JP5090230B2 - Load-resistant insulation test apparatus for battery separator and test method thereof - Google Patents

Description

  The present invention relates to an insulation test apparatus for a film against a load and an insulation test method thereof.

  Conventionally, various standards for battery safety evaluation have been prepared in JIS, UL, and SBA standards. Patent Document 1 describes an example in which the measurement specified by the JIS standard is performed by a simpler method.

Japanese Patent Laid-Open No. 2003-14600

  An object of the present invention is to provide a test apparatus and a test method that can easily and safely evaluate the load-bearing insulation characteristics of a film.

The present invention for achieving the above object is an apparatus for performing an insulation test of a battery separator under a load,
A mounting table for mounting a battery separator ;
A contact terminal for applying a load by contacting the surface of the battery separator on the mounting table;
A moving mechanism capable of moving the contact terminal up and down to vary the load on the battery separator ;
And an electrical resistance measuring instrument for measuring electrical resistance of a battery separator between the mounting table and the contact terminal.
Here, the tip of the contact terminal has a spherical surface with a radius of curvature of 0.3 mm to 4.0 mm.
The tip of the contact terminal may be formed in a spherical shape.
The battery separator may have a thickness of 1 μm to 50 μm.
Further, the surface of the mounting table may be polished with an abrasive of # 100 to # 10000.

On the other hand, the test method of the present invention is a method for performing an insulation test of a battery separator under a load, and the curvature radius is 0.3 mm to the surface of the battery separator placed on the mounting table. A contact terminal having a 4.0 mm spherical surface is contacted to apply a load to the battery separator , and while the load is gradually increased, the electric resistance of the battery separator between the mounting table and the contact terminal is increased by an electric resistance measuring instrument. A resistance is measured, and a load when the battery separator is short-circuited is detected.
Here, the lowering speed of the contact terminal when a load is applied to the contact terminals into contact with the cell separator surface battery separator may be a 5μm / min~100μm / min.
In addition, the battery separator and the positive electrode member or negative electrode member of the battery are stacked and sandwiched between the contact terminal and the mounting table, and the electric resistance of the battery separator can be measured.
Furthermore, the thickness of the battery separator can be 1 μm to 100 μm.

  ADVANTAGE OF THE INVENTION According to this invention, the test apparatus and test method which can evaluate the load bearing insulation characteristic of a film simply and safely are provided.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing an outline of the configuration of a load-bearing insulation test apparatus 1 according to the present embodiment.

  The load-bearing insulation test apparatus 1 includes, for example, a mounting table 10 on which a battery separator A as a film to be tested is mounted, a contact terminal 11 that contacts the surface of the separator A on the mounting table 10 and applies a load, The electric resistance of the separator A sandwiched between the mounting table 10 and the contact terminal 11 by applying a voltage between the mounting table 10 and the contact terminal 11 by moving the contact terminal 11 up and down to change the load. And an electric resistance measuring device 13 for measuring.

The mounting table 10 is made of, for example, a good conductor such as aluminum or stainless steel. As a material for the mounting table 10, a material having high conductivity and being difficult to be deformed or worn is preferable.
Further, the mounting table 10 is formed in a thick disk shape as shown in FIG. 2, for example, but may be a square disk shape.

The surface roughness of the mounting surface of the mounting table 10 is preferably, for example, a surface roughness that does not have irregularities such that the surface shape is transferred to the separator A, and has a surface roughness that is smaller than the surface roughness of the separator A. Is preferred. Such surface roughness reduces the influence of the contact resistance between the separator A and the mounting table 10 and can more accurately measure the electrical resistance of the separator A itself. As a result, the electrical resistance of the separator A can be measured. It is preferable that the short-circuit load based on can be detected more accurately.
Specifically, it is preferable to have a smoothness of a mirror surface level polished with an abrasive of # 100 to # 10000, preferably # 500 to # 4000.
Further, the arithmetic average roughness (Ra) is preferably 100 μm or less, more preferably 0.01 μm to 30 μm.

  The mounting table 10 is installed on a horizontal base 20, for example, as shown in FIG. A thick insulating plate 21 is interposed between the mounting table 10 and the base 20, and the mounting table 10 is insulated from the base 20. Therefore, the possibility of leakage of electricity from the mounting table 10 or an external current flowing into the mounting table 10 is reduced, and the electric resistance of the separator A can be measured more accurately by the electric resistance measuring device 13.

The contact terminal 11 is made of, for example, a metal such as a composite material (alloy) composed of WC (tungsten carbide / tungsten carbide) and Co (cobalt), which is called hard and good-conducting stainless steel or carbide. Yes. As a raw material, a material that is difficult to be deformed and worn, and has high ease of repetitive operation and high reproducibility is preferable from the viewpoint of simple and reliable evaluation.
For example, as shown in FIG. 3, the contact terminal 11 is connected to a spherical tip portion 11a, a tapered portion 11b that is connected to an upper portion of the tip portion 11a, and gradually increases in diameter upward from the tip portion 11a, and a tapered portion 11b. And a cylindrical portion 11c having a constant diameter. A large diameter portion 11d having a large diameter is formed in a part of the cylindrical portion 11c.
Here, the shape of the tip end portion 11a is preferably spherical or substantially spherical. By adopting such a shape, for example, when contacting the separator A, it is possible to first contact with a point and then gradually increase the contact area along the spherical surface. For this reason, the contact between the contact terminal 11 and the separator A is gradually and gradually performed. Further, the corners of the contact terminals 11 do not hit the separator A. As a result, the possibility that the surface of the separator A is damaged when the contact terminal 11 is in contact is reduced, and the electrical resistance of the separator A can be measured with high accuracy. As a result, the short-circuit load of the separator A tends to be detected with high accuracy.

For example, the tip 11a is formed in a spherical shape with a radius of curvature of 0.05 mm to 4.0 mm, more preferably 1.1 mm to 1.3 mm, or 0.3 mm to 0.5 mm. The upper end portion of the cylindrical portion 11c is fixed to a load cell 30 described later.
Here, the radius of curvature of the tip portion 11a can be appropriately selected according to the electrical insulation of the separator A to be measured.
That is, for example, when the insulation is high due to, for example, the separator A having a large thickness or basis weight, the curvature radius is set to a smaller region (for example, from the viewpoint of avoiding an excessive load applied to the contact terminal while ensuring reproducibility. , 0.3 mm to 0.5 mm). On the other hand, in the case where the insulation is small due to the small thickness or basis weight of the separator A, the curvature radius is set to a larger region (for example, 1.1 mm) from the viewpoint of satisfactorily comparing each measurement object while ensuring reproducibility. To 1.3 mm).
The thickness of the separator A is preferably 1 μm to 100 μm, more preferably from the viewpoint of performing relative comparison of measurement objects with good reproducibility by the load-bearing insulation test apparatus 1 or improving the durability of the contact terminals 11. Is 5 μm to 30 μm.

  For example, as shown in FIG. 1, the moving mechanism 12 supports the contact terminal 11, detects the applied load, and converts the load cell 30 into an electrical signal, a horizontal support plate 31 that supports the load cell 30, and a horizontal support It has a pair of support columns 32 that support and move the plate 31 up and down, and a control unit 33 that controls the vertical movement of the horizontal support plate 31. The support 32 has a built-in drive source such as a motor, and the horizontal support plate 31 can be moved up and down by this drive source.

  The electrical signal of the load detected by the load cell 30 can be output to the control unit 33. The control unit 33 has a monitor function for displaying a load. Further, the control unit 33 can control the vertical movement of the horizontal support plate 31 (load cell 30, contact terminal 11) based on the load.

  The electrical resistance measuring instrument 13 has, for example, a main body 13a and two electric wires 13b. One electric wire 13b is connected to the mounting table 10 from the main body 13a, and the other electric wire 13b is connected to the contact terminal 11 from the main body 13a. The main body 13a can measure the electrical resistance of the separator A sandwiched between the mounting table 10 and the contact terminal 11 via the electric wire 13b. The main body 13a has a monitor and can display the measured value of electrical resistance. The electric wire 13b is made of, for example, a metal strip having excellent flexibility and width. The electric wire 13b may be wound-connected to the side surface of the mounting table 10 or the large diameter portion 11d.

  Next, a load-bearing insulation test method for the separator A using the load-bearing insulation test apparatus 1 configured as described above will be described.

First, as shown in FIG. 1, the separator A is placed on the placing table 10. Next, as shown in FIG. 4, the contact terminal 11 is lowered by the moving mechanism 12, the tip portion 11 a of the contact terminal 11 is brought into contact with the surface of the separator A, and a load is applied to the separator A. At this time, the measurement of the electrical resistance of the separator A is started, and thereafter the measurement is continued while applying a load to the separator.
Here, when the contact terminal is brought into contact with the film surface and a load is applied to the film (after the tip portion 11a of the contact terminal 11 contacts the surface of the separator A), the lowering speed of the contact terminal is, in particular, From the viewpoint of further improving the reproducibility of measurement when a porous material or a flexible material is used as the material of the separator A, preferably 5 μm / min to 100 μm / min, more preferably 5 μm / min to 50 μm / min. It is.
The numerical value of the electrical resistance of the separator A is displayed on the monitor of the main body 13a of the electrical resistance measuring device 13. The load applied to the separator A is detected by the load cell 30 and displayed on the monitor of the control unit 33.

  Then, while confirming the electrical resistance value of the separator A displayed on the main body 13a, the load applied to the separator A is gradually increased, and when the separator A is short-circuited, that is, the insulating property is suddenly broken (insulating property is lost). In the case of an electrical resistance measuring device AD-5518T (manufactured by A & D), the load when the electrical resistance value of the separator A becomes 40 MΩ or less can be detected as a short-circuit load. Thereby, the short circuit load of the separator A is detected, and the insulation performance of the separator A under the load can be confirmed.

A battery positive electrode member or negative electrode member is interposed between the separator A and the contact terminal 11 or the mounting table 10, and the separator A and the battery positive electrode member or negative electrode member are stacked with the contact terminal 11 mounted thereon. It is also possible to measure the electrical resistance of the separator A sandwiched between the table 10.
That is, at least one of the positive electrode member and the negative electrode member is overlapped in the direction in which the active material faces the separator A, and placed between the mounting table 10 and the contact terminal 11 for evaluation. It is effective from the viewpoint of reflecting the influence on the film insulation evaluation (perspective of evaluating the insulation of the separator including compatibility with the electrode).

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It will be apparent to those skilled in the art that various changes or modifications can be made within the scope of the ideas described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs. For example, in the above embodiment, the test object is the separator A, but the present invention can also be applied to an insulation test of other films. Moreover, in the above embodiment, although the shape of the front-end | tip part 11a of the contact terminal 11 was spherical shape, another shape may be sufficient. For example, the tip 11a of the contact terminal 11 may have a shape that makes point contact with the separator A, a shape that makes line contact, or a shape that makes surface contact. In the case of a shape that makes line contact, the distal end portion 11a may have a polyhedral shape that forms a linear ridge at the distal end, for example.

  Next, the present embodiment will be described more specifically with reference to examples and comparative examples. However, the present embodiment is not limited to the following examples unless it exceeds the gist.

[Examples 1 to 4]
The load resistance insulation test apparatus 1 shown in FIG. 1 was configured using the contact terminal 11 having the radius of curvature shown in Table 1 below as the front end portion 11a.
Using the separator shown in Table 1 below as the separator A, a load resistance insulation test was conducted. In addition, the air permeability of the separator A is measured as the time required for 100 ml of air to pass using a Gurley type air permeability meter (G-B2 (trademark) manufactured by Toyo Seiki Co., Ltd.) according to JIS P-8117. The porosity is calculated by cutting a 10 cm × 10 cm square sample, determining its volume (cm ³ ) and mass (g), and the bulk density (g / cm ³ ) of the material.
The material of the contact terminal 11 was cemented carbide, and the descending speed of the contact terminal 11 after the contact terminal 11 was brought into contact with the surface of the separator A was 10 μm / min. The number of samples measured in each example is 20.
The number of samples in which the electrical resistance value of the separator A is 40 MΩ or less under the load shown in Table 1 below is also shown in Table 1 below using an electrical resistance measuring device AD-5518T (manufactured by A & D).

  From the results of Table 1, when a thin film (thickness of about 10 μm) is used as the separator A, it is easier to perform relative comparison between samples while ensuring measurement reproducibility when using the tip 11a having a large curvature radius. I can read.

[Examples 5 to 8]
The load-bearing insulation test apparatus 1 shown in FIG. 1 was configured using the contact terminal 11 having the radius of curvature shown in Tables 2 and 3 as the tip 11a.
The separator shown in Table 2 below was used as the separator A, and a load resistance insulation test was performed. In addition, about the raw material of the contact terminal 11, the descent | fall speed of the contact terminal 11, the number of samples measured in each Example, an electrical resistance measuring apparatus, etc. were performed on the conditions similar to Example 1. FIG. The results are shown in Tables 2 and 3 below.

  From the results of Tables 2 and 3, when using a thick film (thickness of about 20 μm) as the separator A, the tip 11a having a smaller radius of curvature is applied to the tip 11a while ensuring measurement reproducibility. It can be read that the load of the contact terminal 11 can be reduced (the life of the contact terminal 11 can be improved).

It is a schematic diagram which shows the outline of a structure of a load-bearing insulation test apparatus. It is a perspective view of a mounting base. It is a perspective view of a contact terminal. It is explanatory drawing which shows the state which the contact terminal contacted the separator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Load-resistant insulation test apparatus 10 Mounting stand 11 Contact terminal 11a Tip part 12 Moving mechanism 13 Electrical resistance measuring device A Separator

Claims (8)

An apparatus for testing an insulation property of a battery separator under load,
A mounting table for mounting a battery separator ;
A contact terminal for applying a load by contacting the surface of the battery separator on the mounting table;
A moving mechanism capable of moving the contact terminal up and down to vary the load on the battery separator ;
An electrical resistance measuring instrument for measuring the electrical resistance of the battery separator between the mounting table and the contact terminal ;
The load-resistant insulation test apparatus for a battery separator, wherein the tip of the contact terminal has a spherical surface with a radius of curvature of 0.3 mm to 4.0 mm. The load-resistant insulation test apparatus for a battery separator according to claim 1, wherein the tip of the contact terminal is formed in a spherical shape. The load resistance insulation test apparatus for a battery separator according to claim 1 or 2 , wherein the battery separator has a thickness of 1 µm to 100 µm. 4. The load resistance insulation test apparatus for a battery separator according to claim 1 , wherein the surface of the mounting table is polished with an abrasive of # 100 to # 10000. A method for conducting an insulation test of a battery separator under load,
A contact terminal having a spherical surface with a radius of curvature of 0.3 mm to 4.0 mm is brought into contact with the surface of the battery separator mounted on the mounting table, and a load is applied to the battery separator .
While increasing the load gradually, the electric resistance of the battery separator between the mounting table and the contact terminal is measured by an electric resistance measuring device, and the load when the battery separator is short-circuited is detected. A load-bearing insulation test method for battery separators . Lowering speed of the contact terminal when a load is applied to the contact terminal to a battery separator in contact with the battery separator surface, characterized in that it is a 5μm / min~100μm / min, according to claim 5 Load insulation test method for battery separators . The electrical resistance of the battery separator is measured by sandwiching the battery separator and the positive or negative electrode member of the battery between the contact terminal and the mounting table. 5. A load-resistant insulation test method for battery separators according to 5 or 6 . 8. The load insulation test method for a battery separator according to claim 5, wherein the battery separator has a thickness of 1 μm to 100 μm. 9.

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