JP2018085245A - Short circuit test device for battery and short circuit test method for battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a short circuit test device for a battery and a short circuit test method for a battery capable of increasing working safety, and controlling the number of short circuit layers between a cathode active material and an anode active material closely to one layer, and performing accurate safety evaluation.SOLUTION: A short circuit test device for a battery comprises a short circuit occurrence fixture, and the short circuit occurrence fixture comprises a pressing member and a metal cone part arranged at the tip of the pressing member. The pressing member comprises an expansion part expanding more than a bus line of the metal cone part in an outer peripheral direction from a bottom surface part of the metal cone part. Also, the short circuit test method for a battery includes: a process for connecting the battery to a voltage measurement part by using the short circuit test device for a battery; a process for arranging the short circuit occurrence fixture of the short circuit test device for a battery on the battery; a process for causing the short circuit occurrence fixture to move in a battery direction, and for inserting the metal cone part of the short circuit occurrence fixture from a surface of the battery, and for causing the pressing member to press the surface of the battery; and a process for stopping the movement of the short circuit occurrence fixture in the battery direction when the voltage of the battery decreases down to a predetermined voltage.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a battery short-circuit test apparatus and a battery short-circuit test method used for safety evaluation of a battery as an electricity storage device.

  In recent years, with the development of portable electronic devices such as mobile phones and notebook personal computers, and the practical application of electric vehicles, secondary batteries with high capacity and high energy density have been required.

  On the other hand, with the technological innovations such as high capacity and high energy density of the secondary battery as described above, it has become more difficult to ensure its safety. The internal short circuit caused by bending or dendrites cannot be controlled by a safety device or a protection circuit. Therefore, it is very important to evaluate safety in an internal short circuit that cannot be controlled by such a safety device or protection circuit. Conventionally, for example, the following method has been proposed as a method for evaluating safety in an internal short circuit.

  First, in Patent Document 1, a small piece of foreign material is mixed in a location where the positive electrode and the negative electrode in the electrode group face each other, and the mixed portion is pressed by a pressurizing force by a pressurizer, thereby locally disposing an insulating layer interposed between the positive and negative electrodes. An internal short circuit safety evaluation method that breaks down is disclosed.

  Further, in Patent Document 2, in order to prevent the gas generated by the internal short circuit from being discharged to the outside, an electrically conductive member is formed at or near the tip after an adhesive resin layer is formed on the surface of the puncture site. A safety evaluation method is disclosed in which an insulative bar having a thickness of 5 is inserted to a depth at which an internal short circuit occurs to generate an internal short circuit in the battery.

  Furthermore, Japanese Industrial Standard (JIS) C8714 (2007), which is Non-Patent Document 1, discloses a safety test of a unit cell and an assembled battery of a lithium ion storage battery for portable electronic devices, and includes a forced internal of the unit cell. A short-circuit test method has been established. In this forced internal short circuit test method, an electrode body in a charged state is taken out from the battery outer body, the electrode body is unwound, a nickel piece is inserted between the outermost positive electrode active material and the negative electrode active material, and then the electrode This is a test method in which a single layer internal short circuit between the positive electrode active material and the negative electrode active material is generated by re-rolling the body and then pressurizing with a pressurizing jig around the nickel piece insertion portion.

JP 2008-270090 A JP 2010-250954 A

JIS C8714 (2007) Safety test of lithium-ion battery cells and battery packs for portable electronic devices

  The method described in Patent Document 1 and Non-Patent Document 1 is a method of generating a single-layer internal short circuit between the positive electrode active material and the negative electrode active material, but in order to handle a fully charged electrode body by disassembling the battery. , With work hazards. Moreover, since handling of the foreign material small pieces and nickel pieces used in these methods is not an easy work, the work takes time. In that case, the electrolyte in the electrode body decreases during the work due to the volatilization of the solvent, and the internal resistance of the battery increases, so the short-circuit current that occurs at the time of a short circuit also decreases, and accurate safety evaluation may not be possible. .

  On the other hand, although the method described in Patent Document 2 has high work safety, a short-circuit layer between the positive electrode active material and the negative electrode active material is inserted in order to insert an insulating rod having a conductive member at or near the tip. There are cases where the number is not 1 to 2 layers but a multilayer short circuit. This is because the electrode is raised by the gas generated at the time of short circuit, and the number of short circuit layers is increased. Therefore, in the method of Patent Document 2, it is difficult to control the number of short-circuit layers, and it is difficult to always evaluate safety under certain conditions.

  The battery short-circuit test apparatus according to the present invention is a battery short-circuit test apparatus including a short-circuit generating jig, wherein the short-circuit generating jig includes a pressing member and a metal cone portion disposed at a tip of the pressing member. The pressing member includes an overhanging portion that further bulges from the bottom surface portion of the metal cone portion toward the outer periphery of the bus bar of the metal cone portion.

  The battery short-circuit test method of the present invention is a battery short-circuit test method using the battery short-circuit test apparatus of the present invention, wherein the step of connecting the battery to a voltage measuring unit and the battery short-circuit test apparatus Placing the short-circuit generating jig on the battery; moving the short-circuit generating jig toward the battery; and inserting the metal cone portion of the short-circuit generating jig from the surface of the battery. A step of pressing the surface of the battery by the pressing member; and a step of stopping the movement of the short-circuit generating jig in the battery direction when the voltage of the battery drops to a predetermined voltage. .

  According to the present invention, a battery short-circuit test apparatus and a battery having high work safety and capable of controlling the number of short-circuit layers between a positive electrode active material and a negative electrode active material to be close to one layer and enabling accurate safety evaluation. A short circuit test method can be provided.

FIG. 1 is a schematic side view showing an example of a short-circuit generating jig according to an embodiment of the present invention. FIG. 2 is a schematic side view showing another example of the short-circuit generating jig according to the embodiment of the present invention. FIG. 3 is a schematic side view showing another example of the short-circuit generating jig according to the embodiment of the present invention. FIG. 4 is a schematic side view showing another example of the short-circuit generating jig according to the embodiment of the present invention. FIG. 5 is a schematic cross-sectional view of an essential part showing an example of a state where the short-circuit generating jig according to the embodiment of the present invention is inserted into a battery. FIG. 6 is a schematic cross-sectional view of an essential part showing another example of a state where the short-circuit generating jig according to the embodiment of the present invention is inserted into a battery. FIG. 7 is a schematic plan view of a flat lithium ion secondary battery. FIG. 8 is a schematic side view of the short-circuit generating jig according to the first embodiment. FIG. 9 is a schematic external perspective view showing a state immediately before performing a short circuit test of a battery using the short circuit test apparatus of Example 1. FIG. 10 is a schematic side view of the short-circuit generating jig according to the second embodiment. FIG. 11 is a schematic external perspective view showing a state immediately before a battery short-circuit test is performed using the short-circuit test apparatus of Example 2. FIG. 12 is a schematic cross-sectional view of the short-circuit generating jig according to the third embodiment. FIG. 13 is a schematic side view of the short-circuit generating jig of Comparative Example 1. 14 is a schematic external perspective view showing a state immediately before performing a short circuit test of a battery using the short circuit test apparatus of Comparative Example 2. FIG. FIG. 15 is a schematic side view of the short-circuit generating jig of Comparative Example 4.

  Hereinafter, embodiments of the present invention will be described.

(Embodiment of battery short-circuit test device)
The battery short-circuit test apparatus according to the present embodiment includes a short-circuit generating jig, and the short-circuit generating jig includes a pressing member and a metal cone portion disposed at a tip of the pressing member. And a protruding portion that further bulges from the bottom surface portion of the metal cone portion in the outer circumferential direction than the bus bar of the metal cone portion. The bus bar of the metal cone part in this embodiment includes its extension line, and the same applies to the following.

  In the battery short-circuit test apparatus according to the present embodiment, when the metal cone portion of the short-circuit generating jig is inserted into the surface of the battery to generate an internal short-circuit, the protruding portion of the pressing member covers the surface of the battery. It is possible to suppress the increase in the number of short-circuit layers due to the swelling of the battery due to the gas generated when the battery is short-circuited and the accompanying electrode rise, and the number of short-circuit layers between the positive electrode active material and the negative electrode active material can be reduced. It can be controlled to near one layer, and an accurate safety evaluation that unifies the conditions of the short-circuit test becomes possible. Further, by using the battery short-circuit test apparatus according to the present embodiment, unlike the methods described in, for example, the conventional patent document 1 and the non-patent document 1, it is not necessary to handle a fully charged electrode body after disassembling the battery. Therefore, work safety can be improved. Furthermore, since the battery is not disassembled, the electrolyte solvent does not volatilize due to the disassembly of the battery, an increase in the internal resistance of the battery can be suppressed, and an accurate safety evaluation without fluctuations in the conditions of the short-circuit test becomes possible.

  It is preferable that the projecting portion includes a flat portion that is orthogonal to the axis of the metal cone portion. Thereby, the said flat part can press the surface of a battery reliably at the time of a short circuit of a battery. Moreover, it is preferable that the edge part of the said plane part consists of a curved surface. Thereby, a short circuit at the edge portion can be suppressed.

  Further, the overhanging portion may include a spherical portion protruding toward the metal cone portion. This also makes it possible for the spherical portion to press the surface of the battery when the battery is short-circuited, and further to prevent a short-circuit at a portion other than the metal cone portion.

  In the short-circuit generating jig, it is preferable that a spacer in contact with the pressing member is further arranged on a lower outer peripheral portion of the metal cone portion. By using the spacer, when the metal cone part of the short-circuit generating jig is inserted into the surface of the battery and an internal short circuit is generated, it is possible to ensure the sealing property of the embedded part and to prevent an internal short circuit from occurring. Leakage of the generated gas to the outside of the battery can be prevented. Further, by changing the thickness of the spacer, the length of the exposed end portion of the metal cone portion can be easily adjusted. Furthermore, it is preferable that the spacer further bulges from the bottom surface of the metal cone portion toward the outer periphery of the bus bar of the metal cone portion. Thereby, the sealing property of the puncture location can be improved more.

  The spacer is preferably made of a rubber material. Thereby, the adhesiveness with the battery of the said short circuit generation jig | tool can be increased.

  It is preferable that the battery short-circuit test apparatus according to the present embodiment further includes a battery voltage measurement unit and a pressing control unit for the pressing member. Thereby, generation | occurrence | production of the short circuit by the voltage drop of a battery can be grasped | ascertained correctly, and the insertion movement of the said press member can be stopped by it, and it can control to the predetermined | prescribed number of short circuit layers reliably.

  Next, a short-circuit generating jig used in the battery short-circuit test apparatus of the present embodiment will be described in detail with reference to the drawings.

  FIG. 1 is a schematic side view showing an example of a short-circuit generating jig according to the present embodiment. In FIG. 1, the short-circuit generating jig 10 includes a cylindrical pressing member 11 and a conical metal cone portion 12 disposed at the tip of the pressing member 11. The pressing member 11 includes an overhanging portion 14 that bulges further from the bottom surface of the metal cone portion 12 in the outer circumferential direction than the generatrix of the metal cone portion 12, and the overhanging portion 14 includes the metal cone portion 12. A plane portion perpendicular to the shaft 13 is provided. Furthermore, the edge part 15 of the flat part of the overhang | projection part 14 is formed from the curved surface.

  By inserting the metal cone portion 12 of the short-circuit generating jig 10 from the surface of the battery and pressing the battery by the pressing member 11, it is possible to generate a short circuit of the battery safely and reliably.

  FIG. 2 is a schematic side view showing another example of the short-circuit generating jig of the present embodiment. In FIG. 2, the short-circuit generating jig 20 includes a cylindrical pressing member 21 and a conical metal cone portion 22 disposed at the tip of the pressing member 21. The pressing member 21 includes an overhanging portion 24 that further bulges from the bottom surface of the metal cone portion 22 in the outer circumferential direction with respect to the bus bar of the metal cone portion, and the overhanging portion 24 includes the metal cone portion 22. A plane portion perpendicular to the shaft 23 is provided. Further, a disc-shaped spacer 25 that is in contact with the pressing member 21 is disposed on the lower outer peripheral portion of the metal cone portion 22.

  By inserting the metal cone portion 22 of the short-circuit generating jig 20 from the surface of the battery and pressing the battery with the pressing member 21, it is possible to generate a short circuit of the battery safely and reliably. In addition, since the short-circuit generating jig 20 of FIG. 2 includes the spacer 25, it is possible to ensure the sealing performance of the battery insertion portion by the metal cone portion 22.

  FIG. 3 is a schematic side view showing another example of the short-circuit generating jig of the present embodiment. In FIG. 3, the short-circuit generating jig 30 includes a spherical pressing member 31 and a conical metal cone portion 32 disposed at the tip of the pressing member 31. Further, the pressing member 31 includes an overhanging portion 33 that further bulges from the bottom surface portion of the metal cone portion 32 in the outer circumferential direction with respect to the bus bar of the metal cone portion, and the overhang portion 33 is formed of the metal cone portion 32. A spherical portion protruding toward the surface.

  By inserting the metal cone portion 32 of the short-circuit generating jig 30 from the surface of the battery and pressing the battery by the pressing member 31, it is possible to generate a short circuit of the battery safely and reliably.

  FIG. 4 is a schematic side view showing another example of the short-circuit generating jig of the present embodiment. In FIG. 4, the short-circuit generating jig 40 includes a spherical pressing member 41 and a conical metal cone portion 42 disposed at the tip of the pressing member 41. Further, the pressing member 41 includes an overhanging portion 43 that bulges further from the bottom surface of the metal cone portion 42 in the outer circumferential direction than the generatrix of the metal cone portion, and the overhanging portion 43 includes the metal cone portion 42. A spherical portion protruding toward the surface. Further, a disk-shaped spacer 44 that is in contact with the pressing member 41 is disposed on the lower outer peripheral portion of the metal cone portion 42.

  By inserting the metal cone part 42 of the short-circuit generating jig 40 from the surface of the battery and pressing the battery with the pressing member 41, it is possible to generate a short circuit of the battery safely and reliably. In addition, since the short-circuit generating jig 40 of FIG. 4 includes the spacer 44, it is possible to ensure the sealing performance of the battery insertion portion by the metal cone portion 42.

  The material of the metal cone portion shown in FIGS. 1 to 4 is not particularly limited as long as it is a material that can realize an internal short circuit of the battery. However, the material may be a conductive material having an electrical resistivity of 100 Ω · m or less. Preferably, it is most preferable that the electrical resistance of the metal cone part forming the short-circuit part is a conductive material that is equivalent to the internal resistance of the battery. If the electrical resistance of the short-circuited part is equivalent to the internal resistance of the battery, current will easily flow through the short-circuited part, so the amount of heat generated in the short-circuited part will increase, and more dangerous conditions can be reproduced, and accurate safety Evaluation is possible.

  Specific examples of the conductive material used for the metal cone portion include metal materials such as iron, copper, nickel, aluminum, stainless steel, and titanium, and carbonaceous materials that are conductive materials other than metal materials. However, nickel is more preferable from the viewpoint of simulating the mixing of fine metal powder in the battery manufacturing process.

  The shape of the metal cone portion shown in FIGS. 1 to 4 is a conical member, but is not limited to a conical shape, but may be a pyramid shape, but the battery surface is cracked by the corners of the pyramid. Therefore, a conical shape is preferable.

  The optimum height of the metal cone portion varies depending on the type, shape, size, etc. of the battery to be subjected to the short-circuit test, but in the case of the flat lithium ion secondary battery used in the examples described later, it is 0.38 mm. It is preferable that it is 0.61 mm or less.

  The material of the pressing member shown in FIGS. 1 to 4 is not particularly limited as long as it is a rigid material. For example, a ceramic material, a metal material, or the like can be used, but heat dissipation of the battery via the pressing member can be performed. In order to prevent this, a ceramic material having a low thermal conductivity is preferred. Examples of the ceramic material include zirconia, mullite, cordierite, steatite, β-spodumene, aluminum titanate, and zircon.

  Moreover, although the shape of the pressing member shown in FIGS. 1 to 4 is a cylindrical shape or a spherical shape, an overhanging portion that further bulges from the bottom surface portion of the metal cone portion toward the outer periphery of the bus bar of the metal cone portion. If it is a shape which can press a battery, it will not be limited to these shapes, A prismatic shape, a polygonal column shape, an elliptical column shape etc. can be used. In addition, when the shape of the pressing member is other than a spherical shape, the edge portion of the protruding portion that further bulges from the bottom surface portion of the metal cone portion in the outer circumferential direction than the generatrix of the metal cone portion may be a curved surface. preferable. Thereby, a short circuit at the edge portion can be suppressed.

  The spacer material shown in FIGS. 2 and 4 is not particularly limited as long as it is a material having adhesiveness. For example, rubber materials such as fluorine rubber, natural rubber, chloroprene rubber, silicon rubber, and phenol resin are used. Resin-based materials such as acrylic resin, urethane resin, epoxy resin, polyvinyl chloride resin, polyamide resin, polyimide resin, polyacetic acid resin, polystyrene resin, and polyvinyl alcohol resin can be used. In addition, from the viewpoint of suppressing the deformation of the spacer when the battery is pressed by the pressing member, a rubber-based material having adhesion and a resin-based material having rigidity are used in combination, and the spacer made of the rubber-based material is arranged outside. More preferably. Thereby, while being able to suppress a deformation | transformation of a spacer, the adhesiveness of a spacer is also securable.

  Moreover, although the shape of the spacer shown in FIG.2 and FIG.4 was made into the disk shape, if it is a shape which has the same external shape as the bottom face part of the said press member, it will not be limited to a disk shape, a disk shape, an elliptical disk A shape or the like can be used.

  A battery that is a target of a short circuit test using the short circuit test apparatus for a battery according to the present embodiment will be described later.

(Embodiment of battery short-circuit test method)
The battery short-circuit test method of the present embodiment is a battery short-circuit test method using the battery short-circuit test apparatus described in the above-described embodiment. The battery short-circuit test apparatus includes a step of connecting the battery to the voltage measuring unit, and the battery short-circuit test apparatus. Placing the short-circuit generating jig on the battery, moving the short-circuit generating jig toward the battery, and inserting the metal cone portion of the short-circuit generating jig from the surface of the battery. And a step of pressing the surface of the battery by the pressing member, and a step of stopping the movement of the short-circuit generating jig in the battery direction when the voltage of the battery drops to a predetermined voltage.

  Since the battery short-circuit test method of the present embodiment uses the battery short-circuit test apparatus described in the above-described embodiment, the metal cone part of the short-circuit generating jig is inserted into the surface of the battery to cause an internal short circuit. The overhanging portion of the pressing member can press the surface of the battery, and the number of short-circuit layers due to the swelling of the battery due to the gas generated when the battery is short-circuited and the accompanying electrode rise. The increase can be suppressed, the number of short-circuit layers between the positive electrode active material and the negative electrode active material can be controlled to be close to one layer, and an accurate safety evaluation that unifies the conditions of the short-circuit test becomes possible. Further, by using the battery short-circuit test apparatus, unlike the methods described in, for example, the conventional patent document 1 and the non-patent document 1, it is not necessary to handle a fully charged electrode body by disassembling the battery. Can improve the safety. Furthermore, since the battery is not disassembled, the electrolyte solvent does not volatilize due to the disassembly of the battery, an increase in the internal resistance of the battery can be suppressed, and an accurate safety evaluation without fluctuations in the conditions of the short-circuit test becomes possible.

  In the battery short-circuit test method of this embodiment, the battery is preferably disposed on a heat insulating member. Thereby, the heat release when the battery is short-circuited to generate heat can be suppressed, the heat generation state at the time of actual short-circuit can be maintained, and accurate safety evaluation can be performed.

  The material of the heat insulating member is not particularly limited as long as it has high heat insulating properties. For example, inorganic materials such as ceramics, phenol resin, acrylic resin, urethane resin, epoxy resin, polyvinyl chloride resin, polyamide resin, polyimide resin, Organic materials such as polyacetic acid resin, polystyrene resin, and polyvinyl alcohol resin can be used.

  In the battery short-circuit test method of the present embodiment, it is preferable that a temperature measuring element is disposed between the battery and the heat insulating member. That is, by disposing the temperature measuring element under the battery, the temperature measuring element is less affected by the swelling of the battery, and the temperature of the electrode body is more accurately adjusted at a position where the temperature measuring element is not easily separated from the electrode body. It becomes possible to measure. Moreover, by disposing the temperature measuring element on the heat insulating member, it is possible to accurately measure the temperature of the battery in a state where heat dissipation of the battery is suppressed.

  A battery to be subjected to a short-circuit test by the battery short-circuit test method of the present embodiment using the battery short-circuit test apparatus described in the above-described embodiment is formed by stacking a plurality of electrode pairs each including a positive electrode, a separator, and a negative electrode. I have. A typical example of the battery is a lithium ion secondary battery.

  The form of the lithium ion secondary battery is not particularly limited, and may be any one of, for example, a coin shape, a button shape, a sheet shape, a laminated shape, a cylindrical shape, a flat shape, a square shape, a large size used for an electric vehicle, etc. However, the battery short-circuit test method of this embodiment can be applied.

  Here, the thickness of the positive electrode is a, the thickness of the separator is b, the thickness of the negative electrode is c, and both the positive electrode and the negative electrode carry active materials from the surface of the battery and face each other. The thickness from the surface of the battery to the second electrode pair at a location where both of the positive electrode and the negative electrode carry active materials and face each other. It is preferable that the relationship of A + a + b ≦ L <B or A + c + b ≦ L <B is satisfied, where L is the height of the metal cone part exposed from the short-circuit generating jig. Thereby, regardless of the size of the battery, the depth of penetration of the metal cone portion into the battery is mechanically controlled, and the number of short-circuit layers between the positive electrode active material and the negative electrode active material is limited to one layer. it can. As a result, the conditions of the short-circuit test can be made uniform, and accurate safety evaluation can be performed. Further, a two-layer short circuit can be realized by increasing L in a certain range.

  Hereinafter, the above relationship will be described with reference to the drawings. FIG. 5 is a schematic cross-sectional view of an essential part showing an example of a state where the short-circuit generating jig of the present embodiment is inserted into a battery.

  In FIG. 5, the battery 50 includes a positive electrode 51, a separator 52, and a negative electrode 53 from the outside, the first layer electrode pair 55 including the positive electrode 51, a separator 52, and a negative electrode 53. An electrode pair 56 is provided, and a plurality of electrode pairs (not shown) are further provided. The form of the electrode pairs 55 and 56 is not particularly limited, and may be a laminated electrode body in which plate-like electrodes are laminated together with separators, or a wound electrode body in which long electrodes are wound together with separators. Good. Further, in FIG. 5, the tip of the metal cone portion 60 attached to the pressing member 70 of the short-circuit generating jig reaches the surface of the negative electrode 53 of the first-layer electrode pair 55 to realize a one-layer short circuit. Yes.

  In FIG. 5, the thickness of the positive electrode 51 is a, the thickness of the separator 52 is b, the thickness of the negative electrode 53 is c, the thickness from the surface of the battery 50 to the first electrode pair 55 is A, and the battery 50. Since the thickness from the surface of the electrode to the second-layer electrode pair 56 is B and the height of the metal cone portion 60 exposed from the pressing member 70 is L, the relationship of A + a + b ≦ L <B is established. Multilayer short circuit can be mechanically prevented.

  FIG. 6 is a schematic cross-sectional view of an essential part showing another example in which the short-circuit generating jig of the present embodiment is inserted into the battery. In FIG. 6, the battery 50 includes a negative electrode 53, a separator 52, and a positive electrode 51 from the outside, and the first layer electrode pair 57 that includes the negative electrode 53, the separator 52, and the positive electrode 51 from the outside. Since the configuration is the same as that of FIG. 5 except that an electrode pair 58 is provided and a plurality of electrode pairs not shown are provided, detailed description of FIG. 6 is omitted.

  In the battery short-circuit test method of this embodiment, the speed at which the short-circuit generating jig is moved in the direction of the battery and the metal cone portion is inserted from the surface of the battery is not particularly limited, but only the outermost electrode pair. Is preferably 0.5 mm / sec or less, more preferably 0.3 mm / sec or less, and more preferably 0.1 mm / sec. The following is more preferable.

  The mechanism for inserting the short-circuit generating jig into the battery is not particularly limited, but a mechanism that can be operated at a constant insertion speed and can be stopped at any position is preferable, for example, a screw press using a servo motor, A mechanical press, a hydraulic press, an air press, etc. can be used.

  In the battery short-circuit test method of the present embodiment, when the battery voltage drops to a predetermined voltage, the battery voltage drop range in the step of stopping the movement of the short-circuit generating jig in the battery direction, In order to realize a one-layer short circuit of only the outermost electrode pair, it is preferably 0.1 V or less, more preferably 0.07 V or less, and even more preferably 0.05 V or less.

  When evaluating the safety against internal short circuit of the battery using the battery short circuit test method of the present embodiment, for the purpose of evaluating the battery under severe conditions, the short circuit test is performed with the battery fully charged. The environmental temperature is not particularly limited. In general, it is preferable to set a higher temperature that is more severe within the range assumed for the use of a normal battery. For example, JIS C 8714 (2007) Safety test of single battery and assembled battery of lithium ion storage battery for portable electronic devices Then, the upper limit test temperature is set to 45 ° C.

  Also, in battery safety evaluation tests, it is generally possible to check the safety level based on voltage changes, heat generation behavior, battery appearance, etc. by recording voltage, temperature, video by video equipment, etc. it can. Judgment standards for safety level are not unclear depending on test items, standards, etc., but include changes in battery voltage, battery temperature, presence or absence of leakage of electrolyte, presence or absence of smoke, presence or absence of explosion, presence or absence of ignition, etc. Therefore, it is important to judge the safety level from these criteria.

  Further, the number of short-circuit layers of the battery in the battery short-circuit test method of the present embodiment should be confirmed by disassembling the battery after the internal short-circuit test and by a separator hole interposed between the positive electrode active material and the negative electrode active material. Can do. However, in the internal short circuit test, when smoke, rupture, ignition, etc. occur, it may be difficult to determine the number of short circuit layers by combustion or welding of the separator by heat.

The battery for which safety is evaluated by the battery short-circuit test method of the present embodiment is not particularly limited, but the battery capacity (mAh) is determined by the opposing area between the positive electrode mixture layer and the negative electrode mixture layer ( The battery capacity per unit area (hereinafter referred to as “battery capacity per electrode facing area”) obtained by dividing by the area of the part facing through the separator) is less than 3.3 mAh / cm ² . It is suitable for the battery short-circuit test method of this embodiment. Use of a battery with a small battery capacity per electrode facing area makes it easier to release heat generated by the electrode body when the battery is internally short-circuited to other battery members, making it easier to detect temperature changes on the battery surface. Because. However, if the battery capacity per electrode facing area is too small, the energy density of the battery is reduced, the heat generation itself is reduced, and the difference in safety level is not visible. As for the battery for evaluating the above, it is preferable that the battery capacity per electrode facing area is 1 Ah or more.

  The material of the battery exterior body is not limited to aluminum laminate, aluminum, or the like, but in the case of an aluminum laminate member, the metal cone part easily enters and short-circuits. It is a preferable battery form for evaluating safety by a test method.

  On the other hand, when the battery outer body is made of a material having rigidity such as stainless steel, and when the outer body is thick, only the electrode body is taken out of the outer body and the battery short-circuit test method of this embodiment is performed. It is also possible to do this. Thereby, even when the exterior body is thick, it is possible to perform a short circuit test with a low pressing force without disassembling the electrode body.

  Hereinafter, the present invention will be described in detail based on examples. However, the following examples do not limit the present invention.

Example 1
<Preparation of measurement sample>
As a measurement sample, a flat lithium ion secondary battery shown in FIG. 7 was produced as follows.

[Production of positive electrode]
First, 100 parts by mass of LiCoO ₂ (Nippon Kagaku Kogyo Co., Ltd., “C20F”) as a positive electrode active material, 3 parts by mass of acetylene black as a conductive additive, and 3 parts by mass of polyvinylidene fluoride (PVDF) as a binder [ The solid content was supplied as an N-methylpyrrolidone (NMP) solution] was mixed uniformly with NMP as a solvent to prepare a positive electrode mixture-containing paste. Next, the obtained positive electrode mixture-containing paste is applied to both surfaces of a current collector made of an aluminum foil having a thickness of 20 μm so that the coating amount is 23.3 mg / cm ² as the solid content of the positive electrode mixture-containing paste. After intermittent application and drying, calendering is performed, the thickness of the positive electrode mixture layer is adjusted so that the total thickness is 160 μm, and the positive electrode is manufactured by cutting to a length of 485 mm and a width of 56 mm did. Further, a tab was welded to the exposed portion of the aluminum foil of the positive electrode to form a lead portion.

(Production of negative electrode)
Graphite (manufactured by Hitachi Chemical Co., Ltd., “MAGE”) 100 parts by mass, carboxymethyl cellulose (CMC) 1 part by mass (supplied as a 1% by weight aqueous solution) and styrene-butadiene rubber ( SBR) 1.5 parts by mass was mixed with ion-exchanged water having a specific conductivity of 2.0 × 10 ⁵ Ω / cm or more as a solvent to prepare a negative electrode mixture-containing paste. Next, the applied amount of the obtained negative electrode mixture-containing paste is 12.7 mg / cm ² as the solid content of the negative electrode mixture-containing paste on both surfaces of a current collector made of a copper foil having a thickness of 16.5 μm. As described above, after intermittent application and drying, calendering is performed, the thickness of the negative electrode mixture layer is adjusted so that the total thickness is 211 μm, and the negative electrode is cut to have a length of 441 mm and a width of 58 mm. Was made. Further, a tab was welded to the exposed portion of the copper foil of the negative electrode to form a lead portion.

[Preparation of separator]
As the separator, a polyethylene microporous film having a thickness of 25 μm cut into a length of 675 mm and a width of 60.5 mm was prepared.

(Preparation of non-aqueous electrolyte)
A mixed solution is prepared by dissolving 1.0 mol of lithium hexafluorophosphate (LiPF ₆ ) in 1 kg of a mixed solvent of ethylene carbonate (EC) and methyl ethyl carbonate (MEC) in a volume ratio of 1: 3. 2 parts by mass of vinylene carbonate (VC) was further added to 100 parts by mass of the liquid to prepare a non-aqueous electrolyte.

[Battery assembly and charging]
In a dry atmosphere, the positive electrode and the negative electrode were stacked with the separator interposed therebetween, and wound in a spiral shape to produce a wound electrode body. The obtained wound electrode body was further crushed and formed into a flat shape to obtain a flat type wound electrode body. This flat wound electrode body was housed in an outer package made of an aluminum laminate film, sealed after injecting the non-aqueous electrolyte, and a flat lithium ion secondary battery having a battery capacity of 1.2 Ah was produced.

  FIG. 7 shows a schematic plan view of the manufactured flat type lithium ion secondary battery. In FIG. 7, in a flat lithium ion secondary battery 80, a flat wound electrode body and a non-aqueous electrolyte are housed in an outer package 81 made of an aluminum laminate film that is rectangular in plan view. The positive external terminal 82 and the negative external terminal 83 are drawn from the same side of the exterior body 81.

  Finally, the flat lithium ion secondary battery was charged at a constant current and a constant voltage of 4.5 V for 6 hours at a rate of 333 mA (equivalent to 1/3 C), and used as a measurement sample for an internal short circuit test.

<Fabrication of short-circuit generating jig>
Next, the short-circuit generating jig shown in FIG. 8 was produced as follows.

  First, as shown in FIG. 8, a pressing member 101 made of a stainless steel cylindrical body (bottom diameter: 3.4 mm, height: 10 mm) was prepared. Next, a metal cone portion 102 made of a nickel cone (bottom diameter: 3 mm, apex angle 60 degrees) was attached in a 3 mm diameter hole provided at the tip of the pressing member 101.

  Further, a disc-shaped spacer 103a and a spacer 103b having a hole with a diameter of 3 mm at the center were prepared. The spacer 103a was formed of a bakelite cloth base phenolic resin laminate having a diameter of 10 mm and a thickness of 1.5 mm. The spacer 103b was made of Viton rubber having a diameter of 10 mm and a thickness of 0.5 mm. Subsequently, by passing the holes of the spacer 103a and the spacer 103b through the metal cone portion 102, the spacer 103a and the spacer 103b are arranged so as to be in contact with the pressing member 101, the laminated spacer 103 is formed, and a short circuit generating jig is formed. 100 was obtained. The tip length of the metal pyramid portion 102 protruding downward from the bottom surface of the laminated spacer after the laminated spacer 103 was attached was 0.6 mm.

<Production of short-circuit test equipment>
Next, as shown in FIG. 9, the short-circuit generating jig 100 produced as described above is attached to a jig mounting member 90 formed of an aluminum square pillar member having a length of 10 mm, a width of 10 mm, and a height of 50 mm. A short-circuit test apparatus was manufactured by attaching the jig mounting member 90 to which the short-circuit generating jig 100 was mounted to a nail penetration / crush test apparatus (not shown) manufactured by Toyo System Co., Ltd. The produced short-circuit test apparatus further includes a battery voltage measurement unit (not shown) and a pressing control unit (not shown) of the short-circuit generating jig 100.

<Measurement sample layout>
Subsequently, as shown in FIG. 9, the previously produced flat lithium ion secondary battery 80 (hereinafter simply referred to as battery 80) is disposed on a heat insulating member 110 made of a bakelite cloth base phenolic resin laminate. The K thermocouple 120 was attached as a temperature measuring element between the battery 80 and the heat insulating member 110.

<Internal short circuit test>
First, the battery 80 is connected to a voltage measurement unit (not shown) of the short circuit test apparatus. Next, as shown in FIG. 9, the short-circuit generating jig 100 of the short-circuit test apparatus is disposed on the battery 80. Subsequently, under an environment of 25 ° C., the short-circuit generating jig 100 is lowered toward the battery at a speed of 0.1 mm / sec, and the metal cone portion 102 of the short-circuit generating jig 100 is inserted from the surface of the battery 80. At the same time, the pressing member 101 presses the surface of the battery 80 through the laminated spacer 103. Thereafter, when the voltage of the battery 80 decreases by 0.05 V, the descent of the short-circuit generating jig 100 toward the battery is stopped. Then, the maximum temperature of the measurement sample after internal short circuit, the presence or absence of electrolyte leakage, the presence or absence of smoke, the presence or absence of rupture, and the presence or absence of ignition were confirmed.

<Disassembly of battery after internal short circuit test>
Finally, the battery 80 short-circuited internally was disassembled, the separator was taken out, the number of separator layers with holes was counted, and the number of internal short-circuit layers was confirmed.

(Example 2)
<Preparation of measurement sample>
As a measurement sample, the same flat lithium ion secondary battery as in Example 1 was produced.

<Fabrication of short-circuit generating jig>
Next, the short-circuit generating jig shown in FIG. 10 was produced as follows.

  First, as shown in FIG. 10, a pressing member 201 made of a zirconia sphere (diameter: 10 mm) was prepared. Next, a metal cone portion 202 made of a nickel cone (bottom diameter: 3 mm, apex angle 60 degrees) was attached in a 3 mm diameter hole provided at the tip of the pressing member 201.

  Furthermore, disk-shaped spacers 203a and 203b having a hole with a diameter of 3 mm at the center were prepared. The spacer 203a was formed of a bakelite cloth base phenolic resin laminate having a diameter of 10 mm and a thickness of 1.5 mm. The spacer 203b was formed of Viton rubber having a diameter of 10 mm and a thickness of 0.5 mm. Subsequently, by passing the holes of the spacer 203a and the spacer 203b through the metal cone portion 202, the spacer 203a and the spacer 203b are arranged so as to be in contact with the pressing member 201, the laminated spacer 203 is formed, and a short circuit generating jig is formed. 200 was obtained. The tip length of the metal pyramid portion 202 protruding downward from the bottom surface of the laminated spacer after the laminated spacer 203 was attached was 0.6 mm.

<Production of short-circuit test equipment>
Next, as shown in FIG. 11, the short-circuit generating jig 200 produced as described above is attached to a jig mounting member 90 formed of an aluminum square pillar member having a length of 10 mm, a width of 10 mm, and a height of 50 mm. A short-circuit test apparatus was manufactured by attaching the jig mounting member 90 to which the short-circuit generating jig 200 was mounted to a nail penetration / crush test apparatus (not shown) manufactured by Toyo System Co., Ltd. The produced short-circuit test apparatus further includes a battery voltage measurement unit (not shown) and a pressing control unit (not shown) of the short-circuit generating jig 200.

  An internal short circuit test was performed in the same manner as in Example 1 except that the short circuit test apparatus was used, and the battery after the internal short circuit test was disassembled to confirm the number of internal short circuit layers.

(Example 3)
<Preparation of measurement sample>
As a measurement sample, the same flat lithium ion secondary battery as in Example 1 was produced.

<Fabrication of short-circuit generating jig>
Next, the short-circuit test apparatus shown in FIG. 12 was produced as follows.

  First, as shown in FIG. 12, a pressing member 301 made of a stainless steel cylindrical body (bottom diameter: 3 mm, height: 10 mm) was prepared. Next, a nickel-made nail 302 having a length of 20 mm and a diameter of 2 mm was attached to a hole having a diameter of 2 mm provided at the tip of the pressing member 301 and fixed with a screw 304. The nail 302 includes a metal cone portion 302a made of a cone (bottom diameter: 2 mm, apex angle 30 degrees) at an exposed portion from the pressing member 301.

  Furthermore, disk-shaped spacers 303a and 303b having a hole with a diameter of 2 mm at the center were prepared. The spacer 303a was formed of a bakelite cloth base phenolic resin laminate having a diameter of 10 mm and a thickness of 1.5 mm. The spacer 303b was formed of Viton rubber having a diameter of 10 mm and a thickness of 0.5 mm. Subsequently, by passing the holes of the spacer 303a and the spacer 303b through the metal cone portion 302a, the spacer 303a and the spacer 303b are arranged so as to be in contact with the pressing member 301, the laminated spacer 303 is formed, and a short circuit generating jig is formed. 300 was obtained. After attaching the lamination spacer 303, the tip length of the metal cone portion 302a protruding downward from the bottom surface of the lamination spacer was 0.6 mm.

<Production of short-circuit test equipment>
Next, the short-circuit generating device 300 was attached to a nail penetration / crushing test device (not shown) manufactured by Toyo System Co., Ltd., thereby manufacturing a short-circuit testing device. The produced short-circuit test apparatus further includes a battery voltage measurement unit (not shown) and a pressing control unit (not shown) of the short-circuit generating jig 300.

  An internal short circuit test was performed in the same manner as in Example 1 except that the short circuit test apparatus was used, and the battery after the internal short circuit test was disassembled to confirm the number of internal short circuit layers.

(Comparative Example 1)
<Preparation of measurement sample>
As a measurement sample, the same flat lithium ion secondary battery as in Example 1 was produced.

<Fabrication of short-circuit generating jig>
Next, the short-circuit generating jig shown in FIG. 13 was produced as follows.

  First, as shown in FIG. 13, a pressing member 401 made of an aluminum cylindrical body (bottom diameter: 3 mm, height: 50 mm) was prepared. Next, a metal cone portion 402 made of a nickel cone (bottom diameter: 3 mm, height: 2.6 mm, apex angle 60 degrees) is attached to the tip of the pressing member 401, and the short-circuit generating jig 400. Got.

<Production of short-circuit test equipment>
Next, the short-circuit test apparatus was produced by attaching the produced short circuit generating jig 400 to a nail penetration / crush test apparatus (not shown) manufactured by Toyo System Co., Ltd. The produced short-circuit test apparatus further includes a battery voltage measurement unit (not shown) and a pressing control unit (not shown) of the short-circuit generating jig 400.

  An internal short circuit test was performed in the same manner as in Example 1 except that the short circuit test apparatus was used, and the battery after the internal short circuit test was disassembled to confirm the number of internal short circuit layers.

(Comparative Example 2)
<Preparation of measurement sample>
As a measurement sample, the same flat lithium ion secondary battery as in Example 1 was produced.

<Production of short-circuit test equipment>
First, as shown in FIG. 14, a pressing member 101 made of a stainless steel cylindrical body (bottom diameter: 3 mm, height: 10 mm) similar to that in Example 1 was prepared. Next, as shown in FIG. 14, the pressing member 101 prepared above is attached to a jig mounting member 90 formed of a square prism member made of aluminum having a length of 10 mm, a width of 10 mm, and a height of 50 mm. By attaching the jig attaching member 90 to which 101 is attached to a nail penetration / crushing test apparatus (not shown) manufactured by Toyo System Co., Ltd., a short-circuit test apparatus was produced. The produced short-circuit test apparatus further includes a battery voltage measuring unit (not shown) and a pressing control unit (not shown) of the pressing member 101.

  An internal short circuit test was performed in the same manner as in Example 1 except that the short circuit test apparatus was used, and the battery after the internal short circuit test was disassembled to confirm the number of internal short circuit layers.

(Comparative Example 3)
<Preparation of measurement sample>
A measurement sample for a forced internal short-circuit test was prepared as follows in accordance with the method for the safety test of the lithium-ion battery for portable electronic devices as defined in JIS C 8714 (2007).

  First, a flat-type lithium ion secondary battery (hereinafter simply referred to as a battery) similar to that in Example 1 was prepared, and the battery was fixed at a constant current of 4.5 V at 333 mA (rate corresponding to 1/3 C) for 6 hours. Voltage charging was performed to obtain a fully charged state.

  Next, the battery in a fully charged state is disassembled in an environment of a temperature of 25 ° C. and a dew point of −50 ° C., the taken-out electrode body is unwound, and the positive electrode current collector exposed portion exposed on the outermost periphery is placed between the separator , L-shaped nickel pieces (height: 0.2 mm, width: 0.1 mm, side: 1 mm, L-shaped angle: about 90 degrees) so that the corners of the nickel pieces enter the center of the battery. Arranged. Subsequently, the unwound electrode body was rewound, fixed with tape, and marked on the separator at the position of the nickel piece. Furthermore, two polyimide tapes (tape base material thickness: 25 μm, tape width: 10 mm) were attached to the electrode body so that the marking portion is in the center, and the electrode body was put in a polyethylene bag with a chuck, Further, a polyethylene bag was heat-sealed and sealed to obtain a measurement sample. Thereafter, this measurement sample was put in a hermetic laminate pack.

<Production of pressure jig>
First, as a pressure member, a prismatic body made of stainless steel having a length of 10 mm, a width of 10 mm, and a thickness of 30 mm was prepared, and a nitrile rubber plate having a length of 10 mm, a width of 10 mm, and a thickness of 2 mm was attached to the tip of the prismatic body, Further, an acrylic resin plate having a length of 10 mm, a width of 10 mm, and a thickness of 2 mm was attached thereon to produce a pressure jig.

<Production of pressure device>
Next, the pressure jig produced above was attached to the tip of a jig attachment member formed of a square prism member made of aluminum having a length of 10 mm, a width of 10 mm, and a height of 50 mm used in Example 1, and further added A pressurizing device was produced by attaching the jig mounting member with the pressure jig attached to a nail penetration / crushing test device (not shown) manufactured by Toyo System Co., Ltd. The produced pressurizing device further includes a battery voltage measuring unit (not shown) and a pressurizing control unit (not shown) of the pressurizing jig.

<Measurement sample layout>
The measurement sample (polyethylene bag-containing electrode body) is taken out from the sealed laminate pack, the measurement sample is placed on a heat insulating member made of a bakelite cloth base material phenolic resin laminate, and the measurement sample and the heat insulating member are arranged. A K thermocouple was attached as a temperature measuring element.

<Internal short circuit test>
First, the said measurement sample is connected to the voltage measurement part (not shown) of a pressurization apparatus. Next, a pressurizing device is disposed on the marking portion of the measurement sample. Subsequently, in an environment of 25 ° C., the pressure device was lowered toward the measurement sample at a speed of 0.1 mm / sec, and the marking portion of the measurement sample was pressurized to generate an internal short circuit. Thereafter, when the voltage of the measurement sample decreased by 0.05 V due to an internal short circuit, the descent of the pressurizing device was stopped. Thereafter, the maximum temperature of the measurement sample after the internal short circuit, the presence or absence of leakage of the electrolyte, the presence or absence of smoke, the presence or absence of rupture and the presence or absence of ignition were confirmed.

<Disassembly of measurement sample after internal short circuit test>
Finally, the measurement sample (electrode body) short-circuited internally was disassembled, the separator was taken out, the number of separator layers with holes was counted, and the number of internal short-circuit layers was confirmed.

(Comparative Example 4)
<Preparation of measurement sample>
As a measurement sample, the same flat lithium ion secondary battery as in Example 1 was produced.

<Fabrication of short-circuit generating jig>
Next, the short circuit generator shown in FIG. 15 was produced as follows.

  First, as shown in FIG. 15, an insulating pressing member 501 made of a ceramic cylinder (bottom diameter: 3 mm, height: 70 mm) was prepared. Next, after processing the tip of the pressing member 501 so that it has a conical shape with an angle of 60 degrees, a portion of 1 mm from the tip is cut, and a metal made of a nickel cone having a height of 1 mm and an angle of 60 degrees The cone part 502 was attached and the short circuit generation jig | tool 500 was obtained. In FIG. 15, the pressing member 501 does not bulge outward from the extended line 503 of the bus bar of the metal cone portion 502.

<Production of short-circuit test equipment>
Next, the short-circuit test apparatus was produced by attaching the produced short-circuit generating jig 500 to a nail penetration / crush test apparatus (not shown) manufactured by Toyo System Co., Ltd. The produced short-circuit test apparatus further includes a battery voltage measurement unit (not shown) and a pressing control unit (not shown) of the short-circuit generating jig 500.

  An internal short circuit test was performed in the same manner as in Example 1 except that the short circuit test apparatus was used, and the battery after the internal short circuit test was disassembled to confirm the number of internal short circuit layers.

  Table 1 shows the maximum temperature of the measurement samples after the short circuit in Examples 1 to 3 and Comparative Examples 1 to 4, the presence or absence of electrolyte leakage, the presence or absence of smoke, the presence or absence of explosion, the presence or absence of ignition, and the number of short-circuit layers. Show. The test start temperature of the measurement sample is 25 ° C.

  In Examples 1 to 3 using the short circuit test apparatus according to the embodiment of the present invention, it was confirmed that the temperature of the measurement sample was increased due to the internal short circuit, but in the measurement sample, leakage, smoke generation, bursting, and ignition were observed. There wasn't. Moreover, all the short circuit layers of Examples 1-3 were one layer. This is presumably because the height of the tip of the metal cone part of the short-circuit generating jig used was appropriate.

  In Comparative Example 1, no leakage, smoke, rupture, or ignition of the measurement sample due to the internal short circuit was confirmed, but the temperature increase of the measurement sample due to the internal short circuit was large. Moreover, the number of short-circuit layers in Comparative Example 1 was three. This is because the pressing member of the short-circuit generating jig used did not have an overhanging part, so that the surface of the measurement sample could not be pressed after the occurrence of a short circuit, and the number of short circuits increased due to the rising of the electrode, or This is probably because the insertion depth of the short-circuit generating jig could not be controlled and the short-circuit generating jig reached the third layer.

  In Comparative Example 2, leakage, smoke generation, bursting, and ignition of the measurement sample due to an internal short circuit were all confirmed, the temperature increase of the measurement sample exceeded 500 ° C., and the calorific value was very large. For this reason, it was difficult to disassemble the measurement sample after the short circuit, and the number of short circuit layers could not be confirmed. This is probably because the short-circuit test apparatus used in Comparative Example 2 did not include the metal cone portion, and thus the number of short-circuit layers could not be controlled, and the above phenomenon was reached.

  In Comparative Example 3, smoke, rupture, and ignition of the measurement sample due to internal short circuit were not confirmed, and the number of short circuit layers was one layer, but the temperature increase of the measurement sample due to internal short circuit could not be confirmed, and the measurement sample Leakage was confirmed. This is because, in Comparative Example 3, the electrode body was taken out from the exterior body, so the electrolyte in the electrode body decreased due to volatilization of the solvent, the internal resistance of the measurement sample increased, and the short circuit current generated at the time of the short circuit also decreased. It is considered that the temperature rise of the measurement sample did not occur. Moreover, in the comparative example 3, it was the test method accompanied by the danger of taking out an electrode body from an exterior body.

  In Comparative Example 4, no leakage, smoke, rupture, or ignition of the measurement sample due to the internal short circuit was confirmed, but the temperature increase of the measurement sample due to the internal short circuit was large. Moreover, the number of short-circuit layers in Comparative Example 4 was three. This is because the pressing member of the short-circuit generating jig used did not have an overhanging portion that bulges outward from the extension of the bus bar of the metal cone portion, so that the surface of the measurement sample may be pressed after the occurrence of the short-circuit. This is probably because the number of short circuits has increased due to the rising of the electrodes, or the insertion depth of the short circuit generating jig cannot be controlled and the short circuit generating jig has reached the third layer.

  By using the battery short-circuit test apparatus of the present invention, the battery is highly safe in operation, and the number of short-circuit layers between the positive electrode active material and the negative electrode active material can be controlled to be close to one, and accurate safety evaluation can be performed. Therefore, the present invention is highly useful in industry in battery research and development, technology development, etc., and is very useful in industry.

10, 20, 30, 40 Short-circuit generating jig 11, 21, 31, 41 Press member 12, 22, 32, 42 Metal cone portion 13, 23 Shaft 14, 24, 33, 43 Overhang portion 15 Edge portion 25, 44 Spacer 50 Battery 51 Positive electrode 52 Separator 53 Negative electrode 55, 56, 57, 58 Electrode pair 60 Metal cone portion 70 Press member 80 Flat lithium ion secondary battery 81 Exterior body 82 Positive electrode external terminal 83 Negative electrode external terminal 90 Jig mounting member 100, 200 Short-circuit generating jig 101, 201 Press member 102, 202 Metal cone part 103, 203 Laminated spacer 103a, 103b, 203a, 203b Spacer 110 Thermal insulation member 120 K Thermocouple 300 Short-circuit generating jig 301 Press member 302 Nail 302a Metal cone part 303 Laminate spacer 303a, 303b Over 400 short circuit jig 401 pressing member 402 metal cone portion 500 short circuit jig 501 pressing member 502 metal cone section

Claims (12)

A short-circuit test apparatus for a battery including a short-circuit generating jig,
The short-circuit generating jig includes a pressing member, and a metal cone portion disposed at a tip of the pressing member,
The short circuit test apparatus for a battery, wherein the pressing member includes a projecting portion that further bulges from the bottom surface portion of the metal cone portion toward the outer periphery of the bus bar of the metal cone portion.   The battery short-circuit test apparatus according to claim 1, wherein the projecting portion includes a flat portion that is orthogonal to the axis of the metal cone portion.   The short circuit test apparatus for a battery according to claim 2, wherein an edge portion of the flat portion is a curved surface.   The short circuit test apparatus for a battery according to claim 1, wherein the projecting portion includes a spherical portion projecting toward the metal cone portion.   The battery short-circuit test apparatus according to claim 1, wherein a spacer in contact with the pressing member is further disposed on a lower outer peripheral portion of the metal cone portion.   The battery short-circuit test apparatus according to claim 5, wherein the spacer further bulges from a bottom surface portion of the metal cone portion in an outer circumferential direction with respect to a bus bar of the metal cone portion.   The battery short-circuit testing apparatus according to claim 5 or 6, wherein the spacer is made of a rubber-based material.   The battery short-circuit test apparatus according to claim 1, further comprising a battery voltage measurement unit and a pressing control unit for the pressing member. A battery short-circuit test method using the battery short-circuit test apparatus according to any one of claims 1 to 8,
Connecting the battery to the voltage measurement unit;
Arranging the short-circuit generating jig of the battery short-circuit test apparatus on the battery;
Moving the short-circuit generating jig in the battery direction, piercing the metal cone part of the short-circuit generating jig from the surface of the battery and pressing the surface of the battery with the pressing member;
And a step of stopping the movement of the short-circuit generating jig in the battery direction when the voltage of the battery drops to a predetermined voltage.   The said battery is a short circuit test method of the battery of Claim 9 arrange | positioned on a heat insulation member.   The battery short-circuit test method according to claim 10, wherein a temperature measuring element is disposed between the battery and the heat insulating member. The battery includes a plurality of electrode pairs including a positive electrode, a separator, and a negative electrode,
The thickness of the positive electrode is a, the thickness of the separator is b, the thickness of the negative electrode is c, and from the surface of the battery, both the positive electrode and the negative electrode carry active materials and face each other. A thickness to the electrode pair of the layer is A, B is a thickness from the surface of the battery to the electrode pair of the second layer at the place where both the positive electrode and the negative electrode carry the active material and face each other, When the height of the metal cone exposed from the short-circuit generating jig is L,
The battery short-circuit test method according to claim 9, wherein a relationship of A + a + b ≦ L <B or A + c + b ≦ L <B is established.

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