Stress threshold determination method and battery pack failure risk judgment method

Abstract

The invention relates to the technical field of battery testing, and discloses a stress threshold determination method and a battery pack failure risk judgment method, and the method comprises the steps: carrying out the random vibration simulation of a simulation model based on a preset vibration load spectrum, and obtaining the maximum preset stress and a corresponding target position; based on a preset vibration load spectrum, a random vibration test of a preset duration is carried out on a test object, whether the target position is cracked is judged, and the test object corresponds to the simulation model; a preset vibration load spectrum is adjusted according to the cracking result, and random vibration simulation and a random vibration test are sequentially carried out based on the adjusted vibration load spectrum; and judging whether the cracking results corresponding to the adjacent random vibration tests change or not, and if so, determining a stress threshold value according to the simulation results corresponding to the adjacent random vibration simulation. According to the method, a simulation and test successive approximation method can be adopted, the random vibration stress threshold value is determined, the accuracy of simulation evaluation is improved, and great transition design and design defects are avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of battery testing, and in particular to a method for determining a stress threshold and a method for determining the failure risk of a battery pack. Background Art

[0002] During the development of new energy vehicle battery packs, the battery packs need to undergo random vibration tests to verify their vibration durability performance. Using simulation methods for virtual verification is a necessary task in the development process, which can greatly reduce the number of tests and improve the test pass rate.

[0003] However, the evaluation of random vibration simulation results is a major challenge. Currently, the stress threshold of the simulation results is used to determine the evaluation results. However, the evaluation standards adopted by most companies are relatively rough and inaccurate. They are either conservative or radical, which leads to reduced accuracy of random vibration simulation and ultimately inaccurate battery pack test results. Summary of the invention

[0004] In view of this, the present invention provides a method for determining a stress threshold and a method for judging the failure risk of a battery pack, so as to solve the problem that the evaluation criteria of random vibration simulation are inaccurate, resulting in reduced accuracy of random vibration simulation and inaccurate battery pack test results.

[0005] In a first aspect, the present invention provides a method for determining a stress threshold, the method comprising:

[0006] Performing random vibration simulation on the simulation model based on a preset vibration load spectrum, and obtaining a maximum preset stress and a target position corresponding to the maximum preset stress in the simulation model;

[0007] Performing a random vibration test of a preset duration on the test object based on a preset vibration load spectrum, and determining whether cracks occur at a target position of the test object, wherein the test object corresponds to the simulation model;

[0008] The preset vibration load spectrum is adjusted according to the cracking result, and random vibration simulation is performed on the simulation model based on the adjusted vibration load spectrum, and random vibration test is performed on the test object;

[0009] It is determined whether the cracking results corresponding to the adjacent random vibration tests have changed. If so, the stress threshold is determined according to the simulation results of the corresponding adjacent random vibration simulations.

[0010] The method for determining the stress threshold provided in the embodiment of the present invention performs random vibration simulation on the simulation model corresponding to the test object based on the preset vibration load spectrum to determine the maximum preset stress and the corresponding target position, and performs random vibration test on the test object based on the preset vibration load spectrum to determine whether cracking occurs at the target position of the test object. If cracking occurs, the preset vibration load spectrum is adjusted, and the random vibration simulation and random vibration test are repeated until the cracking results corresponding to the adjacent random vibration tests change, and the stress threshold is determined according to the simulation results of the corresponding adjacent random vibration simulations. By performing random vibration tests on the battery pack test object and the corresponding simulation model, the present invention can use a method of gradual approximation of simulation and test to determine the random vibration stress threshold, improve the accuracy of simulation evaluation, avoid large-scale transition design and design deficiencies, and the test object corresponding to the simulation model can be set as a dummy model, and both the simulation model and the dummy model can be reused, thereby reducing the cost of simulation benchmarking.

[0011] In an optional embodiment, the preset vibration load spectrum is adjusted according to the cracking result, including: if cracking occurs, reducing the acceleration power spectrum density value of the preset vibration load spectrum from the first amplitude to the second amplitude according to a preset multiple step size; if cracking does not occur, increasing the acceleration power spectrum density value of the preset vibration load spectrum from the first amplitude to the third amplitude according to a preset multiple step size.

[0012] The present invention gradually changes the amplitude of the vibration load spectrum according to the step size, and can use the method of gradual approximation of simulation and experiment to determine the crack boundary of the test object in the real random vibration test, and at the same time correspondingly determine the maximum stress corresponding to the simulation model in the simulated random vibration. The crack boundary corresponds to the maximum stress, so that an accurate stress threshold can be obtained.

[0013] In an optional embodiment, it is determined whether the cracking results corresponding to adjacent random vibration tests have changed. If so, a stress threshold is determined according to the simulation results of the corresponding adjacent random vibration simulations, including: determining whether the cracking results corresponding to the adjacent random vibration tests have changed from cracking to non-cracked, or from non-cracked to cracked; if so, obtaining a first maximum preset stress in a first random vibration simulation corresponding to a random vibration test in which cracking occurred, and obtaining a second maximum preset stress in a second random vibration simulation corresponding to a random vibration test in which no cracking occurred; calculating a stress error between the first maximum preset stress and the second maximum preset stress, and if the stress error is less than a preset tolerance threshold, selecting the second maximum preset stress as the stress threshold.

[0014] The present invention can determine whether the simulation and the test are really close to the cracking boundary by making a tolerance judgment on the two maximum preset stresses of the cracking boundary, thereby further ensuring the accuracy and reliability of the stress threshold.

[0015] In an optional embodiment, after calculating the stress error between the first maximum preset stress and the second maximum preset stress, the method further includes: if the stress error is not less than a preset tolerance threshold, reducing the preset multiple step size, and returning to adjusting the preset vibration load spectrum according to the cracking result, and performing random vibration simulation on the simulation model in turn based on the adjusted vibration load spectrum, and performing random vibration testing on the test object.

[0016] The present invention can determine the random vibration stress threshold by adopting a method of gradual approximation of simulation and experiment through repeated experiments. The simulation model can be reused in the repeated experimental process. Moreover, if the test object is a dummy model of an equivalent battery pack, the dummy model can also be reused, thereby reducing the simulation benchmarking cost.

[0017] In a second aspect, the present invention provides a method for determining the risk of battery pack failure, the method comprising:

[0018] Perform a random vibration test on the battery pack for a preset duration based on a preset vibration load spectrum, and obtain a preset stress at any position on the battery pack;

[0019] Acquire a stress threshold, where the stress threshold is determined according to the method for determining the stress threshold of the first aspect or any corresponding embodiment thereof;

[0020] Compare the preset stress with the stress threshold to determine whether there is a risk of failure at any location.

[0021] The method for judging the failure risk of a battery pack provided by an embodiment of the present invention performs a random vibration test on the battery pack for a preset time based on a preset vibration load spectrum, compares the preset stress at any position of the battery pack with the stress threshold, and judges whether there is a failure risk at any position. The present invention judges the failure risk of a battery pack based on a predetermined stress threshold, and can accurately judge whether the battery pack has a failure risk, thereby providing an accurate parameter basis for the structural optimization or material optimization of the battery pack, making the battery pack put into use durable and improving the user experience and satisfaction.

[0022] In an optional embodiment, a random vibration test of a preset duration is performed on a battery pack based on a preset vibration load spectrum, including: determining a preset vibration time, and judging whether the preset vibration time is equal to a preset duration; if not, determining a preset acceleration coefficient, and converting the preset vibration load spectrum into an equivalent vibration load spectrum based on the preset vibration time, the preset duration and the preset acceleration coefficient; and performing a random vibration test on the battery pack for a preset vibration time based on the equivalent vibration load spectrum.

[0023] The present invention can provide an equivalent conversion method for vibration spectra of arbitrary duration and arbitrary amplitude through a benchmarking method for duration vibration spectra, so that a predetermined stress threshold can be used to evaluate the failure impact of arbitrary vibration spectra under arbitrary vibration duration on the battery pack, thereby increasing the scope of application of random vibration leveling standards.

[0024] In a third aspect, the present invention provides a device for determining a stress threshold, the device comprising: a first test module, used to perform random vibration simulation on a simulation model based on a preset vibration load spectrum, and obtain a maximum preset stress and a target position corresponding to the maximum preset stress in the simulation model; a second test module, used to perform a random vibration test of a preset duration on a test object based on a preset vibration load spectrum, and determine whether cracks occur at a target position of the test object, wherein the test object corresponds to the simulation model; a cyclic test module, used to adjust the preset vibration load spectrum according to the cracking result, and perform random vibration simulation on the simulation model in turn based on the adjusted vibration load spectrum, and perform a random vibration test on the test object; a threshold determination module, used to determine whether the cracking results corresponding to adjacent random vibration tests have changed, and if so, determine the stress threshold according to the simulation results of the corresponding adjacent random vibration simulations.

[0025] In a fourth aspect, the present invention provides a device for determining the failure risk of a battery pack, the device comprising: a third test module, used to perform a random vibration test on the battery pack for a preset duration based on a preset vibration load spectrum, and obtain a preset stress at any position on the battery pack; a threshold acquisition module, used to obtain a stress threshold, the stress threshold is determined according to the method for determining the random vibration simulation stress threshold according to the first aspect or any corresponding embodiment thereof; a risk judgment module, used to compare the preset stress with the stress threshold to determine whether there is a failure risk at any position.

[0026] In a fifth aspect, the present invention provides a computer device, comprising: a memory and a processor, the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the method for determining the stress threshold of the above-mentioned first aspect or any corresponding embodiment thereof, or the method for determining the failure risk of a battery pack of the above-mentioned second aspect or any corresponding embodiment thereof by executing the computer instructions.

[0027] In a sixth aspect, the present invention provides a computer-readable storage medium having computer instructions stored thereon, the computer instructions being used to enable a computer to execute the method for determining a stress threshold of the first aspect or any corresponding embodiment thereof, or the method for determining a battery pack failure risk of the second aspect or any corresponding embodiment thereof.

[0028] In the seventh aspect, the present invention provides a computer program product, including computer instructions, which are used to enable a computer to execute the method for determining the stress threshold of the above-mentioned first aspect or any corresponding embodiment, or the method for determining the failure risk of a battery pack of the above-mentioned second aspect or any corresponding embodiment. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 is a schematic flow chart of a method for determining a stress threshold according to an embodiment of the present invention;

[0031] Figure 2 is a schematic diagram of a real battery pack according to a method for determining a stress threshold value according to an embodiment of the present invention;

[0032] Figure 3 is a schematic diagram of equivalent mass blocks of modules of equal size according to a method for determining a stress threshold value in an embodiment of the present invention;

[0033] Figure 4 is a schematic diagram of equivalent mass blocks of modules of different sizes according to a method for determining a stress threshold value in an embodiment of the present invention;

[0034] Figure 5 is a flow chart of another method for determining a stress threshold according to an embodiment of the present invention;

[0035] Figure 6 is a schematic diagram of a specific flow chart of another method for determining a stress threshold according to an embodiment of the present invention;

[0036] Figure 7 is a schematic diagram of load spectrum adjustment of another method for determining a stress threshold according to an embodiment of the present invention;

[0037] Figure 8 is a flow chart of a method for determining a battery pack failure risk according to an embodiment of the present invention;

[0038] Fig. 9 is a schematic diagram of a specific flow chart of a method for determining a battery pack failure risk according to an embodiment of the present invention;

[0039] Fig.10 is an equivalent conversion diagram of a method for determining a battery pack failure risk according to an embodiment of the present invention;

[0040] Fig.11 is a structural block diagram of a device for determining a stress threshold according to an embodiment of the present invention;

[0041] Fig.12 is a structural block diagram of a device for determining a battery pack failure risk according to an embodiment of the present invention;

[0042] Fig.13 It is a schematic diagram of the hardware structure of a computer device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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 those skilled in the art without creative work are within the scope of protection of the present invention.

[0044] The embodiment of the present invention is applicable to the scenario of performing random vibration test on the battery pack based on a predetermined stress threshold to verify its vibration endurance performance. The embodiment of the present invention provides a method for determining the stress threshold, which achieves the effect of determining the precise stress threshold by a method of gradual approximation through simulation and experiment.

[0045] According to an embodiment of the present invention, an embodiment of a method for determining a stress threshold is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0046] In this embodiment, a method for determining a stress threshold is provided, which can be used in a mobile terminal, such as a computer, etc. Figure 1 is a flow chart of a method for determining a stress threshold according to an embodiment of the present invention. Figure 1 As shown, the process includes the following steps:

[0047] Step S101 : performing random vibration simulation on a simulation model based on a preset vibration load spectrum, and obtaining a maximum preset stress and a target position corresponding to the maximum preset stress in the simulation model.

[0048] Specifically, in the embodiment of the present invention, a real test object is preset, and the test object can be a real battery pack, such as Figure 2 As shown, the external box and internal battery module; in order to increase the repeatability of the test and save costs, the test object can also be set as an equivalent battery pack of the real battery pack, such as Figure 3As shown, the external box and the internal equivalent mass blocks of equal-sized modules. Further, the test object of the embodiment of the present invention is to be compared with the simulation, as long as the simulation model is consistent with the test object, the equivalent mass blocks of equal-sized modules can also be set as equivalent mass blocks of non-equal-sized modules, such as Figure 4 shown.

[0049] In some optional implementations, the embodiment of the present invention adopts a method of gradual approximation of simulation and experiment to determine the random vibration stress threshold. Therefore, after setting up the test object, it is necessary to construct a simulation model corresponding to the test object, and perform random vibration simulation on the simulation model based on the standard vibration load spectrum. Among them, the embodiment of the present invention does not specifically limit the standard vibration load spectrum, which can be the vibration PSD (Power Spectral Density) in the standard GB38031, the vibration PSD in the standard GB31467.3, or the enterprise standard vibration load of the enterprise. In the process of random vibration simulation, the 1σ stress value of each position of the simulation model is obtained, and the maximum 1σ stress and the target position corresponding to the maximum 1σ stress are obtained after the simulation is completed, and the relevant values ​​are recorded.

[0050] Step S102 , performing a random vibration test of a preset duration on the test object based on a preset vibration load spectrum, and determining whether cracks occur at a target position of the test object, wherein the test object corresponds to the simulation model.

[0051] Specifically, in an embodiment of the present invention, a standard vibration load spectrum is used to carry out a random vibration test on the test object. The vibration duration is T hours. At the same time, the target position corresponding to the maximum 1σ stress is marked on the test object. After the test, the target position is observed to see whether there are cracks or cracks. The specific vibration control process is a conventional technical means in this field and will not be described in detail here.

[0052] Step S103, adjusting the preset vibration load spectrum according to the cracking result, and performing random vibration simulation on the simulation model and random vibration test on the test object in sequence based on the adjusted vibration load spectrum.

[0053] Specifically, in the embodiment of the present invention, if there are no cracks or cracks, it proves that the test object can withstand the current degree of vibration, so the embodiment of the present invention uniformly increases the amplitude of the standard vibration load spectrum. Then, based on the vibration load spectrum with the increased amplitude, the simulation model is subjected to random vibration simulation to obtain the maximum 1σ stress and the target position corresponding to the maximum 1σ stress; then, based on the vibration load spectrum with the increased amplitude, a random vibration test is performed on the test object to observe whether there are cracks or cracks at the target position corresponding to the maximum 1σ stress.

[0054] In some optional implementations, if there are cracks or fissures, it proves that the test object cannot withstand the current degree of vibration. Therefore, the embodiment of the present invention uniformly reduces the amplitude of the standard vibration load spectrum. Then, based on the vibration load spectrum with the reduced amplitude, the simulation model is subjected to random vibration simulation to obtain the maximum 1σ stress and the target position corresponding to the maximum 1σ stress; then, based on the vibration load spectrum with the reduced amplitude, a random vibration test is performed on the new test object to observe whether there are cracks or fissures at the target position corresponding to the maximum 1σ stress. The embodiment of the present invention performs corresponding cycles on the random vibration simulation of the simulation model and the random vibration test of the test object, so as to achieve simulation benchmarking.

[0055] Step S104, determining whether the cracking results corresponding to the adjacent random vibration tests have changed, and if so, determining the stress threshold according to the simulation results of the corresponding adjacent random vibration simulations.

[0056] Specifically, in the embodiment of the present invention, after each cycle of random vibration simulation and random vibration test is completed, it is observed whether the cracking result after the random vibration test of the current cycle is the same as the cracking result after the random vibration test of the previous cycle. If there is no change, the standard vibration load spectrum is adjusted continuously; if the cracking results of two adjacent cycles change, including from cracking to no cracking, or from no cracking to cracking, the maximum preset stress obtained by the random vibration simulation in the two adjacent cycles is obtained, and the maximum preset stress of the cycle corresponding to no cracking is selected as the stress threshold, which is recorded as σ limit .

[0057] The method for determining the stress threshold provided in the embodiment of the present invention performs random vibration simulation on the simulation model corresponding to the test object based on the preset vibration load spectrum to determine the maximum preset stress and the corresponding target position, and performs random vibration test on the test object based on the preset vibration load spectrum to determine whether cracking occurs at the target position of the test object. If cracking occurs, the preset vibration load spectrum is adjusted, and the random vibration simulation and random vibration test are repeated until the cracking results corresponding to the adjacent random vibration tests change, and the stress threshold is determined according to the simulation results of the corresponding adjacent random vibration simulations. By performing random vibration tests on the battery pack test object and the corresponding simulation model, the present invention can use a method of gradual approximation of simulation and test to determine the random vibration stress threshold, improve the accuracy of simulation evaluation, avoid large-scale transition design and design deficiencies, and the test object corresponding to the simulation model can be set as a dummy model, and both the simulation model and the dummy model can be reused, thereby reducing the cost of simulation benchmarking.

[0058] In this embodiment, a method for determining a stress threshold is provided, which can be used in the above-mentioned mobile terminal, such as a computer, etc. Figure 5 is a flow chart of a method for determining a stress threshold according to an embodiment of the present invention. Figure 5 As shown, the process includes the following steps:

[0059] Step S501, perform random vibration simulation on the simulation model based on the preset vibration load spectrum, and obtain the maximum preset stress and the target position corresponding to the maximum preset stress in the simulation model. Figure 1 Step S101 of the illustrated embodiment will not be described in detail here.

[0060] Step S502: Perform a random vibration test of a preset duration on the test object based on a preset vibration load spectrum, and determine whether cracks occur at the target position of the test object, wherein the test object corresponds to the simulation model. Figure 1 Step S102 of the illustrated embodiment will not be described in detail here.

[0061] Step S503, adjusting the preset vibration load spectrum according to the cracking result, and performing random vibration simulation on the simulation model and random vibration test on the test object in sequence based on the adjusted vibration load spectrum.

[0062] Specifically, the above step S503 includes:

[0063] Step S5031: if cracking occurs, the acceleration power spectrum density value of the preset vibration load spectrum is reduced from the first amplitude to the second amplitude according to a preset multiple step size.

[0064] Specifically, in the embodiment of the present invention, Figure 6 As shown in , in order to gradually adjust the initial standard vibration load spectrum, set the multiple step size of α to gradually adjust the vibration load spectrum. If there is no crack or crack in the test object after the random vibration test of this cycle, the acceleration power spectrum density value of the vibration load spectrum of the previous cycle is increased by α times, that is, it becomes (1+α) times of the original load spectrum, as shown in Figure 7 As shown, assuming that α is set to 0.1, it is adjusted in sequence as follows: original load spectrum * 1.1, original load spectrum * 1.1 * 1.1, original load spectrum * 1.1 * 1.1 * 1.1, and the adjusted vibration load amplitude is used for random vibration simulation and random vibration test.

[0065] Step S5032: if no cracking occurs, the acceleration power spectrum density value of the preset vibration load spectrum is increased from the first amplitude to the third amplitude according to a preset multiple step size.

[0066] Specifically, in the embodiment of the present invention, Figure 6 As shown in the figure, if the test object has cracks or breaks after the random vibration test of this cycle, the acceleration power spectrum density value of the vibration load spectrum of the previous cycle is reduced by α times, that is, it becomes (1-α) times of the original load spectrum, and the adjusted vibration load amplitude is used for random vibration simulation and random vibration test.

[0067] Step S504, determining whether the cracking results corresponding to the adjacent random vibration tests have changed, and if so, determining the stress threshold according to the simulation results of the corresponding adjacent random vibration simulations.

[0068] Specifically, the above step S504 includes:

[0069] Step S5041, determining whether the cracking results corresponding to adjacent random vibration tests change from cracked to uncracked, or from uncracked to cracked.

[0070] Specifically, in the embodiment of the present invention, if cracks or cracks appear after the random vibration test in the initial cycle, the acceleration power spectrum density value of the preset vibration load spectrum is gradually reduced, and the probability of cracks or cracks appearing after the random vibration test in the subsequent cycles will gradually decrease until no cracks or cracks appear after the random vibration test of a certain cycle, at which time the critical point of cracking is reached. Similarly, the process from no cracks to cracks is similar.

[0071] Step S5042, if a change occurs, obtain a first maximum preset stress in a first random vibration simulation corresponding to a random vibration test in which cracking occurs, and obtain a second maximum preset stress in a second random vibration simulation corresponding to a random vibration test in which cracking does not occur.

[0072] Specifically, in the embodiment of the present invention, the cracking results of the random vibration test in two adjacent cycles may be cracking in the previous cycle and no cracking in the next cycle, or no cracking in the previous cycle and cracking in the next cycle. The random vibration test and the random vibration simulation are performed correspondingly. Therefore, the embodiment of the present invention respectively obtains the maximum 1σ stress σ in the random vibration simulation corresponding to the random vibration test where cracking occurs. 1 , and the maximum 1σ stress σ in the random vibration simulation corresponding to the random vibration test without cracking 2 , σ 1 and σ 2 Corresponding to the critical point of cracking.

[0073] Step S5043, calculating the stress error between the first maximum preset stress and the second maximum preset stress, and if the stress error is less than the preset tolerance threshold, selecting the second maximum preset stress as the stress threshold.

[0074] Specifically, in the embodiment of the present invention, Figure 6 As shown in the figure, in order to ensure the accuracy of the stress threshold, the maximum 1σ stress of two adjacent period random vibration simulations is compared. 1 With σ 2 If the difference is less than the preset tolerance threshold, it is considered that the 1σ stress threshold of the material corresponding to the test object under the vibration time T hours is σ 2 , denoted as σlimit The preset tolerance threshold is set to 5%, which can be set according to actual conditions. This is only an example and is not limited to this. However, if σ 1 With σ 2 If it is greater than 5%, reduce the multiple step size α, for example, reduce it to α / 2, and readjust the vibration load spectrum according to α / 2, and perform the next cycle of random vibration simulation and random vibration test until the difference between the two is less than 5%.

[0075] The method for determining the stress threshold provided in the embodiment of the present invention performs random vibration simulation on the simulation model corresponding to the test object based on the preset vibration load spectrum to determine the maximum preset stress and the corresponding target position, and performs random vibration test on the test object based on the preset vibration load spectrum to determine whether cracking occurs at the target position of the test object. If cracking occurs, the preset vibration load spectrum is adjusted, and the random vibration simulation and random vibration test are repeated until the cracking results corresponding to the adjacent random vibration tests change, and the stress threshold is determined according to the simulation results of the corresponding adjacent random vibration simulations. By performing random vibration tests on the battery pack test object and the corresponding simulation model, the present invention can use a method of gradual approximation of simulation and test to determine the random vibration stress threshold, improve the accuracy of simulation evaluation, avoid large-scale transition design and design deficiencies, and the test object corresponding to the simulation model can be set as a dummy model, and both the simulation model and the dummy model can be reused, thereby reducing the cost of simulation benchmarking.

[0076] In this embodiment, a method for determining the risk of battery pack failure is provided, which can be used in the above-mentioned mobile terminal, such as a computer, etc. Figure 8 is a flow chart of a method for determining the failure risk of a battery pack according to an embodiment of the present invention. Figure 8 As shown, the process includes the following steps:

[0077] Step S801 , performing a random vibration test of a preset duration on the battery pack based on a preset vibration load spectrum, and obtaining a preset stress at any position on the battery pack.

[0078] Specifically, in the embodiment of the present invention, because the stress threshold is obtained by random vibration simulation and random vibration test according to the standard vibration load spectrum and the vibration duration T, when the failure risk of the battery pack is actually judged, the preset vibration time may be different from the vibration duration T due to the influence of the test conditions, etc., so in order to ensure that the stress threshold can be applied to the actual battery pack failure risk judgment, an equivalent conversion is required. Fig. 9As shown, after determining the preset vibration time, the embodiment of the present invention determines whether the preset vibration time is equal to the vibration duration T. If it is equal, a random vibration test of the battery pack with a vibration duration T is performed based on the standard vibration load spectrum. If it is not equal, the acceleration factor is determined according to the battery pack material, and the standard vibration load spectrum is converted into an equivalent vibration load spectrum according to the preset vibration time, vibration duration and acceleration factor. The conversion formula is as follows:

[0079]

[0080] Among them, Apsd' is the acceleration power spectrum density value of the equivalent vibration load spectrum, in units of g2 / Hz; Apsd' is the acceleration power spectrum density value of the preset vibration load spectrum, in units of g2 / Hz; T is the vibration duration T, in units of h; T' is the preset vibration time, in units of h; m is the acceleration coefficient, m = 5 for aluminum alloy materials and m = 4 for steel materials, which is only used as an example and is not limited to this. Then, based on the equivalent vibration load spectrum, a random vibration test is performed on the battery pack with a preset vibration time T', such as Fig.10 As shown in FIG. 1 , the random vibration load curve of 21 hours of vibration duration is converted into the random vibration load curve of 12 hours of vibration duration. After the random vibration test is completed, the 1σ stress at any position on the battery pack is obtained.

[0081] Step S802, obtaining a stress threshold. The stress threshold is based on Figure 1 or Figure 5 The stress threshold is determined by the method for determining the stress threshold shown in the figure, which will not be described in detail here.

[0082] Step S803: Compare the preset stress with the stress threshold to determine whether there is a failure risk at any position.

[0083] Specifically, in the embodiment of the present invention, Fig. 9 As shown, if the 1σ stress at a certain position ≥σ limit , then it is considered that there is a risk of failure at this position. At this time, the battery pack can be optimized structurally or materially. Among them, structural optimization refers to optimizing the structure by adding reinforcing ribs, increasing material thickness, increasing fillet radius, etc., to improve the strength of the battery pack structure; material optimization refers to replacing materials with higher tensile strength, such as changing steel from Q235 to Q460, etc., which is not limited here. If the 1σ stress at a certain position is less than σ limit , then it is considered that there is no failure risk at this position.

[0084] The method for judging the failure risk of a battery pack provided by an embodiment of the present invention performs a random vibration test on the battery pack for a preset time based on a preset vibration load spectrum, compares the preset stress at any position of the battery pack with the stress threshold, and judges whether there is a failure risk at any position. The present invention judges the failure risk of a battery pack based on a predetermined stress threshold, and can accurately judge whether the battery pack has a failure risk, thereby providing an accurate parameter basis for the structural optimization or material optimization of the battery pack, making the battery pack put into use durable and improving the user experience and satisfaction.

[0085] In this embodiment, a device for determining a stress threshold is also provided, and the device is used to implement the above-mentioned embodiments and preferred implementation modes, and the descriptions that have been made will not be repeated. As used below, the term "module" can be a combination of software and / or hardware that implements a predetermined function. Although the device described in the following embodiments is preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceivable.

[0086] This embodiment provides a device for determining a stress threshold, such as Fig.11 As shown, including:

[0087] The first test module 1101 is used to perform random vibration simulation on the simulation model based on a preset vibration load spectrum, and obtain a maximum preset stress and a target position corresponding to the maximum preset stress in the simulation model.

[0088] The second test module 1102 is used to perform a random vibration test of a preset duration on the test object based on a preset vibration load spectrum, and determine whether cracks occur at a target position of the test object, wherein the test object corresponds to the simulation model.

[0089] The cyclic test module 1103 is used to adjust the preset vibration load spectrum according to the cracking result, and perform random vibration simulation on the simulation model in sequence based on the adjusted vibration load spectrum, and perform random vibration test on the test object.

[0090] The threshold determination module 1104 is used to determine whether the cracking results corresponding to adjacent random vibration tests have changed. If so, the stress threshold is determined according to the simulation results of the corresponding adjacent random vibration simulations.

[0091] In some optional embodiments, the cycle test module 1103 includes:

[0092] The first amplitude adjustment unit is used to reduce the acceleration power spectrum density value of the preset vibration load spectrum from the first amplitude to the second amplitude according to a preset multiple step if cracking occurs.

[0093] The second amplitude adjustment unit is used to increase the acceleration power spectrum density value of the preset vibration load spectrum from the first amplitude to the third amplitude according to a preset multiple step if no cracking occurs.

[0094] In some optional implementations, the threshold determination module 1104 includes:

[0095] The cracking result judgment unit is used to judge whether the cracking results corresponding to adjacent random vibration tests change from cracking to non-cracked, or from non-cracked to cracked.

[0096] The stress acquisition unit is used to acquire a first maximum preset stress in a first random vibration simulation corresponding to a random vibration test in which cracking occurs, and to acquire a second maximum preset stress in a second random vibration simulation corresponding to a random vibration test in which cracking does not occur, if a change occurs.

[0097] The stress threshold determination unit is used to calculate the stress error between the first maximum preset stress and the second maximum preset stress, and if the stress error is less than the preset tolerance threshold, the second maximum preset stress is selected as the stress threshold.

[0098] In some optional implementations, the threshold determination module 1104 further includes:

[0099] The step adjustment unit is used to reduce the preset multiple step if the stress error is not less than the preset tolerance threshold, and return to the step of adjusting the preset vibration load spectrum according to the cracking result, and based on the adjusted vibration load spectrum, sequentially perform random vibration simulation on the simulation model and perform random vibration test on the test object.

[0100] The further functional description of each of the above modules and units is the same as that of the above corresponding embodiments and will not be repeated here.

[0101] The stress threshold determination device in this embodiment is presented in the form of a functional unit, where the unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and memory that executes one or more software or fixed programs, and / or other devices that can provide the above functions.

[0102] This embodiment provides a device for determining the risk of battery pack failure. Fig.12 As shown, including:

[0103] The third test module 1201 is used to perform a random vibration test of a preset duration on the battery pack based on a preset vibration load spectrum, and obtain a preset stress at any position on the battery pack.

[0104] The threshold acquisition module 1202 is used to acquire the stress threshold. The stress threshold is based on the above Figure 1 or Figure 5 The random vibration simulation stress threshold is determined by the method shown.

[0105] The risk judgment module 1203 is used to compare the preset stress with the stress threshold to determine whether there is a failure risk at any position.

[0106] In some optional embodiments, the device also includes: an equivalent conversion module, used to determine a preset vibration time, and determine whether the preset vibration time is equal to a preset duration; if not, determine a preset acceleration coefficient, and convert the preset vibration load spectrum into an equivalent vibration load spectrum according to the preset vibration time, preset duration and preset acceleration coefficient; based on the equivalent vibration load spectrum, perform a random vibration test on the battery pack for a preset vibration time.

[0107] The further functional description of each of the above modules and units is the same as that of the above corresponding embodiments and will not be repeated here.

[0108] The battery pack failure risk judgment device in this embodiment is presented in the form of a functional unit, where the unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and memory that executes one or more software or fixed programs, and / or other devices that can provide the above functions.

[0109] The embodiment of the present invention also provides a computer device having the above Fig.11 means for determining the stress threshold as shown, or Fig.12 The device for determining the risk of battery pack failure is shown.

[0110] See also Fig.13 , Fig.13 is a schematic diagram of the structure of a computer device provided by an optional embodiment of the present invention, such as Fig.13 As shown, the computer device includes: one or more processors 10, a memory 20, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. Various components are connected to each other using different buses for communication, and can be installed on a common mainboard or installed in other ways as needed. The processor can process the instructions executed in the computer device, including instructions stored in or on the memory to display the graphical information of the GUI on an external input / output device (such as, a display device coupled to the interface). In some optional embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Similarly, multiple computer devices can be connected, and each device provides some necessary operations (for example, as a server array, a group of blade servers, or a multi-processor system). Fig.13A processor 10 is taken as an example.

[0111] The processor 10 may be a central processing unit, a network processor or a combination thereof. The processor 10 may further include a hardware chip. The hardware chip may be a dedicated integrated circuit, a programmable logic device or a combination thereof. The programmable logic device may be a complex programmable logic device, a field programmable gate array, a general purpose array logic or any combination thereof.

[0112] The memory 20 stores instructions executable by at least one processor 10, so that the at least one processor 10 executes the method shown in the above embodiment.

[0113] The memory 20 may include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function; the data storage area may store data created according to the use of the computer device, etc. In addition, the memory 20 may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some optional embodiments, the memory 20 may optionally include a memory remotely arranged relative to the processor 10, and these remote memories may be connected to the computer device via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0114] The memory 20 may include a volatile memory, such as a random access memory; the memory may also include a non-volatile memory, such as a flash memory, a hard disk or a solid state drive; the memory 20 may also include a combination of the above types of memory.

[0115] The computer device also includes an input device 30 and an output device 40. The processor 10, the memory 20, the input device 30 and the output device 40 may be connected via a bus or other means. Fig.13 The example of connecting through bus is taken in the following.

[0116] The input device 30 can receive input digital or character information, and generate key signal input related to the user settings and function control of the computer device, such as a touch screen, a keypad, a mouse, a track pad, a touch pad, an indicator bar, one or more mouse buttons, a trackball, a joystick, etc. The output device 40 may include a display device, an auxiliary lighting device (e.g., an LED) and a tactile feedback device (e.g., a vibration motor), etc. The above-mentioned display device includes but is not limited to a liquid crystal display, a light emitting diode, a display and a plasma display. In some optional embodiments, the display device can be a touch screen.

[0117] The embodiment of the present invention also provides a computer-readable storage medium. The method according to the embodiment of the present invention can be implemented in hardware, firmware, or can be implemented as a computer code that can be recorded in a storage medium, or can be implemented as a computer code that is originally stored in a remote storage medium or a non-temporary machine-readable storage medium and will be stored in a local storage medium through a network download, so that the method described herein can be stored in such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only storage memory, a random access memory, a flash memory, a hard disk or a solid-state hard disk, etc.; further, the storage medium can also include a combination of the above types of memories. It can be understood that a computer, a processor, a microprocessor controller, or programmable hardware includes a storage component that can store or receive software or computer code. When the software or computer code is accessed and executed by a computer, a processor, or hardware, the method shown in the above embodiment is implemented.

[0118] A part of the present invention may be applied as a computer program product, such as a computer program instruction, which, when executed by a computer, can call or provide the method and / or technical solution according to the present invention through the operation of the computer. Those skilled in the art should understand that the existence of the computer program instruction in a computer-readable medium includes, but is not limited to, a source file, an executable file, an installation package file, etc., and accordingly, the way in which the computer program instruction is executed by the computer includes, but is not limited to: the computer directly executes the instruction, or the computer compiles the instruction and then executes the corresponding compiled program, or the computer reads and executes the instruction, or the computer reads and installs the instruction and then executes the corresponding installed program. Here, the computer-readable medium may be any available computer-readable storage medium or communication medium accessible to the computer.

[0119] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A method for determining a stress threshold, characterized in that: The method comprises: Performing random vibration simulation on the simulation model based on a preset vibration load spectrum, and obtaining a maximum preset stress and a target position in the simulation model corresponding to the maximum preset stress; Based on the preset vibration load spectrum, a random vibration test of a preset duration is performed on the test object, and it is determined whether cracks occur at the target position of the test object, wherein the test object corresponds to the simulation model; The preset vibration load spectrum is adjusted according to the cracking result, and random vibration simulation is performed on the simulation model in sequence based on the adjusted vibration load spectrum, and random vibration test is performed on the test object; It is determined whether the cracking results corresponding to the adjacent random vibration tests have changed. If changed, a stress threshold is determined according to the simulation results of the corresponding adjacent random vibration simulations.

2. The method according to claim 1, characterized in that The adjusting the preset vibration load spectrum according to the cracking result includes: If cracking occurs, reducing the acceleration power spectrum density value of the preset vibration load spectrum from the first amplitude to the second amplitude according to a preset multiple step size; If no cracking occurs, the acceleration power spectrum density value of the preset vibration load spectrum is increased from the first amplitude to the third amplitude according to the preset multiple step size.

3. The method according to claim 2, characterized in that The determining whether the cracking result corresponding to the adjacent random vibration test has changed, and if so, determining the stress threshold according to the simulation result of the corresponding adjacent random vibration simulation, comprises: Determine whether the cracking result corresponding to the adjacent random vibration test changes from cracked to uncracked, or from uncracked to cracked; If a change occurs, a first maximum preset stress in a first random vibration simulation corresponding to a random vibration test in which cracking occurs is obtained, and a second maximum preset stress in a second random vibration simulation corresponding to a random vibration test in which cracking does not occur is obtained; A stress error between the first maximum preset stress and the second maximum preset stress is calculated, and if the stress error is less than a preset tolerance threshold, the second maximum preset stress is selected as the stress threshold.

4. The method according to claim 3, characterized in that After calculating the stress error between the first maximum preset stress and the second maximum preset stress, the method further includes: If the stress error is not less than the preset tolerance threshold, the preset multiple step size is reduced, and the method returns to the step of adjusting the preset vibration load spectrum according to the cracking result, and performing random vibration simulation on the simulation model in turn based on the adjusted vibration load spectrum, and performing random vibration test on the test object.

5. A method for determining the risk of battery pack failure, characterized in that: The method comprises: Performing a random vibration test on the battery pack for a preset time based on a preset vibration load spectrum, and obtaining a preset stress at any position on the battery pack; Acquire a stress threshold, where the stress threshold is determined according to the method for determining a stress threshold according to any one of claims 1 to 4; The preset stress is compared with the stress threshold to determine whether there is a failure risk at any position.

6. The method according to claim 5, characterized in that The random vibration test of the battery pack for a preset time based on the preset vibration load spectrum includes: Determining a preset vibration time, and judging whether the preset vibration time is equal to the preset duration; If not equal, determining a preset acceleration coefficient, and converting the preset vibration load spectrum into an equivalent vibration load spectrum according to the preset vibration time, the preset duration and the preset acceleration coefficient; A random vibration test is performed on the battery pack for a preset vibration time based on the equivalent vibration load spectrum.

7. A device for determining a stress threshold, characterized in that: The device comprises: A first test module is used to perform random vibration simulation on the simulation model based on a preset vibration load spectrum, and obtain a maximum preset stress and a target position in the simulation model corresponding to the maximum preset stress; A second test module is used to perform a random vibration test of a preset duration on the test object based on the preset vibration load spectrum, and determine whether cracks occur at the target position of the test object, wherein the test object corresponds to the simulation model; A cyclic test module, used for adjusting the preset vibration load spectrum according to the cracking result, and performing random vibration simulation on the simulation model in sequence based on the adjusted vibration load spectrum, and performing random vibration test on the test object; The threshold determination module is used to determine whether the cracking results corresponding to the adjacent random vibration tests have changed. If changed, the stress threshold is determined according to the simulation results of the corresponding adjacent random vibration simulations.

8. A device for determining the risk of battery pack failure, characterized in that: The device comprises: A third test module is used to perform a random vibration test of a preset duration on the battery pack based on a preset vibration load spectrum, and obtain a preset stress at any position on the battery pack; A threshold acquisition module, used to acquire a stress threshold, wherein the stress threshold is determined according to the method for determining a random vibration simulation stress threshold according to any one of claims 1 to 4; The risk judgment module is used to compare the preset stress with the stress threshold to judge whether there is a failure risk at any position.

9. A computer device, characterized in that: include: A memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the method for determining the stress threshold value according to any one of claims 1 to 4, or the method for determining the failure risk of a battery pack according to any one of claims 5 to 6 by executing the computer instructions.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, which are used to enable a computer to execute the method for determining the stress threshold value described in any one of claims 1 to 4, or to execute the method for determining the failure risk of a battery pack described in any one of claims 5 to 6.

11. A computer program product, characterized in that The method comprises computer instructions, wherein the computer instructions are used to cause a computer to execute the method for determining the stress threshold value according to any one of claims 1 to 4, or to execute the method for determining the failure risk of a battery pack according to any one of claims 5 to 6.

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