Collision test method and collision test system for power battery

Abstract

The application provides a collision test method and a collision test system for a power battery. The method comprises the steps of: establishing a first simulation model of a whole vehicle equipped with the power battery and a collision object, performing a first collision simulation test based on the first simulation model, and determining a theoretical deformation or a theoretical contact stress of the power battery; establishing a second simulation model of a simulation trolley equipped with the power battery and adjusting the second simulation model until a deviation between a deformation or a contact stress of the power battery and the theoretical deformation or the theoretical contact stress is within a preset range when a second collision simulation test is performed based on the second simulation model, and recording preset collision working condition parameters of the simulation trolley at this time; designing a test trolley according to the second simulation model, and performing an actual collision test by means of the test trolley with the preset collision working condition parameters; and determining a voltage and a resistance of the power battery during the actual collision test, and comparing the voltage and the resistance with a predetermined voltage threshold and a predetermined resistance threshold, respectively.

Description

Technical Field

[0001] This invention relates to a collision test method for power batteries and a collision test system for performing the method. Background Technology

[0002] In new energy vehicles, such as electric vehicles and fuel cell vehicles, the power battery is usually located at the bottom of the vehicle body. Therefore, when the vehicle bottoms out, it may collide with obstacles on the road, leading to thermal runaway of the battery and, in severe cases, causing the power battery to catch fire or explode. In addition, in order to increase the capacity of the power battery, it is placed closer to the door sill in the lateral direction. In the event of a side collision, if the intrusion into the battery casing is large, it may also cause the cell to deform, thus leading to thermal runaway of the power battery.

[0003] To evaluate the crash performance of power batteries, a crash test method based on a manufactured vehicle is known in the prior art. However, since the relevant data are already determined after the vehicle is manufactured, it is difficult to provide targeted guidance for the design process. In addition, this vehicle-based crash test is costly. Summary of the Invention

[0004] Depending on the specific aspects, the object of the present invention is an improved method and system for crash testing of power batteries.

[0005] Furthermore, the present invention aims to solve or alleviate other technical problems existing in the prior art.

[0006] This invention addresses the aforementioned problems by providing a collision testing method and system for power batteries. Specifically, the method includes the following steps:

[0007] S100: Establish a first simulation model of the vehicle equipped with a power battery and the collision object, conduct a first collision simulation test based on the first simulation model, and determine the theoretical deformation or theoretical contact stress of the power battery.

[0008] S200: Establish a second simulation model of the simulation trolley equipped with the power battery and adjust the second simulation model until the deviation of the deformation or contact stress of the power battery from the theoretical deformation or the theoretical contact stress is within a preset range when a second collision simulation test is conducted based on the second simulation model, and record the preset collision condition parameters of the simulation trolley at this time.

[0009] S300: Design a test trolley based on the second simulation model, and conduct an actual collision test using the test trolley with the preset collision condition parameters;

[0010] S400: During the actual crash test, the voltage and resistance of the power battery are measured and compared with predetermined voltage and resistance thresholds, respectively.

[0011] According to one aspect of the present invention, the collision object is located below or to the side of the power battery.

[0012] According to one aspect of the collision test method of the present invention, in step S100, during the first collision simulation test, the theoretical deformation or theoretical contact stress of the casing and module of the power battery is determined.

[0013] According to one aspect of the present invention, in step S400, the actual deformation or actual contact stress of the battery casing and module in the actual collision test is measured and compared with the theoretical deformation or theoretical contact stress respectively. If the deviation between them exceeds a preset range, the process returns to step S200.

[0014] According to one aspect of the present invention, in the collision test method, in step S400, during the actual collision test, the actual deformation of the power battery is recorded by means of a camera device and / or the actual contact stress of the power battery is determined by means of a pressure sensor.

[0015] According to one aspect of the collision test method of the present invention, in step S100, during the first collision simulation test, the total energy absorbed by the casing and module of the power battery is also determined.

[0016] According to one aspect of the collision test method of the present invention, step S200 includes the following sub-steps:

[0017] S201: Match the mass and initial collision velocity of the simulated trolley until the deviation between the initial kinetic energy of the simulated trolley in the second collision simulation test and the total energy absorbed by the battery casing and module in the first collision simulation test is within a preset range.

[0018] S202: Adjust the collision angle of the simulation trolley until the deviation between the deformation or contact stress of the power battery and the theoretical deformation or contact stress is within a preset range during the second collision simulation test.

[0019] According to one aspect of the collision test method of the present invention, in step S400, during the actual collision test, the temperature of the power battery is measured and / or the leakage of the power battery is detected.

[0020] According to one aspect of the present invention, a collision test method is provided to aid in the determination of the temperature of a power battery using a thermal imager.

[0021] According to another aspect of the present invention, a crash test system capable of performing such a crash test method for a power battery is provided, comprising:

[0022] The first simulation module is configured to build a first simulation model of the whole vehicle and the collision object and to conduct a first collision simulation test based on the first simulation model.

[0023] The second simulation module is configured to construct a second simulation model of the simulated trolley and the colliding object and to conduct a second collision simulation test based on the second simulation model.

[0024] A test trolley, on which a power battery is fixed and configured to perform actual crash tests;

[0025] A testing device, which is fixed on the test trolley and configured to detect the voltage and resistance of the power battery in an actual crash test.

[0026] By combining crash simulation tests with actual crash tests using test sleds equipped with power batteries instead of manufactured complete vehicles, testing costs can be reduced and targeted guidance can be provided for the design process. Attached Figure Description

[0027] Referring to the accompanying drawings, the above and other features of the present invention will become apparent, wherein,

[0028] Figure 1 A flowchart of a collision test method according to one aspect of the present invention is shown;

[0029] Figure 2 It shows according to Figure 1 Sub-steps of the flowchart. Detailed Implementation

[0030] It is readily understood that, based on the technical solution of this invention, those skilled in the art can propose various interchangeable structural methods and implementations without altering the essential spirit of the invention. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative examples of the technical solution of this invention and should not be considered as the entirety of the invention or as limitations or restrictions on the technical solution of this invention.

[0031] The directional terms such as up, down, left, right, front, back, front, back, top, and bottom mentioned or possibly used in this specification are defined relative to the structures shown in the accompanying drawings. These are relative concepts and may therefore vary depending on their location and usage. Therefore, these or other directional terms should not be interpreted as restrictive. Furthermore, the terms "first," "second," "third," and similar expressions are used for descriptive and distinguishing purposes only and should not be construed as indicating or implying the relative importance of the corresponding components.

[0032] refer to Figure 1 The diagram illustrates a flowchart of a crash test method according to the present invention, which can be used to evaluate the crash performance of a power battery. Here, the power battery is not limited to lithium-ion batteries; it can also include fuel cells (e.g., hydrogen fuel cells), supercapacitors, or aluminum-air batteries. Furthermore, this power battery can be used not only in pure electric vehicles but also in hybrid electric vehicles. The crash test method according to the present invention includes the following steps:

[0033] S100: Establish a first simulation model of the vehicle equipped with a power battery and the collision object, conduct a first collision simulation test based on the first simulation model, and determine the theoretical deformation or theoretical contact stress of the power battery.

[0034] S200: Establish and adjust the second simulation model of the simulation trolley equipped with the power battery. When conducting the second collision simulation test based on the second simulation model, the deviation of the deformation amount or contact stress of the power battery from the theoretical deformation amount or the theoretical contact stress is within a preset range, and record the preset collision condition parameters of the simulation trolley at this time.

[0035] S300: Design a test trolley based on the second simulation model, and conduct an actual collision test using the test trolley with the preset collision condition parameters;

[0036] S400: During the actual crash test, the voltage and resistance of the power battery are measured and compared with predetermined voltage and resistance thresholds, respectively.

[0037] It should be noted that the step names mentioned above (and below) are only used to distinguish between steps and facilitate their reference, and do not represent the order of the steps. The flowcharts in the accompanying diagrams are merely examples of how this method is executed. Unless there is a clear conflict, the steps can be executed in various orders or simultaneously.

[0038] By combining crash simulation tests with actual crash tests using test sleds equipped with power batteries instead of manufactured complete vehicles, testing costs can be significantly reduced. Furthermore, if the parameters of the power battery itself or its assembly in the vehicle do not meet crash requirements, the design can be adjusted promptly and specifically.

[0039] The first simulation model in step S100 includes a complete vehicle model and a collision object (which can also be referred to as a barrier or obstacle) model. The complete vehicle model can include the body, chassis, interior, exterior, power battery, or other necessary additional components, and each component is assembled according to actual production requirements to better simulate the actual condition of the vehicle. The second simulation model in step S200 includes a simulation trolley model and the aforementioned collision object model. A power battery is mounted on the simulation trolley, arranged in the same manner as in the complete vehicle. It should be noted that steps S100 and S200 can, but are not mandatory, be performed on a CAE platform, CAD platform, or finite element analysis platform, and can, but are not mandatory, involve the Ls-Dyna solver.

[0040] Optionally, the impact object used in crash simulation tests and actual crash tests can be positioned below the power battery (especially on the road ahead), for example, it can be set as a stone block, a circular or cylindrical stone block with a certain mass and shape. In addition, the impact object can also be arranged on the side of the whole vehicle or sled, especially the power battery, for example, constructed as a side pillar.

[0041] In step S100, a first collision simulation test is conducted under preset collision conditions or collision conditions specified by relevant collision regulations. These collision conditions can involve collision speed, collision angle, and the shape and mass of the colliding object. For example, a first collision simulation test can be conducted based on Euro-NCAP, specifically, a vehicle model impacts a rigid side pillar with a diameter of 254 mm at a speed of 32 km / h. Alternatively, this first collision simulation test can also be conducted based on C-NCAP, US-NCAP, or C-IASI test conditions.

[0042] In the first collision simulation test, the deformation or contact stress of the battery is calculated based on the Ls-Dyna solver mentioned above and recorded as theoretical deformation and theoretical contact stress. Furthermore, when a power battery is subjected to a collision, its internal module structure deforms, leading to the failure of internal component materials, such as separator rupture or anode / cathode material fracture, thereby triggering an internal short circuit. This internal short circuit generates a large amount of Joule heat and a large amount of gas, causing a rapid increase in internal pressure. When the pressure reaches the structural bearing limit, thermal runaway may occur. Therefore, optionally, in the first collision simulation test, the deformation or contact stress of the battery casing and module is calculated using the solver as theoretical deformation and theoretical contact stress.

[0043] In step S200, by matching the mass, center of gravity position, collision velocity, and collision angle of the simulated trolley, the second collision simulation test ensures that the deformation and contact stress of the battery, particularly the casing and module, are consistent with or within a preset range acceptable in the art (e.g., within 2.5%) of the first collision simulation test. Here, in the assembled state, the position of the power battery relative to the simulated trolley is consistent with the position of the power battery relative to the entire vehicle. For example, when an obstacle is located below the power battery (e.g., a rock), the height of the power battery relative to the ground remains consistent, and when the impact object is a side pillar, the distance of the power battery from the edge of the vehicle remains equal.

[0044] Optionally, in order to better match and adjust the second simulation model of the simulated sled so that the second collision simulation test can accurately test the collision performance of the power battery under the specified collision conditions, step S200 is divided into the following sub-steps:

[0045] S201: Match the mass and initial collision velocity of the simulated trolley until the initial kinetic energy of the simulated trolley in the second collision simulation test is consistent with the total energy absorbed by the casing and module of the power battery or its deviation is within a preset range, wherein the total energy absorbed by the casing and module can optionally be obtained in step S100 by means of a solver;

[0046] S202: Adjust the collision angle and / or center of gravity position of the simulated trolley until the deformation or contact stress of the power battery during the second collision simulation test is consistent with the theoretical deformation or contact stress, or the deviation is within a preset range. Thus, by distributing and controlling the number of variables, the simulated trolley in the second simulation model can be quickly matched.

[0047] In step S300, not only are the relevant parameters of the test trolley, such as size parameters, mass and center of gravity position, but also the arrangement of the power battery on the test trolley is kept consistent with the second simulation model.

[0048] In step S400, the changes in voltage and resistance of the power battery are measured during the actual crash test. These measurements include the voltage and resistance between the positive and negative terminals, the voltage and resistance when the positive terminal is grounded, and the voltage and resistance when the negative terminal is grounded. These measurements are then compared to specified voltage and resistance thresholds. If the changes in battery voltage are significant, the power battery is deemed unsuitable for the crash test and further improvements are made. For example, it can be specified that the voltage change during a crash should not exceed 50V.

[0049] Optionally, during actual crash tests, the temperature changes of the power battery can be monitored using thermal imagers or temperature measuring devices. Furthermore, cameras can be used to detect whether the power battery is leaking, such as electrolyte or coolant leakage. If the power battery temperature exceeds a preset range or leakage occurs, it is determined that the power battery does not meet the crash test requirements and further improvements will be made.

[0050] Furthermore, in step S400, the actual deformation of the power battery can be recorded using a camera device or the actual contact stress can be recorded using a pressure sensor, and these records can be compared with the preset deformation and preset contact stress from the first collision simulation test. Additionally, the actual deformation of the power battery during the actual collision test can be measured using a rangefinder, such as a laser rangefinder, radar, or other specialized equipment. If the deviation between these two measurements exceeds a preset range, the second simulation model is re-matched, and then the actual collision test is conducted. In this way, the test sled can accurately simulate the specified collision conditions and precisely test the collision performance of the power battery.

[0051] Furthermore, the present invention also relates to a crash test system for performing such a crash test method, comprising: a first simulation module configured to construct a first simulation model of a whole vehicle and a collision object and to perform a first crash simulation test based on the first simulation model; a second simulation module configured to construct a second simulation model of a simulation trolley and the collision object and to perform a second crash simulation test based on the second simulation model; a test trolley on which a power battery is fixed and configured to perform an actual crash test; and a detection device fixed on the test trolley and configured to detect the voltage and resistance of the power battery in the actual crash test. Please refer to the above explanation regarding the method according to the present invention.

[0052] It should be understood that all the above preferred embodiments are exemplary and not restrictive, and various modifications or variations made by those skilled in the art to the specific embodiments described above under the concept of the present invention should be within the legal protection scope of the present invention.

Claims

1. A collision test method for power batteries, characterized in that, Includes the following steps: S100: Establish a first simulation model of the vehicle equipped with a power battery and the collision object, conduct a first collision simulation test based on the first simulation model, and determine the theoretical deformation or theoretical contact stress of the power battery. S200: Establish a second simulation model of the simulation trolley equipped with the power battery and adjust the second simulation model until the deviation of the deformation or contact stress of the power battery from the theoretical deformation or the theoretical contact stress is within a preset range when a second collision simulation test is conducted based on the second simulation model, and record the preset collision condition parameters of the simulation trolley at this time. S300: Design a test trolley based on the second simulation model, and conduct an actual collision test using the test trolley with the preset collision condition parameters; S400: During the actual crash test, the voltage and resistance of the power battery are measured and compared with predetermined voltage and resistance thresholds, respectively.

2. The collision test method according to claim 1, characterized in that, The impacting object is located below or to the side of the power battery.

3. The collision test method according to claim 2, characterized in that, In step S100, during the first collision simulation test, the theoretical deformation or theoretical contact stress of the battery casing and module is determined.

4. The collision test method according to claim 3, characterized in that, In step S400, the actual deformation or actual contact stress of the battery casing and module in the actual collision test is measured and compared with the theoretical deformation or theoretical contact stress respectively. If the deviation between them exceeds the preset range, the process returns to step S200.

5. The collision test method according to claim 4, characterized in that, In step S400, during the actual collision test, the actual deformation of the power battery is recorded by means of a camera device or a laser rangefinder and / or the actual contact stress of the power battery is determined by means of a pressure sensor.

6. The collision test method according to any one of claims 1 to 5, characterized in that, In step S100, during the first collision simulation test, the total energy absorbed by the casing and module of the power battery is also determined.

7. The collision test method according to claim 6, characterized in that, Step S200 includes the following sub-steps: S201: Match the mass and initial collision velocity of the simulated trolley until the deviation between the initial kinetic energy of the simulated trolley in the second collision simulation test and the total energy absorbed by the battery casing and module in the first collision simulation test is within a preset range. S202: Adjust the collision angle of the simulation trolley until the deviation between the deformation or contact stress of the power battery and the theoretical deformation or contact stress is within a preset range during the second collision simulation test.

8. The collision test method according to any one of claims 1 to 5, characterized in that, In step S400, during the actual crash test, the temperature of the power battery is measured and / or whether the power battery is leaking is detected.

9. The collision test method according to claim 8, characterized in that, Thermal imaging devices are used to measure the temperature of power batteries.

10. A collision testing system capable of performing the collision testing method according to any one of claims 1 to 9, characterized in that, include: The first simulation module is configured to build a first simulation model of the whole vehicle and the collision object and to conduct a first collision simulation test based on the first simulation model. The second simulation module is configured to construct a second simulation model of the simulated trolley and the colliding object and to conduct a second collision simulation test based on the second simulation model. A test trolley, on which a power battery is fixed and configured to perform actual crash tests; A testing device, which is fixed on the test trolley and configured to detect the voltage and resistance of the power battery in an actual crash test.

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