Control Method, Control Device, Storage Medium and Vehicle of Power Battery System

Abstract

The present invention discloses a control method, a control device, a storage medium, and a vehicle for a power battery system. There are N temperature regions in the power battery system, and at least one battery cell monomer is provided in each temperature region. The method includes: obtaining the first temperature and the first voltage of each battery cell monomer in each temperature region; determining the discharge cut-off voltage of the corresponding temperature region according to the first temperature in each temperature region; when the minimum value of the first voltage in any temperature region is less than or equal to the corresponding discharge cut-off voltage, starting an under-voltage strategy and / or an SOC correction strategy to control the power battery system. Thus, this method can achieve precise control of the battery cell monomers, maximize the performance of the power battery system, and increase the low-temperature discharge capacity of the power battery system.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicles, and in particular, to a control method for a power battery system, a computer-readable storage medium, a control device for a power battery system, and a vehicle. Background Art

[0002] In the related art, in order not to exceed the safe use boundary of a single battery cell, when formulating the control strategy of a BMS (Battery Management System), generally, the discharge cut-off voltage corresponding to the highest temperature of a single battery cell is used as the voltage control condition during the discharge process. Although this control method can effectively prevent the risk of over-discharge of a single battery cell, it will cause a reduction in the low-temperature discharge capacity of the power battery system, affect the low-temperature cruising range of the whole vehicle, thereby reducing the product competitiveness and easily causing complaints from market customers.

[0003] In addition, in order to increase the low-temperature discharge capacity, generally, the discharge cut-off voltage corresponding to the lowest temperature of a single battery cell is used as the voltage control condition during the discharge process. However, when using this control method, there is a risk of over-discharge of the battery cell. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems in the related art to some extent. For this reason, the first object of the present invention is to propose a control method for a power battery system, which can achieve precise control of a single battery cell, maximize the performance of the power battery system, and increase the low-temperature discharge capacity of the power battery system.

[0005] The second object of the present invention is to propose a computer-readable storage medium.

[0006] The third object of the present invention is to propose a control device for a power battery system.

[0007] The fourth object of the present invention is to propose a vehicle.

[0008] To achieve the above object, an embodiment of the first aspect of the present invention proposes a control method for a power battery system. There are N temperature regions in the power battery system, and at least one single battery cell is provided in each temperature region, where N is a positive integer greater than 1. The method includes: obtaining the first temperature and the first voltage of each single battery cell in each temperature region; determining the discharge cut-off voltage of the corresponding temperature region according to the first temperature in each temperature region; when the minimum value of the first voltage in any temperature region is less than or equal to the corresponding discharge cut-off voltage, starting an under-voltage strategy and / or an SOC correction strategy to control the power battery system.

[0009] The control method of the power battery system according to the embodiments of the present invention can achieve precise control of each single battery cell, maximize the performance of the power battery system, and improve the low-temperature discharge capacity of the power battery system.

[0010] To achieve the above object, an embodiment of the second aspect of the present invention provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the control method of the power battery system is implemented.

[0011] To achieve the above object, an embodiment of the third aspect of the present invention provides a control device for a power battery system. The power battery system has N temperature regions, and at least one single battery cell is provided in each temperature region, where N is a positive integer greater than 1. The device includes: an acquisition module, configured to acquire the first temperature and the first voltage of each single battery cell in each temperature region; a determination module, configured to determine the discharge cut-off voltage of the corresponding temperature region according to the first temperature in each temperature region; and a control module, configured to, when the minimum value of the first voltage in any temperature region is less than or equal to the corresponding discharge cut-off voltage, start an under-voltage strategy and / or an SOC correction strategy to control the power battery system.

[0012] The control device of the power battery system according to the embodiments of the present invention can achieve precise control of each single battery cell, maximize the performance of the power battery system, and improve the low-temperature discharge capacity of the power battery system.

[0013] To achieve the above object, an embodiment of the fourth aspect of the present invention provides a vehicle, including: the control device of the power battery system.

[0014] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. Description of the Drawings

[0015] Figure 1 is a schematic flowchart of the control method of the power battery system according to an embodiment of the present invention;

[0016] Figure 2 is a schematic structural diagram of the control device of the power battery system according to an embodiment of the present invention. Detailed Embodiments

[0017] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the drawings, where 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 drawings are exemplary and are intended to explain the present invention, and should not be construed as a limitation of the present invention.

[0018] The following refers to the attached Figure 1-2 Describe a control method, a control device, a storage medium, and a vehicle for a power battery system according to an embodiment of the present invention.

[0019] There are N temperature regions in the power battery system, and at least one battery cell monomer is provided in each temperature region, where N is a positive integer greater than 1.

[0020] As an example, the N temperature regions are obtained in the following manner: obtaining the second temperature of each battery cell monomer in the power battery system; performing temperature distribution statistics on the second temperature; and dividing the temperature regions of the power battery system according to the principle of minimizing the temperature difference based on the statistical results to obtain N temperature regions. Among them, the statistical results include the temperature magnitude sequence of the second temperature. Dividing the temperature regions of the power battery system according to the principle of minimizing the temperature difference based on the statistical results includes: calculating the difference between all two adjacent second temperatures in the temperature magnitude sequence; segmenting the temperature magnitude sequence according to the difference, and obtaining the temperature region division result according to the segmentation result, where the difference in each segment is less than the difference between the second temperature in this segment and the second temperature in the adjacent segment.

[0021] Specifically, the second temperature of each battery cell monomer in the power battery system can be obtained through a temperature sensor, the temperature magnitude distribution of the second temperature is statistically analyzed to obtain the temperature magnitude sequence of the second temperature, the difference between all two adjacent second temperatures in the temperature magnitude sequence is calculated, the temperature magnitude sequence is segmented according to the difference, and the temperature region division result is obtained according to the segmentation result, where the difference in each segment is less than the difference between the second temperature in this segment and the second temperature in the adjacent segment. Thus, by performing temperature distribution statistics on the second temperature of each battery cell monomer in the power battery system, dividing the temperature regions of the power battery system according to the principle of minimizing the temperature difference based on the statistical results, N temperature regions are obtained. It should be noted that N can be a fixed value or a non-fixed value.

[0022] For example, the second temperatures of each battery cell monomer in the power battery system (see the second temperature numbers 1, 2, 3, 4, 5, 6 of each battery cell monomer in Table 1) are sorted in size, and the obtained statistical result is the temperature magnitude sequence of 3, 2, 5, 1, 6, 4. Among them, the difference between 3 and 2 is less than the difference between 2 and 5, the maximum difference among 5, 1, and 6 is less than the difference between 2 and 5, and the difference between 2 and 5 is equal to the difference between 6 and 4. Then, the battery cell monomers N3_1 - N3_num and N2_1 - N2_num corresponding to 3 and 2 are in one region, the battery cell monomers N5_1 - N5_num, N1_1 - N1_num, and N6_1 - N6_num corresponding to 5, 1, and 6 are in one region, and the battery cell monomers N4_1 - N4_num corresponding to 4 are in one region (see Table 1).

[0023] Table 1

[0024]

[0025] Figure 1 is a schematic flowchart of a control method for a power battery system according to an embodiment of the present invention. As Figure 1 shown, the control method for the power battery system includes the following steps:

[0026] S101. Obtain the first temperature and the first voltage of each battery cell in each temperature region.

[0027] Specifically, the first temperature of each battery cell in each temperature region can be obtained through a temperature sensor, and the first voltage of each battery cell in each temperature region can be obtained through a voltmeter.

[0028] S102. Determine the discharge cut-off voltage of the corresponding temperature region according to the first temperature in each temperature region.

[0029] Specifically, due to the characteristics of the battery cells, the polarization degrees of the battery cells at different temperatures are different. Therefore, when the power battery system is applied, the discharge cut-off voltage thresholds of the battery cells at different temperatures are different. The polarization of the battery cells at low temperatures is larger than that at normal and high temperatures, and the discharge cut-off voltage will be lower than that at normal and high temperatures. Thus, the present invention determines the minimum value of the first temperature in each temperature region; and determines the discharge cut-off voltage of the corresponding temperature region according to the temperature range where the minimum value of the first temperature is located.

[0030] In this example, determining the discharge cut-off voltage of the corresponding temperature region according to the temperature range where the minimum value of the first temperature is located may include: if the minimum value of the first temperature is less than or equal to the first preset temperature, determining that the discharge cut-off voltage of the corresponding temperature region is the first preset voltage; if the minimum value of the first temperature is greater than the first preset temperature and less than or equal to the second preset temperature, determining that the discharge cut-off voltage of the corresponding temperature region is the second preset voltage; if the minimum value of the first temperature is greater than the second preset temperature, determining that the discharge cut-off voltage of the corresponding temperature region is the third preset voltage, where the second preset voltage is greater than the first preset voltage, and the third preset voltage is greater than the second preset voltage.

[0031] Specifically, the first preset temperature can be 10°C, the second preset temperature can be 20°C, the first preset voltage can be 2.1V, the second preset voltage can be 2.5V, and the third preset voltage can be 2.8V. Referring to Table 2, if the minimum value T min of the first temperature is less than or equal to 10°C, then determine that the discharge cut-off voltage of the corresponding temperature region is 2.1V; if the minimum value T min of the first temperature is greater than 10°C and less than or equal to 20°C, then determine that the discharge cut-off voltage of the corresponding temperature region is 2.5V; if the minimum value T minIf the temperature is higher than 20°C, the discharge cut-off voltage for the corresponding temperature range is determined to be 2.8V.

[0032] Table 2

[0033] Temperature range Discharge cut-off voltage <![CDATA[T min ≤10℃]]> 2.1V <![CDATA[10 °C < T min ≤ 20 °C]]> 2.5V <![CDATA[T min > 20 °C]]> 2.8V

[0034] S103. When the minimum value of the first voltage in any temperature range is less than or equal to the corresponding discharge cut-off voltage, start the undervoltage strategy and / or the SOC correction strategy to control the power battery system.

[0035] Specifically, compared with the strategy of using the cut-off voltage corresponding to the lowest temperature T min of the battery cell as the discharge cut-off control condition, the control method of the power battery system of the present invention adopts an OR relationship in each temperature range during the discharge process. When the minimum value of the first voltage in any temperature range is less than or equal to the corresponding discharge cut-off voltage, start the undervoltage strategy and / or the SOC correction strategy to control the power battery system, effectively avoiding over-discharge of the battery cell monomers.

[0036] It should be noted that in order to more intuitively compare the power battery discharge amounts corresponding to the two control strategies, the following test items were planned:

[0037] Under the condition that the ambient temperature is 0°C, the whole vehicle conducts a real vehicle endurance mileage test verification. When reaching the end of the discharge, the following two strategies are adopted to compare the whole vehicle endurance mileage and the power battery discharge amount:

[0038] Strategy 1: Use the cut-off voltage corresponding to the highest temperature T max of the battery cell as the discharge cut-off control condition. The lowest temperature T1 min of the battery cell monomers at the end of the discharge is 9°C, the highest temperature T1 max is 16°C, and the temperature difference is 7°C. The discharge cut-off voltage corresponding to the highest temperature T1 max is 2.5V. When the BMS detects that T1 max is 16°C and the lowest voltage V1 min of the battery cell monomers at the end of the discharge is less than 2.5V, start the undervoltage strategy and the SOC correction strategy to control the power battery system. At this time, from full charge to the end of the discharge, the endurance mileage is D1, and the total battery discharge amount is E1.

[0039] In this strategy, according to data analysis, the higher the temperature, the higher the voltage corresponding to the battery cell monomer. The battery cell temperature corresponding to the lowest voltage V1 min is 9°C (the corresponding discharge cut-off voltage is 2.1V), but this control strategy is based on the lowest voltage V1 minTaking <2.5V as the discharge cut-off control condition will cause the problem that the temperature of the single battery cell and the discharge cut-off voltage of the single battery cell do not match, thus unable to maximize the discharge capacity of the power battery system and reducing the vehicle's cruising range.

[0040] Strategy 2: Adopt the control method of the power battery system of the present invention. Based on the temperature field distribution characteristics of the power battery system, divide the system into temperature regions, and perform regional control on the cell temperature and voltage. The relationship of "or" is adopted for each temperature region. Once any region triggers the discharge cut-off voltage of that region, the undervoltage strategy and SOC correction are both started.

[0041] At the end of discharge, by statistically analyzing the temperature distribution of the second temperature (see the second temperature numbers 1, 2, 3...13, 14 of each single battery cell in Table 3) of each single battery cell in the power battery system, and according to the principle of minimizing the temperature difference, divide the temperature regions of the power battery system according to the statistical results to obtain 8 temperature regions (see Table 3). When the minimum value T of the first temperature in a certain temperature region is detected to be min > 20°C, and the minimum value V of the first voltage in this temperature region is min ≤ 2.8V, or when the minimum value T of the first temperature in a certain temperature region is detected to be min greater than 10°C and less than or equal to 20°C, and the minimum value V of the first voltage in this temperature region is min ≤ 2.5V, or when the minimum value T of the first temperature in a certain temperature region is detected to be min ≤ 10°C and V in this region is min ≤ 2.1V, start the undervoltage strategy and SOC correction strategy. At this time, from full charge to the end of discharge, the cruising range is D2, and the total battery discharge is E2.

[0042] Through comparative test verification with the strategy of using the cut-off voltage corresponding to the highest single temperature T max as the discharge cut-off control condition, the control method of the power battery system of the present invention increases the vehicle's cruising range by 15 km and improves the battery discharge capacity by 2.5% at an ambient temperature of 0°C. After battery pack and vehicle-level test verification (BOL (Beginning of Life, a comprehensive physical examination of the battery at the initial stage of its life) status and reliable durability test process), the temperature region division strategy provided by the present invention is consistent with the actual temperature distribution. The present invention can also increase the low-temperature capacity retention rate at -7°C from 93% to 95%, effectively preventing the single battery cell from over-discharging and enhancing the product competitiveness.

[0043] Table 3

[0044]

[0045] In summary, for the control method of the power battery system, by obtaining the first temperature and the first voltage of each battery cell in each temperature region, determining the discharge cut-off voltage of the corresponding temperature region according to the first temperature in each temperature region, and when the minimum value of the first voltage in any temperature region is less than or equal to the corresponding discharge cut-off voltage, starting the under-voltage strategy and / or the SOC correction strategy to control the power battery system, it is possible to achieve precise control of the battery cells, maximize the performance of the power battery system, increase the low-temperature discharge capacity of the power battery system, thereby improving the low-temperature endurance of the whole vehicle, enhancing the product competitiveness, and improving the market customer experience.

[0046] The present invention also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the control method of the power battery system described above is implemented.

[0047] For the computer-readable storage medium of the embodiment of the present invention, when the computer program thereon is executed by a processor, it can achieve precise control of the battery cells, maximize the performance of the power battery system, increase the low-temperature discharge capacity of the power battery system, thereby improving the low-temperature endurance of the whole vehicle, enhancing the product competitiveness, and improving the customer experience.

[0048] Figure 2 It is a schematic structural diagram of a control device for a power battery system according to an embodiment of the present invention. There are N temperature regions in the power battery system, and at least one battery cell is provided in each temperature region, where N is a positive integer greater than 1. For example Figure 2 As shown, the control device 100 of the power battery system includes: an acquisition module 10, a determination module 20, and a control module 30. Among them, the acquisition module 10 is used to acquire the first temperature and the first voltage of each battery cell in each temperature region; the determination module 20 is used to determine the discharge cut-off voltage of the corresponding temperature region according to the first temperature in each temperature region; the control module 30 is used to start the under-voltage strategy and / or the SOC correction strategy to control the power battery system when the minimum value of the first voltage in any temperature region is less than or equal to the corresponding discharge cut-off voltage.

[0049] In an embodiment of the present invention, the acquisition module 10 can also be used to acquire the second temperature of each battery cell in the power battery system; perform temperature distribution statistics on the second temperature; and divide the power battery system into N temperature regions according to the principle of minimizing the temperature difference based on the statistical results. The statistical results include the temperature magnitude sequence of the second temperature.

[0050] In an embodiment of the present invention, the obtaining module 10 is specifically configured to calculate the difference between all two adjacent second temperatures in the temperature magnitude sequence; segment the temperature magnitude sequence according to the difference, and obtain a temperature region division result according to the segmentation result, where the difference in each segment is less than the difference between the second temperature in this segment and the second temperature in the adjacent segment.

[0051] In an embodiment of the present invention, the determining module 20 is specifically configured to determine the minimum value of the first temperature in each temperature region; determine the discharge cut-off voltage of the corresponding temperature region according to the temperature range where the minimum value of the first temperature is located.

[0052] In an embodiment of the present invention, the determining module 20 is specifically configured to determine the discharge cut-off voltage of the corresponding temperature region according to the temperature range where the minimum value of the first temperature is located, including: if the minimum value of the first temperature is less than or equal to the first preset temperature, determining that the discharge cut-off voltage of the corresponding temperature region is the first preset voltage; if the minimum value of the first temperature is greater than the first preset temperature and less than or equal to the second preset temperature, determining that the discharge cut-off voltage of the corresponding temperature region is the second preset voltage, where the second preset voltage is greater than the first preset voltage; if the minimum value of the first temperature is greater than the second preset temperature, determining that the discharge cut-off voltage of the corresponding temperature region is the third preset voltage, where the third preset voltage is greater than the second preset voltage.

[0053] It should be noted that for other specific implementation manners of the control device of the power battery system in the embodiments of the present invention, reference may be made to the above-mentioned control method of the power battery system.

[0054] In summary, the control device of the power battery system, by obtaining the first temperature and the first voltage of each battery cell monomer in each temperature region, determines the discharge cut-off voltage of the corresponding temperature region according to the first temperature in each temperature region. When the minimum value of the first voltage in any temperature region is less than or equal to the corresponding discharge cut-off voltage, the under-voltage strategy and / or the SOC correction strategy are started to control the power battery system, which can achieve precise control of the battery cell monomer, maximize the performance of the power battery system, increase the low-temperature discharge capacity of the power battery system, thereby improving the low-temperature endurance of the whole vehicle, enhancing the product competitiveness, and improving the customer experience.

[0055] The present invention also provides a vehicle, including: the control device of the above-mentioned power battery system. It should be noted that the vehicle in the embodiments of the present invention may be a pure electric vehicle type, or a PHEV (Plug-in hybrid electric vehicle), or an HEV (Hybrid Electric Vehicle).

[0056] The vehicle according to the embodiment of the present invention can achieve precise control of individual battery cells through the control device of the power battery system, maximize the performance of the power battery system, increase the low-temperature discharge capacity of the power battery system, thereby improving the low-temperature endurance of the whole vehicle, enhancing the product competitiveness, and improving the customer experience.

[0057] It should be noted that the logic and / or steps represented in the flowchart or described in other ways herein, for example, can be considered as a predefined sequence list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other systems that can fetch and execute instructions from the instruction execution system, apparatus, or device), or in combination with these instruction execution systems, apparatus, or devices. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection portion with one or more wirings (electronic device), a portable computer diskette (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other media, followed by editing, interpretation, or other appropriate processing as necessary, and then stored in a computer memory.

[0058] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware, or a combination thereof. In the above-described embodiment, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, any one or a combination of the following well-known technologies in the art can be used: discrete logic circuits having logic gate circuits for implementing logical functions on data signals, application-specific integrated circuits having appropriate combinational logic gate circuits, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0059] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples", etc., mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0060] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are based on the orientation or positional relationships shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0061] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0062] In the present invention, unless otherwise clearly specified and defined, terms such as "mounted", "connected", "coupled", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0063] In the present invention, unless otherwise clearly specified or limited, the first feature being "on" or "under" the second feature may mean that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "below" and "beneath" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the horizontal height of the first feature is less than that of the second feature.

[0064] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A control method for a power battery system, characterized in that There are N temperature regions in the power battery system, and at least one battery cell is provided in each temperature region, where N is a positive integer greater than 1. The method includes: Obtain the first temperature and the first voltage of each battery cell in each temperature region; Determine the discharge cut-off voltage of the corresponding temperature region according to the first temperature in each temperature region; When the minimum value of the first voltage in any temperature region is less than or equal to the corresponding discharge cut-off voltage, start the under-voltage strategy and / or the SOC correction strategy to control the power battery system; The N temperature regions are obtained in the following manner: Obtain the second temperature of each battery cell in the power battery system; perform temperature distribution statistics on the second temperature; according to the principle of minimizing the temperature difference, divide the power battery system into temperature regions according to the statistical results to obtain N temperature regions; where the statistical results include the temperature magnitude sequence of the second temperature, and dividing the power battery system into temperature regions according to the principle of minimizing the temperature difference includes: calculating the difference between all two adjacent second temperatures in the temperature magnitude sequence; segmenting the temperature magnitude sequence according to the difference, and obtaining the temperature region division result according to the segmentation result, where the difference in each segment is less than the difference between the second temperature in this segment and the second temperature in the adjacent segment.

2. The control method of the power battery system according to claim 1, wherein The determining the discharge cut-off voltage of the corresponding temperature region according to the first temperature in each temperature region includes: Determine the minimum value of the first temperature in each temperature region; Determine the discharge cut-off voltage of the corresponding temperature region according to the temperature interval where the minimum value of the first temperature is located.

3. The control method of the power battery system according to claim 2, characterized in that, The determining the discharge cut-off voltage of the corresponding temperature region according to the temperature interval where the minimum value of the first temperature is located includes: If the minimum value of the first temperature is less than or equal to the first preset temperature, determine that the discharge cut-off voltage of the corresponding temperature region is the first preset voltage; If the minimum value of the first temperature is greater than the first preset temperature and less than or equal to the second preset temperature, determine that the discharge cut-off voltage of the corresponding temperature region is the second preset voltage, where the second preset voltage is greater than the first preset voltage; If the minimum value of the first temperature is greater than the second preset temperature, determine that the discharge cut-off voltage of the corresponding temperature region is the third preset voltage, where the third preset voltage is greater than the second preset voltage.

4. The control method of the power battery system according to claim 3, characterized in that, The first preset temperature is 10°C, and the second preset temperature is 20°C.

5. The control method of the power battery system according to claim 3, wherein, The first preset voltage is 2.1V, the second preset voltage is 2.5V, and the third preset voltage is 2.8V.

6. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the control method of the power battery system according to any one of claims 1-5.

7. A control device for a power battery system, characterized in that, There are N temperature regions in the power battery system, and at least one battery cell is provided in each temperature region, where N is a positive integer greater than 1. The device includes: An acquisition module for acquiring the first temperature and the first voltage of each battery cell in each temperature region; A determination module for determining the discharge cut-off voltage of the corresponding temperature region according to the first temperature in each temperature region; A control module, configured to start an under-voltage strategy and / or an SOC correction strategy to control the power battery system when the minimum value of the first voltage in any temperature region is less than or equal to the corresponding discharge cut-off voltage; The N temperature regions are obtained in the following manner: acquiring the second temperature of each single battery cell in the power battery system; performing temperature distribution statistics on the second temperature; according to the principle of minimizing temperature difference, dividing the temperature regions of the power battery system based on the statistical results to obtain N temperature regions; wherein, the statistical results include the temperature magnitude sequence of the second temperature, and dividing the temperature regions of the power battery system according to the principle of minimizing temperature difference based on the statistical results includes: calculating the difference between all two adjacent second temperatures in the temperature magnitude sequence; segmenting the temperature magnitude sequence according to the difference, and obtaining the temperature region division result according to the segmentation result, wherein the difference in each segment is less than the difference between the second temperature in this segment and the second temperature in the adjacent segment.

8. A vehicle, characterized in that, Including: The control device for a power battery system according to claim 7.

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