JP2015072266A - Safety testing method and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a safety evaluation testing method for a safety evaluation test of an electricity storage device and its testing device, especially for a peg test.SOLUTION: A safety evaluation testing method prepares a test container which stores inert fluid, fully immerses an electricity storage device into the inert fluid by placing the electricity storage device in the test container, and performs a predetermined safety evaluation test for the electricity storage device.

Description

The present invention relates to a safety evaluation test method and a test apparatus for performing a safety evaluation test of a power storage device, and particularly to a nail penetration test.

In recent years, batteries with high energy density, such as lithium ion batteries, which occupy an important corner of power storage devices, have been actively developed because high output can be obtained. However, when an electrical short circuit occurs inside a lithium ion battery, depending on the structure, sudden heat generation causes the internal organic electrolyte (particularly the solvent and electrolyte) to decompose and evaporate, generating harmful gases, It can be one of the causes of explosions and flames, and there are still problems with safety.

For this reason, in batteries with high energy density, such as lithium ion batteries, and power storage devices, the surface of the metal nail can be obtained by piercing the battery with a metal nail and penetrating the positive and negative electrodes and the insulating partition wall (separator) all at once. In some cases, the positive electrode and the negative electrode are brought into contact with each other at the same time, and a state simulating an internal short circuit is generated to verify the safety. This test is commonly called a “nail penetration test”, and during the test, heat generation, smoke generation / ignition, and rupture may occur. In other words, the current “nail penetration test” is intended to confirm that there is no heat generation, smoke, ignition, or explosion that can lead to an accident when an electrical short circuit occurs inside the battery for various reasons. As a safety evaluation test.

Therefore, from the viewpoint of preventing human and property damage during the test, perform the test in a chamber with a high pressure resistance and explosion proof structure that can withstand a large internal pressure, or fill the sealed chamber with inert argon gas, Methods such as testing with suppression of ignition have been taken. (Patent Document 3)

International Publication WO2006-088021 International Publication No. WO2011-004506 JP 2011-003513 A

As described above, a large battery with a high energy density in recent years has a possibility of explosion and ignition in a test for verifying safety, and is a room or box type chamber that can withstand an explosion. They used rooms with equipment that could handle them and sealed chambers. For batteries that are so large that the existing chamber cannot be used, it is necessary to create a new chamber, or in the case of a completely new sample battery or a very large battery whose destructive force cannot be predicted, the chamber should be Since there is a possibility of destruction, there is a current situation that tests are being conducted in a vast location such as an outdoor blast experiment facility on the site of the fireworks factory.

Also, if a large battery is used for the test, it may explode after the test and the contents may be scattered. If the battery does not explode or burn, an analysis that is possible by analyzing the debris It was impossible to verify what kind of reaction was caused by the cause or the cause by the combustion.

Below, specific problems found in the patent literature will be verified.
The technology relating to the safety evaluation test method and apparatus disclosed in Patent Document 1 has the following problems.
1) For example, when performing a nail penetration test, which is an important test item in the safety evaluation test, a test machine that generates a heavy load load is boothed against a large battery with a large battery, that is, a strong outer container. ("Chamber" as referred to in the present invention). Therefore, there is a problem that the test cannot be performed unless a large-volume booth is prepared. In addition, because the load tester is housed in the booth, the battery is damaged during the test, the contents are scattered, and every time a burning flaw occurs, the load tester becomes dirty in addition to the chamber. Also occurs. In the case of severe dirt, the load tester has a movable part and a sliding part, and therefore there is also a problem that a failure is likely to occur.

2) In addition, there is a problem that the booth must be designed and constructed in an airtight pressure-resistant structure because a large amount of gas generated from the lithium ion battery must be captured only by the booth during the safety evaluation test.

In Patent Document 2, a temperature sensor (here, a thermocouple) is specified in the nail, and is specified as a device that can easily measure a temperature change in the vicinity of a heat source during a nail penetration test. At this time, the electrolytic solution and the positive electrode / negative electrode active material cause a chemical reaction due to a rapid temperature change and a combustion reaction, and some product is generated, but these sampling and analysis are not taken into consideration.

In addition, if the contents explode during the test and the contents are scattered, the temperature history remains, but it is not possible to investigate what kind of chemical reaction caused the explosion / combustion. It was difficult in the test.

On the other hand, in Patent Document 3, a chamber (a test container referred to in Patent Document 3) for installing a power storage device inside and performing a predetermined safety evaluation test, and a movable head of a load load tester installed outside the chamber are used. An airtight seal is provided on the lid of the chamber so that the attached nail can pierce the electricity storage device installed inside the chamber and has airtightness. A buffer tank that communicates with the gas tank; a gas bag that communicates with the buffer tank; a decompression means for decompressing the air in the chamber and the buffer tank to a predetermined pressure before the predetermined safety evaluation test; Before the safety evaluation test, an inert gas having a predetermined pressure is provided in the chamber and the buffer tank that are decompressed by the decompression means. The inert gas is supplied until replacement, and after the predetermined safety evaluation test is completed, the gas generated from the electricity storage device accumulated in the chamber and the buffer tank is supplied to the gas bag. In order to transfer, an inert gas supply means for supplying a predetermined amount of inert gas to the chamber, and an analyzer for analyzing gas generated from the electricity storage device transferred to the gas bag Although it is a safety evaluation test device characterized by having it, if the battery breaks during the test in the chamber and the contents scatter or burns and generates soot, the load tester can move The problem that the head and the chamber became dirty remained.

In addition, even if the conditions are maintained to avoid ignition and explosion due to the effect of filling with inert gas, it is necessary to prepare a pressure-resistant sealed container in case of an explosion and a corresponding large tank to collect the reaction products as gas. So we had to build a large facility.

One object of the present invention is to store a power storage device and to perform a safety evaluation test, so that a high-pressure-resistant and large-capacity test container is not required, and the storage device is prevented from being damaged or ignited. It is an object of the present invention to provide a safety evaluation test method and a test apparatus for the generated chemical substance that can be collected in a liquid state before being gasified and can be analyzed. Specifically, since sampling can be performed in a liquid state before the occurrence of abnormal high-temperature vaporization or before it occurs, it is possible and easy to secure a sampling amount of at least a milligram unit sufficient for analysis.

Hereinafter, the power storage device is referred to as a general battery because it mainly describes the nail penetration test among the safety tests of the power storage device, but it is synonymous.

In a conventional nail penetration test, a metal nail is simply pierced into a battery under test, causing an electrical short circuit inside the battery. In this test, in order to measure the calorific value and temperature change at the time of a short circuit, in many cases, a temperature sensor such as a thermocouple has been attached to the surface of the battery under test or the base of a nail (not shown). If it is installed inside the battery under test and the temperature change in the vicinity of the internal short-circuit occurrence site is observed, the sensor itself, which is generally composed of a conductor, may become a short-circuit source. Since the internal structure and state of the battery will also be changed, the location of the temperature sensor is limited to the surface of the battery, etc., immediately after the occurrence of a short circuit at the location of the short circuit that is directly related to the magnitude of the accident and the destructive force. It was extremely difficult to obtain information on temperature changes.

In addition, if the battery begins to deform, such as swelling, in the event of an abnormality, the temperature sensor attached to the battery surface will be increasingly separated from the heat source and heat generation location (internal short circuit location). Continuous measurement cannot be performed. Further, when a serious battery destruction occurs, the temperature sensor is often destroyed.

The present invention has been created in view of the above problems. The present invention is specifically listed below. The present invention
Prepare a test vessel to store the inert liquid,
Immerse it completely in an inert liquid by placing the electricity storage device in a test container,
Provided is a safety evaluation test method for performing a predetermined safety evaluation test for an electric storage device.

The predetermined safety evaluation test may be any one of a nail penetration test, an overcharge test, and a heating test.

Further, the safety test method of the present invention includes:
The predetermined safety evaluation test for the electricity storage device is a nail penetration test,
A safety evaluation test method for puncturing with a nail having a sharp tip with respect to an electricity storage device that is completely immersed in an inert liquid stored in the test container,
The nail forms a vertical hole opened from the nail root to the vicinity of the tip of the nail, and at least a temperature sensor is disposed in the vertical hole,
In addition, a through-hole that communicates the outside of the nail and the vertical hole is formed near the tip of the vertical hole, and at least a part of the contents of the electricity storage device can be collected through the through-hole when puncturing.

The inert liquid is Fluorinert, Galden, or silicone oil.

In addition, other safety testing devices of the present invention are:
The predetermined safety evaluation test for the electricity storage device is a nail penetration test in which an electricity storage device completely immersed in an inert liquid stored in a test container is punctured with a nail with a sharp tip,
The nail is
A vertical hole opened from the nail root to the vicinity of the tip of the nail is provided, and at least a temperature sensor is disposed in the vertical hole,
Further, a through hole that communicates the outside of the nail and the vertical hole may be formed near the tip of the vertical hole.

In addition, another safety test apparatus according to the present invention is configured such that a predetermined safety evaluation test for the power storage device is performed with a nail having a pointed tip with respect to the power storage device that is completely immersed in an inert liquid stored in a test container. A nail penetration test,
The nail is
A vertical hole is formed from the nail root to the vicinity of the tip of the nail,
Further, a through hole that communicates the outside of the nail and the vertical hole may be formed near the tip of the vertical hole.

Further, in the safety test device of the present invention, when the predetermined safety evaluation test is an overcharge test, a power storage installed inside the test container from an overcharge test power source installed outside the test container. A current supply terminal that can supply current to the positive and negative terminals of the device is provided in the test container.

Further, in the safety test apparatus of the present invention, when the predetermined safety evaluation test is a heating test, the power storage device installed inside the test container is supplied from a heating test power supply installed outside the test container. A current supply terminal capable of supplying a current to a heater placed in the vicinity may be provided in the test container.

In the safety test apparatus of the present invention, the predetermined safety evaluation test for the electricity storage device is performed by a nail that is pierced with a nail having a sharp tip with respect to the electricity storage device that is completely immersed in an inert liquid stored in a test container. A stab test,
The nail is
Two or more vertical holes opened from the nail root to the vicinity of the tip of the nail are provided, and the depths of the vertical holes are different from each other, and at least one temperature sensor is disposed in each vertical hole,
Moreover, the structure by which the through-hole which connects the exterior of a nail and this vertical hole was opened in the tip vicinity of each said vertical hole is illustrated.

In another safety test apparatus of the present invention, the predetermined safety evaluation test for the power storage device is performed by puncturing with a nail having a sharp tip with respect to the power storage device that is completely immersed in the inert liquid stored in the test container. A nail penetration test,
The nail is
A vertical hole opened from the nail root to the vicinity of the tip of the nail is provided, and at least two temperature sensors are disposed in the vertical hole,
Moreover, the structure by which the through-hole which connects the exterior of a nail and this vertical hole was opened in the tip vicinity of this vertical hole may be sufficient.

Furthermore, in another safety test apparatus of the present invention, the predetermined safety evaluation test for the power storage device is performed by puncturing with a nail having a sharp tip with respect to the power storage device that is completely immersed in the inert liquid stored in the test container. A nail penetration test,
The nail is
Two or more vertical holes opened from the nail root to the vicinity of the tip of the nail are provided, and at least one temperature sensor is disposed in each of the vertical holes,
Further, a configuration is also conceivable in which each through hole that communicates the outside of the nail and the vertical hole is formed in the vicinity of the tip of each vertical hole.

The temperature sensor is preferably a thermocouple, a thermistor, or a resistance temperature detector.

The specific configuration of the present invention has been described above, but the basic concept of the present invention is described below.
In order to achieve this object, the present inventors have continued to measure the temperature change during the battery test more faithfully by suppressing the oxidation / combustion reaction that causes destruction or ignition during the nail penetration test. As a method, it was considered to suppress the penetration of air (oxygen) into the nail-pierced part (internal short-circuit occurrence place) as an ignition source. Because, before the battery breaks down, specifically, just before less than 1 second, ignition occurs, but the three elements of ignition are
Oxygen: Anywhere air ignition source: Heat generated by internal short circuit and red hot point fuel generated by short circuit current Fuel: If the electrolyte is an organic combustible material, even if one of these can be removed, no ignition will occur Of course, it does not progress to an explosion. Hereinafter, the background to this consideration will be described.

Naturally, it is impossible to remove the electrolytic solution inside the battery. In addition, heat generated by a short circuit cannot be eliminated in view of the original purpose of a test for generating an electrical short circuit for a power storage device that has voltage and stores energy in the state of electrical energy. Therefore, it was concluded that the remaining factor, air, must be removed.

So far, specifically, in the nail penetration test, conventionally, a method of replacing with inert argon gas or nitrogen gas has been employed (see Patent Document 3). In addition, considering the explosive limit in the test environment, it is conceivable to carry out under reduced pressure, but if a nail penetration test is performed, the electrolyte will lower the boiling point depending on the external pressure from the hole where the nail was inserted. In combination with this, it is induced by temperature rise due to short-circuit current heat generation, rapidly evaporating and scattering, making it difficult to maintain the reduced pressure, and the internal resistance of the test battery starts to rise, so the original heat generation behavior does not continue, so the internal An abnormal condition due to abnormal heat generation in the short circuit test cannot be displayed.

In addition, the electrolyte that has started to vaporize may ignite or ignite for some reason (for example, the ejection speed becomes too high and triggers frictional ignition between the gas and the metal of the battery container). There was a problem.

As a result of intensive studies, the present inventors have provided a test method for performing a nail penetration test in an inert liquid as a method for shielding the supply of air, particularly oxygen, in liquid form.
The inert liquid referred to in the present invention has a high dielectric strength and low chemical reactivity, specifically, has at least an insulation property up to the maximum voltage that can be generated by the test battery system, and Any material may be used as long as it does not have chemical reactivity with various materials used and reaction products thereof. For example, fluorinate, galden, and silicone oil were used.

Furthermore, in order to facilitate the measurement of the temperature of the short-circuit occurrence part (maximum temperature reached and temperature change) that is closely related to the magnitude of the expected destructive force, the outer frame and temperature of the nail that is made of a metal with high hardness It consists of sensors. Specifically, a vertical hole for inserting the temperature sensor in the axial direction is drilled in the center of the outer frame with the outer shape of the nail from the nail head to near the tip, and the temperature sensor is inserted into the vertical hole. A tip with a hot spot was brought close to the bottom of the hole to make a nail penetration tester with a temperature measuring function. As a result, it is possible to accurately observe even an internal short-circuit phenomenon with a mild temperature change, and even if the battery is deformed, temperature measurement can be performed near the heating point without shifting or detaching the temperature measuring point. The accuracy of temperature change measurement is maintained.

In addition, a mixture of exuded electrolyte and inert liquid can be sampled by drilling a horizontal hole (through hole) at the tip of the nail. When the temperature rises, chemical changes that have occurred in the electrolyte and the electrochemical reaction products in an abnormal voltage state associated with overcharging, which is one of the safety tests, ooze out into an inert liquid in the absence of oxygen. By utilizing the incompatibility with an inert liquid as the liquid sample, it is fortunate that extraction separation is easy, and chemical analysis becomes possible. In addition, there is no difference in the case of suction collection instead of spontaneous collection, and the same effect can be expected. Specifically, a suction machine is attached to the base of a nail that has a horizontal hole in the innermost part of the perforation, and the electrolyte is collected with a pump that has excellent small-volume suction control capability.

As typical pumps, liquid transport pumps such as tube pumps, solder suction machines, and bimol pumps (sold by Meadow Industries) are preferably used.

Further, the nail in the nail penetration test may be filled with a fluid material having high thermal conductivity in the vicinity of the tip of the vertical hole where the temperature sensor is disposed and between the temperature sensor and the inner wall of the vertical hole.

The temperature sensor may not be sufficiently in contact with the bottom surface when inserted into the vertical hole. In such a case, the temperature sensor has a tendency to decrease its thermal responsiveness. On the other hand, if a fluid material with high thermal conductivity such as silver paste is filled in the vicinity of the tip of the vertical hole, even if the contact state to the bottom surface of the vertical hole is somewhat bad, the thermal response is about the same as that of contact It was found that sex (sensitivity) can be obtained. This leads to an improvement in the degree of freedom of the insertion depth of the temperature sensor. As a result, the assembly work of the nail and the apparatus is facilitated, the working time is shortened, the number of defective products is reduced, and the cost reduction effect is recognized.

Further, the nail forms a vertical hole opened from the nail root portion to the vicinity of the tip of the nail, and when placing at least the temperature sensor in the vertical hole, an insertion port for inserting the temperature sensor into the vertical hole is provided as a side wall of the nail. You may have.

In this case, since the insertion port for the vertical hole of the temperature sensor is provided on the side wall of the nail, the temperature sensor can be inserted with the base of the nail attached to the base, so that the nail can be pushed in with a strong pressure. Become.

The nail is provided with two or more vertical holes opened from the root of the nail to the vicinity of the tip of the nail, and the depth of the vertical holes is different from each other. At least one temperature sensor is included in each vertical hole. Are inserted in the side walls of the nail, and the position of the insertion port from the nail root corresponds to the depth of each vertical hole. It may be opened differently.

Although the same as the above in that the temperature sensor insertion port is provided in the side wall of the nail, the nail has a plurality of vertical holes. At this time, the height from each insertion port to the position of the tip of the vertical hole is substantially the same. Therefore, the position of the insertion port of the temperature sensor can be known according to the depth of the vertical hole, and individual information such as which is a deep hole and which is a shallow hole can be determined by the opening position when inserting. As a result, erroneous insertion can be prevented.

Further, the nail preferably has an insertion port for inserting the temperature sensor in the vertical hole in the side wall of the nail, and the insertion port opens obliquely downward from the nail root toward the nail tip.

When the insertion port passes through the side wall in a direction orthogonal to the vertical hole in the nail (a case of a horizontal hole), there may be a problem when inserting a large amount of temperature sensors. Specifically, when the temperature sensor is inserted into the vertical hole in the nail, the contact point is sharply sharp at an angle of 90 degrees, which may damage the temperature sensor. Considering such a case, it was found here that the temperature sensor is hardly damaged by opening a horizontal hole up to the insertion opening at an angle, and the insertion can be performed at a gentle angle and can be inserted in a short time. In particular, when the vertical hole is narrow and the nail is thick, this improvement in workability is remarkable, which is advantageous for mass production.

As described above, it is preferable that a through hole that communicates the outside of the nail and the vertical hole is formed in the vicinity of the tip of each vertical hole. In addition, the following explanation is given with a sheath thermocouple, but other temperature sensors, for example, a temperature measuring device having a predetermined size (a size that can be mounted in a vertical hole of a nail) and performance (resistance to withstand the highest temperature). A resistor or a thermistor may be used.

In the present invention, since the temperature sensor is inserted into the nail, the temperature of the internal short-circuit portion of the battery under test in the nail penetration test can be directly measured.

On the other hand, a horizontal hole (through hole) opened near the tip of the vertical hole is suitable for sampling a product generated by a thermal reaction at the time of a short circuit from the inside of the battery. This is because the electrolyte solution can be sequentially collected from the tip of the nail that has reached the vicinity of the reaction, and the change with time of the product due to the reaction can be traced.

Also, when performed in an inert liquid with a larger heat capacity than air, heat generated by forced internal short-circuiting due to nail penetration and overcharge tests that force energy from the outside is absorbed and dispersed, and compared with tests in air. Thus, the temperature of the battery itself does not increase so much. In addition, since rapid oxidation reaction, that is, ignition, does not occur because oxygen is shielded, ignition and smoke are unlikely to occur even with dangerous batteries, and only changes due to temperature changes, chemical gas generation, etc. are precise. It was possible to observe the heat generation behavior due to short circuit current and the progress of chemical reactions (exothermic reaction and endothermic reaction), and until now, there was only an analysis method for temperature change by the temperature sensor placed inside the nail. This is an indispensable information source.

In addition, the contents of the battery collected from the through-hole opened at the tip of the nail can be collected from the beginning of the chemical reaction, and there is no situation such as inability to collect due to battery combustion, gasification / volume expansion due to high temperature, and thermal denaturation. Since it can be recovered in liquid form, it is considered to be an indispensable collection method for obtaining more useful knowledge.

On the other hand, since the heat capacity of the inert liquid is larger than that of air, the temperature change of the battery during the test is slowed down, and the difference in temperature rise behavior between the high-risk battery and the non-hazardous battery is reduced. It became the action which raised the necessity to grasp the subtle difference which was not understood by the temperature change on the surface by grasping the temperature change near the short circuit point accurately by the temperature sensor inside the nail.

It is a longitudinal cross-sectional view of the nail-shaped test tool used for the nail penetration test which has arrange | positioned the temperature sensor inside a nail. It is a test conceptual diagram of the safety test device in the present invention. It is a longitudinal cross-sectional view of the nail-like test tool used for the nail penetration test which arrange | positions a temperature sensor inside the nail used for the safety test apparatus of this invention, and also has a penetration pit which takes a sample from the inside of an electrical storage device. It is a longitudinal cross-sectional view of the nail-shaped test tool used for the nail penetration test which also has a through-hole which samples from the inside of the electrical storage device used for the safety test apparatus of this invention. It is a longitudinal cross-sectional view of the nail-like test tool used for the nail penetration test which arrange | positions a temperature sensor inside the nail used for the safety test apparatus of this invention, and also has a penetration pit which takes a sample from the inside of an electrical storage device. It is a longitudinal cross-sectional view of the nail-shaped test tool used for the nail penetration test which has arrange | positioned the temperature sensor inside the nail used for the safety test apparatus of this invention. It is a longitudinal cross-sectional view of the nail-shaped test tool used for the nail penetration test which has arrange | positioned the temperature sensor inside the nail used for the safety test apparatus of this invention. It is a longitudinal cross-sectional view of the nail-like test tool used for the nail penetration test which arrange | positions a temperature sensor inside the nail used for the safety test apparatus of this invention, and also has a penetration pit which takes a sample from the inside of an electrical storage device. It is a longitudinal cross-sectional view of the nail-shaped test tool used for the nail penetration test which also has a through-hole which samples from the inside of the electrical storage device used for the safety test apparatus of this invention. It is a test conceptual diagram of a safety test device as a conventional example. 4 is a test tool in which a fluid material having high thermal conductivity is filled in a vertical hole into which a thermocouple is inserted into the nail of the safety test apparatus of FIG. 3. FIG. 4 is a test device in which a thermocouple insertion port is provided in the upper side wall of the nail of the safety test apparatus of FIG. 3. 9 is a test tool in which insertion holes for thermocouples having different height positions are provided on the upper side wall of the nail of the safety test apparatus of FIG. 8. FIG. 9 is a test device in which a thermocouple insertion opening having the same height is provided on the upper side wall of the nail of the safety test apparatus of FIG. 8. 4 is a test tool in which an insertion port for a thermocouple obliquely downward is provided on the upper side wall of the nail of the safety test apparatus of FIG. 3.

The present invention is a nail-like test tool used for a nail penetration test in which a nail and a temperature sensor are integrated, and can easily measure a short-circuit occurrence temperature of a battery under test, which has been difficult in the past.

At the same time, an electrolyte solution can be collected from the inside of the battery, and a mechanism that can provide a sample suitable for analysis is provided.
Hereinafter, specific examples will be described in detail.
In the following, a thermocouple is used as the temperature sensor, but it goes without saying that the same result is obtained even if another temperature sensor (a resistance temperature detector or a thermistor) is used.

Example 1
An outline of a nail penetration test device (nail) 1 in the safety test apparatus according to the present invention is shown below according to FIG.
The outer frame 3 is made of a metal having a sufficiently high hardness, for example, tool steel, so as to prevent deformation at the time of piercing and can be used repeatedly. The shape was a pierced portion outer diameter φ3.0 mm, the apex angle of the tip cone portion was 30 °, and the diameter of the sheath thermocouple insertion hole (through hole) 5 was φ0.6 mm. The sheath thermocouple insertion hole 5 is drilled from the nail root 5 at the upper end of the nail 1 and reaches the position near the tip of the nail 7 in the axially downward direction.

The sheath thermocouple 4 used was a sheath material of SUS316, a sheath outer diameter of φ0.5 mm, and a thermocouple wire of K type.
Although not depicted in FIG. 1, the output line of the sheath thermocouple 4 is connected to a recording / displaying instrument at the rear end of the sheath thermocouple 4, and the measured temperature of the short circuit inside the battery under test is measured. The recording mechanism was adopted.

As shown in FIG. 2, a transparent chamber 13 (protective box) 13 was placed on the desk 12, and the test container 8 was disposed therein. A fully charged power storage device 11 (Panasonic lithium-ion battery CGR18650C) is fixed to a fixed base 9 placed in a test container 8 where liquid does not flow out. After filling the battery 11 and completely immersing the battery 11, the nail penetration test tool having an outer diameter of 3 mm was punctured (pierced) to a depth of 12 mm at the center of the battery at a speed of 2 mm / second, and placed inside the nail. A temperature change was observed with a thermocouple 4. In addition, a thermocouple 20 that measures the surface temperature of the electricity storage device (battery) 11 and a thermocouple 21 that measures the temperature of the inert liquid 10 in the test container 8 are disposed as other thermocouples. The nail root 6 of the nail 1 is connected to the pressure head 14 and is moved up and down by the pressure head 14.

It was found that since there was no ignition or chemical change associated with the oxidation reaction, there was no rapid temperature rise, and there was no deformation or destruction of the battery. In addition, since the spraying and scattering of the electrolyte was suppressed, it could be used for structural analysis after the test.

It was confirmed that accurate measurement of the inside of the battery can be repeatedly performed with the nail penetration test device 1.
When the nail penetration test device 1 is used once, an oxide film (rust) or dirt adheres to the surface, increasing the contact resistance between the surface of the nail penetration test device 1 and the electrode inside the battery. Since the sharpness is slightly smooth, it was used only once in the case of a test measuring the occurrence of a strict internal short circuit.

Example 2
Using the same sample and test system as in Example 1 (see FIG. 2), only the nail penetration test device (nail) 1-1, as shown in FIG. The test was performed by changing to the one having a through hole 15 communicating with the outside of 1-1.

Since there is almost no compatibility between the electrolyte and inert liquid 10 (here, Fluorinert FC-40 is used as in Example 1), there is no need for troublesome separation / extraction operations, that is, electrolysis can be easily performed. The liquid could be isolated and the analysis could be arranged.

Note that the type of analyzer used is optimal depending on the material used in the electrolytic solution, and the type thereof is not limited, but examples include gas chromatography, liquid chromatography, IR spectroscopy, and the like.

Specifically, from the moment the nail 1-1 is stabbed, the inert liquid 10 starts to penetrate into the battery 11, and the electrolyte solution is present in a small amount around the through hole 15 opened at the tip of the nail 1-1. However, it is bounced by the inert liquid 10 (extruded, peeled off from the separator and the active material), floats up, and in combination with the fact that the inert liquid 10 has a larger specific gravity, it enters below and floats the electrolyte. Was able to collect 0.3 ml through the hole 15 in the nail 1-1. At the same time, the heat generation behavior of the battery could be measured with the thermocouple 4 arranged inside the nail penetration test device 1.

Example 3
Using the same test system (see FIG. 2) and method as in Example 2, the 50Ah-class lithium ion battery 11 was tested, and the head (nail root) 6-2 of the through hole 5-2 was used as a suction device. A bimol pump (medo industry sales (not shown)), which is a liquid transporting pump with excellent ability to control a small amount of suction, was attached, and when suction was forced, about 8 milliliters of electrolyte was collected. (The connection method and piping of the suction machine are not shown)

In addition, although about 8 ml was able to be collected this time, depending on the battery, it may not be collected because it does not always contain an electrolyte solution that can be collected by suction. In addition, when the purpose is only to collect the electrolytic solution, it is more preferable not to install a temperature sensor in order to make it easier to suck the electrolytic solution into the nail 1-2 as shown in FIG. Speed is increased.

Furthermore, a plurality of vertical holes 5-3, 5-3 ′, that is, a hole 5-3 ′ into which the thermocouple 4 is inserted and a sampling hole 5-3 are prepared for each (see FIG. 5), and when used, the temperature Can also be measured, and the effect of increasing the sampling speed is also brought about.

Example 4
Using the same sample and test system as in Example 1 (see FIG. 2), only the nail penetration test device (nail) 1-4 has two vertical holes 5-4, 5 and 5 having different depths as shown in FIG. -4 ′, depending on the depth of the nail 1-4, the tip of the nail 1-4 near the tip 7-4, 7-4 ′ was changed to the one where the thermocouple 4, 4 ′ was arranged, A difference in the depth direction of the heat generation behavior inside the battery 11 was observed.

For temperature measurement only, like the nail 1-5 shown in FIG. 7, two thermocouples 4 and 4 'are arranged at different insertion depths in one vertical hole 5-5. The same purpose is achieved.

Example 5
Using the same sample and test system as in Example 1 (see FIG. 2), only the nail penetration test device (nail) 1-6 has two vertical holes 5-6, 5 having different depths as shown in FIG. -6 ', and through holes 18, 18' reaching the outside of the nail 1-6 are opened in the vicinity of the tip of the nail 7-6, 7-6 'of each vertical hole 5-6, 5-6' Tests were made with changes.

The electrolyte solution in the battery 11 could be sampled 0.1 ml each through the holes 18 and 18 'opened in the nail 1-6. In addition, the heat generation behavior distribution of the battery 11 could be measured with the thermocouples 4 and 4 ′ disposed inside the nail penetration test device (nail) 1-6.

Although described in Example 3, when the purpose is only to collect the electrolyte, the temperature is set in the vertical holes 5-7 and 5-7 ′ in the nail 1-7 as shown in FIG. As described above, it is more preferable not to install a sensor (thermocouple) than the case of sucking an electrolyte, and the collection speed is also increased.

Comparative Example 1
In the same sample and test system shown in FIG. 10, the test is performed without immersing in the inert liquid 10 (see FIG. 2) in the test container 8 in the strong explosion-proof chamber structure 13 ′ for ensuring safety. The same nail penetration test conditions (temperature, battery capacity, charging conditions, nail thickness, material, needle penetration speed) as in Example 1 were conducted. Both thermocouples 4 and 20) suddenly moved up and down and ignited and ruptured almost simultaneously. As a result, the true temperature at the ignition point could not be continuously measured.

Comparative Example 2
Similar to Comparative Example 1 (see FIG. 10), the same nail penetration test except that the test battery 11 is placed in a chamber in a tough explosion-proof chamber structure 13 ′ and filled with argon gas. When the nail penetration test was carried out under the conditions (temperature, battery capacity, charging conditions, nail thickness, material, needle penetration speed), both the battery surface and the temperature inside the nail moved up and down, but ignition occurred due to the oxidation reaction. As a result, no rapid temperature rise was observed and no battery deformation or destruction occurred.

Example 6
Again, using the same sample and test system as in Example 1 described above (see FIG. 2), with regard to the nail penetration test device (nail) 1-8, as shown in FIG. The test was conducted by filling a high fluidity material 20 having high thermal conductivity between the thermocouple 4 and the inner wall of the vertical hole 5-8 in the vicinity of the tip 7-8 of the vertical hole 5-8 to be arranged. Here, the silver paste 20 was used as the high fluidity material 20.

When a fluid material 20 having high thermal conductivity such as silver paste is filled in the vicinity 7-8 of the vertical hole 5-8, even if the thermocouple 4 is in poor contact with the bottom surface of the vertical hole 5-8, the contact is made. It was found that the thermal response (sensitivity) of the same level as that obtained was obtained.

Moreover, although not shown in FIG. 11, the through-hole 15 which connects the nail point vicinity 7-1 of the vertical hole 5-8 and the exterior of the nail 1-1 similarly to Examples 1-6 may be opened, The test was also conducted by changing to a through hole. As shown in FIG. 2, 0.3 ml of the electrolyte in the battery 11 could be collected through the holes (see reference numerals 18 and 18 ′ in FIG. 3) in the nails 1-8. In addition, the heat generation behavior distribution of the battery 11 could be measured with the thermocouples 4 and 4 ′ disposed inside the nail penetration test device (nail) 1-8.

Example 7
Using the same sample and test system as in Example 6 above (see FIG. 2), with respect to the nail penetration test device (nail) 1-9, as shown in FIG. An insertion port 21 for inserting the pair 4 is provided on the side wall of the nail 1-9. Specifically, an insertion port 21 is provided in the upper side wall of the thermocouple 4 so as to penetrate from the outside to the vertical hole 5-9 in a direction orthogonal to the vertical hole 5-9. Even in this case, the silver paste 20 (see FIG. 11) may be filled in the vicinity of the apex 7-9 of the vertical hole 5-9.

In addition, although not shown in FIG. 12, the test was performed by changing to the one in which the through hole 15 communicating the nail point vicinity 7-9 of the vertical hole 5-9 and the outside of the nail 1-9 was opened. As shown in FIG. 2, 0.3 ml of the electrolyte solution in the battery 11 could be collected through the holes (see reference numerals 18 and 18 'in FIG. 3) in the nails 1-9. In addition, the heat generation behavior distribution of the battery 11 could be measured with the thermocouples 4 and 4 ′ arranged inside the nail penetration test device (nail) 1-9.

Example 8
Using the same sample and test system as in Example 4 (see FIG. 2), as shown in FIG. 13 for the nail penetration test device (nail) 1-4, the nail 1-10 has vertical holes 5-10, 5- Two 10 'are provided. The depths of the vertical holes 5-10 and 5-10 ′ are different depth positions, and the thermocouples 4 and 4 ′ are disposed in the vertical holes 5-10 and 5-10 ′. The nail 1-10 has a feature in the positions of the insertion ports 21 and 21 '. FIG. 14 shows a case where insertion ports 21 and 21 ′ are provided at the same height position on the side wall of the nail 1-4 shown in FIG. In this case, since the depths of the vertical holes 5-11 and 5-11 ′ are not known, there is a possibility of erroneous insertion (too much pressing or insufficient pressing) when inserting the thermocouples 4 and 4 ′. In order to prevent erroneous insertion, it takes time to insert thermocouples 4 and 4 ′, which is not suitable for mass production. On the other hand, in the nail 1-10 of FIG. 13, the heights of the insertion ports 21 and 21 ′ are made different from each other so that the insertion ports 21 and 21 ′ can reach the positions of the vertical holes 7-10 and 7-10 ′. The height is substantially the same. Therefore, the positions of the insertion holes of the thermocouples 4 and 4 ′ can be known according to the depth of the vertical holes 5-10 and 5-10 ′, and the vertical hole position (individual information) can be determined from the opening position, thereby preventing erroneous insertion. .

Although not shown in FIG. 13, through holes 15 are formed to communicate the vertical holes 5-10 and 5-10 ′ with the vicinity of the tip of the nail 7-10 and 7-10 ′ and the outside of the nail 1-10. The test was conducted after changing to a different one. As shown in FIG. 2, 0.1 ml of the electrolyte solution in the battery 11 could be collected through holes (see reference numerals 18 and 18 ′ in FIG. 3) formed in the nail 1-10. In addition, the heat generation behavior distribution of the battery 11 could be measured with the thermocouples 4 and 4 ′ arranged inside the nail penetration test device (nail) 1-10.

Example 9
As an improved example of the sixth embodiment, with respect to the nail 1-12, as shown in FIG. 15, the insertion port 21 of the nail 1-12 is formed obliquely downward. With this shape, it was found that there was little damage when inserted into the vertical hole 5-12 of the thermocouple 4 from the insertion port 21, insertion was possible at a loose angle, and it was found that insertion was possible in a short time.

Although not shown in FIG. 12, the test was performed by changing to the one in which the through hole 15 communicating the nail point vicinity 7-12 of the vertical hole 5-12 and the outside of the nail 1-12 was opened. As shown in FIG. 2, 0.3 ml of the electrolyte solution in the battery 11 could be collected through holes (see reference numerals 18 and 18 ′ in FIG. 3) formed in the nail 1-12. In addition, the heat generation behavior distribution of the battery 11 could be measured with the thermocouples 4 and 4 ′ disposed inside the nail penetration test device (nail) 1-12.

The safety evaluation test method and the safety evaluation test apparatus according to the present invention have been described above by way of example. However, it is easily understood by those skilled in the art that the present invention includes various modifications without departing from the scope of the claims. I understand.

1 Nail (nail penetration test device)
4 Thermocouple 5 Vertical hole 6 Nail root 7 Tip 8 Test vessel 9 Fixing base 10 Inert liquid 15-19 Through hole 21 Insertion port

Claims (17)

Prepare a test container to store the inert liquid,
Immerse it completely in an inert liquid by placing the electricity storage device in a test container,
A safety evaluation test method for performing a predetermined safety evaluation test for an electricity storage device. The safety evaluation test method according to claim 1, wherein the predetermined safety evaluation test is any one of a nail penetration test, an overcharge test, and a heating test. The predetermined safety evaluation test for the electricity storage device is a nail penetration test,
A safety evaluation test method for puncturing with a nail having a sharp tip with respect to an electricity storage device that is completely immersed in an inert liquid stored in the test container,
The nail forms a vertical hole opened from the nail root to the vicinity of the tip of the nail, and at least a temperature sensor is disposed in the vertical hole,
In addition, a through hole that communicates the outside of the nail and the vertical hole is formed near the apex of the vertical hole, and at least a part of the contents of the electricity storage device can be collected through the through hole at the time of puncturing The safety test method according to claim 1. The predetermined safety evaluation test for the electricity storage device is a nail penetration test in which an electricity storage device completely immersed in an inert liquid stored in a test container is punctured with a nail with a sharp tip,
The nail is
A vertical hole opened from the nail root to the vicinity of the tip of the nail is provided, and at least a temperature sensor is disposed in the vertical hole,
In addition, a safety testing device for an electricity storage device, wherein a through-hole that communicates the outside of the nail and the vertical hole is formed near the tip of the vertical hole. The predetermined safety evaluation test for the electricity storage device is a nail penetration test in which an electricity storage device completely immersed in an inert liquid stored in a test container is punctured with a nail with a sharp tip,
The nail is
A vertical hole is formed from the nail root to the vicinity of the tip of the nail,
In addition, a safety testing device for an electricity storage device, wherein a through-hole that communicates the outside of the nail and the vertical hole is formed near the tip of the vertical hole. When the predetermined safety evaluation test is an overcharge test, a current can be supplied from the overcharge test power supply installed outside the test container to the positive and negative terminals of the electricity storage device installed inside the test container. 6. The safety evaluation test apparatus according to claim 4, wherein a current supply terminal is provided in the test container. When the predetermined safety evaluation test is a heating test, a current is supplied from a heating test power supply installed outside the test container to a heater placed in the vicinity of the electricity storage device installed inside the test container. 6. The safety evaluation test apparatus according to claim 4, wherein a current supply terminal that can be used is provided in the test container. The safety test method according to claim 1, wherein the inert liquid is Florinart, Galden, or silicone oil. The predetermined safety evaluation test for the electricity storage device is a nail penetration test in which an electricity storage device completely immersed in an inert liquid stored in a test container is punctured with a nail with a sharp tip,
The nail is
Two or more vertical holes opened from the nail root to the vicinity of the tip of the nail are provided, and the depths of the vertical holes are different from each other, and at least one temperature sensor is disposed in each vertical hole,
A safety testing device for an electricity storage device, wherein a through-hole that communicates the outside of the nail and the vertical hole is formed in the vicinity of the tip of each vertical hole. The predetermined safety evaluation test for the electricity storage device is a nail penetration test in which an electricity storage device completely immersed in an inert liquid stored in a test container is punctured with a nail with a sharp tip,
The nail is
A vertical hole opened from the nail root to the vicinity of the tip of the nail is provided, and at least two temperature sensors are disposed in the vertical hole,
In addition, a safety testing device for an electricity storage device, wherein a through-hole that communicates the outside of the nail and the vertical hole is formed near the tip of the vertical hole. The predetermined safety evaluation test for the electricity storage device is a nail penetration test in which an electricity storage device completely immersed in an inert liquid stored in a test container is punctured with a nail with a sharp tip,
The nail is
Two or more vertical holes opened from the nail root to the vicinity of the tip of the nail are provided, and at least one temperature sensor is disposed in each of the vertical holes,
In addition, a safety testing device for an electricity storage device, wherein each through-hole communicating the outside of the nail and the vertical hole is formed in the vicinity of the tip of each vertical hole. The safety evaluation test apparatus according to claim 5, wherein the temperature sensor is a thermocouple, a thermistor, or a resistance temperature detector. The predetermined safety evaluation test for the electricity storage device is a nail penetration test in which the electricity storage device is punctured with a nail having a sharp tip, and the nail is
A vertical hole opened from the nail root to the vicinity of the tip of the nail is provided, and a temperature sensor is disposed in the vertical hole,
An electrical storage device safety testing apparatus characterized by filling a fluid material having high thermal conductivity in the vicinity of the tip of the vertical hole and between the temperature sensor and the inner wall of the vertical hole. The predetermined safety evaluation test for the electricity storage device is a nail penetration test in which the electricity storage device is punctured with a nail having a sharp tip, and the nail is
A vertical hole opened from the nail root to the vicinity of the tip of the nail is formed, and at least when the temperature sensor is disposed in the vertical hole, an insertion port for inserting the temperature sensor into the vertical hole is provided on the side wall of the nail. An electrical storage device safety test apparatus characterized by the above. The predetermined safety evaluation test for the electricity storage device is a nail penetration test in which the electricity storage device is punctured with a nail having a sharp tip, and the nail is
Two or more vertical holes drilled from the nail root to the vicinity of the tip of the nail are provided, and the depths of the vertical holes are different from each other. When arranging at least one temperature sensor in each vertical hole, The insertion holes for inserting the temperature sensors into the respective vertical holes are opened in the side walls of the nail, and the positions of the insertion holes from the nail roots are opened in accordance with the depths of the respective vertical holes. An electrical storage device safety test apparatus characterized by comprising: The predetermined safety evaluation test for the electricity storage device is a nail penetration test in which the electricity storage device is punctured with a nail having a sharp tip, and the nail is
When a vertical hole is formed from the nail root to the vicinity of the tip of the nail, and at least the temperature sensor is disposed in the vertical hole, an insertion port for inserting the temperature sensor into the vertical hole has a side wall of the nail, and the insertion An electrical storage device safety testing apparatus, characterized in that the mouth opens obliquely downward from the nail root toward the tip of the nail. The safety of the electricity storage device according to any one of claims 13 to 16, wherein a through-hole that communicates the outside of the nail and the vertical hole is formed in the vicinity of the tip of each vertical hole. Test equipment.