 120 and the negative electrode lead terminal 130 is not particularly limited as long as it is a material having conductivity, and examples thereof include copper, aluminum, titanium, stainless steel, nickel, and alloys thereof. metal, calcined carbon, conductive polymer, conductive glass, and the like.

As described above, in the battery member inspection method of the present invention, defects such as a short circuit can be easily found for each battery member. As a result, in the assembled battery manufacturing method of the present invention, the assembled battery can be manufactured using the battery sheet without any defects, and thus the manufacturing yield of the assembled battery can be improved.

The battery member to be inspected by the battery member inspection method of the present invention is particularly useful for lithium ion batteries used in mobile phones, personal computers, hybrid vehicles, and electric vehicles.

1 battery member 2 belt conveyor (conveyance mechanism)
3 Conductor probe 3a Measuring terminal 4 Measuring device 5 Transport tray 5a Probe 10 Battery sheet (single cell)
12 Positive electrode 13 Negative electrode 14 Separator 15 Positive electrode active material layer 16 Negative electrode active material layer 17 Positive electrode resin current collector 18 Frame member 19 Negative electrode resin current collector 100 Battery assembly 110 Exterior body 120 Positive electrode extraction terminal 130 Negative extraction terminal L1 Conveyance direction L2 Conveyance direction orthogonal to direction

Claims (16)

A transport mechanism having a transport surface parallel to the exposed surface of the battery member having at least a resin current collector and having an exposed surface where the resin current collector is exposed as an inspection target. While conveying the battery member, a conductor probe is brought into contact with the exposed surface of the surface of the battery member, thereby measuring electrical characteristics at a plurality of locations on the surface of the battery member. a conveying and measuring process;
A method for inspecting a battery member, comprising: determining whether or not the battery member has a portion where the electrical characteristics are out of an allowable range. In the transporting and measuring step, electrical resistance is measured as the electrical property,
2. The method for inspecting a battery member according to claim 1, wherein, in said determining step, it is determined whether or not there is a portion in said battery member where said electrical resistance is out of an allowable range. In the conveying and measuring step, voltage is measured as the electrical characteristic,
2. The method for inspecting a battery member according to claim 1, wherein, in said determining step, it is determined whether or not there is a portion in said battery member where said voltage is out of an allowable range. The resin current collector includes a positive electrode resin current collector and a negative electrode resin current collector,
The battery member is a battery sheet having the positive electrode resin current collector, the positive electrode active material layer, the separator, the negative electrode active material layer, and the negative electrode resin current collector which are stacked in order in the stacking direction,
The exposed surface of the battery member includes a positive electrode exposed surface where the positive electrode resin current collector is exposed and a negative electrode exposed surface where the negative electrode resin current collector is exposed,
4. The method for inspecting a battery member according to claim 1, wherein in said transporting and measuring step, said conductor probe is brought into contact with one of said positive electrode exposed surface and said negative electrode exposed surface. 4. The method for inspecting a battery member according to claim 1, wherein said battery member is said resin current collector. 4. The method for inspecting a battery member according to claim 1, wherein said battery member is an electrode sheet in which said resin current collector and an active material layer are laminated in a lamination direction. Inspection of the battery member according to any one of claims 1 to 3, wherein the battery member is an electrode sheet with a separator in which the resin current collector, the active material layer and the separator are laminated in order in the lamination direction. Method. 8. The battery member inspection method according to claim 1, wherein said transport mechanism is a belt conveyor. 9. The battery member inspection method according to claim 8, wherein said belt conveyor has a conductive belt. 10. The method for inspecting a battery member according to claim 1, wherein, in said transporting and measuring step, said battery member is transported while being stacked on a conductive transport tray. The transport tray is provided with a conductive probe,
11. The method for inspecting a battery member according to claim 10, wherein in the transporting and measuring step, the probe provided on the transport tray is brought into contact with the surface of the battery member. 12. The battery member inspection method according to claim 11, wherein said probes provided on said carrier tray are integrated with the same material as said carrier tray. 13. The battery member inspection method according to claim 11, wherein said probes provided on said carrier tray are made of a carbon material. 14. The battery member inspection method according to claim 1, wherein said conductor probe is made of a carbon material. A screening step of selecting battery members determined by the battery member inspection method according to any one of claims 1 to 14 as not having a location where the electrical characteristics are out of the allowable range. A method for manufacturing a battery member. Laminating a plurality of battery sheets using battery members determined by the battery member inspection method according to any one of claims 1 to 14 that there is no location where the electrical characteristics are out of the allowable range, A method for manufacturing an assembled battery, comprising a stacking step.

Images