Battery detection device and method

Abstract

The present invention provides a battery detection device and detection method for detecting parameters of thermal runaway of a power battery to be tested, including: a detection system, a variable volume box and a thermal runaway trigger system, wherein the detection system is used to detect parameters in the variable volume box, and the drive system is used to drive the drivable part. The beneficial effects of the present invention: through the sliding connection between the drivable part and the box body, the size of the enclosed space formed by the two can be controlled, and different charging environment space volumes can be selected for different types of power batteries to be tested, simulating the environmental parameters of the actual situation of the battery triggering thermal runaway, so that the data of the detection result is closer to the actual value, and the consequences of thermal runaway can be accurately analyzed, so that corresponding precautions can be taken when producing or assembling power batteries, thereby improving the safety of power batteries.

Description

Technical Field

[0001] The present invention relates to the field of power batteries, and in particular to a battery detection device and method. Background Art

[0002] At present, the safety problem of power batteries mainly lies in the thermal safety problem of batteries. In the existing technology, the controllable environmental parameters of the device for detecting battery thermal runaway are single. There are differences between the environmental parameters of the existing device and the actual environmental parameters. Only one type of power battery can be detected, and the types of power batteries that can be detected are very limited. Therefore, there is an urgent need for a detection device that can detect multiple types of power batteries. Summary of the invention

[0003] The main purpose of the present invention is to provide a battery detection device and method, aiming to solve the technical problem that existing devices are unable to detect thermal runaway of power batteries of various models.

[0004] The present invention provides a battery detection device for detecting parameters of thermal runaway of a power battery to be tested, comprising: a detection system, a drive system, a variable volume box and a thermal runaway trigger system, wherein the variable volume box is used to place the power battery to be tested, the detection system is connected to the variable volume box, the detection system is used to detect parameters in the variable volume box, and the thermal runaway trigger system is used to connect to the power battery to be tested to control the power battery to be tested to have a thermal runaway event;

[0005] The variable volume box includes a box body and a drivable part, the box body and the drivable part are slidably connected, the box body and the drivable part form an enclosed space, and when the drivable part slides relative to the box body within a preset stroke range, the volume of the enclosed space increases or decreases. The driving system is connected to the drivable part for driving the drivable part.

[0006] Furthermore, the thermal runaway trigger system includes a battery charging cabinet and a short-circuit machine, the battery charging cabinet and the short-circuit machine are respectively used to electrically connect to the power battery to be tested, the battery charging cabinet is used to simulate the charging condition of the power battery to be tested, and the short-circuit machine is used to simulate the short-circuit condition of the power battery.

[0007] Furthermore, the box body includes a front box cover and a protective cavity, the protective cavity is a cavity with openings at both ends, the front box cover is arranged at one end opening of the protective cavity, and the other end opening of the protective cavity is connected to the drivable part, and the front box cover, the protective cavity and the drivable part constitute the enclosed space.

[0008] Furthermore, the front box cover comprises a front box cover body and explosion-proof transparent glass, the front box cover body is provided with a window, and the explosion-proof transparent glass is provided on the window.

[0009] Furthermore, the interior of the protective cavity is coated with a ceramic heat insulation layer.

[0010] Furthermore, the battery detection device also includes a carrier gas system, which is connected to the enclosed space and is used to control the air pressure in the enclosed space.

[0011] Furthermore, the carrier gas system includes a vacuum pump and a compressed air source, the vacuum pump and the compressed air source are respectively connected to the confined space, the vacuum pump is used to extract vacuum from the confined space, and the compressed air source is used to input gas into the confined space.

[0012] Furthermore, a load carrier is also provided on the drivable part, and the load carrier is provided at one end of the drivable part close to the inside of the variable volume box, and the load carrier is used to carry the power battery to be tested.

[0013] Furthermore, the detection system includes a data acquisition device and a gas concentration sensor, the gas concentration sensor is arranged inside the variable volume box, and the data acquisition device is connected to the gas concentration sensor to collect information collected by the gas concentration sensor.

[0014] Furthermore, a measuring gas circuit valve is also provided on the variable volume box.

[0015] The present invention also provides a power battery detection method, which is implemented by the above-mentioned battery detection device, comprising:

[0016] Get the model of the power battery to be tested;

[0017] adjusting the size of the enclosed space according to the model;

[0018] Turning on the thermal runaway trigger system to perform thermal runaway processing on the power battery to be tested;

[0019] The detection system is used to detect relevant parameters in the confined space.

[0020] The beneficial effects of the present invention are as follows: by slidingly connecting the drivable part with the box body, the size of the enclosed space formed by the two can be controlled, and different charging environment space volumes can be selected for different types of power batteries to be tested, and the environmental parameters of the actual situation of the battery triggering thermal runaway are simulated, and the volume of the enclosed space is adjusted to make the data of the test result closer to the actual value, and accurately analyze the consequences of thermal runaway, so that corresponding precautions can be taken when producing or assembling power batteries, thereby improving the safety of power battery use. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of an embodiment of a battery detection device of the present invention;

[0022] Figure 2 It is a partial structure enlarged schematic diagram of an embodiment of a battery detection device of the present invention;

[0023] Figure 3 It is a flow chart of an embodiment of a power battery detection method of the present invention.

[0024] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0025] 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.

[0026] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly. The connection can be a direct connection or an indirect connection.

[0027] The term "and / or" in this article is only a description of the association relationship of associated objects, indicating that there may be three relationships. For example, A and B can represent three situations: A exists alone, A and B exist at the same time, and B exists alone.

[0028] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0029] Reference Figure 1 The present invention proposes a battery detection device for detecting a power battery 100 to be tested, comprising: a detection system 10, a drive system 500, a variable volume box 300 and a thermal runaway trigger system 21, wherein the variable volume box 300 is used to place the power battery 100 to be tested, the detection system 10 is connected to the variable volume box 300, the detection system 10 is used to detect parameters (such as heat data, air pressure, etc.) in the variable volume box 300, and the thermal runaway trigger system 21 is used to be connected to the power battery 100 to be tested, and control the power battery 100 to be tested to have a thermal runaway event; the variable volume box 300 comprises a box body 30 and a drivable part 36, the box body 30 and the drivable part 36 are slidably connected, the box body 30 and the drivable part 36 form a closed space, when the drivable part 36 slides relative to the box body 30 within a preset stroke range, the volume of the closed space increases or decreases accordingly, and the drive system 500 is connected to the drivable part 36, and is used to drive the drivable part 36.

[0030] In this embodiment, the size of the enclosed space formed by the drivable part 36 and the box body 30 can be controlled by slidingly connecting the two. Different charging environment space volumes can be selected for different types of power batteries 100 to be tested, and the environmental parameters of the actual situation of the battery triggering thermal runaway are simulated to adjust the volume of the enclosed space so that the data of the test result is closer to the actual value. The shape of the box body 30 is preferably prismatic or cylindrical, so that the drivable part can slide on the box body 30 without the problem of poor sealing.

[0031] In this embodiment, the thermal runaway trigger system 21 includes a battery charging cabinet and a short-circuit machine. The battery charging cabinet and the short-circuit machine are electrically connected to the power battery 100 to be tested, respectively. The battery charging cabinet is used to simulate the charging condition of the power battery 100 to be tested, and the short-circuit machine is used to simulate the short-circuit condition of the power battery 100. The battery charging cabinet can be used to simulate various aspects of the battery, such as overcharging, fast charging, and other situations that may cause thermal runaway. The short-circuit machine can be used to simulate the situation where the power battery 100 generates thermal runaway under the condition of short circuit, so as to simulate the situation where the power battery 100 generates thermal runaway under actual conditions, which is helpful for analyzing the consequences of thermal runaway of the power battery 100 under actual conditions. In addition, an ammeter 22 and / or a voltmeter 23 can be connected in series in the circuit to detect the current and / or voltage when it is out of control. In addition, the thermal runaway trigger system 21 may also include a heating sheet, which is arranged on both sides of the power battery 100 to heat the power battery 100 and simulate the effect of excessively high external ambient temperature on the power battery 100. The model of the heating sheet can be set according to the size of the power battery 100. For example, a 72Ah square aluminum shell battery can use a 300W heating sheet. In this embodiment, please refer to Figure 1 The driving system 500 may include a driving box 52 and a telescopic rod 51. The telescopic rod 51 and the drivable part 36 are fixedly connected or detachably connected. The driving box 52 drives the drivable part 36 to extend and retract by driving the telescopic rod 51. The drivable part 36 should be in airtight contact connection with the interior of the box body 30, so that the box body 30 and the drivable part 36 can form an enclosed space. The volume of the variable volume box 300 can be changed by adjusting the position of the drivable part 36 by the telescopic rod 51.

[0032] In this embodiment, the box body 30 includes a front box cover 31 and a protective cavity 32. The protective cavity 32 is a hollow cavity with openings at both ends. The front box cover 31 is set at one end of the protective cavity 32. The other end of the protective cavity 32 is connected to the drivable part 36. The front box cover 31, the protective cavity 32 and the drivable part 36 constitute a closed space. It should be noted that the telescopic rod 51 can drive the drivable part 36 to separate from the box body 30 to facilitate loading the power battery 100 to be tested. It can also be done by removing the front box cover 31 and then putting the power battery 100 in, preferably in a place close to the power connection position of the thermal runaway trigger system 21. The protective cavity 32 preferably has an inner cavity size of 400mm (D) × 600mm (H), and is made of a stainless steel plate with a thickness of 10mm.

[0033] In this embodiment, the front box cover 31 includes a front box cover body 312 and an explosion-proof transparent glass 311. A window is provided on the front box cover body 312, and the explosion-proof transparent glass 311 is provided on the window. Through the window, the process of thermal runaway of the power battery 100 can be observed, and then the causes, phenomena and consequences of thermal runaway of the power battery 100 can be comprehensively analyzed, and corresponding measures can be taken for the prevention and solution of thermal runaway of the power battery 100, so as to make the assembly and use of the power battery 100 safer. The front box cover 31 and the protective cavity 32 can be fixedly connected by means of threads, etc., and the window diameter can be set to 170 mm for subsequent observation.

[0034] In this embodiment, the battery detection device also includes a carrier gas system 400, which is connected to the enclosed space and is used to control the air pressure in the enclosed space. Specifically, the carrier gas system 400 includes a vacuum pump 48 and a compressed air source 47, and the vacuum pump 48 and the compressed air source 47 are respectively connected to the enclosed space, wherein the connection method of the vacuum pump 48 and the compressed air source 47 to the enclosed space is not limited, and can be used to achieve vacuuming and inputting gas to the enclosed space.

[0035] In a specific embodiment, the carrier gas system 400 also includes a first gas circuit 45, a second gas circuit 43, a main gas circuit 41, a first valve 46, a second valve 44 and a third valve 42. The first gas circuit 45 is connected to the second gas circuit 43 and is respectively connected to the main gas circuit 41. The vacuum pump 48 is connected to the space inside the box through the second gas circuit 43 and the main gas circuit 41 in turn. A second valve 44 is provided in the second gas circuit 43. The second valve 44 is used to control the connection and disconnection between the main gas circuit 41 and the second gas circuit 43. The compressed air source 47 is connected to the space inside the box through the first gas circuit 45 and the main gas circuit 41 in turn. A first valve 46 is provided in the first gas circuit 45. The first valve 46 is used to control the connection and disconnection between the compressed air source 47 and the main gas circuit 41. The main gas circuit 41 is provided with a third valve 42. The third valve 42 is used to control the connection and disconnection between the second gas circuit 43 and the first gas circuit 45 and the main gas circuit 41.

[0036] Specifically, when vacuuming is required, the first valve 46 is closed, and the second valve 44 and the third valve 42 are opened. The gas inside the variable volume box 300 is extracted through the first air path 45 and the main air path 41 by the vacuum pump 48. When the variable volume box 300 needs to be filled with inert gas, the first valve 46 and the third valve 42 are opened, the second valve 44 is closed, and the variable volume box 300 is inflated through the second air path 45 and the main air path 41 by the compressed air source 47. Of course, air can also be input through the compressed air source 47. The purpose of inputting inert gas is to analyze the gas generated by thermal runaway of the power battery 100 without being interfered by other gases.

[0037] In this embodiment, the interior of the protective cavity 32 is coated with a ceramic insulation layer 7. Since the thermal conductivity of general metal materials is very good, there is a large error in the heat generated by the thermal runaway of the power battery 100. Therefore, a ceramic insulation layer is coated inside the hollow, and its exterior can be made of high-strength explosion-proof steel. On the one hand, it maintains the strength of the variable volume box 300, and on the other hand, it further hinders the heat transfer speed, making the detected heat data closer to the actual value. In some preferred embodiments, a ceramic insulation layer 7 can also be coated on the front box cover 31 and the side of the drivable part 36 close to the enclosed space, so that the insulation effect inside the variable volume box 300 is better.

[0038] In this embodiment, please refer to Figure 2 , the drivable part 36 is also provided with a carrier bracket 33, which is arranged at one end of the drivable part 36 close to the inside of the variable volume box 300, and the carrier bracket 33 is used to carry the power battery 100 to be tested. As mentioned above, the drivable part 36 and the box body 30 are detachable, that is, the drivable part 36 can be separated from the box body 30. When placing the power battery 100 to be tested, the drivable part 36 can be separated from the box body 30, and the drivable part 36 can be contacted and connected with the box body 30 after the power battery 100 is placed. In addition, the two wires connected to the thermal runaway trigger system 21 can be arranged to extend into the carrier bracket 33 to connect with the power battery 100, that is, when the drivable part 36 is separated from the box body 30, the power battery 100 to be tested can be assembled on the carrier bracket 33, which is convenient for the operator to assemble. A partition 34 may be provided outside the load carrier 33, and the partition 34 is provided between the external environment and the load carrier 33, and acts as a heat insulation layer between the external environment and the load carrier 33, and also prevents the power battery 100 from spraying chemicals to other places after thermal runaway and is difficult to clean. In order to make the load carrier 33 more secure in the confined space.

[0039] Please refer to Figure 1 In this embodiment, the carrier bracket 33 can be just a plate, which is fixedly connected to the partition 34 and can carry the power battery 100. In a preferred embodiment, the carrier bracket 33 can also be composed of multiple plates, and the multiple plates and the partition 34 form an unclosed box body. The multiple plates and the partition 34 in the box body can effectively prevent the power battery 100 from spraying chemicals to other places after thermal runaway, and the unclosed side can facilitate observation by operators.

[0040] Please refer again Figure 2The detection system 10 also includes a heater 17 and a battery cell clamp 18. The battery cell clamp 18 is arranged on the carrier bracket 33. Since the power battery 100 is inconvenient to fix, the battery cell clamp 18 is used to clamp the power battery 100 so that it can be stably placed on the carrier bracket 33. In addition, a heater 17 can be arranged close to the power battery 100. The power battery 100 is heated by the heater 17. The heater 17 can also be clamped by the battery cell clamp 18 so that the power battery 100 can be fully heated to simulate the situation of thermal runaway of the power battery 100.

[0041] In this embodiment, in order to ensure the airtightness of the enclosed space, a sealed power connection line socket 6 can be set. When the connecting wire between the power battery 100 and the thermal runaway trigger device 21 passes through the drivable part 36 and the partition 34, a sealed power connection line socket 6 can be set on the drivable part 36 and the partition 34, which can reduce the heat loss caused by the need for the wire to pass through the drivable part 36 and the partition 34.

[0042] In this embodiment, the detection system 10 includes a data acquisition device 11 and a gas concentration sensor 14. The gas concentration sensor 14 is arranged inside the box. The data acquisition device 11 is connected to the gas concentration sensor 14 to collect information collected by the gas concentration sensor 14. In addition, a temperature sensor 13 may also be included. The temperature sensor 13 is used to detect the temperature on the surface of the power battery 100 to be tested. The temperature sensor 13 is connected to the data acquisition device 11. The data acquisition device 11 integrates the data for subsequent viewing by the operator. It should be noted that the data acquisition device 11 can collect all the data of the gas concentration sensor 14 and the temperature sensor 13 within a set time, not just the data at a certain moment.

[0043] In this embodiment, a pressure sensor 12 is also included, which is arranged inside the box and is used to detect the air pressure inside the box. Similarly, the pressure sensor 12 can be connected to the data acquisition device 11, so that the data acquisition device 11 collects the changes in the internal pressure of the variable volume box 300 within a set time, and the data acquisition device 11 can also be connected to the drive box 52 for data. During the constant pressure test, the volume of the variable volume box 300 can be adjusted according to the detected internal pressure of the variable volume box 300 to maintain the internal pressure of the variable volume box 300 unchanged.

[0044] In this embodiment, a measuring and analyzing device 16 and an exhaust gas recovery device 15 are also provided on the variable volume box 300. The gas generated after thermal runaway can be collected by measuring the gas circuit valve 16, so that the gas composition can be analyzed, and the gas generated by thermal runaway can be recovered by the exhaust gas recovery device 15 to avoid polluting the environment. In addition, the generated gas can also be passed into water to detect the pH value of the exhaust gas solution. In addition, a safety explosion-proof valve is also provided on the protective cavity 32. When the air pressure inside the variable volume box 300 reaches the safe preset value range, it will explode to protect the safety of the entire machine. A camera can also be set to detect the internal situation and record the start and end time of thermal runaway. Furthermore, the camera can also use high-definition infrared thermal imaging monitoring to record the combustion behavior of the thermal runaway flame.

[0045] The operation steps for performing constant capacity detection on the power battery 100 are as follows:

[0046] The drivable part 36 is driven to a certain position by the driving box 52 and then fixed, so that the internal space of the variable volume box 300 maintains a certain volume, the first valve 46 is closed, the second valve 44 and the third valve 42 are opened, the vacuum pump 48 power supply is turned on to evacuate the variable volume box 300, the second valve 44 is closed, the first valve 46 is opened, and the compressed air source 47 valve is opened to fill the test cavity in the variable volume box 300 with inert gas, and when the air pressure value in the connected variable volume box 300 reaches 0.1MPa (P0) (close to the atmospheric pressure), the inert gas connecting valve is closed; after the ambient temperature (T0) in the test cavity reaches stability, the battery charging cabinet or the short-circuit machine switch is turned on, and the data acquisition device 11 is turned on to monitor and record the air pressure, temperature and gas concentration in the cavity, and the circuit is immediately cut off when the surface temperature of the test sample exceeds 250°C; after standing for a period of time, the ambient temperature (Te) and air pressure value (Pe) in the test cavity reach stability.

[0047] The total molar amount of gas produced by thermal runaway can be estimated using the following calculation formula:

[0048]

[0049] Where R is the molar gas constant R = 8.314 J / (mol*K)

[0050] According to the camera's recorded observations, the thermal runaway gas release time (t) can be obtained, and the thermal runaway gas production rate (n / t) can be obtained based on the total molar amount of gas produced as above.

[0051] After the test, the measuring gas circuit valve 16 is opened, and the collecting device collects the gas generated by thermal runaway to analyze its components and content. At the same time, by monitoring the gas concentration during the thermal runaway process, it can further provide supporting data for the analysis of the thermal runaway failure mechanism.

[0052] After the test is completed, the measuring gas circuit valve 16 is opened to pass the gas generated by thermal runaway into distilled water, and the pH value of the solution containing the exhaust gas can be measured.

[0053] Based on high-definition infrared thermal imaging monitoring, the combustion behavior characteristics of the thermal runaway jet flame of the test power battery 100 under different thermal runaway triggering conditions and the thermal runaway propagation law of the power battery pack can be studied.

[0054] Reference Figure 1-3 The present invention also provides a power battery 100 detection method, which is implemented by the above-mentioned battery detection device, including:

[0055] S1: Obtain the model of the power battery 100 to be tested;

[0056] S2: adjusting the size of the enclosed space according to the model;

[0057] S3: starting the thermal runaway trigger system 21 to perform thermal runaway processing on the power battery 100 to be tested;

[0058] S4: Detect relevant parameters in the enclosed space through the detection system 10.

[0059] As described in the above step S1, the model of the power battery 100 to be tested is obtained. The parameters of the model can be manually input by the experimenter, or the power battery 100 can be connected with other detection equipment, such as the voltmeter 23 to obtain its voltage, and the ammeter 22 to obtain its current. Since different power batteries 100 have different voltages at both ends and different currents, the relevant data can be obtained by detecting them. In some embodiments, the size of the power battery 100 can also be obtained by photographing. Since its size and type may also correspond, its size can be detected, and can be specifically determined according to setting different types of parameters.

[0060] As described in the above step S2, the correspondence between the model and the size of the enclosed space is set internally in advance. After the model of the power battery 100 to be tested is obtained, the size of the enclosed space is adjusted to match the model of the power battery 100 to be tested through the drive system and the drivable part 36. That is, if the power battery 100 is a larger model, the drivable part can be driven to move outward to expand the volume of the enclosed space. If the power battery is a smaller model, the drivable part can be driven to move inward to reduce the volume of the enclosed space. Of course, since the enclosed space is a prismatic or cylindrical shape, its cross-sectional area is unchanged, and its volume only depends on the distance between the drivable part 36 and the front box cover 31. Therefore, it is possible to establish a correspondence between the model of the power battery 100 and the distance. When the model of the power battery 100 is detected, the drivable part is moved to a distance corresponding to the front box cover 31.

[0061] As described in the above step S3, the thermal runaway processing is performed on the power battery 100 to be tested through the thermal runaway trigger system 21. The thermal runaway processing can be three different methods: heating, short circuit and overcharging. That is, the power battery 100 can be overcharged or fast charged by a battery charging cabinet to cause thermal runaway of the power battery 100, or the power battery 100 can be short-circuited by a short-circuit machine to cause thermal runaway, or the power battery 100 can be directly heated by a heater to cause thermal runaway.

[0062] As described in the above step S4, the detection system 10 is used to detect relevant parameters in the enclosed space, such as detecting the temperature through a temperature sensor, detecting the gas composition after thermal runaway, the pH value, etc. The specific detection can be carried out by referring to the various detection devices included in the above detection system 10, which will not be repeated here.

[0063] Before the above step S3, the following steps are also included:

[0064] S201: evacuating the enclosed space by a vacuum pump;

[0065] S202: Detecting whether the vacuum degree in the enclosed space reaches a set value;

[0066] S203: If yes, turn off the vacuum pump.

[0067] As described in the above steps S201-S203, if the air in the enclosed space needs to be discharged, the enclosed space can be evacuated by the vacuum pump 48. The degree of extraction can be measured by the vacuum degree. The vacuum degree can be detected by the gas concentration sensor 14. When the concentration of the gas is lower than the set value, it can be considered that the vacuum degree has reached the set value, and then it can be considered that the air in the enclosed space has been completely extracted. In addition, it can be tested by a vacuum tester to directly detect the internal vacuum degree. At this time, the vacuum pump 48 is turned off to avoid wasting excess electricity, and it also prepares for the subsequent filling of inert gas through the compressed air source 47.

[0068] After the above step S203, the following steps are included:

[0069] S204: Open the valve of the compressed air source 47 to fill the enclosed space with inert gas;

[0070] S205: Detecting whether the air pressure value in the enclosed space has reached a preset air pressure value;

[0071] S206: If yes, close the compressed air source 47.

[0072] As described in the above steps S204-S206, after the internal air has been completely extracted, if you want to detect the thermal runaway parameters under a certain air pressure, you can pre-set a preset air pressure value, and then fill the enclosed space with inert gas through the compressed air source 47 until the internal air pressure reaches the preset air pressure value. The detection method can also detect the concentration of the internal gas through the gas concentration sensor 14, and the concentration of the gas is proportional to the internal air pressure value, so the internal air pressure value can be detected by detecting the concentration of the gas. On the other hand, the internal pressure in the enclosed space can also be directly detected by the pressure sensor. The preset air pressure value can be input by itself. When the detection reaches this value, the compressed air source 47 is controlled to be closed. For example, the general test is the situation when the atmospheric pressure is at atmospheric pressure, that is, after the inert gas is filled to the atmospheric pressure (about 0.1Mpa), the compressed air source 47 is closed. The compressed air source 47 can be closed directly by closing the valve on the compressed air source 47, or by closing the valve set on the passage between the compressed air source 47 and the enclosed space.

[0073] The above step S4 comprises:

[0074] S401: Detect whether the temperature difference within a set time is less than a preset value;

[0075] S402: If yes, then the detection system 10 detects relevant parameters in the enclosed space.

[0076] As described in the above steps S401-S402, after thermal runaway occurs, the temperature in the enclosed space is not constant, so it is generally necessary to wait for a short period of time before detecting the internal parameters (especially the temperature parameters). Whether the temperature in the enclosed space is constant can be determined by whether the temperature changes little within the set time, that is, whether the change is less than the preset value. If the change is less than the preset value, it means that the temperature in the enclosed space has become constant, and the internal parameters can continue to be detected. If the temperature difference is greater than the preset value, it means that the temperature in the enclosed space has not yet been balanced, so it is necessary to continue waiting for a while. In some cases, if the temperature difference is still not less than the set value after the set time, until the temperature difference is equal to or close to the room temperature, it may be that the insulation in the enclosed space is poor, or the enclosed space is not formed.

[0077] The beneficial effects of the present invention are as follows: by slidingly connecting the drivable part 36 with the box body 30, the size of the enclosed space formed by the two can be controlled. Different charging environment space volumes can be selected for different types of power batteries 100 to be tested. The environmental parameters of the actual situation of the battery triggering thermal runaway are simulated, and the volume of the enclosed space is adjusted to make the data of the test result closer to the actual value, and the consequences of thermal runaway are accurately analyzed, so that corresponding precautions can be taken during the production or assembly of the power battery 100, thereby improving the safety of the power battery 100.

[0078] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the claims of the present invention.

Claims

1. A battery detection device for detecting parameters of thermal runaway of a power battery to be tested, characterized in that: include: A detection system, a drive system, a variable volume box and a thermal runaway trigger system, wherein the variable volume box is used to place the power battery to be tested, the detection system is connected to the variable volume box, the detection system is used to detect parameters in the variable volume box, the parameters include air pressure, and the thermal runaway trigger system is used to connect to the power battery to be tested to control the power battery to be tested to have a thermal runaway event; The variable volume box includes a box body and a drivable part, the box body and the drivable part are slidably connected, the box body and the drivable part form an enclosed space, when the drivable part slides relative to the box body within a preset stroke range, the volume of the enclosed space increases or decreases, and the driving system is connected to the drivable part for driving the drivable part.

2. The battery testing device according to claim 1, characterized in that: The thermal runaway trigger system includes a battery charging cabinet and a short-circuit machine, the battery charging cabinet and the short-circuit machine are respectively used to be electrically connected to the power battery to be tested, the battery charging cabinet is used to simulate the charging condition of the power battery to be tested, and the short-circuit machine is used to simulate the short-circuit condition of the power battery.

3. The battery testing device according to claim 1, characterized in that: The box body includes a front box cover and a protective cavity, the protective cavity is a cavity with openings at both ends, the front box cover is arranged at one end opening of the protective cavity, and the other end opening of the protective cavity is connected to the drivable part, and the front box cover, the protective cavity and the drivable part constitute the enclosed space.

4. The battery testing device according to claim 3, characterized in that: The front box cover comprises a front box cover body and explosion-proof transparent glass. A window is arranged on the front box cover body, and the explosion-proof transparent glass is arranged on the window.

5. The battery testing device according to claim 3, characterized in that: The interior of the protection cavity is coated with a ceramic heat insulation layer.

6. The battery testing device according to claim 1, characterized in that: The battery detection device further includes a carrier gas system, which is connected to the enclosed space and is used to control the air pressure in the enclosed space.

7. The battery testing device according to claim 6, characterized in that: The carrier gas system includes a vacuum pump and a compressed air source, wherein the vacuum pump and the compressed air source are respectively connected to the enclosed space, the vacuum pump is used to extract vacuum from the enclosed space, and the compressed air source is used to input gas into the enclosed space.

8. The battery testing device according to claim 1, characterized in that: The drivable part is also provided with a load-carrying bracket, which is arranged at one end of the drivable part close to the inside of the variable-volume box, and is used to carry the power battery to be tested.

9. The battery testing device according to claim 1, characterized in that: The detection system includes a data acquisition device and a gas concentration sensor. The gas concentration sensor is arranged inside the variable volume box. The data acquisition device is connected to the gas concentration sensor and is used to collect information collected by the gas concentration sensor.

10. A detection method, implemented by the battery detection device according to any one of claims 1 to 9, characterized in that: include: Get the model of the power battery to be tested; adjusting the size of the enclosed space according to the model; Turning on the thermal runaway trigger system to perform thermal runaway processing on the power battery to be tested; The detection system is used to detect relevant parameters in the confined space.

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