Discharge lower limit determination method and device of battery system, equipment, medium and product

Abstract

The invention relates to the technical field of vehicle batteries, in particular to a discharge lower limit determination method, device and equipment of a battery system, a medium and a product, and the method comprises the following steps: obtaining the current environment temperature of the battery system and the whole vehicle demand power when a vehicle is in a discharge working condition at the current environment temperature; determining a temperature interval in which the current environment temperature is located, and determining a target SOC lower limit of the battery system according to the temperature interval in which the current environment temperature is located; and determining a pre-action starting voltage and a pre-action ending voltage according to the target SOC lower limit and / or the vehicle demand power, so as to obtain a discharge lower limit determination result of the battery system according to the target SOC lower limit, the pre-action starting voltage and the pre-action ending voltage. Therefore, the problem that the endurance attenuation of the vehicle battery is too fast due to over-discharge or under-voltage of the battery in the prior art is solved, the available endurance mileage of the vehicle battery is increased, and the safety of the battery is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicle battery, and in particular to a battery system discharge lower limit determination method, device, equipment, medium and product. BACKGROUND

[0002] In the development process of a new energy vehicle project, the amount of battery system discharge is an important evaluation index. The battery discharge amount at different temperatures will be reflected as the vehicle driving range at different temperatures, which is an important reference index for users to evaluate the low temperature capability of the vehicle.

[0003] In related technologies, the battery system discharge cutoff condition is generally controlled by controlling the voltage of the single battery cell. Usually, in order to maximize the battery capacity, the cutoff voltage for stopping discharge is set as the lower limit of the available voltage.

[0004] However, the related art does not comprehensively consider the control of the battery SOC and the battery voltage on the battery discharge lower limit, which is prone to cause battery over-discharge or under-voltage problems, and needs to be solved urgently. SUMMARY

[0005] The present application provides a battery system discharge lower limit determination method, device, equipment, medium and product to solve the problem of rapid battery endurance decay caused by battery over-discharge or under-voltage in related technologies, improve the available endurance mileage of the vehicle battery, and improve the safety of the battery.

[0006] The first aspect of the present application provides a battery system discharge lower limit determination method, comprising the following steps: obtaining the current environmental temperature of the battery system and the vehicle demand power when the vehicle is in a discharge working condition at the current environmental temperature; determining the temperature interval in which the current environmental temperature is located, and determining the target SOC lower limit of the battery system according to the temperature interval in which the current environmental temperature is located; determining the pre-action start voltage and the pre-action end voltage according to the target SOC lower limit and / or the vehicle demand power, so as to obtain the discharge lower limit determination result of the battery system according to the target SOC lower limit, the pre-action start voltage and the pre-action end voltage.

[0007] Further, in some embodiments, the determination of the temperature interval in which the current environmental temperature is located, and the determination of the target SOC lower limit of the battery system according to the temperature interval in which the current environmental temperature is located, comprises: judging whether the current environmental temperature is in a preset normal temperature interval; if the current environmental temperature is in the preset normal temperature interval, obtaining the vehicle demand power when the vehicle is in a discharge working condition and the SOC accuracy of the battery system; determining the target SOC lower limit according to the smaller value of the vehicle demand power and the SOC accuracy.

[0008] Further, in some embodiments, the determining the pre-action start voltage and the pre-action end voltage according to the target SOC lower limit and / or the vehicle demand power comprises: determining a first voltage corresponding to the target SOC lower limit, and obtaining the pre-action start voltage according to a difference between the first voltage and a first preset voltage; determining a real SOC lower limit of the battery system according to the current environmental temperature, and obtaining the pre-action end voltage according to a sum of a second voltage corresponding to the real SOC lower limit and a second preset voltage, wherein the pre-action end voltage is less than the pre-action start voltage.

[0009] Further, in some embodiments, after judging whether the current environmental temperature is in the preset normal temperature interval, the method further comprises: judging whether the current environmental temperature is in a preset low temperature interval; if the current environmental temperature is in the preset low temperature interval, obtaining a battery available capacity retention rate corresponding to the current environmental temperature; and obtaining the target SOC lower limit according to the battery available capacity retention rate corresponding to the current environmental temperature.

[0010] Further, in some embodiments, the determining the pre-action start voltage and the pre-action end voltage according to the target SOC lower limit and / or the vehicle demand power comprises: determining a third voltage according to the target SOC lower limit, and obtaining the pre-action end voltage according to a sum of the third voltage and a third preset voltage; determining a demand SOC when the vehicle demand power is satisfied, and obtaining the pre-action start voltage according to a difference between a fourth voltage corresponding to the demand SOC and a fourth preset voltage.

[0011] Further, in some embodiments, after determining the pre-action start voltage and the pre-action end voltage according to the target SOC lower limit and / or the vehicle demand power, the method further comprises: obtaining a real-time voltage of the vehicle; when the real-time voltage reaches the pre-action start voltage, limiting the available power of the vehicle based on a preset power reduction strategy, and reducing the available power of the vehicle to a preset minimum power when a new real-time voltage reaches the pre-action end voltage.

[0012] The battery system discharge lower limit determination method provided by the embodiment of the present application determines the temperature interval in which the current environmental temperature is located and the target SOC lower limit of the battery system corresponding to the temperature interval by obtaining the current environmental temperature of the battery system and the vehicle demand power under the vehicle discharge working condition, and then determines the pre-action start voltage and the pre-action end voltage according to the target SOC lower limit, thereby obtaining the discharge lower limit determination result of the battery system. The method solves the problem that the vehicle battery endurance decays too fast caused by battery over-discharge or under-voltage in the related art, improves the available endurance mileage of the vehicle battery, and improves the safety of the battery.

[0013] A second aspect of the present invention provides a method and apparatus for determining the lower discharge limit of a battery system. The apparatus includes: an acquisition module for acquiring the current ambient temperature of the battery system and the vehicle's power demand when the vehicle is in a discharge condition at the current ambient temperature; a calculation module for determining the temperature range of the current ambient temperature and determining the target SOC lower limit of the battery system based on the temperature range of the current ambient temperature; and a generation module for determining a pre-action start voltage and a pre-action end voltage based on the target SOC lower limit and / or the vehicle's power demand, so as to obtain the result of determining the lower discharge limit of the battery system based on the target SOC lower limit, the pre-action start voltage, and the pre-action end voltage.

[0014] Furthermore, in some embodiments, the calculation module is specifically used to: determine whether the current ambient temperature is within a preset normal temperature range; if the current ambient temperature is within the preset normal temperature range, obtain the vehicle's total power demand and the SOC accuracy of the battery system under discharge conditions; and determine the target SOC lower limit based on the smaller value between the vehicle's total power demand and the SOC accuracy.

[0015] Further, in some embodiments, the generation module is specifically used to: determine a first voltage corresponding to the target SOC lower limit, and obtain the pre-action start voltage based on the difference between the first voltage and a first preset voltage; determine the actual SOC lower limit of the battery system based on the current ambient temperature, and obtain the pre-action end voltage based on the sum of a second voltage corresponding to the actual SOC lower limit and a second preset voltage, wherein the pre-action end voltage is less than the pre-action start voltage.

[0016] Furthermore, in some embodiments, after determining whether the current ambient temperature is within the preset normal temperature range, the calculation module is further configured to: determine whether the current ambient temperature is within the preset low temperature range; if the current ambient temperature is within the preset low temperature range, obtain the battery usable capacity retention rate corresponding to the current ambient temperature; and obtain the target SOC lower limit based on the battery usable capacity retention rate corresponding to the current ambient temperature.

[0017] Furthermore, in some embodiments, the generation module is specifically used to: determine a third voltage based on the target SOC lower limit, and obtain the pre-action end voltage based on the sum of the third voltage and the third preset voltage; determine the required SOC when the vehicle's required power is met, and obtain the pre-action start voltage based on the difference between the fourth voltage corresponding to the required SOC and the fourth preset voltage.

[0018] Furthermore, in some embodiments, after determining the pre-action start voltage and pre-action end voltage based on the target SOC lower limit and / or the vehicle's required power, the generation module is further configured to: acquire the vehicle's real-time voltage; when the real-time voltage reaches the pre-action start voltage, limit the vehicle's available power based on a preset power reduction strategy, and when the new real-time voltage reaches the pre-action end voltage, reduce the vehicle's available power to a preset minimum power.

[0019] The battery system discharge lower limit determination device provided in this embodiment of the invention obtains the current ambient temperature of the battery system and the vehicle's required power under the vehicle's discharge conditions, determines the temperature range of the current ambient temperature and the corresponding target SOC lower limit of the battery system, and then determines the pre-action start voltage and pre-action end voltage accordingly, thereby obtaining the battery system discharge lower limit determination result. This solves the problem in related technologies that easily leads to excessively rapid degradation of vehicle battery range due to over-discharge or under-voltage, improves the usable driving range of the vehicle battery, and enhances battery safety.

[0020] A third aspect of the present invention provides an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method for determining the lower discharge limit of a battery system as described in the above embodiments.

[0021] A fourth aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, which is executed by a processor to implement the method for determining the lower discharge limit of a battery system as described in the above embodiments.

[0022] A fifth aspect of the present invention provides a computer program product, including a computer program that is executed to implement the method for determining the lower discharge limit of a battery system as described in the above embodiments.

[0023] Therefore, the present invention has the following beneficial effects:

[0024] (1) The present invention simultaneously achieves dual control of SOC lower limit and voltage lower limit. SOC is used as the available lower limit of the vehicle operating condition for capacity and mileage management, and voltage is used for power management, thus providing a dual protection strategy.

[0025] (2) The present invention increases the pre-action voltage and performs power limitation in advance to prevent over-discharge and other problems caused by excessive use of the terminal, thus ensuring safety.

[0026] (3) The pre-operation voltage is activated when the available SOC is below normal temperature. The battery capacity is relatively large at normal temperature, which can effectively prevent over-discharge and breakdown. The pre-operation voltage is activated when the available SOC is above low temperature, which can extend the vehicle's usable mileage as much as possible and alleviate the mileage reduction caused by low battery capacity at low temperature. Attached Figure Description

[0027] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0028] Figure 1 This is a flowchart of a method for determining the discharge lower limit of a battery system according to an embodiment of the present invention;

[0029] Figure 2 A flowchart of a method for determining the lower discharge limit of a battery system according to a specific embodiment of the present invention;

[0030] Figure 3 A block diagram of a battery system discharge lower limit determination device provided according to an embodiment of the present invention;

[0031] Figure 4 This is a schematic diagram of the structure of an electronic device provided according to an embodiment of the present invention. Detailed Implementation

[0032] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0033] The following describes, with reference to the accompanying drawings, a method, apparatus, device, medium, and product for determining the lower discharge limit of a battery system according to embodiments of the present invention. Addressing the problem mentioned in the background art of rapid battery range degradation due to over-discharge or under-voltage, the present invention provides a method for determining the lower discharge limit of a battery system. By acquiring the current ambient temperature of the battery system and the vehicle's required power under discharge conditions, the method determines the temperature range of the current ambient temperature and the corresponding target SOC lower limit of the battery system. Based on this, the method determines the pre-action start voltage and pre-action end voltage, thereby obtaining the result of determining the lower discharge limit of the battery system. This solves the problem of rapid battery range degradation due to over-discharge or under-voltage in related technologies, improves the usable driving range of the vehicle battery, and enhances battery safety.

[0034] Specifically, Figure 1 This is a flowchart of a method for determining the lower discharge limit of a battery system according to an embodiment of the present invention.

[0035] likeFigure 1 As shown, the method for determining the lower discharge limit of this battery system includes the following steps:

[0036] In step S101, the current ambient temperature of the battery system and the vehicle's required power when the vehicle is in discharge mode at the current ambient temperature are obtained.

[0037] Among them, the battery system refers to the vehicle's Battery Management System (BMS); the current ambient temperature refers to the ambient temperature at which the battery system is located under vehicle discharge conditions; and the vehicle's power demand under discharge conditions refers to the battery power capacity required by the battery management system under vehicle discharge conditions.

[0038] It should be understood that, in order to ensure the economic efficiency of vehicle use, the battery power capacity required for the vehicle's discharge conditions must be considered to prevent the battery management system (BMS software) from allowing an excessively high power output when the actual current battery capacity is insufficient, which could lead to over-discharge and undervoltage situations during high-power discharge.

[0039] In step S102, the temperature range of the current ambient temperature is determined, and the target SOC lower limit of the battery system is determined based on the temperature range of the current ambient temperature.

[0040] In some embodiments, determining the temperature range of the current ambient temperature and determining the target SOC lower limit of the battery system based on the temperature range of the current ambient temperature includes: determining whether the current ambient temperature is within a preset normal temperature range; if the current ambient temperature is within the preset normal temperature range, obtaining the vehicle's required power and the SOC accuracy of the battery system under discharge conditions; and determining the target SOC lower limit based on the smaller value between the vehicle's required power and the SOC accuracy.

[0041] Among them, the SOC accuracy of the battery system is the deviation between the displayed SOC value of the vehicle battery and the actual SOC value of the vehicle battery. The target SOC lower limit refers to the lowest SOC threshold that can maintain the normal operation of the vehicle under the discharge condition.

[0042] Specifically, the State of Charge (SOC) is determined by real-time acquisition of current and voltage data combined with BMS calculations. There may be deviations in calculation accuracy, which are unavoidable. It is necessary to establish a usable lower limit based on these deviations to prevent over-discharge of the battery system due to excessive vehicle use when the calculated SOC is too high, resulting in a discrepancy between the actual capacity of the battery system and the table lookup capability. For example, the current SOC deviation for ternary lithium and lithium iron phosphate systems is typically 5%. If 0% is used as the usable lower limit for the battery itself, then using 5% SOC as the usable lower limit for the entire vehicle can effectively prevent battery over-discharge problems. To ensure the usable capacity of the entire vehicle, considering both the vehicle's power requirements and SOC accuracy, the usable lower limit of SOC can be set at 3%.

[0043] It should be noted that even when the usable lower limit of SOC is set to 3%, there is still a risk of SOC deviation. That is, when the actual SOC is 3%, the currently usable SOC is 0% (i.e., usable SOC = actual SOC - 3%), and the displayed SOC is 5% (i.e., displayed SOC = usable SOC ± 5%). At this time, discharging at the same 20kW may trigger the lower voltage limit, which will still cause undervoltage and other problems. Therefore, a control strategy for the lower voltage limit needs to be introduced.

[0044] In step S103, the pre-action start voltage and pre-action end voltage are determined based on the target SOC lower limit and / or the vehicle's required power, so as to obtain the battery system's discharge lower limit determination result based on the target SOC lower limit, the pre-action start voltage, and the pre-action end voltage.

[0045] Among them, the pre-action start voltage refers to the voltage at which the available power is limited after the battery's usable SOC lower limit is reached, and the pre-action end voltage refers to the voltage at which the usable power is limited to a smaller state before the battery reaches the usable voltage lower limit. It should be understood that, because the voltage acquisition accuracy is high and the acquisition error is small, voltage control can effectively avoid the problem of over-discharge caused by the power lookup table value being too large and the actual capacity being insufficient when the SOC deviation is serious.

[0046] It's important to note that battery voltage is a crucial indicator of battery performance. It represents the battery's internal charge level; a high voltage indicates a high state of charge (SOC), while a low voltage indicates a low SOC. Furthermore, the voltage measurement accuracy is very high, ranging from 0.001 to 0.005V, accurately reflecting the battery's current status.

[0047] In some embodiments, determining the pre-action start voltage and pre-action end voltage based on the target SOC lower limit and / or the vehicle's required power includes: determining a first voltage corresponding to the target SOC lower limit, and obtaining the pre-action start voltage based on the difference between the first voltage and a first preset voltage; determining the actual SOC lower limit of the battery system based on the current ambient temperature, and obtaining the pre-action end voltage based on the sum of a second voltage corresponding to the actual SOC lower limit and a second preset voltage, wherein the pre-action end voltage is less than the pre-action start voltage.

[0048] The first voltage corresponding to the target SOC lower limit refers to the voltage corresponding to the battery cell's usable SOC at the preset value, and the second voltage refers to the voltage corresponding to the battery cell's actual SOC at 0. The first preset voltage is the voltage value used to adjust the pre-action start voltage, and the second preset voltage is the voltage value used to adjust the pre-action end voltage. It should be noted that if the pre-action start voltage is too high, it will start limiting the usable power before the usable lower limit. If the pre-action start voltage is too low, it will limit the power too late, resulting in insufficient time to limit the power and still having the risk of undervoltage. If the pre-action end voltage is set too high, it will cause the end power to decay too quickly, resulting in a poor user experience and reduced usable electricity, with little contribution to the overall vehicle economy. If the pre-action end voltage is set too low, it will exceed the battery's usage boundary, resulting in insufficient time to limit the power and still having the risk of undervoltage.

[0049] For example, the first preset voltage in this embodiment of the invention can be set to the allowable power decay from the current lookup power to the pre-action end voltage. The decay can be rate-limited. The first preset voltage can be selected as -100mV. The voltage corresponding to the actual SOC of the battery cell is 0 is 2.5V (i.e., the second voltage). The voltage corresponding to the usable SOC of the battery cell is the preset value is 3.0V (i.e., the first voltage). The pre-action start voltage V1 = 3.0V - 100mV = 2.9V. The second preset voltage can be selected as +100mV. The pre-action end voltage V2 = 2.5 + 100mV = 2.6V.

[0050] It should be understood that in cold regions, the ambient temperature in winter may be too low. At this time, the lower limit voltage design strategy in the normal temperature range cannot meet the vehicle's needs. Therefore, it is also necessary to consider the lower limit voltage design strategy for vehicles in low temperature environments.

[0051] Furthermore, in some embodiments, after determining whether the current ambient temperature is within a preset normal temperature range, the method further includes: determining whether the current ambient temperature is within a preset low temperature range; if the current ambient temperature is within the preset low temperature range, obtaining the battery usable capacity retention rate corresponding to the current ambient temperature; and obtaining the target SOC lower limit based on the battery usable capacity retention rate corresponding to the current ambient temperature.

[0052] Among them, the battery usable capacity retention rate refers to the ratio between the actual usable state of charge (SOC) of the battery cell and the theoretical state of charge (SOC) of the battery cell.

[0053] Furthermore, in some embodiments, determining the pre-action start voltage and pre-action end voltage based on the target SOC lower limit and / or the vehicle's required power includes: determining a third voltage based on the target SOC lower limit, and obtaining the pre-action end voltage based on the sum of the third voltage and a third preset voltage; determining the required SOC when the vehicle's required power is met, and obtaining the pre-action start voltage based on the difference between the fourth voltage corresponding to the required SOC and a fourth preset voltage.

[0054] Among them, the third voltage refers to the voltage corresponding to the lower limit of the actual usable SOC of the battery cell under low temperature conditions, and the fourth voltage refers to the voltage corresponding to the required SOC when the power demand of the whole vehicle is met.

[0055] For example, if the capacity retention rate at -10℃ is 85%, then the lower limit of the actual usable SOC at -10℃ is 1 - 85% = 15%, and the corresponding voltage is 2.5V. The SOC at -10℃ that can meet the 20kW discharge capacity is 20%, corresponding to a voltage of 3.2V. Therefore, if the pre-action start voltage is set below 20% SOC, V1 = 3.2V - 100mV = 3.1V. If the pre-action end voltage is set above 15% SOC, V2 = 2.5V + 100mV = 2.6V.

[0056] Furthermore, in some embodiments, after determining the pre-action start voltage and pre-action end voltage based on the target SOC lower limit and / or the vehicle's required power, the method further includes: acquiring the vehicle's real-time voltage; when the real-time voltage reaches the pre-action start voltage, limiting the vehicle's available power based on a preset power reduction strategy; and when the new real-time voltage reaches the pre-action end voltage, reducing the vehicle's available power to a preset minimum power.

[0057] To enable those skilled in the art to better understand the method for determining the lower discharge limit of the battery system according to the embodiments of the present invention, the following explanation will be provided in conjunction with specific embodiments.

[0058] Figure 2 A flowchart of a method for determining the lower discharge limit of a battery system according to a specific embodiment of the present invention is shown below. Figure 2As shown, the design begins with the lower limit of normal temperature operation, divided into two branches: determining the lower limit of normal temperature SOC and designing the lower limit of normal temperature voltage. Determining the lower limit of normal temperature SOC requires consideration of the overall vehicle operating conditions and SOC accuracy. The design of the lower limit of normal temperature voltage involves the pre-action start voltage V1 and the pre-action end voltage V2. After completing the normal temperature design, the design of the lower limit of low temperature operation is carried out, including low temperature SOC design and low temperature voltage design. Battery performance changes in low-temperature environments, requiring separate design of the lower limits of SOC and voltage to ensure the safe and stable operation of the battery under low-temperature conditions.

[0059] According to the battery system discharge lower limit determination method provided in the embodiments of the present invention, by obtaining the current ambient temperature of the battery system and the vehicle's required power under the vehicle discharge conditions, the temperature range of the current ambient temperature and the corresponding target SOC lower limit of the battery system are determined, and then the pre-action start voltage and pre-action end voltage are determined accordingly, thereby obtaining the discharge lower limit determination result of the battery system. This solves the problem in related technologies that easily leads to excessively rapid degradation of vehicle battery range due to over-discharge or under-voltage, improves the usable driving range of the vehicle battery, and enhances battery safety.

[0060] Next, the discharge lower limit determination device for a battery system according to an embodiment of the present invention is described with reference to the accompanying drawings.

[0061] Figure 3 A block diagram of a battery system discharge lower limit determination device provided according to an embodiment of the present invention.

[0062] like Figure 3 As shown, the battery system discharge lower limit determination device 10 includes: an acquisition module 100, a calculation module 200, and a generation module 300.

[0063] The acquisition module 100 is used to acquire the current ambient temperature of the battery system and the vehicle's required power when the vehicle is in discharge condition at the current ambient temperature; the calculation module 200 is used to determine the temperature range of the current ambient temperature and determine the target SOC lower limit of the battery system based on the temperature range of the current ambient temperature; the generation module 300 is used to determine the pre-action start voltage and pre-action end voltage based on the target SOC lower limit and / or the vehicle's required power, so as to obtain the result of determining the discharge lower limit of the battery system based on the target SOC lower limit, the pre-action start voltage, and the pre-action end voltage.

[0064] Furthermore, in some embodiments, the calculation module 200 is specifically used to: determine whether the current ambient temperature is within a preset normal temperature range; if the current ambient temperature is within the preset normal temperature range, obtain the vehicle's required power and the SOC accuracy of the battery system under discharge conditions; and determine the target SOC lower limit based on the smaller value between the vehicle's required power and the SOC accuracy.

[0065] Furthermore, in some embodiments, the generation module 300 is specifically used to: determine a first voltage corresponding to the target SOC lower limit, and obtain a pre-action start voltage based on the difference between the first voltage and a first preset voltage; determine the actual SOC lower limit of the battery system based on the current ambient temperature, and obtain a pre-action end voltage based on the sum of a second voltage corresponding to the actual SOC lower limit and a second preset voltage, wherein the pre-action end voltage is less than the pre-action start voltage.

[0066] Furthermore, in some embodiments, after determining whether the current ambient temperature is within a preset normal temperature range, the calculation module 200 is further configured to: determine whether the current ambient temperature is within a preset low temperature range; if the current ambient temperature is within the preset low temperature range, obtain the battery usable capacity retention rate corresponding to the current ambient temperature; and obtain the target SOC lower limit based on the battery usable capacity retention rate corresponding to the current ambient temperature.

[0067] Furthermore, in some embodiments, the generation module 300 is also configured to: determine a third voltage based on the target SOC lower limit, and obtain a pre-action end voltage based on the sum of the third voltage and the third preset voltage; determine the required SOC when the vehicle's required power is met, and obtain a pre-action start voltage based on the difference between the fourth voltage corresponding to the required SOC and the fourth preset voltage.

[0068] Furthermore, in some embodiments, after determining the pre-action start voltage and pre-action end voltage based on the target SOC lower limit and / or the vehicle's required power, the generation module 300 is further configured to: acquire the vehicle's real-time voltage; when the real-time voltage reaches the pre-action start voltage, limit the vehicle's available power based on a preset power reduction strategy, and when the new real-time voltage reaches the pre-action end voltage, reduce the vehicle's available power to a preset minimum power.

[0069] It should be noted that the above explanation of the method embodiment for determining the lower discharge limit of a battery system also applies to the device for determining the lower discharge limit of a battery system in this embodiment, and will not be repeated here.

[0070] The battery system discharge lower limit determination device proposed in this embodiment of the invention obtains the current ambient temperature of the battery system and the vehicle's required power under the vehicle's discharge conditions, determines the temperature range of the current ambient temperature and the corresponding target SOC lower limit of the battery system, and then determines the pre-action start voltage and pre-action end voltage accordingly, thereby obtaining the battery system discharge lower limit determination result. This solves the problem in related technologies that easily leads to excessively rapid degradation of vehicle battery range due to over-discharge or under-voltage, improves the usable driving range of the vehicle battery, and enhances battery safety.

[0071] Figure 4This is a schematic diagram of an electronic device provided according to an embodiment of the present invention. The electronic device may include:

[0072] The memory 401, the processor 402, and the computer program stored on the memory 401 and capable of running on the processor 402.

[0073] When the processor 402 executes the program, it implements the method for determining the lower discharge limit of the battery system provided in the above embodiments.

[0074] Furthermore, the electronic device also includes:

[0075] Communication interface 403 is used for communication between memory 401 and processor 402.

[0076] The memory 401 is used to store computer programs that can run on the processor 402.

[0077] The memory 401 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0078] If the memory 401, processor 402, and communication interface 403 are implemented independently, then the communication interface 403, memory 401, and processor 402 can be interconnected via a bus to complete communication between them. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be divided into address buses, data buses, control buses, etc. For ease of representation, Figure 4 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0079] Optionally, in a specific implementation, if the memory 401, processor 402, and communication interface 403 are integrated on a single chip, then the memory 401, processor 402, and communication interface 403 can communicate with each other through an internal interface.

[0080] Processor 402 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement embodiments of the present invention.

[0081] In addition, embodiments of the present invention also provide a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-described method for determining the lower discharge limit of a battery system.

[0082] In addition, embodiments of the present invention also provide a computer program product, including a computer program, which is executed to implement the above-described method for determining the lower discharge limit of a battery system.

[0083] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0084] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0085] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more N executable instructions for implementing custom logic functions or processes, and the scope of preferred embodiments of the invention includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of the invention pertain.

[0086] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0087] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

Claims

1. A method for determining the lower discharge limit of a battery system, characterized in that, Includes the following steps: Obtain the current ambient temperature of the battery system and the vehicle's power demand when the vehicle is in discharge mode at the current ambient temperature; Determine the temperature range of the current ambient temperature, and determine the target SOC lower limit of the battery system based on the temperature range of the current ambient temperature; The pre-action start voltage and pre-action end voltage are determined based on the target SOC lower limit and / or the vehicle power demand, so as to obtain the discharge lower limit determination result of the battery system based on the target SOC lower limit, the pre-action start voltage and the pre-action end voltage.

2. The method according to claim 1, characterized in that, Determining the temperature range of the current ambient temperature and determining the target SOC lower limit of the battery system based on the temperature range of the current ambient temperature includes: Determine whether the current ambient temperature is within a preset normal temperature range; If the current ambient temperature is within the preset normal temperature range, then the vehicle's total power demand and the SOC accuracy of the battery system under discharge conditions are obtained. The target lower limit of SOC is determined based on the smaller of the required power of the vehicle and the SOC accuracy.

3. The method according to claim 2, characterized in that, The step of determining the pre-action start voltage and pre-action end voltage based on the target SOC lower limit and / or the vehicle required power includes: Determine the first voltage corresponding to the target SOC lower limit, and obtain the pre-action start voltage based on the difference between the first voltage and the first preset voltage; The true lower limit of the SOC of the battery system is determined based on the current ambient temperature, and the pre-action end voltage is obtained based on the sum of the second voltage corresponding to the true lower limit of the SOC and the second preset voltage, wherein the pre-action end voltage is less than the pre-action start voltage.

4. The method according to claim 2, characterized in that, After determining whether the current ambient temperature is within the preset normal temperature range, the method further includes: Determine whether the current ambient temperature is within a preset low temperature range; If the current ambient temperature is within the preset low temperature range, then obtain the battery usable capacity retention rate corresponding to the current ambient temperature; The target SOC lower limit is obtained based on the battery's usable capacity retention rate corresponding to the current ambient temperature.

5. The method according to claim 4, characterized in that, The step of determining the pre-action start voltage and pre-action end voltage based on the target SOC lower limit and / or the vehicle required power includes: The third voltage is determined based on the target SOC lower limit, and the pre-action end voltage is obtained based on the sum of the third voltage and the third preset voltage. Determine the required SOC when the required power of the whole vehicle is met, and obtain the pre-action start voltage based on the difference between the fourth voltage and the fourth preset voltage corresponding to the required SOC.

6. The method according to any one of claims 1-5, characterized in that, After determining the pre-action start voltage and pre-action end voltage based on the target SOC lower limit and / or the vehicle required power, the method further includes: Obtain the real-time voltage of the vehicle; When the real-time voltage reaches the pre-action start voltage, the available power of the vehicle is limited based on a preset power reduction strategy, and when the new real-time voltage reaches the pre-action end voltage, the available power of the vehicle is reduced to a preset minimum power.

7. A device for determining the lower discharge limit of a battery system, characterized in that, The device includes: The acquisition module is used to acquire the current ambient temperature of the battery system and the vehicle's power demand when the vehicle is in discharge condition at the current ambient temperature. The calculation module is used to determine the temperature range of the current ambient temperature and to determine the target SOC lower limit of the battery system based on the temperature range of the current ambient temperature. The generation module is used to determine the pre-action start voltage and pre-action end voltage based on the target SOC lower limit and / or the vehicle demand power, so as to obtain the discharge lower limit determination result of the battery system based on the target SOC lower limit, the pre-action start voltage and the pre-action end voltage.

8. An electronic device, characterized in that, include: A memory, a processor, and a computer program stored in the memory and executable on the processor, the processor executing the program to implement the method for determining the lower discharge limit of a battery system as described in any one of claims 1-6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by the processor to implement the method for determining the lower discharge limit of the battery system as described in any one of claims 1-6.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the method for determining the lower discharge limit of the battery system as described in any one of claims 1-6.

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