A 48-voltage pulse-based power battery thermal runaway detection method and device

Abstract

The application discloses a kind of power battery thermal runaway detection method and device based on 48V voltage pulse, comprising: obtaining by vehicle-mounted 48V low-voltage battery as excitation source, short pulse is applied to the high-voltage power battery pack to be measured by switch array;Real-time acquisition voltage signal, current signal and temperature signal of the high-voltage power battery pack in the process of applying short pulse;Based on voltage signal, current signal and temperature signal in the process of short pulse, the primary heat-sensitive factor is calculated;When the primary sensitive factor system is less than or equal to the first preset threshold, continue the above steps, otherwise, enter next step process;Obtain by vehicle-mounted 48V low-voltage battery as excitation source.Main technical scheme and effect: the application can issue thermal runaway early warning 15 minutes in advance or earlier by analyzing the internal resistance mutation of battery under low-voltage voltage pulse excitation, compared with prior art, significantly advance early warning time.

Description

Technical Field

[0001] This invention relates to the field of battery thermal runaway early warning, and in particular to a method and device for detecting thermal runaway of power batteries based on a 48V voltage pulse. Background Technology

[0002] With the rapid development of the new energy vehicle industry, the safety issues of power batteries, especially lithium-ion batteries, are becoming increasingly prominent. Battery thermal runaway is the most serious form of battery failure, which can cause smoke, fire, or even explosion in a very short time, posing a huge threat to the lives and property of passengers. Therefore, developing thermal runaway detection technology that can provide early and accurate warnings is of paramount importance for improving the safety level of electric vehicles.

[0003] Currently, the industry mainly relies on the following technical solutions for the detection and early warning of thermal runaway in power batteries:

[0004] Temperature monitoring method: This method uses an array of temperature sensors placed inside or on the surface of the battery pack to monitor the battery temperature and its rate of change in real time. When the temperature exceeds a preset threshold or the rate of temperature rise is abnormal, it is determined to be at risk of thermal runaway. However, there is a significant thermal hysteresis in the transfer of heat generated inside the battery to the surface sensors, resulting in a long response delay for this method. It often only alerts the user when thermal runaway has already entered a severe stage, missing the golden window for early intervention.

[0005] Gas detection method: This method monitors characteristic gases released during the initial stage of battery thermal runaway (such as CO, etc.). This method uses the concentration of certain gases (such as...) to provide early warnings. While it can signal an alarm to some extent before a significant temperature rise, the generation, accumulation, and diffusion of these characteristic gases are greatly affected by factors such as battery packaging and environmental ventilation, easily leading to false alarms or missed alarms. Existing technology shows that the false alarm rate of such methods is typically higher than 15%, and their reliability is insufficient to meet the requirements of automotive-grade applications.

[0006] AC impedance method: This method calculates the battery's internal impedance spectrum by injecting a small AC signal of a specific frequency into the battery and measuring its voltage and current response. Changes in the impedance spectrum are then used to diagnose the battery's internal state. Theoretically, this method can sensitively reflect minute changes in the battery's internal electrochemical state. However, this method typically requires dedicated high-precision signal generators and analysis equipment, resulting in a complex, costly system with significant power consumption and size. This makes it difficult to integrate into an onboard battery management system (BMS) for real-time, online monitoring, and it suffers from poor portability and applicability. Summary of the Invention

[0007] Purpose of the invention: The purpose of this invention is to solve the technical problems in the prior art and provide a method and device for detecting thermal runaway of power batteries based on 48V voltage pulse.

[0008] This specification relates to one or more embodiments of a power battery thermal runaway detection device based on a 48V voltage pulse, an electronic device, a computer-readable storage medium, and a computer program product, in order to solve the technical defects existing in the prior art.

[0009] Technical solution:

[0010] Firstly, this application proposes a method for detecting thermal runaway of a power battery based on a 48V voltage pulse, comprising:

[0011] S101. Using the vehicle's 48V low-voltage battery as an excitation source, apply a short pulse to the high-voltage power battery pack under test through a switch array.

[0012] S102. Real-time acquisition of voltage, current and temperature signals of the high-voltage power battery pack during the application of short pulses;

[0013] S103. The primary thermal sensitivity factor is calculated based on the voltage, current and temperature signals during the short pulse process.

[0014] S104. If the primary sensitive factor is less than or equal to the first preset threshold, continue the above steps; otherwise, proceed to the next step.

[0015] S105. Using the vehicle's 48V low-voltage battery as the excitation source, apply medium and high pulses to the high-voltage power battery pack under test through a switch array.

[0016] S106. Real-time acquisition of voltage, current and temperature signals of the high-voltage power battery pack during the application of medium and high pulses;

[0017] S107. The complete thermal sensitivity factor is calculated based on the voltage, current and temperature signals during medium and high pulse processes.

[0018] S108. If the complete thermal sensitivity factor is greater than the second preset threshold, disconnect the high-voltage power battery pack relay; otherwise, record the detection and calculation data and return to step S101.

[0019] Preferably, the short pulse width is 10ms, which is used to capture sudden changes in ohmic internal resistance;

[0020] The pulse width of the medium pulse is 1 second, used to monitor changes in polarization impedance;

[0021] The long pulse has a pulse width of 10s and is used to analyze the diffusion time constant.

[0022] Preferably, the switch array is a MOSFET switch array with a switching frequency of 100kHz.

[0023] Preferably, the voltage, current, and temperature signals of the high-voltage power battery pack are acquired in real time during the application of a short pulse, including:

[0024] Under short pulse conditions, the open-circuit voltage of the high-voltage power battery before the pulse, the minimum voltage after the pulse, the peak current, and the high-voltage battery pack temperature after the pulse are collected respectively, and the preset temperature compensation coefficient of the corresponding battery pack is obtained.

[0025] Preferably, the primary thermal sensitivity factor is calculated based on the voltage, current, and temperature signals during the short pulse process, including:

[0026] Based on the acquired signal, the change in ohmic internal resistance ΔR based on the short-pulse response is calculated. Ω ,

[0027] Based on ΔR Ω and reference ohmic internal resistance R Ω0 The primary heat sensitivity factor was calculated.

[0028] The formula is as follows:

[0029] .

[0030] Preferably, the change in ohmic internal resistance ΔR based on the short-pulse response Ω The calculation steps are as follows:

[0031] The formula for calculating polarization resistance is as follows:

[0032] ;

[0033] Among them, V ocv The open-circuit voltage of the high-voltage power battery before the pulse, V min The lowest voltage value after the pulse, I peak K represents the peak current, T represents the high-voltage battery pack temperature after the pulse, and K represents the voltage level. T The preset temperature compensation coefficient for the battery pack;

[0034] The formula for calculating the change in ohmic internal resistance is as follows:

[0035] .

[0036] The calculation of the thermal sensitivity factor (TSF) can help assess the risk of thermal runaway in a battery in real time. This is achieved by monitoring changes in ohmic internal resistance (ΔR). Ω This can predict whether a battery is at risk of thermal runaway.

[0037] The calculation of ohmic internal resistance takes into account the effect of battery temperature. The higher the temperature, the higher the battery internal resistance usually is. Therefore, a temperature compensation coefficient k is included. TThis is to correct the impact of temperature on battery performance.

[0038] These formulas allow the system to monitor the battery's health status in real time under different temperature and current conditions, and promptly identify potential problems.

[0039] Preferably, the voltage, current, and temperature signals of the high-voltage power battery pack are acquired in real time during the application of the pulse, including:

[0040] Under medium-pulse conditions, the following data were collected: the time at the start of the high-voltage power battery, the time at the end of the pulse, the voltage at time t during the voltage recovery period after the pulse ends, the open-circuit voltage of the high-voltage power battery before the pulse, and the current value of the high-voltage power battery at time t.

[0041] Preferably, the voltage, current, and temperature signals of the high-voltage power battery pack are acquired in real time during the application of a high pulse, including:

[0042] Under long pulse conditions, the steady-state recovery voltage, instantaneous voltage at the end of the pulse, and steady-state voltage during the voltage recovery period after the pulse end of the high-voltage power battery at time t after the pulse ends were collected.

[0043] Preferably, the complete thermal sensitivity factor is calculated based on the voltage, current and temperature signals during the medium and high pulse processes;

[0044] The polarization impedance change based on the mid-pulse response was calculated;

[0045] The diffusion time constant was calculated.

[0046] The complete thermal sensitivity factor is calculated based on the polarization impedance change and diffusion time constant.

[0047] Preferably, based on the acquired signal, the polarization impedance change based on the mid-pulse response is calculated, including the following steps:

[0048] The polarization impedance is calculated using the following formula:

[0049] ;

[0050] Where t0 is the time at the start of the pulse, t1 is the time at the end of the pulse, V(t) is the voltage at time t during the voltage recovery period after the pulse ends, and V... OCV The open-circuit voltage of the high-voltage power battery before the pulse, and the current value of the high-voltage power battery at time t (I(t)).

[0051] The formula for calculating the change in polarization impedance is as follows:

[0052] ;

[0053] Among them, Rp0 The reference ohmic impedance is used.

[0054] Calculations of polarization impedance and diffusion time constant help analyze the electrochemical reaction process of the battery and determine whether the battery is in normal working condition.

[0055] ΔR p and τ d These are important indicators of battery health, especially when the battery is aging or malfunctioning. Changes in these parameters can provide early warnings of potential battery problems, such as separator damage or overheating.

[0056] Preferably, the diffusion time constant is calculated using the following formula:

[0057] ;

[0058] Where V(t) represents the steady-state recovery voltage of the high-voltage power battery at time t after the end of the pulse under long pulse conditions, V1 represents the instantaneous voltage at the end of the pulse, and V 0为 The steady-state voltage during the voltage recovery period after the pulse ends.

[0059] Preferably, the complete thermal sensitivity factor is calculated based on the change in polarization impedance and the diffusion time constant, including:

[0060] ;

[0061] Where α and β are weighting coefficients.

[0062] Secondly, embodiments of the present invention provide a power battery thermal runaway detection device based on a 48V voltage pulse, comprising:

[0063] The acquisition unit is used to acquire short pulses, medium pulses, and high pulses applied to the high-voltage power battery pack under test by the vehicle's 48V low-voltage battery as the excitation source through a switch array;

[0064] The acquisition unit is used to acquire voltage, current and temperature signals of the high-voltage power battery pack in real time during the application of short pulses, medium pulses and high pulses;

[0065] The calculation unit is used to calculate the primary thermal sensitivity factor and the complete thermal sensitivity factor based on the voltage signal, current signal and temperature signal during short pulse, medium pulse and high pulse processes;

[0066] The judgment unit is used to determine that if the primary sensitive factor is less than or equal to the first preset threshold, the above steps continue to be repeated; if the complete thermal sensitive factor is greater than the second preset threshold, the high-voltage power battery pack relay is disconnected.

[0067] Thirdly, embodiments of the present invention provide an electronic device, including a processor and a memory. The memory stores one or more computer programs; when the one or more computer programs stored in the memory are executed by the processor, the electronic device is able to implement any of the possible design methods described in the first aspect.

[0068] Fourthly, the present invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the method as described in any of the above embodiments.

[0069] Fifthly, embodiments of the present invention also provide a computer program product that, when run on an electronic device, causes the electronic device to perform any possible design method of any of the above aspects.

[0070] Beneficial effects:

[0071] This invention analyzes the sudden change in internal resistance of a battery under low-voltage pulse excitation, enabling it to issue a thermal runaway warning 15 minutes or more in advance. Compared to existing technologies (temperature monitoring and gas detection methods typically lag by 3-5 minutes), this significantly improves the warning time. This allows the driver and passengers to evacuate in time and triggers the vehicle's active safety measures (such as power reduction and disconnection of high-voltage power), greatly reducing the risk of personal injury and vehicle damage caused by battery thermal runaway.

[0072] The dynamic temperature-SOC compensation algorithm and adaptive thermal sensitivity factor (TSF) model employed in this invention can effectively address the challenges of extremely cold (-40°C) and high (85°C) environments, and reduce false alarms caused by factors such as temperature drift or charging polarization. The false alarm rate is reduced to below 1.2%, compared to more than 15% for traditional solutions, significantly improving the reliability of the detection results.

[0073] This invention innovatively uses the vehicle's existing 48V low-voltage battery as the detection excitation source, completely eliminating the need for costly and difficult-to-integrate dedicated signal generators, thereby reducing the system's hardware cost by over 90%. Simultaneously, due to its compact design and low power consumption, it can be directly and seamlessly integrated into existing battery management systems (BMS) or electronic control units (ECUs). This solution enables the widespread adoption of advanced safety features in a range of electric vehicles, from luxury to economy models, significantly accelerating the commercialization of this technology. Attached Figure Description

[0074] Figure 1 A schematic diagram of the method framework for this invention is provided;

[0075] Figure 2 A flowchart is provided for this invention;

[0076] Figure 3 This is a block diagram of a device structure provided in one embodiment of this application;

[0077] Figure 4 This is a block diagram of an electronic device structure provided in one embodiment of this application. Detailed Implementation

[0078] To make the technical solution of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0079] Example 1

[0080] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art. The terms "comprising" and similar expressions used herein mean that the element or object preceding the word covers the element or object listed following the word and its equivalents, but do not exclude other elements or objects.

[0081] In response to the problems existing in the current technology, such as Figure 1 As shown, a method for detecting thermal runaway of a power battery based on a 48V voltage pulse is proposed, including:

[0082] S101. Using the vehicle's 48V low-voltage battery as an excitation source, apply a short pulse to the high-voltage power battery pack under test through a switch array.

[0083] S102. Real-time acquisition of voltage, current and temperature signals of the high-voltage power battery pack during the application of short pulses;

[0084] Real-time acquisition of voltage signals: When a short pulse (e.g., 10ms) is applied, the voltage change of the battery pack reflects the physical and chemical reactions inside the battery, such as the decomposition of the SEI film. The voltage signal is acquired through a 24-bit ADC (analog-to-digital converter) with a sampling rate of 10kHz, ensuring accurate capture of minute voltage changes (e.g., microvolt-level voltage changes).

[0085] Real-time current signal acquisition: The battery current change is monitored in real time using a closed-loop Hall sensor. This sensor has a range of ±100A and a zero-point error of less than 0.1% FS, ensuring high-precision current acquisition.

[0086] Real-time acquisition of temperature signals: Changes in the internal temperature of the battery are crucial for early warning of thermal runaway. Using a PT1000 array temperature sensor, the system can monitor temperature changes on the battery surface in real time with an accuracy of ±0.1°C.

[0087] S103. The primary thermal sensitivity factor is calculated based on the voltage, current and temperature signals during the short pulse process.

[0088] S104. If the primary sensitive factor is less than or equal to the first preset threshold, continue the above steps; otherwise, proceed to the next step.

[0089] In some specific embodiments, a short pulse with a pulse width of 10 ms is used to capture sudden changes in ohmic internal resistance; a pulse with a pulse width of 10 milliseconds is primarily used to capture sudden changes in ohmic internal resistance. This short pulse helps detect rapid changes in ohmic internal resistance caused by factors such as electrolyte decomposition or SEI film rupture in the early stages of thermal runaway. Stimulation with a short pulse allows for real-time monitoring of changes in internal resistance, thereby enabling early detection of battery anomalies.

[0090] The medium-length pulse has a pulse width of 1 second and is used to monitor changes in polarization impedance; the 1-second pulse is primarily used to monitor changes in polarization impedance. During battery charging and discharging, changes in polarization impedance are related to the acceleration of electrochemical reactions. The 1-second pulse duration can effectively capture the battery's reactions under these conditions, promptly detecting abnormalities in the battery's internal reactions, especially when some early chemical changes occur within the battery.

[0091] The long pulse, with a pulse width of 10 seconds, is used to analyze the diffusion time constant. The diffusion time constant reflects the rate of ion diffusion within the battery. By applying a long pulse, the recovery process of the battery voltage over a long period can be observed, helping to analyze whether the battery separator is damaged or whether there are internal short circuits. Changes in diffusion impedance are crucial for determining the battery's health condition, especially under conditions of battery aging and overheating.

[0092] In some specific embodiments, the switch array is a MOSFET switch array with a switching frequency of 100kHz. The MOSFET switch array is a core component of this system, used for precise control of voltage pulse application, especially for pulse excitation of high-voltage battery packs. It can precisely adjust the pulse width and frequency, enabling the system to flexibly generate voltage pulses of different time scales (such as short pulses, medium pulses, and long pulses). Because MOSFETs are used as switching components, these switches can operate at very high frequencies, ensuring a fast and accurate response to pulse signals.

[0093] A switching frequency of 100kHz means the MOSFET array can switch 100,000 times per second, generating precise voltage pulses in an extremely short time. This high-frequency switching allows the system to precisely control the application of voltage pulses at the millisecond level and to capture minute changes in battery internal resistance and other characteristics in real time.

[0094] In some specific embodiments, the voltage, current, and temperature signals of the high-voltage power battery pack are acquired in real time during the application of a short pulse, including:

[0095] Under short pulse conditions, the open-circuit voltage of the high-voltage power battery before the pulse, the minimum voltage after the pulse, the peak current, and the high-voltage battery pack temperature after the pulse are collected respectively, and the preset temperature compensation coefficient of the corresponding battery pack is obtained.

[0096] In some specific embodiments, the dynamic current limiting protection circuit (IGBT + 0.5Ω power resistor) ensures that the peak current Imax = min(5%C, 50A) (C is the high voltage transformer capacity) to prevent overcurrent damage.

[0097] In some specific embodiments, a primary thermal sensitivity factor is calculated based on voltage, current, and temperature signals during a short pulse process, including:

[0098] Based on the acquired signal, the change in ohmic internal resistance ΔR based on the short-pulse response is calculated. Ω ,

[0099] Based on ΔR Ω and reference ohmic internal resistance R Ω0 The primary heat sensitivity factor was calculated.

[0100] The formula is as follows:

[0101] .

[0102] In some specific embodiments, the change in ohmic internal resistance ΔR based on the short impulse response Ω The calculation steps are as follows:

[0103] The formula for calculating polarization resistance is as follows:

[0104] ;

[0105] Among them, V ocv The open-circuit voltage of the high-voltage power battery before the pulse, V min The lowest voltage value after the pulse, I peak K represents the peak current, T represents the high-voltage battery pack temperature after the pulse, and K represents the voltage level. T The preset temperature compensation coefficient for the battery pack; for lithium iron phosphate, it is 0.008 / ℃.

[0106] The formula for calculating the change in ohmic internal resistance is as follows:

[0107] .

[0108] S105. Using the vehicle's 48V low-voltage battery as the excitation source, apply medium and high pulses to the high-voltage power battery pack under test through a switch array.

[0109] S106. Real-time acquisition of voltage, current and temperature signals of the high-voltage power battery pack during the application of medium and high pulses;

[0110] S107. The complete thermal sensitivity factor is calculated based on the voltage, current and temperature signals during medium and high pulse processes.

[0111] S108. If the complete thermal sensitivity factor is greater than the second preset threshold, disconnect the high-voltage power battery pack relay; otherwise, record the detection and calculation data and return to step S101.

[0112] In some specific embodiments, the first preset threshold can be set to 0.8 and the second preset threshold can be set to 1.5.

[0113] In some specific embodiments, the voltage, current, and temperature signals of the high-voltage power battery pack are acquired in real time during the application of a pulse, including:

[0114] Under medium-pulse conditions, the following data were collected: the time at the start of the high-voltage power battery, the time at the end of the pulse, the voltage at time t during the voltage recovery period after the pulse ends, the open-circuit voltage of the high-voltage power battery before the pulse, and the current value of the high-voltage power battery at time t.

[0115] In some specific embodiments, the voltage, current, and temperature signals of the high-voltage power battery pack are acquired in real time during the application of a high pulse, including:

[0116] Under long pulse conditions, the steady-state recovery voltage, instantaneous voltage at the end of the pulse, and steady-state voltage during the voltage recovery period after the pulse end of the high-voltage power battery at time t after the pulse ends were collected.

[0117] In some specific embodiments, the complete thermal sensitivity factor is calculated based on the voltage, current and temperature signals during the medium and high pulse processes;

[0118] The polarization impedance change based on the mid-pulse response was calculated;

[0119] The diffusion time constant was calculated.

[0120] The complete thermal sensitivity factor is calculated based on the polarization impedance change and diffusion time constant.

[0121] In some specific embodiments, the polarization impedance change based on the acquired signal is calculated, including the following steps:

[0122] The polarization impedance is calculated using the following formula:

[0123] ;

[0124] Where t0 is the time at the start of the pulse, t1 is the time at the end of the pulse, V(t) is the voltage at time t during the voltage recovery period after the pulse ends, and V... OCV The open-circuit voltage of the high-voltage power battery before the pulse, and the current value of the high-voltage power battery at time t (I(t)).

[0125] The formula for calculating the change in polarization impedance is as follows:

[0126] ;

[0127] Among them, R p0 The reference ohmic impedance is used.

[0128] In some specific embodiments, the diffusion time constant is calculated using the following formula:

[0129] ;

[0130] Wherein, V(t) is the steady-state recovery voltage of the high-voltage power battery at time t after the end of the pulse under long pulse conditions, V1 is the instantaneous voltage at the end of the pulse, and V0 is the steady-state voltage during the voltage recovery period after the end of the pulse.

[0131] During pulse excitation, the electrolyte and electrode materials of a battery may undergo polarization, leading to an uneven distribution of ion concentration within the battery. This unevenness typically causes voltage instability.

[0132] After the pulse ends, the ion concentration inside the battery begins to diffuse and gradually returns to an equilibrium state. This process is a typical dynamic relaxation process; the non-uniformity of ion concentration gradually disappears over time, and the battery voltage gradually recovers.

[0133] The relationship between voltage recovery and ion diffusion rate: The voltage recovery rate of a battery after a pulse ends directly reflects the diffusion rate of ions inside the battery. The speed of voltage recovery indicates the process by which ions inside the battery transition from a polarized state to an equilibrium state.

[0134] If the voltage recovers quickly, it indicates that ion diffusion is relatively smooth and the battery is in good condition.

[0135] If the voltage recovers slowly, it indicates that ion diffusion is difficult, which may indicate that the battery separator is damaged or the battery is aging. In this case, the battery may have performance degradation or failure risk.

[0136] V(t) represents the battery voltage measured at different time points t after the pulse ends (i.e., after time t>10s). By recording this series of voltage data (i.e., the voltage changes over time), the battery's voltage recovery process can be understood.

[0137] These data points were used to fit and calculate the diffusion time constant τ d This is the characteristic time of the ion diffusion process. This constant reflects the ease or difficulty of ion diffusion within the battery.

[0138] τ d The meaning of τ d It is a key parameter in the battery recovery process. It represents the time characteristics of ion diffusion inside the battery. Specifically: if τ d A larger value indicates slower ion diffusion and a longer battery recovery process. This is usually due to damage to the battery separator or other internal problems, which hinder ion diffusion and thus affect battery performance and safety.

[0139] If τ d A smaller value indicates faster ion diffusion, better battery recovery ability, and generally indicates that the battery is in a healthy state.

[0140] In some specific embodiments, the complete thermal sensitivity factor is calculated based on the polarization impedance change and the diffusion time constant, including:

[0141] ;

[0142] Where α and β are weighting coefficients. A dynamic weighting mechanism (α=0.7 at high temperatures, β=0.4 at high SOC) improves robustness across all operating conditions. The baseline values ​​are α=0.6, β=0.3, γ is the diffusion impedance weight, which is constant (diaphragm damage is the ultimate indicator), with a baseline value of 0.1, t c R is the time decay constant, with a reference value of 3s. Ω0 The data was obtained by fitting historical data. It was updated every 100 cycles to exclude the effects of aging.

[0143] The thermal sensitivity factor (TSF) is determined by comprehensively considering ohmic resistance, polarization impedance, and diffusion time constant. fullIt provides a comprehensive assessment of battery health and thermal runaway risk. Under different operating conditions, the battery's health status (such as ion diffusion capacity, electrochemical reaction rate, etc.) will affect these parameters, thus affecting the final thermal sensitivity factor. By monitoring and calculating these parameters in real time, the system can provide early warning of potential thermal runaway and trigger safety protection measures.

[0144] In other embodiments of the present invention, a power battery thermal runaway detection device based on a 48V voltage pulse is disclosed, comprising:

[0145] Acquisition unit 201 is used to acquire short pulses, medium pulses and high pulses applied to the high-voltage power battery pack under test by a switch array using the vehicle-mounted 48V low-voltage battery as the excitation source.

[0146] The acquisition unit 202 is used to acquire in real time the voltage signal, current signal and temperature signal of the high-voltage power battery pack during the application of short pulse, medium pulse and high pulse;

[0147] The calculation unit 203 is used to calculate the primary thermal sensitivity factor and the complete thermal sensitivity factor based on the voltage signal, current signal and temperature signal during the short pulse, medium pulse and high pulse process.

[0148] The judgment unit 204 is used to continue the above steps when the primary sensitive factor is less than or equal to the first preset threshold; and to disconnect the high-voltage power battery pack relay when the complete thermal sensitive factor is greater than the second preset threshold.

[0149] All relevant content of each step involved in the above method embodiments can be referenced from the functional description of the corresponding functional module, and will not be repeated here.

[0150] In other embodiments of the present invention, an electronic device 400 is disclosed, such as... Figure 4 As shown, the electronic device may include: one or more processors 401; a memory 402; a display 403; one or more application programs (not shown); and one or more computer programs 404. These devices can be connected via one or more communication buses 405. The one or more computer programs 404 are stored in the memory 402 and configured to be executed by the one or more processors 401. The one or more computer programs 404 include instructions that can be used to perform actions such as... Figures 1 to 2 And the steps in the corresponding embodiments.

[0151] Through the above description of the embodiments, those skilled in the art will clearly understand that, for the sake of convenience and brevity, only the division of the above functional modules is used as an example. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. The specific working process of the system, device, and unit described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0152] In the various embodiments of this invention, the functional units can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0153] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the embodiments of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as flash memory, portable hard disk, read-only memory, random access memory, magnetic disk, or optical disk.

[0154] The above description is merely a specific implementation of the embodiments of the present invention, but the protection scope of the embodiments of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed in the embodiments of the present invention should be covered within the protection scope of the embodiments of the present invention. Therefore, the protection scope of the embodiments of the present invention should be determined by the protection scope of the claims.

Claims

1. A method for detecting thermal runaway of a power battery based on a 48V voltage pulse, characterized in that, include: S101. Using the vehicle's 48V low-voltage battery as an excitation source, apply a short pulse to the high-voltage power battery pack under test through a switch array. S102. Real-time acquisition of voltage, current and temperature signals of the high-voltage power battery pack during the application of short pulses; S103. The primary thermal sensitivity factor is calculated based on the voltage, current and temperature signals during the short pulse process. S104. If the primary sensitive factor is less than or equal to the first preset threshold, continue the above steps; otherwise, proceed to the next step. S105. Using the vehicle's 48V low-voltage battery as the excitation source, apply medium and high pulses to the high-voltage power battery pack under test through a switch array. S106. Real-time acquisition of voltage, current and temperature signals of the high-voltage power battery pack during the application of medium and high pulses; S107. The complete thermal sensitivity factor is calculated based on the voltage, current and temperature signals during medium and high pulse processes. S108. If the complete thermal sensitivity factor is greater than the second preset threshold, disconnect the high-voltage power battery pack relay; otherwise, record the detection and calculation data and return to step S101.

2. The method for detecting thermal runaway of a power battery based on a 48V voltage pulse according to claim 1, characterized in that, The short pulse has a pulse width of 10ms and is used to capture sudden changes in ohmic internal resistance. The pulse width of the medium pulse is 1 second, used to monitor changes in polarization impedance; The long pulse has a pulse width of 10s and is used to analyze the diffusion time constant.

3. The method for detecting thermal runaway of a power battery based on a 48V voltage pulse according to claim 1, characterized in that, The switch array is a MOSFET switch array with a switching frequency of 100kHz.

4. The method for detecting thermal runaway of a power battery based on a 48V voltage pulse according to claim 2, characterized in that, Real-time acquisition of voltage, current, and temperature signals of the high-voltage power battery pack during the application of short pulses, including: Under short pulse conditions, the open-circuit voltage of the high-voltage power battery before the pulse, the minimum voltage after the pulse, the peak current, and the high-voltage battery pack temperature after the pulse are collected respectively, and the preset temperature compensation coefficient of the corresponding battery pack is obtained.

5. The method for detecting thermal runaway of a power battery based on a 48V voltage pulse according to claim 4, characterized in that, The primary thermal sensitivity factor is calculated based on the voltage, current, and temperature signals during the short pulse process, including: Based on the acquired signal, the change in ohmic internal resistance ΔR based on the short-pulse response is calculated. Ω , Based on ΔR Ω and reference ohmic internal resistance R Ω0 The primary heat sensitivity factor was calculated. The formula is as follows: 。 6. The method for detecting thermal runaway of a power battery based on a 48V voltage pulse according to claim 5, characterized in that, The change in ohmic internal resistance ΔR based on the short-pulse response Ω The calculation steps are as follows: The formula for calculating polarization resistance is as follows: ； Among them, V ocv The open-circuit voltage of the high-voltage power battery before the pulse, V min The lowest voltage value after the pulse, I peak K represents the peak current, T represents the high-voltage battery pack temperature after the pulse, and K represents the voltage level. T The preset temperature compensation coefficient for the battery pack; The formula for calculating the change in ohmic internal resistance is as follows: 。 7. The method for detecting thermal runaway of a power battery based on a 48V voltage pulse according to claim 6, characterized in that, Real-time acquisition of voltage, current, and temperature signals of the high-voltage power battery pack during the application of a medium-voltage pulse, including: Under medium-pulse conditions, the following data were collected: the time at the start of the high-voltage power battery, the time at the end of the pulse, the voltage at time t during the voltage recovery period after the pulse ends, the open-circuit voltage of the high-voltage power battery before the pulse, and the current value of the high-voltage power battery at time t.

8. The method for detecting thermal runaway of a power battery based on a 48V voltage pulse according to claim 7, characterized in that, Real-time acquisition of voltage, current, and temperature signals of the high-voltage power battery pack during the application of high pulses, including: Under long pulse conditions, the steady-state recovery voltage, instantaneous voltage at the end of the pulse, and steady-state voltage during the voltage recovery period after the pulse end of the high-voltage power battery at time t after the pulse ends were collected.

9. The method for detecting thermal runaway of a power battery based on a 48V voltage pulse according to claim 8, characterized in that, The complete thermal sensitivity factor is calculated based on the voltage, current, and temperature signals during medium and high pulse processes. The polarization impedance change based on the mid-pulse response was calculated; The diffusion time constant was calculated. The complete thermal sensitivity factor is calculated based on the polarization impedance change and diffusion time constant.

10. The method for detecting thermal runaway of a power battery based on a 48V voltage pulse according to claim 9, characterized in that, Based on the acquired signal, the polarization impedance change based on the mid-pulse response is calculated, including the following steps: The polarization impedance is calculated using the following formula: ； Where t0 is the time at the start of the pulse, t1 is the time at the end of the pulse, V(t) is the voltage at time t during the voltage recovery period after the pulse ends, and V... OCV The open-circuit voltage of the high-voltage power battery before the pulse, and the current value of the high-voltage power battery at time t (I(t)). The formula for calculating the change in polarization impedance is as follows: ； Among them, R p0 The reference ohmic impedance is used.

11. The method for detecting thermal runaway of a power battery based on a 48V voltage pulse according to claim 10, characterized in that, The diffusion time constant is calculated using the following formula: ； Wherein, V(t) is the steady-state recovery voltage of the high-voltage power battery at time t after the end of the pulse under long pulse conditions, V1 is the instantaneous voltage at the end of the pulse, and V0 is the steady-state voltage during the voltage recovery period after the end of the pulse.

12. The method for detecting thermal runaway of a power battery based on a 48V voltage pulse according to claim 9, characterized in that, The complete thermal sensitivity factor is calculated based on the polarization impedance change and diffusion time constant, including: ； Where α and β are weighting coefficients, γ is the diffusion impedance weight, and t c is the time decay constant.

13. A power battery thermal runaway detection device based on a 48V voltage pulse, characterized in that, include: The acquisition unit is used to acquire short pulses, medium pulses, and high pulses applied to the high-voltage power battery pack under test by the vehicle's 48V low-voltage battery as the excitation source through a switch array; The acquisition unit is used to acquire voltage, current and temperature signals of the high-voltage power battery pack in real time during the application of short pulses, medium pulses and high pulses; The calculation unit is used to calculate the primary thermal sensitivity factor and the complete thermal sensitivity factor based on the voltage signal, current signal and temperature signal during short pulse, medium pulse and high pulse processes; The judgment unit is used to determine that if the primary sensitive factor is less than or equal to the first preset threshold, the above steps continue to be repeated; if the complete thermal sensitive factor is greater than the second preset threshold, the high-voltage power battery pack relay is disconnected.

14. An electronic device, characterized in that, The device includes a memory and a processor, wherein the memory stores a computer program that can run on the processor, and when the computer program is executed by the processor, causes the processor to implement the method as described in any one of claims 1 to 12.

15. A computer-readable storage medium storing a computer program therein, characterized in that, When the computer program is executed by a processor, it implements the method as described in any one of claims 1 to 12.

Images