Temperature monitoring method of power battery system, battery management system and storage medium

Abstract

The present invention discloses a temperature monitoring method, a battery management system and a storage medium for a power battery system, the method comprising: obtaining current module temperature sampling results of several modules in the power battery system; predicting the internal temperature of battery cells in the several modules according to the current module temperature sampling results of the several modules, and obtaining the battery cell temperature prediction results of the several modules; performing thermal runaway detection on the power battery system according to the current module temperature sampling results of the several modules, the battery cell temperature prediction results and a preset thermal runaway condition set, and obtaining the thermal runaway detection result; and controlling the state of the power battery system according to the thermal runaway detection result. By adopting the embodiments of the present invention, the power battery system can be reliably and effectively temperature monitored, and the state of the power battery system can be controlled accordingly, thereby improving driving safety.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a temperature monitoring method, a battery management system and a storage medium for a power battery system. Background Art

[0002] As the electrification of automobiles continues to deepen, the electronic and electrical networks of vehicles have gradually become highly integrated and complex, which has also caused many automobile safety accidents. Most of the safety accidents are caused by the failure of the relevant safety functions of the control system itself. As one of the core key components of new energy vehicles, the safety of the power battery system affects the future development direction of new energy vehicles. The power battery system is a complex nonlinear large inertia system, in which the battery temperature is a physical quantity that directly represents the thermal state of the battery. Excessive battery temperature is the most direct trigger factor when the battery has a thermal runaway event. Therefore, it is very important to monitor the temperature of the power battery system in real time, accurately and effectively.

[0003] At present, the key physical parameters that can be directly measured to characterize the state of the power battery system include module temperature, voltage and current. Therefore, in the prior art, the battery module temperature of the power battery system is directly collected through the battery management system (Battery Management System, BMS), and it is determined whether the battery module temperature exceeds the preset temperature threshold, so as to monitor whether the power battery system has thermal runaway. However, in the process of implementing the present invention, the inventors found that due to the large difference between the battery module temperature and the internal temperature of the battery cell, it is easy for the internal temperature of the battery to be overheated while the battery module temperature is still normal. Therefore, the effectiveness and reliability of the temperature monitoring of the power battery system using the above-mentioned method in the prior art are low, which is easy to affect driving safety. Summary of the invention

[0004] The embodiments of the present invention provide a temperature monitoring method, a battery management system and a storage medium for a power battery system, which can reliably and effectively monitor the temperature of the power battery system and control the state of the power battery system accordingly, thereby improving driving safety.

[0005] An embodiment of the present invention provides a temperature monitoring method for a power battery system, which is executed by a main controller in a battery management system. The method includes:

[0006] Obtain current module temperature sampling results of several modules in the power battery system;

[0007] Predicting the internal temperatures of the battery cells in the plurality of modules according to the current module temperature sampling results of the plurality of modules to obtain the battery cell temperature prediction results of the plurality of modules;

[0008] Performing thermal runaway detection on the power battery system according to current module temperature sampling results of the plurality of modules, battery cell temperature prediction results, and a preset thermal runaway condition set to obtain a thermal runaway detection result;

[0009] The state of the power battery system is controlled according to the thermal runaway detection result.

[0010] As an improvement of the above scheme, the battery management system also includes a slave controller; the slave controller includes a single chip microcomputer, a plurality of temperature sensors and a plurality of temperature acquisition circuits connected to each of the temperature sensors in a one-to-one correspondence; the plurality of temperature sensors are arranged in a plurality of modules in the power battery system, and the number of temperature sensors arranged in each of the modules is at least two; the single chip microcomputer is used to control the plurality of temperature acquisition circuits to collect signals from the plurality of temperature sensors, and perform collection completion status diagnosis and electrical diagnosis on the plurality of temperature acquisition circuits, so as to obtain initial temperature sampling results, collection completion status diagnosis results and electrical diagnosis results of the plurality of modules and send them to the main controller;

[0011] The obtaining of current module temperature sampling results of several modules in the power battery system specifically includes:

[0012] Receiving initial temperature sampling results, collection completion status diagnosis results and electrical diagnosis results of the plurality of modules sent by the slave controller;

[0013] Determining whether initial temperature sampling results of the plurality of modules are valid according to the temperature sampling completion status diagnosis results and electrical diagnosis results of the plurality of modules;

[0014] For each of the modules, if the initial temperature sampling result of the module is valid, the initial temperature sampling result of the module is used as the current module temperature sampling result of the module; if the initial temperature sampling result of the module is invalid, the alternative values ​​of each temperature sampling value in the initial temperature sampling result of the module are obtained, and the alternative values ​​of each temperature sampling value are used as the current module temperature sampling result of the module.

[0015] As an improvement of the above solution, the method further includes:

[0016] A fault detection is performed on the communication status between the master controller and the slave controller, and when a communication fault is detected, the power battery system is controlled to enter a safe state.

[0017] As an improvement of the above solution, the internal temperature of the battery cells in the plurality of modules is predicted according to the current module temperature sampling results of the plurality of modules to obtain the battery cell temperature prediction results of the plurality of modules, which specifically includes:

[0018] Obtaining a moving average current of the power battery system within a preset time before a current moment;

[0019] Based on the corresponding relationship between the current magnitude and the temperature correction amount, the current temperature correction amount is determined according to the current moving average value;

[0020] The current module temperature sampling results of the plurality of modules are corrected according to the current temperature correction amount to obtain the battery cell temperature prediction results of the plurality of modules.

[0021] As an improvement of the above solution, the thermal runaway condition set includes a first condition set and a second condition set;

[0022] The thermal runaway detection result includes a first diagnosis result and a second diagnosis result;

[0023] Then, the thermal runaway detection is performed on the power battery system according to the current module temperature sampling results of the plurality of modules, the battery cell temperature prediction results and the preset thermal runaway condition set to obtain the thermal runaway detection result, which specifically includes:

[0024] According to the current module temperature sampling results of the plurality of modules, determining whether the power battery system meets the conditions in the first condition set, and obtaining the first diagnosis result;

[0025] According to the current module temperature sampling results of the plurality of modules and the battery cell temperature prediction results, it is determined whether the power battery system meets the conditions in the second condition set to obtain the second diagnosis result.

[0026] As an improvement of the above solution, the current module temperature sampling result includes at least two temperature sampling values;

[0027] The first condition set specifically includes at least one of the following conditions:

[0028] The maximum temperature sampling value of at least one module in the power battery system exceeds a preset first temperature range;

[0029] The sampling temperature change rate of at least one module in the power battery system exceeds a preset first change rate threshold; wherein the sampling temperature change rate of each module is calculated based on the current module temperature sampling result and historical temperature sampling result data of the module;

[0030] The maximum temperature sample value in the power battery system exceeds a preset first temperature threshold;

[0031] The difference between the highest temperature sampling value and the lowest temperature sampling value of at least one module in the power battery system exceeds a preset temperature difference threshold.

[0032] As an improvement of the above solution, the second condition set specifically includes at least one of the following conditions:

[0033] The maximum temperature sampling value of at least one module in the power battery system exceeds a preset second temperature range;

[0034] The predicted temperature change rate of the battery cells of at least one module in the power battery system exceeds a preset second change rate threshold; wherein the predicted temperature change rate of the battery cells of each module is calculated based on the battery cell temperature prediction result of the module and the historical battery cell temperature prediction result data;

[0035] The predicted value of the highest battery cell temperature in the power battery system exceeds a preset second temperature threshold.

[0036] As an improvement of the above solution, controlling the state of the battery management system according to the thermal runaway detection result specifically includes:

[0037] Determining, according to the first diagnostic result and the second diagnostic result, whether the power battery system satisfies at least one condition in the first condition set and at least one condition in the second condition set;

[0038] When it is determined that the power battery system does not satisfy any condition in the first condition set and does not satisfy any condition in the second condition set, controlling the power battery system to operate normally;

[0039] When it is determined that the power battery system satisfies at least one condition in the first condition set and satisfies at least one condition in the second condition set, controlling the power battery system to enter a safe state;

[0040] When it is determined that the power battery system satisfies only at least one condition in the first condition set or only satisfies at least one condition in the second condition set, the power battery system is controlled to perform power degradation.

[0041] As an improvement of the above solution, when it is determined that the power battery system only satisfies at least one condition in the first condition set or only satisfies at least one condition in the second condition set, after controlling the power battery system to perform power degradation, the method further includes:

[0042] Repeat the steps of obtaining the current module temperature sampling results of the plurality of modules to obtaining the thermal runaway detection results until one of the stop execution conditions is met, and judge whether the power battery system meets at least one condition in the first condition set and at least one condition in the second condition set according to the current first diagnosis result and the current second diagnosis result; wherein the stop execution condition at least includes that the time for repeatedly performing the above steps reaches a preset time threshold;

[0043] If it is determined that the power battery system does not satisfy any condition in the first condition set and does not satisfy any condition in the second condition set, the power battery system is controlled to operate normally; otherwise, the power battery system is controlled to enter a safe state.

[0044] As an improvement of the above solution, the main controller includes at least two cores;

[0045] The step of determining whether the power battery system satisfies a condition in the first condition set according to the current module temperature sampling results of the plurality of modules, and obtaining the first diagnosis result is performed by the first core of the main controller;

[0046] The step of predicting the internal temperatures of the battery cells in the several modules based on the current module temperature sampling results of the several modules to obtain the battery cell temperature prediction results of the several modules, and the step of judging whether the power battery system satisfies the conditions in the second condition set based on the current module temperature sampling results and the battery cell temperature prediction results of the several modules to obtain the second diagnostic result are executed by the second core of the main controller.

[0047] As an improvement of the above solution, the method further comprises the steps of:

[0048] Data flow monitoring and program flow monitoring are performed on the first core and the second core, and when it is monitored that a data flow abnormality or a program flow abnormality occurs in one of the first core and the second core, the power battery system is controlled to enter a safe state.

[0049] Another embodiment of the present invention provides a battery management system, including a main controller;

[0050] Wherein, the main controller specifically includes:

[0051] A sampling module, used to obtain current module temperature sampling results of several modules in the power battery system;

[0052] A prediction module, used to predict the internal temperature of the battery cells in the plurality of modules according to the current module temperature sampling results of the plurality of modules, so as to obtain the battery cell temperature prediction results of the plurality of modules;

[0053] A detection module, configured to perform thermal runaway detection on the power battery system according to current module temperature sampling results of the plurality of modules, battery cell temperature prediction results and a preset thermal runaway condition set, to obtain a thermal runaway detection result;

[0054] A control module is used to control the state of the battery management system according to the thermal runaway detection result.

[0055] Another embodiment of the present invention provides a battery management system, including a main controller; the main controller includes a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, and when the processor executes the computer program, it implements the temperature monitoring method of the power battery system described in any one of the above.

[0056] Another embodiment of the present invention provides a computer-readable storage medium, which includes a stored computer program, wherein when the computer program is running, the device where the computer-readable storage medium is located is controlled to execute the temperature monitoring method of the power battery system as described in any one of the above.

[0057] Compared with the prior art, the temperature monitoring method, battery management system and storage medium of the power battery system provided by the embodiment of the present invention first obtain the current module temperature sampling results of several modules in the power battery system, then predict the internal temperature of the battery cells in the several modules according to the current module temperature sampling results of the several modules, and obtain the battery cell temperature prediction results of the several modules, then perform thermal runaway detection on the power battery system according to the current module temperature sampling results of the several modules, the battery cell temperature prediction results and the preset thermal runaway condition set to obtain the thermal runaway detection result, and then control the state of the power battery system according to the thermal runaway detection result, so as to realize the temperature monitoring of the power battery system. It can be seen that the temperature monitoring method, battery management system and storage medium of the power battery system provided by the embodiment of the present invention comprehensively consider the module temperature and the internal temperature of the battery cell of the power battery system when performing thermal runaway detection, so that the power battery system can be reliably and effectively temperature monitored, and the state of the power battery system can be controlled accordingly according to the thermal runaway detection result, so as to effectively improve driving safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1is a flow chart of a temperature monitoring method for a power battery system provided by an embodiment of the present invention;

[0059] Figure 2a is a structural schematic diagram of a battery management system provided by an embodiment of the present invention;

[0060] Figure 2b It is a logic schematic diagram of a single-chip microcomputer of a slave controller of a battery management system provided by an embodiment of the present invention;

[0061] Figure 2c It is a logic schematic diagram of a microprocessor of a main controller of a battery management system provided by one embodiment of the present invention;

[0062] Figure 3 is a structural schematic diagram of a battery management system provided by another embodiment of the present invention;

[0063] Figure 4 It is a structural schematic diagram of a battery management system provided by another embodiment of the present invention. DETAILED DESCRIPTION

[0064] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0065] See also Figure 1 , is a flow chart of a temperature monitoring method for a power battery system provided by an embodiment of the present invention.

[0066] The temperature monitoring method of the power battery system provided by the embodiment of the present invention is executed by a main controller in the battery management system, and the method includes:

[0067] S11. Obtain current module temperature sampling results of several modules in the power battery system.

[0068] S12: predicting the internal temperatures of the battery cells in the modules according to the current module temperature sampling results of the modules to obtain the battery cell temperature prediction results of the modules.

[0069] S13, performing thermal runaway detection on the power battery system according to current module temperature sampling results of the plurality of modules, battery cell temperature prediction results and a preset thermal runaway condition set to obtain a thermal runaway detection result.

[0070] S14. Controlling the state of the power battery system according to the thermal runaway detection result.

[0071] It should be noted that, in specific implementation, the thermal runaway condition set can be set according to actual needs, for example, it can be set to determine thermal runaway when the current module temperature sampling result is greater than a preset value, or it can be set to determine thermal runaway when the battery cell temperature prediction result is greater than another preset value, etc., without limitation here.

[0072] Exemplarily, step S14 may specifically be to control the power battery system to reduce power or to stop running when the thermal runaway detection result indicates that thermal runaway has occurred, and to control the power battery system to operate normally when the thermal runaway detection result indicates that thermal runaway has not occurred.

[0073] The temperature monitoring method of the power battery system provided by the embodiment of the present invention first obtains the current module temperature sampling results of several modules in the power battery system, and then predicts the internal temperature of the battery cells in the several modules according to the current module temperature sampling results of the several modules to obtain the battery cell temperature prediction results of the several modules, and then performs thermal runaway detection on the power battery system according to the current module temperature sampling results of the several modules, the battery cell temperature prediction results and the preset thermal runaway condition set to obtain the thermal runaway detection result, and then controls the state of the power battery system according to the thermal runaway detection result, thereby realizing the temperature monitoring of the power battery system. It can be seen that the temperature monitoring method of the power battery system, the battery management system and the storage medium provided by the embodiment of the present invention comprehensively consider the module temperature of the power battery system and the internal temperature of the battery cell when performing thermal runaway detection, so that the power battery system can be reliably and effectively temperature monitored, and the state of the power battery system can be controlled accordingly according to the thermal runaway detection result, so that driving safety can be effectively improved.

[0074] Based on the above embodiment, as a first optional embodiment, see Figure 2a , the battery management system also includes a slave controller; the slave controller includes a single-chip microcomputer, a plurality of temperature sensors and a plurality of temperature acquisition circuits connected to each of the temperature sensors in a one-to-one correspondence; the plurality of temperature sensors are arranged in a plurality of modules in the power battery system, and the number of temperature sensors arranged in each of the modules is at least two; the single-chip microcomputer is used to control the plurality of temperature acquisition circuits to collect signals from the plurality of temperature sensors, and perform collection completion status diagnosis and electrical diagnosis on the plurality of temperature acquisition circuits, so as to obtain initial temperature sampling results, collection completion status diagnosis results and electrical diagnosis results of the plurality of modules and send them to the main controller.

[0075] Then the step S11 specifically includes:

[0076] S110, receiving the initial temperature sampling results, collection completion status diagnosis results and electrical diagnosis results of the plurality of modules sent by the slave controller;

[0077] S111, judging whether the initial temperature sampling results of the plurality of modules are valid according to the temperature sampling completion status diagnosis results and electrical diagnosis results of the plurality of modules;

[0078] S112. For each of the modules, if the initial temperature sampling result of the module is valid, the initial temperature sampling result of the module is used as the current module temperature sampling result of the module; if the initial temperature sampling result of the module is invalid, a replacement value of each temperature sampling value in the initial temperature sampling result of the module is obtained, and the replacement value of each temperature sampling value is used as the current module temperature sampling result of the module.

[0079] Among them, the processing logic of the single chip microcomputer is as follows Figure 2b As shown, no further description is given here.

[0080] Preferably, the temperature sensors arranged in the same module can be of different specifications and ranges and different brands, and the temperature sensing ranges and resolutions are different, which can effectively reduce the occurrence of simultaneous failure of the temperature sensors.

[0081] Optionally, the filter processing circuit of the temperature sampling circuit is required to be designed with different filter cutoff frequencies, and the reference voltage sources of the two ADCs are required to be independent of each other, which can effectively reduce the occurrence of simultaneous failure of the temperature sampling circuits.

[0082] Among them, the intelligent programmable components used in the controller can ensure that the minimum system of the microcontroller (CPU, memory, communication, I / O, etc.) meets the high diagnostic coverage requirements of ASIL D (single point fault coverage ≥ 99%, latent fault coverage ≥ 90%).

[0083] Preferably, in order to ensure that the temperature signal does not jump when using the alternative value and cause the misjudgment of temperature abnormality fault, and at the same time to ensure the independence of the temperature sampling values, for each module, each temperature sampling value in the current module temperature sampling result should be replaced by a normal value from different sources. For example, if the current module temperature sampling result of a module contains two temperature sampling values, the first temperature sampling value is replaced by the normal value of the previous sampling, and the second temperature sampling value is replaced by the value obtained by averaging other valid temperature sampling values ​​in the current sampling period.

[0084] It is worth noting that the ISO26262 road vehicle electronic and electrical functional safety standard is currently the most advanced engineering development method in the automotive field. It proposes requirements for all processes covering the entire life cycle of automotive electronic functional safety development, and reduces the risk of electronic and electrical control systems to an acceptable range by avoiding and controlling systemic failures and random hardware failures. ISO26262 proposes to use the automotive safety integrity level (ASIL) to evaluate the risk reduction requirements of safety functions, among which ASILD is the highest safety level requirement. The technical requirements of ASILD are: system hardware architecture metrics (single point fault coverage ≥ 99%, latent fault coverage ≥ 90%), and random hardware failure rate indicators (<10Fit). In this embodiment, the battery management system adopts a heterogeneous redundant hardware architecture. Since heterogeneous redundancy can ensure the independence between signal paths, there is no common cause failure and cascading failure. Therefore, it is a safety mechanism with a diagnostic coverage rate of 99% (even 100% for simple components), which can cover almost all failure modes of a certain component. It can be seen that the power battery system provided by the embodiment of the present invention can meet the high diagnostic coverage requirements of ASIL D for temperature monitoring, and the slave controller collects the sensor signal of each temperature sensor through an independent temperature acquisition circuit. Compared with collecting the sensor signals of all temperature sensors through the same temperature acquisition circuit, it can effectively avoid the situation where all sampling results are inaccurate due to failure of the temperature acquisition circuit, thereby further improving the reliability and effectiveness of temperature monitoring of the power battery system. In addition, the prior art lacks reliability and validity diagnosis of temperature sampling data. In this embodiment, after receiving the initial temperature sampling results of several modules, the main controller also judges the electrical validity of the sampling state based on the temperature sampling completion state diagnosis results and electrical diagnosis results corresponding to the several modules, and when it is found that the initial temperature sampling result of a module is invalid, a suitable substitute value is used as the current module temperature sampling result of the module, which can further improve the reliability and effectiveness of temperature monitoring of the power battery system.

[0085] Furthermore, the method further comprises:

[0086] S113, performing fault detection on the communication status between the master controller and the slave controller, and controlling the power battery system to enter a safe state when a communication fault is detected.

[0087] It should be noted that if a communication failure occurs between the master controller and the slave controller, it will easily affect the reliability of temperature monitoring. In this embodiment, by performing fault detection on the communication status between the master controller and the slave controller, and controlling the power battery system to enter a safe state when a communication failure is detected, it can effectively prevent the failure to timely control the temperature of the power battery system due to misjudgment or missed judgment of thermal runaway caused by communication failure, and can further improve the reliability and effectiveness of temperature monitoring of the power battery system.

[0088] For example, in order to meet the ASIL D requirements, the communication fault diagnosis between the master controller and the slave controller must cover at least seven communication failure modes, including message duplication, message loss, unexpected message insertion, message sequence error, message damage, message delay, and false message. Therefore, in actual applications, the following safety mechanisms must be used simultaneously to cover all of the above seven communication failure types:

[0089] (1) Encapsulate all temperature sampling signals into the same frame message, use a unique message ID to identify and use a frame counter to monitor message sending. If the temperature signal exceeds 8 bytes, a multi-frame transmission protocol must be used;

[0090] (2) A Checksum / CRC mechanism is used for the temperature signal message with a Hamming distance of at least 3;

[0091] (3) A timeout monitoring mechanism is used for periodically sent messages.

[0092] Among them, the timeout monitoring threshold should be 100ms±10ms; the Hamming distance of the Checksum / CRC mechanism should be no less than 3.

[0093] Based on the above embodiment, as a second optional embodiment, step S12 specifically includes:

[0094] S120, obtaining a moving average current of the power battery system within a preset time before a current moment;

[0095] S121, based on the corresponding relationship between the current magnitude and the temperature correction amount, determine the current temperature correction amount according to the current moving average value;

[0096] S122: Correct the current module temperature sampling results of the plurality of modules according to the current temperature correction amount to obtain battery cell temperature prediction results of the plurality of modules.

[0097] It should be noted that, in specific implementation, the preset time can be set according to actual conditions, and is not limited here. Optionally, considering the thermal runaway requirements of the battery, the preset time can be set to 5 minutes.

[0098] Among them, the corresponding relationship between the current magnitude and the temperature correction amount can be obtained through offline calibration, specifically, by obtaining the temperature correction amount under different operating current excitation conditions through battery pack bench testing, thereby obtaining the above-mentioned corresponding relationship.

[0099] In this embodiment, based on the principle that the heating power is related to the current size and time, the moving average value of the current of the power battery system within the preset time before the current moment is taken, and then based on the corresponding relationship between the current size and the temperature correction amount, the current temperature correction amount is determined according to the current moving average value. The current module temperature sampling results of several modules are corrected by the current temperature correction amount, so as to obtain accurate battery cell temperature prediction results of several modules, which can effectively ensure the reliability and effectiveness of temperature monitoring of the power battery system.

[0100] Preferably, the step S120 specifically includes:

[0101] S1201, obtaining a current value of the power battery system within a preset time before a current moment;

[0102] S1202, filtering the current value within the preset time to obtain a filtered current value within the preset time;

[0103] S1203, calculating the moving average of the filtered current value within the preset time, to obtain the moving average of the current of the power battery system within the preset time before the current moment.

[0104] It should be noted that in this embodiment, since the current value within the preset time is filtered and then the moving average is calculated, the noise in the current value within the preset time can be effectively removed, so the accuracy of the moving average value of the current within the preset time can be effectively improved, thereby further improving the reliability of temperature monitoring of the power battery system.

[0105] Based on the above embodiment, as a third optional embodiment, the thermal runaway condition set includes a first condition set and a second condition set;

[0106] The thermal runaway detection result includes a first diagnosis result and a second diagnosis result;

[0107] Then the step S13 specifically includes:

[0108] S130, judging whether the power battery system satisfies a condition in the first condition set according to the current module temperature sampling results of the plurality of modules, and obtaining the first diagnosis result;

[0109] S131. Determine whether the power battery system satisfies a condition in the second condition set according to current module temperature sampling results of the plurality of modules and battery cell temperature prediction results, and obtain the second diagnosis result.

[0110] In this embodiment, temperature data at different levels are used to perform thermal runaway diagnosis twice, thereby achieving temperature monitoring with high diagnostic coverage.

[0111] Furthermore, the current module temperature sampling result includes at least two temperature sampling values;

[0112] The first condition set specifically includes at least one of the following conditions:

[0113] Item 1: The maximum temperature sampling value of at least one module in the power battery system exceeds a preset first temperature range;

[0114] Item 2: The sampling temperature change rate of at least one module in the power battery system exceeds a preset first change rate threshold; wherein the sampling temperature change rate of each module is calculated based on the current module temperature sampling result and historical temperature sampling result data of the module;

[0115] Item 3: The highest temperature sampling value in the power battery system exceeds a preset first temperature threshold;

[0116] Item 4: The difference between the highest temperature sampling value and the lowest temperature sampling value of at least one module in the power battery system exceeds a preset temperature difference threshold.

[0117] Among them, the first temperature range can be determined according to the actual physical characteristics of the power battery system, which is not limited here. Optionally, the first temperature range is -40℃~85℃; the first change rate threshold refers to the threshold of the change rate dTemp / dt of the battery module temperature under normal circumstances. Optionally, the first change rate threshold is less than 1℃ / s; different first temperature thresholds can be set for battery modules of different material systems. Specifically, the first temperature threshold can be set according to the battery cell test parameters, which is not limited here. For example, the first temperature threshold corresponding to the ternary battery can be set to 60℃, while the first temperature threshold corresponding to the lithium iron phosphate battery can be set to 80℃; the preset temperature difference threshold can be set according to the battery cell test parameters, which is not limited here.

[0118] It is worth noting that the first condition set includes thermal runaway conditions at the module level and the battery pack level, and thus can effectively improve the diagnostic coverage of temperature monitoring of the power battery system.

[0119] Furthermore, the second condition set specifically includes at least one of the following conditions:

[0120] Item 1: The maximum temperature sampling value of at least one module in the power battery system exceeds a preset second temperature range;

[0121] Item 2: The predicted temperature change rate of a battery cell of at least one module in the power battery system exceeds a preset second change rate threshold; wherein the predicted temperature change rate of a battery cell of each module is calculated based on the battery cell temperature prediction result of the module and the historical battery cell temperature prediction result data;

[0122] Item 3: The predicted value of the highest battery cell temperature in the power battery system exceeds a preset second temperature threshold.

[0123] Among them, the second temperature range is the engineering application temperature range of the battery module. Preferably, the second temperature range is -20℃~85℃; the second change rate threshold refers to the threshold of the change rate of the battery cell temperature under normal circumstances. Optionally, the second change rate threshold is less than 1℃ / s; different second temperature thresholds can be set for battery cells of different material systems, which are not limited here.

[0124] It is worth noting that the second condition set includes thermal runaway conditions at the module level and the cell level, and thus can effectively improve the diagnostic coverage of temperature monitoring of the power battery system.

[0125] Specifically, the step S14 includes:

[0126] S140, judging whether the power battery system satisfies at least one condition in the first condition set and at least one condition in the second condition set according to the first diagnostic result and the second diagnostic result;

[0127] S141: when it is determined that the power battery system does not satisfy any condition in the first condition set and does not satisfy any condition in the second condition set, controlling the power battery system to operate normally;

[0128] S142: when it is determined that the power battery system satisfies at least one condition in the first condition set and satisfies at least one condition in the second condition set, controlling the power battery system to enter a safe state;

[0129] S143: When it is determined that the power battery system satisfies only at least one condition in the first condition set or only satisfies at least one condition in the second condition set, control the power battery system to perform power degradation.

[0130] In this embodiment, the state of the power battery system can be accurately controlled by comprehensively considering the first diagnosis result and the second diagnosis result.

[0131] Further, when it is determined that the power battery system satisfies only at least one condition in the first condition set or only satisfies at least one condition in the second condition set, after controlling the power battery system to perform power degradation, the method further includes:

[0132] S1431, repeatedly executing the steps from S11 to S13 until one of the stop execution conditions is met, and judging whether the power battery system meets at least one condition in the first condition set and at least one condition in the second condition set according to the current first diagnostic result and the current second diagnostic result; wherein the stop execution condition at least includes that the time for repeatedly executing the steps from S11 to S13 reaches a preset time threshold;

[0133] S1432: If it is determined that the power battery system does not satisfy any condition in the first condition set and does not satisfy any condition in the second condition set, control the power battery system to operate normally; otherwise, control the power battery system to enter a safe state.

[0134] Among them, the preset time threshold is the fault tolerance time. For cells with different chemical systems, the fault tolerance time (FTTI) will be different. It can be obtained based on the actual measured data of the battery and is generally set to 5s.

[0135] Preferably, the stopping execution condition also includes:

[0136] According to the current first diagnosis result and the current second diagnosis result, it is determined that the power battery system satisfies at least one condition in the first condition set and at least one condition in the second condition set; and

[0137] According to the current first diagnostic result and the current second diagnostic result, it is determined that the power battery system does not satisfy any condition in the first condition set and does not satisfy any condition in the second condition set.

[0138] It is worth noting that in this embodiment, if the two diagnostic results are inconsistent, the system power is first downgraded, and then the judgment is continued to be extended. If the diagnostic results are still different within the fault tolerance time, the control system immediately enters a safe state. This can prevent the power battery system from being mistakenly adjusted to a safe state due to diagnostic errors, thereby improving the reliability and effectiveness of temperature monitoring of the power battery system.

[0139] Exemplarily, the safe state is defined as follows:

[0140] (1) If the first diagnosis result satisfies the first condition, the second condition or the fourth condition in the first condition set, or the second diagnosis result satisfies the first condition and the second condition in the second condition set, then the safe state is to adopt the power reduction mechanism;

[0141] (2) If the first diagnostic result satisfies the third condition in the first condition set, or the second diagnostic result satisfies the third condition in the first condition set, the safe state is to cut off the high-voltage relay in the power battery system within the fault tolerance time (FTTI) and report to the instrument to prompt the user.

[0142] Among them, the power degradation mechanism is to reduce the continued accumulation of battery heat by reducing the system allowable power. For example, the power can be temporarily reduced to 50% of the original, and the power can be restored when the battery temperature drops to a controllable range.

[0143] Preferably, the main controller includes at least two cores;

[0144] The step of determining whether the power battery system satisfies a condition in the first condition set according to the current module temperature sampling results of the plurality of modules, and obtaining the first diagnosis result is performed by the first core of the main controller;

[0145] The step of predicting the internal temperatures of the battery cells in the several modules based on the current module temperature sampling results of the several modules to obtain the battery cell temperature prediction results of the several modules, and the step of judging whether the power battery system satisfies the conditions in the second condition set based on the current module temperature sampling results and the battery cell temperature prediction results of the several modules to obtain the second diagnostic result are executed by the second core of the main controller.

[0146] In this embodiment, the two diagnostic processes are executed by different independent cores, ensuring that the hardware is completely independent. This ensures that when a core fails, another core can still complete the diagnosis of thermal runaway, thereby effectively improving the effectiveness and reliability of temperature monitoring of the power battery system.

[0147] Furthermore, the method further comprises the steps of:

[0148] S15. Perform data flow monitoring and program flow monitoring on the first core and the second core, and when it is monitored that a data flow abnormality or a program flow abnormality occurs in one of the first core and the second core, control the power battery system to enter a safe state.

[0149] In this embodiment, by performing data flow monitoring and program flow monitoring on the first core and the second core, and controlling the power battery system to enter a safe state when a data flow abnormality or a program flow abnormality is detected in one of the first core and the second core, misdiagnosis or missed diagnosis caused by data flow abnormality or program flow abnormality can be prevented, thereby effectively ensuring accurate and reliable temperature monitoring.

[0150] Exemplarily, the data flow monitoring requirements are as follows: ① Variables related to the temperature signal must be stored in an independent storage space, and an EDC / ECC verification mechanism with more than 3 redundant bits must be used to check the temperature values ​​entering and leaving the independent storage space; ② Only functional modules that meet the ASIL D requirements have the authority to read and write the temperature signal; ③ The inter-core communication between the first core and the second core must use an E2E communication verification mechanism to ensure data integrity.

[0151] The program flow monitoring requirements are as follows: a checkpoint must be set at the beginning of the program flow of each safety mechanism, and a window watchdog is used to monitor whether the triggering time and triggering order of each checkpoint are normal.

[0152] In a specific embodiment, the steps S12, S13, S14 and S15 may be performed by a microprocessor of the main controller, and the structure and processing logic of the microprocessor may be as follows: Figure 2c As shown, no further elaboration is given here.

[0153] See also Figure 3 , is a structural diagram of a battery management system provided by another embodiment of the present invention.

[0154] The battery management system provided by the embodiment of the present invention includes a main controller 1;

[0155] Wherein, the main controller 1 specifically includes:

[0156] The sampling module 11 is used to obtain the current module temperature sampling results of several modules in the power battery system;

[0157] A prediction module 12, configured to predict the internal temperatures of the battery cells in the plurality of modules according to the current module temperature sampling results of the plurality of modules, and obtain the battery cell temperature prediction results of the plurality of modules;

[0158] A detection module 13, configured to perform thermal runaway detection on the power battery system according to current module temperature sampling results of the plurality of modules, battery cell temperature prediction results and a preset thermal runaway condition set, to obtain a thermal runaway detection result;

[0159] The control module 14 is used to control the state of the battery management system according to the thermal runaway detection result.

[0160] Among them, all relevant contents of each step involved in the above method embodiment can be referred to the functional description of the corresponding functional module, and will not be repeated here.

[0161] The battery management system provided by the embodiment of the present invention first obtains the current module temperature sampling results of several modules in the power battery system, and then predicts the internal temperature of the battery cells in the several modules according to the current module temperature sampling results of the several modules to obtain the battery cell temperature prediction results of the several modules, and then performs thermal runaway detection on the power battery system according to the current module temperature sampling results of the several modules, the battery cell temperature prediction results and the preset thermal runaway condition set to obtain the thermal runaway detection result, and then controls the state of the power battery system according to the thermal runaway detection result, thereby realizing the temperature monitoring of the power battery system. It can be seen that the temperature monitoring method, battery management system and storage medium of the power battery system provided by the embodiment of the present invention comprehensively consider the module temperature of the power battery system and the internal temperature of the battery cell when performing thermal runaway detection, so that the power battery system can be reliably and effectively temperature monitored, and the state of the power battery system can be correspondingly controlled according to the thermal runaway detection result, so that driving safety can be effectively improved.

[0162] See also Figure 4 , is a schematic diagram of a battery management system provided by another embodiment of the present invention.

[0163] A battery management system provided in an embodiment of the present invention includes a main controller 30, wherein the main controller 30 includes a processor 301, a memory 302, and a computer program stored in the memory 302 and configured to be executed by the processor 301, and when the processor 301 executes the computer program, the temperature monitoring method of the power battery system described in any of the above embodiments is implemented.

[0164] When the processor 301 executes the computer program, the steps in the above-mentioned embodiment of the temperature monitoring method for the power battery system are implemented, for example Figure 1 Alternatively, when the processor 301 executes the computer program, the functions of each module / unit in the above-mentioned battery management system embodiment are realized, for example Figure 3 The functions of each module of the main controller of the battery management system are shown.

[0165] Exemplarily, the computer program may be divided into one or more modules, which are stored in the memory 302 and executed by the processor 301 to complete the present invention. The one or more modules may be a series of computer program instruction segments that can complete specific functions, and the instruction segments are used to describe the execution process of the computer program in the battery management system. For example, the computer program may be divided into a sampling module, a prediction module, a detection module and a control module, and the specific functions of each module are as follows: a sampling module for obtaining the current module temperature sampling results of several modules in the power battery system; a prediction module for predicting the internal temperature of the battery cells in the several modules according to the current module temperature sampling results of the several modules, and obtaining the battery cell temperature prediction results of the several modules; a detection module for performing thermal runaway detection on the power battery system according to the current module temperature sampling results of the several modules, the battery cell temperature prediction results and the preset thermal runaway condition set, and obtaining the thermal runaway detection result; a control module for controlling the state of the battery management system according to the thermal runaway detection result.

[0166] The battery management system may include, but is not limited to, a processor 301 and a memory 302. Those skilled in the art will appreciate that the schematic diagram is merely an example of a battery management system and does not limit the battery management system, and may include more or fewer components than shown in the diagram, or may combine certain components, or different components, for example, the battery management system may also include input and output devices, network access devices, buses, etc.

[0167] The processor 301 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc. The processor 301 is the control center of the main controller 30 of the battery management system, and uses various interfaces and lines to connect various parts of the main controller 30 of the entire battery management system.

[0168] The memory 302 can be used to store the computer program and / or module. The processor 301 implements various functions of the main controller 30 of the battery management system by running or executing the computer program and / or module stored in the memory 302 and calling the data stored in the memory 302. The memory 302 can mainly include a program storage area and a data storage area, wherein the program storage area can store an operating system, an application required for at least one function (such as a sound playback function, an image playback function, etc.); the data storage area can store data created according to the use of the battery management system (such as audio data, a phone book, etc.). In addition, the memory can include a high-speed random access memory, and can also include a non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), at least one disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0169] Wherein, if the module / unit integrated in the battery management system is implemented in the form of 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 present invention implements all or part of the process in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Wherein, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electrical carrier signal, telecommunication signal and software distribution medium, etc.

[0170] It should be noted that the device embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. In addition, in the accompanying drawings of the device embodiments provided by the present invention, the connection relationship between the modules indicates that there is a communication connection between them, which may be specifically implemented as one or more communication buses or signal lines. A person of ordinary skill in the art may understand and implement it without paying any creative effort.

[0171] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A temperature monitoring method for a power battery system, characterized in that: Executed by a main controller in a battery management system, the method includes: Obtain current module temperature sampling results of several modules in the power battery system; Predicting the internal temperatures of the battery cells in the plurality of modules according to the current module temperature sampling results of the plurality of modules to obtain the battery cell temperature prediction results of the plurality of modules; Performing thermal runaway detection on the power battery system according to current module temperature sampling results of the plurality of modules, battery cell temperature prediction results, and a preset thermal runaway condition set to obtain a thermal runaway detection result; Controlling the state of the power battery system according to the thermal runaway detection result; The thermal runaway condition set includes a first condition set and a second condition set; The thermal runaway detection result includes a first diagnosis result and a second diagnosis result; Then, the thermal runaway detection is performed on the power battery system according to the current module temperature sampling results of the plurality of modules, the battery cell temperature prediction results and the preset thermal runaway condition set to obtain the thermal runaway detection result, which specifically includes: According to the current module temperature sampling results of the plurality of modules, determining whether the power battery system meets the conditions in the first condition set, and obtaining the first diagnosis result; According to the current module temperature sampling results of the plurality of modules and the battery cell temperature prediction results, determining whether the power battery system meets the conditions in the second condition set, and obtaining the second diagnosis result; The controlling the state of the battery management system according to the thermal runaway detection result specifically includes: Determining, according to the first diagnostic result and the second diagnostic result, whether the power battery system satisfies at least one condition in the first condition set and at least one condition in the second condition set; When it is determined that the power battery system does not satisfy any condition in the first condition set and does not satisfy any condition in the second condition set, controlling the power battery system to operate normally; When it is determined that the power battery system satisfies at least one condition in the first condition set and satisfies at least one condition in the second condition set, controlling the power battery system to enter a safe state; When it is determined that the power battery system satisfies only at least one condition in the first condition set or only satisfies at least one condition in the second condition set, controlling the power battery system to perform power degradation; The first condition set includes thermal runaway conditions at the module level and the battery pack level; the second condition set includes thermal runaway conditions at the module level and the cell level.

2. The temperature monitoring method of the power battery system according to claim 1, characterized in that: The battery management system further includes a slave controller; the slave controller includes a single chip microcomputer, a plurality of temperature sensors and a plurality of temperature acquisition circuits connected to each of the temperature sensors in a one-to-one correspondence; the plurality of temperature sensors are arranged in a plurality of modules in the power battery system, and the number of temperature sensors arranged in each of the modules is at least two; the single chip microcomputer is used to control the plurality of temperature acquisition circuits to acquire signals from the plurality of temperature sensors, and to perform acquisition completion status diagnosis and electrical diagnosis on the plurality of temperature acquisition circuits, so as to obtain initial temperature sampling results, acquisition completion status diagnosis results and electrical diagnosis results of the plurality of modules and send them to the main controller; The obtaining of current module temperature sampling results of several modules in the power battery system specifically includes: Receiving initial temperature sampling results, collection completion status diagnosis results and electrical diagnosis results of the plurality of modules sent by the slave controller; Determining whether initial temperature sampling results of the plurality of modules are valid according to the temperature sampling completion status diagnosis results and electrical diagnosis results of the plurality of modules; For each of the modules, if the initial temperature sampling result of the module is valid, the initial temperature sampling result of the module is used as the current module temperature sampling result of the module; if the initial temperature sampling result of the module is invalid, the alternative values ​​of each temperature sampling value in the initial temperature sampling result of the module are obtained, and the alternative values ​​of each temperature sampling value are used as the current module temperature sampling result of the module.

3. The temperature monitoring method of the power battery system according to claim 2, characterized in that: The method further comprises: A fault detection is performed on the communication status between the master controller and the slave controller, and when a communication fault is detected, the power battery system is controlled to enter a safe state.

4. The temperature monitoring method of the power battery system according to claim 1, characterized in that: The step of predicting the internal temperatures of the battery cells in the plurality of modules according to the current module temperature sampling results of the plurality of modules to obtain the battery cell temperature prediction results of the plurality of modules specifically includes: Obtaining a moving average current of the power battery system within a preset time before a current moment; Based on the corresponding relationship between the current magnitude and the temperature correction amount, the current temperature correction amount is determined according to the current moving average value; The current module temperature sampling results of the plurality of modules are corrected according to the current temperature correction amount to obtain the battery cell temperature prediction results of the plurality of modules.

5. The temperature monitoring method of the power battery system according to claim 1, characterized in that: The current module temperature sampling result includes at least two temperature sampling values; The first condition set specifically includes at least one of the following conditions: The maximum temperature sampling value of at least one module in the power battery system exceeds a preset first temperature range; The sampling temperature change rate of at least one module in the power battery system exceeds a preset first change rate threshold; wherein the sampling temperature change rate of each module is calculated based on the current module temperature sampling result and historical temperature sampling result data of the module; The maximum temperature sample value in the power battery system exceeds a preset first temperature threshold; The difference between the highest temperature sampling value and the lowest temperature sampling value of at least one module in the power battery system exceeds a preset temperature difference threshold.

6. The temperature monitoring method of the power battery system according to claim 5, characterized in that: The second condition set specifically includes at least one of the following conditions: The maximum temperature sampling value of at least one module in the power battery system exceeds a preset second temperature range; The predicted temperature change rate of the battery cells of at least one module in the power battery system exceeds a preset second change rate threshold; wherein the predicted temperature change rate of the battery cells of each module is calculated based on the battery cell temperature prediction result of the module and the historical battery cell temperature prediction result data; The predicted value of the highest battery cell temperature in the power battery system exceeds a preset second temperature threshold.

7. The temperature monitoring method of the power battery system according to claim 1, characterized in that: When it is determined that the power battery system satisfies only at least one condition in the first condition set or only satisfies at least one condition in the second condition set, after controlling the power battery system to perform power degradation, the method further includes: Repeat the steps of obtaining the current module temperature sampling results of the plurality of modules to obtaining the thermal runaway detection results until one of the stop execution conditions is met, and judge whether the power battery system meets at least one condition in the first condition set and at least one condition in the second condition set according to the current first diagnosis result and the current second diagnosis result; wherein the stop execution condition at least includes that the time for repeatedly performing the above steps reaches a preset time threshold; If it is determined that the power battery system does not satisfy any condition in the first condition set and does not satisfy any condition in the second condition set, the power battery system is controlled to operate normally; otherwise, the power battery system is controlled to enter a safe state.

8. The temperature monitoring method of the power battery system according to claim 5, characterized in that: The main controller includes at least two cores; The step of determining whether the power battery system satisfies a condition in the first condition set according to the current module temperature sampling results of the plurality of modules, and obtaining the first diagnosis result is performed by the first core of the main controller; The step of predicting the internal temperatures of the battery cells in the several modules based on the current module temperature sampling results of the several modules to obtain the battery cell temperature prediction results of the several modules, and the step of judging whether the power battery system satisfies the conditions in the second condition set based on the current module temperature sampling results and the battery cell temperature prediction results of the several modules to obtain the second diagnostic result are executed by the second core of the main controller.

9. The temperature monitoring method of the power battery system according to claim 8, characterized in that: Also includes the steps: Data flow monitoring and program flow monitoring are performed on the first core and the second core, and when it is monitored that a data flow abnormality or a program flow abnormality occurs in one of the first core and the second core, the power battery system is controlled to enter a safe state.

10. A battery management system, characterized in that: Including main controller; Wherein, the main controller specifically includes: A sampling module, used to obtain current module temperature sampling results of several modules in the power battery system; A prediction module, used to predict the internal temperature of the battery cells in the plurality of modules according to the current module temperature sampling results of the plurality of modules, so as to obtain the battery cell temperature prediction results of the plurality of modules; A detection module, configured to perform thermal runaway detection on the power battery system according to current module temperature sampling results of the plurality of modules, battery cell temperature prediction results and a preset thermal runaway condition set, to obtain a thermal runaway detection result; A control module, used for controlling the state of the battery management system according to the thermal runaway detection result; The thermal runaway condition set includes a first condition set and a second condition set; The thermal runaway detection result includes a first diagnosis result and a second diagnosis result; The detection module is specifically used to: determine whether the power battery system meets the conditions in the first condition set according to the current module temperature sampling results of the plurality of modules, and obtain the first diagnosis result; determine whether the power battery system meets the conditions in the second condition set according to the current module temperature sampling results of the plurality of modules and the battery cell temperature prediction results, and obtain the second diagnosis result; The control module is specifically used to: determine whether the power battery system satisfies at least one condition in the first condition set and at least one condition in the second condition set according to the first diagnostic result and the second diagnostic result; when it is determined that the power battery system does not satisfy any condition in the first condition set and does not satisfy any condition in the second condition set, control the power battery system to operate normally; when it is determined that the power battery system satisfies at least one condition in the first condition set and satisfies at least one condition in the second condition set, control the power battery system to enter a safe state; when it is determined that the power battery system only satisfies at least one condition in the first condition set or only satisfies at least one condition in the second condition set, control the power battery system to perform power degradation; The first condition set includes thermal runaway conditions at the module level and the battery pack level; the second condition set includes thermal runaway conditions at the module level and the cell level.

11. A battery management system, characterized in that: It includes a main controller; the main controller includes a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, and when the processor executes the computer program, it implements the temperature monitoring method of the power battery system as described in any one of claims 1 to 9.

12. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a stored computer program, wherein when the computer program is executed, the device where the computer-readable storage medium is located is controlled to execute the temperature monitoring method for the power battery system according to any one of claims 1 to 9.

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