Withstand voltage measuring device of battery diaphragm

Abstract

The utility model relates to a withstand voltage measuring device of a battery diaphragm, which comprises a first withstand voltage measuring end and a second withstand voltage measuring end opposite to the first withstand voltage measuring end, and a first metal foil and a second metal foil are sequentially arranged between the first withstand voltage measuring end and the second withstand voltage measuring end from the first withstand voltage measuring end. The first metal foil and the second metal foil are each independently octagonal or more, circular or quasi-circular, and when the cross-sectional area of the tip of the first withstand voltage measurement end is S1, the area of the first metal foil is S metal 1, the area of the diaphragm to be measured is S diaphragm, and the area of the second metal foil is S metal 2, S1 is the cross-sectional area of the tip of the first withstand voltage measurement end, S metal 1 is the area of the diaphragm to be measured, and S metal 2 is the area of the diaphragm to be measured. The following formulae (1) and (2) are satisfied: S metal 1 > = S1 (1), S metal 2 > = S diaphragm (2).

Description

Technical Field

[0001] The utility model relates to a device for measuring the breakdown voltage of a battery separator. Background Art

[0002] In the structure of a battery (including a battery cell) such as a lithium battery, the separator is one of the important components, which is disposed between the positive and negative electrodes of the battery and plays a role in characteristics such as the capacity and safety of the battery. Therefore, when measuring the physical properties of the separator, the ultimate breakdown voltage is an important index parameter. In terms of the prior art, for example, as shown in Figure 1 , the following method is used to confirm that the ultimate breakdown voltage of the battery separator is qualified: The battery separator 103' is disposed between the copper plate 105' and the copper rod 101' perpendicular thereto without gaps and pressed tightly, and then, in a completely static state, a withstand voltage tester W is used to break down through a high voltage to determine its maximum withstand voltage value, for example, 1000 V or more. Summary of the Utility Model

[0003] However, in terms of the above device configuration, since tip discharge occurs during high-voltage breakdown, the following problems exist: Residues are generated between the copper plate and the separator and between the copper rod and the separator and adhere to the surfaces of the copper plate and the copper rod. Through analysis, it is known that the components of such residues mainly come from copper. It is considered that: Since the thickness of the separator is very thin, generally only about ten μm to dozens of μm, even the attachment of fine residues may damage the separator during pressing before measurement, having a huge adverse impact on the measurement result of the ultimate breakdown voltage. For example, during the initial measurement, since the surfaces of the copper rod and the copper plate are clean and there is no attachment of residues, the measurement result of the good-quality separator is, for example, 1000 V or more as described above. However, after continuously performing the same measurement without cleaning the copper rod and the copper plate, residues caused by high-voltage discharge adhere to the surfaces of the copper plate and the copper rod. In this case, even for a good-quality separator, its ultimate breakdown voltage measurement result drops significantly to several hundred V, seriously affecting the measurement accuracy (accuracy) during continuous measurement and also having an adverse impact on the equipment. Currently, as a means to solve the above problems, after measuring several separators, the surfaces of the copper plate and the copper rod are polished, for example, polished successively with sandpapers of 2000 mesh, 3000 mesh, etc., and then, after confirming that it is wiped clean, the measurement of the ultimate breakdown voltage of the subsequent separators is continued. However, since such an operation is a manual operation and polishing itself also wears the surfaces of the copper plate and the copper rod, affecting the surface flatness, if residues caused by polishing or incomplete polishing occur, it will also have an adverse impact on the subsequent ultimate breakdown voltage measurement accuracy and the equipment life.

[0004] The present utility model is completed in view of the above problems existing in the prior art, and the purpose is to provide a withstand voltage measuring device that can balance the measurement accuracy and operation efficiency during continuous measurement and has excellent equipment life.

[0005] The inventors of the present utility model conducted repeated in-depth studies to achieve the above purpose. As a result, they accidentally found that when aluminum foils with a specific shape are provided between the copper rod and the diaphragm and between the diaphragm and the copper plate, the ultimate withstand voltage value can be stably measured, and it will not have an adverse effect on the measurement result, and the measurement accuracy is also high. The above phenomena and results were accidentally discovered by the inventors of the present utility model this time. Then, the inventors of the present utility model tried to compare by respectively providing a metal foil between the copper rod and the diaphragm and between the diaphragm and the copper plate, and thus compared with the case where no metal foil is provided and the copper rod and the copper plate are not polished. It should be noted that for the withstand voltage measurement, 30 diaphragm samples are continuously measured as one experiment, and both the experiment with the metal foil provided and the experiment without the metal foil provided are measured 5 times respectively. Before each experiment measurement, the copper rod and the copper plate are polished. During the measurement of 30 diaphragm samples in each experiment, no treatment is done to the copper rod and the copper plate. In addition, the metal foil used is an aluminum foil with a flat surface and a uniform thickness of 15 μm, and the aluminum foil is cut into an octagon and configured in such a way that two aluminum foils fully separate between the diaphragm and the copper rod and between the diaphragm and the copper plate respectively. In addition, all the diaphragm samples used are confirmed to be good products before measurement. The measurement conditions are as follows.

[0006] Measuring equipment: TOS5200 withstand voltage tester manufactured by Kikusui Electronics Industry Co., Ltd., Japan

[0007] Set voltage: 2000V

[0008] Voltage rise time: 10s

[0009] Test time: 2s

[0010] Upper limit current: 60mA

[0011] It can be seen from the measurement results of the experiment that: as Figure 2 shown, in the case of the previous situation, that is, Experiments 1 - 5 without the metal foil provided ( Figure 2 the upper table in Figure 2 ), in each experiment, after measuring about 15 - 20 diaphragm samples, residues caused by high-voltage discharge will occur, resulting in large deviations in subsequent measurements, and the ultimate voltage value is lower than 1000V, and accurate measurement cannot be performed. In contrast, for Experiments 6 - 10 with the metal foil provided ( Figure 2 the lower table in Figure 2 ), the measurement was stably and accurately performed in all 5 experiments, and the measurement deviation between 30 diaphragm samples in each experiment was small, and the ultimate withstand voltage value was stable at about 1200V.

[0012] The inventors of the present utility model found through the above content that by respectively arranging metal foils with specific shapes between the copper rod and the diaphragm, and between the diaphragm and the copper plate, residues are generated between the diaphragm (i.e., the measured diaphragm) and each metal foil, which can avoid the adhesion of residues on the copper rod and the copper plate. More specifically, when continuously performing the withstand voltage measurement of the diaphragm (i.e., the ultimate withstand voltage measurement), they are arranged in sequence according to the order of the copper rod, the first metal foil, the diaphragm (i.e., the measured diaphragm), the second metal foil, and the copper plate. At the same time, the first metal foil and the second metal foil are set to the specific shapes described later. In this way, it is considered that since the contact impedance between each metal foil and the diaphragm is greater than the contact impedance between each metal foil and the copper rod and the copper plate respectively, when they are connected to the positive and negative voltage output ports of the withstand voltage tester and measured, residues caused by high-voltage discharge will be generated between each metal foil and the diaphragm. In other words, the first metal foil and the second metal foil respectively replace the copper rod and the copper plate and become the front ends of high-voltage discharge. As a result, when continuously performing the withstand voltage measurement, only by replacing the metal foil, the equipment can be maintained to ensure the equipment life, and the measurement accuracy during continuous measurement can be ensured. Moreover, the replacement of such metal foils is simple, without the need for complicated and high-precision polishing operations, etc., which can greatly improve the operation efficiency of the withstand voltage measurement.

[0013] The present utility model is completed based on the above discovery, and its main idea is as follows.

[0014] [1] A device for measuring the withstand voltage of a battery diaphragm, characterized in that it includes a first withstand voltage measurement terminal and a second withstand voltage measurement terminal arranged opposite to it,

[0015] Between the above-mentioned first withstand voltage measurement terminal and the above-mentioned second withstand voltage measurement terminal, a first metal foil and a second metal foil are arranged in sequence starting from the above-mentioned first withstand voltage measurement terminal,

[0016] The above-mentioned first metal foil and the above-mentioned second metal foil are respectively independently octagon or above, circular or quasi-circular,

[0017] When setting the cross-sectional area of the front end of the above-mentioned first withstand voltage measurement terminal as S 1 , setting the area of the above-mentioned first metal foil as S 金属1 , setting the area of the measured diaphragm as S 隔膜 , and setting the area of the above-mentioned second metal foil as S 金属2 , the following formulas (1) and (2) are satisfied:

[0018] S 金属1 ≥S 1 (1)

[0019] S 金属2 ≥S 隔膜(2).

[0020] [2] The voltage withstand measurement device for a battery separator according to [1], characterized in that the thicknesses of the first metal foil and the second metal foil are independently 10 to 20 μm.

[0021] [3] The voltage withstand measurement device for a battery separator according to [1] or [2], characterized in that the following formula (3) is further satisfied:

[0022] S 隔膜 ≥S 金属1 (3).

[0023] [4] The voltage withstand measurement device for a battery separator according to any one of [1] to [3], characterized in that the first metal foil and the second metal foil are independently any one of aluminum, iron, copper, silver, and gold.

[0024] Effect of the utility model

[0025] According to the present utility model, it is possible to provide a voltage withstand measurement device that can balance the measurement accuracy and operation efficiency during continuous measurement and has excellent equipment life. Description of the drawings

[0026] Figure 1 is a schematic diagram showing a schematic view of a conventional voltage withstand measurement device for a battery separator.

[0027] Figure 2 is a chart for explaining the comparison between the case where metal foils are respectively provided between the copper rod and the separator and between the separator and the copper plate and the case where no metal foil is provided.

[0028] Figure 3 is a schematic diagram showing an example of a voltage withstand measurement device for a battery separator according to an embodiment of the present utility model. Detailed implementation manners

[0029] Hereinafter, the voltage withstand measurement device for the battery separator of the present utility model will be described in detail with reference to the accompanying drawings. The embodiments described below are illustrative, merely representing general or specific examples, and can take various forms. The numerical values, shapes, materials, constituent elements, arrangement positions and connection forms of the constituent elements, steps, order of steps, etc. shown in the following embodiments are all examples and are not intended to limit the present utility model. In addition, among the constituent elements of the following embodiments, the constituent elements not described in the independent claims are described as optional constituent elements. Furthermore, the respective drawings disclosed in this specification are only schematic illustrations in principle. That is, the dimensional ratios on the drawings are not necessarily the same as the actual dimensional ratios, and the dimensional ratios are not necessarily the same among the respective drawings. In each figure, substantially the same constituent elements are denoted by the same reference numerals, and repeated descriptions are omitted or simplified.

[0030] (Embodiment)

[0031] Hereinafter, the voltage withstand measurement device for the battery separator of one embodiment of the present utility model will be described in detail.

[0032] The voltage withstand measurement device for the battery separator of this embodiment includes a first voltage withstand measurement terminal and a second voltage withstand measurement terminal arranged opposite thereto.

[0033] Between the above-mentioned first voltage withstand measurement terminal and the second voltage withstand measurement terminal, a first metal foil and a second metal foil are sequentially arranged starting from the first voltage withstand measurement terminal.

[0034] The above-mentioned first metal foil and the second metal foil are each independently octagon or more, circular or quasi-circular.

[0035] When the cross-sectional area of the front end of the above-mentioned first voltage withstand measurement terminal is set as S 1 , the area of the above-mentioned first metal foil is set as S 金属1 , the area of the separator to be measured is set as S 隔膜 , and the area of the above-mentioned second metal foil is set as S 金属2 , the following formulas (1) and (2) are satisfied:

[0036] S 金属1 ≥S 1 (1)

[0037] S 金属2 ≥S 隔膜 (2).

[0038] Figure 3 A schematic diagram showing an example of the voltage withstand measurement device for the battery separator of one embodiment of the present utility model is shown. As Figure 3As shown, the withstand voltage measuring device 10 of the battery separator includes: a copper rod 101 as the first withstand voltage measurement terminal; and a copper plate 105 as the second withstand voltage measurement terminal disposed opposite thereto. Here, in Figure 3 the copper rod 101 is disposed substantially perpendicular to the copper plate 105. Between the copper rod 101 and the copper plate 105, a first metal foil 102 and a second metal foil 104 are sequentially disposed starting from the copper rod 101. The first metal foil 102 and the second metal foil 104 are each independently octagon or above, circular or quasi-circular. When the cross-sectional area of the measurement front end 101a of the copper rod 101 is set as S 1 , the area of the first metal foil 102 is set as S 金属1 , the area of the diaphragm 103 to be measured is set as S 隔膜 , and the area of the second metal foil 104 is set as S 金属2 , the following formulas (1) and (2) are satisfied:

[0039] S 金属1 ≥S 1 (1)

[0040] S 金属2 ≥S 隔膜 (2).

[0041] It should be noted that in the following description, taking the copper rod ( Figure 3 the copper rod 101 in Figure 3 ) as the first withstand voltage measurement terminal and the copper plate (

[0042] the copper plate 105 in ) as the second withstand voltage measurement terminal as an example, the front end of the first withstand voltage measurement terminal is the measurement front end 101a of the copper rod 101.By adopting the above configuration, that is, arranging them in the order of copper rod 101, first metal foil 102, diaphragm under test 103, second metal foil 104, and copper plate 105, and setting the first metal foil 102 and the second metal foil 104 to specific shapes that satisfy the above formulas (1) and (2), when performing a withstand voltage test after pressing them tightly and leaving them completely stationary, the first metal foil 102 and the second metal foil 104 respectively replace the copper rod 101 (more specifically, the measurement front end 101a of the copper rod 101) and the copper plate 105 to become the front ends of high-voltage discharge. As a result, residues caused by high-voltage discharge will be generated between the first metal foil 102 and the diaphragm under test 103, and between the second metal foil 104 and the diaphragm under test 103. In this way, when continuously performing a withstand voltage test, by only replacing the first metal foil 102 and the second metal foil 104, the residues caused by high-voltage discharge adhere to the surfaces of the first metal foil 102 and the second metal foil 104, which can avoid the residues from adhering to the surfaces of the copper rod 101 and the copper plate 105, and ensure the measurement accuracy during continuous measurement. In addition, compared with the polishing operation of the copper rod 101 and the copper plate 105, replacing the first metal foil 102 and the second metal foil 104 is more convenient, greatly improving the operation efficiency of the withstand voltage test. Here, the copper rod 101 and the copper plate 105 are respectively connected to the positive and negative voltage output ports of the withstand voltage tester through leads. In addition, in the present utility model, "substantially perpendicular" means a range deviating by ±10° from the completely perpendicular state of 90°.

[0043] Regarding the shapes of the first metal foil 102 and the second metal foil 104, as described above, they are respectively octagon or above, circular or quasi-circular independently. If the first metal foil 102 and the second metal foil 104 are in a shape with less than eight sides, each corner becomes sharp, that is, the angle becomes smaller, and it is easy to generate burrs during cutting, leading to tip discharge and affecting the accuracy of the measurement result. Therefore, the shapes of the first metal foil 102 and the second metal foil 104 are respectively set to octagon or above. In addition, considering aspects such as the stability of measurement and the convenience of cutting and processing, the first metal foil 102 and the second metal foil 104 are preferably axisymmetric shapes, for example, a regular octagon in the case of an octagon. In addition, since the shape edges of a circle or a quasi-circle are arc-shaped, it is not easy to cause tip discharge, etc., so the measurement can also be performed with good accuracy. Here, a quasi-circle only needs to have an arc-shaped edge, for example, an ellipse can be cited. Figure 3 Examples in which the first metal foil 102 and the second metal foil 104 are respectively substantially circular are shown. The first metal foil 102 and the second metal foil 104 can be in the same shape or in different shapes.

[0044] Regarding the areas of the first metal foil 102 and the second metal foil 104, as described above, the above formulas (1) and (2) are satisfied, that is, the area of the first metal foil 102 is greater than or equal to the cross-sectional area of the measurement front end 101a of the copper rod 101, which is the front end of the first withstand voltage measurement terminal, and the area of the second metal foil 104 is greater than or equal to the area of the diaphragm 103 to be measured. In other words, the first metal foil 102 is arranged in such a way as to avoid contact between the measurement front end 101a of the copper rod 101 and the diaphragm 103 to be measured, and the second metal foil 104 is arranged in such a way as to avoid contact between the copper plate 105 and the diaphragm 103 to be measured. Additionally, of course, there is no contact between the first metal foil 102 and the second metal foil 104, that is, they are in an insulating state. If the area of the first metal foil 102 is smaller than the cross-sectional area of the measurement front end 101a of the copper rod 101, it is possible that the measurement front end 101a of the copper rod 101 contacts the diaphragm 103 to be measured, resulting in a discharge phenomenon between the two during the withstand voltage measurement, thereby affecting the measurement accuracy and causing residues to adhere to the measurement front end 101a of the copper rod 101. Similarly, if the area of the second metal foil 104 is smaller than the area of the diaphragm 103 to be measured, it is possible that the copper plate 105 contacts the diaphragm 103 to be measured, resulting in a discharge phenomenon between the two during the withstand voltage measurement, thereby affecting the measurement accuracy and causing residues to adhere to the copper plate 105. From the above viewpoints, it is more preferable that the area of the first metal foil 102 is greater than the cross-sectional area of the measurement front end 101a of the copper rod 101, and the area of the second metal foil 104 is greater than the area of the diaphragm 103 to be measured.

[0045] In addition, in order to further reliably ensure the areas of the first metal foil 102 and the second metal foil 104 and avoid mutual contact, it can also be further set that: the minimum diameter of the first metal foil 102 is greater than the maximum diameter of the cross-section of the measurement front end 101a of the copper rod 101, and the minimum diameter of the second metal foil 104 is greater than the maximum diameter of the diaphragm 103 to be measured. Here, the so-called minimum diameter, for example, in the case of an ellipse, is the smallest diameter passing through the center of the ellipse, and in the case of a polygon, is the diameter of its inscribed circle; the so-called maximum diameter, for example, in the case of an ellipse, is the largest diameter passing through the center of the ellipse, and in the case of a polygon, is the diameter of its circumscribed circle. For a circle, both the minimum diameter and the maximum diameter are its diameter.

[0046] In addition, in order to prevent contact between the first metal foil 102 and the second metal foil 104 and perform the withstand voltage measurement more reliably, it is preferable to further satisfy the following formula (3):

[0047] S 隔膜 ≥S 金属1 (3)

[0048] That is, the area of the diaphragm 103 to be measured is equal to or larger than the area of the first metal foil 102. In addition, in order to more reliably perform the withstand voltage measurement, it is more preferable that the area of the diaphragm 103 to be measured is larger than the area of the first metal foil 102. Further, it may be further set that the minimum diameter of the diaphragm 103 to be measured is larger than the maximum diameter of the first metal foil 102.

[0049] In addition, the thicknesses of the first metal foil 102 and the second metal foil 104 are preferably 10 to 20 μm independently. If the thickness is less than 10 μm, it may not be able to protect the copper rod 101 and the copper plate 105 well, and the limit withstand voltage measurement accuracy during continuous measurement may decrease. If the thickness is greater than 20 μm, it may be easy to generate burrs when cutting the first metal foil 102 and the second metal foil 104 due to the excessive thickness, resulting in tip discharge and affecting the measurement accuracy. Therefore, the thicknesses of the first metal foil 102 and the second metal foil 104 are set to 10 to 20 μm respectively. The thicknesses of the first metal foil 102 and the second metal foil 104 may also be set to 12 μm or more, 14 μm or more, or 18 μm or less, 16 μm or less respectively.

[0050] In addition, regarding the materials of the first metal foil 102 and the second metal foil 104, any commonly used metal may be used, such as aluminum, iron, copper, silver, gold, etc. Considering the convenience of acquisition and processing, etc., aluminum foil is preferred.

[0051] Embodiment

[0052] Next, a solution and its effects of the present utility model will be further specifically described through embodiments. However, the conditions in the embodiments are one condition example adopted for confirming the feasibility and effects of the present utility model, and the present utility model is not limited to this one condition example. As long as it does not deviate from the gist of the present utility model and achieves the purpose of the present utility model, the present utility model can adopt various conditions.

[0053] 1. "Metal Foil Shape Test"

[0054] As Figure 3The metal foil is configured as follows: a copper rod as the first withstand voltage measurement terminal, the first metal foil, the separator, the second metal foil, and a copper plate as the second withstand voltage measurement terminal are arranged in this order. Each metal foil is set to be an aluminum foil with a thickness of 15 μm, a flat surface, and a uniform thickness. Additionally, the areas are set as follows: the area of the first metal foil is greater than or equal to the cross-sectional area of the front end of the first withstand voltage measurement terminal (i.e., the measurement front end of the copper rod), the area of the second metal foil is greater than or equal to the area of the separator to be measured, and the area of the separator to be measured is greater than or equal to the area of the first metal foil. The aluminum foil is cut into regular polygons with the number of sides shown in Table 1, and the withstand voltage of 30 separator samples is measured respectively. All separator samples are confirmed to be good products before measurement. In addition, to ensure the accuracy of the measurement results, the copper rod and the copper plate are polished before measurement with different numbers of sides. It should be noted that the "number of sides of the aluminum foil" recorded in Table 1 represents the number of sides of the first metal foil and the second metal foil. The measurement conditions are as follows.

[0055] Measuring equipment: TOS5200 withstand voltage tester manufactured by Kikusui Electronics Industry Co., Ltd., Japan

[0056] Set voltage: 2000V

[0057] Voltage rise time: 10s

[0058] Test time: 2s

[0059] Upper limit current: 60mA

[0060] The case where the measured ultimate voltage value is lower than 1000V is regarded as unqualified. The case where there are more than 2 unqualified products among 30 separator samples is evaluated as poor measurement accuracy. The measurement results are shown in Table 1.

[0061] Table 1

[0062] Test No. Number of aluminum foil edges Proportion of non - conforming numbers Classification 1 3 15 / 30 Comparative example 2 4 13 / 30 Comparative example 3 6 5 / 30 Comparative example 4 8 0 / 30 Inventive example 5 10 0 / 30 Inventive example 6 12 0 / 30 Inventive example 7 Round 0 / 30 Inventive example

[0063] The underlines indicate that it is outside the scope of the present invention.

[0064] As can be seen from the results shown in Table 1, for Comparative Examples 1 to 3 with a small number of sides of the aluminum foil, specifically less than eight sides, each corner becomes sharp, and it is easy to generate cutting burrs, leading to tip discharge. As a result, the measurement accuracy deteriorates.

[0065] In contrast, for Invention Examples 4 to 7 with the number of sides of the aluminum foil being eight or more or circular, the measurement accuracy is excellent.

[0066] 2. "Metal Foil Thickness Test"

[0067] As Figure 3The metal foil is configured as follows, i.e., it is configured in the order of a copper rod as the first withstand voltage measurement terminal, the first metal foil, the separator, the second metal foil, and a copper plate as the second withstand voltage measurement terminal. Each metal foil is set to be a regular octagonal aluminum foil with a flat surface and a uniform thickness. In addition, the areas are set as follows: the area of the first metal foil is not less than the cross-sectional area of the front end of the first withstand voltage measurement terminal (i.e., the measurement front end of the copper rod), the area of the second metal foil is not less than the area of the separator to be measured, and the area of the separator to be measured is not less than the area of the first metal foil. The thicknesses of the aluminum foils serving as the first and second metal foils are varied under the conditions shown in Table 2, and the withstand voltage measurements are respectively performed on 30 separator samples. All separator samples are confirmed to be good products before the measurement. In addition, in order to ensure the accuracy of the measurement results, the copper rod and the copper plate are polished before the measurement at different thicknesses. It should be noted that the "aluminum foil thickness" recorded in Table 2 represents the thicknesses of the first and second metal foils. The measurement conditions are as described in the above-mentioned "1. 《Metal Foil Shape Test》".

[0068] The case where the measured ultimate voltage value is lower than 1000 V is regarded as unqualified. The case where there are more than 2 unqualified products among 30 separator samples is evaluated as poor measurement accuracy. The measurement results are shown in Table 2.

[0069] Table 2

[0070] Test No. Aluminum foil thickness Proportion of non - conforming numbers Classification 8 5μm 21 / 30 Comparative example 9 8μm 11 / 30 Comparative example 10 10μm 2 / 30 Inventive example 11 15μm 0 / 30 Inventive example 12 20μm 1 / 30 Inventive example 13 25μm 8 / 30 Comparative example 14 30μm 15 / 30 Comparative example

[0071] The underlines indicate that they are outside the scope of the present invention.

[0072] As can be seen from the results shown in Table 2, for Comparative Examples 8 and 9 where the thickness of the aluminum foil is too small, since the copper rod and the copper plate cannot be well protected, the measurement accuracy becomes poor. For Comparative Examples 13 and 14 where the thickness of the aluminum foil is too large, since burrs are easily generated during cutting, resulting in tip discharge, the measurement accuracy becomes poor.

[0073] In contrast, for Invention Examples 10 to 12 where the thickness of the aluminum foil is appropriate, the measurement accuracy is excellent. In particular, when the thickness of the aluminum foil is 15 μm, the number of unqualified products becomes 0, and the measurement accuracy is even more excellent.

[0074] 3. 《Tests on Different Materials and Thicknesses of Metal Foil》

[0075] As Figure 3The metal foils are arranged in such a way that they are arranged in the order of a copper rod as the first withstand voltage measurement terminal, a first metal foil, a separator, a second metal foil, and a copper plate as the second withstand voltage measurement terminal. Each metal foil is set to be a regular octagon with a flat surface and a uniform thickness. In addition, the areas are set as follows: the area of the first metal foil is not less than the cross-sectional area of the front end of the first withstand voltage measurement terminal (i.e., the measurement front end of the copper rod), the area of the second metal foil is not less than the area of the separator to be measured, and the area of the separator to be measured is not less than the area of the first metal foil. The materials and thicknesses of the first metal foil and the second metal foil are changed under the conditions shown in Table 3, and the withstand voltage measurements are respectively carried out on 30 separator samples. All separator samples are confirmed to be good products before the measurement. In addition, in order to ensure the accuracy of the measurement results, the copper rod and the copper plate are polished before the measurement of different materials and thicknesses. It should be noted that the "metal foil material" recorded in Table 3 represents the materials of the first metal foil and the second metal foil, and the "metal foil thickness" recorded in Table 3 represents the thicknesses of the first metal foil and the second metal foil. The measurement conditions are as described in the above "1. 《Metal Foil Shape Test》".

[0076] The case where the measured ultimate voltage value is lower than 1000 V is regarded as unqualified. The case where there are more than 2 unqualified products among 30 separator samples is evaluated as poor measurement accuracy. The measurement results are shown in Table 3.

[0077] Table 3

[0078]

[0079] As can be seen from the results shown in Table 3, for Invention Examples 15 to 21, when the metal foil material is any one of iron, copper, silver, and gold and the thickness is 10 to 20 μm, the measurement accuracy is excellent.

[0080] The present utility model has been described above based on the currently preferred embodiments, but the disclosed content should not be construed in a limiting manner. Various deformations and changes will be obvious to those skilled in the art in the technical field to which the present utility model belongs by reading the above disclosure. Therefore, without departing from the true spirit and scope of the present utility model, the appended claims should be construed to include all deformations and changes.

[0081] Industrial Applicability

[0082] According to the present utility model, it is possible to provide a withstand voltage measurement device that can balance the measurement accuracy and operation efficiency during continuous measurement and has excellent equipment life.

[0083] Explanation of Symbols

[0084] 101 Copper rod (first withstand voltage measurement terminal)

[0085] 101a measurement front end

[0086] 102 First metal foil

[0087] 103 Diaphragm under test

[0088] 104 Second metal foil

[0089] 105 Copper plate (second breakdown voltage measurement terminal)

Claims

1. A battery separator withstand voltage measuring device, characterized in that: comprising a first withstand voltage measurement terminal and a second withstand voltage measurement terminal arranged opposite thereto, A first metal foil and a second metal foil are arranged in order from the first withstand voltage measurement end between the first withstand voltage measurement end and the second withstand voltage measurement end. The first metal foil and the second metal foil are independently octagonal or larger, circular or quasi-circular, The cross-sectional area of ​​the tip of the first withstand voltage measuring end is set as S1, and the area of ​​the first metal foil is set as S 金属1 , the area of ​​the diaphragm to be measured is set to S 隔膜 , the area of ​​the second metal foil is set to S 金属2 When , the following equations (1) and (2) are satisfied: S 金属1 ≥S1 (1) S 金属2 ≥S 隔膜 (2)。 2. The withstand voltage measuring device for a battery separator according to claim 1, characterized in that: The thickness of the first metal foil and the second metal foil is independently 10 to 20 μm.

3. The withstand voltage measuring device for a battery separator according to claim 1 or 2, characterized in that: Further satisfying the following formula (3): S 隔膜 ≥S 金属1 (3)。 4. The withstand voltage measuring device for a battery separator according to claim 1 or 2, characterized in that: The first metal foil and the second metal foil are independently any one of aluminum, iron, copper, silver, and gold.

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