A lithium precipitation identification method and device for a lithium battery for a vehicle

Abstract

The application provides a lithium precipitation identification method and device for vehicle lithium battery, belonging to the technical field of lithium precipitation identification. When the battery management system identifies that the vehicle lithium battery meets the lithium precipitation identification condition, the lithium precipitation detection mode is started and a constant small rate discharge request is generated and sent to the vehicle energy distribution system. The vehicle energy distribution system maintains the discharge of the vehicle lithium battery within the temperature range through energy distribution, and the lithium precipitation characteristic parameters of the vehicle lithium battery are calculated in real time and uploaded to the cloud platform. The cloud platform calculates the lithium precipitation capacity of the vehicle lithium battery combined with historical data. Thus, the power source advantage of the hybrid electric vehicle is fully utilized, the vehicle lithium battery is discharged at a constant small rate under suitable temperature, the lithium precipitation characteristic parameters are obtained through the battery management system without adding sensors; and the vehicle cloud cooperation mode is adopted to analyze the lithium precipitation characteristic parameters in real time, confirm the lithium precipitation condition and respond, so as to ensure the stable and safe operation of the vehicle.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium precipitation identification, in particular to a lithium precipitation identification method and device for vehicle lithium battery. BACKGROUND

[0002] When the lithium ion battery of an electric vehicle is charged at low temperature or fast charged, a lithium precipitation side reaction is likely to occur at the interface between the negative electrode and the electrolyte, lithium dendrites are precipitated, the uncontrolled growth of lithium dendrites is accompanied by a huge volume change and the formation of dead lithium, which causes the rapid attenuation of battery capacity, reduces the driving range of the vehicle, and the growing lithium dendrites may pierce the separator, causing internal short circuit of the battery and increasing the risk of thermal runaway.

[0003] Among them, according to whether the battery needs to be disassembled, the lithium precipitation identification method can be divided into invasive diagnosis method and non-invasive lithium precipitation diagnosis method. The invasive method mainly includes optical imaging method, electronic imaging method, mass spectrometry titration method and titration-gas chromatography method, etc., but since the invasive lithium precipitation identification method needs to disassemble the battery, it is not suitable for battery application. Common non-invasive methods include excitation model method, coulomb efficiency method, voltage curve method, reference electrode method, electrochemical impedance method and neutron diffraction method, etc., among which the neutron diffraction method relies on large and expensive equipment, which is difficult to integrate into the BMS; the model driven method requires the BMS to have sufficient computing power to support the real-time calculation of mechanism model parameter update and state observer; the coulomb efficiency method requires the BMS to have high current sampling accuracy, and specific working conditions of full charge and full discharge to ensure the accurate calculation of coulomb efficiency; the reference electrode method requires the lithium battery to be implanted with a reference electrode, which is not suitable for current commercial batteries; the electrochemical impedance method mainly uses intermittent charging method and DEIS method to measure the impedance information of the lithium battery, among which the intermittent time of the intermittent charging method will affect the charging speed of the battery, and there is no general empirical formula for setting the length of the intermittent time, and the DEIS method needs to use the alternating current signal emitted by the alternating current tester to measure the impedance information during the charging process of the battery, which is currently difficult to be directly applied in the BMS; the lithium precipitation characteristics required by the voltage curve method can be directly extracted from the parameters detected by the BMS, so its implementability is the highest.

[0004] However, the current battery management system does not have the function of identifying lithium precipitation. SUMMARY

[0005] Therefore, the purpose of the present application is to provide a lithium precipitation identification method and device for vehicle lithium battery, which can accurately detect and respond to lithium precipitation of vehicle lithium battery of hybrid electric vehicle, and ensure stable and safe operation of the vehicle.

[0006] In a first aspect, the application provides a lithium precipitation identification method for vehicle lithium battery, which is applied to a hybrid electric vehicle. The hybrid electric vehicle comprises a vehicle energy distribution system, a battery management system and a cloud platform. The battery management system comprises a lithium precipitation detection mode setting module, a power system power control module, a lithium precipitation characteristic parameter calculation module, a lithium precipitation parameter cloud platform interaction module and a lithium precipitation coping module. The identification method comprises the following steps:

[0007] The lithium precipitation identification conditions of the vehicle lithium battery are set based on the lithium precipitation detection mode setting module, and the lithium precipitation detection mode is started when the vehicle lithium battery meets the lithium precipitation identification conditions identified by the battery management system. The lithium precipitation identification conditions comprise a temperature range of the vehicle lithium battery after being fully charged.

[0008] A constant small rate discharge request is generated based on the power system power control module and sent to the vehicle energy distribution system. The vehicle energy distribution system maintains the discharge of the vehicle lithium battery in the temperature range through energy distribution according to the constant small rate discharge request.

[0009] The lithium precipitation characteristic parameters of the vehicle lithium battery during constant small rate discharge are calculated in real time based on the lithium precipitation characteristic parameter calculation module and uploaded to the cloud platform through the lithium precipitation parameter cloud platform interaction module. The lithium precipitation capacity of the vehicle lithium battery is calculated by the cloud platform according to the received lithium precipitation characteristic parameters and combined with historical data, and is issued to the battery management system.

[0010] In a possible implementation, the lithium precipitation detection mode is started when the vehicle lithium battery meets the lithium precipitation identification conditions identified by the battery management system, which comprises the following steps:

[0011] When the vehicle lithium battery meets the lithium precipitation identification conditions identified by the battery management system, a lithium precipitation detection mode start prompt is generated.

[0012] If a lithium precipitation detection mode start acceptance instruction is received within a set time, the lithium precipitation detection mode is started. If no lithium precipitation detection mode start acceptance instruction is received, the lithium precipitation detection mode is abandoned.

[0013] In a possible implementation, the discharge of the vehicle lithium battery in the temperature range by the vehicle energy distribution system according to the constant small rate discharge request through energy distribution comprises the following steps:

[0014] The working state of the vehicle energy distribution system is monitored in real time based on the battery management system.

[0015] If the working state of the vehicle energy distribution system is abnormal, the lithium precipitation detection mode is stopped.

[0016] In a possible implementation, the lithium precipitation characteristic parameter is a minimum value of a battery voltage change value per unit discharge capacity in a time period; and the calculation of the lithium precipitation capacity of the vehicle lithium battery by the cloud platform according to the received lithium precipitation characteristic parameter and in combination with historical data comprises the following steps:

[0017] constructing a current differential voltage curve according to the received lithium precipitation characteristic parameter;

[0018] judging whether the vehicle lithium battery has lithium precipitation according to a change trend of the current differential voltage curve;

[0019] if it is judged that the vehicle lithium battery has lithium precipitation, obtaining a first discharge capacity corresponding to a first trough position of the current differential voltage curve, and obtaining a second discharge capacity corresponding to a first trough position of a historical differential voltage curve through historical data;

[0020] calculating a difference between the first discharge capacity and the second discharge capacity to obtain the lithium precipitation capacity in the time period.

[0021] In a possible implementation, the judging whether the vehicle lithium battery has lithium precipitation according to the change trend of the current differential voltage curve comprises the following steps:

[0022] if the current differential voltage curve is monotonically increasing, it is judged that the vehicle lithium battery does not have lithium precipitation;

[0023] if the current differential voltage curve is first increasing, then decreasing, and then increasing, it is judged that the vehicle lithium battery has lithium precipitation.

[0024] In a possible implementation, the method further comprises the following steps:

[0025] if it is judged that the vehicle lithium battery has lithium precipitation, determining a maximum lithium precipitation capacity from lithium precipitation capacities of all vehicle lithium batteries;

[0026] adjusting a charging current based on the maximum lithium precipitation capacity and a rated capacity and a charging rate of the vehicle lithium battery.

[0027] In a possible implementation, the temperature range of the vehicle lithium battery after being fully charged is set to 10-35℃.

[0028] In a second aspect, the application provides a vehicle lithium battery lithium precipitation identification device, which is applied to a hybrid electric vehicle, the hybrid electric vehicle comprising a vehicle energy distribution system, a battery management system and a cloud platform, the battery management system comprising a lithium precipitation detection mode setting module, a power system power control module, a lithium precipitation characteristic parameter calculation module, a lithium precipitation parameter cloud platform interaction module and a lithium precipitation coping module; the identification device comprises:

[0029] The setting module is configured to set a lithium precipitation identification condition of the vehicle lithium battery based on the lithium precipitation detection mode setting module, and to start the lithium precipitation detection mode when the battery management system identifies that the vehicle lithium battery meets the lithium precipitation identification condition; wherein the lithium precipitation identification condition comprises a temperature range of the vehicle lithium battery after being fully charged.

[0030] The control module is configured to generate a constant small rate discharge request based on the power system power control module, and to send the constant small rate discharge request to the whole vehicle energy distribution system, so that the whole vehicle energy distribution system discharges the vehicle lithium battery within the temperature range through energy distribution according to the constant small rate discharge request.

[0031] The calculation module is configured to calculate the lithium precipitation characteristic parameter of the vehicle lithium battery in constant small rate discharge in real time based on the lithium precipitation characteristic parameter calculation module, and to upload the lithium precipitation characteristic parameter to the cloud platform through the lithium precipitation parameter cloud platform interaction module, so that the cloud platform calculates the lithium precipitation capacity of the vehicle lithium battery according to the received lithium precipitation characteristic parameter and historical data, and sends the lithium precipitation capacity to the battery management system.

[0032] In a third aspect, the present application provides an electronic device, comprising a processor, a memory and a bus, the memory stores machine readable instructions executable by the processor, when the electronic device is running, the processor and the memory communicate through the bus, and the machine readable instructions are executed by the processor to perform the steps of the vehicle lithium battery lithium precipitation identification method according to the first aspect.

[0033] In a fourth aspect, the present application provides a computer readable storage medium, the computer readable storage medium stores a computer program, when the computer program is run by a processor, the steps of the vehicle lithium battery lithium precipitation identification method according to the first aspect are executed.

[0034] The embodiment provides a lithium precipitation identification method and device for vehicle lithium battery, based on the lithium precipitation detection mode setting module, the lithium precipitation identification working condition of the vehicle lithium battery is set, and when the battery management system identifies that the vehicle lithium battery meets the lithium precipitation identification working condition, the lithium precipitation detection mode is started; based on the power system power control module, a constant small rate discharge request is generated and sent to the whole vehicle energy distribution system, and the whole vehicle energy distribution system maintains the discharge of the vehicle lithium battery in the temperature range according to the constant small rate discharge request; based on the lithium precipitation characteristic parameter calculation module, the lithium precipitation characteristic parameters of the vehicle lithium battery during constant small rate discharge are calculated in real time, and the lithium precipitation parameter cloud platform interaction module is uploaded to the cloud platform, and the cloud platform calculates the lithium precipitation capacity of the vehicle lithium battery according to the received lithium precipitation characteristic parameters and combines historical data, and issues to the battery management system. On the one hand, the power source advantage of the hybrid electric vehicle is fully utilized, the constant small rate discharge of the vehicle lithium battery is realized through the energy distribution of the whole vehicle energy distribution system, the lithium precipitation characteristic parameters are obtained through the battery management system without increasing additional sensors, and the cost is reduced; on the other hand, the vehicle cloud cooperation mode is adopted, the lithium precipitation characteristic parameters are analyzed in real time, the lithium precipitation situation is confirmed and coped with, so that the stable and safe operation of the vehicle is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0036] Figure 1 The flowchart of the lithium precipitation identification method for vehicle lithium battery in an embodiment of the present application;

[0037] Figure 2 The connection diagram among the whole vehicle energy distribution system, the battery management system and the cloud platform in an embodiment of the present application;

[0038] Figure 3 The schematic diagram of the current differential voltage curve in an embodiment of the present application;

[0039] Figure 4 The structural block diagram of the lithium precipitation identification device for vehicle lithium battery in an embodiment of the present application;

[0040] Figure 5 The structural block diagram of the electronic device in an embodiment of the present application. DETAILED DESCRIPTION

[0041] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the following will be combined with the accompanying drawings for the embodiments of the present application to make a clear and complete description of the technical solutions in the embodiments of the present application. It should be understood that the accompanying drawings in the present application are only for the purpose of illustration and description, and are not used to limit the protection scope of the present application. In addition, it should be understood that the schematic drawings are not drawn according to the actual proportions. The flowcharts used in the present application show the operations implemented according to some embodiments of the present application. It should be understood that the operations of the flowcharts can not be implemented in sequence, and the steps without logical context relationship can be reversed in sequence or implemented simultaneously. In addition, one or more other operations can be added to the flowcharts or one or more operations can be removed from the flowcharts under the guidance of the content of the present application.

[0042] In addition, the described embodiments are only some of the embodiments of the present application, not all the embodiments. The components of the embodiments of the present application described and indicated in the accompanying drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0043] It should be noted that the term "comprising" will be used in the embodiments of the present application to indicate the presence of the features declared thereafter, but does not exclude the addition of other features.

[0044] Based on the technical problems proposed in the background, the present application provides a lithium precipitation identification method and device for vehicle lithium battery, which can accurately detect and respond to lithium precipitation of vehicle lithium battery of hybrid electric vehicle, and ensure stable and safe operation of the vehicle.

[0045] Referring to the description of the accompanying drawings Figure 1 and the description of the accompanying drawings Figure 2 In an embodiment, the present application provides a lithium precipitation identification method for vehicle lithium battery, applied to a hybrid electric vehicle, wherein the hybrid electric vehicle comprises a whole vehicle energy distribution system, a battery management system and a cloud platform, the battery management system comprises a lithium precipitation detection mode setting module, a power system power control module, a lithium precipitation characteristic parameter calculation module, a lithium precipitation parameter cloud platform interaction module and a lithium precipitation response module; the identification method comprises the following steps:

[0046] S1, based on the lithium precipitation detection mode setting module, set the lithium precipitation identification working condition of the vehicle lithium battery, and when the battery management system identifies that the vehicle lithium battery meets the lithium precipitation identification working condition, start the lithium precipitation detection mode; wherein the lithium precipitation identification working condition comprises the temperature range of the vehicle lithium battery after being fully charged;

[0047] S2, generating a constant small rate discharge request based on the power system power control module and sending to the vehicle energy distribution system, and the vehicle energy distribution system discharges the vehicle lithium battery within the temperature range through energy distribution according to the constant small rate discharge request;

[0048] S3, calculating the lithium precipitation characteristic parameter of the vehicle lithium battery in constant small rate discharge in real time based on the lithium precipitation characteristic parameter calculation module, and uploading to the cloud platform through the lithium precipitation parameter cloud platform interaction module, and the cloud platform calculates the lithium precipitation capacity of the vehicle lithium battery according to the received lithium precipitation characteristic parameter and combines historical data, and issues to the battery management system.

[0049] Specifically, in step S1, if the battery management system identifies that the vehicle lithium battery of the hybrid electric vehicle is just fully charged, and the temperature of the vehicle lithium battery is suitable, a lithium precipitation detection mode opening prompt is generated, that is, the driver is prompted to open the lithium precipitation detection mode; if the lithium precipitation detection mode opening acceptance instruction received within the set time opens the lithium precipitation detection mode; if the lithium precipitation detection mode opening acceptance instruction is not received within the set time, the lithium precipitation detection mode is abandoned.

[0050] For example, the set temperature of the vehicle lithium battery is 10℃-35℃, and the set prompt time is 2min. In an embodiment, if the vehicle lithium battery of the hybrid electric vehicle is just fully charged and the temperature of the vehicle lithium battery is 25℃, the battery management system confirms that the vehicle lithium battery meets the lithium precipitation identification condition, sends a prompt to the driver to open the lithium precipitation detection mode, and if the driver agrees to open the lithium precipitation detection mode within 2min, step S2 is executed, and if the driver does not agree to open the lithium precipitation detection mode within 2min, it is considered that the lithium precipitation detection mode is refused to be opened this time; in another embodiment, if the vehicle lithium battery of the hybrid electric vehicle is just fully charged and the temperature of the vehicle lithium battery is 0℃, the battery management system confirms that the vehicle lithium battery does not meet the lithium precipitation identification condition, and does not send a prompt to the driver to open the lithium precipitation detection mode.

[0051] In step S2, after opening the lithium precipitation detection mode, the power system power control module of the battery management system sets a constant small rate discharge request according to the current temperature of the vehicle lithium battery and sends it to the vehicle energy distribution system. The vehicle energy distribution system adjusts the energy distribution of the vehicle high and low voltage devices to ensure that the vehicle lithium battery continuously discharges at a constant small rate, for example, the power during the driving and idling process of the hybrid electric vehicle under the lithium precipitation identification condition, and the energy supply of the vehicle high and low voltage electronic devices is provided by the vehicle lithium battery small rate discharge, and the rest is provided by the vehicle energy distribution system coordinated engine, small battery, etc. In addition, the temperature of the thermal management system is adjusted in the lithium precipitation detection mode to ensure that the vehicle lithium battery discharges at a small rate at a suitable temperature.

[0052] It should be noted that the whole vehicle energy distribution system maintains the discharge of the vehicle lithium battery in the temperature range according to the constant small rate discharge request through the energy distribution. The battery management system monitors the working state of the whole vehicle energy distribution system in real time. If the working state of the whole vehicle energy distribution system is abnormal, the lithium analysis detection mode is stopped in time.

[0053] Therefore, the application fully utilizes the advantages of the multiple power sources of the hybrid electric vehicle, and realizes the constant small rate discharge of the vehicle lithium battery and the lithium analysis detection of the vehicle lithium battery through the control of the whole vehicle energy distribution without affecting the normal use of the vehicle.

[0054] In step S3, the battery management system collects the voltage of the vehicle lithium battery in the lithium analysis detection mode in real time during the discharge process, calculates the minimum value of the lithium analysis characteristic parameter dV / dQ (the change value of the battery voltage per unit discharge capacity) of the time interval through the lithium analysis characteristic parameter calculation module, and uploads it to the cloud platform.

[0055] That is, the application does not need to add sensors, but uses the existing sampling and operation resources of the battery management system, which is low in cost and high in practicability.

[0056] Referring to the drawings accompanying the specification Figure 3 After receiving the lithium analysis characteristic parameter dV / dQ of the lithium battery uploaded by the battery management system, the cloud platform constructs the current differential voltage curve of the discharge process (the horizontal axis is the discharge capacity, and the vertical axis is dV / dQ) after eliminating the abnormal value. If the current differential voltage curve is monotonically increasing, it is confirmed that the vehicle lithium battery does not occur lithium analysis. If the current differential voltage curve is first increasing, then decreasing, and then increasing, it means that the vehicle lithium battery occurs lithium analysis. Moreover, the first trough position in the current differential voltage curve corresponds to the end of the lithium stripping process inside the battery. The discharge capacity at the trough position corresponds to the reversible lithium metal amount in the lithium analysis reaction. Further, combined with the historical data stored in the cloud platform, the discharge capacity corresponding to the first trough position of the historical differential voltage curve is obtained through the historical data. The difference between the two discharge capacities is the decrease of the reversible lithium, that is, the newly added lithium analysis capacity in this stage, and the formula is as follows: lithium analysis capacity = first discharge capacity corresponding to the first trough position of the current differential voltage curve-second discharge capacity corresponding to the first trough position of the historical differential voltage curve.

[0057] In an embodiment, it is assumed that the cloud platform identifies that the first section of the lithium battery pack for the hybrid electric vehicle is in the lithium precipitation detection mode, the discharge capacity corresponding to the first differential voltage trough position of the current differential voltage curve is 10 AH, and the discharge capacity corresponding to the first differential voltage trough position of the historical differential voltage curve is 17 AH; in the second section of the lithium battery pack for the hybrid electric vehicle, the discharge capacity corresponding to the first differential voltage trough position of the current differential voltage curve is 8 AH, and the discharge capacity corresponding to the first differential voltage trough position of the historical differential voltage curve is 13 AH, and the lithium precipitation capacity is: the lithium precipitation capacity of the first section of the lithium battery pack for the hybrid electric vehicle = 17-10 = 7 AH; the lithium precipitation capacity of the second section of the lithium battery pack for the hybrid electric vehicle = 13-8 = 5 AH.

[0058] Therefore, the cloud platform is used to evaluate the lithium precipitation capacity of the lithium battery for the vehicle by using the advantages of high computing power and strong storage capacity of the cloud platform, and the deviation of the lithium precipitation recognition of the battery management system is avoided.

[0059] In addition, in the present application, the cloud platform issues the lithium precipitation condition of the lithium battery and the maximum lithium precipitation capacity of all cells of the battery pack to the battery management system. If lithium precipitation occurs in the lithium battery for the vehicle, the charging rate is reduced under the conditions of fast charging and low-temperature charging to cope with the lithium precipitation. The charging current = charging rate * (rated capacity - maximum lithium precipitation capacity).

[0060] In an embodiment, it is assumed that the rated capacity of the lithium battery for the vehicle is 153 AH, the charging rate under the fast charging condition at 25°C is 2C, the cloud platform informs the battery management system that the lithium battery for the vehicle has occurred lithium precipitation, and the maximum lithium precipitation capacity of the cell is 7 AH, then the charging current = charging rate * (rated capacity - maximum lithium precipitation capacity) = 2 * (153-7) = 292 A; if the cloud platform informs the battery management system that the lithium battery for the vehicle has not occurred lithium precipitation, then the charging current = charging rate * (rated capacity - maximum lithium precipitation capacity) = 2 * (153-0) = 306 A.

[0061] The lithium precipitation identification method for the lithium battery for the vehicle provided in the present application realizes the constant small rate discharge of the lithium battery for the vehicle at a suitable temperature through the confirmation of the lithium precipitation detection mode of the lithium battery for the hybrid electric vehicle, the cooperation of the energy distribution system, the thermal management system and the battery management system. The battery management system calculates the minimum value of dV / dQ in a period of time in real time, uploads the cloud platform, the cloud platform constructs the differential voltage curve of the discharge process, and the discharge capacity corresponding to the first curve trough position is the reversible lithium metal amount in the lithium precipitation reaction. The difference between the capacity corresponding to the trough position of the historical differential voltage curve is the decrease of the reversible lithium, that is, the newly added lithium precipitation capacity. If lithium precipitation is detected, the charging rate under the low-temperature charging condition is reduced to cope with the lithium precipitation, and the stable and safe operation of the hybrid electric vehicle is realized.

[0062] As shown in the accompanying drawings Figure 4As shown, the application also provides a lithium precipitation identification device for vehicle lithium battery, which is applied to a hybrid electric vehicle. The hybrid electric vehicle comprises a whole vehicle energy distribution system, a battery management system and a cloud platform. The battery management system comprises a lithium precipitation detection mode setting module, a power system power control module, a lithium precipitation characteristic parameter calculation module, a lithium precipitation parameter cloud platform interaction module and a lithium precipitation coping module. The identification device comprises:

[0063] The setting module 401 is configured to set a lithium precipitation identification condition for the vehicle lithium battery based on the lithium precipitation detection mode setting module, and start the lithium precipitation detection mode when the battery management system identifies that the vehicle lithium battery meets the lithium precipitation identification condition. The lithium precipitation identification condition comprises a temperature range of the vehicle lithium battery after being fully charged.

[0064] The control module 402 is configured to generate a constant small rate discharge request based on the power system power control module, and send the constant small rate discharge request to the whole vehicle energy distribution system. The whole vehicle energy distribution system maintains the discharge of the vehicle lithium battery in the temperature range through energy distribution according to the constant small rate discharge request.

[0065] The calculation module 403 is configured to calculate the lithium precipitation characteristic parameters of the vehicle lithium battery in constant small rate discharge in real time based on the lithium precipitation characteristic parameter calculation module, and upload the lithium precipitation characteristic parameters to the cloud platform through the lithium precipitation parameter cloud platform interaction module. The cloud platform calculates the lithium precipitation capacity of the vehicle lithium battery according to the received lithium precipitation characteristic parameters and historical data, and sends the lithium precipitation capacity to the battery management system.

[0066] In some embodiments, the setting module 401 starts the lithium precipitation detection mode when the battery management system identifies that the vehicle lithium battery meets the lithium precipitation identification condition, which comprises: generating a lithium precipitation detection mode start prompt when the battery management system identifies that the vehicle lithium battery meets the lithium precipitation identification condition; if a lithium precipitation detection mode start acceptance instruction is received within a set time, starting the lithium precipitation detection mode; if no lithium precipitation detection mode start acceptance instruction is received, giving up starting the lithium precipitation detection mode.

[0067] In some embodiments, the control module 402 maintains the discharge of the vehicle lithium battery in the temperature range through energy distribution by the whole vehicle energy distribution system according to the constant small rate discharge request, which comprises: monitoring the working state of the whole vehicle energy distribution system in real time based on the battery management system; if the working state of the whole vehicle energy distribution system is abnormal, stopping the lithium precipitation detection mode.

[0068] In some embodiments, the lithium precipitation characteristic parameter is the minimum value of the change value of the battery voltage per unit discharge capacity within a time period, and the computing module 403 calculates the lithium precipitation capacity of the vehicle lithium battery according to the received lithium precipitation characteristic parameter and historical data, including: constructing a current differential voltage curve according to the received lithium precipitation characteristic parameter; determining whether the vehicle lithium battery has lithium precipitation according to the change trend of the current differential voltage curve; if it is determined that the vehicle lithium battery has lithium precipitation, obtaining a first discharge capacity corresponding to a first trough position of the current differential voltage curve, and obtaining a second discharge capacity corresponding to a first trough position of a historical differential voltage curve through historical data; calculating the difference between the first discharge capacity and the second discharge capacity to obtain the lithium precipitation capacity within the time period. Wherein, if the current differential voltage curve is monotonically increasing, it is determined that the vehicle lithium battery has not lithium precipitation; if the current differential voltage curve first increases, then decreases, and then increases, it is determined that the vehicle lithium battery has lithium precipitation.

[0069] In some embodiments, the device further comprises:

[0070] The adjusting module is configured to, if it is determined that the vehicle lithium battery has lithium precipitation, determine a maximum lithium precipitation capacity from the lithium precipitation capacities of all vehicle lithium batteries; and adjust the charging current based on the maximum lithium precipitation capacity, and the rated capacity and the charging rate of the vehicle lithium battery.

[0071] The vehicle lithium battery lithium precipitation identification device provided in the present application sets the lithium precipitation identification working condition of the vehicle lithium battery through the setting module based on the lithium precipitation detection mode setting module, and starts the lithium precipitation detection mode when the battery management system identifies that the vehicle lithium battery meets the lithium precipitation identification working condition; the control module generates a constant small rate discharge request based on the power system power control module, and sends it to the vehicle energy distribution system, and the vehicle energy distribution system maintains the discharge of the vehicle lithium battery within the temperature range through energy distribution according to the constant small rate discharge request; the computing module calculates the lithium precipitation characteristic parameter of the vehicle lithium battery in constant small rate discharge in real time based on the lithium precipitation characteristic parameter calculation module, and uploads it to the cloud platform through the lithium precipitation parameter cloud platform interaction module, and the cloud platform calculates the lithium precipitation capacity of the vehicle lithium battery according to the received lithium precipitation characteristic parameter and historical data, and issues it to the battery management system. On the one hand, the power source advantage of the hybrid electric vehicle is fully utilized, the vehicle lithium battery is discharged at a constant small rate under suitable temperature through the energy distribution of the vehicle energy distribution system, the lithium precipitation characteristic parameter is obtained through the battery management system without increasing additional sensors, and the cost is reduced; on the other hand, the vehicle cloud cooperation mode is adopted, the lithium precipitation characteristic parameter is analyzed in real time, the lithium precipitation condition is confirmed and responded, so as to ensure the stable and safe operation of the vehicle.

[0072] Based on the same concept of the present application, the specification Figure 5 As shown in the accompanying drawings, the electronic device 500 provided by the embodiments of the present application includes at least one processor 501, at least one network interface 504 or other user interface 503, a memory 505, and at least one communication bus 502. The communication bus 502 is used to realize the connection and communication between the components. The electronic device 500 can optionally include a user interface 503, including a display (for example, a touch screen, an LCD, a CRT, holographic imaging (Holographic), or a projector, etc.), a keyboard or a clicking device (for example, a mouse, a trackball, a touchpad, or a touch screen, etc.).

[0073] The memory 505 can include read-only memory and random access memory, and provide instructions and data for the processor 501. A part of the memory 505 can also include a non-volatile random access memory (NVRAM).

[0074] In some embodiments, the memory 505 stores the following elements, executable modules or data structures, or a subset of them, or an extended set of them:

[0075] The operating system 5051 includes various system programs, used to realize various basic services and process hardware-based tasks;

[0076] The application program module 5052 includes various application programs, such as a desktop (launcher), a media player (MediaPlayer), a browser (Browser), etc., used to realize various application services.

[0077] In the embodiments of the present application, the processor 501 is used to execute the steps in the method for identifying lithium precipitation of a vehicle lithium battery by calling the programs or instructions stored in the memory 505, which can accurately detect and respond to lithium precipitation of a vehicle lithium battery of a hybrid electric vehicle, and ensure stable and safe operation of the vehicle.

[0078] The present application also provides a computer readable storage medium having a computer program stored thereon, which is executed by a processor to perform the steps in the method for identifying lithium precipitation of a vehicle lithium battery.

[0079] Specifically, the storage medium can be a general storage medium, such as a mobile disk, a hard disk, etc., and the computer program stored on the storage medium can be executed to perform the method for identifying lithium precipitation of a vehicle lithium battery.

[0080] In the embodiments provided by the present application, it should be understood that the disclosed apparatus and method can be implemented in other manners. The embodiments described above are merely exemplary, for example, the division of units is only a logical function division, and there can be another division manner in actual implementation; for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections between different units, or the among different units, can be indirect couplings or communication connections through some interfaces, communication interfaces, or a combination of physical or logical interfaces.

[0081] The unit described as a separate component can or can not be physically separate, and the component displayed as a unit can or can not be a physical unit, that is, can be located in one place, or can be distributed on a plurality of network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiments of the present application.

[0082] In addition, each functional unit in the embodiments provided by the present application can be integrated in a processing unit, or each unit can exist physically as a separate unit, or two or more units can be integrated in one unit.

[0083] If the function is implemented in the form of a service function unit and sold or used as an independent product, it can be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the present application essentially or the part that makes a contribution to the prior art, or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium, and includes a number of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods in the various embodiments of the present application. The foregoing storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), magnetic disk or optical disk, and various other media that can store program codes.

[0084] Finally, it should be noted that the above examples are merely specific embodiments of the present application, and are used to illustrate the technical solutions of the present application, but not to limit the same. The protection scope of the present application is not limited thereto. Although the present application has been described in detail with reference to the foregoing examples, it should be understood by those skilled in the art that any person skilled in the art can make modifications or easily think of changes to the technical solutions recorded in the foregoing examples, or make equivalent replacements to some of the technical features, within the technical scope disclosed by the present application. The modifications, changes or replacements do not make the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application. All of them should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for identifying lithium precipitation of a lithium battery for vehicle, characterized by, The application is applied to a hybrid electric vehicle, the hybrid electric vehicle includes a vehicle energy distribution system, a battery management system and a cloud platform, the battery management system includes a lithium precipitation detection mode setting module, a power system power control module, a lithium precipitation characteristic parameter calculation module, a lithium precipitation parameter cloud platform interaction module and a lithium precipitation coping module; the identification method includes the following steps: Based on the lithium precipitation detection mode setting module, the lithium precipitation identification working condition of the vehicle lithium battery is set, and when the battery management system identifies that the vehicle lithium battery meets the lithium precipitation identification working condition, the lithium precipitation detection mode is started; wherein the lithium precipitation identification working condition includes the temperature range of the vehicle lithium battery after being fully charged; Based on the power system power control module, a constant small rate discharge request is generated and sent to the vehicle energy distribution system, and the vehicle energy distribution system maintains the discharge of the vehicle lithium battery in the temperature range through energy distribution according to the constant small rate discharge request; Based on the lithium precipitation characteristic parameter calculation module, the lithium precipitation characteristic parameters of the vehicle lithium battery during constant small rate discharge are calculated in real time, and uploaded to the cloud platform through the lithium precipitation parameter cloud platform interaction module; the cloud platform calculates the lithium precipitation capacity of the vehicle lithium battery according to the received lithium precipitation characteristic parameters and historical data, and issues to the battery management system; wherein the lithium precipitation characteristic parameter is the minimum value of the battery voltage change value per unit discharge capacity in a time period; the cloud platform calculates the lithium precipitation capacity of the vehicle lithium battery according to the received lithium precipitation characteristic parameters and historical data, including the following steps: constructing the current differential voltage curve according to the received lithium precipitation characteristic parameters; judging whether the vehicle lithium battery has lithium precipitation according to the change trend of the current differential voltage curve; if it is judged that the vehicle lithium battery has lithium precipitation, the first discharge capacity corresponding to the first trough position of the current differential voltage curve is obtained, and the second discharge capacity corresponding to the first trough position of the historical differential voltage curve is obtained through historical data; the difference between the first discharge capacity and the second discharge capacity is calculated to obtain the lithium precipitation capacity in the time period; wherein if the current differential voltage curve is monotonically increasing, it is judged that the vehicle lithium battery has not lithium precipitation; if the current differential voltage curve first increases, then decreases, and then increases, it is judged that the vehicle lithium battery has lithium precipitation. 2.The lithium precipitation identification method for vehicle lithium battery according to claim 1, characterized in that, When the battery management system identifies that the vehicle lithium battery meets the lithium precipitation identification working condition, the lithium precipitation detection mode is started, including the following steps: When the battery management system identifies that the vehicle lithium battery meets the lithium precipitation identification working condition, a lithium precipitation detection mode starting prompt is generated; If the received lithium precipitation detection mode starting acceptance instruction is received within the set time, the lithium precipitation detection mode is started; if no lithium precipitation detection mode starting acceptance instruction is received, the lithium precipitation detection mode is abandoned. 3.The method according to claim 2, wherein, Based on the battery management system, the working state of the vehicle energy distribution system is monitored in real time; ​ If the working state of the whole vehicle energy distribution system is abnormal, stop the lithium precipitation detection mode.

4. The lithium precipitation identification method for a vehicle lithium battery according to claim 3, characterized in that, The method further comprises the following steps: If it is determined that lithium precipitation occurs in the vehicle lithium battery, the maximum lithium precipitation capacity is determined from the lithium precipitation capacities of all vehicle lithium batteries. The charging current is adjusted based on the maximum lithium precipitation capacity, and the rated capacity and charging rate of the vehicle lithium battery.

5. The lithium precipitation identification method for a vehicle lithium battery according to claim 4, characterized in that, Wherein, The temperature range of the vehicle lithium battery after being fully charged is set to 10℃-35℃.

6. A lithium precipitation identification device for a lithium battery for a vehicle, characterized by, The application is applied to a hybrid electric vehicle, which comprises a whole vehicle energy distribution system, a battery management system and a cloud platform. The battery management system comprises a lithium precipitation detection mode setting module, a power system power control module, a lithium precipitation characteristic parameter calculation module, a lithium precipitation parameter cloud platform interaction module and a lithium precipitation coping module. The identification device comprises: The setting module is used to set the lithium precipitation identification working condition of the vehicle lithium battery based on the lithium precipitation detection mode setting module, and to start the lithium precipitation detection mode when the battery management system identifies that the vehicle lithium battery meets the lithium precipitation identification working condition. The lithium precipitation identification working condition includes the temperature range of the vehicle lithium battery after being fully charged. The control module is used to generate a constant small rate discharge request based on the power system power control module, and send it to the whole vehicle energy distribution system. The whole vehicle energy distribution system maintains the discharge of the vehicle lithium battery within the temperature range through energy distribution according to the constant small rate discharge request. The calculation module is used to calculate the lithium precipitation characteristic parameters of the vehicle lithium battery in constant small rate discharge in real time based on the lithium precipitation characteristic parameter calculation module, and upload them to the cloud platform through the lithium precipitation parameter cloud platform interaction module. The cloud platform calculates the lithium precipitation capacity of the vehicle lithium battery according to the received lithium precipitation characteristic parameters and historical data, and sends it to the battery management system. The lithium precipitation characteristic parameters are the minimum values of the battery voltage change values per unit discharge capacity within a period of time. The cloud platform calculates the lithium precipitation capacity of the vehicle lithium battery according to the received lithium precipitation characteristic parameters and historical data, which comprises the following steps: constructing the current differential voltage curve according to the received lithium precipitation characteristic parameters; determining whether the vehicle lithium battery has lithium precipitation according to the change trend of the current differential voltage curve; if it is determined that the vehicle lithium battery has lithium precipitation, obtaining the first discharge capacity corresponding to the first trough position of the current differential voltage curve, and obtaining the second discharge capacity corresponding to the first trough position of the historical differential voltage curve through historical data; calculating the difference between the first discharge capacity and the second discharge capacity to obtain the lithium precipitation capacity within the period of time; if the current differential voltage curve is monotonically increasing, it is determined that the vehicle lithium battery has not lithium precipitation; if the current differential voltage curve first increases, then decreases, and then increases, it is determined that the vehicle lithium battery has lithium precipitation.

7. An electronic device, comprising: It comprises: A processor, a memory and a bus, the memory stores machine readable instructions executable by the processor, when the electronic device is running, the processor communicates with the memory through the bus, the machine readable instructions are executed by the processor to execute the steps of the lithium precipitation identification method for vehicle lithium battery as claimed in any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that, A computer readable storage medium stores a computer program, when the computer program is run by the processor, the steps of the lithium precipitation identification method for vehicle lithium battery as claimed in any one of claims 1 to 5 are executed.

Images