A battery safety test system

Abstract

The embodiment of the present invention discloses a battery safety test system, which includes: a battery bracket for supporting a battery clamp; a battery sample as a test object, fixed by the battery clamp; an impactor ejection device, placed at a first set distance from the battery sample, for launching an impactor in a direction perpendicular to the battery plate; an impactor velocimeter for monitoring the speed of the impactor during the launch process after it is ejected from the impactor ejection port; a first camera, placed at a second set distance from the battery sample, for recording the phenomenon that occurs in the battery sample after the impactor penetrates the battery sample, and the phenomenon is used to evaluate the safety level of the battery sample when it is hit by the impactor. By adopting the above technical solution, it is possible to truly simulate the test condition in which the impactor first penetrates the protective steel plate and then is embedded in the battery, and the test results generated have good distinguishability and repeatability.

Description

Technical Field

[0001] The invention relates to the technical field of batteries, and in particular to a battery safety test system. Background Art

[0002] Lithium-ion batteries have the advantages of high energy density and large discharge rate, and are widely used in electric equipment, mobile power stations, portable power sources and other fields. As the energy density becomes higher and the capacity becomes larger, the safety of lithium-ion batteries is becoming more and more concerned. Especially when hit by high-speed objects such as impactors or fragments, it can cause fire, combustion and even explosion. Therefore, it is particularly important to construct a safety evaluation method for lithium-ion batteries when they are shot, so as to guide the safety design of batteries and select safe batteries suitable for battlefields.

[0003] At present, the current national standards mainly include four test methods for testing battery safety through physical damage: drop, vibration, extrusion or needle puncture. These four test methods play an important role in their respective application fields, but they cannot effectively simulate the test conditions of high-speed impact or destruction of batteries when they are shot, and thus cannot fully and accurately evaluate the safety of batteries when they are shot.

[0004] In addition, the test method for batteries subjected to impact only briefly stipulates the type of impactor ejection device, impactor distance, and test object. For example, in the current "General Specifications for Lithium-ion Battery Packs", the method steps and evaluation indicators for battery safety testing are: placing a fully charged battery pack sample at a distance of 50 meters, and the test result is that after the battery is hit, it should not catch fire or explode, but leakage and exhaust are allowed; in the "Safety Requirements for Lithium Batteries", the method steps and evaluation indicators for battery safety testing are: placing the battery at a distance greater than 25 meters, and after the battery is hit by an impactor, the test result is that it does not explode or burn.

[0005] It can be seen from this that the above test method for inspecting battery safety cannot truly simulate the situation where the impactor first penetrates the steel plate used to protect the battery and then embeds into the battery, that is, it cannot effectively simulate the test condition where the battery is hit or destroyed at high speed when hit by an impactor. When the test is conducted according to the above test method, the test results do not have good discrimination and repeatability, and thus cannot fully and accurately evaluate the safety of the battery when hit by an impactor. Summary of the invention

[0006] The embodiment of the present invention discloses a battery safety test system, which can truly simulate a test condition in which an impactor first penetrates a protective steel plate and then is embedded in a battery, and the test results generated have good distinguishability and repeatability.

[0007] The embodiment of the present invention discloses a battery safety test system, which includes:

[0008] The shot unit, the shooting unit and the monitoring unit; wherein the shot unit includes: a battery bracket, a battery fixture and a battery sample; the shooting unit includes: an impactor ejection device, a bracket supporting the impactor ejection device and an impactor; the monitoring unit includes: a first camera and an impactor speed meter; wherein,

[0009] The battery bracket is used to support the battery clamp;

[0010] The battery sample is used as a test object and is fixed by the battery fixture;

[0011] The impactor ejection device is placed at a first set distance from the battery sample and is used to eject the impactor in a direction perpendicular to the battery plate; the impactor velocity meter is used to monitor the velocity of the impactor during the ejection process after ejecting from the impactor ejection port;

[0012] The first camera is placed at a second set distance from the battery sample, and is used to record phenomena occurring in the battery sample after the impactor penetrates the battery sample, and the phenomena are used to evaluate the safety level of the battery sample when it is hit by the impactor;

[0013] Among them, the phenomena that occur in the battery sample after being hit by the impactor include one or more of the following:

[0014] Whether there are holes on the battery surface caused by impact objects, changes in the internal structure, gas or liquid leakage from the battery, toxicity of the gas or liquid, open flame, and explosion after open flame.

[0015] Optionally, the test system further includes:

[0016] A second camera is placed at a third set distance from the battery sample and is used to record changes in the battery from the start of the test to the end of the test;

[0017] The change phenomena include one or more of the following: being hit by an impact object, battery falling, liquid leakage, smoking, burning, explosion, color of leaked liquid, changes in the liquid and the bracket after contact, color of smoke, diffusion range, color of flame, shape of flame, diameter of fireball, length of flame and the number of fragments after explosion.

[0018] Optionally, the test system further includes:

[0019] A temperature sensor, including six temperature probes, for detecting temperature changes of the battery sample at different times after being hit by an impactor;

[0020] Among them, the measuring point of the first probe is arranged on the incident surface of the impactor, 3 cm away from the geometric center of the battery; the measuring point of the second probe is arranged on the exit surface of the impactor, 3 cm away from the geometric center of the battery; the measuring point of the third probe is arranged at the battery leakage valve; the measuring point of the fourth probe is arranged 12 cm directly above the battery; the measuring point of the fifth probe is arranged 18 cm directly above the battery; the measuring point of the sixth probe is arranged 30° to the left of the front of the battery and 14 cm away from the battery.

[0021] Optionally, the test system further includes:

[0022] The infrared imager is arranged 3 meters away from the battery sample, and the angle formed by the line connecting the infrared imager and the battery sample and the line connecting the impactor exit and the battery sample is 45°.

[0023] Optionally, the number of the impactor velocimeters is two, namely a first impactor velocimeter and a second impactor velocimeter arranged front and back along the impactor launching direction;

[0024] The distance between the first impactor velocity meter and the second impactor velocity meter is 1 meter;

[0025] The distance between the second impactor velocity meter and the impactor exit port is 1.5 meters;

[0026] The distance between the impactor exit port and the battery incident surface is 8 meters.

[0027] Optionally, the test system further includes:

[0028] The smoke tester is arranged at the fourth set distance from the battery sample. The angle formed by the line connecting the two points of the smoke tester and the battery sample and the line connecting the two points of the impactor and the battery sample is 20°. The smoke tester is used to detect whether the battery sample produces smoke when it is hit by the impactor, so as to determine the safety level of the battery sample when it is hit by the impactor.

[0029] Optionally, the smoke tester is further used to test smoke concentration, opacity, average particle diameter and particle composition after the battery sample generates smoke, so as to determine the degree of damage to the battery sample.

[0030] Optionally, the battery clamp comprises: a first baffle, a frame, a second baffle and an alligator clip, wherein:

[0031] The first baffle plate and the second baffle plate are placed opposite to each other, and there is a gap between the first baffle plate and the second baffle plate for accommodating the battery sample;

[0032] There are four alligator clips, which are used to clamp and fix the second baffle and the four top corners of the frame respectively;

[0033] The first baffle is embedded in the outer surface of the frame and is used to encapsulate the battery sample inside the battery fixture.

[0034] Optionally, the rear baffle is made of tungsten steel alloy.

[0035] Optionally, an angle formed by a line connecting two points of the first camera and the battery and a line connecting two points of the impactor exit and the battery is 70°.

[0036] The technical solution provided by the embodiment of the present invention provides a battery safety test system, which includes a shot unit, a shooting unit and a monitoring unit; wherein the shot unit includes: a battery holder, a battery fixture and a battery sample; the shooting unit includes: an impactor ejection device, a holder supporting the impactor ejection device and an impactor; and the monitoring unit includes a first camera and an impactor velocity meter. Among them, the battery holder is used to support the battery fixture; the battery sample is used as a test object and is fixed by the battery fixture; the impactor ejection device is placed at a first set distance from the battery sample and is used to launch the impactor in a direction perpendicular to the battery plate; the impactor velocity meter is used to monitor the speed of the impactor during the launch process; the first camera is placed at a second set distance from the battery sample and is used to record the phenomenon of the battery sample after the impactor penetrates the battery sample. The system can realistically simulate the situation where the impactor first penetrates the steel plate used to protect the battery and then is embedded in the battery. By recording the phenomenon of the battery sample after the impactor penetrates the battery sample, the phenomenon can be used to evaluate the safety level of the battery sample when it is shot by the impactor, so that the test results generated have good repeatability and distinguishability.

[0037] The invention points of the present invention include:

[0038] 1. Construct a battery safety test system, which includes a shot unit, a shooting unit and a monitoring unit, wherein the shot unit includes: a battery holder, a battery clamp and a battery sample; the shooting unit includes: an impactor ejecting device, a holder supporting the impactor ejecting device and an impactor; the monitoring unit includes: a first camera and an impactor velocimeter; wherein the battery holder is used to support the battery clamp; the battery sample is used as a test object and is fixed by the battery clamp; the impactor ejecting device is placed at a first set distance from the battery sample and is used to launch an impactor in a direction perpendicular to the battery plate; the impactor velocimeter is used to monitor the speed of the impactor during the launching process; the first camera is placed at a second set distance from the battery sample and is used to record the phenomenon occurring in the battery sample after the impactor penetrates the battery sample, and the phenomenon is used to evaluate the safety level of the battery sample when it is shot by the impactor. The above-mentioned test system can realistically simulate the situation where an impactor first penetrates the steel plate used to protect the battery and then embeds into the battery, and effectively simulates the test condition where the battery is hit or destroyed at high speed when hit by an impactor. According to the test results, the safety of the battery when hit by an impactor can be accurately evaluated, which is one of the inventive points of the present invention.

[0039] 2. An embodiment of the present invention provides a battery clamp, which is mainly composed of a front baffle, a front frame, a rear baffle and an alligator clip. There is a gap between the front baffle and the rear baffle for accommodating battery samples; the alligator clip is used to clamp and fix the front baffle, the front frame, the battery sample and the rear baffle; the front baffle is embedded in the front frame to encapsulate the battery sample inside the battery clamp. By adopting this clamp, it can be ensured that the battery will not fall when it is shot. At the same time, in order to make the clamp have good versatility for batteries of different shapes, it is helpful to realistically simulate the situation where the impactor first penetrates the steel plate used to protect the battery and then is embedded in the battery. This is one of the inventive points of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0041] Figure 1 A schematic diagram of the overall layout of a site provided by an embodiment of the present invention;

[0042] Figure 2 A schematic diagram of a battery safety test system provided by an embodiment of the present invention;

[0043] Figure 3 A structural design diagram of a battery clamp provided by an embodiment of the present invention;

[0044] Figure 4 A flowchart of a battery safety test method provided by an embodiment of the present invention;

[0045] Figure 5 A temperature measurement point layout diagram of a temperature sensor provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] It should be noted that the terms "including" and "having" and any variations thereof in the embodiments of the present invention and the accompanying drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device including a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products or devices.

[0048] The technical solution provided by the embodiment of the present invention mainly evaluates the safety of the battery by analyzing the phenomena exhibited by the battery after being hit by an impact object. Since the battery may have open fire, explosion and other phenomena when being hit by an impact object, the technical solution provided by the embodiment of the present invention requires the preparation of a safe and reliable test site in advance.

[0049] See also Figure 1 . Figure 1 This is a schematic diagram of the overall layout of the site provided by the embodiment of the present invention. Figure 1 As shown, the site is divided into a safe area, an unsafe area, a dangerous area and a test area. People in the safe area can observe and take photos, or hide or operate the monitoring instrument trigger switch, etc. The unsafe area is the location where the impactor is launched. No other people are allowed to move around in the area except the shooter. The dangerous area refers to the area around the battery. After being hit by the impactor, the battery's own fragments and the impactor's fragments will splash around. No equipment can be placed in this area, and no people can stay. The test area is the area where the lithium-ion battery is shot by the impactor. It is mainly used to place the test monitoring unit (infrared imager, temperature sensor, high-speed camera, digital camera), the shot unit (battery bracket, battery fixture, battery sample) and the shooting unit (impactor, impactor shooting device and the bracket supporting the impactor shooting device).

[0050] In addition, a safety fireproof and bulletproof wall is installed on the periphery of the site to prevent impact objects from flying out of the site and increasing safety hazards. A safety hole is set behind the shot battery. One is to prevent the impact object from flying into the hole when the impact object ejection device is calibrated to increase environmental safety; the other is to place the tested batteries in the hole to prevent secondary combustion or explosion. A water reservoir is set in the danger zone, which is mainly used to cool the iron battery rack to improve the efficiency of the test. Fire-fighting equipment is set up in the safe zone, mainly to extinguish the fire source of the battery and its explosion fragments. After the site layout is completed, the establishment of a test system for battery safety can be completed. This test system can truly simulate the process of lithium-ion batteries being hit by impact objects, especially it can simulate the test conditions where the impact object first penetrates the protective steel plate and then is embedded in the battery. For details, please refer to Figure 2 .

[0051] Figure 2 A schematic diagram of a battery safety test system provided by an embodiment of the present invention. Figure 2 As shown, the test system provided in this embodiment specifically includes: a shot unit, a shooting unit and a monitoring unit; wherein the shot unit includes: a battery bracket 1, a battery clamp (not shown in the figure) and a battery sample 2; the shooting unit includes: an impactor ejection device 3, a bracket 4 supporting the impactor ejection device and an impactor (not shown in the figure); the monitoring unit includes a first camera 5 and an impactor speed meter 6; wherein,

[0052] A battery bracket 1, used for supporting the battery fixture;

[0053] Battery sample 2 is used as the test object and is fixed by a battery fixture;

[0054] The impactor ejection device 3 is placed at a first set distance from the battery sample 2 and is used to eject the impactor in a direction perpendicular to the battery plate; the impactor velocity meter 6 is used to monitor the velocity of the impactor during the ejection process after the impactor is ejected from the ejection port of the impactor ejection device 3;

[0055] The first camera 5 is placed at a second set distance from the battery sample 2 and is used to record phenomena occurring in the battery sample 2 after the impactor penetrates the battery sample 2. The phenomena are used to evaluate the safety level of the battery sample 2 when it is hit by the impactor.

[0056] In this embodiment, the positions of each unit are preferably: the distance between the impactor outlet of the impactor ejection device and the incident surface of the battery is 8 meters; the distance between the impactor outlet and the impactor velocity meter is 1.5 meters; the distance between the two rangefinders is 1 meter; the distance between the first camera and the battery is 2.5 meters, and the angle formed by the line connecting the first camera 5 and the battery 2 and the line connecting the impactor outlet and the battery is about 70°. It should be noted that the placement position of each unit in the test system provided in this embodiment can also be arbitrarily set according to empirical values, and this embodiment does not make specific restrictions on this. The above test system can truly simulate the situation where the impactor first penetrates the steel plate used to protect the battery and then is embedded in the battery, and effectively simulates the test condition where the battery is hit or destroyed at high speed when hit by an impactor. According to the test results, the safety of the battery when hit by an impactor can be accurately evaluated, which is one of the inventive points of the present invention.

[0057] In this embodiment, the first camera is a high-speed camera. Compared with ordinary cameras, high-speed cameras have faster continuous shooting speeds, which can reach dozens or even thousands of frames per second, and the resolution of each frame is higher than that of video cameras. In this embodiment, the basic condition for evaluating the battery safety level is that the impactor penetrates the battery or is embedded in the battery, and the main function of the high-speed camera is to prove that the impactor has indeed penetrated the battery or is embedded in the battery. In addition, during the test, some batteries may produce micro flames. It is not enough to view this phenomenon only through ordinary cameras. Therefore, it is necessary to use high-speed cameras to determine whether the micro flames are generated by the battery or the impactor.

[0058] In this embodiment, the battery samples, i.e., the objects of the shooting test, include single cells and module batteries. In terms of storage capacity, the storage capacity of the single cell is specified to be 20Ah to 100Ah, the total voltage of the module battery is not less than 5 times the voltage of the single cell, and the rated capacity is not less than 100Ah, which is convenient for the horizontal evaluation of the safety performance of the lithium-ion battery. In terms of the state of charge, the power of the single cell and the module battery is 100%, 50%, and 0%, which is convenient for the vertical evaluation of the safety performance of the same battery under different power conditions.

[0059] In order to ensure that the battery does not fall when it is shot, and also to make the clamp have good versatility for batteries of different shapes, this embodiment provides a battery clamp, which includes: a first baffle, a frame, a second baffle and an alligator clip, wherein the first baffle and the second baffle are placed opposite to each other, and there is a gap between the first baffle and the second baffle for accommodating the battery sample; there are four alligator clips, which are respectively used to clamp and fix the second baffle and the four top corners of the frame; the first baffle is embedded in the outer surface of the frame, and is used to encapsulate the battery sample inside the battery clamp. For details, please refer to Figure 3 ,.

[0060] Figure 3 A structural design diagram of a battery clamp provided by an embodiment of the present invention, such as Figure 3 As shown, the battery clamp is mainly composed of a front baffle, i.e., a first baffle ( Figure 3 Not shown), frame ( Figure 3 The front frame in the middle), the second baffle ( Figure 3 The front baffle and the rear baffle are arranged successively along the direction of the impactor, with a gap between them for accommodating the battery sample; the alligator clip is used to clamp and fix the front baffle, the front frame, the battery sample and the rear baffle; the front baffle is embedded in the front frame to encapsulate the battery sample inside the battery fixture.

[0061] Specifically, the alligator clip is made of high temperature resistant material with a frosted surface; the rear baffle is made of tungsten steel alloy to keep the impactor inside the battery; the front frame has good bending, that is, the steel plate with the center area hollowed out is made of 45# steel with an unquenched hardness less than HRC28. The front baffle can be a 5mm thick Q235 steel plate. By adopting the above-mentioned clamp, it can be ensured that the battery will not fall when it is shot, and at the same time, in order for the clamp to have good versatility for batteries of different shapes, it is helpful to realistically simulate the situation where the impactor first penetrates the steel plate used to protect the battery and then is embedded in the battery, which is one of the inventive points of the present invention.

[0062] After the site and test system are arranged, the battery firing test can be started. This embodiment provides a test method that is highly operable and convenient for evaluating the safety of different lithium-ion batteries after firing, and the test results produced have good repeatability and distinguishability. Figure 4 .

[0063] Figure 4 A flowchart of a battery safety test method provided by an embodiment of the present invention is as follows: Figure 4 As shown, before the test actually starts, the battery can be charged according to the test regulations, and the impactor and impactor ejection device can be selected. After the selection is completed, the weather conditions need to be judged. If there is rain, snow or strong wind, the test ends. When the weather conditions are good, the test can continue.

[0064] Before the test, the integrity of each instrument must be checked, and the verified intact instruments must be placed in place and anti-collision glass must be installed. Then install the battery, baffle and text sensor probe on the battery fixture. After the installation is completed, if it is determined that the battery has abnormal phenomena such as natural or explosive phenomena, the battery sample must be replaced, that is, the battery installation operation must be performed again. If no abnormal phenomena occur after the safety is completed, the switches of monitoring instruments such as temperature sensor receivers, high-speed cameras, video cameras, infrared thermal imagers, etc. are turned on for monitoring. The shooting personnel start the shooting operation after hiding. The specific shooting process can be: aiming at the geometric center of the battery for shooting (so that the impactor penetrates from a direction perpendicular to the battery plate, and the impactor shooting speed is not less than 750m / s). If the battery is not hit, the shooting operation is repeated; if the battery is hit, the test phenomenon is recorded, and after the data in each monitoring instrument no longer changes, the data in the monitoring instrument is exported, and the instrument switch is turned off. The test conclusion is obtained by analyzing the test phenomenon and test data, such as the battery bulging size, the incident and exit hole diameters, etc.

[0065] In this embodiment, in order to facilitate the evaluation of the safety of the battery, the test phenomena that may occur after the battery is penetrated by an impact object can be used to divide the safety level from light to heavy into six levels: level 3 safety, level 2 safety, level 1 safety, level 1 danger, level 2 danger, and level 3 danger. The test phenomena corresponding to different safety levels are shown in Table 1 below. Combined with Table 1, the safety level of the lithium-ion battery can be obtained through the test phenomena.

[0066] Table 1 Comparison table of safety level and test phenomenon

[0067]

[0068] Among them, the judgment method of the test phenomenon is as follows: (1) If the battery is perforated by the impact object, it is judged by naked eye observation. (2) If the internal structure of the battery is uneven or distorted, a gamma-ray cutting tool can be used to cut the battery along the direction of the impact object to observe the damage characteristics of the internal structure of the battery; (3) For gas and liquid leakage, the weighing method before and after the test and the smoke tester method can be used; (4) Whether the gas or liquid is toxic or harmful can be judged based on the corrosiveness of the gas and liquid to the battery clamp and battery bracket; (5) For open flames and explosions, a high-speed camera is used for photo identification. In particular, for batteries containing harmful elements such as sulfur, if such batteries leak during the test, the safety level will be directly identified as level one hazard.

[0069] Based on the above embodiments, Figure 2As shown, the test system provided by the embodiment of the present invention also includes a second camera 7, which is placed at a third set distance from the battery sample, and is used to record the changes in the battery during the entire process from the start of the test to the end of the test. The second camera can be a digital camera, and the third set distance can be 2.5 meters. The digital camera mainly records the entire process of the shooting test, which may include being hit by an impactor, whether the impactor has perforations on the surface of the battery, battery falling, leakage, smoking, burning, explosion, color of the leaked liquid, changes in the liquid and the bracket after contact, color of the smoke, diffusion range, color of the flame, shape of the flame, fireball diameter, flame length, explosion power and the number of fragments after the explosion, etc.

[0070] On the basis of the above-mentioned embodiments, the test system provided by the embodiments of the present invention also includes: a temperature sensor, including six temperature probes, which are used to detect the temperature changes of the battery sample at different times after being hit by an impact object. The temperature index detected by the temperature sensor and the above-mentioned test phenomenon can be used as standards for evaluating the safety of the battery. Specifically, the detected temperature index can be used to further refine the classification of batteries within the same safety level, that is, the safety level of the battery can be roughly divided according to the test phenomenon, and then the safety level of the battery can be finely divided according to the temperature index. The temperature index and the test phenomenon are interdependent and mutually confirmed, so that the test results have good distinguishability, which is one of the inventive points of the present invention. Among them, the temperature sensor provided in this embodiment can preferably be a K-row temperature sensor. For the layout diagram of the detection points of the temperature sensor, please refer to Figure 5 .

[0071] like Figure 5 As shown, the measuring point a of the first probe of the K-type temperature sensor is arranged on the incident surface of the impactor, 3 cm away from the geometric center of the battery; the measuring point b of the second probe is arranged on the exit surface of the impactor, 3 cm away from the geometric center of the battery; the measuring point c of the third probe is arranged at the battery leakage valve; the measuring point d of the fourth probe is arranged 12 cm above the battery, because according to the test data, 12 cm is the flame core of the large battery flame jet and the outer flame of the small battery flame jet. The measuring point e of the fifth probe is arranged 18 cm above the battery, because according to the test data, 18 cm is the outer flame of the large battery flame jet; the measuring point f of the sixth probe is arranged 30° to the left of the front of the battery and 14 cm away from the battery. This is set because according to the test data, 14 cm is the outer flame of the flame jet of most battery bullet holes.

[0072] In this embodiment, the contents that can be analyzed by the K-type temperature sensor include: temperature curve trend, injection point temperature, ignition point temperature, temperature rise period, temperature stable period, temperature drop period, duration of different temperature stages, maximum temperature, minimum temperature and average temperature.

[0073] Based on the above embodiments, Figure 2 As shown, the test system provided by the embodiment of the present invention also includes: an infrared imager 8, which is arranged 3 meters away from the battery sample, with an angle of 45° formed by a line connecting two points of the battery sample and a line connecting the impactor exit and the two points of the battery sample, for measuring temperature data.

[0074] On the basis of the above embodiment, the test system provided by the embodiment of the present invention further includes: a smoke tester 9, which is arranged at the fourth set distance from the battery sample. The angle formed by the line connecting the two points of the smoke tester and the battery sample, and the angle formed by the line connecting the two points of the impactor and the battery sample is 70°. The smoke tester is used to test the smoke concentration, opacity, average particle diameter, and particle composition displayed in the smoke tester after the battery produces smoke and smoke. Specifically, the moment when the impactor enters the battery can be used as the test zero point, and the moment when the data of each indicator remains constant can be used as the test end point. The acquisition frequency of the smoke tester is 1 time / second, and the curves of the above four indicators can be drawn. By comparing the highest point, the lowest point, the curve trend, the curve rise and decrease rate, etc. of the four indicator curves of different batteries, the degree of battery damage can be obtained. It is particularly pointed out that in order to ensure the accuracy of the numerical value of the smoke tester, the test must be carried out under the conditions of no rain, snow, wind and clear weather.

[0075] On the basis of the above-mentioned embodiment, in order to increase the integrity of the parameters of the shooting test object, the embodiment of the present invention further provides a size measurement method, which mainly includes the following three aspects:

[0076] (1) Use a ruler to measure the length, width, height and other dimensions of the battery.

[0077] (2) Using an infrared rangefinder = measuring the size of the image derived from the on-site test instrument, and then calculating it according to the corresponding relationship of the scale. Specifically, the infrared rangefinder can measure the flame size and smoke diffusion range in the video image, and calculate the theoretical values ​​of parameters such as flame length and smoke diffusion range according to the scale.

[0078] (3) The indirect measurement method is used to measure the size of the bullet entry and exit holes of the battery. First, methyl red and tannic acid reagents are applied to the outer edge of the bullet hole, and then the print is printed on rice paper. After the print on the rice paper is dry, the size of the largest outer edge of the print is measured with a vernier caliper.

[0079] This embodiment is set up in this way, and more detailed indicators under the safety level can be obtained, such as smoke diffusion range and flame length, etc. These indicators can be used to rank the dangerousness of batteries of the same safety level, so as to meet the adaptability requirements of different application scenarios, which is one of the inventive points of the present invention. For example: two batteries were subjected to a shooting test. For user A, he only needs to know the safety level of the battery, so he does not need to measure subtle parameters such as flame length, and only needs to observe the phenomenon to judge the level; for user B, he wants to know which battery is safer, so he needs to compare subtle parameters such as smoke diffusion range and flame length.

[0080] On the basis of the above embodiments, in order to facilitate the analysis of the test phenomenon, the data during the test process can be recorded. Specifically, the following data can be recorded: basic parameters of the battery (battery number, battery type, battery capacity, battery power and battery manufacturer), test conditions (battery serial number, penetration baffle thickness, tungsten steel plate thickness, shooting distance, impactor type, impactor speed), meteorological conditions (atmospheric temperature, relative humidity, atmospheric pressure, wind speed, wind direction and weather conditions), test phenomena during the test, battery surface temperature, battery surface maximum temperature and average temperature, battery bullet hole size and test conclusions, etc.

[0081] The technical solution provided in this embodiment provides a battery safety test system, which includes a shot unit, a shooting unit and a monitoring unit; wherein the shot unit includes: a battery holder, a battery fixture and a battery sample; the shooting unit includes: an impactor ejection device, a bracket supporting the impactor ejection device and an impactor; and the monitoring unit includes a first camera and an impactor velocimeter. Among them, the battery holder is used to support the battery fixture; the battery sample is used as a test object and is fixed by the battery fixture; the impactor ejection device is placed at a first set distance from the battery sample and is used to launch the impactor in a direction perpendicular to the battery plate; the impactor velocimeter is used to monitor the speed of the impactor during the launch process; the first camera is placed at a second set distance from the battery sample and is used to record the phenomenon of the battery sample after the impactor penetrates the battery sample. The system can realistically simulate the situation where the impactor first penetrates the steel plate used to protect the battery and then is embedded in the battery. By recording the phenomenon of the battery sample after the impactor penetrates the battery sample, the phenomenon can be used to evaluate the safety level of the battery sample when it is shot by the impactor, so that the test results generated have good repeatability and distinguishability.

[0082] The battery safety test system disclosed in the embodiment of the present invention is introduced in detail above. The principle and implementation mode of the present invention are explained in this article by using specific examples. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation mode and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A battery safety test system, characterized in that: include: The shot unit, the shooting unit and the monitoring unit; wherein the shot unit includes: a battery bracket, a battery fixture and a battery sample; the shooting unit includes: an impactor ejection device, a bracket supporting the impactor ejection device and an impactor; the monitoring unit includes: a first camera and an impactor speed meter; wherein, The battery bracket is used to support the battery clamp; The battery sample is used as a test object and is fixed by the battery fixture; The impactor ejection device is placed at a first set distance from the battery sample and is used to eject the impactor in a direction perpendicular to the battery plate; the impactor velocimeter is used to monitor the speed of the impactor during the ejection process; The first camera is placed at a second set distance from the battery sample, and is used to record phenomena occurring in the battery sample after the impactor penetrates the battery sample, and the phenomena are used to evaluate the safety level of the battery sample when it is hit by the impactor; Wherein, the safety level includes level three safety, level two safety, level one safety, level one danger, level two danger, and level three danger, and each safety level is determined in the following manner: if it is detected that only a perforation of the battery surface is caused by an impactor, and the internal structure of the battery is not changed, the safety level of the battery is determined to be level three safety; if it is detected that only a perforation of the battery surface is caused by an impactor, and the internal structure of the battery is changed, the safety level of the battery is determined to be level two safety; if a perforation of the battery surface is detected by an impactor, and a non-toxic or harmless gas or liquid leakage is detected in the battery, the safety level of the battery is determined to be level one safety; if a perforation of the battery surface is detected by an impactor, and a toxic or harmful gas or liquid leakage is detected in the battery, the safety level of the battery is determined to be level one danger; if a perforation of the battery surface is detected by an impactor, and an open flame is detected, the safety level of the battery is determined to be level two danger; if a perforation of the battery power generation surface is detected by an impactor, and an open flame and explosion are detected, the safety level of the battery is determined to be level three danger; Among them, the phenomena that occur in the battery sample after being hit by the impactor include one or more of the following: The battery surface is perforated by impact objects, the internal structure is changed, the battery leaks gas or liquid, the gas or liquid is toxic, an open flame occurs, and an explosion occurs after an open flame occurs; The battery clamp comprises: a first baffle, a frame, a second baffle and an alligator clip, wherein: The alligator clip is made of high temperature resistant material and frosted surface, the rear baffle is made of tungsten steel alloy, the frame is a steel plate with a hollowed-out central area, and is placed opposite to the second baffle; The first baffle plate and the second baffle plate are placed opposite to each other, and there is a gap between the first baffle plate and the second baffle plate for accommodating the battery sample; There are four alligator clips, which are used to clamp and fix the second baffle and the four top corners of the frame respectively; The first baffle is embedded in the outer surface of the frame, and is used to encapsulate the battery sample inside the battery fixture; The test system also includes: A temperature sensor, including six temperature probes, for detecting temperature changes of the battery sample at different times after being hit by an impactor; Among them, the measuring point of the first probe is arranged on the incident surface of the impactor, 3 cm away from the geometric center of the battery; the measuring point of the second probe is arranged on the exit surface of the impactor, 3 cm away from the geometric center of the battery; the measuring point of the third probe is arranged at the battery leakage valve; the measuring point of the fourth probe is arranged 12 cm above the battery; the measuring point of the fifth probe is arranged 18 cm above the battery; the measuring point of the sixth probe is arranged 30° to the left of the front of the battery and 14 cm away from the battery; The test system also includes: The smoke tester is arranged at a fourth set distance from the battery sample, and the angle formed by the line connecting the two points of the smoke tester and the battery sample and the line connecting the impactor outlet and the two points of the battery sample is 70°. The smoke tester is used to detect whether the battery sample generates smoke when it is hit by the impactor, so as to determine the safety level of the battery sample when it is hit by the impactor; The smoke tester is also used to test the following four indicators after the battery sample produces smoke, so as to determine the degree of damage of the battery sample, wherein the indicators include: smoke concentration, opacity, average particle diameter and particle composition. The degree of damage of the battery sample is determined by: The moment when the impactor enters the battery is taken as the test zero point, and the moment when the index data remain constant is taken as the test end point. The collection frequency of the smoke tester is 1 time / second. The degree of battery damage is obtained by drawing curves for the four indicators and comparing the highest point, lowest point, curve trend, curve rise and decrease rate of the four indicator curves of different batteries.

2. The system according to claim 1, characterized in that The test system also includes: A second camera is placed at a third set distance from the battery sample, and is used to record changes in the battery during the entire process from the start of the test to the end of the test; The change phenomena include one or more of the following: being hit by an impact object, battery falling, liquid leakage, smoking, burning, explosion, color of leaked liquid, changes in the liquid and the bracket after contact, color of smoke, diffusion range, color of flame, shape of flame, diameter of fireball, length of flame and the number of fragments after explosion.

3. The system according to claim 1, characterized in that The test system also includes: The infrared imager is arranged 3 meters away from the battery sample, and the angle formed by the line connecting the infrared imager and the battery sample and the line connecting the impactor exit and the battery sample is 45°.

4. The system according to claim 1, characterized in that There are two impactor velocimeters, namely a first impactor velocimeter and a second impactor velocimeter arranged in front and behind the impactor launching direction; The distance between the first impactor velocity meter and the second impactor velocity meter is 1 meter; The distance between the second impactor velocity meter and the impactor exit port is 1.5 meters; The distance between the impactor exit port and the battery incident surface is 8 meters.

5. The system according to claim 1, characterized in that: The angle formed by the line connecting the first camera and the battery and the line connecting the impactor exit and the battery is 70°.

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